US2432779A - Checkerwork for furnaces - Google Patents

Description

Dem l, 194?. J MacDONALD 2,432,779

CHECKERWORK FOR FURNACES Filed Jan. 15, 1944 2 Sheets-Sheet 1 ATTORNEY 4 e 4 w. 1 i 1 1 A 1| OM. T N m m a m F .0 m 9 5 E 1 H .\\.\//\\V rl w H a J I.

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Dec. 16, 1947. J, E, MCDONALD 2,432,779

CHECKERWORK FOR FURNACES Filed Jan. 15, 1944 2 Sheets-Sheet 2 I INVENTOR James 15. (Vacflamua.

his ATTORNEY Patented Dec. 16, 1947 UNITED STATES PATENT. OFFICE 2,432,779 CHECKERWORK FOR FURNACES J ames' E. MacDonald, Latrobe, Pa. Application January 15, 1944, Serial No. 518,339

8 Claims. (01. 263-51) My invention relates to checkerwork for use as a regenerator structure with openhearth furnaces, glass tanks, blast furnace stoves, and other heating furnaces.

Checkerwork of this nature should have its heat-exchanging elements of suflici'ently small section or thickness to avoid inert volumes of refractory material within said elements. Where too much mass exists, there is an undesirable time lag in heat exchange during the reversal cycles which usually are about 15 minutes or 20 minutes in each direction. However, the checkerwork elements must not be so light or thin that the checkerwork will sag or break down at the high temperatures, to which it frequently is subjected.

One object of my invention is to provide a checker structure of such form that there are an ample number of heat-exchanging elements of the required small section or thickness to avoid undue time lag and with sufiicient total area to effect the desired rapid heat absorption and radiation, but which structure is of, sufiicient strength to withstand the high temperatures, without deformation.

Another object of my invention is to provide a checker structure formed of elements of given sizes that can readily be arranged to form flues or passageways of various widths through the checkerwork.

Another object of my invention is to provide checkerwork of such form that substantial quantitles of dust cannot accumulate therein, and wherein I avoid eddy currents that would tend to cause dust to be deposited and which would tend to reduce the velocities of air and gas that are passed through the oheckerwork.

Still another object of my invention is to provide heat exchange elements of such form that larger portions of their surface areas are exposed to th air and gas than in the case of elements of other shapes and arrangements.

A further object of my invention is to provide checkerwork of such form that it is not likely to become clogged, thus avoiding the necessity for the frequent cleaning that is required with some other types of checkerwork.

In the accompanying drawing, Figure 1 is a longitudinal sectional view through a portion of a furnace and checkerwork embodying my inven tion; Fig. 2 is a perspective View, on an enlarged scale, of one of the bricks employed in building the checkerwork; Figs. 3 and 4 are perspective views, on an enlarged scale, of two of the heateXchanging elements that are supported byithe bricks formed as shown in Fig. 2; Fig. 5 is a plan view, on an enlarged scale, of a portion of the checkerwork of Fig. 1; Fig. 6 is taken on a line VI--VI of Fig. 5; Fig. 7 is a plan view similar to Fig. 5, but showing a variably-spaced arrangement of. the checker columns; Fig. 8 is a view similar to Fig. 6, but showing checker elements of a modified cross sectional form; Figs. 9 and 10 are perspective views showing the long and short elements respectively of Fig. 8; Fig. 11 shows still another modification of the structure of Fi 6; Figs. 12 and 13 are perspective views of the checker elements of Fig. 11, and Fig. 14 is a perspective view showing another manner in which the column bricks may be formed.

For convenience of description, I have shown the invention as employed in connection with an openhearth furnace. A portion of the furnace chamber is indicated by the numeral 8, the furnace having the usual bridge wall 9 and checker chambers at its opposite ends, one of such chambers being indicated by the numeral l 0. Supporting bricks or blocks l I and if! of conventional form are provided for supporting the checkerwork, the air flowing up through this open-work foundation ll-l2 and through the checkerwork. The waste gases pass over the bridge wall and down through the checkers.

