What is a valve

A valve is a device used in a fluid system to control the direction, pressure, and flow rate of the fluid. It is a device that enables the flow or cessation of the medium (liquid, gas, powder) in the piping and equipment, and can control its flow rate.
A valve is a control component in a pipeline fluid transportation system, used to change the channel cross-section and medium flow direction, and has functions such as diversion, cut-off, throttling, check, diversion, or overflow pressure relief. Valves used for fluid control range from the simplest globe valve to various valves used in extremely complex automatic control systems, with a wide variety of varieties and specifications. The nominal diameter of valves ranges from extremely small instrument valves to industrial pipeline valves with a diameter of up to 10m. It can be used to control the flow of various types of fluids such as water, steam, oil, gas, mud, various corrosive media, liquid metals, and radioactive fluids. The working pressure of the valve can range from 0.0013MPa to 1000MPa at ultra-high pressure, and the working temperature can range from ultra-low temperature of c-270 ℃ to high temperature of 1430 ℃.
The control of valves can adopt various transmission methods, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic 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 predetermined requirements, or simply open or close without relying on the sensing signal. The valve relies on driving or automatic mechanisms to make the opening and closing parts move up and down, slide, swing or rotate, thereby changing the size of its flow channel area to achieve its control function.