DE102017101226A1 - Device for sealing between windboxes of different pressure in traveling grate systems - Google Patents

Abstract

The present invention relates to a device for the thermal treatment of bulk material, comprising a traveling in the direction of travel traveling grate chain consisting of an endless traveling grate (1) with movable members and a plurality of grate carriage (3). The grate carriages (3) each consist of a frame (30) with end pieces (33) to which impellers (31) are fastened, and grate bars (35) arranged on cross members (32). Furthermore, the device has wind boxes (41, 43) which are arranged such that gas flows from at least one wind box (41, 43) through the grate carriages (3) and their grate bars (35) out of or into the wind boxes. At least one prestressed profile (50, 51) during operation is provided, which is arranged so that a component (50) in regular operation is in contact with two transverse members (32) in at least one position of the traveling grate (1).

Description

The invention relates to a device for the thermal treatment of bulk material, comprising a circulating in the direction of travel traveling grate chain, consisting of an endless traveling grate with movable grate carriage, each consisting of a frame with cross members and end pieces and arranged on cross bars grate bars and at least two wind boxes arranged so are that gas flows through the grate formed from the grate bars from or into the at least two wind boxes. The invention also relates to a process for the thermal treatment of bulk material in this plant.

In pellet burning or sintering machines, the bulk material to be treated, for example iron ore, iron oxides or zinc ore, is applied to grate carriages. These grate carriages consist of a frame equipped with wheels and consisting of end pieces and cross members and arranged between the cross bars grate bars. A variety of such rust truck forms an endless rust truck chain, which is also referred to as a traveling grate.

1. 1. die Beschickungszone,
2. 2. die erste Trocknungszone,
3. 3. die zweite Trocknungszone,
4. 4. die Vorbrennzone,
5. 5. die Brennzone,
6. 6. die Nachbrennzone,
7. 7. die Kühlzone und
8. 8. die Austrittszone.

In 1 For example, a pellet burning machine 1 for burning iron ore pellets to which the present invention is applied is shown. The bulk material is abandoned at a feed station in front of a hood 2 on rust truck 3, which form a designated as traveling grate 4 endless grate car chain. Under the hood 2, the bulk material transported on the grate carriage 3 passes through a plurality of thermal treatment stations. Specifically, the stations are at

1. 1. the feeding zone,
2. 2. the first drying zone,
3. 3. the second drying zone,
4. 4. the pre-firing zone,
5. 5. the burning zone,
6. 6. the afterburning zone,
7. 7. the cooling zone and
8. 8. the exit zone.

In these zones, the grate trucks are loaded with the material, the bulk material is dried, preheated, fired and then cooled again. The traveling grate is guided at the treatment stations under the hood 2 on an upper strand 5 of a continuous conveyor 6, wherein the rollers 7 of the grate carriage 3 are guided between an inner rail guide 8 and an outer rail guide 9. The drive of the traveling grate 4 via a drive or lifting wheel 10, which is designed as a gear and engages with its tooth gaps (recesses 11) on the rollers 7 of the grate carriage 3.

After passing through the hood 2, the grate carriage 3 of the traveling grate 4 reach a discharge station which is associated with a lowering or driven wheel 13 of the continuous conveyor 6. At the lowering wheel 13, as with the lifting wheel 10, tooth spaces 14 of the output gear wheel engage the rollers 7 of the grate carriages 3. The grate carriage 3 are tilted so that their load is dropped by gravity. Since the grate carriage 3 are guided by the outer rail guide 9, they themselves do not fall down, but are returned in a lower strand 15 of the continuous conveyor 6 upside down to the lifting wheel 10. Below the hood 2 wind boxes 16 are arranged, which allow a controlled gas flow. The grate carriages 3 move in the region of the upper run 5 between the upper hood 2 and the lower wind boxes 16, without them colliding with the components of the hood 2 or the wind boxes 16.

In normal operation, the traveling grate 4 runs endlessly on the continuous conveyor 6 and transports the bulk material to be treated through the treatment stations under the hood 2, before it is dropped at the discharge station and further processed in no longer designated manner.

