EP4273451A1 - A grate and a method for monitoring the grate - Google Patents

Abstract

The invention relates to a fire grate (1) for a waste incineration plant
- a drive unit (4),
- several rows of grate bars (2), each of which has a grate bar support (2a) on which several grate bars (2b) are rotatably mounted,
- a grate mechanism (3),
wherein the drive unit (4) is operatively connected to at least some of the rows of grate bars (2) via the grate mechanism (3) in such a way that a movement can be initiated in the grate bars (2b).

According to the invention, the grate mechanism (3) has at least one inclination sensor (5a, 5b) for determining and outputting inclination information (I), the inclination information (I) depending on an inclination (N) of the inclination sensor (5a, 5b). a reference direction (R) is formed

Description

The invention relates to a fire grate according to the preamble of the first claim, as well as a method for monitoring the fire grate. The invention can be used wherever fire grates are used, preferably in waste incineration plants.

Either moving grates or roller grates are used for grate firing in waste incineration plants. The fire grates known per se have a drive unit, a grate mechanism and rows of grate bars, whereby the rows of grate bars represent the components of the fire grate that are actually in contact with the material to be fired and the rows of grate bars are operatively connected to the drive unit via the grate mechanism in order to be able to drive the rows of grate bars and This allows the material to be fired to be transported and/or stoked in the usual way.

Part of the grate mechanism is formed, for example, by waves, in particular torsion waves, whereby the torsion waves in the case of push grates are designed to drive the grate bars of the push grate via grate bar supports, so that by twisting the torsion shafts, a lying material to be burned is transported and/or stoked during combustion can. However, other grate mechanisms for transmitting the drive movement are also possible.

In order to enable movement or twisting of the torsion shafts, various drive units can be provided, which are then operatively connected to the torsion shafts of the grate mechanism. The torsion shafts of a moving grate can, for example, be driven by hydraulic cylinders as a drive unit in order to increase the transport speed of the To be able to optimally adapt the firing material on the rows of grate bars to the locally different combustion conditions.

To monitor the functional activity of the fire grate, the advance of the fire grate is usually measured indirectly via displacement sensors on the drive unit itself, for example on the hydraulic cylinder. If the drive unit fails, you can react accordingly. However, if a component behind the drive unit fails, in particular a component of the grate mechanism, the drive unit continues to work unaffected, while the rows of grate bars themselves stand still or do not move as expected and the fire grate is therefore not actually advanced. Such a failure of the rust mechanism is therefore usually not detectable.

Additionally is in CN 1 12 577 057 A Furthermore, it is described to install cable pull or tear-off transmitters in order to detect a change in length due to movement of the grate bars. In GB 1 223 668 A It is also intended to monitor the movement of the drive unit via limit switches or limit switches. However, there is no provision for monitoring the rust mechanics. In US 2015 / 0 000 573 A1 It is described how to thermally monitor the firing material via a camera. In US 2020 / 0 182 462 A1 A fire grate with a grate mechanism and contactless sensors is also described.

It is the object of the invention to enable reliable monitoring of the fire grate, in particular the actual advance of the fire grate.

This object is achieved by a fire grate according to the features of claim 1 and by a method according to claim 7. The subclaims reflect advantageous embodiments of the invention.

Accordingly, a fire grate is provided for a waste incineration plant, which has a drive unit, preferably a hydraulic unit, in particular with a hydraulic cylinder, rows of grate bars, each of which has a grate bar support on which several grate bars are rotatably mounted, and a grate mechanism which is in the direction of force or direction of action the drive unit connects, wherein the drive unit is operatively connected to at least some of the rows of grate bars via the grate mechanism in such a way that a movement can be initiated in the grate bars in order to transport and / or stoke a lying material to be fired. Preferably not every row of grate bars is driven, but rather, for example, only every second row of grate bars and the rows of grate bars in between are non-driven rows of grate bars.

According to the invention, it is provided that the grate mechanism has at least one inclination sensor for determining and outputting inclination information, the inclination information being formed depending on an inclination of the inclination sensor relative to a reference direction, so that the inclination information results in a position of at least the respective component of the grate mechanism which the at least one inclination sensor is arranged can be determined.

