METHOD OF REPAIRING SECTION OF GAS PIPELINE WITH FACTORY INSULATION COATING Russian patent published in 2024 - IPC F16L1/24 

FIELD: oil, gas and coke-chemical industry.

SUBSTANCE: invention relates to operation of linear part of main gas pipelines. In particular, invention relates to operation of sections with factory insulation coating with service life of more than 30 years, in which the surface under the factory coating complies with the standard requirements, and the welded seams and the adjacent heat-affected zone are defective. According to the results of in-pipe technical diagnostics, welds with defects of the welded seam and heat-affected zone on the sections laid by elastic bend are determined. At gas-free section of main gas line containing more than one defective seam, opening is performed up to middle generatrix. In the area of defective welds, bore is performed with a trench with a depth of at least 0.6 m from the lower generatrix and width of 2 m. Seams and heat-affected zone are cleaned from old insulating coating of route application. Pipe cutting device is used to cut out defective seams and adjacent defective heat-affected zone of 0.1 m without factory coating, with simultaneous design of the edge for a new butt weld. Pipelayers are used to pull the cut out pipe to the place prepared for butt welding. Weld and heat-affected zone are cleaned, butt weld is tacked and welded, followed by welding quality control. Seam and heat-shrinking zone are cleaned in compliance with the requirements for preparation of the pipe surface for the heat-shrinking collar; the heat-shrinking collar is installed. On the final defective seam, a coil is inserted with the size of not less than the diameter of the pipeline.

EFFECT: reduction of labour intensity and material costs during repair in route conditions.

1 cl, 5 dwg