Pipe joint

Claim 1

A COUPLING COMPRISING A FIRST LENGTH OF TUBING HAVING SCREW THREADS AND A TAPERED PORTION AT ONE END, A SECOND LENGTH OF TUBING HAVING A FLARED END PORTION ENGAGEABLE WITH SAID TAPERED PORTION TO PROVIDE A SLOPING JOINT BETWEEN SAID LENGTHS OF TUBING, MEANS MAINTAINING SAID FLARED END PORTION AND SAID TAPERED PORTION IN CONTACTING RELATIONSHIP, SAID FIRST AND SECOND LENGTHS OF TUBING EACH HAVING AN OUTWARDLY FLARED INNER SURFACE EXTENDING AWAY FROM SAID JOINT, SAID FLARED INNER SURFACES MEETING AT SAID JOINT TO DEFINE AN APEX, A THIN METALLIC EXPANSIBLE SEAL MEMBER POSITIONED IN SAID LENGTHS OF TUBING SPANNING SAID JOINT AND HAVING A WALL THICKNESS LESS THAN THE WALL THICKNESS OF SAID TUBING, SAID SEAL MEMBER BEING CYLINDRICAL WITH A SUBSTANTIALLY CONSTANT INTERNAL AND EXTERNAL DIAMETER PRIOR TO SAID FIRST AND SECOND TUBE MEMBERS BEING IN CONTACTING RELATIONSHIP WITH THE OUTER DIAMETER OF SAID SEAL MEMBER BEING GREATER THAN THE UNFLARED INTERNAL DIAMETER OF SAID TUBING AND LESS THAN THE INTERNAL DIAMETER OF SAID TUBING AT SAID APEX, THE END PORTIONS OF SAID SEAL MEMBER ENGAGING THE OUTWARDLY TAPERED SURFACES OF THE INTERNAL SURFACE ALONG A PORTION OF THE LENGTH THEREOF DUE TO THE DEFORMATION THEREOF WHEN SAID FIRST AND SECOND LENGTHS OF TUBING ARE DRAWN INTO CONTACTING RELATIONSHIP, THE OUTER SURFACE OF THE INTERMEDIATE PORTION OF SAID SEAL MEMBER BEING SPACED FROM THE TAPERED SURFACES ADJACENT SAID APEX WHEREBY SAID INTERMEDIATE PORTION OF SAID SEAL MEMBER CAN EXPAND INTO CONTACT WITH SAID TAPERED SURFACES WHEN SUBJECTED TO INCREASED TEMPERATURES AND PRESSURES.