Water-cooled grate block for a combustion plant

Abstract

A cooled grate block (1) as part of a grate for a plant for the thermal treatment of waste, comprising: a block body (3) designed as a casting with an outer support surface (7) for the waste to be treated, a planar cavity (50) arranged directly below the support surface (7) for receiving a cooling fluid, a fluid supply line (52) and a fluid discharge line (54) which are connected to the cavity (50), at least one deflection element (66) arranged in the cavity (50) to direct a cooling fluid in the cavity (50) from the fluid supply line (52) to the fluid discharge line (54), and a distribution element (74) arranged in the end face (11) of the cavity (50) for distributing the cooling fluid fed into the cavity (50) through the fluid supply line (52), characterized in that the planar cavity (50) has a surface extending from the bottom (51) to upper wall (5) has a partition wall (60) extending to the upper wall,which extends from the front wall (15) towards the rear wall (68) of the cavity (50), forms a passage (64) in the area of ​​the rear wall (68) and divides the cavity (50) into two fluid-conducting compartments (62).

Description

[0001] Combustion grates for the large-scale incineration of waste have long been known to those skilled in the art. Such combustion grates can be in the form of pusher grates, which include moving parts to perform stoking strokes. The material to be combusted is conveyed in the direction of transport from an inlet end of the combustion grate to an outlet end and is incinerated during this process. To supply the combustion grate with the oxygen required for combustion, corresponding air inlets are provided through the grate, through which the air – also called primary air – is introduced.

[0002] A commonly used type of combustion grate is the so-called stepped grate. This consists of grate blocks arranged side by side, each forming a row of grate blocks. The rows of grate blocks are arranged one above the other in a step-like fashion, whereby in so-called feed grates, the front end of a grate block (viewed in the direction of feed) rests on a support surface of the adjacent (underlying) grate block (viewed in the direction of transport) and is moved along this support surface during the corresponding feed motion.

[0003] The material being conveyed over the grate blocks generally subjects them to relatively high wear. At the front of each grate block, the material is thrown from the support surface over a corresponding discharge edge (also called a nose) onto the support surface of the following or adjacent grate block below. The mechanical abrasion caused by the material is particularly high in this front end area of ​​the support surface.

[0004] Due to the high temperatures during combustion and in the combustion chamber, the grate blocks are subjected to very high thermal stress. During normal operation of the combustion grate, this thermal stress is particularly high in the area of ​​the contact surface, even though the material being combusted on the grate block provides some insulation. Temperature spikes and the associated stress spikes occur especially when the material being combusted is unevenly distributed on the grate, resulting in only a thin insulating layer in some areas, or when this insulating layer is completely absent. This thermal stress promotes erosion through abrasion and chemical reactions occurring on the contact surface, which further damage it. Ultimately, all of this leads to a reduction in the service life of the grate block.

[0005] To reduce thermal stress, the grate bars are normally cooled from below, i.e., on the side of the combustion grate opposite the combustion process, using a coolant or cooling fluid. Water or air is typically used as the coolant, which is why grate blocks are often referred to as air-cooled or water-cooled. The method of cooling and coolant supply is the subject of numerous patent applications and patents: EP 1 760 400 B1 discloses a water-cooled grate element made of cast steel with deflectors that form meandering water channels. The disadvantage of such a water flow system is that the cooling performance is impaired directly above the deflectors, as the coolant has no contact with the upper wall there and therefore cannot dissipate the heat generated by combustion. Consequently, a combustion surface with so-called "heat hotspots" develops in these areas.

[0006] DE 10 2015 101 356 and EP 1 315 936A1 B1 disclose a grate bar with a cooling coil which extends parallel to the combustion surface and to the front wall.

[0007] EP 0 811 803 B1 discloses cooled grate blocks in which the cooling lines run perpendicular to the feed direction and are deflected outside the grate blocks by means of supports.

[0008] Cooling using the known cooling channels or cooling lines does not cover nearly the entire area of ​​the combustion surface, which promotes the formation of the aforementioned "heat hotspots".

[0009] To achieve the highest possible cooling capacity, maximizing the surface area available for heat exchange is paramount. For liquid coolants, a consistent flow of the coolant is also crucial. Otherwise, turbulence and bubble formation can occur in the cooling lines, reducing the cooling capacity of the grate blocks.

