Generally, there are four types of gasket leakage: interface leakage, seepage leakage, diffusion leakage and damage leakage.
Interface leakage: leakage will occur on the sealing interface due to insufficient gasket compression, improper flange joint surface finish, flange deformation, etc. For the leakage at the interface, it can be prevented by clamping it in the flange face with soft cushion.
Infiltration and leakage: as the material of soft material is mostly fiber, it is easy to be soaked by medium, especially under pressure. Due to capillarity, the medium will permeate to the low-pressure side, forming infiltration.
Diffusion leakage: under the promotion of concentration difference, the medium passes through the material generated by the seal gap or the capillary tube of the sealing material to cause leakage. Diffusion is the result of molecular motion and is not unidirectional. In case of extremely low sealing pressure difference or vacuum state, or sealing permeable substances such as nitrogen and hydrogen, as well as highly toxic and radioactive substances, special attention shall be paid to the leakage of infiltration and diffusion.
Damage and leakage: the working conditions at the sealing part are relatively bad, with large thermal deformation, frequent vibration and impact, improper installation, excessive fastening force, repeated use, compression deformation, concentrated internal stress, damage beyond the fatigue strength, aging and deterioration of materials, which will cause damage and leakage. This kind of leakage has the greatest impact and great harm, so we should strengthen prevention.