Procedure for measuring amounts of chemicals contained in hot furnace gases consists of cooling gas samples and using coherent light signal from diode laser

Taking a sample of the gas to be analyzed, cooling it to a temperature preferably below 200 [deg] C, and then measuring the quantity of chemicals, especially CO and CO 2, contained in it with the aid of a coherent light signal emitted by a tunable diode laser (TDL) through the gas and captured as it emerges. The TDL has a continuously-adjustable wavelength over a range close to infrared and can be used to measure concentrations of e.g. O 2 and H 2O. The procedure consists of taking a sample of the gas to be analyzed, cooling it to a temperature preferably below 200 [deg] C, and then measuring the quantity of chemicals, especially CO and CO 2, contained in it with the aid of a coherent light signal emitted by a tunable diode laser (TDL) through the gas and captured as it emerges. The TDL has a continuously-adjustable wavelength over a range close to infrared, including 1581 nanometers, and can also be used to measure concentrations of other chemicals such as O 2 and H 2O. The gas sample is taken with the aid of an axially symmetrical water-cooled tube incorporating a component that is mobile about its axis of symmetry and can be rotated to remove accumulated impurities from the tube's inner surface. The sampling unit can also be unblocked with the aid of compressed air. Système de décolmatage d'une canne à symétrie axiale de prélèvement d'échantillons dans une veine gazeuse comportant des impuretés. Il comporte une pièce mobile autour de l'axe de symétrie da la canne qui vient décoller les impuretés accumulées sur la paroi interne de ladite canne par rotation relative de la pièce et/ou de la canne autour de l'axe.