EP2184540A1 - Air-cooled grate block - Google Patents

Abstract

The air-cooled grate block (1) has a block body (5) embodied as a cast part, which has an upper wall (10) and a front wall (20). The upper wall forms a bearing surface (15), and a base (25) is pre-formed in the front wall. A cooling channel (40) is connected with another cooling channel (60). Another cooling channel is formed at a wall inlet (35) by one of an inlet opening (50) arranged adjacent to the base. The front wall and a cooling channel wall (55) are spaced from the upper wall. An independent claim is included for a grate with multiple grate block rows.

Description

The present invention relates to a grate block as part of a grate for a plant for thermal treatment of waste.

The heart of a waste incineration plant is the combustion grate. The waste, such as household waste, is transported from one end of the combustion grate to the other end of the combustion grate. The oxygen required for the combustion of the residues is contained in sufficient amount in the air. The air, also called primary air, is thereby pressed from below through the combustion grate and thus fed to the firing chamber with the residues to be incinerated.

One type of the various known types of combustion grate is the so-called stair grate. Such a stair grate comprises juxtaposed and firmly connected grate blocks, which form the individual grate block rows. The successive grate block rows are staggered to each other and lie with their combustion chamber facing the front walls of the grate blocks, which form the grate block rows on each other. Some of the rows of grate blocks, for example every other, are movably arranged. By the lifting movement of this movably arranged grate block rows of the residue is transported to the following in the transport direction grate block row.

The residues burned in an incinerator mentioned above are very different. The spectrum ranges from household waste to commercial waste right through to the actual Fuels, such as wood in the form of sawdust, biomass and the like. The calorific value of these residues is, depending on the nature of the residue, naturally very different. However, there are also large fluctuations in the calorific value within a type of residue. These strong fluctuations in the calorific value also result in strong fluctuations in the thermal and mechanical loading of the combustion grate or of the individual grate blocks.

At average calorific values (up to about 10 MJ / kg), the combustion grates or the individual grate blocks can be sufficiently cooled with air (primary air). For residues with a higher calorific value, combustion grates with water-cooled grate blocks are known from the prior art. Sufficient cooling of the grate blocks is very important, otherwise there is a risk of melting the combustion grate.

EP 1 191 282 describes a grate block, which has a cooling space for water on its side facing away from the firebox.

EP 1 219 898 discloses a grate block with a cooling element mounted below the support surface for the waste. Again, water is used for cooling.

DE 10 2004 032 291 discloses an air-cooled grate plate with below the top of the grate plate is formed a flow channel.

Although with water cooled grate blocks a means is available that allows the production of efficiently cooled combustion grates, such combustion grates have the disadvantage that both their Production and the subsequent process engineering effort is much higher than in combustion grates, which are composed of air-cooled grate blocks.

Object of the present invention is to provide a grate block available that has at least as good wear resistance and thus an equal long life compared to water-cooled grate block and at the same time avoids its disadvantages of high production and process engineering effort.

The object is achieved by a grate block with the features of the independent claim 1. Preferred embodiments are subject of the dependent claims.

The inventive grate block has the features according to claim 1. The grate block has a block body, which is designed as a cast part. The block body has an upper wall forming a support surface and a front wall to which a foot is formed. The grate block is part of a grate for the thermal treatment of waste. The grate blocks are arranged one above the other like a staircase and the individual grate blocks lie with the formed on the front wall foot on the support surface formed by the upper wall of the subsequent grate block (staircase). The waste to be treated thermally also rests on this bearing surface formed by the upper wall. The rust may have a tendency. This inclination is in a range of 0 ° to 26 °, preferably in the range of 10 ° to 18 ° relative to an imaginary horizontal plane. On a bottom of the upper wall is a wall inlet arranged. This wall inlet lies on the side of the upper wall facing away from the firebox. Starting from the wall inlet, a first cooling channel section extends through the upper wall and the front wall to an outlet opening arranged in the front wall. Adjacent to the front wall and the foot formed thereon, an inlet opening is arranged. From the inlet opening is a cooling passage wall, which is spaced from the front wall and the upper wall, and forms at the wall inlet with the first cooling passage portion fluidly connected second cooling passage portion.

The first cooling channel section and the second cooling channel section together form a cooling channel, which shows a substantially S-shaped profile in longitudinal section. The cross-section or the cross-sectional area of the first cooling passage section and of the second cooling passage section-and thus of the substantially S-shaped cooling passage-is constant in the simplest embodiment. The cross section can also vary.

