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1. (WO2018060479) THERMAL CONDUCTIVITY DETECTOR FOR GAS MIXTURES HAVING AT LEAST THREE COMPONENTS

Pub. No.:    WO/2018/060479    International Application No.:    PCT/EP2017/074871
Publication Date: Fri Apr 06 01:59:59 CEST 2018 International Filing Date: Sat Sep 30 01:59:59 CEST 2017
IPC: G01N 33/00
G01N 25/18
Applicants: SIEMENS AKTIENGESELLSCHAFT
Inventors: LUDWIG, Michael
MARCAUX, Günter
Title: THERMAL CONDUCTIVITY DETECTOR FOR GAS MIXTURES HAVING AT LEAST THREE COMPONENTS
Abstract:
Gas analyzer for a gas mixture (6) having three or more components, having – a channel (3) carrying the gas mixture (6), – a thermocouple probe (1) having a measurement point (2) inside the channel (3) and a comparison point (4) in thermal contact with the wall of the channel (3), – a control device (7) for pulsed actuation of the thermocouple probe (1) with current impulses (8), – a measuring device (9) for measuring the voltage at the comparison point (4) of the thermocouple probe (1) in the pauses between the current impulses (8) and – an evaluation device (10) for ascertaining the temperature difference between the measurement point (2) and the comparison point (4) from the measured voltage and for computing the ratio of the components of the gas mixture (6) from temperature difference values ascertained for at least two different times in each pause, – wherein the control device (7) generates current impulses (8) having at least two different energy contents and the temperature difference value that is recorded by the evaluation device (10) at the first time in the pause after a current impulse (8) having a larger energy content and that is used for the computation is higher than in the case of a current impulse (8) having a smaller energy content.