US2409072A - Ignition furnace - Google Patents

Description

Oct. 8, 1946. E. w. SHALLOCK IGNITION FURNACE Filed Aug. 26, 194:5 2 Sheets-Sheet 1 INVENTOR. I i

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IGNITION FURNACE Filed Aug. 26 1943 2 Sheets-Sheet 2 INVEN TOR.

Edward 71/ 5/za/ZO0Z,

BY M m, 4 Q w r2 Patented Get. 8, 1946 IGNITION FURNACE Edward W. Shallock, Chicago, 111., assignor to American Ore Reclamation Company, Chicago, 111., a corporation of New York Application August 26, 1943, Serial No. 500,075

8 Claims. (01. 266-21) This invention relates to ignition means, and has to do with an ignition furnace for use with sintering machines.

The ignition furnace of my invention is particularly suitable for use with sintering machines of the continuous type, in which a train of pallets disposed in endwise contact are propelled along the upper run of an endless track, where they are charged or loaded with a layer or bed of the material or materials to be sintered, the charged pallets then passing successively beneath an ignition furnace which ignites the bed of material at the upper face thereof, after which the pallets pass over wind boxes by means of which air is drawn downward through the bed of material, causing clown combustion therethrough for effecting the sintering operation. After the sintering operation has been completed, the pallets pass about a return bend at the discharge end of the machine, where the sintered material is discharged, after which the pallets pass on to the lower run of the track and travel therealong to the return bend at the feed end of the machine, where they are elevated to the upper run and again charged, for repeating the operation. the type referred to are well known and need not be described here in greater detail.

Ignition furnaces commonly used in sintering machines of the type above referred to commonly comprise an elongated head or retort, as it is termed, having a lengthwise slot through which a combustible gas is discharged into a downwardly opening hood formed of refractory material, firebrick commonly being terior length of which corresponds approximately with the interior width of the pallet transversely of the machine, so that the upper face of the bed of material is subjected throughout substantially its full width to the action of the flame of the burning gas within the hood. The gas is mixed with air in proper proportion to produce an intensely hot flame, assuring ignition of the bed of material at the upper face thereof throughout its full width. It is necessary, to assure proper ignition of the material, that the lower face of the hood be placed in proximity to the upper face of the bed of material, so as to prevent objectionable cooling by excessive cold air being drawn between the hood and the bed of material. As soon as the upper face of the bed of material is ignited, combustion thereof occurs by down draft, such combustion being rather rapid at the upper portion of the bed used. The gas is ignited within the hood, the in- ,25 Continuous sintering machines of and resulting in the generation of intense heat. The lower portion of the refractory hood is thus subjected to intense heat, particularly at its lower face, by the burning gas within the hood and by the heat radiated from the bnrning bed of material. That results in the lower portion of the hood being quickly burned away so that it soon assumes an uneven or ragged condition, and the space between the lower face of the hood and the upper face of the bed of material is enlarged to an objectionable extent. That is objectionable for two reasonsthe uneven or ragged condition of the lower face of the hood renders it difficult to obtain uniform ignition of the bed of material at the upper face thereof, with the result that unifornnsintering is difiicult to obtain, and, in addition, the enlargement of the space between the lower face of the hood and the bed of material permits entry therebetween of an objectionable amount of cold air, which renders it difficult, in extreme cases, to ignite the bed of material. In order to reduce the objectionable effects of the burning away of the lower portion of the hood, it is necessary frequently to renew the structure or firebricks of the hood. That is objectionable from the standpoint of expense, but is even more objectionable in that it necessitates shutting down the machine while the hood is being renewed, with resulting serious loss in production.

