Oil detection device for e.g. marine bilge monitoring - has illuminated soil cell with outputs fed to photo detectors so that oil concentration can be computer from difference between signals

摘要

The scatter cell of the detector arrangement comprises a housing through which water carrying suspended oil may flow, and is provided with an inlet window for incident light and outlet windows (13,14) for receiving light scattered from the suspended oil. Typically the incident light beam is provided via an infra-red solid state laser but another light souce may also be used. A baffle may be mounted adjacent the window to ensure that only scattered light reaches the outlet windows. Scattered light reaching the windows is fed to respective photodetectors, pref. via optical fibres. Advantageously the scatter cell also includes a further output window whereby the intensity of the incident beam may be monitored thus providing for computation for compensation of changes in that intensity. The outputs of the photodetectors are coupled to electronic circuitry, e,g, a microprocessor, programmed to compute an oil concentration level from the absolute and relative values of the photodetector outputs.