Patent GB-1393213-A (GB)
Title: Device for sorting grain
IPC: B07B13/11
Filed: 1973-03-15
Abstract: 1393213 Grain sorting apparatus T SATAKE 15 March 1973 12660/73 Heading B2H An apparatus for sorting a mixture of different grains, e.g. hulled and unhulled rice, according to specific gravity comprises a plate 1, Figs. 5 and 6, for receiving the mixture of grains to be sorted, the plate having a roughened surface for exerting a frictional force upon grains thereon, being inclined longitudinally at an angle γ to the horizontal and oscillatable in a direction as shown by the arrows W' transverse to the direction of inclination and at an acute angle to the vertical; means, e.g. a feed hopper 2, for supplying the mixture of grains to be sorted to the upper part of the plate; and a plurality of discharge openings 8, 9, 10 for sorted grains at the lower part of the plate, whereby in operation the mixture of grains flows down the inclined plate and is sorted by the transverse oscillating movements of the plate and the grains are discharged according to their specific gravity through the openings 8, 9, 10, the plate being provided with a side wall G at that edge thereof which constitutes the leading edge during an upstroke of the plate. The roughened surface of the plate 1 may have a mesh or, as shown, a saw-tooth configuration. The plate is surrounded on three sides by walls to form a pan which is secured to a base 3 mounted on pivotable links 4 and oscillated by means of an eccentric 5. Laterally the pan may be horizontal, Fig. 5, or inclined at an angle α, Fig. 10, which may be adjusted by means of a turnbuckle (11), Fig. 11 (not shown). When sorting rice, the hulled rice of higher specific gravity is discharged through opening 8, the unhulled rice of lower specific gravity through opening 9 and a mixture of both through opening 10. In a modification, Fig. 12, a change-over valve 13 is provided in the discharge opening 8 and is operable by a solenoid 14 through a timer T associated with a limit switch 18 mounted in the hopper 2. Thus, for short time after the start of the sorting operation, as both the hulled and unhulled rice tend to be discharged through the opening 8 due to the small quantity of rice on the pan, the valve 13 is in the full-line position allowing the rice to be fed back several times to the hopper 2 via a trough 15, a lift 16 associated with a supply source 19 and a trough 17, until the pan is entirely covered by the rice. At this time, the rice in the hopper reaches a height H and energizes the limit-switch 18 which transmits a signal to the timer T for operating solenoid 14 to change the valve over to the dotted-line position.  In a further modification, Figs. 13 and 14 (not shown), the turnbuckle (11) for adjusting the angle α of lateral inclination is automatically adjusted by a reversible motor (26) operable by microswitches (24, 25) actuable by a pivotable balance rod (22) carrying detecting plates (20, 21) located under the discharge openings 8 and 9. The plates (20, 21) will detect the quantity of rice discharged through the respective openings according to the property of the hulled and unhulled rice and cause the angle α to be adjusted so that only hulled rice is discharged through opening 8. In a further modification, Fig. 16, the plate 1 of the pan is provided with holes 29 for the passage of air which is sucked or blown through the holes to cause fluidisation of the rice thereby assisting separation and removal of the dust produced during the sorting operation. A cover 31 made of rubber or air-proof cloth is placed over the plate 1 and is connected to a pipe 30 for the flow of air. The feed hopper 2 is connected to a supply port 33 by means of a bellows-type conduit 32.