Floating ball valve structure classification

Floating ball valve

The ball valve ball 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 that the outlet end is sealed.

The floating ball valve is simple in structure and has good sealing performance. However, the ball bears the load of working medium and all the load of working medium is transferred to the outlet seal ring. This structure is widely used in low and middle pressure ball valves.

Fixed ball valve

The ball of the floating ball valve is fixed and does not move under pressure. Fixed ball valve with floating seat, after the medium pressure, the seat moves, so that the sealing ring tightly pressed on the ball to ensure the sealing. Bearings are usually mounted on the upper and lower shafts of the ball with small operating torque for high pressure and large bore valves.

In order to reduce the operating torque of ball valve and increase the reliability of sealing, oil seal ball valve has appeared in recent years. It can not only fill special lubricating oil between the sealing cover to form a layer of oil film, which not only enhances the sealing performance, but also reduces the operating torque. It is more suitable for high pressure and large caliber ball valve.

Elastic ball valve

The ball of the ball valve is elastic. The ball and seat seal ring are made of metal material, and the sealing pressure is very high. The pressure of the medium itself cannot meet the requirements of sealing, so 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. When closing the channel, use the wedge of the stem to make the ball open and the seat tight to seal. Before rotating 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 seat, which can reduce the friction and operating torque of the sealing surface.

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