The role and use of ball valves
The role of ball valves:
The opening and closing member of a sanitary ball valve is a round sphere with a hole. It uses the 0-90 degree back and forth movement of the ball core rotation around the axis of the valve stem to open or close the valve. Ball valves have many roles. Usually, they are used in pipelines to cut off or adjust medium. Among them, three-way type ball valves can flexibly cut off, distribute and change the flow direction of the medium. The sealing surface of ball valves is usually in a closed status with the sphere surface, so ball valves are not prone to erosion by the medium. And ball valves are easy to operate, have a simple and compact structure, can be used in working conditions where there’s water, natural gas, acid and solvent.
The use of ball valves:
Ball valves, according to the structural type, can be divided into three categories: floating ball valves, fixed ball valves, flexible ball valves. And they, according to sealing performance, can be divided into hard sealing ball valves and soft sealing ball valves. The sealing performance of soft sealing ball valves is better, which can reach zero leakage. Soft sealing ball valves are usually used in pipelines with corrosive medium under normal temperature and pressure while hard sealing ball valves can not only be used in normal temperature and pressure conditions, but also in low temperature and pressure conditions and high temperature and pressure conditions.
The ball body of the floating ball valve is floating, connected and supported by two valve seats. Under the pressure of the medium, the ball body can produce certain displacement and stick close to the sealing surface of the valve seat at the outlet, ensuring the sealing at the outlet. But if the load of the medium sustained by the ball is all passed to the sealing circle at the outlet, under high pressure impact, the ball may be displaced. So this kind of ball valve is usually suitable for normal or low pressure working conditions.
Fixed ball valves, as their name suggests, have a fixed ball body. When the valve is closed, the ball valve won't move even under pressure. Fixed ball valves all have floating valve seats. Under the pressure of the medium, the valve seat moves, tightly pressing the sealing circle onto the ball to ensure sealing. Fixed ball valves are suitable for high pressure or large caliber pipelines.