Grate blocks for combustion grates

Abstract

The present invention relates to a grate block (10) for a combustion grate, in which successive grate blocks are arranged one above the other in a stepped manner and are configured to transport the combustion material by thrusting relative to one another. The grate block (10) has a block body (12) having an upper wall (14) forming a support surface (16) along which the combustion material is transported, and a front wall (20) forming a thrust surface (22), each of which has a first air supply opening (25) formed for supplying air onto the combustion grate by a first air supply passage (27), and a lower support edge (23) defined to contact the support surface of an adjacent grate block in the thrust direction S. Further air supply passages (38) extending therethrough and oriented obliquely relative to the direction of the first air supply passages are formed in the top wall (14) and the front wall (20) for cooling the top wall (14) and the front wall (20).

Description

[Technical field]

[0001] The present invention relates to a grate block for a combustion grate according to the preamble of claim 1. The present invention further relates to a combustion grate comprising at least one such grate block. The present invention further relates to the use of said combustion grate for the incineration of waste, as well as to a waste incineration plant comprising such a combustion grate. [Background technology]

[0002] Grates for industrial-scale incineration of waste materials have been known to the person skilled in the art for a long time. Such grates can be in the form of advancing combustion grates, which include a moving part suitable for carrying out a stoker stroke, for example. The material to be burned is transported from the inlet end of the grate to the outlet end and is burned during this time. In order to supply the grate with the oxygen required for combustion, a corresponding air supply is provided through the grate, through which air, also called primary air, is introduced.

[0003] Frequently used grates are so-called stepped grates, which comprise grate blocks arranged next to one another to form respective grate rows, the grate block rows being arranged one above the other in a stepped manner, so that in the case of so-called forward grates, the front ends of the grate blocks, seen in the thrust direction, rest on the support surfaces of the adjacent grate blocks in the transport direction and move over these support surfaces with a corresponding thrust movement.

[0004] In the case of so-called retreating grates, the grate blocks are arranged rotated by approximately 180° in relation to the advancing grates, as viewed in the transport direction of the fuel. In the case of retreating grates, the front ends of the grate blocks, as viewed in the thrust direction, are therefore supported on the support surfaces of the preceding grate blocks. In contrast to the advancing grates, in the case of retreating grates, the thrust direction is thus opposite to the transport direction resulting from the inclination of the retreating grate.

[0005] A combustion grate formed as a stepped grate and a grate block for such a combustion grate are described, for example, in the document DE 10 200 45 133. This document relates to an air-cooled grate block. In particular, the grate block described in DE 10 200 45 133 has a block body formed as a cast part with an upper wall forming a support surface for the waste to be treated and a front wall forming a thrust surface. In the lower region of the front wall a base is formed which is designed to be supported in a thrust direction on the support surface of the adjacent grate block in such a way that it can be advanced, whereas in the front wall an air supply opening for introducing air is arranged.

[0006] The grate blocks are generally subjected to a relatively large amount of wear due to the fuel transported through them. The wear is particularly large precisely in the region of the frontmost end of the support surface, where the fuel is dropped from the support surface of the grate block via a corresponding drop edge onto the support surface of the following grate block. This also leads in particular to erosion of the air supply openings arranged below the edge. This can undesirably impair the controlled air supply to the combustion bed located above the combustion grate.

[0007] The grate blocks are furthermore exposed to very strong thermal loads, in particular due to the high temperatures during combustion or in the firebox, and during normal operation of the combustion grate, these thermal loads are particularly high in the region of the support surface, but the combustion material located on the grate blocks acts to some extent to separate.

[0008] If the combustion products are distributed unevenly on the combustion grate and only a thin separation layer forms, or if there is no such layer at all, very high loads occur. The thermal loads promote wear corrosion and chemical reactions taking place on the support surface, which further damages the support surface. This ultimately shortens the useful life of the grate block. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2016 / 198119 Summary of the Invention [Problem to be solved by the invention]

[0010] The problem to be solved according to the present invention is therefore to provide a grate block of the type mentioned at the outset, which has a long service life and in which corrosion of the support surfaces, in particular at the frontmost end of the grate block, is minimized. [Means for solving the problem]

[0011] This problem is solved by a grate block as defined in independent claim 1.

