Patent ID: 8143581

Claim:
A Non-Dispersive Infrared (“NDIR”) gas sensor for detecting the presence of a chosen gas, comprising: a single infrared source for generating infrared radiation into a sample chamber to illuminate a signal channel path length and a reference channel path length; a signal detector located in the signal channel path length; a reference detector located in the reference channel path length; and electronics for determining a sample concentration of the chosen gas; wherein each of the reference detector and the signal detector have an identical narrow band pass filter with the same Center Wavelength (“CWL”), Full Width Half Maximum (FWHM) and transmittance efficiency at the CWL; wherein the electronics is calibrated by use of a calibration curve generated by using a normalized ratio of signal to reference outputs that starts at unity when there is zero concentration of the chosen gas; wherein the calibrated electronics determines a sample concentration of the chosen gas in the sample chamber by use of an absorption bias between a signal output of the signal detector and reference output of the reference detector obtained solely from use of the single infrared source; and wherein the single infrared source is the only source of infrared radiation emitted into the sample chamber.