GB758775A - Improvements in apparatus for sorting solid products by density - Google Patents

Abstract

758,775. Separating solid materials. BERRY, F. J. B. June 18, 1954 [June 20, 1953; April 10, 1954], No. 18037/54. Class 117. An apparatus for sorting solid products comprises a container having a perforated base through which there is a pulsatory or intermittent flow of gas, and in which means of progression are provided to lead each layer of the stratified products towards one of a number of separate extremities of the container. In one embodiment, the container 10, Fig. 1, has a perforated base 14, the side walls 11 being provided with fins 26 and outlet sills 12, 13, at each end while a further outlet sill 40 is associated with a subsidiary chamber 39 forming part of the container 10. In the space below the base 14, a piston 16 is reciprocated by a crank 29 connecting rod 28 and rotating shaft 30. The space above the piston is divided by flexible partitions 27 into compartments 37 communicating by flap valves 18 with openings 17 in the piston through which air is drawn on the downward stroke to be discharged into the container 10 on the upward stroke. The shaft 30 also carries a crank 120 attached to a connecting rod 121 pivoted to a fixed support 125 so that the apparatus is reciprocated on pivoted supports 122, 123, 124, in synchronism with the piston. The mixture to be sorted is loaded into the container 10 at F and the lighter (black) fraction moves upwards and to the left over sill 12, the heavier (white) fraction moves over sill 13 and medium (shaded) material passes into the chamber 39 and up over the sill 40. In a second embodiment, compressed air from a fan 55, Fig. 2, in a hood 52 is admitted intermittently, through ports 43, into compartments 45 below the perforated base 14 by the reciprocating movement of slide-valves 46 operated by a rod 47, connecting rod 48 and crank 49 driven by a shaft 50 mounted on the apparatus. The shaft 50 also carries an out-of-balance weight 51, so that the whole apparatus is reciprocated on the flexible supports 33. To assist the required travel of the different components of the mixture to be sorted the air pulsations in the lefthand chamber 45 are arranged to be out of phase with those in the others by suitable positioning of the associated valve 46. In a modification of this embodiment further ports are arranged in the compartments 45 which communicate with the suction side of fan 55 and which are uncovered by further slide valves on the rod 47 when the ports 43 are closed, Fig. 3 (not shown). In further embodiments, the apparatus is not reciprocated arid the sorted material proceeds to the outlets down sloping surfaces. Thus the perforated base 73, Fig. 4, of container 70 slopes downwards towards a rising outlet chamber 78 provided with a sill 79 of adjustable height. A passageway 75 sloping in the other direction feeds the material into the container 70 and an inclined plate 76, of adjustable height, but lower than the passageway 75, leads away the lighter fraction. The heavier fraction finds it way into the chamber 78 and over the sill 79. The pulsating air supply is derived from a bellows 80, subdivided by partitions 82, drawing air from a conduit 111 provided with a damper 110 and driven, from the crankshaft 85, by connecting rods 84. The chamber 78 may be replaced by a rotating lock-type feed device, Fig. 5 (not shown), and the perforated base may slope in the other direction, Fig. 6 (not shown).