Patent ID: 7475583

Claim:
A method for repairing metal pipe with dents comprising steps of: a) holding the pipe with first and second ends in position; b) dragging a mandrel through the pipe; and c) pushing out the dents from inside to an original level of the surface of the pipe, wherein a cross-section of the mandrel has a substantially same cross-section of a hollow space of a undamaged pipe, wherein an outer surface of the major portion of the mandrel fits tightly to the inside of the undamaged pipe, wherein the step of holding the pipe comprises steps of: guiding the pipe into a locking position along the direction of the an axis of the pipe; stopping the pipe along the direction of the axis of the pipe against pressure imparted by momentum transfer from the friction between the pipe and the mandrel; and stopping the pipe along the perpendicular direction of the axis of the pipe against pressure imparted by momentum transfer from the friction between the pipe and the mandrel, wherein the step of stopping the pipe along the perpendicular direction of the axis of the pipe comprises a step of using a plurality of V-shaped pipe rests and a plurality of hydraulic rams.