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Opacity meter for monitoring exhaust emissions from non-stationary sources

United States Patent

6,025,920
February 15, 2000
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
Method and apparatus for determining the opacity of exhaust plumes from moving emissions sources. In operation, a light source is activated at a time prior to the arrival of a diesel locomotive at a measurement point, by means of a track trigger switch or the Automatic Equipment Identification system, such that the opacity measurement is synchronized with the passage of an exhaust plume past the measurement point. A beam of light from the light source passes through the exhaust plume of the locomotive and is detected by a suitable detector, preferably a high-rate photodiode. The light beam is well-collimated and is preferably monochromatic, permitting the use of a narrowband pass filter to discriminate against background light. In order to span a double railroad track and provide a beam which is substantially stronger than background, the light source, preferably a diode laser, must provide a locally intense beam. A high intensity light source is also desirable in order to increase accuracy at the high sampling rates required. Also included is a computer control system useful for data acquisition, manipulation, storage and transmission of opacity data and the identification of the associated diesel engine to a central data collection center.
Dec; John Edward (Livermore, CA)
Sandia Corporation (Livermore, CA)
08/ 642,974
May 6, 1996
STATEMENT OF GOVERNMENT INTEREST This invention was made with Government support under contract no. DE-AC04-94AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights in the invention.