GB1085800A - Improvements in or relating to shot-blasting and like equipment - Google Patents

Abstract

1,085,800. Blasting. BRITISH STEEL CASTINGS RESEARCH ASSOCIATION. June 10, 1966 [June 15, 1965], No. 25187/65. Heading B3D. [Also in Division H1] Shot-blasting equipment for use with ferromagnetic blasting particles comprises a rotor having a face normal or substantially so to its axis, the face containing the symmetrically disposed pole faces of at least one magnet and means for feeding near to the centre of the face particles to be held to the face by magnetic attraction so that they rotate with the face and are carried to and flung from the periphery of the face by centrifugal force arising from the rotation of the rotor. A shaft 2 rotated by V-belt drive to a pulley 17 carries rotors 1A, 1B consisting of mild-steel backing plates 12 carrying coils 13, pole plates 14 and slip rings 18 for the coils. Spout blasting medium and material removed from the workpieces are passed by an elevator (7) to a separator (8), the re-usable medium passing through a demagnetizing coil (10) to remove residual magnetism and thence to a bore 9 extending from one end of the shaft 2 having slots 20 in register with the gap 15 between the rotors. The polepieces may be sector-shaped (25, Fig. 5) or concentric (25A, Fig. 6) with flexible sealing members (26, Fig. 5 or 26A, Fig. 7) therebetween to exclude shot. Permanent magnets may be used. To control the arc of discharge from the rotors the medium may be supplied through a single slot in a non-rotating member in register with the gap 15; a rotating impeller may be mounted within the slot-containing member. If a single rotor is used the supply pipe (11) is suitably orientated. The direction of flinging may be controlled by a pick-off magnet. A permanent magnet (27, Fig. 8) narrow enough to enter the gap between the rotor faces is carried by a block (28) mounted between arcuate plates (29) with arcuate slots (30) for adjustment of the magnet. The magnet has a mild steel pole-piece 31 with a projection having one face (32) radial and another edge (33) inclined to concentrate the magnetic field.