CALIBRATION METHOD FOR GAS CONCENTRATION MEASUREMENTS

A NDIR gas concentration measurement method based on optical absorption. Radiation from a source 2, 9 is transmitted through the gas mixture under measurement, contained in a measurement channel (3) isolated at least partially from its environment, the intensity of radiation received at a detector 4...

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Bibliographic Details
Main Author ARI LEHTO
Format Patent
LanguageEnglish
Published 04.08.1993
Subjects
INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES
MEASURING
PHYSICS
TESTING
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Summary:A NDIR gas concentration measurement method based on optical absorption. Radiation from a source 2, 9 is transmitted through the gas mixture under measurement, contained in a measurement channel (3) isolated at least partially from its environment, the intensity of radiation received at a detector 4, 11 is measured and used to compute gas concentration. To calibrate the measurement apparatus the gas state variables are deviated by rapidly heating the gas under measurement such that the ambient concentration of the gas undergoes no change, gas density is decreased with the increasing temperature, but the partial pressure of the gas under measurement stays essentially constant. The intensity of transmitted radiation is measured at at least two values of the gas state variables. Heating of the measurement channel 3, 10 may be effected by a resistive conductor 6 wound around the channel.
Bibliography:Application Number: GB19930000384