GB469740A - Improvements in and relating to roller and breast grinding mills - Google Patents

Abstract

469,740. Roller - and - breast mills. CARRUTHERS, C., and TORRANCE & SONS, Ltd. Jan. 29, 1936, No. 2755. [Class 59] In a mill having three or more grinding bars in contact with the roll, the third or following bar is set for finer grinding than the preceding bars and the pocket between each pair of bars is provided with a relief orifice which releases part of the pressure of the material in the pocket. As shown in Fig. 1, the breast bars 1 ... 4 are mountec in a hopper throat having a constriction 9, as des cribed in Specification 376,459, and are separ ated bv bars 5 which to gether with the grinding bars form recesses 7 ir which material accumu lates at a high pressure which varies with the speed of the roll 6 and is regulated by relief orifices 8a, 8b, 8c leading through the end sealing ring 7a into a common valve-controlled channel or communicating with a preceding recess. The pressure on the grinding bars is controlled as described in Specification 469,747, by hydraulic plungers 17, 18, the pressure on the bar 4 which is the fine grinding bar being greater than the others, the intermediate bars 2, 3 bearing with little or no pressure on the roll. The length of the grinding bars may vary as described in Specification 469,741. The pressure on the grinding bars may be independently applied by screwed bolts or as shown in Fig. 9 the bars 1 ... 3 may be housed in a sheath 21 and pressure applied by a spring 23, the pressure of which is regulated by a screw 28, the fine grinding bar 4 being individually adjustable by a screwed rod.