Patent GB-1369737-A (GB)
Title: Sorting apparatus including a rotary fluid-blast mechanism
IPC: B07C5/36
Filed: 1972-09-14
Abstract: 1369737 Pneumatic separation SPHERE INVESTMENTS Ltd 14 Sept 1972 42780/72 Heading B2H [Also in Division G1] An apparatus for sorting objects, e.g. pieces of rock containing ore and/or waste, comprises means 10, Fig. 1, for moving objects 14 to be sorted along a path; nozzles such as 37, Fig. 5, for providing a blast of fluid; means for moving the nozzles adjacent said path, the nozzles being capable of moving at a lower speed than the objects so as to reduce the relative velocity between the objects and the nozzle immediately adjacent said path to a fraction of what it would have been with a stationary nozzle; and means for controllably supplying fluid through a selected nozzle to deflect a selected object from said path.  The pieces of rock 14, Fig. 1, are fed in a single row on to a conveyor belt 10 which discharges them at the belt head pulley 11 so that they pass in a fairly flat trajectory over a guard plate 15 and over a rotary fluid blast mechanism 16 which incorporates the nozzles 34 and which is driven from the pulley 11 at a lower speed than the belt. A detector 20 detects one or more properties of each piece of rock and provides signals indicative of these properties to a decision unit 21 which decides, whether or not a particular piece of rock is to be rejected. If so, it provides an appropriate signal to a timing stage 22 to which is connected a belt speed monitor 23 providing an indication of belt speed. The timing stage in turn provides a signal to a gating unit 24 which operates one of a number of valves 25 to supply compressed air from a source 26 to a nozzle in mechanism 16 when that nozzle is moving adjacent the path of the pieces of rock and the particular piece of rock is in front of that nozzle so as to create a blast of air to deflect that piece of rock along a path passing above a splitter plate 17. Pieces or rock which are not to be deflected follow their normal trajectory to the underside of plate 17. The nozzles are in the form of transversely extending radial slots in the outer peripheral portion of a rotatable disc 31, Figs. 5 and 6, the radially inward end of each slot opening into a transverse pasageway, e.g. 43, which is closed at one end and which is aligned with one of a number of openings in one or the other of side plates 32, 33 which are mounted to, and rotate with, the disc 31. Stationary air supply manifolds 47, 48 are mounted closely adjacent the plates 32, 33. Openings in the manifolds communicate with respective curved grooves, such as 53, 54, 55 on the walls of the manifolds adjacent the side plates and are connected to air lines, such as 56, 57, 58. By supplying compressed air to any one of the air lines, a blast of air can be caused to issue from any nozzle that is passing the corresponding opening in the manifold as the disc 31 rotates. For ensuring that the air blast occurs at the proper time, a light source 64 is mounted on a pivotable bracket 63, Figs. 5 and 6, adjacent the periphery of the disc 31 for directing light into each slot in the disc as that slot passes the light source. Photocells 65-67 and 68-70 are mounted in the bracket 63 adjacent manifolds 48 and 47 respectively and are positioned directly opposite arcuate slots in the manifolds, such as slots 60-62 shown in manifold 68. The photocells are connected to timing stage 22. Thus, when a particular slot passes the light source 64 light is transmitted through the slot and into a corresponding passageway in the disc 31. This light is detected by one of the photocells 65-70 which will transmit a sequence of signals to the timing stage 22 allowing the latter to start and stop the flow of compressed air to the slots or nozzles at the appropriate time. To adjust the timing the bracket 63 may be moved up and down as shown by the arrow in Fig. 5 to a limited extent corresponding to the extent of the arcuate slots in the manifolds 47, 48. Suitable circuitry for the gating unit 24 and timing stage 22 is described.