Optical Waveguide Sensor for Methane Gas.
Patent, Filed 7 Mar 85, patented 24 Nov 87,
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
A device for detecting small amounts of alkanes such as methane, ethane, propane, and butane gases, comprising an optical waveguide and a light source for propagating light therethrough apparatus for obtaining samples of air to be tested apparatus for adding water vapor to these air samples to yield gas mixtures with at least a 30 relative humidity and means for flowing these mixtures over the surface of the optical waveguide at a rate sufficient to favor condensation of the mixture on the waveguide surface to thereby form a thin film thereon. The presence of alkanes is determined by detecting the intensity of the light after propagation through the optical waveguide and then comparing that detected intensity to a reference. In a preferred embodiment, the optical waveguide is an optical glass capillary in which the surface is closed in a lens-like configuration at the detector end.
- Physical Chemistry
- Organic Chemistry