A history of the growth of the steam-engine . There are two engines, having steam-cylin-ders 14 inches in diameter and of the same length of stroke,direct-acting, condensing, and driving a screw, of 7 feetdiameter and of 10^ feet pitch, 135 revolutions a minute,giving the yacht a speed of 13^ knots an hour. In larger vessels, as in yachts, in nearly all cases, theordinary screw-engine is direct-acting. Two engines areplaced side by side, with cranks on the shaft at an an-gle of 90° with each other. In merchant-steamers thesteam-cylinders are usually vertical and directly over thecrank-pins, to
A history of the growth of the steam-engine . There are two engines, having steam-cylin-ders 14 inches in diameter and of the same length of stroke,direct-acting, condensing, and driving a screw, of 7 feetdiameter and of 10^ feet pitch, 135 revolutions a minute,giving the yacht a speed of 13^ knots an hour. In larger vessels, as in yachts, in nearly all cases, theordinary screw-engine is direct-acting. Two engines areplaced side by side, with cranks on the shaft at an an-gle of 90° with each other. In merchant-steamers thesteam-cylinders are usually vertical and directly over thecrank-pins, to which the cross-heads are coupled. The con-denser is placed behind the engine-frame, or, where a jet-condenser is used, the frame itself is sometimes made hol-low, and serves as a condenser. The air-pump is worked bya beam connected by links with the cross-head. The gen-eral arrangement is like that shown in Figs. 137 and naval purposes such a form is objectionable, since itsheight is so great that it would be exposed to injury by. Fig. 186.—Horizontal, Direct-acting Naval Screw-Engine. shot. In naval engineering the cylinder is placed horizon-tally, as in Fig. 136, which is a sectional view, representingan horizontal, direct-acting naval screw-engine, with jet-condenser and double-acting air and circulating pumps. Ais the steam-cylinder, Ji the piston, which is connected tothe crank-pin by the piston-rod, I>, and connecting-rod, JS. 390 THE STEAM-ENGINE OP TO-DAY. F is the cross-head guide. The eccentrics, G, operate thevalve, -which is of the three-ported variety, by a Stephen-son link. Reversing is effected hy the hand-wheel, G,which, by means of a gear, m, and a rack, k, elevates anddepresses the link, and thus reverses the valve. The trunk-engine, in which the connecting-rod is at- ^1
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Keywords: ., bookcentury1800, bookdecade1870, bookidc, booksubjectsteamengines
