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Indiana University Studies 



2. Cheap foundations as compared to the ordinary boiler 

 and engine plant. 



3. Economj^ in fuel consumption in small plants. Tests 

 have been made on a locomobile of medium power which showed 

 a coal consumption per horse-power per hour as low as If to 

 23^2 pounds; and steam consumption as low as 9.2 pounds per 

 horse-power hour. 



4. Dependability and easy supervision. 



5. Universal application and universal fuel. 



In this engine, steam is generated at a pressure of 175 to 225 

 pounds absolute, and is superheated to 800 degrees Fahrenheit, be- 

 fore it is admitted to the high-pressure cylinder. Exhaust steam is 

 reheated to a temperature of 500 degrees Fahrenheit before it is 

 admitted to the low-pressure cylinder. The feed water is heated 

 by an economizer placed in the breeching. Some of the larger 

 units on test have shown a coal consumption as low as 0.8 pounds 

 per horse-power per hour and many tests have shown as low as 

 1 pound per horse-power per hour. The lowest steam consump- 

 tion recorded is about 7 pounds per horse-power. 



The fact that the locomobile uses superheated steam and runs 

 condensing even in comparatively small units, accounts for its 

 economy over the simple steam engine and boiler plant. 



With regard to the coal consumption and steam used per 

 horse-power per hour the following letter from one of the largest 

 manufacturers of locomobles in this country will probably be of 

 interest. For the sake of comparison I am introducing with it an 

 extract from a letter from one of the large engine manufacturers 

 which gives the steam and coal consumption of a high-grade 

 automatic engine for the same service: 

 Deab Sir: 



In reply to your letter of the 7th stating that you are figuring on an ideal 

 plant for furnishing power for a small stone mill, in any work where economy 

 is desired and over a wide range of load, a locomobile is very well adapted. 

 We are enclosing herewith some power plant tests which we have run on this 

 unit and the coal consumption is the same at three-fourths load and rated 

 load, while at one-half load and one and one-fourth load the increase is very 

 slight, being about 3 per cent more at one and one-fourth load and less than 

 15 per cent at one-half load, while with the ordinary plant the percentage 

 of increase in steam consumption or coal consumption is very much greater 

 at fractional loads. Would say roughly that with coal having 14,000 B.T.U. 

 and not more than 40 per cent volatile matter we can produce a horse-power 

 with a locomobile on 13^ pounds per I.H.P. per hour between thi'ee-fourths 

 and rated load when operating condensing. The amount of coal used for 

 banking the boilers at night would be approximately 10 per cent of the 

 amount used during a 10-hour run. 



