EP3798515B1 - Grate block for a combustion grate - Google Patents

Description

The invention relates to a grate block for a combustion grate according to the preamble of claim 1. The invention further relates to a combustion grate comprising at least one such grate block. The invention also relates to the use of said incineration grate for the incineration of waste and a waste incineration plant comprising such an incineration grate.

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 capable of performing stoking. The material to be burned is conveyed from an inlet-side end of the combustion grate to its outlet-side end and is burned in the process. 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 so-called primary air is introduced.

A frequently used incineration grate is the so-called stepped grate. This comprises grate blocks arranged next to one another, each forming a row of grate blocks. The rows of grate blocks are arranged one above the other in a stair-like manner corresponding thrust movement is moved on this support surface. In the case of so-called return grates, the grate blocks are arranged rotated by 180° in relation to the feed grates, viewed in the transport direction of the fuel. Therefore, in the case of reverse thrust grates, the front end of the grate block, viewed in the thrust direction, rests on a bearing surface of the previous grate block in each case. In contrast to push-feed grates, the direction of push in reverse-feed grates is opposite to the transport direction resulting from the inclination of the push-back grate.

A trained as a feed grate combustion grate and a grate block for such a combustion grate is about in EP 1 191 282 described, which relates to a water-cooled grate block. Another combustion grate of the type described is also about in the EP 2 184 540 described which relates to an air-cooled grate block.

Specifically, the in EP 1 191 282 describes a grate block designed as a cast part block body having an upper wall forming a support surface for the waste to be treated and a front wall. In the lower part of the front wall there is a foot designed to rest slidably on the bearing surface of an adjacent grate block in the thrust direction, while in the upper part of the front wall there are openings for introducing the primary air.

Furthermore, rust blocks in the EP2614305A1 and the EP2511609A2 described.

Due to the combustion material conveyed over the grate blocks, these are generally exposed to a relatively high level of wear. Abrasion is particularly high in the area of the front end of the support surface, where the material to be burned from the support surface of the grate block has a A21370WOEP/2 /16.11.2020 corresponding discharge edge is discharged onto the contact surface of the subsequent grate block. In particular, this can also lead to erosion of the air outlet openings arranged under the edge, which can negatively affect the controlled air supply to the combustion bed lying on the combustion grate.

In addition, the operator of an incineration plant is often not able to see with the naked eye when the grate block has exceeded its service life or how far the abrasion has progressed. In order to ensure safe operation of the plant, but nevertheless to avoid an unnecessary replacement of still functional grate blocks, a simple check of the degree of abrasion with the naked eye is therefore desirable.

It is therefore advantageous to provide a grate block as mentioned at the outset, which has a long service life and in which, in particular, the erosion of the wall section containing the air supply openings is minimized.

According to one aspect, the problem to be solved according to the invention is to provide a grate block as mentioned at the outset, which allows the degree of abrasion to be checked easily.

The object according to the aspect described above is achieved by the grate block defined in independent claim 1. Preferred embodiments of the grate block according to the invention are given in the claims dependent on the respective independent claims.

According to claim 1, the present invention thus relates to a grate block for a combustion grate in which successive grate blocks are arranged in steps one above the other and are designed in such a way that the material to be burned is shifted and conveyed by means of thrust movements performed relative to one another during combustion. As mentioned at the beginning, such combustion grates are also referred to as stepped grates.

The grate block according to the invention comprises a block body designed as a cast part. As a rule, the block body is designed essentially in the form of an elongate cuboid with a longitudinal axis L.

The block body comprises an upper wall, which forms a support surface that runs at least partially parallel to the longitudinal axis L of the block body, along which the material to be burned is to be conveyed and whose foremost end, viewed in the thrust direction S, forms an edge over which the support surface can be divided into one of a front wall formed thrust surface drops.

The front wall has at least one air supply opening, viewed in longitudinal section, at right angles or at an angle to the thrust surface, for supplying air to the combustion grate, and is designed in its lowermost region in the form of a foot, which is intended to rest on the bearing surface of an adjacent grate block in the thrust direction .

In the preferred embodiment, in which the grate block according to the invention is intended for a feed grate, the foot thus rests on the grate block that follows in the transport direction of the material to be burned, or on its contact surface. But it is also conceivable that the grate block according to the invention is intended for a reverse thrust grate; In this case, the foot rests on the preceding grate block or its contact surface in the direction of transport of the material to be burned.

