Patent ID: 6100488
Filing Date: 2000-08-08
Classification: B07C,Y10S

Abstract:
A granular material color sorting apparatus comprising a transfer device causing material grains to fall down in a substantially fixed locus; at least one optical detector unit mounted along the falling-down locus of the material grains, the optical detector unit including a colored grain detection sensor section for optically detecting colored grains different in color from good material grains and a foreign matter detection sensor section for optically detecting foreign matters in similar color to the good material grains or transparent; an injection nozzle device for injecting air to the material grains after optical detection to remove them; and a control unit for controlling operation of the injection nozzle device in response to the detection by the optical detector unit, the control unit having a comparator section for discriminating good material grains and bad grains of colored grains and foreign matters in response to output signals from the optical detector unit, an injection time control section for activating the injection nozzle device over a predetermined period of time in response to discrimination by the comparator section, and an injection delay control section for delaying activation of the injection nozzle device for a predetermined period of time after the detection by the optical detector unit, the injection time control section and the injection delay control section storing two sorts of injection times and injection delay times different in criterion for colored grains and for foreign matters, determining an injection time and an injection delay time depending on which of a colored grain and a foreign matter is detected and in accordance with the magnitude of a detection signal, and outputting the determined times to the inject nozzle device.