Trunnion Ball Valve: Exploring Its Unique Design and Functionality

Trunnion Ball Valve: A Comprehensive Guide to Function and Applications

Definition of Trunnion Ball Valve


A trunnion ball valve is a trunnion ball designs remarkable piece of engineering designed to regulate fluid flow in a variety of industries. This type of traditional ball valves features a spherical-shaped closure (the ball) with a hole through its center. The ball is held in place by two trunnions, which are shafts that extend from the ball into the valve body. When the valve is open, fluid flows through the hole in the ball, and when it is closed, the ball rotates to block the flow, creating a tight seal.

Table of Contents

Common type of trunnion ball valves

Side Entry Ball Valve: Versatility and Easy Maintenance

A side entry ball valve is one of types of ball valves where the ball and stem are assembled from the side of the valve body. This design offers several advantages:

Versatility in Installation and Piping Systems

Side entry ball valves are highly versatile and can be installed in various piping systems. Their side entry construction allows for easy integration into existing pipelines without the need for major modifications. This flexibility makes side entry ball valves suitable for a wide range of applications, including oil and gas, petrochemical, water treatment, and more. Whether it’s a new installation or a retrofit project, side entry ball valves provide convenient options for system integration.

Easy Maintenance and Repairs

One significant advantage of side entry ball valves is their ease of maintenance and repairs. The side entry design allows for convenient access to the valve internals, including the ball, seats, and stem, without the need for complete removal from the pipeline. This accessibility simplifies routine maintenance tasks, such as inspection, cleaning, and replacement of internal components. With side entry ball valves, operators can minimize downtime, reduce maintenance costs, and quickly address any issues that may arise.

A top entry ball valve is a type of ball valve where the ball and stem are assembled from the top of the valve body. This design offers distinct advantages:

Enhanced Performance and Flow Characteristics

Top entry ball valves are known for their enhanced performance and improved flow characteristics. The top entry construction allows for a larger ball size and a more efficient flow path, resulting in reduced pressure drop and enhanced flow capacity. These valves are ideal for applications that require high flow rates and minimal flow restrictions. Whether it’s a system with demanding flow conditions or the need for precise flow control, top entry ball valves deliver optimal performance.

Superior Serviceability and Reduced Downtime

One of the key benefits of top entry ball valves is their superior serviceability. With their top entry design, these valves enable easy access to the internals for inspection, maintenance, and repairs. The ability to remove the ball and stem assembly from the top of the valve body simplifies maintenance tasks, reduces downtime, and minimizes the need for complete valve removal from the pipeline. This serviceability feature ensures efficient operation, streamlined maintenance procedures, and cost-effective valve management.

Design and Construction

Trunnion ball valves are meticulously designed and constructed to withstand high pressures, temperatures, and demanding environments. The key components of a trunnion ball valve include the body, ball, seats, stem, and trunnions.

  1. Body: The body of a trunnion ball valve is typically made of durable materials such as carbon steel, stainless steel, or alloy steel. These materials ensure strength, corrosion resistance, and longevity. The body is designed to withstand the forces exerted by the flowing fluid and to provide a secure enclosure for the internal components.
  2. Ball: The ball is the central element of the trunnion ball valve. It is usually made of materials such as stainless steel, brass, or other alloys, depending on the specific application. The ball is carefully machined and precision-ground to ensure a tight seal when closed and efficient flow when open.
  3. Seats: The seats of a trunnion ball valve play a vital role in achieving a tight seal. They are positioned around the ball to prevent leakage when the valve is closed. The seats are made from resilient materials such as PTFE (Polytetrafluoroethylene) or reinforced PTFE to withstand high pressures and offer excellent sealing properties.
  4. Stem: The stem connects the actuator or handle to the ball and allows for the rotation of the ball to open or close the valve. It is designed to transmit the necessary torque and withstand the operational forces. Additionally, trunnion ball valves often feature stem seals to prevent leakage along the stem.
  5. Trunnions: The trunnions are the shafts that extend from the ball into the valve body, providing support and anchoring the ball in place. They are carefully engineered to handle the forces exerted on the ball and maintain its alignment within the valve body, ensuring proper sealing and smooth operation.

