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:
Apr. 17, 1990
Filed:
Feb. 21, 1989
Denis Yeo, Columbia, SC (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
An apparatus and method produces multi-level heat input for nuclear fuel rod weld formation using a single current level power supply. Different levels of electrical power are produced to achieve a low heat, high heat sequence by imposition of a sequence of inert atmospheric cover gases of different ionization energies at the welding site to regulate voltage drop and thereby electrical power level and heat input level for arc welding of the nuclear fuel rod to take place. A first cover gas, such as argon, is supplied to the weld chamber in a first welding pass for producing a high electrical current level and low heat input level, whereas a second cover gas, such as helium or a mixture of helium and argon, is supplied to the weld chamber in a second welding pass for producing low electrical current level and high heat input level. The first cover gas has a lower ionization energy than the second cover gas which results in a lower voltage drop and lower heat input during the first pass compared to the second pass so that the desired sequence of low heat first pass and high heat second pass is achieved.