GB1237999A - - Google Patents

Abstract

1,237,999. Screening and air-sifting apparatus. MIAG MUHLENBAU UND INDUSTRIE G.m.b.H. 14 May, 1970 [4 June, 1969], No. 23505/70. Heading B2H. An apparatus for cleaning granular material comprises an oscillatory screen 11 which slopes in opposite directions downwards from a feed zone for the material to be cleaned towards two stationary up-draught classifiers 17 arranged one on each of two opposite sides of the screen, the screen being mounted so as to be capable of performing circular vertical vibrations and to deliver material which has not passed through the screen to the classifiers 17. The screen 11 may be uniformly convexly arched or, as shown, is supported by strip sections 13 which impart discontinuities to the slope. The screen is tensioned by toggle levers 12 and is mounted in a housing 6 which in turn is mounted on the ends of a belt-driven out-of-balance shaft 2 horizontally disposed in a stationary casing 1. The material to be cleaned is fed onto the screen 11 via a tube 7, an adaptor casing 8 and a vertically adjustable distributor box 9. The material which does not pass through the screen falls on to aprons 14 which direct it to the classifiers 17, the run-off edges of the aprons being serrated to facilitate distribution of the material. Upwardly convergent bodies 15, 16 are mounted below and above each of the apron serrated edges to reduce turbulence in the air stream flowing upwardly through each classifier. The classifiers may be connected to a common suction fan. The cleaned material falls into collecting tubes 21 which merge together further down.