Title of Invention

"INDUSTRIAL KILN"

Abstract

Industrial kilns that are designed for example according to the principles of the Maerz regenerative kiln include a multilayer inner wall (4) that is curved circumferentially and is exposed to circulating hot gases. At least the convex outer lining layer (11) thereof is constructed from interlocking fire-resistant shaped bricks (11). In order to prevent the build-up of damaging thermal stresses in the convex lining layer (13) when the kiln is heated, this layer is interrupted in the circumferential direction by at least one compensation area (15). This area includes two fire-resistant concrete shaped bricks (20,21) that are poured onto adjacent shaped bricks (11) and are on either side of an expansion joint (19).

Full Text

The invention relates to an industrial kiln having a multilayer inner wall that is curved circumferentially, wherein at least the lining layer, which is convex in shape, includes fire-resistant shaped bricks that engage with each other. Various kihi designs, e.g. annular shaft kilns or parallel shaft regenerative kilns as built by Maerz, include annular kiln areas which are delimited inwardly by an inner wall that is supported at the bottom or is suspended. When fiiel gases come into contact with the wall, it heats up and the circumferentially enclosing, convex outer layer expands so that the outer shaped bricks thrust outwards, pressing against each other. Since this does not occur uniformly, stresses are created that cause the jointed structure of the shaped bricks to loosen until some shaped bricks may break. On the other hand, as the installation cools down following an interruption in operation, cracks are formed due to shrinkage, and these are then filled with dust, so that when the kiln is heated agaia later the effects described earlier occur yet more severely and the damage to the jointing of the shaped bricks is increased correspondingly. In this manner, damage can reach such a level that at least the convex outer layer of the inner wall needs to be replaced after just a few heating and cooling cycles. On the other hand, the thermal expansions cause bracing which stabilises the jointing structure in the inner, concave lining layer. The task imderlying the present invention is to avoid the drawbacks described, and thus suggest an industrial kihi whose fire-resistant lining is more resilient and therefore offers better operating safety. This task is solved according to the invention in that the convex lining layer formed by shaped bricks is interrupted in the circumferential direction by at least one compensation area made from fire-resistant concrete shaped bricks and including an expansion joint, wherein the fire-resistant concrete shaped bricks are poured onto the adjacent shaped bricks so that they engage in the interlocking profile of the blocks and are anchored to an inner layer of the inner wall with concrete anchors. An industrial kiln having a multilayer inner wall (4) that is curved circumferentially, wherein at least the convex lining layer (13) has fire-resistant, interlocking shaped bricks (11), characterised in that the convex lining layer (13) formed by shaped bricks (11) is interrupted in the circiimferential direction by at least one compensation area (15) formed by fire-resistant concrete shaped bricks (20,21; 30,31) and containing an expansion joint (19; 28,29), wherein the fire-resistant concrete shaped bricks (20,21; 30,31) are poured onto the adjacent shaped bricks (11), so that they interlock in the toothed profile thereof and are anchored to an inner layer (5) of the inner wall (4) by concrete anchors (22,23). Advantageous variants of the invention are described in the dependent claims, and are explained in the following description with reference to the drawing. In the drawing: Fig.l is an axial cross-section through an area of a regenerative parallel shaft kiln with a cylindrical inner wall, Fig.2 is a radial cross-section through the cylindrical inner wall of the kiln area along line II-II of Fig.l, Fig.3 is an enlarged section of the kiln area of Fig.l, Fig.4 is a side view of an area of the inner wall in the direction of arrow IV in Fig.3, Fig.5 is a partial cross-section through the inner wall along line V-V of Fig.3 and Fig.6 and Fig.7 