. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . up to the boiling point, and,second, for the units of heat required toconvert each pound of the water intosteam at the same temperature. For ordinary rough calculations theamount of water actually evaporated bythe boiler during test is reduced to theequivalent evaporation from and at212° F. in the following way: For each June, 1906. RAILWAY ANU LOCOMOTIVE ENGINEERING 245 pound of water raised from the feed teni- water varies greatly according to the wlicre I has been shown for Ipcratnre
. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . up to the boiling point, and,second, for the units of heat required toconvert each pound of the water intosteam at the same temperature. For ordinary rough calculations theamount of water actually evaporated bythe boiler during test is reduced to theequivalent evaporation from and at212° F. in the following way: For each June, 1906. RAILWAY ANU LOCOMOTIVE ENGINEERING 245 pound of water raised from the feed teni- water varies greatly according to the wlicre I has been shown for Ipcratnre at 100 F. to the boiling point type of boiler and the proportion of grate sq. ft. These records, however, mustfor steam at 70 lbs. pressure which is area, but generally speaking, the Lan- be considered largely fictitious, as the316° F., we have to allow one unit of cashire type, where the ratio of heat- horse power shown by the indicatorheat for each degree 316 — 100 = 216 ing surface to grate area may be from diagram taken when running down hill can be made very high and be very PUSHER ENGINE AND TUNNEI, IN THE ROCKY MOUNTAINS. CAN. PAC. RY. units. Then we have to add 893 unitsof heat required to convert each poundof water at 316° F. into steam, whichis the latent heat of steam at 70 pressure, thus making the total216 + 893 = 1,109 units of heat absorbedper lb. of water. Now it takes about966 units of heat to convert one poundof water, from water at 212° F. intosteam at 212° F. at atmospheric pres-sure. So that it takes 1,109 ^ 966 = as much heat to raise water from100° F to st€am at 70 lbs., as it does toconvert water at 212° F. into steam at212° F., and if we apply this rale to thestandard mentioned above, that is, 30 water per horse power, we X 30 = 34-44, or about 34i/< horse power from and at 212°. If we take as an average the evapora-tion due to the burning of i lb. of coal as7^ lbs. of water, we
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1901
