GB288259A - Improvements in or relating to tubular grinding mills - Google Patents

Abstract

288,259. Krupp Grusonwerk Akt.-Ges., F. April 7, 1927, [Convention date]. Ball and like mills.-Tn a tubular grinding mill an annular closed chamber containing the screening device 11 is arranged at the discharge end of the grinding chamber, the partition 7<1> between the grinding chamber and screening chamber being provided with openings 10 for the passage of the ground material into the screening chamber, outside which screening chamber is an annular collecting chamber 9 for the finely ground material, which is conveyed to circumferential openings 15 in the hollow transverse wall from the interior of which it is discharged by scoops 5 to the next grinding chamber. The screen chamber 6 is bounded by stepped grinding plates 7<1>, 7<11>, and the exterior casing of the mill and is subdivided into single screening compartments 9 by transverse partitions 8. The ground material falls through the holes 10 in the grinding plate 7' on to the screen 11, the oversize particles passing through the slot 12 into the grinding chamber on the rotation of the mill in the direction X. The screened material falls on the bottom plate 13 and is conveyed by the fixed guides 14 to the opening 15 in the drum 3 from whence it is raised by the buckets 5 to the space 4 and thence into the fine grinding chamber 2. The grinding surface 17, Fig. 3 may be conical and the oversize particles are returned into the grinding chamber through holes 18 by means of ledges 22 during the rotation of the drum.