The Mechanical Handling and Storing of Material

632 THE MECHANICAL HANDLING OF MATERIAL to which they may cause fire in the ash bunkers, or even explosions, if these receptacles are closed and thus prevent the escape of gases. Wet ashes damage mechanical conveyors and will not deliver readily, whilst pneumatic installations will not handle them at all, and finally in cold climates the wet ashes will freeze together in the bunkers, making their discharge into trucks impossible, unless the bunkers are fitted with heating apparatus. There is, however, no apparent reason why the ashes should be either too hot or too wet to be handled in suitable conveyors in well-managed establishments. If for some reason or other the ashes should be too hot or sopping wet, they can be handled intermittently by skips or mono-rails, or by the car and skip system which is advocated by the R. H. Beaumont Co., of Philadelphia. This consists of a hopper on rails pushed either by hand or electricity, which collects the ashes from hoppers under the boilers, and an electric skip car to raise and discharge them into overhead bunkers. Of course the Fig. 883. Cross Section through Coal-handling Plant at the Juniata Works, Altona, Pittsburg. system will answer equally well for all ashes in all conditions. If the local conditions are favourable the ashes may be collected in a hopper under each boiler and at intervals discharged into railway trucks which pass beneath. Ash bunkers are generally square or cylindrical with a hoppered base, and if closed they should be ventilated, if there is a possibility of the ashes arriving hot, in order to guard against explosions. The Use of Telphers in Gasworks and Power Stations.—Telphers fitted with a grab or clam-shell bucket are frequently used when handling coal, and with special tipping receptacles when handling coke. If the material to be handled is coal, it can be elevated from the cars, pits, stock heaps or barges, and with rehandling or retransferring, can be transported to the storage yard, to elevated hoppers, to the boiler room or to the furnace door. The coal can be raised and carried from the storage yards by the same clam-shell buckets to the boiler room. Electricity, through the telpher, hoist and bucket, does all the work, one telpherman the directing.