Patent GB-207094-A (GB)
Title: A process and apparatus for the separation of dry materials
IPC: B03B4/02
Filed: 1923-02-20
Abstract: 207,094. Sutton, H. M., Steele, W. L., and Steele, E. G. Feb. 20, 1923. Pneumatic separating; separating by shaking apparatus.-In a process for separating a mixture of dry materials of different specific gravities of the kind in which stratification of the materials is effected by the application of a shaking movement combined with the action of air forced through the materials under pressure, the materials are caused to flow initially in a single stream so as to concentrate the heavier constituents in the central zone and to discharge the lighter constituents at the sides, the main stream being thereafter directed into one or more channels at an angle to its original direction where the final stages of separation are effected. The apparatus comprises a table 1 of substantially Y-shape in plan mounted in a frame to which vibratory movements are imparted by a crank or eccentric rod 12 driven by a variable gear mechanism. The frame is supported by toggle plates 4, 5 which are retained in their seats by bent springs 16 and bolts 18 passing loosely through the springs and having projections 19 rocking on the under sides thereof. The floor of the table is formed of pervious material 30, Fig. 17, supported on bars 28 with an upper and lower covering of coarse mesh netting 29, 31. Air controlling strips 33 are disposed between the lower netting 29 and the floor. In a modification Fig. 11, the air controlling strips may be formed by the bases 82<1> of the riffles 32 carried on the upper surface of the table. The surface of the floor is of concave V- shape at its rear end, merges into a flat horizontal part about the middle of its length, and is of convex V-shape towards its forward end sloping downwards from its central line towards the sides. Preferablv the sides 54 converge towards the front end where the table divides into two branches 2, 3. In the main part of the table riffles 32 extend parallel to the sides and partly across the entrance to the branches, leaving unobstructed areas along the centre of the main part of the table and the front sides of the branches. Riffles 39 parallel to the direction of reciprocation of the table extend partly across the branches. The side plates and riffles continuously decrease in height towards the front end and at any position in the length of the table, they increase in height towards the sides. The front walls 42, Figs. 3 and 9, of the inclined branches are formed in sections 43 which can be swung on vertical axes to allow discharge of the lower stratum collected in this area into a shoot 50. A dividing wall 47 extends centrally and backwards from the. junction of the walls 42 and may be provided with a hinged rear part 47<1>. Fig. 23. which can be swung to one side to divert the stream into one or other of the branches. Baffle plates 55, 57 carried by the walls direct the air currents backwardly and downwardly to repel the lighter material. The compressed air is supplied bv a fan through a pipe 26 to two branches 25 with flexible air-tight connection to the. under side of the table. A wire mesh air-controlling strip 62 extends below the whole surface of the table and a second mesh strip 63 is supported below the first so as to provide clear air passages 64. An adjustable damper 65 is disposed in the pipe 26 to regulate the supply of air to the different parts of the table. The material is fed from an elongated hopper 36 to the rear end of the table which has upwardly-extending sides 37 for a short distance. The modification of the hopper shown in Fig. 23 comprises two sections g spaced apart at h and inclined upwardly and outwardly at a graduallyincreasing angleso as to convert the feed of material from a cross-wise to a longitudinal layer. The different grades of material are discharged over the sides at different points and are directed bv guide-plates 70, 71, 74 to different shoots.