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US 5,078,430 AGranted
Pipeline for relining sewers and water lines without excavation
AssigneeDuratron Systems Limited
InventorHenri S. St. Onge
Life of this patent
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AssigneeDuratron Systems Limited
InventorHenri S. St. Onge
Estimating the term…
A method is disclosed for relining buried pipeline with interconnectable plastic type pipe sections. The method comprises gaining access to an open end of the buried pipeline, such as through a manhole, passing pipe sections down the manhole and inserting individually each pipe section into the buried pipeline open end. Each pipe section is of a length to permit, within the confines of the manhole, insertion of each pipe section into the pipeline open end. Each pipe is of a diameter to fit within the pipeline. The pipe section to be inserted is interconnected to the pipe section already inserted within the buried pipeline. Such interconnected sections are sequentially moved into the buried pipeline to permit insertion of the next pipe section into buried pipeline until the entire length of the pipeline to the next access area has been relined.
A length of plastic pipe made of a material selected from the group consisting of polyethylene, polypropylene and polyvinyl chloride, said length of plastic pipe being generally rigid and of generally constant exterior dimensions, said length of plastic pipe at one end and interior to said constant exterior dimensions including an interior female connection, said length of pipe at the end opposite said female connection having a corresponding male connection sized for insertion into a female connection of a like length of pipe and form therewith a releasable joint of an exterior diameter equal to the exterior dimensions of the length of plastic pipe which can withstand axial tensile forces experienced in drawing the pipe lengths into an existing pipeline to reline the same, said releasable joint including as the sole means for resisting tensile forces opposed radial surfaces defined by said male and female connections which about during the application to the joint of axial tensile forces, said joint being formable by the force fit of a male connection axially into a female connection due to the deformability of the plastic pipe and a cooperation of contact surfaces of said male and female connections which assist in said surfaces riding over the other during insertion.
In a piping system comprised of a number of interconnected plastic pipe sections, mechanical connections between adjacent pipe sections which are integral with the pipe sections, each mechanical connection comprising a male portion inserted in and retained by a female portion which cooperate and are sized relative to the pipe sections to provide a generally constant interior and exterior diameter to said pipe sections, said male and female portions including as the sole means opposed flat radially extending surfaces which abut and oppose any forces tending to cause axial withdrawal of said male and female portions, said male and female portions having other angled surfaces allowing said male and female portions to be simply connected while said flat radially extending surfaces provide a strong interlock opposing axial withdrawal of connected pipe sections.
Dependencies are inferred from the claim text.