Pressure relief valve system

Claim 1

A PRESSURE RELIEF VALVE ASSEMBLY COMPRISING A VALVE BLOCK HAVING AN INLET PASSAGE AND AN OUTLET PASSAGE THEREIN, A PAIR OF VALVE DEVICES MOUNTED ON SAID BLOCK AND COOPERATING THEREWITH TO DEFINE A PAIR OF VALVE CHAMBERS, SAID VALVE BLOCK HAVING A PAIR OF RESTRICTED ORIFICES LEADING FROM SAID INLET PASSAGE RESPECTIVELY TO SAID VALVE CHAMBERS WHEREBY THE VALVE CHAMBERS ARE IN CONSTANT COMMUNICATION WITH SAID INLET PASSAGE, SAID VALVE BLOCK ALSO HAVING A PAIR OF VALVE SEATS FORMED THEREIN, ONE IN EACH VALVE CHAMBER, AND THERE BEING A BORE LEADING FROM EACH VALVE SEAT TO SAID OUTLET PASSAGE, EACH VALVE DEVICE INCLUDING AN ELECTROMAGNETIC COIL AND A MOVABLE ARMATURE, ONE OF SAID ARMATURES BEING SPRING-BIASED TO NORMALLY SEAT DIRECTLY UPON ONE OF SAID VALVE SEATS TO THEREBY NORMALLY BLOCK FLOW FROM ITS ASSOCIATED VALVE CHAMBER THROUGH ITS ASSOCIATED BORE TO SAID OUTLET PASSAGE, A PILOT VALVE INCLUDING A STEM LOOSELY RECEIVED IN THE OTHER BORE AND HAVING AN ENLARGED HEAD SEATED NORMALLY ON THE OTHER VALVE SEAT TO BLOCK FLOW THERETHROUGH, SAID VALVE STEM HAVING AN AXIAL BORE, THE ARMATURE OF THE OTHER VALVE DEVICE BEING NORMALLY SPRING-BIASED TO ENGAGE SAID PILOT VALVE STEM HEAD TO BLOCK FLOW THROUGH SAID AXIAL BORE AND TO SEAT SEAT HEAD UPON ITS ASSOCIATED VALVE SEAT, SAID PILOT VALVE ALSO INCLUDING A PISTON PORTION RECEIVED IN SAID VALVE BLOCK AND FORMING PISTON CHAMBERS ON OPPOSITE SIDES THEREOF, SAID AXIAL BORE COMMUNICATING WITH THAT PISTON CHAMBER BELOW THE PISTON PORTION WHILE THE OTHER PISTON CHAMBER IS COMMUNICATED DIRECTLY WITH SAID OUTLET PASSAGE, SAID PISTON CHAMBER BELOW THE PISTON PORTION ALSO HAVING A RESTRICTED BLEED PASSAGE COMMUNICATING DIRECTLY WITH SAID OUTLET PASSAGE TO DELAY OPENING MOVEMENT AND RETURN MOVEMENT OF THE PILOT VALVE AGAINST THE SEATING ACTION OF THE ARMATURE ASSOCIATED THEREWITH, AND MEANS FOR SELECTIVELY ACTUATING SAID VALVE DEVICES SINGLY AND IN COMBINATION.