News - China Industry Valves Supplier & Manufacturer

Understand API 609 Butterfly Valves Types

A butterfly valve is used to shut off or modulate the flow of a fluid (isolation and regulation). API 609 Centric butterfly valves (soft seated) are preferred to gate and ball valves for low-pressure and non-critical applications as they are cheaper, lighter, and easier to install. Eccentric butterfly valves (double offset and triple offset valves) with metal seats have surged in popularity and compete with globe and ball valves for some applications.

BUTTERFLY VALVE

WHAT IS A BUTTERFLY VALVE

A butterfly valve is a type of flow control device used to regulate or isolate fluid flow through a pipe. It consists of a rotating disc, known as the butterfly, which is mounted on a rod. When the valve is fully open, the disc is turned parallel to the flow of fluid, allowing for almost unrestricted flow. When the valve is closed, the disc is rotated so that it completely blocks off the flow path.

Key Features Of Butterfly Valves

Compact and Lightweight: Butterfly valves have a compact design and are lighter than some other types of valves, such as ball or gate valves, making them easier to install and requiring less support.
Quick Operation: The disc rotates 90 degrees to open or close, providing a quick action that can be beneficial in both manual and automated operations.
Cost-Effective: Generally, butterfly valves are less expensive than other valve types, especially for large-diameter pipes.
Versatility: Suitable for a wide range of applications, handling liquids, gases, and slurries. They can be used in various industries, including water and wastewater treatment, chemical processing, and HVAC systems.

Types Of Butterfly Valves

Concentric Butterfly Valves: Also known as rubber-lined butterfly valves, these have a resilient rubber seat with a metal disc. Suitable for lower pressure and temperature applications.
Double Offset Butterfly Valves: Designed with two offsets to reduce wear on the valve seat and disc during operation, enhancing longevity and performance. Suitable for higher pressure and temperature applications.
Triple Offset Butterfly Valves: Feature a third offset that creates a cone-shaped sealing surface, allowing for metal-to-metal sealing, minimal wear, and use in high temperature and pressure applications.

Operation

Butterfly valves can be operated manually with a handle, or they can be actuated pneumatically, electrically, or hydraulically for automatic operation. The choice of operation mode depends on the application’s requirements, including the need for precise control, the size of the valve, and the operating environment.

Applications

Butterfly valves are versatile and can be used across a wide range of applications, including:

Isolating and Regulating Flow: In piping systems for water supply, wastewater treatment, and industrial processes.
HVAC: For regulating airflow in heating, ventilation, and air conditioning systems.
Chemical Processing: For controlling the flow of various chemicals and slurries.

In summary, butterfly valves are a popular choice for many flow control applications due to their compact design, cost-effectiveness, and versatility. They are suitable for a wide variety of fluids and gases and can be tailored for specific operational needs with different types and materials.

A butterfly valve is a regulating and shut-off device that can be an alternative, in some applications, with globe and ball valves.

Classification Of Butterfly Valves

Butterfly valves may be classified based on multiple features:

Design: centric, double eccentric, triple eccentric
Valve-end connection type: wafer, lug (semi or full), flanged and double flanged
Seat material: soft (example: Teflon, Buna, rubber, etc) or metal-to-metal (SS304, SS316)
Body and disc materials (from cast iron to high nickel alloys)
Type of valves’ actuation: manual (lever, gear, worm gear) and actuated (electric, pneumatic, hydraulic, and gas-over-oil types)

Types of butterfly valves

Butterfly valves can be used for a wide range of applications such as water supply, wastewater treatment, fire protection, the chemical and oil industries, fuel handling systems, and also for applications within the power generation industry.

With the introduction of the double and triple eccentric designs, butterfly valves are more and more used also in the oil and gas industry and have started to compete with more traditional valves, such as globe and ball valves.

BUTTERFLY VALVES PARTS

Butterfly valves are comprised of several key components that allow them to effectively control fluid flow. Each part plays a crucial role in the valve’s operation, durability, and ability to provide a tight seal.

Here are the main components of a butterfly valve:

1. Body

The outer casing of the valve holds all internal components together and connects the valve to the piping system. The body material varies depending on the application and can include cast iron, stainless steel, PVC, and others.

2. Disc

The circular element that pivots within the flow stream to open or close the valve. The disc’s rotation controls the flow through the valve. Materials for the disc often match or are compatible with the body material and are selected based on the fluid’s properties.

3. Stem

The shaft that connects the disc to the actuator or handle outside the valve body. The stem can be one-piece with the disc or two-piece, where the disc is mounted between two stems. Stems are typically made from stainless steel or other corrosion-resistant materials.

4. Seat

The sealing surface against which the disc closes. The seat can be integral to the valve body or a replaceable component. It is made from materials like rubber, PTFE, or metal, depending on the application’s sealing requirements and the fluid’s characteristics.

5. Actuator

The mechanism used to rotate the disc. Actuators can be manual (handles or gears) or automatic (pneumatic, hydraulic, or electric). The choice of actuator depends on the valve size, required control level, and operational environment.

6. Handle Or Hand Lever

For manual operation, a handle or lever is attached to the stem, allowing the operator to rotate the disc. It usually includes a locking mechanism to secure the valve in the open or closed position.

7. Gearbox

In larger butterfly valves or in applications requiring precise control, a gearbox is used in conjunction with the hand lever or actuator to facilitate easier operation by reducing the effort needed to turn the valve.

8. Bushings

Located between the stem and the body or between the stem and the disc, bushings reduce friction and wear during operation, contributing to the valve’s smooth operation and longevity.

9. Packing

A seal around the stem to prevent fluid from leaking out of the valve body along the stem. Packing materials vary but often include PTFE or graphite, chosen for their sealing properties and resistance to the process fluid.

10. Flanges Or Ends

Butterfly valves can have different end configurations to connect to the piping system, including wafer, lug, flanged, or butt-weld ends. The selection depends on the piping system design and the requirements for disassembly and maintenance.

Each component of a butterfly valve is critical to its performance, affecting everything from how well the valve seals to how easily it can be operated and maintained. Selecting the right materials and design for these components is essential to ensure the valve meets the application’s demands.

HOW BUTTERFLY VALVES FUNCTION

A butterfly valve functions by using a rotating disc to control the flow of fluid through a pipe. The disc, which is the main component of the valve, is connected to an actuator or a manual handle at the top of the valve.

Here’s a step-by-step explanation of how a butterfly valve operates:

1. Open Position

When the valve is fully open, the disc is rotated so that it lies parallel to the flow direction, allowing fluid to pass through with minimal obstruction. The handle or actuator is typically aligned parallel to the pipe in this position, indicating that the valve is open.

2. Closing The Valve

To close the valve, the handle or actuator is turned, which rotates the disc. As the disc rotates towards a perpendicular position relative to the flow path, it begins to block the flow of fluid through the pipe.

3. Closed Position

When the disc is rotated to a position perpendicular to the flow direction, it fully obstructs the pipe, stopping the flow entirely. In this position, the handle or actuator is aligned perpendicular to the pipe, indicating that the valve is closed.

4. Controlling Flow

Butterfly valves can also be used to regulate the flow of fluid through the pipe by adjusting the disc’s angle. By partially opening or closing the valve (i.e., positioning the disc at various angles between fully open and fully closed), the operator can control the flow rate through the valve. This throttling capability allows for the precise adjustment of flow, although it’s important to note that butterfly valves may not provide as fine control as some other valve types designed specifically for flow regulation.

5. Actuation

Butterfly valves can be operated manually or automated with actuators. Manual operation is common for smaller valves or in applications where precise control is not critical. For larger valves or where remote control and precise adjustments are necessary, pneumatic, electric, or hydraulic actuators are used.

Key Features

Compact and Lightweight: Butterfly valves have a simple, compact design, making them easy to install and requiring less space compared to other valve types, like gate or globe valves.
Quick Operation: The quarter-turn operation of butterfly valves allows for rapid opening and closing, which is beneficial in emergency situations or applications requiring frequent operation.
Versatility: Suitable for a wide range of applications, handling liquids, gases, and semi-solids in various industries, including water treatment, chemical processing, HVAC, and more.

Again, it is important to understand that the key component of a butterfly valve is the disc, a metal ring that is positioned at the centerline of the pipe and connected to an external actuator (manual level or actuator) via a rod.

The functionality of a butterfly valve revolves around the rotation of such disc to open, close, or throttle the flow of fluid in a piping system. In the closed position, the disc blocks the bore of the valve, and, in an open position, the disc allows the passage of the fluid.

A quarter-turn movement is needed to switch the valve from a fully open to a fully closed position (and such movement can be executed as quickly as for ball valves).

This design offers a balance of simplicity, efficiency, and versatility, making butterfly valves a popular choice for many fluid control applications.

Compared to a ball valve, the disc of a butterfly valve is always in contact with the fluid conveyed by the pipeline and creates, therefore, a pressure drop.

PRESSURE DROP IN BUTTERFLY VALVES

The pressure drop across a butterfly valve, like other control valves, is an essential factor to consider in system design and valve selection. Pressure drop refers to the reduction in pressure as fluid passes through a valve, a phenomenon that occurs due to friction and flow resistance introduced by the valve’s presence in the flow path.

Factors Affecting Pressure Drop In Butterfly Valves

Valve Design: The inherent design of butterfly valves, which includes a disc that pivots within the flow stream, inherently introduces some level of flow resistance. The size of the valve (relative to the pipe diameter), the disc shape, and the seat design can influence the extent of this resistance.
Disc Position: The pressure drop is significantly influenced by the disc’s position. When fully open (parallel to the flow direction), the pressure drop is minimal. However, as the disc begins to close (rotating towards a perpendicular position to the flow), it increasingly obstructs the flow path, leading to a higher pressure drop.
Flow Rate: The rate at which fluid flows through the valve directly affects the pressure drop; higher flow rates generally result in higher pressure drops due to increased friction and turbulence around the disc and within the valve body.
Fluid Properties: The type of fluid (its density and viscosity) also impacts the pressure drop. More viscous fluids tend to create higher pressure drops compared to less viscous ones under the same conditions.

Calculating Pressure Drop

The pressure drop across a butterfly valve can be calculated using various formulas and coefficients that account for the factors mentioned above. One common method involves using the valve’s flow coefficient (Cv) for a given valve opening position. The Cv value represents the flow rate of water (in US gallons per minute) at a temperature of 60°F that will flow through the valve with a pressure drop of 1 psi.

The general formula to estimate the pressure drop ( $Δ P$ ) in psi is:

Q^2 /

Where Q is the flow rate through the valve in US gallons per minute (GPM), and Cv is the flow coefficient of the valve at the specific opening position.

Considerations For System Design

Selection: Choose a valve size and type that minimizes the pressure drop consistent with the application’s requirements. Full-port (or full-bore) butterfly valves generally offer lower pressure drops.
Operation: Understand that frequent operation near the closed position increases the pressure drop and can impact pump performance and energy consumption.
Application: In applications sensitive to pressure drop, consider the valve’s impact on the overall system and evaluate if an alternative valve type or size might be more appropriate.

In summary, while butterfly valves are favored for their compact design and quick operation, their influence on system pressure must be considered, especially in applications where maintaining pressure is critical. Proper valve selection and system design can help manage pressure drops to acceptable levels.

BUTTERFLY VALVE SPECIFICATIONS (ASME/API)

The American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME) provide standards and specifications that cover various aspects of butterfly valves, including design, materials, testing, and performance requirements. These standards ensure that butterfly valves meet certain criteria for safety, reliability, and interoperability in different industrial applications. Here are some of the key API and ASME specifications relevant to butterfly valves:

API Standards

API 609: Butterfly Valves: Double-flanged, Lug- and Wafer-type

This specification covers design, materials, face-to-face dimensions, pressure-temperature ratings, and testing requirements for butterfly valves with double-flanged, lug, and wafer-type configurations. It’s applicable for valves intended for general-purpose, isolation, and control applications in piping systems.

ASME Standards

ASME B16.34: Valves – Flanged, Threaded, and Welding End
Although primarily known for gate, globe, and check valves, ASME B16.34 also includes general valve design criteria that can apply to butterfly valves, such as pressure-temperature ratings, shell material categories, and testing requirements.
ASME B16.5: Pipe Flanges and Flanged Fittings
This standard covers dimensions and ratings for flanges that can be used with butterfly valves, ensuring compatibility with piping systems.
ASME B16.47: Large Diameter Steel Flanges
Similar to ASME B16.5 but focuses on larger diameter flanges, which might be relevant for larger butterfly valve applications.
ASME B16.10: Face-to-Face and End-to-End Dimensions of Valves
Provides the standard face-to-face and end-to-end dimensions for butterfly valves, facilitating proper integration and replacement in piping systems.

Other Relevant Standards

ISO 5211: Industrial valves — Part-turn actuator attachments
This international standard, often referenced alongside API and ASME standards, specifies the requirements for the attachment of part-turn actuators to industrial valves, including butterfly valves. It’s crucial to ensure that actuators and valves are compatible and can be securely attached to each other.
MSS SP-67: Butterfly Valves
Issued by the Manufacturers Standardization Society (MSS), this standard covers detailed requirements for butterfly valves, including design, dimensions, pressure rating, and testing. It’s widely recognized and used alongside API and ASME standards.
MSS SP-68: High-Pressure Butterfly Valves with Offset Design
MSS focuses on high-pressure butterfly valves with an offset design, providing criteria for pressure integrity and performance.

These API and ASME standards, along with other relevant specifications, guide manufacturers and users of butterfly valves in ensuring quality, safety, and efficiency in their operations. Compliance with these standards is often a requirement in industrial projects, especially those involving critical applications in the oil & gas, chemical, water treatment, and power generation sectors.

TYPES OF BUTTERFLY VALVES

Butterfly valves are categorized based on their design, sealing mechanism, and application requirements. The various types offer distinct advantages and are suited to specific operational environments.

Here are the primary types of butterfly valves:

1. Concentric (Zero Offset) Butterfly Valves

Design: Features a disc centered directly in the middle of the valve body, with the stem passing through the disc center. The seat is typically made of a resilient material such as rubber or Teflon.
Application: Best suited for lower pressure and temperature applications. The simple design is effective for water, air, and other non-corrosive media.

The concentric type of butterfly valve is typically used in water (treatment, transmission, and distribution) and clean wastewater treatment plants, fire protection systems (indoor/outdoor), and gas supply (natural and flare gas).

Moreover, these types of butterfly valves may also be found in the following types of installations:

Pumping installations
HVAC
Aeration systems
Filter Installations
Pumping installations
Membrane installations
2. Double Offset (High-Performance) Butterfly Valves
- Design: Also known as high-performance butterfly valves, they have two offsets. The first offset is to the side of the pipe centerline, while the second offset moves the shaft behind the disc plane. This design minimizes seat wear and allows for tighter sealing.
- Application: Ideal for higher pressure and temperature conditions, handling a wider range of fluids, including corrosive and abrasive types.
Double eccentric butterfly valves find application in underground water supply systems and compete with gate valves (especially in larger bore sizes) because they are lighter, cheaper, and minimize the excavation works.

Double and triple-offset butterfly valves are also denominated “eccentric”. The main differences between the concentric and eccentric types of butterfly valves can be summarized as follows:
- Concentric butterfly valve: the stem is centered in the middle of the disc and the is disc centered in the bore
- Eccentric butterfly valve (double offset and triple offset): has one or more stub shafts (stems) which are located in an offset position from the center of the valve. Eccentric butterfly valves are also defined as the double or the triple offset.
A concentric butterfly valve (left), a double offset butterfly valve (center), triple offset butterfly valve (right)

3. Triple Offset Butterfly Valves
- Design: Features three offsets, with the third being the geometrical shape of the seating surface (conical shape). This design eliminates friction between the seat and the disc during operation and allows for metal-to-metal sealing.
- Application: Suitable for extreme pressure and temperature applications, including steam, oil, and gas services. It provides reliable performance in demanding conditions.
Triple-offset butterfly valves are generally manufactured in high-grade materials like stainless steel and duplex/super duplex steel and compete with ball valves in mission-critical applications with remarkable corrosion and high temperature/pressure.

Triple-offset butterfly valves are the most sophisticated type and have gained market share in recent years, due to the dramatic performance improvement achieved by specialized manufacturers.

4. Lugged Butterfly Valves
- Design: The valve body has lugs (extensions with bolt holes) that allow it to be bolted directly to the pipe flanges. This provides a secure and rigid connection and allows for easy removal of downstream piping without affecting the upstream side.
- Application: Used in applications where the valve must be easily removed for maintenance or where the system requires dead-end service capability.
5. Wafer Butterfly Valves
- Design: Designed to fit between two pipe flanges (the wafer shape), these valves are held in place by the bolts that connect the flanges. They are compact and cost-effective but not suitable for end-of-line service where removal is necessary.
- Application: Commonly used in systems where space is limited and in applications that do not require disassembly of the pipe system for valve maintenance.
- 6. Rubber-Lined Butterfly Valves
  - Design: Features a body and disc lined with rubber or another elastomeric material, providing enhanced corrosion resistance and a tight seal.
  - Application: Ideal for handling corrosive fluids, slurries, and other abrasive media in water treatment, chemical processing, and similar industries.
  7. Metal-Seated Butterfly Valves
  - Design: Constructed with metal seats, these valves are designed to withstand higher temperatures and more abrasive conditions than their rubber-lined counterparts.
  - Application: Suitable for high-temperature applications, such as steam services, and where higher durability is required.
  Each type of butterfly valve offers unique features and benefits, making them suitable for a broad range of applications. Selecting the right type depends on factors such as the nature of the fluid, operating pressure and temperature, and specific system requirements.
  
  A key first classification is between concentric or eccentric butterfly valves:
  
  DIFFERENCES BETWEEN DOUBLE VS. TRIPLE ECCENTRIC BUTTERFLY VALVE
  
  Double and triple eccentric butterfly valves are both designed to offer improved performance over traditional concentric butterfly valves, especially in high-pressure and high-temperature applications. The terms “double” and “triple” refer to the number of offsets (eccentricities) in the valve design, which significantly affect how the valve operates and seals. Understanding the differences between these two types of eccentric butterfly valves is crucial for selecting the right valve for specific operational needs.
  
  Double Eccentric Butterfly Valves (Double Offset)
  - Design: The first offset is the shaft placement off the pipe or disc centerline, which allows the disc to move off the seat upon opening, reducing wear on the sealing surface. The second offset is the shaft placement behind the disc plane, creating a cam action during operation that enhances sealing capability and reduces operating torque.
  - Sealing: Typically utilizes a resilient (soft) seat, which can be made of materials like PTFE, rubber, or other polymers, allowing for tight shut-off in various applications.
  - Applications: Suitable for higher pressure and temperature applications than concentric valves but below the extreme conditions that triple offset valves are designed for. Commonly used in water distribution, HVAC systems, light industrial processes, and chemical applications where a tight seal and durability are required.
  Triple Eccentric Butterfly Valves (Triple Offset)
  - Design: Incorporates three offsets: two similar to the double eccentric design and a third offset, which involves angling the conical shape of the seating surface. This geometry ensures that the disc only contacts the seat at the final point of closure, minimizing wear and allowing for a metal-to-metal seal.
  - Sealing: The metal-to-metal seat design enables the triple offset valve to handle extreme temperatures, pressures, and corrosive media, providing a long-lasting, bubble-tight seal.
  - Applications: Engineered for the most demanding applications, including high-pressure steam, oil and gas pipelines, power generation, and process industries where reliability and performance under extreme conditions are paramount.
  Key Differences (Double/Triple Eccentric Types)
  - Sealing Mechanism: Double eccentric valves usually have resilient seats for good sealing at lower pressures and temperatures, while triple eccentric valves use a metal-to-metal seat design for harsh conditions.
  - Wear and Tear: Triple offset valves minimize wear on the sealing surfaces due to the disc only making contact at full closure, unlike double offset valves, which may experience more wear due to their soft sealing materials.
  - Application Suitability: Double offset valves are versatile for a wide range of applications but might not be suitable for the highest pressures and temperatures. Triple offset valves are designed for extreme conditions where performance and durability are critical.
  In summary, the choice between double and triple eccentric butterfly valves depends on the specific application requirements, including pressure, temperature, and the nature of the media being handled. Triple offset valves are typically chosen for their ability to perform in extreme conditions, offering durability and a reliable seal, whereas double offset valves provide an efficient and cost-effective solution for a broad range of less severe applications.
  
  .
  
  The images show the design difference between a double and a triple eccentric butterfly valve (respectively at the left and right side of the diagram).
  MATERIALS FOR BUTTERFLY VALVES
  
  VALVE BODY
  
  Butterfly valves, like any other type of valve, are available in multiple material grades and combinations of materials (body, disc, seat).
  
  The selection of the materials is based on the fluid to be shut off, the pressure, and the temperature of the application at hand.
  
  The body material of a butterfly valve is a critical factor that determines its suitability for specific applications, especially considering the fluid it will handle, the operating environment, pressure, and temperature conditions. Various materials are used for butterfly valve bodies, each offering different properties in terms of strength, corrosion resistance, and cost.
  
  Here is a list of the main materials used for butterfly valve bodies, which are generally cast grades.
  
  CAST IRON
  - Properties: Good mechanical strength, excellent vibration and shock resistance, and cost-effectiveness.
  - Applications: Widely used in water and wastewater treatment, air conditioning systems, and other low to medium-pressure applications.
  DUCTILE IRON
  - Properties: Higher strength and ductility compared to cast iron, with good corrosion resistance.
  - Applications: Suitable for higher pressure applications than cast iron, including water distribution, gas supply, and some industrial processes.
  Note that cast iron and ductile iron are the cast materials preferred for butterfly valves used in water treatment, distribution, and transmission.
  CARBON STEEL
  
  Carbon steel is the most common material for body and disc in oil & gas applications:
  - Properties: High strength and durability, with good resistance to high pressure and temperature.
  - Applications: Used in oil and gas, power generation, and other industrial applications where high-pressure and temperature resistance is required.
  The most common grades used for butterfly valve bodies and discs are ASTM A216 WCB and LCC (Low Carbon Content), which are both cast types. They are used, respectively, for high-temperature and low-temperature service.
  
  The main advantage of carbon steel (CS) butterfly valves is their relatively low cost combined with acceptable performance (especially for low-pressure applications). The weakness of carbon steel valves is their poor resistance to corrosion (which can be improved by applying external paints or internal lining materials such as Teflon)
  
  STAINLESS STEEL
  
  Stainless steel butterfly valves are widely utilized across various industries for their durability, corrosion resistance, and suitability for handling a broad range of fluids, including corrosive substances, water, steam, and gas. Constructed from stainless steel for both the body and the disc, these valves offer several advantages and are chosen for specific applications based on their material properties.
  
  Advantages Of Stainless Steel Butterfly Valves
  - Corrosion Resistance: Stainless steel offers excellent resistance to corrosion caused by various chemicals and environmental conditions. This makes it ideal for applications in chemical processing, pharmaceuticals, and food and beverage industries, where maintaining purity is critical.
  - High Strength and Durability: Provides strength and durability under high-pressure conditions, ensuring a long service life even in demanding applications.
  - Temperature Resistance: Capable of withstanding both high and low temperatures, making them suitable for applications involving steam, hot fluids, or cold water systems.
  - Hygienic Properties: The smooth, non-porous surface of stainless steel is easy to clean and disinfect, which is essential for sanitary applications in the food, beverage, and pharmaceutical industries.
  - Aesthetic Appearance: Stainless steel has a clean and modern appearance, which is often preferred in visible installations.
  Common Grades Of Stainless Steel For Butterfly Valves
  - 304 Stainless Steel: Offers good corrosion resistance and is widely used in general applications that do not involve exposure to corrosive chemicals and extreme temperatures.
  - 316 Stainless Steel: Contains molybdenum, which enhances its corrosion resistance, especially against chlorides and other industrial solvents. It is preferred for more corrosive environments, such as seawater and chemical processing.
  - 316L Stainless Steel: A low-carbon variant of 316, it has reduced carbon content that minimizes carbide precipitation during welding, improving corrosion resistance in welded joints.
  Applications
  
  Stainless steel butterfly valves are chosen for their robust performance in various settings, including:
  - Chemical Processing: For controlling the flow of aggressive chemicals, acids, and solvents.
  - Food and Beverage Production: In systems requiring strict hygiene standards and resistance to food acids and cleaning agents.
  - Pharmaceutical Manufacturing: Where cleanliness and contamination prevention are paramount.
  - Water Treatment and Distribution: Suitable for handling both clean and wastewater, as well as desalination processes.
  - Oil and Gas Industry: For applications requiring resistance to corrosion from saltwater, chemicals, and high-pressure conditions.
  Selection Considerations
  
  When selecting a stainless steel butterfly valve, it’s crucial to consider:
  - Type of Fluid: Ensure compatibility with the fluid’s properties, including corrosiveness, temperature, and cleanliness requirements.
  - Pressure and Temperature Ratings: Choose a valve that can withstand the system’s operating pressure and temperature range.
  - Connection Type: Consider the valve’s connection type (wafer, lug, flanged) for compatibility with the piping system.
  - Actuation Method: Determine whether manual, pneumatic, electric, or hydraulic actuation is best suited for the application’s operational needs.
  In summary, stainless steel butterfly valves offer a reliable and efficient solution for flow control in a wide range of industrial applications. Their corrosion resistance, strength, and temperature tolerance make them a versatile choice for many fluid handling systems.
  
  DUPLEX & SUPERDUPLEX STEEL
  
  Butterfly valves made from duplex and super duplex stainless steels are engineered for applications requiring exceptional strength and corrosion resistance, especially in harsh and aggressive environments. Duplex stainless steels combine the properties of austenitic and ferritic stainless steels, resulting in materials that offer both high strength and excellent resistance to corrosion, including stress corrosion cracking. Super duplex stainless steels provide even higher corrosion resistance and strength, making them suitable for more demanding applications.
  
  Characteristics Of Duplex And Super Duplex Stainless Steel Butterfly Valves
  - High Strength: Duplex and super duplex stainless steels have higher strength compared to austenitic stainless steels, allowing for the design of thinner valve bodies and components without compromising integrity.
  - Superior Corrosion Resistance: These materials are highly resistant to a wide range of corrosive environments, including those containing chlorides, making them ideal for use in marine, chemical processing, and oil & gas applications.
  - Good Fatigue Resistance: The combination of strength and corrosion resistance makes duplex and super duplex valves highly resistant to fatigue, extending their service life under cyclic loading conditions.
  - Resistance to Stress Corrosion Cracking: Particularly in chloride-containing environments, duplex, and super duplex steels exhibit superior resistance to stress corrosion cracking, a common issue for standard austenitic stainless steels in certain conditions.
  Common Grades
  - Duplex Stainless Steel (UNS S31803, S32205): Features a balanced microstructure of austenite and ferrite, offering good resistance to pitting and crevice corrosion, high strength, and good weldability.
  - Super Duplex Stainless Steel (UNS S32750, S32760): Contains higher levels of chromium, molybdenum, and nitrogen, providing even greater resistance to corrosion and increased strength compared to duplex stainless steel.
  Applications
  
  Butterfly valves constructed from duplex and super duplex stainless steels are particularly suited for:
  - Offshore Oil and Gas Operations: In environments exposed to seawater, sour gas, and other corrosive substances.
  - Chemical Processing: For handling aggressive chemicals, especially where chloride-induced corrosion is a concern.
  - Desalination Plants: Where valves are exposed to highly corrosive seawater.
  - Marine Applications: Including shipping and coastal facilities, where saltwater corrosion is an ongoing challenge.
  - Pulp and Paper Industry: For processes involving corrosive chemicals used in paper production.
  Selection Considerations
  
  When choosing duplex or super duplex stainless steel butterfly valves, factors to consider include:
  - Corrosion Resistance Needs: Assess the specific corrosive elements present in the application environment to select the most appropriate material grade.
  - Pressure and Temperature Requirements: Ensure the selected valve can withstand the operating pressures and temperatures of the system.
  - Cost-Effectiveness: While duplex and super duplex steels offer superior properties, they also come at a higher cost compared to standard stainless steels. Evaluate the long-term benefits of their use in reducing maintenance and replacement costs.
  - Weldability and Fabrication: Consider the welding and fabrication requirements, as duplex and super duplex materials may require specific techniques and precautions during manufacturing and installation.
  In summary, butterfly valves made from duplex and super duplex stainless steels provide a robust solution for controlling flow in environments where corrosion resistance and mechanical strength are critical. Their superior properties make them an excellent choice for demanding industrial applications where conventional stainless steels might not suffice.
  
  NICKEL ALLOY STEEL
  
  Butterfly valves made from nickel alloys are designed for the most demanding applications, offering exceptional resistance to corrosion, heat, and pressure. Nickel alloys, such as Inconel, Hastelloy, Monel, and Nickel 200/201, are renowned for their ability to withstand extreme environments, making them ideal for critical and high-performance applications across various industries.
  
  Characteristics
  - Corrosion Resistance: Nickel alloys provide excellent resistance to a wide range of corrosive environments, including seawater, chlorine, and acidic or alkaline substances. They are particularly effective against corrosion that challenges other materials, such as stress-corrosion cracking.
  - High-Temperature Performance: These alloys maintain their strength and resistance even at very high temperatures, making them suitable for applications involving heat.
  - Durability: The inherent strength and corrosion resistance of nickel alloys ensure that butterfly valves made from these materials have a long service life, even in harsh conditions.
  Common Nickel Alloys Used For Butterfly Valves
  - Inconel (e.g., Inconel 625, Inconel 718): Known for high strength and excellent corrosion resistance, especially in high-temperature environments.
  - Hastelloy (e.g., Hastelloy C-276, Hastelloy C-22): Offers outstanding resistance to strong oxidizing agents and is used in severe corrosive environments.
  - Monel (e.g., Monel 400, Monel K-500): Exhibits excellent resistance to seawater and caustic environments, combining good corrosion resistance with high strength.
  - Nickel 200/201: Pure nickel or nearly pure nickel, providing excellent resistance to corrosion by alkaline substances and good thermal, electrical, and magnetostrictive properties.
  Applications
  
  Nickel alloy butterfly valves are used in situations where conventional materials would fail, including:
  - Chemical Processing: For handling aggressive chemicals, solvents, and gases that require superior corrosion resistance.
  - Oil and Gas Industry: Especially in sour gas applications where hydrogen sulfide can cause sulfide stress cracking in other materials.
  - Power Generation: In applications involving high temperatures or corrosive gases.
  - Marine and Offshore: For seawater systems and environments exposed to marine atmospheres, where corrosion resistance is critical.
  - Pharmaceuticals: In processes requiring clean, non-contaminating materials.
  Selection Considerations
  
  When choosing nickel alloy butterfly valves, consider:
  - Specific Corrosion Resistance Needs: Match the alloy to the particular corrosive agents present in the process or environment.
  - Temperature Range: Ensure the chosen alloy can withstand the operational temperature extremes.
  - Pressure Ratings: Verify that the valve can handle the system’s pressure requirements without compromising its integrity or performance.
  - Cost-Effectiveness: Nickel alloys tend to be more expensive than other materials, so consider the long-term benefits of reduced maintenance and replacement costs against the initial investment.
  Nickel alloy butterfly valves represent a high-end solution for controlling flow in applications where extreme conditions would compromise lesser materials. Their use can significantly enhance system reliability, safety, and longevity, albeit at a higher initial cost. The choice of a specific nickel alloy should be based on a thorough analysis of the application’s requirements, including exposure to corrosive substances, temperature, and pressure conditions.
  
  TITANIUM AND TITANIUM ALLOYS
  
  Butterfly valves made from titanium are renowned for their exceptional strength-to-weight ratio, outstanding corrosion resistance, and excellent durability under challenging conditions. Titanium and its alloys are lightweight yet offer mechanical properties comparable to those of some steel grades, making them an excellent choice for butterfly valves in specific applications.
  
  Characteristics
  - Corrosion Resistance: Titanium is exceptionally resistant to corrosion by seawater, chlorides, and many acidic environments, making it suitable for applications where other materials might fail.
  - Strength and Durability: Despite being lightweight, titanium maintains high strength and withstands extreme pressures and temperatures, contributing to the longevity of the valve.
  - Non-Magnetic and Biocompatible: Titanium is non-magnetic and biocompatible, expanding its use to applications where magnetic interference is a concern or where it contacts biological materials.
  - Temperature Resistance: Titanium valves can operate effectively across a broad temperature range, maintaining their integrity in both low and high-temperature environments.
  Applications
  
  Titanium butterfly valves are ideal for industries and applications that demand material properties beyond what conventional metals can provide, including:
  - Chemical Processing: For handling highly corrosive substances, such as chlorine and acids, where titanium’s corrosion resistance ensures reliability and safety.
  - Seawater and Desalination: In seawater desalination plants, offshore platforms, and marine applications, where the resistance to seawater corrosion is critical.
  - Pharmaceutical and Food Processing: Where the non-toxic and biocompatible nature of titanium is essential for avoiding contamination.
  - Aerospace and High-Performance Engineering: In applications requiring materials that can withstand high temperatures and pressures without significant weight penalties.
  Selection Considerations
  
  When selecting titanium butterfly valves, consider the following factors:
  - Grade of Titanium: Various grades of titanium offer different properties. For example, Grade 2 titanium is commercially pure and widely used for general corrosion resistance, while Grade 5 (Ti-6Al-4V) is an alloy known for its higher strength and used in more demanding applications.
  - Cost: Titanium is more expensive than many other materials due to its processing complexity and raw material costs. Consider the long-term benefits of reduced maintenance and longer service life against the initial investment.
  - Compatibility: Ensure the specific grade of titanium chosen is compatible with the fluid media, operating conditions, and environmental exposure of the application.
  - Fabrication and Repair: Consider the availability of resources for fabrication and repair, as working with titanium requires specific expertise and equipment.
  Titanium butterfly valves represent a high-end solution for controlling flow in demanding applications where conventional materials are inadequate. Their selection is justified in environments that require exceptional corrosion resistance, strength, and durability, despite their higher initial cost. The benefits of using titanium include extended equipment life, reduced maintenance, and improved safety and reliability in critical applications.
  
  ALUMINIUM
  - Properties: Lightweight, good corrosion resistance, and ease of machining.
  - Applications: Primarily used in low-pressure applications, such as air handling, vacuum services, and dry bulk handling.
  BRONZE
  - Properties: Good corrosion resistance, especially against seawater and other saline solutions.
  - Applications: Used in marine, desalination, and certain chemical processing applications where corrosion resistance is paramount.
  NICKEL ALUMINIUM BRONZE
  
  This is a copper alloy that contains approximately 10% aluminum, 5% nickel, and 5% iron. It features strong corrosion resistance, especially in seawater applications, and resists the formation of a biofilm, a frequent cause of corrosion problems for stainless steels.
  
  Butterfly valves API 609 may have soft or metal seats. Valves with soft seats are also called “soft-seated” or “resilient” butterfly valves and are of the centric type. Eccentric designs (double or triple offset) are available, generally, with metal seat designs, which could also be fireproof.
  
  For less critical applications, butterfly valves are also available in plastic-grade materials, such as PVC, CVPC, Polypropylene (PP), and Polyethylene (PE). Here are the main features of plastic butterfly valves:
  
  PVC
  - Properties: Excellent corrosion resistance to a wide range of chemicals, lightweight, and cost-effective.
  - Applications: Suitable for low-pressure applications, including water treatment, chemical processing, and irrigation systems.
  CPVC
  - Properties: Similar to PVC but can withstand higher temperatures.
  - Applications: Used in hot water distribution, and chemical processing where higher temperature resistance than PVC is needed.
  PP/PE
  - Properties: Excellent chemical and corrosion resistance, lightweight, and suitable for a wide range of temperatures.
  - Applications: Chemical processing, water treatment, and applications involving aggressive or corrosive fluids.
  VALVE SEAT
  
  SOFT SEATED BUTTERFLY VALVE (“RESILIENT”)
  
  Soft-seated butterfly valves are designed to provide a tight seal and are typically used in applications where the sealing of gases or liquids is critical and where the operating conditions are within moderate temperature and pressure ranges. The “soft seat” refers to the use of elastomeric or other non-metallic, resilient materials for the sealing mechanism between the disc and the valve body, enhancing the valve’s ability to create a tight shut-off.
  
  Key Features
  - Sealing Material: The soft seat is usually made from materials such as PTFE (Polytetrafluoroethylene), NBR (Nitrile Butadiene Rubber), EPDM (Ethylene Propylene Diene Monomer), or Viton (a type of fluoroelastomer). Each material offers different properties in terms of chemical resistance, temperature tolerance, and wear characteristics, making them suitable for various applications.
  - Tight Shut-Off: Soft-seated butterfly valves are known for their excellent sealing capabilities, providing a near bubble-tight closure. This makes them ideal for applications requiring precise control over the flow and leakage prevention.
  - Low Torque Operation: The soft seating material reduces the friction between the disc and the seat, allowing for easy operation with minimal torque requirements.
  - Application Versatility: These valves are used in a wide range of applications, from water and wastewater treatment to chemical processing, food and beverage, and HVAC systems, handling a variety of fluids, including corrosive and abrasive media.
  Applications
  
  Soft-seated butterfly valves are versatile and can be employed in various industrial and commercial applications, including:
  - Water and Wastewater: For controlling and regulating water flow in treatment plants, distribution systems, and irrigation.
  - Chemical Processing: Handling mild to moderately corrosive fluids, depending on the seat material’s chemical compatibility.
  - Food and Beverage: In processes requiring sanitary conditions, where non-toxic and cleanable sealing materials like PTFE are essential.
  - Air and Gas Handling: For applications involving air, natural gas, and other gases where a tight seal is crucial to prevent leakage.
  Considerations
  
  While soft-seated butterfly valves offer many advantages, there are considerations to keep in mind when selecting them for specific applications:
  - Temperature Limits: The elastomeric and plastic materials used for the seats have upper temperature limits, beyond which they may degrade or lose their sealing properties.
  - Chemical Compatibility: It’s essential to ensure that the seat material is compatible with the process fluid to prevent damage and ensure long-term reliability.
  - Wear and Tear: While soft seats provide excellent sealing, they may be more prone to wear and damage from abrasive media than metal-seated valves.
  In summary, soft-seated butterfly valves offer excellent sealing capabilities and are suitable for a wide range of applications requiring precise flow control and tight shut-off. Selecting the appropriate seat material based on the application’s specific requirements is crucial for optimal performance and longevity.
  
  Soft seated butterfly valves (resilient) feature EPDM, VITON, NBR, BUNA-N, and similar soft seats. Soft-seat butterfly valves are generally of the concentric type and suit low-pressure and non-critical applications
  
  METAL SEATED BUTTERFLY VALVE
  
  Metal-seated butterfly valves are designed for more demanding applications where high temperatures, higher pressures, and abrasive or corrosive media are present. Unlike soft-seated valves, which use elastomeric materials for sealing, metal-seated valves rely on metal-to-metal contact between the disc and the seat, providing durability and resistance in harsh conditions.
  
  Key Features
  - Durability: Metal seats are highly durable and resistant to wear, making them suitable for applications involving abrasive particles or high-velocity flows that could damage softer seat materials.
  - High Temperature and Pressure Resistance: Metal-seated butterfly valves can withstand higher temperatures and pressures than their soft-seated counterparts, making them ideal for industrial processes involving steam, hot gases, or high-pressure fluids.
  - Corrosion Resistance: Depending on the metals used (such as stainless steel, Hastelloy, Inconel, or others), these valves offer excellent resistance to corrosion and chemical attack.
  - Leakage: Metal-seated valves may not provide the same level of tight shut-off as soft-seated valves. They are generally designed to meet industry standards for acceptable leakage rates under specific conditions, which is often sufficient for many high-temperature and high-pressure applications.
  Materials For Metal Seats
  The choice of materials for metal seats in butterfly valves is critical for ensuring the valve’s durability, performance, and resistance to the operating environment’s conditions, such as temperature, pressure, and corrosion. Here are some commonly used materials for metal seats in butterfly valves, along with their characteristics and applications:
  
  1. Stainless Steel
  
  Characteristics: Stainless steel offers excellent corrosion resistance, strength, and temperature resistance. Common grades used include 304, 316, and 316L, with 316/316L being preferred for better corrosion resistance due to their molybdenum content.
  
  Applications: Widely used in water and wastewater treatment, food and beverage processing, and chemical industries where corrosion resistance is essential.
  
  2. Carbon Steel
  
  Characteristics: Carbon steel provides good strength and thermal properties at a lower cost than stainless steel but is more susceptible to corrosion. It is often protected with coatings or treatments.
  
  Applications: Suitable for applications where corrosion is not a significant concern, such as in certain oil and gas or power generation processes.
  
  3. Alloy Steel
  
  Characteristics: Alloy steels, such as Chrome-Moly (e.g., A182 F22), are used for their enhanced strength, durability, and resistance to high temperatures and pressures.
  
  Applications: Ideal for high-temperature and high-pressure applications, including steam service, boiler feed water, and thermal oil systems.
  
  4. Titanium
  
  Characteristics: Titanium and its alloys offer exceptional corrosion resistance, especially to chlorides, along with high strength-to-weight ratios and excellent temperature tolerance.
  
  Applications: Used in seawater, brine, and other corrosive environments, including chemical processing, desalination, and marine applications.
  
