US2478293A - Hot-blast furnace stove - Google Patents

Description

J. E. MacDoNALD 2,478,293

HoT-BLAsT FURNACE sTovE Filed Jan. 26, 1946 2 Sheets-Sheet l ATTORNEY E. MacDoNALD 2,478,293

HOT-BLAST FURNACE STOVE Filed Jan. 26, 1946 2 Sheets-Sheet 2 INVENToR JAMES E. MAcoNA/.o

ATTORNEY Patented Aug. 9, 1949 UNITED STATES PATENT ol-'FicE HOT-BLAST FURNACE STOVE James E. MacDonald, Latrobe, Pa. Application January 26, 1946, Serial No. 643,615

Claims. (Cl. 263-19) Hot-blast stoves for furnaces have heretofore included two general types. In one or these types, the combustion space has been included within the circular shell of the checker chamber, and in the other type, a combustion chamber has been built separately from the shell and wall of the checker chamber and connected to the checker chamber by a suitable nue or passageway through which the gases of combustion are directed into the checker chamber to heat the checker brick-s, the flow then being reversed through the checker chamber, to heat incoming cold air which then is directed to the blast furnace or other point of consumption. The conventional blast furnace requires four hot-blast stoves.

My invention possesses a number of advantages not present in the previous structures and avoids certain disadvantages of these prior stoves. Among these advantages are:

Greatly increased checker space through placing of the combustion chamber outside of the shell of the checker chamber, without the great heat losses through radiation such as occurs through the use of a separately built combustion chamber;

An improved arrangement of combustion chamber and method of firing, which will reduce damage to the combustion chamber lining, in that the burner flame will not impinge against the brick work as in the conventional stove;

An arrangement of the combustion chamber with respect to the checker chamber whereby the two chambers will occupy a smaller space than heretofore required for separately-built combustion and checker chambers, and

The provision of a combustion chamber of such form that it Acan lbe installed or replaced without dismantling the entire hot-blast stove, and whereby the old type of 21foot diameter stove can readily be changed to secure the capacity of a 25-foot diameter stove with conventional combustion chamber construction.

Another object of my invention is to provide a hot-blast stove of such form that three stoves will be sufficient for a blast furnace that required four stoves of the previously used types.

As shown in the accompanying drawings, Figure 1 is a vertical sectional view, partly fragmentary, of a checker chamber and burner chamber built according to my invention and taken on the line I-I of Fig. 2, and Fig. 2 is a fragmentary view taken on the line II-II of Fig. l.

The structure comprises a checker chamber 3 2 and a burner chamber 4. The checker chamber is provided with the usual checker bricks 5`which may be of any suitable form, such as those shown in my Patent 2,034,820 for example. The shell and lining of the checker chamber may also be of any suitable materials. In the present instance however, one side of the checker chamber is of somewhat flattened form, the iiattened portion being formed of bricks 6. This feature provides for compactness of arrangement of the burner chamber and the checker chamber, and also breaks the circular continuity of the interior wall of the checker chamber, thus avoiding the objectionable "swirling" (which frequently occurs in checker chambers of completely circular form), through avoidance of creeping of the checker bricks during operation of the furnace. The metal shell 1 of the combustion chamber is secured to the metal shell 8 of the checker chamber by metal gusset plates 9 that are welded to the shells and are spaced apart at suitable vertical distances, at each side of the structure,

It will be seen that the burner chamber 4 is of elongated or oval form, in a horizontal direction, so that the flame of gas which is supplied thereto through a gas inlet or nozzle I0 need not have direct impingement against the walls or lining of the burner chamber, thus avoiding rapid deteri-4 oration of the lining. The lower portion of the outer wall of the combustion chamber is of greater thickness, as indicated at Il, than is the upper portion I2 thereof.

The stove will be operated in accordance with the usual practice, namely, the hot gases will be directed from the burner cham-ber through the checker work to the opening i3 below the checker work, and after the checker bricks have been heated, a flow of air will be set up reversely through the system and out a hot-blast opening i4 positioned slightly above the burner.

