STEAM ENGINES 205 



Easing of Throttle Valve. Another precaution that should 

 be taken is the easing of the throttle valve on its seat before 

 steam is let into the main steam pipe; otherwise, the unequal 

 expansion of the valve casing may cause the valve to stick 

 fast and thereby give much trouble. Even if a by-pass pipe 

 is fitted around the throttle, it would be better not to depend 

 on it. Considerable space has been devoted to the subject 

 of warming up and draining the water out of the steam pipe 

 and engine on account of its importance. Water being non- 

 compressible, it is an easy matter to blow off a cylinder head 

 or break a piston if the engine is started when there is a quan- 

 tity of water in the cylinder. 



Oil and Grease Cups. The last thing for the engineer to do 

 before taking his place at the throttle preparatory to starting 

 the engine, provided he has no oiler, is to start the oil and 

 grease cups feeding. It is well to feed the oil liberally at first, 

 but not to the extent of wasting it; finer adjustment of the 

 oiling gear can be made after the engine has been running a 

 short time and the journals are well lubricated. 



Starting Non-Condensing Slide-Valve Engine. A non- 

 condensing slide-valve engine is started by simply opening the 

 throttle; this should be done quickly in order to jump the 

 crank over the first dead center, after which the momentum 

 of the flywheel will carry it over the other centers. The 

 engine should be run slowly at first, gradually increasing the 

 revolutions to the normal speed. When the engine has 

 reached full speed, the drain pipes should be examined; if dry 

 steam is blowing through them, the drain cocks should be 

 closed. If water is being delivered, the drain cocks should 

 remain open until steam' blows through and should then be 

 closed. 



Stopping Non-Condensing Slide-Valve Engine. To stop 

 a non-condensing slide-valve engine, it is only necessary to 

 shut off the supply of steam by closing the throttle, but care 

 should be taken not to let the engine stop on the dead center. 

 After the engine is stopped, the oil feed should be shut off and 

 the main stop-valve closed. The valve should be seated, 

 but without being jammed hard down on its seat. The 

 drain cocks on the steam pipe and engine may or may not 

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