332 



FARM MOTORS 



FIG. 228 INDEPENDENT PLUNGER 

 PUMP 



can be run at any time and 

 of this is more than that 

 of other types. 



453. The injector i s 

 probably the most gen- 

 erally used means o f 

 feeding boilers. It was 

 invented in 1858 by M. 

 Giffard, and large num- 

 bers of the same types 

 are still made. The ac- 

 tion of the injector will 

 be understood by refer- 

 ring to the sketch 

 (Fig. 229). Steam is 

 taken from the boiler 

 and passes through the 

 nozzle A to the injector; 

 the amount of steam is 



acting (Marsh) pump, and 

 the independent plunger 

 pump (Figs. 226, 227, and 

 228). The crosshead type 

 is the simplest and most 

 economical, but can be run 

 only when the engine is 

 running. The Marsh inde- 

 pendent pump is simple and 

 economical, but the action 

 of its steam valve is deli- 

 cate and should be molested 

 only by an expert. The in- 

 dependent plunger pump is 

 very satisfactory in that it 

 by any one. The initial cost 



FIG. 22Q PRINCIPLE OF THE 

 INJECTOR 



