METHOD OF LINING METAL PIPELINES Russian patent published in 2016 - IPC F16L9/147 F16L58/10 F16L55/165 

FIELD: technological processes.

SUBSTANCE: invention relates to a method of lining metal pipeline. Method comprises the following stages: (i) processing thermoplastic fluoropolymer composition to produce a casing pipe having the outer diameter larger than the inner diameter of the said metal pipeline, herewith the said thermoplastic fluoropolymer composition includes: (A) from 10% to 60 wt% per the total weight of polymer (A) and polymer (B) of at least one vinylidene fluoride (VDF) homopolymer [polymer (A)], (B) from 40% to 90 wt% per the total weight of polymer (A) and polymer (B) of at least one VDF copolymer, containing from 2% to 15 mol% of repeating units derived from at least one another fluorinated comonomer (F) [polymer (B)], and (C) of at least one plasticiser; (ii) deformation of the said inner pipe for producing a deformed pipe with the outer diameter smaller than the inner diameter of the said metal pipeline; (iii) enter of the deformed inner pipe into the said metal pipeline; and (iv) increase of the deformed casing pipe for its fitting to the inner diameter of the said metal pipeline. Invention also relates to a system of pipelines, including at least two coaxial pipes, the external metal pipe and the casing pipe made from the said composition of thermoplastic fluoropolymer.

EFFECT: higher strength.

11 cl, 2 tbl