How to check for leaks in a negative pressure system
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I have a set of pressure relief equipment; the pressure remains stable under positive pressure for three days, but it cannot be maintained when under negative pressure. How can I identify the source of the leak? Detergent solution also doesn’t work well under negative pressure
Since it can’t be found, tighten everything and apply silicone sealant
It should be impossible; our vacuum system can maintain a pressure of 0.6 MPa, with the pressure remaining almost constant over 24 hours (the pressure gauge shows little change), and the absolute pressure under negative pressure conditions is only 12 Pa. It works really well
Conduct a vacuum tightness leak test.
My system consists of a 20-cubic-meter tank along with 6 receiving tanks; the large volume makes it difficult to determine the negative pressure
After pressure release, perform a positive pressure test; if isolation is not possible, shut down the system for handling
Spread butter. But personally, it gives me comfort. It’s basically impossible to identify any gaps
Light a candle; if the flame tends to be sucked down, it is approaching the leak point.
It’s quite strange actually – when positive pressure is applied, there’s no leakage at all, so how could there be leakage when negative pressure is used? I have also carried out pressure testing and leak detection on vacuum systems, and I have never seen this phenomenon
During refining, a small amount of air entered, causing the oil to crack at 340 degrees; this reduced the oil’s flash point. That’s why operations were stopped to check for leaks – there were no leaks under positive pressure.
Are there any volatile substances in the material that can evaporate, causing the pressure to rise? Also, is positive pressure maintenance achieved by using a blind flange or valves for isolation? There might be a leak at the valve.