GB1130152A - Sorting apparatus - Google Patents

Abstract

1,130,152. Photo-electric colour sorting of objects. ELCEMCO Inc. Sept.28, 1965 [Sept.28, 1964], No. 41257/65. Heading G1A. In an arrangement for sorting a succession of moving objects e.g. coffee beans 16, Fig. 1 passing down a transparent tube 12 according to the intensity of light reflected by them as they pass through a point in their path on which light is focussed from a ring of sources 58 on a plane transverse to the direction of motion, the reflected light is detected by one or two annular sensors 46 situated above and/or below the focussing point and centred on the axis of the tube to produce a signal for controlling a sorting deflector 26 in accordance with the combined detector outputs or of the ratio of the outputs. The acceptable range may be a middle range with signals outside the range permitting operation of the deflector and the selection parameters may be adjustable. The lamps may have lenses in their envelopes. Light filters for example red and green may be positioned over the respective sensitive surfaces of the cells in an arrangement where the ratio of the signals effects control. A photo-electric object presence detector 20, 22 is positioned at the bottom of the tube, and produces a pulse for operating the deflector in response to each object and the pulses are suppressed or permitted to pass by a gate circuit (86) Fig. 4 to which pulses derived from the annular detectors are also applied. The amplifier signals from detectors (46) are applied to voltage level detector circuits (74), (76) responsive to respective first and second pulse levels. These circuits which are monostable transistor circuits and are switched when input plus adjustable bias exceeds a predetermined value, apply pulses to a disabling circuit (78) which also includes a monostable multivibrator (118), (120). An input pulse from circuit (74) switches the pair and a unijunction transistor (126) is fired by the build up across a capacitor (130). A disabling signal established across a resistor (142) is applied to the gate circuit and the voltage across a resistor (140) switches the pair (118), (120) back to normal. A pulse from circuit (76), indicating a higher level signal from the photo-cells, switches the pair (118), (120) back to normal before a disabling signal can be established. A deflector operating coil (170) is connected in the emitter circuit of a power transistor (168) and may control a rocking deflector, a bent spring, or an air jet, to deflect wanted or unwanted objects, as desired, accoding to which predominate. A circular aluminium conveyer wheel for supplying objects individually in succession to the mouth of the tube has cut away tubular scoops mounted around its periphery, and is rotated through the beans to lift them to the tube mouth where they are injected by compressed air. The scoops may be constructed by force fitting short lengths of tubing into holes in the wheel and the blast of air injecting the object may be used to remove dust or beans of small size. Objects may be thrown into the tube from the wheel by centrifugal force.