Patent GB-771409-A (GB)
Title: Improvements in or relating to apparatus for charging fluent particulate solid material into furnaces
IPC: F27B1/20
Filed: 1955-06-06
Abstract: 771,409. Endless conveyers. ERIE MINING CO. June 6,1955 [June 21, 1954], No. 16178/55. Class 78 (1). [Also in Groups XII and XXXVII] Apparatus for feeding ore pellets to an indurating shaft furnace having a rectangular mouth 46 comprises an endless main conveyer 7 fed by a supply conveyer 31 from a balling drum 32, and an endless feeder conveyer 16 arranged transversely of the main conveyer 7 and having a discharge end disposed over the furnace mouth 46, conveyers 7 and 16 being so arranged and driven as to maintain a substantially constant rate of delivery of pellets, whereby a combination of longitudinal and transverse rectilinear movements of the discharge point of the conveyer 16 over the furnace mouth deposits a substantially uniform layer of pellets over the stockline. The conveyer 7 is mounted on a carriage 17 which is reciprocated on rails 25 running alongside the length of the furnace mouth, and the conveyer 16 is mounted on a carriage 18 running on rails 34 arranged on the carriage 17 at right angles to the rails 25. A motor 1 drives the conveyer 7 through a planetary-type variable speed drive 4 and chain and sprocket gearing 8 and 8<SP>1</SP>, and also drives the conveyer 16 through a speed reducer 12 and chain and sprocket gearing 14 and 15. A reversible motor 19 drives the carriage 17 through a speed reducer 22 and chain and sprocket gearing 23, and superimposes this drive on that from the motor 1 by rotating the planetary housing 5 of the variable speed drive 4 through a speed reducer 26 and chain and sprocket gearing 27. This latter arrangement ensures that the conveyer 7 moves past the supply conveyer 31 at a constant rate irrespective of the " east-west " reciprocations of the carriage 17. A reversible motor 35 reciprocates the carriage 18 through a speed reducer 36, chain and sprocket gearing 37, and a pinion 38 meshing with a rack 39. The chain and sprocket gearing 15 is arranged to compensate for longitudinal movement of the conveyer 16 by the arrangement shown in Fig. 5, in which a driver sprocket 40 and idler sprockets 41 and 42 are mounted on the carriage 17, and a driver sprocket 43 transmitting power from the chain 15 to the conveyer 16 is mounted on a drive shaft 44, which, along with another idler sprocket 45 is mounted on the carriage 18. As the latter is moved, the lengths of the sections X and Y of the driving chain 15 vary oppositely with one another. By the aforesaid arrangement of driving, driven and idler sprockets, the effective speed of loading of the conveyer is substantially constant whatever the direction and speed of movement of the carriage 18. A typical pattern of pellet deposit is shown diagrammatically in Fig. 9 in which ELS and WLS are limit switches located on the carriage 17 and operated as the carriage reaches the " east " and " west " end of its travel respectively, and in which NLS and SLS are limit switches on the carriage 17 but operated as the carriage 18 reaches the opposite ends of its travel. Each limit switch functions, when closed, to energize a control relay, Figs. 10 and 11 (not shown), in a circuit producing in turn an " east," " south," " west " and " north " movement of the discharge end of the conveyer 16 over the furnace mouth, by corresponding movements of the carriages 17 and 18. By this means also, while one carriage is moved longitudinally, the other is stationary. Since one conveyer always moves in a particular longitudinal direction with respect to its carriage, the carriage must move at a higher speed when its direction is opposite to that of the conveyer in order that approximately the same quantity of pellets may be deposited on each traverse. This may be achieved through the use of different resistances in the two armature circuits of each of the reversible motors 19 and 35. As disclosed in Specification 725,204, [Group XII], the rate of feed of pellets may be modified as a result of the existence of high and low spots in the stockline level. A feeler element riding over the stockline surface has a rod attached thereto, carrying contacts sliding over variable resistances connected in series with the field windings of the motors 19 and 35, Fig. 11 (not shown), so that the rate of travel of the feeder is automatically slowed over a low spot and speeded up over a high spot.