US3759369A - Traveling grate - Google Patents

Abstract

A plurality of hingedly connected members, each including a support plate for providing a substantially continuous transport surface in the upper section of the grate to support material conveyed by the grate, have pocket-like recesses on their inner sides. Each support plate in the vicinity of its front and rear ends is hingedly connected with the adjacent support plates so that the support plates form a substantially continuous peripheral surface throughout the extent of the grate.

Description

United States Patent 1191 Vering et a1.

[ 1 Sept. 18, 1973 TRAVELING GRATE [75] lnventors: Antonius Vering, Vorhelm; Alois Kluger, Neubeckum; Karl Eiring, Oelde, all of Germany [73] Assignee: Polysius AG, Neubeckum, Germany 221 Filed: Feb. 11, 1972 211 Appl.No.:2 25,587

[30] Foreign Application Priority Data Mar. 2, 1971 Germany P 21 09 948.9

[52] U.S. Cl. 198/140, 198/195 [51] Int. Cl. B651; 17/16 [58] Field of Search 198/140, 141, 142, 198/143, 195,44; 74/255 [56] References Cited UNITED STATES PATENTS 2,597,064 5/1952 Charles et a1 198/44 1,971,553 8/1934 Fisk 848,236 3/1907 Ginaca 198/195 Berger 74/255 565,199 8/1896 3,034,638 5/1962 Franz 516,702 3/1894 Franklin.....

2,112,911 4/1938 J0hns0n..... 1,100,148 6/1914 Perry 74/255 FOREIGN PATENTS OR APPLICATIONS 241,654 3/1910 Germany 198/142 Primary Examiner-Richard E. Aegerter Assistant Examiner-Joseph E. Va'lenza [57] ABSTRACT A plurality of hingedly connected members, each including a support plate for providing a substantially continuous transport surface in the upper section of the grate to support material conveyed by the grate, have pocket-like recesses on their inner sides. Each support plate in the vicinity of its front and rear ends is hingedly connected with the adjacent support plates so that the support plates form a substantially continuous peripheral surface throughout the extent of the grate.

4 Claims, 8 Drawing Figures Patented Sept. 18, 1973 3,759,369

2 Sheets-Sheet 1 Patented Sept. 18, 1973 3,759,369

2 Sheets-Sheet 2 Fig. 5

I TRAVELING GRATE BACKGROUND OF THE INVENTION This invention relates to a traveling grate, comprising a plurality of hingedly connected members which by means of support plates form in the upper section of the grate a substantially continuous transport surface for the material conveyed by the grate.

In various branches of industry, for example in cement and phosphate manufacture, traveling grates are used to convey material (such as pellets, granulated cement, etc.) through treatment zones wherein heat exchange take place between the material and a gas.

Previously known traveling grates consist in general of at least two endless chains running in parallel and connected together by grate bolts on which are disposed freely rotatable spacer bushes. Each spacer bush is affixed to one end of a support plate so that while it is in the'upper section of the grate the said plate forms a transport surface for the material being treated which is outwardly almost closed, in that the free end of the support plate is supported on the next bush following. With reversal of the grate, the support plates tilt downwards at their free ends, resulting in considerable gaps between successive grate bolts or spacer bushes. The fine material falling through the upper section of the grate is supposed to pass through these gaps so as to be withdrawn from the interior of the housing. In practice, however, the support plates frequently become severely damaged, and cannot be repaired or replaced during periods of normal operation. Hence part of the coarser material also drops down and is removed together with the fine material. While the fine material falling through the slots in the grate is often not fed back to the grate, this is generally necessary from the process aspect for the coarser material, so that extensive equipment has to be installed below the grate for catching and if necessary sorting and conveying away the dropped material.

In the case of treated material with a relatively high proportion of fine material, the further disadvantage arises that for various reasons, e.g., the method of driving the grate, or high gas pressures in some of the treatment zones, the support plates in the grate, hinged at one side, may become tilted, so that an undesirably large proportion of the treated material falls through the grate.

