TRUNNION

Ball Valve Part: Trunnion

The trunnion is a critical internal component of a trunnion-mounted ball valve, providing structural support and stability to the ball during operation. Unlike floating ball valves where the ball is held only by the stem and sealing forces, the trunnion acts as a fixed pivot point that anchors the ball firmly inside the valve body.

Function of the Trunnion

• Support and Stability
  The trunnion supports the ball at the bottom (and sometimes top), preventing excessive movement during flow and pressure changes, especially in larger valves or high-pressure applications.

• Reduced Operating Torque
  By anchoring the ball, the trunnion reduces the stress on the valve seats, allowing smoother operation with less torque required to open or close the valve.

• Enhanced Sealing Performance
  Trunnion-mounted designs improve sealing reliability under high pressure and minimize wear on the seats by controlling ball movement.

Key Features

• Typically made from durable materials such as stainless steel or carbon steel for strength and corrosion resistance.

• Mounted inside the valve body, aligned precisely to support the rotating ball.

• Works in conjunction with the stem and seats to maintain valve integrity and function.

Applications

• Used predominantly in large-diameter, high-pressure ball valves where enhanced mechanical stability is essential.

• Common in oil & gas, petrochemical, power generation, and other heavy industries requiring reliable flow control.