US1953342A - Checkerwork construction - Google Patents

Description

Apnl 3, 1934. A. FOELL CHECKERWORK CONSTRUCTION 2 Sheets-Sheet 1 Filed O01I Snnentor April 3, 1934. A. l.. FoELL.

QHECKERWORK CONSTRUCTION Filed oct. 11, 1932 2 sheets-sheet 2 mventor Patented Apr. 3, 1934 UNITED STATES PA ich 7 Claims.

This invention relates to regenerative heaters and more particularly to an improved form of checker Work construction especially adapted for use in hot blast stoves for blast furnaces and the like.

Although my invention is adapted to be used in many types of apparatus in which refractory material is arranged in what is commonly known as checker Work, the following description and the accompanying drawings illustrate my invention applied to the usual form of hot blast stove. I do not, however, limit myself to this specific application as it will be readily understood by those skilled in the art that my invention may be applied to other uses. Y

A great many of the hot blast stoves now in eX- istence contain checker work comprising relatively large checker openings of round, square, rectangular or other cross sectional shape laid up of ordinary rectangular brick or special shaped tile. In the usual type of hot blast stove the checker work is provided with vertically extending openings or fiues which are adapted to alternately convey the hot gases to heat and the air to be heated by the f checker Work and in this way effect the desired heat transfer in the usual manner. Stoves of this type with large checker openings have a necessarily limited amount of heating surface and, in many cases, the amount of heating surface is insuflicient to properly serve the present day demand for higher hot blast temperatures and more eiiicient stove operation. With the advent of improved methods of cleaning the blast furnace gas which is used to heat the hot blast stoves the above noted large checker openings are'no longer necessary for the purpose of stove cleaning and it has been found that by reducing the size of the checker openings and increasing the amount of heating surface per unit of stove volume much greater hot blast stove efficiencyY is obtained.

In many instances the above noted large checker stoves are still capable of many years of service and therefore cannot justifiably be replaced by new stoves having smaller-checkerl openings `and greater surface even though the need of increased heating surface strongly exists.

It is, therefore, among lthe objects of my invention to provide means for increasing the heating surface of the existing checker Work of hot blast stoves and the like without the necessity of completely rebuilding the checker work.

Other objects of my invention are: the provision of a filler brick which can be readily inserted in the checker openings of existing hot blast stoves regardless of whether the checker openings or flues are perfectly true in size from top to bottom or are irregular due to unavoidable discrepancies in the original laying up of the checker brick Work or subsequent shifting of ysuch brick Work during operation; the provision of filler 601 bricks for checker work which are self aligning and self arranging in orderly fashion when placed in the checker openings; the provision of filler bricks which can be easily handled and placed in existing checker work and which may be easily 55"; removed when and if desired; the provision of a checker work construction in which the desired turbulence in the flow of gas or air through the fiues is obtained thereby increasing the efficiency of the heat transfer; the provision of means for improving the efficiency of the present large checker hot blast stoves and the like at a minimum cost of manufacture and installation.

The above and other objects of my invention will appear from the following description of a preferred form thereof, reference being had to the accompanying drawings. Broadly, it may be stated that I propose to increase the heating surface and the volume of the refractory material of a checker work installation by placing 89 spherical or otherwise suitably. shaped bodies of refractory material into each of the checker openings or flues and properly supporting such refractory bodies in the checker opening.

In the drawings- Figure l is a vertical section through a portion of the checker work of a hot blast stove.

Figure 2 is an enlarged horizontal cross section ofthe checker Work shown in Figure 1 and taken on line 2 2 of Figure 1. 90

Figure 3 is a fragmentary View generally similar to Figure 2 but taken onY line 3-3 of Figure 1. v

Figure 4 isV a View similar to Figure 1 but showing a modified form of support for my iiller bodies.

Figure 5 is a'horizontal section taken 5 5 of Figure 4.

Figure 6 is a fragmentary sectional View of the lower ends of the flues of a hot blast stove illustrating another form of support for the filler brick.

