Grate element for a grate cooler

Abstract

 A grate element 10 for a grate cooler for cooling and transporting bulk material in a forward direction, wherein the grate element 10 has at least a box like support structure 20 for an upside facing rest for supporting the bulk material and which has a corner steel like front element 50 being supported by the support structure 20 and comprising a front leg 52 and a top leg 51, wherein the front leg 52 covers a front side of the support structure 20 at least partly and the top leg 51 is positioned on top of the support structure 20 as a part of the rest, may be mounted in simple but reliable manner if the support structure 20 has at least one recess 63 and the front element 50 has at least one protrusion 53 engaging into the recess 63, thereby interlocking the front element 50 against translation in at least a forward direction relative to the grate element 10.

Description

Field of the invention

[0001] The invention relates to a grate element for a grate cooler for cooling and transporting bulk material, like for example cement clinker. The bulk material is cooled by injecting a cooling gas into the bulk material. The grate element has at least a box like support structure for a rest onto which the bulk material can be unloaded. The grate element has a preferably corner steel like front element which is supported by the support structure. The front element comprises at preferably least a front leg and a top leg, wherein the front leg covers the front facing side of the support structure at least partially and the top leg may be positioned on top of the support structure as part of the rest for the bulk material.

Description of the related art

[0002] Clinker, as well referred to as cement clinker is typically sintered in a rotary kiln. The clinker is discharged from the kiln onto a grate cooler. Air or a different cooling gas is injected into the clinker through openings in the grate surface of the cooler, which supports the clinker.

[0003] US-Patent 5,862,906 discloses a clinker cooler with box like grate elements. The grate elements are mounted in rows on beam like grate carriers, which are arranged in parallel to each other. Each row overlaps the row in front of the respective row and thereby the rows of grate elements form a grate floor. The grate floor thus resembles a stair, where each row of grate elements constitutes a step. Some of the grate carriers oscillate forward and backward, thereby transporting the bulk material to a discharge end of the grate floor, where the bulk material is discharged for example into a crusher. Each grate element comprises a box like support structure, supporting grate segments as rest for the clinker. Between the grate segments are slit or slot like nozzles for injecting a cooling gas into the bulk material. The grate segments are inserted one after the other from the open front side of the support structure into guidance rails. The last grate segment is a corner steel like front element. The front element has a front leg and a top leg, wherein the front leg is attached to the front facing side of the support structure by a bolt. The top leg is positioned on top of the support structure as part of the rest and blocks the previously inserted grate segments in the guidance rail.

[0004] US-Patent application 2010/0206288 A1 as well discloses a grate element for a grate cooler with a box like support structure into which grate segments are inserted on guidance rail like grooves. The last, i.e. front facing grate segment is secured by a front plate which is attached by three bolts to the support structure.

Summary of the invention

[0005] The invention is based on the observation that the bolts, by which the front elements are attached to the supporting structure of the grate elements tend to get lost during operation of the grate floor cooler. If this happens, the grate segments slide out of the supporting structure, clinker may enter the support structure and the cooling efficiency is thus reduced. In addition the clinker may over long term destroy the support structure due to abrasion.

[0006] The problem to be solved by the invention is to provide a grate surface where the grate segments are secured against getting lost, even in case the prior art bolts break or get unscrewed due to vibrations, thermal stress or the like.

[0007] Solutions of the problem are described in the independent claims. The dependent claims relate to further improvements of the invention.