The grate block according to the invention allows the use of gaseous cooling media, in particular air, even in the thermal treatment of residues with a higher calorific value (> 10MJ / kg). Water cooling, which is often required for higher calorific value residues, is eliminated. The grate block according to the invention makes possible an excellent and differentiated cooling of those points of the grate block which are thermally exposed to the greatest loads. This is very advantageous because, in the case of cooling with air, the primary air available for cooling is limited. Furthermore, the primary air used for cooling is around 120 ° C heated to 150 ° C, which is why it can be dispensed with (previously required) preheating the primary air. In addition, in addition to eliminating the preheating of the primary air, even cooler primary air can be used for cooling, as was previously possible. This additionally improves the overall cooling. The grate block according to the invention achieves excellent, ie long, service lives which are comparable to the service lives of water-cooled grate blocks.

In a preferred embodiment, the first cooling passage section and the second cooling passage section have a varying cross-section. With cross-section, the cross-sectional area of the first and second cooling channel section is designated. The shape of the cross-sectional area may be different. Possible cross-sectional shapes are rectangular, quadrangular, polygonal, e.g. a flattened hexagon, circular or oval.

The heat removal of the gaseous cooling medium, preferably the primary air, denotes the amount of heat dissipated by the cooling medium per time. The heat dissipation depends inter alia on the flow velocity of the cooling medium relative to its surroundings, in the present case of the first and the second cooling channel section. It is greater, the higher the flow velocity of the cooling medium.

If the cross section of the two cooling channel sections varies, this means that the cross-sectional area changes. The cross-sectional area can be smaller or larger. For example, if the cross-sectional area becomes smaller, the flow velocity of a gaseous cooling medium, preferably the primary air, increases, which results Increased heat removal by the gaseous cooling medium leads to higher cooling. Increased heat removal means that the gaseous cooling medium absorbs a larger amount of heat from its surroundings and, due to the increased flow velocity due to the reduced cross-sectional area, dissipates it. With a corresponding variation of the cross section of the first and the second cooling channel section, a very differentiated cooling of individual regions of the grate block is achieved. The cooling can be tailored to the particular thermal load of the individual grate block area. For example, the front wall of the grate block can be specifically intensified cooled.

By widening the cross section of the first cooling passage section or the second cooling passage section in regions which are less thermally stressed, the flow velocity of the gaseous cooling medium, e.g. the primary air, and thereby also the heat dissipation achieved. This makes it possible to work with a limited amount of cooling medium, e.g. Primary air to cool even less thermally stressed areas of the grate block, whereby the cooling is improved overall.

In another embodiment, the block body has a rib extending in the longitudinal direction of the block body. The rib is formed on the upper wall and the front wall and arranged substantially perpendicular thereto. The rib increases the stability of the grate block.

In a preferred embodiment, the rib is a central rib, ie, it is centered in the transverse direction of the block body. The arrangement of the rib in In addition, the middle simplifies the production of the cast-iron grate blocks according to the invention, since identical half-shells can be used.

In a preferred embodiment, the first cooling passage section and the second cooling passage section connected to the latter extend over the entire length of the upper wall of the grate block according to the invention. This achieves cooling of the grate block over the entire length of the upper wall.

However, according to another embodiment, it is also possible for the first cooling passage section and the second cooling passage section to extend over only a part of the length of the upper wall. The first cooling channel section and the second cooling channel section preferably extend over 10% to 90%, particularly preferably over 30% to 70%, of the length of the upper wall of the grate block.

In a further embodiment of the grate block according to the invention, the cross section of the second cooling passage section increases from the inlet opening to the wall inlet. The cross section of the first cooling passage section, on the other hand, decreases in size from the wall inlet to the outlet opening. The change in cross section can be done both continuously and in discrete stages. A continuous change in cross section results, for example, when the first and / or the second cooling channel section has a conical section. By changing the cross section of the first cooling passage section and the second cooling passage section, zones with different degrees of cooling result in the first cooling passage section and in the second cooling passage section. The cooling is in zones with larger Cross section weaker and stronger in zones with smaller cross section.

In another embodiment, the grate block on the rib, preferably a central rib, integrally formed and substantially perpendicularly projecting from this deflecting webs. These deflecting webs are arranged offset to one another.

