Patent GB-750432-A (GB)
Title: Centrifugal blasting apparatus
IPC: B24C5/06
Filed: 1953-07-28
Abstract: 750,432. Abrasive blasting. PANGBORN CORPORATION. July 28, 1953 [Sept. 23, 1952], No. 20877/53. Class 60 [Also in Group XXVI] A centrifugal throwing wheel assembly for projecting blastant particles comprises a throwing wheel 20 having a rotating shaft 30 carrying a runner head 32 upon which throwing blades 34 are mounted; the shaft 30 ends in an enlarged flange 36 to which the head 32 is bolted. The runner head is of massive construction so that unsymmetrical erosion of the throwing blades will not significantly unbalance the unit dynamically. The blades have enlarged dovetail edges 37 received in corresponding slots 39 in the face of the runner head. The outer ends of the blades are reinforced by ribs 41, 43, the rib 41 providing a support having a bearing edge 45 which rests against the face of the runner head so as to provide a more substantial blade backing, and the rib 43 strengthening the outer edge of the blade. Each blade is fixed by a pin 38 fitted into sockets 47, 49 in the enlarged dovetail edge of the blade and the face of the runner head. A discharge-directing feed cage 40 has a flange 42 secured by clamps 51 to a housing 44 which is anchored to a base plate 46. The bottom of the cage has a central aperture 50, and its side has a feed slot 52. Within the cage is an impeller 54 having vanes 56 and a cylindrical boss 58 passing through the aperture 50 of the feed cage and fastened to the runner head by a central bolt 60. Blastant particles are supplied to the hollow interior of the impeller 54 by a spout 62 fastened to the housing 44. The spout 62 is held in place by a set of three pins 61; two of the pins pass through aligned openings in a bracket 63 fastened to the housing and a plate 65 integral with the spout; the third pin 61 is carried in a lip 67 opposite plate 65 on the outer edge of a collar 69 formed integrally with the spout and fits into a groove 71 in the flange 42 of the cage. A rib 73 on this flange shows the normal position of the cage with respect to the pin 61. The cage also carries marks 75, 77 on opposite portions of flange 42 co-operating with a scale 79 secured to housing 44 in either of two alternative positions.  The housing 44 is secured to base plate 46 by bolts 91 threaded into the plate and holding down a part 93 of the housing. A tubular enclosure 101 for the shaft 30 has a flange 103 secured to the housing by bolts 105; the enclosure is also supported by outwardly projecting wings 125 integral therewith bolted to angles 127 secured to the base plate 46. The shaft 30 projects through a seal 107 and carries a drive pulley 109. The enclosure 101 accommodates bearings 121, 123. Bearing 121 is a twin row roller bearing and ingress of foreign particles is prevented by meshed shields 131 132; shield 131 is fixed on boss 135 on shaft 30 and shield 132 is secured by bolts 137 to the enclosure 101, the shields being formed with interfitting annular ribs 133, 134. Any foreign particles making their way to the shields will be projected outwardly if they contact with the rapidly rotating shield 131; an escape aperture 143 is provided in enclosure 101. The inner edge of shield 132 where it opposes either the outer surface of the shaft or a ledge 145 of shield 131 is provided with spaced grooves 147 to trap the particles. A lubrication passage 151 is provided; to direct excess lubricant through the space between shields 131. 132 additional shields 153, 154 with meshing ribs are placed on the far side of the bearing. Bearing 123 is protected by a shield 107, fixed to the enclosure, and a pair of rotary shields 161, 162, the cooperating faces of the shields providing a labyrinth. The runner head 32 has its rear face shaped to provide a rib 170; a pair of annular guards 172, 174 are secured to the inner wall of housing 44; either or both of these guards being interrupted in the lower or discharge portion of the wheel. The guard rings 172 174 are mounted on wear panel sections 181, 182, 183 which cover the housing wall through which shaft 30 projects, and are secured thereto by bolts passing through apertures 185; the panels project out through the bottom of the housing to form an extension thereof. The opposing wall of the housing 44 is provided with a similar set of wear panel members. The upper edges of the wear panel members are shaped to provide a generally convex top and flat sloping sides. At the lower portions of these sides, the wear panels have bolted or riveted thereto hooks 190 in which are set a pair of end wear plates 192 resting along the flat tapering edges of the side panel members, but not positively fastened down. Their upper ends are held under the edges of an arcuate wear lid 194 resting on the convex top of the side panels. The lid 194 has on its concave lower surface a pair of ribs 196, and at each end carries an overlap extension 198 closely engaging the upper end of plate 192, The upper convex surface of lid 194 has a longitudinally extending central rib 200 with holes 202 to facilitate handling, and a transverse strengthening rib 204. The lid 194 engages a cover 211 closing the upper portion of housing 44 and providing access thereto. The cover is held on the housing by hinges 212 and manually operated clamps 214 and carries a gasket 230 held in place by a plate 232 secured by bolts 234; the lower ends. of which contact the ribs 200 of wear plate 194. The base plate 46 may be mounted on an inclined surface so that the shaft 30 is inclined to the horizontal, and also so that the housing 44 is rotationally adjusted about the axis of the shaft 30. Adjustment is effected' to maintain the spout 62 substantially vertical. U.S.A. Specification Re-issue 20,538 is referred to.