METHOD FOR REPAIRING METALLIC PIPELINES Russian patent published in 2000 - IPC

FIELD: building industry branch, namely repairing pipelines at restoration of reservoirs, boilers, high pressure vessels. SUBSTANCE: method for repairing pipelines with defect zones is realized by means of application of couplings. Method comprises steps of mechanically cleaning surface of pipeline ( at reduced pressure) from insulation coating and rust, degreasing it, spraying onto it rust converter, applying tensioned band for further fixation of coupling on pipeline at heating tube surface and levelling it by means of high-strength paste. At repairing annular seam or adjacent defect zones three couplings are applied. Said couplings are spaced from each side of welding seam or adjacent defect zones by distance no more than 5 mm. Space between lateral couplings are filled with self-hardening matter. After hardening of said matter central upper coupling is applied; edges of central coupling are equidistant relative to seam center or to axis of ring of adjacent defect zones. If it is necessary to repair large-length portion of pipeline couplings are applied step by step successively one after another with mutual spacing no less than 200 mm and no more than one diameter of repaired tube. In description of invention there are given mathematical relations for determining size of couplings in dependance upon length of defect and for determining degree of pressure reduction in pipeline. EFFECT: enhanced operational reliability of pipeline. 9 cl, 4 dwg