At least the front bearing edge of the thrust surface is arranged in a plane E running essentially at right angles to the longitudinal axis L. In this regard, it is conceivable that a plane arranged in the lowest area of the front wall, the lower end of which is formed by the front bearing edge, is arranged in plane E, whereas it is also conceivable that only the line described by the front bearing edge is in plane E is arranged.

As a rule, the grate block is closed off laterally by a side wall that extends in the longitudinal direction. According to the invention, at least one side wall has a wear mark that describes a contour that is spaced apart from the plane of the support surface and/or from the plane of the thrust surface.

As will be described in detail below, the wear indicator allows the degree of wear to be determined very easily by eye. Thus, on the one hand It can be ensured that a worn grate block is detected in good time, which contributes to safer operation of the combustion grate. On the other hand, it enables the grate block to actually be used until the end of its lifetime; a replacement of a grate block that is actually still functional is thus prevented.

Because the original distance between the contour of the wear mark and the outer contour of the grate block is known, it is also possible to predict relatively reliably when the grate block will be worn out with constant operation.

The contour of the wear marking is preferably spaced from the plane of the contact surface and/or from the plane of the thrust surface by 15 mm to 30 mm, most preferably by 20 mm to 25 mm. This distance corresponds to the maximum permissible abrasion of the grate block up to which it is still fully functional.

It is further preferred that the contour of the wear marking runs parallel to the plane of the bearing surface and/or the thrust surface, at least in certain areas. This allows a particularly simple check of the degree of abrasion at the individual points on the grate block.

Particularly preferably, the contour of the wear marking runs parallel at least to that area of the bearing surface and the thrust surface where they meet. This is because the grate block is exposed to particularly high wear in this area and checking the degree of abrasion is therefore particularly relevant in this area.

It is also preferred that the wear mark is in the form of a notch or a recess. The notch or the recess can be continuous or interrupted. According to this embodiment, the additional material that is required for the preferred thickening of the wall in the area of the dropping edge can be at least partially compensated or even overcompensated by the material savings made possible by the notch or the recess. Since the notch or the recess is formed in the side wall and thus in an area of the grate block that is subjected to relatively little stress, this material saving is not at the expense of the stability or the service life of the grate block.

In addition, it is conceivable to provide an elevation or a profiling on the support surface of the grate block, which acts as a further wear mark. In this way, the abrasion can be determined very easily via the erosion of the elevation or the profiling. In particular, this additional wear mark can be provided with information about the grate block, which should be visible at least temporarily. For example, the further wear marking can be provided with the indication of origin or the "stamp" of the grate block manufacturer.

As mentioned, the present invention also relates to a grate block for a combustion grate of the type described above, which includes a block body designed as a cast part, which includes an upper wall that forms a support surface running parallel to a longitudinal axis L of the block body, along which the material to be burned is conveyed should be and viewed in the thrust direction S foremost end an edge for forms the material to be burned, over which the support surface drops into a thrust surface formed by a front wall.

The grate block is closed off on at least one side by a side wall extending in the longitudinal direction. According to the invention, it is characterized in that at least one side wall has a wear mark that describes a contour spaced apart from the plane of the support surface and/or from the plane of the thrust surface.

As mentioned, the presence of the wear mark allows the degree of wear to be determined very easily by eye. The grate block has generally reached the end of its service life when the outer contour of the grate block at least partially coincides with the contour of the wear mark or when the contour of the wear mark is no longer visible at all.

The grate block according to claim 1 can additionally in particular have an edge that is offset forward with respect to the plane E along the longitudinal axis L and viewed in the thrust direction S. Otherwise, the preferred features disclosed for the grate block according to the above embodiments are also preferred for the grate block according to claim 1.

According to a further aspect, the present invention also relates to a combustion grate comprising at least one of the grate blocks described above.

Furthermore, the present invention relates to the use of an above-described incineration grate for the incineration of waste and a Waste incineration plant comprising such a combustion grate.

Fig. 1

einen Rostblock gemäss dem Stand der Technik in der Seitenansicht;

Fig. 2

den in Fig. 1 gezeigten Rostblock des Stands der Technik in der Draufsicht von oben;

Fig. 3

den in Fig. 1 und 2 gezeigten Rostblock des Stands der Technik im Längsschnitt durch die Schnittebene A-A;

Fig. 4

einen Rostblock gemäss einer Ausgestaltung in der Seitenansicht;

Fig. 5

den Rostblock gemäss Fig. 4 in der Draufsicht von oben;

Fig. 6

den Rostblock gemäss den Fig. 4 und 5 im Längsschnitt durch die Schnittebene A-A;

Fig. 7

einen Rostblock gemäss der vorliegenden Erfindung in der Seitenansicht; und

Fig. 8

den Rostblock gemäss Fig. 7 in der Draufsicht von oben.

