Optical oxygen concentration monitor
First Claim
1. A system for determining the concentration of oxygen in an environment of interest, the system including:
- A. an argon discharge lamp for selectively supplying to the environment of interest light in a spectral line having a wavelength of approximately 763.5 nm, which is close to a spectral absorption line of oxygen; and
B. means for determining the concentration of oxygen in the environment of interest based on variations in optical flux in the light supplied by the lamp to the environment of interest.
2 Assignments
0 Petitions
Accused Products
Abstract
A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen'"'"'s A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest.
15 Citations
13 Claims
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1. A system for determining the concentration of oxygen in an environment of interest, the system including:
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A. an argon discharge lamp for selectively supplying to the environment of interest light in a spectral line having a wavelength of approximately 763.5 nm, which is close to a spectral absorption line of oxygen; and B. means for determining the concentration of oxygen in the environment of interest based on variations in optical flux in the light supplied by the lamp to the environment of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for determining the concentration of oxygen in an environment of interest, the system including:
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A. an argon discharge lamp for supplying light to the environment of interest; B. a magnetic field source for supplying a magnetic field that splits the light supplied by the lamp into a set of upshifted components with wavelengths that are readily absorbed by an oxygen absorption spectral line and a set of downshifted components with wavelengths that are not as readily absorbed by the oxygen absorption line; C. control means for selectively controlling the magnetic field source to provide a magnetic field of one polarity or a reverse polarity, the polarity of the magnetic field determining the circular polarizations of the sets of upshifted and downshifted components; D. a circular polarizer for selectively passing to the environment of interest the set of upshifted components or the set the downshifted components, depending on the orientations of the circular polarizations; and E. means for determining the concentration of oxygen in the environment of interest based on variations in the transmitted optical flux of the argon line when the set of upshifted components is supplied to the environment of interest.
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12. A system for determining the concentration of oxygen in an environment of interest, the system including:
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A. an argon discharge lamp for supplying light to the environment of interest; B. a magnetic field source for supply a magnetic field that splits the light supplied by the lamp into a set of upshifted components with wavelengths that are readily absorbed by an oxygen absorption spectral line and a set of downshifted components with wavelengths that not as readily absorbed by the oxygen absorption line; C. control means for selectively turning on the magnetic field source and turning off the magnetic field source; D. means for determining the concentration of oxygen in the environment of interest based on variations in the transmitted optical flux of the argon line between (i) the sets of upshifted and downshifted components being supplied to the environment of interest when the magnetic field source is turned on, and (ii) unshifted light being supplied to the environment of interest when the magnetic field source is turned off.
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13. A system for determining the concentration of oxygen in an environment of interest, the system including:
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A. an argon discharge lamp for supplying light to the environment of interest; B. a magnetic field source for supplying a magnetic field to the environment of interest, the magnetic field splitting an oxygen spectral line into a set of downshifted components with wavelengths that readily absorb a spectral line in the light produced by the argon lamp and a set of upshifted components with wavelengths that do not as readily absorb the spectral line; C. control means for selectively turning on the magnetic field source and turning off the magnetic field source; D. means for determining the concentration of oxygen in the environment of interest based on variations in the transmitted optical flux of the light between times when (i) the magnetic field source is turned on and sets of upshifted and downshifted components are present in the environment of interest, and (ii) the magnetic field source is turned off and unshifted components are present in the environment of interest.
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Specification