Classification Of Sanitary Ball Valves
The classification of Sanitary Ball Valve is as follows:
1. Fixed ball valve
The ball of the ball valve is fixed and will not move when pressed. The fixed ball valve is equipped with a floating valve seat. After receiving the pressure of the medium, the valve seat moves, thereby pressing the sealing ring tightly against the ball to ensure sealing. The bearings are usually installed on the upper and lower shafts of the sphere, with small operating torque, suitable for high-pressure and large-diameter valves.
In order to reduce the operating torque of the ball valve and improve the reliability of the seal, oil-sealed ball valves have appeared in recent years. Special lubricating oil is injected between the sealing surfaces to form an oil film, thereby improving the sealing performance and reducing the operating torque. , It is more suitable for high-pressure and large-diameter ball valves.
2. Elastic ball valve
The ball of the ball valve is elastic. The ball valve seat sealing ring is made of metal material, and the sealing specific pressure is very large. The pressure of the medium itself cannot meet the sealing requirements, and external force needs to be applied. This valve is suitable for high-temperature and high-pressure media.
The elastic ball is made by opening an elastic groove at the lower end of the inner wall of the ball to obtain elasticity. When closing the channel, use the wedge head of the valve stem to expand the ball and press the valve seat for sealing. Before rotating the ball, loosen the wedge head and the ball will return to its original shape, forming a small gap between the ball and the valve seat, which can reduce the friction and working torque of the sealing surface.
3. Floating ball valve
The ball of the ball valve floats. Under the action of medium pressure, the ball will be displaced and pressed tightly against the sealing surface of the outlet end to ensure that the outlet end is sealed.
The floating ball valve has a simple structure and good sealing performance, but the load of the ball carrying the working medium is all transferred 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. This structure is widely used in medium and low pressure ball valves.
