Why does a NY400 pad that hasn’t been used in a year start leaking?
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We have several heat exchangers that we bought but never used; it was about a year later before they were installed. When the heat exchanger was first purchased, its seal performance during pressure testing was good, with no leaks. It’s going to be used soon, and during the pressure test after installation, there was leakage at the sealing surface. When opened, the pad is also intact. The gasket uses NY400 oil-resistant asbestos rubber gaskets. What is the reason for this? Has the NY400 oil-resistant asbestos rubber gasket aged? How can we avoid this phenomenon? :(
As a supplementary note, it was the water pressure; the medium used in the heat exchanger is air.
The response wasn’t enthusiastic. Where are the experts?
Although it is not in use, manufacturing stresses and temperature changes can cause uneven tightening of the screws； Asbestos boards lose their elasticity in dry environments, and this is what causes leaks.
Do I need to tighten the screws again? How can asbestos board be made elastic again?
Gaskets don’t age, right? They are placed between the sealing surfaces, and even if they do age, it won’t happen that quickly.
Are you sure it’s an asbestos board pad, and not a graphite high-strength board pad? It can be tightened online; it’s not possible to proceed once it’s loose. If the pad is loosened again, its effectiveness is lost and it needs to be replaced. After tightening it once, pressure testing with air or nitrogen should be carried out to ensure there are no leaks. If it’s impossible to tighten it enough and the pressure test fails, then the pad must be replaced.
This post was last edited by welding on 2015-11-16 at 15:56. It seems that the asbestos rubber gaskets must be used continuously after pressure testing; if there are long periods of inactivity during which the equipment is not used, leaks will occur. So, has anyone paid attention to how long the interval needs to be before there’s no more leakage? One more question: in our case, what is the cause of the leakage in the asbestos rubber gasket?
What are the reasons that cause the oil-resistant asbestos rubber gasket to fail and lead to leaks? I have a question.
If not used for an extended period, the gasket dries out, shrinks, and loses its elasticity, resulting in leaks. It can be tightened online; if that doesn’t work, the only option is to replace it with a new gasket.