Pneumatic Ball Valve
Pneumatic ball valve can be divided according to its structure:
1.Floating pneumatic ball valve
The ball of pneumatic ball valve
is floating. Under the action of medium pressure, the ball can produce certain displacement and press on the sealing surface of the outlet end to ensure the seal of the outlet end. The floating pneumatic ball valve has simple structure and good sealing performance, but the load bearing the working medium of the ball is transmitted to the outlet sealing ring. Therefore, it is necessary to consider whether the sealing ring material can withstand the working load of the spherical medium. This structure is widely used in low - and medium-pressure ball valves.
2.Fixed ball pneumatic ball valve
The sphere of the pneumatic ball valve is fixed and does not move after compression. Fixed ball valves are equipped with floating seats. After medium pressure, the seat moves and the sealing ring is pressed on the ball to ensure sealing. Usually the upper and lower axles of the sphere are equipped with bearings, which have small operating torque and are suitable for high pressure and large caliber valves.
In order to reduce the operating torque of pneumatic ball valves and increase the reliability of sealing, oil seal ball valves have appeared in recent years. It injects special lubricating oil between the sealing surfaces to form a layer of oil film, which enhances the sealing performance, reduces the operating torque, and is more suitable for high pressure and large caliber ball valves.
3.Pneumatic ball valve with elastic ball
The ball of the pneumatic ball valve is elastic. Both the ball and seat sealing ring are made of metal materials, and the seal pressure is very high. This valve is suitable for high temperature and high pressure medium.
The elastic sphere is obtained by opening an elastic groove at the lower end of the inner wall of the sphere. When closing the channel, seal the ball with the wedge head of the stem. Loosen the wedge head before turning the ball, and the ball returns to its original shape, leaving a small gap between the ball and the seat to reduce friction and operating torque on the sealing surface.
Pneumatic ball valves can be divided into straight, three-way and right-angle types according to their access position. The latter two ball valves are used to distribute the medium and change the flow direction of the medium.