Electricity: measuring and testing – Magnetic – With means to create magnetic field to test material
Reexamination Certificate
2006-02-24
2011-11-22
Patidar, Jay (Department: 2858)
Electricity: measuring and testing
Magnetic
With means to create magnetic field to test material
C324S238000, C324S240000
Reexamination Certificate
active
08063631
ABSTRACT:
A device for non destructive evaluation of defects in a metallic object (2) by eddy currents, comprises a field emitter (3) for emitting an alternating electromagnetic field at a first frequency fi in the neighborhood of the metallic object (2), and a magnetoresistive sensor (1) for detecting a response signal constituted by a return electromagnetic field which is re-emitted by eddy currents induced by the alternating electromagnetic field in the metallic object (2). The device further comprises: a driving circuit (230) for driving the magnetoresistive sensor (1) by a current at a second frequency fc which is different from the first frequency fi, so that the magnetoresistive sensor (1) acts as an in situ modulator; a detector for detecting a response signal between the terminals of the magnetoresistive sensor (1); a filter for filtering the response signal detected by the magnetoresistive sensor (1) to keep either the frequency sum (fi+fc) of the first and second frequencies or the frequency difference (fi−fc) of the first and second frequencies, and a processor for processing the filtered response signal and extract eddy current information on defects in the metallic object (2).
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Biziere Nicolas
Fermon Claude
Pannetier Myriam
Sollier Thierry
Vacher Francois
Commissariat a l'Energie Atomique et aux Energies Alternatives
Patidar Jay
Weingarten Schurgin, Gagnebin & Lebovici LLP
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