Superconductive quantum interference device for the non-destructive evaluation of metals
First Claim
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1. A method of nondestructive evaluation of locations of flaws in a metal body, comprising the steps of:
- (a) positioning a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop in a flux-sensing relationship to a location adjoining said body;
(b) relatively displacing said body and said location;
(c) while said body and said location are relatively displaced, exciting said body with a modulated alternating current and detecting with said device flux irregularities representing flaws in said body;
(d) establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, a plurality of said devices being connected in series are juxtaposed with said body;
(e) demodulating a signal generated by the series-connected devices to form an output; and
(f) connecting respective modulating coils inductively coupled to the respective high-critical-temperature superconductive quantum interference devices and connected to said output in a feedback path to form a flux-locked loop with said high-critical-temperature superconductive quantum interference devices.
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Abstract
High-Tc superconductor quantum interference devices (SQUIDs) for noise-free, accurate measurements of defects and flaws in metal shapes and forms by measuring changes in the secondary magnetic field intensity around any point which is excited by a primary excitation current or by measuring changes in the impedance of the exciting coils. These measured changes are correlated to defects and flaws present in the metal.
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Citations
15 Claims
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1. A method of nondestructive evaluation of locations of flaws in a metal body, comprising the steps of:
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(a) positioning a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop in a flux-sensing relationship to a location adjoining said body; (b) relatively displacing said body and said location; (c) while said body and said location are relatively displaced, exciting said body with a modulated alternating current and detecting with said device flux irregularities representing flaws in said body; (d) establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, a plurality of said devices being connected in series are juxtaposed with said body; (e) demodulating a signal generated by the series-connected devices to form an output; and (f) connecting respective modulating coils inductively coupled to the respective high-critical-temperature superconductive quantum interference devices and connected to said output in a feedback path to form a flux-locked loop with said high-critical-temperature superconductive quantum interference devices. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of nondestructive evaluation of locations of flaws in a metal body, comprising the steps of:
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(a) positioning a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop in a flux-sensing relationship to a location adjoining said body; (b) relatively displacing said body and said location; (c) while said body and said location are relatively displaced, exciting said body with a modulated alternating current and detecting with said device flux irregularities representing flaws in said body; and (d) establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, said location being defined by a coil juxtaposed with said body and connected in series with a coil located remote from said body, said high-critical-temperature superconductive quantum interference device being juxtaposed with said coil located remote from said body.
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8. A method of nondestructive evaluation of locations of flaws in a metal body, comprising the steps of:
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(a) positioning a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop in a flux-sensing relationship to a location adjoining said body; (b) relatively displacing said body and said location; (c) while said body and said location are relatively displaced, exciting said body with a modulated alternating current and detecting with said device flux irregularities representing flaws in said body; (d) establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, said location being defined by a coil juxtaposed with said body and connected in series with a coil located remote from said body; and (e) inductively coupling said coil located remote from said body with said high-critical-temperature superconductive quantum interference device.
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9. An apparatus for nondestructive location of flaws in a metal body, comprising:
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a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop disposed in flux-sensing relationship to a location adjoining said body; means for relatively displacing said body and said location; means for exciting said body with a modulated alternating current while said body and said location are relatively displaced, whereby said device detects flux irregularities representing flaws in said body; means for establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, a plurality of said devices connected in series being juxtaposed with said body, means for demodulating a signal generated by the series-connected devices to form an output; and respective modulating coils inductively coupled to the respective high-critical-temperature superconductive quantum interference devices and connected to said output in a feedback path to form a flux-locked loop with said high-critical-temperature superconductive quantum interference devices. - View Dependent Claims (10, 11, 12, 13)
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14. An apparatus for nondestructive location of flaws in a metal body, comprising:
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a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop disposed in flux-sensing relationship to a location adjoining said body; means for relatively displacing said body and said location; means for exciting said body with a modulated alternating current while said body and said location are relatively displaced, whereby said device detects flux irregularities representing flaws in said body; and means for establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, said location being defined by a coil juxtaposed with said body and connected in series with a coil located remote from said body, said high-critical-temperature superconductive quantum interference device being juxtaposed with said coil located remote from said body.
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15. An apparatus for nondestructive location of flaws in a metal body, comprising:
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a high-critical-temperature superconductive quantum interference device having a pair of insulated junctions in a superconductor loop disposed in flux-sensing relationship to a location adjoining said body; means for relatively displacing said body and said location; means for exciting said body with a modulated alternating current while said body and said location are relatively displaced, whereby said device detects flux irregularities representing flaws in said body; means for establishing locations of said flaws by the relative positions of said location and said body upon the detection of said flux irregularities, said location being defined by a coil juxtaposed with said body and connected in series with a coil located remote from said body; and means for inductively coupling said coil located remote from said body with said high-critical-temperature superconductive quantum interference device.
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Specification