초록 ▼

A system for monitoring the concentration level of a gas in a monitored environment, e.g., for monitoring the concentration level of a fire suppression agent in the engine bay and/or cargo bay of an aircraft. The system includes a light source for producing source light, an optical system that direc

A system for monitoring the concentration level of a gas in a monitored environment, e.g., for monitoring the concentration level of a fire suppression agent in the engine bay and/or cargo bay of an aircraft. The system includes a light source for producing source light, an optical system that directs the source light along a plurality of different optical paths having different respective optical path lengths, and a plurality of photodectors that are positioned to receive the source light that traverses different respective ones of the plurality of different optical path lengths, and which produce a plurality of output signals indicative of the concentration level of the gas in the monitored environment. In the preferred embodiment, the system further includes a narrow band spectral filter positioned between the light source and each photodetector, wherein the narrow band spectral filter has a narrow band pass that is matched to a selected optical absorption wavelength of the gas.

대표청구항 ▼

[ What is claimed is:] [1.] A system for monitoring the concentration level of a gas in a monitored environment, comprising:means for producing light;means for directing the light along a plurality of different optical paths having different respective optical path lengths;means for filtering the li

[ What is claimed is:] [1.] A system for monitoring the concentration level of a gas in a monitored environment, comprising:means for producing light;means for directing the light along a plurality of different optical paths having different respective optical path lengths;means for filtering the light to pass only a prescribed spectral band which includes an optical absorption wavelength of the gas;means for detecting the filtered light that traverses each different optical path length, and for producing a plurality of output signals indicative of the concentration level of the gas in the monitored environment;wherein the means for producing light includes a cylindrical optical source;wherein the means for directing includes a plurality of photodetectors that are positioned to receive the filtered light that traverses different respective ones of the plurality of different optical path lengths; and,wherein the means for directing the light includes:a multi-windowed rotating optical chopper that contains the optical source and produces a repeating sequence of light pulses that traverse successive ones of the plurality of different optical path lengths;a mirror;a detector mask that is positioned between the mirror and the plurality of photodetectors; and,wherein the detector mask includes a substrate that is transparent to the optical absorption wavelength of the gas, the substrate having a first major surface coated with a reflective material and having a plurality of apertures aligned with respective ones of the plurality of photodetectors, wherein the mirror and the reflective material of the first major surface of the substrate, in combination, reflect the sequential light pulses to traverse the plurality of different optical path lengths.