Modular gas analyzer

Claim 1

In an infrared gas analyzer including a sample cell for containing the gas mixture to be analyzed, means for directing infrared energy through said sample cell, source means for periodically interrupting the infrared energy at a predetermined frequency, detector means responsive to infrared energy of at least one preselected wavelength for producing a signal having an amplitude proportional to the infrared energy passing through said sample cell and having a frequency corresponding to the predetermined frequency, said preselected wavelength corresponding to the characteristic absorption wavelength of a preselected gas, and signal processing means for processing the signal output of said detector means to produce a signal representative of the concentration of the preselected gas in the mixture being analyzed, the analyzer being a modular construction to facilitate assembly and replacement of components, comprising a modular sample tube, a modular source housing means for mounting the source of infrared energy at one end of said sample tube, a modular detector housing means for mounting the detector means at the opposite end of said tube, a printed circuit board mounting the signal processing means, and a mounting means for supporting said sample tube, source housing means, detector housing means and printed circuit board, said mounting means comprising a unitary structure including a base and a plurality of integral channel members extending transversely from the same side thereof and spaced in pairs to form three substantially parallel pairs of channels for engaging with and locating said source housing means, detector housing means and printed circuit board, respectively, in operative relationship with each other, and detent means for releasably securing said source housing means, detector housing means and printed circuit board in said channel members to enable said source housing means, said detector housing means and said printed circuit board to be readily removed individually for repair or replacement without the need to remove other modular elements.