. A text book of physics, for the use of students of science and engineering . of thepiston. These rings press outwards against the walls of the piston rod and valve rod pass through stuffing boxes in the endof the cylinder and valve chest, and are thus rendered steam tight. Steadiness of rotation of the crank shaft G is secured by meansof a heavy flywheel which is fixed to the shaft. The engine is 506 HEAT CHAP. maintained at approximately constant speed by means of a governorA (Fig. 464). Two heavy balls FF are mounted at the ends of arms GG,which are attached at their upper end
. A text book of physics, for the use of students of science and engineering . of thepiston. These rings press outwards against the walls of the piston rod and valve rod pass through stuffing boxes in the endof the cylinder and valve chest, and are thus rendered steam tight. Steadiness of rotation of the crank shaft G is secured by meansof a heavy flywheel which is fixed to the shaft. The engine is 506 HEAT CHAP. maintained at approximately constant speed by means of a governorA (Fig. 464). Two heavy balls FF are mounted at the ends of arms GG,which are attached at their upper ends by pins to a spindle H. The spindle is rotated by a beltfrom the crank shaft runningon the pulley K, the motionbeing transmitted to H bymeans of bevel wheels arms MM connect theballs to a sleeve N which canslide on the spindle H. Aheavy weight P is carried bythe sleeve. A bent lever Qhas one arm connected to acollar embracing the sleeve,and the other arm is con-nected bv a rod S to thethrottle valve lever E. When the engine is running,centrifugal force acts on the. -Diagram showing how the governorcontrols the steam supply. balls, causing them to move Fig. 464 outwards until a steady position is reached which depends upon the speed of rotation. Anyincrease in speed will cause further outward movement of the balls,producing an upward movement of the sleeve N. This movement istransmitted to the throttle valve C, and causes it to close partiallythe steam-pipe B. Thus the supply of steam to the engine isreduced, and the speed falls again. Reduction in speed below thenormal causes the balls to move inwards, and the throttle valve isconsequently opened to a greater extent, thus increasing the supplyof steam to the engine. The student is referred to the section on Dynamics, Chaps. XVI., for the theory of the action of flywheels and governors. Thermal efficiency of a steam engine.—In practice the heat suppliedto a steam engine is taken as the difference between the t
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
