HE expenditure for locomotive fuel on our stellm railroads amounts to nearly 25 per cent of the total cost of conducting transportation. This ·enormous item of expense, coupled with the ever increasing cost of all material, due to the high price of labor, presents a problem which has engaged the attention of locomotive engineers for a number of years. Experiments made in the way of burning solid fuel other than on grates in cement kilns and metallurgical furnaces have been successful, and

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... ized coal is now extensively used for such purposes; but the diffi culties inseparable from the conditions under which a locomotive has to be operated are great, and it is only recently that appliances· for burning powdered fuel in locomotive fire-boxes have been practically developed. A paper on the subject was presented at a meeting of the New York Railroad Club recently, and by the courtesy of the club we are now able to giye some particulars of this important step in railroad fuel econ omy. In the first place, it may be stated that any solid tuel which in a dry pulverized form has two thirds of its content combustible will be suitable for steam gen. erating purposes. Therefore, the low yalue coal mine and strip-pit products, such as dust, sweepings, culm, slack and screenings, and even lignite and peat, are as suitable as the larger sizes and better grades of coal. As some of the prou.ucts above named are now unsal able, the great saYing effected by the use of the new form of fuel will be apparent; for th . e total cost to prepare pulverized coal in a properly equipped plant will be something less than 25 cents per ton. This item will be more than offset by the great Qifference in the cost of the grades of coal purchased for pulverizing as compared with those that would be required for burn ing satisfactorily on grates. The preparation of the fuel is not complicated. It must be thoroughly dry; that is to say, the moisture should not exceed one per cent, and ground to a fineness so that it will pass through a screen from number 100 tv number 200 mesh. The first locomotive of any considerable size tc be fitted up in the United States or Canada (ane, so far as known, in the world) with successful apparatus for burning pulverized fuel in suspension was a 10-wheel type of engine on the New York Central Railroad. This engine has cylinders 22 inches diameter by 26 inches stroke. Driving wheels, 69 inches diameter. Boiler pressure, 200 Ibs. Heating surface, 2,649 square feet. Grate area, 55 square feet. It is equipped with a Schmidt superheater and has a tractive effort of 31,000 pounds. It was converted into a pulverized fuel burner in the early part of 1914. Since then, other in stallations have been made to a Chicago and North Western Railway " Atlantic" type of engine, and to a new" Consolidation" type of locomotive for the Dela ware and Hudson Company, which latter is probably the· largest of its type in the world, its tractive effort being about 63,000 pounds. To give the reader an idea of the pulverized fuel burning equipment as applied to a locomotive engine, we present an illustration showing the general arrange ment partly in section. The prepared fuel is passed into the fuel container, 1 (which is a part of the ordi nary locomotive tender), through the openings 2, 2. These openings are then tightly closed to keep out moisture, as dryness of the fuel is the prime requisite. To start the fire, the first thing the fireman does is to turn on the steam blower, 27, in the smoke box; then he places a piece of lighted oily waste in the furnace, 24, after which he starts the motor, 17, driving the fuel conveyor, 3, and then the motor, 14, which drives the air blower, 13. The screw conveyor, 3, forces the fuel into the fuel and pressure air feeder, 4, where it meets the air driven by the blower, 13, through conduits 16. The fuel and air are thus driven through a commingler, 5, conduits 6 and 7, nozzle 8 and fuel and air mixer 9. This mixture then enters the combustion furnace 24, which is the ordinary locomotive fire-box provided with a fire-brick floor in place of grate oars, and is there ignited by the lighted cotton waste. The fire-box is fitted with brick arches, 21 and 22, and auxiliary air inlets, 23. There are also induced air inlets,. 11, to secure perfect combustion and a slag pan, 25, in place of the usual ash pan. The air and fuel control regulators, 12 and 18, are Diagram illustrating the operation of the gas turbine There are several of the vessels shown in cros .... section, together building up the base of the ap p aratus. Each has an air valve, a gas valve and an outlet valve Cross-section through one of the explosion chambers of a German gas turbine in the cab within reach of the fireman, who has no need to go illtO the tender, but can keep his place in the cab and assi3t the engine driver in looking ahead for sig nals. The fireman's duties will be very light compared with his work required in hand firing coarse coal on the ordinary grates. This is easily understood when we recall that the . fireman of a heavy modern locomotive has to shovel coal into the fire-box at the rate of about 6,000 pounds an hour, or 100 pounds per minute. This laborious work cannot be done with the care necessary to secure good .combustion, with the result that quan tities of coal are dropped into the ash pan, the flues are rapidly choked with soot, and clouds of smoke, unburnt coal and sparks are ejected from the stack, to the annoyance of passengers and danger to property adjacent to the railway. © 1916 SCIENTIFIC AMERICAN, INC The improved system will change all this, for even when the fuel contains 15 per cent of non-combustible matter only about 2.5 per cent is deposited in the slag or ash pan, and this deposit is non-combustible. Where as, when coal is burned on grates about 15 per cent goes into the ash pan, and this residuum always con tains more or less combustible matter. The saving in ash pan waste alone is an important item. When the proportion of powdered coal and air is properly regulated, the mixture bursts into a clear, intense flame in the fire-box, having a temperature of from 2,500 to 2,900 deg. Fahr.; with no visible· smoke at the stack (except when the fire is first started) and making but little soot deposit in the tubes. With this system of easy and rapid control of the fire it takes less than 60 minutes to get up 200 pounds of steam pressure from boiler water at 40 deg. Fahr. When the engine is standing the fire may be put out entirely, and within an hour can be reignited from the heat of the brick arches in the fire-box. Only one set of fuel and pressure air feeders could be shown in our illustration, but as many, as five units may be placed in the ordinary tender. As each unit has a capacity of from 500 to 4,000 pounds of pulver ized fuel per hour, there will be no difficulty in meeting the requirements of the largest locomotives. It is stated that the use of pulverized fuel effects a saving of from 15 to 25 per cent in coal of equivalent heat value delivered, as compared with the hand firing of CQarse coal on grates. In conclusion it must be noted that there is a certain element of danger in the handling of pulverized coal that does not obtain with the more ineffective coarse coal. But, with ordinary care and the observance of certain established rules, it is comparatively easy to avoid trouble, as is shown by the records of industrial plants using pulverized fuel. W HAT appears to be a thoroughly practicable gas turbine was worked out in Germany just before the war. A turbine furnishing about 200 horse·power was built at Hanover a few years back, and was run for three years in order that its faults might be ob served. Later on, 11 turbine furnishing 1,000 horse power and driving an electric generator was built at aJ;lother works in Germany. It was tested and an over all efficiency of 20 per cent was claimed between the energy delivered by the explosions and the electricity furnished by the generator. The special feature of the apparatus was that the explosions took place in one set of chambers, and the expansions partly in the ex plosion chambers and partly in the space in which the rotor of the turbine was revolving. The rotor of the turbine ran in a horizontal plane; a number of explosion chambers, ten in the 1,000 horse power apparatus, being arranged around its shaft. The explosion chambers were cast together with air and gas chambers, the whole forming approximately a trun cated cone, the electric generator being placed at the apex of the cone. The gas and air chambers were kept full at definite pressures. Each explosion chamber was first filled with air up to the pressure in the air reservoir; the air supply was then cut off and gas forced in also under pressure, preferably by successive strokes of the gas pump, so that the gas would form layers in the explosion chamber. (Concluded on page 334)