Importance

Loading Importance Indicators...

Abstract

A calibration method for gas concentration measurement with an NDIR technique based on optical absorption. Radiation is imposed onto the gas mixture under measurement contained in a measurement channel (3) isolated at least partially from its environment, the intensity of radiation transmitted through the gas is measured, the gas concentration is computed from the measured intensity, in order to calibrate the measurement apparatus the gas state variables are deviated in a controlled manner, whereby the level of transmitted radiation intensity is changed, and the intensity of the transmitted radiation is measured in at least two known points of the gas state variables, thus obtaining data for calibration of the measurement apparatus employed. The gas state variables are deviated by heating the gas under measurement in such a short time during which the ambient concentration of the gas undergoes no change, whereby the gas density is decreased with the increasing temperature, while the partial pressure of the gas under measurement stays essentially constant.

Loading the Abstract Image...

First Claim