The Koerting system is the outcome of a number of experiments conducted by Schutte-Koerting Com pany of Philadelphia, Pa. Fig. 87 shows a sectional view of boiler fronts with the Koerting system ap plied to a water tube boiler. C is the air register, fitted with air admission slides to regulate the air that is required around the burner ; and B indicates the automatic air doors that regulate the amount of air necessary to complete the combustion of the oil.
The "Dahl" mechanical fuel oil system has been adopted by many of the steamship companies on the Pacific Coast. It was the first mechanical system to successfully operate with the heavy California oils. The burner is extremely simple, having only a few parts, consisting of a tip, atomizer, strainer, tube and valve. The operation of the burners is regulated by the pressure on the oil line, rather than the valve of the burner.
The furnace front as shown in Fig. 89 is of ap proved construction, so arranged that the burner passed through a pipe, on the end of which is a cone or deflector which can be adjusted by moving it in or out to insure the proper quantity of air just where it is needed. The front is extended so that the whole length of the furnace is utilized, and the brickwork is so fitted that repairs and examinations can be made without removing it. Fig. 88 shows an outline of an installation on a Scotch marine boiler, arrange ments of pumps, heaters, etc., being clearly indicated.
Fig. 91 illustrates the Tate-Jones pressure jet burner and furnace front. The oil is fed to the burner at 125 to 200 lb. pressure, and passes through tan gential slots in the burner tip, where it attains a high velocity of rotation in the vortex chamber, and es capes through the opening in the end of the burner as a fine mist in the shape of a hollow cone.
The amount of air needed for combustion is reg ulated by the damper on the air cone of the furnace front. The range of regulation is sufficient to make it adaptable for either natural or force draft. Inside the air cone are fixed the air impellers or blades, which give a rotary or whirling motion to the entering air. This whirling motion mixes the entering air with the oil mist much better than when the air enters in straight lines.
Most types of mechanical atomizers will produce a fine spray of oil ; the important problem is to secure a furnace design and arrangement which will insure proper distribution of the air. A test was recently
conducted on the steam yacht "Idalia." This vessel is fitted with a Babcock & Wilcox marine boiler, con taining 2560 sq. ft. of heating surface. A simple and effective system of induced draft fans was installed, capable of giving a suction in the uptake of 1 to 1% in. of water, and in addition to this a forced draft fan was set up on the dock and connected by means of a flexible duct to a sheet casing enclosing the oil burn ers in front of the boiler. The tanks and scales for weighing the oil and water and the oil pump and heater were set up on the dock and connected to the vessel by means of flexible pipes, the regular feed pump of the plant being used for taking weighed water from the filter box. The engines and other auxiliaries were not in use, the steam discharged to the atmosphere through a muffler arranged to maintain regular work ing pressures on the boiler. All precautions were taken to prevent leaks and secure accurate data. Fifteen evaporative tests were made, under a variety of conditions, the results being given in the table below. Between these tests, considering experimenting was done with various air-distributing arrangements, flat burners, etc. The best performance was an evapora tion of 7.47 lb. of water per square foot of heating sur face per hour from and at 212 degrees, F., at an ef ficiency of 82.8 per cent at a rate of combustion of 6.17 lb. of oil per cu. ft. of furnace volume per hour with a draft in the uptake of .84 in. of water Other tests were made on the United States bat tleship Wyoming with coal as fuel, oil as fuel, and a combination of coal and oil. The oil was sprayed over the coal fire, a flat flame being secured by adjust ing the admission of air. The capacity of the boilers can be increased by using oil in this manner, but ef ficient results are obtained only when either fuel is used alone.
They operate six boilers with coal and six boilers with oil on the run between San Francisco, Cal.. and Yokohama, Japan ; and the twelve boilers with coal between Yokohama and Hongkong, or about thirty days using oil under six boilers and coal under the other six boilers, and ten days using coal under all twelve boilers.