Instrument Quiz of the Day, 2016.6.21

Is there any air leakage in the actuator, is the diaphragm damaged, and is it an intelligent locator?

Is it electric or pneumatic? The valve operates without a pressure difference; in my opinion, this could be due to the valve itself (excessive sensitivity in electric valves, leaks in the diaphragms of pneumatic valves, etc.), the positioner (fluctuations in the output from the positioner, etc.), or unstable adjustment output signals, etc.

Pneumatic, intelligent locator, diaphragm head with no air leakage

My current assessment is that, first, the packing is tight; Panasonic’s packing provides very good results. Second, there is an issue with the guidance mechanism and the valve stem

Check for any air leaks from the locator to the cylinder; if there are no such leaks and the parameters of the locator are fine, in the case of an intelligent locator, it is possible to make observations by appropriately modifying the p value

Is it in the open or closed position? Check the zero position of the valve actuator

The reasons for valve surging are mainly as follows: 1. As mentioned by the original poster, a clogged actuator can be resolved by loosening the gland slightly, which can yield good results. 2. There is no retaining ring on the feedback rod; it moves freely, and a retaining ring needs to be installed. Or replace the feedback rod. 3. The internal membrane of the electronic locator is damaged, resulting in air leakage. (Internal air leakage) It is necessary to open the diaphragm head on top of the locator to check for leaks. 4. Self-tuning was not performed, resulting in issues with internal calculations. 5. The pressure relief valve is faulty, resulting in fluctuations in the output air supply. That’s what I’ve seen; there might be other reasons as well. The failure rate of electronic locators is generally low, so I haven’t encountered any other causes yet.