Pipe coupling

Claim 1

A COUPLER FOR INTERCONNECTING THE ENDS OF PIPES WHICH CARRY GAS OR LIQUID AT TEMPERATURES BELOW -150* F. COMPRISING: (A) A FLANGE ASSEMBLY ADAPTED TO BE SECURED TO THE PIPE ENDS TO BE COUPLED, SAID FLANGE ASSEMBLY INCLUDING AN UPPER FLANGE MEMBER AND A LOWER FLANGE MEMBER, SAID UPPER FLANGE MEMBER INCORPORATING A FIRST, FORCE-TRANSMITTING ANNULAR STEP MEANS IN OPERABLE RELATION WITH A SECOND, FORCE-TRANSMITTING ANNULAR STEP MEANS IN SAID LOWER FLANGE MEMBER, AT LEAST ONE OF SAID ANNULAR STEP MEANS INCORPORATING AN EXTENDED EXTRUSION SPACE PORTION ADAPTED TO RECEIVE EXTRUDED, SEALING MATERIAL THEREIN AND FORCE-TRANSFER MEANS FOR SUBSEQUENTLY APPLYING A COMPRESSION FORCE INITIALLY APPLIED TO COUPLE SAID FLANGE ASSEMBLY TO SAID SEALING MATERIAL; (B) ELASTOMER O-RING MEANS CONSTRAINED IN INITIAL UNCOMPRESSED CONDITION BETWEEN SAID UPPER AND LOWER FLANGE MEMBERS; AND (C) MEANS FOR INITIALLY APPLYING A PREDETERMINED COUPLING FORCE TO SAID FLANGE ASSEMBLY TO MOVE THE UPPER AND LOWER FLANGE MEMBERS INTO A COUPLED POSITION, THE FORCE-TRANSFER MEANS OF SAID ANNULAR STEP MEANS THEREBY MOVING TO A SEAL-ENGAGED POSITION AND BEING DIMENSIONED RELATIVE TO THE COUPLED POSITION OF SAID FLANGE MEMBERS TO THEREBY APPLY A RELATIVELY HIGH COMPRESSION FORCE TO COMPRESS SAID O-RING SEAL INTO A THIN LAYER OF ELASTOMERIC SEALING MATERIAL EXTRUDING INTO THE EXTRUSION SPACE PROVIDED THEREFOR A PREDETERMINED EXTENT SUFFICIENT TO OVERCOME THE INHERENT UNSEATING OF THE SEAL AT CRYOGENIC TEMPERATURES.