The Mechanical Handling and Storing of Material

47§ THE MECHANICAL HANDLING OF MATERIAL as the one just described and is successfully employed for the purpose of conveying coal. It has this advantage, that it is really self-trimming, and empties itself completely. It creates but little dust, and the coal is weighed automatically before delivery into the bunkers of the vessel. Fig. 661 represents a longitudinal section through the barge, a a a are the compart- ments in which the coal is deposited. Each compartment is fitted at- the bottom with three slides, which are opened and closed by hydraulic machinery illustrated in Fig. 662. Below the row of slides is a tunnel in which a gravity bucket conveyor is fixed, which is driven by a small engine and boiler at the stern of the vessel. The contents of the different compartments are in rotation deposited on the conveyor and moved in the direction of the arrow. On reaching the stern, the conveyor ascends, and the buckets are emptied in their highest position into the automatic weighing machines w w, from which the coal slides down the shoots ss into the bunkers of the steamer to be loaded (see Fig. 663). The shoots s s can be raised or lowered by winches. Fig. 664 represents a cross section through this self-trimmer showing the hydraulic machinery for raising the floor of the compartments a after they have partially emptied themselves, for the purpose of automatically completing the discharge. Coal can be unloaded from this barge at the rate of 100 tons per hour. Two such self-trimmers are used, one at either side of the vessel. Self-Trimming Barge of the Pittsburg Coal Co., Cleveland, Ohio, U.S.A.—T his barge was built by the C. O. Bartlett & Snow Co., and the illustration, Fig. 665, shows a longitudinal section through the barge, giving a general view of this self-trimmer, and showing the construction, which is as follows :— The barge is about 165 ft. long by 25 ft. beam, and is large enough to carry 750 tons of coal in addition to her machinery. The main body of the barge is divided into a series of hoppers, each 10 ft. wide, which extend nearly the entire length of the hull. The hoppers a are arranged in two rows, one on each side, leaving the tunnel in the centre, which extends from end to end through the barge. Each of the sixteen hoppers communicates with the tunnel by an outlet b, which is 3 ft. square. From this the coal can be deposited on conveyor e, running through the tunnel. The conveyor consists of two strands of a very heavy chain, to which are connected plates, which form, with the chain, a type of push-plate conveyor. The coal is allowed to pass from one of the hoppers a to the conveyor, and is then removed to the terminus, which is raised slightly above the level of the rest of the conveyor. The load is then delivered to the elevator e, which is built in a stout sheet-iron frame with ample supports for the guides of the buckets. It is manipulated by two strands of chain, in the centre of which the buckets are hung for the purpose of giving a perfect delivery, as shown in the illustration. The coal is discharged into hopper h, which is mounted on a turntable. Immediately beneath the hopper is the well of an inclined elevator, the delivery end of which is so arranged that it can be raised or lowered, and so convey the coal into vessels, which are to be supplied with bunker coal, at any angle from the horizontal up to 45°. To the delivery end of this elevator is attached a telescopic shoot which can be swung round to accommodate itself to the hatch of the boats to be coaled. The whole apparatus, including hopper H, is mounted on a turntable, which gives every facility for directing the delivery shoot into any position. The motive power for this inclined elevator is provided by a separate steam engine c, which is mounted on the top of the turn- table. It will be seen that the delivery of the coal can be effected on either side of this coaling barge. There is also a second engine D, which is placed on the deck of the barge