Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02467098 2008-01-23
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REFRACTORY CERAMIC CHECKER BRICK
DESCRIPTION
The invention relates to a refractorv checker block such as
is, for example, used for the checker arrangement of
chambers in a glass melting furnace.
Known prismatic refractory hollow blocks of a generic type
are described in AT 406 197 B, which describes the present
state of development. of checker blocks as well as
describing earlier embodiments.
Hollow blocks of the type mentioned, which are also
referred to as chimney bricks or hollow chimney blocks, are
well proven and widely used. The symmetrical design of the
chimney blocks makes it possible to arrange the blocks of
adjacent checker planes so that they are offset in relation
to each other. In this way, an even design of the checker
arrangement and high stability are achieved.
Over time, deposits (slagging) of extraneous particles
which are introduced via the waste gas during heating of
the checker arrangement occur on the walls of the checker
blocks. This necessitates more or less regular cleaining.
In the described design of a checker arrangement made of
conventional chimney blocks, such cleaning is only possible
with difficulty.
In a so-called grate packing, in which cuboid full blocks
are arranged in adjacent planes so as to be offset to each
other by 90 , without further ado there are (horizontal)
through-passages within a "checker plane", which through-
passages make cleaning possible. However, such a grate
packing is associated with a disadvantage in that such a
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checker arrangement has a relatively poor thermal
efficiency and poor mechanical stability.
The invention strives for a symbiosis of the above-
mentioned thermal and mechanical parameters, in other
words, an option for designing a checker arrangement is to
be disclosed that shows how good thermal efficiency as well
as the above-mentioned cleaning option can be achieved
while providing good mechanical stability.
In this endeavour, the invention is based on a conventional
checker brick, as is for example described in DE 29 34 208
C2 or in AT 406 197 B. Such a hollow brick is essentially
rotationally symmetrical as regards its central
longitudinal axis (after rotation by 900, the same
geometrical shape results). Such a block is now modified as
far as its geometrical shape is concerned, to the extent
that it now comprises larger wall sections (wall areas
comprising larger surfaces when compared to the state of
the art). These larger wall sections can be made with
several and/or larger recesses so as to improve the
efficiency and/or to admit cleaning equipment.
Simple dimensional enlargement of the known checker blocks
does not lead to the desired outcome because the basic
checker design would remain unchanged. Furthermore, thermal
efficiency would decrease.
The idea according to the invention provides for the
checker block comprising an essentially rectangular base
(instead of the hitherto essentially square base). The
geometrical shape of the hollow block is to be such that
blocks within a checker plane and in different checker
planes are arbitrarily (statistically) combinable in the
sense of achieving an even checker design or an even
checker density.
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One option of achieving this consists of selecting the
length of the block such that it corresponds to double the
width of the block minus the wall thickness of a wall. Such
a brick is shown and explained in the description of the
figures below.
The following is another design of the geometrical shape of
the block: in a so-called "closed arrangement" of the
blocks in a (regenerator) checker arrangement, the distance
between central longitudinal axes of adjacement blocks in
the longitudinal direction is an integral (even) multiple
of the distance between central longitudinal axes of
adjoining blocks in a transverse direction (perpendicular
to the longitudinal direction). In this type of placement,
one block of one plane is always placed on a wall section
of a block in the plane below it, as will also be explained
in more detail in the description of the figures.
The checker blocks can be arranged side-by-side and
perpendicular in relation to each other in a checker plane.
This applies correspondingly in relation to the arrangement
in a vertical adjacent checker plane, so that overall again
a three-dimensional checker design can be constructed which
is similar to a design made of conventional checker blocks.
There is a further advantage in that the checker blocks
dimensioned in this way can be combined, within one checker
plane, with conventional chimney blocks. In this respect,
reference is made to the description of the figures.
Accordingly, in its most general embodiment, the invention
comprises a refractory checker block with the following
characteristics:
= eight wall sections, abutting at an angle of < 900 in
relation to one another;
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= the wall sections delimit a space which is open at
opposite ends;
= the wall sections provide an upper and lower mutual
placement area;
= the length of the checker block corresponds to an even
multiple of its width, minus one wall thickness;
= the checker block is designed so as to be symmetrical in
relation to a mirror plane which divides the checker
block in longitudinal direction.
Like a conventional checker block, the checker block is
ring shaped, wherein the cross-sectional area of the space
enclosed by the wall sections now however is essentially
rectangular (including the inclined corner areas, it is
octagonal in shape). The waste gas (when heating an
associated regenerator) or the air (for subsequent thermal
absorption) flows through the corresponding hollow spaces
in vertical direction, but it also flows (in horizontal
direction) through the openings formed in the individual
wall sections.
