210 STEAM EXGIXES 



When the signal to start the engine is received, it is only 

 necessary to throw the valve gear into the go-ahead or backing 

 position, as the signal requires, and to operate the throttle 

 according to the necessities of the case, for which no rule can 

 be laid down beforehand, as the position of the throttle will 

 depend on the load on the engine at the time. 



Starting and Stopping Compound Corliss Engine. The 

 operation of starting and stopping a compound Corliss engine 

 is precisely similar to that of starting and stopping a simple 

 Corliss engine. The high-pressure valve gear only is worked 

 by hand in starting, the low-pressure eccentric hook having 

 been hooked on previously. The low-pressure valve gear is 

 worked by hand only while warming up the low-pressure cylin- 

 der. The directions given for operating the simple condensing 

 engine apply to the condensing Corliss engine, so far as the 

 treatment of the air pump, circulating pump, and condenser 

 is concerned. 



POUNDING OF ENGINES 



Loose Brasses. Loose journal brasses are the most frequent 

 cajse of pounding in engines. The remedy for pounding of 

 this nature is obvious. The engine should be stopped and 

 the brasses set up gradually until the pounding ceases. In the 

 case of shaft journals, they may be set up without stopping 

 the engine, provided the engineer can reach them without 

 danger of being caught in the machinery. 



Brass-Bound Bearings. It may so happen that the boxes 

 or brasses are worn down until the edges of the upper half 

 and those of the lower half are in contact and cannot be set 

 up on the journal any farther; they are then said to be brass 

 and brass, or brass-bound. In a case of this kind, the journal 

 must be stripped, as it is called, when the cap and brasses 

 are removed from a journal. The edges of the brasses are 

 then chipped or filed off, in order to allow them to be closed in. 



Liners. It is a most excellent plan in practice to reduce 

 the halves of the brasses so that they will stand off from each 

 other when in place for a distance of J to A in. and to till this 

 space with hard sheet-brass liners from 20 to 22 Birmingham 

 wire gauge in thickness, or even thinner. Should the journal 

 become brass-bound, the cap may be slacked off and a pair 



