Grid bar, grid bar arrangement, pallet car of a sintering or pelletizing machine and sintering or pelletizing machine
Patent Information
- Application Number
- BR112022022301
- Authority / Receiving Office
- BR · BR
- Patent Type
- Patents
- Current Assignee / Owner
- Publication Date
- 2026-09-01
Smart Images
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Abstract
Description
1 / 19 TECHNICAL REPORT “GRID BAR, GRID BAR ARRANGEMENT, PALLET CART OF A SINTERING OR PELLETIZING MACHINE AND SINTERING OR PELLETIZING MACHINE” FIELD OF THE ART
[001] The present invention relates generally to a device used in a sintering or pelletizing machine, and more particularly to a grid bar for mounting in arrangements of adjacent grid bars on a pallet carriage of a sintering or pelletizing machine. BACKGROUND OF THE INVENTION
[002] In sintering or pelletizing machines, bulk material to be treated, for example, iron ore, is loaded onto a conveyor grid comprising an endless chain of pallet cars. The pallet cars filled with the bulk material are driven through various treatment stations to thermally treat the material, which is then discharged from the machine as a thermally treated product.
[003] After the treatment stations, the pallet cars are turned over to discharge the thermally treated product located on the grates by gravity, and the cars are guided upside down back to the beginning of the treatment stations of the sintering or pelletizing machine, where they are turned over again, ready to receive bulk material. The sintering or pelletizing machine thus operates in a cycle like an endless grate car chain.
[004] The top of pallet trucks comprises a grid onto which the bulk material is loaded. During heat treatment, heating of the bulk material is achieved by blowing a stream of heated gas both upwards and downwards through the bulk material and the grid of the pallet truck. The grid, therefore, generally comprises a plurality of grid bars separated by gaps to allow gas flow through it. The grid bars are arranged Petition 870220101418, dated 03 / 11 / 2022, pp. 71 / 99 2 / 19 parallel to each other in rows and columns so as to cover the entire loading surface of the pallet truck. A grid bar typically comprises a main support beam to receive the bulk material on it. The main beam additionally comprises connection means, usually in the form of a tongue and groove design, to attach the grid bar to a frame element of the pallet truck.
[005] Individual grid bars are generally arranged loosely in the pallet car, side by side, so as to maintain a degree of movement. This arrangement allows the grid to clean itself automatically. In fact, the movement of the grid bars relative to each other when the pallet cars are turned upside down allows bulk material trapped between two neighboring grid bars to loosen and fall out of the grid. Means of connecting the grid bars to the pallet cars are configured in a tongue and groove design at each end of the grid bar, to prevent the grid bars from falling out when the pallet cars are turned over.
[006] Due to the high thermal variations within the sintering or pelletizing machine, the connection between the grate bars and the pallet car usually includes an expansion space, in all three directions, allowing for thermal expansion of the grate bars.
[007] Because pallet trucks are subject to very harsh thermal conditions inside the machine, pallet trucks suffer substantial mechanical wear, particularly caused by the highly abrasive surface of the bulk material. As a result, grid bars need to be replaced regularly.
[008] Typical signs of wear on grid bars show a decreasing volume of the top master beam due to material impact combined with high temperature and airflow. The grid bar eventually loses its initial shape and the predetermined gap between the grid bars is no longer maintained.
[009] In use, sinter particles or pellets become trapped in the gaps between grating bars and tend to propel a grating bar toward a bar Petition 870220101418, dated 03 / 11 / 2022, p. 72 / 99 3 / 19 of adjacent grid. The grid bars thus lose their parallel positioning and become inclined relative to each other. As a consequence, the gaps between the grid bars comprise wider and narrower areas. In the wider areas, larger and more numerous particles become trapped, thus increasing the abrasion phenomenon and reducing the lifespan of the grid bars and the pallet truck in general. In narrower areas, there is no remaining space to allow for thermal expansion of the grid bar, thus reducing its robustness and causing material damage. Additionally, the negative effect of bulk material falling through the gaps between grid bars can impact downstream equipment, such as air boxes, ducts, fans, and seals.
[010] When the pallet car is turned upside down, loosely connected grid bars move vertically relative to the car. Then, at the start of the line, the pallet car is turned back to its regular position with the grid bars falling into their functional places. However, bulk particles or any spillage trapped in spaces between the grid bars can hinder the correct vertical positioning of the grid bars. Some grid bars may not seat properly and remain protruding from the otherwise generally flat surface of the grid car. The irregular top surface thus formed on the pallet car increases localized wear due to abrasive effects. Vertically misaligned grid bars also interfere with the cleaning process of the top surface of the pallet car arrangement.