  5. Hastelloy
  
  Characteristics: Hastelloy alloys are nickel-based and known for their outstanding resistance to severe corrosive environments, including strong acids.
  
  Applications: Suitable for aggressive chemical applications, such as handling sulfuric acid, hydrochloric acid, and chlorine.
  
  6. Inconel
  
  Characteristics: Inconel alloys are nickel-chromium-based and are known for their ability to withstand extreme temperatures, oxidation, and corrosion.
  
  Applications: Used in high-temperature applications, such as heat treating equipment, gas turbine components, and nuclear reactors.
  
  7. Monel
  
  Characteristics: Monel alloys are nickel-copper-based and offer excellent corrosion resistance, especially to saltwater and acidic conditions.
  
  Applications: Ideal for marine, chemical, and hydrocarbon processing where high corrosion resistance is required.
  
  8. Bronze
  
  Characteristics: Bronze, particularly aluminum bronze, provides good corrosion resistance, especially against seawater and other mildly corrosive environments.
  
  Applications: Commonly used in water, gas, and some chemical applications where its corrosion resistance and strength are beneficial.
  
  The selection of metal seat material for a butterfly valve depends on the specific requirements of the application, including the type of medium being handled, operating temperatures and pressures, and the presence of corrosive substances. Matching the seat material to these conditions ensures optimal performance, durability, and reliability of the valve in its operational environment.
  
  Special treatments and coatings for butterfly valve seats enhance their performance, durability, and suitability for specific applications, especially in challenging environments. These treatments can improve the seat’s resistance to wear, corrosion, temperature, and chemical attack, extending the valve’s service life and reliability. Here are some common treatments and materials used for enhancing butterfly valve seats:1. Polytetrafluoroethylene (PTFE) Coating
  
  Characteristics: PTFE, or Teflon, offers excellent chemical resistance and a low coefficient of friction, minimizing wear on the seat.
  
  Applications: Suitable for chemical processing industries, food and beverage, and any application requiring high chemical resistance and non-stick properties.
  
  2. Reinforced PTFE (RPTFE)
  
  Characteristics: RPTFE includes a filler (usually glass or carbon) to improve the material’s strength, wear resistance, and dimensional stability.
  
  Applications: Used in applications where pure PTFE’s properties are desired but with enhanced durability and reduced deformation under load.
  
  3. Nylon Coating
  
  Characteristics: Nylon provides good wear resistance and strength, along with excellent resistance to certain chemicals.
  
  Applications: Common in oil and gas applications and other areas where the seat may be exposed to hydrocarbons and where impact resistance is beneficial.
  
  4. Elastomeric Coatings (EPDM, NBR, Viton)
  
  Characteristics: Rubber materials like EPDM (ethylene propylene diene monomer), NBR (nitrile butadiene rubber), and Viton (fluoroelastomer) offer good sealing capabilities, flexibility, and, in the case of Viton, high-temperature and chemical resistance.
  
  Applications: Chosen based on their compatibility with the fluid medium. EPDM is suitable for water and mild chemicals, NBR for oils and fuels, and Viton for high-temperature and chemical applications.
  
  5. Stellite Overlay
  
  Characteristics: Stellite is a cobalt-chromium alloy known for its excellent wear and corrosion resistance, as well as its ability to perform under high temperatures.
  
  Applications: Ideal for severe service applications, such as those in the power generation and oil and gas industries, where valves are subject to high wear and harsh conditions.
  
  6. Electroless Nickel Plating
  
  Characteristics: Provides a uniform and corrosion-resistant coating that also offers good wear resistance and hardness.
  
  Applications: Used in a wide range of applications, including water and wastewater treatment and processing industries, for general corrosion protection.
  
  7. Ceramic Coating
  
  Characteristics: Ceramic coatings provide exceptional hardness, wear resistance, and thermal protection.
  
  Applications: Suitable for extreme wear and high-temperature applications, such as in the mining and minerals processing industry.
  
  8. Chrome Plating
  
  Characteristics: Chromium plating enhances surface hardness, wear resistance, and corrosion protection.
  
  Applications: Applied in industrial applications where durability and longevity of the seat are critical.
  
  Selecting the appropriate seat material and treatment depends on the valve’s application, including the nature of the fluids involved, operating pressures and temperatures, and specific industry requirements. By customizing the seat material and applying specialized treatments, butterfly valves can achieve optimal performance and reliability in a wide range of environments.
  Applications
  
  Metal-seated butterfly valves are chosen for their robustness in challenging environments, including:
  - Power Generation: For handling steam and high-temperature water in cooling systems and boilers.
  - Chemical and Petrochemical Industries: In processes involving corrosive fluids, high temperatures, and where valve durability is crucial.
  - Mining and Minerals Processing: For slurry and abrasive material handling where valve wear is a concern.
  - Pulp and Paper Manufacturing: In applications involving high-temperature liquids and corrosive chemicals used in the pulping process.
  - Considerations
    
    When selecting a metal-seated butterfly valve, several factors should be considered to ensure it meets the application’s needs:
    
    Sealing Requirements: While metal-seated valves are durable and handle extreme conditions, they might not achieve the absolute tight shut-off possible with soft-seated valves. Consider the application’s leakage tolerance.
    
    Material Compatibility: Choose a valve body and seat material that is compatible with the process media and conditions to ensure long-term reliability and performance.
    
    Operational Torque: Metal-to-metal seating can require higher torque to operate the valve, impacting actuator selection and operational energy costs.
    
    Cost: Metal-seated valves, especially those made from exotic alloys for enhanced corrosion resistance, can be more expensive than soft-seated valves. However, their durability in harsh conditions may offer a lower total cost of ownership over time.
    
    In summary, metal-seated butterfly valves are an excellent choice for industrial applications that demand high durability, temperature resistance, and the ability to handle abrasive or corrosive media. Proper selection of valve materials and understanding the specific operational requirements are key to maximizing the performance and lifespan of these valves in demanding environments.
    
    .
    Double offset and triple offset butterfly valve (metal seated)

May 23, 2024/by stvvalve

How to understand Floating Ball Valves and Trunnion Ball Valves

A ball valve features a spherical disc to open and close the flow of the fluid. Ball valves represent the industry standard for pipeline shut-off applications, as their design guarantees very tight and leak-free sealing even after years of operation. The two key types of ball valves are the floating and the trunnion designs (side or top entry). The body can be cast or forged and monolithic or split (in 2 or 3 pieces). The API 6D and ASME B16.34 are key specifications.

BALL VALVES

WHAT IS A BALL VALVE

A ball valve is a type of quarter-turn valve that controls the flow of a fluid through it with a spherical disc known as a ball. The ball has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed by turning the handle 90 degrees, the ball is rotated so that the hole is perpendicular to the flow paths of the valve body, effectively blocking the flow.

Key Features

Quarter-Turn: The valve operates with a simple 90-degree turn of a handle or lever, making it quick and easy to open or close.
Full Port Design: Many ball valves are full port, meaning the hole in the ball is the same size as the pipeline, resulting in minimal friction loss.
Durability: Ball valves are known for their durability and long service life, even in high-pressure applications.
Versatility: Suitable for a wide range of applications, from water and gas to chemicals and corrosives, depending on the materials used in construction.
Sealing Mechanism: Provides excellent sealing capabilities, with many ball valves designed to be leak-proof.

Types

Floating Ball Valve: The ball is held in place by the compression of two elastomeric seats against it. The ball moves slightly within the valve body to maintain contact with the downstream seat, ensuring a tight seal.
Trunnion Mounted Ball Valve: The ball is anchored at the top and bottom, reducing the operating torque and allowing for the control of larger sizes and higher pressure services.
Top Entry & Side Entry: Refers to how the ball valve is assembled, which impacts maintenance and repair ease.

Each type of ball valve is explained in greater detail below.

Applications

Ball valves are used in a variety of applications across many industries, including water supply, gas supply, oil and petrochemical processes, manufacturing, and more. Their ability to quickly shut off flow makes them particularly useful for emergency and shut-off applications. Material selection for the valve body, ball, and seals (often made from metal, plastic, or ceramic) can vary based on the fluid’s nature, ensuring compatibility and performance across a wide range of temperatures and pressures.

BALL VALVE PARTS

A ball valve consists of several key components, each playing a crucial role in its functionality. Understanding these parts can help in selecting the right valve for a specific application, as well as in maintenance and troubleshooting. Here’s an overview of the main parts of a ball valve:

1. Body

The outer casing of the valve that holds all other components together. It can be made from a variety of materials, including stainless steel, brass, plastic, and others, depending on the application requirements.

2. Ball

The core component that controls flow through the valve. It is a spherical disc with a hole (or bore) through its center. The material of the ball usually matches or complements the body material for compatibility with the fluid being handled.

Special Treatments For The Ball Of A Ball Valve

The ball of a ball valve can undergo various special treatments to enhance its performance, durability, and suitability for specific applications. These treatments can improve the ball’s resistance to wear, corrosion, and galling, as well as its sealing capabilities. Here are some commonly applied special treatments for the ball of a ball valve:

1. Hard Coatings

Chrome Plating: A thin layer of chromium is electroplated onto the ball surface, enhancing its wear and corrosion resistance. This treatment is suitable for applications involving abrasive materials or corrosive fluids.
Nickel Plating: Similar to chrome plating, nickel plating provides corrosion resistance and increased durability, especially in environments where the valve is exposed to harsh chemicals.
Tungsten Carbide Coating: Applied using High-Velocity Oxygen Fuel (HVOF) spraying, this coating offers exceptional hardness and resistance to extreme wear and erosion.

2. Soft Coatings

PTFE (Polytetrafluoroethylene): A soft coating that provides excellent chemical resistance and reduces friction between the ball and seats. This is particularly beneficial in applications requiring tight sealing and low operating torque.
Enamel Coating: Offers good corrosion resistance and is used in applications where chemical compatibility is a concern.

3. Electroless Nickel Coating

This process deposits a uniform nickel-phosphorus or nickel-boron alloy coating on the ball, offering excellent corrosion and wear resistance. It’s particularly useful in offshore and marine applications, as well as in the processing of corrosive fluids.

4. Nitriding

Nitriding enhances the surface hardness of the ball through a heat-treating process that diffuses nitrogen into the surface. This treatment improves wear resistance and fatigue strength, making it suitable for high-pressure and high-velocity applications.

5. Cryogenic Treatment

This treatment involves cooling the ball to cryogenic temperatures and then gradually warming it up. The process stabilizes the structure of the material, improving its toughness and wear resistance. It’s especially beneficial for valves used in cryogenic services.

6. Molybdenum Disulfide Coating

A dry lubricant coating that reduces friction and improves wear resistance. It’s useful in applications where lubrication is difficult or where the valve must operate under high loads or extreme temperatures.

7. Fusion Bonded Epoxy Coating

A thick, protective coating that offers excellent corrosion protection. It’s widely used in water and wastewater applications, as well as in pipelines transporting corrosive gases and liquids.

The choice of treatment depends on the specific operational conditions, including the type of fluid handled, pressure, temperature, and the presence of abrasive or corrosive elements. These specialized treatments can significantly extend the life of a ball valve and enhance its performance in demanding industrial applications.

3. Seats

Rings that provide a seal between the ball and the valve body. When the valve is closed, the ball presses against these seats to create a tight seal, preventing fluid from leaking past. Seats can be made from soft materials (like PTFE) for better sealing or hard materials for high-temperature applications.

Special Treatments For The Seats Of A Ball Valve

The seats of ball valves play a crucial role in ensuring tight sealing and smooth operation across a wide range of applications, from low-pressure residential systems to high-pressure industrial processes. To enhance their performance, durability, and resistance to harsh conditions, several special treatments and material enhancements can be applied to ball valve seats. Here are some of the notable treatments and materials used:

1. Soft Seating Materials

PTFE (Polytetrafluoroethylene): Offers excellent chemical resistance and a low friction coefficient, suitable for a broad temperature range. Variants like reinforced PTFE (RPTFE) have added fillers to improve strength and wear resistance.
PEEK (Polyether Ether Ketone): A high-performance thermoplastic with excellent mechanical and chemical resistance properties, suitable for high-pressure and high-temperature applications.
Nylon: Provides good wear resistance and strength, suitable for certain types of oils and hydrocarbons.

2. Metal Seating

Hard Facing: Metal seats can be coated or overlaid with harder materials such as Stellite, tungsten carbide, or chromium carbide through processes like welding or thermal spraying. These treatments improve wear resistance, thermal stability, and longevity in severe service conditions, including abrasive and corrosive environments.

3. Elastomeric And Composite Materials

Viton, Buna-N (Nitrile): Elastomers offer good sealing capabilities and resistance to a variety of chemicals and temperatures. They are used in applications where softer sealing materials are needed for improved sealing at lower pressures.
Composite Materials: Seats made from a combination of materials, such as fibrous reinforcements in a resin matrix, offer enhanced performance characteristics, including resistance to wear and chemical attack.

4. Surface Treatments

Electroless Nickel Plating (ENP): A chemical process that deposits a nickel-phosphorus coating on the surface of the seat. ENP improves corrosion resistance and hardness, enhancing the seat’s durability in corrosive environments.
Surface Coatings: Various coatings can be applied to improve resistance to chemicals, temperature, and wear. Examples include PFA (Perfluoroalkoxy) and FEP (Fluorinated Ethylene Propylene) coatings, which are types of fluoropolymers with excellent chemical resistance.

5. Seat Design Enhancements

Live-Loaded Seats: Some ball valve seats are designed with live-loading mechanisms, such as spring energizers, to maintain consistent sealing force against the ball. This compensates for wear and thermal expansion, ensuring a reliable seal over the valve’s lifespan.

Selecting the appropriate seat material and treatment depends on several factors, including the type of fluid being handled, operating pressures and temperatures, and specific application requirements. By choosing the right seat treatment, users can significantly enhance the performance, reliability, and service life of ball valves in their systems.

4. Stem

Connects the ball to the control mechanism (like a handle or actuator) outside the valve. The stem allows for the rotation of the ball, typically a quarter turn (90 degrees) from the open to the closed position. It’s designed to prevent leakage from the valve body to the atmosphere.

5. Handle Or Actuator

Used to manually or automatically control the valve’s position. A manual handle is turned to rotate the stem and the attached ball. Actuators, which can be pneumatic, electric, or hydraulic, allow for remote operation and can be used for more precise control in automated processes.

6. Packing

A sealant material around the stem to prevent leaks. Packing is often made from PTFE or graphite and is compressed by a packing nut or gland follower to ensure a tight seal.

7. O-Rings/Gaskets

Provide additional sealing at various points, such as between the valve body and the bonnet (if the valve design includes a bonnet) and around the stem. The material depends on the application’s temperature and pressure conditions.

8. Bonnet

Some ball valve designs include a bonnet, which is a section of the valve body covering the opening where the internal parts are inserted. It can be bolted, screwed, or welded to the valve body.

9. End Connections

The interface points where the valve connects to the piping system. Common types include threaded, flanged, and socket weld connections, chosen based on the piping system’s design and requirements.

Understanding these components and their materials is essential for selecting a ball valve that meets the operational requirements of temperature, pressure, flow control, and compatibility with the processed fluids. Proper selection ensures reliable performance and longevity of the valve in the system.

BALL VALVE ADVANTAGES AND DISADVANTAGES

Ball valves have the following advantages advantages:

can be quickly opened and closed with a quarter-turn movement
ensure a very tight seal without the need for high torque forces
have a compact design (this is the main difference between a ball valve and a gate valve – which are both on/off devices)

The disadvantages of ball valves are:

valve has poor regulating and throttling capabilities, as it is designed for pipeline shut-off instead of flow modulation (this is an ideal function for globe valves): throttling causes the partially exposed seat to erode because of the high-velocity flow and pressure experienced by the valve. The wear may lead to a leakage of the valve progressively.
valve can’t be used for slurries, as the accumulation of suspended particles and debris would make the valve leak. These particles may solidify in the cavities in the proximity of the ball and seats. Ball valves are way more very efficient with gases and other liquid fluids (even challenging chemicals such as dry chlorine, hydrofluoric acid or hydrochloric acid, and oxygen).
may be difficult to clean (except for top entry design)

The open, close,d or partially open position of the valve can be detected by looking at the position of the lever:

when the lever is aligned to the pipe, the valve is open; when it is perpendicular to the pipe, the valve is closed;
when it is in any other position, the valve is partly open (or partly closed) and is modulating the flow.

These valves belong to the family of “quarter turn” valves or “1/4 turn valves” (together with butterfly and plug valves), as the opening and closing operations are executed by turning a lever connected to the disc by 90 degrees.

The key ball valve specifications are the API 6D, BS 5351 (forged) and ASME B16.34 (pressure and temperature ratings), ASME B16.5/B16.47 (flanged ends) and ASME B16.25 (butt welding ends).

HOW DOES A BALL VALVE WORK?

A ball valve operates using a simple but effective mechanism that involves a quarter-turn rotational motion to open or close the flow of fluid. The core component of a ball valve is a spherical disc, known as the ball, which has a hole or port through its center. Here’s a breakdown of how a ball valve works:

In The Open Position

The handle or lever of the ball valve is aligned with the pipe, indicating that the valve is open.
The hole in the ball is positioned in line with the flow direction of the pipe, allowing fluid to pass through the valve with minimal resistance.
As the ball rotates to this position, the fluid can flow freely through the hole, enabling full flow through the valve.

In The Closed Position

To close the valve, the handle or lever is turned 90 degrees from the open position. This quarter-turn movement rotates the ball so that the hole is perpendicular to the flow direction of the pipe.
When the hole or port in the ball is perpendicular to the flow path, it blocks the flow of fluid, effectively stopping the flow through the valve.
The sealing mechanism around the ball (typically elastomeric seats) ensures a tight seal when the valve is closed, preventing leaks.

Key Functional Aspects

Quarter-Turn Operation: The ball valve’s design allows for quick and easy operation, making it an efficient choice for controlling fluid flow. The 90-degree turn offers a clear visual indication of the valve’s position.
Sealing: The effectiveness of a ball valve’s seal, when in the closed position, is aided by the pressure of the fluid which pushes the ball against the downstream seat. This pressure enhances the sealing effectiveness, making ball valves suitable for high-pressure applications.
Versatility: Ball valves can handle various fluids, including gases, liquids, and slurries. Their design minimizes pressure drop and allows for bidirectional flow control in the fully open position.
Durability: The simplicity of the ball valve’s design contributes to its durability and reliability, with many ball valves capable of maintaining their sealing ability over thousands of cycles.

Ball valves are favored for applications requiring reliable and rapid shut-off, offering a practical solution for flow control across a broad range of industrial and residential settings.

BALL VALVE TYPES

Ball valves can be classified according to multiple criteria:

Ball valve design: floating, trunnion mounted, and double bleed and block
Number of valve’s ports: the standard type is with 2 ports design (1 inlet, 1 outlet), but 3-way design is also available (1 inlet and 2 outlets or vice-versa)
Bore size: full bore or reduced bore (FB vs. RB), and V-notch
Body assembly: unibody (the ball body is made out of one single piece of cast or forged steel), 2 pieces or 3 pieces (the body results from the assembly of two or three different parts)
Ball access: side entry or top entry (depending on the fact that the ball can be accessed, for maintenance, from the side of the valve or from its top)
Seat Type: metal or soft (Teflon)

Let’s now delve into the characteristics of each different type of ball valve.

FLOATING BALL VALVE

A floating ball valve is a type of ball valve where the ball is not rigidly fixed but is allowed to float between the valve seats. In this design, the ball is held in place by the compression of two elastomeric seats, one on each side of the ball.

The ball has some freedom to move (float) within the valve body. The term “floating” refers to the ball’s ability to move slightly along the axis of the valve.

How It Works

When the valve handle (or actuator) is turned to open the valve, the ball rotates to a position where the hole through the ball is aligned with the valve’s inlet and outlet, allowing fluid to flow through. When the valve is closed, the handle rotates the ball so that it blocks the flow path.

Upon closing the valve, the pressure of the fluid acts on the ball, pushing it against the downstream seat. This action enhances the seal and prevents fluid from leaking past the ball. The floating design means that the sealing pressure against the ball increases with increased fluid pressure, thereby improving the sealing efficiency as the system pressure rises.

Advantages Of Floating Ball Valves

Tight Sealing: The pressure-assisted sealing mechanism ensures a reliable seal between the ball and the seats, making floating ball valves suitable for a wide range of applications.
Simplicity and Durability: With fewer moving parts and a simple design, floating ball valves are durable and require minimal maintenance.
Versatility: They can be used in various applications, handling a wide range of fluids and operating conditions.

Applications

Floating ball valves are commonly used in industries such as water and wastewater treatment, chemical and petrochemical processing, oil and gas, and manufacturing. They are suitable for applications requiring reliable shut-off capabilities, such as in pipelines, storage facilities, and distribution systems. Floating ball valves are typically used in low to medium-pressure and temperature applications.

Considerations

While floating ball valves are suitable for a wide range of applications, the floating design may not be as effective in very high-pressure systems where the ball could be pushed too hard against the seat, potentially leading to seat deformation and increased operational torque. For such high-pressure applications, trunnion-mounted ball valves, where the ball is supported by bearings and the pressure load is not entirely on the seats, might be more appropriate.

Floating and trunnion ball valves design

When the shaft of the floating ball valve is moved, a load is applied to the ball which gets pressed against its seats.

This design, which is lightweight and economical, suits bore sizes up to 10 inches: above this bore size, the seats of the valve would not be able to withstand heavier and heavier balls and the valve would not operate safely and efficiently.

Floating valves allow a bi-directional shut-off of the flow (as the trunnion type).

Floating ball valve

TRUNNION BALL VALVE

A trunnion ball valve is a type of ball valve that utilizes a fixed ball design to control the flow of fluid. Unlike floating ball valves, where the ball is allowed to float between the valve seats, in trunnion ball valves, the ball is anchored at the top and bottom by trunnions. These trunnions, essentially extensions of the ball or additional support mechanisms, hold the ball in a fixed position while allowing it to rotate.

How It Works

The ball in a trunnion ball valve has a hole through its center. When the valve is open, this hole is aligned with the flow path, allowing fluid to pass through. Turning the valve’s handle or actuator rotates the ball to block the flow path, stopping the flow. The trunnions absorb the line pressure, reducing the load on the valve seats and ensuring a tight seal regardless of pressure fluctuations.

Key Features And Advantages

Low Operational Torque: Because the ball is supported by trunnions, there’s less friction between the ball and the seats during operation, which translates to lower torque requirements. This makes it easier to operate, especially for larger valve sizes or in high-pressure applications.
High Pressure and Temperature Capabilities: Trunnion ball valves are well-suited for high-pressure and high-temperature applications. The trunnion design effectively manages the thrust from line pressure, preventing excess stress on the valve components.
Durability and Reliability: The fixed ball design minimizes wear on the seats and ensures consistent performance over time, contributing to the valve’s longevity and reliability.
Double Block and Bleed (DBB) Capability: Many trunnion ball valves offer DBB functionality, allowing for maintenance and pressure verification without shutting down the entire system.

Applications

Trunnion ball valves are used in a wide range of industrial applications, especially where high pressure and large diameters are involved, such as:

Oil and Gas: For controlling flow in pipelines, processing facilities, and offshore platforms.
Petrochemical and Chemical Manufacturing: In systems requiring robust valves that can handle high pressures and corrosive fluids.
Power Generation: For steam, water, and feedwater systems within power plants.
Water and Wastewater Treatment: In high-pressure lines and for applications requiring durable and reliable shut-off.

Considerations

While trunnion ball valves offer several advantages, they are typically more expensive than floating ball valves due to their more complex design and manufacturing process. They are also generally larger and heavier, which may be a consideration for installation and support structures. Despite these factors, their reliability and performance in demanding conditions make them a preferred choice for many high-pressure and large-scale applications.

TOP ENTRY BALL VALVE

A top entry ball valve is a type of ball valve where the main components, including the ball and seats, can be accessed and serviced from the top of the valve without removing the entire valve body from the pipeline. This design provides a significant advantage in terms of maintenance and repair.

Design And Operation

Ball Mechanism: Similar to other ball valves, a top entry ball valve uses a spherical ball with a hole through its center to control fluid flow. The valve opens when the ball’s hole is aligned with the flow path and closes when rotated 90 degrees.
Access: The distinguishing feature of a top entry ball valve is the single-piece body design that allows access to the valve internals through a removable bonnet or cover on the top. This design means that the valve internals can be inspected, repaired, or replaced without detaching the valve body from the pipeline.
Sealing and Support: Top entry ball valves can be designed with floating or trunnion-supported balls, depending on the application requirements. They also feature robust sealing mechanisms to prevent leaks, which can be easily replaced or serviced due to the top entry design.

Advantages

Ease of Maintenance: The primary advantage is the ease of maintenance and repair. Valve components can be serviced directly on the line, reducing downtime and operational costs.
Versatility: Top entry ball valves are suitable for a wide range of applications, pressures, and temperatures. They can be used in critical and high-performance settings, including the oil and gas industry, power generation, and process industries.
Durability and Reliability: These valves are built for durability and reliability, with designs that can handle high pressure and adverse conditions effectively.

Applications

Top entry ball valves are used in various industrial applications where valve accessibility and ease of maintenance are crucial, especially in high-pressure and high-temperature environments. Common applications include:

Oil and Gas: For onshore and offshore pipelines, production facilities, and refining processes where rapid maintenance may be required.
Chemical Processing: In systems handling corrosive or hazardous materials that may require frequent maintenance.
Power Generation: In feedwater, steam, and other critical power plant systems.

Differences Top-Entry And Side-Entry Ball Valves

Top entry and side entry ball valves are two distinct designs within the ball valve family, each offering specific advantages for different applications. The primary difference lies in how the ball and internal components are accessed and maintained. Here’s a breakdown of each type:

Top Entry Ball Valve

Design: In a top entry ball valve, the ball and seats can be accessed from the top of the valve. The valve body is a single piece, with a removable bonnet or cover on top that provides direct access to the valve internals without removing the valve from the pipeline.

Advantages:

Maintenance: Allows for easier maintenance, inspection, and replacement of the internals (ball, seats, seals) without detaching the valve from the pipeline, saving time and reducing downtime.
Application: Suitable for high-pressure and high-temperature applications, as well as in situations where inline maintenance is necessary or where system downtime needs to be minimized.

Considerations:

Typically more expensive due to the precision engineering required for the top entry design.
Often used in critical or hard-to-reach areas where valve removal would be challenging.

Side Entry Ball Valve (Split Body Ball Valve)

Design: The side entry ball valve, often referred to as a split body ball valve, features a body that is divided into two or three pieces, bolted together. The ball is inserted from the side when assembling the valve. The body joint is typically along the horizontal axis for a two-piece design and may include a third piece (center piece) for three-piece designs.

Advantages

Cost-Effectiveness: Generally more cost-effective than top entry valves, making them suitable for a wide range of applications.
Versatility: Available in a wide variety of sizes and pressure ratings, suitable for many industrial applications.

Considerations

Maintenance or repair requires the valve to be removed from the pipeline, which can increase system downtime.
The seal at the body joint may have specific pressure limitations, influencing the valve’s suitability for high-pressure applications.

Key Differences (Top Vs. Side Entry)

Maintenance Accessibility: Top entry valves allow for inline maintenance without removing the valve from the pipeline, while side entry valves need to be fully removed for servicing.
Construction and Cost: Top entry valves have a one-piece body design that can be more expensive to manufacture, whereas side entry valves have a split body design that is generally more cost-effective.
Application Suitability: The choice between top entry and side entry may depend on the application’s maintenance requirements, cost considerations, and pressure/temperature demands.

In summary, the decision between a top entry and side entry ball valve often comes down to the specific needs of the application, including maintenance practices, budget constraints, and operational conditions. Each type offers unique benefits that make it suitable for different industrial environments.

Trunnion-mounted ball valves, as well as floating ball valves, are available with a “side entry” and “top entry” design.

The top entry design is specified when frequent inline maintenance activities are expected on the valve.

This is because top-entry ball valves allow easier and faster access to the ball and the valve trim compared to side-entry valves (which require more maintenance time and space for the same operations).

Final Considerations About Top-Etntry Ball Valves

While top-entry ball valves offer significant maintenance advantages, they may come with a higher initial cost compared to other ball valve types due to their design complexity and manufacturing requirements. Additionally, their selection should consider the specific application’s pressure, temperature, and fluid compatibility to ensure optimal performance and longevity.

3-WAYS BALL VALVE (OR “MULTIPORT”)

A 3-way ball valve is a type of ball valve designed to control the flow of fluids in three different directions. It is characterized by having three ports (inlet and two outlets, or one inlet and two outlets), making it versatile for various applications where flow diversion, mixing, or directional control is needed. The internal ball typically has either an L-shaped or T-shaped port, allowing for different flow patterns depending on its position.

How It Works

L-Port Configuration: The L-shaped port connects the center port to one of the side ports at a time, making it suitable for diverting flow from one line to another. By rotating the ball, the valve can alternate between connecting the inlet to either of the two outlets.
T-Port Configuration: The T-shaped port can connect all three ports simultaneously or block one port while connecting the other two. This configuration is useful for mixing two inlet flows or dividing one inlet flow into two outlets.

Key Features

Versatility: 3-way ball valves can serve multiple functions, such as stopping and starting flow, changing the flow direction, mixing, or splitting the flow within a single valve body.
Easy Operation: Like other ball valves, 3-way ball valves offer quick and efficient operation, typically with a quarter-turn mechanism to change flow paths.
Compact Design: These valves can replace multiple two-way valves and fittings in a system, saving space and reducing potential leak points.

Applications

3-way ball valves are widely used across various industries for different purposes, including:

Chemical Processing: For directing chemical flows between different processing stages or mixing chemicals.
HVAC Systems: To control the direction of heating or cooling media.
Food and Beverage: In systems requiring the diversion of fluids or mixing of ingredients.
Water Treatment: For directing water flow through different treatment paths.

Selection Considerations

When selecting a 3-way ball valve, consider:

Flow Requirements: Determine the required flow pattern (L-port or T-port) based on the application’s needs.
Material Compatibility: Ensure the valve materials are compatible with the fluids being handled, considering factors like corrosion resistance and food safety.
Pressure and Temperature: Select a valve that can withstand the operating pressure and temperature conditions of the system.
Actuation: Decide between manual operation or automated actuation (electric, pneumatic, hydraulic) based on system requirements.

In summary, 3-way ball valves offer a flexible and efficient solution for controlling flow directions in a piping system, accommodating a variety of operational needs with simple adjustments.

FULL PORT VS REDUCED PORT BALL VALVES

These concepts refer to the relation between the bore diameter of the valve and the connected piping system. The term “port” can be also referred to as “bore” (full bore/small bore).

Full port and reduced port ball valves are two common design variations found in ball valves, each serving specific operational purposes based on flow requirements and pressure drop considerations. Understanding the differences between them is crucial for selecting the appropriate valve type for a particular application.

Full Port Ball Valve (Full Bore)

Design: In a full port ball valve, the diameter of the ball’s hole (bore) matches the inner diameter of the connecting pipeline. This design ensures that there is no restriction in the flow path when the valve is fully open.
Advantages: Minimal pressure drop across the valve, which is especially beneficial in applications requiring the preservation of flow rate and pressure. It also allows for pigging operations in pipelines, where a cleaning pig is sent through the pipe to remove debris and buildup.
Applications: Full port valves are ideal for applications where flow efficiency is critical and for systems that require regular pigging for maintenance.

Reduced Port Ball Valve (Reduced Bore)

Design: The bore diameter of a reduced port ball valve is smaller than the pipeline’s diameter. This results in a flow path that is somewhat restricted compared to the full port design.
Advantages: Reduced port valves are generally smaller and less expensive than full port valves of the same nominal size. The smaller bore also requires less torque to operate, which can reduce the size and cost of the actuation mechanism.
Applications: Suitable for applications where flow rate and pressure drop are less critical. They are commonly used in applications where space and cost savings are desired without significantly compromising the system’s performance.

Key Differences

Flow Path and Pressure Drop: Full port valves offer an unrestricted flow path, resulting in lower pressure drops, while reduced port valves introduce some restriction and higher pressure drops.
Size and Cost: Reduced port valves are typically more compact and cost-effective than full port valves, making them attractive for applications where space is limited, and the full flow capacity is not required.
Operational Efficiency: The choice between full and reduced port often depends on the system’s requirements for flow efficiency and pressure maintenance. Full port valves are preferred in systems that cannot tolerate significant pressure drops or where pipeline pigging is necessary.

In summary, the choice between full port and reduced port ball valves depends on the specific requirements of the application, including considerations of flow rate, pressure drop, operational efficiency, and cost. Understanding these differences ensures the selection of the most appropriate valve type to meet the system’s needs effectively.

V-PORT BALL VALVE

A V-Port ball valve, also known as a V-Ball or V-Notch ball valve, is a specialized type of ball valve designed for more precise flow control and regulation compared to standard ball valves. This valve features a ball with a V-shaped cutout on its surface, giving it the name “V-Port.” The unique shape of the V-Port allows for better throttling control and rangeability, making it particularly suited for applications requiring precise flow modulation.

Design And Operation

V-Port Design: The angle of the V-notch cut into the ball can vary, typically ranging from 15 to 90 degrees. The shape and angle of the V-Port directly affect the flow characteristics, allowing for linear or equal percentage flow control. As the valve is opened or closed, the V-shaped portion provides a gradual change in flow area, enabling fine adjustment of flow rate.
Operation: Like other ball valves, V-Port ball valves operate with a quarter-turn mechanism. Rotating the valve handle 90 degrees opens or closes the valve, but the precise shape of the V-Port allows for more nuanced control over the flow as the valve moves between open and closed positions.

Advantages

Enhanced Flow Control: The V-Port design offers superior control over fluid flow, especially in partially open positions, making it ideal for throttling applications.
High Rangeability: V-Port ball valves can effectively manage a wide range of flow rates, providing flexibility across various operational conditions.
Reduced Cavitation and Flashing: The gradual change in flow area helps minimize the risks of cavitation and flashing, common challenges in fluid control applications.
Durability: V-Port ball valves maintain the inherent durability and reliability of traditional ball valves, suitable for high-pressure and high-temperature applications.

Applications

V-Port ball valves are used in diverse industries where precise flow regulation is required, including:

Chemical Processing: For controlling the flow of aggressive or corrosive fluids.
Water and Wastewater Treatment: In applications requiring fine adjustment of water flow.
Food and Beverage Production: Where precise flow control is necessary for process accuracy.
Pulp and Paper Manufacturing: For controlling the flow of slurry and other process fluids.

Selection Considerations

When selecting a V-Port ball valve, consider factors such as the specific flow control requirements, the fluid properties (including viscosity and potential for particulate matter), operating pressures and temperatures, and the valve materials’ compatibility with the process fluid.

In summary, V-Port ball valves offer enhanced flow control capabilities, making them a valuable option for applications requiring precise flow regulation. Their design combines the robustness and reliability of standard ball valves with improved performance for throttling and modulation tasks.

SEGMENTED BALL VALVE

A segmented ball valve, also known as a V-notch ball valve, is a specialized type of ball valve designed to provide precise flow control, especially in applications involving liquids with varying viscosities or slurries. It combines the robust sealing characteristics of a traditional ball valve with enhanced control capabilities, thanks to its unique ball design.

Design

The key feature of a segmented ball valve is its ball segment or V-notch design. The ball has a V-shaped cutout on one side, which gradually opens or closes as the valve is turned, allowing for more precise modulation of flow than a standard ball valve. The “segment” refers to the part of the ball that is cut out, and it can rotate within the valve body to regulate the flow.

How It Works

As the valve handle or actuator is turned, the V-notch segment of the ball rotates, aligning more or less with the flow path. This design allows for a range of flow control, from fully open to nearly closed, with the V-notch providing a shearing action that is effective at controlling the flow of slurry or viscous fluids.

Key Features

Precise Flow Control: The V-notch design enables finer control over the flow rate, making it suitable for throttling applications.
Shearing Action: The V-notch can cut through solids and slurries in the fluid, reducing clogging and ensuring smoother operation in challenging conditions.
High Rangeability: The valve offers a wide range of flow capacities, from fully open to minimal flow, allowing for versatile use across different applications.
Durability: Segmented ball valves are designed to withstand harsh operating conditions, including high pressures and temperatures.

Applications

Segmented ball valves are used in various industrial applications where precise flow control and durability are required, including:

Chemical Processing: For handling corrosive fluids, viscous products, or slurry mixtures where precise flow modulation is necessary.
Pulp and Paper Manufacturing: In processes involving fibrous slurries, where the valve’s shearing action can prevent clogging.
Water and Wastewater Treatment: For controlling the flow of water with varying levels of particulate matter.
Food and Beverage: In applications involving viscous liquids or products with solids.

Considerations

When selecting a segmented ball valve, it’s important to consider the specific requirements of your application, including the fluid’s nature, pressure and temperature conditions, and the degree of flow control needed. The material of the valve and its components should be compatible with the process fluid to ensure longevity and reliability.

In summary, segmented ball valves offer an efficient solution for applications requiring precise flow control and the ability to handle difficult fluids, combining the benefits of ball valve sealing with the adjustability of a control valve.

BALL CONTROL VALVE

A ball control valve is a type of control valve that uses a ball with a hole through it to regulate the flow of a fluid. It combines the spherical closure element of a traditional ball valve with the ability to modulate flow, making it suitable for precision control applications. Ball control valves are designed to offer variable control of fluid flow, allowing for adjustment from full flow to minimal flow based on the position of the ball.

Design Features

Rotary Ball: The core component is a rotary ball with a bore through the center. The position of the ball (and thus the alignment of the bore with the flow path) is adjusted to control the flow rate.
V-Port: Many ball control valves feature a V-shaped cut or notch on the ball or in the bore, enhancing their ability to provide finer control over a wide range of flow rates. The “V” shape allows for more precise control as the valve moves from the closed to the open position.
Actuation: Ball control valves are often operated by pneumatic, electric, or hydraulic actuators, allowing for remote control and automation of the valve’s position in response to system demands.
Operational Advantages
- Precise Flow Control: Offers excellent control over flow rates, making it ideal for applications where the flow needs to be adjusted or regulated accurately.
- High Rangeability: The design allows for a wide range of flow capacities, enabling precise control from fully open to nearly closed positions.
- Good Shut-Off Capabilities: When fully closed, ball control valves provide a tight seal, similar to standard ball valves, making them suitable for on/off control in addition to flow modulation.
- Durability: The robust design of ball control valves, especially those with hard-sealed components, can handle high-pressure applications and aggressive media.
Applications

Ball control valves are used in a variety of industries and applications, including:
- Process Industries: For controlling the flow of gases, liquids, and even slurries in chemical, petrochemical, and pharmaceutical processes.
- Water Treatment: In systems requiring precise control of water flow, such as in filtration, distribution, and wastewater treatment.
- Oil and Gas: For regulating the flow in pipelines, production processes, and refining operations.
- Food and Beverage: In applications involving the control of liquids and semi-liquids during processing and manufacturing.
Selection Considerations

When selecting a ball control valve, consider factors such as:
- Fluid Compatibility: Ensure the materials of the valve are compatible with the process fluid to prevent corrosion and wear.
- Pressure and Temperature Ratings: The valve must be capable of operating within the system’s pressure and temperature ranges.
- Flow Characteristics: Consider the required flow pattern (e.g., linear or equal percentage) and rangeability to ensure the valve meets the application’s control needs.
In summary, ball control valves are an effective solution for applications requiring both precise flow modulation and reliable shut-off capabilities. Their versatility and durability make them a popular choice in various industrial processes where control accuracy is paramount.

BALL VALVE VS. OTHER TYPES OF VALVES

Ball Valve Vs Gate Valve

Ball valves and gate valves are two commonly used types of valves in piping systems, each serving specific purposes with distinct advantages and operational differences. Here’s a comparison to highlight the key aspects of ball valves versus gate valves:

Ball Valve
- Operation: Utilizes a rotating ball with a hole through its center to control flow. Turning the valve’s handle 90 degrees opens or closes the flow path.
- Sealing: Offers a tight seal with low torque, making it suitable for applications requiring a leak-proof operation.
- Flow Control: Provides excellent on/off control but is not typically used for flow modulation, as partial opening can create turbulent flow and potentially damage the valve.
- Pressure Drop: Generally experiences a lower pressure drop when fully open compared to gate valves, due to the straight flow path.
- Applications: Widely used for gas and liquid applications where quick and full shutoff is required, including residential, industrial, and commercial plumbing and water systems.
Gate Valve
- Operation: Operates by lifting a gate out of the path of the fluid. Turning the handle or wheel opens or closes the valve by moving the gate vertically.
- Sealing: When fully open or fully closed, gate valves provide a good seal. However, they are prone to wear and leakage over time, especially in the partially open position.
- Flow Control: Primarily designed for on/off control and not recommended for throttling as the partially open gate can be damaged by the fluid flow.
- Pressure Drop: When fully open, gate valves offer very little resistance to flow, resulting in a minimal pressure drop.
- Applications: Ideal for applications where a straight flow path and minimal restriction are desired, such as in water and wastewater treatment, oil and gas industries, and other situations requiring minimal valve operation.
Key Differences
- Functionality: Ball valves are better for applications requiring fast, frequent operation and tight shutoff. Gate valves are preferred for applications where the valve remains either fully open or fully closed for extended periods.
- Flow Regulation: Ball valves are not suited for precise flow control, while gate valves, although not designed for throttling, can provide finer control when opening and closing.
- Maintenance: Ball valves generally require less maintenance than gate valves, as their design is simpler and more resistant to wear from the turbulent flow.
- Cost: The cost can vary depending on the size, material, and specific application requirements. However, ball valves tend to be more cost-effective for smaller sizes, while gate valves can be more economical for larger diameters.
In summary, the choice between a ball valve and a gate valve depends on the specific requirements of the application, including the need for flow control, frequency of operation, and budget considerations. Each valve type offers distinct advantages that make it suitable for different operational contexts.
Ball Valve Vs Globe Valve

Ball valves and globe valves are both critical components used in piping systems for controlling flow, but they have distinct design features, operational mechanics, and applications that make them suited to different tasks.

