EP0537523B1 - Cooling grate - Google Patents

Description

The invention relates to a cooling grate of a grate cooler for hot goods, according to the preamble of claim 1. In particular, this invention is concerned with a cooling grate intended for a so-called moving grate cooler.

Grate coolers with a cooling grate of the type required in the preamble of claim 1 are known in various embodiments. For example, DE-AS 20 11 518 shows a cooling grate design in which the individual grate plates have vertically upwardly projecting ribs in their parts through which cooling air flows, which delimit box-shaped troughs, in the bottoms of which vertically running, conical bores for the passage of Have cooling air.

In another known embodiment (DE-OS 38 12 425), the individual grate plates are designed with troughs open to the upper side of the wings for receiving material to be cooled, the cooling gas through openings also opening into the trough area here. In addition, at least some radiator grate plates can be formed with hollow ribs running in the conveying direction for the cooling gas guidance, wherein the cooling gas passage openings can be provided in these longitudinally extending hollow ribs.

In the known designs described above, in particular the grate plates belonging to the grate cooler or the cooling grate, it has proven difficult to jointly meet some essential requirements for such grate plates. For example, a cheap one Manufacturing ability can be guaranteed and it can be ensured that at the same time an optimal cooling gas distribution, sufficient cooling of the wing sections in contact with the hot material of the grate plate and, above all, intensive cooling of the goods transported over the cooling grate is achieved.

The invention is therefore based on the object of providing a cooling grate of the type required in the preamble of claim 1, in which the requirements explained above (in particular in the area of the grate plates) can be met together in a particularly advantageous manner.

This object is achieved by the training according to the characterizing part of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

In the embodiment according to the invention, at least one pocket-shaped recess is worked into the supporting surface of each grate plate from above, which has at least one window-like through hole (ie a correspondingly large, free through opening) at its bottom and in which a strip-shaped ventilation cover cap is fitted and arranged in this way that a cooling air passage opening is formed in the form of an essentially closed annular gap. This results in a cooling gas duct within each grate plate, through which practically all areas of the wing sections coming into contact with hot material (eg hot cement clinker coming from a furnace) can be optimally cooled by an appropriately high air speed in the annular gap. The cooling gas emerging from these annular gap-shaped through openings also sweeps over the side surfaces of the annular gap regions and thus provides additional heat dissipation at the lower region of the grate plates.

The cooling gas resistance can be predetermined by the gap width of the cooling gas passage openings in the manner required. Above all, it can also be ensured that the cooling gas itself is supplied at a sufficiently high speed for cooling the grate plates or their wings, whereas the cooling gas speed in the area in which the cooling gas enters the material to be cooled, can be reduced so significantly that an optimal gas distribution in the material and thus a particularly intensive cooling of the hot material is made possible.

With this extremely favorable cooling gas routing through the annular-shaped cooling gas passage openings, the multi-part design of each grate plate (which is formed in each case from the plate base or main body and at least one correspondingly designed and arranged ventilation cover cap) also proves to be particularly advantageous from a production point of view if these plate parts are manufactured as castings. If one compares this with the known embodiment according to DE-OS 38 12 425 explained above, it will be found that it is extremely difficult with the grate plate, which is obviously made in one piece, defined passage cross-sections for the cooling gas through openings in one casting.

Fig.1

eine Teil-Längsschnitt-Ansicht durch einen erfindungsgemäßen Kühlrost;

Fig.2

einen Längsschnitt durch eine Rostplatte dieses Kühlrostes, etwa entlang der Linie II-II in Fig.3;

Fig.3

eine Aufsicht auf die Rostplatte gemäß Fig.2 (wobei eine Belüftungs-Abdeckkappe entfernt ist);

Fig.4

einen Querschnitt durch die Rostplatte, entsprechend Schnittlinie IV-IV in Fig.2;

Fig.5

eine Unteransicht lediglich einer Belüftungs-Abdeckkappe;

Fig.6

eine Aufsicht auf eine andere Ausführungsform einer Rostplatte;

Fig.7

eine Querschnittsansicht entlang der Linie VII-VII in Fig.6;

Fig.8

eine weitgehend schematisch gehaltene Teil-Querschnittsansicht eines quer verlaufenden Rostplattenträgers mit mehreren darauf angeordneten Rostplatten;

Fi.9

einen Längsschnitt ähnlich Fig.2, jedoch durch eine flache Rostplatte;

Fig.10, 11 und 12

Längsschnittansicht, Aufsicht und Querschnittsansicht einer weiteren Ausführungsvariante der Rostplatte;

Fig. 13 und 14

Längsschnittansicht und Aufsicht einer anderen Rostplattenvariante.

