The Mechanical Handling and Storing of Material

6o2 THE MECHANICAL HANDLING OF MATERIAL the coal to run out on to the inclined conveyor. This conveyor, in moving forward towards the quay, draws the coal gently down the slope through the door, filling the conveyor with a layer of coal of a certain thickness, which travels to the edge of the quay. It is at this point received by another conveyor mounted on a jib, the outer end of which can by gearing be lowered or raised to suit the level of the ship to be loaded. The coal is carried on this second conveyor until it arrives at the end of the jib, the position of which is so adjusted as to plumb the hatchway. At the end of the jib are suspended a pair of vertical chains moving in a trunk; these chains have large trays upon each alternate pair of links, and these in turning round the top drum form them- selves into hoppers, the back of the advance tray and the front of the following tray forming a hopper. The coal from the end of the jib belt is directed into this naturally formed hopper. As the trays clear the top drum, they slide at an angle down the trunk, the coal being gently lowered until it reaches the level of the coal in the hold, where it discharges itself as the chain passes over the lower drum of the device. The speed of the different conveyors is as follows: The shore conveyor travels at 40 ft. per minute, the jib conveyor at 60 ft., and the hanging conveyor at 52 ft. per minute. The whole machine is self-contained upon a platform which can be moved backward and forward by the same power that drives the conveyors. In addition to this loading of the coal, some of the trimming is effected by the machine, as the jib is so arranged as to slew right and left over a space equivalent to the length of the hatchway. The vertical trunk, being upon the swivel joint at the end of the jib, can be deflected into a position which enables the coal to be delivered under the coamings of the hatchway, thus saving a portion of the cost of trimming, and the further breakage involved in that operation. The conveyors are all driven by an engine with a pair of 10-in. cylinders, the power expended being about 20 H.P. The man in charge can control the speed of the conveyors as well as the raising and lowering of the jib, and the racking in and out of the platform, by means of handles and clutches placed in a convenient position. As an alternative to the retarding conveyor, a large rectangular or circular box or trunk can be suspended from the jib to receive the coal from the second conveyor. A large valve is arranged at the bottom of this trunk, which, on being opened, allows the coal to flow into the hold of the vessel at the same speed as that at which the top is being filled from the conveyor, thus keeping the trunk always full. This valve can be controlled by a cataract or other form of brake, and so made that after the trunk is emptied the valve rises to the top ready to receive the next supply of coal. Coal Loaders at Grimsby.—In order to load coal into ships with a minimum of breakage, the appliances shown in diagram, Fig. 847, have been installed at Grimsby. This loader is similar to that in the Northumberland Dock on the Tyne (see above), but at Grimsby the coal is first unloaded from the trucks by a tip discharged at the level of the rails on to an inclined band conveyor, which delivers on to a Marcus conveyor b running parallel with the dock wall and capable of delivering at a number of points under the portable loader proper to suit the position of the ship’s hold. A steel plate conveyor c supported by a portable structure a delivers into the lowering device d. Although the coal is undoubtedly carefully handled by this device, considerable damage must be done to it by transferring it from the truck to the band, from this to the Marcus conveyor, and then again from this to the lowering device. There are two such installations with a capacity of 1,000 to 1,200 tons per hour each.