SUMMARY OFTHE INVENTION The object of the invention is therefore to provide a traveling grate of the type described wherein without expensive auxiliary equipment, at least the coarser fraction falling through damaged support plates, and possibly the greater part of the fine material falling through are fed back to the inlet end of the traveling grate.

According to the invention this object is achieved in that the grate members have pocket-like recesses open towards the interior of the grate, and the support plates in the vicinity of their front and rear ends are hingedly connected with the adjacent support plates in such a manner that said support plates also form a substantially closed peripheral surface in the area outside the upper section of the grate.

Because 'of the construction of the grate provided by the invention, the material'dropping through the upper section of the grateis captured and conveyedby the members running below in the opposite direction, i.e., towards the entry end. In the area where the grate is re versed to form the upper section, the material which has dropped into the pocket-shaped recesses drops downwards, and can be readily recovered and fed back to the grate. Since with this construction the support plates form a substantially closed outer surface in all peripheral areas of the grate, i.e., are not hinged at one side as in the known grates, even in treating material with a very high proportion of fines the risk of an undesirably great amount of fine material falling through gaps caused by lifting of the support plates is avoided.

The material which falls out of the pocket-shaped recesses when the grate is reversed can be captured in a simple manner if a receiving container is disposed below the region wherein the rising grate is deflected into a substantially horizontal path of movement, said container having one wall which terminates a small distance from the inner periphery of the grate. The falling material captured in this manner can then be fed back to the grate by means of a transverse conveyor leading from the receiving container.

According to a further aspect of the invention it is advantageous if each support plate, made slightly arcuate in the longitudinal direction, has its one end bent inwards by about in relation to the transport surface, about the axis of the joint, and the adjacent end of the following support plate is in sliding contact with the resultant arcuate surface. This construction of the sup port plate provides effective stiffening of the member and results in easier emptying of the pocket-shaped recess. This arrangement of successiveumembers in accordance with the invention also provides agrate which, in the said areas at least, forms a relatively sealed transport surface. In thiscase it is desirable also that the contacting surfaces at the adjacent ends of the support plates in successive members be provided with wear inserts made from material with a low coefficient of friction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a'purely schematic elevation of a traveling grate in accordance with the invention;

FIGS. 2 and 3 are fragmentary elevations (II and III) of the traveling grate shown in FIG. 1;

FIG. '4 is a plan view of the two hingedly connected members shown in FIG. 3;

FIG. 5 is an elevation of the two members of a modi DESCRIPTION OF T l-IE PREFERRED EMBODIMENTS The traveling grate 1 as provided by the invention and shown in FIG. 1 comprises a plurality of members hingedly connected together. The: upper section .2 of the traveling grate 1 forms a transport surface for material being treated (pellets, cement granulate or the like), which is to be fed through one or more treatment zones, for instance for preheating, firing and/or cooling. The largely closed transport surface is formed by support plates on the hingedly connected members. The traveling grate moves in the direction of arrow 3 and is deflected around an axis A at its inlet end, around an axis A; at its outlet end, and around axes A, and A, in its lower section. The grate members 4 are open towards the grate interior, and have pocketshaped recesses 5,5 (see FIGS. 2 and 3). The support plates are made slightly bowed in the longitudinal direction of the grate, and adjacent their front and rear ends are hingedly connected to the adjacent support plates so that a substantially continuous peripheral surface is formed both in the upper section 2 of grate 1 and also in the area outside the upper section of the grate. Thus when material falls through gaps between adjacent members or through damaged members, it can be captured on the inside of the part of the grate which is traveling beneath. The material .enters the pocket- shaped recesses 5, 5 in the members 4 and is transported thereby to the inlet end of the grate. In the area of axis A, the rising grate section is deflected into the upper section, which in this embodiment is generally horizontal. During this deflection the recesses 5,5

which previously (in the lower section of grate) were open substantially upwards are turned so that their apertures point approximately or completely downwards, and hence the entrained material can fall downward (see FIG. 2).