[011] Although the loose connection between the grid bars and the pallet car allows for easy replacement of the grid bars, these operations are costly and time-consuming. Therefore, there is a need to improve the durability of the grid bars.
[012] Solutions are known in the art to reduce wear on grid bars. For example, document no. US 1,704,027 discloses a grid for Petition 870220101418, dated 03 / 11 / 2022, p. 73 / 99 4 / 19 Sintering Plants. The grid comprises a plurality of grid bars connected to a grid cart. In this example, the grid bars are fitted with transverse spacers in their transverse direction in order to maintain a gap between adjacent grid bars. Grid bars are connected to each other by a longitudinal projecting end. This overlapping end limits the movement of the bars during the turning of the pallet cart in order to have better weight distribution and prevent the grid bars from prematurely rocking the pallet cart until it has been rotated to a predetermined position. Once the predetermined rotational position has passed, the grid bars will move with considerable force to more effectively break and dislodge any material that may obstruct the spaces between grid bars.
[013] This solution limits the obstruction of the gaps between the grid bars and attempts to prevent height differences when the pallet car returns to its original position. However, there is no solution to prevent lateral or longitudinal misalignment of the grid bars or to delay wear on the grid bars.
[014] Another solution is suggested in document no. US 2,949,289 A, which discloses a grid bar for a sintering or pelletizing machine, wherein the grid bar automatically clears itself of material lodged between the grid and the pallet car frame. The end of the grid bar comprises a wedge shape to propel sinter particles. As the pallet car is turned to its original position, the grid bars move to their support element on the pallet car, propelling any particles below the end of the grid bars to ensure that the grid bars do not become stuck in a higher vertical position.
[015] In the last solution, there are again ways to improve the vertical positioning of the grid bar, but there is a risk of horizontal misalignment causing increased wear on the grid bars. OBJECTIVE OF THE INVENTION
[016] Therefore, it is desirable to provide a solution to improve durability. Petition 870220101418, dated 03 / 11 / 2022, p. 74 / 99 5 / 19 of a grid bar, in particular, to reduce increased wear caused by grid bar misalignments on a pallet truck. GENERAL DESCRIPTION OF THE INVENTION
[017] The invention overcomes the shortcomings and disadvantages discussed above by providing a grid bar for a pallet car of a sintering or pelletizing machine. The grid bar is preferably mounted in arrangements of adjacent grid bars on the pallet car. The grid bar comprises an elongated main beam extending in a longitudinal direction from a horizontal plane, with an intermediate section between two opposite side sections.
[018] The main beam has a generally rectangular cross-section with a support surface to receive bulk material on it, an opposite base surface, and peripheral surfaces to contact the adjacent grid bars. The main beam additionally comprises two legs to vertically attach the grid bar to the pallet cart. Each leg may have a hook shape with a vertical branch essentially perpendicular to the bottom surface, and a horizontal branch essentially parallel to the bottom surface and extending outwards.
[019] According to the invention, the end sections of the main beam comprise a first interlocking means, the latter being shaped and arranged so that the first interlocking means cooperates with the first interlocking means of grid bars of a neighboring row of grid bars; thus limiting relative translations of two neighboring grid bars in at least one vertical and one horizontal orientation. The first interlocking means has a triangular cross-section in a horizontal plane.
[020] Due to the triangular shape of the first interlocking means, the end sections of the grid bars of one row of grid bars engage with the end sections of the grid bars of a neighboring row of grid bars. This not only limits the individual grid bars in their Petition 870220101418, dated 03 / 11 / 2022, pp. 75 / 99 6 / 19 movement in the longitudinal and transverse direction of the grid bar, but also in its rotational movement. In fact, the grid bars are prevented from tilting or jamming. In this way, the predefined gap between neighboring grid bars is essentially maintained. The undesirably increasing gap between neighboring grid bars can be avoided.
[021] In the context of the invention, the term orientation is used to refer to an overall orientation that can be represented by a line in three-dimensional space. The term direction will then refer to one of the two directions possibly pointed to by an orientation.