In a further embodiment, the deflection webs form a meandering channel, which is flow-connected to the second cooling channel section at the inlet opening. A channel inlet opening in this case has a position that is dependent on a relative position of the grate block to a subsequent in a direction L grate block.

The direction L corresponds to the conveying direction of the waste in the longitudinal direction of the grate. The waste passes through different zones, starting with the drying zone at the end of the grate over the combustion zone up to the burn-out zone at the other end of the grate opposite the drying zone.

In a preferred embodiment, the upper wall of the grate block on its combustion chamber facing the side of trough-shaped depressions.

The trough-shaped depressions are located in an area of the upper wall, which is adjacent to the front wall of the grate block. In this area, waste or slag is constantly on during operation of the grate, which means a strong thermal load.

During operation of the combustion grate, burnt waste or slag collects in these trough-shaped depressions. The burnt waste or slag forms an insulating layer between the top wall and the firebox, thus reducing the heat input from the firebox to the grate block

The grate blocks according to the invention can be used in a grate. Such a grate preferably comprises only grate blocks according to the invention.

A grate usually has a plurality of stationary grate block rows and movable grate block rows. This grate block rows are formed by a plurality of juxtaposed and mounted on a block holder tube grate blocks, wherein the grate blocks arranged side by side are firmly connected. The stationary and movable grate block rows are arranged alternately and in steps. In this case, both the stationary and the movable grate block rows are formed by grate blocks according to the invention.

While the block holder tubes are mounted from fixed grate block rows to stationary consoles, block holder tubes are associated with movable grate carriages of movable grate block rows. These grate carriages are driven for example by means of hydraulic cylinders and thereby moved back and forth about roles. As a result, the movable grate block rows are also moved and thus exert a shear and shear action on the resting on the grate waste. Thus, the waste is on the one hand circulated, which are always exposed to new waste parts of the thermal treatment in the firing space. On the other hand Thus, a steady forward promotion of waste in the direction of a grate end is achieved.

Fig. 1

eine erste Ausführungsform des Rostblocks im Längsschnitt;

Fig. 2

eine weitere Ausführungsform des Rostblocks im Längsschnitt;

Fig. 3

eine weitere Ausführungsform des Rostblocks im Längsschnitt, mit einer verlängerten oberen Wand;

Fig. 4

eine weitere Ausführungsform des Rostblocks im Längsschnitt mit einem im Wesentlichen S-förmigen Kühlkanal mittlerer Länge bezogen auf die von der vorderen und der hinteren Wand begrenzte Strecke;

Fig. 5

eine weitere Ausführungsform des Rostblocks im Längsschnitt mit kurzem im Wesentlichen S-förmigem Kühlkanal;

Fig. 6

eine weitere Ausführungsform des Rostblocks im Längsschnitt mit kurzem im Wesentlichen S-förmigem Kühlkanal und zusätzlichen versetzt angeordneten Umlenkstegen;

Fig. 7

eine Ausführungsform des Rostblocks im Querschnitt;

Fig. 8

eine weitere Ausführungsform des Rostblocks im Querschnitt;

Fig. 9

eine weitere Ausführungsform des Rostblocks im Querschnitt mit einer muldenförmigen Vertiefung auf der dem Feuerungsraum zugewandten Seite der oberen Wand;

Fig. 10

drei nebeneinander angeordnete Rostblöcke gemäss Fig. 7 im Querschnitt;

Fig. 11

drei nebeneinander angeordnete Rostblöcke gemäss Fig, 8 im Querschnitt;

Fig. 12

drei nebeneinander angeordnete Rostblöcke gemäss Fig. 9 im Querschnitt;

Fig. 13a

vier treppenartig übereinander angeordnete Rostblöcke gemäss der in Fig. 6 gezeigten Ausführungsform, wobei die beweglich angeordneten Rostblöcke maximal ausgefahren sind;

Fig. 13b

vier treppenartig übereinander angeordneten Rostblöcke gemäss der in Fig. 6 gezeigten Ausführungsform, wobei die beweglich angeordneten sich Rostblöcke in einer Mittelstellung befinden;

Fig. 13c

vier treppenartig übereinander angeordneten Rostblöcken gemäss der in Fig. 6 gezeigten Ausführungsform, wobei die beweglich angeordneten Rostblöcke maximal eingefahren sind;

Fig. 14a

vier nebeneinander angeordnete Rostblöcke in perspektivischer Ansicht gemäss in Fig. 9 gezeigter Ausführungsform mit muldenförmigen Vertiefungen;

Fig. 14b

in Vergrösserung einen der muldenförmigen Vertiefungen gemäss Fig. 14a; und

Fig. 15

Ausschnitt eines Treppenrosts mit ortsfesten und beweglich angeordneten Rostblöcken.