Body Materials Used in Trunnion Ball Valves

A close-up image of a trunnion ball valve, a type of industrial valve used for controlling the flow of fluids. The valve features a spherical ball with a hole in the center, which rotates to allow or block the passage of liquids or gases. The trunnion design ensures stability and reduces friction, making it ideal for high-pressure and large-scale applications in industries such as oil and gas, petrochemical, and water treatment
Source: SLB

Trunnion ball valves are available in a wide range of body materials, each chosen based on its suitability for specific applications and fluid types. Here are some commonly used body materials:

  1. Carbon Steel: Carbon steel bodies are widely used due to their strength, durability, and cost-effectiveness. They offer excellent resistance to corrosion and are suitable for applications involving non-corrosive fluids or moderate corrosive environments.
  2. Stainless Steel: Stainless steel is a popular choice for trunnion ball valve bodies, especially in applications where corrosion resistance is critical. Different grades of stainless steel, such as 316 or 304, offer varying levels of resistance to chemicals and harsh environments.
  3. Alloy Steel: Alloy steel bodies provide superior strength and resistance to extreme temperatures and pressures. These valves are commonly used in applications involving high-pressure fluids or corrosive environments.
  4. Duplex Stainless Steel: Duplex stainless steel combines the best attributes of austenitic and ferritic stainless steels, offering excellent corrosion resistance and high mechanical strength. Trunnion ball valves made from duplex stainless steel are ideal for applications that demand both durability and resistance to corrosive substances.

In conclusion, trunnion ball valves are versatile fluid control solutions known for their reliable performance and excellent sealing capabilities. With various types available and a sturdy construction consisting of high-quality body materials, these valves ensure efficient flow control in a wide range of industries and applications. Choose the appropriate trunnion ball valve for your specific needs, and experience the benefits of precise fluid control and secure sealing in your operations.

Operating Torque: Effortless Control and Energy Efficiency

Smooth Operation and Reduced Torque

Trunnion ball valves are designed to provide smooth and effortless operation, allowing for precise control of fluid flow. The innovative double trunnion design significantly reduces operating torque compared to other valve types. By distributing the torque evenly across the trunnions, these valves minimize the force required to open and close the valve. This not only eases the strain on operators but also enhances the overall energy efficiency of the system.

Enhanced Efficiency and Cost Savings

The reduced operating torque of trunnion ball valves translates into tangible benefits for businesses. With lower torque requirements, operators can quickly and easily operate the valves, resulting in increased efficiency and productivity. Moreover, the decreased torque demand reduces the load on actuators, leading to energy savings and prolonged actuator life. These energy-efficient features contribute to lower operational costs and a more sustainable approach to fluid control systems.

Upstream Pressure Requirements: Managing High-Pressure Environments

A trunnion ball valve shown in a closed position. The valve has a sturdy construction with a spherical ball that has a bore through it. It is designed for high-pressure applications and provides reliable shut-off. The trunnion-mounted ball ensures stability and reduces wear and tear. This type of valve is commonly used in industries such as oil, gas, and petrochemical for controlling the flow of fluids
Source: GWC

Withstanding High-Pressure Conditions

Trunnion ball valves are engineered to handle high-pressure applications with ease. The trunnion-mounted design ensures that the ball is supported on both ends, providing enhanced stability and resistance to the forces exerted by high-pressure fluids. This robust construction enables the valve to maintain its integrity and sealing capabilities even in challenging environments where high upstream pressures are present.

Reliable Sealing under High-Pressure Conditions

One of the key features that make trunnion ball valves suitable for high-pressure applications is the utilization of downstream seats. These seats are positioned downstream of the ball and play a crucial role in achieving a tight seal when the valve is closed. The upstream pressure acts on the ball, pushing it against the downstream seats, which creates a secure seal and prevents any potential leakage. This reliable sealing mechanism ensures the safety and efficiency of operations, providing peace of mind in high-pressure environments.

Downstream Seats for Tight Seal: Ensuring Leak-Free Operations

Dual-Sealing System

Trunnion ball valves incorporate downstream seats as part of their dual-sealing system. When the valve is in the closed position, the upstream pressure pushes the ball against the downstream seats, creating a primary seal. This primary seal provides a tight closure, preventing any leakage or unwanted flow. The downstream seats act as an additional layer of protection, enhancing the sealing performance and ensuring leak-free operations.

