GB191411743A - Improvements in or relating to Ore Roasting Furnaces. - Google Patents

Abstract

11,743. Bracq, E. May 13, 1913, [Convention date]. [Addition to 20,108/12.] Charges, agitating.- The operating-mechanism for a rabble arm, which stirs and moves the ore in the manner described in the parent Specification, is situated wholly outside the furnace. As shown in connexion with a furnace having a helical hearth, the rabble arms 4, 5 are carried by a shaft 1, the portion 10 of which outside the furnace is formed as a screw passing through a nut 27, suspended by links 28 and a rod 11 from a counterweighted beam 12. The nut is rotatably carried in a collar 28<1>, Fig. 4, and is formed with vertical grooves, with which engage collars 39 on a rod 39<1> free to move longitudinally between fixed stops. Motions of reciprocation in a vertical plane, and of rotation through a small angle, can thus be given to the shaft 1 and the rabble arms independently of the gradual rise and fall due to the screw 10. At its upper end, the shaft 1 passes through a column 32, rotatably supported on a base 33 and driven from the main shaft 14 by a pinion 35, and the rotary motion of the column is imparted to the shaft 1 through pins on a collar 26 engaging vertical grooves 31 in the screwed portion 10. The collar 26 is rotatably mounted on the column and has secured to it straps 29, between which travels a slide block 30 carried by a crank 24, driven from the shaft 14 by bevel and spur gearing 17, 23. The crank 24 also operates bell-crank levers 25 secured to the links 28 carrying the nut 27. A clutch 18, automatically operated when the shaft 1 reaches its highest point, cuts out the gearing 17, 23, so that, during the downward travel, the arms move along a continuous helical path. The driving-shaft 14 is operated through pulleys 15, 16, the former giving a rapid motion during the downward inoperative movement of the arms, and the latter a slower motion during the working period. When the clutch 18 is in engagement and the driving-gear in operation, the continuous upward movement of the rabble arms over the helical hearth is modified (a) by the vertical reciprocation of the nut 27 by the levers 25, and (b) by the oscillation of the shaft through a small angle by the crank 24, and these movements are timed to produce the sequence of operations described in the parent Specification. For a furnace with superposed hearths, the screw 10 and the automatic clutchdisengaging mechanism are unnecessary. The portion of the shaft 1 within the furnace, anc the rabble arms, are cooled by the circulation of water supplied through the pipe 2.