The function of the seal is to seal the gap between the joint surfaces, isolate or cut off the leak passage, increase the resistance in the leak passage, or add a small work element in the passage to cause pressure on the leak and the pressure difference portion causing the leak. Offset or fully balanced to prevent leakage。     

According to different purposes, the seals are roughly classified according to the following：     

1. Classification by function: divided into shaft seal, hole seal, dust seal, guide ring, fixed seal, rotary seal；     

2. Classification by material: divided into rubber, polyurethane, engineering plastics, etc.。 

Storage:     

1. The storage temperature of the seal is preferably below 30 °C to avoid high temperature aging of the seal；    
2. The seal must be stored in a sealed package to avoid contact with moisture or dust in the air；    

3. The seal must be protected from strong light to prevent the seal from being eroded by the air or prematurely aged。     

The factors affecting the performance of various seals are different. For example, the factors affecting mechanical seals are temperature, medium, wear, and pressure. Common seal name    
Sealing ring, packing, mechanical seal, oil seal, water seal, gas seal, gasket, sealant, soft filler, etc。