Contaminated sample gas analyzer and gas cell therefor

摘要

A gas analyzer for performing gas analysis on a sample gas containing contaminants which normally interfere with the operation of the analyzer is disclosed comprising a source of radiant energy; means for directing radiant energy through a sample gas; a disposable gas cell; a detector for receiving radiant energy; and a circuit for analyzing the output of the detector and indicating the concentration of predetermined constituents in the sample gas. The gas cell comprises a disposable sample gas cell having a sample enclosure for containing a sample gas volume; sample windows defining a portion of a sample gas optical path extending from the source of radiant energy through the sample gas volume to the detector; an inlet for supplying sample gas to the sample gas volume and an outlet for exhausting sample gas from the sample gas volume. The disposable sample cell is provided with inlet and exhaust manifolds having cross-sectional areas that minimize dead space and insure laminar flow, minimizing stagnant areas. Specifically, the cross-sectional areas of the inlet and outlet manifolds are relatively constant, the cross-sectional area of the outlet being larger than the cross-sectional area of the inlet, and the inlet and outlet manifolds vary in cross-sectional shape from elongate shapes proximate the windows to a shape having roughly equilateral dimensions distal to the windows. The analyzer and the gas cell are provided with a number of inter-related features that make the analyzer self aligning and eliminates the necessity of recalibrating the analyzer each time a sample cell is replaced.