[022] In the context of the invention, the horizontal plane is parallel to the surface formed by the arrangement of grid bars on which bulk material is received, and therefore parallel to the plane of the pallet carriage of a sintering or pelletizing machine. A horizontal direction is thus comprised within the horizontal plane and includes the longitudinal and transverse directions.
[023] The first interlocking means preferably limits the translation of the grate bar in both directions of the horizontal orientation. The position of the first interlocking means at the end section of the grate bar allows a gap to be provided between two adjacent grate bars in the intermediate section. This gap forms a gas passage allowing a gas stream to flow through the grate.
[024] Preferably, the triangular cross-section of the first interlocking means has an apex, which is located on a medial line between two lateral surfaces of the main beam. This medial line is parallel to the two lateral surfaces and arranged to be halfway between the two lateral surfaces. The medial line extends beyond the main beam in the longitudinal direction. With the apex located on this medial line, the shape of the triangular cross-section is that of an equilateral or isosceles triangle. Thus, the first interlocking means is a first V-shaped interlocking element. However, the provision of a first interlocking means in which the apex is not located is not excluded. Petition 870220101418, dated 03 / 11 / 2022, pp. 76 / 99 7 / 19 such median line, thus providing a first interlocking means that has a shape corresponding to an acute triangle or even a right triangle. The opposite end of the neighboring grid bar then has its first interlocking element of a complementary shape.
[025] Preferably, the peripheral surfaces of the intermediate section of the grid bar respectively comprise at least one spacer extending in a transverse direction. Although it is not excluded to provide more than one spacer on the longitudinal side surfaces, the grid bars are, however, advantageously provided with a single spacer in the center of the intermediate section.
[026] The spacers are arranged so that two adjacent grid bar spacers come into contact with each other, thus defining the distance between the main beams, i.e., the gap between grid bars through which gas is blown. The spacers are advantageously positioned and sized to define, in use, a gap between adjacent main beams that forms a gas passage for an incoming gas flow. Such a spacer thus defines a constant gap between two adjacent grid bars, so as to maintain airflow through a grid bar arrangement while preventing material particles from falling through the grid. The spacer is preferably arranged in an upper region of the main beam due to the fact that this section is exposed to greater wear. During the lifespan of the grid bar, this upper part and the spacer will be reduced in width.However, due to the overlapping of the end sections of the grate bars between adjacent rows, the grate bars can be readjusted to maintain the desired gap through which gas is blown.
[027] The spacer may be of any suitable shape. Preferably, however, the spacer has a shape that narrows in the direction of the incoming gas flow. Such a spacer may be, for example, triangular or semicircular, with its pointed or rounded side facing upwards for machines in which gas is blown through the grille bars from above or downwards for machines in which Petition 870220101418, dated 03 / 11 / 2022, pp. 77 / 99 8 / 19 gas is blown through the grill bars from underneath.
[028] Additional interlocking means may be provided to secure a grid bar relative to an adjacent grid bar. Such additional interlocking means may comprise one or more interlocking elements. When two adjacent grid bars move vertically, for example, due to the turning of the pallet cart, the overlapping of the interlocking means ensures that there is no vertical misalignment of the grid bars. As they overlap in at least one vertical and one horizontal orientation, most grid bar misalignments are avoided.
[029] Preferably, the interlocking means is configured to overlap with an interlocking means of a neighboring grid bar in the longitudinal orientation of the row grid bar.
[030] According to one embodiment of the invention, the grid bar is provided with a second interlocking means, which may comprise a first protrusion and a corresponding second protrusion arranged to overlap a first protrusion of a neighboring grid bar. The first and second protrusions project onto the end sections of the main beam in a transverse direction. The first and second protrusions are positioned in such a way that, when two grid bars are positioned in a grid, one side of the first protrusion of one grid bar faces one side of the second protrusion of the other grid bar. The first and second protrusions thus form a contiguity with each other in the longitudinal direction of the grid bar, thereby limiting movement of the grid bars in the longitudinal direction.
[031] The first and second protrusions may be rectangular in cross-section. Alternatively, the first and second protrusions may be triangular in cross-section. In the latter case, the protrusions may be arranged so as to limit not only the movement of the grid bars in the longitudinal direction, but also in the vertical direction. Petition 870220101418, dated 03 / 11 / 2022, pp. 78 / 99 9 / 19
[032] According to one embodiment of the invention, the grate bar is provided with a third interlocking means on the longitudinal sides of the grate bar legs.
