1. Hard seal: Both sides of the seal pair are made of metal material or other hard materials. It is called hard seal. This seal has poor sealing performance, but it is resistant to high temperature, abrasion and mechanical properties.

2. Soft seal: The side of the seal pair is made of metal material, and the other side is made of elastic non-metallic material called soft seal. This kind of sealing has good sealing performance, but it is not resistant to high temperature, easy to wear and has poor mechanical properties. Soft sealing means that one side of the sealing pair is made of a material with relatively low hardness. Generally speaking, the soft sealing seat has a certain degree. Made of non-metallic materials with strength, hardness and temperature resistance, the sealing performance is good, and zero leakage can be achieved, but the service life and temperature adaptability are relatively poor.

3, the hard seal is made of metal, the sealing performance is relatively poor, although some manufacturers claim to be able to make zero leakage.

4, soft seal for some of the corrosive materials can not meet the process requirements, hard seal can be solved! These two seals can complement each other, and the soft seal is relatively good in terms of sealing, but now the seal of the hard seal can meet the corresponding requirements!

5, the advantage of soft seal is the good sealing performance, the disadvantage is easy to aging, wear, short service life. The hard seal has a long service life, but the seal is relatively inferior to the soft seal.