My invention is directed to providing an ignition furnace which avoids the above referred to objections to the ignition furnaces at present in use. More specifically, I provide an ignition furnace in which the hood portion comprises firebricks so supported as to be removed and replaced with expedition and facility, these bricks being effectively cooled at the lower portions thereof in a manner to prevent, or materially reduce, disintegration or burning away of the bricks at their lower portions y the intense heat to which they are subjected. I accomplish that result by supporting the firebricks of the hood on water conduits or pipes through which cooling water is circulated, so that the bricks, particularly the lower portions thereof, are effectively cooled in a, manner to prevent objectionable heating and burning of such lower portions. In addition, the fire bricks are so mounted on the pipe supporting frame as to be readily removed and replaced thereon individually, so that selected ones of the bricks may be removed and replaced without disturbing the other bricks or the remainder of the hood structure. Further 3 objects and advantages of my invention will appear from the detail description.

In the drawings:

Figure l is a side view of an ignition furnace embodying my invention, applied to a continuous type of sintering machine of known construction and operation, above referred to, the sintering machine being shown fragmentarily in transverse section and one of the pallets being shown in section, certain parts of the machine being omitted for clearness of illustration;

Figure 2 is a plan View of the ignition furnace and the adjacent portions of the sintering machine of Figure 1;

Figure 3 is a central vertical sectional view of the ignition furnace taken substantially on line 33 of Figure 1;

Figure 4 is an end view of the ignition furnace taken substantially on line 44 of Figure 1- of the of the Figure 5 is an isometric View of one firebricks used at the sides of the hood ignition furnace; and

Figure 6 is an isometric view of one of the firebricks used at the ends of the hood of the ignition furnace.

I have illustrated the ignition furnace of my invention as applied to a continuous type of sintering machine. This machine is of known construction and operation, described above; and a brief description thereof will suffice here. The machine comprises a suitable frame I!) carrying an endless track upon which wheel-mounted pallets |2 travel. The pallets may be of any suitable known construction, but preferably are constructed similarly to the pallet, including the grate, disclosed in my Patent No. 1,722,344. The pallets l2, one of which is shown in the drawings, receive a charge, in the form of a thick layer or bed |3, of the material, or mixture of materials, to be sintered. After being charged, the pallets pass beneath the ignition furnace, as previously explained, at which time the pallet beneath the furnace is positioned above a wind box I4 through which air is drawn downward through the bed l3 for causing, in conjunction with the ignition furnace, ignition of the upper face of the bed, the pallet in its continued travel along the upper run of the track passing over successive wind boxes effective for drawing air downward through the bed l3 and causing downward combustion therein and resulting sintering of the bed of material. The construction and operation of the machine, as above briefly described, are well known and understood by those familiar with the sintering art, and further description of the machine is thought to be unnecessary except with respect to the ignition furnace, 'constituting my instant invention.

The ignition furnace of my invention comprises a retort I5 having a head |6 of generally elongated rectangular shape in plan provided, at its midlength, with an upwardly extending neck I! having at its upper end an annular bolting flange i8. Flange H3 is bolted to a corresponding flange H1, at the lower end of a gas supply pipe 20, there being a gasket 2| disposed between the flanges l8 and 9 to assure a fluid-tight seal therebetween. Pipe is connected to any suitable source of supply of a suitable combustible gas.

Head I6 is provided, at its lower end, with an outwardly extending peripheral flange 22 and, at each end, with a reenforcing rib 23 integrally connecting flange 22 and head IS. A nozzle member 24, provided at its upper end with an outwardly extending peripheral flange 25, is bolted to flange 22 of head I6, there preferably being a sealing gasket 25 interposed between the flange 22 of head It and flange 25 of nozzle member 24 to assure a fluid-tight seal therebetween. The head l6 and the nozzle member 24 together constitute a unit which is mounted on stands 28 suitably secured, as by bolting or welding, to frame I0 of the machine at the sides thereof. Conveniently, the end portions of head I8 are bolted to the upper ends of the stands 28, though the unit comprising head it and nozzle member 24 may be mounted in any other suitable manner.

