Relief valve

Claim 1

A RELIEF VALVE COMPRISING AN ELONGATED THIN-WALLED TUBULAR STEM INCLUDING A MAIN SECTION AND A HIGH PRESSURE END SECTION OF REDUCED RADIUS INTEGRAL THEREWITH, AN ANGULAR PERIPHERAL SHOULDER AT THE JUNCTION OF THE TWO SECTIONS, AN ANNULAR TROUGH MEMBER ON SAID END SECTION HAVING AN AXIALLY INWARDLY TURNED LIP THEREON, A SLEEVE HAVING AN OUTWARDLY FLARED LIP AT ONE END THEREOF DISPOSED IN SAID END SECTION IN CLOSE FITTING RELATIONSHIP THEREWITH, WITH ITS SAID FLARED LIP ENGAGING SAID SHOULDER AND ITS OTHER END EXTENDING INTO SAID END SECTION TO A POINT ADJACENT THE INNER END OF THE LIP ON SAID TROUGH MEMBER, A CYLINDRICAL VALVE PLUNGER SLIDEABLE AXIALLY IN SAID SLEEVE AND HAVING A FACE DISPOSED TOWARD SAID TROUGH MEMBER, AN O RING FILLING SAID TROUGH MEMBER AND HAVING A PORTION EXTENDING BEYOND SAID LIP THEREON, SAID SLEEVE ENGAGING SAID O RING AND HOLDING IT IN SAID TROUGH HELICAL SPRING MEANS IN SAID STEM FOR URGING SAID PLUNGER IN SEALING ENGAGEMENT AT A PREDETERMINED PRESSURE WITH SAID O RING, AN INDENTATION FORMED INTEGRALLY WITHIN SAID STEM FOR CAPTURING SAID SPRING MEANS WITHIN SAID STEM, SAID PLUNGER HAVING AN OUTSIDE DIAMETER GREATER THAN THE MEAN DIAMETER OF SAID O RING AND BEING CONSTRUCTED AND ARRANGED SO THAT SAID O RING IS COMPRESSED BY SAID FACE OF SAID PLUNGER TO PROVIDE A SEALING SURFACE INCLUDING AN INWARDLY EXTENDING PORTION THEREOF ENGAGED BETWEEN SAID FACE AND SAID LIP ON SAID TROUGH.