Method and apparatus for magnetic detection of flaws
First Claim
1. A system for detecting structural inhomogeneities in a component to be tested, comprising in combination:
- (a) means for selectively establishing at least one multi-dimensional test current in said component to produce a magnetic field detectable adjacent to the surface of said component;
(b) means for selectively and sequentially changing at least one parameter of said multi-dimensional test current, said at least one parameter being selected from a list which includes,(1) the frequency of said multi-dimensional test current;
(2) the amplitude of said multi-dimensional test current;
(3) the orientation of said multi-dimensional test current with respect to said component;
(c) means for detecting the magnitude of said magnetic field at a plurality of locations adjacent to said surface of said component to form a selected number of data arrays having a predetermined relationship to the electrical conductivity characteristics of said component; and
(d) means for analyzing said data arrays to determine if said component includes structural inhomogeneities.
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Accused Products
Abstract
An array of SQUID detectors to map the magnetic field associated with test currents flowing in the component to be tested. The SQUID is an ultrasensitive, miniature device that transduces a faint magnetic field to a measurable voltage. Perturbation occurs in the test currents and the associated magnetic field at physical defects or inhomogeneities. Multi-dimensional test currents are injected into the component being tested; the injection being made between specific electrodes by varying the direction of the current until it is normal to the direction of the defect to maximize and amplify the effect of the perturbation. The perturbation is detected by the SQUID grid which pinpoints the location, orientation, and size of the defect. The frequency of the injected current can be made to sweep the spectrum from DC to the highest response limit of the SQUID to scan for defects at various depths. As the frequency increases, "skin effect" decreases the depth of the test current permitting multi-dimensional profiles of the defect to be imaged. Computer processing permits high resolution images of inhomogeneities to be produced.
66 Citations
47 Claims
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1. A system for detecting structural inhomogeneities in a component to be tested, comprising in combination:
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(a) means for selectively establishing at least one multi-dimensional test current in said component to produce a magnetic field detectable adjacent to the surface of said component; (b) means for selectively and sequentially changing at least one parameter of said multi-dimensional test current, said at least one parameter being selected from a list which includes, (1) the frequency of said multi-dimensional test current; (2) the amplitude of said multi-dimensional test current; (3) the orientation of said multi-dimensional test current with respect to said component; (c) means for detecting the magnitude of said magnetic field at a plurality of locations adjacent to said surface of said component to form a selected number of data arrays having a predetermined relationship to the electrical conductivity characteristics of said component; and (d) means for analyzing said data arrays to determine if said component includes structural inhomogeneities. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for detecting inhomogeneities in a component, comprising in combination:
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(a) means utilizing at least one multi-dimensional test current to establish a magnetic field having a selected magnitude and a selected orientation in said component; (b) means for selectively changing said selected orientation; (c) means for detecting the magnetic field in a plane having a predetermined relationship to a surface of said component to produce a data array; and (d) means for analyzing each of said data arrays to determine the location and characteristics of said inhomogeneity.
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16. A system for detecting inhomogeneities in a component comprising in combination;
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(a) means for injecting at least one multi-dimensional test current into said component, said multi-dimensional test current having parameters including frequency, amplitude and orientation with respect to said component which may be selectively and sequentially varied; (b) means for selectively and sequentially varying said parameters; (c) means for detecting the magnetic field associated with said multi-dimensional test current comprising two or more arrays of SQUID detectors with members of said arrays off-set such that the responsive area of selected members of said arrays partially overlap to produce at least first and second data bases; and (d) means for analyzing said data bases to produce a magnetic map having a resolution higher than similar maps produced using a reduced number of data bases.
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17. A system for producing a multi-dimensional image of inhomogeneities in a component, comprising in combination:
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(a) means for establishing a sequential plurality of multi-dimensional test currents in the component to be tested, each of said plurality of multi-dimensional test currents having parameters which may be selectively changed; (b) means for selectively varying said parameters; (c) means for producing a multi-dimensional map of the magnetic fields associated with said multi-dimensional test currents; and (d) means for analyzing said multi-dimensional maps to produce a multi-dimensional image of said inhomogeneities.
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18. A system for detecting inhomogeneities in a rotating component, comprising in combination:
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(a) means for establishing a predetermined pattern of multi-dimensional test currents in said rotating component, said multi-dimensional test currents having parameters including frequency, orientation and amplitude which can be selectively and sequentially varied; (b) means positioned at a fixed location relative to said rotating component to detect magnetic fields related to said multi-dimensional test currents to form a data array; (c) means for analyzing said data array to detect any inhomogeneities in said rotating component. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A method for detecting inhomogeneities in a component, comprising the steps of:
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(a) producing at least one multi-dimensional test current having selectively variable parameters in said component to establish a magnetic field having a selected magnitude and a selected orientation in said component; (b) detecting said magnetic field in a plane having a predetermined relationship to a surface of said component to produce a data array; and (c) analyzing each of said data array to determine the location, depth and characteristics of said inhomogeneities.
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27. A method for detecting structural inhomogeneities in a component to be tested, comprising the steps of:
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(a) selectively establishing at least one multi-dimensional test current having selectively variable parameters in said component to produce a magnetic field detectable adjacent to the surface of said component; (b) detecting the magnitude of said magnetic field at a plurality of locations adjacent to a surface of said component to form a selected number of data arrays having a predetermined relationship to the electrical conductivity characteristics of said component; and (c) analyzing said data arrays to determine if said component includes structural inhomogeneities. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35)
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36. A method for detecting inhomogeneities in a component, comprising in combination:
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(a) producing at least one multi-dimensional test current having selectively variable parameters in said component; (b) detecting the magnetic field produced by said multi-dimensional test current utilizing two or more arrays of SQUID detectors with members of said arrays off-set such that the action response of selected members of said arrays partially overlap to produce first and second data basis; and (c) analyzing said data bases to produce a magnetic map having a resolution higher than similar maps produced using a reduced number of data bases.
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37. A method for producing a multi-dimensional image of inhomogeneities in a component, comprising in combination:
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(a) producing at least one multi-dimensional test current having selectively and sequentially variable parameters in the component to be tested;
(b) detecting the magnetic fields associated with said at least one multi-dimensional test current to produce a multi-dimensional map of the magnetic fields; and(c) analyzing said multi-dimensional maps to produce a multi-dimensional image of said inhomogeneities.
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38. A method for detecting inhomogeneities in a rotating component, comprising the steps of:
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(a) establishing a predetermined pattern of at least one multi-dimensional test current having selectively and sequentially variable parameters in said rotating component; (b) detecting the magnetic fields produced by said one or more multi-dimensional test currents at a selected fixed location to produce a data array; and (c) analyzing said data array to detect any inhomogeneities in said rotating component. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46)
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47. A method of testing at least one component forming a part of rotating electrical machines, comprising the steps of:
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(a) establishing at least a plurality of multi-dimensional test current in said component, a first one of said multi-dimensional test currents having a first orientation with respect to the axis of rotation of said retaining ring, a second one of said multi-dimensional test currents having a second orientation with respect to the axis of rotation of said retaining ring, said first orientation differing from said second orientation; (b) utilizing a plurality of sensors positioned adjacent a surface of said component to produce at least first and second data bases, said first and second data base respectively having first and second predetermined relationships to the flow pattern of said first and second positions of said multi-dimensional test currents; (c) processing said first and second data bases to produce data having a predetermined relationship to the integrity of said retaining ring.
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Specification