The ball valve is one of many fluid control valves. The opening and closing member is a circular spherical body with a hole, and the ball is rotated back and forth around the axis of the rod by 0-90° to achieve the purpose of opening or closing the flow.

The function of the ball valve is generally used for switching off and regulating the flow of the medium in the pipeline, and the multi-way ball valve, such as a flanged three-way ball valve, can not only flexibly control the continuous switching of the media merge, split, and flow direction in the pipeline system, but also you can close either channel and make the other two channels work together. The sealing surface of the ball valve is usually in a state of being closed with the spherical surface, so it is not easily eroded. The ball valve has a simple structure and is easy to operate. It can be used in water, oil, natural gas, acid solvent and other working conditions depending on the material.

According to different sealing performance, it is divided into hard sealing ball valve and soft sealing ball valve. The sealing performance of soft sealing ball valve is better, and can reach zero leakage. It is used in normal temperature and pressure pipelines with corrosive media, while hard seal ball valves can be used not only for normal temperature and pressure, but also for low temperature, low pressure and high temperature and high pressure pipelines.

The ball of the trunnion mounted ball valve is mounted, and the ball valve does not move after being pressed. After the medium pressure, the valve seat moves, so that the sealing ring is pressed against the ball to ensure the seal. It is usually equipped with sliding bearings or rolling bearings on the upper and lower shafts of the ball. The operating torque is small and the sealing performance is stable. It is generally suitable for pipelines with high pressure and large diameter.

The ball of the floating ball valve is floating. Under the action of the medium pressure, the ball can generate a certain displacement and press on the sealing surface at the outlet end to ensure the sealing of the outlet end. The floating ball valve has a simple structure and good sealing performance, but the load of the ball subjected to the working medium is all transmitted to the outlet sealing ring, so it is necessary to consider whether the sealing ring material can withstand the working load of the spherical medium, and when subjected to a high pressure shock. The sphere may be offset. Floating ball valve, generally suitable for medium and low pressure piping systems.

The ball of the elastic ball valve is elastic. An elastic groove is formed at the lower end of the inner wall of the ball to obtain elasticity. When the passage is closed, the edge of the valve stem is used to open the ball and press against the seat to seal. Before the ball is rotated, the wedge head is loosened, and the ball is restored to its original shape, so that a small gap occurs between the ball and the valve seat, which can reduce the friction and operating torque of the sealing surface. Generally suitable for high temperature and high pressure media environment.