EP3967927A1 - Water-cooled grate block for a combustion engine - Google Patents

Abstract

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 cast part with an outer bearing surface (7) for the waste to be treated, one arranged directly below the bearing surface (7). flat cavity (50) 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 circulate 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 front area (11) of the cavity (50) for distributing the fluid fed through the fluid supply line (52) into the cavity (50). cooling fluids.

Description

Combustion grates for the large-scale incineration of waste have been known to those skilled in the art for a long time. Such incineration grates may be in the form of shear incineration grates, which include moving parts to perform stoking. In this case, the material to be burned is conveyed in the transport direction from an inlet-side end of the combustion grate to an outlet-side end and is burned at the same time. In order to supply the incineration grate with the oxygen required for the incineration, appropriate air ducts are provided which pass through the incineration grate and via which the air--also called primary air--is introduced.

A frequently used incineration grate is the so-called stepped grate. This comprises grate blocks arranged side by side, each of which forms a row of grate blocks. The rows of grate blocks are arranged one above the other in a stair-like manner. In the case of so-called pusher grates, the front end of a grate block, viewed in the direction of thrust, rests on a bearing surface of the grate block that is adjacent (below) in the transport direction and is moved on this bearing surface with a corresponding thrust movement.

Due to the fuel being conveyed over the grate blocks, the former are generally exposed to a relatively high level of wear. In the front area of each grate block, the material to be burned is lifted off the support surface ejected via a corresponding ejection edge (also known as a nose) onto the contact surface of the subsequent or adjacent grate block below. The mechanical abrasion caused by the material to be burned is particularly high in this front end area of the support surface.

Due to the high temperatures during combustion or in the combustion chamber, the grate blocks are also exposed to very high thermal loads. During normal operation of the combustion grate, this thermal load is particularly high in the area of the supporting surface, although the combustion material lying on the grate block has an insulating effect to a certain degree. Temperature peaks and the associated load peaks occur in particular when the fuel is unevenly distributed on the combustion grate and as a result only a thin insulating layer forms in some places or when this insulating layer is completely absent. The thermal stress promotes abrasion erosion and chemical reactions occurring at the bearing surface which further damage the bearing surface. This all ultimately leads to a reduction in the life of the grate block.

In order to reduce the thermal load, the grate bars are normally cooled with a coolant or cooling fluid from below, ie on the side of the combustion grate opposite to the combustion. Water or air are usually used as coolants, which is why the term air or water-cooled grate blocks is often used. The type of cooling or the Coolant supply is the subject of a large number of patent applications or patents:
the EP 1 760 400 B1 discloses a water-cooled grate element made of cast steel with deflection elements which form meandering water supply channels. The disadvantage of such a water flow is that the cooling capacity is impaired directly above the deflection elements, since the cooling liquid has no contact with the upper wall there and therefore cannot transport away the heat generated by the combustion. As a result, a burn surface with so-called “heat hotspots” develops at these points.

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

EP 0 811 803 B1 discloses cooled grate blocks in which the cooling lines run at right angles to the feed direction and are deflected outside the grate blocks by means of brackets.

When cooling using the known cooling channels or cooling lines, the entire area of the combustion surface is by far not covered, which promotes the formation of the "heat hotspots" mentioned above.

In order to achieve the highest possible cooling performance, the focus is on maximizing the surface area available for heat exchange. With liquid coolants, the flow should be as even as possible of the coolant is of central importance. Otherwise, turbulence and bubble formation can occur in the cooling lines, which reduces the cooling capacity of the grate blocks.

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

This object is achieved 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 set out in the dependent claims.