Here’s a breakdown of the key differences between ball valves and globe valves:

Ball Valve
- Design: Features a spherical disc (the ball) with a hole through its center. The ball rotates within the valve body to open or close the flow path.
- Operation: Operates with a quarter-turn (90-degree) movement, offering quick and easy shutoff. The handle’s position (parallel or perpendicular to the pipe) indicates the valve’s status (open or closed).
- Flow Control: Primarily used for on/off control due to its design. While it can be used for throttling, it’s not as precise as a globe valve for this purpose.
- Sealing: Provides a tight seal with minimal wear over time, making it suitable for applications requiring leak-proof operation.
- Pressure Drop: Generally has a lower pressure drop when fully open, as the flow path is straight through the ball.
- Applications: Widely used in applications requiring fast and frequent operation, including gas, liquid, and even slurry services, due to its robust design and effective sealing.
Globe Valve
- Design: Characterized by a body with a Z-shaped partition and a moveable disc or plug that seats against an opening in the partition to regulate flow.
- Operation: Utilizes a multi-turn stem operation, requiring several turns to open or close, which allows for precise control of the flow rate.
- Flow Control: Excellently suited for throttling and regulating flow due to its design, which allows for fine adjustments of the disc position.
- Sealing: Effective sealing capabilities, but the design can lead to more wear on the seating surface due to the disc’s sliding motion against the seat.
- Pressure Drop: Typically experiences a higher pressure drop compared to ball valves because of the tortuous flow path.
- Applications: Commonly used in applications requiring precise flow control, such as in heating and cooling systems, and in processes where flow needs to be adjusted regularly.
Key Differences
- Functionality and Control: Ball valves are best for quick, on/off control but can offer some throttling capabilities. Globe valves excel in applications requiring precise flow regulation.
- Pressure Drop: Ball valves have a lower pressure drop in the open position due to the straight-through flow path, making them more efficient for certain applications. Globe valves, with their Z-shaped flow path, incur a higher pressure drop but provide better flow control.
- Operational Speed: Ball valves can be operated quickly with a quarter-turn, making them suitable for emergency and safety-related applications. Globe valves require multiple turns, offering slower but more precise control.
Choosing between a ball valve and a globe valve depends on the specific needs of the application, including the type of control required (on/off vs. throttling), operational efficiency (pressure drop concerns), and the fluid service conditions (temperature, pressure, and corrosiveness).

Ball Valve Vs. Butterfly Valve

Ball valves and butterfly valves are both popular choices for controlling the flow of fluids in piping systems, but they have distinct features, operating mechanisms, and suitability for different applications. Understanding their differences is key to selecting the most appropriate valve for a specific use case.

Ball Valve
- Design: Features a spherical disc (the ball) with a hole through its center. The ball rotates within the valve body to open or close the flow path.
- Operation: Utilizes a quarter-turn mechanism for operation, allowing for quick and easy shutoff. The handle’s position directly indicates the valve’s open or closed status.
- Sealing: Typically offers excellent sealing capabilities due to the tight fit between the ball and the valve seats, making it suitable for gas and high-pressure applications.
- Flow Control: While primarily used for on/off control, some ball valves are designed for flow regulation. However, they are not as precise in controlling flow as butterfly valves.
- Pressure Drop: When fully open, ball valves usually present a minimal pressure drop because the hole in the ball allows for nearly unrestricted flow.
Butterfly Valve
- Design: Consists of a flat disc that rotates around a central axis within the valve body. The disc’s position relative to the flow direction controls the fluid passage.
- Operation: Also operates with a quarter-turn mechanism, allowing for rapid opening and closing. The lever or gear operator indicates the valve’s position.
- Sealing: Offers good sealing with the use of elastomeric seat materials but may not be as tight as a ball valve, especially under high-pressure conditions.
- Flow Control: Excellently suited for throttling applications due to the ease with which the disc can be positioned to regulate flow. Provides more precise flow control compared to ball valves.
- Pressure Drop: Even when fully open, the presence of the disc within the flow path means butterfly valves typically have a higher pressure drop than ball valves.
Key Differences
- Application Suitability: Ball valves are preferred for applications requiring tight shutoffs, such as in gas transmission and high-pressure scenarios. Butterfly valves are favored in applications where precise flow control and regulation are necessary, especially in larger diameter pipes where ball valves would be impractical or too expensive.
- Operational Efficiency: Ball valves provide a more secure seal and are generally more effective for on/off control, while butterfly valves offer superior capabilities for flow modulation and adjustment.
- Cost and Space Considerations: Butterfly valves tend to be more cost-effective for larger sizes and require less space for installation due to their compact design compared to ball valves.
The choice between a ball valve and a butterfly valve ultimately depends on specific factors like the fluid’s nature, pressure, and temperature conditions, required flow control precision, space availability, and budget constraints. Each valve type has its advantages and ideal use cases, ensuring optimal performance for various applications.
MATERIALS FOR BALL VALVES

Cast Vs. Forged Ball Valves Body Materials

Ball valves are manufactured either with cast or forged body materials (which can be monoblock, or split, body types).

When Forged Bodies?

Generally, ball valves below 2 inches in diameter are manufactured in 2 pieces or 3 pieces body configurations (the most common materials used for forged ball valves are ASTM A105 for high-temperature service, ASTM A350 LF2/LF3 for low-temperature service, and ASTM A182 F304/F316 for stainless steel valve or higher grades, such as duplex valves ASTM A182 F51 and super duplex ASTM A182 F53/F55).

Forged bodies are also used for high-pressure valves of higher bore sizes (with 2 or 3-piece split body construction).

Examples of forged ball valves (small size and stainless steel valve with a forged body, trunnion mounted).

When Cast Bodies?

Valves in sizes above 2 inches are generally manufactured with cast body materials (the most common grades are ASTM A216 WCB for high temp. service, ASTM A352 for low-temperature service and ASTM A351 CF8, CF8M for cast stainless steel valves).

ASTM Materials For Ball Valves
- Carbon Steel: ASTM A216 WCB is a common grade used for the valve body in moderate temperature applications. It offers good strength and toughness.
- Stainless Steel: ASTM A351 CF8M (equivalent to SS316) and ASTM A351 CF8 (equivalent to SS304) are widely used for corrosion resistance in harsh environments.
- Alloy Steel: ASTM A494 CW-6MC (Inconel 625), ASTM A494 CW-12MW (Hastelloy C), and other alloys are used for high-temperature and high-corrosion applications.
- Bronze and Brass: ASTM B62 (Bronze) and ASTM B16 (Brass) are used for general low-pressure applications and are particularly common in plumbing and water systems.
API Materials For Ball Valves
- API 608: Specifies the requirements for ball valves used in the petroleum and natural gas industries. This standard covers material requirements for different classes of service, including carbon steel, stainless steel, and alloy materials.
- API 6D: While primarily a specification for pipeline valves (including gate, plug, and ball valves), API 6D also outlines material specifications for ball valves used in pipeline applications. Materials are chosen based on the pressure and temperature class of the valve.
Material Selection Considerations
- Corrosion Resistance: Stainless steel and alloy materials are selected for services involving corrosive fluids, while carbon steel may be sufficient for water, steam, and oil where corrosion is not a significant concern.
- Temperature and Pressure: High-temperature and high-pressure applications may require alloy steels or special alloys to maintain integrity under extreme conditions.
- Compatibility: The material must be compatible with the fluid to prevent contamination or degradation of the valve components.

May 23, 2024/by stvvalve

industry valve news, News

Understand Check Valves (BS 1868, API 6D, API 602)

A check valve prevents potentially damaging backflows to protect equipment like pumps and compressors. Non-return valves allow the flow of the fluid in one direction only and block reverse flows. This type of valves is available with cast and forged bodies (BS 1868, API 6D, API 602) and in several designs as swing, ball, lift, stop and piston designs.

CHECK VALVE

WHAT IS A CHECK VALVE?

Briefly, a check valve is a protection device that prevents the fluid from flowing in an unwanted direction within the piping system or the pipeline (as backflows may damage upstream equipment).

A check valve, also known as a non-return valve or one-way valve, is a type of valve that allows fluid (liquid or gas) to flow through it in only one direction. Check valves are used to prevent the backflow of fluid, automatically preventing reversed flow when the fluid in the line reverses direction. They are crucial components in various piping systems to ensure the safety and efficiency of operations.

Design And Operation

Check valves operate automatically and most do not have any valve handle or stem. The design of a check valve incorporates a mechanism that opens with forward flow and closes against reverse flow. This mechanism can vary depending on the type of check valve, but common types include ball check valves, swing check valves, and lift check valves:

Ball Check Valve: Utilizes a ball that rests on a seat within the valve body. Forward flow lifts the ball off the seat, allowing flow, while reverse flow presses the ball back onto the seat, blocking the flow.
Swing Check Valve: Features a disc or a door that swings on a hinge or a shaft. The disc swings off the seat to permit forward flow and swings back to the seat to block reverse flow.
Lift Check Valve: Contains a disc or cone that lifts vertically off the seat by the pressure of the forward flow. When the flow stops or reverses, gravity or reverse flow pushes the disc back onto the seat to stop backflow.

Applications

Check valves are used in a wide range of applications to protect equipment, maintain process conditions, and ensure directional flow, including:

Pump Protection: To prevent backflow that could damage pumps and drive systems.
Preventing Contamination: To stop backflow in systems where contamination could be a significant issue, such as in potable water supply.
Pressure Maintenance: In systems where pressure needs to be maintained in one part of the system, preventing fluid from flowing back and reducing pressure.
Safety Applications: In systems where reverse flow could lead to hazardous conditions or equipment failure, such as in gas supply systems.

Advantages And Limitations

Advantages:

Automatic operation, requiring no external controls or power.
Simple design, leading to reliability and ease of maintenance.
Available in a wide range of sizes and materials, suitable for various applications and fluids.

Limitations:

Potential for water hammer or surge pressures due to the rapid closing of the valve, especially in fast-flowing systems.
Limited flow control capabilities since they are designed primarily for preventing backflow rather than regulating flow.
Possibility of leakage if debris prevents the valve from fully closing.

In summary, check valves play a vital role in ensuring the unidirectional flow of fluids in piping systems, offering protection against reverse flow and its associated problems. Selecting the appropriate type of check valve depends on specific system requirements, including flow rate, pressure, and the nature of the fluid.

Cast steel valves are available with flanged and butt weld ends.
Forged, small-size, valves are available with threaded and socket weld connections.

These valves are represented by the following symbol in piping P&ID diagrams: Symbol for check valve in P&ID diagram

HOW TO SELECT A CHECK VALVE?

Selecting the right check valve for a particular application requires careful consideration of various factors to ensure optimal performance, reliability, and safety of the piping system. Here’s a step-by-step guide on how to select a check valve:

1. Understand The Application

Fluid Type: Determine the type of fluid (water, oil, gas, etc.), as this will influence the material selection for the check valve to ensure compatibility and prevent corrosion.
Flow Conditions: Consider the flow rate, pressure, and temperature of the system. The check valve must be capable of operating effectively under these conditions.

2. Determine The Correct Size

Pipe Size: The check valve should match the size of the connecting pipe to ensure proper fit and minimize installation issues.
Flow Requirements: Calculate the required flow rate (Cv) to ensure the valve can handle the system’s flow without causing excessive pressure drop or flow restriction.

3. Select The Valve Type

Based on the application requirements, decide on the type of check valve needed. Common types include:

Swing Check Valves: Suitable for larger pipe diameters and low-pressure drop applications.
Ball Check Valves: Ideal for viscous fluids or applications with varying flow rates.
Lift Check Valves: Best for high-pressure systems where tight sealing is required.
Wafer Check Valves: Used in space-constrained applications, offering a compact design.
Dual Plate Check Valves: Provide quick closing to prevent fluid hammer in liquid systems.

Each type of check valve is discussed later in greater detail.

4. Choose The Material

Body and Trim Material: Select materials that are compatible with the fluid type and the operating conditions (temperature and pressure). Common materials include stainless steel for corrosive fluids, cast iron for water applications, and PVC for chemical services.
Sealing Material: Ensure the sealing material (e.g., NBR, EPDM, Viton) is suitable for the fluid type and temperature.

5. Consider End Connections

Connection Type: Choose the appropriate end connection (flanged, threaded, wafer, socket weld, etc.) based on the piping system design and ease of maintenance.

6. Evaluate Special Requirements

Leakage: Determine the acceptable level of leakage, if any. Some systems may require a zero-leakage valve.
Orientation: Consider the installation orientation (horizontal, vertical flow up, vertical flow down) as it may affect the valve’s operation.
Pressure Drop: Minimize pressure drop by selecting a valve with an appropriate flow design.
Back Pressure: Ensure the system provides sufficient back pressure to close the valve properly.

7. Regulatory And Standards Compliance

Verify that the check valve meets any applicable industry standards (e.g., API, ASME, ANSI) and regulatory requirements for safety and performance.

8. Manufacturer And Warranty

Select a reputable manufacturer with proven experience in check valves for similar applications. Review warranty terms and post-sale support.

By systematically addressing these selection criteria, you can ensure that the chosen check valve will perform efficiently and reliably within your specific application, contributing to the overall safety and effectiveness of the piping system.

APPLICABLE SPECIFICATIONS (BS, API, ASME)

The key specifications that cover this type of valve are:

Check valves, critical components in various piping systems, are governed by numerous standards to ensure their reliability, safety, and performance. These standards, set by recognized bodies like the British Standards (BS), the American Petroleum Institute (API), and the American Society of Mechanical Engineers (ASME), specify design criteria, material specifications, testing requirements, and performance characteristics for check valves. Here’s a brief overview of some key BS, API, and ASME specifications applicable to check valves:

British Standards (BS)

BS 1868: Steel Check Valves for the Petroleum, Petrochemical, and Allied Industries
- Specifies requirements for steel check valves with flanged and butt-welding ends, designed for the petroleum, petrochemical, and allied industries. It covers valves of nominal sizes DN 50 to DN 600 and specifies body materials, pressure-temperature ratings, and testing.
BS EN 12334: Industrial Valves – Check Valves of Metallic Materials
- This European Standard specifies requirements for check valves made from metallic materials excluding steel and applies to check valves used for all industrial applications. It includes provisions for nominal sizes, pressure designations, and aspects of design, testing, and marking.
- American Petroleum Institute (API)
  - API 6D: Specification for Pipeline and Piping Valves
    
    While API 6D covers a broad range of pipeline valves, it includes specific requirements for check valves used in pipeline applications. It addresses aspects like design, materials, testing, and documentation for valves intended for use in the petroleum and natural gas industries.
  - API 594: Check Valves: Flanged, Lug, Wafer, and Butt-Welding
    
    API 594 is dedicated to check valves and covers design, materials, face-to-face dimensions, pressure-temperature ratings, and testing for check valves with flanged, lug, wafer, and butt-welding ends. It applies to types A (single plate) and B (double plate).
  - API 598: Valve Inspection and Testing
    
    While not specific to check valves, API 598 covers the inspection and testing of all types of valves, including check valves. It outlines the testing methods and acceptance criteria for pressure testing to ensure valve integrity and leak tightness.
  - API 620: Forged check valves
  American Society Of Mechanical Engineers (ASME)
  - ASME B16.34: Valves – Flanged, Threaded, and Welding End
    
    This standard establishes requirements for materials, pressure-temperature ratings, dimensions, tolerances, and markings for gate, globe, check, ball, and butterfly valves. It includes criteria that check valves must meet for design and construction.
  - ASME B16.10: Face-to-Face and End-to-End Dimensions of Valves
    
    ASME B16.10 specifies the face-to-face and end-to-end dimensions of valves, including check valves. This standard ensures compatibility and interchangeability in valve replacements and installations.
  - ASME B16.25: Buttweld ends
  Adherence to these BS, API, and ASME specifications is essential for the proper selection, installation, and maintenance of check valves in various industrial applications. Compliance with these standards guarantees that check valves meet the necessary quality, safety, and performance requirements for their intended use.
  
  CHECK VALVE TYPES
  Check valves, essential components in preventing backflow in piping systems, come in various designs to accommodate different flow dynamics, pressure conditions, and installation requirements. Here’s a detailed explanation of the different types of check valves:
  SWING CHECK VALVE
  
  Swing check valves are a type of non-return valve used in piping systems to prevent backflow. They operate automatically, allowing fluid to flow through in one direction and preventing reverse flow. The design and operation of swing check valves make them suitable for a wide range of applications, particularly where low-pressure drop and self-acting backflow prevention are required.
  
  Swing Check Valve Design
  
  The primary components of a swing check valve include:
  - Body: The outer casing of the valve, which contains the internal components. It can be made from various materials, including cast iron, steel, stainless steel, and PVC, depending on the application requirements.
  - Disc: A movable door-like element that swings on a hinge or a shaft. The disc opens with forward flow and swings back to its closed position when the flow stops or reverses, blocking the flow.
  - Seat: The surface against which the disc seals when the valve is closed. The seat can be integral to the valve body or replaceable, and it is often designed to ensure a tight seal to prevent backflow.
  - Hinge or Shaft: Enables the swinging motion of the disc. In some designs, a lever and weight or spring mechanism may be added to assist in closing the valve more rapidly or controlling the swing to reduce the water hammer.
  Operation
  
  In operation, the pressure of the forward flow pushes the disc open, allowing fluid to pass through the valve. When the flow stops or reverses, the disc swings back to its closed position, either due to gravity or assisted by a lever and weight mechanism, preventing backflow. The simplicity of this mechanism ensures reliability and minimal maintenance.
  
  Advantages
  - Low-Pressure Drop: When fully open, swing check valves provide a relatively straight flow path, resulting in a low-pressure drop across the valve.
  - Simple and Reliable: The design is straightforward, with few moving parts, contributing to the valve’s reliability and ease of maintenance.
  - Versatility: Suitable for a wide range of fluids, including water, oil, and gas, and can be used in various applications, from low to high-pressure systems.
  Applications
  
  Swing check valves are commonly used in:
  - Water Supply Systems: To prevent backflow and protect equipment like pumps.
  - Wastewater Treatment: Where preventing reverse flow is crucial for process integrity.
  - Industrial Processes: In chemical, petrochemical, and other industrial plants where backflow prevention is necessary.
  Considerations
  
  While swing check valves are suitable for many applications, proper selection involves considering factors like the risk of water hammer (sudden closing can lead to pressure surges), the need for rapid closure, and the compatibility of valve materials with the fluid. Additionally, they are not recommended for pulsating flows as the constant opening and closing may lead to premature wear or failure.
  
  In summary, swing check valves offer a simple, efficient solution for preventing backflow in piping systems, combining low-pressure drop with reliable operation across a broad range of applications.
  
  STOP CHECK VALVE
  
  Stop check valves are specialized valves that combine the features of a check valve and a globe valve, offering both backflow prevention and the ability to manually stop the flow of fluid in a piping system. They provide a unique functionality that allows operators to control the valve’s position, acting as a check valve when left to operate automatically or as an isolation valve when manually adjusted.
  
  Design Of Stop Check Valves
  
  The key components of a stop check valve include:
  - Body: The outer casing that houses the valve’s internal mechanisms. It can be made of various materials suited to the application’s needs, such as cast iron, stainless steel, or other alloys.
  - Disc: A movable element that lifts away from the valve seat to allow flow in one direction and seats back to block flow in the opposite direction. Unlike standard check valves, the disc in a stop check valve can also be manually positioned to fully close, regardless of flow direction.
  - Stem: Connected to the disc, the stem can be moved manually (e.g., via a handwheel or actuator) to lift the disc from the seat or to firmly press it against the seat, effectively stopping flow.
  - Seat: The area against which the disc seals to prevent backflow or to stop flow entirely when the valve is manually closed.
  - Bonnet: The top part of the valve that contains the stem and, in some designs, may house packing material to prevent leaks along the stem.
  Operation
  
  In its default mode, a stop check valve functions as a check valve, allowing flow in one direction and automatically preventing backflow by seating the disc against the valve seat under reverse flow conditions. However, the key feature of a stop check valve is its ability to be manually closed by an operator, overriding the automatic function. This is accomplished by turning the handwheel or actuator, which moves the stem and disc into a closed position against the seat, regardless of flow direction or pressure.
  
  Advantages
  - Dual Functionality: Provides the benefits of a check valve and a globe valve in a single unit, offering flexibility in applications that require both backflow prevention and flow isolation.
  - Manual Override: The ability to manually stop flow, irrespective of system pressure or flow direction, enhances control over the system.
  - Safety and Protection: Helps protect against reverse flow that could damage equipment, while also allowing for system maintenance by isolating parts of the system.
  Applications
  
  Stop check valves are commonly used in high-pressure and high-temperature applications, such as:
  - Boilers: To prevent the backflow of water or steam that could damage the boiler or other equipment in steam systems.
  - Power Generation: In feedwater lines, to control flow to steam generators and allow for system isolation for maintenance.
  - Process Industries: Where process safety requires both the prevention of backflow and the ability to isolate sections of the system for maintenance or emergency shutdowns.
  Considerations
  
  When selecting a stop check valve, it’s essential to consider the fluid characteristics, pressure and temperature conditions, and the specific requirements for flow control and isolation. Additionally, like all valves, regular maintenance is necessary to ensure reliability, especially given the critical safety functions these valves often serve.
  
  In summary, stop check valves offer a versatile solution for systems requiring both backflow prevention and the capability to manually stop flow, making them invaluable in various industrial applications where safety, control, and maintenance are paramount.
  BALL CHECK VALVE
  A ball check valve is a type of check valve that uses a ball to prevent backflow in a piping system. It operates automatically, allowing fluid to flow through it in one direction and preventing reverse flow by utilizing a ball that moves within the valve body. Ball check valves are simple, reliable, and effective for a wide range of applications, particularly where viscous fluids or fluids with suspended solids are present.
- Design
  
  The key components of a ball check valve include:
  - Body: The outer casing of the valve, which can be made from various materials such as cast iron, stainless steel, PVC, or other corrosion-resistant alloys, depending on the fluid characteristics and application requirements.
  - Ball: The movable element inside the valve that seals against reverse flow. The ball is typically made of metal, rubber, or plastic. Its material and density are chosen based on the fluid type and the required sealing capability.
  - Seat: The surface inside the valve body against which the ball seals when the valve is closed. The seat is often designed to match the contour of the ball for a tight seal and can be made from materials similar to or compatible with the ball.
  - Cover or Bonnet: A removable part that provides access to the interior of the valve for maintenance, inspection, or replacement of the ball and seat.
  Operation
  
  In operation, forward fluid pressure pushes the ball away from the seat, allowing fluid to flow through the valve. When the fluid flow stops or reverses direction, the ball rolls or is pushed back against the seat by the reverse flow, effectively sealing the valve and preventing backflow. In some designs, a spring or external weight may assist in closing the valve, especially in horizontal installations where gravity alone may not be sufficient to seal the valve.
  
  Advantages
  - Versatility: Effective for a broad range of fluids, including liquids and gases, and particularly suitable for viscous fluids and slurries.
  - Low Maintenance: The simple design has few moving parts, reducing the risk of malfunction and the need for maintenance.
  - Durability: When made with appropriate materials, ball check valves can be highly durable and resistant to wear and corrosion.
  - Self-Cleaning: The rolling action of the ball can help dislodge small particles, preventing clogging and ensuring reliable operation.
  Applications
  
  Ball check valves are used in various applications, including:
  - Wastewater and Sewage Systems: For preventing backflow in sewage lines and treatment facilities.
  - Chemical Processing: In systems handling viscous chemicals or fluids with suspended solids.
  - Pumping Systems: To prevent reverse flow and protect pumps in water, oil, and other liquid transfer systems.
  - Agricultural Irrigation: In irrigation systems to maintain water flow direction and prevent contamination.
  Selection Considerations
  
  When selecting a ball check valve, consider:
  - Fluid Characteristics: Ensure compatibility with the valve materials to prevent corrosion or degradation.
  - Pressure and Temperature: Choose a valve rated for the system’s maximum pressure and temperature conditions.
  - Installation Orientation: While ball check valves are versatile, confirm the valve’s suitability for the intended orientation, especially in horizontal lines.
  - Valve Sizing: Proper sizing is crucial to minimize pressure drop while ensuring effective backflow prevention.
  Ball check valves offer a practical solution for preventing backflow in a wide range of applications. Their simplicity, reliability, and effectiveness make them a preferred choice in systems where maintenance should be minimal, and fluid characteristics are challenging.
  
  Ball check valves belong to the family of “lift valves”, and have a seat design similar to globe valves.
- A variant of the ball design is the so-called piston type. This type of valve is used for high-pressure services where the fluid can change direction suddenly and with good force (this because the disc is precisely guided and fits perfectly into the seat).
  Ball and piston check valves can be installed both horizontally and vertically.
  
  DUAL PLATE CHECK VALVE
  
  A dual plate check valve, also known as a double door check valve or a butterfly check valve, is an advanced design of the traditional check valve. It operates automatically to prevent the backflow of fluid in a piping system, ensuring flow in only one direction. The valve features two spring-loaded plates (or discs) that open with forward flow and close rapidly to prevent reverse flow, making it an efficient and reliable choice for a wide range of applications.
  
  Design
  
  The key components and design features of a dual plate check valve include:
  - Body: The outer shell of the valve that houses the internal components. It can be made from various materials, including cast iron, stainless steel, carbon steel, and other alloys, depending on the application’s specific requirements for pressure, temperature, and corrosion resistance.
  - Plates (Discs): Two semi-circular plates are hinged on either side of the valve body, allowing them to swing open or close. The plates are typically lightweight, enhancing their ability to respond quickly to changes in flow direction.
  - Springs: Each plate is equipped with a spring that facilitates quick closing of the plates when the forward flow stops or when there is a reversal in flow direction. The springs help in minimizing the risk of water hammer and valve slam.
  - Seat: A sealing surface inside the valve body against which the plates close. The seat can be integral to the valve body or replaceable and is designed to ensure a tight seal when the valve is closed.
  - Hinge Pins: Pins around which the plates pivot. They are designed to ensure smooth and reliable operation of the plates.
  Operation
  
  In operation, forward flow exerts pressure on the plates, causing them to swing open and allow fluid to pass through the valve. The design of the plates and the presence of springs ensure that they open with minimal pressure drop. When the flow decreases or reverses, the springs assist in quickly closing the plates, preventing backflow. The rapid response of the plates helps to significantly reduce the potential for water hammer.
  
  Advantages
  - Compact and Lightweight: Dual plate check valves are more compact and lighter than traditional swing check valves, making them easier to install and requiring less support structure.
  - Low-Pressure Drop: The design allows for a smoother flow path when open, resulting in a lower pressure drop compared to other types of check valves.
  - Quick Closure: The spring-loaded plates close rapidly, reducing the risk of water hammer and backflow.
  - Versatility: Suitable for a wide range of applications and can be installed in both horizontal and vertical orientations with upward flow.
  Applications
  
  Dual plate check valves are used in various industrial applications, including:
  - Water and Wastewater Treatment: To prevent backflow in treatment plants and distribution systems.
  - Oil and Gas: In pipelines and processing facilities for protecting equipment and ensuring unidirectional flow.
  - HVAC Systems: To prevent reverse flow in heating and cooling systems.
  - Process Industries: In chemical, petrochemical, and food and beverage processing plants to protect sensitive equipment and maintain process integrity.
  Selection Considerations
  
  When selecting a dual plate check valve, it’s important to consider:
  - Fluid Characteristics: Compatibility with the valve materials to prevent corrosion and ensure durability.
  - Operating Conditions: The valve’s rating must match the system’s maximum pressure and temperature.
  - Installation Space: The compact design is advantageous in tight spaces, but the orientation and location should still be considered for optimal performance.
  - Maintenance Requirements: Though generally low maintenance, access for inspection or replacement of components should be considered.
  In summary, dual plate check valves offer an efficient and reliable solution for preventing backflow in piping systems, combining compact design with quick operation and low-pressure drop. Their versatility and performance advantages make them suitable for a broad range of applications across various industries.
  
  TITLING DISC CHECK VALVE
  
  A tilting disc check valve is a type of check valve designed to allow fluid to flow in one direction and prevent backflow. It features a disc that tilts on a hinge or pivot point, opening in response to forward flow and closing when the flow stops or reverses. This design offers improved dynamics over traditional swing check valves, making it particularly effective in applications where rapid closure is needed to prevent reverse flow and minimize the risk of water hammering.
  
  titling disc check valve
  
  Design Features
  - Disc Mechanism: The disc in a tilting disc check valve is mounted such that it tilts around a point or axis that is offset from the center of the disc. This allows the disc to open with a smaller amount of fluid pressure compared to swing check valves and to close more quickly as the flow diminishes.
  - Seat: The valve seat is designed to provide a tight seal when the disc closes. The seating arrangement can be configured to reduce wear and enhance the sealing capability.
  - Body: The valve body can vary in design but is typically streamlined to facilitate smooth fluid flow and minimize pressure drop across the valve.
  Operational Advantages
  - Quick Response: The tilting mechanism allows for rapid opening and closing of the valve, which helps in preventing the backflow more effectively and reduces the potential for water hammer, a pressure surge caused when a fluid in motion is forced to stop or change direction suddenly.
  - Low-Pressure Drop: When open, the valve offers minimal obstruction to the flow, resulting in a lower pressure drop compared to some other check valve designs.
  - Long Service Life: The design of the tilting disc check valve, including the way the disc interacts with the flow, can contribute to reduced wear on the valve components, leading to a longer service life.
  Applications
  
  Tilting disc check valves are suitable for a wide range of applications, particularly in systems where rapid valve closure is necessary to protect equipment and ensure system integrity. Common applications include:
  - Water Supply Systems: Used in high-rise buildings and municipal water distribution networks to prevent backflow.
  - Power Generation: Installed in cooling water systems, feedwater systems, and condensate pump discharge lines to prevent reverse flow.
  - Process Industries: Utilized in chemical and petrochemical plants, where the prevention of backflow is critical to process safety and efficiency.
  - HVAC Systems: Implemented heating and cooling systems to maintain directional flow and system balance.
  Selection Considerations
  
  When selecting a tilting disc check valve, consider the following:
  - Fluid Characteristics: Ensure the valve materials are compatible with the fluid, including considerations for temperature, pressure, and potential corrosiveness.
  - Installation Orientation: While versatile, the specific design of the tilting disc check valve may make it more suitable for certain orientations. Consult manufacturer recommendations.
  - Maintenance Requirements: Consider the ease of maintenance and access to internal components, as regular inspection may be necessary to ensure optimal performance.
  Tilting disc check valves offer an efficient solution for preventing backflow in fluid systems, combining quick response, durability, and effective operation across a variety of applications.
- FOOT CHECK VALVE
  
  A foot check valve is a specific type of check valve designed to be installed at the bottom of a pump suction line, primarily used to maintain the pump’s prime by preventing the backflow of fluid. These valves are typically submerged in the source fluid, such as a well or a tank. Foot check valves are essential components in pumping systems where the pump is located above the fluid level, ensuring a steady and reliable supply of fluid to the pump and preventing the system from running dry.
  
  foot check valve
  
  Design Features
  - Body: Foot check valves are commonly made from durable materials such as cast iron, stainless steel, PVC, or bronze, depending on the application and the type of fluid being handled.
  - Screen or Strainer: A key feature of foot check valves is the integrated screen or strainer at the inlet. This screen prevents debris, sediment, and other particulates from entering the pump suction line, protecting the pump and the system from damage.
  - Valve Mechanism: The valve mechanism can vary but often includes a ball, disc, or flap that opens under the pressure of incoming fluid when the pump operates. When the pump stops, the mechanism seals against a seat to prevent fluid from flowing backward.
  Operational Advantages
  - Maintains Prime: By preventing the backflow of fluid, foot check valves help maintain the pump’s prime, which is crucial for efficient pump operation and to avoid pump damage due to dry running.
  - Filtration: The built-in screen or strainer filters out debris, ensuring that the fluid entering the pump is free from particulates that could cause wear or clogs.
  - Versatility: Suitable for a wide range of applications, including water, chemicals, and other fluids, depending on the construction materials.
  Applications
  
  Foot check valves are used in various applications where pumps need to draw fluid from a source below the pump, such as:
  - Water Supply Systems: In wells, cisterns, or tanks where pumps supply water to residential, agricultural, or industrial systems.
  - Irrigation Systems: To ensure a constant supply of water and prevent contamination of the water source by soil or debris.
  - Flood Control and Drainage: In pumping stations that remove water from low-lying areas.
  - Industrial Processes: Where liquid ingredients or products are transferred from storage tanks into processing systems.
  Selection Considerations
  
  When choosing a foot check valve, it’s essential to consider:
  - Fluid Compatibility: Select materials that are compatible with the fluid to prevent corrosion or chemical degradation.
  - Screen Mesh Size: The mesh size of the screen should be suitable for filtering out debris while allowing sufficient flow to meet the system’s demands.
  - Pressure and Flow Requirements: Ensure the valve can handle the system’s pressure and flow rate without causing excessive pressure drop or hindering pump performance.
  - Maintenance Accessibility: Consider how easily the valve can be accessed for cleaning or maintenance, especially since foot check valves are often submerged.
  In summary, foot check valves play a critical role in pumping systems, providing both a non-return function to maintain the pump prime and a filtration role to protect the pump and the system. Their selection and maintenance are vital for the reliability and efficiency of fluid transfer operations.
  
  PRESSURE SEAL CHECK VALVE
  
  Pressure seal check valves are a type of check valve designed for high-pressure and high-temperature applications, commonly found in power generation, oil and gas, and industrial process systems. Unlike traditional bolted bonnet check valves, pressure seal check valves use a pressure seal bonnet design that ensures a tighter seal as system pressure increases. This design is particularly effective in environments where safety and efficiency are paramount, and where operating conditions can exceed pressures of 600 psi and temperatures above 1000°F (538°C).
- Design
  
  The key components of a pressure seal check valve include:
  - Body: The main structure that contains the internal components. It can be made of materials suited for high pressure and temperature, such as carbon steel, alloy steel, or stainless steel.
  - Bonnet: Instead of being bolted to the body, the bonnet in a pressure seal valve is sealed using a pressure seal gasket. As system pressure rises, the gasket is further compressed, enhancing the seal between the bonnet and the valve body.
  - Pressure Seal Gasket: A unique component of pressure seal valves, this gasket is usually made of flexible graphite for high-temperature applications or metal for extremely high pressures. It is designed to ensure a tight seal that improves with increased pressure.
  - Disc: The movable part that opens to allow flow in the forward direction and seats against the valve seat to prevent backflow. The design of the disc can vary but typically mirrors that of swing or lift check valves.
  - Seat: The surface against which the disc seals when the valve is closed. It can be integral to the valve body or replaceable, depending on the design.
  Operation
  
  In operation, forward flow pressure pushes the disc away from the seat, allowing fluid to pass through the valve. When flow stops or reverses, the disc moves back to the seat, preventing backflow. The unique pressure seal design ensures that as system pressure increases, the seal between the bonnet and the body becomes tighter, which is particularly advantageous in high-pressure applications where ensuring a reliable seal is challenging.
  
  Advantages
  - High-Pressure and Temperature Capability: Designed to operate reliably in conditions where standard check valves might fail, making them ideal for critical applications.
  - Improved Seal Integrity: The pressure seal design ensures that the valve’s sealing capability improves under higher pressures, providing a robust solution for high-pressure systems.
  - Compact Design: Pressure seal valves tend to be more compact than their bolted bonnet counterparts, beneficial in systems where space is limited.
  Applications
  
  Pressure seal check valves are used in applications that demand reliable operation under high pressure and temperature, such as:
  - Power Generation: In steam, feedwater, and other high-pressure systems within power plants.
  - Oil and Gas Production: For high-pressure drilling and production systems.
  - Chemical Processing: In processes involving high-pressure reactions or transfers.
  Selection Considerations
  
  When selecting a pressure seal check valve, consider:
  - System Pressure and Temperature: Ensure the valve material and design are rated for the system’s maximum operating pressure and temperature.
  - Fluid Compatibility: Choose materials that are compatible with the fluid to prevent corrosion or degradation of the valve components.
  - Maintenance Requirements: While durable, pressure seal valves can be more challenging to maintain due to their design. Consider ease of maintenance and access when selecting a valve.
  Pressure seal check valves offer a reliable solution for controlling flow in high-pressure and high-temperature systems, ensuring safety and efficiency in demanding industrial environments.
  DUCKBILL CHECK VALVE
  
  A duckbill check valve is a unique type of check valve that gets its name from the duckbill-shaped flexible rubber or elastomer flap that acts as the valve mechanism. This design allows the valve to permit fluid flow in one direction while preventing backflow in the opposite direction. Duckbill check valves are known for their simplicity, reliability, and low maintenance, making them an excellent choice for various fluid control applications, especially where backflow prevention is critical.
  
  Duckbill Valve
  
  IN-LINE CHECK VALVE
  
  An inline check valve, also known as an in-line check valve, is a type of check valve designed for simple, direct installation within the pipeline. Its primary function is to allow fluid (liquid or gas) to flow in one direction only, preventing backflow which could potentially cause damage or disrupt the operation of a system. Inline check valves are known for their compact design, which makes them particularly suitable for applications with limited space.
  
  Inline Check Valve
  
  Design Features
  - Compact and Simple: Inline check valves have a straightforward and compact design, allowing for easy installation directly into a piping system without the need for special fittings or extensive modifications.
  - Body Construction: The valve body is typically cylindrical and can be made from a variety of materials, including metals like brass, stainless steel, and PVC, to suit different application needs and fluid compatibility.
  - Closure Mechanism: The closure component inside an inline check valve varies by design but commonly includes a ball, disc, or piston that moves away from the valve seat to allow flow and seals against the seat to prevent backflow. Some designs use a spring to ensure the closure mechanism responds quickly to changes in flow direction.
  - Connection Types: Inline check valves are available with various types of end connections, such as threaded, socket weld, or flanged, to match the piping system requirements.
  Operational Advantages
  - Low Pressure Drop: Many inline check valve designs are optimized to minimize pressure drop across the valve when it is in the open position, maintaining system efficiency.
  - Fast Response to Flow Changes: The simplicity of the design often allows for a quick response to stopping backflow, protecting the system from potential damage.
  - Versatility: Inline check valves can be used in a wide range of applications and are compatible with many types of fluids and gases.
  Applications
  
  Inline check valves are used across various industries and applications, including:
  - Water and Wastewater Systems: To prevent backflow and protect pumps and other equipment.
  - Chemical Processing: For ensuring unidirectional flow of chemicals in processing lines.
  - HVAC Systems: In heating and cooling lines to maintain proper flow direction.
  - Hydraulic and Pneumatic Systems: To prevent reverse flow in systems that rely on pressurized fluids or air.
  Selection Considerations
  
  When selecting an inline check valve, consider the following:
  - Material Compatibility: Choose a valve material that is compatible with the fluid or gas to prevent corrosion or chemical degradation.
  - Operating Conditions: Ensure the valve can withstand the system’s pressure and temperature conditions.
  - Flow Requirements: Select a valve size and design that meets the flow rate requirements without causing excessive pressure drop.
  - Maintenance and Accessibility: Consider how the valve design will impact maintenance needs and whether it can be easily accessed for service if necessary.
  Inline check valves offer a convenient and efficient solution for ensuring unidirectional flow in piping systems. Their compact design, ease of installation, and reliability make them a popular choice for many applications where backflow prevention is critical.
  
  SUMP PUMP CHECK VALVE
  
  A sump pump check valve is a critical component in a sump pump system, designed to prevent the backflow of water from the discharge pipe back into the sump pit after the pump has turned off. Sump pumps are commonly used in basements and crawl spaces to remove accumulated water, preventing flooding and water damage. The check valve ensures that once water is pumped out of the pit and through the discharge line, it does not return, thereby enhancing the efficiency of the pump and reducing the risk of flooding.
  
  Design
  
  The design of a sump pump check valve is relatively simple, comprising a few key components:
  - Body: Usually made of durable plastic, PVC, or sometimes metal, designed to withstand the water pressure and any debris that might be present in the water.
  - Flapper or Ball: The mechanism inside the valve that allows water to flow in one direction and blocks it from flowing backward. In sump pump check valves, a flapper or a ball is common, which moves or tilts to open when water is pumped through and seals shut when the flow stops.
  - Connectors: Ends that attach to the discharge pipe of the sump pump and the discharge line leading away from the house. These can be designed for various types of connections, including threaded, slip-on, or barbed, depending on the installation requirements.
  Operation
  
  When the sump pump activates, water pressure opens the flapper or moves the ball, allowing water to pass through the valve and into the discharge line. When the pump shuts off, the decrease in pressure allows the flapper or ball to return to its closed position, creating a seal that prevents water from flowing back into the sump pit. This one-way operation is crucial for maintaining the effectiveness of the sump pump system and preventing cycling (where the pump turns on and off frequently), which can lead to premature pump failure.
  