[0010] The object of the invention is therefore to eliminate the disadvantages of the prior art and to provide a grate block in which the cooled area is proportionally maximized and at the same time the occurrence of turbulence in the coolant flow is reduced, so that the cooling performance can be further improved.

[0011] This problem is solved according to the invention with a grate block according to claim 1 and a grate according to claim 16. Preferred embodiments of the invention are described in the dependent claims.

[0012] The invention relates to a cooled grate block as part of a grate for a plant for the thermal treatment of waste. In this grate, the grate blocks are typically arranged one above the other in a stepped fashion and are designed such that they rearrange and convey the material to be combusted during combustion by means of relative shear movements. The grate block according to the invention comprises a block body formed as a casting with an upper wall. The upper wall forms an outer support surface for the waste to be treated, which runs at least partially parallel to a longitudinal axis L of the block body. Furthermore, the grate block according to the invention comprises a planar cavity arranged directly below the support surface for receiving a cooling fluid.The planar cavity is bounded on the top by the upper wall, at the front by a front wall, on the bottom by a base, at the rear by a back wall, and laterally by side walls, the base being at least partially formed by a base plate. The grate block according to the invention further comprises a fluid supply line and a fluid outlet line, both of which are connected to the cavity, as well as at least one deflection element arranged in the cavity to direct the cooling fluid from the fluid supply line to the fluid outlet line. A distribution element for distributing the cooling fluid fed into the cavity via the fluid supply line is also located in an end-face region of the cavity of the grate block according to the invention.

[0013] Preferably, the at least one deflection element is located in the cavity in a rear area of ​​the back wall.

[0014] For the purposes of the present invention, grate blocks arranged one above the other in a stair-like manner are defined as grate blocks on a grate, which are arranged like the steps of an ascending or descending staircase.

[0015] The term "relatively executable shear movements" refers to shear movements that can be performed parallel to the longitudinal axis of the grate, which consists of grate blocks. In the case of a stepped grate, the direction of movement is therefore parallel to the incline or slope of the grate.

[0016] The "longitudinal axis of the grate block" refers to an axis that extends parallel to the axis of the stepped grate – i.e., from the front wall to the rear wall of the grate block – and thus runs parallel to the direction of movement of the waste being processed. If the grate block is oriented so that the longitudinal axis and a transverse axis perpendicular to it are arranged in the horizontal plane, then the front wall is preferably arranged at least approximately in the vertical plane.

[0017] For the purposes of this application, a "support surface" is understood to be a surface located on the outer top side, i.e., on the opposite side of the cavity, on which the waste (fuel material) intended for thermal treatment rests. As mentioned at the outset, this support surface is known to be exposed to increased thermal stress in incineration plants and is susceptible to erosion and the build-up of combustion products.

[0018] For the purposes of this application, a fluid flow or cooling fluid flow is defined as a flow of cooling fluid - preferably water - which is directed through the cavity from the fluid supply line to the fluid discharge line or vice versa.

[0019] For the purposes of the present invention, the term "planar cavity" means that the cavity has a shape whose horizontal dimensions (length and width) are greater than its vertical dimensions (height). Preferably, the cavity has a cuboid shape, at least partially, with the largest area parallel to the support surface. In particular, no pipes are provided in the planar cavity to transport the fluid from the fluid supply line to the fluid discharge line.

[0020] In the following, fluid supply lines and fluid discharge lines are defined as lines suitable for directing cooling fluid into and out of the cavity. It should be explicitly noted that the fluid flow can occur in both directions, meaning it can be alternately supplied and discharged through both lines.

[0021] For the purposes of the present invention, the term "front side" or "front face" means the side in the area of ​​the front wall.

[0022] For the purposes of the present invention, a distribution element is defined as an obstruction designed to restrict and / or change the direction of the flow, thereby distributing the incoming cooling fluid. The distribution of the cooling fluid preferably occurs before or in the region where the cooling fluid enters the planar cavity. The distribution element can have various shapes, as will be explained in more detail below.

[0023] The grate block according to the invention has the advantage over the prior art that the cooling fluid flow entering the cavity can be distributed evenly across the width of the cavity thanks to the distribution element. This reduces or even completely prevents the formation of cooling fluid turbulence and foaming, resulting in increased cooling capacity of the grate block. The increased cooling capacity reduces the thermal stress and wear on the grate blocks and also results in less combustion residue being baked onto the grate blocks, thus requiring less frequent cleaning and maintenance. Ultimately, this leads to less maintenance work and therefore more economical operation of the combustion plant.