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 usually arranged in a stair-like manner one above the other and are designed in such a way that they shift and convey the material to be burned during combustion by means of thrust movements performed relative to one another. The grate block according to the invention comprises a block body designed as a cast part with an upper wall. The upper wall forms an outer support surface for the waste to be treated, running at least partially parallel to a longitudinal axis L of the block body. Furthermore, the grate block according to the invention comprises a flat cavity arranged directly below the support surface for receiving a cooling fluid. The planar cavity is thereby on the upper side by the upper wall, delimited on the front side by a front wall, on the underside by a base, on the back by a rear wall and on the sides 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 discharge line, both of which are connected to the cavity, and at least one deflection element arranged in the cavity to direct the cooling fluid in the cavity from the fluid supply line to the fluid discharge line. In a front area of the cavity of the grate block according to the invention there is also a distribution element for distributing the cooling fluid fed into the cavity through the fluid supply line.

In the context of the present invention, grate blocks lying one on top of the other in a step-like manner are defined as grate blocks on a grate which are arranged like the steps of an ascending or descending staircase.

The term “thrust movements that can be carried out relative to one another” is understood to mean thrust movements that can be carried out parallel to the longitudinal axis of the grate consisting of grate blocks. In the case of a step-shaped grate, the direction of movement runs parallel to the incline or rise of the grate.

The "longitudinal axis of the grate block" refers to an axis which extends parallel to the axis of the stepped grate - ie from the front wall to the rear wall of the grate block - and thus runs parallel to the thrust direction of the waste to be treated. If the grate block is aligned so that the longitudinal axis and a width axis running at right angles thereto are arranged in the horizontal plane, then the front wall is preferably arranged at least approximately in the vertical plane.

In the context of the present application, “bearing surface” means a surface which is arranged on the outer upper side, ie on the opposite side of the cavity, and on which the waste (fuel) intended for thermal treatment rests. As mentioned at the outset, this bearing surface in incineration plants is known to be exposed to increased thermal stress and is susceptible to erosion and caking of combustion products.

In the context of the present application, a flow of cooling fluid—preferably water—is defined as a fluid flow or cooling fluid flow, which is conducted through the cavity from the fluid supply line to the fluid discharge line or vice versa.

In the context of the present invention, the term “flat cavity” is understood to mean that the cavity has a shape whose extension in the horizontal direction (length and width) is greater than in the vertical direction (height). The cavity preferably has a cuboid shape, at least in sections, with the largest surface parallel to the bearing surface.

In the following, fluid supply line and fluid discharge line are understood to mean lines which are suitable for conducting cooling fluid into the cavity and for discharging it from it. It is explicitly a possibility here mentioned that the fluid stream can flow in both directions, i.e. it can be supplied and discharged alternately through both lines.

For the purposes of the present invention, the front side or front side is understood to mean the side in the area of the front wall.

In terms of the present invention, an obstacle is defined as a distribution element, which is designed in such a way that it allows a restriction and/or a change in direction of the flow and thus a distribution of the inflowing cooling fluid. The cooling fluid is preferably distributed before or in the area where the cooling fluid enters the planar cavity. The distribution element can have different shapes, as will be explained in more detail below.

The grate block according to the invention has the advantage over the prior art that the flow of cooling fluid flowing into the cavity can be distributed evenly over the width of the cavity thanks to the distribution element. This means that the formation of cooling fluid turbulence and foam formation can be reduced or even completely prevented, which leads to an increased cooling capacity of the grate block. The increased cooling capacity has the advantage that the thermal load and wear on the grate blocks is reduced and, moreover, fewer burned-out substances are baked onto the grate blocks, which means that they have to be cleaned and serviced less frequently. This ultimately leads to less maintenance work to be carried out, and thus the incinerator can be operated more economically.

The distribution element preferably extends at least in sections along a width axis which runs at least approximately parallel to the front wall. This enables a regular distribution of the cooling fluid over the width of the planar cavity (or a compartment of the planar cavity).

In a preferred embodiment of the grate block, the flat cavity is connected to a front chamber. Said chamber preferably extends essentially parallel to - and preferably at least over half the length of - the front wall. It is preferably designed in such a way that the cooling fluid flows into the flat cavity or the cooling fluid flows out of the flat cavity through the chamber. Such an embodiment is in the attached figure 2 shown.

