I hope everyone can help solve this problem
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The situation on site is as follows: The valve is constantly jumping – its stem moves up and down within a small range at a high frequency. However, the pressure readings on the pressure gauge attached to the pressure regulator as well as those on the output side of the positioner remain stable with no fluctuations at all. When the valve is disconnected from the process pipeline, it self-tunes properly and functions normally for valve adjustment; but this phenomenon occurs once the medium starts flowing again
After the valve is cut out, its adjustment is normal, but once it’s installed in the process pipeline, things become strange. Strangely enough, if the valve stem moves up and down, the pressure reading on the gauge at the output end of the actuator should also change
Have you all ever encountered such a situation?
Help, please! I need an expert, ohhhhh
Help, please! I need an expert, ohhhhh
:(Is there really no one at this time?)
I’m so sad, really sad :'(:'(:'(:'(:'(:'(:'(
You have provided too little information. At a minimum: the actual pressure changes before and after the valve, the medium used, temperature, the diameter of the valve seat, the type of valve, the model of the actuator, and the conditions under which oscillation occurs
Check whether the PID tuning of the valve is appropriate It must be this problem!!
What kind of valve? Operating pressure and design pressure, working medium, presence of disturbances, actuator structure, whether there is a diameter change before and after the valve
First, switch to manual control to check whether there is any fluctuation in the valve. If fluctuations occur, it is likely due to factors such as the pressure difference before and after the process pipeline, as well as insufficient stiffness in the valve’s output. In the case of automatic control, the issue lies with the PID parameters