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The next thing that we have to consider is the separation of the steam from the water. To do this effectively, there should be a large area of water-level, large steam room and a good dome. Every one who has designed boilers with cylindrical shells knows how impossible it is to get as much area of water-level, or as much steam-room, as he would like. By constructing our boilers with vertical sides, as shown in Fig. 1, the water-level will be the full size of the boiler, and the steam-room and steam-dome can be made of any size desired, and the steam would be effectually separated from the water.

The fifth point to be considered is the facilities for cleanliness and for the inspection and repairing of the boiler. These should be ample. One of the difficult and disagreeable duties of an engineer in charge of steam-boilers is to squeeze in through a manhole, made as small as possible, and then when he is in, it is next to impossible to move, much less to thoroughly inspect, repair and clean the boiler. When we think of a boiler that will carry three hundred and seventyfive pounds per square inch, we are confronted with the question, How is such a boiler to be constructed so as to permit of easy access for the above purpose? The manholes would be placed in the ends of the boiler, and made with a number of braces running the whole length of the boiler, and holding the manhole plates together. These braces would have collars on, so as to keep the plates from being drawn together when the nuts are screwed up. This would give us two openings into the boiler of any desired size, one at each end. The braces holding the manhole plates would be removed. This would not only allow the engineer to go in but would give him space and ventilation, so that he could stay in until the work which he went in to do was satisfactorily completed. The surfaces of the manhole plates would be ground. Another factor in this connection is that boilers that have no surface-condensers attached become scaly. The operation of scaling is at the best a partial, tedious, and difficult one, consequently the effectiveness of the boiler is continually being impaired to a greater degree. The general use of surface-condensers would entirely prevent this great nuisance.

Lastly, we have to consider the questions of weight, space occupied, cost, and durability. The weight and cost of this boiler per square foot of heating surface would be greater, but the weight and cost per horse-power would be less than at present. As the power of the boiler would be increased nearly one hundred per cent., we could afford to pay for best qualities of materials. The space occupied by the boiler and fuel per horse-power would only be about half what it is at present; for locomotives and marine boilers this is a matter of prime importance. The durability would not be any less than our present boilers, the furnaces particularly of locomotives would last much longer because of the absence of scale. When scale is present the plates are highly heated and soon become brittle.

Having already occupied more time than I intended, I will close by briefly stating some other points which should be carefully attended to, in order to secure the most economical results. The passages for steam should be large, short, and direct; the loss by radiation should be prevented by the most efficient jacketing; the valves and pistons must be tight; we must have quick-moving pistons and all moving parts thoroughly balanced; the percentage of engine friction must be reduced to as low a point as possible; all pumps should be run at a moderate speed, and by the main engine.

A frequent cause of loss is the failure to jacket the cylinder headsthe cylinder heads of most engines being polished bright and exposed to the air. They should be as well protected with jackets as any other parts with which the steam comes in contact.

For high-pressure steam the slide-valve will be found the most satisfactory, as it is constantly wearing itself tight. The locomotive engineers use the highest steam pressure, and they prefer slidevalves. They must be balanced, however, and there are several ways of doing this. Packing rings on the back of the valve are used largely by the Grand Trunk Railway, and the piston-balance is used by Worthington on his pumps.

The use of steam-packing for pistons will not answer for high pressures, the ordinary three-ring packing is preferable.

The beam-engine promises to again become popular on account of its being so well balanced and its low percentage of engine-friction, even for propellers, as in the case of the steamship “Louisiana," of the Cromwell Line, designed by Mr. John Baird.

All the pumps should be run by the main engine, because it is a very economical motor, and will do the work with greater economy than independent engines. The pumps should also be run at a moderate speed, because water is incompressible, and much power is lost by moving it quickly. Steam is one thing and water a very different thing, as all engineers know.

In conclusion, I beg to call attention to the loss of such a large percentage of the power of the fuel in the condensing water. Can we do anything to prevent this loss? We know how beautifully Siemens has succeeded, by means of the regenerative principle, in preventing the loss of heat escaping up the chimneys, in our iron and steel works, and returning it to the furnaces. Is it possible to take the heat out of the steam while condensing and return it to the furnace, and thus realize a very great economy of fuel ?

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Memnuny - I way yn 79 as best at tiis tine, Insa V, lunt, win the blo444 4 9 stem: sf stran st. Ezt B.14 I 1662 2,30 barn, , 13 st, deci téat scet or later ** 16.0*t, muut ad umbut616, 929 52 the other. It sees at irst Wibe nhi th1642.46 *toder strider the easiest of steam st 1r'an kiz W, un when the the time that at from tweety In Braty na etapie. Batzuk it la 1st a greater aitance tcan bine bu es sale, in the sout 15 years in arirancang from one or two ntatuirupokezi, 10 minut narraplus. In that ezee we have made nii wiektu by younal 434, and we are stepping along at the pres kuihtsink in the togalermount of high stean, but we do it so gradually That me mout, the problezna (16tusl with it in a like gradual manner.

I to making those iramutan stride we are brought face to face with mu porobolen hat uamn* very d.fruilt to uttle; but if it shall be demon#hrubad that very kupurius conomy reults from the employment of khawin at that presente, undoubtedly these difficulties may be, and will he met and vanquished, but in onr present knowledge of steamengineering, it would neem uuelesu to expect any very important wotnie rondte from the employment of steam at that pressure, becomes we must firut study the science of high-pressure steam-engineering That is undoubtedly the reason why those results in the fow instance with which we aro acquainted have not appeared.