Due to the elongated design, recesses (openings) comprising
a large cross-sectional area, if need be several recesses
side-by-side, can be formed in the large (opposite) side
areas of the checker block.
According to one embodiment, the cross-sectional area of
the recess(es) is at least 15 % of the entire cross-
sectional area of the associated wall section. It can
easily also be > 30, > 35, > 40, > 45, > 50, or even > 60
or > 70 % of the entire cross-sectional area of the
associated wall section.
The recess (through opening) can be designed in the shape
of a borehole. But it can also be open to a placement area
of the checker block, i.e. gate-shaped.
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The large cross-sectional area of the recess in a checker
block according to the invention provides the following
advantages when compared to the state of the art as
mentioned in the introduction:
= It becomes possible, for example by means of lances or
rods, to clean the checker arrangement horizontally.
= By reducing the mass fraction of the checker block, the
surface on which possible extraneous particles can
deposit is also reduced.
= The enlarged openings create increased turbulence of the
air/gases conveyed through, thus increasing the thermal
transmission to the walls.
= Overall, the checker block has a lower weight of unit
volume (kg/m3).
= Because the length and width of the checker block are
matched in the sense of a checker design with even
distribution, the block can also be combined with
"partial-size blocks", such as "half-size blocks" or
"two-cut blocks", as is shown in the figures below.
Basically, any geometry of the recess (opening) is
possible. According to one embodiment, at least one recess
in longitudinal direction of the checker block is of a size
which corresponds to at least 50, 60 or 70 % of the length
of the associated wall area.
The wall sections which extend perpendicular to the wall
sections which extend in longitudinal direction, in other
words the shorter wall sections may comprise recesses as
well.
In a checker block whose length corresponds to
approximately twice its width, it is however expedient if
the cross-sectional area of the recesses in the wall
sections which extend in longitudinal direction are
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approximately twice the size as, at any case greater than,
the cross-sectional area of the recesses in the wall
sections which are perpendicular thereto (in the direction
of the width of the block).
The described geometrical design of the block makes it
possible to take over the inventive idea formulated in AT
406 197 B, namely to provide those wall sections, which
extend between the wall sections running in a longitudinal
direction of the checker block, i.e. perpendicular to those
with a thinner wall thickness. This makes it possible, in
the combined arrangement, to create "columns" (hollow
spaces) also between adjacent checker blocks of a checker
plane, which columns can be used for the purpose of thermal
efficiency in that waste gas/air can also be fed
therethrough.
The respective wall sections may, for example, have a wall
thickness which is reduced by 15 to 35 % when compared to
the thickness of other wall sections.
When designing a complete checker relining arrangement, it
is expedient to form elevations and/or indentations in the
manner of a tongue and groove system along the areas where
blocks are placed so as to be able to provide a safe
mechanical fixture for vertically stacked blocks in
relation to each other. Concerning design options reference
is made to the state of the art mentioned above and being
analogously adaptable.
The new checker blocks can easily be combined with known
checker blocks. Thus, at least one checker plane can be
designed using the described large checker blocks. If a
checker plane above it made from conventional (smaller)
checker blocks is built, this can lead to a lumped load (in
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the corner regions) acting on the wall sections of the
(larger) checker blocks below.
It is thus proposed to shape these checker blocks such that
the geometrical moment of the wall sections which extend in
longitudinal direction be greater (for example: > 50 %
greater) (I = (b = h) 3/12 where b = width, and h = height
of the rectangular cross-section) than the geometrical
moment of the other wall sections, in particular the wall
sections which form the narrow sides of the block. The
following measures are possible:
= Widen the wall thickness.
= Avoid recesses (openings) or reduce their cross-
sectional area.
= Arrange the recess(es) so that in vertical extension of
the expected lumped load, the wall section is free of
any recesses.
Further characteristics of the invention result from the
characteristics of the subclaims as well as the other
application documents.
Hereinafter, the invention is explained in more detail by
means of various embodiments. The description of the
figures contains characteristics which can also be used for
the invention either as such or in any desired
combinations.
The following is shown diagrammatically:
Figure la: a top view of a checker block;
Figure lb: a lateral view of the checker block according
to Figure la;
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Figure ic a further lateral view of the checker block
according to Figure la;
Figure ld: a perspective view of the checker block
according to Figure la;
Figure 2: a perspective partial view of a checker
arrangement with checker blocks according to
Figures la-d;
Figure 3: a top view of a checker plane made of checker
blocks according to Figures la-d;
Figure 4: a top view of a multi-storey design of a
checker arrangement made of different hollow
blocks; and
Figure 5: a perspective partial view of an alternative
design of a checker arrangement.
In the figures, identical components or components having
identical effect are designated by means of the same
reference characters.
