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The difference between pneumatic shut-off valve and pneumatic control valve
Nov 15, 2018

Pneumatic valve is a kind of control equipment driven by compressed air. Because of its high reliability, fast switching speed, intrinsically safe and explosion-proof, it is widely used in gas, steam, liquid and other media without special treatment. Pneumatic valves are equipped with different accessories, which can realize switch and intelligent adjustment of two functions. For these two different control forms of valves, the use of different places, can not be confused.

Pneumatic cut-off valve is mainly used for opening and closing of pipeline medium. The main valve position is opening and closing. It is generally used in positions requiring urgent action. It is common for pipelines to close quickly in case of emergency when they are normally open! uuuuuuuu Pneumatic control valve position is unlimited, matching with positioner, input 4-20 mADC signal and gas source to control operation, and adjust pressure, flow rate, temperature, liquid level and other parameters! 

The difference between pneumatic shut-off valve and pneumatic control valve is:

1. Pneumatic valves include control valves and shut-off valves. Their action forms are different. Although the flow rate of control valves can also be adjusted to 0, shut-off valves are generally used for emergency shut-off. Valve positioners are usually cylinder valves. And the control valve is with pneumatic film, large disc type, in addition to adjustable, but also can be cut off, the only similarity between the two is that they are powered by air.

2. Pneumatic shutoff valves are either fully open or fully closed, mostly for protection; and pneumatic control valves can be switched on and off in any position, can control the valve to stay at a specified opening, can adjust flow or pressure, etc. Pneumatic shut-off valve is used to shut off the medium in the pipeline. It requires fast action, good sealing and leak grade to reach one hundred thousand.

3. Pneumatic control valve is mainly used for continuous regulation control. The signal corresponds to the valve stroke. It is equipped with electrical valve positioner to receive the control model. According to the continuous 4-20MA signal change, the control valve completes 0-100% of the whole stroke action.

4. Pneumatic cut-off valves are only open and closed. They are usually equipped with reversing solenoid valves and stroke switches. Solenoid valves are used to switch the direction of pneumatic actuators, and stroke switches are used to feedback signals to the control system to understand the status of valve position switches in real time. When the pneumatic control valve closes, there may be a certain amount of leakage, while the pneumatic cut-off valve needs zero or approximately zero leakage.