Regenerative heat exchange systems and refractory bricks therefore

A prismatic tubular brick of refractory material for constructing the checkerwork structure of regenerative furnaces, the brick having mirror image top and bottom surfaces and a central passage extending therebetween. Two pairs of opposed parallel side walls of uniform thickness having aligned recesses in the top and bottom surfaces thereof, are connected together by angle portions at their adjacent corner edges. The top and bottom surfaces of the angle portions are elevated with respect to the recessed top and bottom surfaces of the side walls and are of similar size and shape. Accordingly, the elevated and recessed surfaces of one brick cooperate with the elevated and recessed surfaces of another brick to interlock the bricks together in an offset stacked arrangement.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to regenerative type furnaces, and 
more particularly to improvements in regenerative heat exchange structures 
and the bricks or blocks employed in constructing such structures. 
2. Description of the Prior Art 
Such heat exchange structures are used with various types of furnaces 
including those for steel and glass making. The present invention has 
particular utility in glass melting furnaces and will be described herein 
in connection with the checkers of such furnaces. However, it will be 
readily apparent that it may as well be employed with various other types 
of furnaces. 
As is well known, present day flat glass is conventionally produced in a 
continuous tank-type melting furnace, wherein raw batch materials and 
scrap glass, or cullet, are continuously delivered to the charging end of 
the furnace, melted and refined as they move through the furnace, and then 
withdrawn from its delivery or working end as a continuous ribbon. In 
furnaces of this type, heat for melting the raw batch material is provided 
by flames directed through a series of ports arranged along each opposed 
longitudinal side of the furnace above the mass of glass, the ports 
leading to sources of supply of fuel and preheated combustion air. The 
combustion air is preheated by contact with refractory bricks heated by 
hot waste gases which have previously been withdrawn through checkerwork 
structures of a regenerator opposite the ports being fired. The direction 
of firing is periodically reversed, that is, the two series of ports are 
alternately operated so that first one series of ports is fired with the 
opposite series of ports serving to exhaust the hot waste gases. Then at 
periodic intervals, perhaps on the order of 20 to 30 minutes, the 
operating condition of the two series of ports is reversed, that is, the 
ports previously being fired serve as the exhaust ports and the ports 
exhausting the hot waste gases serve as the firing ports. Conventionally, 
the incoming combustion air and the hot exhaust gases are passed through 
checkerwork structures and associated tunnels extending the length of and 
lying beneath the checkerwork structures of the regenerators. 
It is common practice to construct checkerwork structures of standard 
dimension, rectangularly shaped refractory bricks laid up in various 
arrangements commonly known in the art by the terms "basket weave," "open 
basket weave," "open-flue" and various other configurations. In addition 
to the above-mentioned heat exchange structures formed of standard 
dimension, rectangularly shaped refractory bricks, various types of 
specially shaped refractory bricks have been suggested for exclusive use 
in heat exchange systems. Examples of such bricks are disclosed in U.S. 
Pat. Nos. 4,436,144; 4,519,442 and 4,590,039. Generally, these specially 
shaped bricks which have been designed in an effort to achieve higher 
thermal efficiency for specific types of heat exchangers in given 
applications, have the disadvantage of being somewhat mechanically 
unstable when laid up in the checkers. Thus, as the checkers are 
repeatedly subjected to temperature changes over a period of time, the 
structure may fail. 
SUMMARY OF THE INVENTION 
Generally stated, the present invention contemplates tubular refractory 
bricks having their end surfaces formed in such a manner that the bricks 
can be set in parallel rows, and layers of rows can be stacked one upon 
another in interlocking arrangement for producing a mechanically stable 
checker structure having a high thermal efficiency. More particularly, the 
specially configured refractory member comprises a prismatic tubular brick 
having mirror image end surfaces, with a central passage extending 
longitudinally therethrough. Each tubular refractory brick includes two 
pairs of opposed side walls, adjacent longitudinal edges of the side walls 
being interconnected in substantially square relation in cross section by 
angularly disposed corner portions. The central areas of the top and 
bottom, or end, surfaces of each side wall are provided with 
longitudinally aligned concave recesses. For stacking the bricks in 
setting the checkers, the top and bottom surfaces of the corner portions 
are adapted to engage the corner portions of adjacent vertically aligned 
bricks, or to be received in the aforementioned recesses of offset or 
staggered bricks for interlocking the bricks one to another. 