[0008] A grate element of the present invention can be a part of a grate cooler for cooling and transporting bulk material in a forward direction, for example from a kiln to some further processing unit. The further processing unit may be for example a crusher, a bulk tank or a bunker. The grate element has at least a box like support structure for an upside facing rest for supporting the bulk material. The rest may for example be formed by grate segments covering the box like support structure. Ventilation slits or nozzles may be formed in and/or between the grate segments. The grate segments, as well referred to as grate bars, may be inserted for example via an opening in the front or rear wall of the support structure. The support structure may comprise guidance rails for inserting grate segments. The grate element further comprises at least one front element, the latter being supported by the support structure. The front element may be corner steel like and may thus comprise at least a front leg and a top leg. The front leg covers a front side of the support structure at least partly. For example the front leg may close an opening in the front wall of the support structure, via which for example grate segments could be inserted. The top leg is preferably positioned on top of the support structure as part of the rest. The front element may preferably block the grate segments in their respective intended positions. The support structure has at least one recess and the front element has at least one protrusion engaging into the recess, thereby blocking the front element against translation at least in a forward direction relative to the grate element. Additional bolts may be used to further attach the front element to the support structure, however even if these bolts get lost during operation of the grate cooler, the front element will rest in its intended position and may still block the grate segments in their intended respective positions.

[0009] The terms forward direction, front side, front wall, rear side, rear wall and the like refer to the orientation given by the direction of transportation of the bulk material, i.e., the outlet of the grate floor cooler faces in the forward direction.

[0010] Preferably, at least the distal part of the protrusion has the form of a ring segment and the recess has at least a complementary ring segment like section. The protrusion can thus be inserted into the recess by pivoting the front element. The front element and the support structure are thus releasable connected by pivoting the protrusion into the recess. Such pivotal fastening permits a simple and reliable interlocking of the front element with the support structure.

[0011] The pivotal fastening has pivot axle, which is preferably parallel to a front edge of the support structure. Thereby, a translation of the front element in the direction of transportation of the bulk material can be prevented.

[0012] The pivotal fastening may have a pivot axle that coincides with the top rear edge of the top leg or is above and/or behind the top rear edge of the top leg. Such pivotal fastening ensures that the front element is pushed downwards by the bulk material moving over the top leg. In addition, the grate segments or more general the front side of the rest may not block the front element, when inserting the protrusion into the recess by pivoting the front element relative to the support structure. In contrast, the front element may block elements of the rest, for example grate segments in guidance rails.

[0013] If the protrusion extends from the bottom side or rear side of the top leg into the recess and if the recess extends from the upward facing surface of the support structure into the support structure, the front element can be mounted and replaced very easily, even in a built in situation of the grate element.

[0014] Preferably a spacer or an adjustment plate is positioned, e.g., clamped, between the front leg and the front facing side of the support structure. The space permits to define and adjust a moving gap, being formed by the slit between the lower side of an overlapping part of a grate element and the top facing surface of a subsequent grate element. The spacer may in a preferred embodiment have the form of flat bar with a downward facing straight edge or plane surface, being at least substantially parallel to the rest and thereby to the rest of the subsequent lower grate element. The straight edge or plane surface of the spacer extends preferably over the full width (±25%) of the rest.

[0015] The front element may be fastened by at least one bolt to the support structure. The at least one bolt may prevent the front element from unintended pivoting. The at least one bolt may be screwed via the front leg into the support structure.

[0016] The box like support structure preferably houses a cross beam supporting at least one thread for the at least one bolt. The cross beam may be blocked by the front wall. This yields an easy to mount and, however, stable connection of the front plate with the support structure via the bolt. The cross beam may preferably be mounted floatingly, thereby reducing unintended strain to the cross beam, the bolt, the support structure and/or the front element. "Mounted floatingly" means that he cross beam can be moved within float limits relative to the front wall of the box like support structure. The cross beam may for example have at least one whole with a thread for a bolt and/or may support as least one screw nut as counterpart for a bolt.

[0017] In addition, the box like support structure preferably houses a retaining member, engaging with the cross beam and positioning the at least one thread in alignment with at least one opening in a front wall of the support structure. This permits to define the limits of float of the cross beam in the box like support structure.

Description of Drawings

[0018] In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with reference to the drawings.

Figure 1 shows an isometric view of a detail of a grate cooler.

Figure 2 shows a support structure of a grate element.

Figure 3 shows an isometric view of a partially mounted grate element.

Figure 4 shows the partially mounted grate element from a different perspective.