In order to be able to catch the falling material, a receiving container 7 is disposed in the interior of grate 1 below its reversal point (deflection axis A The one wall 7a of this receiving container ends at a slight distance from the inner periphery of the grate, with the end of the wall 70 matched to the curvature of the grate somewhat in the manner of a tongue. The falling material caught by the receiving container 7 can then be removed from the grate interior, for instance by the transverse conveyor 8, and returned to the upper section of the grate.

The transverse conveyor 8 can also be replaced by inclined base sheets in the nature of a chute below the receiving container 7, which remove the deposited material from the interior of grate 1.

As seen especially from FIGS. 3 and 4, each member 4 -has a transverse rib 9 extending generally transversely to the direction of movement of the grate and perpendicular to the transport surface formed by the upper section. On each side of transverse rib 9 are provided stiffening ribs running in the longitudinal direction of the member. The ends of the stiffening ribs 10, 10a,

I which are disposed on the side 9a of transverse rib 9,

are fixedly attached to spacer bushes 11, 11a. On the side 9b of transverse rib 9 the stiffening rib l2 is used only to stiffen the member 4. Support brackets 13, 13a are secured to transverse rib-9 and at their ends jointly support a further spacing bush 14. The spacer bushes 11,11a are relatively short and at their outer ends are flush with the side'edges of member 4. Between the facing inner ends of the spacer bushes 11, 11a is a gap corresponding in general to the length of spacer bush 14.

'The spacer bushes 11,11a and 14 all have at least the same internal diameter, and act as coupling elements for successive grate members which are to be hingedly joined together. A grate bar 15 is inserted through the interengaged and aligned bushes 11,11a and 14 in order to connect hingedly the successive members 4 (see FIG. 4).

At its end 6a which carries the bushes 11,11a, the support plate 6 of member 4 is bent inwards through about 90 from the conveyor surface, about the axis of the bushes 11,1la which in this area forms the pivot axis of the member. At the opposite end the slightly arcuate support plate 6 projects generally freely (see FIG. 3). As seen especially from FIGS. 2 and 3, the adjacent plate end of the following members in sliding contact with the arcuate surface formed at the end 60. Consequently when the traveling grate l is deflected over one of the axes A -A the rear support plate end 6b of one member slides along the end 6a of the adjacent member. The successive support plates 6 therefore form a relatively sealed transport surface. In order to keep friction and hence wear as low as possible at these points, wear inserts 6a, 6b made from material with a low coefficient of friction can be provided at the contacting surfaces of adjacent support plate ends.

The grate members in accordance with the invention and as particularly described in relation to FIGS. 3 and 4 form a stable embodiment, suitable especially for very robust traveling grates.

FIGS. 5-8 show further embodiments of grate members in accordance with the invention. FIG. 5 shows a side view of two intercoupled members. This side view applies generally to all of the three embodiments shown in FIGS. 6-8. I

The embodiment shown in FIG. 6 of a member 16 in accordance with the invention relates to a relatively light grate construction. The grate member 16 consists in general of a support plate 17 corresponding in general shape and construction to the support plate 6 in the first embodiment, with a longitudinally extending sifi'ening rib 18. This stiffening rib 18 is placed at about the middle of plate 16, and at its end 18a which is at the end of support plate 16 provided with an arcuate surface, there is a claw-like structure 22. The claw end is provided with a bore 19 whose axis coincides with the axis of curvature of the arcuate surface of this support plate 17 and thus with the pivoting axis for this member 16. The opposite and generally straight end 18b of the stiffening rib 18 projects beyond the support plate 17, and is provided with a bore 20 whose axis coincides with the pivotal axis of the adjacent grate member. In order to connect hingedly together two grate members 16 which follow each other longitudinally, the straight end-18b of the stiffening rib 18 of the preceding member is inserted in the claw-like structure 22 at the end 18a of the stiffening rib 18 of the following member, so that holes 19,20 are aligned and can be hingedly connected together by means of a grate bar 21. To ensure that the end 18b, which projects beyond its corresponding support plate 17, is freely pivotable within wide limits, the arcuately shaped end 22 of each support plate 17 has a corresponding slot, of width such that the end 18b can slide to and fro therein.

