Stationary steam engines, simple and compound; especially as adapted to light and power plants . the valve isproduced by a mechanism which begins and ends its move-ment with the action of the piston; in the Cornish engineit is actuated by the engine beam. It is easy to obtain amotion of this character, by the use of an eccentric, bysimply setting it so as to make its throw directly with, oropposite to, the crank. In such a case, it is seen that theExhaust valve must be driven by an independent eccentric,and the cost of the engine is thus somewhat is not a large item, however. Th
Stationary steam engines, simple and compound; especially as adapted to light and power plants . the valve isproduced by a mechanism which begins and ends its move-ment with the action of the piston; in the Cornish engineit is actuated by the engine beam. It is easy to obtain amotion of this character, by the use of an eccentric, bysimply setting it so as to make its throw directly with, oropposite to, the crank. In such a case, it is seen that theExhaust valve must be driven by an independent eccentric,and the cost of the engine is thus somewhat is not a large item, however. The Greene engine,is an engine fitted with such a valve-motion. ELECTRIC LIGHTING PLANTS. 41 In the accompanying illustration, which exhibits thismachine, the valves are seen to be four in number, as in theengines already described. They are flat valves, instead ofcylindrical, and are thought by the inventor to be betterthan the latter, as being easier to refit when worn, and asbeing less liable to become leaky. The cut-off mechanismconsists of a sliding bar, A^ driven by an eccentric, set to. Greene Valve Motion. give it motion parallel to the centre line of the cylinder, andwith a movement co-incident, as to time, with the motionof the piston; of a pair of tappets, C, C, set in this bar I. Manual of the Steam Engine, Vol. I. p. I02. 42 STEAM ENGINES FOR and adjustable vertically in such a manner as to engage therock-shaft arms, B, B, on the ends of the rock-shafts, E, F^which rock-shafts are attached to the valve-links inside thesteam chest; of a set of springs which hold these tappetsup to their work, and in contact with the gauge-barbehind the bar, A, and out of sight in the drawing. Thisgauge-bar is adjusted to the proper height, and is varied inposition, as the load varies, by the action of the governorwhich is connected to the gauge-bar by the rod extendingup to it at G. The exhaust valves are seen below, and aredriven by the second eccentric there shown. They are soplaced
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectsteamen, bookyear1902
