What should be used for butterfly valve, soft seal or hard seal?
Soft seal:
Two sides of the sealing pair are metal materials, and the other side is elastic non-metallic material, which is known as "soft seal". The sealing performance of the soft seal for
butterfly valve is good, but it is not resistant to high temperature, and it is easy to abrase and the mechanical properties are poor, such as steel, rubber, PTFE and so on. The soft seal seat is made of nonmetal material with certain strength, hardness and temperature resistance. It has good sealing performance and can achieve zero leakage, but its service life and adaptability to temperature are poor.
Hard seal:
Both sides of the sealing pair are metal materials or other hard materials, which are called "hard seal". The sealing performance of this kind of hard seal is poor, but it has high temperature resistance, wear resistance and the mechanical performance is good, such as steel, steel; steel, copper; steel, graphite; steel, alloy steel; (steel here may also be cast iron, cast steel, alloy steel may also be surfacing, spraying alloy).The hard seal is made of metal, and its sealing performance is relatively poor, although some manufacturers claim that it can achieve zero leakage. Soft seal can not meet the process requirements for some corrosive materials, and hard seal can solve the problem! These two kinds of seals can complement each other. In terms of sealing performance, soft seal is relatively good, but now the sealing performance of hard seal can also meet the corresponding requirements! The advantages of soft seal are good sealing performance, but the disadvantages are easy aging, wear and short service life. The service life of hard seal is long, but its sealing performance is worse than that of soft seal.