Figure 5 shows an isometric view of two grate elements.

Figure 6 shows two grate elements from a different perspective.

Figure 7 shows a detail of Figure 6.

Figure 8 shows a further detail of Figure 6.

[0019] Figure 1 shows an isometric view of a detail of a grate cooler for cooling bulk material like for example cement clinker. The grate cooler comprises grate elements 10 being positioned in rows one beside another on beam like grate carriers 5, which are arranged in parallel to each other. Each row of grate carriers overlaps the subsequent row. Thus the grate elements 10 form a stepped grate floor, where each row of grate elements 10 forms a step. At least one of the grate carriers 5 may be powered to oscillate forward and backward, as indicated by double arrow 6. When a row of grate elements 10 is moved forward, it pushes bulk material in a forward direction, and when it is subsequently retracted bulk material fills the resulting space and with the next forward movement the bulk material is again pushed forward. Thus, by the oscillating movement of at least some of the rows the bulk material is transported. The bulk material may as well be cooled. To this end a cooling gas may be provided through the grate carriers 5 to the grate elements 10 and is blown through slit like nozzles 12 (see Fig. 3) into the bulk material.

[0020] Figure 2 shows an isometric view of a support structure 20 of a grate element 10. The support structure 20 is box like and can be for example made from some sheet material: The rear wall 21, the front wall 22 and the side walls 23 can be folded upwards to form an open box. The remaining sheet material forms a base plate 28. The base plate has an opening, through which a cooling gas is fed to the grate element. Attached to the base plate is a clamping fixture 27 for attaching the support structure 20 and thereby the grate element 10 to a grate carrier 5. Attached to the base plate 28 and/or the side walls 23 are guidance rails 26, which are preferably at least substantially parallel to the side walls 23. In each of the side walls 23 of the support structure 20 is a recess 63 with a ring segment like shape into which a protrusion of a front element 50 may be inserted, as will be explained below.

[0021] Figure 3 shows the grate element 10 after the next assembly step. Figure 4 shows the grate element of Fig.3 from a different perspective. In both figures a part of the support structure 20 is covered by a cover plate 24 and grate segments 25. The cover plate 24 and the grate segments 25 have been inserted into the guidance rails 26 through an opening in the front side of the support structure 20 and form part of the rest for the bulk material. A cross beam 30 with press fitted screw nuts 34 is inserted into the support structure 20, just behind the front wall 22, as indicated by arrows 33. Both distal ends of the cross beam 30 are slightly bent to the rear and have a slit like opening into which a nose like protrusion 42 of a retaining member 31 engages. The retaining member 31 cross beam 30 assembly positions the nuts 34 in alignment with through holes 44 in the front wall 22. As will be explained later, the nuts 34 are counterparts of bolts 35 for fastening a front element 50 (see Fig. 5). When fastening the bolts 35, the nuts are blocked by the rear side of the front wall 22.

[0022] Fig. 5 shows two grate elements 10 forming a step. As can be seen, a front element 50 has been attached to each of the support structures 10, thereby blocking the grate segments 25 and the cover plates 24 in their positions. Only for purpose of explanation the front element 50 of grate element 10 of the 'upper step' is not yet fully mounted. This is depicted in detail in Fig. 7. The front element 50 is a corner steel like profile with a top leg 51 and a front leg 52. On the bottom side of the top leg 51 is a ring segment like protrusion 53. In each of the side walls 23 is a recess 63, into which the ring segment like protrusion 53 can be inserted by pivoting the front facing side front element 50 downwards. The pivot axle coincides with the rear facing side of the top leg 51 of the front element 50. Thus, the rear facing side of the front element, in particular the rear facing side of the top leg 51, blocks the grate segments 25 and the cover plate 24.

[0023] Before pivoting the front element 50 downwards one may insert a spacer 70 between the front wall 22 and the rear side of the front leg 52 of the front element 50 (see Fig. 5 and Fig. 6). The spacer 70 permits to adjust the gap between the 'upper' grate element 10 and the subsequent (in the forward direction) grate element 10.