The invention is explained in more detail below with the aid of some exemplary embodiments illustrated in the accompanying drawing. Show in this drawing

Fig. 1

a partial longitudinal sectional view through a cooling grate according to the invention;

Fig. 2

a longitudinal section through a grate plate of this cooling grate, approximately along the line II-II in Figure 3;

Fig. 3

a top view of the grate plate according to Figure 2 (with a ventilation cap removed);

Fig. 4

a cross section through the grate plate, according to section line IV-IV in Figure 2;

Fig. 5

a bottom view of only a ventilation cap;

Fig. 6

a top view of another embodiment of a grate plate;

Fig. 7

a cross-sectional view taken along the line VII-VII in Figure 6;

Fig. 8

a largely schematic partial cross-sectional view of a transverse grate plate carrier with a plurality of grate plates arranged thereon;

Fi.9

a longitudinal section similar to Figure 2, but through a flat grate plate;

Fig. 10, 11 and 12

Longitudinal sectional view, top view and cross-sectional view of a further embodiment of the grate plate;

13 and 14

Longitudinal section view and supervision of another grate plate variant.

The general structure of the cooling grate according to the invention will first be explained with reference to FIG. Of this cooling grate, only the parts necessary to explain the invention are illustrated for the sake of simplicity and clarity. Overall, this cooling grate belongs to a grate cooler, in particular a moving grate cooler, which is used for cooling hot goods, such as hot cement clinker coming from an upstream furnace is determined, the material to be cooled being longitudinal, i.e. is transported in the direction of arrow 1 over the cooling grate.

This cooling grate contains, in a manner known per se, a multiplicity of rows of grate plates 2 which adjoin one another in the longitudinal direction and overlap. The grate plates of each row which are adjacent to one another in the grate transverse direction are each fastened to a grate plate support 3 which runs transversely to the grate, in FIG. 1 only one of these grate plate supports 3 is illustrated. This grate plate carrier 3 is designed as a hollow body and for the supply of cooling gas (arrows 4) from below and with a cooling gas chamber or source not shown in detail connected, as cooling gas - as known per se - cooling air can be used.

Each grate plate 2 has an airfoil 5, through which the material to be cooled is transported along.

As can be seen on the middle grate plate 2 in FIG. 1 and even more clearly in FIGS. 2 to 3, at least one pocket-shaped depression 6 is worked into the supporting surface 5 of each grate plate 2, which is at least one relative to its base 7 has large, free, window-like through hole 8. In the first embodiment illustrated in FIGS. 1 to 4, two pocket-shaped depressions 6 are preferably provided in the grate plate 2 or its supporting surface 5. In this case, a strip-shaped ventilation cap 9 is also fitted and arranged in each recess 6 in such a way that cooling gas through-openings 10 opening out towards the top of the wings 5 are in the form of essentially closed annular gaps, i.e. these annular gap-shaped cooling gas through openings 10 are delimited on the one hand by the approximately upright inner sides 6a of the pocket-shaped recesses 6 and on the other hand by the outer peripheral edge 9a of the ventilation cover caps 9.

It is also important that between the bottom edge area 9b of each ventilation cap 9 and the edge area 7a of the recess bottom 7 opposite this edge area there is formed an essentially annular cooling gas inlet slot 11, the clear width of which is appropriately distributed by the arrangement of several arranged Distance elements 12 can be determined. These spacer elements 12 are preferably attached in one piece in a corresponding distribution on the underside of each ventilation cap 9, as indicated in FIG. 5.

