Reasons for flange seal leakage
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When the system is operating normally, there is no leakage at the flange. So why does leakage occur at the flange seal after the system suddenly stops due to fluctuations and then starts up again after gas is supplied? It’s impossible to tighten it properly. Logically, leakage due to thermal expansion and contraction should allow the fitting to be tightened, so why can’t it be tightened? I hope all fellow sailors will leave active comments
Pressure fluctuations can cause the gaskets between flanges to fail; even if tightened again, this issue cannot be resolved, and the gaskets must be replaced
There are many factors that can cause leaks at flanges, including the quality of the gaskets, uneven forces applied during installation, and the erosion of the gaskets by the materials in contact with them. For gasket materials in critical areas, it is necessary to choose gaskets with high strength that will not suffer from erosion or chemical reactions with the surrounding materials. Since it’s already missing, there’s no need to worry about it; just open it and you’ll see it at a glance.
Specifically, what kind of flange sealing surface and what kind of gasket.
Materials expand when heated and contract when cooled; flanges, bolts, and gaskets are made of different materials, resulting in different coefficients of thermal deformation； Furthermore, after a leak occurs, there may already be debris or crystalline substances at the sealing surface, which can cause the seal to fail.
Does the failure of a gasket mainly occur because it undergoes elastic expansion and is unable to return to its original state?
It is also possible that the bolt has suffered fatigue creep, resulting in a decrease in its strength; both the washer and the bolt need to be replaced
Apart from the material issues related to the components and gaskets themselves； There may also be issues with gasket installation and stress concentration in the pipelines; furthermore, it is possible that there was a minor leak earlier on, one that simply couldn’t be detected ； Disassemble to check the condition, then determine the cause, and continue to monitor! Thank you!
The description of the operating conditions is a bit vague; it would be better to provide a more detailed description. For example, whether the leakage flange is in a high-temperature area, whether the temperature rise or drop is too rapid, what the physical and chemical properties of the medium in the pipeline are, whether it is corrosive or prone to low-temperature crystallization, whether the flange gaskets are of standard size and suitable for use, whether the fasteners are appropriate, whether their material is suitable, and whether the tightening process was done properly – there are many factors involved that require detailed analysis.
The pad is damaged, or the bolts are loose or broken