Apparatus for loosening a mechanical plug in a heat exchanger tube

Abstract

An apparatus and method for loosening a mechanical plug in a tube. A cartridge having a nose portion, central portion formed from a material that produces an exothermic reaction when ignited, and a base is inserted into the plug to be loosened and removed. An insulated wire extends through the base into the central portion and is connected to a resistive noninsulated wire positioned in the central portion. Sending an electrical current through the wiring causes the noninsulated wire to heat up rapidly. The rapid heat buildup initiates an exothermic reaction in the central portion. The heat generated causes stress conditions in the plug that exceed plug yield and results in a stress relief condition in the plug where the diameter of the plug is reduced. This loosens the plug in the tube and reduces pulling forces needed to remove the plug from the tube.

Dependencies are inferred from the claim text.