GB715176A - New or improved apparatus for treating and particularly for separating loose material such as gravel and the like - Google Patents

Abstract

715,176. Pneumatic separating. MIAG MUEHLENBAU UND INDUSTRIE GES..July 16, 1952 [July 17. 1951; June 20. 1952; June 20, 1952; June 20, 1952], No. 17937/52. Class 117 A winnowing apparatus comprises a vertical duct through which the air stream rises s and an annular material entry therein, the width of which is adjusted automatically. In one embodiment, air is drawn upward through the duct 1 from a manually adjustable air intake 28 .. 31. The annular material entry is formed by the gap 33 between the lower rim of a hollow member 4, into which the material is fed through a lateral inclined duct 7, and the conical top 18 of a lower hollow member 5. The latter is kept in rotation by an internal motor 20, and is pressed upward by a lever 24 and counterweight 6. The weight of material. falling on to the conical surface 18 automatically adjusts the annular gap 33 according to requirements. The material is separated into three portions, the first heavy fraction falling into the hopper 3. A second fraction falls into an upper hopper 11 when the air velocity falls in the wider region 32 of the tunnel 1, the mouth of the hopper being covered by a perforated hood 25 of triangular semi-elliptic, parabolic &c. cross-section. The exit pipe 8 of hopper 11 is covered by a flap valve 9. The third and lightest fraction is carried by the air stream through the outlet pipe 2. In another embodiment the member 5 is not rotated and the hood 25 is replaced by a series of stepped coaxial cylindrical baffles, Fig. 2 (not shown). In the simplest embodiment the member 5 is urged upwards by a spring and no provision is made for deriving an intermediate fraction from the material, Fig. 1 (not shown).