Accurate measurement of concentration for a gas component in a gas mixture in which other components affect determination of the concentration

摘要

Sensor and method for nondispersive analysis of gas mixtures to determine the content of a gas component in it whose absorbance can be affected by other components in the gas mixture GG by collision-expansion. The arrangement includes a measurement chamber 5 that contains the gas mixture being analyzed, a radiation source 4 that emits radiation 15 through the measurement chamber, detectors 10, 14, 16 that receive radiation passed through the measurement chamber, as well as optical band pass filters 9a-c placed between the detectors and radiation source, the detectors being coupled to measurement channels 1-3 or measurement periods. In addition, the arrangement includes an optical gas filter 11 that contains said gas component or a mixture of it and lies between the detectors and radiation source. A first signal S1 is attained from the first measurement channel and a second signal S2 is also obtained from the second measurement channel from the radiation passed through the optical gas filter. Before the analyses the pressure and/or absorption length are determined or alternatively in the gas mixture as effective amount of gas component either with its fixed concentration and/or the pressure and/or absorption length L2 of the mixture at such a value that the second signal S2 and the first signal S1 are linearly independent of each other and the second signal and the first signal have a mutual relation in which the variables are represented by at least the collision expansion and gas component content and in which the coefficients are determined experimentally before the analyses for accurate determination of the effect of collision expansion. IMAGE