Resilient Seat Materials

To ensure a reliable and long-lasting seal, downstream seats in trunnion ball valves are typically made from high-quality materials such as PTFE (Polytetrafluoroethylene) or reinforced PTFE. These materials possess excellent chemical resistance, low friction properties, and exceptional resilience, making them ideal for demanding applications. The resilient seat materials allow for repeated compression and decompression cycles, maintaining a tight seal over an extended service life.

Versatility and Flexibility

The downstream seats in trunnion ball valves offer versatility and flexibility in terms of sealing performance. Depending on the specific application requirements, different seat materials can be selected to handle various fluids, temperatures, and pressures. This adaptability allows trunnion ball valves to accommodate a wide range of operating conditions while providing a reliable and tight seal.

Floating and Trunnion-Mounted Ball Valves

Floating Ball Valves

Floating ball valves are a popular choice for a wide range of applications. In this design, the ball is allowed to float slightly downstream, relying on the line pressure to create a seal against the downstream seat when the valve is closed. Floating ball valves are commonly used in low and medium-pressure applications, where tight shutoff is not a critical requirement. These valves offer excellent flow control and are often more cost-effective compared to trunnion-mounted ball valves.

Trunnion-Mounted Ball Valves

Trunnion-mounted ball valves are preferred for applications that demand tight shutoff and enhanced sealing performance. The trunnion design provides additional support to the ball, ensuring it remains in position even under high pressure. The upstream pressure acts on the ball, pushing it against the downstream seat to create a secure seal. Trunnion ball valves are well-suited for high-pressure and critical applications where reliable sealing is of utmost importance.

Applications of Trunnion Ball Valves: Versatility and Reliability

A trunnion ball valve, a mechanical device used for regulating fluid flow, shown in an open position. The valve consists of a spherical ball with an aperture in the center, allowing the passage of liquids or gases. The trunnion design provides stability and reduces friction, making it suitable for high-pressure applications in industries like oil, gas, and water treatment
Source: Sern Ball valve

Trunnion ball valves find extensive use across various industries due to their versatility, reliability, and excellent sealing capabilities. Some notable applications include:

Common Uses in the Chemical Industry

In the chemical industry, trunnion ball valves are widely employed to regulate the flow of corrosive and hazardous fluids and Refining industry. These valves’ robust construction and use of seat materials compatible with aggressive chemicals make them suitable for handling acids, caustic substances, and other corrosive mediums. Trunnion ball valves offer reliable performance, preventing leakage and ensuring the safety of personnel and equipment in chemical processing plants.

Usage in the Gas Industry

The gas industry relies on trunnion ball valves for their ability to withstand high pressures and provide reliable shut-off capabilities. Whether it is natural gas, propane, or other gases, these valves ensure efficient flow control and tight sealing to prevent any leakage or fugitive emissions. Trunnion ball valves are commonly used in gas pipelines, distribution systems, and gas processing facilities,industrial gas processing plants where reliable and safe operation is paramount.

Other Applications

Trunnion ball valves are versatile enough to find application in various other industries. They are often utilized in oil refineries, petrochemical plants, power generation facilities, and water treatment plants. Trunnion ball valves offer exceptional performance in controlling the flow of crude oil, refined products, water, steam,hydrocarbon industries and other fluids, even in demanding environments.

Advantages of Using a Trunnion Ball Valve: Optimal Performance and Reliability

Trunnion ball valves offer numerous advantages that make them a preferred choice in fluid control systems. Let’s explore some of the key benefits:

Reduced Pressure Losses during Flow of Fluid

One significant advantage of trunnion ball valves is their ability to minimize pressure losses during the flow of fluid. The full-bore design of these valves ensures a larger flow area, allowing for efficient and unrestricted fluid movement. The smooth internal passages and low flow resistance result in minimal pressure drop, maximizing system performance and reducing energy consumption. This advantage is particularly crucial in applications where maintaining high flow rates and minimizing pressure losses are paramount.

