Gaskets in sealing systems
Gaskets have several important jobs in sealing systems . A gasket must create a seal and hold it over a long period of time. It must be impervious and not contaminate the insulating fluid or gas above the fluid. It should be easily removed and replaced. A gasket must be elastic enough to flow into imperfections on the sealing surfaces. It must withstand high and low temperatures and remain resilient enough to hold the seal, even with joint movement from expansion, contraction, and vibration. It must be resilient enough to avoid taking a “set,” even when exposed for a long time to pressure applied with bolt torque and temperature changes. The gasket must have sufficient strength to resist crushing under applied load and resist blowout under system pressure or vacuum. It must maintain its integrity while being handled or installed. If a gasket fails to meet any of these criteria, a leak will result. Gasket leaks result from improper torque, choosing the wrong type of gasket material, or choosing the wrong size gasket.
Improper sealing surface preparation or the gasket taking a “set” (becoming hard and losing its resilience and elasticity) will also cause a leak. Usually, gaskets take a set as a result of temperature extremes and age.