It will be seen that not only does the shape of the burner chamber 4 enable me to increase the liie of burner chambers, through avoidance of impingement and intense heating of the burner chamber walls by the burner flames, but also enables me to apply an outside burner chamber to a checker chamber within a relatively small space, as compared to those structures wherein burner chambers are built in spaced relation to or separately from the checker cham-bers. This is of importance when applying the stove to existing blast furnaces and stoves which are usually located in such close proximity to one another that there is insufficient space to add a separately built combustion chamber.

While the stove can, ot course, be made of various dimensions, it is desirable to provide proper proportions as between the sizes of the checker chamber and the burner chamber. For example, with a checker chamber whose internal diameter is 18 feet and having an eiective height of approximately 100 feet, the burner chamber ma'be of approximately the same height, with its greatest internal diameter 9 feet and its narrowest internal width or diameter 3 feet, near the bottom of the chamber, this diameter being slightly increased at the upper part of the chamber, because of the reduced wall thickness, as shown in Fig. 1. With chambers of these dimensions, the horizontal iiue area in the lower portion of the combustion chamber is approximately 21.75 square feet,A while the horizontal area of the checker chamber is about 250 square feet. With a checker. chamber of the dimensions described, and with checker bricks such as those shown, the total checker brick surface area for absorption and radiation of heat will be about 220,400 square feet.

In commonly used installations, wherein the burner chamber is built within a circular shell that encompasses the checker chamber, the combustion chamber usually requires 25% to 35% of the space within the shell.

I claim as my invention:

1. A hot-blast stove comprising a checker chamber mainly of circular contour in cross section and a burner chamber communicating therewith, the wall of the checker chamber being mainly of circular contour, in cross section, but flattened interiorly and exteriorly for a limited distance, and a burner chamber having abutting engagement with the said exteriorly-attened surface, the flattened portion of the wall extending radially beyond circular lines that encompass the checkerwork.

2. A hot-blast stove comprising a checker chamber mainly of circular contour in cross section and a burner chamber communicating therewith, the wall of the checker chamber being mainly of circular contour, in cross section, but flattened for a limiteddistance, interiorly and exteriorly, and the burner chamber having abutting engagement with the said exteriorly-attened surface and being of horizontally-elongated form in a direction 'parallel to the plane of the said flattened area, the ilattened portion of the wall extending radially beyond circular lines that encompass the checkerwork.

3. A hot-blast stove comprising a checker chamber that is mainly of circular contour, in cross section, but a portion of its wall being disposed inwardly of a true circle, for a limited distance, a burner chamber positioned against the outer face of said wall portion and radially beyond circular lines that encompass the checkerwork, and metallic reinforcing bands embracing both the checker chamber and the stove, to support their walls and to hold them against relative displacement.

4. A hot-blast stove comprising a checker chamber and a burner chamber, the wall of the checker chamber being mainly of circular contour, in cross section, and the burner chamber being disposed against the wall of the checker chamber and extending therealong horizontally for a. distance substantially less than one-half the circumference of the checker chamber, and having communication with the upper end of the checker chamber, a metal shell that encompasses the checker chamber wall along circular lines for more than one-half of its circumference and to vertical lines of juncture with the exterior surface of the burner chamber wall, a portion of the shell structure being extended radially beyond said lines to encompass the outer face of the burner chamber wall and having a radius of curvature that is shorter than the radius of the checker chamber.

5. A hot-blast stove comprising a checker chamber and a burner chamber, the wall of the checker chamber being mainly of circular contour. in cross section and of greater width than the burner chamber, and the burner chamber being disposed against the wall of the checker chamber and extending therealong horizontally for a distance substantially less than one-half the circumference of the checker chamber, and having communication with the upper end of the checker chamber, a metal shell that encompasses the checker chamber wall along circular lines for more than one-half of its circumference and to vertical lines of juncture with the exterior surface of the burner chamber wall, a portion of the shell structure being extended radially beyond said lines to encompass the outer face of the burner chamber wall, the wall section that separates the two chambers being disposed mainly radially outward of a circle that encompasses the checker Work.

JAMES E. MAcDONALD.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,849,657 Boynton Mar. 15, 1932 1,860,368 Seaver May 31, 1932 1,983,017 Bowland Dec. 4, 1934 2,257,453 Bowland Sept. 30, 1941 2,408,728- Bowland Oct. 8, 1946

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