US1776906A - Furnace - Google Patents

Description

Sept. 30, 1930. J. c. HoBBs 41,776,906

FURNAcE v original Filed sept. 21, 1925 2 sheets-sheet 1 Elig- L mfc/44% Sept. 3o, 1930.

J. HoBBs v .FURNACE original Filed sept.l 21, 1925 2v Sheets-sheet 2 INVEN'ToR ToeNEYs Patented Sept. 30, 1930 PATENT oFFlcE JAMES c. HoBBs, or PAINESVILLE, oHIo -FURNACE Application filed September 21, 1925, Serial No. 57,498. i Renewed December 3, 1929.

My present invention relates to improvements in furnaces, particularly furnaces in which the combustion chamber is cooled by a circulating medium, and will be best understood from the following description and the annexed drawings, in which Fig. l is a sectional side elevation of a steam boiler and its furnace which I have chosen for purposes of illustration of my invention; Fig. 2 is an en? 1'0 largcd View of a portion of the sidewall in Fig. l; Fig. 3 is a section on the line 3-3 of Fig. 2, and Fig. 4 is a view` similar to Fig. 3 but showin a modification Like re erence characters indicate like parts in the several views In the illustrative form, a furnace chamber 10 is provided with a front wall 11, a rear wall 12 and side Walls 13, the fuel entering the furnace chamber through a powdered fuel burner 14 being projected downward and the burner gases passing fromthence upward across the water tubes 15 of the steam boiler illustrated as being used in connection with my novel furnace.

Extending across the furnace chamber is a row of slag-screen tubes 16 of a known form connected at their lower ends to a header 17 and at their upper ends to a` header 18. From the header 18 extends upwardly a row of tubes 19 disposed inthe rear wall 12 in the manner to be described more in detail hereinafter, the upper ends of the tubes 19 connecting to inclined headers 20, the upper ends of which are connected through pipes 21 and tubes 22 with the steam and water drum 23. The header 17 is connected by pipes 24 and tubes 25 with the' drum 23. The arrangement just de- Iscribed provides a water circulation through the tubes 16 and upwardly through the tubes In the illustrative embodiment, an upper header 26 and a lower header 27 are connected at their opposite ends-by downcomers 28 and 29 located outside of the wall 13 and by bent tubes 3() arranged in the side wall in a manner to be described more in detail hereinafter. The lower header 27 is connected by a pipe 31 with the pipe 24 and the upper end of the upper header 26 is connected by a pipe 32` and tubes 33 with thesteam and water drum 23. By this arrangement a local circu-l lation is maintained in the side wall cooling tubes30 by water received from and returning to the drum 23. This tube arrangement, however, is no part of my present invention and the side wall cooling tubes 30 may also be connected in any other suitable manner with a source of cooling water.

The tube arrangement in each of the side walls 13 as well as in the rear wall 12, in the 60 :illustrative embodiment, is substantially the same, and a description of one of these walls will be sufficient.

In Figs. 2 and 3 is shown a verticaland a horizontal section of a portion of one of the side walls 13, in Wliichthe tubes 3 0 are bent so as to project inward through the wall from the headers 26 and 27 and then ydownward 2 parallel to the face of the walland preferably ,adjacent the front face of the-wall but inside of such face. In the illustrative form, the wall above and below the ends of the tubes 3U is made up of the ordinary masonary refractory with a space at the upper part where the vupper, end of the tube 30 passes through the 75 wall to permit the tube 30 and the connecting downcomers 28 and 29 toexpandwithout destroying the wall.

