MECHANICAL POWER FOR THE FARM 



451 



freezers, washing machines, feed grinders, ensilage cutters, corn 

 shellers, hay presses, binders, spraying machines, wood saws, 

 cement mixers, rock crushers, and grindstones, and for many 

 other uses about the dairy barn and the farmhouse. By con- 

 necting an oil engine to an electric dynamo, electricity can 

 be generated for farm lighting. The oil engine has also been 



v K 



FIG. 225. Fundamental parts of a steam engine 



Steam pipes convey the steam from the boiler (not here shown) to the engine. The 

 steam from the boiler enters the steam chest K and is admitted alternately to either 

 end of the cylinder A by the valve V. The steam entering the cylinder A pushes on 

 the piston P. The motion of the piston is transmitted through the piston rod R 

 to the crosshead H, and through the connecting rod M to the crank disk D, which 

 is keyed to the crank shaft S. The crank shaft is connected directly or by means 

 of belts to the machines to be driven ; it is supported on two bearings, B and O, 

 and carries the flywheel W, the function of which is to make the speed of the 

 engine more uniform 



used with great success for propelling automobiles, trucks, and 

 traction engines, and its use is increasing. 



592. Action of gas engines and oil engines. The gas engine 

 and the oil engine differ from the steam engine in that the 

 entire transformation of the heat energy of the fuel into work 

 takes place within the engine cylinder. The fuel in the case of 

 the gas engine may be natural gas or some form of artificial gas 

 manufactured from coal or oil. The fuels for oil engines are 

 gasoline, kerosene, and crude petroleum. Alcohol has also been 