[0024] As described above, the flat cavity usually does not contain any pipes that could impair the even distribution of the cooling fluid in the cavity and thus reduce the cooling performance.

[0025] Preferably, the distribution element extends at least partially along a lateral axis that runs at least approximately parallel to the front wall. This enables a regular distribution of the cooling fluid across the width of the planar cavity (or a compartment of the planar cavity).

[0026] In a preferred embodiment of the grate block, the planar cavity is connected to an end-face chamber. This chamber preferably extends substantially parallel to—and preferably over at least half the length of—the front wall. It is preferably designed such that the cooling fluid flows into and out of the planar cavity through the chamber. Such an embodiment is shown in the attached [reference]. Figur 2 depicted.

[0027] The planar cavity and the chamber are preferably connected to each other via several inlet openings. This preferably allows for a pre-distribution of the cooling fluid before it reaches the distribution element and thus also contributes to a better distribution of the cooling fluid in the planar cavity.

[0028] The injection of cooling fluid through the chamber into the cavity also allows the front wall, often referred to as the nose, to be cooled as well. Although the front wall is usually exposed to a slightly lower thermal load than the contact surface, its cooling helps to prevent the build-up of fly ash or other combustion products.

[0029] In a preferred embodiment of the grate block, the planar cavity has a partition extending from the bottom to the upper wall. This partition preferably extends from the front wall towards the rear wall of the cavity and preferably forms a passage in the region of the rear wall, so that the cavity is divided into two fluid-conducting compartments.

[0030] Due to the partition, the fluid flow is preferentially directed through a first compartment of the cavity, which extends from the front wall along the longitudinal axis over a desired length of the cavity. At the rear wall, the fluid flow is guided through the passage, where it is redirected and flows back in the opposite direction, i.e., towards the front wall, through a second compartment adjacent to the first. Thanks to the partition, the rear areas of the cavity are also adequately supplied with fresh cooling fluid, thus ensuring cooling performance in these areas as well.

[0031] It has been observed that in known water-cooled grate blocks, air is carried into the cavity by the cooling fluid flow and can become trapped there as air inclusions, particularly in corners or hard-to-reach areas. Due to the lower density of air compared to water, any air inclusions tend to accumulate on the upper surface of the cooling chamber. Since the thermal conductivity of air is significantly lower than that of water, such air inclusions reduce the cooling capacity of the grate block. Therefore, in the case of a liquid cooling fluid, the grate block according to the invention preferably includes at least one vent opening for venting the cavity or compartments to expel any such air inclusions from the grate block. Simultaneously, venting the cavity or compartments prevents air from being carried along with the cooling fluid over the entire length of the fluid flow.

[0032] If the cavity is divided into compartments by a partition wall, the vent opening is preferably formed in the partition wall, preferably in the area of ​​the front wall, in order to allow ventilation of the cavity or the compartments created by the partition wall.

[0033] Preferably, the vent opening has a diameter of 2–12 mm, particularly preferably 4–5 mm. This size allows the grate block, including the vent opening, to be produced using known casting methods.

[0034] In a preferred embodiment of the grate block, the partition wall runs at least approximately parallel to one of the side walls and is preferably arranged centrally within the cavity. In this embodiment, the partition wall thus divides the planar cavity into two compartments of at least approximately equal size. This ensures that the fluid flow is uniform through the cavity or through the compartments and is not accelerated or decelerated due to a change in the cavity or compartment geometry. This prevents turbulence from forming due to an acceleration or deceleration of the fluid flow within the cavity or the compartments.

[0035] Preferably, the fluid supply line and the fluid drain line are connected to the flat cavity in the area of ​​the front wall. Connecting the fluid supply line and the fluid drain line to the cavity in the front or end face area frees up as much space as possible below the block body.

[0036] Preferably, both the fluid supply line and the fluid outlet line have an inner diameter of 20–32 mm, more preferably 22–30 mm, and most preferably 26–28 mm. Line diameters of this size have the advantage that, for the usual cooling fluid circulation rate, a flow velocity is achieved at which the flow automatically vents the entire piping system of the grate block, including the cavity. Depending on the embodiment, the distribution element can extend over the entire width of the cavity or only over parts of it.