Reliable Sealing Performance

Trunnion ball valves are known for their exceptional sealing capabilities. The trunnion-mounted design, combined with downstream seats, ensures a secure and reliable seal even under high-pressure conditions. This reliable sealing performance prevents any potential leakage, enhancing the safety and integrity of the fluid control system. Whether dealing with aggressive chemicals, high pressures, or challenging environments, trunnion ball valves deliver peace of mind by maintaining tight seals and preventing costly fluid loss.

Durability and Longevity

Trunnion ball valves are constructed using robust materials and undergo stringent quality control measures, ensuring durability and longevity. The body materials, such as carbon steel, stainless steel, or alloy steel, provide excellent resistance to corrosion, erosion, and wear. The use of resilient seat materials, such as PTFE or reinforced PTFE, further enhances the valves’ lifespan. These durable components, combined with precise engineering and manufacturing processes, result in trunnion ball valves that can withstand harsh operating conditions and offer prolonged service life.

Versatility in Operating Conditions

Trunnion ball valves are highly versatile and adaptable to a wide range of operating conditions. They are capable of handling high pressures, extreme temperatures, corrosive fluids, and demanding environments. This versatility makes them suitable for diverse industries, including oil and gas, chemical, power generation,Power generation industry,hydrocarbon industriesand more. Trunnion ball valves can be customized to meet specific requirements, such as fire-safe or cryogenic service, further expanding their applicability in different applications and industries.

Disadvantages of Using a Trunnion Ball Valve: Considerations for Implementation

While trunnion ball valves offer numerous advantages, it is important to consider their limitations and potential disadvantages in certain situations:

Higher Initial Cost

Compared to other types of valves, trunnion ball valves generally have a higher initial cost. The robust construction, precise engineering, and quality materials contribute to the higher price point. However, it’s important to note that this cost is often justified by the long-term reliability, durability, and reduced maintenance requirements of trunnion ball valves.

Bulkier Design and Space Requirements

Trunnion ball valves typically have a bulkier design compared to other valve types due to their trunnion-mounted ball and robust construction. As a result, they may require more space for installation and operation. When retrofitting existing systems or working with limited space constraints, it is essential to consider the dimensions and clearance required for trunnion ball valves to ensure proper installation and functionality.

Limited Suitability for Low-Pressure Applications

While trunnion ball valves excel in high-pressure applications, they may not be the most efficient choice for low-pressure systems. Floating ball valves, which operate based on line pressure, are often more suitable for low and medium-pressure applications due to their lower torque requirements and cost-effectiveness. It is important to assess the specific pressure requirements of the system and select the appropriate valve type accordingly.

Trunnion ball valves offer significant advantages in terms of reduced pressure losses, reliable sealing performance, durability, and versatility. However, it is important to consider factors such as initial cost, space requirements, and suitability for low-pressure applications when implementing trunnion ball valves. By understanding the advantages and limitations, engineers and operators can make informed decisions and leverage the benefits of trunnion ball valves in their fluid control systems.


Ease of Operation: User-Friendly Design for Seamless Control

One of the key factors that contribute to the success of any fluid control system is the ease of operation. Ball valves, including trunnion ball valves, are designed with user-friendliness in mind. Here are some aspects that enhance the ease of operation of trunnion ball valves:

Smooth Handle or Actuator Operation

Trunnion ball valves are typically equipped with handles or actuators that facilitate manual or automated control of the valve. The handles are designed to provide a comfortable grip, allowing operators to easily rotate the valve between open and closed positions. Actuators, such as pneumatic or electric actuators, offer the convenience of remote operation. Both options provide smooth and precise control, enabling operators to regulate fluid flow with minimal effort and high accuracy.

Clear Position Indication

Trunnion ball valves often feature clear position indication mechanisms to provide visual feedback on the valve’s status. This can be in the form of a handle position indicator or an actuator position indicator. These indicators help operators quickly and accurately determine whether the valve is fully open, fully closed, or somewhere in between. The clear position indication minimizes the chances of error and ensures proper valve positioning, enhancing operational efficiency and reducing the risk of unintended flow conditions.

