Measuring arrangement for the determination of light-absorbing part, respectively, in particular a mist and smoke, in the atmosphaere

摘要

1,213,262. Measurement of atmospheric light absorption. WINSLOW TELETRONICS Inc. March 3, 1969, No. 11172/69. Heading G1A. In an arrangement for indicating the percentage of light absorption by the atmosphere a collimated beam from a light source is split between a local and a remote detector which are connected to provide opposing voltages and in series with an adjustable voltage which is provided to counterbalance the former, the amplified output being applied to a recording meter. The source may be a helium gas laser emitting light energy having a wavelength within the region of 0À6-0À7 microns, and the detectors may be protected from the ambient light by monopass filters. The detectors may be photoemissive or photo-conductive, and a motor driven cam switch may be provided to disconnect briefly the distant detector at least once a day for test purposes. Calibration procedure for balancing the two detector outputs and the first detector output against the adjustable voltage is described. The apparatus including both detectors may be mounted on an aeroplane or a truck.