The Mechanical Handling and Storing of Material

CHAPTER XXI THE MECHANICAL DISPOSAL OF ASHES FROM STEAMERS The tendency to utilise mechanical means for handling material has become more and more,general, and important new fields for their operation have, within recent years, been opened up in the mechanical disposal of ashes and clinkers from the stokeholds of steamers. Development of Ash Ejection.—In the days of marine engines of small horse power, and consequent small coal consumption, the refuse of the stokehold was easily dealt with by hand labour, being brought up in buckets and emptied over the side. When the coal consumption had somewhat advanced, simple ash hoists were introduced, still utilising the bucket, and the general procedure remaining much the same, except that mechanical means were employed to raise the buckets to the deck level, or a few yards above it. The ashes or clinkers—in other words, the refuse from the boilers of large steamers—accumulate so fast that they have to be removed about every four hours from the furnace. After being cooled with water, they are generally filled into large iron tubs on wheels, which sometimes run on rails to a suitable position, whence they can be raised to the deck, and the ashes tipped overboard at intervals. The older methods employed ordinary hoists, by means of which the tubs were either raised through a special duct or a shaft, or more often one of the ventilating shafts was used for their passage. On the deck corresponding rails were provided, upon which the tubs were lowered and pushed to the side of the ship, and emptied into hopper shoots leading overboard. The Ash Hoist.1—All ash hoists have certain drawbacks or restrictions; they cause the intolerable nuisance of ashes being blown all over the deck of the vessel, to the annoyance and discomfort of passengers and crew. This is especially the case with passenger vessels in hot climates, owing to the ashes being blown into the cabins through the open portholes; if their operation is restricted to night time, the noise produced by them is almost equally objectionable. Ash hoists are also restricted to steamers working without forced draught, on account of the communication which the pipe affords between the stokehold and the open; worst of all, they are too slow and altogether inadequate for large steamers. With modern equipments of more powerful engines, and, consequently, much larger coal consumption, the disposal of ashes called for a more effective method; this led to the introduction of the hydro- ejector, which, as the name implies, ejects the ashes by hydraulic force, or, rather, by jets of water under pressure, outside the ship’s side, above the water line. This system answers very well, and is largely used in merchant steamers, in spite of sundry drawbacks; but in the case of battleships it was soon decided that the piercing of the armour to provide outlets for the ash tubes was undesirable on account of weakening the armour. Hydro-Ejectors.—Hydro-ejectors were first introduced by Horace See, of New 1 Ash hoists are fully described in an article by the author in Cassier $ Magazine of August 1912. 229