Patent ID: 6844554

Claim:
A method for non-dispersive analysis of gas mixtures for determining the concentration of a first gas component in a gas mixture, the first gas component having absorbance properties which may be influenced by other gas components of said gas mixture, said method comprising the steps of: (A) providing a radiation source emitting radiation over a wavelength range along a radiation path through the gas mixture; (B) providing to said radiation path a first optical bandpass filter having a first transmission band within an absorption band of said first gas component; (C) detecting a first intensity of radiation that has passed along said radiation path and through said first optical bandpass filter, the first intensity of radiation producing a first measurement signal when the gas mixture in the radiation path is the gas mixture to be analyzed; (D) providing to said radiation path a second optical bandpass filter having a second transmission band; (E) detecting a second intensity of radiation that has passed along said radiation path and through said second optical bandpass filter, the second intensity of radiation producing a second measurement signal when the gas mixture in the radiation path is the gas mixture to be analyzed; (F) determining a concentration value for the first gas component in the gas mixture to be analyzed using a predetermined formula or predetermined formulas, employing as inputs at least said first measurement signal and said second measurement signal; and (G) selecting the second transmission band so that it is substantially or entirely outside the absorption bands of said first gas component and so that it comprises an absorption band of a certain second gas component causing a distortion in the absorption band of said first gas component, the radiation absorption occurring in the absorption band of the second gas component being substantially less than the radiation absorption occurring in the absorption band of the gas component.