Regarding pneumatic control valves
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I’m hoping some experienced colleague can explain this to me or provide me with some information. Specifically, I need to know how to replace the actuator of a pneumatic control valve, and how to use the feedback rod to determine whether the actuator operates in forward or reverse mode when replacing the valve body. I also want to know how to fix the valve stem properly. The repair technician suggested lowering the valve stem slightly before securing the push rod and the valve stem, so as to ensure that the valve body closes tightly and prevents leakage when there is liquid inside the pipes. I’m a bit confused right now; anyone who can explain this or provide some learning materials, whether in video form or as documents, would be very helpful. Thank you!
Find the manual for the locator; it will contain detailed installation instructions. The installation process varies slightly depending on the manufacturer, with mechanical zero-setting points and range knobs. It operates intelligently by following the instructions. There is no need to worry about the reaction force of the locator; it is sufficient to ensure that the valve position matches that of the DCS.
In mechanical systems, feedback that acts from above is of the positive type, while feedback that acts from below is of the negative type. Try to disassemble it by yourself; be careful with mechanical parts so as not to damage them. If you’re more daring, go ahead and try it
That makes sense, but I guess the original poster can only understand part of it