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Indiana University Studies 



reciprocating engines and turbines. Either of these types may 

 be run either condensing or non-condensing. In the reciprocat- 

 ing engine, the moving parts, including the piston, connecting 

 rods, etc., stop and reverse their direction of motion twice during 

 each complete revolution of the flywheel. That is, the piston 

 is constantly passing the same point but reversing its direction 

 of travel. In the turbine all the moving parts are rotating with 

 a constant motion. The term non-condensing, when applied to 

 an engine, indicates that the steam from the cylinders Is exhausted 

 against a back pressure equal to the pressure of the atmosphere, 

 which is approximately 14.7 pounds per square inch. This 

 back pressure can only be reduced by exhausting the steam 

 into as high a vacuum as can be maintained by the engine pumps. 

 This gives an added pressure on the pistons equal to the amount 

 of vacuum that can be maintained. The saving due to the use of 

 condensers on small power units is not enough to justify the 

 expense of installing condensers, but as soon as the plant reaches 

 a fair size they are an economical proposition. In the steam 

 turbine the steam is driven against the blades of a fanlike rotor 

 by means of a single set of nozzles, in the single-stage turbine, 

 or thru a series of nozzles, in the multi-pressure types. The low 

 first cost and adaptability of the turbine to driving generators 

 make it an ideal prime mover in such plants. 



Producer Gas and Producer-Gas Machinery. There 

 are three principal natural fuels: coal, oil, and gas. Of these we 

 are most familiar with coal for the reason that its use as a source of 

 power has been known longer and the deposits are more wide- 

 spread. Oil carries the most stored energy, but the supply is 

 more limited. Gas is the most convenient, but the supply of 

 natural gas is already decreasing and its use is confined to small 

 areas where it occurs. The experiments with natural gas as a 

 source of power have led to the production of artificial gas. 



The use of steam machinery as a means of power generation 

 is admitted by everyone who has gone over the figures to be a 

 most extravagant waste of our coal resources. Yv^ith the country- 

 wide cry for a better conservation of our natural resources, the 

 coal situation has occupied the attention of thinking people 

 more than any other issue. It would seem that if any consider- 

 able portion of the heat in our coals which is being lost by our 

 present methods of power generation is to be saved, it will have 

 to be by some other method than by improving steam power 