The flat cavity and the chamber are preferably connected to one another via a plurality of inflow openings. This preferably enables a pre-distribution of the cooling fluid before it hits the distribution element and thus also contributes to a better distribution of the cooling fluid in the planar cavity.

Also, feeding the cooling fluid through the chamber into the cavity allows the front wall, which is also 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 bearing surface, its cooling helps to prevent caking of fly ash or other combustion products.

In a preferred embodiment of the grate block, the flat cavity has a partition wall extending from the bottom to the top wall. This dividing wall preferably extends from the front wall in the direction of the rear wall of the cavity and preferably forms a passage in the area of the rear wall, so that the cavity is divided into two compartments that are connected in a fluid-conducting manner.

Because of the dividing wall, the fluid stream thus preferably flows through a first compartment of the cavity, which extends from the front wall along the longitudinal axis over a desired length of the cavity. In the area of the rear wall, the fluid flow is directed through the passage, whereby it is deflected and flows back through a second compartment adjacent to the first compartment in the opposite direction, i.e. towards the front wall. Thanks to the partition wall, the rear areas of the cavity are also sufficiently supplied with fresh cooling fluid, so that the cooling capacity is also guaranteed in these areas.

It has been found that in known water-cooled grate blocks, air is conveyed into the cavity by the flow of cooling fluid and can remain there as air pockets at best in corners or poorly accessible places. Due to the lower density of air compared to water, any air pockets tend to accumulate at the top of the cold room and as the Since the thermal conductivity of air is significantly lower than that of water, such air inclusions lead to a reduced cooling capacity of the grate block. In the case of a liquid cooling fluid, the grate block according to the invention therefore preferably comprises at least one ventilation opening for ventilating the cavity or the compartments, in order to convey any such air inclusions out of the grate block. At the same time, the venting of the cavity or the compartments prevents air from being carried along with the cooling fluid over the entire length of the fluid flow.

If the cavity is divided into compartments by a partition, the ventilation opening is preferably formed in the partition, preferably in the area of the front wall, in order to enable the cavity or the compartments created by the partition to be vented.

The ventilation opening preferably has a diameter of 2-12 mm, particularly preferably 4-5 mm. This size makes it possible for the grate block, including the ventilation opening, to be produced using the known casting processes.

In a preferred embodiment of the grate block, the dividing wall runs at least approximately parallel to one of the side walls and is preferably arranged centrally in the cavity. In this embodiment, the dividing wall thus divides the flat cavity into two compartments that are at least approximately the same size. This ensures that the fluid stream flows evenly through the cavity or through the compartments and is not accelerated or accelerated due to a change in the geometry of the cavity or compartment is slowed down. This prevents turbulence from occurring as a result of acceleration or deceleration of the fluid flow within the cavity or the compartments.

The fluid supply line and the fluid discharge line are preferably connected to the flat cavity in the area of the front wall. The connection of the fluid supply line and the fluid discharge line to the cavity in the front or face area frees up the largest possible space underneath the block body.

Both the fluid supply line and the fluid outflow line preferably have an inner diameter of 20-32 mm, preferably 22-30 mm and particularly preferably 26-28 mm. Line diameters of this size have the advantage that, for the usual cooling fluid circulation volume, there is a flow rate at which the flow automatically vents the entire line 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.

In a preferred embodiment of the grate block, the distribution element is designed in such a way that it only allows a restricted flow of cooling fluid past the distribution element - or over it - in order to enable an even distribution of the cooling fluid within the cavity. This even distribution of the cooling fluid flow enables increased cooling performance, since turbulence in the cooling fluid and foaming are reduced or prevented.

In a specific preferred embodiment, the cooling fluid flowing in through the fluid supply line first strikes the distribution element, as a result of which turbulence is calmed. The water can preferably flow through openings in the distribution element (if present) or over or around it.

