Safety device for use in testing relief

Claim 1

IN A SAFETY DEVICE FOR TESTING A RELIEF VALVE ON A FLUIDCONTAINING VESSEL COMPRISING A HOUSING ADAPTED TO FORM A SEALED ATTACHMENT AROUNG A RELIEF VALVE; A COUPLING ROD EXTENDING THRU SAID HOUSING FROM THE ATTACHING END THERE OF HAVING MEANS ADJACENT SAID END OF ATTACHING TO THE HEAD OF SAID RELIEF VALVE; MEANS IN THE END OF SAID HOUSING OPPOSITE THE ATTACHING END FOR SEALING SAID HOUSING WITH SAID COUPLING ROD COMPRISING AN INWARDLY FACING VALVE SEAT IN THE OPPOSITE END OF SAID HOUSING SURROUNDIN SAID ROD AND A VALVE HEAD ON SAID ROD INSIDE SAID HOUSING ADAPTED TO SEAT IN SAID VALVE SEAT ON AXIAL MOVEMENT OF SAID ROD AWAY FROM SAID RELIEF VALVE; AND A VALVE IN THE SIDE OF SAID HOUSING FOR CONTROLLING FLUID FLOW THEREFROM, THE IMPROVEMENT COMPRISING A FIRST ANNULAR SECTION ON THE VALVE HEAD ON SAID ROD EXTENDING AWAY FROM SAID RELIEF VALVE; A SECOND ANNULAR SECTION ON SAID VALVE SEAT CONCENTRICALLY SURROUNDING SAID FIRST ANNULAR SECTION; AND SLIDABLE SEALING MEANS BETWEEN SAID FIRST AND SECOND ANNULAR SECTIONS ADAPTED TO MAINTAIN A FLUID TIGHT SEAL UPON LIMITED LONGITUDINAL MOVEMENT OF SAID COUPLING ROD.