Pipes and tubular conduits – Repairing – Patches
Patent
1990-12-18
1992-04-07
Bryant, III, James E.
Pipes and tubular conduits
Repairing
Patches
138 97, 138154, 264269, 405150, 4051501, F16L 5518, B29C 6334
Patent
active
051018632
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of rehabilitating underground pipes with a lining comprising a helically wound liner pipe made of a synthetic resin, this comprises the steps of winding a strip of a synthetic resin into a helical shape around a virtual cylinder, so that the side edges of the wound strip are interengaged with each other, and continuously introducing the helically wound liner pipe hereafter referred to as a "liner pipe", into an underground pipe while the liner pipe is being advanced inside the underground pipe, and then fixing the leading end of the liner pipe to the underground pipe and further advancing the liner pipe being formed inside the underground pipe so that the wound strip is allowed to slide around the virtual cylinder with is side edges still interengaged with each other to result in a gradual progressive increase in the diameter of the liner piper toward the winding machine end.
2. Description of the Related Art
The method of forming such helical pipes has already been disclosed in Patent literature, see for instance European Patent Office Publication No. 0001894 in the name of Ri Loc Hong Kong Limited, or Patent Co-operation Treaty Publication No. WO85/03755 in the name of Rib Loc Hong Kong Limited which related to a modification of the system, and see particularly Patent Co-operation Treaty Publication No. WO89/01588 in the name of Rib Loc Australia Pty. Ltd. which related to restraining means for such a pipe structure to control the progressive expansion of the helically wound liner pipe in the underground pipe.
SUMMARY OF THE INVENTION
Thus according to the described method of rehabilitating underground pipes with a lining formed of a helically wound liner piper made of a synthetic resin, the liner pipe has a comparatively small diameter when being introduced into the underground pipe because the interconnected side edges of the convolutions of the wound strip are securely engaged with each other by use of a wire rod, so that it can smoothly advance inside the underground pipe without being disturbed by frictional resistance, which would be exerted by the inner surface of the underground pipe on the helical liner pipe.
After the liner piper is introduced into the underground pipe and the leading end of the helical liner pipe is fixed to the underground pipe, the restraining member is removed from the strip, bringing about the slackening of the engagement between the interengaged side edges of the wound strip, so that the wound strip slides around a virtual cylinder, resulting in a increase in diameter of the liner pipe.
Consequently, the outer diameter of the liner piper is made substantially equal to the inner diameter of the underground pipe; and the cross-sectional area of the underground pipe with the lining formed by the liner pipe is substantially equal to that of the underground pipe without the lining, so that the amount of a fluid which flows through the pipe with the lining per unit minute is substantially equal to or even greater than that which flows through the pipe without the lining per unit minute, depending on the type of the underground pipe to be rehabilitated.
Because the sliding of the wound strip around a virtual cylinder is physically prevented by the restraining member, the formation of the liner pipe can be performed without difficulty even when the liner pipe gets wet inside sewage pipes or during rainy weather.
The present invention relates generally to the described system but is specifically directed to further improvements, particularly a method which allows the space between the expanding pipe to be filled by injecting a backfilling material into the space between the outer surface of the liner piper and the inner surface of the underground pipe, the method consisting of moving a unit for supplying the backfilling material in the direction of the axis of the liner pipe as the portion of the said liner pipe with the increasing diameter is moved in the same direction.
The backfilling m
REFERENCES:
patent: 4647072 (1987-03-01), Westman
patent: 4678370 (1987-07-01), Allen
patent: 4867203 (1989-09-01), de Putter
patent: 4897911 (1990-02-01), Keldany et al.
Fujii Shigeki
Hirayama Hirozo
Sonku Masahisa
Yasuhara Minoru
Bryant III James E.
Peterson Gordon L.
Rib Loc Australia Pty. Ltd.
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