[0012] Advantageous embodiments of the grate block according to the invention are reflected in the dependent claims. Effect of the Invention

[0013] According to claim 1, the invention relates to a grate block for a combustion grate, in which successive grate blocks are arranged one above the other in a stepped manner and are designed to reconfigure and transport the combustion product by thrust movements performed relative to one another, i.e. by relative movements between the grate blocks. Such a combustion grate is also called a stepped grate, as mentioned at the beginning.

[0014] Furthermore, the grate block has a block body, which is preferably formed as a cast part. Usually, the block body is formed mainly in the form of an elongated rectangular parallelepiped with a longitudinal axis L.

[0015] The block body has an upper wall portion defining a support surface extending parallel to the longitudinal axis L along which the material to be combusted is transported, the support surface defining a material side of the upper wall portion.

[0016] The forwardmost end of the support surface, as viewed in the thrust direction S, forms an edge via which the support surface descends into the thrust surface formed by the front wall, which thus forms the transition between the upper wall and the front wall.

[0017] The side of the top wall opposite the support surface and the side of the front wall opposite the thrust surface define the cooling air side of the block body.

[0018] The thrust direction S refers to the direction in which the fuel is pushed away from the thrust face of the grate block. Typically, the thrust direction S is parallel to the longitudinal axis L.

[0019] The transport direction T defines the direction of movement of the combustion material from the inlet to the outlet of the combustion grate. The transport direction T is mainly caused by the inclination of the combustion grate.

[0020] The front wall has a first air supply port formed for supplying air onto the combustion grate by a first air supply passage extending perpendicularly or obliquely to the thrust plane as viewed in longitudinal section.

[0021] The term "air" then includes so-called primary air, which is supplied to the combustion grate or to the combustion bed above the combustion grate. The primary air primarily serves to combust the fuel, but also to cool the grate blocks of the combustion grate.

[0022] Furthermore, in its lowermost region, the front wall is formed in the form of a base, which is designed to bear on the bearing surface of the adjacent grate block in the thrust direction.

[0023] According to an advantageous embodiment, the first air supply passages extend, in a longitudinal section, at an angle α to the area of ​​the thrust surface directly bordering the respective first air supply opening. α is between 90° and 135°, preferably between 95° and 125°, particularly preferably between 100° and 120°, and in most cases preferably between 105° and 115°. The angle α is measured counterclockwise between the longitudinal axis of the respective first air supply passage and the thrust surface. This ensures an optimal supply of air to the combustion grate or to the combustion bed above the combustion grate. This contributes to a very high degree of burning off of the combustion material. The relevant section of the first air supply passage for determining the angle α is the section immediately before the outlet of the respective first air supply passage from the front wall.

[0024] In the case of an advantageous embodiment in which the grate block according to the invention is provided for an advancing grate, the base is therefore supported on the following grate block or on its support surface in the transport direction T of the fuel. However, it is also conceivable that the grate block according to the invention is provided for a retreating grate. In such a case, the base is supported on the preceding grate block or on its support surface in the transport direction T of the fuel.

[0025] At least the lower support edge of the thrust surface is arranged in a plane E which extends approximately perpendicular to the longitudinal axis L. In this regard, it is conceivable that the surface arranged in the lowermost region of the front wall, the lower end of which is formed by the lower support edge, is arranged in plane E. However, it is also conceivable that only the line described by the lower support edge is arranged in plane E.

[0026] According to the invention, a further air supply passage extending through the top wall and the front wall and oriented obliquely with respect to the direction of the first air supply passage is provided for cooling the top and front walls. The further air supply passage forms further air supply openings in the top wall, i.e. in the support surface, and in the front wall, i.e. in the thrust surface. This makes it possible to ensure that the distribution of air for cooling the top and front walls is optimized. As a result, the heat is better conducted away, so that the top and front walls are exposed to less corrosion.

[0027] In an advantageous embodiment, the upper and lower walls are thickened in the region where they abut against one another as a wall thickening in cross section, which in the regions of the grate block that are subject to particularly high wear can increase the service life of the grate block, since it can withstand significantly higher wear.

