GB468215A - Improvements in pulverisers - Google Patents

Abstract

468,215. Ball-and-ring mills. BABCOCK & WILCOX, Ltd. Dec. 30, 1935, No. 35983. Convention date, Dec. 29, 1934. [Class 59] In a ball-and-ring mill having upper and lower grinding stages in series with a discharge outlet at the top of the casing, means are provided for directing a stream of air upwardly through the casing in a flow path successively sweeping the material discharged from the lower and upper stages, and means adjacent to the discharge side of one of the stages for varying the velocity of the air stream. As shown the centre ring 13 is non-rotary and the upper and lower rings 12, 14 are driven by the shaft 15. Pressure is applied to the upper and lower rows of balls 19, 16 by springs 23 carried by a frame 24 secured to the top of the driving shaft 15. Material to be ground falls from a shoot 25 to the outside of the row of balls 19 and after being ground is discharged to the inside of the lower row of balls which completes the grinding and discharges the material centrifugally into an airstream ascending through an adjustable orifice 32. The airstream passes inwardly through orifices 35 in the centre ring 13 and then ascends to a discharge outlet 11, an adjustable bell 36 regulating at a restriction 38 the velocity of the air flowing past the inside of the upper row of balls 19. In a modification the centre ring 13 is driven by the shaft 15 and the casing 30 is bulged near the extremity of the conical baffle 39 to allow for any rocking movement set up by the ring 13. The bell 36 is adjustable from outside the mill bv the movement of a screwed rod passing through the cover. Valved openings may be provided in the baffle 39 and automatic means may actuate one or both openings 32, 38 in accordance with the quantity of air supplied.