The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 02, 1992
Filed:
May. 20, 1991
John C Griffith, Lynchburg, VA (US);
James E Gutzwiller, Forest, VA (US);
The Babcock & Wilcox Company, New Orleans, LA (US);
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.