(19)
(11) EP 0 128 644 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.07.1985 Bulletin 1985/28

(43) Date of publication A2:
19.12.1984 Bulletin 1984/51

(21) Application number: 84302486

(22) Date of filing: 11.04.1984
(84) Designated Contracting States:
BE DE FR GB IT NL SE

(30) Priority: 13.04.1983 GB 8309988
13.05.1983 GB 8313266

(71) Applicant: UNITED KINGDOM ATOMIC ENERGY AUTHORITY
 ()

(72) Inventors:
  • Roach, Peter Francis
     ()
  • Duncombe, Edward
     ()
  • Hulse, Ian
     ()
  • Stacey, John
     ()

   


(54) Heat exchanger tube repair


(57) @ 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 whilst 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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