GB626862A - A method of and apparatus for grading and/or separating materials of different densities, such as coal, ore and the like - Google Patents

Abstract

626,862. Washing granular materials. HARVENGT, E. June 25, 1946, No. 18971. Convention date, June 25, 1945. [Class 82(ii)] In a method of and apparatus for grading and/or separating coal ores &c. the material is fed from a shoot 2 on to a screen or grid 4 to which is given a reciprocating motion comprising vertical and horizontal components or substantially horizontal components only, where it is subjected to liquid impulses synchronized with the motion of the screen, the impulses being preferably produced by a movable member such as a piston 9 and being associated, if desired, with liquid currents of constant or variable intensity introduced at 30. The discharge of the graded products, or of certain categories thereof, may also be controlled in synchronism with the motion of the screen or with the liquid impulses by means of the plates 16, 17 articulated at 18, 20 whose movements are dependent on those of the screen 4. In the arrangement shown in Fig. 1 the motions of the screen 4, which is pivoted at 5 to links 6 turning about axes 7, are communicated from a rotary cam 10 which also controls the oscillations of the piston 9, by a linkage 11, 14 preferably so arranged that on the downward motion of the piston the screen moves downwardly and backwardly (i.e. towards the trough 2), an abutment 3 preventing rearward movement of the materials on the screen. Light products pass over the plate 17 to the trough 32, and heavies through the discharge space between the screen and the plate 16. By means of a linkage 26, 27 controlled by the screen or piston motion, the plates 16, 17 are given a preferably vertical motion such that the articulation 18 is uppermost, (as shown in broken lines), when the screen is lowermost, thus making the discharge opening for heavies a maximum and reducing any tendency for the heavies to pass over into the light prcducts outlet 32, and vice versa. Mechanism 22a, 22b is provided for making an initial adjustment in the position of the articulation 22 according to the discharge required. There also may be provided a succession of two or more screens 4 with interposed devices discharging into the bin 1 itself or with separate receptacles. The method and apparatus are said to be particularly suitable when used in conjunction with inclined washing troughs, in which case upward currents supplied by the inlet 30 are said to be desirable. One arrangement of such apparatus is shown in Fig. 2, the inlet and outlet troughs 2, 32 of the jigs 1 being connected to inclined troughs such as 35, 37, and the heavy discharges being removed from the jigs via pocketed rotating drums 36.