US736693A - Fire-box sheet. - Google Patents

Description

No. 736,693. PATENTBD AUG. 18, 1903'. J. CONROY.

FIRE BOX SHEET.

APPLICATION FILED JAN 15, 1901. N0 MODEL.

JZ WQWWM I FER g v rates Patented August 18, 1903.

FIRE-BOX SHEET.

SPECIFICATION forming part of Letters Patent No. 73 6,693, dated August 18, 1903.

Application filed January 15,1901.

TO (1.56 lull/0m it may concern.-

Be it known that I, JAMES CONROY, residing at Salt Lake City, in the county of Salt Lake and State of Utah, have invented certain useful Improvements in Fire-Box Sheets for L0- comotive and other Steam Boilers; and I do hereby declare that the following is a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to a fire-box sheet for locomotive and other steam boilers.

The object of my invention is to provide a fire-box sheet so arranged that the sheet in expanding under heat and pressure will pinch the stay-bolts, so as to insure a tighter fitting the greater the heat and pressure.

In the accompanying drawings I have shown in Figure 1 a broken central sectional view of a portion of a fire-box sheet embodying my invention. Fig. 2 shows a central sectional view with portions removed on lines a: a; in Fig. 3. Fig. 3 shows a front view of a broken portion of a fire-box sheet embodying my invention, while Fig. 4 shows a sectional view with portions broken away on line Y Y, Fig. 3.

All those familiar with this art of course understand as usually constructed the staybolts, especially in the fire-box sheet of locomotives, become leaky under the tension and strain incident to the operation of the boiler.

As ordinarily constructed the fire-box sheet under strain is adapted to work away from the stay-bolts, so that in a short time a watertight connection between the bolt and sheet is a thing of the past. In my invention I overcome and prevent leakage by way of the stay-bolt openings in so embossing the plate and finally so positioning the stay-bolts within the embossed plates that as the sheet expands it is made to bind tighter and tighter against the stay-bolts. In carrying out this aim I provide the fire-box sheet B with a plurality of dished indentations, or what are known in the art bumplets. These indentations are preferably circular and are placed in series, preferably in a straight line, as is shown in Fig. 1, in which I have shown (No model.)

a number of dished indentations 1 1, which project in one direction and are upon that side of the sheet which comes outside or adjacent the fire. The next series of indentations 2 are pressed or upset in an opposite direction, asis shown in Fig. 2, for instance, these indentations coining upon the inside of the boiler, the next series in turn again being dished or set outward, and so on.- Now where the stay-bolts are secured to the sheet the openings for the same are placed within those indentations which are outwardly bulged, these indentations being threaded and being adapted to receive the stay-bolt C, as is shown more particularly in Fig. 1, where A represents the opposite side of the boiler. From this it will be understood that I provide a fire-box sheet provided with a plurality of bumplets or indentations alternately extending in 0pposite directions. Now as the steam-pressure and heat raise the area of the plate 13 there is a tendency of this plate B to buckle, and this buckling will be outward against the heads 3 of the stay-bolt O, which are secured within the outwardly-bulged bumplets 1. This pressure would be inward as much as outward if it were not for the steam-pressure within the boiler, which exerts a lateral force to drive the expanding fire-box plates out ward. Now as the plate expands it acts in the form of a multiplicity of levers of the first order, each system of levers finding a fulcrum at one of the stay-bolt heads, so that the metal surrounding these stay-bolt heads is forced under great pressure against the same, so that the greater the pressure or, in other words, the greater the'expansion of the metal between two stay-bolts the tighter will the stay-bolt heads be pinched within the sheet.

In referring to Fig. 2, for instance, were the stay-bolt heads placed within the bumplets or indentations 2 2 the plate as it expanded would be forced away from the boltheads, and so the greater the pressure within the boiler the greater the likelihood of a leak between the bolt-head and the plate, which in its normal condition was continually working away from the bolt-head, so that it would only be a question of time before there would be a leakage. From this it will be noticed that it is essential to set the bolt-heads within the outwardly-dished bumplets in order to bring about the desired result.

While my invention is especially adapted to be used in connection with fire-box sheets for locomotives, I do not Wish to be understood as confining myself exclusively to sheets for this class of boilers, as the same may be used in connection with any other class of boilers where stay-bolts are used under simi- IO lar conditions.

Having thus described my said invention,

what-I claim as new, and desire to secure by United States Letters Patent, is-

A fire-box sheet, provided with a plurality of inwardly and outwardly extending dished indentations, all of said outwardly-dished indentations being perforated and threaded as set forth.

JAMES CONROY. In presence of WM. R. HALL, C. M. DUNLOP.

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