[0037] In a preferred embodiment of the grate block, the distribution element is designed to allow only a restricted flow of cooling fluid past or over the distribution element, in order to enable uniform distribution of the cooling fluid within the cavity. This uniform distribution of the cooling fluid flow enables increased cooling performance, as turbulence of the cooling fluid and foaming are reduced or prevented.

[0038] In a particular preferred embodiment, the cooling fluid flowing in through the fluid supply line first encounters the distribution element, thereby calming turbulence. The water can preferably flow through openings in the distribution element (if present), over or around it.

[0039] In a preferred embodiment of the grate block, the distribution element is designed in the form of a baffle plate or a deflector plate. Further preferred embodiments include a distribution element designed as a boss, baffle, perforated plate, or crossbeam. The longitudinal axis of the distribution element preferably runs approximately parallel to the front wall.

[0040] If the distribution element is shaped like a hump, this means that the distribution element has a hill- or ramp-shaped cross-section in the width direction, i.e., parallel to the front wall. The cooling fluid thus flows perpendicular to the front wall and in the opposite direction to the movement of the material being combusted over the distribution element.

[0041] In the case of a perforated plate, it is understood here that the distribution element consists of a plate which has a front surface facing the fluid flow with at least one opening through which the fluid flow is directed.

[0042] In the case of a crossbeam, it is understood here that the distribution element forms a wall or a beam over or under which the cooling fluid can flow. Preferably, the beam extends along the entire width of the grate block and at least approximately parallel to the front wall.

[0043] As mentioned above, the distribution element ensures a uniform distribution of the cooling fluid flow across as much of the cavity's width as possible, and, if the cavity has compartments, across the width of those compartments. This uniform distribution of the cooling fluid flow allows for increased cooling performance, as turbulence of the cooling fluid and foaming can be reduced or prevented. The distribution typically occurs at the point where the cooling fluid enters the cavity and can be achieved using a simple distribution element. The distribution element can preferably be cast in place or subsequently installed as a separate component.

[0044] Furthermore, the distribution element preferably extends in the width direction at least over the width of an opening cross-section of the fluid supply line.

[0045] In a preferred embodiment of the grate block, the distribution element is connected to the base and / or to the upper wall. If the distribution element is designed as a crossbeam, it preferably forms a slot-like fluid passage opening with the upper wall and / or the base. The fluid passage opening is particularly preferably located between an upper edge of the crossbeam and the upper wall. The fluid passage opening preferably has a clear width of 1 to 15 mm, more preferably 2 to 10 mm, and more preferably 3 to 6 mm.

[0046] With regard to a uniform distribution of the cooling fluid flow entering the cavity, the above-described embodiment of the distribution element as a crossbeam with the above-mentioned properties has proven to be particularly effective.

[0047] In another preferred embodiment of the grate block, the distribution element is located in the outlet region of the at least one inlet pipe. It has been observed that turbulence in the cooling fluid occurs particularly frequently at the point of entry into the cavity – i.e., at the outlet of the inlet pipe. Since the thermal stress is particularly high in the front region of the grate block, a reduction in cooling performance due to air inclusions has a doubly negative effect there. By arranging the distribution element in the outlet region of the inlet pipe, rapid stabilization is achieved upon entry of the cooling fluid into the cavity.

[0048] Preferably, the distribution element comprises a bump-, ramp-, or hill-like obstacle that restricts or deflects the flow of the cooling fluid from the fluid supply line. The distribution element preferably has a height of 5–15 mm, particularly preferably 8–12 mm, and most preferably 10 mm, and a width of preferably 20–40 mm, particularly preferably 25–35 mm, and most preferably 30 mm.

[0049] The combination of a hump-shaped or rampart- or hill-like distribution element, located at the outlet of the inlet pipe, has proven highly effective in distributing the cooling fluid flow within the cavity. Furthermore, such a distribution element can be easily manufactured using known casting methods and is therefore preferred.

[0050] In the event that the distribution element is designed as a crossbeam, the distribution element preferably has an area which is at least 50% of the vertical cross-sectional area of ​​the cavity or the respective compartment.

[0051] The crossbeam preferably has a thickness of 2 mm to 10 mm and a length of 50 mm to 250 mm.

[0052] In the event that the distribution element is designed as a crossbeam, it preferably extends over at least 50%, preferably over at least 75% and particularly preferably over at least 90% of the width of the cavity or the respective compartment.