[033] In one embodiment, the third interlocking means may comprise an upper edge on one side of a leg and a lower edge on the other side of the leg; wherein the upper and lower edges are dimensioned and positioned in a staggered arrangement so that, in use, an upper edge of a grid bar cooperating with a lower edge of a neighboring grid bar forms a contiguity in a vertical height direction of the grid bar. The upper and lower edges are preferably arranged in the horizontal branching of the leg.
[034] In another embodiment, the third interlocking means may comprise a first U-shaped flange disposed on one side of the grid bar and a second U-shaped flange disposed on the other side of the grid bar. Each U-shaped flange extends through the horizontal branch of the leg, through the vertical branch of the leg, and through a final portion of the main beam. The second U-shaped flange has a shape corresponding to that of the first U-shaped flange, but offset so that, in use, a first U-shaped flange of a grid bar cooperates with a second U-shaped flange of a neighboring grid bar to form a contiguity in a vertical height direction and in the longitudinal direction of the grid bar.
[035] Preferably, the upper surface of the main beam has a concave or convex shape depending on which type of machine the grid bar is used on.
[036] In fact, in pelletizing machines, it has been found that most of the wear occurs at the end sections of the main beam. Grate bars for use in pelletizing machines are therefore advantageously provided with a convex upper surface to increase the amount of bulk material at the end sections of the main beam, thus better protecting the latter against Petition 870220101418, dated 03 / 11 / 2022, pp. 79 / 99 10 / 19 wear.
[037] In sinter machines, on the other hand, most of the wear occurs in the intermediate section of the main beam. Grate bars for use in sinter machines are therefore advantageously provided with a concave upper surface to increase the amount of bulk material in the center of the main beam, thus better protecting the intermediate section against wear.
[038] The cross-section of the main beam may, in its intermediate section, be narrowing towards the lower surface. Such a narrowing intermediate section not only reduces the weight of the grate bar, but also helps to guide the gas flow to or from the region under the grate bar.
[039] The grate bar according to the present invention may additionally comprise a stiffening rib disposed on the lower surface of the main beam, extending between the two legs, and preferably extending downwards on the inner sides of the legs. Such a stiffening rib may increase the robustness of the grate bar and thus also extend its service life. A recess may be disposed in the center of the intermediate section to further reduce the weight of the grate bar.
[040] According to another aspect, the invention relates to an arrangement of grid bars according to claim 15.
[041] According to yet another aspect, the invention relates to a pallet car of a sintering or pelletizing machine, wherein the pallet car comprises a grid with a plurality of arrangements of adjacent grid bars creating a flat surface to receive bulk material thereon, wherein the grid bars are grid bars as described above. BRIEF DESCRIPTION OF THE DRAWINGS
[042] Further details of the present invention will become apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a first modality. Petition 870220101418, dated 03 / 11 / 2022, pp. 80 / 99 11 / 19 preferred version of a grid bar according to the invention; Figure 2 is a side view of the grid bar from Figure 1; Figure 3 is a top view of the grid bar from Figure 1; Figure 4 is a top view of an arrangement of the grid bars from Figure 1; Figure 5 is a side view of a second preferred embodiment of a grid bar according to the invention; and Figure 6 is a side view of a third preferred embodiment of a grid bar according to the invention. DESCRIPTION OF PREFERRED OPTIONS
[043] Preferred embodiments showing non-limiting examples of the grid bar according to the invention will now be described with reference to Figures 1 to 6. It is understood that features not described in detail in one embodiment may be considered similar to the feature in prior embodiments. Furthermore, in order not to overload the Figures, some numerical references denoting identical features have not been repeated in all Figures.
[044] In the description below, the terms top, bottom, above, below, vertical, horizontal will be used in reference to the direction in the Figures to facilitate explanation. The longitudinal (horizontal) direction L, the transverse (horizontal) direction T, and the height (vertical) direction H are indicated in the Figures.
[045] The grid bar is adapted to be mounted in arrangements of adjacent grid bars on a pallet car frame element, not shown, and used in a sintering or pelletizing machine. In the following description of the grid bar, the interaction between neighboring grid bars in an arrangement will be mentioned to clarify the functions of the features.