An active connection is understood to mean any type of mechanical connection that is suitable for transmitting a movement between the drive unit and the driven rows of grate bars. An active connection therefore enables a flow of force from the drive unit to the respective rows of grate bars.

Based on the inclination information, which is detected by the inclination sensor on the respective component of the grate mechanism, a movement of the grate mechanism can then be determined, so that it is also possible to draw conclusions about the movement of the rows of grate bars. This allows A method according to the invention for monitoring the fire grate can also be carried out, for example by transferring the inclination information detected by the at least one inclination sensor to a control device in the waste incineration plant. This can then process the tilt information accordingly and react to it.

Compared to the prior art, the advantage is already achieved that the movement of the fire grate during its operation is not monitored by looking at the movement of the drive unit, i.e. the starting point of the movement, but rather by looking at the movement in the direction of force flow further forward on the Rust mechanics. If one of the components of the grate mechanism fails due to a defect, this can be determined immediately, with the at least one inclination sensor preferably being arranged on at least one component of the grate mechanism, which is selected from the group consisting of: torsion shaft, bolt, preferably collar bolt, coupling rod , bearings, torsion levers.

In particular, the inclination sensor is attached to a component of the grate mechanism, in whose further force flow or further active connection to the rows of grate bars there are no or only a few other highly loaded connections that could fail. This guarantees that if a component of the grate mechanism fails along the power flow or the chain of effects from the drive unit to the rows of grate bars, this can be detected via the inclination sensor.

Preferably, it is provided that the torsion shaft of the grate mechanism runs parallel to the rows of grate bars and interacts with the grate bar supports via an upper torsion lever and with the drive unit via a lower torsion lever,
wherein the at least one inclination sensor for determining and outputting the inclination information on at least one end face of the torsion shaft and/or is arranged on the upper torsion lever and/or on the lower torsion lever. Inclination information, which is determined by an inclination sensor on at least one of the end faces of the torsion shaft or on the respective torsion lever, enables reliable information about the movement of the grate mechanism at one of the above-mentioned "rear" positions of the chain of action and thus with a high degree of certainty about the movement the rows of grate bars and ultimately the actual advance of the fire grate. This means that a more reliable statement can be made about the actual advance of the fire grate.

Preferably, it is additionally provided that an inclination sensor is arranged on the opposite end faces of the torsion shaft and / or on torsion levers that are opposite on each side (of the fire grate) or that other components of the grate mechanism are on opposite sides (of the fire grate). This also makes side-specific and/or redundant monitoring of the movement of the grate mechanism possible in order to obtain further conclusions about the operation of the fire grate, for example a side-specific mechanical load.

By monitoring the fire grate according to the invention, in the simplest case, a functional check of an above-mentioned fire grate according to the invention is possible, with an error or an impairment of the grate mechanics and thus the fire grate being detected and output, for example accompanied by an error message if the at least one inclination sensor The inclination recorded and output via the inclination information during operation of the drive unit differs from the target inclination that is to be expected during operation of the fire grate. What is equivalent to this is that the inclination output via the inclination information does not change (dN=0, N=constant), although this does happen during operation of the fire grate, in which the rows of grate bars actually move should (NSoll =/= 0, N=changing), is to be expected. This simply indicates damage to the rust mechanism. But even if the grate mechanism's ability to move is reduced or otherwise impaired, movement that deviates from the target inclination can occur, which can indicate a fault or impairment.

In addition, it is to be expected that repeated, consistent actuation of the drive unit with an intact fire grate or grate mechanism will always produce the same inclination information or inclinations in the inclination sensor. As soon as the inclination information or inclination deviates from this same, repeating inclination information, there is a change or impairment in the drive unit or at least the grate mechanism, which can indicate a malfunction of the same.

This makes it possible to check the function of the drive unit and grate mechanics of a fire grate during operation, which reduces downtimes.

In the method according to the invention, a side-by-side comparison of the determined inclinations and/or inclination information from different inclination sensors can also be carried out using several inclination sensors, in particular with two inclination sensors arranged on opposite end faces of the torsion shaft or other components of the grate mechanism, by determining a torsion difference by comparing inclinations and/or from changes in inclination of inclination sensors on opposite sides of the grate mechanism, in particular on opposite end faces of the torsion shaft of the grate mechanism, and from the torsion difference it is derived whether the fire grate is mechanically loaded evenly or on one side.

