GB248711A - Improvements in or relating to furnaces for roasting sulphide and other ores - Google Patents

Abstract

248,711. Bracq, E. March 9, 1925, [Convention date]. Roasting-jurnaces; charges, agitating. - In a roasting- furnace having superposed hearths, or a continuous hearth of helical form, the mechanism for imparting a combined horizontal and vertical movement to the rabbles is contained within a large movable central chamber, which is easy of access and where the mechanism .can be kept cool. As shown in connection with a helical hearth furnace the rabble arms 41 are carried by a central shaft 39 and are counterbalanced by a weight 8 suspended from a cable passing over pulleys 6. In line with the shaft is a pillar 15 screwed externally to the pitch of the hearth, and the nut 17 working in conjunction therewith is bolted to a platform 9, which can be rotated in -either direction by a bevel wheel 19 and teeth 18 formed on a helical surface. On the platform 9 are mounted a framework 10 carrying the inner closures for the hearth chambers, and mechanism for giving the rabble arms a combined up and down and oscillatory movement, which is superposed on the continuous helical movement produced by the nut 17. This mechanism comprises a motor 33 which drives continuously a shaft 24 carrying an eccentric 27 and a crank - disc. The eccentric imparts a vertical reciprocation to the shaft 39 through the lever 34 and collar 38, while the crank disc oscillates a sleeve 43 feathered on the shaft. During the descending helical movement of the rabble arms, the up and down movement of the shaft 39 from the eccentric 27 is stopped by the withdrawal of a pin 48 on the eccentric arm 28 into a slot 61 on the lever 34, in which it can oscillate freely. The withdrawal is effected by the contact, with a fixed stop 60, of an arm 59 on a shaft 56. Rotation of this shaft throws over a weighted lever 55 and moves the pin 48 through the links 49, 52 and lever 50. The platform 9 and the mechanism carried thereon are counterbalanced by weights 66. The rabble arms 41 are bolted to slides 77, which are engaged with guide portions 78 on the holder 40, and are cooled by air, which may be supplied through the pillar 15 and the hollow holders 40. The closure members for the hearth consist of metal sleeves 69 carried by ring members 11 on the framework 10. The screens are covered on one side with sheet asbestos and on the other with insulating material 72, and may be formed with air supply and inspection apertures. Specification 20108/12 is referred to.