Figure '7 is a horizontal section taken on line 7--7 of Figure 6. Y

Figure 8 is a view generally similar to Figures 1 and 4 but showing a spheroidal form ofiiller brick.

Figure 9 is a horizontal section taken on line 9--9 of Figure 8. Y 110 Figure 10 is a plan view of a flue illustrating on line a modified arrangement of spherical ller brick.

Figure 11 is a vertical sectional view taken on line 11-11 of Figure 10.

Figure 1 illustrates a common form of checker Work construction in which rectangular brick 10 are laid up in layers or courses in such a manner that vertical openings or ues 11 are formed. The brick 10 are supported by the refractory supporting members 12 and 13 or by any other suitable supporting means.

For purposes of description we may assume that the kind of checker work illustrated is such as is employed in one of several types of hot blast stoves in use prior to the advent of the improved present day methods of cleaning the gases which are used in firing hot blast stoves. In order to adapt this type of stove to the present day relatively clean gas operating conditions and secure the highest eiciency therefrom I propose to insert in the flues 11 a plurality of spherical bodies 14. These bodiesor ller bricks 14 are made of suitable refractory material and are preferably inserted into the flues or openings 11 from the topy of the stove. To maintain the ller brick 14 in position in the ues I provide a grating 15, which may be of metal or refractory material, supported on the arch members 13 and which, while it permits the free flow of gas through the ues 11, supports the filler brick 1'4 which are inserted in the nues.

Iprefer to make the spherical filler brick 14 of smaller diameter than the smallest cross sectional dimension of the flue openings. The ue openings which are illustrated and in general use are of square cross section and it will be clearly seen from Figure 2 that the successive filler brick 14 will assume their positions in diagonally opposite corners of the flue openings 11.

Thus, the brick 14 will naturally fall into a staggered or stepped arrangement in the flues 11. Although I do not wish to limit myself to any specic size of ller brick, I have-found that, in using spherical filler brick in checker work having square flue openings, it is desirable to make the spherical fillers of a diameter equal to substantially two-thirds of the side of the square flue openings as this proportion greatly increases the heating surface of the checker work and offers the minimum of resistance to the passage of gas and air through the stove.

Figure 3, which is a cross section taken through the point of tangency between two adjacent ller brick 14, illustrates the fact that, whenV spherical filler brick having a diameter equal to substantially two-thirds of the side of the square flue opening are used, the maximum total obstruction of the original fiue opening is never greater than the central cross sectional area of one of thespherical bodies. y #I have also found that'by varying the diameter of the spherical fillers it is possible to vary the amount of added heating surface per unit of stove checker work volume and to vary the amount of added refractory volume per square foot of added heating surface. In a general way, as the diameter of the spherical fillers is increased the amount of added heating surface perV unit of stove checker work volume is decreased and the volume of refractory persquare foot of added heating surface-is increased. This characteristic makes possible the convenient selection of a filler to best serve the individual requirements of any stoveor set of stoves.

In Figures 4 and 5 a modified form of support Yfor the filler body 14 is illustrated. This support from. It will be seen from Figure 8 that the upper ends of the members 18 provide an effective support for the' bottom ller bricks.

In Figures 6 and 7 another modified form of ller support is illustrated which consists of an inverted hook shaped member 19, preferably of refractory material, although heat resisting metal may be used, which is adapted to be inserted into the flue openings from the bottom thereof and to extend diagonally across the openings, These supports 19 are so shaped that they may be readilywinserted into the bottom of the flue opening but will be rmly heid in position and prevented from dropping out by the weight of the filler bricks 14. However, if it is desired to remove the filler bricks 14 from any nue or flues 11, it is only necessary to insert a suitable tool into the bottom of the flue and against the member 19 and swing the member about its lower end 19', which is supported on the ledge formed at the joint between the supporting members 12 and the refractory bricks 10, to effect its removal and permit the refractory balls`14 to drop out of the ue.