An angle bracket 30 is secured to the inner side of each of the stands 28, conveniently by welding, and is disposed lengthwise of the machine frame It with its upper arm projecting horizontally inward from stand 28. A pair of angle plates 3| is disposed adjacent each of the stands 28, each with its lower arm extending horizontally outward toward the adjacent stand and seating upon the upper flange of the corresponding bracket 30, to which it is bolted. .A plate 3| is welded to the outer face of the vertical arm of each of the angle plates 3|. The angle plates 3| are disposed in pairs aligned transversely of machine frame l0 and the inner vertical arms of such pairs are connected by two tubular frame members 32, conveniently formed of steel piping of suitable length, the ends of which members 32 seat against the inner faces of the vertical arms of plates 3i and are welded thereto at 33. The members 32 and angle plates 3! together constitute frame members mounted upon the angle brackets 30 in position for supporting the refractory hood structure constituting the lower portion of the ignition furnace. The angle plates 3| and plates 3W, adjacent one of the stands 28, are suitably bored and tapped for reception of pipes 34 threaded therein, each provided with a suitable valve 35. The other plates 3| and 3| are also bored and tapped for reception of pipes 36 threaded therein, the pipes 34 opening intoione end of the tubular members 32, and the pipes 36 opening into the other end thereof, as will be understood. Conveniently, the pipes 36, which are discharged pipes, have their outlet ends disposed above funnels 3l' connected by piping 38 to a drain or discharge pipe 39 which may lead to waste. The pipes 34 are connected to a suitable source of supply of cooling water which flows through the tubular members 32, from which it is discharged through the pipes 36 into the funnels 37 and thence to waste.

The nozzle member 24 tapers downward in width, as shown more clearly in Figure 3, and is provided at its lower portion with a downwardly extending relatively narrow tip member ,40 through which extends a downwardly flaring slot 4| for discharge therethrough of the fuel, conveniently gas. Firebricks 42, of generally triangular shape as shown in Figures 3 and 5, seat in sidewise contact upon the tubular members 32, as shown in Figures 1 and 2, each of these bricks being provided, adjacent its lower end, with a shoulder 43 in the lower face of which is formed an upwardly extending arcuate recess 44 conforming to the curvature of the upper portion of the tubular member 32. At its inner portion, each of the bricks 42 is provided with, a downwardly projecting element 45 the lower face of which is substantially in the plane of the bottom of the associated tubular member 32. It will be seen that the center of gravity of each of the firebricks 42 is disposed a considerable distancefrom the associated tubular member 32, in the direc ,tion of tip. member 40, so that the firebrick-tends to turn inward about the tubular member 32 so as to bring the fiat inner face 45a at the upper inner end thereofin contact with the lateral face of tip member 40. In that manner the firebricks 42, each of which weighs approximately 1 nine pounds, are heldby gravity in position upon the tubular members or pipes 32, with their inner upper end surfaces 45 pressed against the exterior lateral surfaces of tip, member 4!]. ,When it is desired to remove one of the firebricks 42, it may be swung about the associated pipe 32, from its full line position shown in Figure 3 to its dotted line position shown at the right of this figure, and may then readily be lifted from the pipe 32 and replaced by a similar firebrick. The

end walls of tip member 40 are flat, and two end 'firebricks 41, formed as shown in Figures 4 and 6,

are mounted upon the pipes 32- at each end of the tip member 40, the opposed faces of these firebricks 41 being flat and in contact, as shown in Figure 4. Angle retaining strips 48 extend between and above the pipes 32 adjacent the ends thereof, and are anchored thereto, conveniently ,by means of U bolts 49. The retaining strips 48 restrain the end bricks 41, and the intermediate bricks 42 therebetween, against movement end- Wise of the pipes 32, thus retaining the bricks in proper assembled relation. Each of the end bricks 41' is provided with an outwardly extending shoulder provided with an arcuate recess 5! conforming in curvature to the pipe 32, for seating thereon, and has a downward extension 52 at the inner side of recess 5|. These bricks are supported upon the pipes 32 in the same manner as the intermediate bricks 42, but have their opposed faces vertical and flat so as to seat one against the other, when the bricks 41 are mounted upon the pipes 32.

