The Mechanical Handling and Storing of Material

358 THE MECHANICAL HANDLING OF MATERIAL tram-car devices. The ore pockets were constructed of steel throughout, and designed to prevent the formation of arches in the ore mass feed. The sectional view, Fig. 500, shows how this and consequent interruption in the is accomplished by louvres. These louvres also afford access to the Figs. 499 and 500. Showing Hoover & Mason’s Ore and Coke Pockets and Scale Car. pockets in the case of a few very sticky ores, which, despite the louvres, have a tendency to choke. The withdrawing of ore from the pockets is effected by a rotating cylinder 5 ft. in dia- meter. The aperture for the exit of the ore is in all cases equal to the width of the pocket, so that the ends of the pocket are vertical. When it is desired to withdraw ore, these rollers are set in motion, forming a feeding device which carries the ore out of the pocket, and to a consider- able extent loosens up the mass within the pocket. These rollers are actuated by a motor-driven continuous running shaft, which can be geared to them by a fric- tion clutch. The rollers on the coke side are perforated, and efficiently act as screens in separating the dust from the coke (see Fig. 500). A hot-air chamber is placed under the ore bins in order to prevent their contents from freez- ing in cold weather. One weighing truck only is needed for each furnace. In the course of a year one man has kept a large furnace full without difficulty. Each weigh- ing truck has two compartments, each holding a skipful (see Fig. 500). All material delivered to the furnace is weighed before entering the skip. The weigh- ing truck is driven by electricity. The weight of each increment is recorded upon a strip of paper by the balancing of the beam, and is thus placed beyond the reach of any tampering, an unimpeachable record being kept of the total weight of material fed into the furnace. The coke is distributed along a considerable length, and not, as is often the case, into two large ore bins, delivering directly into the skip. The advantages of this plan are, firstly, that it enables