OBJECTS AND ADVANTAGES 
An object of the invention is to provide a refractory brick of novel 
configuration for assembly of a mechanically stable checkerwork structure. 
Another object of the invention is to provide a specially shaped refractory 
brick which is adapted to interlock with similarly shaped refractory 
bricks for producing checkerwork structures of high thermal efficiency. 
Other objects and advantages of the invention will become more apparent 
during the course of the following description, when taken in connection 
with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
It will be understood that while the checkerwork structure and bricks 
employed therein have been described herein in the environment of a 
continuous glass melting furnace, they may also advantageously be employed 
in other furnaces. Thus, with reference to the drawings, and more 
particularly to FIG. 1, there is illustrated a portion of a continuous 
tank-type regenerative glass melting furnace, designated in its entirety 
by the reference numeral 10, embodying the present invention. 
Generally, the glass melting furnace 10 comprises a covered, longitudinally 
extending tank 11 and a pair of regenerators 12 and 12a, one extending 
along each side of the tank 11. The tank 11 conventionally includes 
opposed side walls 13 and 13a and a charging or doghouse area (not shown) 
at one end. As is well known raw glass making materials, i.e. batch and 
cullet or scrap glass, are introduced into the charging area by feeder 
devices (not shown) and reduced to a molten mass 14 within a melting zone, 
from which they flow into and through refining and cooling zones, and are 
thereafter removed from the opposite or exit end of the tank 11 in 
accordance with any of the well known glass forming techniques. 
Heat for reducing the batch to molten glass within the melting zone is 
provided by suitable means such as burners (not shown) which discharge hot 
flames and products of combustion through two series of ports 15 and 15a 
opening into the melting tank 11 above the level of the molten glass 14 
flowing therethrough. As is common with furnaces of this type, the 
individual ports (only one shown) of each series 15 and 15a are arranged 
at spaced intervals along the sides 13 and 13a, respectively, with the 
number of ports employed being predicated upon a predetermined maximum 
melting capacity set for the furnace 10. 
Referring now in particular to FIGS. 1, 2 and 3, each regenerator 12 and 
12a includes a checkerwork structure 16 constructed of a plurality of 
novel refractory bricks 17 or 17a formed in accordance with the invention. 
Each checkerwork structure 16 is contained within a unitary refractory 
brick housing 18. In order to provide for the flow of combustion air 
upwardly and hot waste gases downwardly through the regenerators 13 and 
13a, each regenerator is provided with a lower plenum chamber 19 
comprising a longitudinally extending tunnel or passageway, and an upper 
longitudinally extending plenum chamber 20. To this end, each checkerwork 
structure 16 is supported on a plurality of transversely extending and 
longitudinally spaced ceiling supports or arches 21 which support the 
checkerwork structure 16 above a floor 22. The bricks 17 of the 
checkerwork structure 16 are topped off below the level of the series of 
ports 15 and 15a. 
According to this invention, and as illustrated in FIGS. 2 and 3, each 
refractory brick 17 and 17a is a tubular member generally octagonal in 
cross section, having similar top and bottom surfaces 23 and 24, 
respectively, with a longitudinal central passage 25 extending 
therebetween. More specifically, each refractory brick 17 and 17a 
comprises an octagonally shaped body including two pairs of diametrically 
opposed side walls 26 and 26a, respectively, disposed at right angles to 
each other and of uniform wall thickness. Angled or oblique corner 
portions 27 extend between and join the adjacent longitudinal edges of the 
side walls to one another. It should be noted that the two pairs of walls 
26 and 26a are disposed in a substantially square relation in cross 
section. Preferably, the corner portions 27 are disposed at an angle of 45 
degrees with respect to the adjacent walls 26 and 26a. Also, the width of 
each of the parallel side walls 26 and 26a is about two and one half times 
greater than the width of the angled corner portions 27. 
As illustrated in FIG. 2, the walls 26 and 26a and the corner portions 27 
of that embodiment are of substantially uniform thickness, with the inner 
surfaces thereof defining an octagonally shaped longitudinal central 
passage 25. On the other hand, the central passage of the embodiment 
illustrated in FIG. 3 is tetragonal in cross section, that is, the four 
inner surfaces of the walls 26 are connected by arcuate portions 28 to 
define the central passage 25. 
