GB463191A - Improvements in and relating to pulverizer mills - Google Patents

Abstract

463,191. Ball - and - ring mills. TRAYLOR ENGINEERING & MANUFACTURING CO. Sept. 23, 1935, No. 26277. Convention date, Oct. 1, 1934. [Class 59] In a mill having at least two grinding stages the first grinding stage is arranged on the upper side of a fixed grinding ring whilst the second stage is arranged on the underside of a fixed grinding ring, the rotatable grinding ring of the second stage being suspended from the rotatable grinding ring of the first stage to increase the load on the latter. As applied to a mill for the dry grinding of materials the row of balls 29 of the first stage is supported on the upper surface of a fixed ring 6 and the balls are driven by a ring 26, and the balls 30 of the second stage run on the underside of the fixed ring 6 and are driven by a ring 27 which is supported by rods 31 from the ring 26. Springs 32 on the rods 31 adjust the pressure of both stages. The rings 26, 27 are loosely connected and driven by a shaft 22 connected to a speed reduction gear comprising an internally toothed ring 20 geared to two idle wheels 17, 18 which are driven by a pinion 16 connected to the driving shaft of a motor 11. A shaft 40 passes through the hollow shaft 22 and drives a discharge fan or pump 37 at its bottom end. A feed gear 14 is driven by the motor 11 and the material falls to the outside of the balls 29. The material passes through these balls and is ground, it then passes from the inside to the outside of the row of balls 30 and is more finely ground, the fineness varying according to the height of an adjustable ring 34. The finished material then falls across openings 36 in the casing to a grid 39 and is discharged with the incoming air through the fan 37. When the mill is used for wet-grinding the holes 36 are closed and the fan replaced by a pump. An additional ring similar to 34 is placed inside the upper row of balls and a water supply pipe fitted. In a three stage mill for grinding damp materials the rotary rings are perforated for the ascent of a low velocity current of hot air, a ring being placed on the upper rotary ring to prevent material falling through the rings. This counter current of drying air is drawn from a casing surrounding the holes 36, the air for drawing off the ground material by the fan 37 is also obtained from this casing.