What Are The Aspects Of Gasket Pre-tightening Stress
Nov 01, 2021
Compared with gasket sealing, it is mainly to prevent flange joint leakage. One of the leakage sources is the penetration and leakage through the seal inside the gasket, and the other key factor is the interface that creates a gap between the gasket and the flange sealing surface. The source of leakage, it can be seen that the leakage of the joint is also critical to the gasket type and material.
1. The gasket can be compressed and deformed to eliminate possible penetration and leakage problems inside the gasket; the greater the compression stress of the gasket, the greater the compression deformation, and the smaller the penetration and leakage of the gasket;
2. The compression deformation of the back up ring fills and blocks the leakage channel caused by the unevenness or surface defects of the flange sealing surface;
3. When the sealing material is hard enough, the sealing contact surface will have enough friction resistance to prevent the back-up ring from moving under fluid pressure;
4. Gasket pre-tightening stress can make up for the reduction of gasket stress caused by fluid pressure, external load, external force, external bending moment, and temperature difference of the piping system under working conditions.
The pre-tightening stress of the gasket is affected by many factors such as gasket creep relaxation, flange deformation, medium pressure and external load, and changes in operating conditions after installation and subsequent use. There are different degrees of reduction, and it is a constant decay process.
In order to ensure safe use, control leakage and make up for installation deficiencies, there should be a sufficiently high gasket pre-tightening stress between the flange sealing surface and the gasket contact surface, which will cause various effects to reduce the gasket stress, and the gasket stress during installation The larger the value, the more beneficial it is to ensure the sealing performance of the bolt flange joint.
For more information about the effect of gasket pre-tightening stress, please contact DSH Seals!
