Gas Research Institute

Operations Technology Development, Nfp

American Intell-sensors Corporation

Harold S Lessure

Satoru Simizu

Alberto M Guzman

Louis J Denes

Richard P Kunkle

Kirankumar M Kothari

Richard A Evans

Dale M Matuza

A method and apparatus in which a first absorption measurement is made over a first frequency interval or set of frequency intervals including one or more absorptions from a spectral band of interest. The first absorption measurement is ideally selected to be near the frequency of a peak in the absorption spectrum, providing high sensitivity at low gas concentrations. A second absorption measurement is made over a second frequency interval. The second absorption measurement is made to include a contribution from the broadening of the absorption spectrum at higher concentrations. The second absorption measurement provides sensitivity at higher concentrations. The two absorption measurements are then combined to deduce the target sample concentration as the absorption line spectrum changes shape with concentration.

Wide concentration range gas detection

An assembly and method provide sensitive high speed spectroscopic gas detection via the use of a non-collimated convergent light path through a birefringent crystal in a birefringent filter design to allow improved light collection and a reduction in the number of optical elements required to produce a useful absorption signal for the detection of gases.

Method and assembly for gas detection via a convergent birefringent filter

An infrared gas analyzer for measuring low concentrations of a target gas, on the order of parts per million, in a sample gas is comprised of a gas sampling chamber, an infrared light source, and a power source for energizing the light source. A plurality of filters is provided to transmit infrared radiation at certain wavelengths. The wavelengths are chosen such that the effects of unwanted gases (such as water and carbon dioxide) can be removed from the final output signal. A plurality of infrared detectors are responsive to the filters for producing a plurality of electrical signals. A circuit is provided for combining the plurality of electrical signals to produce an output signal representative of the concentration of the target gas independently of other gases in the sample gas. A method of measuring low concentrations of a target gas is also disclosed.

Non-dispersive infrared gas analyzer with interfering gas correction

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Pittsburgh, PA, United States of America

Harold S Lessure