The Mechanical Handling and Storing of Material

HANDLING BLAST-FURNACE STOCK 353 the gantry correspond with the rail portion of the cradle, and the car is carried by its own weight down a slight incline to the furnace, emptying itself as it passes over the conically shaped mouth. As the loaded car automatically runs towards one of the furnaces, it raises a countei- weight, which, as soon as the car is discharged, draws it back to the lifts. The Lürmann principle has undoubtedly this advantage, that in case of a bieak- down of one of the two elevators, the other could be used to serve both furnaces.. A second advantage no doubt is this, that the rails of the cradle, when in its lowest position, correspond with the rails which lie parallel to the furnaces and run right under the store bins from which the car is to be filled. Furnace Hoists of the Brown Hoisting Machinery Co.-Fig. 493 shows an American furnace elevator erected by the Brown Hoisting Machinery Co. This hoist consists of an inclined iron-trussed bridge reaching from the floor of the stock house to the top of the furnace shell, and from thence over the top opening of the furnace. On this inclined bridge are laid the rails, on which travels a skip or car containing a charge of from 1 to 3 tons as may be desired. The track is so arranged at the top that the car automatically discharges itself. as already described. The hoisting is effected by a two-cylinder engine, with a friction clutch drum, installed at the foot of the incline, while the skip is lowered to the bottom for refilling by means of a powerful foot brake, without reversing the engine. Fig 494 shows a portion of the Carrie furnaces of the Carnegie Steel Co., with the conveying plant serving them. It was the work of the Brown Hoisting Machinery Co. The coal-tip on the right deals with the material which is received by rail. I he material discharged from the rail trucks into the bin is withdrawn into buckets holding about 10 tons each. These buckets are placed on the electric cars, each of which can hold four buckets. The buckets are then picked up by the Brown travelling crane, as shown in the illustration, and the ore is emptied into the stock piles or into the bins in front of the furnace From the bins the ore is drawn out through suitable openings into electric travelling trolleys, one of which is shown in Fig. 598, page 427. These are so made as to hold one charge of the elevator skip which takes the material to the top of the furnaces. The trucks are equipped with weighing machines, so that the exact quantity required can be taken at each trip. An elevator for loading coal on similar lines is described under the heading Coa Loaders at the Japanese Port Miike,” page 595. __ The same principle used to be applied to grain elevators, but the only example is probably that of the Liverpool Dock granaries (see page 670). Small hoists for the disposal of ashes from steamers, on the same principle, are also used sometimes. THE HANDLING OF ORE FROM SHIP OR STOCK PILES TO FURNACE HOISTS The Hoover & Mason Ore-Handling Plant.—This very interesting plant has been installed at the South Works of the Illinois Steel Co., U.S.A., and the makers, Messrs Hoover & Mason, Chicago, claim that it has solved problems which have con- fronted engineers for years past. They point not only to the quick discharge of the ore from the hold of a vessel, but also to its stocking in the blast-furnace yard, where it is always readily accessible; to its economical handling by means of the bin system, in connection with coke and limestone, and to its continuous delivery at the top o tie blast-furnace. 23