As already mentioned, in the two drying zones, the pre-combustion zone, the burning zone, the afterburning zone and the cooling zone, the bulk material contained in the grate carriage is thermally treated by hot or cold gas either from the windbox through the bed in the grate carriage into the hood or out the hood flows through the bed in the grate carriage into the windbox. There is no flow in the feed zone and the exit zone. Therefore, there is a change of the vectorially directed flow between the feed zone and the first drying zone with upward flow, since here there is a change between no flow and flow from the wind box through the bed into the hood. For this purpose, the wind box associated with the first drying zone has an overpressure. The second change in the flow direction is between the first and second drying zone, since in the second drying zone gas from the hood is drawn through the bed in the windbox by the windbox has a negative pressure in this zone. Finally, there is a renewed flow direction change between the afterburning zone and the cooling zone after the pre-firing zone, firing zone and afterburning zone have all continued to be flown with a flow directed into the windboxes from the hood, caused by Negative pressure in the respective wind boxes. The cooling is in turn flowed from the windbox into the hood, caused by overpressure in the windboxes associated with the cooling. Another difference in flow is found between the cooling zone and outlet zone, since the latter is not flowed through at all.

Since these flow direction changes are each caused by different pressures in the associated windboxes and these windboxes are immediately adjacent to each other, it is important to seal the transition between the adjacent windboxes in order to avoid unwanted gas flows directly from the higher pressure windbox comes in the windbox with the lower pressure. Such unwanted gas flows lead in the best case only to increased power consumption of the connected fan, because an additional volume flow must be promoted. In many cases, however, the unwanted gas flow additionally results in partial pressure equalization between the adjacent windboxes, so that the pressure in the windbox decreases with the higher pressure, whereas the pressure in the windbox increases with the lower pressure. This in turn has the consequence that the velocity of the flow through the bed on the grate carriage decreases, with the result that the thermal treatment in the respective zone does not reach the desired level. In any form hereby suffers the efficiency of the thermal treatment. The sealing task is made more difficult by the fact that the grate carriages are to move unhindered from one zone to the next zone.

Usually, therefore, working with sealing flaps, which are located between the two wind boxes with different pressures and which are pressed by means of a lever and weight system to the underside of the passing grate carriages. In their extent such sealing flaps are designed so that they seal the two wind boxes from each other when applied to the grate carriage both in terms of their length and in terms of their width. The problem with such sealing flaps are, above all, two aspects. On the one hand, in the case of incidents, the grate carriages must also be moved counter to the usual direction of movement. In this case, the edge of a grate carriage can hit the edge of the sealing flap and wedge with it so that the sealing flap and / or the grate carriage take permanent damage. On the other hand, the grate trucks have the property to plastically deform during operation. This means that the cross member bend due to the weight load with the bulk of the bulk material in conjunction with the elevated temperatures of the cross member in the direction of the wind boxes U-shaped. With such a deflection, only the lowest point of the curve indicated by the cross member rests on the sealing flap, whereas in the remaining region of the grate frame, there is no longer any contact with the sealing flap and thus there is no longer a seal. In addition, it is customary to turn over the cross member of the grate carriage after a certain period of operation, so that the cross member then extend arcuately over the sealing flap and also no sealing effect is present.

Furthermore, it should be noted in a constellation in which the first passed windbox overpressure and the downstream windbox negative pressure, that these pressure conditions can cause the movably mounted sealing flap on the lever, despite the weight no longer completely closes.

All this leads to the fact that no reliable sealing performance is required and, on the contrary, serious damage can occur in the grate carriage chain and on the sealing flaps when the movement is opposite to the direction of movement that is normal during operation.

It is therefore an object of the present invention to provide a seal assembly for the windboxes in a plant for the thermal treatment of bulk materials, which ensures a seal even when pressure differences between the two wind boxes and on the other also in deformations of the grate carrier crossbars. Furthermore, this seal should be such that a movement of the grid carriage chain against the usual direction of movement is possible without causing damage in the rust truck chain or other components.

This object is achieved with a system having the feature of claim 1.

The device according to the invention comprises a moving in the direction of travel traveling rust chain, which consists of an endless traveling grate with movable members. Furthermore, it includes the grate carriages, each consisting of a frame with wheels and arranged on cross beams grate bars. Furthermore, the system includes at least two windboxes arranged one behind the other in the direction of movement, which are arranged so that gas can flow through the grate carriages out of or into at least one of the windboxes.

According to the invention, a component, as a rule a profile, but it can also be a plate provided, which is arranged so that it is biased in regular operation in at least one position of the traveling grate, for this purpose in contact with two cross members stands. The profile can thus, for example, as a leaf spring be understood, which establishes the contact. Here the profile is at the same time the prestressed component as well as the sealing component. Likewise, these tasks may also be distributed so that one profile is the prestressed component while the seal is made via a second sealing member such as a plate.

