(19)
(11) EP 0 151 404 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.10.1985 Bulletin 1985/42

(43) Date of publication A2:
14.08.1985 Bulletin 1985/33

(21) Application number: 85100365

(22) Date of filing: 16.01.1985
(84) Designated Contracting States:
BE CH DE FR GB IT LI SE

(30) Priority: 03.02.1984 US 576678

(71) Applicant: WESTINGHOUSE ELECTRIC CORPORATION
 ()

(72) Inventors:
  • Calhoun, Gregory Lee
     ()
  • Candee, Clark Bennett
     ()

   


(54) Eddy current positioning apparatus for sludge lance


(57) A sludge lance nozzle for removing sludge from between the tubes of a nuclear steam generator includes positioning apparatus mounted on top of the nozzle. The positioning apparatus includes a cylindrical eddy-current sensor mounted inside a cup-shaped non-magnetic electrically insulating spacer, which is in turn mounted in a cup-shaped support member fixedly secured to the nozzle. The tubes are arranged in rows and columns with the axes of the tubes in each column lying in a common column plane. The nozzle is moved perpendicular to the column planes close to one of the rows of tubes. The sensor produces a maximum-amplitude output signal when the sensing axis is coplanar with the column plane of a tube in the closest row of tubes and a minimum-amplitude output signal when the sensing axis is midway between adjacent tubes in the closest row of tubes.






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