As can be seen in FIGS. 1, 2 and 4, it is preferred that the bottom 7 of each wing recess 6 on its central section covered by the associated ventilation cap 9 opposite its remaining peripheral edge surface, that is to say those under the associated annular-gap-shaped cooling gas Passage opening 10 lying edge area is increased. The peripheral edge region 7a of the base 7 already mentioned above is formed on this raised central base section, preferably in such a way that - viewed in the cross section of the grate plate 2 - it slants outward-downward in the direction of the lower section of the associated annular-gap-shaped cooling gas Passage opening 10 has. Corresponding to this beveling of the peripheral edge 7a, the lower or lower edge region 9b of the associated ventilation cap 9 is also inclined obliquely outwards and downwards over the entire circumference. In this way, the cooling gas passage slot 11 formed between these two circumferential edge regions 7a and 9b, which are at a distance from one another and viewed in vertical section through the grate plate 2, is also inclined downward in the cooling gas entry direction (arrows 4 in FIG. 1), specifically in the way that it opens over its entire circumference in the lower section of the associated annular gap-shaped cooling gas passage opening 10 (see. Fig. 1 and 2). This design and arrangement of the cooling gas inlet slots 11 (in cooperation with the cooling gas through openings 10 and a corresponding cooling gas speed) can be reliably prevented that no fine portions of the good to be cooled can fall down through the grate plate 2 or its cooling gas passage openings 10.

In the case of the upper recess 6 in FIG. 3, which is not covered by a cover cap 9, and also, above all, in the sectional representations in FIGS having a plurality of bores 14. These holes 14 are intended for receiving fastening bolts 15, which each ventilation cap 9 has on its underside. These downwardly projecting fastening bolts 15 are inserted so far into the holes 14 in the supporting webs 13 of the raised bottom section that they are fixed, preferably welded, in the appropriate height position of the cover cap 9. This height of the cover cap relative to the raised portion of the recess base 7 lying underneath thus also determines the clear width of the annular cooling gas inlet slot 11, as can be seen easily in FIGS. 1 and 2.

The ventilation cover caps 9 all have a substantially flat upper side. In the preferred embodiment of the grate plate 2 illustrated in these FIGS. 1 to 4, the arrangement of the raised middle section of the floor 7 and the ventilation cover cap 9 is such that the top side 9c of the cover cap 9 is opposite the top plane 5a of the wing 5 is lowered by the dimension A (Fig.2). In this way there is an additional 6 in the associated recess a ventilation pocket 16 is also formed in the area above the ventilation cover cap 9, which can fill with material during the cooling operation of the cooling grate or grate cooler and can thereby particularly advantageously protect this area of the grate plate 2 or airfoil 5 against wear. A further advantage of these ventilation pockets 16 during cooling operation is that the cooling gas emerging from the annular gaps 19 in these ventilation pockets above the cover caps 9 form a kind of fluidized bed of the goods stored therein, which then enters a relatively large area into the refrigerated goods bed above it and thus one optimal cooling of the goods favors.

In general, the cooling gas through openings 10 delimited by the depressions 6 and the ventilation cover caps 9 could have any suitable elongated annular gap shape running in the direction of the goods to be conveyed (arrow 10), insofar as this allows the largest possible cooling gas passage or exit from the grate plate 2 in the refrigerated goods bed is guaranteed. In the experiments on which the invention is based, however, it has proven to be particularly advantageous if the depressions 6 and the ventilation cover caps 9 inserted therein have an elongated rectangular shape in such a way that the annular gaps forming the cooling gas passage openings 10 have a top view have an elongated rectangular shape closed on the wing 5 (cf. FIG. 3), the long sides of the rectangle running essentially parallel to the conveying direction (arrow 1) of the goods to be cooled.

