Page:Popular Science Monthly Volume 18.djvu/293

Rh looks not only to electricity to furnish light, and, through the medium of present unutilized natural resources, motive power, but heat as well. The exhaustion of fuel-supply will inevitably drive us to seek and find some other agency to do our work, and this, he thinks there is good reason to believe, will be found in electrical energy.

A New Smelting-Furnace.—The utilization of petroleum for fuel in the various metallurgical operations, in steam generating, and generally where coal is industrially used, has been a favorite project with inventors for a dozen years or more. The advantages of such a fuel are very great, and the reward to the successful inventor of an apparatus that would make its use practicable would be correspondingly large. Like gas, a liquid fuel is under perfect control, and is in a form allowing of perfect combustion if properly burned. The fuel is, moreover, very abundant, the production having been for some time past in considerable excess of the demand. In one district alone something like six thousand barrels are daily running to waste through lack of storage capacity, and one of the largest producers of oil is now obtaining from the wells about fifteen thousand barrels per day more than can be marketed. The oil companies, as well as inventors who have hoped to make a fortune by a successful furnace, have been unceasing in their efforts to turn this fuel to industrial uses, but so far the devices—and they have been many—have uniformly failed. A furnace is, however, now being developed which seems to promise, if not a complete solution, at least a partial solution of the problem. The furnace consists, in reality, in an immense blowpipe-flame, which is made to play upon the ore to be smelted, when used for metallurgical purposes, and to pass through boiler tubes when used for steam generating. In the metallurgical apparatus there is first a fuel-furnace in which any ordinary fuel may be used, or oil if preferred. Against the upper portion of the flame from this furnace a blast of air is projected, similar to that from the mouth blowpipe against the flame of a spirit-lamp. Into this blast, at the point where it strikes the fuel-furnace flame, a stream of oil is introduced. The on-going blast and the heat of the flame vaporize the oil, which is then in a condition to be completely consumed. The result of this arrangement is the production of a column of flame, some thirty or forty feet long, of high temperature. This flame is projected horizontally through an iron cylindrical shell, lined with fire-brick with a facing of graphite, into which the ore to be reduced is fed from a hopper at the farther end. The shell is slowly rotated, so that the entering ore, tumbling about, is brought into intimate contact with the flame. It is also slightly inclined, that the material may slowly feed into the flame, and the melted material run down into the crucible at the lower end, where it is tapped and the slag run off in the usual way. The farther end of the revolving cylinder is let into a chamber, built of brick, stone, or clay, which is divided into compartments by walls or sheets of incombustible material kept constantly wet by running water. The hot gases, carrying vapors of the metals and other ingredients of the ore, are here gradually cooled down and condensed, the character of the condensation depending upon the materials present in the ore. The burned gases are withdrawn from the condensing chamber by means of an exhaust-fan, and discharged into the atmosphere. The air and oil are both under perfect control, so that a heat suitable for smelting or for vaporizing can be produced at will. Several furnaces are shortly to be put into operation for the reduction of ores of the precious metals, on which experiments have so far chiefly been made. The inventor, however, expects to be able to use it successfully in making iron and steel, as well as in burning lime. A modified form is also suitable to the burning of pottery and glass-making. In using it for generating steam, the boiler flue is made large, the flame at no point coming in contact with the metal, thus avoiding the burning out of the boiler, the chief difficulty encountered by most of the other devices using oil-fuel for steam-making. The experiments with the furnace upon an industrial scale have been as yet too few and imperfect to thoroughly test its value, but they seem to warrant the opinion that the furnace has capabilities that promise very well for its future usefulness.