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otner hours the load on the same machine may drop to 50 H. P. In such cases the number of nozzles in action may be reduced by closing the shut-off valves until the required volume of steam is admitted to the wheel. This adds to the economy of the machine. After passing through the nozzles, the steam, as elsewhere explained, is now completely expanded, and in impinging on the buckets its kinetic energy is transferred to the turbine wheel. Leaving the buckets, the steam now passes into the exhaust chamber G, Fig. 147, and out through the exhaust opening H, Fig. 148, to the condenser or atmosphere as the case may be.

The gear is mounted and enclosed in the gear case I, Fig. 147. J is the pinion made solid with the flexible shaft and engaging the gear wheel K. This latter is forced upon the shaft L, which, with couplings M, connects to the dynamo or is extended for other transmission.

O, Fig. 148, is the governor held with a taper shank in the end of the shaft L, and by means of the bell crank P operates the governor valve C. The flexible shaft is supported in three bearings, Fig. 147. Q and Rare the pinion bearings and S is the main shaft bearing which carries the greater part of the weight of the wheel. This bearing is self-aligning, being held to its seat by the spring and cap shown.

T, Fig. 147, is the flexible bearing, being entirely free to oscillate with the shaft. Its only purpose is prevent the escape of steam when running non-co densing, or the admission of air to the wheel case when running condensing. The flexible shaft is made very slender, as will be observed by comparing its size with that of the rotary pump shaft in Fig. 146. It is by means of this slender, flexible shaft that the dangerous feature

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of the enormously high speed of this turbine is eliminated.

The governor is of the centrifugal type, although differing greatly in detail from the ordinary fly ball governor, as will be seen by reference to Fig. 149. It is connected directly to the end of the gear wheel shaft. Two weights B are pivoted on knife edges A with

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hardened pins C, bearing on the spring seat D. E is the governor body fitted in the end of the gear wheel shaft K and has seats milled for the knife edges A. It is afterwards reduced in diameter to pass inside of the weights and its outer end is threaded to receive the djusting nut I, by means of which the tension of the spring, and through this the speed of the turbine, is adjusted. When the speed accelerates, the weights,

affected by centrifugal force, tend to spread apart, and pressing on the spring seat at D push the governor pin G to the right, thus actuating the bell crank L and cutting off a part of the flow of steam.

It has been found necessary with this turbine, when running condensing, to introduce a valve termed a vacuum valve, also controlled by the governor, as it has been found that the governor valve alone is unable to hold the speed of the machine within the desired limit. The function of the vacuum valve is as follows: The governor pin G actuates the plunger H, which is screwed into the bell crank L, but without moving the plunger relative to said crank. This is on account of the spring M being stiffer than the spring N, whose function is to keep the governor valve open and the plunger H in contact with the governor pin. When a large portion of the load is suddenly thrown off, the governor opens, pushing the bell crank in the direction of the vacuum valve T. This closes the governor valve, which is entirely shut off when the bell crank is pushed so far that the screw O barely touches the vacuum valve stem J. Should this not check the speed sufficiently, the plunger H is pushed forward in the now stationary bell crank and the vacuum valve is opened, thus allowing the air to rush into the space P in which the turbine wheel revolves, and the speed is immediately checked.

The main shaft and dynamo bearings are ring oiling. The high-speed bearings on the turbine shaft are fed by gravity from an oil reservoir, and the drip oil is collected in the base and may be filtered and used over again.

The fact that the steam is used in but a single stage or set of buckets and then allowed to pass into the

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