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US 5,004,724 AGranted
Superconductive quantum interference device for the non-destructive evaluation of metals
AssigneeInternational Superconductor Corp.
InventorDilip K. De
Life of this patent
Estimating the term…
Abstract
High-T.sub.c 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.
Claims15
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.
4 more elements
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;
- 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.
2 more elements
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, 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.
3 more elements
An apparatus for nondestructive location of flaws in a metal body, comprising:
- 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.
4 more elements
An apparatus for nondestructive location of flaws in a metal body, comprising:
- 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.
2 more elements
An apparatus for nondestructive location of flaws in a metal body, comprising:
- 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.
3 more elements
Dependencies are inferred from the claim text.