Abstract: A detector for an IR analyzer is disclosed, wherein the blank sample (that is, a quantity of the compound which is searched in a liquid or gaseous sample in which the component is searched for) is replaced by an optical filter, preferably an interference filter. A combination of reflecting walls for the instrument casing and the inner body is also disclosed, the assembly being completed by a window for the flow of the IR radiations and by two thermistors inserted in a Wheatstone bridge circuitry, the unbalances of which are exploited both for detecting the presence of the searched for component and for measuring its concentration by comparison.

Abstract: This invention relates to an improved infrared analyzer, wherein the total radiant energy reaching the detector is maintained at a constant value independently from the aging of the source of radiant energy or the soiling of the sample cell. According to the invention, the improved infrared analyzer comprises a comparator, whose outlet feeds the radiant energy source and whose inlets receive a reference signal of constant value and, respectively, a signal which varies as a function of the total radiant energy received and measured by the detector.