GB376760A - Improvements in or relating to apparatus for pulverising or grinding coal and other materials - Google Patents

Abstract

376,760. Impact pulverizers. FEUERHEERD, E., 47, Victoria Street, London, and HENDERSON, T. H., Queen's Buildings, Swansea. March 5, 1931, Nos. 6862, 14643, and 30303. [Class 59.] Apparatus for pulverizing coal &c. comprises superimposed propeller plates, rotated preferably in opposite directions, which throw the particles of material by centrifugal force into contact with one another outside the periphery of the impeller plates so that pulverization takes place mainly or entirely outside the impeller plates. As shown the apparatus comprises discs 2, 3 rotated in opposite directions by motors 8, 10, or a single motor may drive the discs and feed conveyers through gearing. The discs are provided with vanes 13, 16 and the rims are protected by annular rings 17, 17a. Material is fed to the lower disc through the hollow shaft 4 of the upper disc and the upper disc is fed through shoots 12. The material to be ground is discharged by a tube 35 to a band conveyer 32, scrapers 33 deflecting some of the material on to trays 34 which directs the material into the passage 12 whilst the remaining material is discharged into the hollow shaft 4. Coarse material from the discs is collected into a hopper 38 and is returned by a bucket conveyer 36 back to the feed inlet of the mill. The shaft 4 is mounted in a bearing 27 which is prevented from rotating by sliding rods 29 and is moved longitudinally to adjust the spacing of the grinding discs by a worm 24 and wormwheel 23. The material is thrown outwardly by the discs and is disintegrated primarily by mutual impact just outside the peripheries of the discs. An annular shelf 18 with partitions 20 surround the discs and collects ground material against which the material from the discs is further disintegrated. The shelf may rotate or a fixed or movable surface may be provided outside or surrounding the discs. The fines are carried off by an air draught through openings 43 which may be covered with a screen and are discharged through an opening 44. The lower disc 3 is provided with a shroud ring on the top of the ribs to limit the fan action thereof. The shoots &c. may be made airtight so that the grinding may be carried out under a vacuum or subatmospheric pressure.