What is a Trunnion Mounted Ball Valve?

When it comes to high-performance flow control, trunnion mounted ball valves are one of the most reliable and efficient solutions. Whether you're in the oil and gas industry, chemical processing, water treatment, or any critical infrastructure, understanding how a trunnion mounted ball valve works can help you select the right product for your needs. In this article, we'll explore everything you need to know about trunnion mounted ball valves: their design, how they operate, advantages, applications, and why choosing a quality manufacturer matters.

Understanding the Basics: What is a Trunnion Mounted Ball Valve?

A trunnion mounted ball valve is a type of ball valve where the ball is mechanically anchored by trunnions (shaft-like supports) at both the top and bottom. Unlike floating ball valves where the ball is free to move slightly inside the valve body, the trunnion design secures the ball in place, allowing it to rotate precisely without shifting under pressure.

The valve operates by turning the ball to open or close the flow of media (such as gas or liquid) through it. With a trunnion-supported ball, the valve can handle higher pressures and larger diameters more efficiently while maintaining lower operating torque.

Key Components:

• Ball: The spherical closure element.

• Trunnions: Upper and lower stems that hold the ball firmly.

• Seats: Ring-shaped seals that ensure leak-tight closure.

• Body: The outer casing that houses all components.

• Stem: Connects the ball to the actuator or manual lever.

How Does a Trunnion Mounted Ball Valve Work?

When the handle or actuator turns the stem, the ball rotates around a fixed axis supported by the trunnions. Because the ball doesn't shift under pressure, the sealing performance is more consistent, especially in large diameter and high-pressure applications.

The seats in a trunnion ball valve are typically spring-loaded against the ball. This ensures a tight seal even at low pressures, enhancing reliability.

Trunnion Mounted vs. Floating Ball Valve: What's the Difference?

Advantages of Trunnion Mounted Ball Valves

• Low Operating Torque: Less force is needed to operate the valve, reducing actuator size and cost.

• Superior Sealing Performance: Fixed ball and spring-loaded seats maintain tight seals.

• High Pressure Capability: Perfect for high-pressure and high-temperature applications.

• Longer Lifespan: Reduced wear and better support mean the valve lasts longer.

• Double Block and Bleed Capability: Many designs allow isolation and venting between two seals.

Types of Trunnion Mounted Ball Valves

• Side-Entry Trunnion Ball Valve: Valve body is split horizontally for easier maintenance.

• Top-Entry Trunnion Ball Valve: Valve body opens from the top; allows inline maintenance.

• Fully Welded Trunnion Ball Valve: No body bolts; ideal for buried or subsea service.

Each type offers unique advantages depending on maintenance needs, installation environment, and project requirements.

Common Applications

• Oil & Gas (upstream, midstream, downstream)

• Chemical and Petrochemical Industries

• Power Plants

• Water and Wastewater Treatment

• LNG Plants

• Pipeline Transportation

Why Choosing a Trusted Manufacturer Matters

When selecting a trunnion mounted ball valve, the quality of materials, precision of manufacturing, and expertise of the supplier significantly impact the valve's performance and longevity.

As a professional valve manufacturer with decades of experience, we design and produce trunnion mounted ball valves that meet the highest industry standards, such as API 6D, ISO, and fire-safe certifications. Our valves are rigorously tested to ensure excellent sealing, easy operation, and reliable service life even in the most demanding environments.

Whether you need standard configurations or customized solutions, we provide:

• Superior Material Selection: Forged steel, stainless steel, exotic alloys.

• Advanced Engineering: Precision machining and sealing technology.

• Comprehensive Testing: Pressure testing, fire testing, low-emission compliance.

• Expert Support: Engineering consultation, after-sales service, and fast delivery.

Conclusion

A trunnion mounted ball valve is an essential component in many high-demand industrial systems. Its fixed-ball design offers superior performance under high pressures and large sizes, making it the go-to choice for critical applications.

Understanding the structure and benefits of trunnion mounted ball valves helps ensure the right choice for your projects. If you're looking for reliable, high-quality trunnion ball valves backed by professional engineering and outstanding service, we are ready to support you.

Contact us today to learn more about our solutions and how we can help enhance the safety, efficiency, and success of your operations!