  Advantages
  - Prevents Backflow: Keeps pumped water from returning to the sump pit, reducing the workload on the sump pump and minimizing wear.
  - Reduces Cycling: By preventing backflow, it reduces the frequency of pump activation, thereby extending the life of the pump.
  - Simple Installation: Most sump pump check valves are designed for easy installation and can be added to existing systems without significant modifications.
  Applications
  
  Sump pump check valves are used in residential, commercial, and industrial settings where sump pumps are installed to control water accumulation. These include:
  - Basements and Cellars: To prevent flooding from groundwater or stormwater intrusion.
  - Crawl Spaces: To manage moisture and prevent water damage.
  - Outdoor Drainage Systems: Where pumps are used to move water away from buildings or sensitive areas.
  Selection Considerations
  
  When choosing a sump pump check valve, consider:
  - Compatibility: Ensure the valve fits the discharge pipe diameter of your sump pump system.
  - Material: Select a material compatible with the type of water being pumped, especially if debris or chemicals may be present.
  - Valve Type: Consider the mechanism (flapper vs. ball) based on the pump’s flow rate and the head pressure.
  - Ease of Maintenance: Some designs allow for easier cleaning and maintenance, which can be beneficial in systems that handle debris-laden water.
  In summary, a sump pump check valve is an essential component that enhances the efficiency and longevity of a sump pump system by preventing backflow of water into the sump pit, ensuring that once water is removed, it stays out.
  CHECK VALVE MATERIALS (ASME, API)
  
  Materials used for check valves in various industries, particularly those handling critical processes, need to meet specific standards to ensure reliability, safety, and longevity. The American Society of Mechanical Engineers (ASME) and the American Petroleum Institute (API) provide guidelines and standards for materials used in the manufacturing of check valves. These standards help in selecting materials that are suitable for the intended application, especially considering the operational pressures, temperatures, and fluid characteristics. Below are some key materials standards from ASME and API relevant to check valves:
  
  ASME Material Standards
  - ASME B16.34 – Valves – Flanged, Threaded, and Welding End
    
    This standard covers material requirements for ferrous and non-ferrous valve construction, including temperature and pressure ratings for various materials. It is widely referenced for valve materials in piping systems.
  API Material Standards
  - API 600 – Steel Gate Valves – Flanged and Butt-Welding Ends, Bolted Bonnets
    
    Though primarily focused on gate valves, API 600 includes material specifications applicable to check valves, especially regarding carbon steel, alloy steel, stainless steel, and other materials for high-pressure and high-temperature service.
  - API 602 – Compact Steel Gate Valves – Flanged, Threaded, Welding, and Extended-Body Ends
    
    This standard, while focusing on gate valves, also touches on material specifications for smaller size valves that can be relevant to compact check valves in similar service conditions.
  Common Materials For Check Valves
  - Carbon Steel: Widely used due to its strength and durability, suitable for a broad range of temperatures and pressures. ASME and API standards specify different grades, such as ASTM A216 WCB, for various service conditions.
  - Stainless Steel: Offers excellent corrosion resistance and is used in applications involving corrosive fluids or stringent cleanliness requirements. Common grades include ASTM A351 CF8M (316 stainless steel).
  - Alloy Steel: Used for applications requiring higher strength and resistance to high temperatures or pressures. Alloys like ASTM A217 WC6 are commonly specified for services with elevated temperatures.
  - Bronze and Brass: Offer good corrosion resistance and are commonly used in low to moderate temperature and pressure applications, such as water, gas, and some chemical services.
  - Ductile Iron: Provides good strength, durability, and some corrosion resistance, making it suitable for water and other non-corrosive services at lower costs than steel.
  Considerations For Material Selection
  1. Fluid Service: The material must be compatible with the fluid to prevent corrosion or degradation that could lead to valve failure.
  2. Pressure and Temperature: The material should withstand the maximum expected pressure and temperature in the system.
  3. Environment: External environmental conditions, such as exposure to corrosive atmospheres, should also be considered.
  By adhering to ASME and API material standards, engineers and specifiers can ensure that check valves will perform reliably and safely in their intended applications, maintaining system integrity and protecting against failure.
  
  CHECK VALVE TRIM
  Check valve trim refers to the internal components of a check valve that come into direct contact with the process fluid and are critical to the valve’s operation and performance. The trim typically includes parts such as the disc (or ball), seat, stem (if applicable), and any springs or other mechanisms that contribute to the opening and closing of the valve. The material selection and design of the check valve trim are crucial for ensuring proper function, durability, and compatibility with the fluid being handled.
  
  Components Of Check Valve Trim
  
  Disc or Ball: The movable part that seals against the seat to prevent backflow. In ball check valves, a ball acts as the movable element, whereas other types of check valves may use a disc or other shapes.
  
  Seat: The surface against which the disc or ball seals when the valve is closed. It can be integrated into the valve body or designed as a replaceable component. The seat must provide a tight seal to effectively prevent backflow.
  
  Stem: In some types of check valves, such as lift check valves, a stem connects the disc to an actuator or mechanism outside the valve body. The stem facilitates the movement of the disc within the valve.
  
  Spring: Many check valves incorporate a spring to assist in closing the valve, ensuring quick response to flow changes and helping to prevent flow reversal and water hammer.
  
  Material Considerations
  
  The choice of materials for check valve trim is determined by factors such as:
  
  Fluid Compatibility: The trim materials must be chemically compatible with the process fluid to avoid corrosion, degradation, or contamination.
  
  Operating Conditions: The materials must withstand the temperature and pressure conditions of the application without losing structural integrity or performance.
  
  Wear Resistance: Components like the disc and seat are subject to wear due to repeated opening and closing; thus, materials should be selected for their durability and wear resistance.
  
  Common materials used for check valve trim include:
  
  Stainless Steel: Offers excellent corrosion resistance and strength, suitable for a wide range of applications.
  
  Brass: Commonly used in low-pressure applications and compatible with many types of fluids.
  
  Bronze: Provides good corrosion resistance and is often used in water and steam applications.
  
  Alloy Steels: Selected for high-pressure, high-temperature applications where additional strength and durability are required.
  
  Plastics and Composites: Used in applications where corrosion resistance is paramount, such as in aggressive chemical environments.
  
  Selection Guidelines
  
  When selecting check valve trim materials, consider the following:
  
  Review Fluid Service: Analyze the chemical properties of the fluid, including any potential for corrosion or chemical reaction.
  
  Assess Operating Conditions: Ensure the materials can handle the maximum expected temperature and pressure.
  
  Consider Flow Characteristics: For applications involving abrasive or viscous fluids, select materials that resist wear and erosion.
  
  Compliance with Standards: Ensure that the materials meet relevant industry standards and regulations, such as those set by ASME, API, or NACE for specific applications.
  
  Choosing the appropriate trim materials is essential for the reliability and longevity of check valves, ensuring they function correctly under the intended service conditions and minimize maintenance requirements.
  CHECK VALVE GA DIAGRAM
  
  he body of non-return valves below 2 inches is generally made of forged steel (common grades are ASTM A105 for high-temperature service, ASTM A350 for low-temperature service, and, ASTM A182 F304/F316 for corrosive service), whereas the bodies for larger bore sizes check valves are made of cast steel (ASTM A216 WCB for high-temperature service, ASTM A351 for low-temperature conditions and ASTM A351 CF8 and CF8M – i.e. SS304 and SS316).

May 23, 2024/by stvvalve

industry valve news, News

Understand Globe Valves (BS 1873 & API 602)

What is a globe valve? When shall it be used instead of gate and ball valves? In this article, we illustrate the scope of this type of valve (which is, in a word, to regulate the flow), the differences with other types of valve, the alternative designs, and specifications (BS 1873 for the cast steel and API 602/BS 5352 for the forged steel type).

GLOBE VALVE

WHAT IS A GLOBE VALVE?

Definition Of Globe Valve

A globe valve is a type of valve used for regulating flow in a pipeline, or to shut off the flow, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body (even if for shut-off operations ball valves and gate valves shall always be preferred).

The term “globe” comes from the valve’s spherical body shape, though the actual shape can vary, especially in modern designs. The key function of a globe valve is to start, stop, or throttle the flow of fluid through a pipeline; it achieves this through the precise positioning of the disk against the valve seat, which forms a gap allowing the fluid to pass through in a controlled manner.

Globe valves are bi-directional valves, different from check valves, meaning that the fluid can flow either way within the valve.

Globe valves offer a reliable solution for flow control applications, combining good sealing capabilities with the ability to precisely regulate flow. Their versatility and efficiency make them a valuable component in various piping systems.

Design And Operation

The basic components of a globe valve include the body, seat, stem, disc, and handwheel or actuator. The valve’s operation is straightforward:

Turning the handwheel or activating the actuator moves the stem and the attached disc toward or away from the seat.
When the disc moves towards the seat, it restricts the flow path, reducing flow or stopping it completely when fully closed.
Moving the disc away from the seat opens the flow path, allowing fluid to pass through.

Key Features

Flow Regulation: Globe valves excel at regulating flow rates due to their design, which allows for fine adjustments of the disc position.
Sealing Capability: The close contact between the disc and seat provides good sealing capabilities, minimizing leaks when the valve is closed.
Directional: Typically, globe valves are used in applications where the flow direction is important, as they are designed to handle flow in one direction, which helps in reducing pressure drop and preventing backflow.

Applications

Globe valves are used across various industries where flow needs to be precisely controlled, including:

Water and Wastewater Management: For regulating flow and pressure within distribution networks.
HVAC Systems: In heating and cooling systems for controlling the flow of hot or cold water.
Chemical and Petrochemical Industries: For managing the flow of various chemicals in processing plants.
Steam Services: Such as in power plants, where steam flow must be carefully controlled.

Globe Valves Selection Considerations

Selecting the right globe valve for your application involves careful consideration of various factors to ensure optimal performance, reliability, and safety. Globe valves are used for regulating flow in a piping system, and the correct selection is crucial for effective system operation. Here’s a detailed guide on how to select a globe valve:

1. Understand The Application

Fluid Characteristics: Identify the type of fluid (liquid, gas, corrosive, toxic, etc.) the valve will handle. This determines the material selection for the valve body, trim, and sealing components.
Pressure and Temperature: Determine the operating pressure and temperature range. This information is crucial for selecting a valve that can withstand the system’s conditions without failure.
Flow Requirements: Consider the flow rate and the necessity for flow regulation or throttling. Globe valves offer excellent throttling capabilities, but the degree of control required will influence the valve design.

2. Select The Proper Valve Size

Pipe Size: The valve size should correspond to the pipe size in the system to ensure proper fit and avoid unnecessary pressure drops.
Cv Value: Calculate the valve’s flow coefficient (Cv) required based on the flow rate, fluid density, and the pressure drop across the valve. The Cv value helps in selecting a valve size that meets the flow requirements without excessive pressure loss.

3. Choose The Valve Body Material

Compatibility: The valve material must be compatible with the fluid to prevent corrosion. Common materials include carbon steel, stainless steel, bronze, and special alloys for corrosive applications.
Temperature and Pressure: The material must also be suitable for the operating temperature and pressure. Refer to ASTM, ASME, and other relevant standards for guidance on material properties under specific conditions.

4. Determine The Valve End Connections

Connection Type: Globe valves are available with flanged, threaded, butt-weld, and socket-weld end connections. The choice depends on the piping system design, pressure rating, and ease of installation or maintenance.
Standards Compliance: Ensure the selected end connections comply with industry standards, such as ASME B16.5 for flanged connections, to ensure compatibility and integrity in the piping system.

5. Select The Appropriate Trim Material

Service Conditions: The trim (disc, seat, and stem) material should be selected based on the fluid type, pressure, temperature, and potential for wear or corrosion. The trim material may differ from the body material to optimize performance and lifespan.
Leakage Class: Consider the required leakage class based on system requirements. Different trim designs offer varying levels of sealing efficiency, affecting the valve’s ability to completely shut off or precisely regulate flow.

6. Actuation Method

Manual vs. Automated: Decide between manual operation (handwheel or gear operator) and automated actuation (pneumatic, hydraulic, or electric). Automated actuators are preferred for remote control, frequent operation, or where precise control is needed.
Actuator Sizing: Ensure the actuator is properly sized to operate the valve under all expected conditions, including the maximum differential pressure.

7. Consider Special Features

Bellows Seal: For toxic or hazardous fluids, consider a globe valve with a bellows seal to prevent stem leakage.
Cage Guided: Cage-guided trims provide stability to the plugin in high-flow conditions, reducing vibration and wear.

8. Compliance And Certifications

Ensure the globe valve meets relevant industry standards and certifications for safety, performance, and quality. Common standards include ASME, API, and ANSI specifications relevant to globe valves.

9. Consult With Manufacturers Or Experts

When in doubt, consult with valve manufacturers or industry experts. They can provide valuable insights and recommendations based on experience with similar applications.

Selecting the right globe valve is a process that requires an understanding of the application requirements, knowledge of valve design principles, and consideration of the operating environment. By systematically addressing these factors, you can ensure the selected globe valve will perform efficiently and reliably in your system.

GLOBE VALVE ADVANTAGES AND DISADVANTAGES

Globe valves, recognized for their ability to regulate flow in piping systems, come with a set of advantages and disadvantages that make them suitable for specific applications while less ideal for others. Understanding these pros and cons is essential for selecting the right valve type for a particular system requirement.

Advantages Of Globe Valves

Precise Flow Control: One of the primary advantages of globe valves is their exceptional capability to regulate flow. The design allows for fine adjustments of the disc position, providing superior control over the flow rate.
Good Sealing Capability: Globe valves offer a tight seal when closed, thanks to the close contact between the disc and the seat. This minimizes leaks and ensures effective isolation.
Bi-Directional: While typically used in one direction, globe valves can be designed for bi-directional flow, adding to their versatility in system design.
Availability in Various Designs: Globe valves come in several body designs (Z-body, Y-body, and angle body), each offering specific advantages for different applications, such as minimized pressure drop or enhanced flow control.
Ease of Maintenance: Many globe valve designs allow for easy access to internal components, facilitating maintenance, repairs, and part replacements without removing the valve from the pipeline.

Disadvantages Of Globe Valves

Pressure Drop: The biggest drawback of globe valves is the inherent pressure drop across the valve, even when fully open. The flow path through the valve body is not straight, causing changes in flow direction and resistance that result in pressure loss.
Size and Weight: Globe valves tend to be larger and heavier than other valve types (like ball valves) of the same nominal size and pressure class, potentially requiring more space and support in a piping system.
Higher Operating Torque: Due to the design and the need for a tight seal, globe valves may require a higher torque to operate, especially in higher-pressure applications. This can necessitate larger or more powerful actuators.
Cost Considerations: Globe valves can be more expensive than other valve types, particularly in larger sizes, due to their complex design and the materials required for manufacturing.
Not Ideal for Slurry Applications: The tortuous flow path in a globe valve can lead to the accumulation of solids or slurries, which can affect the valve’s operation and lead to wear or damage.

In conclusion, globe valves are highly effective for applications requiring precise flow control and where the benefits of their design outweigh the potential drawbacks, such as in throttling applications and systems where a high degree of flow regulation is needed. However, for applications where pressure drop is a concern or where a straight-through flow path is required, alternative valve types may be more suitable.

MAIN PARTS OF GLOBE VALVES

A globe valve, widely used for regulating fluid flow in piping systems, consists of several key components that enable its operation and functionality. These main parts include:

1. Body

The body of the globe valve serves as the main structure that houses the internal components. It’s typically spherical or globular in shape, which is where the valve gets its name. The body material varies depending on the application and can include cast iron, stainless steel, brass, and other alloys suitable for specific fluid services.

2. Bonnet

The bonnet is attached to the valve body and provides a leak-proof closure at the top. It encases the stem and other internal parts, protecting them from external elements and containing the fluid pressure. The bonnet can be bolted, screwed, or welded to the valve body.

3. Seat

The seat is a critical component that provides a sealing surface for the disc to rest against when the valve is closed. It’s either integrated into the valve body or designed as a replaceable component. The seat material is selected based on the fluid type, temperature, and pressure, aiming for durability and a tight seal.

4. Disc

The disc, or plug, is the component that moves perpendicular to the flow path to regulate or block fluid flow. In globe valves, the disc can be a solid plug, a ring, or other shapes designed for specific flow characteristics. The disc’s precise positioning against the seat allows for effective flow control.

5. Stem

The stem connects the actuator (such as a handwheel or an electric actuator) to the disc. As the actuator is operated, the stem transmits the motion to the disc, moving it towards or away from the seat to open or close the valve. Stems can be rising (moving up and down with the disc) or non-rising, depending on the valve design.

6. Actuator

The actuator operates the valve, typically through a handwheel, lever, gear mechanism, or an automated actuator (electric, pneumatic, or hydraulic). Manual actuators like handwheels or levers are common for smaller valves or in applications where automatic control is not required.

7. Packing

Packing material is used to create a tight seal around the stem, preventing fluid leakage out of the valve body. It’s usually made from flexible materials like PTFE (Teflon), graphite, or other composites that can withstand the fluid’s temperature and chemical properties.

8. Gland And Gland Flange

The gland and gland flange assembly compresses the packing around the stem to ensure a tight seal. The gland flange allows for adjustments to the packing tightness, ensuring the seal’s effectiveness over time.

Each of these components plays a vital role in the globe valve’s operation, contributing to its ability to precisely control fluid flow, withstand varying pressure and temperature conditions, and maintain a reliable seal in diverse applications.

The image depicts the operation of a globe valve and its primary components: essentially, the flow is controlled by a disc that can be raised (either manually or with actuators) away from the seat, thereby adjusting the amount of flow permitted.

Fluid flow through a globe valve, pressure drop

KEY APPLICABLE SPECIFICATIONS (BS, API, ASME)

Globe valves, widely used for flow regulation in piping systems, are subject to various standards and specifications to ensure their reliability, safety, and compatibility across different applications. These standards are set by prominent organizations such as the British Standards Institution (BS), the American Society of Mechanical Engineers (ASME), and the American Petroleum Institute (API). Below is an overview of key BS, ASME, and API specifications applicable to globe valves:

BS (British Standards)

BS 1873: Specifies requirements for steel globe and globe stop and check valves for the petroleum, petrochemical, and allied industries. It covers valve design, materials, pressure-temperature ratings, and testing.
BS 5160: This standard is focused on steel globe valves, globe stop and check valves, check valves, and gate valves for general-purpose applications. It includes details on design, dimensions, testing, and marking.

ASME (American Society Of Mechanical Engineers)

ASME B16.34 – Valves – Flanged, Threaded, and Welding End: This standard provides requirements for materials, design, pressure-temperature ratings, and testing for gate, globe, check, ball, and butterfly valves. It is widely referenced for valve specifications in various industries.
ASME B16.10 – Face-to-Face and End-to-End Dimensions of Valves: While not specific to globe valves alone, this standard is crucial for determining the proper installation dimensions for globe valves, ensuring they fit correctly within piping systems.
ASME B16.5 – Pipe Flanges and Flanged Fittings: Relevant for globe valves with flanged connections, this standard specifies dimensions, tolerances, and materials for flanges and flanged fittings, ensuring compatibility with flanged piping systems.

API (American Petroleum Institute)

API 602 – Compact Steel Gate Valves – Flanged, Threaded, Welding, and Extended-Body Ends: Although primarily focused on gate valves, API 602 also covers small-sized, forged carbon steel globe valves used in the petroleum and natural gas industries.
API 598 – Valve Inspection and Testing: This standard outlines the testing and inspection requirements for gate, globe, and check valves, ensuring they meet the required leakage rates and performance criteria.
API 600 – Steel Gate Valves – Flanged and Butt-Welding Ends, Bolted Bonnets: Similar to API 602, API 600, while focused on gate valves, sets the benchmark for quality and performance applicable to globe valves, particularly in terms of design and material specifications for use in the petroleum and natural gas industry.

These BS, ASME, and API specifications cover a wide range of aspects related to globe valves, from design and manufacturing to testing and inspection. Compliance with these standards ensures that globe valves are suitable for their intended applications, offering reliable performance and safety in various industrial environments.

GLOBE VALVE TYPES

Globe valves, recognized for their ability to regulate flow in piping systems, come in various designs tailored to specific applications and flow characteristics. The primary differentiation among globe valve types lies in their internal body design, which impacts flow direction, pressure drop, and application suitability. Here’s a detailed look at the different types of globe valves:

1. Z-Body Globe Valve

The Z-body is the most common and traditional type of globe valve. It features a Z-shaped partition inside the valve body that directs the flow in a Z pattern. The seat and stem are positioned at an angle, typically at 90 degrees to the valve’s pipeline, which allows for a straightforward and effective method to start, stop, and regulate the flow.

Advantages: Simple design, easy to maintain.
Disadvantages: Higher pressure drop due to the flow path; not ideal for applications requiring minimal flow resistance.

2. Y-Body Globe Valve (“Wye” Type)

Y-body globe valves are designed to reduce the pressure drop across the valve. The stem and seat are angled at approximately 45 degrees to the pipe axis, which offers a smoother flow path for the fluid. This design is particularly beneficial for high-pressure and high-temperature applications, such as steam services.

Advantages: Lower pressure drop compared to Z-body valves, suitable for high-pressure conditions.
Disadvantages: The angled design may complicate installation in some piping configurations.

3. Angle Globe Valve

Angle globe valves have a 90-degree body design that changes the flow direction only once, which helps in reducing the pressure drop. These valves combine the functions of a globe valve and an elbow, making them suitable for applications where space constraints exist or where the piping system requires a directional change.

Advantages: Efficient flow with reduced pressure drop; can replace both a valve and an elbow in a system.
Disadvantages: Limited to applications where the change in flow direction is beneficial or required.

4. T-Pattern Or Through-Way Globe Valve

The T-pattern globe valve, also known as a through-way globe valve, offers a straighter flow path compared to the Z-body design, resulting in a somewhat lower pressure drop. It’s a variation more akin to traditional globe valves but optimized for better flow dynamics.

Advantages: Improved flow performance over Z-body designs; good for throttling and regulating.
Disadvantages: Still presents a higher pressure drop than ball or gate valves.

5. Oblique Pattern Globe Valve

Oblique pattern globe valves feature a body design where the inlet and outlet ports are oriented diagonally to each other, providing a more direct flow path than traditional Z-body designs. This type is less common but can be used in specific applications requiring efficient flow regulation with a moderate pressure drop.

Advantages: Moderately lower pressure drop compared to Z-body valves; effective for flow regulation.
Disadvantages: Not as widely available or standardized as other globe valve designs.

Each globe valve type offers distinct advantages for flow control and regulation, with the choice depending on specific application needs, performance requirements, and system design considerations.

The globe valve symbol in P&ID diagrams is the following:

GLOBE VALVE MATERIALS (CAST/FORGED)

Globe valves, utilized extensively for flow regulation in piping systems, can be constructed with either cast or forged body materials. The choice between cast and forged bodies depends on the application’s specific requirements, including pressure, temperature, and the fluid’s nature. Understanding the distinctions between cast and forged materials is crucial for selecting the appropriate globe valve for a particular service environment.

Cast Body Materials

Manufacturing Process: Casting involves pouring molten metal into a mold of the desired shape and allowing it to solidify. This process enables the production of complex shapes and sizes, making it suitable for manufacturing globe valve bodies with intricate internal geometries.

Materials: Common cast materials for globe valves include:

Cast Carbon Steel (e.g., ASTM A216 WCB): Widely used for moderate temperatures and pressures.
Cast Stainless Steel (e.g., ASTM A351 CF8M): Offers excellent corrosion resistance, suitable for aggressive media.
Cast Alloy Steel (e.g., ASTM A217 WC6): Used for high-temperature and high-pressure applications, resistant to thermal fatigue.

Advantages:

Versatility in design and size.
Generally more cost-effective for large sizes due to simpler manufacturing for complex shapes.
Suitable for lower pressure-temperature applications.

Disadvantages:

Potential for casting defects (e.g., porosity, inclusions), which could affect the valve’s integrity and performance.
Material properties may be less uniform compared to forged valves.

Forged Body Materials

Manufacturing Process: Forging involves shaping metal under high pressure, typically by hammering or pressing. This process aligns the metal’s grain structure, enhancing its strength and durability.

Materials: Common forged materials for globe valves include:

Forged Carbon Steel (e.g., ASTM A105): Offers good strength and impact resistance, suitable for general service applications.
Forged Stainless Steel (e.g., ASTM A182 F316): Provides superior corrosion resistance, ideal for corrosive environments.
Forged Alloy Steel (e.g., ASTM A182 F11): Used in high-temperature services, offering excellent mechanical properties.

Advantages:

Higher strength and toughness due to the forging process, make them suitable for high-pressure and high-temperature applications.
Reduces the likelihood of material defects, ensuring greater reliability and performance.
More uniform material properties, providing consistent performance.

Disadvantages:

The range of shapes and sizes is more limited compared to casting, potentially increasing the cost of complex designs.
Generally more expensive than cast valves, especially for larger sizes, due to the intensive labor and material requirements of the forging process.

Choosing Between Cast And Forged Globe Valves

When selecting between cast and forged globe valves, consider the following factors:

Service Conditions: Forged valves are preferred for severe service conditions involving high pressure and temperature, where material strength and integrity are critical.
Fluid Properties: Cast valves may be more suitable for applications involving corrosive media, given the availability of various corrosion-resistant alloys.
Cost Considerations: For large valves or when cost is a significant factor, cast valves might offer a more economical solution.
Design Complexity: Complex valve designs with intricate internal features are more easily achieved with casting.

Ultimately, the choice between cast and forged globe valves depends on balancing the application’s specific demands with considerations of performance, reliability, and cost.

GLOBE VALVE VS. OTHER TYPES OF VALVE

GLOBE VALVE VS GATE VALVE

Globe valves and gate valves are two widely used valve types in piping systems, each serving distinct functions with specific advantages and applications. Understanding the differences between these two valve types is crucial for selecting the right valve for a particular system requirement.

Design And Operation

Globe Valves: Designed for regulating flow, globe valves feature a movable disk or plug that comes into contact with a stationary ring seat to control flow. The flow path through a globe valve typically changes direction, which provides the valve with good throttling capabilities and the ability to precisely control the flow rate. The movement of the disk is perpendicular to the seat, allowing for fine adjustments of flow.
Gate Valves: Primarily used for on/off control, gate valves have a gate or wedge that moves up and down in the flow path. When the gate valve is fully open, it provides a straight-through passage with minimal obstruction to flow, resulting in a very low-pressure drop. Gate valves are not suitable for throttling purposes because partial opening can cause vibration and rapid wear of the gate and seats.

Applications

Globe Valves: Because of their excellent ability to regulate flow, globe valves are often used in applications where flow needs to be adjusted regularly or where flow rate must be precisely controlled, such as in cooling systems, fuel oil systems, and process control in chemical plants.
Gate Valves: Gate valves are best suited for applications where a valve primarily needs to be either fully open or fully closed and where minimal pressure drop is desired. They are commonly used in water and wastewater treatment, oil and gas pipelines, and other applications where fluid needs to flow freely without obstructions.

Advantages And Disadvantages

Globe Valves:
- Advantages: Excellent for throttling and regulating flow; provide a good seal when closed.
- Disadvantages: The flow path through the valve causes a higher pressure drop compared to gate valves; generally, more expensive due to their complex design.
Gate Valves:
- Advantages: Low-pressure drop when fully open; simpler design usually results in lower costs; suitable for both cryogenic and high-temperature applications.
- Disadvantages: Not suitable for throttling; prone to seat and gate damage if operated partially open; slower to open and close due to the need to move the gate out of the flow path.

Choosing Between Globe And Gate Valves

When choosing between a globe valve and a gate valve, consider:

Purpose: If precise flow control or throttling is needed, a globe valve is preferable. For simple on/off control with minimal pressure drop, a gate valve is more suitable.
Operating Conditions: Consider the system’s pressure, temperature, and the nature of the fluid.
Cost and Space: Globe valves typically require more space and are more expensive than gate valves due to their design complexity.

In summary, the choice between globe and gate valves depends on the specific needs of the application, including whether flow needs to be precisely controlled or if the primary requirement is the minimal restriction of flow.

GLOBE VALVE VS BALL VALVE

Globe valves and ball valves are two distinct types of control valves used across various industries for fluid management in piping systems. Each valve type offers unique features and operational benefits, making them suitable for specific applications based on the requirements of flow control, pressure drop, and sealing efficiency. Understanding the differences between these valves is crucial for making an informed selection that aligns with system requirements.

Design And Operation

Globe Valves: Globe valves are characterized by their spherical body shape with a baffle that splits the interior space into two chambers. They regulate flow through a movable disk (or plug) and a stationary ring seat. The disk moves perpendicularly to the seat, offering precise control over the flow rate by adjusting the gap between the disk and the seat. Globe valves are primarily designed for throttling and regulating flow.
Ball Valves: Ball valves feature a spherical ball with a hole (or bore) through its center. Rotating the ball 90 degrees around its axis opens or closes the flow path. In the open position, the hole in the ball aligns with the flow path, allowing fluid to pass through with minimal resistance. Ball valves are known for their on/off control but can also provide throttling capabilities when equipped with a control mechanism.

Applications

Globe Valves: Due to their excellent capability to regulate flow, globe valves are commonly used in applications requiring precise flow control, such as in HVAC systems, chemical processing plants, and water distribution networks. They are especially useful where flow needs to be adjusted or maintained at a specific rate.
Ball Valves: Ball valves are versatile and suitable for a wide range of applications, from residential water systems to industrial processes involving gases and liquids. They are preferred for applications requiring a tight seal and quick, reliable on/off operation, such as in gas pipelines and storage tanks. Some specialized ball valves are designed for flow modulation in process control.

Advantages And Disadvantages

Globe Valves:
- Advantages: Excellent for precise flow control and regulation; capable of withstanding high pressure; good sealing capabilities.
- Disadvantages: Higher pressure drop due to the tortuous flow path; generally larger and more expensive than ball valves; slower to operate.
Ball Valves:
- Advantages: Low-pressure drop when fully open; quick and easy to operate with a quarter-turn mechanism; provides a tight seal with low torque.
- Disadvantages: Not as precise for flow control as globe valves; can be prone to cavitation and erosion in throttling applications; limited suitability for slurry applications due to potential clogging.

Choosing Between Globe And Ball Valves

When choosing between a globe valve and a ball valve, consider the following:

Flow Control Requirements: For precise flow regulation, a globe valve is preferable. For on/off control or applications requiring minimal pressure drop, a ball valve is more suitable.
Operating Conditions: Consider the fluid properties, pressure, temperature, and whether the system requires frequent operation.
Cost and Space Constraints: Ball valves are typically more compact and cost-effective than globe valves, making them attractive for space-constrained or budget-sensitive applications.

In summary, the choice between globe and ball valves hinges on the specific needs of the application, with globe valves being the go-to option for precise flow control and ball valves offering superior performance for on/off control and applications requiring minimal pressure drop.

GLOBE VALVE VS BUTTERFLY VALVE

Globe valves and butterfly valves serve different purposes in fluid control systems, each with distinct design features, operational advantages, and preferred applications. Understanding the differences between these two types of valves can help in selecting the most suitable valve for a specific application based on the requirements of flow control, pressure drop, sealing efficiency, and cost.

Design And Operation

Globe Valves: Globe valves are characterized by a spherical body with an internal baffle that divides the interior into two chambers. They control fluid flow using a movable disk (or plug) and a stationary ring seat. The disk moves linearly, perpendicular to the flow, allowing for precise flow regulation by adjusting the gap between the disk and the seat. Globe valves are designed primarily for throttling and fine flow control.
Butterfly Valves: Butterfly valves consist of a flat disc that rotates around a central axis within the valve body. Turning the disc 90 degrees opens or closes the valve. When the disc is parallel to the flow, the valve is fully open, and when it is perpendicular, the valve is closed. Butterfly valves are known for their compact design and are used for both on/off control and moderate flow regulation.

Applications

Globe Valves: Ideal for applications requiring precise flow control and where pressure drop is not a significant concern. They are commonly used in water treatment plants, fuel oil systems, and chemical processing industries where the accurate adjustment of flow rate is necessary.
Butterfly Valves: Suitable for a wide range of applications, butterfly valves are often used in large-diameter pipes for water distribution, HVAC systems, and in applications where space and weight are critical considerations. They provide efficient on/off and throttling control with minimal structural support.

Advantages And Disadvantages

Globe Valves:
- Advantages: Excellent for precise flow regulation; good sealing capabilities; suitable for high-pressure applications.
- Disadvantages: Higher pressure drop across the valve due to the tortuous flow path; larger and more expensive compared to butterfly valves; slower to actuate.
Butterfly Valves:
- Advantages: Compact and lightweight design; quick operation with a quarter-turn mechanism; lower cost, especially for large-diameter applications; lower pressure drop when fully open.
- Disadvantages: Not as precise in flow control as globe valves; potential for reduced sealing effectiveness over time, especially in high-pressure applications; can be susceptible to cavitation and flow turbulence.

Choosing Between Globe And Butterfly Valves

When choosing between a globe valve and a butterfly valve, consider the following factors:

Flow Control Requirements: Globe valves are better for situations that require precise flow control. Butterfly valves are more suitable for general on/off and moderate flow regulation applications.
Space and Weight: Butterfly valves are preferred when space is limited and weight is a concern.
Pressure Drop: If minimizing pressure drop is essential, butterfly valves offer an advantage due to their straight-through flow design.
Budget Constraints: Butterfly valves are generally more cost-effective, especially for large pipe diameters.

In summary, the choice between globe and butterfly valves depends on the specific application requirements. Globe valves are ideal for precise flow control in high-pressure systems, while butterfly valves offer a compact, economical solution for on/off and moderate flow regulation in larger pipes and where space constraints exist.

GLOBE VALVE VS PLUG VALVE

Globe valves and plug valves are both commonly used in various industries for controlling fluid flow in piping systems. Each type of valve has distinct features, operational mechanisms, and advantages that make it suitable for specific applications. Understanding these differences is crucial for selecting the right valve for your needs.

Globe Valves

Design and Operation:

Globe valves are characterized by their spherical body shape, with an internal baffle that splits the interior into two chambers.
They control flow using a movable disk (or plug) and a stationary ring seat. The disk moves linearly, perpendicular to the flow direction, allowing for precise flow regulation by adjusting the gap between the disk and the seat.
Primarily designed for throttling and regulating flow, globe valves offer excellent control over flow rate.

Applications:

Ideal for applications requiring precise flow control, such as cooling systems, fuel oil systems, and chemical processing.
Commonly used in situations where the flow needs to be adjusted frequently or maintained at a specific rate.

Advantages:

Excellent for precise flow regulation and control.
Provides a good sealing capability when closed.
Suitable for both high-pressure and high-temperature applications.

Disadvantages:

Higher pressure drop due to the tortuous flow path.
Larger and more expensive compared to other valve types.
Not suitable for applications requiring minimal flow resistance or for handling slurries and viscous fluids.

Plug Valves

Design and Operation:

Plug valves feature a cylindrical or tapered plug with a hole or passage that allows fluid to flow through when aligned with the inlet and outlet ports.
The plug rotates within the valve body to open or close the flow path. This rotation aligns the port in the plug with the valve body ports.
Plug valves can be used for on/off control as well as for moderate throttling applications.

Applications:

Widely used in applications requiring quick and easy operation, such as in water and wastewater treatment, gas services, and in industries where fast isolation is needed.
Suitable for handling fluids with suspended solids, due to the straight-through flow path.

Advantages:

Simple and compact design, making them easy to operate and maintain.
Quick to open and close, providing efficient flow control.
Generally more resistant to clogging from slurries or viscous fluids compared to globe valves.

Disadvantages:

Not as precise in flow control as globe valves.
The sealing surfaces can wear out more quickly, potentially leading to leaks.
Some designs may have higher torque requirements and can be more difficult to operate under high-pressure conditions.

Choosing Between Globe And Plug Valves

When choosing between a globe valve and a plug valve, consider the following:

Flow Control Needs: Globe valves are preferred for precise flow regulation, while plug valves are better for quick isolation and applications requiring frequent operation.
Fluid Characteristics: Plug valves are more suitable for fluids with suspended solids, whereas globe valves are ideal for clean liquids or gases.
Pressure Drop: If minimizing pressure drop is a priority, plug valves may offer an advantage due to their straight-through flow design.
Application Requirements: Consider the specific requirements of your application, including temperature, pressure, and the need for flow adjustment or quick isolation.

In summary, the choice between globe and plug valves depends on the specific needs of the application, including the level of flow control required, the type of fluid being handled, and operational considerations.

GLOBE VALVE GA DIAGRAM

Note: GA stands for “General Assembly” (drawing).

A general assembly drawing for globe valves is shown in the image:

Nonetheless, a large number of variations exist, depending on the following factors:

body material: cast (BS 1873) and forged (API 602/BS 5352)
bonnet design: standard or pressure seal type (for high-pressure applications)
bonnet to body connection: bolted or welded
valve end connections type: flanged (as shown in the image), buttweld, socket weld/threaded (forged bodies)
disc type
stem type (rising/non-rising)
seal type: conical or flat
specification: BS, API, EN
type of actuation: manual, with a gearbox, with an actuator

GLOBE VALVES DIMENSIONS

The tables show the dimensions and weights of BS 1873 valves, bolted bonnet type.
Globe valves dimensions

CLASS 150

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	8 (203)	13-3/8 (340)	8-7/8 (225)
2-1/2″	8-1/2 (216)	14-1/2 (368)	8-7/8 (225)
3″	9-1/2 (241)	16-1/2 (419)	11-7/8 (302)
4″	11-1/2 (292)	17-3/8 (441)	12-3/4 (325)
5″	14 (356)	24 (610)	12-3/4 (325)
6″	16 (406)	24 (610)	17-3/4 (451)
8″	19-1/2 (495)	26-3/4 (679)	21-5/8 (549)
10″	24-1/2 (622)	30 (762)	30 (762)
12″	27-1/2 (699)	33-7/8 (860)	30 (762)
14″	31 (787)	56 (1422)	31-1/2 (800)
16″	36 (914)	64 (1626)	35-1/2 (902)
GEAR OPERATOR RECOMMENDED FOR SIZE 10″ AND ABOVE

CLASS 300

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	10-1/2 (267)	13-3/8 (340)	9 (229)
2-1/2″	11-1/2 (292)	15-3/8 (390)	9 (229)
3″	12-1/2 (318)	16-1/2 (419)	13 (330)
4″	14 (356)	19-3/8 (492)	14 (356)
5″	15-3/4 (400)	21-1/2 (546)	15-3/4 (400)
6″	17-1/2 (445)	24-3/8 (619)	17-3/4 (451)
8″	22 (559)	31-1/4 (794)	22 (559)
10″	24-1/2 (622)	45 (1143)	34 (864)
12″	28 (711)	49 (1245)	34 (864)
GEAR OPERATOR RECOMMENDED FOR SIZE 8″ AND ABOVE

CLASS 600

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	11-1/2 (292)	15-1/2 (394)	9-1/2 (241)
2-1/2″	13 (330)	17 (432)	11 (279)
3″	14 (356)	19 (483)	13 (330)
4″	17 (432)	21 (533)	14 (356)
5″	20 (508)	25 (635)	15-3/4 (400)
6″	22 (559)	26-7/8 (683)	18 (457)
8″	26 (660)	35 (889)	20 (508)
10″	31 (787)	49 (1245)	24 (610)
12″	33 (838)	58 (1473)	30 (762)
GEAR OPERATOR RECOMMENDED FOR SIZE 8″ AND ABOVE

CLASS 900

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	14-1/2 (368)	20-1/2 (521)	12 (305)
3″	15 (381)	22-3/4 (578)	14 (356)
4″	18 (457)	26-1/2 (673)	21-1/2 (546)
6″	24 (610)	36 (914)	20 (508)
8″	29 (737)	37 (940)	24 (610)
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

CLASS 1500

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	14-1/2 (368)	24 (610)	14 (356)
3″	18-1/2 (470)	26 (660)	16 (406)
4″	21-1/2 (546)	28 (711)	18 (457)
6″	27-3/4 (705)	37-1/2 (952)	24 (610)
8″	32-3/4 (832)	45 (1143)	24 (610)
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

CLASS 2500

Dimensions in inches (millimeters)

Sizes	L / L1	H (Open)	W
2″	17-3/4 (451)	25-1/2 (648)	16 (406)
3″	22-3/4 (578)	32-1/2 (825)	20 (508)
4″	26-1/2 (673)	47 (1194)	24 (610)
6″	36 (914)	70-1/2 (1790)	28 (711)
8″	40-1/4 (1022)	/	/
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

May 23, 2024/by stvvalve

industry valve news, News

Understand Mill Test Certificates EN 10204 2.1, 3.1, 3.2 and their Differences

A Mill Test Certificate (MTC), or Mill Test Report (MTR), is issued by a manufacturer to certify the chemical and mechanical features of a product and its compliance with the applicable norms and technical specifications. Typically, Mill Test Certificates conform to the EN 10204 standard and are related to steel products. Mill Test Certificates (when required and/or applicable) shall be submitted by the exporter to the importer at shipping, together with the other typical shipping documents (invoices, packing lists, transportation docs)

MILL TEST CERTIFICATE

DEFINITION OF MTC

A Mill Test Certificate (MTC), otherwise defined as a “Mill Test Report” (MTR), is a certified document provided by a manufacturer that attests to the chemical and physical properties of a material or a product (for example a pipe, or a pipe fitting).

