Improvements in the apparatus for the continuous dosage in a gas of small quantities of a substance capable of absorbing a well defined region of the spectrum issued by a suitable luminous source. (Machine-translation by Google Translate, not legally binding)

摘要

Improvement in the apparatus for the continuous dosing in a gas of small quantities of a substance capable of absorbing a well-defined region of the spectrum emitted by an appropriate light source and comprising, at least, an absorption chamber covered by the gas to be analyzed and two photoelectric cells integrated in a measurement bridge whose measuring device has a negligible consumption compared to the photoelectric cell current, said measurement bridge being regulated in such a way as to indicate zero when the chamber is powered by a sample of gas free of the substance to be dosed and whose sensitivity is adjusted initially by feeding the chamber by means of a sample of gas containing a known quantity of the substance to be dosed, said improvement being characterized in that periodically the absorption chamber is fed only by a sample of gas free of substance to be dosed, and because: eventual regulation is the zero of the measuring device; the sensitivity is readjusted by simulating a variation of illumination of the photoelectric measuring cell, by moving the connection point of the measuring device to the resistance in series with said cell, in order to apply a voltage at the input of said measuring device. Reference directly proportional to the intensity of the current that passes through the measurement cell, which causes an unbalance of the bridge, which is detected by the measuring device whose sensitivity is adjusted to indicate a graduation corresponding to the simulated illumination variation. (Machine-translation by Google Translate, not legally binding)