Ergonomic Design and Accessibility

Trunnion ball valves are designed with ergonomics in mind, considering the comfort and ease of use for operators. The handles or actuators are positioned in a way that allows for convenient access and operation, even in tight or hard-to-reach spaces. The ergonomic design reduces strain and fatigue on operators, enabling them to operate the valve comfortably for extended periods. Additionally, the accessibility of key components, such as stem seals or internals, facilitates routine maintenance and servicing, further enhancing ease of operation and maintenance efficiency.

Integration with Control Systems

Trunnion ball valves can be integrated with control systems, such as distributed control systems (DCS) or programmable logic controllers (PLC), for enhanced automation and ease of operation. By connecting the valve to a control system, operators can control and monitor the valve remotely, set up specific operating parameters, and even incorporate valve status into broader system control and monitoring. This integration streamlines operations, improves efficiency, and allows for centralized control of multiple valves within a system.

Anti-Blowout Stems: Ensuring Stem Integrity and Operator Safety

Trunnion ball valves often incorporate anti-blowout stem features to enhance stem integrity and ensure operator safety. Here’s an overview of this important design element:

Preventing Stem Ejection

Anti-blowout stems are designed to prevent the stem from being blown out of the valve body due to high pressures or other extreme conditions. They typically feature a stem-retaining mechanism, such as a shoulder, collar, or key, that securely holds the stem in place. This design prevents the stem from becoming dislodged or ejected, maintaining the valve’s functionality and integrity, even under demanding operating conditions.

Operator Safety

The inclusion of anti-blowout stems in trunnion ball valves prioritizes operator safety. By preventing stem ejection, these valves reduce the risk of injury to operators and minimize the potential for process disruptions. The anti-blowout stem design provides added assurance that the stem will remain securely in place, even during high-pressure situations, giving operators peace of mind and confidence in the valve’s reliability.

Nominal Sizes: Accommodating Different Pipeline Requirements

Trunnion ball valves are available in a range of nominal sizes, allowing for compatibility with various pipeline requirements. Here’s an overview of how nominal sizes are utilized:

Matching Pipeline Dimensions

Nominal sizes refer to the standardized dimensions assigned to valves, pipes, and fittings. Trunnion ball valves are manufactured in various nominal sizes to accommodate the specific dimensions of the pipeline they will be installed in. Whether it’s a small-diameter pipeline or a large-scale industrial system, selecting the appropriate nominal size ensures proper fit and efficient fluid flow within the pipeline.

Size Range and Flexibility

Trunnion ball valves are available in a broad size range, offering flexibility to suit diverse applications. They can be found in small sizes, such as 1/2″ or 3/4″, as well as larger sizes that can exceed several feet in diameter. This wide size range allows for the selection of trunnion ball valves that precisely match the pipeline dimensions, ensuring optimal performance, efficient flow control, and compatibility with existing systems.

Electric Actuator: Automation and Control Convenience

Electric actuators provide automated control and operation of trunnion ball valves. Here’s an overview of their features and benefits:

Remote Operation and Control

Electric actuators offer the convenience of remote valve operation and control. By connecting the actuator to a control system, operators can remotely open, close, or modulate the trunnion ball valve, allowing for precise and efficient fluid flow control. The remote operation capability simplifies valve control in large-scale systems or installations where manual operation may be impractical or inaccessible.

Position Feedback and Monitoring

Electric actuators often include position feedback sensors that provide accurate information about the valve’s position, whether fully open, fully closed, or anywhere in between. This position feedback allows for real-time monitoring of the valve status and facilitates precise control and system diagnostics. It enables operators to assess valve performance, identify potential issues, and ensure optimal system operation.

Integration with Control Systems

Electric actuators can be seamlessly integrated into control systems, such as distributed control systems (DCS) or programmable logic controllers (PLC). This integration allows for centralized control, monitoring, and automation of multiple trunnion ball valves within a system. It enables coordinated operation, remote adjustments, and the incorporation of valve status into broader system control strategies, enhancing overall efficiency and system performance.

Hydraulic Actuator: Robust Power for Demanding Applications

Hydraulic actuators offer robust power and precise control in operating trunnion ball valves. Here’s an overview of their features and benefits:

High Force Output

Hydraulic actuators generate high force output, making them suitable for demanding applications that require strong actuation. The hydraulic power translates into the ability to operate trunnion ball valves under high-pressure conditions or in systems that require substantial actuation force. This robust power ensures reliable operation and precise control, even in challenging environments.

