US142273A - Improvement in steam-boilers - Google Patents

Description

T. w; PRATT.

Steam-Boilers.

N0. 142,273. Patented August26,l873'.

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AM. PHUTDLIT/IOERAFl/IC .00. M Y. (osaanmz's Pkacsss) vertical flues.

UNITED STATES PATENT @FFIGE.

THOMAS W. PRATT, OF BOSTON, MASSACHUSETTS.

- IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of Letters Patent No. 142,273, dated August 26, 1873; application filed July 11, 1873.

To all whom it may concern:

Be it known that I, T. WILLIS PRATT, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Steam-Boilers of which the following is a full, clear, and exact description, reference beinghad to the accompanying drawin gs making part of this specification, in which--- Figure 1 is a side elevation of a steam-boiler made in accordance with my invention. Fig. 2 is a front elevation of the same. Fig. 3 is a vertical section on the line as m of Fig. 2.

The most common forms of steam boilers now in use are, the locomotive-boiler, with horizontal flues, and the cylindrical boiler, with Many marine boilers are made like the locomotive-boiler, and many with both horizontal fire flues, combined with vertical water-tubes; but it is believed that all have some horizontal surfaces, where sediment will lodge, or narrow vertical water-legs, which easily become clogged, or angular, flat, or level spaces in the fire-tubes, where ashes will collect.

The chief requisites of a perfect steam-generator may be enumerated as follows: First, it should be simple and easy of construction,

\ so as to afford the greatest facility for repairs. Second, the furnace should be inclosed within the shell of the boiler, to economize heat. Third, the arrangement of the flues should be such as to induce the most rapid circulation, and, at the same time, assist the draft. Fourth, ample space should be afforded for water and steam, and a large water surface, from which the steamcan rise. Fifth,

the interior spaces should be so arranged as to allow all foreign matter heavier than water to settle freely to the lowestpoint, from whence the blow-oft cock can easily discharge them. Sixth, that the steam should be superheated. Seventh, that the flues should, without difficulty, be kept free from ashes or other deposits. My invention has for its object to embrace all of the requisites above mentioned; and consists in a cylindrical boiler placed in an inclined position, at an angle of from about thirty-five (35) degrees to about fifty-five (55) degrees with the horizon, and provided with a furnace-space at its lower end, situated under the upper portion of the water-leg, whereby all sediment in the water will be caused to slip or slide downthe surface of the lower tubesheet into the water-leg, from the lower angle of which it may be drawn out through ablowoff cock, instead of being deposited thereon, and preventing the direct contact of the water with the tube or crown sheet, which would soon be destroyed by the action of the fire; While the ashes and cinders will readily slide down the tubes, which are thus prevented from being obstructed, as is the case in horizontal boilers.

To enable others skilled in the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawings, A is a boiler of cylindrical form, placed at an inclination of about fifty degrees with the horizon, and provided with a series of tubes or flues, a, extending between the upper and lower tube-sheets b c, and inclined at the same angle as the sides of the boiler, these tubes being arranged in rows, one directly over another, so as to allow of the direct ascent of the heated water, while ample space is left between the tubes and the shell of the boiler for the cooler water to descend. The lower end of the boiler terminates in a circular waterleg, d, at the lowest point of which -is placed a blow-off cock, 0, through which all sediment deposited is drawn off.

To the front of the water-leg is fitted a firefront, h, forming the front of the furnace B. This fire-front is lined with fire brick, and is provided with an opening, 1', at its center for i the admission of fuel, said opening to be closed by a door, (not shown,) by which construction the necessity of cutting a door Way through the water-leg is avoided, the inclination of the boiler being sufficient to afford room for a door underneath the upper portion of the water-leg.

The shell or outer casing of the boiler should be made large enough to afford all the steam and water space commensurate with the amount of grate and fire surface without employing a dome or steam-chimney.

As the upper portion of the tubes pass through the steam-space is, situated above the water-line w w, the requisite amount of superv heating can be obtained.

From the foregoingit will be seen that, when my inclined cylin .lrical boiler is used, any sediment in the water will come in contact with the inclined surfaces of the tubes at, that of the bottom yy of the inside of the boiler, and that of the lower tube-sheet c,- and, instead of remaining or permanently lodging thereon, it will slide or slipdown these surfaces to the lowest point of the water-leg d, from which it is drawn 0% by the cock e, thereby preventing the crown or tube sheet being burned,incident to the employment of a vertical'cylindrical boiler. The ashes and cinders, also, are prevented from accumulating in the flues of my inclined boiler, as they slide back down into the fire, or are carried away through the smokepipe; consequently the flue-passages are not contracted, as in the case of the horizontal cylindrical boiler.

THOMAS WILLIS PRATT. In presence of- N. W. STEARNS. W. J. CAMBRIDGE.

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