Double seal pneumatic valve can not as to cut off the pneumatic valve with reason

two-seater pneumatic valve pneumatic valve core has the advantage of force balance structure, allow the pressure difference is big, but its disadvantage is that the two seal face not good contact at the same time, cause leakage. If it is used to cut off at artificially, mandatory, obviously the result is bad, even as it made many improvements ( Such as double seal sleeve pneumatic valve) It is not desirable.