The grate block according to the invention will be explained in more detail below with reference to exemplary embodiments shown in the drawings. It shows purely schematically:

Fig. 1

a first embodiment of the grate block in longitudinal section;

Fig. 2

a further embodiment of the grate block in longitudinal section;

Fig. 3

a further embodiment of the grate block in longitudinal section, with an elongated upper wall;

Fig. 4

a further embodiment of the grate block in longitudinal section with a substantially S-shaped cooling channel of medium length relative to the limited distance from the front and the rear wall;

Fig. 5

a further embodiment of the grate block in longitudinal section with a short substantially S-shaped cooling channel;

Fig. 6

a further embodiment of the grate block in longitudinal section with a short substantially S-shaped cooling channel and additional staggered deflection webs;

Fig. 7

an embodiment of the grate block in cross section;

Fig. 8

a further embodiment of the grate block in cross section;

Fig. 9

a further embodiment of the grate block in cross section with a trough-shaped depression on the combustion chamber facing side of the upper wall;

Fig. 10

three juxtaposed grate blocks according to Fig. 7 in cross-section;

Fig. 11

three juxtaposed grate blocks according to Fig. 8 in cross-section;

Fig. 12

three juxtaposed grate blocks according to Fig. 9 in cross-section;

Fig. 13a

four staircase stacked grate blocks according to the in Fig. 6 shown embodiment, wherein the movably arranged grate blocks are maximally extended;

Fig. 13b

four staircase stacked grate blocks according to the in Fig. 6 shown embodiment, wherein the movably arranged grate blocks are in a central position;

Fig. 13c

four staircase stacked grate blocks according to the in Fig. 6 shown embodiment, wherein the movably arranged grate blocks are retracted maximally;

Fig. 14a

four juxtaposed grate blocks in perspective view according to in Fig. 9 shown embodiment with trough-shaped depressions;

Fig. 14b

in enlargement one of the trough-shaped depressions according to Fig. 14a ; and

Fig. 15

Section of a stair grate with fixed and movably arranged grate blocks.

Fig. 1 shows a grate block according to the invention with a block body 5, which is designed as a casting. The block body 5 has an upper wall 10, which forms a bearing surface 15, and a front wall 20. To the front wall 20, a foot 25 is formed. The foot 25 is intended to rest relatively slidably on the support surface 15 of a subsequent grate block 1. On a lower side 30 of the upper wall 10, ie on the side remote from the combustion chamber 2, a wall inlet 35 is arranged, from which a first cooling channel section 40 through the upper wall 10 and the front wall 20 to an outlet opening 45 arranged in the front wall 20 runs. In the embodiment shown, the outlet opening 45 is directed obliquely downward, ie in the direction of the support surface 15 of the subsequent grate block 1. Adjacent to the foot 25 and to the front wall 20 is an inlet opening 50 from which a cooling channel wall 55 spaced from the front wall 20 and the top wall 10 forms a second cooling channel section 60 fluidly connected to the wall inlet 35 with the first cooling channel section 40. In the embodiment shown extend the first and second cooling channel sections (40, 60) do not extend over the entire length of the upper wall 10. The cross-section or cross-sectional area of the in Fig. 1 shown first cooling passage portion 40 and the second cooling passage portion 60 varies in the course of the two cooling passage sections. However, the cross section can also be kept constant.

The grate block according to the invention has, for example, the following dimensions, a length of 500 mm to 700 mm, a height of approximately 150 mm and a width of approximately 100 mm.

Fig. 2 shows a further embodiment of the inventive grate block. In this embodiment, the grate block has a rib 65, a rear wall 75. The rib 65 is formed on the front wall 20, the upper wall 10, the cooling channel wall 55 and the rear wall 75 and arranged substantially perpendicular thereto. The rib 65 extends from the front wall 20 to the rear wall 75. The rear wall 75 is provided with a hook 80. By means of this hook 80, the grate block 1 is mounted on a block holder tube (not shown here). The grate block 1 has on the circumference no exact cuboid shape. Rather, it is chamfered at the collision of the upper wall 10 with the front wall 20.

