A Treatise On The Principles And Practice Of Dock Engineering

509 OHAPTER XII. WORKING EQUIPMENT OF DOCKS. Sources of Power—Compressed Air—Steam—Water under Pressure —Elec- tricity—Comparative Expenditure op Energy—Crane Tests—Cost of Power —Hydraulio Machinery—Systems of Electricai. Distribution—Applications to Dock Equipment—Gate Machinery—Power of Gate Machines—Sluicing Machinery—Capstans—Quay and Floating Cranes—Jiggers and Trans- porters— Coal Tips and Lifts— Grain Elevators — Slipway Haulage — Dumping Installations — Petroleum Storage —General Equipment — List of ApPLIANCES IN USE AT Hamburg, Havre, AND LIVERPOOL. The subject of dock equipment is scarcely less extensive, and certainly no less important, than that of dock construction, strictly so-called. Indeed,. the two departments are so intimately associated in aim and development,, that they cannot well be separated, and a technical work which prétends to any completeness of treatment, must inevitably include not only an outline of the nature and functions of the varions appliances included in the working equipment of a dock system, but also some description, however succinct, of their essential parts. Any elaborate investigation appertains, of course, more appropriately to the domain of the mechanical,. and, often in these later days, the electrical specialist; but, without some general knowledge of the subject, a dock engineer would be manifestly imperfectly fitted to discharge the duties and responsibilities of his position.. Before proceeding to a categorical analysis of the machinery in question, it will be well to devote a few preliminary remarks to the broad question of sources of power—their availability, utility, and economy, for the respective purposes held in view. Power.—The power employed for actuating dock machinery is derived from four sources :— 1. Compressed air. 2. Steam. 3. Water under pressure. 4. Electricity. Strictly speaking, all but the second of these agencies are mere trans- mitters of power already in existence. As a matter of fact, all present forms of power have their practical origin in the steam engine,* by which ’ The waterfall and windmill are ignored as too limited in application and as unlikely to be resorted to in connection with dockwork. Internai combustion engines, such as the gas engine, despite their great potentialities and rapidly inereasing use, have not yet acquired sufficient importance as prime movers to bring them into active compétition with the steam engine. The day, however, is not far distant when they will gain a very prominent position in this respect.