The inner faces of the bricks 42 are of para bolic curvature, as shown in Figure 3, and it will be seen that the bricks 42 at the opposite .7

sides of the tip member 42define a downwardly flaring combustion chamber 55 of'parabolic cross section extending the length of tip member 40, with slot 4| opening into the top of this chamber, the ends of which are closed by the end bricks 41. The bricks 42 and 41, together with the frame structure comprising the pipes 32, constitute a refractory water-cooled hood for the ignition burner, the lower face of this hood being spaced a short distance 56 (Figure 1) above the:

upper surface of'the layer or bed [3 of material to be ignited, in the pallet l2. Gas or other suitable fuel is admitted to the combustion chamber 55 through slot 4| of tip member 40 and is mixed with air drawn into the space beneath the hood by the action of the wind box M, the mixture being ignited and providing a mass of flame filling the combustion chamber 55. This flaming mass serves to ignite the upper surface of the bed l3 in the manner previously described.

The pipes 32, in addition to supporting the bricks 42 and 41, also provide means for cooling the hood structure by circulating a cooling liquid, conveniently water, through the pipes 32. It will be noted that the pipes 32 are disposed at the lower portion of the hood structure, that is, adjacent the lower ends of the firebricks, and serve to cool the portions thereof subjected to the most intense heat, such cooling preventing or greatly reducing burning away of the lower portions of the firebrick. In that manner the lower faces of the bricks are maintained in an unburned and smooth and even condition, thus maintaining the space 56 between the bottom of the refractory hood structure and the upper face .of the'bed of material I3 in the pallets l2 sub- .stantiallyconstant, which is conducive to uniform ignition of the upper face of the bed of material and. assures maximum efficiency of the ignition furnace; IIhe bricks of the hood structure may be removed and replaced as desired, or as may be necessary, in the manner previously described, and, ordinarily, without altering the positions of the angle retaining strips 48. Where desirable, either one of the strips 48 may be moved a short distance outward along the pipes 32, byreleasing the U bolts 49, facilitating removal andreplacement of the bricks, particularly the end bricks,4 1., While the pipes 32 of the hood structure preferably are disposed at the lower portion thereof, as shown and above described, they may be otherwise suitably disposed, within the broader aspects of my invention, which comprehends a hood structure provided with cooling means effective for preventing or reducing objectionable burning of the refractory of such structure. As above indicated, and as will be understood by those skilled in this art, changes in construction and arrangement of parts of my invention maybe resorted to without departing from the field and scope thereof,.and I intend to include all such variations, as fall within the scope of the appended claims, in-this application in which'the preferred form only of my invention has been disclosed.

I claim:

1. In an ignition furnace for sintering machines, a fuel supply retort having a downwardly extending tip member, a supporting frame disposed below said retort provided with substantially horizontal tubular members disposed at opposite sides of said tip member, said tubular members being adapted for circulation therethrough of a cooling fluid, refractory members seating adjacent their lower ends on'the upper portions of said tubular members and seating adjacent their upper ends against the opposite sides of said tip member defining a downwardly opening combustion chamber, said refractory members being free from each other and from said tubular members and said tip member for individual removal'and replacement, said tip member opening into said chamber for supplying fuel thereto, andrefractory members mounted'on said "tubular 'members'closing the ends of said chamber.

2. In an ignition furnace for sintering machines, a fuel supply retort, supporting means for said retort, a supporting frame mounted on said supporting means comprising substantially horizontal tubular members disposed below and at opposite sides of the retort, said tubular members being adapted for circulation therethrough of a cooling fluid, said retort having a downwardly extending nozzle member, refractory members seating at their outer lower portions on the upper portions of said tubular members with their upper end portions in contact with said nozzle member at opposite sides thereof defining a downwardly opening combustion chamber, said refractory members being free from each other and from said tubular members and said nozzle member for individual removal and replacement, said nozzle member opening into said combustion chamber, and refractory members mounted on said tubular members closing the ends of said chamber.

