Control valve moves below mixed operating mode, meeting generation is corroded badly, cavitation, erosive, block card, cut up, sealing surface of exchange part a powerful person can produce serious destruction, cause control valve sealed fluky, sealed life is brief, make domestic control valve a few years not the chronic and stubborn disease of breach. The ponderosity that complete function exceeded light-duty control valve to break through control valve and function are not complete after the problem, we devote oneself to mixed operating mode again sealed difficult breakthrough.
One, the problem that whats is meant by mixed operating mode to reach its to cause
1, high pressure, big press difference -- generation is serious erosive or cavitation, affect sealed life.
2, high temperature, big difference in temperature -- severe heat bilges cold shrink changed what assemble below normal temperature to cooperate property, cause leak, serious when block card up, make an act difficult, even by " card is dead " .
3, sordid medium -- cause serious erosive, block card up, core cut, shadow sound of sth astir is made and sealed.
4, corrode medium -- make contact material to be caused character corrode destroy.
5, Ⅵ level is strong sealed cut off -- press difference to cut off greatly especially, core, must close closely, in the instant that open, sealing surface produces clash and be pulled.
The place on put together narrates: Above the cavitation with mentioned serious generation, erosive, corrode, expand contractive, block the abominable work environment such as card, cut up to fall, Ⅵ level is strong sealed cutting off is extremely difficult more, become domestic control valve a few years to come not the chronic and stubborn disease of breach.
2, analysis of dependability of traditional and sealed structure
1) soft sealed qualitative to soft sealed material soft -- Yi Mi is sealed, extreme difference of because material is qualitative soft dependability.
2) soft sealed to stainless steel -- than (1) slightly good, but sealed still fluky.
3) stainless steel is right stainless steel -- than (2) slightly good, but stainless steel hardness still very low (HRC20 ～ 25) , sealed still fluky.
4) multilayer and sealed valve base -- stainless steel thin plate and weak data jackknife are used, sealed dependability and afore-mentioned (2) (3) about the same, but be able to bear or endure lukewarm function rises somewhat.
5) v wear-resisting alloy -- normally v STELLITE alloy, it is current first-rate is sealed material. But its hardness still not tall (HRC40 ～ 45) , still the slashing condition of incommensurate mixed operating mode.
6) pottery and porcelain is sealed -- hardness is extremely tall, devoid tenacity, easy fragile crack, did not use even crack first.
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