The checkerwork comprises bricks l4 that are placed in superposed relation, to form laterally spaced columns that support heat exchange elements l5 and IS. The bricks i i are of rather massive form as compared to the heat exchange elements, to provide th required structural strength so that the checkerwork will withstand the usual high temperatures without deformation. The bricks may suitably be approximately 5 inches square in horizontal section and of about 6 inches vertical length, it being obvious that bricks of other dimensions will be used, to suit desired conditions. In order to provide for more rapid heat absorption and radiation and to thereby avoid tim lag in heat exchange during reversal cycles, the heat exchange elements l5 and 16 may suitably be of 3 inches in diameter or thickness. These elements are preferably made of circular or rod-like form so as to avoid the fiat surfaces on which dust and solid products of combustion could accumulate and to provide for smoother and high velocity of gas and air flow, without eddying of the gas and air.

The bricks I l have semi-circular recesses formed at their ends, at each of their 4 sides and when the bricks are built up on one another to form columns, circular recesses are thereby formed into which the ends of the bars l5 and IE will be set, as shown more clearly in Figs. 5 and 6. The bars I6 are of short length as compared to the bars I5, since the bars I5 will, in some cases, extend completely through the columns, as shown for example at the lower lefthand corner of Fig. 5, in which case the bars I6 can extend into the columns only a limited distance. While the bars I5 may, in some cases, be little, if any longer than the bars I6, I prefer to make them of relatively great length so that each is of a length two or three times greater than the length of the bars I5. The utility of this arrangement is that the columns can be set at various distances apart in directions longitudinally of the checker chamber and the bars I5 to provide uptake and downtake passageways of various sizes, without the necessity of providing bars I5 of various lengths. For example, all of the vertical passageways can be made either larger or smaller than shown in Fig. 1, simply by setting the columns at various distances apart, along the bars I5. Also, some of the vertical passageways may be, in this manner, made larger or smaller than others, as shown in Fig. '7. For example, the columns near the bridge wall 9 may be adjusted longitudinally of the bars I5, to provide wider passageways than are present between columns that ar more remote from the bridge wall.

It will be seen that while the main flow of gas and air will be in vertical paths or passageways between the columns, there will be lateral relief or slight flow between the bars I5 and between the bars I6, from one vertical path or passageway to adjacent vertical passageways thus affording better distribution of gas and air.

While my invention in its broader aspects could include heat exchange bars I5 and I6 of rectangular instead of circular form, I prefer the rod-like form shown in the drawing, because the rounded or curved surfaces are not likely to cause accumulation of substantial quantities of dust or solid products of combustion, and furthermore cause a smoother flow of gas without eddying thereof such as occurs where heat exchange elements are employed that have flat surfaces disposed at right angles to the main passageways through the checkerwork.

In Figs. 8 to 10, I show an arrangement wherein checker elements or bars I9 and 20 are of rectangular form rather than circular in cross section. The recesses in the ends of the column bricks 2% are also of angular form instead of curved. The element I9 and 20 will be assembled with the columns in the same manner as are the element I5 and IS, the elements I9 and 20 being so positioned that they have convex upper and lower surfaces, to facilitate the flow of gas and air and to prevent the accumulation of dust thereon and the forming of eddy currents.

Similarly, in Figs. 11 and 12, I show checker elements 22 and 23 arranged with column bricks 2'4 in the manner similar to that shown in Figs. 1 to 6, the elements 22 being of oval form in cross section. In addition to possessing the advantages of the round bars of Fig. 1, the oval bars 2223, arranged with their widest diameters vertical, give wide heat-exchange areas, without unduly large cross sectional area, since their horizontal thickness need not be any greater than the diameter of the roundbars, or may be of even less thickness, with greater surface area.

