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346 ~ of the helix K. By this arrangement the combustion of the oil is under com- plete control, and the vaporization is very complete. At the point where combustion is about to commence a fur- ther supply of compressed air is given, and a third supply is added by the draught which comes through the fire- bars, and in special cases through a hol- low furnace-front, and passes between the inner and the outer plates, and es- capes through a coned opening round the burner. When the air-compressor is under re- pair or examination, the oil-fuel burn- ers can be operated by means of low- pressure steam, which is superheated on. its way to the burners by means of a suitable heating apparatus. -- Turbo-Air _ Compressor. On board ship the use of a turbo air- compressor is advantageous, as it makes for lightness and neatness. advantage of this system lies in the fact that no alteration of the boilers, as arranged for coal-firing, is needed, and the change fom liquid fuel to solid - fuel, or vice versa, can be made in- stantly, and without loss of steam pres- sure. It is claimed that the air-com- pressor absorbs less than 2 per cent of the steam raised, and this steam is condensed and returned to the boilers as hot feed. The steam jet burner is shown in longitudinal section in Fig. 2. The oil enters. the burner through the branch B, and has a whirling motion given to it by the prolonged spiral stem of the valve spindle G, the amount of oil be- ing governed by the hand-wheel N at the end of the spindle A. The steam enters at C around the hollow cone H and passes through slots (not shown) in the cylindrical portion of this cone, where it fits the inside of the hollow air-cone F. It will be seen that in this way all the oil passing through the burner is steam-jacketed. The air-cone F is also fitted with spiral guides, and the air is drawn past these guides through the openings D by the inductive action of the steam. The amount of air passing may be regulated by means of the movable perforated strap E. On the front portion of the burner is the part marked F, which is so arranged that it can be screwed in or out as a whole, being turned by the spider M. When moved, it carries with it the cone F, and in so doing regulates the space between this and the oil-cone H for the escape of the steam. As the range of adjustment is large, the same burner may be used for different pow- ers within wide limits. When the burn- er is started, the steam opening is first A further | THE Marine REVIEW adjusted by trial, which is done by un- screwing the front of the burner, so that the space between the cone H and that marked F allows the minimum amount of steam required for atomiza- tion to pass through. The amount of opening for induced air is readily de- termined by the character of the flame and the sound of the fire when in op- eration. The flame should be transpa- rent and of an intense white color or approaching pink when using light oils. The steam-jet burner may be operated by means of steam or air, and in the case of this burner, as well as that of the air-jet burner, no alteration of the furnace, as arranged for coal, is neces- sary. When oil is to be the only fuel used, however, there is no object in fitting fire-bars, and a suitable arrange- ment of brickwork is provided. It is claimed that the steam-jet system just described will recover from 68 to 74 per cent of the calorific value of the fuel used in actual work. Pressure Jet Burner. The latest type of Kermode burner brought out is the pressure-jet burner which has been specially designed for naval and other vessels, and it is rec- ommended for use with forced or in- duced draught. The burner is shown in longitudinal section and in plan re- spectively in Fig. 3. The oil fuel en- ters the burner through the channel marked A in Fig. 3 and passes between the outer wall of the burner marked D, and the inner cylinder marked B, which abuts against the cap-nut &. The end of the cylinder B is an exact fit in the outer casing D where it abuts against the nut £, and in this end of B a num- ber of grooves are cut parallel to the center line of the ,burner, while there are similar grooves in the end of the part B at right angles to the axis of the burner. These grooves are shown at H in Fig. 3, and it will be seen that they are tangential to the cone end of the spindle C, which serves to contract, or enlarge, the opening through the cap-nut E£. The movement of C is in- dicated on the graduated wheel F. By means of this arrangement the oil fuel is atomized very completely, by be- ing forced through a restricted open- ing with a rotary motion, which is giv- en to it by the tangential grooves in the face of .the plug B, and it is dis- tributed in the form of a cone by means of the reaction or deflection which is set up by the oil impinging on the cone end of the spindle C. The fixed pointer marked G serves to indicate the degree to which the wheel F has been rotated, either to increase or diminish the open- ing through the nut E. With this burn- side of the force-pumps. September, 1910 er neither steam nor air is required to disintegrate the oil, the pulverization being effected by means of the pressure which is brought to bear upon the oil fuel itself by means of a force-pump. Before use, the oil is heated and care- fully filtered. A complete outfit of this pressure jet system has just been supplied to a steamer which is being built in Java, the installation being shown in Figs. 4 and 5. There are two Yarrow type water-tube boilers, each with a heating surface of /50 sq. ft. Forced draft is used, as may be noted, on the closed ashpit system, and each of the boilers can be worked separately so that the full power can be obtained from one boiler should circumstances demand. The arrangement of the installation is clearly shown in Figs. 4 and 5. The oil-fuel suction-pipes may be seen at 4, Fig. 5, and the oil force-pumps at B, Fig. 4. C is a spring-loaded relief-valve with a return branch to the suction The oil-fuel filters fitted in duplicate are shown at D, the oil-fuel heater at E, the burners at F, and the fan for supplying the forced draft at G. The fires are started initially by means of the hand-pump H. The steam which is used for driving the oil force-pumps and for heating the fuel is condensed and returned to the feed-tank, so that no water is lost, as with the steam-jet system. It is claimed that with the pressure-jet sys- tem the saving of feed-water, the light- ness of the equipment, and its im- munity from breakdown through the duplication of force-pumps and filters are. considerations which have decided its adoption for use on warships. This system is said to recover from 70 to 75 per cent of the calorific value of the fuel used in actual work. Contract for Harbor Tugs The Department of Docks and Ferries, of the City of Philadelphia, has award- ed to the Waters-Colver Co., of West New: Brighton, S. I., the contract for building two new tugs for use in Phila- delphia harbor. One tug 'will be 81 ft. long, 20 ft. wide and 9 ft. depth of hold. The propelling machinery consists of a fore and aft compound engine with cyl- inders 12 in. and 26 in. by stroke of 18 in. The other tug will be 66 ft. long, 16 ft. wide and 17 ft. depth of hold, with propelling machinery consisting of a single high-pressure engine 14 in. by 14 in. Contract for the enlargement of the naval dry dock at Norfolk, Va., has been awarded to William L. Miller, of Bos- ton, for $523,784. Ti i cA ak Bk ah Le