[0028] In a particularly advantageous embodiment, the wall thickening is formed in such a way that, in a longitudinal section, the edge is offset forward relative to the plane E in the thrust direction S. In other words, the region of the thrust face in which the first and possibly further air supply openings are arranged is offset backward relative to the edge, as viewed along the longitudinal axis L and in the thrust direction S. As the edge is offset forward relative to the plane E along the longitudinal axis L and in the thrust direction S, the first and possibly further air supply openings formed below the edge are at least partially protected. An additional advantage of such an arrangement is that air can more easily flow out through the first and further air supply openings, which leads to better cooling of the front wall.

[0029] In an advantageous embodiment, the wall thickening is curved in cross section, for example in the form of a bead. The curved design of the wall thickening ensures that the combustion products can be transported unhindered through the grate block, i.e. without being blocked by sharp irregularities.

[0030] The concept of thickening the upper or front wall can be understood as having a greater wall thickness in the area of ​​the upper or front wall where it is thickened than in the area immediately surrounding the thickened portion.

[0031] The wall thickening can absorb additional heat during operation of the grate block due to the additional amount of material forming the wall thickening. On the one hand, the wall thickening allows a longer service life of the grate block as a result, since the thickened upper or front wall resists corrosion longer. On the other hand, however, the corrosion of the wall thickening can increase due to strong thermal loads. A further optimization of the grate block therefore consists in optimizing the cooling of the wall thickening.

[0032] In an advantageous embodiment, the further air supply passage is arranged in the wall thickening, i.e. the further air supply passage extends through the wall thickening. Such an arrangement of the further air supply passage and the corresponding further air supply openings ensures better cooling of the wall thickening by air and thus reduces its corrosion.

[0033] However, the further air supply passages can also be arranged only in the top wall, i.e. above the edge of the top wall. Since wear corrosion occurs mainly on the support surfaces, it is advantageous if the wall thickening is formed primarily in the top wall in the region where the top wall and the front wall abut against one another. Such an arrangement of the further air supply passages thus allows for optimized cooling of the wall thickening.

[0034] In an advantageous embodiment, the further air supply passages extend, in the longitudinal section, at an angle β to the longitudinal axis L of the block body, the angle β being between 10° and 60°. The angle β is measured counterclockwise to the longitudinal axis L. Due to the further air supply passages extending obliquely to the longitudinal axis L of the block body, the further air supply passages are longer than if they extended parallel to the longitudinal axis L. As a result, the air flowing through the further air supply passages can generate an efficient cooling effect.

[0035] Advantageously, the angle β is between 15° and 50°. The angle β is selected in such a way that the slag resulting from the combustion of the fuel material falls as little as possible through the other air supply passages and causes blockages, thereby ensuring reliable cooling of the grate block.

[0036] In an advantageous embodiment, a first group of the other air supply passages is formed in a first plane extending at a first angle β1 to the support surface of the block body. Furthermore, a second group of the other air supply passages is formed in a second plane extending at a second angle β2 to the support surface of the block body. The first angle β1 is between 10° and 35°, preferably between 10° and 20°, and the second angle β2 is between 35° and 60°, preferably between 40° and 50°. By dividing the other air supply passages into several groups and distributing them in several planes, it is ensured that the air flowing through the other air supply passages produces an efficiently distributed cooling effect around these planes. This allows the service life of the grate block to be increased.

[0037] In an advantageous embodiment, the first group of further air supply channels and the second group of further air supply channels are formed parallel to one another. Advantageously, the first group of further air supply channels and the second group of further air supply channels are formed parallel to a longitudinal plane P which includes the longitudinal axis L at right angles to the support surface. An additional advantage of such an arrangement is that the further air supply channels are easier to manufacture.

[0038] In an advantageous embodiment, the other air supply passages are distributed in the first and / or second plane at equal intervals over the entire width of the grate block, which ensures that the air flowing through the other air supply passages produces a homogeneous cooling effect around these planes. Thus, the distribution of stresses during operation of the grate block, which is caused by the heat distribution, is also homogeneously distributed in the first and second planes, and the formation of cracks in the grate block is minimized over its entire width. This increases the service life of the grate block.

[0039] In an advantageous embodiment, each one of the other air supply ducts, possibly one of the first group and one of the second group, and one of the first air supply ducts are arranged in one and the same plane, which runs parallel to the longitudinal section P. Such an arrangement of the first and other air supply ducts ensures that stresses during operation of the grate block are also homogeneously distributed in the longitudinal section, which minimizes the formation of cracks over its entire width.