In a preferred embodiment of the grate block, the distribution element is designed in the form of a baffle plate or a baffle plate. Further preferred embodiments include a distribution element which is designed as a hump, screen, perforated plate or crossbar. The longitudinal axis of the distribution element preferably runs approximately parallel to the front wall.

If the distribution element is designed as a hump, this means that the distribution element has a hill-shaped or hill-shaped cross section in the width direction, ie parallel to the front wall. The cooling fluid thus flows perpendicularly to the front wall and in the opposite direction to the direction of movement of the combustion material over the distribution element.

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 guided.

In the case of a transverse beam, it is understood here that the distribution element forms a wall or a beam, over or under which the cooling fluid can flow. The bar preferably extends along the entire length Width of the grate block and at least approximately parallel to the front wall.

As mentioned above, the distribution element enables the cooling fluid flow to be distributed evenly over as far as possible the entire width of the cavity and, if the cavity has compartments, over the width of the compartments. This uniform distribution of the flow of cooling fluid allows for increased cooling performance, since turbulence in the cooling fluid and the formation of foam can be reduced or prevented. The distribution usually takes place in the area where the cooling fluid enters the cavity and can be achieved with the aid of a distribution element of simple design. The distribution element can preferably be cast at the same time or used later as a separate component.

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.

In a preferred embodiment of the grate block, the distribution element is connected to the bottom and/or to the top wall. If the distribution element is designed as a crossbar, this preferably forms a slit-like fluid passage opening with the top wall and/or the bottom. The fluid passage opening is particularly preferably formed between an upper edge of the crossbar and the upper wall. The fluid passage opening preferably has a clear width of 1 to 15 mm, preferably 2 to 10 mm and particularly preferably 3 to 6 mm.

With regard to an even distribution of the cooling fluid flow entering the cavity, the above-described embodiment of the distribution element as a crossbar with the above properties has proven to be particularly effective.

In a further preferred embodiment of the grate block, the distribution element is located in the mouth area of the at least one inflow line. It was found that turbulence in the cooling fluid occurs particularly frequently when it enters the cavity—that is, in the mouth area of the inflow line. Since the thermal load in the front area of the grate block is particularly high, a reduced cooling capacity due to air pockets has a double negative effect there. With an arrangement of the distribution element in the mouth area of the inflow line, rapid calming is achieved when the cooling fluid enters the cavity.

Preferably, the distribution member includes a hump, ridge, or hill-like obstruction that restricts or diverts the flow of cooling fluid from the fluid supply line. The distribution element preferably has a height of 5-15 mm, particularly preferably 8-12 mm and very particularly preferably 10 mm and a width of preferably 20-40 mm, particularly preferably 25-35 mm and particularly preferably 30 mm.

The combination of a hump-shaped or ridge-like or hill-like distribution element, which is located in the mouth area of the inflow line, has proven to be the highest in the distribution of the cooling fluid flow in the cavity proven effective. Furthermore, the production of such a distribution element can be easily accomplished with the known casting methods and is therefore preferred.

If the distribution element is designed as a crossbar, the distribution element preferably has an area which is at least 50% of the vertical cross-sectional area of the cavity or of the respective compartment.

The cross bar preferably has a thickness of 2 mm to 10 mm and a length of 50 mm to 250 mm.

If the distribution element is designed as a crossbar, this 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 of the respective compartment.

In a preferred embodiment of the grate block, the top wall and/or the front wall has at least one air supply opening. This air supply opening makes it possible to transport additional air into the combustion chamber in order to ensure optimal combustion. Starting from the top wall, the air inlet opening can expand concentrically (vulcano-shaped) downwards, which prevents clogging of the air inlet opening with thermally treated waste. Such volcano-shaped air supply openings are preferably located in the top wall. Furthermore, they preferably have an oval opening cross-section with a diameter of 33-45 mm by 4-12 mm. In addition, they preferentially expand in direction of the bottom plate at an angle of 18 - 22° to a smaller diameter of 22 - 28 mm.

