Bulk sorting of particulate material

Apparatus for bulk sorting particulate material into fractions according to the degree to which that material possesses a certain characteristic comprising

• means to move said particulate material in a continuous stream along a path, said means including a generally horizontal belt conveyor mounted on movable support means so as to be vertically movable and material feed means which comprises a hopper to receive material to be sorted and which, in operation of the apparatus, feeds material from the hopper onto the belt conveyor at a rate which varies according to the vertical position of the conveyor belt, the vertical position of the conveyor belt being dependent on the weight of feed material in said hopper;
• a detector positioned such that material moving in said stream along said path will pass it and responsive to said characteristic so as to produce a time sequence of detector signals dependent on the degree to which material passing the detector possesses said characteristic;
• control means to receive said detector signals and to derive therefrom control signals indicative of contiguous zones of the bulk material in the stream possessing said characteristic to differing degrees;
• and
• stream divider means operative in response to said control signals to divide the stream of bulk material into separated material fractions such that material of differing zones is separated into different fractions.