Help: Flowserve valves, problems using Siemens positioners
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One of the company’s Fox valves uses Siemens positioners; when set to automatic mode, it fluctuates between around 0 and 3 at low opening degrees – it goes from 0 to 3 repeatedly. When manually投 and controlled by oneself, it works normally. Could it be a problem with the locator? I’ve always believed that if manual operation works fine, then the problem lies with the control system. However, it has been mentioned before that similar issues occurred with other valves using Siemens positioners. After performing auto-tuning, the problem seemed to be resolved for a while, but then it reappeared. Eventually, replacing the positioner solved the issue.
Is there no one? It seems like no one is working on the instruments anymore.
What does the valve look like? This situation occurs if the butterfly valve doesn’t leave the sealing area
What kind of valves are they, and where are they used? Is there any vibration issue with the pipeline?
Flowserve Global valves ensure vibration-free pipelines. It’s been working perfectly all this time
If manual operation works fine, it is recommended to first check for any issues with the signal source. Determine what parameter the automatic mode is linked to, and see whether there are any differences between the set value and the actual value.
1. Consider issues related to the valve itself: check whether there is any external air leakage from the diaphragm and output shaft seals of the valve actuator, and check whether there is any air leakage in the tubing connected via ferrules. 2. Consider the increase in friction coefficient caused by wear of the valve body, valve stem, and valve core, as well as aging of the packing. 3. Siemens’ positioning principle is piezoelectric; no air is introduced once the valve position is reached, and air supply is adjusted when an angle deviation occurs. Is the new locator still from Siemens? It is possible to consider replacing it with a nozzle-type brand locator. 4. Due to different process conditions, flow and temperature control are relatively stable, while pressure control requires frequent adjustments. I hope my years of experience above will be of some help to you.
Thanks, haha. There’s no chance to switch to a different model of locator – it’s very troublesome for the company to change the locator.