In Figures 8 and 9 I have shown a modified form of refractory body adapted to be inserted in the flues of the checker work of hot blast stoves and the like. In this form of my invention the filler brick 20 are spheroids of substantially ellipsoidal form and may be disposed in the flues in the staggered or stepped arrangement, described above in reference to the preferredV spherical filler units, as shown in the left hand flue of Figure 8 or in the parallel axis arrangement of the right hand fiue (Figure 8) A modied arrangement of spherical filler brick is shown in Figures 10 and 11. In this application of my invention the ball shaped fillers 14 have a diameter equal to approximately veeighths of the side of the square flue opening. When these relatively small fillers are used they arrange themselves in layers or courses in the flues, alternate courses extending across opposite diagonals ofthe flue. This arrangement may be desirable in some cases and indicates the installation flexibility of my filler brick. k

From the above description it will be seen that I have provided a filler brick which may be readily installed in present day types of checker work and which may also be readily removed when desired. Y

It vwill be understood that the filler bricks will be made of such dimensions and used in proper quantities to give the ldesired increase in refractory volume and heating surface for any particular installation. As compared with ller bricks with which I am familiar and which must be accurately tted into the checker work ues, my

iso

iillers of the present day tted types must be made to properly serve a specic application.

The elimination of the possibility of not being able to apply llers in all flue openings of a stove or parts of any individual flues due to disalignment of the iiues or the courses of brick making up the checker work.

The elimination of close manufacturing tolerances which must be maintained in the manufacture of ller brick now in use.

A substantial reduction in the amount oi spalling of fillers during operation.

Increased strength of spherical ller brick, due to their form, which eliminates breakage in handling and in installation. Due to their shape less resistance to the flow of gases is oiered by the spherical ller brick when inserted into stove flues and the addition of a much greater amount of heating surface per unit of stove volume is effected than has been obtained with any previously proposed lier brick with which I am familial.

Although I have described in considerable detail the forms of my invention illustrated in the accompanying drawings it will be understood by those skilled in the art that modifications and variations may be made in the specific form of ller brick utilized, the method of supporting the fillers, etc., without departing from the spirit of my invention. I do not, therefore, wish to be limited to the exact forms herein shown and described, but claim as my invention all embodiments coming within the scope of the appended claims.

I claim:

l. Checker work construction oi the type described having vertically extending fines, spherical filler brick disposed in said iiues and means for supporting said ller brick in said liues.

2. Checker work construction of the type described having vertically extending flues, spherical ller brick disposed in said lues and removable means for supporting said spherical filler brick in said ues.

3. In checker work construction having vertically extending nues, a plurality of spherical Y ller brick disposed in said ues, said filler brick being of a diameter equal to substantially twothirds of the smallest cross section dimension of one of said nues.

4. Checker Work construction having iiue openings of square cross section extending therethrough, spherical ller brick disposed in said ilue openings, said ller brick being of a diameter equal to substantially two-thirds of the side dimensions of the square cross section of one of said flue openings.

5. In a structure of the type described having a vertical iiue, a plurality of substantially spherical ller bricks disposed in vertically stepped arrangement in the flue and means for supporting said ller bricks in the flue, said means comprising a hook shaped member extending across said flue and adapted to support and be held in position by the Weight of the ller bricks.

6. In a structure of the type described having a vertical ue, a plurality of substantially spherical ller bricks disposed in vertically stepped arrangement in the flue and means for supporting said ller bricks in the flue, said means comprising a removable member extending across the bottom portion of said flue and adapted when in one position to be freely movable vertically upwardly in said ue and to be wedged across the flue by the Weight of the ller bricks, and when in another position to be freely movable vertically downwardly in said ue.

7. Checker work construction of the type described having Vertically extending ues, substantially spherical filler brick disposed in said nues, and removable means dispose-d at the lower end of each of said flues for supporting said spherical ller brick in said lues.

ADOLPH L. FOELL.

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