Contact within the meaning of the invention means that the component directly touches the grate carriage, preferably the one or more cross member of the grate carriage. This contact between the tread and the grate trolley results in the undesirable gas flow from the higher pressure windbox being significantly reduced to the lower pressure windbox.

The embodiment of the invention has the advantage that even with deformation of the grate, as they are unavoidable in view of the high temperatures and mechanical loads during operation, the profile itself readjusted due to its bias and thus preserves the sealing effect. In addition, a mobility of the sealing plate is given, so that the risk of wedging with the grate carriage is greatly reduced in a movement contrary to the usual direction of movement of the traveling grate.

It is particularly preferred if the profile is prestressed in contact with an undeformed grate carriage cross member having a maximum bending stress which is between 50 and 70% of the yield strength of the material used for the profile. This allows a sufficiently large range of elastic deformations of the profile to ensure a sufficient sealing effect even with differently shaped grate carriage cross members while reliably avoid plastic deformation of the profile. To be particularly favorable, it has been found that the geometry of the profile is chosen so that the maximum bending stress in the profile at maximum downwardly bent grate carriage cross member between 60 and 80% of the yield strength and at maximum upwardly bowed grate cross member between 40 and 60% of the yield strength.

Furthermore, it has proven to be advantageous if the profile in the relaxed or non-prestressed state, that is without contact with at least one grate carriage, a horizontal or arcuate plate which is in direct contact with the two grate carriages in at least one position of the traveling grate , In the simplest case, so that the profile as a spring leaf, for example. As a parabolic spring, wave spring, elliptical (three-quarter elliptic, Halbelliptikfeder, Viertelelliptikfeder) is formed. The dimensioning is such that the profile is in direct contact with two grate carriages even in at least one position of the traveling grate during operation, thus resulting in a seal. Due to the bias of the profile and its simultaneous action as a sealing element further interfaces, which represent additional weak points in the system due to the high thermal load can be avoided.

In the case of an arcuate design of the profile in the relaxed state, the rounding extends in the direction of movement of the traveling grate. The concave shape results from the fact that it is either rounded to a central part or has permanently adopted this form by a prior bias. This design has the advantage that a snagging of the grate carriage when passing the profile without prior contact of the grate carriage to the plate emerges less easily than in a relaxed state horizontally extending plate.

As another alternative, it is possible to form the profile with a center part which preferably extends horizontally in the relaxed state, which preferably extends parallel to the direction of movement of the traveling grate and on which at least one region branching in the direction of movement is provided. This area has an angle between 1 and 179 °.

Particularly favorable in this variant is a trapezoidal shape in the relaxed state based on a cross section parallel to the direction of movement of the traveling grate. The trapezoidal shape has the advantage that the sealing plate is not displaced by the parallel arrangement of the central part even with a movement against the direction of movement of the traveling grate, as the grate carriages are moved under the same conditions in both directions by the bevelled area on the two, opposite sides can, namely in the usual direction of movement and in the opposite direction of movement. The angles of the two, opposing area may be the same or different, but are in any case between 1 and 179 °

In a trapezoidal configuration, the prestressed profile and / or the sealing plate has a horizontal base surface and one of them branching off at an angle α in the direction of movement of the traveling grate, at least one side surface, preferably two opposing side surfaces. The angle α between the side surface and the base surface is favorably between 130 and 170 °. This ensures that there is no entanglement during movement of the traveling grate. Particularly preferred is a design of two opposing side surfaces whose angle α may be the same or different, but in any case in the range of 130 to 170 °, as well as a movement against the usual direction of movement snagging the grate carriage can be prevented with the sealing plate.

It is particularly advantageous if the profile which is trapezoidal in the relaxed state deforms concavely in the pretensioned state during operation of the traveling grate.

It is also advantageous if at least two profiles are arranged one above the other and are held together by a heart pin and / or a spring clip. As a result, the permanent elasticity of the device can be increased.

In this context, it has proven to be extremely advantageous if between at least two profiles lubrication and / or plastic, for example in the form of a film or plastic plates, are provided. Thus, abrasion between the two profiles, and thereby increased material wear, avoided or reduced.

As low, it has further been found, if the at least one profile is biased by at least one further L- or C-shaped elastic profile or by two more C-shaped elastic profiles. For this purpose, these other profiles are arranged opposite the traveling grate chain and press the first profile from below, preferably orthogonal to the direction of movement of the traveling grate chain against the grate carriages. The other profiles described are particularly simple and therefore low-maintenance components.