The block body is preferably made in one piece as a casting and preferably also includes a piece of the bottom. The base plate, which preferably at least partially forms the base, is preferably welded to the block body and thus delimits the cavity. This means that a part of the base is preferably designed as an integral part of the block body and the cavity is also at least partially delimited on the base side by the base plate. This enables the cavity to be manufactured easily, since the cast part can be cast in one step and the cavity can then be formed by attaching, preferably by welding, the base plate. Such a manufacture of the block body is particularly favorable and makes the block body particularly durable and low-maintenance. The person skilled in the art is of course aware that the cast part can be further processed before the base plate is fastened, for example by using a blasting medium.

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

The cavity should preferably cover at least the bearing surface for the waste to be treated, so that there is no thermally stressed, uncooled surface of the block body.

The cooling fluid preferably has a temperature of 20-140° C. during operation of the grate block, ie during the incineration of high-calorific waste such as household waste or commercial waste, whereby operating temperatures for the grate block of up to 250° C. are achieved. Next is used as a cooling fluid - preferably water - from a closed circuit to prevent the entry of oxygen and thus the formation of corrosion. When water is used as the cooling fluid, this preferably has no or only a small proportion of lime.

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

Fig. 1

eine perspektivische Ansicht einer Ausführungsform eines erfindungsgemässen Rostblocks;

Fig. 2

eine perspektivische Ansicht einer Ausführungsform eines flächigen Hohlraums;

Fig. 3

eine perspektivische Ansicht einer Ausführungsform des Rostblocks aus Fig. 1 mit dem flächigen Hohlraum aus Fig. 2;

Fig. 4a

einen Längsschnitt entlang der Längsachse L durch eine Ausführungsform eines vorderen Bereichs des Blockkörpers aus Fig. 1;

Fig. 4b

einen Längsschnitt entlang der Längsachse L durch eine Ausführungsform eines vorderen Bereichs des Blockkörpers aus Fig. 1;

Fig. 5

einen Querschnitt entlang Breitenachse Q durch eine Ausführungsform eines vorderen Bereichs des Blockkörpers aus Fig. 1; und

Fig. 6

einen Längsschnitt entlang der Längsachse L durch eine Ausführungsform des Blockkörpers aus Fig. 1.

The invention is explained in more detail below with reference to some exemplary embodiments illustrated in the figures. If alternative embodiments differ only in individual features, the same reference numbers were used for the features that remained the same. They each show purely schematically:

1

a perspective view of an embodiment of a grate block according to the invention;

2

a perspective view of an embodiment of a planar cavity;

3

Figure 12 shows a perspective view of one embodiment of the grate block 1 with the flat cavity 2 ;

Figure 4a

1 shows a longitudinal section along the longitudinal axis L through an embodiment of a front region of the block body 1 ;

Figure 4b

1 shows a longitudinal section along the longitudinal axis L through an embodiment of a front region of the block body 1 ;

figure 5

Figure 12 depicts a cross section along width axis Q through one embodiment of a forward portion of the block body 1 ; and

6

shows a longitudinal section along the longitudinal axis L through an embodiment of the block body 1 .

the inside 1 The grate block 1 according to the invention shown is used for the thermal treatment of waste as combustion material (not shown), which is moved or conveyed in a movement direction B over the grate. 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 Section 9 of the block body 3 extends in the direction of a front section 11 of the block body 3 . Furthermore, the block body 3 comprises in the front area 11 a rounded overhang 13 (hereinafter referred to as a nose), which connects the front area 11 to a front wall 15 .

