Classification and general parameters of industrial valves

2020-09-27 14:29:57   

According to the different functions of opening and closing valves, there are many classification methods of valves. Here, the following several kinds are introduced.

 

1. Classification by function and use

 

(1) Block valve: block valve also known as closed-circuit valve, its role is to connect or cut off the medium in the pipeline. Block valves include gate valves, globe valves, plug valves, ball valves, butterfly valves and diaphragms.

 

(2) Check valve: check valve also known as one-way valve or check valve, its role is to prevent the medium flow back in the pipeline. Pump suction off the bottom valve also belongs to the check valve class.

 

(3) Safety valve: the function of safety valve is to prevent the medium pressure in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

 

(4) Regulating valve: control valve includes regulating valve, throttle valve and pressure reducing valve, whose function is to regulate the pressure and flow of medium.

 

(5) Diverter valve: diverter valves include various distribution valves and drain valves, whose function is to distribute, separate or mix the medium in the pipeline.

 

2. Classification by nominal pressure

 

(1) Vacuum valve: refers to the working pressure is lower than the standard atmospheric pressure valve.

 

(2) Low pressure valve: refers to the valve with nominal pressure PN ≤ 1.6Mpa.

 

(3) Medium pressure valve: refers to the valve with nominal pressure PN of 2.5, 4.0 and 6.4 MPa.

 

(4) High pressure valve: refers to the valve whose nominal pressure PN is 10-80mpa.

 

(5) Ultra high pressure valve: refers to the valve with nominal pressure PN ≥ 100MPa.

 

3. Classification by operating temperature

 

(1) < T valve for ultra-low temperature service.

 

(2) Low temperature valve: for medium working temperature - 100 ℃ ≤ t ≤ - 40 ℃.

 

(3) Normal temperature valve: for medium working temperature - 40 ℃ ≤ t ≤ 120 ℃.

 

(4) Medium temperature valve: used for medium working temperature 120 ℃

 

(5) High temperature valve: for medium working temperature T > 450 ℃.

 

4. Classification by driving mode

 

(1) Automatic valve is a valve that does not need external force to drive, but relies on the energy of the medium itself to make the valve act. Such as safety valve, pressure reducing valve, drain valve, check valve, automatic control valve, etc.

 

(2) Power driven valve: power driven valve can be driven by various power sources. Electric valve: valve driven by electric power. Pneumatic valve: valve driven by compressed air. Hydraulic valve: with the help of oil and other liquid pressure driven valve. In addition, there are the combination of the above several driving modes, such as pneumatic electric valve.

 

(3) Manual valve: manual valve with the help of hand wheel, handle, lever, chain wheel, manually operated valve action. When the valve opening and closing torque is large, the wheel or worm gear reducer can be set between the hand wheel and the valve stem. If necessary, the universal joint and transmission shaft can also be used for remote operation.