The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

TAE MARINE. REVIEW 3 23 superheaters and stokezs. Plate I shows a sectional, and Plate II a front view of one of the boilers. The superheater, it will be observed, consists of an upper and lower cross box having a number of bent tubes expanded into them. Steam, after being generated, is led BABCOCK & WILCOX BOILERS ON THE STEAMER JAMES C. WALLACE. PLATE: I. from the drum by an outside pipe to the forward end of the superheate-. After passing through the latter, it is directed through another outside pipe, at the after end, to the main steam pipe. One partition is placed in each cross box, thus causing the steam to flow three times from one box to the other in its passage from inlet to outlet. Suitable valves are installed in the piping, so that the generated steam may be sent either through the super- "heater, or, if desired, directly to the main steam line. Length of boile> proper. 345. ens ek tr ft, Ttigindiag: projection ot, stoker..4.....43 4. 14 fk. With Ol DOMEY ons oc bee Ea tt. (2) in, Petent Of borer to top of dram. 040... Ts tt Supereater <6 eo ee a $e 1t../8 am. Diamieters.O8 Mew: oo a3 eda i es 42: ip Leneth Over. heads cc. ee eee io it 6 an. A DICKHESS Of SEI OIAteS 005 hoe eae 19-32 in. Diameter Of BOVer tubes. oo oe. cs 4 in. Thickness: of "boiler tubes: 0 ae. 6B, W.&G. Length of tubes between headers......... ro. ft. Number of sections wide, each boiler...... 18 TRGMIGING « Sinle SectiONs, -. 0.) ee es 20 Diameter of superheater tubes............ 2 in. Thickness of Superheater tubes. . 2.5.2 5% ¢. 10 Bo W.-G. Square feet of grate surface, each boiler... 74 Square feet heating surface, each boiler.... 2,900 Square feet superheating surface, each boiler 414 matte Gr (5. tO le Oe T tO 39.10 Paclugme superhcater. 00 i I to 44.78 Each boiler is provided with two chain stokers of the Crowe pattern, all driven by a single-cylinder en- gine 6% in. by 6 in, (installed in the engine room and run at constant speed) through shafting, sprocket wheels, chain, eccentrics, etc. The speed of each stoker grate is independently controlled by an adjustable ratchet de- vice, and its rate of travel is regulated, as frequently as sss} { fleet (thot toe fit > tie | ; ; t Sc le 8 ¢v ernie ue == WE cizcumstances require, in order to maintain steam at the proper pressure. Coal is fed into hoppers, at the front of the boilers, the thickness. of the fire being governed by an adjustable plate extending across the width of the grate. The speed of the grate should be such that the coal, in passing from front to back, is entirely consumed. Ashes and clinkers are dumped and removed at the back of the boilers. It may not be out of place to note here that the stokers worked perfectly during the entire trip, and so easily was the regulation of. the coal supplied the furnaces controlled, that fluctuations in steam pressure were but slight indeed. No smoke issued from the smoke pipe at any time. Where, as is the case on the Wallace, the steam sup- ply demandéd, and, consequently, the speed developed, is fixed, and only changeable within narrow limits, there can be no question as to the decided superiority of stokers SS --S PLATE II. BABCOCK & WILCOX BOILERS ON THE STEAMER JAMES C. WALLACE. over hand firing from every standpoint. Moreover, prac- tical experience with stokers fitted to boilers of lake steamers during the past few years has resulted in im- proving the mechanical construction to such an extent that breakdowns are rare, and when they do occur, are usually readily and quickly remedied. In view of this success, the advisability of equipping at least one-half the boiler plant of men-of-war with stokers is worthy of serious consideration; flexibility could be provided for by hand firing on the remaining boilers. Three samples have been examined, and the heat value in British thermal units (by Mahler bomb calorimeter) per pound of dry coal, and proximate analyses are recorded below: PERCENTAGES OF DRY COAL. Volatile Fixed Bel. U. Matter. Carbon. Ash, Sawiple Noo to. 7.507 13,466 29.23 59.53 11.23 Sample No: 2.75.45 13,499 28.37 57.51 14.42 Sample No. 45.770. . 13,593 28.60 60.63 1077 ANVGIAGS iri eel aa 13,519 28.73 59.22 12.14 The coal used during the entire trip was westesn Penn- sylvania bituminous slack, loaded at Ashtabula. On each