trunnion ball valve

How does a trunnion ball valve work?

How Does a Trunnion Ball Valve Work

Introduction to Trunnion Ball Valves

Discover how a trunnion ball valve works, its unique design, and its crucial role in fluid regulation.
Source: Flowserve

A Trunnion Ball Valve is a type of quarter-turn valve that uses a hollow, perforated, and fixed ball to control the flow of fluids. This valve is a crucial device for regulating the flow of fluids such as steam, gas, or oil in pipelines. Trunnion ball valves are extensively used in various industries, including chemical, hydrocarbon, and gas industries, due to their robust design and efficient performance.

Trunnion ball valves are designed with an additional shaft, known as a trunnion, which provides extra support to the ball. This design element significantly reduces the operating torque, making the valve easier to operate. The trunnion design also ensures a tight seal, even under low-pressure conditions, making it suitable for a wide range of applications.

How Does a Trunnion Ball Valve Work?

The functioning of a trunnion ball valve revolves around the role of the trunnion. The trunnion is an additional shaft that supports the ball in the valve. This mechanical anchoring allows the ball to rotate without moving along the axis, facilitating a smooth opening and closing mechanism.

When the valve is in the closed position, the upstream pressure forces the ball against the downstream seat, creating a tight seal. The trunnion absorbs the additional pressure, preventing any leakage. As the valve opens, the flow path is cleared, allowing the flow of fluids. The trunnion design ensures that the valve maintains a tight seal, even under extreme pressures or in the event of a rapid increase in pressure.

The operation of a trunnion ball valve can be manual or automated, with electric, hydraulic, or pneumatic actuators often used in industrial applications. The choice of actuator depends on the specific requirements of the process applications, such as the operating pressures and the type of fluid being controlled.

Trunnion Ball Valve vs. Floating Ball Valve

A Floating Ball Valve is another common type of ball valve. Unlike the trunnion ball valve, the ball in a floating valve is not supported by an additional shaft. Instead, it ‘floats’ between the valve seats, with the pressure forcing the ball against the downstream seat to create a seal.

There are key differences between trunnion and floating ball valves. While both types of valves are used to control the flow of fluids, their design and operation vary significantly. Trunnion ball valves are known for their robust design, lower operating torque, and ability to handle high-pressure applications. On the other hand, floating ball valves are often used in low to medium pressure applications and are typically more compact and cost-effective.

Source: SCV Valves

However, each type of valve has its pros and cons. Trunnion ball valves, with their additional shaft and tight seal, are ideal for high-pressure operations and offer a reliable performance even under extreme conditions. However, they are more complex in design and can be more expensive. Floating ball valves, on the other hand, are simpler and more economical but may not be suitable for high-pressure applications due to the potential for the ball to be forced off the seat, leading to a pressure drop.

In conclusion, the choice between trunnion and floating ball valves depends on the specific requirements of the application, including the pressure conditions, the type of fluid, and the budget constraints.

Components of a Trunnion Ball Valve

A Trunnion Ball Valve is composed of several key components, each playing a crucial role in its operation. Understanding these components and their functions can provide a deeper insight into the workings of this type of valve.

Valve Body

The valve body is the outer casing of the valve and is typically made of robust materials like low-temperature carbon steel to withstand high-pressure applications. It houses the internal components of the valve, including the ball, the seats, and the trunnion.

Ball

The ball is a hollow, perforated sphere that controls the flow of fluids. It can be a solid ball or a hollow ball, depending on the specific design of the valve. The ball is supported by the trunnion and can rotate 90 degrees to open or close the valve.

Trunnion

The trunnion is an additional shaft that supports the ball. This mechanical anchoring reduces the operating torque and ensures a tight seal, even under low-pressure conditions.

Seats

The seats are typically made of soft seat materials or metal, depending on the application. They create a seal when the valve is in the closed position, preventing any leakage.

Stem

The stem is connected to the ball and the actuator. It allows the actuator to rotate the ball, opening or closing the valve.

Actuator

The actuator can be manual or automated (electric, hydraulic, or pneumatic). It provides the force needed to open or close the valve.

FAQs About Trunnion Ball Valves

Why Use a Trunnion Mounted Ball Valve?

Trunnion mounted ball valves are preferred for their robust design and efficient performance. They can handle high-pressure applications and ensure a tight seal, even under low-pressure conditions. Their design reduces the operating torque, making them easier to operate.

Which is Better: Trunnion Mounted or Floating Ball Valve?

The choice between trunnion mounted and floating ball valves depends on the specific requirements of the application. Trunnion ball valves are ideal for high-pressure applications due to their robust design and tight seal. Floating ball valves, on the other hand, are more compact and cost-effective, making them suitable for low to medium pressure applications.

What is a Trunnion Mounted Ball Valve?

A trunnion mounted ball valve is a type of quarter-turn valve that uses a hollow, perforated, and fixed ball to control the flow of fluids. It is designed with an additional shaft, known as a trunnion, that provides extra support to the ball. This design ensures a tight seal and reduces the operating torque, making the valve easier to operate.

Conclusion

In conclusion, a Trunnion Ball Valve is a type of quarter-turn valve that plays a crucial role in controlling the flow of fluids in various industries. It is designed with a hollow, perforated ball and an additional shaft, known as a trunnion, that provides extra support to the ball. This design ensures a tight seal and reduces the operating torque, making the valve easier to operate.

Understanding the workings of a trunnion ball valve, including its key components and their functions, can provide valuable insights for those involved in industries where such valves are used. It can also aid in making informed decisions when choosing between different types of ball valves, such as trunnion mounted and floating ball valves.

The importance of understanding how a trunnion ball valve works cannot be overstated. It not only aids in the proper operation and maintenance of these valves but also contributes to the overall efficiency and safety of the processes in which they are used.

 

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