Ball valves can be mainly divided into three types according to their structural form: floating ball valves, fixed ball valves and V-type ball valves:
Floating ball valve: The ball is floating. Under the pressure of the medium, the ball can produce a certain displacement and press tightly on the sealing surface of the outlet to ensure the sealing of the outlet. This structure is simple and has good sealing performance, but the load of the working medium borne by the ball is all transmitted to the outlet sealing ring. Therefore, it is necessary to consider whether the sealing ring material can withstand the working load of the ball medium. When subjected to high pressure shock, the ball may deviate. It is generally used for medium and low pressure ball valves.
Fixed ball valve: The ball is fixed and does not move after being pressurized. Fixed ball valves are all equipped with floating valve seats. After being subjected to medium pressure, the valve seat moves, so that the sealing ring is pressed tightly on the ball to ensure sealing. Bearings are usually installed on the upper and lower shafts of the ball. The operating torque is small and it is suitable for high-pressure and large-diameter valves. In order to reduce the operating torque of the ball valve and increase the reliability of the seal, an oil-sealed ball valve has appeared in recent years. That is, a special lubricating oil is injected between the sealing surfaces to form an oil film, which not only enhances the sealing performance but also reduces the operating torque. It is more suitable for high-pressure and large-diameter ball valves.
V-type ball valve: The ball core has a V-shaped structure and has a shearing effect. It is particularly suitable for media containing fibers or tiny solid particles, such as papermaking, chemical industry, metallurgy and other industries. In addition, the V-type ball valve can also achieve more precise flow regulation. Its working principle is to change the relative position of the V-shaped cutout and the pipeline flow channel by rotating the ball, thereby achieving flow regulation. When the ball rotates, the V-shaped cutout gradually opens or closes, and the area of the fluid passing through the cutout changes, thereby achieving flow control.