The invention is illustrated by the attached figures. Of these shows:

1

a grate block according to the prior art in side view;

2

the in 1 shown prior art grate block in plan view from above;

3

the in 1 and 2 shown grate block of the prior art in longitudinal section through the section plane AA;

4

a grate block according to an embodiment in side view;

figure 5

according to the grate block 4 in plan view from above;

6

the grate block according to the 4 and 5 in longitudinal section through section plane AA;

7

a grate block according to the present invention in side view; and

8

according to the grate block 7 in top view.

How from the Figures 4 to 6 compared to Figures 1 to 3 As can be seen, the grate block 10 has in common with previously known grate blocks that it comprises a block body 12 designed as a cast part, which in Substantially in the form of an elongated cuboid 121 with a longitudinal axis L is formed.

The block body 12 comprises an upper wall 14, which forms a support surface 16 running parallel to the longitudinal axis L, along which the material to be burned is to be conveyed and the front end of which, viewed in the thrust direction S, forms an edge 19, over which the support surface 16 can be shifted into one of a front Wall 20 formed thrust surface 22 drops. In the embodiments shown, the bearing surface has a first bearing surface area 16a and a second bearing surface area 16b, both of which run parallel to the longitudinal axis L, but the first bearing surface area 16a is offset upwards relative to the second bearing surface area 16b and is connected to it via a beveled transition 17 is.

Incidentally, in the in the Figures 1 to 3 In the embodiment of the prior art shown, the area of the bearing surface located immediately in front of the edge is designed in the form of a bevel 21 .

On the side opposite the front wall 20, the block body 12 has a rear wall 24 which is equipped with at least one hook 26 with which the grate block 10 can be hung in a block holding tube. A central web 29 is also arranged on the underside of the grate block 10 facing away from the support surface.

The grate block 10 is closed laterally by a side wall 28a, 28b extending in the longitudinal direction.

Within the combustion grate, the grate block 10 rests on a grate block that follows in the thrust direction S. For this purpose, the lowermost region 32 of the front wall 20 is designed in the form of a foot 34 which is intended to rest on the bearing surface of a grate block that is adjacent in the thrust direction S. The lowermost area, including the front bearing edge of the thrust surface formed therethrough, is arranged in a plane E running essentially at right angles to the longitudinal axis L.

As in 3 and 6 shown, in the previously known grate block and in the grate block specifically illustrated, two air supply openings 38 leading through the wall are formed in an upper region 36 of the front wall 20, i Air supply openings is shown.

In contrast to the grate block of the prior art, the grate block 10 is thickened in the area where the top wall 14 and the front wall 20 meet. Specifically, the wall thickening 40 is arched when viewed in longitudinal section.

The edge 19 formed by the thickened wall 40 is thus offset forwards along the longitudinal axis L and in the thrust direction S with respect to the plane E, with the distance D between the edge 19 and the plane E being approximately 25 mm in the embodiment shown.

In addition, the air supply openings are set back along the longitudinal axis L and viewed in the direction of thrust S with respect to the edge, in the specific embodiment shown by a distance d of approximately 8 mm.

in the in 6 In the grate block shown, the air supply openings 38, viewed in longitudinal section, extend at an angle α of approximately 90° to the thrust surface 22 in the area directly adjacent to the respective air supply opening.

According to the 7 and 8th In the grate block shown according to the invention, the side wall 28a has a wear marking 42 in the form of a recess 421, which describes a contour 44 spaced apart from the plane of the bearing surface 16, in particular the second bearing surface area 16b and the bevel 21, and from the plane of the thrust surface 22. The wear marking 42 or the contour 44 runs essentially parallel to the second contact surface area 16b and to the bevel 21 of the contact surface 16 and to the thrust surface 22. The contour 44 therefore runs parallel to the plane of the second contact surface area 16b in a first area 44a, in a second Area 44b parallel to the bevel 21, and in a third area 44c parallel to the thrust surface 22. Specifically, the wear mark in the embodiment shown is spaced from the plane E of the thrust surface 22 by a distance γ of about 20 mm.

