Pneumatic hard seal butterfly valve refers to both sides of the sealing pair are metal materials or other hard materials are called "hard seal".This seal sealing performance is poor, but high temperature resistance, wear resistance, good mechanical performance, butterfly valve price material benefit.Such as: steel + steel;Steel + copper;Steel + graphite;Steel + alloy steel;(where the steel may also be cast iron, cast steel, alloy steel can also be surfacing welding, spraying alloy).

  Both sides of the pneumatic sealing butterfly valve seal side is the metal material, on the other side is elastic non-metallic materials known as "soft seal".This seal sealing performance is good, but not high temperature resistant, easy to wear and poor machinery.Such as: steel + rubber;Steel + [wiki] four fluorine polyethylene [/ wiki];And so on.Soft seal USES a certain strength, hardness and heat resistance properties of non-metallic materials, sealed performance is good, can achieve zero leakage, but with poor life and adaptability to temperature.
 How the difference between hard sealing butterfly valve with soft sealing butterfly valve:
Hard seal made of metal sealing performance is relatively poor, despite the manufacturers claim to achieve zero leakage.Soft seal part of corrosive material can't meet the technological requirements, hard seal can be solved.The two seal can complement each other, in terms of sealing soft seal is relatively good, but now hard seal sealing also can meet the corresponding requirements.The advantage of soft seal is sealed performance is good, defect is easy ageing, wear and short service life.Hard seal service life is long, but the sealing is relatively worse than soft seal.

Differences between these two kinds of pneumatic butterfly valve structure mainly include the following:

1, the structure of the difference between pneumatic sealing butterfly valve is in the linear more hard seal for more eccentric eccentric single, double and triple eccentric butterfly valve
2, heat resistance, the pneumatic sealing butterfly valve used in normal temperature environment.Hard seal can be used in low temperature, normal temperature and high temperature environment
3, pressure: low - atmospheric pressure pneumatic sealing butterfly valve, hard seal can also be used in high pressure condition, etc
4, the sealing performance of pneumatic sealing butterfly valve and pneumatic hard seal butterfly valve sealing performance is better, the pneumatic sealing butterfly valve in high pressure high temperature environment can keep a good seal.
In view of the above characteristics of pneumatic sealing butterfly valve is suitable for the ventilation and dust removal pipe two-way opening and closing and adjustment, water treatment, light industry, petroleum, chemical industry, etc.Hard seal butterfly valve is used for heating, gas supply, and gas, oil, acid and alkali environment.