GB1469493A - Sifters - Google Patents

Abstract

1469493 Sifting apparatus NISSHIN SEIFUN KK 10 Feb 1975 5629/75 Heading B2H In a sifter comprising a number of screen boxes 2 disposed on top of each other, each screen box comprises a rectangular box frame 4', a screen 5 spread over the upper surface of the frame, and a plate 10 closing the bottom of the frame and arranged substantially horizontally, the sifter being arranged to be subjected to a circular motion so that, in operation, fine components 99 of articles 8 to be screened and fed onto the surface of the screen are caused to pass through the screen to be accumulated on the bottom plate 10 on which they are moved (dotted lines, Fig. 4) towards a discharging orifice 7 formed in one side of the frame 4', while coarse components of the articles which have not passed through the screen are moved over the screen surface in a direction (solid line, Fig. 4) at right angles to that of the movement of the fine components on the bottom plate, the bottom plate being provided on its surface with a number of ridges 11 which are arranged in the longitudinal direction substantially at right angles to the said direction of movement of the fine components, each of the ridges being formed by two upwardly inclined surfaces 11', 11" intersecting each other. The frame 4' is arranged within a frame 4 with equal gaps between the frames on three of their sides. The fine components discharging through orifice 7 fall into the gap formed between frames 4 and 4' at one side. The coarse components fall out from the screen surface through the gap formed between the frames at their sides adjoining those forming the discharge gap for the fine components. As shown in Fig. 4, the screen boxes 2 are arranged vertically such that the screen of a lower box is located directly beneath the gap for the coarse components -of an adjacent upper box whereby the coarse components can be subjected to multi-stage screening from top to bottom of the sifter. The surfaces 11' and 11" forming each ridge 11 of the bottom plate 10 are inclined to the horizontal at angles # 1 of 60‹ to 120‹ and # 2 of 5‹ to 60‹ respectively.