Engineering Wonders of the World
Volume I

32 ENGINEERING WONDERS OF THE WORLD. Fig. 4.—A YARROW WATER-TUBE BOILER, CAPABLE OF DEVELOPING 1,500 H.P. {Photo, Messrs. Yarroio and Company, Limited, London.) the back of each furnace is fitted a combustion chamber, d. Here takes place the combus- tion of the gases given off by the burning fuel. From the combustion chamber the heated gases pass through the tubes e, giving up heat to the surrounding water during their passage, and are then led through the smoke- box f to the funnel. The upper portion of the boiler is filled by the steam, which is drawn off to the engine by the main stop- valve H. The first water-tube boiler to receive exten- sive application was the Belleville, which was introduced into the French navy in 1879, and came into more or less gen- eral use for British warships tube Boiler. _ . . . about 1893. Its introduction for the latter did not escape criticism, with the result that in 1900 a committee was ap- pointed to investigate the matter thoroughly, and to decide upon the best type of boiler for naval purposes. After four years of careful research and study, the committee reported in favour of the water-tube boiler, and stated that two types—namely, the Yarrow and the Babcock and Wilcox— were the most suitable for use in battle- ships and cruisers. The Yarrow boiler is illustrated in Fig. 4. The cylindrical steam and water chamber at the top of the boiler is connected by two series of inclined tubes, giving the heating surface, to two lower water chambers. In the case of the Babcock and Wilcox boiler, illustrated in Figs. 5 and 6, the straight sloping water-tubes connect sinuous water- boxes, which are in turn connected to a cylin- drical upper chamber half filled with water, the remaining space being occupied by the steam. The firing arrangements are clearly shown in the illustrations. Other types of water-tube Fig. 5.—A BABCOCK AND WILCOX MARINE TYPE WATER-TUBE BOILER, AS INSTALLED IN II.M. NAVY. View with casing removed to show furnace f, water- tubes t, and main drum d. '{Photo, Messrs. Babcock and Wilcox, Limited.)