GB1469018A - Screening machine - Google Patents

Abstract

1469018 Screening apparatus BINDER & CO AG 24 Oct 1974 [24 Oct 1973] 46083/74 Heading B2H A screening machine comprises a screening box 6, a sifting screen 1, means 11 in the box for holding the edges of the screen in a fixed position and thereby supporting the screen for free movement in the box over substantially its entire area, a hopper 8 for feeding material to be sifted to the screen, a discharge 9 for discharging a fraction of the sifted material from the screen, a shaft 3 mounted in the box below and transversely of the screen, an oscillating means 5 for imparting oscillations to the shaft, and carrier arms 4 mounted on the shaft and supporting impact bars 2 below the screen for meshing intermittent contact with the screen, the bars 2 extending substantially parallel to the shaft and on each side thereof. A number of shafts 3 are provided parallel to each other and pairs of impact bars 2 are symmetrically mounted on each shaft by means of the carrier arms 4 which are arranged in the form of a V, pairs of bars on one shaft being staggered in relation to pairs of bars on an adjacent shaft. Vibrators 5, e.g. of the electromagnetic type, are arranged in contact with the shafts to impart a translatory (as shown) or rotary (Fig. 3, not shown) motion to the shaft. The shafts may be rotated in phase opposition or oscillated in phase so that a unitary translatory motion is imparted to the shafts to reciprocate all impact bars in each impact zone normal to the screen in unison. Alternatively, the shafts may be rotated in phase or oscillated in phase opposition so that a translatory motion is imparted to the shafts to reciprocate the impact bars normal to the screen whereby the reciprocatory impact of the bars mounted on adjacent shafts is out of phase so that a wave motion is imparted to the screen, this having a self-cleaning effect on the screen.