DEVICE AND METHOD FOR DETERMINING THE CONCENTRATION OF AT LEAST ONE GAS IN A SAMPLE GAS FLOW BY MEANS OF INFRARED ABSORPTION SPECTROSCOPY

摘要

The invention relates to devices for determining the concentration of at least one gas in a sample gas flow by means of infrared absorption spectroscopy, comprising an infrared radiation source (12), the radiation of which can be guided through an analysis cell (16), a sample gas flow, which can be conducted into the analysis cell (16), a detector (22), by means of which an absorption spectrum arising in the analysis cell (16) can be measured, and a Peltier cooling element (66) having a hot side (68) and a cold side (70), wherein the cold side (70) is in thermally conductive contact with the infrared radiation source (12) or the detector (22) and the warm side is in thermally conductive contact with a heat sink (46). However, measurement inaccuracies often occur because of thermal noise of the infrared radiation source. In order to prevent such measurement inaccuracies, the heat sink (46) according to the invention is cooled by means of a rotational-speed-controlled fan (38).