What are the causes of wheezing in the output air of a valve positioner?
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At the site, the output gas from one locator caused the control valve stem to move up and down; since it did not affect production, I did not take any action. My general idea is that the issue lies with the line, the safety barrier, the pressure relief valve, the positioner, or the diaphragm; I hope colleagues who have dealt with such faults can share their insights! Thank you!
The approach is good and very clear. Let’s analyze it step by step~
I haven’t dealt with it before, but it’s probably due to the locator
The analysis is quite good; generally, problems occur in these areas: leakage in the actuators or obstruction in the gas supply lines, leakage in the gas supply lines connected to the diaphragm heads, jamming of the valves themselves, and pipe vibration, among others.
It’s about the locator issue; however, sometimes replacing the locator doesn’t work either. For electrical locators, loosening the air nozzle on the cover can solve the problem, but it’s a bit more complicated with smart locators – just adjust it gradually
The last edit to this post was made by ZZDDKK on 2016-4-26 at 08:27. In such cases, it also depends on the brand of the locator. 1. Perform a self-check on the locator to see if it functions properly after that check. No, use a different locator. 2. Turn off the tightening function of the locator; for example, in Siemens systems. 3. It is possible to reset the PDI parameters of the valve. For Fisher models 6010 and 6020, increase the proportioning value and reduce the integration value to see what happens. Like with other positioners: 4. Check the piezoelectric element and the amplifier; these components have failed before, so replacing them with new ones will solve the problem. 5. The screws holding the feedback rod may be loose, or the feedback rod itself may be damaged or uneven. 6. Disassemble the valve to check the condition of the spring diaphragm. 7. Basic tests such as checking for air leaks are carried out at the beginning, so they won’t be discussed in detail here. Our valves have experienced surging issues, and the cause has never been identified; you can try the methods mentioned above – I hope it will be helpful to you
If the control system is fine, it might be that the gain of the valve positioner is too high, or the control valve is stuck.
The problem with the locator is serious; it might be a fault in the magnifying component of the locator. Both the intelligent and mechanical versions can be replaced separately
I’ve encountered the same problem as well; it was an issue with my locator amplifier. I suggest trying to use one from another locator. Can we rule things out step by step first?