US1758394A - Self-cooling furnace bottom - Google Patents

Description

May 13, 1930. F. P. FAIRCHILD v SELF COOLING FURNACE BOTTOM F iled Jan 5,

1926 3 Sheets-Sheet l N BY N I W May 13, 1930. F. P. FAIRCHILD SELF COOLING FURNACE BOTTOM Filed Jan 5, 1926 3 Sheets-Sheet 2 HUUUDE um wN i mvmjoze ATTORNEY May 13, 1930. F. P. FAIRCHILD SELF COOLING FURNACE BOTTOM Filed Jan. 5. 1926 5 Sheets-Sheet 3 Ell 74!; Vllfllllrlllllfrlfl nlfllllvlfllIl/lllll Wlliflflllfllllll all!!! A TTORNE Y Patented May 13, 1930- UNITED STATES PATENT OFFICER.

FREDERICK P. FAIRCHILD, 01 WHITE PLAINS, NEW YORK, ASSIGNOR T THE'ALLEN I SHERMAN EHOFF COMPANY, A CORPORATION OF PENNSYLVANIA SELF-COOLING FURNACE BOTTOM Application filed January 5, 1926. Serial No. 79,302.

This invention relates generally to fuel burningfurnaces and more particularly to bottoms for such furnaces which are exposed to high temperatures. It also relates to means for cooling such furnace bottoms and to means for subsequently utilizing the coolmg medium and the heat extracted by such medium from the furnace bottom.

The term furnace bottom or bottom is employed herein to designate the portion or portions of the Walls of a fuel burning furnace which are exposed to high temperatures and upon which may fall highly heated solids, such as incombustible residues resulting from the burning of fuel in the furnace.

When certain fuels, such as oil, gas or powdered coal are burned in a furnace high temperatures are often attained. Such fuels leave only a small amount of incombustible residue which is insuflicient in amount to afford the protection to the furnace bottom necessary for long life of the bottom. Moreover, this residue is frequently in the form of slag which gathers on the furnace bottom and flows down over the refractory lining causing breakage thereof and being generally harmful thereto. Accordingly, it is necessary to provide means for maintaining the temperature of the furnace bottom below certain maximum temperatures and desirable that such means be substantially automatic or self acting and comprising simple structure.

My. invention contemplates the construction ofa furnace bottom and supporting structures therefor which will be substantially self-cooling. To this end I provide passages in the furnace bottom through which cooling fluids may flow. I prefer that these passages should haveinlet and outlet openings near the lower and upper .ends of the furnace bottom and'should extend upward-' ly to permit the cooling fluid as heated to expand and rise therein, thus creating a current drawing in additional cooling fluid at a rate depending on the temperature of the wall and operating substantially automatically: My

invention also includes passages extending horizontally in the bottom and preferably communicating with the upper ends of the upright passages and so constructed, arranged and connected to associated parts as to insure flow of cooling fluid therethrough.

In the drawings showing one form of apparatus embodying my invention and attached to this specification and forming a part of this application- Fig. 1 is a top plan view, partly sectioned as on line 11 of Fig. 3, of one form of furnace bottom embodying my invention;

Fig. 2 is a vertical, longitudinal view, partly in section, taken on line 2-2 of Fig. 1;

Fig. 3 is a vertical, transverse view taken on line 33 of Fig. 1;

Fig. 4 is an enlarged, fragmentary, sectional view showing the construction of a portion In the drawings, 1 designates substantially parallel girders suitably mounted on piers or other foundations (not shown) and 2 designates a plurality, in this case three, substantially parallel girders of smaller dimensions extending across the space between the girders 1. Each of the girders 2 is suitably supported upon piers or other foundations (not shown) and at their ends may be joined to girders 1 as by riveting or otherwise.

The girders 1 and 2 carry oh their top surfaces the upright walls 3 of a fuel burning furnace. substantially rectangular in horizontal cross section. The girders 1 and 2 also support the furnace bottom as will hereinafter more clearly appear.

The girders 2 are arranged one at either end of the furnace bottom and under the end walls 3 of the furnace, and the remaining girder 2 extending between girders 1 midway between the end girders 2. In Figs. 2 and 3 this middle girder 2 is shown disposed between the pairs of hopper openings provided in the furnace bottom. Across the top of these three girders 2 and extending length- The furnace bottom is suspended from the girders 1, 2, and 4 and comprises a plurality of upwardly extending side walls and discharge openings in the lower portion of the bottom. Four discharge openings are shown, disposed one adjacent to each cornerof the bottom. These upwardly extending walls form four ash receiving hoppers each terminating in one of the discharge openings. The furnace bottom shown includes a plurality of angle bars 5 of various suitable lengths secured at their upper ends by brackets 6 or otherwise to the top flanges of the girders 1, 2 and 4 and carry at their lower ends gate frames 7 provided with suitable discharge openings 8 therethrough. Each gate frame 7 is equipped with a movable door 9, to which door is joined a door actuating connecting rodv 10 having a piston (not shown) mounted for reciprocation in a cylinder 11.