It is also beneficial if the strength of the first profile decreases towards the two opposite sides arranged in the direction of movement of the traveling grate. As a result, the profile is reinforced at the point of increased material stress by the bias.

The dimensioning of the prestressed profile itself or of the sealing plate preferably takes place in such a way that in the regular operation of the traveling grate there are always two grate carriage cross members in contact with the sealing plate. For this purpose, the extent of the contacting part, ie the prestressed profile itself or an applied plate, in the x-direction is chosen so that it corresponds to at least the largest occurring in the entire traveling grid chain distance between one and the next but one cross member.

According to the invention, a device according to the invention is arranged at each of the few points where there is a pressure difference between two adjacent windboxes and designed so that during operation always contact between at least two cross members and the prestressed profile or between the prestressed profile and the grate carriage there is a plate.

In practice, this is between the feed zone and the first drying zone, between the first and second drying zones, between the afterburner zone and the cooling zone and between the cooling zone and the exit zone.

In addition, between the first and second drying zone there is a change in the flow direction, which is to be understood in that in the first drying zone gas flows from the windbox through the grate carriage in the direction of the hood, while in the second drying zone, the gas from the hood the grate carriage flows into the windbox. Usually, the pressure difference between the adjacent windboxes is about 100 mbar. The same situation also exists between the afterburning zone and the cooling zone, since in the afterburning zone gas flows from the hood through the grate carriage into the windbox, while in the cooling zone cold air flows from the windbox through the grate carriage into the hood. Also between the last windbox of the afterburning zone and the first windbox of the cooling zone, a pressure difference in the order of 100 mbar is common. These changes in the direction of flow require the maximum pressure difference between the adjacent wind boxes, which is why it is particularly important to ensure that there are always two grate cross members in direct or indirect contact with the prestressed profile, so that these large pressure differences do not cause the sealing element partially opens. It makes sense to provide at those points where adjacent windboxes have the same pressure, no sealing plate and thus to achieve better Durchgasung the pellet bed on the grate carriage.

The assembly of the profile should preferably be mounted by a flange or a screw, so that when worn the sealing plate, this can be relatively easily replaced.

Preferably, the profile between the at least two wind boxes is formed of a metallic material. If the profile is in direct contact with the grate carriage, ie the profile touches the grate carriage in operation, it has been found to be favorable if the metallic material has an average thickness of between 1 and 50 mm. This ensures that the seal remains stable for a very long time, despite the high temperatures of 500 to 800 ° C.

Furthermore, it has proven to be favorable if the profile is made of steel. Spring steel has proved to be particularly favorable. This ensures a long service life under the prevailing process conditions. In addition, the profile can be preloaded using conventional methods.

In addition, it is favorable to manufacture the sealing plate of a softer material than the grate carriage cross members, so that wear preferably occurs on the side of the sealing plate. It is more cost effective to replace the sealing plates, because the number of cross members is much larger than the number of sealing plates.

An embodiment of the invention provides that the profile can be lowered, whereby a collision with the grate carriage can be prevented in a movement against the usual direction of movement. Also, the insertion of the grate carriage during assembly is facilitated. Preferably, the sealing plate is lifted very slowly after the movement contrary to the usual direction of movement or after placing the grate carriage, while the grate carriage moves in the usual direction. However, can be lowered within the meaning of the invention can also mean that the further profile is lowered or the other profiles are lowered and so the bias of the first profile is canceled.

Finally, the invention also includes a method for the thermal treatment of bulk material with the features of claim 16.

A traveling grate chain runs in the direction of movement, wherein the traveling grate chain contains a plurality of grate carriages, each consisting of two end pieces with wheels and arranged on at least two cross bars grate bars. Moreover, the traveling grate chain at least two wind boxes, which are arranged one behind the other, that flows in at least one wind box gas down or up through the grate carriage. The differential pressure between the two adjacent wind boxes is sealed by guiding the grate carriages over a prestressed profile. This prestressed profile is in direct or indirect contact with the two grate carriages in at least one position of the traveling grate during normal operation.

Next features, advantages and applications of the invention will become apparent from the following description of the drawings. All described and / or illustrated features alone or in any combination form the subject matter of the invention, regardless of their summary in the claims or their back references.

• 1 den Aufbau eines Wanderrostes,
• 2 die erfindungsgemäße Ausgestaltung der Abdichtung als Ausschnitt einer Wanderrostkette im Bereich von zwei Windkästen,
• 3 die erfindungsgemäße Ausgestaltung der Abdichtung aus der Perspektive der Bewegungsrichtung der Wanderrostkette, und
• 4a-f verschiedene Varianten der erfindungsgemäßen Vorrichtung.

