Soft-seal and Hard-seal Butterfly Valves Differences and Introductions

ZZJG Valve provides this information on soft-seal and hard-seal butterfly valves main differences and introductions. If you want to know more about soft-seal and hard-seal butterfly valves, please contact us via WhatsApp or email or online chat.

Butterfly Valve Soft Seal Introduction:

A "soft seal" is defined as a sealing pair where one side is a metallic material and the other side is a flexible non-metallic material. This type of seal offers good sealing performance but is not resistant to high temperatures, is prone to wear, and has poor mechanical properties. Examples include: steel + rubber; steel + PTFE + polyethylene, etc. Soft seal butterfly valve seats are made of non-metallic materials with certain strength, hardness, and temperature resistance, offering good sealing performance and potentially achieving zero leakage, but their lifespan and temperature adaptability are relatively poor.

Butterfly Valve Hard Seal Introduction:

A "hard seal" is defined as a sealing pair where both sides are metallic or made of other hard materials. This type of seal offers poor sealing performance but is resistant to high temperatures, wear, and has good mechanical properties. Examples include: steel + steel; steel + copper; steel + graphite; steel + alloy steel (here, steel may also refer to cast iron, cast steel, and alloy steel may be welded or sprayed alloys).

Hard seals are made of metal, resulting in relatively poor sealing performance, although some manufacturers claim to achieve zero leakage. Soft seals cannot meet the process requirements for some corrosive materials, while hard seals can solve this problem! These two types of seals can complement each other. In terms of sealing performance, soft seals are relatively better, but nowadays hard seals can also meet the requirements. The advantage of soft seals is their excellent sealing performance, but their disadvantages include susceptibility to aging and wear, and a shorter service life. Hard seals have a longer service life, but their sealing performance is relatively inferior to soft seals.

The main structural differences in soft seal and hard seal butterfly valve, as follows:

1. Structural differences: Soft-seal butterfly valves are mostly centerline type, while hard-seal butterfly valves are mostly single-eccentric, double-eccentric, or triple-eccentric butterfly valves.

2. Temperature resistance: Soft seals are used in normal temperature environments. Hard seals can be used in low-temperature, normal-temperature, and high-temperature environments.

3. Pressure: Soft seals are used in low-pressure to normal-pressure environments, while hard seals can also be used in medium- and high-pressure conditions.

4. Sealing performance: Soft-seal and triple-eccentric hard-seal butterfly valves have relatively good sealing performance. Triple-eccentric butterfly valves can maintain a good seal under high-pressure and high-temperature environments.

Due to their convenient installation, easy maintenance, and simple structure, butterfly valves are increasingly replacing gate valves and globe valves in various applications.