The furnace wall is made up of a plurality Y of fixed channels 34 extending'horizontally, 80 the space between the channels beinglilled by the usual closures 35. lConnected to the fixed members 34 is a plurality of spaced vertical I-bcams 36. Preferably I make the wall through which the tubes 30 pass, of a' 85 plurality of courses fof special tile, arranged preferably not only'so as to provide grooves or recesses for the tubes 30, but also so that the tile may be held from inward movement. while permitting free expansion thereof horizontally and vertically. In the arrangement shown in Figs. 2 'and 3, the courses are made 11p of-pairs of tile 37 and 38, 37 and 38, etcz; arranged so that the adjacent faces' of each" pair are behind a tube 30, this space being widened out to provide the recessgor groove for the-tube. Preferably in laying upthe lwall, I also provide an open space between the adjacent faces of each pair of tile in`each course, as, for instance, between tile 37El and 19 less immaterial, because the heat can be prevented from doing any harm by the layer of insulating material 39. Furthermore, this space will eventually become filled with slag and prevent the radiant heat from passing between the tile. In the case of the space between the tile of each pair, as 37 and 38a for example, the passage of heat through the space is obstructed by the tube 30 in front of such space, this tube 30 being an effective means for preventing the passage of radiant heat through the space and to the metallic member at the rear of the space. The tube 30 also prevents slag from accumula-ting in the space, which in a short time would interfere with the action of the expansion joint.

lVhere tilel or brickwork is laid loosely at the sides of a furnace to allow for expansion, the slag will often fill up the spaces between the tile or brickwork in such a way that the wall becomes cemented together into a solid mass and, on cooling, cracks will be formed as the walls shrink. By protecting the joints by means of the tubes 30, the wall can contract after it expands and there will be no danger of cracking the wall.

The specific form for holding the tile in place which I have illustrated, comprises a T-header member 40 having hooked members at each lside engaging the flanges of the I-beam 36 freely, so as to slide up and down thereon, the T-head of the member 40 engaging a T-shaped groove 41 in a recess in the outer side of the wall, this recess being formed preferably partly in the adjacent faces of a pair of tile 37, 38. Preferably the groove 41 does not extend substantially below the horizontal center line of the tile, so that as the several courses of tile are built up resting on each other, the members 40 may be arranged in position and slid down into place in the recess 41 before the next course of tile is applied, the bottom of the recess 4l locating the member 40 at approximately the center 0f the tile.

Preferably I arrange the contacting faces of the tile in the successive courses so that they are non-planer. This is done so that if spaces should open between the tile, the radiant heat would not pass through such space.

It will be observed that the arrangement which I have described produces a wall in which the cooling tubes are sufficiently inside of the interior of the wall so as to efficiently cool such wall, while, at the same time enabling the maintenance of a furnace ternperature which is high enough to give a good eiiiciency. In order to increase this efficiency, I preferably fill the recesses or grooves containing the tubes 30 with a coherent mass 42 of refractory, after the wall is built and the tubes 3() installed. Preferably I use for this purpose ash slag of the same general character that is produced in powdered fuel furnaces.. Such ash slag may be put in place in any desired manner, as, for instance, by means of an air gun. The masswill adhere sufficiently to the tube and the adjacent tile to hold itself in place and, at the same time, will not prevent the horizontal relative motion of the tile 37 and 38, if such motion is produced by variations in temperature.

In operation, particularly where ash slag is used for the mass, if the refractory tile 37 and 38 have their front faces worn or burned away, the refractory mass 42 will also be gradually removed until there comes a point where the heat abstracted through the tubes 30 will balance the heat passing into the fur? nace wall so as to prevent further destruction of the wall. At the same time, the slag deposited on the wall will serve as a further insulator to protect the wall. `While, for some purposes, the tubes 30 may be placed in position and their recesses in the wall permitted gradually to fill up with slag, I f ind it preferable to fill such spaces with slag before beginning operation, so that, first, a greater layer of slag may be interposed between the tubes 30 and the interior of the furnace and, second, to insure a more positive`construetion than would be had if dependence were placed on the depositionof slag from the furnace.

In Fig. 4, an arrangement is shown in which the wall, instead of being made up of courses of special tile surrounding the tubes 30, is made up of refractory brick, so as to provide recesses for the tubes 30 and the recesses thus formed are filled with a refractory mass 42 which preferabl is of ash slag applied in the manner described above. In a wall of this construction, the wall is retained in a vertical position by the tubes 30 on one side and the I-beams 36 on the other.

