Trunnion Ball Valve–Definitive Guide

Brief overview:
Trunnion ball valve is a high-performance ball valve, which is suitable for long-distance pipelines and general industrial pipelines. Its strength, safety, and harsh environment resistance have been specially considered during design, and are suitable for various corrosive and non-corrosive medium. Compared with the floating ball valve, when working, the force generated by the fluid pressure on the ball is transmitted to the bearing, and the ball will not move to the valve seat, so the valve seat will not withstand excessive pressure, so the fixed ball valve Low torque, small deformation of valve seat, stable sealing performance and long service life, suitable for high pressure and large diameter applications. The advanced spring pre-seat assembly has self-tightening characteristics and realizes upstream sealing. Each valve has two valve seats and can be sealed in every direction, so the installation has no flow direction restrictions and is bidirectional. This valve is generally installed horizontally.

Trunnion ball valve has two-piece and three-piece valve body structure, the middle flange is connected by bolts, the sealing is reinforced PTFE and other soft sealing materials inserted into the stainless steel ring, and the spring guarantee valve is provided at the rear of the steel ring The seat is close to the sphere, keeping it sealed. The upper and lower valve stems are equipped with PTFE bearings to reduce friction and save effort. The bottom of the small shaft is provided with an adjusting piece to ensure the position of the joint between the ball and the sealing ring. Full diameter: The valve’s flow aperture is the same as the inner diameter of the pipeline to facilitate pipeline cleaning.

Performance advantages:
1. Labor-saving operation: The ball is supported by the upper and lower bearings, reducing friction and eliminating the excessive torque caused by the huge sealing load formed by the inlet pressure pushing the ball and the sealing seat.
2. Reliable sealing performance: the elastic material sealing ring is embedded in the stainless steel seat, and the spring at the end of the metal seat is provided with a spring to ensure that the sealing ring has sufficient preload. When the sealing surface wears out during use, the valve continues under the action of the spring Ensure good sealing performance.
3. Fireproof structure: In order to prevent the soft seal ring from burning out due to sudden heat or fire, and a large leak occurs, and to promote the fire, a fireproof seal ring is provided between the ball and the valve seat. When the seal ring burns, the spring force Under the action, the valve seat sealing ring is quickly pushed onto the sphere to form a metal-to-metal seal, which plays a certain degree of sealing effect. The fire resistance test meets the requirements of APl6FA and APl607 standards.
4. Automatic pressure relief function: when the medium pressure in the stagnation of the valve abnormally rises beyond the pre-spring force of the spring, the valve seat moves backwards away from the ball to achieve the effect of automatic pressure relief, and the valve seat automatically resets after the pressure relief
5. Drainage pipeline: Drainage holes are provided on the upper and lower sides of the valve body to check whether the valve seat is leaking. In operation, when the valve is fully open or fully closed, the pressure in the middle cavity is removed, and the filler can be directly replaced; the middle cavity can be discharged Retentate, reduce the pollution of the valve by the medium.


1. Double blocking and discharge function: Trunnion ball valve adopts spring preloaded floating seat, no matter when the valve is fully open or fully closed, the upstream and downstream sides of the seat block the fluid, and the retentate in the valve body cavity passes through the discharge valve excretion.
2. Automatic pressure relief function: when the temperature of the medium in the valve body cavity rises and causes abnormal pressure increase, it does not need to pass the safety valve, but can automatically relieve pressure only by the function of the seat, which ensures the safety of the valve when conveying the liquid medium. Sex is very important.
3. Fire safety structure: The valves are equipped with fire safety functions, and their design and manufacture follow API 607 and API 6FA specifications.

1. Sealing emergency fat injection and rescue: due to the foreign body in the medium or fire caused by the accidental failure of the valve seat seal, the grease injection valve provides a quick connection to the grease injection gun, and the imported pump quickly and quickly injects the sealing grease into the sealing part of the valve seat. Mitigate the leak.
2. Reliable valve stem sealing and low operating torque: In addition to the standard sealing ring, the packing gland is also provided with an O-ring seal. The double seal ensures the reliability of the valve stem seal; the additional graphite packing and sealing grease Injection minimizes stem leakage after a fire. Stem sliding bearings and thrust bearings make the valve easy to operate.
3. Full-diameter or reduced-diameter: Full-diameter or reduced-diameter structure can be selected as required. The flow aperture of the full-bore valve is the same as the inner diameter of the pipeline, which is convenient for pipeline cleaning.
4. The valve stem can be lengthened: according to the needs of installation or operation, the valve stem can be lengthened. The extended rod ball valve is especially suitable for the occasions of laying underground pipelines such as city gas. The length of the extended stem is determined according to customer needs.
5. Flexible operation: The use of valve seat and stem bearing with small friction coefficient and good self-lubricity greatly reduces the operating torque of the valve. Therefore, even if no sealing grease is provided, the valve can be operated flexibly for a long period of time.

Application range :
Trunnion ball valve is suitable for various pipelines of Class150~Class2500, applicable temperature: -196~350℃, used to cut off or connect the medium in the pipeline, choose different materials, and can be respectively suitable for conveying water, steam, oil Products, nitric acid, acetic acid, oxidizing media, urea, etc., are widely used in petroleum refining, long-distance pipelines, chemical industry, papermaking, pharmaceutical, water conservancy, electric power, municipal, steel and other fields.
Trunnion ball valve is driven by worm gear, manual, pneumatic or electric.
Trunnion ball valve generally adopts flange connection, but can also use butt welding connection.