GB460867A - An improved method of and mill for pulverizing - Google Patents

Abstract

460,867. Roller - and - - ring mills. INTERNATIONAL COMBUSTION, Ltd. June 9, 1936, No. 16122. Convention date, June 10, 1935. [Class 59] Deflecting vanes 77 are arranged in the mill casing to break up the whirling state of the material thrown off the rotating bowl 17 and to throw back into the bowl coarse material for regrinding. As shown, the rollers 43 are mounted on horizontal pivots 50 and are adjusted relatively to the revolving ring 18 by springs 54 acting on a lever-arm 52. Each spring 54 is housed in a cup 56 supported on an arm 55 on the casing 3, a follower 61 being moved up or down on a screwed sleeve 59 to adjust the tension of the spring. The rollers are spaced from the revolving ring 18 attached to the pan 17 which is mounted on a shaft 19 driven bv a worm and wormwheel 37, 33 housed in an oil-tight casing 22. Thrust bearings 31, 35 support the shaft 19 and a spiral groove 28 lubricates the upper bearing 5, the surplus oil returning by conduit 30, and a labyrinth packing 42 protects the bearing from dust. Material is fed to the centre of the revolving bowl by a shoot F, Fig. 2, and is thrown out onto the grinding ring where it is crushed and deflected by a ledge 78, Fig. 1, into a spiral air stream ascending in an annular space 76 around the pan, heavy material being deflected back into the pan by radial deflectors 77. Uncrushable material falls through the space 76 onto the bottom of the casing and is swept by pivoted blades 84 through an orifice 80, Fig. 2, where it meets an upwardly directed air stream from conduit 83, supplied from the main air conduit 72, or other source which conducts any fine material back to the mill, the uncrushable material being discharged through a pivoted flap 82. The fines are carried upwardly through holes 13 in the cover 4 into a separator K the sufficiently ground material which enters the cone 93 through deflecting plates 91 being carried off through outlet 92 whilst the material separated out falls to the bottom of the cone and is discharged through a shoot 15, covered by a weighted flap 94, into the pan.