Abstract: A filter probe for sampling components of a stack gas which includes means for extracting a flow sample of the stack gas, means for inertial filtering of the flowing stack gas sample extracted by the extracting means, means for collecting the flowing stack gas sample after filtering by the filtering means, means for conditioning the filtered and collected stack gas sample based on predetermined criteria such as cooling and drying, and means for flowing the filtered and collected stack gas sample from the collecting means to the extracting means so that a constant flow of the filtered stack gas sample is presented to the conditioning means to permit essentially instantaneous analysis of the stack gas sample.

Abstract: An optical fluid analyzer uses the extent of optical, preferably infrared absorption of a fluid to be analyzed to determine the concentration of a selected constituant of the fluid. A first detector detects light after absorption by the fluid at a wavelength at which the selected constituant has a characteristic absorption for conversion into an electrical signal indicating the concentration of the selected constituant and a background from absorption of other constituants of the fluid for a measurement processing channel. A second detector correspondingly converts light after absorption by the fluid, but at a different wavelength at which the absorption at least approximates the background absorption alone for a neutral processing channel.

Abstract: An optical gas-concentration analyzer which utilizes the infrared absorption principle has a sample chamber and reference chamber with infrared source and detector assemblies spaced at opposite ends of an in alignment with the chambers. An electronic processing system utilizes a spectral-absorption electrical signal from the detector assembly to derive the desired gas-concentration measurement for readout from a display device. Barometric correction means is provided to permit on site calibration by the user of the gas analyzer via an atmospheric pressure calibration indication obtained on the display device by switching the apparatus to a calibrating mode. Apparatus for compensating for broadening of the spectral line of a gas the concentration of which is to be measured by another gas in the sample and for the temperature of the sample gas is also provided.

Abstract: An optical gas analyzer is disclosed utilizing the infrared absorption principle having a sample chamber and reference chamber with infrared source and detector assembly spaced at opposite ends of and in alignment with the chambers with baffle means provided in cooperating relation with the infrared source to prevent cross-currents with respect thereto and masking means provided in cooperating relation with the detector assembly to mask out a gas having a partially overlapping infrared absorption band. The electronic processing system utilizes the total area under the signal waveform to derive the desired measurement. In addition barometric correction means is provided to permit on site calibration by the user of the gas analyzer.

Abstract: A multiple gas analyzer is disclosed utilizing the infrared absorption principle for determining the quantity of two or more gases with a sample tube and a reference tube in parallel orientation with an infrared source between one end of the two tubes, and an infrared detector assembly between the other end of the tubes. Immediately opposed to each end of the tubes are a pair of mirrors, one being a transmitting mirror remote from the infrared source and directing the infrared beam in parallel paths through the reference tube and sample tube, and a receiving mirror opposite the infrared detector assembly to focus the infrared beam after passing through the tubes on to the infrared detectors.