The control valve starts to regulate on its own
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The following situation was encountered at the production site: an emergency vent valve, with a pressure of 2.0 MPa before the valve; the vent pipe is connected after the valve, and the valve is set to open at a pressure of 2.2 MPa. As a result, it keeps turning on and off by itself; the valve position indicates that it isn’t moving, but there’s still a sound of air being released from time to time! I hope the experienced members of this forum can offer some guidance! The valve is a domestic brand!
It’s haunted! , Stop acting like a fool! Your foreigner is sick. You’re here to cover for those foreign powers and shift the blame; I know the truth. . . . . . :P
An inaccurate adjustment of the valve’s fully closed position, or an incorrect selection of the pressure difference when choosing the valve, can both lead to this issue. If it’s a diaphragm actuator, try increasing the spring preload.
Add a five-second delay check to the program
First, determine whether it is a problem with the DCS system or the valve; otherwise, it’s difficult to make a judgment.
You didn’t explain things very clearly. First, if it’s an electric two-position switch valve, the DCS output goes to the low-voltage electrical distribution panel; you’d better check the electrical system first. The DCS will only open automatically when the pressure is high – it won’t close automatically. Based on what you described, where the valve opens automatically and then closes automatically again, this shouldn’t be a problem with the DCS； Second, if it’s pneumatic, could you first tell me what type of valve it is?
Pneumatic control valve? If the control is fine, there should be fluctuations in the valve; check the positioner and re-tune the control valve.