hand wheel. The motion of the grates is also regulated by a pair of lock nuts on the connecting rod projecting through the front, and by the adjustment of the hand wheel and the lock nuts the quantity of fuel and the motion of the grates are regulated. These two simple adjustments are within the comprehension of the most ordinary firemen, and their simplicity illustrates the leading characteristic of the stoker in its entire construction. The stoker can be applied to boilers already in place with very little disturbance of the setting, as the side walls are not disturbed, merely the lower part of the front removed and the grate bars with their supports introduced into the space previously occupied by the flat grate setting.

A much more extended application of this stoker in connection with coal and ash handling machinery was shown us by Mr. Atkinson in a number of views of what can be justly styled "A modern boiler plant" (see Figs. 2, 3, 4, 5). It was designed and constructed for Messrs. Curtis Davis & Co., Cambridgeport, Mass., by Westinghouse, Church, Kerr & Co., engineers, Boston. This plant when completed will consist of eight return tubular boilers, of one hundred and twenty-five nominal horse-power each, built to carry a working pressure of one hundred and thirty pounds per square inch. The boilers are equipped with the Roney mechanical stoker and smokeless furnace, coal and ash handling machinery, economizer and mechanical draft, all so arranged as to produce the maximum amount of power with the minimum consumption of fuel and labor.

The fuel used is Pocahontas coal, delivered by carts, which dump it onto the grating at the end of the boiler house. The fine coal passes through and the large lumps are easily broken by the teamster, thus bringing it to a uniform size. After passing the grating the coal is raised by a bucket elevator to thenveyer extending the entire length of the boiler house, andh distributes it in the bunkers supported on iron co front and above the boilers. From these bunk

flows by gravity through spouts to the stoker

matically supply it to the furnace as required. The ashes from each boiler are taken by a screw conveyer underneath the floor to another elevator, which delivers them into an overhead ash bin, from which they are discharged into carts for removal. Thus, from the time the coal is dumped by the teamster until the ashes are discharged into the carts there is practically no manual labor required to handle coal or ashes.

In addition to the saving in labor, so perfectly does the mechanical stoker supply the proper amount of fuel and oxygen that absolutoly no smoke is produced; not by burning it, but preventing it by perfect combustion of the gases which are usually allowed to escape up the chimney, a source of loss to the manufacturer and a nuisance to his neighbors. The perfect combustion of the fuel is also shown by the fact that the ashes from a ton of coal are but a little over one half those produced from the same quantity of coal under hand-fired boilers at the same manufactory.

The hot waste gases from the boilers pass through an economizer, thereby utilizing the heat they contain to heat the feed

water.

The necessary draft for the boilers is produced by a large, slow-running exhaust fan, discharging into a short iron stack placed immediately above it, and extending through the roof about twenty-five feet. The fan is driven by a small Westinghouse engine, having a pressure regulator attached to the steam pipe, for controlling the speed of engine and fan, so that they will run slow or fast, according as the steam pressure at the boiler varies. This fan, with its twenty-five-foot stack, is capable of producing a draft pressure equal to that of a two-hundredfoot chimney costing ten times as much to build, and is far more flexible in meeting sudden demands for steam.

The economy in labor and fuel obtainable from a plant of boilers thus equipped with stokers, economizers, coal and ash machinery and mechanical draft, will not only pay a handsome dividend on the investment, but will also greatly lengthen the life of the boilers, and reduce the possibility of accidents

due to the severe strains caused by the irregularity of handfiring.

We were also shown a sectional-perspective view of the immense boiler house and steam plant at the Spreckel Sugar Refinery, Philadelphia (see folder). This plant consists of eight thousand horse-power Babcock and Wilcox boilers, placed in two batteries of four thousand horse-power each, one above the other, with the coal-storage bunker occupying the third story of the building. This entire battery of boilers is equipped with sixty Roney mechanical stokers, to which the coal is supplied by chutes from the storage overhead as fast as required. The coal is delivered by train load to the boiler house, and dumped into hoppers which supply two large coal crushers placed underneath the railroad track. The coal when broken to a uniform size is delivered by means of spiral conveyers to vertical bucket elevators, which deliver the coal into a horizontal conveyer, which distributes the coal the entire length of the coal bunker above the boilers. The ashes are also discharged by gravity through chutes to a conveyer placed in the cellar, which in turn discharges them into an elevator, from which they are delivered into an elevated ash bin, from which they flow by gravity into cars for removal; so that from the time. the bottom of the coal cars are dumped there is no further handling of coal or ashes until they are delivered into cars for removal. So perfectly does the entire system work that one man with ease attends to two thousand horse-power boilers.

