320 



FARM MOTORS 



Since the shell of the fire box is under external pres- 

 sure, it must be stayed to avoid collapsing. The blow- 

 off cock and frequent hand holes are near the base for 



FIG. 215 EXTERNALLY FIRED BOILER 



A A, boiler setting; BB, boiler front; CC, boiler shell; DD, flues; E, flue door; F, 

 handhole; G, flue sheet; //, bracket; /, steam dome; /, safety valve; K, steam 

 pipe; L, steam gauge; J/, steam gauge syphon; NN, try cocks; 0, water 

 glass: PS, blow-off pipes; Q, blow-off valve; TT, fire door; U, fire door lining; 

 V, ash door; IV, grates- X, bridge wall; Y, ash pit; Z, britchen; A, damper. 



convenient cleaning. A water glass and try cocks are 

 near the top. Heating surface in this type of boiler con- 

 sists of the fire box and the fire tubes up to the water 



