GB1352836A - Method and apparatus for classifying particulate material - Google Patents

Abstract

1352836 Classifying particulate material F K MOGENSEN 28 May 1971 [23 July 1970] 35794/70 Heading B2H In a method of classifying particulate material according to size, the material is fed through a succession of classifying units, each unit including a frame carrying a series of obstacles with a spacing between adjacent obstacles greater than the maximum dimension of the largest particles arriving at this unit, whereby the larger size particles have a greater probability than the smaller particles of being obstructed and deflected laterally by the obstacles, the particles thus leaving a unit spreading out as streams having different directions according to particle size, Fig. 2, with at least a part of the spread of streams leaving one unit passing directly into a further unit without undergoging any disturbance to the spread during transfer between obstacles of the two units in question. As shown in Fig. 2, three units are arranged one below the other and one unit is arranged laterally of the first unit to effect sharp separation of coarse particles. The units may be stationary or at least one of them may be vibrated, and the amplitude and/or frequency of vibrations of the various units may be the same or different. The spacing between the obstacles may be the same or different in each unit. The obstacles may be in the form of elements of screens or grids Inclined to the horizontal and the inclinations may be the same for all the screens or grids in a unit or differ in a given unit, e.g. the lower screens or grids being arranged more steeply. Again the inclination of the screens or grids of different units may be the same or different. As shown in Fig. 3, two classifying units 1 and 2 are arranged one above the other. The units may be interchangeable to select optimum spacing between obstacles for a particular classifying operation. The sides 3 of each unit are strengthened by bars 4 and the units are suspended from springs 6. Vibrators 5 for each unit are located at the sides or beneath each unit outside the flow of the particles. The particle movement, instead of being by gravity, may be induced by centrifugal force.