It will be understood that the arrangements whichI have described are merely i1- lustrative and that the embodiment of my invention may be widely varied.

I claim:

1. In a furnace, a combustion chamber having a vertically disposed wall composed in part at least of tile arranged in horizontal courses with open spaces between the tile of a course, metallic 'holding members in line with some of said spaces and engaging the tile to vprevent inward movement of the tile, each space in line with a metallic member heilig `widened at its inner end to form a tube recess, and a cooling tube in said recess to prevent the passage of radiant heat through the space to said metallic member.

2. n a furnace, a combustion chamber having a vertically disposed Wall composed in iti part at least of-tile arranged in horizontal courses with open spaces between the tile of a course, metallic holding members `in line With some of said spaces and engaging the tile to prevent inward movement of the tile, each space in line with a metallic memberbeing widened at its inner end to form a tube recess, a cooling tube in said recess to prevent the' passage of radiant heat -through the space to said metallic member, and-al coherent mass of refractory material in each recess between the tube thereinandthe combustion chamber.

3. In a furnace, a combustion chamber having a vertically disposed wall having courses of tile therein, fixed members outside the tile, said tile having uvertical T-shaped recesses in their outer faces open at the top of each course and closed at the'bottom, and holding members connected to said fixed members and free io slide vertically thereon and having T-heads in said 7l" -shaped recesses.

4. ln a furnace, a combustion chamber having a vertically disposed wall having courses of tile therein, fixed members having vertical flanges outside the tile, at least some yof said tile having vertical T-shaped recesses in their outer faces open at the top of each course and closed at the bottom, and holding members engaging said fianges and free to slide vertically thereon and having! T- heads in said T-s'ha'ped recesses.

Uli

5. In a. furnace, a combustion chamber having a wall with courses of tile therein, fixed members outside the tile, cooling tubes inrecesses in the inner face of the tile, and connectinglmembers between at least some of the tile and said fixed members and arranged to permit movement of the tile in a direction parallel to the cooling tubes while holding the tile against movement-at right angles to the plane of the Wall.

6. ln a furnace, a combustion chamber having a wall `with courses of tile therein, fixed beams outside of tile, at least some of said tile being recessed on the side adjacent said lbeams., cooling tubes in recesses in the innerface of the tile and extending arallel to said beams, and connecting mem ers engaging said beams and the recesses in said tile adjacent the beams and arranged to permitlthe tile to move parallel to saidbeams and said tubes while holding the tile against `innovement at right angles to the plane of the wall.

7. lin a furnace, a combustion chamber having a vertically disposed refractory' wall with a plurality of grooves -in the inner 'face thereo an open joint in said wall extending from each groove to the outer face of the wall, a cooling-tube in each of said grooves, and a coherent mass of refractory material` in each,

j groove between the tube therein andthe combustion chamber, said mass' of refractory be-. ing non-homogenous with the refractory wall.

8.v lin a furnace, a combustion chamber having a vertically disposed refractory wall with a plurality of grooves in the inner face thereof, an open joint in said wall extending from .each groove to the outer face of the wall, a coolingA tube in each of said groves, and a coherent mass of ash slag in each groove between the tube therein and the combustion chamber. 9. A furnace wall having at least a portion thereof formed of tile arranged in horizontal courses and provided with vertical re-` cesses having cooling tubes therein, and means other than the tubes for holding said tile against inward movement, while permitting vertical expansion thereof.

10. A furnace wall having at least a portion thereof formed of tile arranged in horizontal courses and provided with vertical recesses havingv cooling tubes therein, and

means other than the tubes'for holding said tile against inward or outward movement, while permitting vertical and horizontal expansion thereof.

l1. A furnace wall of tile laid in horizontal courses,`said wall having vertical expansion joints, cooling tubes between said joints and the furnace in position to protect said joints, a second set of vertical expansion joints alternately placed with respect to the .joints .of the first mentioned set, said wall being so proportioned that after it becomes cemented` together on the furnace side by means of slag, it will part at the joints which are protected by the cooling tubes and will not crack in the body` of the wall.

JAMES C. HOBBS.

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