Classification and sealing principle of plug valves

There are many types of plug valves, and there are multiple classification methods.

1. Divided by structural form: cylindrical plug valve, conical plug valve

2. Classify by sealing surface material

(1) Non metallic sealing material plug valve. The sealing surface material of the plug valve is made of soft materials such as polytetrafluoroethylene, rubber, nylon, para polystyrene, flexible graphite, etc.

(2) Metal sealing material plug valve. The sealing auxiliary material is a plug valve made of metal to metal.

(3) Oil film sealed plug valve. A plug valve that achieves sealing between sealing pairs by pressing sealing grease.

3. Classify by work pressure

(1) Vacuum plug valve. A plug valve with a working pressure lower than the standard atmospheric pressure.

(2) Low pressure plug valve. Plug valves with nominal pressure ≤ 1.6MPa or nominal pressure level% Class150.

(3) Medium pressure plug valve. Plug valves with nominal pressure ranging from 2.5 to 6.4 MPa or nominal pressure class of Class 150-400.

(4) High pressure plug valve. Plug valves with a nominal pressure range of 10.0-80.0Mpa or a nominal pressure level of Class600-2500.

4. Classified by working temperature

(1) High temperature plug valve. t> 450 ℃ plug valve.

(2) Medium temperature plug valve. 120℃

(3) Room temperature plug valve- 40℃

(4) Low temperature plug valve- 100℃

(5) Ultra low temperature plug valve. Plug valve with t ≤ -100 ℃.

5. Classify by connection method

(1) Flange connected plug valve.

(2) Internal thread connection plug valve.

(3) External thread connection plug valve.

(4) Welding connection plug valve.

(5) Clamp connection plug valve.

(6) Card sleeve connected plug valve.

Sealing principle of plug valve

According to the structure and sealing materials of the plug valve, it can be sealed with metal seals, grease seals, and non-metallic soft materials. When using metal sealing, not only lower surface roughness and more accurate shape and position tolerances are required, but also higher sealing pressure is needed to achieve the desired sealing performance. When using grease sealing and non-metallic soft material sealing, more accurate geometric shapes are required. According to the above requirements, there are many structural designs for sealing pairs, and their sealing principles are also different.

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