Patent GB-274587-A (GB)
Abstract: 274,587. Raw, G. April 30, 1926. Pneumatic separating; separating by shaking apparatus.-In a process and apparatus for separating coal or ores the materials are stratified according to density by the action of static pneumatic pressure in combination or not with means for producing a jigging action on the mass. The mass of materials is maintained at a depth which is uniform and in such relation to the pneumatic pressure, which may be continuous or pulsating. that the air or other gaseous fluid escaping through the mass has substantially no kinetic energy. In one form of apparatus, shown in Figs. 1 and 3, the separating table consists of a smooth pervious deck e forming the top of an airchest d which may be divided into compartments by transverse partitions k and supplied with air from a fan o, supply pipe n and branch pipes l comprising flexible sections m. The materials are fed and stratified on the rear part of the table which has parallel or diverging sides r. The sides of the forward or separating portion of the table converge, either uniformly or in steps, to the shoot 1 by which the densest material, such as stone, is discharged and which is hinged to the table at 2 and is adjustable in inclination. Between the discharge shoot and the forward end of the table a trap 41, Fig. 13, for the stone may be provided. This trap may be of narrower width than the end of the table, and may be hinged thereto at the lower end of an inclined portion 74. At various points along the length of the separating portion of the table skimmers 7, 13 may be placed to divert the materials of the different strata to discharge shoots at the sides. These skimmers are preferably adjustable in height and may consist of vertical plates with or without horizontal flanges 8 which may be perforated. The sides of the table are of substantial height to maintain the depth of material. In order to prevent piping of the material under the pneumatic pressure, the sides may overhang inwardly or outwardly or may be flared or the bottom corners of the skimmers may be cut away as shown at 83, Fig. 21. The table may be adjustable in inclination by hangers b with a screw adjusting device i, and is actuated by eccentric or other suitable mechanism. Fig. 9 shows a modification adapted for a pulsating pneumatic pressure. The air-chest 18 is connected by a converging passage 18a to a fan 21 through a pulsator casing 20 in which rotates one or more vanes 23 which periodically close the passage 22 into the air-chest. In order to produce sharply defined pulsations, curved or tapering insertions 20<a> 20b may be provided in the casing. Preferably the shaft of of the pulsator is geared to the shaft of the eccentric driving the table and synchronized therewith so that the forward feeding movement of the table coincides with the minimum air pressure. In this arrangement, the stone trap 41 is suspended by an adjustable hanger for varying its inclination. The air chest is stationary and connected to the table by a flexible air-tight cover 19, and is provided with a discharge opening 72 for any material that may percolate through the table. The upper part of the table is enclosed by a dustsettling chamber 66 connected to the table by flexible strips 70. The material is fed across the whole width of the table by a hopper t, Fig. 2, having an opening u which is adjustable by hing- ing the front wall w at x and providing it with a screw-adjusted sliding plate v. The hopper t is supplied from a large hopper y which is fed continuously by a conveyer device z. In the construction shown in Fig. 9, the hopper 54 is provided with a sliding and hinged front plate 55 and the main hopper 50 with a sliding door 49 adjusted by a rack and pinion device 52. The hopper 50 may be incorporated with the dust casing 66. In all the constructions described, the skimmers and hopper may be mounted on stationary supports.