Figure 4 : Comparison Of Spectra; Figure 5 : Transmissivity Of Co - CODEL Energy Tech 401 Installation, Operation And Maintenance Manual

Section 2
General Description

Figure 4 : Comparison of Spectra

2.2.5.3 Transmissivity of CO The transmission through the gas of the IR energy at about 4.7µm is affected by
Within the 4.7µm Band the concentration of CO. Figure 5 illustrates how the energy within the selected
band varies with CO concentration.

Figure 5 : Transmissivity of CO

The shape of this curve is fixed by the characteristics of the 4.7µm filter - it
cannot change, and the curve is practically flat at CO concentrations of above
10,000 ppm.metres. A cross-duct monitor effectively measures CO molecules in
its optical path, so the same concentration of CO will have a greater effect across
a large measurement path than a small measurement path. The term
ppm.metres is the concentration of CO within the duct multiplied by the gas path
length over which it has been measured.
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Issue: A Revision: 1 Date: 24/07/19 Ref: 100606