METHOD FOR REPAIRING METAL PIPE

摘要

A method for repairing metal pipe with dents includes steps of a) holding the pipe with first and second ends in position; b) dragging the mandrel through the pipe; and c) pushing out the dents from inside to an original level of the surface of the pipe. The cross-section of the mandrel has a substantially same cross-section of the hollow space of a undamaged pipe, and the outer surface of the major portion of the mandrel fits tightly to the inside of the undamaged pipe. The step of holding the pipe includes steps of a) guiding the pipe into a locking position; b) stopping the pipe along the direction of the axis of the pipe; and c) stopping the pipe along the perpendicular direction of the axis of the pipe.