are radial cross-sections responding to Fig.5 with two additional embodiments of a compensation area. As is known from the amply documented descriptions of shaft kilns constructed in the manner or Maerz, each of two or more parallel kiln shafts 1 has an annular channel 2, into which the fiiel gases flow in the direction of arrows 3, to pass into a second kiln shaft (not shown) that is operated regeneratively. As a result, hot gases at temperatures reaching 1000° C when burning lime circulate over cylindrical inner wall 4, which delimits annular channel 2 on the inside. The suspended arrangement of inner wall 4, shown as an exemplary embodiment, has a metallic, inner support layer 5 with cooling channels 6 through which air is passed. The bottom end thereof is conformed as a holder 7 for a bottom thrust ring 8 that is poured from fire-resistant concrete. Inner support layer 5 is protected on both sides by insulating layers 9, 10. The outer enclosure of inner wall 4 is provided in each case by a wear lining made from fire-resistant shaped bricks 11,12, which thus form a lining layer that is outwardly convex and inwardly concave 13,14. A suspended design of such kind has seldom been used for inner wall 4, because its conventional construction meant that there was a risk that hot gases might come into contact with the metallic support layer 5 through a damaged convex lining layer 13, and thus destroy it. However, the present invention means that the suspended variant, which has advantages over the bottom-supported design, may be implemented without this danger. When the kiln is commissioned, progressive warming causes thermal expansion, which produces a stabilising compression of fire-resistant shaped bricks 12 provided in inner, concave lining layer 14, and at the same time causes convex lining layer 13 to expand, which would lead to the loosening of the jointing structure among fire-resistant shaped bricks 11 described in the introduction but for the means according to the invention, which will be described in the following. In order to prevent damage to the cinder block jointing due to the expansion that occurs in outer, convex lining layer 11 when the kiln is heated, lining layer 11 is interrupted by at least one compensation area 15-18, of which four are provided, distributed evenly about the circumference as illustrated in Fig. 2. As shown in Figs. 4 and 5, each compensation area 15 to 18 has two concrete shaped bricks 20,21 on either side of an expansion joint 19, which are connected circumferentially in positive locking form with shaped adjacent shaped bricks 11 and are also secured to metallic support layer 5 via multiple e.g. bifurcated concrete anchors 22,23. They have a flat cross-section, so that they are pliant in one direction only and are rigid in the direction perpendicular thereto, vdth the effect that they block concrete shaped bricks 20,21 in their vertical position. Since they too have a positive locking arrangement with shaped bricks 11, which are shaped to interlock with each other in the manner of gear teeth, concrete shaped bricks 20,21 of the four compensation areas 15 to 18 thus secure the convex or curved lining sectors 24 to 27 that extend in a 90° therebetween on inner, metallic support layer 5 in the manner of a flexible thrust bearing, thereby preventing displacement and local overloading of the lining. The degree of flexibility of compensation areas 15 to 18 is determined by the width of expansion joint 19. This width of the expansion joints 19 is preferably is designed such that they are completely closed at least by the time the kiln reaches its operating temperature, or that they also enable the build-up of pressure in lining sectors 24 to 27, so that this pressure is released first as the kiln cools down, before shrinkages and relative movements in the jointing structure of shaped bricks 11 become possible. As shown in the exemplary embodiment in Fig.6, two expansion joints 28,29 are provided that are offset circumferentially in such manner that the two concrete shaped bricks 30,31 interlock with each other, thereby lending the expansion joint a labyrinthine shape. In exemplary embodiments Fig. 5 and Fig. 6, concrete shaped bricks 20,21 or 30,31 of compensation area 15 have the same radial width as fire-resistant