Instead of forming the column bricks with recesses in both the upper and lower ends, I may form them in halves that have abutting flat surfaces, as indicated by the elements 25 in Fig. 14, the upper end of one half-brick and the lower end of the other half-brick being suitably recessed for the reception of bars of the shape shown in any of the other figures.

I claim as my invention:

1. Refractory checkerwork comprising laterallyspaced columns arranged in laterally-spaced rows and each formed of a plurality of bricks in superposed relation, the bricks having recesses formed therein at their abutting ends, and horizontallyextending heat-exchanging elements having their ends supported in the said recesses, the recesses that support the elements which extend in one horizontal direction extending completely through the columns and the associated elements being movable lengthwise through said recesses, whereby the columns may be placed at various distances apart, in said direction.

2. Refractory checkerwork comprising laterally-spaced columns arranged in laterallyspaced rows and each formed of a plurality of bricks in superposed relation, the bricks in each column each having recesses in their upper and lower ends, that are in vertical alinement with the recesses in the vertically-adjacent ends of abutting bricks, and horizontally-extending heatabsorbing elements having their ends extending into the said recesses.

3. Refractory checkerwork comprising laterally-spaced columns arranged in laterallyspaced rows and each formed of a plurality of bricks in superposed relation, the bricks in each column each having recesses in their upper and lower ends, that are in vertical alinement with the recesses in the vertically-adjacent ends of abutting bricks, horizontally-extending heat-absorbing elements having their ends extending into the said recesses, and other horizontallyextending heat-absorbing elements extending completely through certain of said recesses and the columns, at right angles to the first-named elements.

4. Refractory checkerwork comprising laterally-spaced columns each formed of a plurality of bricks in superposed relation, the bricks in each column each having recesses in their upper and lower ends, that are in vertical alinement with the recesses in the vertically-adjacent ends of abutting bricks, and horizontally-extending heatabsorbing elements having their ends extending into the said recesses. the said al ned recesses at the abutting ends of the bricks being of approximately semicircular contour in each brick. and the said elements being in the form of round bars.

5. Refractory checkerwork comprising laterally. spaced columns each formed of a plurality of bricks in su erposed relation, the bricks in each column each having recesses in their upper and lower ends, that are in vertical alinement with the recesses in the vertically-adjacent ends of abutting bricks, and horizontally-extending heatabsorbing elements having their ends extending into the said recesses, the said elements being of convex form on their upper and lower sides, and the recesses being formed to fit said sides.

6. Refractory checkerwork comprising laterallyspaced columns each formed of a plurality of bricks in superposed relation, the bricks in each column each having recesses in their upper and lower ends, that are in vertical alinement with the recesses in the vertically-adjacent ends of abutting bricks, and horizontally-extending heatabsorbing elements having their ends extending 5 into the said recesses, the said elements each being of greater width vertically than in horizontal thickness, and the recesses being formed to fit the elements that are engaged thereby.

7. Refractory checkerwork comprising bricks arranged to form laterally-spaced columns that are placed to form rows which extend at right angles to each other, horizontally-extending heatexchanging elements of relatively small cross sectional area extending across the spaces between the columns, in directions parallel to the respective rows, and means on the columns for supporting the said elements at a plurality of verticallyspaced planes, the said elements being in the form of round bars and those elements that extend in one direction being of substantially greater length than the center-to-center spacing of adjacent columns and. the columns having holes through which the last-named elements may extend loosely, to thereby permit of setting the columns at various distances apart, in directions lengthwise of these elements.

8. Refractory checkerwork comprising bricks arranged to form laterally-spaced columns that are placed to form rows which extend at right angles to each other, the bricks having recesses forming in their sides, heat-exchanging elements extending horizontally and supported at their ends in the said recesses, and other horizontallyextending heat-exchanging elements extending completely through certain of the columns, in directions at right angles to the first-named elements, the columns being adjustable longitudinally of said other elements.

JAMES E. MACDONALD.

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

UNITED STATES PATENTS

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