The differential pressure gauge indicates a gradual decrease
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The differential pressure gauge shows a gradual decrease in reading. After draining the pressure pipe on site, the reading returns to normal, but no fluid was actually drained; however, once the draining is complete, the reading starts to drop again, and after a few days it reaches 0. This gauge is installed at a height of 50 meters, and it’s very troublesome to read it each time. I would appreciate it if fellow sailors could help analyze what might be causing this issue. Please offer some suggestions – thank you all.
What medium is in the pipeline, and how is the gauge installed? Analysis. . . . . Analyze the air?
It is used to measure the pressure difference in the tower; the gas inside the tower is crude argon! The tower pressure is around 40 KP, and it is divided into a positive pressure guide pipe and a negative pressure guide pipe.
Is there a valve assembly? Is the balance valve leaking?
Tables may drift over time due to prolonged use, so it is recommended to verify them. Check for seal issues under positive and negative pressure
Is there a valve assembly? Is the balance valve leaking? Opinions from the 4th floor of the same building.
Could it be that the pressure lead pipe at one of the positive or negative terminals of the differential pressure gauge is too long? It’s just a guess, though^_^
It’s my fault; there’s a factor I didn’t mention to everyone. The inlets of these two pressure tubes are in a low-temperature environment of around -180 degrees. Yesterday, when I went up to check, I noticed frost forming on the adjacent pressure tubes. It seems that some of the liquid at low temperature inside those pressure tubes hadn’t fully vaporized. At first, only a small amount hadn’t vaporized, but over time more and more liquid accumulated until it blocked the entire pressure tube, causing the pressure difference to gradually drop to 0, or even below 0. However, due to the lower limit of the gauge’s range, it only displayed 0. When the pressure tube was expanded to increase the flow rate, the accumulated liquid at low temperature gradually vaporized, and the pressure tube became unblocked again. Thank you all again! I’m not sure if my guess is correct, after all I’m not an expert in instruments. Please give me some guidance.
The last edit to this post was made by High-Difficulty Instrument Development on 2013-1-1 at 16:42. 1. Hehe, in such low-temperature conditions, using differential pressure can lead to errors due to condensation inside the gas-phase pressure transfer tubes. 2. An alternative approach could be to use a dual-pressure-difference level gauge; both pressure sensing probes should be arranged horizontally, so that whether there is condensation or not, it won’t cause any elevation-related errors. Diagram explanation: 3. Take a photo with your phone and illustrate how it looks in practice for measuring ultra-low-temperature liquid nitrogen tanks
This is about changing the gauge, but that’s not realistic.