[046] Figures 1 to 3 show a grid bar 10 according to one embodiment, the grid bar 10 having an elongated main beam 12 extending in a longitudinal direction from a horizontal plane, and legs 14 fixed to the main beam 12 for vertically attaching the bar 10 to a carriage frame. Petition 870220101418, dated 03 / 11 / 2022, pp. 81 / 99 12 / 19 pallets (not shown). The grid bar 10 is virtually divided into three sections, a first end section 16, a second end section 18 opposite the first end section 16 and an intermediate section 20 between the two end sections 16, 18.
[047] The main beam 12 extends from the first end section 16, through the intermediate section 20, to the second end section 18 and has a generally rectangular cross-section. It comprises an upper surface 22 for receiving bulk material thereon, and an opposite lower surface 24 which, in use, is in contact with the pallet car frame. The main beam 12 also comprises peripheral surfaces that join the upper and lower surfaces 22, 24. The peripheral surfaces are, in use, oriented towards the adjacent grid bars. The peripheral surfaces comprise two longitudinal side surfaces 28 and, at each end of the end sections 16, 18, two transverse end surfaces 30.
[048] In a grid bar arrangement, the peripheral side surfaces 28, particularly in the intermediate section of the main beam, define a fluid passage for a gas flow between two adjacent grid bars; that is, through the grid.
[049] The legs 14 are fixed to the lower surface 24 at each end section 16, 18, and have a hook shape with a vertical branch 34 essentially perpendicular to the lower surface 24, and a horizontal branch 36 essentially parallel to the lower surface 24 and extending outwards.
[050] In use, grid bar 10 is mounted on the pallet car, with a pallet car frame element interposed between the bottom surface 24 on each end section 16, 18 and the horizontal branch 36 of the leg 14 of grid bar 10, thus limiting the translation of grid bar 10 in a vertical direction.
[051] The versed element will understand that, when the pallet truck enters the sintering or pelletizing machine and transports bulk material through Petition 870220101418, dated 03 / 11 / 2022, p. 82 / 99 13 / 19 heat treatment stations, the grid bar is supported on the pallet car with its lower surface at the end sections resting on the pallet car frame. When the pallet car is turned over, the grid bar lifts the frame through gravity. The grid bar is prevented from falling off the pallet car by means of locking bars that engage the horizontal branches 36 of the legs 14.
[052] As shown in Figures 1 to 3, the end sections 16, 18 of the main beam 12 comprise the first interlocking means 38 configured to be in overlapping contact with the first interlocking means 38 of a neighboring grid bar, thus limiting relative translations of two neighboring grid bars in any horizontal direction. In fact, the grid bar is then prevented from moving in a longitudinal direction L and in a transverse direction T. The first interlocking means 38 also limits the rotational movement of the grid bars 10 in the plane of the arrangement, i.e., the horizontal plane.
[053] Figure 4 shows a top view of an arrangement of grid bars 10 as arranged in a pallet car. This shows a first row 40 of grid bars 10 and a second row 42 of grid bars 10. The transverse end surfaces 30 of the second end section 18 of the grid bars 10 of the first row 40 engage with the transverse end surfaces 30 of the first end section 16 of the grid bars 10 of the second row 42. A gap 44 is provided between neighboring grid bars 10 to allow thermal expansion of the grid bars 10 in a longitudinal and transverse direction L, T.
[054] In the embodiment shown in Figure 4 (also Figures 1-3), the first interlocking elements 38 have a triangular shape, with the apex 48 of the triangle being located on the medial line M between the two parallel lateral surfaces 28, thus forming an equilateral or isosceles triangle (first interlocking element in V shape). The grid bars 10 of two adjacent rows 40, 42 of grid bars are thus arranged as shown in Figure 4, Petition 870220101418, dated 03 / 11 / 2022, pp. 83 / 99 14 / 19 in a staggered configuration. It will be understood, however, that the first interlocking elements 38 may also have a triangular shape representing an acute triangle or even a right triangle. The opposite end of the neighboring grid bar 10 evidently requires that its first interlocking element be of a complementary shape.
[055] Returning to Figures 1 to 3, the grid bar 10 further comprises a spacer 50 disposed on each of the longitudinal side surfaces 28 of the main beam 12. The spacers 50 are provided at the center of the intermediate section 20 and extend in a transverse direction T from the grid bar 10. The spacers 50 are arranged so that two spacers 50 of adjacent grid bars 10 come into contact with each other, thus defining the distance between the main beams 12, i.e., the gas passage 52 between grid bars through which the gas is blown.
