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.

Date of Patent:
Dec. 17, 1985

Filed:

Apr. 04, 1984
Applicant:
Inventors:

Peter F Roach, Warrington, GB;

Edward Duncombe, Altrincham, GB;

Ian Hulse, Warrington, GB;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B23K / ;
U.S. Cl.
CPC ...
219 / ; 219 602 ; 219 / ; 228119 ;
Abstract

Prior to effecting a repair of a leaking heat exchanger tube by an internal repair tube brazed to the leaking tube, strain in the leaking tube is measured while heating it to brazing temperature. A braze is only effected if the strain is below a predetermined level. Apparatus for carrying out the strain measurement typically of probe form having a strain gauge head (21) at the nose of the probe and a heater element (23). Preferably, the length of the probe is such that the head (21) reaches to just above a grid support plate (12). Where strain is found to be above said predetermined level and the leaking tube is of U-shape the strain may be relieved by heating both legs of the tube. Alternatively, strain may be relieved by thinning and bulging the leaking tube (FIGS. 5A-C) at a region close enough to the braze for the thinned zone to experience heat from the braze to allow it to yield under the strain.


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