Relay valve

Claim 1

IN A RELAY, THE COMBINATION COMPRISING A CASING HAVING FIRST AND SECOND COMPARTMENTS IN WHICH SAID FIRST COMPARTMENT IS CONNECTED TO A SOURCE OF SUPPLY PRESSURE AND SAID SECOND COMPARTMENT IS UNDER CONTROL PRESSURE, VALVE SEAT MEANS CONNECTING SAID FIRST AND SECOND COMPARTMETS, VALVE MEANS DISPOSED IN SAID SECOND COMPARTMENT COOPERATING WITH SAID VALVE SEAT MEANS FOR SELECTIVELY CONNECTING SAID FIRST AND SECOND COMPARTMENTS TO PERMIT FLOW THEREBETWEEN, A DIAPHRAGM MEANS MOUNTED IN SAID FIRST COMPARTMENT AND PARTIALLY DEFINING THE SAME FOR SENSING SAID SUPPLY PRESSURE TO GENERATE A FORCE SUBSTANTIALLY EQUAL AND OPPOSITE TO THAT GENERATED BY SAID SUPPLY PRESSURE ON SAID VALVE MEANS, A STEM MEANS MOUNTED WITHIN SAID CASING AND CONNECTED AT ONE END TO SAID VALVE AND CONNECTED TO AND EXTENDING THROUGH SAID DIAPHRAGM MEANS, SAID DIAPHRAGM MEANS SUPPORTING SAID STEM MEANS IN A SPACED, SUBSTANTIALLY COAXIAL, RELATIONSHIP FROM SAID CASING, WHEREBY THE FORCE IMPOSED BY SAID SUPPLY PRESSURE ON SAID VALVE MEANS AND ON SAID DIAPHRAGM MEANS CANCEL EACH OTHER, AND MEANS ON SAID STEM MEANS FOR SENSING SAID CONTROL PRESSURE FOR GENERATING A FORCE EQUAL AND OPPOSITE TO THAT FORCE IMPOSED BY SAID CONTROL PRESSURE ON SAID VALVE MEAN WHEREBY THE FORCES IMPOSED BY SAID CONTROL PRESSURE ON SAID STEM MEANS CANCEL EACH OTHER.