[056] The spacer 50 can be of any suitable shape, such as, for example, rectangular, triangular, circular or, as shown in Figures 1 to 3, semicircular. The rounded edge of the spacer 50 faces the incoming gas stream, offering less resistance to the gas stream blown through the grate bars. In machines where gas is blown through the grate bars from above, the rounded edge of the spacer 50 faces upwards as shown in Figures 1 to 3. In machines where gas is blown through the grate bars from below, the rounded edge of the spacer 50 will obviously face downwards.
[057] Preferably, each side of the longitudinal lateral surface 28 comprises a single spacer 50. However, the provision of more than one spacer on the longitudinal lateral surfaces 28 is not excluded.
[058] Spacers 50 enhance the parallelism of two adjacent grid bars and ensure that the gas passage 52 (as seen in Figure 4) defined by the gap between the main beams 12, remains of essentially constant width. Spacers 50 divide the gas passage 52 into two smaller passages. Petition 870220101418, dated 03 / 11 / 2022, pp. 84 / 99 15 / 19
[059] The grid bar 10 further comprises a second interlocking means 60 on the longitudinal side surfaces 28 adjacent to the end sections 16, 18. The second interlocking means 60 comprises a first protrusion 62 projecting from the side surfaces 28 of the second end section 18 of the main beam 12, positioned at a predefined distance from the end surface 30. Its corresponding second interlocking element 60 is formed by a second protrusion 64 on the opposite side surface 28 of the main beam 12 at the second end section 18. The second protrusion 64 is positioned at an increased distance from the end surface 30 as the first protrusion 62. A corresponding arrangement of the first and second protrusions 62, 64 is provided at the first end section 16.
[060] Since grid bar 10 is arranged in a grid bar arrangement, protrusions 62, 64 are arranged in close proximity to protrusions 64, 62 of a neighboring grid bar. Protrusions 62, 64 thus form a contiguity with each other in the longitudinal direction L, so as to avoid misalignment of the grid bars.
[061] Although Figures 1 to 3 show protrusions 62, 64 with a rectangular shape, it is also possible to provide other shapes. Triangular protrusions, as shown in Figure 5, can, for example, be arranged so that the protrusions not only form a contiguity in the longitudinal direction L, but also in the vertical height direction H. The triangular protrusions shown in dashed highlight are located on the other side of the grid bar and are represented here to show their cooperation with the triangular protrusions of a neighboring grid bar.
[062] The grid bar 10 further comprises a third interlocking means 70 on the longitudinal sides of the legs 14 of the grid bar 10. On one of the longitudinal sides, the third interlocking means is formed by a horizontal upper edge 72 on the horizontal branch 36 of the leg 14. On the other side Petition 870220101418, dated 03 / 11 / 2022, pp. 85 / 99 16 / 19 longitudinally, the third interlocking means is formed by a horizontal lower flange 74 on the horizontal branch 36 of leg 14. The lower flange 74 is positioned lower than the upper flange 72 and positioned longitudinally, so that, since the grid bar 10 is arranged in a grid bar arrangement, the upper and lower flanges 72, 74 form a contiguity with each other in the vertical height direction H. To further enhance the robustness of the overlapping connections between adjacent grid bars, the position of the upper and lower flanges 72, 74 is reversed on the other leg of the grid bar.
[063] As can also be seen from Figure 1, the intermediate section of the main beam 12 may have a cross-section that narrows downwards towards the lower surface 24. This allows reducing the weight of the grate bar 10 and guiding the gas flow to the region under or away from the grate bar.
[064] In addition, a stiffening rib 80 is disposed on the lower surface 24 of the main beam 12. The stiffening rib 80 extends between the two legs 14 and below the inner sides of the legs 14. This stiffening rib 80 enhances the stiffness of the grid bar 10 with a limited amount of material. In the center of the intermediate section 20, the stiffening rib 80 comprises a recess 82, which also reduces the material weight. The recess 82 also helps to reduce stress peaks in critical areas of the grid bar 10. The recess 82 can be an enlarged rounded section as shown in Figure 2. Alternatively, the recess 82 can be a smaller tip area as, for example, shown in Figure 5.
