The valve is in a fluid system for controlling the direction of the fluid, the pressure device, is to make the flow pipe and the medium inside the device (liquid, gas, powder) or stopped flow apparatus and its flow control.

Pipeline valves are controlled fluid delivery system components, which is used to change the channel section and flow direction of medium, with diversion, off, throttling, non-return, diversion or overflow relief functions. For fluid control valves, valves off from the most simple to the most complex automatic control valve used in the system, and its many varieties and specifications, the valve nominal diameter from large to tiny instrument valve diameter up to 10m industrial pipeline valves. EHV can be used to control the water, steam, oil, gas, mud, corrosive media, liquid metals and radioactive fluids and other types of fluid flow, the valve working pressure from 0.0013MPa to 1000MPa, the working temperature from 1430 ℃ ultra-low temperature to a high temperature of -270 ℃ of.

Control valve can be a variety of drive, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic move, electromagnetic hydraulic, electro hydraulic, pneumatic and hydraulic, spur gears, bevel gear drive and the like; in pressure, temperature or the role of other forms of sensor signals, according to the requirements prescribed action, or do not rely on the sensor signal and a simple on or off, the valve is being driven or automatic mechanism to open and close member for lifting, sliding, rotating or rotary pendulum movement, thus changing the size of its flow area to achieve its control function.