Fluctuations of the control valve
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The eccentric rotary valve experiences regular fluctuations; a Messonier controller is used for it, and a pneumatic relay is added in between – could you please suggest a solution?
1. The valve positioner is self-tuning; 2. There is a fault with the valve pressure reducing valve, which needs to be replaced; 3. The packing gland is tightened too much – loosen it a bit. These are the only reasons I can think of. We’ll need to analyze the specific issue further
A problem with the valve positioner is highly likely.
We’ve also encountered similar problems with the valves at Meiso; check the entire gas circuit, including the diaphragm head/cylinder section. If that doesn’t work, try replacing the positioner – we’ve replaced it twice
The most likely causes are the locator, so try self-tuning; another possibility is air leakage from the air supply or fluctuations in air pressure – check those as well
Check whether the actuator is leaking air, and check if the pressure relief valve is faulty. If the problem isn’t resolved, add me on WeChat at 26940238; I am from the manufacturer of Mersonilan products
It’s likely the locator is self-tuning; perhaps the linear setting isn’t correct