26o DEVELOPMENTS IN OIL BURNING. 



shown in Fig. 17, various other air distributors were tried, but none of these 

 seemed to promise as well as the impeller, either as to smokelessness, gas 

 analysis, ignition of the oil, or noise. 



WYOMING TESTS. 



Coal. — The contracts for the United States battleships Wyoming and 

 Arkansas called for a series of four 24-hour guarantee tests with coal, the first 

 to be at a rate of combustion of 15 pounds, the second at 25 pounds, the third 

 at 35 pounds, and the last at 40 pounds of coal per square foot of grate 

 surface per hour. The idea was to duplicate a possible severe war condition, 

 and it was required that the evaporation per pound of combustible in the final 

 test should not be less than 11 pounds of water from and at 212°. This re- 

 quirement was increased to ii| pounds for the next contract after obtaining 

 the excellent results in the tests on the Wyoming boiler. 



As both the U. S. S. Wyoming and the U. S .S. Arkansas were fitted with 

 Babcock & Wilcox boilers, and as both these ships were to burn oil in combi- 

 nation with coal, it was decided to build a special test boiler of exactly the 

 same design and proportions, except that it was not as wide, set this up at 

 the works, with an air-tight house around it, force air into this house under 

 pressure to duplicate the conditions of a closed fire-room on board ship, and 

 after making the guarantee tests with coal continue the experiments with 

 oil, and with oil and coal in combination. This plan proving acceptable to 

 the Engineer in Chief of the Navy, the boiler was built and tested under 

 guarantee conditions by a board of naval officers, of which Capt. C. W. Dyson 

 was the senior member. 



As this same boiler was later tested with oil fuel, the comparison with 

 coal is of general interest, and I have therefore copied the results of the coal 

 tests from the board's reports (Table II). It will be noticed that a fifth test 

 was made at the high rate of combustion of practically 70 pounds of coal per 

 square foot of grate per hour. This was not part of the guarantee but was 

 made at the request of the builders to show the possibiUties of forcing the 

 boiler. In this test, 14.76 pounds of water were evaporated from and at 

 212° per hour per square foot of heating surface. 



Preliminary Tests with Oil Fuel. — After the completion of the coal tests 

 the boiler was thoroughly cleaned of soot and ashes, fire-bricks were laid on 

 the grate bars, and the front was arranged to receive the oil burners and air- 

 distributing device. 



While the results of the IdaUa experiments had been promising it was 

 desired to materially increase the capacity, .45 pound of oil per square foot 

 of heating surface and about 6.2 pounds per cubic foot of furnace volume 



