Infrared gas mixture analyzer
First Claim
1. A detector for an infrared gas analyzer, said detector comprising:
- (a) a front detection cell for receiving infrared radiation;
(b) a rear detection cell for receiving infrared radiation from said front detection cell;
(c) a gas flow sensor communicating with said front and rear detection cells; and
(d) an auxiliary chamber in fluid communication with said front detection cell.
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0 Petitions
Accused Products
Abstract
A pneumatic detector, non-dispersive infrared analyzer employing detector cell chambers in optical series. The invention having an auxiliary chamber communicating with the front chamber to increase the rear chamber'"'"'s signal so as to balance the signals from the front and rear chambers. The use of xenon as a diluent gas in the detector chambers in combination with a mass flow detector to improve the sensitivity. The use of an improved synchronous detection method employing a voltage-to-frequency circuit to convert the detector signal to a synchronous high resolution digital signal. The use of an improved source electrically pulsed having low thermal mass and a large radiating area.
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Citations
14 Claims
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1. A detector for an infrared gas analyzer, said detector comprising:
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(a) a front detection cell for receiving infrared radiation; (b) a rear detection cell for receiving infrared radiation from said front detection cell; (c) a gas flow sensor communicating with said front and rear detection cells; and (d) an auxiliary chamber in fluid communication with said front detection cell. - View Dependent Claims (2, 3, 4, 5)
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6. A detector for an infrared analyzer, said detector comprising:
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(a) a front detection cell receiving infrared radiation; (b) a rear detection cell receiving infrared radiation from said front detection cell; and (c) a flow sensor fluidly connected between said front and rear detector cells; and (d) xenon gas mixed with a sensitizing gas having substantially similar infrared absorption spectra to that of a gas being analyzed disposed within said front and rear detection cells.
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7. An infrared analyzer comprising:
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a) a sample cell for containing a sample gas to be analyzed; b) a pulsed infrared radiation source disposed adjacent one end of said sample cell; c) a detector disposed adjacent the opposite end of said sample cell for measuring the infrared radiation radiated through said sample chamber, said detector comprising; i) a front detection cell receiving infrared radiation; ii) a rear detection cell receiving infrared radiation from said front detection cell; and iii) a balancing chamber in fluid communication with said front detection cell for controlling expansion of gas within said front detection cell; and d) a linearization circuit for linearizing the output of said detector such that an output of the linearization circuit corresponds to the concentration of a desired gas in the sample gas, said linearization circuit comprising; i) a voltage-to-frequency converter; ii) a look-up table containing concentration values corresponding to detector outputs; and iii) a microprocessor for looking up the concentration in said look-up table corresponding to an output of said detector.
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8. An infrared analyzer comprising:
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(a) a sample cell for containing a sample gas to be analyzed; (b) a infrared radiation source; and (c) a detector for measuring the infrared radiation radiated through said sample cell, said detector comprising; (i) a front detection cell receiving infrared radiation; (ii) a rear detection cell receiving infrared radiation from said front detection cell; and (iii) a flow sensor fluidly connected between said front and rear chambers, an auxiliary chamber fluidly connected with said front chamber, said auxiliary chamber'"'"'s volume selected to approximately balance the flow signals produced by said front and rear chambers and sensed by said flow sensor. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An infrared analyzer comprising:
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a) a sample cell for containing a sample gas to be analyzed; b) a pulsed infrared radiation source disposed adjacent one end of said sample cell; c) a detector disposed adjacent the opposite end of said sample cell for measuring the infrared radiation radiated through said sample chamber, said detector comprising; i) a front detection cell receiving infrared radiation; ii) a rear detection cell receiving infrared radiation from said front detection cell; and iii) a balancing chamber in fluid communication with said front detection cell for controlling expansion of gas within said front detection cell; and d) a linearization circuit for linearizing the output of said detector such that an output of the linearization circuit corresponds to the concentration of a desired gas in the sample gas, said linearization circuit comprising a linearization means for defining a polynomial which relates detector outputs to concentrations of a gas being analyzed.
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Specification