Safety relief valve

Claim 1

A PRESSURE RELIEF VALVE COMPRISING AN APERTURED BODY PORTION HAVING A FRUSTO-CONICAL SEAT THEREIN; BONNET MEANS THREADABLY RECEIVED ON SAID BODY PORTION; SAID BONNET MEANS HAVING WALL MEANS DEFINING A CYLINDRICAL CHAMBER THEREIN HAVING A FIRST PORTION WITH A FIRST DIAMETER ADJACENT SAID SEAT AND A SECOND PORTION WITH A SECOND DIAMETER SMALLER THAN SAID FIRST DIAMETER REMOTE FROM SAID SEAT; PORT MEANS COMMUNICATING WITH SAID CHAMBER; AN APERTURE IN SAID BONNET COAXIAL WITH SAID FIRST AND SECOND PORTIONS; A SLIDABLY MOVABLE VALVE STEM EXTENDING INTO SAID SECOND PORTION THROUGH SAID APERTURE; SAID STEM HAVING SEAL MEANS THEREON REMOTE FROM SAID APERTURE AND IN GUIDED ENGAGEMENT WITH SAID SECOND PORTION; A VALVE DISK RIGIDLY CARRIED BY SAID STEM AND BEING ADAPTED TO COOPERATE WITH SAID FRUTO-CONCIAL SEAT MEANS; SAID VALVE DISK HAVING GROOVE MEANS THEREIN; SEALING MEANS IN SAID GROOVE MEANS ADAPTED TO COOPERATE WITH SAID SEAT THEREBY TO PREVENT FLOW THROUGH SAID BODY PORTION; SAID GROOVE MEANS BEING DEFINED BY FORWARD AND REAR TERMINUS PORTIONS; SAID FORWARD TERMINUS BEING OF LESSER DIAMETER THAN SAID REAR TERMINUS BUT OF A GREATER DIAMETER THAN SAID SECOND PORTION; SAID REAR TERMINUS HAVING A CHAMFERED PORTION THEREON ADAPTED TO ENGAGE SAID FRUSTO-CONICAL SEAT WHEN SAID VALVE IS CLOSED; THE INCLUDED ANGLE OF THE CHAMFER ON SAID REAR TERMINUS BEING GREATER THAN THE INCLUDED ANGLE OF THE FRUSTO-CONCIAL SEAT; SPRING MEANS IN SAID CHAMBER NORMALLY URGING SAID VALVE DISK INTO ENGAGEMENT WITH SAID SEAT; AND MEANS FOR FACILITIATING ADJUSTMENT OF SAID SPRING MEANS TO SET SAID VALVE FOR RELIEF OVER A WIDE RANGE OF PRESSURES.