Patent GB-1359718-A (GB)
Title: Apparatus for the sorting and separation of granular material
IPC: B03B4/00
Filed: 1971-07-27
Abstract: 1359718 Separating material by pneumatic and vibrating means BUEHLER AG Gebr 27 July 1971 [3 Aug 1970 5 July 1971] 35372/71 Heading B2H In an apparatus for sorting and separating granular material by feeding the latter on to an inclined air-pervious, oscillatable support, upward air flow through the support and oscillatory movement of the support cause a concentration of a major heavier fraction of the material to form a lower layer upon the support and a concentration of a minor lighter fraction to form an upper layer above the support, and the heavier fraction is conveyed by the oscillatory movement along a path in a substantially horizontal region from a material arrival point upon the support towards a discharge outlet, and the lighter fraction flows away in a suspended state along a region encompassed by the line of fall through the arrival point and by a line through the arrival point having half the inclination of the said line of fall.  In Figs. 3 to 5, the apparatus comprises a housing 1 bounding an air-pervious material support 4 comprising a wire mesh screen 5 beneath which is spacedly mounted a perforated plate 6. The upper, hood-like part 2 of the housing has a pipe 7 connected by a flexible bellows 8 and a conduit 9 to the suction side of a fan 10. Alternatively, compressed air may be supplied from below the support 4. The hopper-like lower part 3 of the housing is subdivided by walls 11, 12, 13, extending to the support 4, into air-supply chambers 14-18. The chambers 14-17 have air inlet apertures 19 controlled by a rotatable disc 22 provided with through flow apertures 23. The chamber 18 is connected by an aperture 20 in the wall of housing part 2 directly to the inlet air. The housing is mounted for oscillation in a direction parallel to the side 25 of the support 4. For this purpose two straps 26, 27 are secured to one end of the housing and to a tube 28 which carries bearings 29, 30 supported by springs 31 on supports 32, 33 set on a rocker 34. A block 35 is secured to the opposite end of the housing and is supported by springs 36 on a support 37 secured to the rocker 34. The rocker 34 is pivotable about a pin 38 on a second rocker 39 which in turn is pivotable about a pin 40 in supports 41 on a stationery bedplate 42. The inclination of the rocker 39 can be modified by a screwthreaded pin 43 provided with a handwheel 44. The inclination of rocker 34 can be altered by a lifter 46 having a control handwheel 53. Hence rotation of handwheels 53, 44 alters the longitudinal and transverse inclination of rocker 34 and therefore of the support 4. Vibration is imparted to the housing 1 by a motor 56 which is mounted by straps 57 on a block 55 secured to the tube 28 and having eccentric weights 58 inclined at an acute angle to the support 4. The motor 56 also oscillates the disc 22 via a ratchet coupling 59 and V-belt and pulleys 62, 63, 64. Along the side 25 of the support 4 are arranged funnel shaped outlets 65, 66, 67 for the heavier, mixed and lighter fractions of the material respectively. In a modification, the outlets 65 and 67 adjoin, the outlet 66 being omitted. An overflow edge 68 extends along the outlet 66 and directs the lower heavier fraction towards the outlet 65 while the mixed fraction passes over the edge into the outlet 66 and is conveyed back into the inlet region 70, 71 for further separation. Adjustable flaps 97, 98 control the size of the inlet regions to the hoppers leading to the outlets 65-67. The material is fed down a feed device 70 on to a feed channel 69 having a plurality of closable outlet apertures in its bottom by which the arrival point 71 of the material on to the support 4 can be varied. In operaion, the fan 10 draws air by way of the apertures 19 through which the air flow is periodicaly varied, by means of the rotating disc 22 driven by the vibratory drive, to cause pulsating air flow through the support 4. A stronger pulsating flow occurs in the region of the chamber 15, due to its smaller cross-section, than in the regions of the chambers 14, 16 and 17. Through the part of the support 4 associated with the chamber 18 a strong continuous air flow is produced via the aperture 20. Instead of comprising wire mesh screen 5, the support 4 may be in the form of a rough-hole perforated plate provided with holes pierced so that the roughness is on the face of the plate intended to support the material. Reference has been directed by the comptroller to Specification 1247963.