Patent ID: 6818895
Filing Date: 2004-11-16
Classification: G01J,G01N

Abstract:
An infrared gas analyzer comprising:(a) an infrared source for emitting infrared energy; (b) a sample cell for containing gases to be analyzed positioned to be in the path of infrared energy emitted by said source; (c) a detector assembly comprised of a housing, a base, at least first, second and third thermopile detectors supported on said base, and an infrared transparent window on the opposite side of said detectors from said base, said base, detectors and window being in close thermal proximity to each other and being responsive to impinging infrared energy to produce an electrical response, said detector assembly being unitary and detachably mounted in said infrared gas analyzer, said first and second detectors being positioned in the path of infrared energy emitted by said source, and (d) a wavelength narrow band filter corresponding to an absorption band for each of the gases of interest and a narrow band reference filter corresponding to a reference band, each of said narrow band filters being positioned outside of said detector assembly and between said detector assembly and said infrared source in the path of infrared energy emitted by said source on a respective one of said first and second detectors, said third detector being positioned outside of the path of infrared energy emitted by the source and out of alignment with any of laid narrow band filters, whereby the electrical response generated by said third detector may be subtracted from the electrical responses generated by said first and second detectors to achieve thermal stablization.