Detailed classification of valves and main parameters

Valve is a device used by Gongliang to control the direction, pressure and flow of fluid in fluid system. Valves are devices that allow or stop the flow of media (liquids, gases, powders) in piping and equipment and control their flow.

Valve is the control part of pipeline fluid delivery system. It is used to change the channel section and the direction of medium flow. It has the functions of diversion, cut-off, throttling, check, diversion or overflow pressure relief. Valves for fluid control range from the simplest cut-off valves to various valves used in extremely complex automatic control systems. The nominal size of valves ranges from very small instrument valves to industrial pipeline valves with a diameter of 10 m. Valves can be used to control the flow of water, steam, oil, gas, mud, corrosive media, liquid metal and radioactive fluids and other types of fluids. The working pressure of valves can be from 0.0013 MPa to 1000 MPa under ultra-high pressure, and the working temperature can be from - 270 C to 1430 C under ultra-low temperature. Valve control can adopt a variety of transmission modes, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electro-hydraulic, electro-hydraulic, pneumatic, spur gear, bevel gear drive, etc. Under the action of pressure, temperature or other forms of sensing signals, the valve can act according to the predetermined requirements or simply open or close without relying on sensing signals, and the valve relies on it. The driving or automatic mechanism makes the hoist move up and down, slip, swing or turn, thus changing the size of its runner area to realize its control function.

According to function and use

1) Truncation type: such as gate valve, globe valve, cock valve, ball valve, butterfly valve, needle valve, diaphragm valve, etc. Cut-off valves, also known as closed-circuit valves, globe valves, their role is to connect or cut off the medium in the pipeline.

Check valve, also known as one-way valve or check valve, is an automatic valve. Its function is to prevent medium backflow in pipeline, reverse pump and drive motor, and leakage of container medium. The bottom valve of pump suction closure also belongs to check valve type.

Explosion-proof valves, accident valves, etc. The function of safety valves is to prevent the medium pressure in pipes or devices from exceeding the prescribed value, so as to achieve the purpose of safety protection.

Regulating valves, throttle valves and pressure relief valves are used to regulate the pressure and flow rate of medium.

2) Vacuum type: such as vacuum ball valve, vacuum baffle valve, vacuum inflation valve, pneumatic vacuum valve, etc. Its function is to change the direction of air flow, adjust the size of air flow, cut off or put through the pipeline of the vacuum system components called vacuum valves.

3) Special uses: such as pigging valves, vent valves, sewage valves, exhaust valves, filters, etc. Exhaust valve is an essential auxiliary component in pipeline system, which is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. Often installed at the elevation point or elbow, to eliminate excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption.

According to the main parameters

Nominal pressure

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

2) Low pressure valve: refers to the valve whose nominal pressure PN is less than 1.6 Mpa.

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

4) High pressure valve: refers to the valve with nominal pressure PN of 10.0 Mpa to 80.0 Mpa.

5) Ultra-high pressure valve: refers to the valve with nominal pressure PN (> 100.0 Mpa).

6) Filter: refers to nominal pressure PN 1.0 Mpa, 1.6 Mpa

According to working temperature

1) Ultra-low temperature valve: Valve for medium working temperature t<-101 ~C.

2) Normal Temperature Valve: Valve for medium working temperature - 29 < T < 120 ~C.

3) Medium Temperature Valve: Valve for medium working temperature 120 (< T < 425 (?)

4) High temperature valve: valve for medium working temperature T > 425 C.