The top and bottom surfaces 23 and 24, defined by the opposed ends of the 
walls 26, 26a and the corner portions 27, are disposed perpendicularly 
with respect to the central passage 25. As illustrated in FIG. 2, the top 
and bottom surfaces 23 and 24 of the walls 26 and 26a each include a 
concave portion or recess 23a and 24a, respectively. The recesses 23a and 
24a are disposed in longitudinal alignment with one another and define 
aligned elevated corner portions 23b and 24b on top and bottom surfaces 23 
and 24, respectively. As will be hereinafter described, in stacking the 
bricks to assemble the checkers. The elevated portions 23b and 24b are 
adapted to cooperate with corresponding recessed and/or elevated portions 
of the bricks 17 in adjacent courses. It should be noted that the recessed 
portions 23a and 24a, as well as the elevated corner portions 23b and 24b 
are substantially uniform in size and shape, and are of such configuration 
that the recessed portions are adapted to receive the elevated portions in 
an interlocking relationship with the bricks set in a staggered 
arrangement as well be hereinafter described. To that end each of the 
recesses 23a and 24a comprises a pair of sloping planar end walls 23c or 
24c, interconnected by a planar base 23d or 24d, respectively. The bricks 
may also be laid up with adjacent courses vertically aligned or 
horizontally offset with the corner portions 23b and 24b stacked one upon 
another. Thus, it will be apparent the aforedescribed exterior 
configuration of the brick 17 permits a number of bricks to be arranged in 
various patterns of stacked courses of checkerwork structures heretofore 
not possible by known prior art bricks. 
One pattern 16a of checkerwork structure, known as a closed setting, is 
illustrated in FIGS. 4 and 5 and includes a number of parallely arranged 
horizontal rows 29 of bricks 17, with the bricks in alternate rows being 
offset one from another (see FIG. 4). Also, the checkerwork structure 
includes a number of vertically disposed courses or layers 30a, 30b and 
30c of rows 29 (see FIG. 5), with the rows 29 of bricks 17 of one layer 
being staggered relative to the bricks 17 in an adjacent layer. In this 
pattern, vertically extending passages 31 (FIG. 4) are formed in the 
checkerwork, the passages 31 being defined, in alternate layers or 
courses, by the central passage 25 in the tubular bricks 17 of one layer, 
and the exterior surfaces of the walls 26 and/or 26a of four adjoining 
bricks 17 in the adjacent layer of the parallel rows 29 of bricks 17. 
Also in this pattern of checkerwork structure 16a, cross passages 32 
through the bricks are defined by cooperating depressed portions 23a and 
24a of bricks 17 in adjacent layers, permitting gas flow between the 
vertical passages 31. This cross-flow of gases creates a turbulence and 
equalizes pressure in the flow of both the combustion air and hot waste 
gases, resulting in increased heat exchange between the bricks and the 
gases. In order to achieve still greater cross flow of the combustion air 
and exhaust gases, the novel bricks of the invention may be set in a 
so-called open setting (not shown) wherein the bricks 17 are omitted in 
alternate parallel rows 29 in either or both directions. There will thus 
be created transversely extending passageways having a cross-sectional 
area comparable to the dimensions of the omitted bricks. 
Another pattern 16b of checkerwork structure is shown in FIGS. 6 and 7. In 
accordance with this pattern, the adjacent layers 30a, 30b and 30c are 
interlocked to each other by staggering one layer or course of bricks 
relative to the next so that the top, elevated portion 23b of one layer of 
bricks 17 is received in and cooperates with the bottom, recessed portions 
24a of the adjacent layer of bricks (see FIG. 7). More particularly, the 
elevated portions 23b and 24b and associated sloping walls 23c and 24c 
engage and rest upon the bases 23d or 24d and their associated sloping 
walls. In this pattern, gas flow turbulence is enhanced and refractory 
contact area is increased by separation of the vertical passages 31 into 
two parts 31a and 31b due to the staggered setting of alternate courses of 
bricks. 
It will, of course, be understood that while the aforedescribed settings of 
the novel brick have been individually described and illustrated as 
utilized in a particular checker structure, the closed, open and 
interlocked setting arrangements may be combined in various combinations 
as desired for specific installations. 
It is to be understood that the forms of the invention herewith shown and 
described are to be taken as illustrative embodiments only of the same, 
and that various changes in the shape, size and arrangement of the parts 
may be resorted to without departing from the spirit of the invention.