Speed and Response

Hydraulic actuators offer excellent speed and response capabilities, allowing for quick and accurate valve positioning. The hydraulic fluid flow can be precisely regulated, enabling operators to control the actuator’s speed and response characteristics. This responsiveness enhances system performance, allowing for rapid adjustments and precise flow control in dynamic operating conditions.

Reliability and Durability

Hydraulic actuators are renowned for their reliability and durability. They are designed to withstand demanding operating conditions, including high pressures, extreme temperatures, and harsh environments. The robust construction and sealed hydraulic systems minimize the risk of leaks, ensuring consistent and trouble-free performance. Hydraulic actuators are often favored in critical applications where reliability and long-term durability are paramount.

Pressure Rating: Determining Suitable Operating Conditions

The pressure rating of trunnion ball valves indicates the maximum pressure that the valve can withstand without compromising its integrity. Here’s an overview of pressure ratings and their significance:

Defining Maximum Allowable Pressure

Pressure ratings for trunnion ball valves define the maximum allowable pressure that the valves can handle without experiencing structural failures or leaks. The pressure rating is typically determined through rigorous testing and adherence to industry standards. It ensures that the valves are designed and manufactured to withstand the specific pressure conditions of the intended application.

Selection for Safe Operation

The pressure rating plays a crucial role in selecting the appropriate trunnion ball valve for a given system. It ensures that the valve is suitable for the expected operating pressures within the pipeline or system. By matching the pressure rating of the valve to the system requirements, operators can ensure safe and reliable operation, preventing potential valve failures or safety hazards due to pressure overload.

In conclusion, the inclusion of anti-blowout stems enhances stem integrity and operator safety in trunnion ball valves. Nominal sizes allow for compatibility with different pipeline dimensions, while electric and hydraulic actuators offer automation, control convenience, and robust power. Understanding pressure ratings ensures the selection of valves suitable for safe operation within the intended pressure conditions. These features collectively contribute to the optimal performance, reliability, and efficient control of trunnion ball valves in fluid control systems.

Fire-Safe Design: Ensuring Valve Integrity in Fire Emergencies

Trunnion ball valves often incorporate fire-safe design features to maintain their integrity and functionality in the event of a fire. Here’s an overview of the significance and components of fire-safe design:

Maintaining Sealing Integrity

Fire-safe design in trunnion ball valves aims to prevent leakage and maintain sealing integrity even when exposed to high temperatures and fire. These valves undergo rigorous testing and comply with industry standards to ensure their ability to withstand fire conditions and prevent the passage of fluid through the valve during a fire event.

Secondary Metal-to-Metal Sealing

One essential component of fire-safe design is the inclusion of secondary metal-to-metal sealing in addition to the primary seat material. In the event of a fire, the primary seat material may degrade or fail due to high temperatures. The secondary metal-to-metal sealing mechanism, typically located between the ball and seats or stem and body, comes into play to provide an additional barrier against fluid leakage, maintaining a tight seal and preventing fire propagation.

Graphite or Graphite-Based Packing

Another critical aspect of fire-safe design is the use of graphite or graphite-based packing materials. Graphite has excellent thermal resistance properties, making it suitable for high-temperature applications. In trunnion ball valves, graphite or graphite-based packing materials are used to provide effective stem sealing even under fire conditions. The graphite packing acts as a barrier to prevent the escape of fluid or gas through the stem area, enhancing the valve’s fire-safe capabilities.

Metal Inserts and Fire-Resistant Components

Trunnion ball valves may also incorporate metal inserts and fire-resistant components to enhance their fire-safe design. Metal inserts, such as metal-backed seats or fire-resistant rings, provide additional reinforcement and protection against the effects of fire and high temperatures. These inserts help maintain the valve’s sealing integrity and structural strength, ensuring reliable performance during fire emergencies.

Compliance with Industry Standards

Trunnion ball valves with fire-safe design features are designed and tested to meet industry standards and certifications. These standards ensure that the valves can withstand specific fire testing protocols, such as API 607 or ISO 10497. Compliance with these standards provides assurance that the valves have been rigorously evaluated and proven to maintain their sealing integrity and functionality during fire exposure.