These certificates are often required in the metals industry to verify that the material meets the specified criteria and standards for a particular application. For products obtained by assembling or processing other components and/or parts (for example a 90 degrees elbow which is manufactured by cutting, bending, and forming a “mother” pipe), the manufacturer shall deliver both the mill test certificate of the end product (the elbow itself, in this example, if applicable), and of the mother-product (the pipe/s in this case).

MTCs are crucial in industries where materials’ quality and composition are critical for safety and performance, such as construction, manufacturing, and energy sectors (including petrochemicals and oil and gas).

WHY MILL TEST CERTIFICATES ARE IMPORTANT

When purchasing metal products, or products made of metals like pipes, valves, fittings, and flanges, buyers shall always request a mill test certificate from the manufacturer or distributor. This is critical for several reasons:

Quality Assurance: MTCs provide assurance that the materials supplied meet the required standards and specifications, offering a traceable record of the material’s origin and properties.
Compliance: For projects that must adhere to specific engineering standards and codes, MTCs are vital for ensuring compliance with these regulations.
Safety: In critical applications where material failure can lead to severe consequences, MTCs help ensure that only materials with the appropriate quality and strength are used.
Risk Management: Having an MTC reduces the risk of using substandard materials in projects, which can lead to costly repairs, replacements, and even accidents.

TYPE OF INFORMATION SHOWN ON MTC’s

A mill test certificate to EN 10204 shows, generally, the following information:

The Manufacturer’s name and address (with any other business info related to the manufacturing plant)
The indication/text “Mill Test Certificate” or “Mill Test Report” at the top of the document
The date of the MTC
The Type of MTC (for example “EN 10204 3.1” or “EN 10204 3.2” – see below)
The page number and the total number of pages of the MTC (for example “2/12” – i.e. page 2 of 12)
The customer name (that could be the end-user or a distributor/trader)
The exact definition of the material/product covered by the MTC
- Product name and type (for example “Seamless Pipes”)
- The manufacturing process (for example “Seamless hot rolled”)
- The surface type (for example “Varnished”)
- The dimensions of the product (for example NPS x WT, plus lengths)
The quantity covered by the specific MTC in units (for example “meters 100”), the nominal weight in kgs/lbs (for example 2.600 kgs/tons), the net/gross weight (if available)
The final test result for the different physical attributes of the material by heat number (for example results of the tensile strength, hardness, sulfide stress cracking, and chemical composition…by heat number) concerning allowed tolerances (set by the applicable specifications and/or standards)
Results of additional tests, like hydrostatic, ultrasounds (UT), hardness, impact test, magnetic particles, metal graphic result, etc.
Marking information and details applied to the material/batch covered by the MTC
Summary information
Addenda useful to appraise the full features of the product
Stamps & Signatures of the Manufacturer’s Quality Dept. representatives that executed the tests
Customer signature
Stamps & Signatures of the Third-Party Inspector (if applicable, for example in EN 10204 3.2)

MAIN TYPES OF MTC (2.1, 2.2, 3.1, 3.2)

There are typically four types of Mill Test Certificates (from the lightest in terms of independent inspection, i.e. 2.1, to the toughest, i.e. 3.2):

EN 10204 Type 2.1

EN 10204 Type 2.1 is a type of certification provided by manufacturers of metallic products, such as plates, bars, tubes, and forgings. According to the EN 10204 standard, which outlines different types of inspection documents for metallic products, a Type 2.1 certificate is a declaration of compliance with the order by the manufacturer. Unlike Type 3.1 or Type 3.2 certificates, Type 2.1 does not involve independent third-party verification.

Key Features Of EN 10204 Type 2.1 Certificate

Declaration of Compliance: The Type 2.1 certificate is essentially a statement from the manufacturer affirming that the supplied products comply with the requirements of the order. This includes adherence to specified dimensions, material grade, and general quality parameters.
Content: The certificate typically includes the manufacturer’s details, product description, order details, and a statement of compliance. However, it does not include detailed test results or specific property values of the material (such as chemical composition or mechanical properties).
Verification: There is no requirement for the manufacturer to present actual test results or for a third-party inspection agency to verify the product. The assurance provided is based solely on the manufacturer’s internal quality control processes.

Applications And Considerations

General Use: Type 2.1 certificates are generally suitable for applications where the detailed material properties are not critical to the application’s safety or performance, or where the buyer has other means of verifying material quality.
Limitations: For projects requiring stringent adherence to specific material properties or standards, a Type 2.1 certificate may not provide sufficient assurance. In such cases, Type 3.1 or Type 3.2 certificates, which include detailed material properties and, for Type 3.2, third-party verification, are preferable.
Selection Criteria: When choosing materials or specifying certificate types, it’s important to consider the application’s requirements, potential risks, and regulatory obligations. Type 2.1 certificates may be acceptable for less critical applications, but more demanding environments would benefit from the higher assurance levels provided by Type 3.1 or Type 3.2 certificates.

In summary, an EN 10204 Type 2.1 certificate provides a basic level of assurance, confirming that the product complies with the order specifications without including specific test results. It is up to the buyer to determine if this level of certification is adequate for their application, considering the material’s intended use and the potential consequences of material failure.

EN 10204 Type 2.2

EN 10204 Type 2.2 is a certification standard outlined in the EN 10204 specification, which defines different types of inspection documents provided by manufacturers concerning the delivery of metallic products such as plates, bars, forgings, and castings. Type 2.2 certification provides a declaration of compliance with the order, by the manufacturer.

Key Features Of EN 10204 Type 2.2 Certificate

Compliance Declaration: It declares that the products supplied are in compliance with the order requirements, but unlike Type 3.1 or 3.2 certificates, it does not include specific test results.
Testing and Inspection Data: While specific test results are not included, the certificate generally states that the products have been tested by the standard and specific norms applicable to the products. It summarizes the inspection and testing performed and confirms that the products meet the definitions and guidelines of the standard.
Manufacturer’s Confirmation: The certificate is issued by the manufacturer and must be authorized by the manufacturer’s personnel. However, it does not require independent verification by an external inspector (as is necessary for Type 3.2 certification).

Application And Use

EN 10204 Type 2.2 certificates are used in situations where the buyer requires more information than what is provided in a Type 2.1 declaration of compliance without inspection documents. It assures buyers that the products meet the order requirements based on non-specific inspections and tests conducted by the manufacturer. However, for applications requiring detailed material properties and third-party verification, Type 3.1 or 3.2 certificates might be necessary.

Type 2.2 certificates are suitable for applications where the risk is relatively low, and the cost or necessity of a more detailed certification (like Type 3.1 or 3.2) cannot be justified. They are often used in general engineering applications where the precise material properties are not critical to the application’s performance or safety requirements.

EN 10204 Type 3.1

EN 10204 Type 3.1 is a certification standard outlined within the EN 10204 specification, which dictates the different types of inspection documents supplied by manufacturers with the delivery of metallic products, such as plates, bars, forgings, and castings. Type 3.1 certification provides specific information about the material’s properties and its compliance with the order requirements, including details on chemical composition, mechanical properties, and any additional testing that was performed.

Key Features Of EN 10204 Type 3.1 Certificate

Test Results: The certificate includes actual test results for the specific items supplied. This may cover chemical composition, mechanical properties (such as tensile strength, yield strength, elongation, and impact resistance), and other tested attributes relevant to the order specifications.
Validation: The Type 3.1 certificate must be validated by the manufacturer’s authorized inspection representative who is independent of the manufacturing department. This provides a level of assurance that the products meet the specified requirements.
Traceability: It offers traceability of the material by including details like heat or batch number, which connects the product with the test results documented in the certificate.
Compliance: It declares that the products supplied follow the requirements of the order, based on specific inspections and tests.

Application And Use

EN 10204 Type 3.1 certificates are widely required in industries where material properties are critical for the application’s safety and functionality. This includes the oil and gas, chemical processing, power generation, and construction sectors, among others. Type 3.1 certification is often specified in contracts and procurement documents to ensure that the materials supplied can be verified to have met the required standards and specifications.

The inclusion of specific test results provides buyers and engineers with confidence in the material’s suitability for the intended application, particularly in critical and high-performance environments. For applications requiring even higher assurance, including third-party verification, an EN 10204 Type 3.2 certificate might be requested.

In summary, an EN 10204 Type 3.1 certificate is a vital document that ensures the reliability and quality of materials used in various sectors, serving as an important element of quality assurance programs and compliance with regulatory standards.

EN 1024 3.1 MILL TEST CERTIFICATE TYPES A/B/C

Certificate type	Title	Summary of EN10204 requirements	Notes
3.1	Inspection certificate	Statement of compliance with the order by the manufacturer with results of specific inspection	Replaces 3.1B. Common certificate type issued for ‘batch tested’ material. Cert. issued and signed by the manufacturer’s representative, who must be independent of the manufacturing department. Eg Inspection department or test house manager/supervisor.
3.1A	Inspection certificate 3.1A	With a mention of test results from specific inspections and testing	Batch test results. Cert. issued by independent inspector required by releasing authority (eg TUV for German pressure vessels). Replaced by 3.2 in 2004
3.1B	Inspection certificate 3.1B	With a mention of test results from specific inspections and testing	Batch test results. Cert. issued and signed by the manufacturer’s representative. Replaced by 3.1 in 2004
3.1C	Inspection certificate 3.1C	With a mention of test results from specific inspections and testing	Batch test results. Cert. issued by an independent inspector appointed by a customer (eg Lloyds). Replaced by 3.2 in 2004

EN 10204 Type 3.2

EN 10204 Type 3.2 certification is a standard outlined within the EN 10204 specification, which defines the different types of inspection documents supplied by manufacturers with the delivery of metallic products. Type 3.2 certification is among the most stringent and provides assurance regarding the conformity of the products to the specified order requirements and applicable standards.

Key Features Of EN 10204 Type 3.2 Certificate

Third-Party Verification: The distinctive feature of Type 3.2 certification is that it involves independent verification by a third-party inspector. This third party is either an authorized representative of the purchaser, a designated inspection representative independent of the manufacturing department, or a representative from an officially recognized inspection agency.
Specific Test Results: Similar to Type 3.1, the Type 3.2 certificate includes specific test results for the product, such as chemical composition and mechanical properties. However, the presence of the third-party inspector’s validation adds an additional layer of assurance.
Traceability: Provides traceability of the material back to its production batch, correlating the product with specific test results and ensuring that the material meets the required specifications.
Documented Verification: Both the manufacturer and the independent third party must sign the Type 3.2 certificate, attesting to the conformity of the product with the order requirements.

Application And Use

EN 10204 Type 3.2 certificates are required in critical applications where the material’s integrity is paramount. These include sectors like aerospace, oil and gas, power generation, and naval construction, where failure could lead to catastrophic consequences. Type 3.2 certification is often specified for components that are subject to high stress, corrosive environments, or extreme temperatures.

The involvement of a third-party inspector provides added assurance to buyers and project managers that the materials and products have been thoroughly tested and inspected, not only by the manufacturer but also by an unbiased external entity. This level of scrutiny is crucial for projects with stringent safety and reliability standards.

Importance

Type 3.2 certification is vital for ensuring the highest levels of material compliance and quality in industries where failure is not an option. The dual verification process—by both the manufacturer and an independent third party—helps mitigate risks associated with material defects and non-conformities, ensuring that only materials that fully meet the specified requirements are used in critical applications.

In summary, EN 10204 Type 3.2 certification represents the highest standard of assurance provided in the EN 10204 specification, offering comprehensive validation of a material’s properties and compliance through independent third-party inspection.

Example of mill test certificate 3.1 (for a pipe)

Sample mill test certificate (Tenaris steel pipes).

SUMMARY TABLE FOR MTC’S

	Mill Test Certificate denomination in…
MTC Type EN 10204	English	German	French	Scope	MTC to be validated by…
MTC Type 2.1	Declaration of compliance with the order	Werk- Bescheinigung	Attestation de conformité á la Commande	Statement of compliance with the order	The manufacturer
MTC Type 2.2	Test report	Werkzeugnisse	Relvé de contrôle	Statement of compliance with the order by the manufacturer based on non-specific inspections (tests) by the manufacturer.	The manufacturer
MTC Type 3.1	Inspection certificate 3.1	Abnahmeprüf- Zeugnisse 3.1	Certificat de réception 3.1	Statement of compliance with the order by the manufacturer with results of a specific inspection	The manufacturer`s authorized inspection representative, independent by the manufacturing department
MTC Type 3.2	Inspection certificate 3.2	Abnahmeprüf- Zeugnisse 3.2	Certificat de réception 3.2	Statement of compliance with the order with an indication of results of a specific inspection	The manufacturer`s authorized inspection representative independent by the manufacturing department Either the purchaser`s authorized inspection representative or a third-party inspector

The main differences among the MTCs 2.1, 2.2, 3.1, and 3.2 are:

Level of Detail: Types 2.1 and 2.2 provide general declarations of compliance, with Type 2.2 offering a bit more detail on testing and inspection processes. Types 3.1 and 3.2 provide specific test results, with Type 3.2 including third-party verification.
Verification: Types 3.1 and 3.2 certificates are more rigorous, including specific test results and requiring validation by independent parties (Type 3.2 only).
Application Use: Types 3.1 and 3.2 are typically required in more critical applications, where specific material properties must be verified and documented for safety, performance, and compliance reasons.

FORGERY OF MILL TEST CERTIFICATES

Fake Mill Test Certificates (MTCs) pose a significant risk to industries that rely on certified materials for safety, performance, and compliance with standards.

These counterfeit documents are fabricated to appear as if they certify a material’s properties and compliance with specifications, but they do not accurately reflect the material’s actual characteristics. The existence of fake MTCs underscores the importance of due diligence and verification in the procurement process. Here are key points regarding fake Mill Test Certificates and how to mitigate their risks:

Risks And Consequences Of Fake MTCs

Compromised Safety: Using materials that do not meet required standards can lead to failures, posing severe safety risks to personnel and the environment.
Legal and Financial Liabilities: Organizations may face legal penalties, costly recalls, or project delays if substandard materials are discovered in their products or infrastructure.
Damaged Reputation: The use of non-compliant materials can tarnish a company’s reputation and erode trust among clients and partners.
Identifying And Preventing The Use Of Fake MTCs
1. Verify with the Manufacturer: Directly contact the material manufacturer to verify the authenticity of the MTC. Most reputable manufacturers can confirm the validity of their certificates.
2. Third-Party Verification: Utilize services from independent third-party inspection agencies to validate the material properties and the authenticity of the MTC. This is especially crucial for critical applications.
3. Check for Inconsistencies: Scrutinize the MTC for any inconsistencies or errors in formatting, spelling, or data that might indicate forgery. Compare the certificate’s format with known genuine examples from the same manufacturer.
4. Traceability: Ensure that the MTC includes clear traceability information, such as heat or batch numbers, and verify this information against the physical product.
5. Quality Assurance Processes: Implement robust quality assurance procedures for verifying and documenting the receipt and inspection of materials. This can include regular audits of suppliers and testing of material samples.
6. Supplier Audits: Conduct thorough audits of suppliers to assess their credibility, quality control practices, and the authenticity of their documentation.
7. Education and Training: Educate procurement and engineering teams about the risks of fake MTCs and train them on how to recognize and report suspected forgeries.
Industry Collaboration And Reporting

Encourage and participate in industry-wide efforts to combat the proliferation of fake MTCs. Reporting suspected fake certificates to relevant authorities and industry associations can help raise awareness and lead to the development of more effective prevention strategies.

By taking proactive steps to verify the authenticity of Mill Test Certificates, companies can significantly reduce the risks associated with the use of non-compliant materials, safeguarding their projects, reputation, and, most importantly, the safety of all stakeholders.

Blockchain Technology Could Help Fight Fake MTCs

Using Non-Fungible Tokens (NFTs) to prevent the counterfeiting of industrial products is an innovative application of blockchain technology. NFTs, which are unique digital certificates stored on a blockchain, provide a secure and tamper-proof method of verifying the authenticity, ownership, and provenance of both digital and physical goods.

blockchain

Here’s how NFTs can be used to combat counterfeiting in the industrial sector:

1. Digital Authentication:
- Creating NFTs for Physical Products: Each physical product or component can be paired with a unique NFT that serves as a digital twin. This NFT contains critical data about the product, including manufacturing details, batch numbers, and certification information.
- Secure Storage: Information within NFTs is stored on a blockchain, making it immutable and protected against unauthorized alterations. This ensures that the product’s digital certificate of authenticity cannot be forged.
2. Provenance Tracking
- Comprehensive History: NFTs can store the entire history of a product, from its production through its various ownership and transaction stages. This level of traceability is invaluable for verifying the product’s journey and ensuring it has not been tampered with or replaced by counterfeits.
- Supply Chain Transparency: Implementing NFTs throughout the supply chain enhances transparency, allowing buyers to verify the origin and journey of the products and components they purchase.
3. Ownership Verification
- Transferable Records: NFTs can facilitate the transfer of ownership records securely and efficiently. When a product is sold or changes hands, its corresponding NFT is transferred to the new owner, providing a clear and indisputable record of ownership.
- Access Control: Only authorized parties can access and update the NFT, ensuring that the product’s ownership and history are securely managed.
4. Integration With Smart Contracts
- Automated Verification: Smart contracts, self-executing contracts with the terms of the agreement directly written into code, can be used in conjunction with NFTs to automate verification processes, payments, and transfers of ownership, further securing transactions against fraud.
- Conditional Transactions: Smart contracts can enforce conditions that must be met for a transaction to occur, such as the verification of a product’s authenticity through its NFT before a sale can be completed.
5. Challenges And Considerations
- Physical-Digital Link: Ensuring a secure and tamper-proof link between the physical product and its digital NFT is crucial. This may involve secure tagging technologies, such as RFID chips, QR codes, or holograms, that can securely associate a physical item with its digital counterpart.
- Adoption and Standardization: Widespread adoption of NFTs for anti-counterfeiting measures requires collaboration and standardization across industries and supply chains. Establishing common standards and practices is essential for interoperability and effectiveness.
- Legal and Regulatory Compliance: The use of NFTs must comply with existing regulations and laws, including those related to data privacy, digital assets, and cross-border transactions.
By leveraging NFTs and blockchain technology, companies in the industrial sector can significantly enhance the security, transparency, and efficiency of their operations, providing a powerful tool against the challenges posed by counterfeit products.

May 23, 2024/by stvvalve

industry valve news, News

Valve Parts Body, Bonnet, Trim, Seats, and Packing

BODY

In the oil and gas industry, a valve body is the primary and critical component of a valve, functioning as the main structure that holds the valve together and contains the fluid flow. Made from materials capable of withstanding the harsh conditions and substances found in oil and gas applications, the valve body is engineered to handle high pressures, corrosive materials, and extreme temperatures. The body holds in position the moving components in contact with the fluid and has to withstand the pressure existing in the piping system.

Valve bodies in the oil and gas sector are typically constructed from robust materials such as carbon steel, stainless steel, alloy steels, and sometimes special alloys like Inconel, Monel, and Hastelloy. The choice of material depends on the specific application’s demands, including the type of fluid (oil, gas, water, etc.), temperature, pressure, and potential corrosive interactions. For instance, stainless steel and special alloys are preferred in environments where corrosion resistance is paramount.

The body can be manufactured by casting or forging steel in a variety of shapes, designs, and grades.

In the oil and gas industry, the most common materials for cast bodies are ASTM A216 and ASTM A105 for forged bodies (high-temperature service). For low-temperature service, ASTM A352 LCB/LCB and ASTM A350 LF2/LF3 are used, respectively, for cast and forged bodies.

As the temperature, the pressure, or the corrosion increase, stainless steel bodies become necessary: ASTM A351 CF8 (SS304) and CF8M (SS316) for cast devices, and the various ASTM A182 Fxx (F304, F316, F321, F347) for forged types.

For specific applications, special material grades with even stronger corrosion resistance are used, such as super austenitic stainless steels (SMO 254), duplex and super duplex steels (F44, F51, F53, F55), and nickel alloys (Inconel, Incoloy, Hastelloy).

For marine applications, non-ferrous materials or alloys are the elective choices, like Monel, Cupronickel, Aluminum-bronze alloys, and other alloys combining Nickel, Copper, and Aluminium. Cast iron bodies, which are the cheapest types, are used for water distribution (low-pressure applications).

The design of a valve body encompasses several key features:

Connections: Valve bodies are designed with various end connections to facilitate integration into piping systems. These connections can be flanged, threaded, welded, or socket welded, each suitable for different applications and pressure ratings.
Pressure Containment: The valve body is engineered to contain the operational pressures of the fluid it controls without leakage. Its thickness and material composition are calculated to withstand the maximum expected pressure and any thermal expansions.
Flow Path: Inside the valve body is the flow path, which can be straight-through or angular, determining the direction and characteristics of the fluid flow. The internal design, including cavities and ports, is optimized for minimal flow resistance and efficient operation.

The valve body houses several integral components crucial for valve operation, including:

Trim: The internal parts that come in direct contact with the fluid, such as the disc, seat, and stem. The trim regulates the flow and sealing within the valve.
Bonnet: The component that attaches to the valve body to enclose the internal parts. It can be bolted, screwed, or welded to the body.
Packing: A sealing system within the valve body that prevents fluid leakage around the stem.

In the oil and gas industry, the reliability and safety of operations heavily depend on the quality and integrity of valves. Valve bodies are therefore designed to meet stringent industry standards and certifications, such as API (American Petroleum Institute) and ASME (American Society of Mechanical Engineers), to ensure they can handle the demanding operational conditions. Their role in controlling the flow, pressure, and direction of petroleum products, natural gas, and by-products makes them indispensable components in exploration, production, refining, and distribution processes.

Body End Connections

Valves can be connected to other mechanical devices and pipes in different ways. The main end types are flanged and buttweld (for devices above 2 inches) and socket weld or threaded/screwed (NPT or BSP) for small-diameter devices. Butterfly valves have more articulated body-end types, like lug, wafer, and double-flanged ends.

Let’s now delve into the different types of valve bodies’s end types:

Flanged Ends

flanged valve

In this case, the device has two flanged ends that can be connected with a pipe by using a mating (companion) flange.

A flanged connection requires a proper number of stud bolts and nuts, as indicated by the ASME B16.5 specification, and a suitable gasket.

Flanged connections are common for larger-diameter valves, and they ensure long-lasting, and strong, joints.

The flange face may be raised, flat, ring joint, tongue, and groove male & female (the most common finish is the RF type, i.e. raised face), and be finished in any of the available variants (stock, serrated or smooth).

Socket Weld And Buttweld

socket weld valve — Socket weld valve end connections

Cast valve with socket connection — Buttweld valve end connections

Valves with socket weld ASME B16.11 or buttweld ends ASME B16.25 are welded to the connecting pipe.

Welded connections are more expensive to execute than flanged joints, as they require more work, but are more reliable and less prone to leakages in the long run.

Socket weld and buttweld ends are used for high-pressure pipelines (socket weld for smaller sizes, below 2 inches, and buttweld for larger diameters).

Buttweld connections require full welding of the beveled ends of the two parts to be joined, whereas socket weld connections are made by fillet welds.

Threaded End Connections

Threaded valve end

In this case, the device is connected to the pipe by a thread (tapered thread), which may be BSP or NPT (more common in the petrochemical industry).

This type of connection is used for low-pressure pipelines with bore sizes below 2 inches, not subject to mechanical forces such as vibration and elongation.

Threaded connections are quicker to execute and cheaper, as the pipe is simply screwed onto the valve, without the need for flanges, stud bolts, or welding operations.

In case of leakage, however, threaded connections need to be changed and can’t be repaired (which is instead possible for the two previous types of pipe-to-end connections).

BSP VS. NPT Threaded Connections

BSP (British Standard Pipe) and NPT (National Pipe Thread) are two of the most commonly used threaded connections for pipes and fittings, especially in the context of connecting valves, instruments, and plumbing components. Despite serving similar functions in creating secure threaded connections for fluid transport systems, they differ significantly in design, application, and compatibility. Understanding these differences is crucial for ensuring leak-proof and efficient piping systems, particularly in industries like oil and gas, water management, and manufacturing.

Design Differences between BSP and NPT threaded-ends:

Thread Form: NPT threads have a 60-degree thread angle with a tapered profile, which means the diameter of the threads increases or decreases along the length of the fitting. This taper creates a seal through the wedging action of the threads themselves, often requiring thread sealant or tape to ensure a leak-proof connection. In contrast, BSP threads come in two types: BSP Parallel (BSPP), with a straight or parallel thread profile, and BSP Tapered (BSPT), with a taper similar to NPT but with a 55-degree thread angle. The different angles and shapes affect how each thread type seals and mates with its counterpart.
Sealing Mechanism: NPT fittings rely on the interference fit between the male and female threads for sealing, necessitating the use of a sealant. BSPP connections, however, usually require a bonded seal or washer placed between the male and female ends for a leak-free seal, while BSPT connections can seal on the thread itself like NPT, though the thread profiles are not interchangeable.

Application and Compatibility:

Geographical Use: NPT is the standard thread type in the United States and Canada for connecting pipes and fittings in pneumatic, hydraulic, and plumbing systems. BSP threads are more common in Europe, Asia, Australia, and other parts of the world. While both types are used globally, their prevalence varies by region, influencing their selection based on local standards and availability.
Interchangeability: Due to their different thread angles and designs, NPT and BSP fittings are not directly interchangeable. Attempting to mate an NPT fitting with a BSP counterpart can result in damage to the threads, inadequate sealing, and potential leaks. Special adapters are required to connect NPT and BSP threaded components securely.

Choosing Between BSP and NPT:

Selecting between BSP and NPT threads depends on several factors:

Regional Standards and Availability: Choose the thread type that aligns with the local standards and is readily available in your region to ensure compatibility with existing systems and ease of replacement.
Application Requirements: Consider the specific requirements of your application, including the type of fluid, pressure, and the need for a reliable seal. For example, BSPP might be preferred for applications requiring a flat sealing surface, while NPT and BSPT are better suited for creating tighter seals in high-pressure systems.
System Design: The overall design of your piping or fluid transport system may dictate the choice of thread type, based on the connections used in existing components and the need for adapters or specific sealing methods.

Understanding the distinctions between BSP and NPT threaded connections is essential for engineers, plumbers, and technicians to make informed choices when designing and assembling piping systems. Proper selection and installation not only ensure system integrity and leak-free operation but also compliance with regional standards and practices.

VALVE BONNET

The valve bonnet is a critical component of a valve assembly, serving as the cover for the valve body. It is second in importance only to the valve body itself in the overall valve structure. The bonnet is attached to the valve body, which is the primary pressure-containing structure, and together, they enclose the internal parts of the valve that come into direct contact with the process fluid, such as the stem, disk, and seat. Let’s explore the functions, types, and significance of the valve bonnet in more detail:

Functions Of The Valve Bonnet

Pressure Containment: The bonnet acts as a seal, ensuring that the process fluid does not escape from the valve body. It is designed to withstand the maximum pressure of the valve’s intended use.
Component Protection: By enclosing the internal parts of the valve, the bonnet protects them from external contaminants and damage, contributing to the valve’s durability and reliability.
Access Point: The bonnet can serve as an access point for the maintenance, repair, or replacement of the valve’s internal components. Depending on the valve design, removing the bonnet may provide direct access to the internals.

Types Of Valve Bonnets

Valve bonnets come in various designs, each suited to different applications and pressure conditions. Common types include:

Bolted Bonnet: A widely used design where the bonnet is attached to the valve body with bolts or studs and nuts. It provides a sturdy seal and is suitable for a broad range of pressures and temperatures.
Screwed Bonnet: In this design, the bonnet is screwed directly into the valve body. Screwed bonnets are commonly used in smaller valves and lower-pressure applications.
Welded Bonnet: For valves used in high-pressure and high-temperature applications, a welded bonnet provides a leak-proof seal by permanently welding the bonnet to the valve body. This design is often used when the valve does not require regular maintenance.
Pressure Seal Bonnet: Used in high-pressure applications, this design employs a gasket that is pressure-energized to enhance the seal between the bonnet and the valve body as the internal pressure increases.
Union Bonnet: A design that allows for easy disassembly and reassembly of the valve for maintenance. The bonnet and body are connected with a threaded union, facilitating straightforward access to the valve internals.

Significance Of The Valve Bonnet

The valve bonnet plays a vital role in ensuring the safe and efficient operation of the valve. Its design and construction are critical for maintaining the integrity of the valve under operating conditions. Choosing the appropriate bonnet type based on the specific requirements of the application, such as pressure, temperature, and the need for maintenance access, is essential for valve performance and longevity.

In summary, the valve bonnet is an indispensable part of the valve assembly, contributing to pressure containment, protection of internal components, and, depending on its design, facilitating maintenance and repair activities. Its importance in the overall functionality and safety of the valve system cannot be overstated.

TRIM

The trim is a collective name for all the internal parts of the valve that can be removed and replaced (these parts are also called “wet”, as they are in direct contact with the conveyed fluid).

Typically, the trim includes components such as the disc, the seat, the stem, the glands, the bushings, and the sleeves needed to guide the stem (the actual list of components that make up the trim depends, actually, on the type of device).

Valve trim refers to the internal components of a valve that come into direct contact with the fluid being controlled. It plays a crucial role in the function and performance of the valve, affecting its ability to regulate flow, pressure, and temperature within a system. The trim essentially determines how the valve operates, including how it opens and closes, and how it modulates or throttles the flow of the process medium. Understanding the components that make up the valve trim and their functions is essential for selecting the right valve for specific applications and ensuring optimal performance and durability.

Components Of Valve Trim

The main components of valve trim include:

Disc or Ball: The component that actually blocks the flow path or allows flow through the valve. In globe and gate valves, this is typically a disc; in ball valves, it’s a ball with a hole through the center.
Seat: The seat provides a sealing surface for the disc or ball to rest against when the valve is closed. The quality and material of the seat are crucial for ensuring a tight seal and preventing leakage.
Stem: The stem connects the actuator or handle to the disc or ball and transmits the motion required to open or close the valve. It can move linearly (in globe or gate valves) or rotate (in ball or butterfly valves).
Cage: In some valve designs, particularly in globe valves, the cage surrounds the disc and can guide its movement as well as provide additional flow control and stability.
Spring: Springs may be used in some valve trims, particularly in check valves and safety valves, to provide the necessary force for opening or closing the valve under certain conditions.
Plug: In some types of valves, like plug or globe valves, a plug may serve as the obstructing element instead of a disc or ball.

Importance Of Valve Trim

Flow Control: The design and material of the valve trim directly influence the valve’s ability to control the flow rate, direction, and pressure drop across the valve. Different trim designs cater to different control needs, from simple on/off to precise flow regulation.
Durability and Wear Resistance: The trim components are subject to continuous wear due to their contact with the process fluid. Selecting trim materials that are compatible with the fluid and operating conditions (such as temperature and pressure) is essential to ensure the valve’s longevity and reliability.
Maintenance and Replacement: Over time, parts of the valve trim may need maintenance or replacement due to wear or damage. The design of the trim affects the ease with which these maintenance activities can be carried out. Modular trim designs allow for easier replacement of worn components.
Selecting The Right Valve Trim

Choosing the appropriate valve trim requires careful consideration of several factors, including the nature of the fluid (its corrosiveness, viscosity, and presence of solids), the required flow control characteristics, and the operating conditions (pressure and temperature). The right trim material and design ensure that the valve performs effectively and efficiently over its intended lifespan, minimizing maintenance needs and operational downtime.

Typical trim combinations for gate, globe, and check valves have been standardized by the API trim chart.

In summary, valve trim is the collective term for the internal components of a valve that interact with the fluid being controlled. Its design and material composition are critical for ensuring the valve’s effective operation, durability, and ability to meet specific flow control requirements.

DISC

The valve disc is a fundamental component within the valve trim, playing a critical role in the valve’s function of regulating, stopping, or starting the flow of fluid.

It interacts directly with the fluid path, and its movement—either towards or away from the valve seat—controls the flow through the valve. The design, material, and proper functioning of the valve disc are vital for ensuring the valve’s effectiveness and reliability in various applications, ranging from simple water piping systems to complex chemical processing plants.

Functionality Of The Valve Disc

Flow Regulation: The primary function of the valve disc is to regulate the flow of fluid through the valve. By moving closer to or further from the valve seat, the disc alters the size of the opening through which the fluid can pass, thereby controlling the flow rate.

Sealing: When fully engaged with the seat, the disc provides a tight seal that prevents fluid from passing through the valve, achieving a complete shutoff. The efficiency of this seal is crucial for preventing leaks and ensuring the safety and efficiency of the system.

Modulation: In some valve types, such as globe or control valves, the disc can be positioned to precisely control the flow rate, allowing for fine modulation of the process fluid. This capability is essential in applications where maintaining specific flow parameters is critical.

Types Of Valve Discs

The specific design of a valve disc can vary depending on the type of valve and its intended application. Common types include:

Flat Discs: Used in gate valves, flat discs move vertically to the flow direction, providing an on/off function by either completely blocking or allowing flow.

Ball Discs: In ball valves, the disc is a sphere with a hole through its center. Rotation of the ball opens or closes the flow path, offering both shutoff and throttling capabilities.

Plug Discs: Utilized in plug valves, these discs are cylindrical or conically tapered plugs that rotate to control flow through an opening in the plug.

Butterfly Discs: Butterfly valves use a flat, circular disc that pivots in the center of the valve body. This design allows for quick operation and is used for both isolation and flow regulation.

Material Considerations

The material of the valve disc is selected based on the fluid characteristics (such as corrosiveness, temperature, and pressure), the valve’s application, and the desired longevity. Common materials include:

Metals: Stainless steel, carbon steel, brass, and bronze are widely used for their strength, durability, and resistance to high temperatures and pressures.

Plastics: For applications involving corrosive fluids or lower pressure and temperature conditions, plastics such as PVC, PTFE (Teflon), and PVDF offer excellent corrosion resistance and reduced cost.

Ceramics: Employed in applications involving abrasive fluids, ceramic discs provide superior wear resistance.

Significance Of The Disc For Valves’s Performance

The valve disc is a pivotal component within the valve’s architecture, instrumental in controlling fluid flow, ensuring tight shutoff, and enabling precise flow modulation. Its design, material, and compatibility with the valve seat are critical for the valve’s performance, efficiency, and durability in various industrial and residential applications. Selecting the right valve disc requires a thorough understanding of the application requirements, including the fluid’s nature, operational conditions, and desired control characteristics.
SEATS

Valve seats are integral components of a valve’s internal mechanism, designed to interface with the valve disc (or plug, ball, etc.) to form a tight seal that controls or stops fluid flow through the valve.

These seats play a pivotal role in ensuring the efficiency, reliability, and leakage prevention of the valve during operation. The material composition, design, and condition of the valve seats are critical to the valve’s performance, affecting its ability to regulate flow accurately and maintain a secure seal under various operating conditions.

Function And Importance

Sealing Surface: The primary function of a valve seat is to provide a smooth, precise surface for the valve disc to rest against, creating a seal that prevents fluid from leaking past the closed valve.

Flow Regulation: In valves designed for throttling, the seat works in conjunction with the disc to modulate the flow of fluid. The design of the seat can influence flow characteristics and control precision.

Durability and Wear Resistance: Valve seats must withstand continuous contact with the valve disc and resist wear and deformation from the process fluid, pressure fluctuations, and mechanical operations.

Seats Materials

Valve seats are made from a variety of materials, chosen based on the application’s specific requirements, including the type of fluid, operating pressure, temperature, and corrosive potential. Common materials include:

Metals: Stainless steel, bronze, and brass are commonly used for their durability and resistance to high temperatures and pressures. Hardened metals or alloys may be used in severe service conditions for enhanced wear resistance.

Soft Seats: Materials such as PTFE (Teflon), nylon, and other elastomers offer excellent sealing capabilities and resistance to chemical corrosion. Soft seats are used in applications where metal seats might not provide an adequate seal, but they are generally limited to lower temperature and pressure conditions.

Ceramics: For high-wear or corrosive applications, ceramic seats offer superior hardness, wear resistance, and stability under extreme temperatures.

Design Considerations

The design of the valve seat is crucial for its function and longevity. Factors to consider include:

Seat Shape and Angle: The contour and angle of the seat affect the sealing efficiency and flow characteristics. Seats can be designed for linear or equal percentage flow characteristics in control valve applications.

Interchangeability: Some valve designs feature replaceable seats, allowing for easy maintenance and extended valve life. These seats can be swapped out when worn or damaged without replacing the entire valve.

Sealing Method: The seat-to-disc contact area and method of sealing (e.g., metal-to-metal, soft seal) determine the tightness of the seal and the valve’s suitability for specific applications.

Special Treatments For Valve Seats

Valve seats are integral components of valve assemblies, providing a sealing surface against which the valve disc or plug seals to stop the flow of fluid. The performance and longevity of a valve largely depend on the condition and material of the valve seat, as it must withstand the mechanical stresses and corrosion caused by the flowing medium. To enhance their durability, wear resistance, and sealing capabilities, valve seats may undergo various special treatments. These treatments are designed to ensure that the valve operates reliably over its intended lifespan, even under harsh operating conditions. Here are some common treatments available for valve seats:

Hardening Treatments

Surface Hardening: Processes like induction hardening and flame hardening increase the surface hardness of the seat, improving wear resistance without compromising the toughness of the base material.

Case Hardening: Techniques such as carburizing, nitriding, and carbonitriding add a hard, wear-resistant layer to the surface of the seat while maintaining a ductile interior. These treatments are particularly useful for seats in valves handling abrasive particles.

Coating Treatments

Stellite Overlay: Stellite, a cobalt-chromium alloy, is known for its excellent hardness and resistance to wear and corrosion. Applying a Stellite overlay on valve seats can significantly extend their service life, especially in high-pressure, high-temperature, and erosive applications.

Chrome Plating: Chromium plating offers good wear resistance and low friction, making it suitable for valve seats in applications where minimizing leakage is critical.

Nickel Alloy Coatings: Nickel-based coatings, including Inconel and Monel, provide enhanced corrosion resistance in environments with corrosive fluids or gases.

Thermal Spray Coatings: Techniques like High-Velocity Oxygen Fuel (HVOF) spraying can apply tungsten carbide or other hard materials onto the seat surface, improving wear and corrosion resistance.

Material Upgrades

Solid Seats: In some cases, the entire seat is made from a high-performance material, such as ceramics or high-nickel alloys, to withstand extreme conditions of temperature, pressure, and corrosion.

Inserts: Using inserts made from durable materials like ceramics or hardened metals can offer superior wear and corrosion resistance. These inserts are either pressed or screwed into the valve body.

Lapping And Grinding

Precision Lapping: This process involves rubbing the seat against a flat surface with an abrasive compound to achieve a high degree of surface finish and flatness. Lapping ensures a tight seal between the seat and the disc or plug.

Grinding: Grinding processes can be used to restore damaged or worn seats, improving the sealing surface’s condition and extending the valve’s operational life.

Each treatment has its specific advantages and is chosen based on the valve’s application, the characteristics of the fluid it controls, and the operating conditions (pressure, temperature, and presence of abrasive particles). By selecting the appropriate treatment for valve seats, manufacturers and users can ensure optimal performance, reduce maintenance costs, and extend the lifespan of valves in various industrial and commercial applications.

Importance Of Valve Seats

Valve seats are crucial for the functionality and performance of valves, acting as the sealing interface that regulates fluid flow and ensures leak-free operation. The selection of seat material and design is tailored to the valve’s intended use, considering factors such as fluid compatibility, pressure and temperature conditions, and required flow control characteristics. Proper maintenance and timely replacement of valve seats are essential for maintaining optimal valve performance and system integrity.

STEM

The stem of a valve is used to open/close the fluid as it moves the disc. The stem is linked to the valve actuator or to the manual handwheel (or lever), at one end, and is connected to the valve disc on the other end.

For the gate and globe types, the stem operates a linear motion on the disc, whereas, for the ball, butterfly, and plug types, the disc rotates to open or close the device (“quarter turn valves”).

Stems are made of forged steel and are connected to the disc by threading or other means. A proper finish of the stem surface is necessary to prevent leakages.

There are five main types of stems:

Rotary: This is a standard type of ball, plug, and butterfly valve. A quarter-turn motion of the stem is needed to open/close the device

Sliding: In this case, the stem does not execute any rotation. The stem slides in and out the valve to open or close it. This design is common in hand-operated lever rapid-opening valves. It is also used in control valves are operated by hydraulic or pneumatic cylinders.

Rising type with outside screw and yoke (“OS&Y”): the external side of the stem is threaded while the part of the stem which is inside the valve is plain. The threads of the stem are isolated from the medium by the packing. Two alternative designs are available. The “OS&Y” design is common for valves above 2″.

Rising type with an inside screw (“IS&Y”): The threaded part of the stem is positioned inside the valve body, whereas the stem packing lays outside. With this design, the stem threads are in touch with the medium flowing through the pipeline. Once rotated, the stem and the hand wheel rise together and open the valve.