The depending angle-bars 5 are fitted with the necessary securing means, such as bolts and nuts, by which wall plates 12 may be secured to the inner side of the bars to constitute an outside metal shell for the furnace bottom. Each of the members 7 carries on its top a liner supporting member 13 provided with an opening l3 corresponding to and aligned with opening 8 of member 7. Adjacent to the members 18 and surrounding each opening 8 is also provided a plurality of members 14 which may be Wall plates having upstanding flanges 15. These members 14 are carried by the angle bars 5 and serve to position the liner members of the furnace bottom, with respect to the discharge openings 8.

The wall plates 12 and the members 13 and 14, as well as the girders 1, 2 and 4, are protected from the heat within the furnace by one or more layers of refractory material,

this material comprising in the illustrated disclosure a layer of units 16 in contact with wall plates 12 and two layers of units 17 at the inner side of units 16, the units 17 being composed preferably of refractory brick.

An inverted T-beam' 18 extends lengthwise of the furnace bottom and rests on spacers on the top of, and is parallel to, the I-beam4. This beam 18 carries on its upwardly ex tending web a plurality of arches 19, which are preferably castings of a length convenient to be readily handled. Similarly T- beams 20 are supported in inverted position on the middle cross girder 2 and extend from the outer side walls 3 inwardly but preferably not entirely across the furnace bottom. These T-beams 20 carry at their upper edges a plurality of arches 19. It will be understood that the beams 18 and 20, together with the arches 19 constitute means for supporting the lining units 17 which extend over the arches where two upwardly extending bottom walls intersect, that is, between each of the four hopper discharge openings 8 of the furnace bottom herein illustrated. The lining units 16 preferably consist of members having passages extending therethrough, for example hollow tile, the individual units being arranged with the passages 22 therethrough extending upwardly and aligned with the corresponding passages of other tile above and below so as to form passages which extend from the lower end of the furnace bottom upwardly within the walls of the furnace bottom near to the top thereof. Suitable inlet openings 21 through the wall plates 12 to the passages 22 within the blocks or tile 16 are provided at the lower ends of, the passages so that cooling fluid, for example air, may enter and pass upwardly through the passages. The outer walls of the furnace bottom adjacent to the girders 1 and 2 are preferably provided with outlet passages 23 from the passages 22 of blocks 16 which may extend over the tops of the girders 1 and 2 and between these girders and the walls 3 of the furnace. The passages 22 in the remaining walls of the furnace bottom extend to the spaces between the arches 19 and the T-beams 18 and 20, it being noted from the drawings that these members constitute horizontal passages extending from the middle of the furnace bottom to the sides and ends thereof. The T-beam 18 with its arches 19 provides two adjacent passages 24 extending lengthwise of the furnace bottom and communicating at each end with an upstanding pipe 25 fluid may enter through openings 21 at the T lower ends of the various passages 22 and flow upwardly through the passages and out into the horizontally arranged passages 24 and 26. It will also be understood that when the walls of the furnace bottom are heated the cooling fluid within the passages 22 will extract heat from the walls of the furnace bottom, thereby becoming heated, and as the temperature of the cooling fluid is increased it will tend to move upwardly within the passages, thereby creating a flow of cooling fluid through openings 21, passages 22 and horizontal passages 23, 24 and 26. The rate of movement of the cooling fluid in these passages will to a certain extent depend upon the temperature of the furnace bottom, the higher the temperature the greater being the rate of flow of cooling fluid through these passages. In this manner the furnace bottom becomes substantially self-cooling and will automatically maintain its temperature within certain limits. When airor gas is the cooling medium, practically no attention need be given to the cooling of the furnace bottom.

Although cooling fluid within the substantially horizontal passages 23, 24 and 26 would ordinarily tend to remain stationary, I insure a flow of cooling fluid through these horizontal passages largely by connecting the upwardly extending passages 22 with the horizontal passages. The temperature induced flow of the cooling medium upwardly Within the passages 22 induces a flow of cooling medium in the horizontal passages which flow may be further increased in any one of several ways. For example, in Figs. 1 and 2 I have illustrated upstanding pipes 25 connected to passages 24 which in themselves would tend' to create a flow of fluid in the passages 24. These pipes 25 may be provided with outlets to discharge the cooling medium, after it has extracted heat from the furnace bottom, into chambers or rooms which are to beheated; or they may be connected to the burners (not shown) of the furnace, when the cooling medium is air. The heated air is thus discharged directly into the furnace where, due to the slight vacuum maintained within the furnace or the suction of the fuel being forced into the furnace, or both, it will tend to create a circulation of air through the pipes 22 and 24.