It is assumed that the torsion difference represents a measure of the twisting of the torsion shaft along its longitudinal axis or, in the case of other components of the grate mechanics, a measure of a sideways difference in the inclinations.

If the fire grate is evenly loaded, there is a certain twist along the longitudinal axis of the torsion shaft due to the drive movement initiated on one side, which corresponds to a side-to-side difference in the inclinations of the inclination sensors and can be detected by appropriate evaluation of the inclination information. This specific torsion under uniform load can preferably also be referred to as the reference torsion difference. The reference torsion difference can also be selected for a different load.

If the fire grate is loaded unevenly, the torsion difference detected by the inclination sensors then deviates from this reference torsion difference. With an increased load on the side of the fire grate facing the drive initiation, the torsion difference decreases compared to the reference torsion difference, while it increases with an increased load on the side of the fire grate facing away from the drive initiation.

In this simple way, it is possible to conclude that there is a uniform or one-sided mechanical load on the fire grate using the inclination sensors.

The invention will be explained in more detail below using an exemplary embodiment and two figures.

Fig. 1

Ein Ausführungsform eines Feuerrosts einer Müllverbrennungsanlage in einer ersten Stellung;

Fig. 2

das Feuerrost aus Fig. 1 in einer zweiten Stellung.

The figures show:

Fig. 1

An embodiment of a fire grate of a waste incineration plant in a first position;

Fig. 2

the fire grate Fig. 1 in a second position.

The Figure 1 shows a fire grate 1 in the form of a moving grate with a drive unit 4, a grate mechanism 3 and rows of grate bars 2 made up of several grate bars 2b mounted on grate bar supports 2a in a first position. The grate bars 2b of adjacent rows of grate bars 2 lie on top of each other like roof tiles. The drive unit 4 is operatively connected to the rows of grate bars 2 via the grate mechanism 3, the drive unit 4 being formed in the present case by a hydraulic cylinder 8. However, other types of drives with the same effect are also possible.

The grate mechanism 3 transmits the initial movement of the drive unit 4 by means of a bolt 9, for example a collar bolt, a coupling rod 7, a lower torsion lever 11a, a bearing 10, a torsion shaft 6 and an upper torsion lever 11b to the grate bar supports 2a of the respective grate bar rows 2. Through this Drive movement and the roof tile-like lying on top of each other of adjacent rows of grate bars 2 can, as is well known, cause a feed and stoking for the material to be fired (not shown) located on the rows of grate bars.

At the in Fig. 1 A first inclination sensor 5a is attached to the visible first end face 6a of the torsion shaft 6. On the opposite, in Fig. 1 A second inclination sensor 5b is also attached to the invisible second end face 6b of the torsion shaft 6. In a simple embodiment, only one of the two inclination sensors 5a, 5b can be provided.

Each inclination sensor 5a, 5b measures an inclination N of the inclination sensor 5a, 5b relative to a reference direction R and generates inclination information I corresponding to the inclination N, which can be output via an inclination signal Sa, Sb. Since when the torsion shaft 6 is rotated, the inclination N of the inclination sensors 5a, 5b on the respective end face 6a, 6b changes relative to the reference direction R, the inclination information I correlates with a rotational position of the torsion shaft 6.

In the in Fig. 1 In the first position of the fire grate 1 shown, the inclination sensors 5a, 5b measure, for example, a first inclination N1 of 0°, if it is assumed that the inclination sensors 5a, 5b are aligned in the reference direction R in this rotational position of the torsion shaft 6. Accordingly, this first inclination N1 can then be output via the inclination information I. The hydraulic cylinder 8 of the drive unit 4 is retracted at this first inclination N1.

Figure 2 shows the fire grate 1 Fig. 1 in a second position, the same parts being provided with the same reference numerals. In the second position of the fire grate 1, the hydraulic cylinder 8 is fully extended, which means that the position of the rows of grate bars 2 also changes due to the described operative connection via the grate mechanism 3. So by repeatedly changing from the first ( Fig. 1 ) to the second position ( Fig. 2 ) For example, a feed and stoking for the material to be fired (not shown) located on the rows of grate bars 2 can be achieved.