What the number of recesses 6 with associated ventilation caps 9 in each wing 5 or Regarding grate plate 2, this number generally depends on the respective plate size (base area); With the grate plate sizes that have been customary in practice up to now, it has proven to be particularly advantageous to provide in each grate plate 2 only two recesses 6 / ventilation cover caps 9 that are matched to the supporting surface 5 and thus two correspondingly large, circular-gap-shaped cooling gas passage openings 10. In this context, it should also be mentioned that - as can also be seen in FIGS. 1 to 3 - the depressions 6 with their ventilation cover caps 9 can only be arranged in the larger longitudinal section of the grate plate 2, which is in the front in the direction of material conveyance (arrow 1) the reciprocating pushing movement of the rows of grate plates is not brushed by the grate plates 2 lying above them (cf. illustration in FIG. 1).

A second exemplary embodiment for the formation of grate plates for the cooling grate according to the invention will first be described with reference to FIGS. 6 and 7. Here, too, it should be assumed in the preferred manner that the grate plate 2 'or its supporting surface 5' has two evenly distributed cooling gas or cooling air passage openings 10 'on its front longitudinal section pointing in the direction of material conveyance (arrow 1), which openings 10' face towards the top of the Open wing 5 'open and are again in the form of substantially closed annular gaps. It should also be assumed here that two such cooling gas passage openings 10 'in the form of an annular gap are correspondingly evenly distributed with an adapted size and elongated rectangular shape and are adapted to the area size.

In addition, the annular-gap-shaped cooling gas through openings 10 'are also formed by incorporating two pocket-shaped recesses 6' from above into the support surface 5 'of the grate plate 2', which have a plurality of through holes 8 'on their base 7' and into each of them a strip-shaped ventilation cap 9 'are fitted and arranged to form the said annular gap. In contrast to the first example described above, however, each ventilation cap 9 'has a flat upper side which is flush with the upper side of the wing 5' (see FIG. 7).

While in the first exemplary embodiment (in particular FIGS. 1 to 4) the annular-gap-shaped cooling gas through-openings 10 are oriented essentially perpendicularly or vertically to the upper side 5a of the wings 5, FIGS. 6 and 7 show an embodiment according to which the flow direction (arrow 1) of the longitudinal sections of the rectangular, annular-gap-shaped cooling gas passage openings 10 ', which run to be cooled, are inclined to the vertical, ie All longitudinal sections of the annular-gap-shaped cooling gas passage openings 10 'of a grate plate 2' are inclined in one direction at approximately the same angle to the vertical (cf. cross section in FIG. 7).

In this embodiment of the cooling gas through openings 10 ', again in a similar, correspondingly adapted manner, it is further ensured that an essentially annular circumferential cooling gas inlet slot is provided between the underside edge region of each ventilation cap 9' and the opposite edge region of the recess bottom 7 ' 11 'is formed, which can be predefined and adjusted in its clear width according to the respective requirements. Here, too - as illustrated in the cross section of FIG. 7 - the cooling gas inlet slot 11 'can be inclined downward in the cooling gas inlet direction and open into the lower section of the associated annular-gap-shaped gas passage opening 10' - largely without transition.

FIG. 8 also shows a partial cross-sectional view of a grate plate carrier 3 ′, again designed as a hollow body, which is designed for the supply of cooling gas from below and on its top side a series of grate plates placed next to one another in the transverse direction - for example in the embodiment according to FIGS 7 - carries. Here, as in the first example according to FIG. 1, the grate plates 2 '(or 2) can be designed and fastened on the grate plate supports 3' (or 3) in such a way that at least the bottom 7 '(or 7) of the Recesses 6 '(or 6) and the ventilation cap 9' (or 9) arranged above them can be flowed freely from below by the cooling gas (dashed arrows 4).

If it is also assumed in FIG. 8 that grate plates 2 'of the type described with reference to FIGS. 6 and 7 are fastened to the grate plate support 3' there, it is preferred to arrange these grate plates 2 'in such a way that - in cross section of the cooling grate viewed and in each case starting from the vertical longitudinal center plane 17 - the longitudinal sections of the cooling gas passage openings 10 'located on the two transverse halves of this cooling grate are each inclined toward the closest outer longitudinal side of the cooling grate.

