GB117281A - Improvements in Grinding or Crushing Machines. - Google Patents

Abstract

117,281. Miller, D. J. G., and Lloyd, R. A. May 26, 1917. Roller-and-ring mills.-In a centrifugal roller mill, rollers 3 co-operating with a stationary ring 2 are rotatable on pivoted carriers 5 mounted on a rotating table 1 which forms the bottom of the pan, the pivots 6 of the carriers being arranged below the table and permitting the carriers to move radially to the table. The table assists in carrying the material round, and is provided with vanes for throwing the material into the bites of the rollers and against a screen 24 arranged in a casing 27. The table is secured to a shaft 21 mounted in a bearing 22 and an adjustable footstep 20 and driven by a pulley 100 or gearing, which may be arranged above the table. Cups 50 exclude dust from the bearings. The carriers 5 are secured to a socket 76 pivoted on a pin 6 which is formed with a tapered shank fitting a slot 78 in a bracket 7 on the table 1. The socket is engaged by an adjusting- screw 10 and the shank carries a clamping-nut. The carriers may rest on rubber or spring cushions in the sockets. The carriers are supported laterally by guides 8 on the table; the guides at one side may be mounted resiliently. The pressure of the rollers on the ring can be regulated by springs in connexion with the carriers. Stops may be provided for limiting the movement of the carriers towards the ring. The carriers pass through slots 71, Fig. 5, formed in the table and provided with closures which permit of the radial movement of the carriers. As shown, the closure consists of a rubber sheet 72 which is secured in the slot 71 by a frame 73 and is secured to the carrier by a ring 74. The closure may consist of a flexible metal plate. The grinding-ring 2 may be secured to a frame 4, consisting of spaced rings connected by webs 4<x>, which is detachable secured to a bed 12 by keys 14 and by bolts passing through the webs. Packing may be arranged between the table and the frame 4. The packing may consist of rings 17 and a spring-pressed ring arranged in a groove 15. The rollers and the ring may be cooled by water. The material is fed on to the table through a tube 38 provided with an adjusting-cone 37. The table carries inclined vanes 85, 86 for delivering the material to the bites of the rollers and to the screen 24 respectively. The vanes may be pivoted on pins 87 and be arranged to swing centrifugally against stops 88. The vanes 86 may be adjustable in length and be provided on the side adjacent the ring 2 with a flange, the adjustment determining the height at which the material is thrown against the screen. The screen may consist of detachable rings, which may be of different meshes. To prevent coarse particles from striking the screen, a guard-ring, shown as a bevelled part 4<xx> on the ring 4, may be arranged round the lower part. The table may carry one or more brushes for cleaning the screen. The brushes are vertically and radially adjustable on standards on the table. The material passing through the screen falls into a trough 16, arranged on the stationary bed 12 and provided with delivery openings. The table carries fan blades 19 for discharging the material and drawing air through the screen. The table may also carry blades 89 and a cowl for forcing air through the screen. Fan blades may also be provided on the rollers For treating wet material, the mill may be provided with a central feed-chamber having spouts for delivering the material in front of the rollers. In this case, the table 1 may be provided with doors for delivering a batch of material; or the material may be lifted out of the pan by rotary radial scoops which are raised out of the pan during the grinding operation.