The Artizan . ty of this plan, and demonstrate the possibility of directing aship by the agency of a needle much less powerful than that of an or-dinary compass. CORRESPONDENCE. We cannot hold ourselves responsible for the opinions of our Correspondents. LAKES DIFFERENTIAL STEAM the Editor of The ,—In the differential steam engine, of which the annexed diagram exhibitsa vertical section, great simplicity of construction is achieved, in addition toincreased economy in consumption of steam. The engine comprises two cylin-ders of different diameter, so arranged as to be axial
The Artizan . ty of this plan, and demonstrate the possibility of directing aship by the agency of a needle much less powerful than that of an or-dinary compass. CORRESPONDENCE. We cannot hold ourselves responsible for the opinions of our Correspondents. LAKES DIFFERENTIAL STEAM the Editor of The ,—In the differential steam engine, of which the annexed diagram exhibitsa vertical section, great simplicity of construction is achieved, in addition toincreased economy in consumption of steam. The engine comprises two cylin-ders of different diameter, so arranged as to be axially in the same straightline; these cylinders are furnished with pistons, as shown in the sketch, that inthe small cylinder being perforated round its periphery between the packingrinss. The interior of the piston communicates with a trunk or chamber, whichconnects it to the large piston in the expansion cylinder, which is open at thebottom. When the small piston is at the bottom of the stroke, as illustrated. the holes in its periphery correspond to others in the curved lateral steam pas-sages, of which the other ends open into the cylinder a little higher up, andthrough which steam from above the small piston flows, filling the trunk andspace below the large or expansion piston. Let as now examine the effect of the working of the engine, assuming thefollowing dimensions : Diameter of small cylinder, 8in.; of large cylinder, 16in.;stroke, lft. : cubic contents of trunk equal those of the small cylinder; pressureOf steam above the atmosphere, COlbs. per square inch, or absolute pressure7lh-. per square inch. The effective area of the small piston may he taken as BO square inches ; thatOf the large piston being four times as much, or 200 square inches. First we(rill consider the work done in the down stroke through which the steam actson the small piston with its full force: we have 60 sq. in. x 751bs. per sq. in. xlft. = 3,750ft. His.; hi useless resistance is the atmospheric
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Keywords: ., bookcentury1800, bookdecade1840, booksubje, booksubjecttechnology
