Abstract: A spectrophotometer sample cell is described having a housing defining a frusto-conical chamber with inlet and outlet windows at each end. The inlet window is positioned toward the energy source of the spectrophotometer and the outlet window, which is the larger diameter window, is positioned toward the detector assembly of the spectrophotometer. A single outlet passage is positioned between a pair of inlet passages, the latter being toward respective ends of the chamber. The interior surface of the sample cell is provided with means for preventing a substantial portion of reflected energy impinging on the sample cell walls from reaching the detector. Such means include irregularities, annular walls, and wavelength absorbing colors. A trough is provided in the bottom of the larger end of the frusto-conical chamber for conveying condensate to the outlet passage.

Abstract: This invention is a filter assembly for preparing gases for an exhaust gas analyzer. A single housing includes at least three filter cavities, an inlet passage and two outlet passages. A coarse filter for filtering particlate matter and for condensate condensation is disposed in the first filter cavity. Condensate from the first cavity drains into the second filter cavity which has disposed therein a fine filter for filtering condensate. An outlet passage is connected to the second filter cavity for withdrawal of the condensate. A fine filter for filtering the exhaust gas is disposable in the third filter cavity which is coupled to the first filter cavity. A second outlet passage connects the third filter cavity to a pump for removal of the gas to be analyzed. The present invention thus provides a multiple filter assembly in a single housing with large fine filter area, minimal void volume, minimal interconnections, and convenient access to the individual filters.

Abstract: A gas analyzer is described comprising a sample cell for containing a gas mixture to be analyzed, a source for producing and directing infrared energy through the sample cell, a rotary filter wheel having at least one filter thereon for passing infrared energy limited to a wavelength band within the characteristic absorption band of a predetermined gas and having a dark level region substantially opaque to infrared energy, a drive for supporting and rotating the filter wheel to successively interpose the filter and the dark level region between the source and the sample cell in the path of the infrared energy directed by the source, a detector for detecting infrared energy passing through the sample cell and producing an electrical signal representative thereof, and a signal processor connected to the detector for producing an output indicating the concentration of the predetermined gas in the sample cell by comparing the electrical signals produced by the detector with the filter positioned in the infrared e

Abstract: An adaptor assembly is described for sampling gas in an airway tube attached to a patient. The adaptor assembly employs a filter arrangement in a subassembly which extends transversely of the axis of the patient's airway and maximizes the ratio of the effective filter area to the dead volume added by the adaptor assembly to the sampling system.