It is used when vacuum relief is the only requirement. Vacuum relief necessary under working conditions is achieved by a spring or weight loaded pallet. This feature reduces the possibility of tank damage due to an excessive vacuum condition.
Cushioned air seating
Fluoropolymer seating diaphragms minimize sticking caused by resinous vapors and atmospheric moisture.
Self-draining body and drip rings to protect seating surfaces from condensate and freezing
Avoids vacuum buildup due to binding or clogging of the vent