Show it:

• 1 the construction of a traveling grate,
• 2 the inventive design of the seal as a section of a traveling rust chain in the range of two wind boxes,
• 3 the inventive design of the seal from the perspective of the direction of movement of the traveling rust chain, and
• 4a-f different variants of the device according to the invention.

1 has already been discussed in detail and represents the basic arrangement of a traveling grate, as it is also the basis of the present invention.

The 2a and 2 B show the cutout of a hiking rust chain 1 , which with two adjacent wind boxes 41 and 43 and three grate trucks 3 ₁ , 3 ₂ and 3 _{3 is shown as} an example. The three grate carriages 3 ₁ , 3 ₂ and 3 ₃ each have a frame 30 on, which consists of two end pieces 33 which extend with their greatest extent in the x-direction, and transverse to which preferably five cross members 32 includes, on the end pieces 33 are fixed and extend with their greatest extent in the y direction. On these crossbeams 32 are in turn the grate bars 35 arranged to receive the lining B of the grate.

The three grate trucks 3 ₁ , 3 ₂ and 3 ₃ pass the windbox 41 and the windbox 43 , Between the two wind boxes 41 and 43 is a profile 50 arranged. The profile 50 can with the sidewalls of the wind boxes 41 and 43 be connected.

When moving the grate carriage in the usual direction of movement they pass the profile 50 between the two neighboring wind boxes 41 and 43 , The cross members are touching 32 the profile 50 , which is thereby deflected elastically, so that a sealing effect between the two wind boxes 41 and 43 arises. This profile 50 is biased, so always a contact force between the profile 50 and the grate bar cross members 32 consists. With dashed lines is in 2a and 2 B hinted how the profile 50 deforms or shifts when a grate cross member 32 is bent downwards. The contact force between the profile 50 and the cross member 32 increases. As in 2a shown, the bias can also by another profile 51 be generated. In this case, a bias of the profile 50 possible, but not essential.

At the profile 50 it can be, as in 2a shown to be a concave shape that is rounded.

Equally, it is also possible that the profile 50 , as in 2 B shown, from a stiff, flat base plate 50 _g exists, which two opposite in the direction of movement arranged side surfaces 50 ¹ _p and 50 ² _p that has, compared to the base area 50 _g are rounded or an angle α which causes these side surfaces 50 ¹ _p and 50 ² _p compared to the base area 50 _g from the grate bar crossbeams 32 remove. This is because there is no edge here where the grate carriages could get caught or hang. It is possible to have such a side surface only at the position first passed in normal operation 50 ¹ _p provide, preferably this side surface 50 ¹ _p However, a second side surface 50 ² _S opposite, so when moving the walking grate 1 contrary to the usual direction of movement snagging or tilting can also be safely avoided. The base plate 50 _g is over an elastic, preloaded further profile 51 up against the cross members 32 of the grate 3 pressed. This prestressed profile 51 is directly or indirectly, for example via a plate 55 , on supports 53 attached, however, is also a fixture directly on the side walls of the wind boxes 41 and 43 possible.

Preferably, the attachment is such that the profile 50 can be exchanged during maintenance. It is also possible according to the invention, the supports 53 to shape that profile 50 and the other profile 51 together with the plate 55 can be lowered so far down that no contact between the grate bar cross members 32 and the profile 50 consists. Similarly, such a reduction can also be done by a suitable mechanical device that the profile 50 by further elastic bias of the other profile 51 pulls down. This lowering is beneficial for operating cases where there is a seal between the adjacent windboxes 41 . 43 is not needed, and thus the contact between the grate bar cross members 32 and the profile 50 is not required. The lowering of the profile 50 reduces the risk of damage to the components in such operating cases and thus also reduces their wear.

3 shows the section through the system according to the invention in the yz plane at the location of a profile 50 , The rust truck 3 also here has a frame 30, of which in this section two end pieces 33 and a crossbeam 32 you can see. At the tails 33 are the wheels 31 assembled. Above the cross member 32 and resting on them are the grate bars 35 which extend with their greatest extent in the x-direction. On these grate bars 35 the coating B is applied. The pad B is through the side wall 34 limited.

When passing the profile 50 is the rust truck cross member 32 at least partially, as in 2 shown with the prestressed profile 50 in connection. The prestressed profile 50 is on supports 53 attached, which can be designed so that the profile 50 is adjustable in height.

The profile 50 itself here has either a concave or a trapezoidal profile.