Non-rising stem type with inside screw: The threaded part of the stem is inside the valve and does not rise. The valve disc floats on the stem, like a nut if the stem is rotated. Stem threads are in contact with the media of the pipeline, and as such, may be exposed to its corrosive impact. This is the reason why such a design is used when the available space to position the valve is too narrow to permit linear movement, and the media does not cause erosion, corrosion, or abrasion of the stem material.

PACKING

The gasket that seals the stem with the bonnet is called packing and comprises the following components:

Gland follower, which is a sleeve that compresses the packing, by a gland into the stuffing box.

Gland is a type of bushing, which compresses the packing into the stuffing box.

A stuffing box is a chamber in which the packing gets compressed.

Packing is available in different materials, like PTFE, elastomers, fibrous material, etc.

A backseat is sitting inside the bonnet. The back seat provides a seal between the stem and bonnet and prevents system pressure from building against the valve packing once the valve is fully open. Back seats are often used in gate and globe valves.

The valve packaging shall be properly designed and manufactured to minimize the possible damage to the stem and minimize the risk of leakages of fluids. On the other hand, it is necessary to observe that a too-tight packing may affect the stem.

VALVE ACTUATOR

Valve actuators are devices used to operate valves automatically or manually, converting control signals into mechanical motion to open, close, or modulate the flow of fluids.

The choice of the right actuator for a valve depends on several factors, including the valve size, the required speed of operation, the force needed to operate the valve, environmental conditions, and whether the actuator will be used for on/off, throttling, or proportional control. There are several types of valve actuators, each with its own set of characteristics, advantages, and applications.

Key Types Of Actuators

Manual Actuators

Manual actuators require human effort to operate the valve, using handwheels, levers, or gears. They are simple and do not rely on an external power source.

Advantages: Simplicity, no need for power supply, and direct control.

Applications: Used in applications where automated control is not necessary or as a backup method for operating valves.

A hand-operated or manual valve is generally equipped with a hand wheel that can be rotated clockwise or counter-clockwise to open and/or close the valve (typical for gate and globe valves). Ball, plug, or butterfly are actuated using a lever (manual quarter turn valves).In the following cases, it is not either possible nor advisable to use manual valves:

Large dimension valves that operate at high pressures

Valves that need to be controlled from a remote location

Valves that require, for the nature of the process, a very fast open or close operation

In all these cases, a valve actuator is needed. The actuator produces linear and rotary motion able to open or close a valve (the actual movement depends of course on the type of the valve, linear or quarter turn).

Pneumatic Actuators

Pneumatic actuators use compressed air to generate motion to operate the valve. They are one of the most common types of actuators used in industrial environments due to their simplicity, reliability, and cost-effectiveness.

Advantages: Rapid response time, inherent explosion safety, and simplicity of design.

Applications: Widely used in the oil and gas, chemical, water treatment, and manufacturing industries.

Hydraulic Actuators

Hydraulic actuators use pressurized fluid, typically oil, to move the valve. They can produce a high amount of force in a relatively small footprint, making them suitable for large valve operations.

Advantages: High force output, precise control, and good for heavy-duty applications.

Applications: Ideal for use in environments where a high force is required, such as in the power generation and offshore industries.

Electric Actuators

Electric actuators use an electric motor to drive the valve to the desired position. They can be easily integrated with electronic control systems for accurate positioning and feedback.

Advantages: Precise control, easy integration with control systems, and suitable for remote operation.

Applications: Commonly used in HVAC, water treatment, and light industrial applications.

Electro-Hydraulic Actuators

Electro-hydraulic actuators combine electric and hydraulic technologies. An electric motor drives a hydraulic pump, which then moves the actuator to operate the valve.

Advantages: Combines the precision of electric actuators with the power of hydraulic actuators, suitable for remote and automatic control.

Applications: Useful in applications requiring precise control and high force, such as in large valve operations and safety shutdown systems.

Gas Over-Oil Actuators

A gas-over-oil actuator is a type of valve actuator designed for the automation of valve operations, leveraging a combination of high-pressure gas and hydraulic oil to generate the force necessary for valve movement. This actuation method is particularly favored in the oil and gas industry, especially for remote pipeline applications or in environments where electrical power is scarce or non-existent. Here’s how it works and why it’s beneficial:

How It Works

Mechanism: In a gas-over-oil actuator, pressurized gas (often natural gas from the pipeline itself) is used to exert force on a hydraulic fluid (oil), which is then directed to move the actuator piston. This piston movement is mechanically linked to a valve, enabling it to open, close, or modulate the flow as required.

Components: The actuator typically consists of a gas pressure chamber, an oil reservoir, control valves for directing the flow of gas and oil, and a piston or diaphragm that converts the pressure into mechanical motion.

Advantages

Remote Operation: Since they can utilize the pipeline gas itself as a power source, gas-over-oil actuators are ideal for remote locations where electrical power is unavailable.

Safety: They are inherently safe for use in explosive atmospheres, as they do not require electricity and minimize the risk of ignition.

Reliability: This type of actuator is known for its reliability and durability, capable of operating in harsh environments with minimal maintenance.

Applications

Pipeline Valves: Widely used for the control and safety shutdown valves in natural gas pipelines.

Offshore Platforms: Suitable for valve actuation in offshore gas extraction platforms, where reliability and safety are paramount.

Isolated Installations: Ideal for any valve actuation application in remote or difficult-to-access locations within the oil and gas sector.

Gas-over-oil actuators provide a robust and reliable solution for valve automation, combining the advantages of hydraulic systems’ power and precision with the safety and availability of using pipeline gas as a power source. This makes them an essential component in the infrastructure of modern oil and gas extraction and transportation systems.

Solenoid Actuators

Solenoid actuators use electromagnetic solenoids to operate the valve. They are typically used for on/off control in smaller valve applications.

Advantages: Fast response time, simple design, and suitable for small valves.

Applications: Commonly used for precise control in fluid power systems, medical equipment, and general on/off applications in various industries.

Each type of valve actuator offers distinct advantages and is chosen based on the specific requirements of the application, such as control needs, operating environment, and valve size. Understanding the different types of actuators and their capabilities is crucial for selecting the right actuator to meet the demands of a particular system or process.

Rotork and Auma actuators have the largest market shares within the petrochemical industry.

May 23, 2024/by stvvalve

industry valve news, News

Understand Gate Valves (API 600, 602, 603)

What is a gate valve? It is a shut-off device to open and close the flow of the fluid conveyed by a piping system (or a pipeline). A gate valve is a bi-directional valve, as the fluid may flow in either direction. The installation of this type of valve creates a modest pressure drop in the pipeline, lower than globe valves. Gate valves have forged bodies for bore sizes below 2 inches (API 602/BS 5352), and cast bodies for larger sizes (API 600, API 603, API 6D).

GATE VALVES

WHAT IS A GATE VALVE?

In the oil and gas industry, a gate valve is a crucial component used to control the flow of fluids through pipelines and equipment. Characterized by its ability to provide a straight-through, unrestricted flow path when fully open, a gate valve operates by lifting a gate (or wedge) out of the path of the fluid.

This type of valve is typically used for on/off control rather than flow regulation, making it ideal for applications where a minimal pressure drop and a full bore are required when the valve is in the open position.

Gate valves are on-off valves to open and close the flow of the fluid in a pipeline. The valve is opened and/or closed by the vertical movement of a disc on the valve’s seat.

Gate valve API 600

GATE VALVES ADVANTAGES & DISADVANTAGES

Bi-Directional: Gate valves can control flow in both directions, offering versatility in installation and use.
Minimal Pressure Drop: When fully open, gate valves provide a straight path for flow, resulting in a very low-pressure drop across the valve.
Sealing Surface: Gate valves have two sealing surfaces between the gate and seats, providing a tight seal when the valve is closed.
Operation: These valves are operated using a handwheel, gear, actuator, or motor, depending on the size, pressure rating, and application requirements. Manual operation is common for smaller sizes, while larger valves often require mechanical assistance.
Easy to maintain and disassemble
Low-cost option
Can be used with slurries and viscous liquids
Available in large sizes
Inherently fire-safe (when used with a metal sheet)

The disadvantages of gate valves are:

Slow open and close time
Low-pressure limitations
Erosion of the seat and disk can occur
Poor throttling characteristics
May be difficult to repair in case of failure (it is easier and cheaper to replace a broken cast valve in most cases)
TYPICAL APPLICATIONS IN THE OIL&GAS INDUSTRY

Gate valves are largely used in the oil & gas, petrochemicals, and general manufacturing industries. The most common tasks assigned to this type of valve are:
- Isolation Tasks: Gate valves are widely used for isolation purposes in oil and gas pipelines, storage tanks, and processing equipment, allowing sections of a system to be shut down for maintenance or in an emergency without affecting the rest of the operation.
- High-Pressure Environments: Their robust design makes them suitable for high-pressure and high-temperature applications commonly found in upstream exploration and production, as well as in downstream processing.
- Underground Installations: Due to their full-bore design and minimal pressure drop, gate valves are also preferred for underground gas storage and control applications.
SELECTION CRITERIA

When selecting a gate valve for oil and gas applications, several factors should be considered:
- Material: The choice of material depends on the type of fluid, operating temperatures, and pressures. Common materials include carbon steel, stainless steel, and alloy steel designed to withstand corrosive environments.
- Size and Pressure Rating: Proper sizing and selection of pressure ratings are essential to match the pipeline specifications and operational conditions.
- Maintenance: While gate valves are known for their durability, they are not ideally suited for throttling applications, as the vibration and rapid flow changes can cause wear to the gate and seats, leading to leakage. Regular maintenance is required to ensure long-term reliability and performance.
APPLICABLE SPECIFICATIONS (API, ASME)

API SPECS FOR GATE VALVES

API (American Petroleum Institute) specifications provide comprehensive standards and technical requirements for the design, manufacturing, and testing of gate valves used in the oil and gas industry. These specifications ensure the reliability, safety, and efficiency of gate valves under various operational conditions.

Below are some key API specifications applicable to gate valves:

API 600: applies to carbon/alloy steel gate valves

“Steel Gate Valves – Flanged and Butt-Welding Ends, Bolted Bonnets” This specification covers the design, manufacturing, and testing of bolted bonnet steel gate valves for petroleum and natural gas industries. It includes detailed requirements for gate valves with flanged or butt-welding ends and bolted bonnets, focusing on sizes and pressure classes specified for use in pipeline and piping systems.

API 603: applies to stainless steel gate valves

“Corrosion-Resistant, Bolted Bonnet Gate Valves – Flanged and Butt-Welding Ends” This standard covers corrosion-resistant bolted bonnet gate valves with flanged or butt-welding ends. API 603 focuses on valves made from stainless steel and other alloys intended for corrosion resistance, detailing requirements for various design features, pressure classes, and sizes.

API 602/BS 5352: applies to forged steel gate valves

“Compact Steel Gate Valves – Flanged, Threaded, Welding, and Extended-Body Ends” API 602 specifies the requirements for compact steel gate valves with a variety of end connections, including flanged, threaded, and welding ends. It is intended for smaller-sized valves (NPS 4 and smaller) used in high-pressure applications, offering guidance on materials, design, and testing criteria.

API 6D: applies to slab and through conduit valves for pipelines

“Pipeline and Piping Valves” API 6D is a broad specification that covers the design, manufacturing, and testing of valves for pipeline applications, including gate valves. It encompasses aspects such as end-to-end dimensions, pressure testing, and marking for valves intended to be used in pipeline systems for transporting petroleum and natural gas.

API 6FA

“Specification for Fire Test for Valves” While not exclusively for gate valves, API 6FA specifies fire test requirements for valves used in petroleum and natural gas industries. It provides a method for testing valve performance when exposed to fire, ensuring that valves can maintain structural integrity and leak tightness during and after a fire incident.

API 624

“Type Testing of Rising Stem Valves Equipped with Graphite Packing for Fugitive Emissions” API 624 addresses the testing of rising stem gate valves equipped with graphite packing, focusing on their performance regarding fugitive emissions. This specification ensures that valves meet environmental and safety standards by limiting emissions of volatile organic compounds (VOCs).

API-598: valves testing

ASME/ANSI SPECS FOR GATE VALVES

ASME (American Society of Mechanical Engineers) and ANSI (American National Standards Institute) specifications play critical roles in standardizing the design, manufacturing, and testing of gate valves, ensuring their safety, reliability, and efficiency across various industries. Here are some key ASME/ANSI specifications applicable to gate valves:

ASME B16.34 – Valves – Flanged, Threaded, and Welding End

This standard provides requirements for materials, pressure-temperature ratings, dimensions, tolerances, marking, and testing for flanged, threaded, and welding end steel valves. It includes gate valves among other valve types and serves as a fundamental reference for valve specifications in terms of pressure class ratings, material groups, and appropriate service conditions.

ASME B16.10 – Face-to-Face and End-to-End Dimensions of Valves

ASME B16.10 specifies the standard face-to-face and end-to-end dimensions for flanged, threaded-end, welding-end, and wafer-type valves, including gate valves. This standard is crucial for ensuring the interchangeability and proper fit of valves within piping systems.

ASME B16.5 – Pipe Flanges and Flanged Fittings

Although not exclusively for valves, ASME B16.5 establishes dimensions, tolerances, and material specifications for pipe flanges and flanged fittings in sizes from NPS 1/2 through NPS 24. Gate valves with flanged ends must comply with this specification to ensure compatibility with flanged piping connections.

ASME B16.25 – Buttwelding Ends

This specification outlines the dimensions, tolerances, and finishing for buttwelding ends of piping components, including gate valves. It ensures the proper fit and sealing capability for welded connections in piping systems.

ASME ANSI B16.47: flanged ends for bore sizes above 24 inches

ASME B31.4 – Pipeline Transportation Systems for Liquids and Slurries

While ASME B31.4 is a piping code rather than a specific valve standard, it includes requirements that affect the selection and application of gate valves in pipeline systems transporting liquids and slurries. It provides guidelines for materials, design, construction, and testing of pipeline components.

ASME B31.8 – Gas Transmission and Distribution Piping Systems

Similar to ASME B31.4 but focused on gas transmission and distribution, ASME B31.8 also impacts the use of gate valves in gas pipelines, specifying criteria for material selection, design, construction, and testing to ensure safety and integrity in gas piping systems.

Compliance with these ASME/ANSI specifications is essential for gate valve manufacturers and users, as it guarantees that valves meet established industry standards for performance, durability, and safety. These standards help guide engineers and project managers in selecting the appropriate gate valves for their specific applications, whether for water treatment, oil and gas, chemical processing, or other industrial systems.

GATE VALVE TYPES

CAST STEEL GATE VALVES

This is the most common type, covered by the API 600 (carbon and alloy steel) and API 603 (stainless steel and higher grades) specifications. Cast steel gate valves are available in sizes above 2 inches, and up to 80 inches.

Cast steel gate valves are essential components in various industrial applications, including oil and gas, power generation, and water treatment systems. These valves are designed for on/off control of fluids and are particularly favored for their capability to provide a minimal pressure drop when fully open. Cast steel, used in the construction of these valves, offers a robust and durable solution suitable for high-pressure and high-temperature environments.

Construction And Operation

Cast steel gate valves consist of a valve body, bonnet, stem, gate (or wedge), and sealing elements. The body and bonnet are typically made from cast steel through a casting process where molten steel is poured into a mold and allowed to solidify. This method provides the flexibility to create complex shapes and sizes, making it possible to tailor the valve design to specific application requirements.

The gate, manipulated by the stem, moves vertically within the valve body to open or close the flow path. When raised, the gate allows for an unrestricted flow, and when lowered, it sits tightly against the valve seat to block the flow, ensuring a tight seal.

Key Features

Durability: Cast steel provides excellent strength and toughness, making these valves suitable for high-pressure and temperature applications.
Leakage Prevention: Properly designed and maintained cast steel gate valves offer excellent sealing capabilities, minimizing the risk of leakage.
Versatility: Available in various sizes and pressure ratings, cast steel gate valves can accommodate a wide range of fluids and service conditions.
Maintenance: While generally reliable, these valves require regular inspection and maintenance to ensure optimal performance, particularly in applications involving suspended solids that might cause wear or obstruction.

Applications

Cast steel gate valves are widely used across multiple industries for their ability to control the flow of liquids, gases, and vapors. Some common applications include:

Oil & Gas: For controlling the flow in pipelines and processing facilities.
Power Generation: In steam and water systems where high pressure and temperature are common.
Water Treatment and Distribution: For isolating sections of the system for maintenance or in response to system demands.

Selection Considerations

When selecting a cast steel gate valve, several factors should be considered to ensure it meets the operational requirements effectively:

Size and Pressure Rating: Match the valve size and pressure rating with the pipeline specifications and operational pressures.
Material Compatibility: Ensure the cast steel material is compatible with the fluid medium, considering factors like corrosion resistance and material strength at operating temperatures.
Operation Type: Choose between manual, electric, pneumatic, or hydraulic actuation based on the application and accessibility.
Standards and Certifications: Valves should meet relevant industry standards and certifications to ensure quality and safety in operation.

In summary, cast steel gate valves are a reliable choice for managing fluid flow in industrial systems, offering durability and versatility for a broad range of applications. Proper selection, based on the specific requirements of the application, ensures their effective and safe operation.

FORGED STEEL GATE VALVES

Forged steel valves are used for small bore piping, generally below 2 inches in diameter. The API 602 and BS 5352 specifications cover this type of gate valve.

Forged steel gate valves are integral components in a wide array of industrial systems where robust control of fluid flow is required. These valves utilize a gate mechanism to allow or block the flow of fluids, making them suitable for on/off service rather than flow regulation. Forged steel, as the material of choice for these valves, offers superior strength, durability, and resistance to high pressures and temperatures compared to cast steel counterparts. This makes forged steel gate valves especially valuable in high-demand environments such as the oil and gas, chemical processing, and power generation industries.

Construction And Features

Forged steel gate valves are constructed from steel that has been forged under high pressure to enhance its mechanical properties. The forging process aligns the grain structure of the steel, making it denser and more uniform. This results in a valve body with exceptional strength, improved impact toughness, and greater resistance to fatigue and thermal stresses.

Key features of forged steel gate valves include:

Enhanced Durability: The forging process gives the steel enhanced strength and toughness, enabling the valve to withstand high pressures and temperatures.
Tight Seal: When closed, the gate or wedge of the valve fits snugly against the valve seats, providing a tight seal that prevents fluid leakage.
Low Flow Resistance: In the fully open position, the valve provides a straight path for the flow, resulting in minimal pressure drop.
Versatility: Forged steel gate valves are available in various sizes, pressure classes, and end connection types, making them suitable for a broad range of applications.

Applications

Forged steel gate valves are used in demanding applications where high strength and durability are paramount. Typical applications include:

High-Pressure Systems: Such as those found in oil and gas production, where the valves must handle high-pressure and corrosive fluids.
Steam Services: In power plants and other settings where steam is used for power generation or heating, requiring valves that can withstand high temperatures and pressures.
Process Industries: Chemical manufacturing and processing plants use these valves to control the flow of aggressive and hazardous chemicals.
General Industrial Applications: Anywhere that requires reliable isolation of fluid flow under high pressure or temperature conditions.

Selection Considerations

Selecting the right forged steel gate valve involves several considerations:

Pressure and Temperature Ratings: Choose a valve that meets or exceeds the maximum expected system pressure and temperature.
Material Compatibility: The material of the valve should be compatible with the fluid it will control, considering factors such as corrosion and chemical reactivity.
Size and End Connections: The valve size should match the pipeline specifications, and the end connections (flanged, threaded, butt weld, etc.) should be compatible with the existing piping.
Standards and Certifications: Ensure the valve meets relevant industry standards and certifications for safety and performance.

Conclusion

Forged steel gate valves offer a reliable solution for high-pressure and high-temperature applications across various industries. Their construction from forged steel ensures superior strength, durability, and performance in challenging environments. When selecting a valve, it’s crucial to consider the specific requirements of the application to ensure optimal performance and safety.

API 6D GATE VALVES FOR PIPELINES (THROUGH-CONDUIT)

API 6D gate valves are specialized valves designed to meet the rigorous standards set by the American Petroleum Institute (API) for use in pipeline applications.

The API 6D specification covers the design, manufacturing, and testing of gate valves, as well as other pipeline valves such as ball, check, and plug valves, intended primarily for the oil and gas industry. These valves play a crucial role in controlling the flow of oil, gas, and other hydrocarbon products within pipeline systems, offering reliable operation in on/off service.

Key Features Of API 6D Gate Valves

Design and Construction: API 6D gate valves are designed to withstand the operational pressures and temperatures encountered in oil and gas pipelines. They feature robust construction and can be made from various materials to suit different environmental conditions and fluid properties.
Double Block and Bleed (DBB) Capability: Many API 6D gate valves offer double block and bleed functionality, allowing for the isolation of a section of the pipeline and the draining or venting of the space between the two sealing surfaces (gates), enhancing operational safety and maintenance procedures.
Sealing and Seat Design: These valves typically include soft or metal-to-metal sealing mechanisms to ensure tight shut-off and minimize leakage. The seat design is critical for ensuring the valve’s reliability and performance under high pressure.
Emergency Sealant Injection: Some API 6D gate valves are equipped with an emergency sealant injection feature, which allows for the injection of a sealant into the seating area in case of leakage, providing a temporary or emergency seal.
Full Bore Design: API 6D gate valves often feature a full bore design, meaning the diameter of the valve opening matches the diameter of the pipeline. This design minimizes pressure drop and allows for the easy passage of pipeline inspection gauges (pigs).

Applications

API 6D gate valves are extensively used in the oil and gas industry, particularly in pipeline systems for:

Transmission Pipelines: Controlling the flow and providing isolation capabilities in long-distance pipelines transporting oil and gas from production sites to refineries or storage facilities.
Distribution Networks: Managing the distribution of gas to residential, commercial, and industrial end-users.
Offshore Platforms and Processing Plants: Offering reliable isolation in the challenging conditions of offshore oil and gas extraction and processing.

Selection Considerations

When selecting an API 6D gate valve for a pipeline application, it’s important to consider:

Pressure Class and Size: The valve must be suitable for the pipeline’s operating pressure and diameter.
Material Compatibility: The valve material should be compatible with the fluid being transported, considering factors like corrosion resistance and temperature tolerance.
Operational Requirements: Consider whether manual, electric, pneumatic, or hydraulic actuation is needed based on the valve’s location and the system’s operational demands.

Types Of API 6D Gate Valves

PRESSURE SEAL API 6D TYPE

Pressure seal gate valves are used for high-pressure applications. The most common types of valves for high-pressure applications are the flexible wedge and the parallel slide pressure seal valve. They are generally available with cast or forged bodies, in dimensions from 2 to 24 inches, and pressure ratings from 600# to 4500#, with socket weld or buttweld, ends to ensure tight flanged joint connections (but flanged ends are also possible).

KNIFE TYPE API 6D Gate Valve

Knife gate valves were originally introduced within the pulp and paper industry, where standard shut-off valves could not properly operate due to the nature of the fluids conveyed during the paper production process.

Knife valves should never be used as modulating valves (to regulate the flow) as the fluid flowing through a partly closed valve would generate vibration and erode both the disk and the seat.

Therefore, knife valves should be used completely closed or opened like any other type of gate valve (globe valves are recommended to regulate the flow).

Lastly, to protect the valve against the impact of the water hammer effect, knife valves feature a very slow opening and closing speed.

A Knife valve can be manufactured in materials from ductile iron to stainless steel and in sizes between 2 and 24 inches (generally with cast bodies) with low-pressure ratings (< 300 lbs).

There are many different variants of knife valves, such as the soft-seated (resilient type, with elastomer seats) the metal seated (the seat and the disc generate a metal-to-metal seal), the slide gate, and bonneted types.

Soft seat knife gate valve.

A metal seated knife gate valve (left) and resilient, a soft-seated valve (right side).

The differences with standard design are:

A standard valve is available with flanged, butt weld, and socket weld connections (knives have lugged or wafer connections mainly)
A standard valve has a V-ring packing set that seals the shaft that is attached to the gate. Knife valves feature instead of a packing gland area that seals around the gate
Gate valves are bidirectional, whereas the knife type is generally uni-directional
A knife valve has a smaller profile than the ANSI gate valve, which is more bulky and refined
Knife gate valves are lighter and cheaper than API and ASME types

Conclusion API 6D Gate Valves

API 6D gate valves are essential components in the oil and gas industry, providing critical control and isolation functions within pipeline systems. Their design and construction adhere to stringent standards, ensuring reliability, safety, and efficiency in the transportation of hydrocarbon products. When selecting these valves, it’s crucial to match the valve’s specifications with the specific requirements of the pipeline system to ensure optimal performance.

GATE VALVE VS. OTHER TYPES OF VALVES

GATE VALVE VS. BALL VALVE

What is the difference between a gate and a ball valve?

Gate valves and ball valves are two of the most commonly used types of valves in various piping systems. Each has its own unique design, operation method, and advantages, making them suitable for specific applications.

Understanding the differences between these two valve types is crucial for selecting the right valve for a given system.

Design And Operation

Gate Valve: A gate valve features a flat gate or wedge that moves perpendicularly to the direction of flow. To open or close the valve, the gate is raised or lowered by turning a handwheel or actuator. When fully open, gate valves offer a straight-through flow path with minimal resistance, making them ideal for on/off control rather than flow regulation.
Ball Valve: A ball valve uses a spherical ball with a hole (bore) through its center. Rotating the ball 90 degrees around its axis opens or closes the flow path. In the open position, fluid flows through the bore. Ball valves provide excellent sealing and are used for both on/off control and throttling.

Applications

Gate Valves: Due to their ability to provide minimal flow restriction when fully open, gate valves are often used in applications where a free flow of fluid is necessary and where the valve will remain either fully open or fully closed most of the time. They are commonly found in water and wastewater treatment, oil and gas pipelines, and other situations where fluid must be moved in large volumes.
Ball Valves: Ball valves are versatile and can be used in a wide range of applications, including residential plumbing, industrial processes, and gas handling systems. They are particularly valued for their quick operation, durability, and tight sealing capabilities, making them suitable for applications requiring reliable on/off control and system isolation.

Advantages And Disadvantages

Gate Valves:
- Advantages: Full bore design resulting in minimal pressure drop; suitable for both slurries and viscous fluids; good for high temperature and pressure applications.
- Disadvantages: Prone to wear and leakage across the seats and gate; slower to operate; not suitable for throttling purposes due to potential seat and gate damage.
Ball Valves:
- Advantages: Quick and easy to operate with a quarter-turn; excellent sealing capabilities with low torque; durable with a long service life; suitable for throttling applications with proper design.
- Disadvantages: Potential for cavitation and flow turbulence at partial open conditions; the full bore models can be more expensive than reduced bore models.

Choosing Between Gate And Ball Valves

The choice between a gate valve and a ball valve often comes down to the specific needs of the application, including the type of fluid, required flow rate, operating pressure, and temperature, and whether precise flow control or simple on/off functionality is needed. Cost, ease of maintenance, and space constraints may also influence the decision.

In summary, gate valves are best suited for applications requiring unobstructed flow and minimal pressure drop, while ball valves offer superior sealing and control, making them ideal for a broad range of on/off and throttling applications.

GATE VALVE VS. GLOBE VALVE

What is the difference between a gate and a globe valve?

Gate valves and globe valves are two fundamental types of valves used in piping systems to control the flow of liquids, gases, and slurries. While they share some similarities, they have distinct features, operating principles, and applications that make them suitable for different scenarios.

Understanding the differences between these two valve types is crucial for selecting the right valve for a specific application.

Design And Operation

Gate Valve: Utilizes a flat gate or wedge that moves vertically to the flow direction to open or close the valve. When open, the gate fully retracts into the valve body, allowing for a full, unobstructed flow path. Gate valves are primarily used for on/off control and are not suitable for throttling due to the potential for gate and seat damage.
Globe Valve: Features a movable disk-type element and a stationary ring seat in a generally spherical body. The disk moves perpendicularly to the seat, allowing for precise flow control. Globe valves are characterized by their spherical body shape, with the internal baffle that splits the inside space into two chambers. They are used for on/off control as well as for throttling flow, offering better control over flow rates.

Applications

Gate Valves: Ideal for applications where a straight-line flow of fluid and minimum restriction is desired. Commonly used in water supply, natural gas pipelines, and in applications where the valve will remain either fully open or fully closed for long periods.
Globe Valves: Suited for applications requiring flow regulation and frequent operation. Their ability to adjust the flow with precision makes them popular in cooling systems, fuel oil systems, marine applications, and where pressure drop is not a significant concern.

Advantages And Disadvantages

Gate Valves:
- Advantages: Minimal pressure drop when fully open; suitable for both slurries and viscous fluids; provides a tight seal when closed.
- Disadvantages: Slow to open and close; not suitable for throttling; can be prone to gate and seat damage from vibration if partially opened.
Globe Valves:
- Advantages: Good for throttling and regulating flow; faster to open and close compared to gate valves; provides better sealing.
- Disadvantages: Higher pressure drop across the valve; not ideal for applications requiring full, unobstructed flow.

Choosing Between Gate And Globe Valves

Choosing between a gate valve and a globe valve often depends on the specific requirements of the system, including:

Purpose: Gate valves are preferred for on/off control where the flow rate is not adjusted frequently. Globe valves are chosen for applications where flow needs to be regulated or adjusted regularly.
Flow Characteristics: If minimal pressure drop and full flow are required, gate valves are more suitable. For precise flow control, even at lower flow rates, globe valves are preferred.
Space and Orientation: Globe valves, due to their design, may require more space in a piping system and are sensitive to flow direction. Gate valves are less restrictive in terms of space and flow direction.

In summary, the choice between gate and globe valves hinges on the need for either unobstructed flow and infrequent operation or the need for flow regulation and frequent adjustments. Both valves serve critical roles in controlling system flow, and their selection should align with the operational needs and constraints of the application.

GATE VALVE VS. CHECK VALVE

Gate valves and check valves are two distinct types of valves used across various industries for controlling fluid flow in piping systems. Each serves a different primary function and operates based on different principles.

Gate Valve

Design and Function: A gate valve features a movable gate or wedge that slides vertically to control the flow of fluid. It is operated manually, typically using a handwheel or an actuator for larger sizes. The primary function of a gate valve is to start or stop the flow, providing a clear and unobstructed path when fully open, and a tight seal when fully closed.

Applications: Gate valves are widely used in applications where a full, unrestricted flow of fluid is necessary. They are ideal for on/off control but are not suitable for throttling purposes, as partial opening can cause vibration and damage to the gate and seats. Common uses include water supply, oil and gas pipelines, and other systems where flow needs to be completely shut off or allowed freely.

Advantages:

Minimal pressure drop when fully open.
Suitable for both liquid and gas applications.
Provides a tight seal when closed.

Disadvantages:

Slow to open and close.
Not suitable for throttling.
Prone to wear and corrosion, which can affect sealing over time.

Check Valve

Design and Function: A check valve, also known as a non-return valve, allows fluid to flow in one direction and automatically prevents backflow when the fluid in the line reverses direction. It operates based on the flow pressure and does not require manual operation. The internal mechanism varies by design, including ball, swing, and lift check valves.

Applications: Check valves are essential in preventing backflow, protecting equipment, and ensuring the safety of the system. They are used in a wide variety of applications, including water and wastewater treatment, chemical processing, and residential plumbing systems. Any system where backflow could cause problems or where fluid needs to be maintained in a single direction benefits from the use of a check valve.

Advantages:

Prevents backflow automatically.
Can be used in a wide range of pressures and temperatures.
Available in various designs to suit specific flow characteristics.

Disadvantages:

Cannot be used to regulate or stop flow.
Some designs may cause a significant pressure drop.
Requires careful selection and installation to function correctly.

Key Differences Between Gate And Check Valves

Primary Function: Gate valves are used to start or stop the flow, while check valves are designed to prevent backflow and allow flow in only one direction.
Operation: Gate valves require manual or actuator operation to open or close, whereas check valves operate automatically based on flow conditions.
Application Use: Gate valves are chosen for system isolation or where full flow is necessary. Check valves are selected to prevent backflow and protect against reverse flow conditions.

Understanding these differences is crucial when designing or maintaining a piping system, ensuring that the right type of valve is used for its intended function, thereby optimizing system performance and safety.

GATE VALVE VS. BUTTERFLY VALVE

Gate valves and butterfly valves are widely utilized in various industrial and domestic piping systems for fluid control. Despite serving the purpose of regulating flow, they exhibit distinct differences in design, operation, maintenance, and application suitability.

Gate Valve

Design and Operation: A gate valve features a flat gate that moves up and down in a linear motion perpendicular to the direction of flow. The valve operates by a handwheel or an actuator, and it is primarily used for starting or stopping the flow, allowing for a full, unrestricted flow path when fully open.

Advantages:

Provides minimal pressure drop when fully open.
Suitable for both on/off and isolation applications.
Can handle thick fluids, as the gate can cut through viscous flow.

Disadvantages:

Slow to open and close due to the multiple turns required on the handwheel.
Not suitable for throttling applications, as partial opening can cause seat and gate damage.
Larger size compared to butterfly valves, requiring more space for installation and operation.

Butterfly Valve

Design and Operation: A butterfly valve consists of a disc that rotates around a central axis within the body of the valve, allowing for quick and efficient flow control. Operated by a handle, gear, or actuator, butterfly valves can be used for both on/off control and throttling.

Advantages:

Compact and lightweight design, requiring less space and support.
Quick to open and close, offering good control over the flow rate.
Generally more cost-effective than gate valves, especially in larger sizes.

Disadvantages:

The presence of the disc in the flow path can cause a pressure drop, even when fully open.
Not ideal for applications with particulate-laden fluids, as particles can accumulate around the disc and stem, potentially leading to wear or operational issues.
Sealing performance might not be as effective as gate valves for high-pressure applications.

Key Differences Between Gate And Butterfly Valves

Flow Control: Gate valves are best suited for on/off applications with minimal pressure drop, while butterfly valves offer superior functionality in throttling and quick operation scenarios.
Design and Space Requirements: Gate valves require more space due to their linear operation and larger size, making butterfly valves more suitable for compact or limited-space environments.
Cost and Maintenance: Butterfly valves are generally more cost-effective and easier to maintain due to their simpler design and fewer moving parts. Gate valves, on the other hand, may require more maintenance, especially in systems with solid or viscous fluids.

Application Suitability Of These Two Types Of Valves

Gate Valves: Preferred in applications where an unobstructed flow and tight shutoff are required, such as in water and wastewater treatment, oil and gas pipelines, and other high-pressure systems.
Butterfly Valves: Ideal for applications requiring flow regulation and where space and cost are concerns, including HVAC systems, pharmaceutical processing, and food and beverage industries.

Selecting between a gate valve and a butterfly valve depends on the specific requirements of the application, including flow control needs, system pressure, space constraints, and budget considerations. Each valve type offers unique advantages that make it suitable for particular scenarios, ensuring efficient and reliable fluid control in diverse settings.

GATE VALVE VS. PLUG VALVE

Gate valves and plug valves are both commonly used in piping systems for controlling the flow of fluids, but they have distinct differences in design, operation, and application suitability. Understanding these differences is essential for selecting the appropriate valve type for specific system requirements.

Gate Valve

Design and Operation: A gate valve controls flow by raising or lowering a metal gate, usually via a handwheel or an actuator. The gate moves perpendicularly to the fluid flow, offering minimal resistance when fully open, which makes it well-suited for applications requiring unobstructed flow or full isolation.

Advantages:

Provides a full-bore flow path when open, resulting in minimal pressure drop.
Suitable for both on/off services and isolation.
Can handle a wide range of fluids, temperatures, and pressures.

Disadvantages:

Not suitable for throttling applications, as partial openings can cause gate and seat damage.
Typically slower to operate due to the multiple turns required to open or close.
Larger and heavier than plug valves, requiring more space and support.

Plug Valve

Design and Operation: Plug valves control flow through a cylindrical or tapered plug with one or more hollow passageways. By rotating the plug 90 degrees, the flow can be allowed, blocked, or partially passed through the valve. Plug valves are known for their quick operation and are used for on/off control as well as throttling.

Advantages:

Quick to operate with a simple quarter-turn to open or close.
Compact and generally lighter than gate valves, making them suitable for tight spaces.
Good for applications requiring frequent operation and where flow regulation is needed.

Disadvantages:

The presence of the plug in the flow path can cause a pressure drop, even when fully open.
May not be suitable for high-pressure applications as sealing performance can be affected by high pressures.
Requires lubrication for smooth operation, which may not be ideal for some types of fluids.

Key Differences

Flow Control and Operation: Gate valves are best for on/off control where full flow is needed without obstruction. Plug valves offer rapid operation and are versatile for both on/off control and throttling.
Design and Space Requirements: Gate valves have a larger size and require more space, while plug valves are compact and suitable for limited-space applications.
Application Suitability: Gate valves are preferred in applications that demand minimal pressure drop and where valve operation is infrequent. Plug valves are favored for their quick operation, flow regulation capabilities, and when space constraints exist.

Application Suitability

Gate Valves: Ideal for larger-diameter pipelines, water treatment plants, and other settings where unobstructed flow and tight sealing are crucial.
Plug Valves: Commonly used in chemical and petrochemical industries, gas utilities, and where rapid or frequent operation is required.

In summary, the choice between a gate valve and a plug valve largely depends on the specific operational needs, including the desired control type (on/off or throttling), system pressure, space availability, and the frequency of valve operation. Each valve type offers distinct benefits and limitations, making them suitable for different applications.

GATE VALVE DIAGRAM

The gate valve diagram shows the standard assembly drawing of a gate valve.

Many design variations are possible, depending on the gate valve parts configuration:

Body material construction: forged or cast
Bonnet design and connection: can be standard BB or pressure seal (high-pressure gate valves), bolted/welded bonnet, etc.
Valve ends connection: gate valves are available with multiple valve ends designs (socket weld and threaded for forged gate valves and butt weld for cast body gate valves)
Wedge type (solid/flexible/split/parallel slide): see details below in this article
Stem type (rising/ non-rising): see details below
Manufacturing norm: API vs EN gate valves have slightly different designs
Type of valve operation: manual, gear, or pneumatic/hydraulic/electric actuation

Gate valve diagram showing the key parts of a gate valve for piping

GATE VALVE WEDGE TYPES

In gate valves, the wedge is the movable part that seals against seats to stop the flow or opens to allow flow. The design of the wedge is crucial for the valve’s performance, especially in terms of sealing capability, ease of operation, and durability. There are several types of wedges used in gate valves, each suited to different applications and operating conditions:

1. Solid Wedge

The solid wedge is the simplest and most robust type, made from a single piece of metal. Its simplicity makes it highly reliable and suitable for a wide range of conditions, including high-temperature and pressure environments. However, its rigidity means it may not always compensate for seat misalignments or changes in temperature that affect the valve body and seating surfaces.

2. Flexible Wedge

A flexible wedge is designed with a cut around its perimeter or a special shape that allows the wedge to flex as it seats. This design helps accommodate changes in valve body dimensions due to thermal expansion or contraction, improving the seal in varying temperature conditions. Flexible wedges are particularly useful in steam systems where temperature fluctuations are common. However, they can be less suitable for applications involving high vibration or thermal cycling, which may lead to fatigue cracks.

3. Split Wedge Or Parallel Disks

The split wedge, or parallel disk design, consists of two solid pieces that are hinged together or use a mechanism to keep them in alignment. This design allows the wedge to adjust to variations in the angle between the seats and the wedge surfaces, enhancing sealing effectiveness. Split wedges are advantageous in applications where thermal binding (sticking due to differential thermal expansion) is a concern.

4. Slab Gate

Slab gate valves use a flat gate that slides between two parallel seats, providing a tight seal. While not a wedge in the traditional sense, the slab gate functions similarly by blocking or allowing flow. This design is particularly favored in the oil and gas industry for pipeline valves because it provides a full-bore, low-friction path for the fluid, making it ideal for transporting viscous fluids like oil.

Wedge Selection Considerations

Choosing the appropriate wedge type depends on several factors:

Operating Conditions: Temperature fluctuations, pressure range, and the presence of vibrations can affect wedge selection.
Fluid Characteristics: Slurry services may require a specific wedge type to prevent particle trapping.
Sealing Requirements: Some applications demand tighter seals, influencing the choice of wedge design.

Understanding the different types of wedges in gate valves and their respective advantages and limitations is essential for selecting the right valve for a specific application, ensuring optimal performance and longevity.

The image below shows how the gate valve wedge opens and closes the flow of the fluid by application of a vertical movement (which can be manual or operated by an actuator).

The wedge is positioned between two parallel (or oblique) seats that are perpendicular to the flow. The fluid flows horizontally through gate valves and is not subject to pressure drops.