The inclination sensors 5a, 5b attached to the end faces 6a, 6b of the torsion shaft 6 measure in the in Fig. 2 shown second position of the fire grate 1 a second inclination N2 of, for example, approximately -30 ° relative to the reference direction R, which can be output accordingly as inclination information I. Between the fully extended position ( Fig. 2 ) and the fully retracted position ( Fig. 1 ) of the hydraulic cylinder 8 can Correspondingly, further inclinations N are detected by the inclination sensors 5a, 5b and corresponding inclination information I is output via the respective inclination signal Sa, Sb. In this way, each position of the drive unit 4 or the hydraulic cylinder 8 can be assigned a specific inclination N or a specific inclination information I.

The inclination information I determined by the inclination sensors 5a, 5b can be transmitted via the inclination signals Sa, Sb to a control device 20 in a control center of the waste incineration plant. The fire grate 1 can thus be monitored during operation, in particular for its functionality. If the components of the drive unit 4 and the grate mechanism 3 are functioning, the first position is repeated ( Fig. 1 ) and second position ( Fig. 2 ) periodic, meaning periodically recurring slopes N; N1, N2 or inclination information I, which is detected with the inclination sensors 5a, 5b.

However, if, for example, the coupling rod 7 breaks due to excessive mechanical stress or fatigue or the bearings 10 tilt, the periodically recurring target inclinations NSoll are no longer produced as expected by means of the inclination sensors 5a, 5b and are output via the inclination information I, since then the The rotational position of the torsion shaft 6 no longer changed as expected. It can therefore be concluded that there is an error in the drive unit 4 and/or the grate mechanism 3 if the inclination information I no longer transmits the expected target inclination NSoll.

Compared to the state of the art, this has the advantage that monitoring of the movement takes place further back in the chain of effects. If, for example, it is determined that the hydraulic cylinder 8 is still deflected, but the torsion shaft 6 is no longer rotating, according to the Invention can be concluded that there is a mechanical impairment between these two components.

For this described functional check of a fire grate 1, one of the inclination sensors 5a, 5b is sufficient. In principle, this can then also be attached at other locations than on one of the end faces 6a, 6b of the torsion shaft 6, for example on another component of the grate mechanism 3, for example on the bolt 9, on the lower torsion lever 11b or the upper torsion lever 11a. A prerequisite for the positioning of the inclination sensor(s) 5a, 5b is that a change in the inclination N or the inclination information I is caused at this position when the drive unit 4 is actuated.

Furthermore, it should be noted that the position is selected such that the respective inclination sensor 5a, 5b is not subjected to excessive thermal stress. Even if the inclination sensor 5a, 5b is in the downwind, the thermal load becomes higher the closer the inclination sensor 5a, 5b is to the material to be fired located on the rows of grate bars 2. Therefore, if possible, the inclination sensors 5a, 5b should not be attached to the grate mechanism 3 above the torsion shaft 6 or only just above it in order to ensure long-term, error-free operation when monitoring the fire grate 1.

With the one in the Figures 1 and 2 In the embodiment shown with two inclination sensors 5a, 5b, which are attached to opposite end faces 6a, 6b of the torsion shaft 6, it is also possible to monitor mechanical loading of the fire grate 1 for irregularities as follows:
If the material to be fired is transported unevenly from side to side over the rows of grate bars 2, that is, for example, on the side of the rows of grate bars 2 facing away from the drive unit 4, there is a particularly large amount of material to be burned compared to the side above the drive unit 4, this also leads to one during operation of the fire grate 1 sideways unevenly strong mechanical load on the torsion shaft 6, which then twists.

This twisting of the torsion shaft 6 is noticeable in that the end faces 6a, 6b of the torsion shaft 6 are in different rotational positions and / or the rotational positions are in operation of the fire grate 1 with the drive acting on one side (via the drive that only acts on the torsion shaft 6 on one side Change the coupling rod 7) to different extents. This can be detected via the inclination sensors 5a, 5b arranged on the opposite end faces 6a, 6b of the torsion shaft 6 if the inclination information I is recorded on an individual side and compared with one another.

