Verfahren und Anordnung zum Messen der Konzentration eines Nachweisgases in einem ein Störgas enthaltenden Meßgas

摘要

In order to measure the nitric oxide concentration in a measuring gas containing water vapour by means of NDIR gas analysis, the measuring gas, possibly after water vapour has been partially removed, a zero gas by means of which the zero point is determined and a test gas which contains a known concentration of nitric oxide and with which the extent of the measurement effect is determined, are taken via a humidifier so that all three gases have the same water vapour concentration. After the zero point and the measuring effect have been determined, the interfering effect of the water vapour on the measurement can be eliminated by finding the difference and the use of a correcting calculation. The invention is used in the measurement of nitric oxide in exhaust gases.