In reference to the peculiar form of the boiler advocated in the paper round before 14, that would seem at first to be a step in the wrong direction. It would moem so, probably because it is contrary to our ordinary practice. That in, we are accustomed, especially in land or stationary boilers, to employ the circular section from choice, and a Ant noction from nocomnity, nm it were. But it is a question if this

am very thing ham not brought us to a point where we get a good conulruction for our circulnr hoction and a poor construction for our flat Hoolion. Now, if wo turn tho matter right over and begin at the other end, and work from the understanding that we have to do with this lint, noction, and thnt wo have to construct and stay it in a manner to resist thono pronkuron, it is a question if we should not do it so as to be botter ablo to rovint a pressure of even twenty-five or thirty atmospherom thun wo do nt the present time. We should from neceswity reduce the bracing of a boiler to a science—at least to a system whicli in more than we can say at present.

There seems nothing dilliould in the matter whatever. Then, again, we get, in our pronont construction, the habit of increasing enormously the diameter of our circular Noction, until we develop a certain weakness there which we uhould not develop in the flat construction.

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is no reservoir of heat stored in fire bricks, the temperature of the furnace will be lowered and much of the gases from the fresh coal will pass

off cold and unconsumed. On the other hand, if there is a damper very little cold air will enter when the door is opened, if the furnace is near the top of the boiler, the absorption of the heat by the water will proceed more moderately, and the reservoir of heat in the fire bricks will maintain the temperature of the furnace and ignite the gases from the fresh coal. These statements are based on the well-known fact that gases are burned much more perfectly when the oxygen and carbon are at a high temperature. The furnace being at the top and surrounded by water, at a comparatively high temperature, would assist materially, even when the door was shut, in maintaining the temperature at a higher point than it would if near the bottom of the boiler and surrounded by cold water. To this fact of the high temperature of furnace, and perfect combustion of gases, is to be attributed the comparatively good results obtained from the water-tube boilers and the cylindrical tubular boilers set in brick-work. While not approving of the building of our furnaces entirely of brick, as in the boilers last named, we should have enough fire brick in our bridge walls to act as a reservoir of heat for the proper heating of the gases, and a combustion-chamber where the gases can be thoroughly ignited before entering the tubes. (See Fig. 1.)

The third point to be considered is the absorption of the heat by the water. The main things in this connection are to have the gases escape from the boiler at a low temperature, and to have clean surfaces of the metal for the water to come in contact with. The gases should escape at the bottom of the boiler where the cold water is, and we should use surface-condensers for all engines. If the gases escape at the bottom of the boiler, they can be comparatively cold and still impart heat to the water; and if we use surface-condensers we will not be troubled with scale. It has been found that a scale one-sixteenth of an inch thick requires an expenditure of fifteen per cent. more fuel. As the scale thickens, the ratio increases ; at one-quarter inch thick it adds sixty per cent to the fuel required. Our locomotive engineers

“We cannot use surface-condensers ;” but there is no reason why the surface-condenser could not be carried on the tender instead of the great quantities of water that are now carried, and the water for condensation picked up and dropped as they go along. In cold weather it might even be possible to condense by means of the cold air-current, caused by the motion of the train. The saving of coal, which might be expected on our locomotives from the vacuum, the clean boilers and the greater degree of expansion, would be enormous, and is worth looking after.

will say,

The next thing that we have to consider is the separation of the steam from the water. To do this effectively, there should be a large area of water-level, large steam-room and a good dome. Every one who has designed boilers with cylindrical shells knows how impossible it is to get as much area of water-level, or as much steam-room, as he would like. By constructing our boilers with vertical sides, as shown in Fig. 1, the water-level will be the full size of the boiler, and the steam-room and steam-dome can be made of any

size desired, and the steam would be effectually separated from the water.

The fifth point to be considered is the facilities for cleanliness and for the inspection and repairing of the boiler. These should be ample. One of the difficult and disagreeable duties of an engineer in charge of steam-boilers is to squeeze in through a manhole, made as small as possible, and then when he is in, it is next to impossible to move, much less to thoroughly inspect, repair and clean the boiler. When we think of a boiler that will carry three hundred and seventyfive pounds per square inch, we are confronted with the question, How is such a boiler to be constructed so as to permit of easy access for the above purpose? The manholes would be placed in the ends of the boiler, and made with a number of braces running the whole length of the boiler, and holding the manhole plates together. These braces would have collars on, so as to keep the plates from being drawn together when the nuts are screwed up. This would give us two openings into the boiler of any desired size, one at each end. The braces holding the manhole plates would be removed. This would not only allow the engineer to go in but would give him space and ventilation, so that he could stay in until the work which he went in to do was satisfactorily completed. The surfaces of the manhole plates would be ground. Another factor in this connection is that boilers that have no surface-condensers attached become scaly. The operation of scaling is at the best a partial, tedious, and difficult one, consequently the effectiveness of the boiler is continually being impaired to a greater degree.. The general use of surface-condensers would entirely prevent this great nuisance.

Lastly, we have to consider the questions of weight, space occupied, cost, and durability. The weight and cost of this boiler per square foot of heating surface would be greater, but the weight and cost per horse-power would be less than at present. As the power of the boiler would be increased nearly one hundred per cent., we could afford to pay for best qualities of materials. The space occupied by the boiler and fuel per horse-power would only be about half what it is at present; for locomotives and marine boilers this is a matter of prime importance. The durability would not be any less than our present boilers, the furnaces particularly of locomotives would last

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