Patent ID: 7351954

Claim:
A method for detecting gas concentration with infrared absorption characteristics, comprising the following steps: a. feeding gas containing a certain amount of gas to be detected into a detecting chamber in a detecting light path; b. transmitting an infrared light containing a specific wavelength λ through the detecting chamber, so as to generate an infrared light signal reflecting concentration information of the gas to be detected, wherein the gas to be detected has maximum absorption to the infrared light at the specific wavelength λ; c. processing the infrared light signal which passed through the detecting chamber, so as to obtain a measured value C 0 of the concentration of the gas to be detected; and d. computing a calibrated value C of the concentration of the gas to be detected according to a formula C=C 0 *β, wherein β is a calibration factor; wherein the calibration factor β is obtained by a calibration step of: switching a reference chamber filled with a reference gas having a known concentration value C 1 into the detecting light path to replace the detecting chamber, then repeating the step b and the step c to obtain a measured value C 2 of the concentration of the reference gas in the reference chamber, and thus determining the calibration factor β by a formula of β=C 1 /C 2 according to the measured value C 2 and the known concentration value C 1 of the reference gas.