[0053] In a preferred embodiment of the grate block, the upper wall and / or the front wall has at least one air supply opening. This air supply opening allows additional air to be introduced into the combustion chamber to ensure optimal combustion. Starting from the upper wall, the air supply opening can widen concentrically downwards (volcano-shaped), thus preventing the air supply opening from becoming clogged with thermally treated waste. Such volcano-shaped air supply openings are preferably arranged in the upper wall. Furthermore, they preferably have an oval opening cross-section with a diameter of 33–45 mm and a narrowing of 4–12 mm. They also preferably widen towards the bottom plate at an angle of 18–22° to a smaller diameter of 22–28 mm.

[0054] The block body is preferably manufactured as a single casting and preferably also includes a portion of the base. The base plate, which preferably forms at least part of the base, is preferably welded to the block body and thus defines the cavity. This means that preferably a portion of the base is formed as an integral part of the block body, and the cavity is furthermore defined at least partially on the base side by the base plate. This allows for simple fabrication of the cavity, since the casting can be produced in one step and the cavity can then be formed by attaching, preferably by welding, the base plate. Such a method of manufacturing the block body is particularly advantageous and makes the block body especially durable and low-maintenance.The expert is of course aware that the casting can be further processed before the base plate is attached, for example by using an abrasive.

[0055] In a preferred embodiment of the grate block, the cavity extends over at least 2 / 3 of the length of the bearing surface. Furthermore, the cavity preferably extends over at least 3 / 4 of the width of the bearing surface. This ensures that the largest possible surface area is available for heat exchange.

[0056] The cavity should preferably cover at least the contact surface for the waste to be treated, so that no thermally stressed, uncooled area of ​​the block body is created.

[0057] Preferably, the cooling fluid maintains a temperature of 20–140 °C during the operation of the grate block, i.e., during the combustion of high-calorific waste such as household or commercial waste, thereby achieving operating temperatures for the grate block of up to 250 °C. Furthermore, water—preferably—is used as the cooling fluid in a closed circuit to prevent oxygen ingress and thus the formation of corrosion. When water is used as the cooling fluid, it preferably contains no or only a small amount of limescale.

[0058] The invention further relates to a grate comprising several of the grate blocks described above.

[0059] The invention will now be explained in more detail with reference to some exemplary embodiments illustrated in the figures. Where alternative embodiments differ only in individual features, the same reference numerals have been used for the features that remain the same. The figures are shown purely schematically: Fig. 1 a perspective view of an embodiment of a grate block according to the invention; Fig. 2 a perspective view of an embodiment of a planar cavity; Fig. 3 a perspective view of an embodiment of the grate block made of Fig. 1 with the flat cavity made of Fig. 2 ; Fig. 4a a longitudinal section along the longitudinal axis L through an embodiment of a front region of the block body made of Fig. 1 ; Fig. 4 longitudinal section along the longitudinal axis L through an embodiment of a front region of the block body made of Fig. 1 ; Fig. 5 a cross-section along width axis Q through an embodiment of a front region of the block body made of Fig. 1 ; and Fig. 6 a longitudinal section along the longitudinal axis L through an embodiment of the block body made of Fig. 1 .

[0060] The in Fig. 1 The grate block 1 according to the invention, as illustrated, serves for the thermal treatment of waste as incineration material (not shown), which is moved or conveyed over the grate in a direction of movement B. The grate block 1 comprises a block body 3 with an upper wall 5 and side walls 6. The upper wall 5 comprises an outer bearing surface 7, which extends along a longitudinal axis L of the grate block 1 from a rear region 9 of the block body 3 towards a front region 11 of the block body 3. Furthermore, the block body 3 comprises a rounded overhang 13 in the front region 11 (hereinafter referred to as the nose), which connects the front region 11 with a front wall 15.

[0061] In a grate arrangement (not shown) in which several individual grate blocks 1 are arranged one above the other in a stepped fashion, a sliding surface 17 adjacent to the front wall 15 rests on the support surface 7 of another grate block (not shown). Thermally treated waste is conveyed in the direction of movement B by means of relative shear movements. For this purpose, the sliding surfaces 17 slide on the support surfaces 7 of the grate blocks arranged below (not shown). The relative shear movements are executed along the longitudinal axis L and are driven by a drive device (not shown), which transmits the movement to the block body via a support 19. In such a grate arrangement, several grate blocks can be positioned next to each other, so that the side walls 6 of grate block 1 abut the side walls of other grate blocks.

