GB678465A - Improvements in and relating to machines for propelling abrasives - Google Patents

Abstract

678,465. Sand-blast. JACKMAN & CO., Ltd., J. W., and NEVILLE, F. W. March 20, 1951 [March 23, 1950], No. 7244/50. Class 60. Apparatus for propelling abrasive comprises a hollow rotating member open at one side and with a divergent wall on which are mounted at intervals vanes of thick section, the rear faces being approximately radial and the front faces curved to ensure that the gaps between the blades will be smallest at the periphery of the rotating member. An impeller 5 made of hard cast metal has a diverging internal face 6 on the inside of the wall 7 which has vanes 8 cast integral with it. The vanes 8 are of thick section; the rear or following face 9 of each vane is approximately radial and the front or leading face 10 is curved so that the space between it and the next vane is narrowest at the periphery and widens to the inside of the impellor. The vanes 8 project above the top edge of the divergent face 6, and the spaces between them narrow from their bottom edges to the top edge of the face 6 so that abrasive falling on the face 6 from delivery pipe 11 is forced up a narrowing passage as it ascends the face 6 under centrifugal force till it is hurled out through the narrowest part of the openings 12 above the top edge of the divergent face 6. The impellor 5 is bolted to a driving plate 13 by three bolts 14, the underside of the impellor being provided with three projecting portions 15 around the bolts to contact a flat rubber ring 16 inserted in a recess in the driving plate 13. The outside of the impellor has three pads 17 fitting accurately within the machined rim of the plate 13; the projecting portions 15 are open at one side at 18 so that when the bolts 14 are slackened, the impellor may be given a small angular movement and released, thus facilitating renewal of a worn part. Abrasive material is fed to a hopper by gravity or an air stream or any other suitable means and passes down the delivery pipe 11 whose open end 23 lies parallel with the diverging wall 6 of the impellor 5; the side of the delivery pipe 11 is cut away on the leading side to discharge abrasive in the direction of rotation of the impellor. The discharge end of the pipe at 23 is placed so that it lies just within a circle bounded by the inner edge of the vanes 8. More than one abrasive supply pipe may be used; they may be fixed or adjustable about the centre of the impellor to vary the point of inlet and therefore of discharge from the impellor. Specification 469,451 is referred to.