structure

The sealing performance is good, but the load of the sphere bearing the working medium is all transferred to the outlet sealing ring. Therefore, it is necessary to consider whether the material of the sealing ring can withstand the working load of the sphere medium. When subjected to high pressure shock, the sphere may shift. . This structure is generally used for medium and low pressure ball valves.

The ball of the ball valve is fixed and does not move under pressure. The fixed ball valve has a floating valve seat. After being pressurized by the medium, the valve seat moves, so that the sealing ring is tightly pressed on the ball to ensure the sealing. Bearings are usually installed on the upper and lower shafts with the ball, and the operating torque is small, which 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, the oil-sealed ball valve has appeared, which not only injects special lubricating oil between the sealing surfaces to form an oil film, which not only enhances the sealing performance, but also reduces the operating torque. Suitable for high pressure and large diameter ball valves.

elasticity

The ball of the ball valve is elastic. Both the ball and the valve seat sealing ring are made of metal materials, and the sealing specific pressure is very large. The pressure of the medium itself cannot meet the sealing requirements, and external force must be applied. 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 to obtain elasticity. When closing the channel, use the wedge head of the valve stem to expand the ball and press the valve seat to achieve sealing. Before turning the ball, loosen the wedge head, and the ball will return to its original shape, so that there is a small gap between the ball and the valve seat, which can reduce the friction and operating torque of the sealing surface.