Valve is used to open and close, control, adjust and control the flow of medium parameters (temperature, pressure and flow) of pipeline fittings. According to its function, can be divided into the cut-off valve, check valve, regulating valve, etc.

Valve is the control unit in fluid conveying system, with a cut-off, regulation, guide, to prevent the reverse flow, voltage regulator, the leakage of the shunt or overflow, and other functions. Used for fluid flow control system of the valve, from the most simple cut-off valve to extremely complex automatic control system used in all kinds of valves, its quite a wide varieties and specifications.

The valve can be used to control air, water, steam, all kinds of corrosive medium, mud, oil, liquid metal and radioactive medium, etc. All types of fluid flow. Valve according to the material is divided into iron valves, cast steel valves, stainless steel valves (201, 304, 316, etc.), chrome molybdenum steel valves, molybdenum chrome vanadium steel valve, dual phase steel valves, plastic valves, non-standard custom-made valves, etc. The valve is in the fluid system, is used to control the direction of the fluid, pressure, flow of the device, is to make the piping and equipment within the medium (liquid, gas, powder) flow or stop and can control the flow of the device.

Valve is control unit in the pipeline fluid conveying system, used to change the channel cross-section and flow direction of medium, a diversion, globe, throttle, check, or the overflow pressure relief, and other functions. Used for fluid control valve, from the most simple cut-off valve to extremely complex automatic control system used in all kinds of valves, its breed and specification is various, nominal size of the valve from the tiny instrument valve to size up to 10 m industrial pipe with a valve. Can be used to control water, steam, oil, gas, mud, all kinds of corrosive medium, liquid metal and radioactive fluids such as various types of fluid flow, the valve can work pressure from 0.0013 MPa to 1000 MPa ultrahigh pressure, working temperature can be c - ultra-low temperature of 270 ℃ to 1430 ℃ high temperature.

Valve control can use a variety of transmission way, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic dynamic and electromagnetic hydraulic, electric hydraulic, pneumatic hydraulic, spur gear, bevel gear drive, etc; In pressure, temperature or other form under the action of sensor signals, action, according to the requirement of the reservation or not depend on the sensor signals for simple open or shut down, rely on the drive or automatic mechanism makes opening and closing valve for lifting, sliding, place or rotary movement, so as to change the size of the port in order to realize the control function.