METHOD OF TIGHT CONNECTION OF THIN-WALLED HELICAL CORRUGATED PIPE LINES Russian patent published in 1999 - IPC

FIELD: welded permanent joints of pipe lines. SUBSTANCE: ends of sections of pipe line are cut by tops of corrugations over length of one turn, rolled out diameter equal to half sum of outer and inner diameters of corrugated pipe line and is placed between centering bush mounted inside and rings fitted on the outside and made in form of coil cylindrical spring. Rolled-out ends of sections which project from under rings by amount equal to 4-6 thicknesses of corrugated pipe lines are welded around by continuous seam. EFFECT: enhanced reliability of welded seam. 1 dwg