Improvement on Remediation Technology for Type B Full-encirclement Steel Sleeves

Because of serious aging problem existed in Eastern Oil Pipelines Networks, a lot of defects in circular welds and spiral welds need to be repaired by sleeve way Traditional type B sleeve is not suitable to eliminate this kind of defects due to the wetd reinforcement and low tightness between the sleeve and pipe wall, and meanwhile, concentrated interaction force will effect on welds' top, which result in a poor repair quality and crack growing, Based on software simulation and mechanical analysis, a new type B convex sleeve is developed whose wall reserves weld groove which can transfer the welds when it is installed, therefore, the problems in low tightness between the traditional type B sleeve and pipe body with defects, the high difficulty in welding and poor repair quality for the traditional type B sleeve are solved, The bursting-proof capacity of pipe repaired by this new type B convex sleeve can reach to 14 MPa, which is much higher than the practical operating pressure and yield pressure of the pipe.