In this way, the cooling gas emerging from the cooling gas passage openings 10 'upward (indicated by arrows 4 in FIG. 8) can to a large extent in the transverse direction to the material conveying direction (arrow 1 in FIG. 3 or perpendicular to the plane of the drawing in FIG. 8) enter the goods to be cooled.

With all grate plate designs and possible assignments to the grate plate carrier, it is expedient to select the clear width of the cooling gas passage slots 11, 11 'in such a way that the approximately equal amounts of cooling gas can be supplied to the grate plates 2, 2' charged by a grate plate carrier section, i.e. the amount of cooling gas supplied can be evenly distributed over the corresponding grate plates.

In this embodiment according to the invention, in particular the grate plates, and in particular the grate plates 2 according to the embodiment explained with reference to FIGS. 1 to 5, a kind of tripartite division of the cooling gas duct can be brought about, namely on the one hand a relatively high gas speed (for example about 40 m / s) in the area of the cooling gas inlet slots 11, on the other hand a gas speed which is correspondingly reduced by the larger opening cross section (approximately in the range from 12 to 15 m / s) in the area of the annular gap-shaped cooling gas through openings 10 and thirdly by one in the area of the Ventilation pockets 16 very greatly reduced gas speed, which is only a few m / s (possibly only slightly greater than 0). This three-stage cooling gas guide ensures that the wing sections coming into contact with hot material are each Grate plate 2 are adequately cooled, prevents fine parts from penetrating into the cooling gas inlet slots and optimal distribution of the cooling gas escaping upwards in the goods to be cooled (bed) and thus an optimal, very intensive cooling effect is achieved.

Within the scope of the invention, the exemplary embodiments described so far can be varied in a meaningful manner, the basic principles of this cooling grate according to the invention, in particular the associated grate plates, always being maintained. Some of these possible design variants are explained below with reference to FIGS. 9 to 14.

9 shows an embodiment variant in which the individual grate plates 22 largely correspond in their structural design to the construction of the exemplary embodiment explained with reference to FIGS. 1 to 5, so that all grate plate parts of the same type are also provided with the same reference numerals. There are thus preferably also two similar pocket-shaped depressions 6 incorporated into the supporting surface 5 of the grate plate 22, on the bottom 7 of which in turn a strip-shaped ventilation cover cap 9 is arranged in such a way that a cooling gas passage opening 10 results in the form of a closed annular gap . The special feature of this embodiment variant can be seen in the fact that each of these grate plates 22 is essentially flat and has no special ventilation pocket (see. Ventilation pocket 16 in FIG. 2), ie in the case of these grate plates 22 each essentially flat upper side of the ventilation cover cap 9 flush with the top of the wing 5 (About the same as described with reference to Figure 7 of the second embodiment).

The further embodiment variant illustrated with reference to FIGS. 10, 11 and 12 also starts from the basic construction of the first exemplary embodiment described with reference to FIGS. 1 to 5, so that here, too, the same grate plate parts are provided with the same reference numerals. It can be seen in particular from FIGS. 11 and 12 that here, too, two equally sized pocket-shaped depressions 6 are formed in the supporting surface of each of the grate plates 32 shown here, into each of which a strip-shaped ventilation cover cap 9 is fitted and arranged on the bottom 7 is that there is a cooling gas passage opening 10 in the form of a closed annular gap. Furthermore, the essentially flat upper side 9c of each ventilation cap 9 is additionally lowered by a suitable dimension A with respect to the upper side 5a of the wing 5 with the additional formation of a ventilation pocket 16 (similar to the first exemplary embodiment in FIGS. 1 to 5).

If one considers the graphic representations in this embodiment variant in FIGS. 10 to 12, it is particularly clear here that each recess 6 is primarily composed of two longitudinal webs which are arranged at a distance from one another and parallel to one another and to the material conveying direction (arrow 1), namely the webs 33, 34 on the one hand and the webs 34 and 35 on the other hand, as well as a front end web 36, viewed in the conveying direction (arrow 1), which runs across the entire grate plate 32. Compared to the first embodiment (see in particular Fig. 4) This embodiment variant of FIGS. 10 to 12 differs primarily in that, in addition to the front web 36, only the two outer longitudinal webs 33 and 35 extend to the height of the wing top 5a while forming an approximately box-shaped common ventilation pocket 16 the upper edge 34a of the central longitudinal web 34 lies approximately at the level of the upper sides 9c of the two ventilation cover caps 9. Thus, in this embodiment variant, the height of the central longitudinal web 34 is reduced compared to the other longitudinal webs 35, 36.