In Fig. 5 I have shown the passages 22 of certain walls of the furnace bottom com municating with suitable passages 27 within the walls 3 of the furnace from which passages 27 one or more outlets 28 lead into "the interior of the furnace. Air or gas passing upwardly through passages 22 may thus be led directly into the furnace chamber and utilized in the combustion of the fuel therein. In Fig. 6 I have shown a slightly modified form in which a'manifold 29 is carried along the sides of the furnace bottom, for example by suitable supporting brackets 30 connected to the girders, this manifold communicating with a plurality of passages 23 for receiving air or gas therefrom and conducting the same to a burner (not shown) of the furnace or to other means in which the heated gas or air may be utilized. a

Having thus described my invention so that those skilled in the art may practice the same, what I desire to secure by Letters Patent is defined in what is claimed, it being understood that changes or alterations in the above described apparatus and not amount ing to invention may be made without de-' parting from the spirit of my invention.

\Vhat is claimed is: 1. A furnace bottom having two downwardly diverging walls, upwardly extending cooling-fluid passages therein, beams supporting the walls and positioned within the wardly extending cooling-fluid passages within all the said walls having inlet openings near their bottoms and outlet openings near theirupper ends, the outlet opening from the said passages inthe joined walls leading into the said horizontal passages.

3. In a hopper the combination with a plurality of spaced beams including an intermediate beam, of supporting bars secured to said beams and carrying hopper walls, said walls converging to form a plurality of bottom discharge openings,- a layer of hollow tile in each of said walls, said tile being laid j endito end in upwardly extending courses, and ventilating members disposed on said beams and connected with the upper ends of said courses of hollow tile, the lower ends of said courses having inlet openings therein. 1

4. A hopper comprising spaced supporting.

beams, wall supporting bars having their upper ends secured to said beams, walls supported on said bars and comprising a layer of hollow tile, said tile extending from the lower ends of the walls to the upper ends thereof, and ventilating members disposed on said beams connected with the upper ends of said tiles whereby flow of air is permitted through said walls and over said beams to prevent excessive heating 'of the walls and beams.

5. A hopper comprising spaced supporting beams, wall supporting bars having their upper ends secured to said beams, said bars being inclined downwardly from said beams, and a wall supported on said bars including a layer of hollow tile and an inner refractory lining, said tile extending from the lower to the upper end of the bars and communi- I eating with passages over the said supporting beams, said tile being laid end to end in courses extending lengthwise of the bars and forming closely spaced conduits for the flow of air therethrough.

6. A hopper comprising spaced support ing beams, gate frames, depending wall supporting bars secured at their upper ends to said beams and at their lower ends to said frames, transversely extending flanged plates laid side by side upon said bars with the flanges thereof resting upon said bars, a layer of hollow tile upon said plates, the tiles being laid end to end in upwardly extending passages in the walls for the flow of air therewardly extending passages having openings admitting atmospheric air to the lower ends thereof and the horizontally extending passages having outlets for the air at the outer ends thereof.

8. In a furnace bottom, two downwardly diverging walls, upwardlv extending fluid passages therein, inlet openings at the lower ends of said passages, horizontal passages within the apex formed by said walls into,

which the upper ends of the upwardly ex,

.tending passages open and outlet openings from said horizontal passages.

9. A furnace bottom for a steam boiler furnace having upwardly extending walls,

means carrying the walls in suspension therefrom, upwardly extending cooling fluid passages in the walls and disposed in cooling ,relation to the walls and to the beams, the passages having suitableinlet and outlet openings for the admission into and escape from the passages of fluid for cooling the said walls.

10. A self-cooling furnace bottom for a steam boiler furnace comprising upwardly extending walls having upwardly extending cooling fluid passages provided with inlet and outlet openings and through which passages cooling fluid will flow upon being heated, and horizontal wall supporting means for carrying said walls in suspension therefrom, the upper ends of the passages communicating with horizontally extending passages disposed in cooling relation to the said supporting means.

11. A hopper for a steam boiler furnace comprising a supporting shell, spacing means within the shell and carried thereby, and a refractory lining carried by said shell and spacing means, the spacing means forming upwardly extending cooling fluid passages having suitable inlet and outlet openings and being disposed between the shell and refractory lining.

12. A bottom for a steam boiler furnace comprising refractory walls exposed to the heat of combustion of fuel in the furnace and to contact with incombustible residues of combustion, asuspended metallic structure carrying the said refractory walls and means for maintaining the refractory walls below the fusing temperature of incombustible resi dues contacting therewith, said means in-

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