US299974A - Furnace - Google Patents

Description

(No' Model.)

L.P.'FRENCH.

' FURNAGE. v I No. 299,974: v Paten tedJune10,18'84. V

UNTTED grains PATENT @rrrcze,

LYMAN P. FRENCH, OF BOSTON, MASSACHUSETTS.

FURNACE.

M SPECIFICATION forming part of Letters Patent No. 299,974, dated June 10, 1884.

Application filed October 9.6, 1883: (No model.)

To aZZ whom, it may concern.-

Be it known that I, LYMAN P. FRENCH, of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Furnaces, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relating to furnaces is shown embodied in a locomotive fire-box or furnace having an inclined bridge-wall extending diagonally across the fire-box from its lower front end toward its rear upper end, the furnace also having a deflecting-wall depending from its crown-sheet in front of the upper edge of the bridgewall.

In another application for Letters Patent No. 95,125, filed May 16, 1883, I have shown and described a furnace having walls of this general arrangement, the bridgewall, however, being partly composed of a water-space or table which is necessarily a permanent part of the fire-box, and is very expensive.

The present invention consists in a novel construction of the bridge-wall, which is of masonry, and is made hollow for the intro duction of heated air.

Masonry walls for the introduction of air have usually been made of hollow bricks provided with numerous small perforations for the air to flow through; but such construction is very objectionable, as owing to the great difference in temperature of the different parts of the bricks they expand unequally and soon break or crumble, and furthermore the area of heatingsurface to which the air is exposed is reduced by the perforations.

Arches or walls for the introduction of air have also been made of fire-brick having a single large air passage or chamber within them, and of two layers of brick having corresponding grooves in their adjacent faces which constitute a seriesof tubular passages passing longitudinally through the wall. In this latter construction the main part of the two layers are in contact with one another, forming a solid mass of masonry. When the wall has a large space or chamber included within it, and the faces of the brick inclosing the said space are separated from one another and unequally exposed to the fire, as is usually the case, one

side, for example, being exposed directly to the fire, and the other protected therefrom by the intervening layer of air, the said faces of the brick will be unequally heated and the greater expansion of the one than of the other will produce severe internal strains, which will soon result in the destruction of the brick and arch constructed therefrom. These objections are obviated in the present invention by making the wall of two independent layers of bricks separated a sufficient distance to inclose between them an air space or chamber of the desired size, thesaid chamber opening at the'end of the wall directly into the firebox. The separation of the layers is preferably effected by providing them with laterallyprojecting flanges, which are turned upward in the lower layer and downward in the upper layer, the latterlying 011 the former. Each layer being quite thin but of uniform thickness throughout, will attain substantially uni form temperature throughout, and the two layers being disconnected from one another, the one next the fire, which will reach the highest temperature, is free to expand or crawl along the other without producing any strain, so that a wall or arch'constructed in this manner is very durable.

Figure 1 is a longitudinal section of a locomotive firc-box embodying this invention. Fig. 2 is a horizontal section thereof on line as as; Fig. 3, a perspective view of one of the bricks of which the arch or bridge-wall is composed.

The firebox a, grate b, and opening a, for the introduction of fuel, are all of usual construction, being as found in locomotives now in use. The said fire-box contains an arch or bridge-wall, e c, composed of two independent layers of firebrick, shown in this instance as supported on water-pipes 2', connected by suitable couplings with the sheets of the firebox. The lower layer, e, of brick rests direct- 1y on the said pipes, and the upper layer, 6', is supported a short distance above the lower layer, thus inclosing an air space or chamber between them, provided with inlet-passages on through the walls of the fire-box connecting with the external atmosphere and admitting air to the spaces between the two parts of the bridge-wall. As herein shown, the upper portion of the bridge-wall is supported above the lower portion, 6, by means of corresponding flanges, 6 on the two layers of brick,

and the upper edge of the air-chamber in the' ward and upward direction to a point a short tension over the door.

distance below the crown-sheet, and the firebox is also provided with a deflecting-wall, m, extending from the crown-sheet forward and downward toward the bridge-wall, the lower edge of the said deflecting-wall being in front of and below the level of the upper edge of the bridge-wall. In the said application, however, the bridge-wall was shown as having an extension reaching the rear sheet above the door, so that the products of combustion were compelled to pass through two passages, one at either side of the door. The said ex tension was intended to protect the fines from access of cold air when the door was opened for the introduction of fuel, and the claims of the said application cover, broadly, the combination of the bridgewall and deflecting-wall having the described arrangement with relationto one another, independently of the ex- It is often found to be more advantageous to afford a uniform passage for the products of combustion over the entire upper edge of the bridge-wall than to provide for the protection of the dues when the door is opened, and in the present application the upper edge of bridge-wall is substantially parallel with the crown-sheet, thereby affording a uniform passage for the products of combustion over the entire upper edge.

I do not in the present application broadly claim the combination of the bridge'wall and deflecting-wall, nor a bridgewall provided with an air-chamber.

I claim 1.. In a furnace, a bridge-wall or arch com= posed of two independentthin layers of unperforated fire-brick, each layer being of substantially uniform thickness throughout, and the layers being separated from between them, the said chamber communicating with the air outside of the furnace and opening at one end of the layers of brick into the furnace, substantially as described.

2. The bridge-wall inclined from the lower front wall of the fire-box rearwardly and up.- wardly, the said wall being composed of two independent layers of bricks, each layer being of substantially uniform thickness, and the two layers being separated by an air-space, which opens into the furnace at the upper edge of the wall and communicates with the air external to the furnace at the lower portion of the said wall, substantially as described.

3. The bridge-wall inclined from the lower front wall of the fire-box rearwardly and up wardly, the said wall being composed of two layers of bricks separated by an air-space which opens into the furnace at the upper edge of the wall and communicates with the air at the outside of the furnace at the lower portion of the said wall, combined with the deflecting-wall depending from the crownsheet in front of the upper edge of the said bridge-wall, the lower edge of the said deflect ing-wall being below the level of the upper edge of the said bridgewall, substantially as described.

4. Thebridge-wallextendingfromthelower front portion of the fire-box below the fines rearwardly and upwardly toward the crownsheet, the upper edge of the said wall being substantially parallel with the crown-sheet, combined with the deflecting-wall, depending from the crownsheet in an inclined forward and downward direction, and having itslower edge parallel with and below the level of the upper edge of the bridge-wall, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

LYMAN P. FRENCH.

\Vitnesses:

Jos. P. LIVERMORE, V. H. SIcs'roN.

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