Anti-siphon valve

Claim 1

AN ANTI-SIPHON MIXING VALVE FOR CONTROLLING THE FLOW OF LIQUIDS, COMPRISING A VALVE BODY INCLUDING A PAIR OF VALVE SEATS, A PAIR OF INLETS LEADING RESPECTIVELY TO SAID VALVE SEATS, A PAIR OF DIAPHRAGMS SUPPORTED BY SAID VALVE BODY AND ARRANGED TO ENGAGE SAID VALVE SEATS TO SHUT OF THE FLOW FROM SAID INLETS THROUGH SAID VALVE SEATS, SEPARATE PILOT MEANS FOR CONTROLLING THE OPENING AND CLOSING OF EACH OF SAID DIAPHRAGMS ON ITS RESPECTIVE VALVE SEAT, A MIXING CHAMBER FORMED IN SAID VALVE BODY AND RECEIVING THE FLOW FROM BOTH OF SAID VALVE SEATS, AND A DISCHARGE PASSAGEWAY LEADING FROM BOTH SAID MIXING CHAMBER, SAID DISCHARGE PASSAGEWAY INCLUDING A REVERSE BEND SECTION CONNECTED TO SAID VALVE SEAT, AN OUTLET FROM SAID VALVE BODY AND A CURVED SECTION JOINING SAID REVERSE BEND SECTION TO SAID OUTLET, WHEREBY A ROUGHLY S-SHAPED PATH IS FORMED FOR FLUID FLOW BETWEEN SAID MIXING CHAMBER AND SAID OUTLET, A VENT OPENING CONNECTED TO SAID DISCHARGE PASSAGEWAY ADJACENT THE APEX OF SAID REVERSE BEND SECTION AND EXTENDING TO THE SURFACE OF SAID BODY, WHEREBY IF A SUCTION PRESSURE SHOULD OCCUR AT SAID VALVE INLET, AIR IS DRAWN INTO SAID VALVE THROUGH SAID VENT OPENING TO PREVENT REVERSE SIPHONING OF LIQUID OR FOAM FROM SAID OUTLET, SAID VALVE BODY HAVING A TOP, BOTTOM AND BACK SURFACE AND SAID OUTLET AND SAID VENT OPENING EXTEND RESPECTIVELY THROUGH THE BOTTOM AND TOP SURFACES OF SAID VALVE BODY, SAID DIAPHRAGMS AND SAID VALVE SEATS ARE POSITIONED AT OPPOSITE ENDS OF SAID MIXING CHAMBER, SAID INLETS BOTH OPEN THROUGH THE BACK SURFACE OF SAID VALVE BODY TO SAID VALVE SEATS, SAID VALVE BODY INCLUDING A PAIR OF MOLDED PLASTIC PARTS WHICH ARE JOINED TOGETHER TO FORM SAID MIXING CHAMBER AND SAID DISCHARGE PASSAGEWAY, EACH OF SAID PLASTIC PARTS HAVING ONE OF SAID VALVE SEATS FORMED THEREIN.