GB1352886A - Screening machine - Google Patents

Abstract

1352886 Screening machines BUEHLER AG Gebp 16 June 1971 [17 June 1970] 28198/71 Heading B2H A screening machine comprises a housing 1, Fig. 1, in which is mounted a tubular screen 7 with its ends secured to the housing at 9, 10 and a rotor 3 having vanes 5, Fig. 3, arranged within the screen and connected to drive elements 33, 35-37, the screen being connected, between the regions where it is secured to the housing, with a positive oscillatory drive 21-23 movable relative to -the housing. The rotor shaft 2 is driven by an electric motor 37 through pulleys 33, 36 and a belt 35 which also drives a shaft 21 at a higher speed through a smaller diameter pulley. The shaft 21 is provided with eccentrics 22 on which are mounted connecting rods 23 at their end 24, the ends 26 of the connecting rods being connected to a tubular rod 27, Fig. 5, secured to the housing 1 by hollow rubber springs 28. Alternatively, the ends 26 of the connecting rods are connected to an eccentric shaft parallel to and rotating synchronously with the shaft 21. Counterweights are removably and adjustably secured on the shaft 21. Each connecting rod has a rigid entrainment surface 29 in contact with half the periphery of the screen, the other half being surrounded by a stirrup 30 fastened to the connecting rod 23. Supporting rings 31 are arranged internally of the screen at the entrainment regions. The housing 1 is supported by rubber blocks 18 on a frame 19 which may be insulated from the ground by further rubber blocks. In operation, product to be sifted, e.g. flour, is fed through an inlet 12 into the screen 7 where it is thrown outwardly by the vanes 5 and is conveyed by the vanes along the screen. The vanes also effect cleaning of the screen. The finer particles pass through the screen into hoppers 15, 16 and coarser particles are discharged into a hopper 13. The eccentric shaft 21 may be constructed as a crankshaft. The screen 7 may be made of nylon or wire gauze. In a modification, Fig. 7 (not shown), the eccentric shaft (21) is mounted in a bearing housing (43) on top of the housing 1 and has an eccentric (22) which, through a connecting rod (45) extending through a passage (47) in the housing 1, drives the connecting rods (23) which are connected fast to one another by a tube (46) and which are arranged vertically. The discharge end of the housing is closed by a cover (52) in which the discharge hopper 13 is formed and which is connected as a unit with both ends of the screen so that the screen can be removed from the machine without dismantling the drive.