OFFICE OF SOCIAL UNCTION |
| DIRECTOR Abimbola Stacey |
ABOUT
In addition to the tubular flues just mentioned, there is a broad and sufficiently copious flue, situated beneath the cylindrical boilers, by means of which the heated air, &c. is brought into contact with the entire lower half, or exterior, of all the cylindrical boilers.
The very extensive boiler surface thus acquired and presented to the action of the heat, contributes to render the production of steam exceedingly copious, while the heat imparted by the fuel is almost entirely absorbed in its production. Such is the efficiency of this arrangement, that in a boiler nine feet and eight inches long, with two cylindrical boilers, each twenty inches in diameter, embraced within that length, the whole weighing, inclusive of all the flues, three thousand pounds, two hundred gallons of water have been evaporated in an hour, under a pressure of ninety pounds to the square inch, and at the expense of two bushels of anthracite coal.
In order to facilitate the combustion, or rather the ignition of the coal, a slip-chimney has been introduced into the engine, by means of which the height of the chimney may be varied at pleasure, from fourteen to twenty feet.
Among the advantages expected to result from this method of constructing boilers, are the exposure of a much larger comparative surface to the action of the heat; a very great reduction of the quantity, or weight, of the water necessary to a minimum supply in the boilers; a similar reduction in the weight of the boilers, as also in the thickness of the metal of which they are composed; together with certain facilities hereafter to be noticed, for removing, renewing, and replacing the boilers, without deranging other parts of the engine.
2d. The steam is employed in the working cylinders in such a manner as will allow of its operating, not only by its absolute, but by its expansive force. This object is effected by means of certain adjustments in the steam-valve apparatus, by the aid of which the entrance of the steam into each of the working cylinders is intercepted, at about five-eighths of the stroke of the piston. The advantages of such an arrangement are too obvious to require a particular designation. It is sufficient to remark, that by this means, three-fifths of the steam generated, are rendered quite as efficient as the whole would be without such an arrangement.
3d. The adoption of wooden wheels, bound with wrought iron, and of such a construction as will admit of tightening the tire, or otherwise repairing it, without materially affecting the relations between the centres and peripheries of the wheels.
It is obvious to any one acquainted with the nature of the materials employed in the construction of wheels, that the iron bands, or tires, of wooden wheels, will expand and contract by the ordinary changes in the temperature of any climate, in such a manner, and to such an extent, as will, sooner or later, render the tire loose upon the fellies. In the wheels of the Pennsylvania locomoter, such a defect is readily remedied by withdrawing the flange-tire and inserting thin iron wedges between the remaining tire and the fellies, without the hazard of producing eccentricity in the wheel.
4th. The construction and application of boxes or bearings for the wheels, or between the carriage frame and the axles, which not only serve as steps for the bearing journals of the axles, but as receptacles for the grease, oil, or unguent, necessary for their lubrication.