The opening and closing part of the ball valve is a round ball with holes. The ball core is used to rotate 0-90 ° around the axis of the valve rod, so as to open or close the valve. Ball valve has many functions. It is generally used to cut off the switch or adjust the medium in the pipeline. The three-way ball valve can cut off, distribute and change the flow direction of the medium flexibly. The sealing surface of the ball valve is usually closed to the spherical surface, so it is not easy to be eroded by the medium, easy to operate, simple and compact structure, and can be used in the working conditions with water, natural gas, acid, solvent, etc.
Purpose of ball valve:
Ball valve can be divided into floating ball valve, fixed ball valve and elastic ball valve according to the structure. According to the different sealing performance, it can be divided into hard sealing ball valve and soft sealing ball valve. The sealing performance of soft sealing ball valve is better, which can reach zero leakage. It is generally used in normal temperature and atmospheric pressure pipeline with corrosive medium, while hard sealing ball valve can be used not only in normal temperature and atmospheric pressure, but also in low temperature and high temperature and high pressure pipeline.
(1) Floating ball valve
The ball of the floating ball valve is floating and supported by two valve seats. Under the action of medium pressure, the ball can produce a certain displacement and cling to the sealing surface of the valve seat at the outlet end to ensure the sealing at the outlet end. However, if the load of working medium borne by the sphere is all transmitted to the outlet sealing ring, the sphere may shift when impacted by high pressure. Therefore, the ball valve of this structure is generally suitable for normal pressure or low pressure conditions.
(2) Fixed ball valve
The fixed ball valve is so named that the ball is fixed. When the valve is closed, the ball valve will not move even when it is under pressure. Fixed ball valves are equipped with floating seats. Under the pressure of medium, the seats move, making the sealing ring tightly press on the ball to ensure the sealing. Usually, a sliding bearing or rolling bearing is installed on the upper and lower shafts of the ball, which can be operated with small torque and is generally suitable for high pressure and large diameter pipelines.
Other common classifications of ball valves include: ball valve, rail ball valve, v-ball valve, o-ball valve, cut-off ball valve, three-way ball valve, four-way ball valve, forged steel ball valve, ash discharge ball valve, sulfur resistant ball valve, eccentric ball valve, thermal insulation ball valve, pneumatic ball valve, electric ball valve, ferrule ball valve and welded ball valve. Among them, v-ball valve has shear effect, especially suitable for medium containing fiber, small solid particles, slurry, etc. The three-way ball valve can also be divided into T-type and L-type. T-type can make three intersecting pipelines connect or cut off any one of them, playing the role of diversion and confluence. L-type is only connected with two pipes which are perpendicular to each other. It can not connect the third pipe at the same time. It mainly plays the role of distribution.