GB671941A - Process and apparatus for separating finely divided substances - Google Patents

Abstract

671,941. Separating granular materials; grinding and crushing. DULAIT, J. April 6. 1949 [April 6, 1948; March 26, 1949], Nos. 9399/49 and 9400/49. Classes 59 and 117 In an arrangement for separating granular materials such as ores, grain, and the like into fractions according to particle size, the material is projected from a rotor 2 through a narrow slit 5 to form a thin annular web which is caused to impinge against an annular deflecting surface 7 before any spreading of the web thickness so that a gaseous current can divert the fine particles from the path of the coarse particles without interfering with the latter. As shown in Fig. 1, the rotor comprises a disc 2 mounted on a horizontal shaft 1 and having radial blades 3 supporting an annular conical plate 4 which defines with the disc 2 a narrow peripheral slit 5. The rotor rotates in an enclosed stator comprising a member 6, 8 bounding the plate 4 and slit 5 of the rotor and connected to a conical deflecting member 7, the end 9 of which is connected to a cyclone separator 10. Material fed to the rotor 2 is projected with accompanying air through the slit 5 and the annular gap bounded by the part 8 of the stator to impinge on the conical stator wall 7, the coarse particles falling back to be discharged through an outlet 12 in the stator 7 and the fine particles being carried in the air stream to the cyclone 10. The air stream may be assisted by a fan 13 on the shaft 1 within'the stator 7, and additional air inlets 14 may be provided in the outlet conduit 12. In alternative arrangements described the material may be directed axially from the slit 5 to a conical or concave deflecting wall and the additional air inlets may be arranged peripherally in the walls of the stator 7 and conduit 12. The main air intake may be via a ring arranged closely behind the projected web of material, and the axis of the stator 7 may be directed upwardly with an additional discharge conduit being provided near its apex for any less fine particles settling out. Fig. 7 shows a crusher having a rotor 25 with front and rear blades 26, 27 rotating in a stator with front and rear peripheral chambers 28, 29, the rear rotor blades 27 having a cover disc 2 defining, with a ring 30 closing the rear stator chambers 29, a narrow slit 5 through which crushed material is projected against a conical stator extension to effect a separation as described above. In like manner the separator 2, 7 may be combined with a hammer mill.