[0024] Subsequently the front element is pivoted downwards and fixed in its position by bolts 35 (see Fig. 5). When fastening the bolts 35, the spacer 70 can be clamped at a well defined height above cover plate 24 of the lower grate element 10, thereby defining a moving gap between the succeeding grate elements 10. The height of the spacer 70 and thus the height of the motion gap may be adjusted using a settle jig.

[0025] The fully mounted position of the front element is shown in Detail in Fig. 8: The protrusion 53 is inserted in a form fitting manner into the recess 63. The top leg 51 forms, together with the grate segments 25 and the cover plate 24 (not shown, see Fig. 5), a rest for supporting the bulk material. Even if all of the three bolts 35 get lost, the front element 50 will remain in its intended position and block the grate segments 25 and the cover plate 24, thereby preventing them from getting lost as well.

List of reference numerals

[0026] 

5

grate carrier

6

arrow indicating the oscillating movement of the grate carrier 5

10

grate element

12

nozzle

20

support structure

21

rear wall of support structure

22

front wall of support structure

23

side wall of support structure

24

cover plate

25

grate segment

26

guidance rail

27

clamping fixture

30

cross beam

31

retaining member

33

arrow

34

nut

35

bolt

42

protrusion of a retaining member

44

through holes

50

front element

51

top leg

52

front leg

53

protrusion

54

opening for bolt

63

recess

70

spacer

71

arrow indicating direction of spacer, when mounting

Claims

1. A grate element (10) for a grate cooler for cooling and transporting bulk material in a forward direction, wherein the grate element (10)

- has at least a box like support structure (20) for an upside facing rest for supporting the bulk material,

- has a front element (50) which is supported by the support structure (20) and covers at least a section of the front side of the support structure (20)
characterized in that
the support structure (20) has at least one recess (63) and the front element (50) has at least one protrusion (53) engaging into the recess, thereby interlocking the front element (50) against translation in at least a forward direction relative to the grate element.

2. The grate element (10) of claim 1
characterized in that
at least the distal part of the protrusion (53) has the form of a ring segment, the recess (63) having at least a complementary ring segment like section, thereby forming a pivotal fastening of the front element (50) with the support structure (20).

3. The grate element (10) of claim 2,
characterized in that
the pivotal fastening has pivot axle being parallel to a front edge the support structure.

4. The grate element (10) of claim 2 or 3,
characterized in that
the pivotal fastening has pivot axle that coincides with the top rear edge of the top leg (51) or is above and/or behind the top rear edge of the top leg.

5. The grate element (10) of claim 1
characterized in that
the front element (50) has a corner steel like shape with at least a front leg (52) and a top leg (51), wherein the front leg (52) covers the front side of the support structure (20) at least partly and the top leg (51) is positioned on top of the support structure (20) as a part of the rest

6. The grate element (10) of claim 5
characterized in that
the protrusion (53) extends from the bottom side or rear side of the top leg (51) into the recess (63) and in that the recess (63) extends from the upward facing surface of the support structure (20) into the support structure.

7. The grate element (10) of one of claims 5 or 6,
characterized in that
an spacer (70) is clamped between the front leg (52) and the front facing side of the support structure (20).

8. The grate element (10) of one of claims 1 to 7
characterized in that
the front element (50) is fastened by at least one bolt (35) to the support structure (20).

9. The grate element (10) of claim 8,
characterized in that
the box like support structure (20) houses a cross-beam (30) supporting at least one thread for the at least one bolt (35), the crossbeam (30) being blocked by the front wall (22).

10. The grate element (10) of claim 9
characterized in that
the box like support structure (20) houses a retaining member (31), engaging with the cross beam (30) for positioning the at least one thread in alignment with at least one through hole (44) in a front wall (22) of the support structure (20).

11. Grate cooler for cooling bulk material,
characterized in that
it comprises at least one grate element (10) of at least one of the preceding claims.

Drawing