[0040] In an advantageous embodiment, the further air supply passages are distributed symmetrically with respect to a longitudinal symmetry plane of the grate block, which runs perpendicular to the support surface. A further advantage of such an arrangement is that the further air supply passages are easier to manufacture.

[0041] The number of air supply passages and other air supply passages is calculated to be proportional to the width and wall thickness of the grate block in order to optimally cool the grate block.

[0042] In an advantageous embodiment, the further air supply passage has a constant cross-sectional area over substantially the entire length of the further air supply passage, in particular a cross-sectional area of ​​40 mm 2 ~100mm 2 The diameter is selected so that as little as possible of the slag resulting from the combustion of the fuel material falls through the other air supply passages and causes blockages. This ensures reliable cooling of the grate block. The cross section is 80 mm for optimal results. 2 It is advantageous if

[0043] In an advantageous embodiment, the further air supply passages are designed over their entire length so as to continuously widen from the combustion product side to the cooling air side, the ratio of the cross-sectional area of ​​the further air supply passage on the combustion product side to the cross-sectional area of ​​the further air supply passage on the cooling air side being between 1:1.2 and 1:2.5, preferably 1:2.25. The cross-sectional area of ​​the further air supply passage on the combustion product side is measured in the support or thrust plane and corresponds to the cross-sectional area of ​​the further air supply opening. The cross-sectional area of ​​the further air supply passage is measured at its end located on the cooling air side. By designing the further air supply passages in this way, it is possible to easily remove the combustion residues that have entered the further air supply passage. The combustion residues are thus pushed further into the further air supply passage in the direction of the cooling air side by the combustion products located on the grate block and are released as the further air supply passage widens. This makes it possible to avoid clogging of the air supply.

[0044] According to a further aspect, the invention additionally relates to a combustion grate comprising at least one of the grate blocks described above.

[0045] Furthermore, the invention relates to the use of said combustion grate for the incineration of waste, as well as to a waste incineration plant comprising such a combustion grate. The invention is illustrated by the accompanying drawings, in which: [Brief description of the drawings]

[0046] [Figure 1] FIG. 1 is a perspective view showing a grate block according to the present invention. [Diagram 2] FIG. 2 is a longitudinal sectional view of the grate block of FIG. 1 taken along the sectional plane II-II shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view of the grate block of FIG. 1 taken along the section plane III-III shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] 1, the grate block 10 has a block body 12 formed as a cast part. The block body is formed substantially in the form of an elongated rectangular parallelepiped having a longitudinal axis L.

[0048] The block body 12 has an upper wall 14. The upper wall 14 defines a support surface 16 extending parallel to the longitudinal axis L, along which the product is transported, the support surface defining the product side of the upper wall 14. The frontmost end of the support surface 16, as viewed in the thrust direction S, defines an edge 19, via which the support surface 16 descends towards a thrust surface 22 defined by a front wall 20. The side of the upper wall 14 facing away from the support surface and the side of the front wall 20 facing away from the thrust surface 22 define the cooling air side of the block body 12.

[0049] In the embodiment shown, the support surface has a first support surface area 16a and a second support surface area 16b. However, the first support surface area 16a is arranged offset upwards with respect to the second support surface area 16b and is connected to it via a chamfered transition 17.

[0050] Opposite the front wall 20, the block body 12 has a rear wall 24. The rear wall is provided with at least one hook 26 by means of which the grate block 10 can be hooked into the block holder tube. A central web 29 is further arranged on the underside of the grate block 10 facing away from the support surface 16.

[0051] Laterally, the grate blocks 10 are each shaft It is partitioned by side walls 28a, 28b extending in the direction L.

[0052] Within the combustion grate, the grate blocks 10 are supported on the following grate blocks in the thrust direction S. For this purpose, the lowermost region of the front wall 20 is formed in the form of a block 34, which is provided to be supported on the support surface of the adjacent grate block in the thrust direction S. The lowermost region, including the lower support edge 23 of the thrust surface formed by this region, is located in a plane E which extends approximately perpendicular to the longitudinal axis L.

