News Center
Home > News > News Center

Does the Butterfly Valve Use a Soft Seal or a Hard Seal?

Author: name From: name Modify: Jun. 17, 2020
Jun. 16, 2021

Everyone knows that butterfly valves have soft seals and hard seals. Today, butterfly valve manufacturers will tell you whether butterfly valves are more suitable for soft seals or hard seals. Let's learn about them with Butterfly Valve Supplier.

Soft seal:

The two sides of the seal pair are made of metal materials on one side, and elastic non-metallic materials on the other side, which is called "soft seal". The sealing performance of the seal is good, but it is not resistant to high temperature, easy to wear, and has poor mechanical properties. Such as: rubber; tetrafluoroethylene, etc. The soft sealing seat is made of non-metallic materials and has certain strength, hardness and temperature resistance. The sealing performance is good, and zero leakage can be achieved, but the service life and temperature adaptability are poor.

Hard seal:

The two sides of the sealing pair are made of metal materials or other hard materials, which is called "hard seal". This kind of seal has poor sealing performance, but has good high temperature resistance, wear resistance and mechanical properties. Such as: copper; graphite; alloy steel; (the steel here can also be cast iron, cast steel, alloy steel, or surfacing or spraying alloy).

Butterfly Valve

Butterfly Valve

Hard seals are made of metal and have relatively poor sealing performance, although some manufacturers claim to be able to achieve zero leakage. The soft seal cannot meet the process requirements for some corrosive materials, and the hard seal can solve it! These two types of seals can complement each other. The soft seal is better in terms of sealing, but now the hard seal can also meet the corresponding requirements! The advantage of soft seal is good sealing performance, but the disadvantage is easy aging, wear and short service life. The hard seal has a long service life, but the tightness is worse than the soft seal.

Its structural differences are mainly manifested in:

1. The difference in structure: soft-seal butterfly valves are mostly linear hard-seal, mostly single-eccentric, double-eccentric, and triple-eccentric butterfly valves

2. Temperature resistance: soft sealing in room temperature environment. Hard seal can be used in low temperature, normal temperature, high temperature and other environments

3.Pressure: soft seal low pressure-atmospheric pressure, hard seal can also be used under high pressure and other conditions

4. Sealing performance: The soft sealing and triple eccentric hard sealing butterfly valves have better sealing performance. The triple eccentric butterfly valve can maintain good sealing performance under high pressure and high temperature environment.

Because the butterfly valve has the characteristics of convenient installation, convenient maintenance, simple structure, etc., it replaces gate valves and stop valves in more and more occasions.

Our company also has Butterfly Valve on sale, welcome to contact us.