US459742A - Steam-boiler - Google Patents

Description

(No Model.)

'J. A. CALDWELL. STEAM BOILER.

No. 459,742. Patented Sept. 22, 1891.

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UNITED STATES PATENT OFFICE.

JOHN A. CALDWELL, OF BAY RIDGE, NEIV YORK.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 459,742, dated September 22, 1891.

Application filed July 24, 1890. $e1ialN0-359,847. (No model.)

T0 at whom it may concern:

Be it known that 1, JOHN A. CALDWELL, a citizen of Great Britain, residing at Bay Ridge, county of Kings, and State of New York, have invented a certain new and useful Improvement in Steam Boilers of the Form Known as VVater-Tu be Boilers; and I declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to improvements in sectional steam-boilers, in which- Figure 1 is a longitudinal side elevation showing the furnace-walls in section, and Fig. 2 is a front elevation of the same.

These improvements will become more ap parent after the following explanation.

In other sectional steam-boilers the headers A B C D are all united in one piece. The result is annoyance from breakage caused by the unequal expansion of the tubes. To cut this header into four pieces and nipple these together so as to make a continuous waterway from the tubes to the steam and water drum was an improvement over the solid one piece header, since instead of breaking it yields at the point of jointure.

Established practice has decided that the number of tubes one above the other shall be eight, (8,) and that the horizontal rows of 7 tubes shall not be placed immediately above each other, as I have shown them, but in a staggered position, so that the hot gases as they pass up through the spaces of one row shall encounter the tubes of the next row, so as to retard them somewhat and divert them hither and thither.

To cut the header into four pieces and join them by nipples and at the same time retain the staggering effect called for, headers or boxes containing three tubes, which were triangular in shape, or boxes containing four tubes which were rhomboidal in shape, or, if five tubes were put in a box, the shape became like an hour-glass, &c. The reason that not less than three tubes to one box were used was because room had to be allowed to work a ratchet-expander from the opening in front with which to expand the nipples into place. The objection to three tubes in a box arranged in a staggered position is that the water from twelve tubes has to pass through one nipple where it connectsto the steam and Water drum, there being only room for one nipple in the small end of the triangle. With the rhomboid, containing four tubes to a box, the case is worse, for the water from sixteen tubes must go through the nipple connecting to the drum. While the top and bottom sides of the rhomboid are long enough to allow for two nipples, the fact that they have to stand past each other to give the stagger to the tubes, as already explained, made it impossible heretofore to put in more than one nipple of equal diameter with the tubes, and to make thenipple larger than four inches diameter, so as to increase the area of the water way, would require a special costly tube-expander to go with each boiler, while four-inch tubes and four-inch expanders are regular market sizes.

My improvements will now be plain. By placing the rows of tubes above each other and not staggering I secure boxes or headers of quadrangular shape, which stand exactly over each other. Hence there is room for two nipples of the regular commercial size, which secures a regular-sized nipple entering the drum for each eight tubes instead of each twelve or sixteen tubes, as in the cases explained above; and to retain the staggering effect and baffle or retard the hot gases, I place pieces of fire-brick or other material between substantially each alternate row of tubes, thus getting free circulation, a staggered direction to the gases, and a flexible header all in one boiler. This has not been accomplished before. Incidentally I gain very free access to the tubes by the unscrewing of four nuts and a better adjustment of bolts for holding on the header-covers.

In this class of boiler the fuel is burned 011 the grate E, the hot gases pass upward among the tubes, (which are surrounded by brick walls in the usual way,) then downward through the space F and upward again through the space H and out to the chimney. The water within the tubes circulates from the lower portion of the tubes toward the higher, thence to the steam and Water drum, along the drum to the back end and down the tubes I, there being one for each vertical row of tubes. All the boxes or headers are nippled to each other by the nipples J J J J, and to the drum by the nipples K. The tubes I are practically long nipples connecting the header D to the drum in the same Way as the short nipples .T J connect the headers -L to the drum in front.

I do not confine myself to the special shape of fire-brick or other material shown between the tubes. It may be shaped like a common brick, placed with the corner down, and enough of them placed on end to make whatever length is necessary; or a single thin plate of material may be placed on top long enough to reach from tube to tube. I do not confine myself to solid material, but it may be perforated, as shown at N, to allow the gases to partially pass through the obstructed space; or the sides of the bricks may be corrugated or notched, as at P, so as not to bear upon the tubes their whole length.

Having fully described my inventiomwhat I claim, and desire to secure by Letters Patent, is-

In a water-tube boiler, the combination, with a series of tubes arranged quadrangularly to each other, the sides of said quadrangles being arranged in horizontal and V61" tical planes, of fire-brick or other material disposed so as to bridge the space between substantially each alternate pair of said tubes for the purpose of giving a staggering direction to the hot gases.

I11 Witness whereof I have hereunto subscribed my name in presence of two subscribing witnesses.

JOHN A. CALDWELL.

\Vitnesses:

ROBERT I-IUTcPnNsoN, S. P. HU'rcHINsoN.

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