METHOD FOR LINING OF METAL TUBE WITH PLASTIC ENCLOSURE Russian patent published in 1999 - IPC

FIELD: plastic working of materials. SUBSTANCE: method involves widening ends of metal tube; introducing plastic enclosure into metal tube and mounting pinching rings; fastening ends of plastic enclosure and gaging widened part of tube ends along their outer diameter. Inner diameter of metal tube ends is widened to: d(p) ≥ D(1+ES)-S(1-li)+2t, where d(p) is widened inner diameter of metal tube end; D is nominal outer diameter of metal tube; S is nominal thickness of metal tube wall; ES is maximum allowable deviation of outer diameter of metal tube; ei is minimum allowable deviation of metal tube wall thickness; t is thickness of pinching ring wall. Outer diameter of widened ends of metal tube is gaged and ends of plastic enclosure are fastened between widened ends of metal tube and pinching rings by joint radial squeezing of ends of lined tube with pinching rings to diameter D(gaged) < D(1+EJ)+2t, where D(gaged) is gaged outer diameter of metal tube end; EJ is minimum allowable deviation of outer diameter of metal tube. Method allows tubes with uniform section to be obtained independently of metal tube outer diameter and wall thickness allowances. EFFECT: increased efficiency and improved quality of lined tubes by reliable corrosion protection of tubes and tube connections. 3 cl, 4 dwg, 1 tbl