Patent GB-185696-A (GB)
Title: Improvements in or relating to mills for grinding cocoa and similar substances
IPC: B02C7/17
Filed: 1922-01-05
Abstract: 185,696. Halliwell, T. Jan. 5, 1922. Disc mills.- A mill for grinding cocoa &c. comprises pairs or sets of millstones each having differently-formed grinding-surfaces, the first stage stones comprising an exterior ring of stone grooved in separated sections and a central portion of steel finely-grooved in separated sections, the second-stage stones being formed of stone throughout divided into separate sections over the whole surface and grooved to a coarser extent than the steel sections of the first-stage stones, and the subsequent or finishing stones being formed of an exterior ring of plain or smooth stone, and a central sectioned stone portion grooved to a finer extent than the second-stage stones. A mill with three sets of stones b, b<1>, Figs. 1 and 3, enclosed in a casing c with doors is shown. The cocoa beans are fed from a hopper d by a rotating fluted feed-roller d<1> through a shoot d‹ to the hopper e of the first pair of stones, and. the ground material passes by a spout h to the next set of stones. Each stone of the first set consists of an exterior stone ring e<1>, Fig. 7, and a central steel disc e<2> formed of sections divided by tangential grooves e<3>, each section being finely grooved in a different direction to the adjacent section. The upper or running stone b carries a metal ring g<3>, Fig. 5, in which rest trunnions g<4> formed on a ring g<5> which encircles the driving-spindle g and is engaged by the trunnions g<7> of a bridge - piece g<6> secured to the spindle. The lower stone b<1> is mounted in a pan f<2>, and a cover f encloses the upper stone. The plate e<2> of the upper stone is backed up with concrete or cement at f' and adjustably mounted in the stone by studs f<4> extending beyond the iron hoop or cover f<5>. The plate e<20> of the lower stone is hollow to receive steam supplied and discharged through pipes f<6>, f<16>. The pan f<2> is made hollow or jacketed and steam is supplied and discharged by pipes f<7>, f<17>. The lower stone may be ad. justable in the pan by means of screws passing through bushings in the double walls of the pan. Steam is supplied and discharged by pipes g<2>, g<12> to the jacketed bush g<1> through which the spindle g parses. The whole surface of each stone of the second set is of stone divided into sections b<3>, Fig. 8, by a number of tangential grooves b<2>. Fig. 9 shows a plan view of one of the stones of the third set; the outer plain ring or skirt of stone b<4> and the inner disc b<5> of stone are divided into sections by tangential grooves b<6>. The spindles g are driven through bevelgearing j, j<1> from the main shaft d<4>. The upper stones are adjustable simultaneously by means of a bar k provided with wedges k<1> engaging rollers k<2> carried by blocks k<3>, Fig. 6, in which the lower ends of the spindles rest. A nut l<1> on the screwed end of the bar k is mounted in a pinion l<2> which gears with a wbeel l<3> on a handshaft l<4>. Means may be provided for independent adjustment of the stones, and a detachable crane for use in handling the stones may be provided to fit in a socket on the machine frame. Fusible plugs may be fitted in the null to control an alarm or water or steam supply in case of fire or overheating of the stones.