Method for lining a pipe or main

Abstract

A method for lining a pipe or main comprising heating a length of synthetic-resin liner pipe 20 of external diameter substantially equal to or greater than the internal diameter of the pipe or main 40 to be lined, mechanically deforming the heated liner pipe 20 to reduce its external diameter to less than the internal diameter of the pipe or main 40 to be lined, causing the liner pipe 20 to enter the pipe or main 40 to be lined and pressurizing the internal wall of the liner pipe 20 to cause it to expand into engagement with the internal wall of the pipe or main 40 to be lined.

I claim: .[.1. A method of lining an underground pipe or main, said method comprising the steps of: 
     
        of a cable attached to the leading edge of the liner pipe..]..[.6.  A method as claimed in claim 5 in which the cable is wound onto the drum of a motorized winch to draw the liner pipe into the underground pipe or main to be lined..]..[.7. A method as claimed in claim 1 in which a succession of lengths of synthetic-resin pipe are butt-welded together to obtain the 
     
     
        liner pipe..]..[.8.  A method as claimed in claim 1 in which the internal wall of the liner pipe is pressurized at superatmospheric pressure..]..[.9. A method as claimed in claim 8 in which the internal wall of the liner pipe is pressurized with air..]..[.10. A method as claimed in claim 1 in which both ends of the liner pipe are closed with closures to enable the internal wall of the liner pipe to be pressurized..]..[.11. A method as claimed in claim 1 in which the 
     
     
        synthetic-resin is polyethylene..]..Iadd.12.  A method of lining an underground pipe or underground main, said method comprising the steps of: (a) preheating a continuous length of synthetic-resin liner pipe of external diameter substantially equal to or greater than the internal diameter of the underground pipe or underground main to be lined to a temperature of about 100° C.;   (b) drawing the so-heated continuous length of liner pipe into the underground pipe or underground main to be lined through at least one swaging die dimensioned to reduce the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined;   (c) reducing the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined; and   (d) pressurizing the internal wall of the continuous length of liner pipe with air at superatmospheric pressure to cause it to expand into engagement with the internal wall of the underground pipe or underground   
     
     
        main to be lined..Iaddend..Iadd.13.  A method of lining an underground pipe or underground main, said method comprising the steps of: (a) preheating a continuous length of synthetic-resin liner pipe of external diameter substantially equal to or greater than the internal diameter of the underground pipe or underground main to be lined;   (b) drawing the so-heated continuous length of liner pipe into the underground pipe or underground main to be lined through at least one swaging die dimensioned to reduce the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined;   (c) reducing the external diameter of the continuous length of liner pipe on the order of about 3% to about 10% less than the internal diameter of the underground pipe or underground main to be lined; and   (d) pressurizing the internal wall of the continuous length of liner pipe with air at superatmospheric pressure to cause it to expand into engagement with the internal wall of the underground main to be lined..Iaddend..Iadd.14. A method of lining an underground pipe or underground main, said method comprising the steps of:   (a) preheating a continuous length of synethetic-resin liner pipe of external diameter substantially equal to or greater than the internal diameter of the underground pipe or underground main to be lined;   (b) drawing the so-heated continuous length of liner pipe into the underground pipe or underground main to be lined through at least one swaging die dimensioned to reduce the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined;   (c) reducing the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined; and   (d) pressurizing the internal wall of the continuous length of liner pipe with air at superatmospheric pressure of about 2 bar to about 6 bar to cause it to expand into engagement with the internal wall of the   
     
     
        underground pipe or underground main to be lined..Iaddend..Iadd.15.  A method as claimed in claim 12 wherein; the step of reducing the external diameter of the continuous length of liner pipe comprises reducing said diameter on the order of about 3% to about 10%..Iaddend..Iadd.16. A method as claimed in claim 12 wherein;   the step of pressurizing the internal wall of the continuous length of liner pipe is carried out at a pressure of about 2 bar to about 6 bar..Iaddend..Iadd.17. A method as claimed in claim 13 wherein;   the step of pressurizing the internal wall of the continuous length of liner pipe is carried out at a pressure of about 2 bar to about 6   
     
     
        bar..Iaddend..Iadd.18.  A method as claimed in claim 12 wherein; (a) the step of reducing the external diameter of the continuous length of liner pipe comprises reducing said external diameter on the order of about 3% to about 10%; and   (b) the step of pressurizing the internal wall of the continuous length of liner pipe is carried out at a pressure of about 2 bar to about 6   
     
     
        bar..Iaddend..Iadd.19.  A method of lining an underground pipe or underground main, said method comprising the steps of: (a) preheating a continuous length of synthetic-resin liner pipe of external diameter substantially equal to or greater than the internal diameter of the underground pipe or underground main to be lined;   (b) drawing the so-heated continuous length of liner pipe into the underground pipe or underground main to be lined through at least one swaging die, which is above ground and out of axial alignment with the underground pipe or underground main to be lined, said die being dimensioned to reduce the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined;   (c) reducing the external diameter of the continuous length of liner pipe to less than the internal diameter of the underground pipe or underground main to be lined; and   (d) pressurizing the internal wall of the continuous length of liner pipe with air at superatmospheric pressure to cause it to expand into engagement with the internal wall of the underground pipe or underground   
     
     
        main to be lined..Iaddend..Iadd.20.  A method as claimed in claim 19 in which the continuous length of liner pipe is preheated by means of a portable heating device..Iaddend..Iadd.21. A method as claimed in claim 20 in which the portable heating device comprises a heating chamber through which, in use, the continuous length of liner pipe is drawn..Iaddend..Iadd.22. A method as claimed in claim 21 in which the heating chamber includes the at least one swaging die..Iaddend..Iadd.23. A method as claimed in claim 19 in which the continuous length of liner pipe is drawn into the underground pipe or underground main to be lined by means of a cable attached to the leading edge of the continuous length of liner pipe..Iaddend..Iadd.24. A method as claimed in claim 23 in which the cable is wound onto the drum of a motorized winch to draw the continuous length of liner pipe into the underground pipe or underground main to be lined..Iaddend..Iadd.25. A method as claimed in claim 19 in which a succession of lengths of synthetic-resin pipe are butt-welded together to obtain the continuous length of liner pipe which is then preheated..Iaddend..Iadd.26. A method as claimed in claim 19 in which both ends of the continuous length of liner pipe are closed with closures to enable the internal wall of the continuous length of liner pipe to be 
     
     
        pressurized..Iaddend..Iadd.27.  A method as claimed in claim 19 in which the synthetic-resin is polyethylene..Iaddend.