Method of lining of metallic pipe using a plurality of concentric flexible tubes of thermoplastic polymer
AssigneeDu Pont Canada Inc.
InventorGeorge White
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Abstract
A method of lining of metallic pipe is disclosed. The method comprises forming a plurality of concentric flexible tubes of a thermoplastic polymer, such tubes being capable of being bonded together under the influence of heat and pressure. The plurality of concentric tubes is inserted into a section of metallic pipe that is to be lined. The tubes are then heated, especially under pressure e.g. using steam, to cause the tubes to bond together to form a single tube lining the pipe. Adhesives may be used to facilitate bonding. The method is particularly useful in the lining of metallic pipe that has bends, loops or the like.
Claims6
A method of lining of metallic pipe consisting essentially of:
- (a) forming a plurality of at least five concentric flexible tubes from film of thermoplastic polymer, said thermoplastic polymer being selected from the group consisting of polyethylene and polyamide, said tubes having a coating of grafted polyolefin on at least one surface thereof such that in the plurality of concentric tubes at least one tube surface in face-to-face relationship with another tube surface has said coating thereon;
- (b) simultaneously inserting each flexible tube into a section of metallic pipe by pulling said plurality of tubes into the pipe;
- (c) inflating the tubes using a fluid under pressure;
- and
- (d) heating the tubes within the pipe to cause the tubes to be bonded together to form a single tube lining said metallic pipe;
- each tube of the plurality of tubes having a thickness in the range of about from 40 to 800 microns, and the thickness and number of tubes being selected to provide said single tube with a total thickness of about from 0.1 to 2.5 cm.
Dependencies are inferred from the claim text.