GB525245A - Improvements in or relating to underfeed stokers - Google Patents

Abstract

525,245. Screw conveyers. FITCH, H. H. Feb. 21, 1939, No. 5813. [Class 78 (i)] In an underfeed stoker fuel is delivered from a bin to a furnace by a screw conveyer co-operating with means below the furnace whereby the fuel is forced upwardly into the furnace. As shown, the fuel feeding conveyer is tapered and co-operates with a tapered screw conveyer of opposite hand in such a manner that the fuel is forced upwards into the furnace by the inner ends of the opposed screw threads. In one construction a shaft 47, Fig. 2, carrying screws 38, 48 of opposite hand extends below the intake 12 of a retort 11 into a fuel supply bin 18. The screw 38 passes through a conduit composed of telescopic members 39, 25 which can be adjusted with respect to the furnace and bin respectively. One end of the shaft 47 is formed as a polygonal socket 34 which receives a similarly shaped tongue 33 formed on a rotatable member 31 mounted in a support 28 on the floor or wall of the bin. The other end of the shaft is formed as a polygon 82 and is received in a coupling 83. The polygonal end 60 of a driving shaft 58 is received also by this coupling. The conduit 43 surrounding the part 48 of the screw is mounted telescopically in the lower part of the furnace and is bolted to a sleeve 70 secured to the gear casing. A plate 76 secured between the flanges of the sleeves carries a sealing structure 79 which supports an enlargement 80 of the shaft 47. A cone thrust-bearing 87 is placed between the plate 76 and a collar 85 which is secured to the coupling 83 and is seated in a recess 81 in the shaft. The tube 70 is filled with grease. In another construction the socketed end 244, Fig. 4, of the screw 243 is connected to one end of a tube 249 by a pin 247. The other end of the tube 249 receives a shaft 259 and is detachably connected thereto by a bolt 270. The socketed end 260 of the shaft 259 is slotted to receive a pin 254 on a driving shaft 252. The housing 253 is detachably secured to the gear casing 251 and is also secured to an arm 264 which is part of the motor base. A sleeve 266 is bolted to the housing 253 and receives the tube 241. A set screw 268 mounted in the sleeve serves as a stop for the end of the tube. On the other side of the furnace is arranged a tube 273, Fig. 5, for conveying the fuel from the bin. This tube is in axial alignment with the tube 241 and is supported in the opening 281 of the bin by a, pair of complementary members 285. A collar type bearing 282 is secured to the plate 277 and carries pivot screws 288 which engage aligned recesses 290 in the spherical surface of the members 285. In the construction shown in Fig. 8, the bin portion of the conveyer carries flights 343b terminating at 343b<SP>1</SP>, and the flights 343a of the furnace portion terminate at 343a<SP>1</SP>. Tubes 373, 376 containing these parts are connected by a sleeve 375. A spiral strip 301 carrying a flight 302 receives the shafts 386a, 386b and is secured thereto by set screws 308.