Importance of Fire-Safe Design

Fire incidents pose significant risks in industrial settings, and maintaining the integrity of valves during such events is crucial for safety and environmental protection. Trunnion ball valves with fire-safe design features provide an extra layer of protection, helping to contain fire and prevent the spread of hazardous fluids or gases. By ensuring the sealing integrity and functionality of these valves, fire-safe design measures contribute to the overall safety and reliability of fluid control systems.

FAQs About Trunnion Ball Valve

What is the difference between trunnion and floating ball valves?

Trunnion ball valves and floating ball valves differ in their construction and operation. In a trunnion ball valve, the ball is supported by trunnions or shafts, which provide additional stability and reduce torque requirements. In a floating ball valve, the ball is not fixed and relies on the line pressure to create a seal against the downstream seat. Trunnion ball valves are typically used in high-pressure applications, while floating ball valves are suitable for low to medium-pressure applications.

What is a ball and trunnion?

A ball and trunnion is a mechanical component used in trunnion ball valves. The ball refers to the spherical-shaped valve element, which rotates within the valve body to control fluid flow. The trunnions, also known as shafts, are fixed supports located on either side of the ball. These trunnions provide stability and support for the ball, allowing for smoother operation and reduced torque requirements.

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

The main difference between a ball valve and a float ball valve lies in their design and sealing mechanism. In a ball valve, the ball is fixed and operated by a handle or actuator, controlling the flow through the valve. A float ball valve, on the other hand, is a type of ball valve where the ball floats and seals against the downstream seat using line pressure. This design is suitable for low to medium-pressure applications, providing simple and cost-effective flow control.

How does trunnion work?

In a trunnion ball valve, the trunnions or shafts act as support structures for the ball. The trunnions are fixed on both ends of the ball and are mounted within the valve body. The upstream pressure pushes the ball against the downstream seat, creating a seal and preventing leakage. The trunnion design reduces the torque required to operate the valve, providing smoother operation and improved sealing performance, particularly in high-pressure applications.

What is a trunnion valve?

A trunnion valve refers to any valve that incorporates trunnions or shafts to support the valve element, such as a ball or disc. Trunnion valves are commonly used in ball valves and butterfly valves. The trunnions provide stability and reduce torque requirements, enhancing the valve’s sealing performance and overall functionality. Trunnion valves are widely utilized in industries where reliable sealing, precise control, and efficient operation are essential.

What is the difference between floating and trunnion?

The key difference between floating and trunnion valves lies in their design and operation. Floating valves, including floating ball valves, rely on line pressure to create a seal against the downstream seat. The ball or disc is not fixed and floats slightly downstream. Trunnion valves, such as trunnion ball valves, feature trunnions or shafts that support the valve element, providing stability and reducing torque requirements. Trunnion valves are typically used in high-pressure applications, while floating valves are suitable for low to medium-pressure systems.

Why use a trunnion mounted ball valve?

Trunnion mounted ball valves offer several advantages that make them suitable for various applications. These valves provide enhanced sealing performance, particularly in high-pressure conditions. The trunnion design reduces operating torque, resulting in smoother operation and reduced strain on operators and actuators. Trunnion mounted ball valves also offer improved stability and resistance to flow-induced turbulence. Their robust construction and reliable sealing make them ideal for critical applications where tight shut-off and high-pressure capabilities are required.

What is the ball valve trunnion structure?

The ball valve trunnion structure refers to the design configuration where the ball is supported by trunnions or shafts. The trunnions are fixed supports located on both ends of the ball, ensuring stability and reducing torque requirements. This trunnion structure provides enhanced sealing capabilities, as the trunnions help maintain proper alignment of the ball and create a secure seal against the downstream seat. The ball valve trunnion structure contributes to the reliable performance and durability of trunnion ball valves.

Where is the trunnion?

The trunnion in a trunnion ball valve is typically located on both ends of the ball. These trunnions or shafts are fixed within the valve body and provide support for the ball. By positioning the trunnions on either side of the ball, the valve’s design ensures stability, reduced torque requirements, and enhanced sealing performance. The trunnions play a crucial role in the proper functioning of trunnion ball valves, ensuring smooth operation and reliable flow control.


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