In a grate arrangement, not shown, in which several individual grate blocks 1 are arranged in a stair-like manner one above the other, a sliding surface 17 adjoining the front wall 15 rests on the bearing surface 7 of another grate block (not shown). Thermally treated waste is transported in the direction of movement B with the aid of pushing movements carried out relative to one another. For this purpose, the sliding surfaces 17 slide on the bearing surfaces 7 of the grate blocks arranged underneath (not shown). The relative thrust movements are carried out along the longitudinal axis L and driven by a drive device, not shown, which transmits the movement via a bracket 19 to the block body. In such a grate arrangement, several grate blocks can lie side by side, so that the side walls 6 of the grate block 1 adjoin the side walls of other grate blocks.

The block body 3 includes air supply openings 21, 23 arranged in the front wall 15 and the top wall 5, through which the thermally treated waste can be supplied with air to promote incineration. Embodiments which have no air supply openings are also conceivable, but are not shown here. The air supply openings 23 in the top wall 5 are preferably designed as passages that widen downwards, so that parts of the waste to be treated do not get caught in the opening if they pass through.

The block body 3 also includes a flat cavity 50. As in FIG 2 shown, the flat cavity 50 opposite the top wall 5 of the block body 3 is delimited by a bottom 51 and a bottom plate 53 . In this case, the cavity 50 further comprises a fluid supply line 52 and a fluid discharge line 54 which are each connected to a chamber 56 . The chamber 56 extends substantially parallel to the front wall 15 ( 1 ) and is connected to the flat cavity 50 via inflow openings 58 . The planar cavity 50 further comprises a partition wall 60, which extends from the front wall (reference number 15 in 1 ) toward a rear wall 68 ( 3 ) extends and forms a passage 64 so that the cavity 50 is divided into two compartments 62 .

3 shows a view from below of a section through the grate block 1 1 in connection with the in 2 described flat cavity 50. The base plate 53 from 2 , which delimits the cavity 50, has been removed here. The flat cavity 50 includes deflection elements 66, which the fluid flow from the fluid supply line 52 ( 2 ) to fluid drain line 54 ( 2 ) redirect. In 3 It is also clearly visible how the flat cavity 50 in the rear area 9 of the block body 3 is delimited by the side walls 6 and the rear wall 68 . Next is in 3 clearly visible that the air supply openings 23 pass through the flat cavity 50 from the top wall.

Figure 4a and 4b show a longitudinal section along the longitudinal axis L through the front area of the block body 1 with the air supply openings 21 in the front wall 15. It can also be seen that the partition 60, which divides the cavity 50, has an opening 70, which serves to vent the compartments 62 created by the partition 60. The inflow opening 58 comprises a distribution element 74 in an opening area 72 facing the cavity 50, which is designed here as a hump-like or hill-like obstacle. The fluid flow, which is conducted via the inflow opening 58 into the cavity 50, is distributed using the distribution element 74 so that no turbulence forms within the planar cavity 50, which would lead to foam formation or air bubbles and thus to a reduced cooling capacity. The floor 51 delimits the cavity 50 at the bottom. The bottom plate 53 is not shown 2 , which would connect to the ground in the longitudinal direction L. The distribution element 74 could also be designed as a crossbeam (not shown) instead of the hump-like or hill-like obstacle.

figure 5 shows a cross section through the front wall 15 with the 2 Chambers 56 shown, in which the fluid supply line 52 and the fluid discharge line 54 open. The cooling fluid flows through the fluid supply line 52 into the chamber 56 and is distributed via the inflow openings 58 in the cavity (not shown). The cooling fluid flows after the cavity has passed through the inflow openings 58' into the chamber 56' and exits the block body 3 through the fluid outflow line 54. The fluid outflow line 54 can be connected to a further fluid supply line of a further block body (not shown).