In the embodiment of a grate member 23 shown in FIG. 7, the stiflening rib 18 in the previous embodiment is replaced by two stiffening'ribs 24 and 25 extending generally along the side edges of support plate 17'. While the ends 24a and 25a of the stiffening ribs 24,25 are inwardly cranked in the area of the arcuately upturned end of the support plate, by about the thickness of a stiffening rib, the opposite straight ends 24b and 25b can project beyond the other support plate end as in the preceding example. The ends of the stiffening ribs 24 and 25 are again provided with bores, so that succeeding and interconnected grate members 23 can be hingedly coupled together by means of a grate bar Finally FIG. 8 shows an embodiment which is only slightly varied from the example shown in FIG. 7. The main feature of this embodiment is that two slightly differing types of member are provided. The members 27,28 are however made somewhat more simply than in the preceding example, due to the generally straight stiffening ribs 29, 30 and 31, 32, which are easier to manufacture. The stiffening ribs 29,30 of the one member 27 are generally flush with the side edges of the support plate 17". The stiffening ribs 31,32 of the next following grate member 28 are inwardly displaced by about the thickness of a stiffening rib, so that they lie against the insides of the ends of the adjacent stiffening ribs 29,30 which cooperate with them in hinge coupling engagement. The hinge joint between two grate members 27,28 in longitudinal sequence can also be formed by means of a grate bar 26.

We claim:

1. An endless traveling grate for transporting material through a heat exchange zone, having a substantially horizontal upper run, a descending section, a lower run and a rising section, wherein the improvement comprises a series of support plates each comprising a hinge, each plate having at one end an arcuate portion the axis of which is the axis of the hinge, having a portion at its other end in sliding contact with such arcuate portion of the succeeding support plate, and

having, rigid therewith, at least one arm which extends beyond said other end and is pivotally connected to the hinge of such succeeding support plate, the inner sides of the support plates forming open, pocket-like recesses between adjacent such arcuate portions, a receiving container which has a wall that terminates close to the inside of the rising section of the grate, for receiving material that has fallen from the recesses of the upper run of the grate and a transversely extending conveyor positioned below said container, for receiving and removing material from the receiving container.

2. A traveling grate according to claim 1 wherein the contacting portions of the adjacent support plates are provided with wear inserts of material having a low coefficient of friction.

3. A traveling grate according to claim 1 wherein each support plate has, on its inner surface, a transverse rib, and at least one longitudinal stiffening rib having attached at its end a spacing bush forming part of said hinge.

4. A traveling grate according to claim 3 wherein at least one rib carries an arm which is pivotally connected to the hinge of the succeeding support plate.

Claims (4)

1. An endless traveling grate for transporting material through a heat exchange zone, having a substantially horizontal upper run, a descenDing section, a lower run and a rising section, wherein the improvement comprises a series of support plates each comprising a hinge, each plate having at one end an arcuate portion the axis of which is the axis of the hinge, having a portion at its other end in sliding contact with such arcuate portion of the succeeding support plate, and having, rigid therewith, at least one arm which extends beyond said other end and is pivotally connected to the hinge of such succeeding support plate, the inner sides of the support plates forming open, pocket-like recesses between adjacent such arcuate portions, a receiving container which has a wall that terminates close to the inside of the rising section of the grate, for receiving material that has fallen from the recesses of the upper run of the grate and a transversely extending conveyor positioned below said container, for receiving and removing material from the receiving container.

2. A traveling grate according to claim 1 wherein the contacting portions of the adjacent support plates are provided with wear inserts of material having a low coefficient of friction.

3. A traveling grate according to claim 1 wherein each support plate has, on its inner surface, a transverse rib, and at least one longitudinal stiffening rib having attached at its end a spacing bush forming part of said hinge.

4. A traveling grate according to claim 3 wherein at least one rib carries an arm which is pivotally connected to the hinge of the succeeding support plate.

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