[065] An alternative grid bar according to a third embodiment is shown in Figure 6. According to this embodiment, the third interlocking means 70 is, on one side of the grid bar, formed by a first U-shaped flange 90 extending through the horizontal branch 36 of the leg 14, through the vertical branch 34 of the leg 14 and through the end portion 16 of the main beam 12 to the transverse end surface 30. A corresponding second U-shaped flange 92 is disposed on the other side of the grid bar. This Petition 870220101418, dated 03 / 11 / 2022, pp. 86 / 99 17 / 19 second U-shaped edge 92 is, however, slightly offset. In fact, on the horizontal branch 36 of leg 14, it is positioned slightly lower, on the end portion 16 of the main beam 12 it is positioned slightly higher, and on the vertical branch 34 of leg 14, it is positioned slightly further inward. Both U-shaped flanges 90, 92 of two adjacent grid bars act as contiguity between each other to prevent movement of grid bar 10 in the longitudinal direction L and the vertical height direction H.
[066] Grid bar 10 in Figure 6 also shows a main beam 12 with an essentially concave upper surface 22. Such a concave upper surface may be advantageous to prevent wear of the grid bar in pelletizing machines.
[067] In normal operation, the second and third interlocking means 60 are not in contact with each other. They only come into contact when one of the grate bars becomes slightly misaligned. The second and third interlocking means 60, 70 then prevent the grate bar 10 from forming further misalignments. The third interlocking means 70, particularly the U-shaped rim 90, 92 according to the third embodiment of Figure 6, forms a kind of labyrinth seal preventing any bulk material from reaching the grate bar supports on which the grate bars 10 rest.
[068] The upper surface of the main beam may be concave or convex in shape to increase its resistance to wear.
[069] In pelletizing machines, it has been found that most of the wear occurs at the end sections 16, 18 of the main beam 12. The grid bars for use in pelletizing machines are therefore advantageously provided with a convex upper surface, as shown in Figures 2 or 5. By increasing the amount of material at the end sections of the main beam, the latter are better protected against wear.
[070] In sinter machines, on the other hand, the greatest wear occurs at the intermediate section 20 of the main beam 12. The grid bars for use in sinter machines Petition 870220101418, dated 03 / 11 / 2022, pp. 87 / 99 18 / 19 are therefore advantageously provided with a concave upper surface, as shown in Figure 6. By increasing the amount of material in the center of the main beam, the intermediate section is better protected against wear. LIST OF NUMERICAL REFERENCES Longitudinal direction Transverse direction Height direction Median line grid bar main beam legs first end section second end section intermediate section top surface bottom surface longitudinal side surfaces transverse end surfaces vertical leg branch horizontal leg branch first interlocking means first row of grid bars second row of grid bars gap triangle-shaped apex spacer gas passage second interlocking means first protrusion Petition 870220101418, dated 03 / 11 / 2022, pp. 88 / 99 19 / 19 second protrusion third interlocking means upper edge lower edge stiffening rib recess first U-shaped edge second U-shaped edge Petition 870220101418, dated 03 / 11 / 2022, pp. 89 / 99
Claims
1 / 4 CLAIMS 1. Grid bar (10) for mounting in arrangements of adjacent grid bars on a pallet car of a sintering or pelletizing machine, wherein said grid bar (10) is characterized by comprising an elongated main beam (12) extending in a longitudinal direction from a horizontal plane, with an intermediate section (20) between two opposite side sections (16, 18), wherein said main beam (12) has a generally rectangular cross-section with an upper surface (22) for receiving bulk material thereon, an opposite lower surface (24) and peripheral surfaces (28, 30) facing the adjacent grid bars; wherein said main beam (12) comprises two legs (14) for vertically attaching said grid bar (10) to said pallet car;and wherein said end sections (16, 18) of said main beam (12) comprise first interlocking means (38), said first interlocking means (38) being shaped and arranged so that they cooperate with the first interlocking means of grid bars of a neighboring row of grid bars; thus limiting relative translations of two neighboring grid bars in at least one vertical and one horizontal orientation, said first interlocking means (38) having a triangular cross-section in a horizontal plane.
2. Grid bar, according to claim 1, characterized in that an apex (48) of said triangular cross-section is located on a medial line (M) between two lateral surfaces (28) of the main beam (12).
