Optical sorting apparatus

Self-synchronized optical sorting apparatus for sorting objects in response to light reflected from said objects including,

• a pair of light detecting means with different response characteristics producing a pair of light related signals,
• a pair of integrating means for providing integrated signals in response to light related signals produced by said light detectors, and circuit means for producing an output if, and only if, the difference between said pair of integrated signals exceeds a first predetermined value,
• a pair of comparator means, each provided with an identical input signal selected from one of said pair of light related signals,
• one of said comparator means producing a signal if, and only if, said input signal is below a second predetermined value,
• said other comparator means producing a signal if, and only if, said input signal exceeds a third predetermined value,
• synchronizing means connected to both said integrating means and said one comparator means for producing a pair of synchronizing signals to enable said pair of integrating means and said one comparator means,
• said synchronizing means receiving, as an input signal, a signal selected from one of said pair of light related signals,
• and reject means for deflecting said objects in response to an output signal from said pair of integrating means or said one or other comparator means.

Optical sorting apparatus including a stationary analysis head for providing reflected light from a falling object to a light responsive transducer over an unimpeded path including a plurality of light sources, spaced about said head, for illuminating said falling object,

• said head comprising:
• a pair of parallel annular rings spaced apart to thereby define a gap therebetween with a central axis of each ring substantially co-linear with the path of said falling object,
• a plurality of optical fibers each having one end located in said gap between said rings and each spaced circumferentially one from another about said axis, each of said ends receiving reflected light unimpeded by any object,
• each of said ends spaced radially outward from the inner edge of said ring, and
• low pressure air means for slightly increasing air pressure adjacent said ends to prevent dust and/or other debris from masking said ends, said low pressure air means having a discharge opening adjacent said fiber ends and located in said gap.