What Are the Differences Between Floating Ball Valves and Trunnion Ball Valves

Both floating ball valves and trunnion ball valves are general ball valves. They have different structure and are suitable for different applications.

For floating ball valve, the ball is floating, because the ball is only hold by the stem, so the ball will have a small displacement while under the pressure from the media. The greater the medium pressure, the greater the ball offset, the greater the ball pressure on the outlet valve seat, the greater the stem torque. Thus, floating ball valve usually used in medium and low pressure application.

For trunnion ball valves, the ball is anchored in place by the stem and trunnion, and it’s seats are floating. When there is a pressure from media, the ball won’t have any displacement, and the seat will connect to the ball tightly under the pressure of both spring on the seat and the media. Trunnion ball valve has the heavier weight, but it has the lower torque than floating ball valve in the same diameter. Trunnion structure usually used in high pressure and large diameter applications.