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What is the seal and material of the ball valve?

Views: 273     Author: Site Editor     Publish Time: 2021-09-01      Origin: Site

In the previous article, we introduced the basic knowledge and characteristics of ball valves, but do you know the sealing performance and scope of application of ball valves? Let us find the answer below.



73-1 fixed ball valve,

The tightness of the ball valve

According to different occasions, ball valves can be divided into sanitary ball valves, V-shaped ball valves, eccentric half ball valves, PVC ball valves, etc.



V type ball valve

The flow passage of the V-shaped ball valve is a ball valve with a cut V port, which is a fixed ball valve;

Scope of application: The V port has been specially processed. It is a V-shaped incision. Like a knife, its function is to cut some fibers. For some solid particles, it will be directly crushed. The ball processing method is different. Especially some factories have some sewage or some harder granular media, like this kind of V-shaped ball valve more often


Sealing: The manufacturing process of V-shaped ball valve is usually by surfacing S60 and STL. These two types are collectively referred to as cemented carbide. The seal is directly processed by cemented carbide. The essential material of cemented carbide is 304, and there is another material It is a lo-molybdenum steel, and the ball selected is different according to the temperature resistance.



Sanitary Ball Valve

The manufacturing process of sanitary ball valves is usually welded instead of casting, because the pressure of domestic sanitary ball valves is generally about 6kg, which is relatively thin. Its pipes are welded and the pressure cannot reach. Only the thicker the valve body, its pressure can reach the standard.



Eccentric half ball valve

The eccentric hemispherical valve is similar to the V-shaped ball valve. The valve core is only half, and it is also a fixed ball valve. It is mainly used for solid particles. All solid particle ball valves use eccentric hemispherical valves.


Both the V-shaped ball valve and the eccentric hemispherical valve are unidirectional and can only flow in one direction, not bidirectional flow, because its ball is sealed on one side, and the seal will not be tight when punched by the reverse side, only flowing in one direction. The sealing will be strict only under pressure.


73-2 sanitary ball valves


PVC ball valve

The seals of PVC valves are only EPDM (ethylene propylene diene monomer) and FPM (fluorine rubber)



Hard seal ball valve

The hard seal has a special feature. There is a spring behind the hard seal valve seat, because the hard seal valve seat and the ball cannot rotate if they are directly connected together. The spring is connected behind the valve seat. The ball will stretch during its rotation.



PPL seal

The seal also has a PPL material, its name is enhanced PTFE, the raw material is polytetrafluoroethylene, but some graphite is added to turn it into high temperature resistance, the top temperature can reach 300 °. The normal temperature is 250°, if you need a long time of 300°, you should choose a hard-sealed ball valve.

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