The checker block according to Figures la, b is designed as
follows:
It comprises a total of eight wall sections 10.1,
10.2 ... 10.8. The wall sections are parallel in pairs on
opposite sides. The wall sections 10.1, 10.5 extend in
longitudinal direction L. The wall sections 10.3, 10.7
extend perpendicular to the longitudinal direction L, and
thus in "transverse direction" Q. The further wall sections
10.2, 10.4, 10.6 and 10.8 connect the previously described
wall regions 10.1, 10.3, 10.5 and 10.7 in the embodiment
shown in such a way that adjacent wall sections such as
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10.1, 10.2 or 10.5, 10.6 extend at an angle of 45 in
relation to each other.
Overall, this results in an octagonal base, including the
space 12 which is enclosed by the wall areas 10.1,
10.2...10.8, with the horizontal cross-sectional area of
said space 12 also being octagonal. The space 12 is open at
the top and at the bottom (in the direction of the central
longitudinal axis MLA of the block).
The length 1 of the block (in this embodiment 398 mm)
corresponds to twice the width b (in this embodiment 2 x
218 mm) minus one wall thickness (in this embodiment 38 mm)
of one of the walls 10.1, 10.5 which extend in longitudinal
direction L.
With aõclosed arrangement", the distance between the
central longitudinal axes MLA of two blocks adjacent in
longitudinal direction corresponds to twice the distance
between the central longitudinal axes MLAs of two blocks
adjoining in transverse direction.
In the large wall sections 10.1, 10.5, corresponding
recesses 14 are provided which are open to the lower
placement area 16 and are gate-shaped in lateral view
(Figure 1b).
In the embodiment shown, the cross-sectional area of the
recess 14 is only slightly smaller than the cross-sectional
area of the remaining wall section 10.5. In other words,
the cross-sectional area of the recess 14 is approximately
40 % of the theoretical total area of the wall section
10.5.
As is shown in Figure 1c, the narrow wall sections 10.3,
10.7 also comprise recesses 18, however, their cross-
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sectional areas are smaller when compared to those of the
recesses 14 (in this embodiment approx. 25 % smaller).
While on the placement areas 16 of the wall parts 10.1,
10.5, indentations are arranged at a distance from each
other, extending perpendicular to the longitudinal
direction L, on the lower placement area 16 of the wall
sections 10.3, 10.7, indentations in longitudinal direction
L are provided. In the upper placement areas 20 of said
wall parts 10.1, 10.3, 10.5 and 10.7, corresponding
elevations 22 are arranged, with the indentations and
elevations 22 matching so that a positive fit results when
the checker blocks are stacked.
In relation to the plane indicated by the line Q - Q, the
block is designed so as to be a mirror inversion, parallel
to the central longitudinal axis MLA.
Checker blocks of the type shown can be made from any
desired refractory materials, depending on the application
area. To this extent there are no differences compared with
conventional checker blocks. This is also true in relation
to the method for producing the checker blocks.
Figure 2 shows an exemplary checker arrangement made of
blocks T according to the invention, in combination with
conventional hollow blocks K.
Figure 3 shows the basic design of a checker plane made of
blocks T according to the invention, with said blocks T
being arranged offset in relation to each other "in lines
and columns" so as to achieve an even checker density.
Adjacent blocks T within one plane abut along the angled-
off corner regions 10.2, 10.4, 10.6 or 10.8. Four adjoining
blocks (in Figure 3 these are T1, T2, T3, T4) enclose a
space R, whose cross-sectional area corresponds
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approximately to the cross-sectional area of the space 12
of each block T.
Figure 4 shows a design which is analogous to that
according to Figure 3, except that there are blocks in
different checker planes, wherein in each case two adjacent
blocks cover each other in a wall section, as is also shown
in Figure 2.
In part of the checker arrangement shown in Figure 4 (and
likewise in Figure 2), the blocks according to the
invention have been replaced by conventional blocks of the
design according to DE 29 34 208 C2 or AT 406 197 B
respectively. Due to the geometrical shape of the checker
blocks according to this invention, these smaller formats
can be placed onto the larger formats without any problem.
Likewise, again, checker blocks according to the invention
can be placed onto conventional checker blocks, in a plane
above.
In particular Figures lb, d and 2 show that the described
geometrical shape of the blocks provides a horizontal
cleaning option along the channels formed by the openings
14, even in a closed way of placing the blocks.
Figure 5 diagrammatically shows the following checker
arrangement:
In a checker plane A, checker blocks similar to those in
Figures la-d are arranged, except that their wall sections
10.1, 10.3, 10.5 and 10.7 are closed so as to increase the
geometrical moment of inertia of the wall sections.
In the plane above (plane B), there are conventional
checker blocks T which are essentially supported on the
checker block below them by their four corners. This
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becomes possible as a result of the solid walls 10.1, 10.3,
10.5 and 10.7.