Fig. 3 shows a further modified embodiment of the inventive grate block 1. The upper wall 10 and the front wall 20 have circumferentially turn on a chamfer, which is extended by a nose 85 on the firebox 2 facing outer side 21 of the front wall 20 addition. The nose 85 thus protrudes the outer side 21 of the front wall 20 addition. Thus, the outlet opening 45 is substantially vertically downwards in the direction of the support surface 15 of a subsequent grate block. 1

Fig. 4 shows another embodiment of a grate block 1 with a block body 5. The block body 5 has a front wall 20, an upper wall 10 and a rear wall 75 on. To the front wall 20 is a foot 25 and to the rear wall 75, a hook 80 is formed. From a wall inlet 35, a first cooling channel section 40 extends through the top wall 10 and the front wall 20 to an outlet opening 45. From an inlet opening 50 located adjacent to the foot 25 and front wall 20, one extends from the front wall 20 and the upper wall 10 spaced cooling channel wall 55, which forms a wall inlet 35 with the first cooling channel portion 40 flow-connected second cooling channel portion 60. The first and second cooling channel sections (40, 60) extend over only a portion of the length of the top wall 10. In the illustrated embodiment, they extend approximately over half the length of the top wall 10, and thus over a region of higher thermal stress ,

Fig. 5 shows an embodiment of a grate block according to the invention analogous to that in FIG Fig. 4 shown embodiment. In this case, the first cooling channel section 40 and the second cooling channel section 60 extend only over an area adjacent to the front wall 20 of approximately one third of the length of the front wall 10.

Fig. 6 shows another embodiment of a grate block according to the invention 1. The formed as a cast block body 5 has an upper wall 10, which forms a support surface 15, and a front wall 20, wherein the front wall 20, a foot 25 is formed. The foot 25 is intended to rest relatively slidably on the support surface 15 of a subsequent grate block 1. On a lower side 30 of the upper wall 10, on the side remote from the combustion chamber 2, a wall inlet 35 is arranged, from which a first cooling channel section 40 extends through the upper wall 10 and the front wall 20 to an outlet opening 45 arranged in the front wall 20 , In the embodiment shown, the outlet opening 45 is directed obliquely downward, ie in the direction of the support surface 15 of the subsequent grate block 1. Adjacent to the foot 25 and to the front wall 20 is an inlet opening 50 from which a cooling channel wall 55 spaced from the front wall 20 and the top wall 10 forms a second cooling channel section 60 fluidly connected to the wall inlet 35 with the first cooling channel section 40. In the embodiment shown, the first and second cooling channel sections (40, 60) extend only over approximately the front third of the length of the top wall 10. The cross-section or cross-sectional area of the in Fig. 6 shown first cooling passage portion 40 and the second cooling passage portion 60 varies in the course of the two cooling passage sections. Starting from the inlet opening 50, the second cooling channel section 60 has a narrow cross-section along the front wall 20, which then widens several times towards the wall inlet 35. In the first cooling channel section 40 narrows the extended cross section toward the outlet opening 45 again to approximately the same narrow cross-section as it extends in the second cooling channel section 60 along the front wall. The block body 5 also has a rib 65 which is formed on the front side 20, the upper side 10 and a rear side 75 and arranged substantially perpendicular thereto. The rear wall 75 is also equipped with a hook 80 in this embodiment. On the rib 65, a Umlenksteg 70 is formed, which is arranged substantially perpendicular to the rib 65.

In the embodiment shown, a total of 5 deflecting webs 70 are present, which run obliquely downwards in a direction L from above. The direction L also corresponds to the conveying direction of the waste resting on the bearing surface 15 (not shown). The deflecting webs 70 are arranged alternately offset. That is, the deflecting webs 70 are formed either with its upper end on the underside 30 of the upper wall 10 or with its upper end so spaced from the lower side 30 of the upper wall 10, so that the lower end 72 of the Umlenkstege 70 with the bottom surface 26 of the foot 25 is in a plane.

Fig. 7 shows a cross section through a grate block according to the invention 1. The block body 5 has an upper wall 10 with a support surface 15 and a bottom 30 and a rib 65. Through the upper wall 10 extends a first cooling passage portion 40. The spaced from the upper wall 10 cooling passage wall 55 forms together with this upper wall 10 a second cooling passage portion 60. In the embodiment shown, the rib 65 is centrally located.

