The classification of ball valve
According to the shape to classify
According to the shape, ball valve have O-shaped and V-shaped ball valve. O-shaped ball valve adopts floating structure, ball core is precision castings, chromium plating, seat is enhanced ptfe, pipe diameter is the same with flow pipe mouth, circulation ability greatly, smallest in flow resistance, close no leakage, generally used as switch valve, especially suitable for high viscosity, containing fibres, granular medium V type vall valve USES stationary structure,there is v-type incision on the core, may realize the scale regulating, the flow characteristics is approximate equal percentage.
the classification according to actuators
the classification of valve actuator According to different craft equipment,you can choose pneumatic or electric actuators, forming an pneumatic ball valve and electric valves, pneumatic valves to achieve proportional regulating, valve positioner to be allocated, such as the electric ball valve to be proportionally regulated should choose electric actuators or servo amplifiers, etc.
the classification according to the structure form
First, floating ball valves, body of ball valves are floating, in the medium pressure, ball body can produce certain displacement and adpress the outlet-end seal surface, ensure outlet seal. Floating ball valve is of simple structure, good sealing, but the ball under the working medium to full load on the outlet seal ring, therefore consider whether sealing ring material can withstand sphere of medium work load. This structure, widely used in low-pressure valve.
Second, fixed ball valve, ball spheres is fixed, not moving after pressed. Fixed ball valve seat, with floating by medium pressure, seat sealing tightly to move, the pressure on the ball, to ensure the sealing. Usually, with the sphere containing bearing under shaft, operating torque is small, be applicable to the high pressure and large diameter valve. In order to reduce operating torque and increase the ball valve seal, in recent years, the reliability of the valve seal appeared again, both in the pressure seal lubricants, with the special note form a layer of oil film, which enhances the sealing and reduce operating torque, more applicable high-voltage big caliber ball valves.
Third, the elastic ball valves.The ball valve is flexible. The ball and seat sealing USES metallic materials manufacturing, sealed specific pressure is big, rely on the medium pressure cannot not reached to seal requirements, must exert forces. The valves are suitable for high temperature and high pressure medium.
Elastic ball is that in the lower end of the inner spheres open a flexible and elastic slot to gain elasticity. When closing channel, the use of stem cuneiform head makes the ball body open and press the seat tightly to seal. before the sphere of rotation, loosen the wedge head, the sphere to restore the spheroid and small gaps appears between seat and body, can reduce the friction and operating torque of sealing surface.
the classification according to the passage position
Ball valves can be divided, according to its channels, into three-way type, cut-through type, and right Angle type. the later two valves is for distribution and change the direction of the medium.
