Method and arrangement for measuring the optical absorptions of gaseous mixtures
First Claim
1. An arrangement for measuring a gas of interest by its optical absorption characteristics, comprising:
- a source of electromagnetic radiation;
means for conditioning such electromagnetic radiation such that it passes through such gas of interest;
means for electrically modulating such electromagnetic radiation that has passed through such gas of interest, said modulating means including a birefringent etalon having associated therewith, a periodic spacing equal to the periodicity of the absorption lines associated with such gas of interest;
said modulating means being further effective for varying an electrical field applied to said birefringent etalon between first and second predetermined strengths such that the periodic transmission spectrum is shifted between spectra which coincide substantially with such absorption lines and spectra which fall between such absorption lines; and
means for detecting at least the intensity of such periodic transmission spectra following passage through such gas of interest and determining therefrom at least an amount of such gas of interest present.
2 Assignments
0 Petitions
Accused Products
Abstract
A gas analyzer arrangement for detecting the presence or quantity of a gas of interest includes a source of electromagnetic radiation for directing a light beam through a light conditioning device such that the light beam is collimated into a parallel beam of light. The conditioned light beam is then directed through a gas sample cell which contains a sample of the gas of interest. The gas of interest has associated therewith, vibrational rotational absorption lines specific to that gas and which are effective for altering the light beam according to the absorption characteristics thereof. The altered light beam is then directed to a birefringent etalon device which has been sized specifically to match those absorption lines of the gas of interest. An electro-optical modulator device associated with the birefringent etalon modulates the absorption lines between the transmission spectra maxima and a point between the transmission spectra maxima so that an absorption ratio can be utilized to determine the presence or quantity of the gas of interest.
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Citations
24 Claims
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1. An arrangement for measuring a gas of interest by its optical absorption characteristics, comprising:
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a source of electromagnetic radiation; means for conditioning such electromagnetic radiation such that it passes through such gas of interest; means for electrically modulating such electromagnetic radiation that has passed through such gas of interest, said modulating means including a birefringent etalon having associated therewith, a periodic spacing equal to the periodicity of the absorption lines associated with such gas of interest; said modulating means being further effective for varying an electrical field applied to said birefringent etalon between first and second predetermined strengths such that the periodic transmission spectrum is shifted between spectra which coincide substantially with such absorption lines and spectra which fall between such absorption lines; and means for detecting at least the intensity of such periodic transmission spectra following passage through such gas of interest and determining therefrom at least an amount of such gas of interest present. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An arrangement for measuring a gas of interest by its optical absorption characteristics, said measuring arrangement comprising:
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a source of electromagnetic radiation; means for directing such electromagnetic radiation through such gas of interest; a first light signal, emerging from passage through such gas of interest, has associated therewith, periodic transmission spectra representative of the absorption lines of such gas of interest; an interferometric device receptive of said first light signal and having associated therewith, a periodic spacing equal to the periodicity of the absorption lines of such gas of interest; means for varying an applied electric field of first and second predetermined strengths to said interferometric device so as to modulate such periodic spacing of said interferometric device between transmission spectra which substantially coincide with such absorption lines and transmission spectra which fall between such absorption lines; and
,means for detecting at least an amount of such gas of interest as a function of the intensity of such periodic transmission spectra following passage through such gas of interest. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method for measuring a gas of interest by its optical absorption characteristics, said measuring method comprising the steps of:
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directing a light beam through a quantity of such gas of interest such that a light signal representative of the absorption lines of the gas of interest is generated thereby; passing said light signal through a birefringent etalon device which has associated therewith, a periodic spacing substantially equivalent to such absorption lines associated with such gas of interest; applying an electrical field at two distinct field strengths to the birefringent etalon to modulate its transmission spectra from wavelengths which substantially coincide with the absorption lines of the gas of interest and wavelengths which fall between such absorption liens; and determining at least an amount of such gas of interest as a function of the relationship such spectra which coincide with such absorption lines and such spectra which fall between such absorption lines. - View Dependent Claims (19)
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20. An arrangement for measuring a gas of interest by its optical absorption characteristics, said measuring arrangement comprising:
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a source of electromagnetic radiation; means for directing such electromagnetic radiation through such gas of interest; a first light signal, emerging from passage through such gas of interest, has associated therewith, periodic transmission spectra representative of the absorption lines of such gas of interest; means for modulating said first light signal between transmission spectra which substantially coincide with such absorption lines and transmission spectra which fall between such absorption lines; an interferometric device receptive of said first light signal and having associated therewith a periodic spacing equal to the periodicity of the absorption liens of such gas of interest, said interferometric device further having associated therewith, a second periodic spacing substantially equivalent to such transmission spectra which fall between such absorption lines; said interferometric device being shifted from said periodic spacing to said second periodic spacing by application of an electrical field thereto; and means for detecting at least an amount of such gas of interest as a function of the intensity of such periodic transmission spectra following passage through such gas of interest. - View Dependent Claims (21, 22, 23, 24)
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Specification