Functional use of valve.

Definition

The definition of "valve" is a device used to control the direction, pressure, and flow of fluid in a fluid system. A valve is a device that makes the medium (liquid, gas, powder) in the pipe and equipment flow or stop, and can control its flow.

The valve is a control component in the pipeline fluid transmission system, which is used to change the channel section and the direction of the medium flow, with the functions of diversion, cut-off, regulation, throttling, check, shunt or overflow pressure relief. Valves for fluid control, from the simplest globe valve to the most complex automatic control system used in a variety of valves, its variety and specifications, the nominal diameter of the valve from the very small instrument valve to the diameter of up to 10m industrial pipeline valves. The valve can be used to control the flow of water, steam, oil, gas, mud, various corrosive media, liquid metal and radioactive fluid, etc. The working pressure of the valve can be from 1.3x10mpa to 1000MPa, and the working temperature can be from ultra-low temperature of -269℃ to high temperature of 1430℃. The control of the valve can adopt a variety of transmission methods, such as manual, electric, hydraulic, pneumatic, worm gear, electromagnetic, electromagnetic - hydraulic, electric - hydraulic, gas - hydraulic, spur gear, bevel gear drive, etc. Under the action of pressure, temperature or other forms of sensing signals, according to the predetermined requirements of the action, or do not rely on the sensing signal and simple open or close, the valve depends on the drive or automatic mechanism to make the opening and closing parts for lifting, sliding, swinging or rotating movement, so as to change the size of its flow area to achieve its control function.

Valve application

Valves are widely used in all walks of life and industrial production, and are essential devices for domestic water pipelines and industrial fluid pipelines. Small to the family water pipeline, large to the Three Gorges Dam, Qinshan nuclear power plant, and even the space Shenzhou series spacecraft, the International Space Station have valves in the middle play a vital role. According to data, in the 1 million kilowatt nuclear power plant, the value of the valve accounts for 5% to 10% of the total investment in the nuclear power plant, and the cost of late valve maintenance accounts for 50% of the maintenance cost of the nuclear power plant, which shows the importance of the valve.