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P a MARINE REVIEW. NGileesVelels CLEVELAND, O., ann CHICAGO; ILL., PONE i ms63. No. 22. Condensers of a Large Cruiser. AS Be Wilts, 0. S. Ne In no more striking manner can be illustrated the great power developed by the machinery of a stedmship of the largest and swiftest class, than by a statement of the quantity of water which is, during each minute, converted into steam, used ex- pansively in the engines and again reduced to water in the con- densers, and returned thence to the boilers. The fact of this endless repetition of its function of porter of heat and equivalent work, may be of quite common knowledge, but the quantity thus used is seldom referred to in print and is astonishing to even many of those who are familiar with steamers and machinery; while to the non-professional, the condensing feature is probably more novel and surprising than that of the original evaporation in the boilers. It may be assumed that, broadly speaking, the modern marine engine will require about 1714 pounds of water per horse- power, per hour, and when a ship of the type of the new United States cruiser Columbia is considered, where the horse power approaches 21,000, a simple calculation shows that the total quan- tity of water thus demanded amounts to more than. 367,000 pounds per hour, or to put it more graphically, these engines will use, in the form of steam, about two and three-quarters tons of water each minute during which they are operating at full power. As it is most essential that there shall be practically no no waste of this steam, and that every pound of it shall be con- densed to its original form, after it has left the cylinders, the heat not converted into work therein, is sufficiently removed by the cooling surfaces of the condensers, hence mechanical provision .for the efficient performance of this latter operation is a most im- portant item in the general economy of the machinery, anda description of the apparatus designed for this punpese for the cruiser named is interesting. The engravings represent one of the three condensers of the Columbia. 'The material used in its construction is composition throughout, and its finished weight is about 27,000 pounds, or 12 tons. 'The length is 13 feet 8 inches. and the diameter of the shell is 6 feet 7 inches. The condensing water enters from the circulating pump at the nozzle A, and passing through the Jower half of the tubes to the other end, returns through the upper half and proceeds overboard by a pipe attached to the upper nozzle B. The steam from the exhaust pipes of the cylinders enters through the side nozzles C, and is scattered over the cool tubes, being by them condensed to water, and, falling to the bottom, it is drawn out by the air pumps, and eventually sent to the boilers. _ There is, of course, a great range of temperature of the con- densing water, both on account of the different seasons and by reason of the ship visiting tropical as well as arctic seas, and for this reason ample allowance of cooling surface must be given. In the case here illustrated, each condenser has 4,894 tubes of 12 feet length, and which, if placed end to end, will extend more than eleven miles. The cooling surface thus offered is 9,474 square feet. This aggregates for the three condensers more than thirty-three miles of tubes and about three-quarters of an acre of cooling surface. Another point of interest is the vast quantity of cooling water which must be sent through the tubes to pertorm the con- densing work. 'The estimates for this at average temperatures is about twenty-five times as much as the water to be condensed, and gives the enormous amount of seventy tons Der minute, a stream of no insignificant proportions. The importance of having a good and efficient condenser can not well be over-estimated. A good vacuum is essential to the production of the designed power, and many failures to reach this have been directly traceable to faulty design of this adjunct and its attached air pumps. 'The present proportions appear to give excellent results, but the field is open to the inventor for improving upon them and adding features calculated to increase ite durability or to afford greater facility for cleaning and over- @erboag 3 RB u ie if : i = 4 il! IE) i" [Ei amt lf I! j A {il F i Ml if hyve 'Fl " if, i, f ra) I ee ( ¥ ce | rT A SS Condensed Waler 3 vw ev Se Conta ne hauling. The tubes themselves frequently give way or are destroyed by a galvanic action sometimes difficult to discover the source of, and, indeed, the subject is full of points well worth the study of designers. In case an international conference should be held on the subject of a reform in the code of maritime signals, France will demand that a special meaning should attach to each letter of the code; also that two new flags should be added to the eighteen regulation ones, so as to raise the number of signal words from 30,000 to 120,000. TW Ea oe