A strange phenomenon related to pressure gauges
Thread Content
The pressure gauge on the outlet pipeline of the pump shows a pressure of 0.7 MPa even when the pump is not turned on, this being due to internal leakage in the pump’s valves. When the valve connecting the pressure gauge to the pipeline is closed, the gauge reading increases as this valve is closed (sometimes the pointer even reverses by one full turn); once the valve is opened again, the gauge reading drops back to 0.7 MPa. The change in the gauge reading is not gradual – each time the valve is moved, the pointer moves accordingly. If the pressure gauge is completely removed, the pointer returns to zero. What’s going on? ? ? Seeking advice! ! Is it a problem with the pressure gauge, or is this just the way things are? Is there a scientific explanation? Waiting online. . .
Remove the pressure gauge, drain and flush the pressure guiding tube to see what the situation is again.
It’s relatively clean, with not many cluttered items
This is a common issue I encounter with pressure relief valves
Have never seen this phenomenon; I also seek an expert’s explanation*
Is it possible that the root valve, due to structural issues, compresses the liquid flowing toward the pressure gauge when it is closed, thereby causing the pressure to rise?
Use a different pressure gauge to conduct the test.
I’m not quite aware of your specific situation; I don’t know what the medium inside the pump is, nor where the pressure gauge at the pump’s outlet is installed, or whether there is a check valve in front of the gauge. If there isn’t such a valve, it’s possible that when the pump stops, negative pressure is created in the pipeline, causing the gauge to show a reading of 0.7. When the shut-off valve is closed, this negative pressure decreases and the gauge pointer returns to zero, giving the impression that the pressure has increased. Personally, I don’t think this situation is very likely to occur, but other than that, I really can’t think of any other reasons. You can go to the site, remove the gauge, and slowly open the root valve to check whether the pipeline is under negative pressure; however, this should not be done in the case of toxic or hazardous substances.
Based on the phenomenon described by the poster, it seems that the valve at the root is located close to the pressure gauge; closing this valve is equivalent to applying pressure to the gauge, thereby increasing its pressure.