[0062] The block body 3 includes air supply openings 21, 23, which are arranged in the front wall 15 and the upper wall 5 and through which the thermally treated waste can be supplied with air to promote combustion. Embodiments without air supply openings are also conceivable, but are not shown here. The air supply openings 23 in the upper wall 5 are preferably designed as downwardly widening passages, so that parts of the waste to be treated do not become trapped in the opening if they pass through.

[0063] The block body 3 also includes a planar cavity 50. As in Fig. 2 As shown, the planar cavity 50 opposite the upper wall 5 of the block body 3 is bounded by a base 51 and a base plate 53. The cavity 50 further includes a fluid supply line 52 and a fluid discharge line 54, each of which is connected to a chamber 56. The chamber 56 extends essentially parallel to the front wall 15 ( Fig. 1 ) and is connected to the planar cavity 50 via inlet openings 58. The planar cavity 50 further comprises a partition wall 60, which extends from the front wall (reference numeral 15 in Fig. 1 ) towards a rear wall 68 ( Fig. 3 ) extends and forms a passage 64, so that the cavity 50 is divided into two compartments 62.

[0064] Fig. 3 shows a view from below of a section through grate block 1. Fig. 1 in connection with the Fig. 2 described flat cavity 50. The base plate 53 made of Fig. 2 The boundary of the cavity 50 has been removed here. The planar cavity 50 comprises deflection elements 66, which direct the fluid flow from the fluid supply line 52 ( Fig. 2 ) to fluid drainage line 54 ( Fig. 2 redirect. In Fig. 3 It is also clearly visible how the planar cavity 50 in the rear area 9 of the block body 3 is bounded by the side walls 6 and the rear wall 68. Furthermore, in Fig. 3 It is clearly visible that the air supply openings 23 pass from the upper wall through the flat cavity 50.

[0065] Fig. 4a and 4b show a longitudinal section along the longitudinal axis L through the front area of ​​the block body. Fig. 1 with the air supply openings 21 in the front wall 15. It is further evident that the partition 60, which divides the cavity 50, has an opening 70 that serves to vent the compartments 62 created by the partition 60. The inlet opening 58 includes a distribution element 74 in an outlet area 72 facing the cavity 50, which here is designed as a hump- or hill-like obstacle. The fluid flow, which is directed into the cavity 50 via the inlet opening 58, is distributed by means of the distribution element 74 so that no turbulence forms within the planar cavity 50, which would lead to foaming or air bubbles and thus to reduced cooling performance. The bottom 51 limits the cavity 50 at the bottom. The bottom plate 53 is not shown. Fig. 2 , which would connect to the ground in the longitudinal direction L. The distribution element 74 could also be designed as a crossbeam instead of the hump- or hill-like obstacle (not shown).

[0066] Figur 5 shows a cross-section through the front wall 15 with the in Fig. 2 The chambers 56 shown contain the fluid supply line 52 and the fluid outlet line 54, respectively. The cooling fluid flows into chamber 56 through the fluid supply line 52 and distributes itself through the inlet openings 58 in the cavity (not shown). After passing through the cavity, the cooling fluid flows through the inlet openings 58' into chamber 56' and exits the block body 3 through the fluid outlet line 54. The fluid outlet line 54 may be connected to another fluid supply line of a further block body (not shown).

[0067] The illustrated ingots have a longitudinal length L of 400–800 mm, preferably 500–750 mm, and particularly preferably 650–700 mm. The illustrated ingots have a width Q of 280–500 mm, preferably 320–460 mm, and particularly preferably 380–420 mm. The illustrated ingots have a height of 100–200 mm, preferably 130–180 mm, and particularly preferably 150–160 mm. The ingot is preferably made of low-alloy to high-alloy cast steel. Compared to unalloyed cast steel, low-alloy to high-alloy cast steel additionally contains varying proportions of alloying elements such as chromium, nickel, molybdenum, vanadium, tungsten, and others. The ingot is preferably manufactured by casting or injection molding. The inlet openings preferably have a diameter of 12 - 28 mm and particularly preferably a diameter of 16 - 22 mm.

