Method for preparing lined piping flanged pipe joints

Claim 1

IN A METHOD OF PREPARING FLANGED PIPE JOINTS INCLUDING FLARING THE END OF A PLASTIC LINED METALLIC PIPE WITH THE LINING BONDED THERETO, THE STEPS COMPRISING, LOOSELY PLACING UPON THE METALLIC PIPE A BACK-UP METALLIC FLANGE HAVING AN OPENING THEREIN SUFFICIENT TO RECEIVE THE FLARED END OF SAID PIPE FOLLOWING THE FLARING OPERATION, MOVING A FLARING MEMBER AXIALLY INTO SAID PIPE AND APPLYING THEREWITH A FLARING PRESSURE INTERNALLY OF SAID PIPE AT THE END THEREOF AND FORMING A FLARE UPON THE END OF SAID PIPE WHILE SIMULTANEOUSLY STRESSING THE LINING DURING THE APPLICATION OF SAID PRESSURE WITH COMMENSURATE ESTABLISHMENT OF A RESTORING FORCE IN SAID STRESSED LINING ACTING TO SEPARATE SAID LINING FROM CONTACT WITH SAID METALLIC PIPE MOVING SAID FLANGE INTO ENGAGEMENT WITH THE FLARED END OF SAID PIPE WHILE MAINTAINING SAID LINING IN STRESSED CONDITION, WELDING SAID METALLIC FLANGE TO SAID METALLIC PIPE AND THEREBY HEATING SAID STRESSED LINING AND SIMULTANEOUSLY REDUCING SAID RESTORING FORCE TO A VALUE INSUFFICIENT TO SEPARATE SAID LINING FROM THE FLARED END OF SAID PIPE, PROMPTLY COOLING THE HEATED STRESSED LINING PRIOR TO HEAT DEGRADATION THEREOF, AND THEREAFTER RELIEVING SAID LINING FROM COMPRESSION BY REMOVING SAID FIRST FLARING MEMBER.