shaped bricks 11 of the convex lining layer 13, so that the associated concrete anchors 22,23 extend through the inwardly adjacent insulating layer and may accordingly perform an obstructed bending movement therein. In the embodiment shown in Fig.7, a projection 34,35 of concrete shaped bricks 32,33 enclosing a part of concrete anchors 22,23 extends as far as the metallic support layer 5, thus enclosing a cavity 34 that is filled with insulating material. These projections 34,35 serve to stiffen concrete anchors 22,23, so that greater compression stresses then in the embodiments according to Figs. 5 and 6 may be built up in lining sectors 24 to 27 when expansion joint 19 is closed. We Claim: 1. An industrial kiln having a multilayer inner wall (4) that is curved circumferentially, wherein at least the convex lining layer (13) has fire-resistant, interlocking shaped bricks (11), characterised in that the convex lining layer (13) formed by shaped bricks (11) is interrupted in the circumferential direction by at least one compensation area (15) formed by fire-resistant concrete shaped bricks (20,21; 30,31) and containing an expansion joint (19; 28,29), wherein the fire-resistant concrete shaped bricks (20,21; 30,31) are poured onto the adjacent shaped bricks (11), so that they interlock in the toothed profile thereof and are anchored to an inner layer (5) of the inner wall (4) by concrete anchors (22,23). 2. The kiln as claimed in claim 1, wherein the expansion joint (28, 29) is labyrinthine in shape. 3. The kiln as claimed in claim 1 or 2, wherein the width of the expansion joint (19; 28, 29) when the kiln is cold is such that it is fully closed at the operating temperature of the kiln. 4. The kiln as claimed in claim 3, wherein the size of the expansion joint (19; 28,29) is such that it is closed at the operating temperature of the kiln and the shaped bricks (9) of the convex outer layer (11) are placed under compression stress that operates in the circumferential direction of this outer layer. 5. The kiln as claimed - in any of claims 1 to 4, wherein a compressible insulating material is arranged inside the expansion joint (19; 28, 29). 6. The kiln as claimed in any of claims 1 to 5, wherein an inner support layer (5) of the inner wall (4) is made from metal, and concrete anchors (22,23) that are enclosed in the poured concrete shaped bricks (20,21; 30,31) surrounding the expansion joint (19; 28,29) are secured to the metallic support layer (5). 7. The kiln as claimed in any of claims 1 to 6, wherein the inner wall (4) is suspended in the kiln, wherein the metallic support layer (5) is conformed as a wall support by a bottom holder (7). 8. The kiln as claimed in any of claims 1 to 7, wherein the radial width of the concrete shaped bricks (20,21) of the at least one compensation area is equal to that of the shaped bricks (11) in the convex lining layer (13). 9. The kiln as claimed in any of claims I to 7, wherein the concrete shaped bricks (32,33) have an inwardly directed projection (34,35) that encloses at least one concrete anchor (22,23), and with which they extend as far as the metallic support layer (5). 10. The kiln as claimed in any of claims 6 to 9, wherein the concrete anchors in at least one area adjacent the metallic support layer (5) are designed to be pliant or articulated in the circumferential direction of inner wall (4) and are rigid in the direction perpendicular thereto.

Documents:

1311-del-2005-abstract.pdf

1311-del-2005-assignment.pdf

1311-DEL-2005-Claims-(12-01-2012).pdf

1311-DEL-2005-Claims-(14-12-2011).pdf

1311-del-2005-claims.pdf

1311-DEL-2005-Correspondence Others-(12-01-2012).pdf

1311-DEL-2005-Correspondence Others-(26-08-2011).pdf

1311-DEL-2005-Correspondence-Others-(14-12-2011)..pdf

1311-DEL-2005-Correspondence-Others-(14-12-2011).pdf

1311-del-2005-correspondence-others.pdf

1311-del-2005-description (complete).pdf

1311-del-2005-drawings.pdf

1311-del-2005-form-1.pdf

1311-del-2005-form-18.pdf

1311-del-2005-form-2.pdf

1311-DEL-2005-Form-3-(26-08-2011).pdf

1311-del-2005-form-3.pdf

1311-del-2005-form-5.pdf

1311-DEL-2005-GPA-(12-01-2012).pdf

1311-DEL-2005-GPA-(14-12-2011).pdf

1311-del-2005-gpa.pdf

1311-DEL-2005-Petition-137-(14-12-2011).pdf

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