Relief valve for use with cryogenic fluids

Claim 1

A RELIEF VALVE FOR USE WITH CRYOGENIC FLUIDS COMPRISING A TUBULAR VALVE BODY OF CIRCULAR CROSS-SECTION HAVING UPSTREAM INLET AND DOWNSTREAM OUTLET ENDS AND AN ANNULAR DOWNSTREAMWARDLY FACING VALVE SEAT LOCATED INWARDLY ADJACENT TO SAID OUTLET END, A POPPET-TYPE MOVABLE VALVE MEMBER MOUNTED FOR AXIAL MOVEMENT IN THE VALVE BODY AND BEING CONSTRUCTED AND ARRANGED TO FIT TIGHTLY AGAINST THE VALVE SEAT OF SAID BODY IN CLOSED POSITION, A THIN CAN-TYPE TENSION MEMBER OF TUBULAR CONSTRUCTION EXTENDING AXIALLY UPSTREAMWARD FROM THE MOVABLE VALVE MEMBER WITH ITS DOWNSTREAM END IN CLOSED CONNECTION TO SAID MEMBER AND ITS UPSTREAM END OPEN TO FLOW OF THE CONDUCTED FLUID STREAM TO IMMERSE INTERNAL WORKING PARTS THEREIN, SAID TENSION MEMBER BEING PROVIDED WITH DIAMETRICALLY OPPOSED LONGITUDINAL SLOTS IN ITS SIDE WALL, A BACKING STRUT EXTENDING LATERALLY THROUGH THE SLOTS IN THE TENSION MEMBER IN SPACED RELATION TO THE ENDS OF SAID SLOTS TO PERMIT AXIAL PLAY THEREIN, THE ENDS OF THE BACKING STRUT BEING ANCHORED IN THE VALVE BODY, STOP MEANS LOCATED AT THE UPSTREAM END OF THE TENSION MEMBER, A HELICAL COMPRESSION SPRING EXTENDING AXIALLY INSIDE THE TENSION MEMBER IN INTERPOSED RELATION TO SAID STOP MEANS AND BACKING STRUT TO RESTRAIN THE MOVABLE VALVE MEMBER AGAINST ITS SEAT, SPRING RATE INITIAL ADJUSTMENT MEANS INCLUDING AN OPEN-ENDED TUBULAR MEMBER ARRANGED COAXIAL WITH RESPECT TO THE TENSION MEMBER AND CONTAINED COMPRESSION SPRING AND BEING OF A DIAMETER TO FIT INSIDE SAID SPRING, THE SAID TUBULAR MEMBER BEING PROVIDED WITH A SEMICIRCULAR HELICAL THREAD IN ITS OUTER PERIPHERY TO ENGAGE DOWNSTREAM END CONVOLUTIONS OF THE COMPRESSION SPRING, WHEREBY THE EFFECTIVE LENGTH OF THE ACTIVE FREELY COMPRESSIBLE PORTION OF SAID SPRING MAY BE PREDETERMINED TO ACHIEVE SPRING RATE ADJUSTMENT, AXIAL THRUST MEANS INTERPOSED BETWEEN THE SAID TUBULAR MEMBER AND THE BACKING STRUT, SAID BACKING STRUT BEING HOLLOW WITH ITS INTERIOR SEALED FROM THE FLOW PATH FOR CRYOGENIC FLUID IN THE VALVE BODY AND CAN-TYPE TENSION MEMBER, AND WHEREIN THE AXIAL THRUST MEANS INCLUDES A TUBULAR BUSHING INTEGRAL WITH SAID STRUT AND HAVING AN AXIAL THROUGH BORE, A HEAD PROJECTING INTO THE INTERIOR OF THE TUBULAR MEMBER OF THE SPRING RATE ADJUSTMENT MEANS AND EXERTING THRUST AGAINST SAID MEMBER, SAID HEAD BEING AXIALLY ADJUSTABLE TOWARD AND AWAY FROM THE TUBULAR BUSHING ON THE BACKING STRUT, AND RELIEF PRESSURE ADJUSTMENT MEANS EXTENDING THROUGH THE INTERIOR OF SAID STRUT AND LATERAL WALL OF THE VALVE BODY AND BEING CONSTRUCTED AND ARRANGED TO PERMIT AXIAL ADJUSTMENT OF SAID HEAD.