Use elastic sealing material and small actuator thrust to obtain air bubble tight seal, compress the valve seat sealing stress to elastically deform the material and squeeze into the rough surface of the matching metal parts to block all leakage paths. The permeability of the material is the basis for small leakage of the fluid.
Materials that are too soft, or exhibit cold deformation (creep) under load, can be stiffened with fillers such as fiberglass. If it is used to make thin sheets, it can still meet the requirements of use, and can eliminate cold deformation or permanent deformation.
The seal must be carefully secured to prevent rupture and air leakage due to differential pressure. Bonding soft seats to metal parts is one solution, but not a complete solution, as the bond can crack and fail when subjected to thermal shock. A large enough pressure drop will destroy the bonding material.
