Patent GB-421553-A (GB)
Title: Improvements in or relating to mineral separation and the like
IPC: B03B4/00
Filed: 1933-06-22
Abstract: 421,553. Separating solid materials. BERRISFORD, W. H., Highfields, Sandon Road, Longton, Stoke-on-Trent. June 22, 1933, No. 17827. [Class 117] In the separation of coal and dirt and other mixtures of materials of different density, the materials are fed on to an inclined table 1 to which a reciprocating motion is imparted tending to convey the materials upwards, a sudden drop of the table is imposed on this movement at some part of the cycle, preferably towards the end of the upward movement, and the inclination of the table is such that one constituent is carried to discharge at the upper end while the other constituent passes downwards to discharge at the lower end. Preferably, the action is assisted by a current of air passing up through the table and the bed of material, and the charge may be divided by screening into two or more parts which are separately treated on different parts of the table. The apparatus described comprises the table 1, the separating surface of which is preferably provided with ratchet conveying projections, as by being formed of expanded or perforated sheet with projections on the lower sides of the openings, or of wedge wire, the upper surface of which is set at a steeper angle than the general slope of the table. In the preferred construction the table runs on ratchet rollers 3, held in one direction by a pawl 4, as described in Specification 396,807 and is driven by suitable mechanism such as the crank and connecting rod 10 or by any form of quick-return motion. The base 5 of the machine is pivotally mounted at 6 and is adjustably supported at the upper end 7 to enable the inclination of the table to be varied. Where an upward air-current is used, this is supplied by a conduit 18, subdivided by baffles 19 to equalize the flow and connected to the table by flexible extensions 20. A baffle 21 consisting of a perforated plate is placed over the end of the conduit so as to produce a pulsation when the table drops. The material is fed in a direction towards the upper end of the table by means of two baffles 12, 12<a> carried by the sides 11 of the table and coacting with a fixed hopper 13. The upper end 14 of the table is constricted as by providing hinged parts of the sides 11 or an adjustable baffle so as to form a bank for the constituents conveyed in that direction, and a weir may be provided at the lower end 16 of the table to maintain the depth of material under treatment. A hood 22 encloses the upper side of the table and is connected by a conduit 23 to any usual form of dust collector. A middlings product may be evacuated from near the upper end of the table by apertures formed in the sides as described in Specification 326,961, [Class 117]. Modifications are described in which the table is provided with two or more separating areas and the charge is divided among these by screens incorporated in the machine. The clean and refuse products from these different areas are each preferably guided to a common outlet, and a middlings product from each area may be returned to the head of the machine for retreatment. In a further modification, a dustremoving device as described in Specification 413,294 may be incorporated in the machine to de-dust the material on its way to the table or screening devices.