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What is the difference between a soft seal and a hard seal of a butterfly valve?

Posted by Bundor valve
In recent years, butterfly valves have been widely used in more and more places because of their convenient installation, convenient maintenance, and simple structure.Bundor Valve's ace product is butterfly valve. The high-quality butterfly valve produced by it has won praise from many new and old customers.
Butterfly valves have hard and soft seals. What is the difference between them?
First introduce the hard seal butterfly valve.Butterfly valve hard seal means that both sides of the sealing pair are made of metallic materials or other hard materials. The sealing performance of this seal is poor, but it is resistant to high temperature, wear and mechanical properties.Such as: steel + steel; steel + copper; steel + graphite; steel + alloy steel.

Then introduce the soft seal butterfly valve.Butterfly valve soft seal means that the two sides of the seal pair are made of metal material and the other side is made of elastic non-metal material.This seal has better sealing performance, but is not resistant to high temperature, easy to wear, and has poor mechanical properties. Such as: steel + rubber; Steel + PTFE.
The differences in their structure are mainly as follows:
1. Structural difference
Soft seal butterfly valves are mostly centerline type, and hard seals are mostly single eccentric, double eccentric and triple eccentric butterfly valves. 
2.Temperature resistance
Soft seals are used at room temperature. Hard seal can be used in low temperature, normal temperature, high temperature and other environments.
Soft seal low pressure-normal pressure, hard seal can also be used in medium and high pressure conditions.
4.Sealing performance
Soft seal and triple eccentric hard seal butterfly valve have better sealing performance. Triple eccentric butterfly valve can maintain good seal under high pressure and high temperature environment.
Electric soft-sealed butterfly valves, pneumatic soft-sealed butterfly valves, and hard-sealed butterfly valves have started to replace electric gate valves and globe valves in more and more occasions. Bundor Valve has 25 years of experience in the valve industry. The sales volume keeps rising and has been well received by many new and old customers. Purchasing a good butterfly valve can reduce a lot of extra investment, it is better to know the butterfly valve of Bender valve before making a decision!