1. Floating pneumatic ball valve The ball of stainle […]
1. Floating pneumatic ball valve
The ball of stainless steel pneumatic 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 sealing of the outlet end.
Floating stainless steel pneumatic ball valve has a simple structure and good sealing performance, but the load of the ball bearing the working medium is all transferred to the outlet seal ring, so it is necessary to consider whether the seal ring material can withstand the working load of the ball medium. This structure is widely used in low-pressure ball valves.
2. fixed ball pneumatic ball valve
The ball of the stainless steel pneumatic ball valve is fixed and does not move after being pressed. Fixed ball ball valves are equipped with floating seats. After receiving the pressure of the medium, the seats move, so that the sealing ring is pressed tightly on the ball to ensure the seal. Usually, bearings are installed on the upper and lower shafts of the sphere, the operation torque is small, and it is suitable for high pressure and large diameter valves.
In order to reduce the operating torque of pneumatic ball valves and increase the reliability of sealing, oil-sealed ball valves have appeared in recent years. Both special injection of lubricating oil is injected between the sealing surfaces to form a layer of oil film, which enhances the sealing and reduces the operation. Torque is more suitable for high-pressure large-diameter ball valves.
3. elastic ball pneumatic ball valve
The ball of the pneumatic ball valve is elastic. Both the ball and the seat sealing ring are made of metal materials, and the specific pressure of the seal is very large. The pressure of the medium itself can not meet the requirements of the seal, and an external force must be applied. This valve is suitable for high temperature and high pressure media.
An elastic sphere is an elastic groove formed at the lower end of the inner wall of the sphere to obtain elasticity. When closing the channel, the wedge-shaped head of the valve stem is used to expand the ball and compress the valve seat to achieve a seal. Loosen the wedge head before turning the ball, and the ball will return to its original shape, so that there will be a small gap between the ball and the valve seat, which can reduce the friction and operating torque of the sealing surface.
Pneumatic ball valves can be divided into straight-through type, three-way type and right-angle type according to their channel position. The latter two kinds of ball valves are used to distribute the medium and change the flow direction of the medium.