Multichannel gas analyzer and method of use

An optical bench, comprising:

• (a) a gas pathway through the optical bench, with the gas pathway having an inlet means for adapting the cross-sectional shape of a sample gas stream being input to the gas pathway to the cross-sectional shape of the gas pathway,
• (b) at least one detection channel assembly disposed along the gas pathway that has an optical path through the gas pathway and reference means for generating reference signals, with the detection channel assembly including an energy source for emitting energy capable of being absorbed at least by a gas of interest in the sample gas stream, filter means for transmitting therethrough energy at wavelengths capable of being absorbed by the gas of interest, detector means capable of generating an output signal in proportion to an amount of energy issuing on the detector means from the filter means, and chopping means for during discrete periods causing energy to issue on the detector means for detecting the absorption by the gas of interest in the sample gas stream;
• (c) timing means for generating cycle timing signals for use in timing detection events and processing of signals generated by the detector means;
• (d) temperature sensing means for measuring the temperature within the optical bench,
• (e) pressure measuring means for measuring the pressure within the gas pathway;
• (f) storage means for storing information for characterizing components of the optical bench;
• and
• (g) circuitry for processing signals generated by the detector means relative to signals generated by the reference means, the timing means, the temperature sensing means, and the pressure sensing means, and for processing signals from the storage means that are representative of the information for characterizing the components of the optical bench.

A gas analyzer apparatus, comprising:

• (a) an optical bench, further comprising,
• (1) a gas pathway through the optical bench, with the gas pathway having an inlet means for adapting the cross-sectional shape of a sample gas stream being input to the gas pathway to the cross-sectional shape of the gas pathway,
• (2) at least gas one detection channel assembly disposed along the gas pathway that has an optical path through the gas pathway and reference means for generating reference signals, with the detection channel assembly including an energy source for emitting energy capable of being absorbed at least by a gas of interest in the sample gas stream, filter means for transmitting therethrough energy at wavelengths capable of being absorbed by the gas of interest, detector means capable of generating an output signal in proportion to an amount of energy issuing on the detector means form the filter means, and chopping means for during discrete periods causing energy to issue on the detector means for detecting the absorption the gas of interest in the sample gas stream,
• (3) timing means for generating cycle timing signals for use in timing detection events and processing of signals generated by the detector means,
• (4) temperature sensing means for measuring the temperature within the optical bench,
• (5) pressure measuring means for measuring the pressure within the gas pathway,
• (6) storage means for storing information for characterizing components of the optical bench, and
• (7) circuitry for processing the signals generated by the detector means relative to signals generated by the reference means, the timing means, the temperature sensing means, and the pressure sensing means, and for processing signals from the storage means that are representative of the information for characterizing the optical bench components;
• (b) fluid flow control means including at least first pump means for drawing the sample gas stream through the gas pathway at a predetermined rate and flow sensing means for measuring flow rate of the sample gas stream through the gas pathway;
• (c) analog signal processing circuitry further comprising,
• (1) analog input circuits for receiving signals output from the optical bench, processing these signals and converting them from analog to digital signals,
• (2) signal processing circuits for receiving the digital outputs from the analog input circuits and correcting the signals indicative of the partial pressure of the gas of interest in the gas pathway for temperature, collision broadening, cross-correction, pressure in the gas pathway, and characterization of the optical bench components, and
• (3) output circuit for providing at least the corrected signals for the partial pressure of the gas of interest in the gas pathway to display processing circuitry;
• and
• (d) display processing circuitry for receiving the digital signals output from the analog signal processing circuitry, processing the signals, and generating signals for controlling the display of information or a display means, for output from the apparatus, and for activation of alarm means when appropriate.