HEAT VALUES OF COAL

B.T.U. PER POUND OF DRY COAL-CALORIES PER KILO. DRY COAL

ENGLAND, GERMANY, FRANCE, BELGIUM, AND AUSTRIA-HUNGARY

The following table, from M. Pouillet, will enable the temperature to be judged by the appearance of the fire:

Copyright by N. L. Stebbins

ARGENTINE BATTLESHIPS "RIVADAVIA" AND "MORENO " BABCOCK & WILCOX BOILERS, 39,500 S. H. P.

ADVANTAGES OF LIQUID FUEL FOR MARINE BOILERS

T

HE many advantages of liquid fuel or fuel oil for use with steam boilers have been apparent for a long time, and, in localities where the crude oil or refuse from distillation could be obtained cheaply (or where coal was very expensive, as in California) it has been used with much satisfaction. As far back as 1893, Colonel Soliani of the Italian Navy read a paper giving details of elaborate trials of petroleum refuse as fuel, and in 1902-3 an extended series of tests of various forms of burners with crude oil was made, under the direction of the late Admiral Melville, U. S. Navy, by a Board of Naval Engineers.

In all of these tests, the oil was sprayed or atomized by steam or compressed air. Although excellent results were obtained, it was realized by all marine engineers that the problem was not yet successfully solved for sea-going vessels operating away from a ready supply of fresh water. What was needed was a burner which would efficiently atomize or spray the oil by pressure alone, or, as it is usually called, mechanical atomization.

at sea.

The Babcock & Wilcox Company had developed an efficient steamatomizing burner which has been extensively employed with its land boilers, and it then proceeded to develop a mechanical-atomizing burner for use Such a burner was developed which gave excellent results up to a rate of combustion about equal to Navy forced draft practice with coal, but it was realized that higher rates must be made practicable if the full benefit of oil fuel was to be obtained. Further experimentation made it clear that the burner was equal to any demand, but that the proper admission and admixture of air was of at least equal importance. This led to the invention of an air register or impeller which enabled extremely high rates of combustion to be obtained without smoke and with high efficiency. The burners and registers have now been fitted to a number of naval and merchant steamers where they have given great satisfaction.

In November and December, 1910, a boiler at the Company's works, fitted with these burners and registers, was subjected to a series of tests by a Board of Naval Engineers (which is reprinted in Table XXIII.). In one of these tests the rate of combustion was 1.16 pounds of oil per square foot of heating surface with an evaporation of nearly 16 pounds from and at 212° per square foot of heating surface. The Board stated that this was the highest rate of forcing of which there was any record. (It is equivalent to about 75 pounds of coal per square foot of grate.)

In March, 1913, a series of tests was conducted by Lieutenant-Commander John J. Hyland, U. S. N., at the Fuel Oil Testing Plant, Philadelphia Navy Yard, on a Babcock & Wilcox boiler which is the same as one of the units supplied for the U. S. S. "Oklahoma" (12 boilers in all). This boiler