Trunnion Ball Valve

Trunnion ball valve, also known as a trunnion-mounted ball valve, is a type of quarter-turn valve that uses a  “free floating” design. It is commonly used in industrial high pressure application,and high-temperature conditions are present. The valve is designed to handle a wide range of pressure applications and offers excellent sealing performance, provide superior application for process applications,hydrocarbon, gas and oil industries.

Trunnion Ball Valve Design Standard

The trunnion mounted ball valve design standard is governed by industry standards according to API 6D ,API608, ANSI, and ASME B16.34,and fire safe according to API 607. These standards define the dimensions, materials, and testing requirements for trunnion ball valves to ensure their performance and reliability. Trunnion ball valves are typically constructed from carbon steel or forged steel, which provides strength and durability in demanding environments.


Main Features of Trunnion Ball Valve

The trunnion mounted ball valve boasts numerous features, with the major ones including:

Emergency Seal

One of the main features of a trunnion mounted ball valve is the emergency seal design. This design ensures that even if the primary seal fails, an emergency sealant injection can be used to prevent leakage and maintain the integrity of the valve.


Trunnion ball valves are equipped with anti-static features to prevent static electricity buildup during operation. This feature reduces the risk of ignition in flammable environments and ensures safe operation.

Blowout Proof Stem

It is designed with a blowout proof stem, which means that the stem is securely anchored to prevent it from being blown out by the pressure inside the valve. This design feature enhances the safety and reliability of the valve.

Fire-Safe Design

It is designed with a fire-safe designed in accordance with API 607 ensure its integrity in case of a fire. This design feature prevents the internal components of the valve from being damaged by high temperatures, allowing the valve to function properly even in extreme conditions.

Fugitive Emissions compliant

Fugitive Emissions compliant is designed to minimize the release of harmful emissions into the atmosphere. These valves are essential in industries where environmental protection and safety are top priorities, such as oil and gas, petrochemical, and chemical processing. They are equipped with advanced sealing mechanisms and gaskets to reduce the escape of fugitive emissions, including volatile organic compounds (VOCs). Compliance with strict industry standards, like ISO 15848-1, ensures that these valves contribute to cleaner air and a healthier working environment. Selecting Fugitive Emissions compliant trunnion ball valves is a responsible choice that aligns with environmental regulations and corporate sustainability goals.

Types of trunnion ball valves

Trunnion ball valves come in various configurations, with the two-piece and three-piece types being prominent options. Two-piece trunnion ball valves feature a single body design with two separate end caps, making them relatively easy to assemble and maintain. On the other hand, three-piece trunnion ball valves consist of a body and two end caps, offering increased versatility for servicing and replacement of components. These configurations allow for more flexibility and adaptability in various industrial applications, providing efficient flow control and reliability.

Main Parts of Trunnion Ball Valve


The body  is the outer casing that houses the internal components. It is typically made of carbon steel or forged steel and is designed to withstand high pressures and temperatures.


The ball is a crucial component of the trunnion ball valve. It is connected to the trunnion and rotates within the valve body to control the flow of fluid. The ball is typically made of stainless steel,electroless nickel plating or other corrosion-resistant materials.


The seat is the sealing surface that ensures a tight seal between the ball and the valve body. soft seated trunnion ball is typically made of materials such as RPTFE,PEEK or other resilient materials to provide excellent sealing performance.

The metal seated design of a trunnion ball valve offers exceptional durability and reliability, making it ideal for high-pressure and high-temperature applications. With metal-to-metal sealing, these valves ensure tight shut-off and are resistant to wear and erosion. They are widely used in industries like oil and gas, where dependable performance under extreme conditions is essential.


The trunnion is a fixed shaft that supports the ball and allows it to rotate within the valve body. It is typically made of stainless steel or other corrosion-resistant materials to withstand high pressures and temperatures.


The stem is the component that connects the ball to the actuator. It is designed to withstand the torque required to open and close the valve and is typically made of stainless steel or other high-strength materials.


The injection fittings allows for the emergency sealant injection in case of a failure of the primary seal. It ensures that the valve remains leak-tight and provides additional safety measures.

Trunnion Ball Valve Selection

When choosing a trunnion mounted ball valve, it’s essential to take into account four key factors: material, pressure, size, and temperature requirements.


When selecting a trunnion ball valve, it is essential to consider the material of construction. Carbon steel and forged steel are commonly used materials that provide strength and durability in demanding environments.

The main material is duplex steel F51 and F53, special material Monel and hastelloy.


The pressure rating of the valve should be selected based on the application requirements. It is important to choose a trunnion ball valve that can withstand the maximum pressure expected in the system.

Port & Bore Size

The port and  Bore size should be selected based on the desired flow rate and system requirements. Full port valves offer unrestricted flow, while reduced port valves can reduce the flow rate.

Full Port

A full port trunnion ball valve has a larger ball and seat opening, allowing for maximum flow and reduced pressure drop. It is suitable for applications that require high flow rates.

Reduced Port

A reduced port  has a smaller ball and seat opening, which can restrict the flow rate. It is suitable for applications where a lower flow rate is acceptable.


The temperature of the fluid being handled by the valve is an important factor to consider. Trunnion ball valves are designed to withstand high temperatures and can be selected based on the maximum temperature expected in the system.


Trunnion Mounted vs Floating Ball Valve

A trunnion-mounted ball valve and a floating ball valve are two different types of ball valves. The key difference lies in the way the ball is supported within the valve body.

A trunnion-mounted ball valve uses a fixed trunnion to support the ball, allowing it to rotate within the valve body. This design provides excellent sealing performance and is suitable for high-pressure applications.

On the other hand, a floating ball valve relies on the pressure of the fluid to push the ball against the seat, creating a seal. This design is suitable for low-pressure applications.

Why and How to Maintain Trunnion Ball Valves

Maintaining trunnion ball valves is of paramount importance to guarantee their efficient and safe operation. This valve applications in controlling fluid flow in various industries, such as oil and gas, petrochemical, and power generation. Neglecting their maintenance can lead to costly downtime, safety risks, and reduced valve lifespan. To ensure valve performance, a maintenance regimen should encompass regular inspection, lubrication, and addressing any signs of wear, leaks, or damage. Following manufacturer-recommended maintenance schedules is essential, as it ensures compliance with industry standards and safety regulations. Ultimately, diligent maintenance not only prolongs the life of trunnion ball valves but also safeguards equipment and processes.

Flushing is Necessary

Regular flushing is necessary to remove any debris or contaminants from the valve body. This helps ensure smooth operation and prevents any potential blockages.

Repairs and Spraying are Crucial

Regular repairs and spraying of the valve components are crucial to maintain their integrity and performance. This includes inspecting and replacing any damaged or worn-out parts.

Contact Us to Buy

If you are interested in purchasing unique design trunnion ball valves, please feel free to contact us wechat 8615825400387. We offer a wide range of trunnion ball valves that meet industry standards and provide reliable performance in demanding applications.


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