Stationary steam engines, simple and compound; especially as adapted to light and power plants . thence into the condenser or into the atmos-phere. The principles of the compound engine will be dis-cussed in the next chapter ; but a peculiarity of this typemay be best described here. The indicator diagram pro-duced by the engine is very nearly that shown in theaccompanying figure. By giving the intermediate chamberor receiver, which here becomes a clearance space for the ELECTRIC LIGHTING PLANTS. 175 small cylinder, a volume having the same proportion to thesmall cylinder that the volume of th
Stationary steam engines, simple and compound; especially as adapted to light and power plants . thence into the condenser or into the atmos-phere. The principles of the compound engine will be dis-cussed in the next chapter ; but a peculiarity of this typemay be best described here. The indicator diagram pro-duced by the engine is very nearly that shown in theaccompanying figure. By giving the intermediate chamberor receiver, which here becomes a clearance space for the ELECTRIC LIGHTING PLANTS. 175 small cylinder, a volume having the same proportion to thesmall cylinder that the volume of the latter bears to thelarge cylinder, with several ingenious and effective correc-tions for minor variations of kinematic and thermal move-ment, the single valve is made to give precisely the distribu-tion desired : such that the expansion in the small cylinderfrom any point, ^, and into the larger, up to the cut-off ofthe latter, will always give a terminal, at B, such that thecompression in the small cylinder will carry the line up toboiler pressure. The action of the low pressure compres-. ECONOMY UNDER VARYING LOADS. sion completes the diagram in singularly admirable form,and, incidentally, aids by reducing the liability to wastes byinternal condensation. The curious result is thus reachedthat the total range of temperatures and pressures and theirdivision between the two cylinders remain nearly constant,whatever the load on the engine ; and the machine is thus X76 STEAM ENGINES FOR caused to adapt itself comparatively perfectly to all loads,and to vary comparatively little in its efficiency, and thiswith a single valve and the simplest of mechanism. Thisresult is illustrated by the accompanying diagram, whichthe makers give as the result of their experience with thevariations of economy of the three classes of engine withvarying loads and correspondingly varying expansions, andby the following figures : WATER RATES, BY TEST, UNDER VARYING LOADS. Horse-Power. 210 170 ?40 5 1
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectsteamen, bookyear1902