Fig. 8 shows a further cross section through a grate block 1. Here are from the block body 5, only the upper wall 10 with the extending through the upper wall 10 first cooling channel portion 40, which is divided as shown here in cross section in 4 smaller cooling channel sections, and from the upper wall 10 spaced cooling channel wall 55 and the second cooling channel portion 60 visible. Also shown is the rib 65, which in turn is disposed in the center of the block body 5 and substantially perpendicular thereto.

Fig. 9 shows another embodiment of a grate block 1 according to the present invention. The block body 5 in turn has a support surface 15 forming an upper wall 10 with a bottom 30, a spaced from the upper wall 10 cooling channel wall 55 and a centrally disposed rib 65. Also visible are the first cooling passage section 40 extending through the upper wall 10 and the second cooling passage section 60 formed by the cooling passage wall 55 and the upper wall 10. In addition, the upper wall has a trough-shaped depression 90. This recess 90 extends as shown in Fig. 14a can be seen, only over approximately the front third of the grate block 1. In this trough-shaped depression slag accumulates, resulting in a shielding of the grate block relative to the hearth 2. In the area of this shield, the thermal load of the grate block 1 by a reduced heat input is smaller.

Fig. 10 shows with three juxtaposed grate blocks 1 according Fig. 7 a section of a grate block row in cross section. At this time, the first cooling passage portion 40 and the second cooling passage portion 60 become formed together by two adjacent grate blocks 1. While the first cooling passage portion 40 passes through the upper wall 10, the second cooling passage portion 60 is formed by the cooling passage wall 55 spaced from the upper wall 10 together with this upper wall 10. The lateral boundary of both the first cooling channel section 40 and the second cooling channel section 60 is formed by the ribs 65 of two adjacent grate blocks 1, which are arranged substantially centrally relative to the individual grate block.

Fig. 11 shows with three juxtaposed grate blocks 1 according Fig. 8 a section of a grate block row in cross section. Visible are the block body 5 of each of the three grate blocks 1 shown, the upper wall 10, the spaced therefrom cooling channel wall 55 and the turn substantially centrally disposed rib 65. The first cooling channel section 40 extends through the upper wall 10. Also visible is again the breakdown of first cooling duct section into 4 smaller cooling duct sections which extend through the upper wall 10 and through the front wall 20 and open into the outlet openings arranged in this front wall 20. The second cooling channel section 60 is formed jointly by two adjacent grate blocks 1.

Fig. 12 shows with three juxtaposed grate blocks 1 according Fig. 9 a section of a grate block row in cross section. The first cooling passage section 40 and the second cooling passage section 60 are jointly formed by two adjacently arranged block bodies 5 of the grate blocks 1. During the first cooling passage portion 40 passes through the top wall 10, the second cooling passage portion 60 is formed by the cooling passage wall 55 spaced from the top wall 10 and the top wall 10. The lateral boundary of both the first cooling channel section 40 and the second cooling channel section 60 is formed by the ribs 65 of two adjacent grate blocks 1, which are arranged substantially centrally relative to the individual grate block. The trough-shaped depression 90 in the upper wall 10 of the block body 5 is also visible.

The Figures 13a, 13b and 13c show in cross section four step-like successively arranged grate block rows 100, 101, 102 and 103, each comprising a plurality of juxtaposed grate blocks 1. The illustrated embodiment of the grate blocks 1 corresponds to that of Fig. 6 , The grate block rows 100 and 102 are fixed grate block rows, while the grate block rows 101 and 103 are arranged to be movable. The grate blocks 1 of the movable grate block rows 101 and 103 are in the Figs. 13a, 13b and 13c to be seen in different positions. In Fig. 13a are the grate blocks 1 of the movable grate block rows 101 and 103 in the direction L, which corresponds to the conveying direction of the waste, maximally extended. In this case, a meandering channel 110 is formed by the Umlenkstege 70 of the grate blocks 1 of the movable grate block rows 101 and 103 with a channel inlet opening 115 through which the gaseous cooling medium, for example, the primary air flows. In Fig. 13b the grate blocks 1 of the movable rows of grate blocks 101 and 103 are shown in the direction L in a central position, which is located between the in Fig. 13a shown maximum extended position and the in Fig. 13c shown in is located to the direction L opposite direction maximum retracted position. As a result, both the length of the meandering channel 110 and the position of the channel inlet opening 115 changes. As a result, the grate blocks 1 of the movable grate block rows 101 and 103 are always cooled in the area exposed to the waste in the firing space 2.

