Dragerwerk Aktiengesellschaft

Georg Ankerhold

An optical gas-measuring system and process identifies especially infrared-active individual gases over a measuring path of about m and to determine their concentration averaged over the measuring path swept. The laser source ( ) emits a divergent ray beam, from which both the measuring beam and the reference beam are formed after a single-time reflection of the emitted ray beam. A first radiation reflector ( ) is designed in the form of a first hollow mirror for the reflection of a first part of the ray beam emitted from the laser source ( ) as a measuring beam into the open optical measuring path. A second radiation reflector ( ) is designed in the form of a second hollow mirror for the reflection of a second part of the ray beam emitted from the laser source ( ) as a reference beam into a reference gas cuvette ( ) containing the reference gas sample for the gas to be measured. A third radiation reflector ( ) is designed in the form of a third hollow mirror for the reflection of the measuring beam received after passing through the optical measuring path onto a first radiation detector ( ).

Gas-measuring system

A laser diode gas sensor for the spectroscopic measurement of a gas sample, with a retroreflector and a concave mirror, which define between them an open measuring path with the gas to be analyzed. Laser light passes through the measuring path, is reflected at the retroreflector, and is directed toward a detector via a concave mirror in order to determine the mean concentration of the gas component to be analyzed in the optical measuring path. Optical elements, such as beam splitters, lenses, etc., which lead to losses of intensity, were used before to couple the laser light into the beam path onto the retroreflector, and to decouple the reflected light to the detector. An improved optical imaging array, which minimizes losses, is provided. The concave mirror is provided centrally with an opening transparent to the laser light, through which a weakly divergent bundle of laser light is directed onto the retroreflector, so that the retroreflector is illuminated essentially over its entire surface. The retroreflector is made with a matrix consisting of a plurality of triple mirrors, which reflect the incident, weakly divergent bundle of laser beams as a bundle of laser beams with convergent properties onto the concave mirror. The concave mirror is arranged or shaped such that the laser light reflected by the retroreflector is focused by the concave mirror directly onto the detector, which is arranged outside the principal beam path.

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Lübeck, Germany

Georg Ankerhold