Patent GB-218354-A (GB)
Title: Improvements in electrostatic separation of particles
IPC: B03C7/00
Filed: 1923-03-03
Abstract: 218,354. South Metropolitan Gas Co., Woodhall, Duckham, & Jones (1920), Ltd., and Hatfield, H. S. March 3, 1923. Electrostatic separators.-In a process for separating substances in a finely - divided condition, such as the constituent minerals of a finely-ground ore, or coal from shale, the material is brought into contact with suitable insulating materials placed in a space between two electrodes connected to a source of high - frequency alternating current such as is used for continuous wave wireless transmission. In one form, Fig. 1, wires a are mounted as shown in plates b, b<1> mounted on insulating supports d and connected to the poles of a, high-frequency generator e. The wires a are covered with glass c, which may be fused on them or which may be slipped over them. The mixture of minerals is fed in at the top of the apparatus and falls among the wires, where the separation takes place, some materials clinging to the tubes c and others falling, through without being affected. In a second form, Fig. 4, the materials are fed on to inclined metal plates i connected to a source of high-frequency current and carried by a framework h of insulating material. An inclined revolving shaft f carries a number of parallel slate discs g which revolve partly inside the framework h. The materials pass down the plate i and fall through slots k on to the discs g. The unresponsive material slides off or is projected off the discs g and the responsive material adheres to the discs g and is carried outside the field created by the plate i where it drops off. In a third form, the material is fed from a hopper on to a rotating roller covered with insulating material, a curved insulated metal saddle being fixed concentrically with, and over part of, the roller, the materials being fed into the space between the roller and the saddle. In a fourth form, the insulating surfaces are formed like a Venetian blind, alternate surfaces being connected to poles of the generator and the minerals being fed thereto so as to fall on the slots. In another form, Fig. 7, a frame s, carrying slots p alternately connected to the poles of the generator, is mounted on a rod t carried by a bracket t<1> mounted, or made of such material, so that it can vibrate in a vertical plane, preferably by a pulley t<3> fixed on a spindle t<2> turning in bearings on the bracket and carrying an eccentric weight. The hopper u is mounted so that it can be vibrated by a cam u<2> carried on a post u<1> mounted on the bracket t' and is provided with openings covered by wire mesh u<3>. The unattracted material falls into hoppers v having apertures in the bottom through which the material falls into alternate hoppers w and slides into a conveyer trough x. The current is then cut off, the cam being turned so that it does not contact with the hopper and so cuts off the supply to the slots p, and the troughs v moved so that they are in communication with the troughs w which did not receive the un.. attracted material, the attracted material sliding down these troughs into a conveyer trough y. A single-power shaft carrying cams may operate the cam u<2>, move the troughs v, and control the current supply to the slots p.