Fig. 14a shows a grate block row consisting of four adjacent grate blocks 1 in a perspective view. The upper wall 15 forming a bearing surface 15, the front wall 20 and the foot 25 formed thereon are visible. Also shown are the rear wall 75 provided with a hook 80 and the rib 65 centrally located relative to the individual grate block 1. Only partly visible is the cooling channel wall 55 spaced from an inlet opening 50 from the front wall 20 and the top wall 10 extends to a wall inlet 35 and forms a second cooling passage section 60 which is fluidly connected to a first cooling passage section 40 at the wall inlet 35. The first cooling channel section 40 extends from the wall inlet 10 through the upper wall 10 and the front wall 20 toward outlet openings 45. In the illustrated embodiment, the block body 5 has trough-shaped depressions 90 in the upper wall 10. These trough-shaped depressions 90 are arranged in the upper wall 10 in the region of the grate block 1 adjoining the front wall 20. This area is constantly exposed to waste during operation.

Fig. 14b shows in an enlarged section of the Fig. 14a arranged in the upper wall 10 trough-shaped depressions 90th

Fig. 15 shows a combustion grate with step-like successively arranged grate blocks 1 in longitudinal section as it is known from the prior art. The grate blocks 1 are not arranged horizontally, but rise in the direction L obliquely at the top.

Claims (12)

Air-cooled grate block of a grate for the thermal treatment of waste, in which the grate blocks (1) are arranged in a staircase superimposed, with a designed as a cast block body (5), a support surface (15) forming the upper wall (10) and a front wall (20), to which a foot (25) is formed, wherein from a on a bottom (30) of the upper wall (10) arranged wall inlet (35), a first cooling channel portion (40) through the upper wall (10) and the front wall (20) extends to an outlet opening (45) arranged in the front wall (20), characterized in that an inlet opening (50) arranged from an inlet opening (50) arranged adjacent to the foot (25) and the front wall (20) emanates from and the cooling chamber wall (55) spaced apart from the front wall (20) and the upper wall (10) forms a second cooling channel section (60) which is connected to the first cooling channel section (40) at the wall inlet (35). Grate block according to claim 1, characterized in that the first cooling channel channel portion (40) and the second cooling channel portion (60) have a varying in cross section. Grate block according to one of the preceding claims, characterized in that extending in the longitudinal direction of the block body (5), on the upper wall (10), and the front wall (20) integrally formed and arranged substantially perpendicular to this rib (65) , Grate block according to claim 3, characterized in that the rib is a central rib. Grate block according to one of the preceding claims, characterized in that the first cooling channel section (40) and the second cooling channel section (60) extend over the entire length of the upper wall (10). Grate block according to one of claims 1-4, characterized in that the first cooling channel section (40) and the second cooling channel section (60) are only over a portion of the length of the upper wall (10), preferably over 10% -90%, particularly preferred over 30% -70%. Grate block according to one of the preceding claims, characterized in that the cross section of the second cooling channel section (60) increases from the inlet opening (50) towards the wall inlet (35) and the cross section of the first cooling channel section (40) from the wall inlet (35) to the outlet opening ( 45) down. Grate block according to one of claims 3 to 7, characterized in that the block body (5) on the rib (65) integrally formed, substantially perpendicularly projecting from this Umlenkstege (70), wherein the Umlenkstege (70) are arranged offset from one another. Grate block according to claim 8, characterized in that the deflecting webs (70) form a meandering channel (110) connected in flow to the second cooling channel section (60) at the inlet opening (50) and having a channel inlet opening (115) Position of the channel inlet opening (115) from a relative position of the grate block (1) to a subsequent direction in a direction L grate block (1) is dependent. Grate block according to one of the preceding claims, characterized in that the upper wall (10) has a trough-shaped depression (90) facing the firing chamber (2). Grate comprising grate blocks according to one of the preceding claims. A grate according to claim 9, comprising a plurality of stationary grate block rows and a plurality of movable grate block rows arranged alternately, wherein a plurality of grate blocks are hung side by side on a block holder tube and fixedly connected to each other forming the respective grate block row, characterized in that both the stationary and also the movable grate block rows are formed by the grate blocks according to one of claims 1-10.

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