Temperature, stress, and corrosive sensing apparatus utilizing harmonic response of magnetically soft sensor element (s)
First Claim
1. A temperature sensing apparatus, comprising:
- a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, said first time-varying magnetic field being generated at a frequency higher than that for said second magnetic field;
a receiver, remote from said sensor element, to measure intensity of electromagnetic emissions from said sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured; and
a unit to determine a value for temperature using said relative maximum harmonic amplitude values identified.
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Abstract
A temperature sensing apparatus including a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, the first time-varying magnetic field being generated at a frequency higher than that for the second magnetic field. A receiver, remote from the sensor element, is engaged to measure intensity of electromagnetic emissions from the sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured. A unit then determines a value for temperature (or other parameter of interst) using the relative maximum harmonic amplitude values identified. In other aspects of the invention, the focus is on an apparatus and technique for determining a value for of stress condition of a solid analyte and for determining a value for corrosion, using the relative maximum harmonic amplitude values identified. A magnetically hard element supporting a biasing field adjacent the magnetically soft sensor element can be included.
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Citations
28 Claims
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1. A temperature sensing apparatus, comprising:
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a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, said first time-varying magnetic field being generated at a frequency higher than that for said second magnetic field;
a receiver, remote from said sensor element, to measure intensity of electromagnetic emissions from said sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured; and
a unit to determine a value for temperature using said relative maximum harmonic amplitude values identified. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
the said sensor element is elongated, having a length, e, from 1 mm to 1000 mm, and is made of a ferromagnetic alloy;
said solid analyte comprises a laminate of at least two components from said group; and
said sensor element is at least partially encapsulated within a corrosion-resistant casing and is interposed between said two components.
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8. The apparatus of claim 6 wherein the said sensor element is elongated, having a length, e, from 1 mm to 1000 mm, and is embedded within said solid analyte, and said temperature value, T, is determined according to the expression:
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9. The apparatus of claim 1 wherein the sensor element is located on a surface of a solid analyte, said value for temperature represents a localized surface temperature of said solid analyte, and said solid analyte comprises a component of a material selected from the group consisting of concrete, mortar, tar, wood, fiberboard, particleboard, plasterboard, sheetrock, fiberglass, plexiglass, resins, and plastics.
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10. The apparatus of claim 1 further comprising a magnetically hard element supporting a biasing field adjacent said magnetically soft sensor element, said magnetically hard element comprised of a material chemically responsive to a fluid analyte such that exposure thereto causes a change in said biasing field.
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11. The apparatus of claim 1 wherein said first time-varying interrogation magnetic field comprises a signal-burst generated at said higher frequency, said measure of emissions is performed while sweeping said second time-varying field and while said signal-burst is transmitted by an interrogation field generating coil, said interrogation field generating coil is adapted for generating said second field, and said plurality of higher-order harmonic amplitudes so measured are for harmonics selected from a range of 2 to 100 times a fundamental resonant frequency for said sensor element.
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12. An apparatus for sensing stress conditions of a solid analyte, comprising:
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a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, said first time-varying magnetic field being generated at a frequency higher than that for said second magnetic field;
a receiver, remote from said sensor element, to measure intensity of electromagnetic emissions from said sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured; and
a unit to determine a value for stress conditions of the analyte in proximity to said sensor element using said relative maximum harmonic amplitude values identified. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 28)
said sensor element is embedded within said solid analyte, said solid analyte comprises a component of a material selected from the group consisting of concrete, mortar, tar, wood, fiberboard, particleboard, plasterboard, sheetrock, fiberglass, plexiglass, resins, and plastics;
said plurality of higher-order harmonic amplitudes so measured are for harmonics selected from a range of 2 to 100 times a fundamental resonant frequency for said sensor element; and
said sensor element is at least partially encapsulated within a corrosion-resistant casing.
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17. The apparatus of claim 12 wherein the sensor element is located on a surface of a solid analyte, said value for stress conditions represents a localized surface stress of said solid analyte, and said solid analyte comprises a component of a material selected from the group consisting of concrete, mortar, tar, wood, fiberboard, particleboard, plasterboard, sheetrock, fiberglass, plexiglass, resins, and plastics.
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18. The apparatus of claim 12 further comprising a magnetically hard element supporting a biasing field adjacent said magnetically soft sensor element, said magnetically hard element comprised of a material chemically responsive to a fluid analyte such that exposure thereto causes a change in said biasing field.
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19. The apparatus of claim 12 wherein said first time-varying interrogation magnetic field comprises a signal-burst generated at said higher frequency, said measure of emissions is performed while sweeping said second time-varying field and while said signal-burst is transmitted by an interrogation field generating coil, said interrogation field generating coil is adapted for generating said second field, and said plurality of higher-order harmonic amplitudes so measured are for harmonics selected from a range of 2 to 100 times a fundamental resonant frequency for said sensor element.
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28. The apparatus of claim 19 wherein said first time-varying interrogation magnetic field comprises a signal-burst generated at said higher frequency, said measure of emissions is performed while sweeping said second time-varying field and while said signal-burst is transmitted by an interrogation field generating coil, and said plurality of higher-order harmonic amplitudes so measured are for harmonics selected from a range of 2 to 100 times a fundamental resonant frequency for said sensor element.
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20. An apparatus for monitoring a corrosive, comprising:
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a sensor element made of a magnetically soft material operatively arranged within a first and second time-varying interrogation magnetic field, said first time-varying magnetic field being generated at a frequency higher than that for said second magnetic field;
a receiver, remote from said sensor element, to measure intensity of electromagnetic emissions from said sensor element to identify a relative maximum amplitude value for each of a plurality of higher-order harmonic frequency amplitudes so measured; and
a unit to determine a value for corrosion in proximity to said sensor element using said relative maximum harmonic amplitude values identified. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification