Patent GB-206228-A (GB)
Title: Improvements in and relating to grinding and pulverising mills
IPC: B02C15/02
Filed: 1922-08-01
Abstract: 206,228. Portas, H. W. Aug. 1, 1922. No Patent granted (Sealing fee not paid). Ball-and-ring mills; roller- and-ring mills.-A grinding and pulverizing mill comprises a casing having a grinding- race within which are carried rotatable grinding-elements which bear freely thereon and are adapted to receive movement from a rotatable driving- member, some of the grinding- elements being connected with the driving-member and the remaining grinding-elements receiving movement from the grinding-elements rotated by the driving - member. As shown, the mill casing consists of a series of superposed cylindrical sections a<1>, a<2>, a<3>, a<4>, Figs. 1 and 2, mounted upon a base-plate a<5> and closed at the upper end by a cover-plate a<6> which supports the casing b' of a fan b. The driving-member d is carried by a vertical shaft c which is supported in ball or roller bearings c<1>, c<2> in the closed lower end of the section a<3> and the base-plate a<5> respectively, and is driven through bevel-gearing c<3>, f<2> from the driving-shaft f. The member d has a number of radially and downwardly inclined bosses d' the upper portions of which are cut away to form recesses for the reception of pivotally-mounted driving-elements e<1> which engage and drive the grinding-elements e. Balls h of less diameter than the balls e are disposed freely between adjacent grinding-elements e within the grinding-race g. The race g is formed of segments which are locked together at the adjacent lateral faces by bars g<2>, Fig. 3, engaging in V-shaped recesses in the faces of the segments. The upper outside edge of the race is engaged by a flange a<7> at the lower end of the section a<4>, an annular rib in the flange fitting in a groove in the edge of the race. An agitator fan i is mounted at the upper end of the shaft c within the section a<4>, and a hit-and-miss valve j, j<1> to control the volume of air extracted by the fan b is mounted at the joint between the section a<4> and the cover-plate a<6>, the movable disc j<1> being operated by a spindle j<2> connected by a crank j<3> to a stud on the disc. The spindle b<4> of the fan b is supported in a boss on the cover-plate b<3> and a bearing in a bracket b<@>, and is driven through bevel-gearing b<6> from a shaft b<7> driven by a belt f<4> from the shaft f. The blades of the fans b, i may be adjustable on their arms. The air carrying the suspended material passes by a conduit k<1> to a separator whence the air returns to the sectiona<2> of the mill by a conduit m<1>. The section a<2> is closed at the bottom and serves as an air chamber, the air passing to the section a<4> by way of slots or holes a<9> in the bottom plate of the section a<3>. peripheral grooves g<4> in the segments of the race g, and perforations a<10> in the flange a<7>. Director plates a" of triangular section are provided on the inner face of the section a<4> above the flange a<7>. The coal, ore, &c. is fed from a hopper o<2> into a shoot o<3> leading into the section a<4> by a screw conveyer o driven through gearing p<2> from an electric motor p<1> supported on a bracket p on the section a<4>. Inspection openings q with coverplates q<1> are provided in the sections a<1>, a<4> and in the cover-plate b<3> of the fan casing b<1>. Fig. 5 shows two mills a fed from a receptacle r. In the event of excess air pressure being produced in the separator system, relief is effected by pipes t<1> leading to an air collector t which is also connected by pipes t<2> with the discharge chambers s<1> of the separators s by which the pulverized material separated from the air is passed to the discharge conveyer s<2>. The driving-member and the agitator fan may be mounted on separate shafts driven from the same or different sources of power, and the material may be fed into the mill at more than one point of the casing. The grinding-elements may be of cylindrical or conical form.