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MARINE REVIEW. W New Bridge Wall for Boilers. Boiler capacity is the next problem that must be solved before any great advance can be made in marine engineering. It is quite certain that advancement in making steam has not kept pace with improvements for using it. Whether this is because the designer and mechanical engineer thinks his work on boilers would not be appreciated so much as it is on the engine, which writes recommendations or criticisms of new de- signs and theories on indicator cards, it is difficult to say, but the engine is now in a position to ask to be let alone and have some of the attention that has been showered on it given to the boiler. Several lake steamers have been fitted with forced draft where speed is desired, but in cargo carriers fuel economy is more valuab'e than speed. It is stated by the tormer owners of the steamer A. P. Wright, recently purchased by J. C. Gilchrist, that by means of a new patent bridge wall she saves 25 tons of coal per trip, and in addition to this saving the boilers steam » Following are references to illustrations:-- Figure 1 isa vertical section of the hollow Bridge Wall, showing the damper connections. Figure 2 is a plan of the top. Figure 3 is a front elevation of the bridge wall in the fur- nace. Figure 4 is the back elevation of the same. Figure 5 is the section of a boiler, showing the furnace all fitted and under fire, and the manner in which the air passes up through the slots or openings in the top of the bridge walland meets the flame and gas as they are passing into the com- bustion chamber, thereby converting the gas into flame, increasing the evaporation and reducing the amount of fuel necessary to do the same amount of work. Letter a, figure 1, is the top, which can be removed from the bot- tom by taking out thebolt shownat the back. Letter b is the bottom of the bridge wall, which is held in position in the furnace by the studs g andh, figure 4,the wall slip- ping down over them. The studs h go into a slot and are to prevent thewall from being shoved over, while the studs TT WATT FIG. 2 Iran finn tn ron OT rng Mi an Cita Ma nr ! Wo wT pet TT Le Ponrt | inet ete uae bi {yuais( | aang Ut PPM LOOT when it comes in contact with the newly produced gas, the latter is not only almost entirely lost by escaping unused through the stack, but it cools the gases already in the combustion chamber, and in this way checks the generation of steam. The object sought and attained by the Tucker bridge wall is, to admit the necessary amount of air to produce combustion and to regulate it by a damper, which is worked from the out- side, and to so heat the in its passage to the combustion chamber that it will at once combine or mingle with the gases already in the chamber without cooling them, and thereby pro- duce more rapid and perfect combustion, which it not only does, but it also greatly lessens the smoke and the escape of soot and cinder from the stack as well as the deposit in the tubes, all of which proceed from the same cause viz., im- perfect combustion, and are largely due to the defective character and construction of the old style of bridge wall. For the bridge wall itself, aside from the advantages re- sulting from its use, there is economy because it is more durable, and being sectional, the upper part, which is above the level of the grate bars and more liable to burn can be easily removed g go through the casting and have uuts on the inside which hold the wall firmly in positnion, All studs are tapped through the sheet with nutand washer inside, By removing the two inside nuts from studs g, the wall can be lifted out of the furuace independent of the water space. Letter c is the Tompkin plate, which shoves in and covers the opening in the bottom of the wall b When any dirt is seen through thedamper d, pull the Tompkin plate out and it all fallsinto the ash pan,so thatthe wall is always clear. Letter d is the sliding damper,operated from the front of the furnace by the rode,so that the amount of air necessary can be regu- lated at any and alltimes. This damper restsona bevel strip at the bottom, so that there is no possibility ofstick- ing. Letter f is a section of grate bar resting on bear- ing bar which is cast on to the bottom of the bridge wall b. Letteri are the openings on the top a. Letter i,fionre 4, is a hand-hole plate, but is never used when there is room for a Tompkin plate. TT eT TE i sat juan inna pavane sn (Rr UI | PAC A LOTT Mo purancay | pasunzediparensee a | y UL PLL Coe CO o better, the perfect combustion doing away with the black smoke that usually comes from the stack. A saving of fuel of from 4 to 18 per cent. is maintained for the Tucker bridge wall by tes- timonials, the saving varying with the kind of coal used and other conditions, and besides there are additional advantages among which is the fact that boilers which are sluggish and hard to steam with the old style of bridge wall, are made to steam much easier with this. The following facts are indisputable: Coal must be distilled or converted into gas before it can generate the full amount of heat it is capable of producing. Whenever a furnace door is opened and fresh coal thrown on a fire, a large amount of gas is immediately produced which is virtually lost, so far as its heating properties are concerned, unless the oxygen or air, which must be admitted to unite with the carbon and hydrogen in the fuel to produce combustion, is heated before it comes in contact with the newly generated gas and before it passes into the combustion chamber. Unless the oxygen or air is heated and renewed. It also requires much less expense to keep it in order. This bridge wall is in use in over seventy steamers and several stationary plants on the Pacific coast and on six steam- ers running into New York, besides being in use on two lake steamers. John D. Spreckels & Bros., who have them in use on the eight steamers and tugs of the Oceanic Steamship Com- pany, say: "We are using Tucker's bridge wall on all our steamers and find they effect a saving in coal and to be benefi- cial to the boilers. Our tug boats now raise without difficulty all the steam required without the use of a steam jet in the smoke stack." Superintending Engineer Cosgrove of the Pacti- fic Coast Steamship Company says that company is using the Tucker bridge wall on ten steamers and in addition to saving coal he claims that they do away with dirt and soot that for- erly accumulated on deck. The Risdon Iron and Locomotive Works, San Francisco uses them for stationary boilers and rec- ommends them. 'The patentee is Mr. E. W. Tucker,and patents were granted May 17 and July 26, 1887, the same having been sustained by United States courts. HG, Trout:& Co., 224 Ohio street, Buffalo, N. Y., are lake agents for this bridge wall.