The image below shows the different types of wedges used in gate valves:

“solid wedge” (in this case, the wedge is manufactured with a solid piece of steel)
“flexible-wedge” (in this case the disc features cuts around its perimeter to enhance the ability of the valve to correct changes in the angle between the seats)
“split-wedge” (two pieces construction disc, to enforce self-alignment of the wedge on the seats)
“parallel-slide wedge“

GATE VALVE STEM TYPES

Gate valves control fluid flow by lifting a barrier (gate) out of the fluid path, and this operation is facilitated by the valve’s stem. The stem, which connects the actuator (e.g., handwheel, lever, or electric motor) to the gate, is a critical component in translating the actuator’s motion into the opening or closing of the valve. There are several types of stems used in gate valves, each with its specific design and operational characteristics:

1. Rising Stem (OS&Y – Outside Screw And Yoke)

The rising stem design features a stem that moves up and down along with the gate, providing a visual indication of the valve’s position (open or closed). In this configuration, the stem’s threads are external, located outside the valve body, and interact with the yoke, which is part of the actuator assembly. The rising stem design is advantageous for visual inspection and understanding the valve’s status, but it requires more vertical space for operation.

Advantages: Visible indication of valve position; reduced risk of thread contamination by the fluid.
Applications: Widely used in applications where valve status indication is important and where there is sufficient space for stem movement.

2. Non-Rising Stem (NRS)

In a non-rising stem design, the stem remains stationary in the vertical direction while the gate moves up and down. This is achieved by having the stem threads inside the valve body, engaging directly with the gate. Non-rising stem valves are compact and suitable for applications with limited vertical space.

Advantages: Requires less vertical space; suitable for underground installations or tight spaces.
Applications: Common in water, wastewater, and gas services where space constraints exist.

Rising and non rising stem of gate valves

3. Sliding Stem

Though not as common in gate valves, a sliding stem design can be found in some specialized gate valves where the stem slides in and out of the valve body without rotating. This design is similar in principle to the non-rising stem but is distinguished by the mechanism of stem movement.

4. Rotating Rising Stem

A rotating rising stem combines the visual position indication of a rising stem with a rotation mechanism. As the valve is opened or closed, the stem not only rises or lowers but also rotates. This rotation can help reduce the wear on the seating surfaces, extending the valve’s service life.

Advantages: Visual position indication and reduced seat wear due to rotation.
Applications: Useful in applications requiring durability and clear valve position indication.

Stem Selection Considerations

Choosing the right stem type for a gate valve involves several factors:

Space Availability: Non-rising stems are preferred in limited vertical space applications while rising stems are chosen when visual position indication is crucial and space permits.
Environment: External stem threads (rising stems) are less prone to contamination in clean environments, whereas internal threads (non-rising stems) are protected from the external environment but can be exposed to the process fluid.
Operation and Maintenance: Considerations include ease of operation, maintenance requirements, and the need for clear valve position indication.

Understanding the different types of stems and their operational characteristics is essential for selecting the appropriate gate valve for a specific application, ensuring optimal performance and longevity.

OS&Y VS. IS&Y DESIGN

It is very frequent to see the term “OS&Y” associated with gate valves.
This term means that when the handle of a gate valve is rotated to open or close the valve, it directly raises and lowers the disc by interacting with the stem of the valve.

In an “OS&Y gate valve”, the stem of the valve itself raises and lowers outside the body of the valve in a very visible way, while the handle remains in a fixed position.

When the stem raises, the disc inside the body of the valve rises from the seat letting the fluid flow through the valve (valve in open position).
Therefore with an OS&Y gate valve, the actual position of a valve (closed or open) is always evident to the operators.

Differently, the valve position is not immediately visible for “IS&Y gate valves” (inside screw and yoke), as the stem of the valve does not raise or lowers outside the valve when the handle is rotated.

GATE VALVE MATERIALS

BODY

The body of gate valves below 2 inches is generally made of forged steel (the most common body material grades are ASTM A105 for high-temperature service, ASTM A350 for low-temperature service, and, ASTM A182 F304/F316 for corrosive service).

The bodies of gate valves of bore sizes above 2 inches are, instead, made of cast steel (the main cast grades are ASTM A216 WCB for high-temperature service, ASTM A351 for low-temperature conditions, and ASTM A351 CF8 and CF8M – i.e. stainless steel 304 and 316 gate valves).

TRIM

The removable and replaceable parts of the valve are collectively defined as “trim” (for a gate valve: seat, disc, backseat, and, stem).
The API 600 specification foresees several standard trim combinations, as illustrated below

API TRIM #	BASE MATERIAL	MATERIAL FOR SEAT	MATERIAL FOR DISC	BACKSEAT MATERIAL	MATERIAL FOR STEM
1	410	410	410	410	410
2	304	304	304	304	304
3	F310	310	310	310	310
4	Hard 410	Hard 410	410	410	410
5	Hard faced	Stellite	Stellite	410	410
5A	Hard faced	Ni-Cr	Ni-Cr	410	410
6	410 and Cu-Ni	Cu-Ni	Cu-Ni	410	410
7	410 and Hard 410	Hard 410	Hard 410	410	410
8	410 and Hardfaced	Stellite	410	410	410
8A	410 and Hardfaced	Ni-Cr	410	410	410
9	Monel	Monel	Monel	Monel	Monel
10	316	316	316	316	316
11	Monel	Stellite	Monel	Monel	Monel
12	316 and Hardfaced	Stellite	316	316	316
13	Alloy 20	Alloy 20	Alloy 20	Alloy 20	Alloy 20
14	Alloy 20 and Hardfaced	Stellite	Alloy 20	Alloy 20	Alloy 20
15	304 and Hardfaced	Stellite	Stellite	304	304
16	316 and Hardfaced	Stellite	Stellite	316	316
17	347 and Hardfaced	Stellite	Stellite	347	347
18	Alloy 20 and Hardfaced	Stellite	Stellite	Alloy 20	Alloy 20

MATERIAL SELECTION

TRIM	RECOMMENDED SERVICE
13% Cr, Type 410 Stainless Steel	For oil and oil vapors and general services with heat treated seats and wedges.
13% Cr, Type 410 plus Hardfacing	Universal trim for general service requiring long service life up to 1100°F (593°C).*
Type 316 Stainless	For liquids and gases that are corrosive to 410 Stainless Steel, up to 1000°F (537°C).*
Monel	For corrosive service to 842°F (450°C) such as acids, alkalies, salt solutions, etc.
Alloy 20	For corrosive service such as hot acids -49°F to 608oF (-45°C to 320°C).
NACE	Specially treated 316 or 410 trim combined optionally with B7M Bolts and 2HM nuts to meet NACE MR-01-75 requirements.
Full Stellite	Full hard-faced trim, suitable for abrasive & severe services up to 1200°F (650°C).

GATE VALVE DIMENSIONS

The tables show the dimensions and weights of API 600 gate valves (bolted bonnet / rising stem)

CLASS 150

Dimensions in inches (millimeters)

Sizes	L	L1 (BW)	H (Open)	W
2″	7 (180)	8-1/2 (216)	14-1/2 (368)	8 (200)
2-1/2″	7-1/2 (190)	9-1/2 (241)	17 (432)	8 (200)
3″	8 (200)	11-1/8 (283)	18 (457)	8-7/8 (225)
4″	9 (230)	12 (305)	22 (559)	11 (279)
5″	10 (254)	15 (381)	26 (660)	12-3/4 (325)
6″	10-1/2 (266)	15-7/8 (403)	30 (762)	14 (356)
8″	11-1/2 (290)	16-1/2 (420)	38-1/2 (978)	14 (356)
10″	13 (330)	18 (457)	46 (1168)	18 (457)
12″	14 (356)	19 (502)	55-1/4 (1403)	20 (508)
14″	15 (381)	22 (559)	60 (1524)	21-1/2 (546)
16″	16 (407)	24 (610)	74-7/8 (1902)	24 (610)
18″	17 (432)	26 (660)	79 (2007)	27 (686)
20″	18 (457)	28 (711)	87-1/2 (2223)	28 (711)
24″	20 (508)	32 (813)	105 (2667)	31-1/2 (800)
30″	24 (610)	38 (965)	130 (3302)	43 (1092)
36″	28 (711)	44 (1118)	162 (4115)	51 (1295)
GEAR OPERATOR RECOMMENDED FOR SIZE 10″ AND ABOVE

CLASS 300

Dimensions in inches (millimeters)

SIZES	L/L1	H (OPEN)	W
2″	8-1/2 (216)	16 (407)	7-7/8 (200)
2-1/2″	9-1/2 (241)	17-3/8 (442)	7-7/8 (200)
3″	11-1/8 (283)	19-3/4 (501)	8-7/8 (225)
4″	12 (305)	23-3/8 (594)	9-7/8 (251)
5″	15 (381)	23-3/4 (603)	12-1/2 (318)
6″	15-7/8 (403)	32-1/8 (816)	14 (356)
8″	16-1/2 (420)	41 (1041)	15-3/4 (400)
10″	18 (457)	48-3/8 (1229)	17-3/4 (451)
12″	19-3/4 (501)	57 (1448)	20 (508)
14″	30 (762)	62-1/2 (1588)	22 (559)
16″	33 (838)	69 (1753)	25 (635)
18″	36 (914)	80-1/2 (2045)	28 (711)
20″	39 (991)	91 (2311)	35-1/2 (902)
24″	45 (1143)	120-1/2 (3061)	43 (1092)
GEAR OPERATOR RECOMMENDED FOR SIZE 8″ AND ABOVE

CLASS 600

Dimensions in inches (millimeters)

SIZES	L/L1	H (OPEN)	W
2″	11-1/2 (290)	16-1/2 (420)	7-7/8 (200)
2-1/2″	13 (330)	18 (457)	8-7/8 (225)
3″	14 (356)	20-1/8 (511)	9-7/8 (251)
4″	17 (432)	25 (635)	14 (356)
5″	20 (508)	30-1/2 (775)	15-3/4 (400)
6″	22 (559)	33-5/8 (854)	17-3/4 (451)
8″	26 (660)	42-3/8 (1076)	20 (508)
10″	31 (787)	49 (1245)	25 (635)
12″	33 (838)	68-1/2 (1740)	27 (686)
14″	35 (889)	69 (1753)	31-1/2 (800)
16″	39 (991)	74 (1880)	35-1/2 (902)
18″	43 (1092)	84-1/4 (2140)	43 (1092)
20″	47 (1194)	93-1/2 (2375)	51 (1295)
24″	55 (1397)	110 (2794)	51 (1295)
GEAR OPERATOR RECOMMENDED FOR SIZE 8″ AND ABOVE

CLASS 900

Dimensions in inches (millimeters)

SIZES	L/L1	H (OPEN)	W
2″	14-1/2 (368)	26 (660)	10-1/4 (260)
3″	15 (381)	26-3/8 (670)	11-1/2 (292)
4″	18 (457)	30 (762)	14 (356)
6″	24 (610)	40-3/4 (1035)	20 (508)
8″	29 (737)	51 (1295)	24 (610)
10″	33 (838)	61 (1549)	27 (686)
12″	38 (965)	69-1/2 (1765)	31-1/2 (800)
14″	40-1/2 (1029)	77 (1956)	35-1/2 (902)
16″	44-1/2 (1130)	82-3/4 (2102)	43 (1092)
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

CLASS 1500

Dimensions in inches (millimeters)

SIZES	L/L1	H (OPEN)	W
2″	14-1/2 (368)	21-1/2 (546)	11-1/2 (290)
3″	18-1/2 (470)	27-1/8 (689)	14 (356)
4″	21-1/2 (546)	31-1/2 (800)	20 (508)
6″	27-3/4 (705)	45 (1143)	24 (610)
8″	32-3/4 (832)	53-1/2 (1359)	27 (686)
10″	39 (991)	65 (1651)	35-1/2 (902)
12″	44-1/2 (1130)	74 (1880)	43 (1092)
14″	49-1/2 (1257)	83-1/2 (2121)	51 (1295)
16″	54-1/2 (1384)	88 (2235)	63 (1600)
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

CLASS 2500

Dimensions in inches (millimeters)

SIZES	L/L1	H (OPEN)	W
2″	17-3/4 (451)	24-7/8 (632)	12 (305)
3″	22-3/4 (578)	36 (914)	20 (508)
4″	26-1/2 (673)	41-1/2 (1054)	20 (508)
6″	36 (914)	57 (1448)	24 (610)
8″	40-1/4 (1022)	63-3/8 (1610)	24 (610)
GEAR OPERATOR RECOMMENDED FOR SIZE 6″ AND ABOVE

May 23, 2024/by stvvalve

industry valve news, News

Understand the Importance of the ASME B16.10 Specification

What is the face-to-face dimension of a flanged ball, globe, or gate valve? The ASME B16.10 chart answers this question, as it standardizes the distance between the inlet and the outlet of the most common flanged valves. The purpose of this ASME specification is to ensure the interchangeability of valves produced by different manufacturers.

WHAT IS VALVE FACE-TO-FACE DIMENSION?

The valve face-to-face dimension refers to the distance between the two end faces of a valve, which are the points where the valve connects to the piping system.

This measurement is crucial for ensuring that the valve fits properly within a given piping layout and for facilitating valve replacement or system upgrades. Manufacturers and industry standards, such as those provided by the American National Standards Institute (ANSI), American Petroleum Institute (API), and the Manufacturers Standardization Society (MSS), specify face-to-face dimensions for different types of valves (e.g., gate, globe, check, ball, and butterfly valves) and service conditions. Standardizing these dimensions helps in maintaining uniformity across valves produced by different manufacturers, allowing for easier interchangeability and system maintenance.

THE ASME B16.10 SPECIFICATION

ASME B16.10 is a widely recognized standard issued by the American Society of Mechanical Engineers (ASME) that specifies the face-to-face and end-to-end dimensions of flanged and butt-welded end steel valves. This standard is critical for ensuring the compatibility and interchangeability of valves within piping systems, facilitating easier installation, maintenance, and replacement.

The standard covers a variety of valve types, including gate, globe, plug, ball, check, and butterfly valves, and applies to a broad range of sizes and pressure classes.

By defining precise dimensions for each valve type, ASME B16.10 helps to standardize valve design across the industry, making it simpler for engineers and designers to select and specify valves for new installations or to find suitable replacements for existing systems.

Adherence to ASME B16.10 ensures that valves manufactured by different companies can be used interchangeably in a piping system without the need for modifications, provided they conform to the same type, size, and pressure class as specified in the standard.

This interoperability is crucial for maintaining the efficiency, safety, and reliability of fluid handling systems across various applications, including oil and gas, chemical processing, power generation, and water treatment.

ASME B16.10 SIGNIFICANCE FOR VALVES MANUFACTURERS

The ASME B16.10 standard plays a crucial role for valve manufacturers by providing a comprehensive guideline for the face-to-face and end-to-end dimensions of various types of valves, including gate, globe, check, ball, and butterfly valves. Adhering to this standard offers several significant benefits to manufacturers:

Ensures Interoperability: By defining standardized dimensions for valves, ASME B16.10 ensures that valves produced by different manufacturers can be used interchangeably within piping systems without the need for system modification. This interoperability is crucial for end-users looking to replace or upgrade valves without altering existing piping layouts.
Facilitates Design and Manufacturing Processes: ASME B16.10 provides a clear set of guidelines that manufacturers can follow during the design and manufacturing processes. This standardization helps streamline production, reduce design costs, and minimize the risk of errors that could lead to incompatibility with existing systems.
Enhances Market Competitiveness: Compliance with internationally recognized standards like ASME B16.10 demonstrates a manufacturer’s commitment to quality and reliability. This compliance can enhance a manufacturer’s reputation in the market, making their products more attractive to customers who prioritize standardization for ease of maintenance and system integrity.
Promotes Safety and Reliability: Following ASME B16.10 helps ensure that valves are designed to fit properly within a variety of systems, thereby reducing the likelihood of leaks or failures due to improper fit or installation. This contributes to the overall safety and reliability of fluid handling systems in critical applications across industries.
Simplifies Inventory and Distribution: For distributors and stockists, the standardization of valve dimensions means that a smaller inventory can serve a wider range of applications, reducing storage costs and simplifying logistics. This efficiency benefits manufacturers, distributors, and end-users alike.
Supports Regulatory Compliance: In many industries and regions, compliance with ASME standards is either a regulatory requirement or a key factor in project specifications. By adhering to ASME B16.10, valve manufacturers ensure that their products meet the necessary criteria for use in a wide range of projects, from industrial applications to infrastructure and beyond.

In summary, ASME B16.10 is essential for valve manufacturers as it promotes interoperability, streamlines production processes, enhances competitiveness, ensures safety and reliability, simplifies inventory management, and supports regulatory compliance. These benefits underscore the importance of this standard in the global valve manufacturing industry.

HOW TO SELECT VALVE FACE-TO-FACE

Selecting the appropriate valve face-to-face dimension according to ASME B16.10 involves a systematic approach, taking into consideration the type of valve, its application, and the specific requirements of the piping system. Here’s how you can go about it:

Identify the Valve Type
Start by identifying the type of valve you need for your application (e.g., gate, globe, ball, butterfly, check). Each valve type has different design characteristics and applications, influencing the required face-to-face dimension.
Determine the Valve Size and Class
Determine the size (diameter) of the valve required based on the flow rate and the size of the piping system. Also, identify the pressure class of the valve, which is based on the maximum pressure and temperature the valve needs to withstand. The size and class will impact the face-to-face dimensions.
Consult ASME B16.10
With the valve type, size, and class in mind, consult the ASME B16.10 standard. The standard provides tables with face-to-face and end-to-end dimensions for various types of valves across different sizes and pressure classes. Locate the appropriate table for your valve type and find the dimension that matches your valve’s size and class.
Consider System Requirements
Consider any specific requirements of your piping system that may influence the selection. For instance, if the valve is to replace an existing valve, ensure the selected dimension matches the available space and existing piping layout. For new installations, consider ease of maintenance, future replacements, and system expansion possibilities.
Check for Exceptions or Special Cases
Note that certain applications or systems may have exceptions or require special considerations that could affect the choice of valve face-to-face dimension. For example, specialized processes or extreme operating conditions may necessitate custom or non-standard dimensions. In such cases, consultation with valve manufacturers or engineering experts is advised.
Confirm Compatibility
Ensure that the selected valve and its face-to-face dimension are compatible with the flanges or end connections of the piping system. Compatibility is crucial for a leak-proof system and efficient operation.
Seek Manufacturer’s Data
Manufacturers often provide detailed catalogs or datasheets with their valves’ dimensions, including face-to-face lengths, which are compliant with ASME B16.10. Refer to these documents to confirm the selection and availability of the required valve.

Selecting the correct valve face-to-face dimension according to ASME B16.10 enhances the efficiency, safety, and reliability of your piping system. This process ensures that the valve will fit properly within the system, facilitating maintenance and future replacements while adhering to industry standards.

ASME B16.10 VALVE FACE-TO-FACE SIZE CHARTS (CLASS 150 TO 2500)

Valve face to face dimension ASME B16.10

VALVES CLASS 150

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

150#	Ball Long Pattern	Ball Short Pattern	Gate Solid Wedge and Double Disc	Gate Conduit	Plug Short Pattern	Plug Regular Pattern	Plug Venturi Pattern	Plug Round Port Full Bore	Globe Lift and Swing Check	Y-Globe and Y-Swing Check
1/2	108	108	108	–	–	–	–	–	108	140
3/4	117	117	117	–	–	–	–	–	117	152
1	127	127	127	–	140	–	–	176	127	165
1 1/4	140	140	140	–	–	–	–	–	140	184
1 1/2	165	165	165	–	165	–	–	222	165	203
2½	178	178	178	178	178	–	178	267	203	229
2½	190	190	190	190	190	–	–	298	216	279
3	203	203	203	203	203	–	203	343	241	318
4	229	229	229	229	229	305	229	432	292	368
5	–	–	254	–	254	381	–	–	356	–
6	394	267	267	267	267	394	394	–	406	470
8	457	292	292	292	292	457	457	–	495	597
10	533	330	330	330	330	533	533	–	622	673
12	610	356	356	356	356	610	610	–	698	775
14	686	381	381	381	–	686	686	–	787	–
16	762	406	406	406	–	762	762	–	914	–
18	864	–	432	432	–	864	864	–	978	–
20	914	–	457	457	–	914	914	–	978	–
22	–	–	–	508	–	–	–	–	1067	–
24	1067	–	508	508	–	1067	1067	–	1295	–
26	–	–	559	559	–	–	–	–	1295	–
28	–	–	610	610	–	–	–	–	1448	–
30	–	–	610	660	–	–	–	–	1524	–
32	–	–	–	711	–	–	–	–	–	–
34	–	–	–	762	1016	–	–	–	–	–
36	–	–	711	813	–	–	–	–	1956	–

VALVES CLASS 300

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

300#	Ball Long Pattern	Ball Short Pattern	Gate Solid Wedge and Double Disc and Conduit	Plug Short and Venturi Pattern	Plug Regular Pattern	Plug Round Port Full Bore	Globe and Lift Check	Swing Check
1/2	140	140	140	–	–	–	152	–
3/4	152	152	152	–	–	–	178	–
1	165	165	165	159	–	190	203	216
1 1/4	178	178	178	–	–	–	216	229
1 1/2	190	190	190	190	–	241	229	241
2½	216	216	216	216	–	282	267	267
2½	241	241	241	241	–	330	292	292
3	282	282	282	282	–	387	318	318
4	305	305	305	305	–	457	356	356
5	–	–	381	–	–	–	400	400
6	403	403	403	403	403	559	444	444
8	502	419	419	419	502	686	559	533
10	568	457	457	457	568	826	622	622
12	648	502	502	502	711	965	711	711
14	762	572	762	762	762	–	–	838
16	838	610	838	838	838	–	–	864
18	914	660	914	914	914	–	–	978
20	991	711	991	991	991	–	–	1016
22	1092	–	1092	1092	1092	–	–	1118
24	1143	813	1143	1143	1143	–	–	1346
26	1245	–	1245	1245	1245	–	–	1346
28	1346	–	1346	1346	1346	–	–	1499
30	1397	–	1397	1397	1397	–	–	1594
32	1524	–	1524	1524	1524	–	–	–
34	1626	–	1626	1626	1626	–	–	–
36	1727	–	1727	1727	1727	–	–	2083

VALVES CLASS 600

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

600#	Ball Long Pattern	Gate Solid Wedge and Double Disc and Conduit Long Pattern	Plug Regular and Venturi Pattern	Plug Round Port Full Bore	Globe Lift Check and Swing Check Long Pattern
1/2	165	165	–	–	165
3/4	190	190	–	–	190
1	216	216	216	254	216
1 1/4	229	229	229	–	229
1 1/2	241	241	241	318	241
2½	292	292	292	330	292
2½	330	330	330	381	330
3	356	356	356	444	356
4	432	432	432	508	432
5	–	508	–	–	508
6	559	559	559	660	559
8	660	660	660	794	660
10	787	787	787	940	787
12	838	838	838	1067	838
14	889	889	889	–	889
16	991	991	991	–	991
18	1092	1092	1092	–	1092
20	1194	1194	1194	–	1194
22	1295	1295	1295	–	1295
24	1397	1397	1397	–	1397
26	1448	1448	1448	–	1448
28	1549	1549	–	–	1600
30	1651	1651	1651	–	1651
32	1778	1778	1778	–	–
34	1930	1930	1930	–	–
36	2083	2083	2083	–	2083

VALVES CLASS 900

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

900 #	Gate Solid Wedge and Double Disc and Conduit Long Pattern	Plug Regular and Venturi Pattern	Plug Round Port Full Bore	Globe Lift Check and Swing Check Long Pattern	Ball Long Pattern
3/4	–	–	–	229	–
1	254	254	–	254	254
1¼	279	279	–	279	279
1½	305	305	356	305	305
2	368	368	381	368	368
2½	419	419	432	419	419
3	381	381	470	381	381
4	457	457	559	457	457
5	559	–	–	559	–
6	610	610	737	610	610
8	737	737	813	737	737
10	838	838	965	838	838
12	965	965	1118	965	965
14	1029	–	–	1029	1029
16	1130	1130	–	1130	1130
18	1219	–	–	1219	1219
20	1321	1321	–	1321	1321
22	–	–	–	–	–
24	1549	–	–	1549	1549

VALVES CLASS 1500

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

1500#	Gate Solid Wedge Double Disc and Conduit Long Pattern	Plug Regular and Venturi Pattern	Plug Round Port Full Bore	Globe Lift Check and Swing Check Short Pattern	Ball Long Pattern
1/2	–	–	–	216	–
3/4	–	–	–	229	–
1	254	254	–	254	–
1¼	279	279	–	279	–
1½	305	305	–	305	–
2	368	368	391	368	368
2½	419	419	454	419	419
3	470	470	524	470	470
4	546	546	625	546	546
5	673	–	–	673	–
6	705	705	787	705	705
8	832	832	889	832	832
10	991	991	1067	991	991
12	1130	1130	1219	1130	1130
14	1257	–	–	1257	1257
16	1384	1384	–	1384	1384
18	1537	–	–	1537	–
20	1664	–	–	1664	–
22	–	–	–	–	–
24	1943	–	–	1943	–

VALVES CLASS 2500

Note: dimensions in mm for flanged valves with RF face (ASME B16.10)

2500#	Gate Solid Wedge Double Disc and Conduit Long Pattern	Plug Regular Pattern	Globe Lift Check and Swing Check Long Pattern	Ball Long Pattern
1/2	264	–	264	–
3/4	273	–	273	–
1	308	308	308	–
1¼	349	–	349	–
1½	384	384	384	–
2	451	451	451	451
2½	508	508	508	508
3	578	578	578	578
4	673	673	673	673
5	794	794	794	–
6	914	914	914	914
8	1022	1022	1022	1022
10	1270	1270	1270	1270
12	1422	1422	1422	1422

The ASME B16.10 specification can be purchased here.

May 23, 2024/by stvvalve

industry valve news, News

ASME B16.34 specifies pressure and temperature ratings for valves

ASME B16.34 specifies pressure and temperature ratings for valves in different classes, ranging from 150 to 4500, guiding their safe use across varying operational conditions. It categorizes valve materials into groups based on their properties, such as carbon steel, stainless steel, and various alloys, to ensure compatibility with specific pressure and temperature conditions. This system facilitates the selection of appropriate valve materials for safety and efficiency in applications, considering factors like corrosion resistance and strength under pressure.

ASME B16.34 FOR VALVES

ASME B16.34 categorizes materials into several groups to standardize the application of valve materials across different temperature and pressure conditions. These groups help in selecting the appropriate material for valves based on operational requirements, ensuring compatibility with the fluid being handled and the environmental conditions of the application.

The material groups include various grades of carbon steel, stainless steel, alloy steel, and non-ferrous metals, each chosen for their specific properties like strength, corrosion resistance, and temperature tolerance.

ASME B16.34 mentions pipes, plates, and steel bars because it includes material specifications and grades for the manufacture of valve parts. These materials must meet specific standards to ensure that valves can safely operate under the pressure and temperature conditions for which they are rated. Including these materials helps ensure compatibility and safety across various applications in piping systems.

ASME B16.34 GROUP 1 MATERIALS: CARBON AND ALLOY

Material Group No.	Material Nominal Designation	Forging	Casting	Plate	Bar	Tubular
1.1	C C-SI C-MN-SIC-MN-SI-V	A105 A350 Gr. LF2A350 Gr. LF6 Cl.1	A216 Gr. WCB	A515 Gr. 70 A516 Gr. 70 A537 Gr. Cl.1	A675 Gr. 70 A105 A350 Gr. LF2 A696 Gr. C	A672 Gr. B70 A672 Gr. C70
1.2	C-SI 2 1/2NI 3 1/2NI C-MN-SIC-MN-SI-V	A350 Gr. LF3 A350 Gr. LF6 Cl.2	A352 Gr. LC2 A352 Gr. LC3 A216 Gr. WCC A352 Gr. LCC	A203 Gr. B A203 Gr. E	A350 Gr. LF3	A106 Gr. C
1.3	C C-SI 2 1/2NI 3 1/2NI C-MN-SI	–	A352 Gr. LCB	A515 Gr. 65 A203 Gr. A A203 Gr. D A516 Gr. 65	A675 Gr. 65	A672 Gr. B65 A672 Gr. C65
1.4	C C-SIC-MN-SI	A350 Gr. LF1	–	A515 Gr. 60A516 Gr. 60	A675 Gr. 60 A350 Gr. LF1 A696 Gr. B	A106 Gr. B A672 Gr. B60 A672 Gr. C60
1.5	C-1/2MO	A182 Gr. F1	A217 Gr. WC1 A352 Gr. LC1	A204 Gr. A A204 Gr. B	A182 Gr. F1	A691 Gr. CM-70
1.6	C-1/2MO1/2CR-1/2MO 1CR-1/2MO	–	–	A387 Gr. 2 Cl.1 A387 Gr. 2 Cl.2 A387 Gr. 12 Cl.1	–	A335 Gr. P1 A369 Gr. FP1 A691 Gr. 1/2CR
1.7	C-1/2MO 1/2CR-1/2MO NI-1/2CR-1/2MO 3/4NI-MO-3/4CR	A182 Gr. F2	A217 Gr. WC4 A217 Gr. WC5	A204 Gr. C	A182 Gr. F2	A691 Gr. MC-75
1.8	1CR-1/2MO 1 1/4CR-1/2MO-SI2 1/4CR-1MO	–	–	A387 Gr. 12 Cl.2 A387 Gr. 11 Cl.1A387 Gr. 22 Cl.1	–	A691 Gr. 1CR A335 Gr. P12 A369 Gr. FP12 A691 Gr. 1 1/4CR A335 Gr. P11 A369 Gr. FP11 A691 Gr. 2 1/4CR A335 Gr. P22 A369 Gr. FP22
1.9	1CR-1/2MO 1 1/4CR-1/2MO-SI 1 1/4CR-1/2MO	A182 Gr. F12 Cl.2 A182 Gr. F11 Cl.2	A217 Gr. WC6	A387 Gr. 11 Cl.2	A182 Gr. F12 Cl.2 A182 Gr. F11 Cl.2 A739 Gr. B11	–
1.10	2 1/4CR-1MO	A182 Gr. F22 Cl.3	A217 Gr. WC9	A387 Gr. 22 Cl.2	A182 Gr. F22 Cl.3 A739 Gr. B22	–
1.11	3CR-1MO MN-1/2MO MN-s1/2MO-1/2NI MN-1/2MO-3/4NI C-MN-SI	A182 Gr. F21	–	A387 Gr. 21 Cl.2 A302 Gr. A & B A302 Gr. C A302 Gr. D A537 Gr. CL2	A182 Gr. F21	–
1.12	5CR-1/2MO 5CR-1/2MO-SI	–	–	A387 Gr. 5 Cl.1 A387 Gr. 5 Cl.2	–	A691 Gr. 5CR A335 Gr. P5 A369 Gr. FP5 A335 Gr. P5b
1.13	5CR-1/2MO	A182 Gr. F5a A182 Gr. F5	A217 Gr. C5	–	A182 Gr. F5a A182 Gr. F5	–
1.14	9CR-1MO	A182 Gr. F9	A217 Gr. C12	–	A182 Gr. F9	–
1.15	9CR-1MO-V	A182 Gr. F51	A217 Gr. C12A	A387 Gr. 91 Cl.2	A182 Gr. F91	A335 Gr. P91

GROUP 1.1

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.1	C C-SI C-MN-SIC-MN-SI-V	A105 [1] [6] A350 Gr. LF2 [1] A350 Gr. LF6 Cl.1 [7]	A216 Gr. WCB [1]	A515 Gr. 70 [1] A516 Gr. 70 [1] [2] A537 Gr. Cl.1 [3]	A675 Gr. 70 [1] [4] [5] A105 [1] [6] A350 Gr. LF2 [1] A696 Gr. C	A672 Gr. B70 [1] A672 Gr. C70 [1]

[1] Upon prolonged exposure to temperatures above 800°F, the carbide phase of the steel may be converted to graphite. Permissible, but not recommended for prolonged use above 800°F.
[2] Not to be used over 850°F.
[3] Not to be used over 700°F.
[4] Leaded grades shall not be used where welded of in any application above 500°F.
[5] For service temperatures above 850°F, it is recommended that killed steels containing not less than 0.10% residual silicon be used.
[6] Only killed steel shall be used above 850°F.
[7] Not to be used over 500°F.

Maximum gage pressure (in psi) by temperature for Group 1.1 ASME B16.34 materials

Temp. °F	150#	300#	400#	600#	900#	1500#	2500#
-20 to 100	285	700	900	1480	2220	3705	6170
200	260	675	900	1350	2025	3375	5625
300	230	655	875	1315	1970	3280	5470
400	200	635	845	1270	1900	3170	5280
500	170	600	800	1200	1795	2995	4990
600	140	550	730	1095	1640	3735	4560
650	125	535	715	1075	1610	2685	4475
700	110	535	710	1005	1600	2665	4440
750	95	505	670	1010	1510	2520	4200
800	80	410	550	825	1235	2060	3430
850	65	270	355	535	805	1340	2230
900	50	170	230	345	515	860	1430
950	35	105	140	205	310	515	860
1000	20	50	70	105	155	260	430

GROUP 1.2

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.2	C-SI 2 1/2 NI 3 1/2 NI C-MN-SIC-MN-SI-V	A350 Gr. LF3 [2] A350 Gr. LF6 Cl.2 [4]	A352 Gr. LC2 [2] A352 Gr. LC3 [2] A216 Gr. WCC [1] A352 Gr. LCC [2]	A203 Gr. B [1] A203 Gr. E [1]	A350 Gr. LF3 [2]	A106 Gr. C [3]

Maximum gage pressure (in psi) by temperature for Group 1.2 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	290	750	1000	1500	2250	3750	6250
200	260	750	1000	1500	2250	3750	6250
300	230	730	970	1455	2185	3640	6070
400	200	705	940	1410	2115	3530	5880
500	170	665	885	1330	1995	3325	5540
600	140	605	805	1210	1815	3025	5040
650	125	590	785	1175	1765	2940	4905
700	110	570	755	1135	1705	2840	4730
750	95	505	670	1010	1510	2520	4200
800	80	410	550	825	1235	2060	3430
850	65	270	355	535	805	1340	2230
900	50	170	230	345	515	860	1430
950	35	105	140	205	310	515	860
1000	20	50	70	105	155	260	430

GROUP 1.3

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.3	C C-SI 2 1/2 NI 3 1/2 NI C-MN-SI	–	A352 Gr. LCB [5]	A515 Gr. 65 [1] A203 Gr. A [1] A203 Gr. D [1] A516 Gr. 65 [1] [2]	A675 Gr. 65 [1] [3] [4]	A672 Gr. B65 [1] A672 Gr. C65 [1]

[1] Upon prolonged exposure to temperatures above 800°F, the carbide phase of the steel may be converted to graphite. Permissible, but not recommended for prolonged use above 800°F.
[2] Not to be used over 850°F.
[3] Leaded grades shall not be used where welded in any application above 500°F.
[4] For service temperatures above 850°F, it is recommended that killed steel containing not less than 0.10% residual silicon be used.
[5] Not to be used over 650°F.

Maximum gage pressure (in psi) by temperature for Group 1.3 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	265	695	925	1390	2085	3470	5785
200	250	655	875	1315	1970	3280	5470
300	230	640	850	1275	1915	3190	5315
400	200	620	825	1235	1850	3085	5145
500	170	585	775	1165	1745	2910	4850
600	140	535	710	1065	1600	2665	4440
650	125	525	695	1045	1570	2615	4355
700	110	520	690	1035	1555	2590	4320
750	95	475	630	945	1420	2365	3945
800	80	390	520	780	1175	1955	3260
850	65	270	355	535	805	1340	2230
900	50	170	230	345	515	860	1430
950	35	105	140	205	310	515	860
1000	20	50	70	105	155	260	430

GROUP 1.4

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.4	C C-SIC-MN-SI	A350 Gr. LF1 [1]	–	A515 Gr. 60 [1] [2]A516 Gr. 60 [1] [2]	A675 Gr. 60 [1] [2] [3] A350 Gr. LF1 [1] A696 Gr. B	A106 Gr. B [1] A672 Gr. B60 [1] A672 Gr. C60 [1]

Maximum gage pressure (in psi) by temperature for Group 1.4 ASME B16.34 materials:

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	235	620	825	1235	1850	3085	1545
200	215	560	750	1125	1685	2810	4680
300	210	550	730	1095	1640	2735	4560
400	200	530	705	1060	1585	2645	4405
500	170	500	665	995	1495	2490	4150
600	140	455	610	915	1370	2285	3805
650	125	450	600	895	1345	2245	3740
700	110	450	600	895	1345	2245	3740
750	95	445	590	885	1325	2210	3685
800	80	370	495	740	1110	1850	3085
850	65	270	355	535	805	1340	2230
900	50	170	230	345	515	860	1430
950	35	105	140	205	310	515	860
1000	20	50	70	105	155	260	430

GROUP 1.5

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.5	C-1/2MO	A182 Gr. F1 [1]	A217 Gr. WC1 [1] [2] A352 Gr. LC1 [3]	A204 Gr. A [1] A204 Gr. B	A182 Gr. F1 [1]	A691 Gr. CM-70 [1]

[1] Upon prolonged exposure to temperatures above 875°F, the carbide phase of carbon-molybdenum steel may be converted to graphite. Permissible, but not recommended for prolonged use above 875°F.
[2] Use normalized and tempered material only.
[3] Not to be used over 650°F.

Maximum gage pressure (in psi) by temperature for Group 1.5 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	265	695	925	1390	2085	3470	5785
200	260	680	905	1360	2035	3395	5660
300	230	655	870	1305	1955	3260	5435
400	200	640	855	1280	1920	3200	5330
500	170	620	830	1245	1865	3105	5180
600	140	605	805	1210	1815	3025	5040
650	125	590	785	1175	1765	2940	4905
700	110	570	755	1135	1705	2840	4730
750	95	530	710	1065	1595	2660	4430
800	80	510	675	1015	1525	2540	4230
850	65	485	650	975	1460	2435	4060
900	50	450	600	900	1350	2245	3745
950	35	280	375	560	845	1405	2345
1000	20	165	220	330	495	825	1370

GROUP 1.6

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
1.6	C-1/2MO1/2CR-1/2MO 1CR-1/2MO	–	–	A387 Gr. 2 Cl.1 [3] A387 Gr. 2 Cl.2 [3] A387 Gr. 12 Cl.1 [2]	–	A335 Gr. P1 [1] [3] A369 Gr. FP1 [1] [3] A691 Gr. 1/2CR [3]

[1] Upon prolonged exposure to temperatures above 875°F, the carbide phase of carbon-molybdenum steel may be converted to graphite. Permissible, but not recommended for prolonged use above 875°F.
[2] Permissible, but not recommended for prolonged use above 1100°F.
[3] Not to be used over 1000°F.

Maximum gage pressure (in psi) by temperature for Group 1.6 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	225	590	790	1185	1775	2955	4930
200	225	590	790	1185	1775	2955	4930
300	225	590	790	1185	1775	2955	4930
400	200	570	765	1145	1775	2860	4765
500	170	550	735	1105	1655	2755	4595
600	140	535	710	1065	1600	2665	4440
650	125	525	695	1045	1570	2615	4355
700	110	510	685	1025	1535	2560	4270
750	95	475	630	945	1420	2365	3945
800	80	475	630	945	1420	2365	3945
850	65	460	615	920	1380	2295	3830
900	50	440	590	885	1325	2210	3685
950	35	315	420	630	945	1575	2630
1000	20	200	270	405	605	1010	1685
1050	20 [1]	155	205	310	465	770	1285
1100	20 [1]	95	130	190	290	480	800
1150	20 [1]	60	80	125	185	310	515
1200	15 [1]	40	50	75	115	190	315

ASME B16.34 GROUP 2 MATERIALS: STAINLESS STEEL

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
2.1	18CR-8NI	A182 Gr. F304 A182 Gr. F304H	A351 Gr. CF3 A351 Gr. CF8	A240 Gr. 304 A240 Gr. 340H	A182 Gr. F304 A182 Gr. F304H A479 Gr. 304 A479 Gr. 304H	A312 Gr. TP304 A312 Gr. TP304H A358 Gr. 304 A376 Gr. TP304 A376 Gr. TP304H A430 Gr. FP304 A430 Gr. FP304H
2.2	16CR-12NI-2MO 18CR-8NI18CR-13NI-3MO 16CR-12NI-2MO 19CR-10NI-3MO	A182 Gr. F316 A182 Gr. F316H	A351 Gr. CF3A A351 Gr. CF8AA351 Gr. CF3M A351 Gr. CF8M A351 Gr. CG8M	A240 Gr. 316 A240 Gr. 316HA240 Gr. 317	A182 Gr. F316 A182 Gr. F316H A479 Gr. 316 A479 Gr. 316H	A312 Gr. TP316 A312 Gr. TP316H A358 Gr. 316 A376 Gr. TP316 A376 Gr. TP316H A430 Gr. FP316 A430 Gr. FP316HA312 Gr. TP317
2.3	18CR-8NI 16CR-12NI-2MO	A182 Gr. F304LA182 Gr. F316L	–	A240 Gr. 304LA240 Gr. 316L	A182 Gr. F304L A479 Gr. 304L A182 Gr. F316L A479 Gr. 316L	A312 Gr. TP304L A312 Gr. TP316L
2.4	18CR-10NI-TI	A182 Gr. F321 A182 Gr. F321H	–	A240 Gr. 321 A240 Gr. 321H	A182 Gr. F321 A479 Gr. 321 A182 Gr. F321H A479 Gr. 321H	A312 Gr. TP321 A312 Gr. TP321H A358 Gr. 321 A376 Gr. TP321 A376 Gr. TP321H A430 Gr. FP321 A430 Gr. FP321H
2.5	18CR-10NI-CB	A182 Gr. F347 A182 Gr. F347H A182 Gr. F348 A182 Gr. F348H	A351 Gr. CF8C	A240 Gr. 347 A240 Gr. 347H A240 Gr. 348 A240 Gr. 348H	A182 Gr. F347 A182 Gr. F347H A182 Gr. F348 A182 Gr. F348H A479 Gr. 347A479 Gr. 347H A479 Gr. 348 A479 Gr. 348H	A312 Gr. TP347 A312 Gr. TP347H A358 Gr. TP347 A376 Gr. TP347 A376 Gr. TP347H A376 Gr. TP348 A430 Gr. FP347 A430 Gr. FP347H A312 Gr. TP348 A312 Gr. TP348H
2.6	25CR-12NI 23CR-12NI	–	A351 Gr. CH8 A351 Gr. CH20	A240 Gr. 309S A240 Gr. 309H	–	A312 Gr. TP309H A358 Gr. 309H
2.7	25CR-20NI	A182 Gr. F310H	A351 Gr. CK20	A240 Gr. 310S A240 Gr. 310H	A182 Gr. F310H A479 Gr. 310H A479 Gr. 310S	A312 Gr. TP310HA358 Gr. 310H
2.8	20CR-18NI-6MO 22CR-5NI-3MO-N 25CR-7NI-4MO-N24CR-10NI-4MO-V 25CR-5NI-2MO-2CU 25CR-7NI-3.5MO-W-CB 25CR-7NI-3.5MO-N-CB-W	A182 Gr. F44A182 Gr. F51 A182 Gr. F53 A182 Gr. F55	A351 Gr. CK3MCuN A351 Gr. CE8MN A351 Gr. CD4MCu A351 Gr. CD3MWCuN	A240 Gr. S31254A240 Gr. S31803 A240 Gr. S32750 A240 Gr. S32760	A479 Gr. S31254 A479 Gr. S31803 A479 Gr. S32750	A312 Gr. S31254 A358 Gr. S31254 A789 Gr. S31803 A790 Gr. S31803 A789 Gr. S32750 A790 Gr. S32750 A789 Gr. S32760 A790 Gr. S32760

GROUP 2.1

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
2.1	18CR-8NI	A182 Gr. F304 [1] A182 Gr. F304H	A351 Gr. CF3 [2] A351 Gr. CF8 [1]	A240 Gr. 304 [1] A240 Gr. 340H	A182 Gr. F304 [1] A182 Gr. F304H A479 Gr. 304 [1] A479 Gr. 304H	A312 Gr. TP304 [1] A312 Gr. TP304H A358 Gr. 304 [1] A376 Gr. TP304 [1] A376 Gr. TP304H A430 Gr. FP304 [1] A430 Gr. FP304H

[1] At temperatures over 1000°F, use only when the carbon content is 0.04% or higher.
[2] Not to be used over 800°F.

