GB836424A - Improvements relating to the separation of free liquid from masses of loose solid material - Google Patents

Abstract

836,424. Filters ; gravity-separation apparatus. STAMICARBON N.V. July 23, 1956, No. 22746/56. Class 46. [Also in Group XIII] From a feed trough 5, Fig. 1, kept charged with the material to be treated, material flows continuously onto a stationary table 1, preferably imperforate but optionally wholly or partly perforate, over which move two series of scrapers 2, 2<SP>1</SP>, Fig. 2, mounted respectively on endless chains 3, 3<SP>1</SP>. The material is thus urged towards a slot 6, and during its progress liquid gravitates from the upper layers C to the lower layers B of the mass. On reaching the slot 6 the lower layers B pass into it, the upper layers C passing on over the far edge 6a of the slot 6. A plate 7 having a downwardly-stepped portion 9 underlaying the slot is adjusted longitudinally so that the inclination to the horizontal of an imaginary line 14 joining the end of the portion 9 to the slot edge 6a is always greater than the angle of repose of the lower layers B (the latter angle being a function of the water content of the layers). Material discharging through the slot is returned to feed by a pump 13. In Fig. 3 an endless belt 17 is moved in the direction of the arrows, the bed being divided at the edge 19a of a plate 19 parallel with the bed and preferably adjustable vertically. In Fig. 4 a flat perforate screen 21 is connected to the delivery end of the wet screening apparatus 22 of any of the Specifications 791, 520, 791,857, 791,858 and 791,859, on to which material to be treated, e.g. water and fine coal, is tangentially fed at 23. Most of the water together with part of the fine product is collected in a tank 24, the residue passing on to the screen 21 where it slides down until checked by a plate 27a rotatable about a shaft 26 parallel to the screen 21 but spaced from it by a gap 28. Water sinks through the bed, some of it dripping through the screen perforations into a shoot 29 and tank 30. The plate 27a is adjusted so that its free edge 36 is sufficiently below the sloped surface 37 of the bed A to allow discharge, over that edge, only of material having a moisture content below the required predetermined value. Wet material in the lower part B of the bed passes through slot 28 and slides over a plate 27b, pivoted on shaft 26, into the tank 30. The setting of plate 27b (independent of 27a) determines the minimum water content of material passing over it. In a modification the water passing through screen 21 is discharged separately at 35 above a wall 34.