Patent GB-530787-A (GB)
Title: Improvements in apparatus for gravity separation of granular material
IPC: B03B11/00
Filed: 1939-06-01
Abstract: 530,787. Wet separating. HIRST, A. A., and SIMON-CARVES, Ltd. June 1, 1939, No. 16101. [Class 82 (ii)] In apparatus for wet separation of granular material of the type in which the material is fed into a separating vessel containing a separating fluid consisting of a suspension of finely divided material in water whose density is intermediate that of the materials to be separated, a relatively shallow vessel is provided with inlet and outlet compartments separated by a partition under which the fluid, or part of it, flows, the flow being adapted to sweep through the vessel, particles of the same density as the flow, means being provided for regulating the velocity and/or depth of the underflow and also mechanical scraping mechanism for removing material sinking in the trough. The material to be treated is fed by a shoot 30 along a channel 31 and down a shoot 32 into liquid contained in a tank 10 provided with inclined ends 11, 12 and through which pass an endless scraper 14 mounted in members 18, one of which is driven by a chain 19. The blades 15, Fig. 4, of the scraper are substantially U- shaped, pivoted on link pin 16 and have outturned ends 17. A partition 20 formed of two overlapping plates adjustably secured together is mounted in the trough. The material floating in the liquid is removed by a conveyer 33 which directs it into a channel 21 provided with a baffle 22 having an adjustable lower portion 23, and is received on a perforated screen or jigger 36, Fig. 2, mounted in the channel 21. The material in the portion of the screen over the channel 21 is drained of suspension and that on the rest of the screen is washed by sprayers 37, the solid material being discharged down a shoot 39 and the liquid passes into a cone 38. The material removed by the scraper 14 passes through an opening in the end 12 partly covered by an adjustable plate 24 on to a perforated screen or jigger 25, Fig. 3, the material on one part of the screen being drained of suspension which passes into a cone 26 and that on the other part being washed by sprayers 27, the solid material passing away by a shoot 29 and the liquid passing into a cone 28. To maintain the density of the suspension in the trough 10 constant, the suspension removed by the pipes 43, passes to a reserve tank 40 and is pumped back into the trough 10 through a pipe 41 by a pump 42, the liquid in the tank being mixed by circulating the suspension by a pipe 44 and pump 45. The liquid from the cones, 28, 38, Figs. 2 and 3, is conveyed by pipes 46-to a dilute suspension tank 47 provided with a fine screen or jigger 47, the slurry on which is washed by sprayers 49. The underflow from this tank is pumped by a pump 51 through a pipe 52 to a settling-tank 53, having an overflow rim from which clear suspension is passed by a pipe 55 through a density control device 62 and a pipe 60 to the tank 40. The base of the tank 53 is also connected through a valve 61 to the device 62. An overflow pipe 56 from the tank 53 also leads to a tank 57 from which the sprayers 27, 37 and 48 are fed. One or more further partitions 63 may be provided in the trough 12, each provided with a weir over which the floating material passes to be treated in an apparatus similar to that shown in Fig. 3.