The hard seal butterfly valve is a so-called "hard seal" in which both sides of the seal are metal materials or other hard materials. Butterfly valve hard seal sealing performance is poor, but high temperature, anti-wear, good mechanical properties. Such as: steel + steel; steel + copper; steel + graphite; steel + alloy steel; (where the steel may also be cast iron, cast steel Alloy steel may also be surfacing, sprayed alloys).

Soft-seal butterfly valve: The side of the seal is made of metal material on one side and the non-metallic material on the other side is called “soft seal.” This seal has good sealing performance, but it is not high-temperature resistant and easy to wear. Poor mechanicality. Such as: steel + rubber; steel + PTFE; soft seal seat with a certain strength, hardness and temperature performance of non-metallic materials, sealing performance, can be made to zero leakage, but the life and adaptability to temperature Relatively poor. Hard seals are made of metal and the sealing performance is relatively poor, despite the fact that valve manufacturers claim to be zero-leakage. Soft seals on some of the corrosive materials can not meet the process requirements, hard-seal disc valve can be solved! These two kinds of seals can complement each other, and soft seals are relatively good in terms of sealability, but now the sealability of hard seals can also meet the corresponding requirements! The advantage of a soft-seal disc valve is its good sealing performance. The disadvantage is that it is prone to aging, wear, and short service life. Hard-sealed disc valves have a long service life, but their sealing performance is lower than that of soft-seal butterfly valves.

The structural difference between two:

1. Structural difference:

Soft seal butterfly valve is mostly center line butterfly valve,

Hard seal is mostly single eccentric, double eccentric, triple eccentric butterfly valve;

2, temperature:

Soft seal for normal temperature environment.

Hard seal can be used in low temperature, room temperature, high temperature and other environments;

3, pressure:

Soft seal low pressure - normal pressure,

Hard seal can also be used in medium and high pressure and other conditions;

4, sealing performance:

soft seal butterfly valve and three eccentric

hard seal butterfly valve sealing performance is better, three eccentric butterfly valve in a high pressure and high temperature environment can maintain a good seal.

In view of the above characteristics, the soft seal butterfly valve is suitable for the bidirectional opening, closing and adjustment of ventilation and dust removal pipelines, water treatment, light industry, petroleum and chemical industries. Hard seal butterfly valves are used in heating, air supply, gas, oil, acid and alkali environments.

With the wide use of butterfly valves, the features of easy installation, convenient maintenance and simple structure are obvious. Electric soft-seal butterfly valves, pneumatic soft-seal butterfly valves, and hard-seal butterfly valves have begun to replace electric gate valves and globe valves in more and more applications.