The block bodies shown have a length in the longitudinal direction L of 400-800 mm, preferably 500-750 mm and particularly preferably 650-700 mm. The block bodies shown have a width in the width direction Q of 280-500 mm, preferably 320-460 mm and particularly preferably 380-420 mm. The block bodies shown have a height of 100-200 mm, preferably 130-180 mm and particularly preferably 150-160 mm. The block body is preferably made from low-alloy to high-alloy cast steel. Compared to unalloyed cast steel, low to high-alloy cast steel also contains varying proportions of alloying elements such as chromium, nickel, molybdenum, vanadium, tungsten and others. The block body is preferably produced by means of a casting or injection molding process. The inflow openings preferably have a diameter of 12-28 mm and particularly preferably a diameter of 16-22 mm.

figure 6 shows a longitudinal section along the longitudinal axis L through the block body 3 1 , wherein the distribution element in a front region 76 of the cavity 50 is not shown. The bottom 51 is formed as an integral part of the block body 3 and, together with the bottom 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 bottom plate 53 has it similar to the top wall 5, the air supply openings 21 on. The air supply openings 21 widen concentrically from the top wall 5 to the bottom plate 53 .

Claims (16)

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 in a stepped manner one above the other and are designed in such a way that the combustible material is shifted and conveyed during combustion by means of thrust 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 bearing surface (7) for accommodating a cooling fluid, which flows through the upper wall (5) on the upper side, through a front wall (15) on the front side, through a bottom (51) on the lower side, through a rear wall (51) on the rear side wall (68) and is delimited laterally by side walls (6), the base (51) being formed at least partially by a base plate (53),
a fluid supply line (52) and a fluid outflow line (54) 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 outflow line (54), and
a distribution element (74) arranged in an end region (76) of the cavity (50) for distributing the fluid fed into the cavity (50) through the fluid supply line (52). Grate block according to Claim 1, characterized in that the distribution element (74) extends at least in sections along a width axis (Q) which runs at least approximately parallel to the front wall (15). Grate block according to Claim 1, characterized in that the flat cavity (50) is connected to a front-side chamber (56) which extends essentially parallel to the front wall (15) and through which the cooling fluid flow into the flat cavity (50) or the cooling fluid is drained from the cavity (50). Grate block according to Claim 3, characterized in that the flat cavity (50) and the chamber (56) are connected to one another via a plurality of inflow openings (58). Grate block according to one of Claims 1 to 4, characterized in that the flat cavity (50) has a partition wall (60) which extends from the bottom (51) to the top wall (5) and which 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-conductively connected compartments (62). Grate block according to Claim 5, characterized in that the partition (60) has an opening (70) in the area of the front wall for venting the cavity (50) or the compartments (62) created by the partition (60). Grate block according to one of Claims 5 or 6, characterized in that the partition wall (60) runs at least approximately parallel to one of the side walls (6). Grate block according to one of Claims 1 to 6, characterized in that the fluid supply line (52) and the fluid discharge line (54) are connected to the flat cavity (50) in the area of the front wall (15). Grate block according to one of Claims 1 to 8, characterized in that the distribution element (74) is preferably 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). Grate block according to one of Claims 4 to 9, characterized in that the distribution element (74) is located in an outlet region (72) of at least one of the inflow openings (58). Grate block according to one of Claims 1 to 10, characterized in that the distribution element (74) comprises a rampart or hill-like projection, which restricts or diverts the flow of cooling fluid from the fluid supply line (52). Grate block according to one of Claims 1 to 11, characterized in that the distribution element (74) is designed in such a way that it only allows a restricted flow of cooling fluid past the distribution element (74) in order to ensure an even distribution of the cooling fluid within the cavity (50 ) to allow. Grate block according to one of Claims 1 to 12, characterized in that the top wall (5) and/or the front wall (15) has at least one air supply opening (21, 23). Grate block according to one of Claims 1 to 13, characterized in that the block body (3) is produced in one piece as a cast part and the base plate (53) is preferably welded to the block body (3) to delimit the cavity (50). Grate block according to one of Claims 1 to 14, characterized in that the cavity (50) extends over at least 2/3 of the length and/or over at least 3/4 of the width of the bearing surface (7). Grate comprising several grate blocks according to one of claims 1 to 15.

Images