• Bestimmen einer Torsionsdifferenz D durch Vergleichen der über die Neigungsinformationen I übertragenen Neigungen N, die von den an gegenüberliegenden Stirnseiten 6a, 6b der Torsionswelle 6 angeordneten Neigungssensoren 5a, 5b gemessen werden, und/oder der daraus folgenden Neigungs-Änderungen dN,
• Ableiten, in Abhängigkeit der Torsionsdifferenz D, ob das Feuerrost 1 gleichmäßig oder ungleichmäßig, insbesondere einseitig mechanisch belastet wird.

For functional monitoring, the following steps can be carried out, for example:

• Determining a torsion difference D by comparing the inclinations N transmitted via the inclination information I, which are measured by the inclination sensors 5a, 5b arranged on opposite end faces 6a, 6b of the torsion shaft 6, and / or the resulting inclination changes dN,
• Deduce, depending on the torsion difference D, whether the fire grate 1 is mechanically loaded evenly or unevenly, in particular on one side.

The transmitted inclination information I therefore results in a difference between the inclinations N on the two end faces 6a, 6b the torsion shaft 6 and/or a difference between a change in inclination dN on the two end faces 6a, 6b of the torsion shaft 6, the respective difference can be output as a torsion difference D. The torsion difference D can then be viewed as a measure of an uneven mechanical load on the torsion shaft 6 and thus an uneven transport of firing material over the fire grate 1.

As in Figures 1 and 2 shown, the initiation of the drive movement into the torsion shaft 6 takes place on one side, namely in the area of the second end face 6b of the torsion shaft 6. If the fire grate 1 is evenly loaded, there is a bed of garbage distributed homogeneously over the entire fire grate 1. Due to the drive movement being initiated only on one side, the torsion shaft 6 has a torsion difference D along its longitudinal course. The torsion difference D in the case of a uniform load on the fire grate 1 is hereinafter referred to as the reference torsion difference RD. The value of the torsion difference D can be calculated from the difference of the inclination N1 of the first inclination sensor 6a and the inclination N2 of the second inclination sensor 5b, the inclination sensors 5a, 5b being attached to the end faces 6a, 6b of the torsion shaft 6. The reference torsion difference RD with uniform loading of the fire grate 1 is, for example, 1.2°.

If a particularly large amount of firing material comes to lie on the side of the fire grate 1 above the first end face 6a of the torsion shaft 6, i.e. on the side facing away from the drive initiation, the torsion difference D increases compared to the reference torsion difference RD, for example to 2.1 °. If there is a particularly large amount of fuel on the fire grate 1 above the second end face 6b of the torsion shaft, i.e. on the side facing the drive initiation, the torsion difference D is reduced compared to the reference torsion difference RD, for example to 0.3°. This can be done using: the deviation of the torsion difference D from the reference torsion difference RD determined by means of the inclination sensors 5a, 5b makes a statement about the mechanical load on the fire grate 1.

So that different overall loads can also be taken into account, for example with different garbage bed heights, the oil pressure in the hydraulic unit 8 can be taken into account and the reference torsion difference RD can be automatically calculated accordingly.

If, for example, a one-sided mechanical load on the fire grate 1 is determined using the method described above, countermeasures can be taken to prevent the fire grate 1 from being overloaded.

Reference symbol list

1

fire grate

2

Row of rust bars

2a

Grate bar carrier

2 B

rust bar

3

Rust mechanics

4

Drive unit

5a, 5b

first/second inclination sensor

6

Torsion shaft

6a

first end face of the torsion shaft 6

6b

second end face of the torsion shaft 6

7

Coupling rod

8th

Hydraulic unit

9

bolt

10

camp

11a

upper torsion lever

11b

lower torsion lever

20

Control device

D

Torsion difference

RD

Reference torsion difference

I

Tilt information

N

Tilt

N1

first inclination

N2

second inclination

Ntarget

Target inclination

dN

Tilt change

R

Reference direction

Sat, Sb

first/second tilt signal

Claims (11)

