Based on past experience, experts have identified five common reasons for flange leakage. The first is misalignment, where the pipe is not perpendicular or concentric with the flange, leading to non-parallel flange faces. Flange leakage occurs when the internal pressure exceeds the load pressure of the gasket, usually resulting from installation, construction, or maintenance issues that are easily detectable during inspection at project completion. The second reason is mispositioning, where the pipe and flange are perpendicular but not concentric, causing difficulties in aligning the surrounding bolts with the bolt holes. This may require hole expansion or the use of smaller bolts, reducing tightening force and increasing the risk of leaks due to misaligned sealing surfaces.
The third reason is flange gap, where excessive spacing between flanges can cause gaskets to lose compression force under external loads like axial or bending forces, gradually leading to seal failure. The fourth reason is mis-holing, where the pipe and flange are concentric but the distance between opposing bolt holes on two flanges deviates significantly, generating stress on bolts that can eventually lead to shearing and failure. The fifth reason is stress impact, where changes in temperature and pipe expansion or deformation after medium introduction can subject the flange to bending or shear forces, potentially causing gasket failure.
Therefore, by fully understanding the causes of flange leakage and addressing these five points, improvements can be made in flange processing, usage, maintenance, and related operations to strive for zero leakage.
