GB1407625A - Concentrator - Google Patents

Abstract

1407625 Helical concentrators HUMPHREYS ENG CO 23 Aug 1972 [8 Sept 1971] 39314/72 Heading B2H A method of concentrating and separately collecting from a mass of intermixed particles of different specific those particles having like specific gravity comprises mixing the particles with a liquid and causing the mixture to flow as a stream in a downward helical path; confining the stream in a manner to give the stream a cross-section, Fig. 6, which is relatively deep at its outer side and which diminishes in depth towards its inner side and has its deepest point positioned, as at 60, inwardly of its outer side; continuing the flow' until the particles therein stratify in accordance with their specific gravities and assume by reason of their speed and direction of travel a position such that particles of like specific gravities are inside by side zones extending longitudinally of the stream with those particles having the greater specific gravities in a zone at the inner side of the stream and with the specific gravities of the other zones decreasing towards the outer side of the stream; and thereafter separately removing and collecting from the stream the particles within each of the zones. The apparatus used to carry out the method is a helical concentrator of the type disclosed in specification 586777 but in which a wall portion 56, Fig. 4, is secured to the higher outer side 28 of the chute to project inwardly therefrom towards the lower inner side 26 of the chute so as to confine the outermost side of the stream as it flows down the chute to give it the desired cross-section. The wall portion 56 may be formed of hard rubber and may be permanently or removably secured to the chute. In a modification, Fig. 5 (not shown), the wall portion forms the top edge of the outer side of the chute. In a further modification, Fig. 7, one helical chute 62 is interposed between the convolutions of a second helical chute 64.