In operation, the grate blocks 10 are moved relative to each other by means of the block support tubes. Depending on whether the block holding tubes are assigned to a stationary or a moving grate block, the block holding tubes are either attached to stationary brackets or to brackets that are arranged in a moving grate carriage. It is driven by hydraulic cylinders, which move the grate wagons back and forth on rollers on corresponding running surfaces.

The resulting relative movement causes the foot 34 of a first grate block 10 to be pushed forwards and backwards over the support surface 16 of the subsequent grate block 10, with the fuel being conveyed over the support surface 16 before it over the edge 19 onto the support surface 16 of the following grate block 10 is discarded.

The fact that the edge 19 is offset forwards with respect to the plane E, as described, means that at least part of the thrust surface 22 is exposed to reduced erosion by the material to be burned and, in particular, that the air can exit more easily through the air supply openings 38 . Moreover, due to the wall thickening 40 in that area of the grate block 10 which is exposed to particularly heavy wear, a significantly higher level of abrasion can be tolerated, with the result that an increased service life of the grate block is ultimately achieved.

The degree of abrasion can be determined using the wear mark in the 7 and 8th The embodiment shown can be determined very easily by eye: If the abrasion has reached such a level that the outer contour of the grate block 10 coincides at least partially with the contour 44 of the wear marking 42 in the side view or that the contour 44 of the wear marking 42 is no longer visible at all, then this is the case the grate block 10 is worn and must be replaced.

Because the original distance between the contour 44 of the wear mark 42 and the outer contour of the grate block 10 is known, it can also be predicted relatively reliably when the grate block will be worn out with constant operation.

Reference List

10

rust block

12; 121

block body; cuboid

14

top wall

16

bearing surface

16a, b

Areas of the support surface running parallel to the longitudinal axis

17

beveled transition

19

edge

20

front wall

21

bevel

22

thrust surface

23

front support edge

24

posterior wall of the block body

26

Hook

28a, b

side walls

29

center bar

30

block body interior

32

lowest part of the front wall

34

Foot

36

top of the front wall

38

air supply opening

40

wall thickening

42; 421

wear mark; return

44; 44a-c

Contour, different areas of the contour

L

longitudinal axis

S

thrust direction

i.e

Distance by which the air supply openings are set back with respect to the edge along the longitudinal axis L and viewed in the thrust direction S

E

Level in which the front support edge is arranged

D

Distance by which the edge is offset along the longitudinal axis L and viewed in the direction of shear S with respect to the plane E

a

Angle at which the air supply opening runs to the thrust surface, viewed in longitudinal section

g

Distance the wear mark is from the plane of the thrust surface

Claims (8)

1. A grate block (10) for a combustion grate in which sequential grate blocks are arranged one above the other in a step-like manner and are configured so as to rearrange and convey the combustion material during combustion by means of pushing movements which are carried out relative to each other, wherein the grate block (10) comprises a block member (12) which is formed as a cast component and which comprises an upper wall (14) forming a support face (16) that extends at least partially parallel with a longitudinal axis L of the block member and along which the combustion material is intended to be conveyed and a foremost end of the upper wall, when viewed in the pushing direction S, forms an edge (19) via which the support face (16) descends into a pushing face (22) formed by a front wall (20), and the grate block (10) is closed laterally each time by a side wall (28a, 28b) that extends in the longitudinal direction, characterized in that at least one side wall (28a, 28b) has a wear marking (42) which describes a contour (44) which is spaced apart from the plane of the support face (16) and/or from the plane of the pushing face (22).
2. The grate block as claimed in claim 1, characterized in that the contour (44) of the wear marking (42) is spaced apart from the plane of the support face (16) and/or from the plane of the pushing face (22) by from 15 mm to 30 mm and most preferably by from 20 mm to 25 mm.
3. The grate block as claimed in claim 1 or 2, characterized in that the contour (44) of the wear marking (42) extends at least partially parallel with the plane of the support face (16) and/or the plane of the pushing face (22).
4. The grate block as claimed in claim 3, characterized in that the contour (44) of the wear marking (42) extends parallel at least with the region of the support face (16) and the pushing face (22) where they meet each other.
5. The grate block as claimed in one of claims 1 to 4, characterized in that the wear marking (42) is constructed in the form of a continuous or interrupted notch or a recess (421).
6. A combustion grate comprising at least one grate block (10) as claimed in one of the preceding claims.
7. Use of a combustion grate as claimed in claim 6 for burning waste.
8. A waste combustion installation comprising a combustion grate as claimed in claim 6.

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