FARM MOTORS 



383 



to heat the water as it is forced into the boiler. The heat 

 thus saved may amount to as much as ten to fifteen per cent. 

 Boiler Management. In managing the boiler care should 

 be taken to see that the flues are kept free of soot, in order 

 that the heated gases may come in direct contact with the 

 metal, and that the boiler is kept clear of incrustation on 

 the inside. Such accumulations do not have the heat-con- 

 ducting properties of the steel and result in a serious loss of 

 heat. If the scaly deposits from the water become too thick, 

 the heat may not be carried away from the plate fast enough 

 to prevent it from becoming overheated. Thus care should 

 be taken not only to use water which is free from foreign sub- 

 stances, but also to clean the boiler frequently. 



Fig. 246. A feed water heater in which the water is heated by the 

 exhaust steam. 



Foaming sometimes occurs in a boiler, due largely to the 

 presence of dirt, alkali, grease, or other foreign matter. It 

 causes a large amount of water to be carried away with the 

 steam, and prevents the engineer from determining accu- 

 rately the true level of the water. Great care should be taken 

 in managing the boiler when foaming takes place. 



Low water in a boiler should always be guarded against; 

 and if at any time it should occur, the further generation of 

 heat should be stopped and the boiler allowed to cool. It is 

 inadvisable to try to remove the fire, as it is quite sure to 

 increase its intensity. The best procedure is to cover tne 



