| 摘要 |
901,228. Ball-and-ring mills. FRENKEL C-D CO. Ltd. June 3, 1960 [June 5, 1959], No. 19305/59. Class 59. In a mill comprising a ring of balls supported on an upwardly facing annular track of concave cross-section, means are provided for guiding and loading the balls against the track which comprise at least one ring coaxial with the track and engaging upper parts of the balls outside their pitch circle and applying to the balls pressure towards the track with a radially inward component, and means are provided for effecting relative rotation between the track and the loading ring about the centre of the track. There may also be provided at least one ring coaxial with the track and engaging upper parts of the balls inside their pitch circle and applying to the balls pressure towards the track with a radially outward component. The loading rings may be operated simultaneously or selectively. As shown, three balls 20 are loaded against a track 18 on a rotary table 15 by means of outer and inner rings 22, 23 respectively. The radially inward component from ring 22 is greater than the radially outward component from the ring 23 by an amount which balances or exceeds the outward centrifugal force on the balls. The mill casing 10 is provided with an inlet 9 for carrying and drying air and an outlet 11 for particle bearing air leading to a classifier. The casing also has an inlet shoot 12 for material to be pulverized and an inlet pipe 13 for compressed air which may be heated. For guiding the rings 22, 23 and holding them against rotation, each ring is provided with three equally-spaced radial arms 36, or 37, which pass outwardly through slots 35 in the casing, each arm having at its radial outer end rollers 40, 42 which run on fixed guides 41, 43. The weight of the rings 22, 23 may be varied by adding rings 22a, 23a. In modifications, the loading of the rings on the balls may be varied by means of hydraulic or pneumatic rams or by means of springs. In a further modification, the track is stationary and the loading rings rotated. |