[0053] Furthermore, the grate block 10 is formed with a thickened wall in the region where the upper wall portion 14 and the front wall portion 20 abut against each other. Specifically, the thickened wall portion 40 is formed to be curved on the combustion material side of the upper wall portion 14 when viewed in vertical section.

[0054] The edge 19 formed by the wall thickening 40 is in the embodiment shown offset forward relative to the plane E along the longitudinal axis L and in the thrust direction S. The distance D between the edge 19 and the plane E is approximately 25 mm.

[0055] Thus, in the illustrated embodiment, the second support surface region 16b first extends substantially in one plane and then descends into a curved region which extends to the forwardmost end of the support surface 16 as seen in the thrust direction S.

[0056] The edge 19 formed by the frontmost end of the support surface 16 is here located below the plane of the second support surface area 16b. A thrust surface 22 starts via the edge 19. The thrust surface first extends rearwardly relative to the edge 19 and then extends into the plane E.

[0057] As is clear from Figures 2 and 3, the front wall 20 has two first air supply openings 25. Each first air supply opening is formed by a first air supply passage 27 extending through the front wall 20. Here, the first air supply passage 27 opens into a recess in the front wall 20 formed by the wall thickening 40 and the plane E. The first air supply openings 25 are located below the wall thickening 40 in Figure 1 and cannot be seen. Through the first air supply passages 27, primary air is supplied to the combustion grate or to the combustion bed above the combustion grate.

[0058] Furthermore, the first air supply openings 25 are offset rearwardly relative to the edge 19 along the longitudinal axis L and in the thrust direction S by a distance d of approximately 12 mm in the specifically illustrated embodiment.

[0059] In the grate block shown in FIG. 2, the first air supply passages 27 extend, in longitudinal section, at an angle α of approximately 110° to the area of ​​the thrust face 22 which directly borders the respective first air supply opening.

[0060] In addition, grate blocks 10 has a further air supply passage 38 arranged in a wall thickening 40 extending through the upper wall 14 and oriented obliquely with respect to the direction of the first air supply passage 27 for cooling the upper wall 14. The further air supply passage 38 forms a further air supply opening 35 in the wall thickening 40.

[0061] In the illustrated embodiment, a first group of two further air supply passages 38 is formed in a first plane G1 extending at a first angle β1 relative to the support surface 16. Furthermore, a second group of two further air supply passages 38 is formed in a second plane G2 extending at a second angle β2 relative to the support surface 16. The first angle β1 is 15° and the second angle β2 is 45°. For clarity, the angles β1 and β2 in FIG. 2 are shown relative to the longitudinal axis L. The longitudinal axis L extends relative to the support surface 16.

[0062] As shown in FIG. 3, the two first air supply passages 27 and the two other air supply passages 38 are arranged in pairs and extend perpendicular to the support surface of the grate block. 10 are distributed symmetrically with respect to the longitudinal plane of symmetry P.

[0063] Furthermore, the two groups of the two first air supply passages 27 and the two other air supply passages 38 are connected to the grate block 10 As the diameter of the first air supply passage 27 or the other air supply passage 38 increases continuously as viewed toward the inside of the grate block 10, the combustion residues that have entered the first air supply passage 27 or the other air supply passage 38 can be discharged more easily, thus preventing blockage of the air supply. The diameter of the first air supply passage 27 and the other air supply passage 38 is 15 mm at the end facing the inside of the grate block 10 and 10 mm at the other end.

[0064] During operation, the grate blocks 10 are moved relative to one another by the block holder tubes. Depending on whether the block holder tube is associated with a stationary or a movable grate block, the grate blocks are either fixed to a stationary console or arranged on a console arranged in a movable grate carriage. The drive is provided by hydraulic cylinders, whose rollers move the grate carriage forward and backward over the corresponding running surface.