The embodiment variant of grate plates 42 illustrated with reference to FIGS. 13 and 14 also deals with the formation of the ventilation pockets 16 in the area above the ventilation cover caps 9. In this context, if one connects to the previous explanations with reference to FIGS. 10 to 12, then In this embodiment variant according to FIGS. 13 and 14, only the front end web 36 extends to form the ventilation pocket 16 up to the height of the wing top 5a. In contrast, all longitudinal webs 33, 34 and 35 extending in the direction of material conveyance (arrow 1) are only guided up to the height of the upper sides 9c of the ventilation cover caps 9, ie their upper edges lie approximately in the same plane as the upper sides of these ventilation cover caps 9. The ventilation pocket In this embodiment variant 16 is therefore mainly limited by the front end web 36 and of course also by the rear part (see wing 5) of these grate plates 42, as viewed in the direction of good conveyance (arrow 1), as can be seen from FIG. 13 .

In addition, in a further modification of these two last-explained design variants (corresponding to FIGS. 10 to 12 and 13 and 14), it is also possible that only one outer longitudinal web (35 or 36 ) extends to the height of the wing top 5a, while the other outer longitudinal web and the middle longitudinal web with their upper edges lie approximately at the level of the top 9c of the ventilation cover caps 9. This further modification is particularly expedient if grate plates 42 according to FIGS. 13 and 14 are arranged over the largest part of the grate width (i.e. in the transverse direction of the grate), while in the last modification of the longitudinal webs only the outer longitudinal web up to in the height of the wing top 5a is drawn up, which is adjacent to an outer longitudinal side of the cooling grate, so that nothing can fall to the outside from the refrigerated goods accumulated on the grate plate or in its ventilation pocket 16.

With regard to the longitudinal webs reduced in height in accordance with the embodiment variants previously described with reference to FIGS. 10 to 14, it should also be mentioned that advantages can thereby be achieved in that the webs reduced in height only come into contact with hot refrigerated goods in a greatly reduced proportion and are therefore exposed to less thermal stress and less abrasion. In addition, webs which are reduced in height in this way can also be produced, in particular cast, at lower costs.

The explained additional design variants also make it clear once again that the designs according to the invention Grate plates and thus also the cooling grate according to the invention can be adapted to the different operating conditions and cooling goods in an extremely advantageous manner.

Claims (16)

