Patent ID: 6862535

Claim:
A spectroscopic toxic gas monitoring system for detection of one or more toxic gas species in a fluid environment containing or susceptible to presence of same, said system comprising: a spectroscopic monitoring assembly including a gas flow path, a spectroscopic cell in gas flow communication with the gas flow path, an infrared radiation source, an interferometer arranged in receiving relationship to the infrared radiation source to modulate infrared radiation and transmit correspondingly modulated infrared radiation through the spectroscopic cell for absorption of the correspondingly modulated infrared radiation characteristic of said toxic gas species when present in gas flowed through said spectroscopic cell, a detection unit arranged in relation to said spectroscopic cell to receive non-absorbed radiation therefrom and produce a corresponding digitized spectrum for analysis; means for sampling the fluid environment and delivering samples therefrom to said gas flow path for flow to the spectroscopic cell; and a computational assembly (i) including a stored signal-to-noise ratio reference, and a stored background spectrum for the fluid environment when the toxic gas species is not present therein, and (ii) arranged to analyze the digitized spectrum and responsively produce an output indicative of quantitative presence of the toxic gas species in the fluid environment, in an analysis procedure comprising continuous measurement of the quality of a background spectrum of a monitored spectral region for said fluid environment, and determination of: (a) signal-to-noise ratio from signal and noise characteristics of said digitized spectrum, and deviation from the stored signal-to-noise reference; (b) a background spectrum for the monitored fluid environment excluding the toxic gas species, if any, therein, and deviation from the stored background spectrum; and (c) total detection signal for the detection unit.