Patent GB-190901791-A (GB)
Title: Improvements in or relating to Rabbles for Ore-roasting Furnaces.
Inventor: BRACQ-LAURENT EMILE
IPC: F27B9/24
Filed: 1909-01-25
Granted: 1910-01-25
Abstract: 1791. Laurent, E. Bracq-, and Moritz, R. June 3,1908, [Convention date]. Reasting-furnaces; charging charges, agitating.-In a furnace provided with superposed floors, and in which the material passes from one floor to the floor below through slopes 3, 4 at the sides or through a funnelshaped aperture 1 at the centre, the central vertical shaft is formed with an inner tube, and air under natural or forced draught, and with or withsut a spray of water, circulates as shown by arrows through the outer tube, the rabble arms, and hollow teeth, and finally passes into the inner tube. Each floor, or only the upper floors, may be provided with four rabble arms; and the material may be fed to the furnace from a hopper having a grooved roller. When the inner tube is made separately, it is centred by blocks and screws 8, Fig. 1, rests in a groove 7 at the bottom, and is held at the top by a cap 9. As an alternative, the two tubes may be cast together and the various sections connected by bolts &c. in the annular part of the spindle. At the bottom, the spindle is supported in a step bearing arranged above a removable block 23, and, when forced draught is employed, the lower part of the spindle is surrounded by a jacket receiving air from a fan. To pin the arms to the spindle, projections on the arms enter grooves 9, Fig. 3, and lugs 14, Fig. 4, at the top and bottom of the arms abut against corresponding projections on the exterior of the outer tube. A cap 40 is fixed at the end of each arm, and air is prevented from escaping into the furnace by an asbestos joint 12. In a modification, the end of the arm is of rectangular cross-section and tapered, and is shaped as shown in Fig. 12, so that, when rotated in the direction of the arrow, there is a tendency for the arm to be thrust into the sleeve of the spindle. A projection 34 is provided to prevent the arm from leaving the spindle upon reverse rotation, and abuts against a shoulder 35 on the inner tube. The partition 16 within each arm is held at the rear end as shown in Figs. 3 and 4, and at the front end is attached to a screw-threaded rod 18, Fig. 1, the nut 19 forming a plug. A second rib is provided when the arm is enlarged as shown at 20, and beneath the central aperture 1 in the floors, the arm is cast with slopes 2. The spindle is driven by a toothed wheel 24, Fig. 1, preferably detachable and engaging with a pinion 25, and means is provided for automatically stopping when the strain is excessive. For feeding the furnace, a hollow drum 30, having fairly flat recesses, is arranged within the hopper and driven by connexions with the driving-gear of the spindle. The material passes into the furnace along inclined planes 33. The Specification in the original form, as open to inspection under Section 91 (3) (a), also refers to the fact that, by the provision of the funnelshaped openings in the centre of the hearths and the inclined conduits at the circumference, the ascending gaseous current passes over but not through the pulverulent material ; this statement does not appear in the Complete Specification as accepted.