[0068] Figur 6 shows a longitudinal section along the longitudinal axis L through the block body 3 made of Fig. 1 The distribution element in a front area 76 of the cavity 50 is not shown. The base 51 is formed as an integral part of the block body 3 and, together with the base plate 53, delimits the cavity 50 at the bottom. Furthermore, the cavity 50 is delimited by the rear wall 68 and the front wall 15. The base plate 53 has air supply openings 21, analogous to the upper wall 5. The air supply openings 21 extend concentrically from the upper wall 5 towards the base plate 53.

Claims

1. A cooled grate block (1) as part of a grate for a plant for the thermal treatment of waste, in which the grate blocks are arranged one above the other in a stepped manner and are designed to rearrange and convey the fuel during combustion by means of pushing movements carried out relative to one another, comprising a block body (3) designed as a cast part with an upper wall (5) which forms an outer support surface (7) for the waste to be treated, running at least partially parallel to a longitudinal axis (L) of the block body (1), a flat cavity (50) arranged directly below the support surface (7) for receiving a cooling fluid, which is bounded on the top side by the upper wall (5), on the front side by a front wall (15), on the bottom side by a base (51), on the back side by a rear wall (68), and laterally by side walls (6), wherein the base (51) is formed at least partially by a base plate (53),a fluid supply line (52) and a fluid discharge line (54) which are connected to the cavity (50), at least one deflection element (66) arranged in the cavity (50) to direct a cooling fluid in the cavity (50) from the fluid supply line (52) to the fluid discharge line (54), and a distribution element (74) arranged in a front region (76) of the cavity (50) for distributing the fluid fed into the cavity (50) through the fluid supply line (52), characterized in that the flat cavity (50) has a partition wall (60) extending from the bottom (51) to the upper wall (5), which partition wall extends from the front wall (15) in the direction of the rear wall (68) of the cavity (50), forms a passage (64) in the region of the rear wall (68) and divides the cavity (50) into two fluid-conductingly connected compartments (62).

2. Grate block according to claim 1, characterized in thatthe distribution element (74) extends at least in sections along a width axis (Q) which runs at least approximately parallel to the front wall (15).

3. Grate block according to claim 1, characterized in that the flat cavity (50) is connected to a front-side chamber (56) which extends substantially parallel to the front wall (15) and through which the cooling fluid inflow into the flat cavity (50) or the cooling fluid outflow from the cavity (50) takes place.

4. Grate block according to claim 3, characterized in that the flat cavity (50) and the chamber (56) are connected to one another via several inflow openings (58).

5. Grate block according to claim 1, characterized in that the partition wall (60) has an opening (70) in the region of the front wall for ventilating the cavity (50) or the compartments (62) created by the partition wall (60).

6. Grate block according to one of claims 1 or 5, characterized in thatthe partition wall (60) runs at least approximately parallel to one of the side walls (6).

7. Grate block according to one of claims 1 to 5, characterized in that the fluid supply line (52) and the fluid discharge line (54) are connected to the flat cavity (50) in the region of the front wall (15).

8. Grate block according to one of claims 1 to 7, characterized in that the distribution element (74) is preferably designed in the form of a hump, a panel, a perforated plate or a crossbar which runs at least approximately parallel to the front wall (15).

9. Grate block according to one of claims 4 to 8, characterized in that the distribution element (74) is located in an opening region (72) of at least one of the inflow openings (58).

10. Grate block according to one of claims 1 to 9, characterized in thatthe distribution element (74) comprises a hill-like projection which restricts or deflects the flow of the cooling fluid from the fluid supply line (52).

11. Grate block according to one of claims 1 to 10, characterized in that the distribution element (74) is designed such that it only allows a limited flow of cooling fluid past the distribution element (74) in order to enable a uniform distribution of the cooling fluid within the cavity (50).

12. Grate block according to one of claims 1 to 11, characterized in that the upper wall (5) and / or the front wall (15) has at least one air supply opening (21, 23).

13. Grate block according to one of claims 1 to 12, characterized in that the block body (3) is manufactured in one piece as a cast part and the base plate (53) for delimiting the cavity (50) is preferably welded to the block body (3).

14. Grate block according to one of claims 1 to 13, characterized in thatthe cavity (50) extends over at least 2 / 3 of the length and / or over at least 3 / 4 of the width of the support surface (7).

15. Grate comprising several grate blocks according to one of claims 1 to 14.