GB291702A - Improvements in roller grinding mills - Google Patents

Abstract

291,702. Moog, O. Jan. 2, 1928. Roller mills. - In order to maintain a substantially constant level of grain or other material in a container disposed above the rollers of a grinding-mill, the flow of material from the container u, Fig. 1, to the rollers a is regulated by means of a movable element i<1>, which is mounted in the container and the position of which varies with the rate of discharge, the element controlling the operation of a servo-motor or like device by which the opening or closing of the feed-plate d is effected. The element i' preferably comprises a series of radial arms i of circular or inverted-V cross-section arranged in spiral formation and mounted on a common spindle, the upper arms being longer than the lower arms and the element being pulled downwardly against the influence of a spring k to an extent depending upon the flow of material. The movement of the element i' is communicated through a crank l<1> on a rotary shaft l a second crank m, a connecting- rod n and bell-crank lever o, to a movable spindle w adapted to open or close an orifice x of the servomotor device. This device comprises an outer container r, Figs. 3 and 4, in which oil or other fluid is continuously circulated through passages z and the orifice x by a pump y<1> driven from the roller mill, and an inner container v fitted with a piston h and having a port v<1> leading to the outer container. When the orifice x is closed by the valve stem w, the piston h is depressed by the pressure of the oil &c. and, by means of a pivoted lever f, lifts a rod e, thus rotating a shaft c and raising the feed-plate d connected thereto. A screw v<2> for varying the size of the port v<1> regulates the rate at which the piston is depressed. Should any stoppage occur in the operation of the mill, the pump y<1> ceases to act and a counterweight t on the rod e moves the feed plate d to its closed position. The point at which the bell crank lever o engages the valve stem w is adjustable by a nut o<1>, while a second adjustable nut o<3> determines the extent to which the feed-plate may be opened. If no adjustment of the feed plate is desired, the bell-crank lever o may be clamped in a fixed position by a nut o<7> co-operating with a slot o<5> in a sector o<6>.