Structure of ball valve

Structure of ball valve
The opening and closing part of the ball valve is a ball with a circular channel, which rotates around the axis perpendicular to the channel, and the ball rotates with the valve stem, so as to achieve the purpose of opening and closing the channel. The ball valve can be closed tightly with 90 degree rotation and small torque. According to the actual working condition data needs, the driving technology devices with different assembly methods can form ball valves with various forms and different enterprise control research methods, such as electric ball valve, pneumatic ball valve, hydraulic ball valve and so on.
According to the structure, it can be divided into three parts
1、 Floating ball valve
The ball valve floats under the medium pressure, which can produce a certain displacement of the ball and the extrusion end, so as to ensure the sealing surface of the outlet end of the seal.
The floating ball valve has simple structure and good sealing performance, but the ball bears the load of the medium in the social work environment, and all the information is transmitted to the export seal ring. Therefore, it is necessary to consider whether the seal ring material enterprise can withstand the actual load of the sphere medium. This kind of economic structure is widely used in medium and low pressure ball valves.
2、 Fixed ball valve
The ball valve is fixed and does not move after compression. The fixed ball valve is equipped with floating valve seat. After medium pressure, the valve seat moves to make the sealing ring close to the ball to ensure the sealing. The ball is usually used on the upper and lower bearings with small operating torque distance, which is suitable for high-pressure large-diameter valves.
In order to reduce the operating torque of ball valve and improve the effectiveness of sealing, a kind of oil sealed ball valve has appeared in recent years. It not only injects special lubricating oil between the sealing surfaces to form a layer of oil film, which improves the sealing performance and reduces the operating torque, but also is more suitable for high-pressure large diameter ball valve.
3、 Elastic ball valve
The ball valve is flexible. And a ball valve seat ring is made of metal material according to the requirement that the pressure medium itself has reached less than the sealing element, and the large ratio of sealing pressure, and the external force must be applied. Such valves are designed for high temperature and high pressure platforms.
Elastic analysis sphere is to open an elastic groove at the lower end of the inner wall of the sphere to obtain psychological elasticity. When a channel is closed, the wedge head of the valve stem is used to make the ball expand and compress the valve seat to improve the sealing. Before turning the ball, loosen the wedge head first, and then the ball will return to its original shape, so that there is no small gap between the ball and the valve seat, which can reduce the trade friction on the working face of the mechanical seal and the torque in the operation process.