3. In an ignition furnace for sintering machines, a pair of supporting stands, a substantially horizontal fuel supply retort extending between and supported by said stands, said retort having adownwardly extending nozzle member, a supporting frame mounted on said stands below said retort, said frame comprising substantially horizontal tubular members at opposite sides of the retort adapted for circulation therethrough of a cooling fluid, and refractory members mounted at their lower outer portions on the upper portions of said tubular members with their upper inner portions in contact with said nozzle member at opposite sides thereof, said refractory members defininga downwardly opening combustion chamber and said retort opening into said chamber for supplying fuel thereto, said chamber being closed at its ends.

4. In an ignition furnace for sintering machines, a pair of-supporting stands, a substantially horizontal fuel supply retort extending between and supported by said stands, a frame supported by said stands below said retort comprising substantially horizontal tubular members at opposite sides of the retort adapted for circulation through them of 'a cooling fluid, and refractory members provided at their outer lower portions with recesses conforming to the upper portions of said tubular members, said refractory members seating on the tubular members with their upper inner ends in contact with the lower portion of said retort defining a downwardly opening combustion chamber, said chamber being closed at its ends and said retort opening into said chamber for supplying fuel thereto.

5. In an ignition furnace for sintering machines, a substantially horizontal fuel supply retort having a downward extension, substantially horizontal tubular members disposed below said extension at opposite sides thereof and adapted for flow therethrough of a cooling fluid, and refractory members seating at their outer lower portions on the upper portions of said tubular members extending therefrom upward and inward to said extension and seating at their upper ends against opposite sides thereof defining a downwardly opening combustion chamber, said extension opening into said chamber for supplying fuel thereto, said refractory members being free from each other and from said tubular members and extension for individual removal and replacement.

6. In an' ignition furnace for sintering machines, a substantially horizontal fuel supply retort having a downward .iextension, substantially horizontal tubular member disposed below said extension at opposite sides thereof andadapted for fiow therethrough of a cooling fluid, and refractory members seating at their outer lower portions on the upper portions of said tubular members extending therefrom upward and inward tosa'id extension and seating at their upper ends against opposite sides thereof, said refractory members being disposed in sidewise contact and 'havingtheir inner faces extending downward and outward from said extension defining a downwardly opening combustion chamber receiving fuel from said extension and being free from each other and from said tubular members and extension for individual removal and replacement.

7. In an ignition furnace for sintering machines, a substantially horizontal fuel supply retort having a downward extension, substantially horizontal tubular members disposed below said extension at opposite sides thereof and adapted for flow therethrough of acooling fluid, and refractory members of generally triangular shape disposed in sidewise contact seating at their outer lower portions on the upper portions of said tubular members extending therefrom upward and inward to said extension and seating at their upper ends against opposite sides thereof defining a downwardly opening :combustion chamber,.said extension opening into said chamber for supplying fuel thereto, said refractory members being free from each other and from said tubular membersand extension for individual removal and replacement.

8. In an ignition furnace for slntering machines, a substantially horizontal fuel supply retorthaving a downward extension, substantially horizontal tubular members disposed below said extension at opposite sides thereof and adapted for flow therethrough of a cooling fluid, and refractory members seating at their outer lower portions on the upper portions of said tubular members extending therefrom upward and inward to said extension and seating at their upper ends against opposite sides thereof, said refractory members being disposed in'sidewise contact and having their inner faces of substantially parabolic curvature defining a, downwardly opening combustion chamber of substantially parabolic cross section receiving. fuelfrom said extension and being free from each other and from said tubular members and extension for individual removal and replacement.

EDWARD W. SHALLOCK.

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