The Mechanical Handling and Storing of Material

LOADING COAL LNTO SHLPS OTHERWISE THAN BY TLPS 609 of the track (so as not to interfere with the shoot openings), and pushed along the dumping track, over the automatic lifter j, which secures the trap door of the truck when it is passed along to form a train of empties. In the meantime the transfer carriage has been drawn back by the piston rod c3 (attached to it and forcing it in both directions) till it registers with the supply track. The grip dog draws the train of loaded trucks one truck length towards the end, and then forces a loaded truck on to the carriage, which transfers it to the dumping track as before described, the whole operation only occupying about twenty-five to thirty seconds per truck. The four levers work on specially constructed valves, and efficiently control the pressure, c1 is an opening in c for dumping into the highest discharge shoot; c3, piston rod attached to the carriage, moving it in both directions; c4, lever controlling pressure in d to piston rod which forces the truck off carriage on to dumping track b ; e, catch locking truck on carriage until it registers with track b ; F, grip dog for moving trucks singly or the whole train of loaded trucks along the supply track a : F1, cylinder to operate grip dog F by piston rod F2, controlled by lever F4 : G G, grip dogs for moving trucks on dumping track B in a pair to avoid openings in the platform being openings into chutes : G1 G1, pair of cylinders to operate grip dogs gg by piston G2; 1, 2, 3, 4, openings in platform for dumping into shoots for different levels of water; j, auto- matic lifter for trap door of truck, after dumping contents; k, stationary boiler, if required. Figs. 853 and 854 show a plan and elevation along the dumping. track b, and Fig. 855 an application of the apparatus to loading a collier. The quantity of coal that could be thus dumped into a vessel can be placed at an average of 550 tons an hour for each loading shoot, and two shoots could be worked simultaneously at suit- able distances apart to suit the hatches of the vessel. As many as 750 tons per hour have been loaded by one shoot. The cost of loading say 5,500 tons of coal with a “Wall” apparatus is but 46s. The plant may be driven by hydraulic power, steam, or compressed air. It is said that fifty years ago the time taken to load a 1,000-ton vessel in this locality was between three and four weeks. This is not surprising when it is remembered that ships used to be loaded in those days by Indian women, who took out baskets of coal in their frail canoes which they handed up over the side of the vessel as she rode at anchor in the middle of the harbour. A similar system, but much simpler, is in use at the Tyne Docks, near South Shields, and it is thus described in a paper read by Mr J. D. Twinberrow before the Institute of Mechanical Engineers :— “Durham and Northumberland coals are transported in self-discharging railway trucks, the shipment being effected from timber staiths which contain hoppers fitted with spouts, projecting laterally over the vessels lying alongside. Tyne Dock, near South Shields, in Durham county, holds the record for the monthly and yearly tonnage placed on board. The arrangement is entirely self-acting, the wagons being run down the central roads by gravitation. In passing the short length of sharp inclination they acquire sufficient impetus to travel through trailing points on the rising grade, by which they are 39