BOILER AND MANAGEMENT 329 
Care of Injector. An injector will become coated 
with sediment or scale the same as the boiler and must, 
therefore, be frequently cleaned. This is best done by 
immersing it in a solution of one part muriatic acid and 
ten parts water. Allow to remain in this solution until 
the scale becomes soft enough to permit washing out. A 
clean injector rarely causes trouble but if trouble does 
occur it may be due to : (1) low steam pressure; (2) too 
hot water; (3) leaks in pipes and injector; (4) clogging 
of water pipe; (5) wet steam; (6) poor working condi- 
tion of check and overflow valves; (7) clogging of feed 
pipe where it enters the boiler. 
The injector is commonly used to feed water into the 
boiler because it is cheap and simple, and occupies little 
space. 
Pumps. There are two kinds; (1) those run with 
steam directly, and (2) those run by the engine. The 
latter is the more economical and handles hot water with 
less trouble. It has one disadvantage, however, and that 
is it does not work unless the engine is running. With 
good pumps, especially those run by the engine, good 
work may be expected when the feed water has been heat- 
ed to 200° F. with the exhaust steam from the engine. 
With the injector such high temperatures are not per- 
missible, hence the greater economy of the pump. The 
great saving of fuel by feeding water hot into the boiler 
is illustrated by experiments made by Jacobus which 
show that with a direct acting pump 12.1% fuel is saved 
by heating the feed water from 60° to 200° before pump- 
ing it into the boiler. With injectors the feed water used 
usually has a temperature of about 60° F. 
Steam. Water is practically a non-conductor of heat. 
This means that it cannot conduct its heat to its neighbor- 
