GB420768A - Improvements in apparatus for classifying or separating solid particles - Google Patents

Abstract

420,768. Gravity-separation apparatus. EWING, S. E. T., and WILLEY, J. L., Anmercosa House, Hollard Street, Johannesburg, South Africa. Oct. 23, 1933, No. 29340. Convention date, Nov. 3, 1932. [Class 46] [See also Group II] Apparatus for classifying or separating solid particles comprises a flexible sheet, rollers contacting with the sheet to produce a succession of transporting and agitating waves therein and means to subject the material in the trough of the waves to fluid in motion so as to remove particles of less density. Fig. 1 shows apparatus for separating sand from pulp. A rubber band 5 forms the sloping bottom of a tank 2 to which the pulp is fed by a conduit 3 and from which liquid and slime flow away over a lip 4. The band 5 is formed into waves by rollers 15 supported in brackets 16 carried by endless chains 17 passing round sprockets 18. The sand settling in the troughs is turned over as it is carried up the floor of the tank, so that slime is removed by the liquid. The sand is further washed by water from spray nozzles 33 and discharged through a shoot 19 and launder 7. The centre of the band is of such a length as to hang loosely in the troughs of the waves which rest on a decking 30, but the length of the edges corresponds to that of the side walls of the tank to which they are clamped by cleats 9. The rollers 15 are rotated by contact with track rollers 21, at such a rate relative to their translational movement that they have rolling contact only with the band 5. Figs. V and VI show a longitudinal and a cross-section of apparatus in which a flexible apron 35 is arranged to form a table. The apron is secured along its centre line to a bar 36 and supported loosely on either side by rollers 39 on chains 40 passing round sprockets 41. The rollers taper inwardly so that the troughs of the waves formed by the band are deeper towards their outer ends. The mixed material is delivered to the table by a feed box 50. Jets of fluid, which may be water when pulp is being treated or air when the material is dry, are delivered from nozzles 52, so as to cause the lighter particles to pass away from the ends of the wave troughs into launders 53, while the heavier particles are carried forward and collected in a launder 54. There may be a separate launder 55 for intermediate particles.