Fire grate (1) for a waste incineration plant, comprising - a drive unit (4), - several rows of grate bars (2), each of which has a grate bar support (2a) on which several grate bars (2b) are rotatably mounted, - a grate mechanism (3), wherein the drive unit (4) is operatively connected to at least some of the rows of grate bars (2) via the grate mechanism (3) in such a way that a movement can be initiated in the grate bars (2b), characterized in that the grate mechanism (3) has at least one inclination sensor (5a, 5b) for determining and outputting inclination information (I), the inclination information (I) depending on an inclination (N) of the inclination sensor (5a, 5b) relative to a reference direction (R) is formed. Fire grate (1) according to claim 1, characterized in that the at least one inclination sensor (5a, 5b) is arranged on at least one component of the grate mechanism (3), which is selected from the group consisting of: torsion shaft (6), bolt (9 ), preferably collar bolts, coupling rod (7), bearing (10), torsion lever (11a, 11b). Fire grate (1) according to claim 2, characterized in that the torsion shaft (6) of the grate mechanism (3) runs parallel to the rows of grate bars (2) and has an upper torsion lever (11a) with the grate bar supports (2a) and a lower torsion lever ( 11b) interacts with the drive unit (4),
wherein the at least one inclination sensor (5a, 5b) for determining and outputting the inclination information (I) on an end face (6a, 6b) the torsion shaft (6) and/or on the upper torsion lever (11a) and/or on the lower torsion lever (11b). Fire grate (1) according to claim 3, characterized in that an inclination sensor (5a, 5b) is arranged on the opposite end faces (6a, 6b) of the torsion shaft (6). Fire grate (1) according to one of the preceding claims, characterized in that the inclination information (I) detected by the at least one inclination sensor (5a, 5b) can be transmitted to a control device (20) in the waste incineration plant. Fire grate (1) according to one of the preceding claims, characterized in that the drive unit (4) has a hydraulic unit (8), preferably a hydraulic cylinder. Method for monitoring a fire grate (1) according to one of the preceding claims during an actuation of the drive unit (4) of the fire grate (1), with at least the following steps: - Reading and processing the inclination information (I) of the at least one inclination sensor (5a, 5b), - Determining the inclination (N) of the at least one inclination sensor (5a, 5b) arranged on the grate mechanism (3) relative to the reference direction (R), and - Comparing the determined inclination (N) of the at least one inclination sensor (5a, 5b) with a target inclination (NSoll), which results from a changed position of the drive unit (4), and/or comparing inclinations (N) and/or Inclination information (I) from different inclination sensors (5a, 5b). Method according to claim 7, characterized in that an error or an impairment of the grate mechanism (3) is recognized and output when the inclination (N) detected by the at least one inclination sensor (5a, 5b) and output via the inclination information (I) changes. differs from the target inclination (NSoll) during operation of the drive unit (4). Method according to claim 7 or 8, characterized in that the following steps are carried out to compare inclinations (N) and/or inclination information (I) from different inclination sensors (5a, 5b): - Determining a torsion difference (D) by comparing inclinations (N) and/or changes in inclination (dN) of inclination sensors (5a, 5b) on opposite sides of the grate mechanism (3), in particular on opposite end faces (6a, 6b). Torsion shaft (6) of the grate mechanism (3), - Deduce from the torsion difference (D) whether the fire grate (1) is subjected to mechanical stress evenly or on one side. Method according to claim 9, characterized in that the torsion difference (D) is derived from a difference between the inclinations (N) of inclination sensors (5a, 5b) on opposite sides of the grate mechanism (3), in particular on the two end faces (6a, 6b). Torsion shaft (6), and/or from a difference between a change in inclination (dN) of inclination sensors (5a, 5b) on opposite sides of the grate mechanism (3), in particular on the two end faces (6a, 6b) of the torsion shaft (6) , is formed. Method according to claim 9 or 10, characterized in that the derivation from the torsion difference (D) as to whether the fire grate (1) is mechanically loaded uniformly or on one side is carried out by the torsion difference (D) is compared with a reference torsion difference (RD), the reference torsion difference (RD) indicating, for example, the torsion difference (D) that exists when the fire grate (1) is evenly loaded.

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