Mr. BARKER. Mr. HOWATSON raised one question, which was, why the Americans use the multitubular type of boiler, while the Englishmen use the Lancashire type. I know of no one who is so well fitted to answer that question as MOMAS J. BORDEN, and I should like to hear from him.

Mr. BORDEN. I suppose that Americans us tubular boilers extensively because the cost

and repairs, for equal steam capacity,

internally fired boilers of the English

ntal

tion

of

the

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When using bituminous coal there is an advantage in the passage of the flame the full length of the boiler before entering the return tubes, thereby promoting complete combustion with a minimum discharge of smoke from the stack. With horizontal tubular boilers properly set and fired, bituminous coal can be used with almost no smoke. There are some internally fired boilers at the sewage pumping station at South Boston, which yield good results as to economy of fuel, but their cost was much greater than an equal capacity of horizontal tubular boilers.

Mr. JOHNSTON. I will state why I adopted the multitubular boiler. Many years ago we put in some hog-nosed boilers; we ran them six years, not economically, and then, in rearranging our steam plant, we discarded these and put in boilers with the internal fire arrangement, and after running them for seven years we discarded those and put in the multitubular boiler. The hog-nose was a long thirty-two-foot tubular boiler, with the fire underneath, with a consumption of four, we will say; the internal fire boiler, six feet in diameter and eighteen feet long, we will say has a consumption of six; the multitubular boiler, with the fire underneath, has a consumption of ten, four, six and ten. What is the reason we do not get a better result from the internal fire boiler? The fire box is inside the boiler, and there are four inches of water space around the ash box. The air and feed of the boiler passing over the whole surface of the ash box, the water is chilled; and you lose all the gain there is from having a fire inside the boiler.

Mr. ATKINSON referred to one fact, that when we got the improvements made we would have slow combustion, and we would therefore have great economy; I mean complete combustion.

Mr. JOHNSTON. I made a test of slow combustion, ten years ago, with a one hundred horse-power tubular boiler, fire underneath. With slow combustion, lowering the draught, the evaporation was 6.5; I increased the draught and the consumption of fuel for the boiler forty per cent., and the evaporation was 10.5 instead of 6.5.

Mr. BIRKENHEAD. With soft coal how many feet from the furnace can you get a temperature of 212°?

Mr. HOWATSON. With our apparatus by which the smoke is prevented entirely, the gases going away from the fire at a higher temperature than the fire, we find back of the boiler a temperature of 2120. The heat is led round, the boiler on one side and brought back again, and is taken up by the shell of the boiler.

Mr. BIRKENHEAD. It would interest me, and I have no doubt the rest of the members, if some figures could be given as to the distance that heat will travel under or through a boiler from a furnace of anthracite coal compared with Cumberland coal, and also with a wood fire. I have noticed that hard coal, on account, perhaps, of its not carrying a flame, very soon loses its boiling temperature of 212°. If I am correct, is it not important that boilers should be constructed with this point in view, since in the case of a return-flue boiler the distance may be so great that the heat of the furnace may become in a measure absorbed before it has reached the chimney? If it should do so, would it not take away a portion of the heat it has just given?

Mr. BORDEN. The temperature directly under a horizontal tubular boiler, using either anthracite or bituminous coal, with boiler worked fairly up to its capacity, is rarely less than 700 to 800 degrees, and may be much more than 1,000 degrees. If carrying steam at 80 pounds' pressure, the temperature of which is about 324 degrees, exceedingly good results will be obtained if the temperature of the gases, after passing through the tubes, on discharge into the chimney, does not exceed 375 degrees. They are usually 400 to 500 degrees. Hence Mr. BIRKENHEAD's enquiry as to the effect of a temperature of less than 212 degrees is not pertinent. Heat once generated will travel under or through a boiler of a given type equal distan with equal diminution of temperature, whatever coal i The loss, by absorption of the foundations, or radi surfaces exposed to the air, is no greater with anthr