[0065] The resulting relative motion causes the feet 34 of the first grate block 10 to move forward and backward respectively over the support surface 16 of the succeeding grate block 10. The combustion material is conveyed over the support surface 16 before it is dropped via the edges 19 onto the support surface 16 of the succeeding grate block 10. The present invention has the following aspects (configurations). [Aspect 1] A grate block (10) for a combustion grate, comprising: Successive grate blocks are arranged one on top of the other in a stepped manner and are formed to reconfigure and transport the burning product by thrust movements performed relative to one another, the grate blocks (10) having a block body (12) with an upper wall (14) and defining a longitudinal axis L, the upper wall (14) forming a support surface (16) along which the burning product is transported, the frontmost end of the support surface forming an edge (19) as seen in a thrust direction S oriented approximately parallel to the longitudinal axis L, and the support surface ( a grate block (10) having a first air supply opening (25) formed for supplying air onto said combustion grate by means of a first air supply passage (27) which extends perpendicularly or obliquely to said thrust surface (22) when viewed in longitudinal section, and a lower support edge (23) arranged in a plane E extending approximately perpendicularly to said longitudinal axis L, said lower support edge (23) being determined to be in contact with said support surface of an adjacent grate block in the thrust direction S, The grate block (10) is further characterized in that another air supply passage (38) for cooling the upper wall portion (14) and the front wall portion (20) extends through the upper wall portion (14) and through the front wall portion (20) and is aligned obliquely with respect to the direction of the first air supply passage. [Aspect 2] The grate block (10) according to aspect 1, characterized in that the upper wall portion (14) and the front wall portion (20) are thickened and formed as a wall thickening portion (40) when viewed in longitudinal section in the area where they abut against each other, and the edge portion (19) is located forward with respect to the plane E when viewed in the thrust direction S. [Aspect 3] 3. The grate block (10) according to claim 2, wherein the other air supply passage (38) is disposed within the thickened wall portion (40). [Aspect 4] The grate block (10) according to any one of aspects 1 to 3, wherein the other air supply passages (38) extend at an angle β to the longitudinal axis L of the block body in a vertical cross section, the angle β being between 10° and 60°, preferably between 15° and 50°. [Aspect 5] 5. The grate block (10) according to any one of aspects 1 to 4, characterized in that a first group of the other air supply passages (38) are formed in a first plane extending at a first angle β1 with respect to the support surface of the block body and a second group of the other air supply passages (38) are formed in a second plane extending at a second angle β2 with respect to the support surface of the block body, the first angle β1 being between 10° and 35°, preferably between 10° and 20°, and the second angle β2 being between 35° and 60°, preferably between 40° and 50°. [Aspect 6] The grate block (10) according to aspect 5, characterized in that the first group of other air supply passages (38) are formed parallel to one another, advantageously parallel to a longitudinal plane P perpendicular to the support surface (16), and the second group of other air supply passages (38) are formed parallel to one another, advantageously parallel to the longitudinal plane P. [Aspect 7] The grate block (10) of any one of claims 5 to 6, wherein the other air supply passages (38) are at least approximately uniformly spaced apart from one another in the first plane and / or in the second plane across the entire width of the grate block. [Aspect 8] The grate block (10) according to any one of aspects 1 to 7, characterized in that the other air supply passages (38) are arranged symmetrically with respect to a longitudinal symmetry plane of the grate block (10) extending perpendicular to the support surface (16). [Aspect 9] 9. The grate block (10) according to any one of the preceding aspects, wherein the other air supply passage (38) has a constant cross-sectional area over substantially the entire length of the other air supply passage (38), the cross-sectional area being between 40 mm2 and 100 mm2, preferably 80 mm2. [Aspect 10] The grate block (10) according to any one of aspects 1 to 8, characterized in that the other air supply passage (38) is formed so as to expand continuously from the combustion product side to the cooling air side over the entire length of the other air supply passage (38), and the ratio of the cross-sectional area of ​​the other air supply passage (38) on the combustion product side to the cross-sectional area of ​​the other air supply passage on the cooling air side is 1:1.2 to 1:2.5, advantageously 1:2.25. [Aspect 11] A combustion grate having at least one grate block (10) according to any one of the first to tenth embodiments. [Aspect 12] 12. Use of a combustion grate according to embodiment 11 for the incineration of waste. [Aspect 13] A waste incineration plant having a combustion grate according to embodiment 11. [Explanation of symbols]

