Method of and apparatus for in-situ measurement of changes in fluid composition by electron spin resonance (ESR) spectrometry
First Claim
1. A method of using electron spin resonance spectrometry for in situ measuring of a degradation of operating machinery fluids, the method comprising acts of:
- passing a sample of a fluid through a resonating RF microwave cavity resonator during the application therethrough of a swept uniform magnetic field;
wherein the fluid sample has a magnetic susceptibility and application of the swept uniform magnetic field causes a magnetic resonance that effects changes in the magnetic susceptibility of the sample at a RF frequency depending on a Zeeman field at the sample,modulating a modulation magnetic field, correspondingly to vary the magnetic susceptibility and the magnetic resonance in the fluid sample, which results in at least one of an RF phase modulation and an amplitude modulation; and
measuring at least one of the resulting RF phase modulation or amplitude modulation thereof to derive an electron spin resonance signal, whereby the electron spin resonance signal is indicative of molecular changes in the fluid sample resulting from fluid degradation during operation of the machinery.
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Accused Products
Abstract
A miniaturized instrument and method of using electron spin resonance spectrometry for measuring the degradation of lubricating fluids, and the like, that includes continuously passing a sample of such fluid through a resonating RF microwave cavity resonator during the application therethrough of a uniform slowly varying uniform magnetic field that is rapidly modulated and measuring the resulting phase modulation or amplitude modulation thereof to derive an electron spin resonance signal that directly senses the molecular changes in the fluid sample resulting from fluid degradation during operation of the vehicle, such as peroxy radicals in vehicle engine oil and the like.
28 Citations
13 Claims
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1. A method of using electron spin resonance spectrometry for in situ measuring of a degradation of operating machinery fluids, the method comprising acts of:
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passing a sample of a fluid through a resonating RF microwave cavity resonator during the application therethrough of a swept uniform magnetic field;
wherein the fluid sample has a magnetic susceptibility and application of the swept uniform magnetic field causes a magnetic resonance that effects changes in the magnetic susceptibility of the sample at a RF frequency depending on a Zeeman field at the sample,modulating a modulation magnetic field, correspondingly to vary the magnetic susceptibility and the magnetic resonance in the fluid sample, which results in at least one of an RF phase modulation and an amplitude modulation; and measuring at least one of the resulting RF phase modulation or amplitude modulation thereof to derive an electron spin resonance signal, whereby the electron spin resonance signal is indicative of molecular changes in the fluid sample resulting from fluid degradation during operation of the machinery. - View Dependent Claims (2, 3, 4)
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5. An electron spin resonance spectrometer for in situ measuring of the degradation of operating machinery fluids, comprising:
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an RF microwave cavity resonator having inlet and outlet passages for continually passing a sample of such fluid through the RF microwave cavity resonator during microwave resonating thereof and during the application therethrough of a swept uniform magnetic field;
wherein the fluid sample has a magnetic susceptibility and application of the swept uniform magnetic field causes a magnetic resonance that effects changes in the magnetic susceptibility of the sample at a RF frequency depending on a Zeeman field at the sample,means for modulating a modulation magnetic field, correspondingly to vary the resonant magnetic susceptibility and said magnetic resonance in the fluid sample, which results in at least one of an RF phase modulation and an amplitude modulation; and means for measuring the resulting RF phase modulation or amplitude modulation thereof to derive an electron spin resonance signal, whereby the electron spin resonance signal is indicative of molecular changes in the fluid sample resulting from fluid degradation during operation of the machinery. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method of using electron spin resonance spectrometry for measuring a degradation of lubricating fluids during operation of a vehicle, the method comprising acts of:
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continuously passing a sample of such fluid through a resonating RF microwave cavity resonator during the application therethrough of a swept uniform magnetic field that is modulated, and measuring a resulting phase modulation or amplitude modulation thereof to derive an electron spin resonance signal that is indicative of molecular changes in the fluid sample resulting from fluid degradation during operation of the vehicle.
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Specification