1. Cooler grate of a grate cooler for hot material, containing a plurality of grate plates (2, 2') which are fixed on grate plate supports (3, 3') running transversely with respect to the cooler grate and which each have a supporting surface (5, 5') for material to be cooled which is transported over the cooler grate, cooling gas openings (10, 10') being provided in the supporting surfaces and opening towards the upper faces of the latter, characterised in that the supporting surface (5, 5') of each grate plate (2, 2') has produced in it from above at least one pocket-shaped recess (6, 6') which has on its base (7, 7') at least one through hole (8, 8') and into which a strip-shaped aeration cap (9, 9') is fitted and arranged in such a way that in each case a cooling air opening (10, 10') in the form of a substantially closed annular gap is constructed.
2. Cooler grate as claimed in claim 1, characterised in that between the underside edge region (9b) of each aeration cap (9, 9') and the opposite edge region (7a) of the base (7, 7') of each recess (6, 6') a cooling gas inlet slot (11, 11') is constructed which also runs round in a substantially annular shape, and the internal width of this slot can be determined by the arrangement of distance pieces (12).
3. Cooler grate as claimed in claim 2, characterised in that the base (7) of each supporting surface recess (6) is raised in its central section covered by the appertaining aeration cap (9) relative to the rest of its peripheral edge surface, and the cooling gas inlet slot (11, 11') - when viewed in the cross-section of the grate plate - is inclined downwards in the direction of entry (4) of the cooling gas and opens into the lower section of the appertaining cooling gas opening (10, 10') in the form of an annular gap.
4. Cooler grate as claimed in claim 3, characterised in that each aeration cap (9) has on its underside several bolts (15) which project downwards and are passed through holes (14) in the raised base section of the appertaining recess for fixing on the recess base (7).
5. Cooler grate as claimed in claim 1, characterised in that each aeration cap (9) has a substantially flat upper face (9c) which lies lower than the upper face (5a) of the supporting surface (5) in the appertaining recess (6) and forms an aerating pocket (16).
6. Cooler grate as claimed in claim 5, characterised in that each recess (6) is defined by two longitudinal bars (33, 34, 35) which are arranged spaced from one another and extend parallel to one another and to the material conveying direction (1) as well as an end bar (36) which is at the front - when viewed in the material conveying direction (1) - in which case at least this end bar (36) extends to the height of the upper face (5a) of the supporting surface for the formation of the aerating pocket (16).
7. Cooler grate as claimed in claim 6, characterised in that in the case of at least two recesses (6) produced in each grate plate (32) the two outer longitudinal bars (33, 35) also extend to the height of the upper face (5a) of the supporting surface, thus forming a common aerating pocket (16) which is approximately box-shaped.
8. Cooler grate as claimed in claim 6, characterised in that in the case of at least two recesses produced in each grate plate (42) both the two outer longitudinal bars (33, 35) and the central longitudinal bar (34) extend to the height of the upper face (5a) of the supporting surface to form an aerating pocket (16) which is approximately box-shaped above each recess (6).
9. Cooler grate as claimed in claim 6, characterised in that of the two outer longitudinal bars (33, 35) only one outer longitudinal bar adjacent to one outer long side of the cooler grate also extends to the height of the upper face (5a) of the supporting surface.
10. Cooler grate as claimed in claim 1, characterised in that each aeration cap (9, 9' in Figures 7 and 9) has a substantially flat upper face which lies flush with the upper face of the supporting surface (5, 5' in Figures 7 and 9).
11. Cooler grate as claimed in claim 1, characterised in that the annular gaps which form the cooling gas openings (10, 10') have an elongated rectangular shape which is closed in the top view of the supporting surface (5, 5'), the long sides of the rectangle running substantially parallel to the direction (1) of conveying the material to be cooled.
12. Cooler grate as claimed in claim 1, characterised in that at least two recesses (6, 6') each having an appertaining aeration cap (9, 9') are provided in the supporting surface (5, 5') of each grate plate (2, 2').
13. Cooler grate as claimed in claim 2, in which the grate plate supports (3, 3') are constructed as hollow bodies for the delivery of the cooling gas, characterised in that the grate plates (2, 2') are constructed and fixed on the grate plate supports (3, 3') in such a way that the cooling gas (4) can flow freely at least onto the base (7, 7') of the recesses (6, 6') and the aeration caps (9, 9') arranged above them.
14. Cooler grate as claimed in claim 13, characterised in that the internal width of the cooling gas inlet slots (11, 11') is chosen so that approximately equal quantities of cooling gas can be delivered to the grate plates (2, 2') which are supplied with cooling gas through a grate plate support section.
15. Cooler grate as claimed in claim 13, characterised in that the cooling gas openings (10) in the form of annular gaps are aligned substantially perpendicular to the upper face (5a) of the supporting surfaces (5).
16. Cooler grate as claimed in claim 13, characterised in that the longitudinal sections of the cooling gas openings (10') in the form of annular gaps which run in the direction (1) of conveying the material to be cooled are inclined with respect to the vertical, so that - viewed in the cross-section of the cooler grate and starting in each case from the vertical longitudinal central plane (17) - the longitudinal sections of the cooling gas openings (10') of the grate plates (2') fixed on both transverse halves of the cooler grate are each inclined with respect to the outer longitudinal side of the cooler grate lying nearest.

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