The 4a to 4f show different embodiments of the other profile 51 or the other profiles 51 ,

4a shows the storage of a sealing plate 50 on a C-shaped profile 51 ₁ , which is preferably designed so that its semicircular side in the direction of movement of the traveling grate 1 extends. 4b shows two superposed C-shaped profiles 51 ₂ , 4c shows an L-shaped profile 51 ₃ , while 4d two successively arranged L-shaped profiles 51 ₃ shows. The 4e and 4f show two successively arranged C-shaped profiles 51 ₁ with different sheet orientation.

LIST OF REFERENCE NUMBERS

1

Pellet burning machine

2

Hood

3

grate carriage

4

Hiking grate, rust truck chain

5

obertrum

6

Continuous conveyors

7

Roller of the grate

8th

inner rail guide

9

outer rail guide

10

Lifting or driving wheel

11

gap

13

Lowering or driven wheel

14

gap

15

strand

30

Grate carriage frame

31

caster

32

crossbeam

33

tail

34

Side wall

35

grate bar

41

first windbox

43

second windbox

50

prestressed profile

50 _g

level surface of the profile

50 ¹ _S , 50 ² _S

Side surfaces of the profile

51

further profile

51 ₁

C-shaped profile

51 ₂

superimposed C-shaped profiles

51 ₃

L-shaped profile

52

Longitudinal wall of the windbox

53

support

55

plate

56

runner

57

Running rail support

α

Angle of the profile side surface

Claims (16)

Apparatus for the thermal treatment of bulk material, comprising a moving in the direction of travel traveling grate chain consisting of an endless traveling grate (1) with movable members, a plurality of grate carriage (3), each consisting of a frame (30) with end pieces (33) on which Impellers (31) are fixed, and arranged on cross members (32) grate bars (35), and wind boxes (41, 43) which are arranged so that from at least one windbox (41, 43) gas through the grate carriage (3) and whose grate bars (35) flow out of or into the windboxes, characterized in that at least one prestressed during operation profile (50,51) is provided, which is arranged so that a component (50) in regular operation in at least one position of the traveling grate (1) is in contact with two cross members (32). Device after Claim 1 , characterized in that the bias of the profile 50 is generated by at least one further prestressed profile 51. Device after Claim 1 or 2 , characterized in that the prestressed profile (50) at undeformed cross member (32) is biased with a ratio of maximum bending stress to yield strength of the material of> 0.2. Device according to one of the preceding claims, characterized in that the profile (50) is a horizontally extending or a curved plate. Device according to one of the preceding claims, characterized in that the profile (50) is a trapezoidal plate. Device according to one of the preceding claims, characterized in that at least two further profiles (51) are arranged one above the other and held together by a heart bolt and / or spring clips. Device after Claim 6 , characterized in that between the at least two further profiles (51) plastic and / or lubrication are provided. Device according to one of the preceding claims, characterized in that the at least one profile (50) is concavely shaped in the prestressed state by branching off either from an intermediate part on two opposite sides a region which has an angle between 1 and 179 ° or rounded to a middle part. Device after Claim 8 , characterized in that the at least one further profile (51) at least one C-profile (51 ₁ ), at least two superposed C-profile (51 ₂ ) and / or at least one L-profile (51 ₃ ). Device according to one of the preceding claims, characterized in that the thickness of the at least one profile (50) decreases towards two opposite sides. Device according to one of the preceding claims, characterized in that in the regular operation of the traveling grate (1) always two grate carriage cross members (32) are in contact with the profile (50). Device according to one of the preceding claims, characterized in that wherever the flow direction of the gas between two wind boxes (41, 43) changes, always two grate carriage cross member (32) are in contact with the profile (50). Device according to one of the preceding claims, characterized in that the profile (50) between the at least two wind boxes (41, 43) is formed of a metallic material having a thickness of 1-50 mm. Device according to one of the preceding claims, characterized in that the profile (50) is made of steel. Device according to one of the preceding claims, characterized in that the profile (50) can be lowered. Process for the thermal treatment of bulk material, comprising a moving in the direction of travel traveling rust chain which an endless Walking grate with movable members, a plurality of grate carriages, each comprising a frame with wheels and grate bars arranged on cross beams and wind boxes, which are arranged so that gas flows through the grate carriages and their grate bars from or into the wind boxes comprises, characterized that two adjacent wind boxes are thereby sealed against each other, that are guided over a prestressed profile, the cross member of the grate carriage and in at least one position, at least one grate carriage cross member is in contact with the prestressed profile.

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