Valve is a device used to control the direction, pressure and flow of fluid in the fluid system. It is a device to make the medium (liquid, gas, powder) in piping and equipment flow or stop and control its 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 diameter of valves ranges from very small instrument valves to industrial pipeline valves with a diameter of 10 m. It can be used to control the flow of water, steam, oil, gas, mud, corrosive medium, liquid metal and radioactive fluid. The working pressure of the valve can be from 0.0013 MPa to 1000 MPa under ultra-high pressure, and the working temperature can be from c-270 C to 1430 C.
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 achieve its control function.