Maximum gage pressure (in psi) by temperature for Group 2.1 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	275	720	960	1440	2160	3600	6000
200	230	600	800	1200	1800	3000	5000
300	205	540	720	1080	1620	2700	4500
400	190	495	660	995	1490	2485	4140
500	170	465	620	930	1395	2330	3880
600	140	435	580	875	1310	2185	3640
650	125	430	575	860	1290	2150	3580
700	110	425	565	850	1275	2125	3540
750	95	415	555	830	1245	2075	3460
800	80	405	540	805	1210	2015	3360
850	65	395	530	790	1190	1980	3300
900	50	390	520	780	1165	1945	3240
950	35	380	510	765	1145	1910	3180
1000	20	320	430	640	965	1605	2675
1050	20 [1]	310	410	615	925	1545	2570
1100	20 [1]	255	345	515	770	1285	2145
1150	20 [1]	200	265	400	595	995	1655
1200	20 [1]	155	205	310	465	770	1285
1250	20 [1]	115	150	225	340	565	945
1300	20 [1]	85	115	170	255	430	715
1350	20 [1]	60	80	125	185	310	515
1400	20 [1]	50	65	95	145	240	400
1450	15 [1]	35	45	70	105	170	285
1500	10 [1]	25	35	55	80	135	230

[1] Use with buttweld valves only. The flanged end rating stops at 1000°F.

GROUP 2.2

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
2.2	16CR-12NI-2MO 18CR-8NI18CR-13NI-3MO 16CR-12NI-2MO 19CR-10NI-3MO	A182 Gr. F316 [1] A182 Gr. F316H	A351 Gr. CF3A [2] A351 Gr. CF8A [2]A351 Gr. CF3M [3] A351 Gr. CF8M [1] A351 Gr. CG8M [4]	A240 Gr. 316 [1] A240 Gr. 316HA240 Gr. 317 [1]	A182 Gr. F316 [1] A182 Gr. F316H A479 Gr. 316 [1] A479 Gr. 316H	A312 Gr. TP316 [1] A312 Gr. TP316H A358 Gr. 316 [1] A376 Gr. TP316 [1] A376 Gr. TP316H A430 Gr. FP316 [1] A430 Gr. FP316HA312 Gr. TP317 [1]

[1] At temperatures over 1000°F, use only when carbon content is 0.04% or higher.
[2] Not to be used over 650°F.
[3] Not to be used over 850°F.
[4] Not to be used over 1000°F.

Maximum gage pressure (in psi) by temperature for Group 2.2 ASME B16.34 materials

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	275	720	960	1440	2160	3600	6000
200	235	620	825	1240	1860	3095	5160
300	215	560	745	1120	1680	2795	4660
400	195	515	685	1025	1540	2570	4280
500	170	480	635	955	1435	2390	3980
600	140	450	600	900	1355	2255	3760
650	125	445	590	890	1330	2220	3700
700	110	430	580	870	1305	2170	3620
750	95	425	570	855	1280	2135	3560
800	80	420	565	845	1265	2110	3520
850	65	420	555	835	1255	2090	3480
900	50	415	555	830	1245	2075	3460
950	35	385	515	775	1160	1930	3220
1000	20	350	465	700	1050	1750	2915
1050	20 [1]	345	460	685	1030	1720	2865
1100	20 [1]	305	405	610	915	1525	2545
1150	20 [1]	235	315	475	710	1185	1970
1200	20 [1]	185	245	370	555	925	1545
1250	20 [1]	145	195	295	440	735	1230
1300	20 [1]	115	155	235	350	585	970
1350	20 [1]	95	130	190	290	480	800
1400	20 [1]	75	100	150	225	380	630
1450	20 [1]	60	80	115	175	290	485
1500	20 [1]	40	55	85	125	205	345

[1] Use with buttweld valves only. Flanged end rating stops at 1000°F.

ASME B16.34 GROUP 3 MATERIALS: NICKEL ALLOYS

MaterialGroup No.	Material NominalDesignation	Forging	Casting	Plate	Bar	Tubular
3.1	35NI-35FE-20CR-CB	B462 Gr. N08020	–	B463 Gr. N08020	B473 Gr. N08020	B464 Gr. N08020 B468 Gr. N08020
3.2	99NI	B160 Gr. N02200	–	B162 Gr. N02200	B160 Gr. N02200	B161 Gr. N02200 B163 Gr. N02200
3.3	99NI-Low C	B160 Gr. N02201	–	B162 Gr. N02201	B160 Gr. N02201	–
3.4	67NI-30CU67NI-30CU-S	B564 Gr. N04400B564 Gr. N04405	–	B127 Gr. N04400	B164 Gr. N04400B164 Gr. N04405	B165 Gr. N04400 B163 Gr. N04400
3.5	72NI-15CR-8FE	B564 Gr. N06600	–	B168 Gr. N06600	B166 Gr. N06600	B167 Gr. N06600 B163 Gr. N06600
3.6	33NI-42FE-21CR	B564 Gr. N08800	–	B409 Gr. N08800	B408 Gr. N08800	B163 Gr. N08800
3.7	65NI-28MO-2FE	B335 Gr. N10665	–	B333 Gr. N10665	B335 Gr. N10665	B662 Gr. N10665
3.8	54NI-16MO-15CR 60NI-22CR-9MO-3.5CB 62NI-28MO-5FE 70NI-16MO-7CR-5FE 61NI-16MO-16CR 42NI-21.5CR-3MO-2.3CU	B564 Gr. N10276 B564 Gr. N06625 B335 Gr. N10001 B573 Gr. N10003 B574 Gr. N06455 B425 Gr. N08825	–	B575 Gr. N10276 B443 Gr. N06625 B333 Gr. N10001 B434 Gr. N10003 B575 Gr. N06455 B424 Gr. N08825	B574 Gr. N10276 B446 Gr. N06625 B335 Gr. N10001 B573 Gr. N10003 B574 Gr. N06455 B425 Gr. N08825	B622 Gr. N10276B622 Gr. N10001B622 Gr. N06455 B423 Gr. N08825
3.9	47NI-22CR-9MO-18FE	B572 Gr. N06002	–	B435 Gr. N06002	B572 Gr. N06002	B622 Gr. N06002
3.10	25NI-47FE-21CR-5MO	B672 Gr. N08700	–	B599 Gr. N08700	B672 Gr. N08700	–
3.11	44FE-25NI-21CR-MO	B649 Gr. N08904	–	B625 Gr. N08904	B649 Gr. N08904	B677 Gr. N08904
3.12	26NI-43FE-22CR-5MO 47NI-22CR-20FE-7MO	B621 Gr. N08320 B581 Gr. N06985	–	B620 Gr. N08320 B582 Gr. N06985	B621 Gr. N08320 B581 Gr. N06985	B622 Gr. N08320 B622 Gr. N06985
3.13	49NI-25CR-18FE-6MO NI-FE-CR-MO-CU-Low C	B581 Gr. N06975 B564 Gr. N08031	–	B582 Gr. N06975 B625 Gr. N08031	B581 Gr. N06975 B649 Gr. N08031	B622 Gr. N06975 B622 Gr. N08031
3.14	47NI-22CR-19FE-6MO	B581 Gr. N06007	–	B582 Gr. N06007	B581 Gr. N06007	B622 Gr. N06007
3.15	33NI-2FE-21CR NI-MO NI-MO-CR	B564 Gr. N08810	B494 Gr. N-12MW B494 Gr. CW-12MW	B409 Gr. N08810	B408 Gr. N08810	B407 Gr. N08810
3.16	35NI-19CR-1 1/4SI	B511 Gr. N08330	–	B536 Gr. N08330	B511 Gr. N08330	B535 Gr. N08330
3.17	29NI-20.5CR-3.5CU-2.5MO	–	A351 Gr. CN-7M	–	–	–

MAX GAGE PRESSURE (In Psi) BY TEMPERATURE

Group 3.1

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	290	750	1000	1500	2250	3750	6250
200	260	720	960	1440	2160	3600	6000
300	230	715	950	1425	2140	3565	5940
400	200	675	900	1345	2020	3365	5610
500	170	655	875	1310	1965	3275	5460
600	140	605	805	1210	1815	3025	5040
650	125	590	785	1175	1765	2940	4905
700	110	570	755	1135	1705	2840	4730
750	95	530	710	1065	1595	2660	4430
800	80	510	675	1015	1525	2540	4230

Group 3.2

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	140	360	480	720	1080	1800	3000
200	140	360	480	720	1080	1800	3000
300	140	360	480	720	1080	1800	3000
400	140	360	480	720	1080	1800	3000
500	140	360	480	720	1080	1800	3000
600	140	360	480	720	1080	1800	3000

Group 3.3

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	90	240	320	480	720	1200	2000
200	85	230	305	455	685	1140	1900
300	85	225	300	445	670	1115	1860
400	85	215	290	430	650	1080	1800
500	85	215	290	430	650	1080	1800
600	85	215	290	430	650	1080	1800
650	85	215	290	430	650	1080	1800
700	85	215	290	430	650	1080	1800
750	80	210	280	420	635	1055	1760
800	80	205	270	410	610	1020	1700
850	65	205	270	410	610	1020	1700
900	50	140	185	280	415	695	1155
950	35	115	150	230	345	570	950
1000	20	95	125	185	280	465	770
1050	20 [1]	75	100	150	220	370	615
1100	20 [1]	60	80	125	185	310	515
1150	20 [1]	45	60	95	140	230	385
1200	15 [1]	35	50	75	110	185	310

[1] Use with buttweld valves only. The flanged end rating stops at 1000°F.

Group 3.4

Temp. °F	150	300	400	600	900	1500	2500
200	200	530	705	1055	1585	2640	4400
300	190	495	660	990	1485	2470	4120
400	185	480	635	955	1435	2390	3980
500	170	475	635	950	1435	2375	3960
600	140	475	635	950	1435	2375	3960
650	125	475	635	950	1435	2375	3960
700	110	475	635	950	1435	2375	3960
750	95	470	625	935	1405	2340	3900
800	80	460	610	915	1375	2290	3820
850	65	340	455	680	1020	1695	2830
900	50	245	330	495	740	1235	2055

Group 3.5

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	290	750	1000	1500	2250	3750	6250
200	260	750	1000	1500	2250	3750	6250
300	230	730	970	1455	2185	3640	6070
400	200	705	940	1410	2115	3530	5880
500	170	665	885	1330	1995	3325	5540
600	140	605	805	1210	1815	3025	5040
650	125	590	785	1175	1765	2940	4905
700	110	570	755	1135	1705	2840	4730
750	95	530	710	1065	1595	2660	4430
800	80	510	675	1015	1525	2540	4230
850	65	485	650	975	1460	2435	4060
900	50	450	600	900	1350	2245	3745
950	35	325	435	655	980	1635	2725
1000	20	215	290	430	650	1080	1800
1050	20 [1]	140	185	280	415	695	1155
1100	20 [1]	95	125	185	280	465	770
1150	20 [1]	70	90	135	205	340	565
1200	20 [1]	60	80	125	185	310	515

[1] Use with buttweld valves only. Flanged end rating stop at 1000°F.

Group 3.10

Temp. °F	150	300	400	600	900	1500	2500
-20 to 100	275	720	960	1440	2160	3600	6000
200	260	720	960	1440	2160	3600	6000
300	230	680	905	1360	2040	3400	5670
400	200	640	855	1280	1920	3205	5340
500	170	610	815	1225	1835	3060	5100
600	140	595	790	1190	1780	2970	4950
650	125	570	760	1140	1705	2845	4740

We recommend purchasing the ASME B16.34 specification from the ASME website or from the IHS store to get a complete understanding of this topic.

May 23, 2024/by stvvalve

industry valve news, News

Differences between Casting Vs. Forging

Steel items can be produced through either casting or forging processes. In steel casting, the metal is melted until it becomes liquid and is then poured into a mold to form the desired shape. Conversely, steel forging involves applying mechanical pressure to heated solid steel blocks (like ingots or billets), and permanently molding them into the required products.

STEEL FORGING VS. CASTING

BASIC DEFINITIONS

Steel casting and forging are two fundamental manufacturing processes used to form steel into desired products, each with distinct characteristics, advantages, and applications. Understanding the differences between these methods is crucial for choosing the most suitable approach for specific industrial needs.

Steel Casting

Steel casting involves melting steel into a liquid state and pouring it into a mold, where it solidifies into a specific shape. This process is advantageous for creating complex shapes and components that would be challenging to manufacture through other methods. Cast steel products can range from simple parts like gears and valves to intricate designs such as components for heavy machinery and automotive assemblies.

Steel casting finds applications in industries where complex shapes or specialized materials are required, including automotive, mining, aerospace, and construction.

Steel Forging

Forging involves heating solid steel blocks (ingots or billets) and then deforming them under high pressure or impact to achieve the desired shape. This process can be performed at various temperatures, leading to classifications such as cold forging, warm forging, and hot forging.

Steel forging is widely used in industries requiring high-strength components, such as automotive and aerospace for parts like gears, shafts, levers, and critical fasteners (including valves).

Both manufacturing processes require the application of high temperatures to steel raw materials (to liquefy or make it malleable) and the execution of CNC machining work at the end of the process to obtain the final product.

Final products may also undergo surface finish treatment, such as painting, powder coating, polishing, various types of coating (for example zinc plating) and wear protection/hardening (application of tungsten carbide overlay).

Last but not least, cast and forged parts may be assembled, welded, brazed, and hard-faced before being shipped as final products.

The products resulting from casting and forging processes have different properties in terms of surface porosity (generally better for forged vs. cast products), grain structure (finer for forged products), tensile strength (generally superior for forged products), and fatigue resistance.

These alternative manufacturing processes are therefore used (and suited for) different circumstances and applications.

CHOOSING BETWEEN CAST & FORGED PRODUCTS

The decision to use casting or forging depends on several factors:

Design Complexity: Casting is preferred for more complex shapes while forging is ideal for simpler, high-strength parts.
Material Properties: If the application requires specific alloy properties, casting may offer more flexibility. For applications where material strength and integrity are paramount, forging is often the better choice.
Production Volume: Forging can be more cost effective for large production runs of simpler shapes, whereas casting can be more economical for small to medium batches, especially of complex parts.
Cost Considerations: Initial setup costs for casting molds can be high, but per-unit costs decrease with volume. Forging requires significant investment in tooling and machinery, especially for high-volume production.

The casting process is generally preferred for:

parts and components that would be too complex or expensive to manufacture by steel forging (for example: large valve bodies);
parts that have internal cavities;
large-sized parts (there are virtually no size limits in terms of the weight of the parts that can be produced with the casting process);
parts in special alloys (some specific alloys are more difficult to forge than cast, for example, those with a high content of Nickel and Moly, which have considerable resistance to mechanical forces);
parts requiring mass production and small lots.

The forging process is preferred for:

parts requiring extremely high strength, toughness, and resistance (indeed, during the forging process the steel grain structure gets modified to conform to the shape of the final product – with high uniformity of composition and metallurgical recrystallization);
parts that have to withstand stronger impacts and mechanical forces;
parts where porosity, the risk of a gas void, pockets, and the possible formation of cavities (even micro-granular) are not acceptable;
production of mechanically strong parts without using expensive alloys;
parts that require high wear resistance;
parts subject to high loads and stress;
high-end applications when the integrity and the quality of the part are the main objectives in the production process, rather than time and cost.

The evolution of casting technologies has reduced the gap between the physical properties of cast vs. forged products making modern cast products very competitive in terms of quality, strength, and wear resistance: however, in many fields, steel forging remains, still, the preferred manufacturing option (example: small sized valves, i.e. forged valves, or high-pressure valves).

Read about forging steel on Wikipedia.

FIELDS OF APPLICATION

Steel casting and forging are used to produce products and parts for a multitude of sectors, including but not limited to:

petrochemical plants (for example forged valves, forged fittings, flanges, etc)
power generation and waste processing
mining and mineral processing
agriculture and livestock handling
water treatment
aeronautics
automobile industry (pulleys and gear wheels)
materials handling
brickworks
asphalt plants
stormwater parts
rendering plants
railways

STEEL CASTING

DEFINITION

Steel casting is a manufacturing process that involves melting steel until it becomes liquid, then pouring the molten steel into a mold where it solidifies into the desired shape. This method allows for the production of parts with complex geometries and detailed features that might be challenging to achieve through other manufacturing processes.

The molds used can be made from a variety of materials, including sand, metal, or ceramics, depending on the precision, surface finish, and reuse requirements of the casting. Steel castings are utilized across a broad range of industries, including automotive, aerospace, construction, and energy, due to their versatility in shape and size, and the ability to tailor the material properties through the selection of specific steel alloys and post-casting treatments such as heat treatment.

This process is particularly valuable for producing components that require high strength, durability, and resistance to wear and corrosion.

STEEL CASTING PROCESS

The steel casting manufacturing process involves several key steps that transform steel into precisely shaped components. This process is known for its ability to produce complex shapes and sizes, offering flexibility in design and material properties.

Here’s an overview of the main stages in the steel casting manufacturing process (in general terms, variations may exist based on the specific type of casting process adopted):

1. Pattern Making

The first step is creating a pattern that represents the shape of the final casting. Patterns can be made from various materials such as wood, plastic, or metal, depending on the complexity of the design and the casting quantity. The pattern is a replica of the final part but slightly larger to account for the shrinkage of the metal during cooling.

2. Mold Making

Using the pattern, a mold is made by packing a molding material (often sand mixed with binders) around the pattern in a molding box. When the pattern is removed, it leaves a cavity in the shape of the part to be cast. For complex parts, the mold consists of two halves (cope and drag) that are assembled before pouring. Cores may be used to form internal cavities within the casting.

3. Melting and Pouring

Steel is melted in a furnace at temperatures exceeding 1600°C (2900°F). The composition of the steel alloy is carefully controlled to meet the specific properties required for the casting. Once the steel is melted and any required alloying elements are added, the molten steel is poured into the prepared mold. The pouring process must be carefully controlled to ensure the mold is filled completely and to avoid defects.

4. Solidification and Cooling

After pouring, the steel begins to cool and solidify within the mold. Cooling rates can affect the microstructure and properties of the cast part. In some cases, directional solidification is used to control the way the metal cools, minimizing internal stresses and defects.

5. Mold Removal

Once the steel has fully solidified and cooled, the mold material is broken away to reveal the cast part. Sand molds are typically destroyed to remove the casting, while metal molds (used in permanent mold casting processes) are opened and reused.

6. Cleaning and Finishing

The casting is cleaned to remove any residual mold material and inspected for defects. Excess material from the pouring process, such as gates and runners, is removed. The casting may undergo various finishing processes, including grinding, machining, and heat treatment, to achieve the desired surface finish and mechanical properties.

7. Inspection and Quality Control

The final step involves inspecting the casting for defects and ensuring it meets the specified dimensions and material properties. Non-destructive testing methods such as X-ray or ultrasonic testing may be used to detect internal defects.

ADVANTAGES/DISADVANTAGES OF CAST STEEL

Advantages

Cast steel offers a unique set of advantages that make it a preferred choice for a wide range of applications across various industries. These benefits stem from the versatility of the casting process as well as the intrinsic properties of steel. Here are some of the key advantages of cast steel:

1. Design Flexibility

Cast steel allows for the production of complex shapes and intricate designs that are difficult or impossible to achieve with other manufacturing processes. This flexibility enables designers and engineers to create components with optimized geometries for specific applications, incorporating features like internal cavities, contours, and complex external shapes without the need for assembly or welding of multiple parts.

2. Material Properties

Steel casting can utilize a wide range of steel alloys, offering the ability to tailor the material properties to specific application requirements. This includes adjusting the alloy composition to enhance strength, ductility, wear resistance, impact resistance, and corrosion resistance. Additionally, post-casting heat treatments can further modify the mechanical properties, providing additional customization options to meet the demands of the application.

3. Large Component Production

The steel casting process is well-suited for producing large components that would be challenging or cost-prohibitive to manufacture through forging or machining from a solid block of steel. This capability is particularly valuable in industries such as mining, construction, maritime, and energy, where large, durable components are essential.

4. Cost-Effectiveness

For small to medium production volumes, casting can be more cost-effective than other manufacturing methods, especially for complex shapes that would require extensive machining or assembly of multiple parts. The ability to produce near-net-shape components reduces the need for additional processing and material waste, further contributing to cost savings.

5. Surface Finish and Detail

Cast steel can achieve a good surface finish and a high level of detail directly from the mold, reducing the need for additional finishing processes. This is beneficial for parts that require precise dimensions or aesthetic considerations.

6. Reliability

Steel castings undergo stringent quality control and testing procedures to ensure they meet the required specifications and standards. Non-destructive testing (NDT) techniques, such as x-ray, ultrasonic, and magnetic particle inspection, help detect any internal or surface defects, ensuring the reliability and performance of the cast component in its intended application.

7. Speed to Market

The casting process can be relatively quick from design to production, especially for prototypes or limited production runs. This speed can significantly reduce the time to market for new products or components, providing a competitive advantage.

In conclusion, the combination of design flexibility, customizable material properties, and cost-effectiveness makes cast steel a versatile and valuable option for a wide range of industrial applications. From heavy machinery and automotive components to artistic and architectural elements, the advantages of cast steel enable engineers and designers to meet complex challenges and deliver innovative solutions.

Disadvantages

The manufacturing and utilization of cast steel components offer distinct advantages but also come with certain disadvantages. Understanding these can help in making informed decisions about when and how to use cast steel in various applications:

1. Cost

Initial Costs: The production of cast steel components can involve high initial costs due to the need for specialized molds, which can be expensive to manufacture, especially for intricate designs or low production volumes. This can make cast steel less economical for small batches.
Material Costs: Steel, especially alloyed varieties used in casting for enhanced properties, can be more expensive than other metals, adding to the overall cost of the casting process.

2. Surface Finish and Tolerances

Surface Finish: Cast steel might have a rougher surface finish compared to other manufacturing processes like forging or machining. This can necessitate additional finishing processes, increasing production time and costs.
Dimensional Tolerances: Achieving tight dimensional tolerances can be more challenging with cast steel, especially for complex shapes or large components. This might require further machining or processing to meet precise specifications.

3. Porosity and Defects

Porosity: The casting process can introduce porosity (tiny holes or voids) in the steel, which can affect the mechanical strength and integrity of the part. Porosity is particularly concerning in applications where pressure integrity or structural strength is critical.
Defects: Castings are susceptible to various defects such as shrinkage cavities, cold shuts, and inclusions. These defects not only compromise the structural integrity and mechanical properties of the part but also require rigorous inspection and quality control measures to detect and mitigate.

4. Material Limitations

Alloy Restrictions: While casting allows for the use of a wide range of alloys, some compositions might not be suitable for casting due to their melting characteristics or reactions with mold materials. This can limit the choice of materials for specific applications.
Size and Weight Limitations: There are practical limits to the size and weight of cast steel components, dictated by the capacity of foundry equipment and the challenges of managing heat dissipation and material properties uniformly across large castings.

5. Environmental Considerations

Energy Consumption: The melting and casting of steel require significant amounts of energy, contributing to the environmental footprint of cast steel products.
Waste Production: The process can generate waste, including used molds and cores, excess metal from gates and risers, and defective castings, which need to be managed and recycled when possible.

TYPES OF STEEL CASTING PROCESSES

Steel casting processes can be categorized based on the type of mold used, the method of mold filling, and the handling of the molten steel. Each process has its unique advantages and is suited to specific applications. Here’s an overview of the primary types of steel casting processes:

Sand Casting

Sand casting is the oldest casting method and consists of pouring liquid metal into binders that resist the molten metal (such as clay bonded/green sand hard bonded/resin, thermosetting resin sand, and shell).

Description: This is the most common and versatile method, using sand molds to create steel parts. The sand can be shaped into complex forms, making it suitable for a wide range of components.
Applications: Used for large parts and small to medium production runs, including automotive frames, heavy machinery components, and decorative pieces.

Investment Casting (Lost Wax Casting)

This term refers to precision molding executed by injecting the liquid metal into a metal die and a ceramic coating. The mold material can be hard wax, lost wax, lost foam, and similar. Investment casting is the preferred method for manufacturing parts with a high number of details, and small parts that cannot afford the costs of traditional sand casting.

Description: A precision casting process where a wax model is coated with refractory material to create a mold. After the wax is melted out, molten steel is poured into the cavity. This method provides excellent surface finish and dimensional accuracy.
Applications: Ideal for small, complex components with tight tolerances, such as turbine blades, medical equipment, and firearm components.

Centrifugal Casting

Description: In this process, molten steel is poured into a rotating mold, creating parts with cylindrical shapes. The centrifugal force pushes the molten steel against the mold walls, producing a dense and uniform casting.
Applications: Used for components requiring high material integrity, such as pipes, cylinders, and rings.

Continuous Casting

Description: A highly efficient process where molten steel is solidified in a continuous strand through a mold. The solidified steel is then cut into desired lengths. This method significantly reduces the need for further processing.
Applications: Primarily used for producing basic shapes like billets, blooms, and slabs, which are further processed into various steel products.

Shell Molding

Description: Similar to sand casting, but uses a resin-coated sand that bonds to form a shell around the pattern. This method offers a better surface finish and more precise dimensions than traditional sand casting.
Applications: Suitable for medium to high-volume production of small to medium-sized parts, such as valve components and gear housings.

Vacuum Casting

Description: A process where molten steel is poured into a mold under a vacuum. This reduces the occurrence of defects and improves the quality of the casting by minimizing turbulence and gas entrapment.
Applications: Used for components that require high integrity and are free of pores and voids, such as in the aerospace and power generation industries.

Die Casting

Note: While die casting is predominantly used with non-ferrous metals due to the high melting point of steel, there are specialized high-pressure die-casting processes capable of handling steel alloys.
Applications: Suitable for high-volume production of small, precise components that require a good surface finish.

Each steel casting process has its ideal applications based on the required part size, complexity, production volume, and material properties. Selecting the appropriate casting method is crucial for achieving the desired part performance and cost-efficiency. Sand casting is used for large parts, investment casting for small parts up to 100 kilograms and 1,5 meters of max. length.

STEEL FORGING

DEFINITION

Steel forging is a manufacturing process involving the shaping of metal using localized compressive forces. In steel forging, steel is heated to a high temperature, making it pliable, and then it is hammered, pressed, or rolled into a desired shape.

This process can be performed at various temperatures, leading to different classifications such as hot forging, warm forging, and cold forging, each offering distinct advantages in terms of the material’s ductility and finished properties.

Steel forging appeared in China in the ancient ages to produce various types of metal products.

While the methods and equipment for creating forged components have evolved since those old days—from traditional anvils, hammers, and manual labor to modern automated machinery like hydraulic presses—the fundamental process of steel forging remains consistent. It involves heating solid steel blocks and then shaping them into finished products through the application of mechanical forces, such as hammering.

FORGING PROCESS

The steel forging process is a critical manufacturing technique used to shape metal into desired forms through the application of force and heat. It involves several key steps that transform a piece of steel into a strong, durable component with specific properties. Here’s a detailed look at the steel forging process:

1. Material Selection

The process begins with selecting the appropriate type of steel for the intended application. The choice depends on the required mechanical properties, such as strength, ductility, and resistance to wear and corrosion. Commonly used steel grades in forging include carbon steel, alloy steel, stainless steel, and tool steel.

2. Heating

The selected steel is heated to a high temperature, typically between 950°C and 1250°C (1742°F and 2282°F), although the exact temperature depends on the type of steel and the specific forging process being used. Heating the steel makes it more pliable and easier to deform. This step is crucial for hot forging, while warm forging and cold forging require different temperature ranges.

3. Forging

Once the steel is at the appropriate temperature, it is forged using one of several techniques:

Hammer Forging (Drop Forging): The steel is placed on an anvil and struck repeatedly with a hammer, either manually or mechanically. This method is effective for creating a wide variety of shapes with good precision.
Press Forging: The steel is compressed between two dies using a hydraulic or mechanical press, applying pressure gradually rather than through successive impacts. Press forging allows for better control over the deformation process and is suitable for large-scale production.
Rolled Forging: The heated steel is passed through two rolls that decrease its thickness and increase its length. Rolled forging is commonly used for producing long, cylindrical shapes like shafts.

4. Shaping

During the forging process, the steel’s internal grain structure deforms to conform to the shape of the part. This alignment enhances the mechanical properties of the steel, such as strength and toughness. The steel can be shaped into nearly any form, from simple flat sheets to complex geometrical components.

5. Trimming

Excess material, known as flash, is often produced during the forging process, especially in die forging. This excess material is trimmed off while the steel is still hot or after it cools down, depending on the specific process and material properties required.

6. Heat Treatment

After forging, the steel components may undergo various heat treatment processes such as annealing, normalizing, quenching, and tempering. These treatments are used to adjust the steel’s properties, such as increasing hardness, improving ductility, or relieving internal stresses induced during forging.

7. Finishing

The last step involves finishing the forged steel component to achieve the desired surface finish and dimensional accuracy. This may include machining, grinding, and polishing, depending on the application requirements.

8. Inspection and Testing

Finally, the forged steel components are inspected and tested to ensure they meet the required specifications and quality standards. This can involve dimensional checks, visual inspection, and various non-destructive testing methods, such as ultrasonic or magnetic particle inspection.

Upon completion of the process, the resulting products possess remarkable strength, impact toughness, and resistance to wear. This is attributed to the metallurgical changes, specifically recrystallization and grain refinement, that occur due to the thermal and mechanical treatments applied during the process.

The video below shows how steel forging works:

ADVANTAGES/DISADVANTAGES OF FORGED STEEL

Forged steel, known for its strength and reliability, is a preferred material for many industrial applications. However, like any manufacturing process, steel forging has its set of advantages and disadvantages. Understanding these can help in making informed decisions about its use in specific applications.

Advantages Of Forged Steel

1. Superior Strength and Toughness

Forging refines the grain structure of the steel, aligning it with the shape of the product. This enhances the mechanical properties of the steel, making forged parts stronger and more resistant to impact and fatigue compared to cast or machined parts.

2. Improved Reliability

The forging process produces parts with consistent material properties and without internal voids, cracks, or other defects that could weaken the part. This uniformity ensures high reliability and performance, especially in critical applications.

3. Reduced Material Waste

Modern forging techniques are highly efficient, often resulting in less material waste compared to other manufacturing processes like casting or machining. This efficiency can lead to cost savings, especially in high-volume production.

4. Versatility in Materials

Steel forging can be performed with a wide range of alloys, allowing for the production of parts with specific properties tailored to the application, including high-temperature resistance, corrosion resistance, and wear resistance.

5. Cost-Effective for Large Production Runs

Although the initial setup and tooling costs can be high, forging can be more cost-effective than other processes for large production runs due to its material efficiency and the reduced need for secondary processing.

Disadvantages Of Forged Steel

1. Higher Initial Costs

The initial costs for setup and tooling in forging can be significant, especially for complex shapes. This can make forging less economical for small production runs compared to other manufacturing processes.

2. Limitations on Shape Complexity

While forging can produce a wide range of shapes, extremely complex or intricate designs may be challenging to achieve through forging alone and might require additional machining or processing.

3. Size Limitations

The size of forgings is generally limited by the capacity of the forging equipment. Very large components might be difficult or impractical to forge and may require alternative manufacturing methods.

4. Need for Secondary Processing

Depending on the application’s requirements, forged parts may require secondary processes such as machining, heat treatment, or surface finishing to achieve the desired dimensions, properties, or surface quality.

5. Energy Intensive

The forging process, particularly hot forging, requires significant amounts of energy to heat the metal, which can impact the overall environmental footprint of the manufacturing process

TYPES OF STEEL FORGING PROCESSES

Steel forging processes vary in technique and application, each suited to different manufacturing requirements and objectives. These processes are categorized mainly based on the temperature at which the steel is forged (cold, warm, or hot forging) and the method of applying force (hammer or press forging). Here’s a closer look at the primary types of steel forging processes:

1. Hot Forging

Description: Performed at temperatures typically between 950°C and 1250°C (1742°F to 2282°F), hot forging allows the steel to be shaped easily, as the high temperature increases its plasticity and reduces resistance to deformation.
Advantages: Enables the forging of complex shapes with less force and energy; reduces strain hardening during the process.
Applications: Used for parts that require high strength and toughness, such as automotive components, construction equipment, and machinery parts.

2. Cold Forging

Description: This process is carried out at or near room temperature, offering a cleaner finish and stronger products due to strain hardening.
Advantages: Produces parts with excellent surface finish and dimensional accuracy; increases the strength of the steel through work hardening.
Applications: Suitable for smaller products with simpler shapes, like fasteners, screws, and bolts, where high precision and strength are required.

3. Warm Forging

Description: Warm forging is conducted at temperatures ranging from 650°C to 950°C (1202°F to 1742°F), serving as a middle ground between hot and cold forging.
Advantages: Balances the benefits of hot and cold forging, allowing for reduced force compared to cold forging and better dimensional accuracy than hot forging.
Applications: Often used for medium-complexity parts where a balance between strength, precision, and cost is needed.

4. Open-Die Forging

Description: In open-die forging, the steel is worked between two flat or simply contoured dies that do not enclose the workpiece, allowing the material to flow outward as it is forged.
Advantages: Highly versatile, capable of producing very large parts, and allows for the adjustment of the workpiece during forging.
Applications: Ideal for large, simple shapes such as shafts, bars, beams, and plates.

Open die forging involves shaping metal by pressing or hammering it between two dies that don’t entirely enclose the material. The piece of metal is worked upon through successive movements of the dies, which apply force to mold the metal into the desired shape. This technique is demonstrated in the action showcased in the video below:

5. Closed-Die Forging (Impression-Die Forging)

Description: Steel is compressed between two or more dies that contain a precut profile of the desired part, resulting in a more precise and complex shape.
Advantages: Produces parts with close tolerances and minimal waste; suitable for high-volume production.
Applications: Widely used for automotive, aerospace, and industrial components that require detailed features and high strength.

Closed-die forging is a process where the dies close in on the workpiece, either completely enclosing it or partially. The process begins by placing a piece of heated raw material, roughly shaped or sized to match the final product, into the lower die. This process is demonstrated in the following video:

6. Seamless Rolled Ring Forging

Description: This process involves piercing a hole in a thick, round piece of metal to create a donut shape, which is then rolled and stretched to produce a seamless ring.
Advantages: Efficiently produces rings with excellent structural integrity and homogeneous characteristics.
Applications: Commonly used for bearings, flanges, gear rings, and wind turbine components.

Difference Between Open-Die & Close-Die Forging

Open-die and closed-die forging are two fundamental processes used in metalworking to shape metal, especially steel, into desired forms through the application of force. While both processes serve the purpose of forging, they differ significantly in their methodologies, applications, and the types of products they produce. Understanding these differences is crucial for selecting the appropriate forging process for a specific application.

Open-Die Forging Key Features

Versatility in Shape and Size: Suitable for large or uniquely shaped components that cannot be forged in closed dies.
Flexibility in Production: Ideal for low-volume production or one-off items due to the adaptability of the process.
Less Precise Dimensions: The final products may require further machining to achieve the desired dimensions and tolerances.
Greater Material Handling: Larger workpieces can be accommodated, which is beneficial for creating large industrial components.

Open-Die Forging Applications

Large industrial parts like shafts, beams, and simple shapes that require significant material deformation but not intricate details or precise dimensions.

Close-Die Forging Key Features

High Precision and Detail: Produces parts with close tolerances and complex geometries without the need for significant post-forging machining.
Efficiency in High-Volume Production: More suitable for mass production of parts due to the repeatability and speed of the process.
Limited to Smaller Sizes: Generally used for smaller components due to the constraints of the die sizes and press capacities.
Reduced Material Waste: The process is designed to closely approximate the final part shape, minimizing excess material.

Close-Die Forging Applications

Automotive, aerospace, and hardware components that require precise dimensions, complex shapes, and high strength, such as gears, levers, and fasteners.

Conclusion

The choice between open-die and closed-die forging depends on the specific requirements of the project, including the size and complexity of the parts, the precision needed, the volume of production, and cost considerations. Open-die forging is favored for its flexibility and capability to produce large parts, whereas closed-die forging is preferred for its efficiency and ability to produce parts with complex shapes and tight tolerances.

May 23, 2024/by stvvalve

Key Features Of Butterfly Valves

Types Of Butterfly Valves

Operation

Applications

6. Rubber-Lined Butterfly Valves

7. Metal-Seated Butterfly Valves

DIFFERENCES BETWEEN DOUBLE VS. TRIPLE ECCENTRIC BUTTERFLY VALVE

Double Eccentric Butterfly Valves (Double Offset)

Triple Eccentric Butterfly Valves (Triple Offset)

Key Differences (Double/Triple Eccentric Types)

MATERIALS FOR BUTTERFLY VALVES

VALVE BODY

CAST IRON

DUCTILE IRON

CARBON STEEL

STAINLESS STEEL

Advantages Of Stainless Steel Butterfly Valves

Common Grades Of Stainless Steel For Butterfly Valves

Applications

Selection Considerations

DUPLEX & SUPERDUPLEX STEEL

Characteristics Of Duplex And Super Duplex Stainless Steel Butterfly Valves

Common Grades

Applications

Selection Considerations

NICKEL ALLOY STEEL

Characteristics

Common Nickel Alloys Used For Butterfly Valves

Applications

Selection Considerations

TITANIUM AND TITANIUM ALLOYS

Characteristics

Applications

Selection Considerations

ALUMINIUM

BRONZE

NICKEL ALUMINIUM BRONZE

CPVC

PP/PE

VALVE SEAT

SOFT SEATED BUTTERFLY VALVE (“RESILIENT”)

Key Features

Applications

Considerations

METAL SEATED BUTTERFLY VALVE

Key Features

Materials For Metal Seats

1. Stainless Steel

2. Carbon Steel

3. Alloy Steel

4. Titanium

5. Hastelloy

6. Inconel

7. Monel

8. Bronze

Applications

Considerations

1. Body

2. Ball

Special Treatments For The Ball Of A Ball Valve

1. Hard Coatings

2. Soft Coatings

3. Electroless Nickel Coating

4. Nitriding

5. Cryogenic Treatment

6. Molybdenum Disulfide Coating

7. Fusion Bonded Epoxy Coating

3. Seats

Special Treatments For The Seats Of A Ball Valve

1. Soft Seating Materials

2. Metal Seating

3. Elastomeric And Composite Materials

4. Surface Treatments

5. Seat Design Enhancements

4. Stem

5. Handle Or Actuator

6. Packing

7. O-Rings/Gaskets

8. Bonnet

9. End Connections