Method for placing a protective coating on the interior of a pipe

Claim 1

IN A METHOD FOR RENDERING RESISTANT TO CORROSION THE INTERIOR SURFACE OF A METAL CONDUIT HAVING CORRODED AREAS ON SAID SURFACE THE IMPROVEMENT WHICH COMPRISES: INJECTING INTO ONE END OF SAID CONDUIT AN AMOUNT OF A THERMOSETTING RESIN IN EXCESS OF THAT REQUIRED TO FILL SAID AREAS WITH RESIN, FORCING THE LATTER THROUGH THE LENGTH OF SAID CONDUIT BY MEANS OF A MANDREL OF SUBSTANTIALLY THE SAME DIAMETER AS THE INTERNAL DIAMETER OF SAID CONDUIT, COATING THE INTERIOR OF SAID CONDUIT WITH A FILM OF SAID RESIN, AFFIXING TO ONE END OF SAID CONDUIT A SECTION OF A SECOND CONDUIT HAVING AN OPENING IN THE FRE END THEREOF WHICH IS SMALLER IN DIAMETER THAN THE INTERNAL DIAMETER OF THE FIRST-MENTIONED CONDUIT, PERIPHERALLY CONNECTING A COLLAPSIBLE TUBULAR PLASTIC LINER TO THE OPPOSIET END OF SAID FIRST-MENTIONED CONDUIT, SAID LINER BEING LONGER THAN THE OVERALL LENGTH OF BOTH CONDUITS AND HAVING TIED TO THE FREE END AN ELEMENT CAPABLE OF SEATING IN SAID OPENING, FORCING SAID LINER INTO SAID FIRST-ENTIONED CONDUIT VIA SAID OPPOSITE END BY MEANS OF A PRESSURIZED FLUID WHEREBY SAID LINER IS PLACE INSIDE SAID FIRSTMENTIONED CONDUIT BY TUNING INSIDE OUT, CONTINUING THIS LINING STEP UNTIL SAID ELEMENT SEATS IN SAID OPENING, APPLYING HYDROSTATIC PRESSURE TO THE LINER ADHERING TO TGHE WALLS OF SAID FIRST-MENTIONED CONDUIT, RELEASING SAID PRESSURE, DISCONNECTING SAID CONDUITS FROM ONE ANOTHER, AND REMOVING EXCESS LINER FROM SAID FIRST-MENTIONED CONDUIT.