The spool ball of the floating ball valve moves between the two seat sealing rings with the help of medium pressure, while the spool ball of the trunnion mounted ball valve is connected with the valve stem and rotates around the center of the valve stem, and the floating seat support ring.

Floating Ball Valve

The ball of the floating ball valve is floating. Under the action of medium pressure, the ball can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure the seal of the outlet end. The floating ball valve is small in size, light in weight, simple in structure and good in sealing performance. The load of the working medium that the ball bears is all transmitted to the outlet sealing ring, so it is necessary to consider whether the material of the sealing ring can withstand the working load of the ball medium. This structure is widely used in medium and low pressure ball valves.

Trunnion Mounted Ball Valve

The ball of the trunnion mounted ball valve is fixed and will not move after being pressed. The trunnion mounted ball valve is equipped with floating valve seat. After being subjected to medium pressure, the valve seat will move to make the sealing ring tightly press on the ball to ensure sealing. Usually, bearings are installed on the upper and lower shafts of the ball, and the operating torque is small, which is suitable for high pressure and large diameter valves.

How to Identify?

A simple way to distinguish between the two ball valves can be by observation. It can be observed by the position of the lower valve stem of the floating ball valve and the trunnion mounted ball valve. If there is a lower valve stem, it is a trunnion mounted ball valve, if it is not, it is a floating ball valve.