General seal damage causes, it is to seal the job requirements:
1 hardened ( aging) - seals one of the leaking reason is because itself material is temperature hardening, when higher hardness, seal cannot be filled with a gap between the mating parts, can produce leakage.
2 wear - seal wear relates with parts of the surface roughness, velocity and transmission media, different sealing materials to adapt to different velocity.
3 - when the seal extrusion under too much pressure will be extruded onto a metal gap, damage to seal leakage, this relates to seal itself and the hardness of metal clearance is too large, if in the design, selection, processing or the installation of processing is undeserved, can appear extrusion damage.
4 corrosion - show case seal soften even the dissolution, reason is the seal by the media intrusion, selecting a material error. If the media of water or solvent should pay special attention to.
5 general seal according to temperature, speed, pressure and material can be of the following simple classification ( for reference only ):
Temperature rating applicable material speed suitable material pressure rating applicable materials
110 degree C butyronitrile rubber / polyurethane 0.5M/S nitrile rubber 200kg/cm2 with hardness and design
In 200℃fluorine rubber 0.6M/S 400kg/cm2 polyurethane with hardness and design
In 260℃polytetrafluoroethylene PTFE with 14M/S 700kg/cm2 hardness and design
