Sealing butterfly valve with hard seal butterfly valve and use of the distinction

Valve seal means sealing the sides are rigid metallic material or other materials are called "hard seal ." This seal sealing performance is poor, but high temperature, abrasion resistance, good mechanical properties , such as : steel + steel ; steel + copper ; steel + graphite ; steel + alloy ; ( where steel may be cast iron, cast steel, alloy steel may be surfacing , spraying the alloy ) .
Soft sealing : sealing the sides of the metal material side , the other side there is a flexible non-metallic materials are called "soft seal ." This seal sealing performance is good, but not high temperature, easy to wear, mechanical poor , such as: steel + rubber ; steel + PTFE [wiki] polyethylene [/ wiki]; etc. soft sealing seat using a certain strength , hardness and heat resistance of non-metallic materials, good sealing performance, zero leakage can be done , but the life and relatively poor adaptability to temperature . Hard sealed with metal production, sealing performance is relatively poor , despite the manufacturers claim can be done zero leakage. Soft seal on the part of corrosive materials can not meet the technical requirements , the seal can be solved ! These two seals can complement each other , just in terms of soft seal tightness is relatively good , but now it is possible to seal tightness meet the corresponding requirements ! soft seal the advantage of good sealing performance , the disadvantage is easy to aging , wear, short life. Seal long life, but the relative tightness worse than the soft seal .
Their structural differences are mainly the following:
1, the structural differences : soft seal butterfly mostly in line more than a single eccentric hard sealing , double eccentric butterfly valve
2 , temperature : soft plastic seal for normal environments. Seal can be used for low temperature , room temperature , high temperature and other environmental
3 , pressure: soft sealing pressure - atmospheric pressure seal can also be used in high-pressure and other conditions
4 , the sealing performance: soft cargo seal and three eccentric hard sealing butterfly valve sealing performance is better, three eccentric butterfly valve in the high pressure high temperature environment can maintain a good seal.
In view of the above characteristics, soft seal butterfly valve for opening and closing the ventilation and dust piping bidirectional adjustment, water , light industry, petroleum, chemical and other industries. Hard seal butterfly valve used for heating, gas , and coal gas , oil, acid and alkali environment .
With the widespread use of butterfly valves , its easy installation, easy maintenance , simple structure features becoming increasingly apparent. Electric soft seal butterfly valve, pneumatic soft seal butterfly valve, hard seal butterfly valve in more and more places began to replace the electric gate valve, globe valve.