[0066] 10. Grate Block 12 Block body 14 Upper wall 16 Support surface 16a,16b Support surface area 17 Transition 19 Edge 20 Front wall 22 Thrust surface 23 Lower support edge 24 Rear wall 25 First air supply port 26 Hook 27 First air supply passage 28a, 28b side wall part 29 Central Web 34 Blocks 35 Other air supply ports 38 Other air supply passages 40 Thick wall section L Longitudinal axis S Thrust direction E plane P longitudinal section d. the distance at which the air supply openings are offset rearward relative to the edge along the longitudinal axis L and in the thrust direction S D the distance at which the edge is offset forward relative to the plane E along the longitudinal axis L and in the thrust direction S α angle β1,β2 angle

Claims

1. A grate block (10) for a combustion grate, comprising: Successive grate blocks are arranged one on top of the other in a stepped manner and are formed to transport the combustion product by a thrust movement performed relative to one another, the grate blocks (10) having a block body (12) with an upper wall (14) and defining a longitudinal axis L, the upper wall (14) forming a support surface (16) along which the combustion product is transported, the frontmost end of the support surface forming an edge (19) as seen in a thrust direction S oriented approximately parallel to the longitudinal axis L, and through which the combustion product is transported to the support surface (16). ) descending towards a thrust surface (22) formed by a front wall (20) having first air supply openings (25) formed for supplying air onto the combustion grate by first air supply passages (27) each extending perpendicularly or obliquely to the thrust surface (22) as viewed in a longitudinal section, and a lower support edge (23) arranged in a plane E extending approximately perpendicularly to the longitudinal axis L, the lower support edge (23) being determined to be in contact with the support surface of an adjacent grate block in the thrust direction S, Another air supply passage (38) for cooling the upper wall portion (14) extends through the upper wall portion (14) and is aligned obliquely with respect to the direction of the first air supply passage; the upper wall portion (14) and the front wall portion (20) are thickened in the region where they abut against each other as a wall thickening portion (40) when viewed in longitudinal section, and the edge portion (19) is disposed forward with respect to the plane E when viewed in the thrust direction S; A grate block (10).

2. 2. The grate block (10) according to claim 1, characterized in that the other air supply passages (38) are arranged in the wall thickening (40).

3. 3. A grate block (10) according to claim 1 or 2, characterized in that the other air supply passages (38), in longitudinal section, extend at an angle β to the longitudinal axis L of the block body, said angle β being between 10° and 60°, preferably between 15° and 50°.

4. 4. The grate block (10) according to claim 1, wherein a first group of the other air supply passages (38) is formed in a first plane extending at a first angle β1 with respect to the support surface of the block body and a second group of the other air supply passages (38) is formed in a second plane extending at a second angle β2 with respect to the support surface of the block body, the first angle β1 being between 10° and 35°, preferably between 10° and 20°, and the second angle β2 being between 35° and 60°, preferably between 40° and 50°.

5. 5. The grate block (10) according to claim 4, characterized in that the other air supply passages (38) of the first group are formed parallel to one another, preferably parallel to a longitudinal plane P perpendicular to the support surface (16), and the other air supply passages (38) of the second group are formed parallel to one another, preferably parallel to the longitudinal plane P.

6. 6. A grate block (10) according to claim 4 or 5, characterized in that the other air supply passages (38) are at least approximately uniformly spaced apart from one another in the first plane and / or in the second plane over the entire width of the grate block.

7. The grate block (10) according to any one of claims 1 to 6, characterized in that the other air supply passages (38) are arranged symmetrically with respect to a longitudinal symmetry plane of the grate block (10) extending perpendicular to the support surface (16).

8. The grate block (10) according to any one of claims 1 to 7, characterized in that the other air supply passage (38) has a constant cross-sectional area over substantially the entire length of the other air supply passage (38), the cross-sectional area being between 40 mm2 and 100 mm2, advantageously 80 mm2.

9. The grate block (10) according to any one of claims 1 to 7, characterized in that the other air supply passage (38) is formed so as to expand continuously from the combustion product side to the cooling air side over the entire length of the other air supply passage (38), and the ratio of the cross-sectional area of ​​the other air supply passage (38) on the combustion product side to the cross-sectional area of ​​the other air supply passage on the cooling air side is 1:1.2 to 1:2.5, advantageously 1:2.

25.

10. A combustion grate comprising at least one grate block (10) according to any one of the preceding claims.

11. Use of a combustion grate according to claim 10 for the incineration of waste.

12. A waste incineration plant comprising a combustion grate according to claim 10.

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