GB561200A - Improvements in or relating to gyratory crushers - Google Patents

Abstract

561,200. Grinding and crushing mills. NORDBERG, M'F'G. CO. Aug. 1, 1941, No. 9820. Convention date, Aug. 3, 1940. [Class 59] In crushers with gyratory heads, particularly of the type described in Specification 243,926, [Class 59], and United States of America Reissue 19154, in which the crushing cavity is between an overhanging bowl and a gyrating outwardly flared head, the feed of material to the crushing cavity is controlled so that particles to be crushed are fed to the head at the top of the crushing cavity along paths generally perpendicular to the face of the crushing head at the top, thus bringing them to a stop there, the radial width of the top of the cavity being restricted to limit the material admitted at one stroke to a mass not greater than that discharged from the bottom of the cavity at each stroke. In carrying out the control, an excess of material accumulates above the crushing cavity and forms a continuous bridge over it from which the feed is derived. The bowl has an outer wall 5 and two inner conical walls 6 and 7 and is thus of a hollow annular box form in which are webs 8 to which are locked bolts 9 carrying lugs 13 formed on the bowl liner 12. Access apertures 16 are covered by closures 17 and over all is superposed a conic deflector 18. The grinding head 28 on a shaft 50 mounted eccentrically in a sleeve 22 rotated by gearing 23, 24 from a driving shaft 25 seats against a spherical bearing member 27 and carries a crushing mantle 29, kept in position by a locking ring 30 screwed to a locking member 31 fixed to the head 28 by bolts 32 and extending upward to carry a support 34 for a feed distributing plate 35, over which is aligned a feed shoot 36 mounted by transverse members 37 and adjusting nuts on vertical supports 38. Above the locking ring 30 is mounted a continuation 45 forming an inward conical deflector between which and the deflector 18 is an opening flared widely enough to prevent any crushing action. An annular collar 75 resting on the wall 7 completes with the liner 18 and the cone 45 a hopper leading to the crushing zone. The angle of the head 28 is higher than the angle of repose of the material treated and the action is that material delivered from the feed plate 35 is passed on by the cone 45 along paths at right angles to the face of the head, the material forming a moving bridge over the gap between the grinding head and its fixed surroundings, and the particles gradually falling with a reduced initial acceleration through successive positions such as I, II, III, IX, Fig. 3, until they arrive at the crushing position past the line X-Y, the crushing gap being radially such as to admit a mass as described above. Reference is also made to U.S.A. Specification 1,537,565.