3. Grille bar, according to any one of claims 1 to 2, characterized in that said intermediate sections (20) of said main beam (12) comprise a spacer (50), the spacers (50) being positioned and dimensioned to define, in use, a gap (44) between neighboring main beams that form a gas passage (52) for an inlet gas flow. Petition 870220101418, dated 03 / 11 / 2022, pp. 90 / 99 2 / 4 4. Grid bar, according to claim 3, characterized in that a single spacer (50) is located in the center of the intermediate section (20) on either side of the main beam (12).
5. Grille bar, according to claim 3 or 4, characterized in that said spacer (50) has a shape that narrows in the direction of the inlet gas flow.
6. Grid bar, according to any one of claims 1 to 5, characterized by further comprising a second interlocking means (60), said second interlocking means (60) comprising first and second protrusions (62, 64) projecting from said lateral surfaces (28) of the first and second end sections (16, 18) of the main beam (12), said first and second protrusions (62, 64) being dimensioned and positioned in a staggered arrangement so that, in use, the first protrusions (62) of a grid bar (10) cooperate with second protrusions (64) of a neighboring grid bar 10 to form a contiguity in a longitudinal direction (L) of the grid bar (10).
7. Grill bar, according to claim 6, characterized in that said first and second protrusions (62, 64) have a rectangular or triangular cross-section.
8. Grid bar, according to any one of claims 1 to 7, characterized by further comprising a third interlocking means (70), said third interlocking means (70) being disposed on said leg 14, said leg (14) comprising a vertical branch (34) essentially perpendicular to the main beam (12), and a horizontal branch (36) essentially parallel to the main beam (12) and extending outwards in a longitudinal direction (L) from the grid bar (10).
9. Grid bar, according to claim 8, characterized in that said third interlocking means (70) comprises an upper edge (72) on one side of a leg (14) and a lower edge (74) on the other side of the leg (14); Petition 870220101418, dated 03 / 11 / 2022, p. 91 / 99 3 / 4 wherein the upper and lower edges (72, 74) are dimensioned and positioned in a staggered arrangement so that, in use, an upper edge (72) of a grid bar (10) cooperates with a lower edge (74) of a neighboring grid bar (10) to form a contiguity in a vertical height direction (H) of the grid bar (10), wherein said upper and lower edges (72, 74) are arranged in said horizontal branch (36) of said leg (14).
10. Grid bar, according to claim 8, characterized in that said third interlocking means (70) comprises - a first U-shaped edge (90) disposed on one side of the grid bar, said first U-shaped edge 90 extending through the horizontal branch (36) of the leg (14), through the vertical branch (34) of the leg (14) and through a final portion (16, 18) of the main beam (12), - a second U-shaped edge (92) disposed on the other side of the grid bar, said second U-shaped edge (92) having a shape corresponding to that of said first U-shaped edge (90), but offset, so that, in use, a first U-shaped edge (90) of a grid bar (10) cooperates with a second U-shaped edge (92) of a neighboring grid bar (10) to form a contiguity in a vertical height direction. (H) and longitudinal direction (L) of the grid bar (10).
11. Grid bar, according to any one of claims 1 to 10, characterized in that the upper surface (22) of the main beam (12) has a concave or convex shape.
12. Grid bar, according to any one of claims 1 to 11, characterized in that, in said intermediate section (20), said main beam (12) has a cross-section that narrows downwards towards the lower surface (24).
13. Grid bar, according to any of claims 1 to 12, characterized by further comprising a stiffening rib (80) which is disposed on the lower surface 24 of the main beam (12), wherein said stiffening rib (80) preferably extends downwards on the inner sides of said legs (14).
14. Grid bar, according to claim 13, characterized in that said stiffening rib (80) comprises a recess (82) in the center of the intermediate section (20).
15. Arrangement of grid bars characterized by comprising two or more rows of grid bars (10), as defined in any one of claims 1 to 14, wherein, within each row, the grid bars (10) are arranged adjacent to each other, and wherein the first interlocking means (38) of the grid bars (10) of one row (40) cooperates in an interlocking manner with the first interlocking means (38) of the grid bars of the neighboring row (42).
16. Pallet car of a sintering or pelletizing machine, said pallet car being characterized by comprising a grid with a plurality of arrangements of adjacent grid bars (10) that creates a flat surface for receiving bulk material thereon, which comprises grid bars (10) as defined in any one of claims 1 to 14.
17. Sintering or pelletizing machine characterized by comprising a pallet carriage equipped with a grid bar arrangement, as defined in claim 15. Petition 870220101418, dated 03 / 11 / 2022, p. 93 / 99