Segmented roller with hardened material tiles

Abstract

Industrial rollers, particularly for use in a materials-processing or mining-related industry, having a rotatable cylindrical hub with a high hardness working surface that comprises a plurality of removable and replaceable surface tiles having depressions therein. Examples of high hardness materials include metallic carbides (e.g., tungsten, chromium, molybdenum, vanadium), tool steels, high alloy steels including carbide making elements such as tungsten, chromium, molybdenum, vanadium in the composition, and composite materials. The rollers are for briquetting or otherwise compacting granular, powdered, or particulate material, such as iron ore.

Description

SEGMENTED ROLLER WITH HARDENED MATERIAL TILESCROSS-REFERENCE

[0001] This application claims priority to U.S. provisional application no. 63 / 690,235 filed September 3, 2024 and titled SEGMENTED ROLLER WITH METALLIC CARBIDE TILES, the entire disclosure of which is incorporated herein by reference for all purposes.BACKGROUND

[0002] Compaction-based press rollers are common components of many machines. A frequent problem with such rollers is wear on the roller surface over time, particularly if the roller is subjected to large frictional forces. When the surface of the roller begins to wear out or becomes uneven, the roller must then be replaced or the surface of the roller must be remanufactured.

[0003] Frictional wear is particularly problematic for industrial rollers that are used extensively in high throughput compaction or pressing of a stream of particulate materials, especially those used to make high density individual output products, such as briquettes. Two basic types of industrial rollers are commonly used: the first being a single roller operating adjacent to a stationary curved anvil plate and the second being a double counter-rotating set of rollers having parallel axes and a gap between the rollers.

[0004] In many industrial applications, rollers are subjected to extremely high pressures, particularly when used to compress or compact relatively hard materials, both of which can result in significant frictional wear as well as deformation of the surface features on the rollers. A common symptom of such wear is known as 'dishing', in which the surface of the roller develops an excessive concave profile over time, though other unwanted deformations will occur.

[0005] Industrial rollers also often have surface features such as grooves or depressions or cups that assist with the compaction or compression action of the roller. Depressions or grooves on the roller surface can also be used to retain milled material on the roller surface, as a means of reducing wear on the roller surface. However, like the roller surface itself, surface features also wear out over time due to friction and mechanical stress.

[0006] When an industrial roller, either the roller itself or the surface feature, reaches the end of the service life, the roller or part thereof is replaced or remanufactured. In manyapplications, industrial rollers can be quite large, so remanufacture of the entire roller or its surface feature is often preferred over complete replacement of the roller or its surface feature. Even remanufacture of a worn roller, even only its surface feature, is not a simple or inexpensive task; it usually involves removal of the entire drum from service, followed by extensive cutting, machining, and re-welding of the surface of the drum.

[0007] Better rollers and more efficient methods for remanufacturing those rollers and their surface features is needed.SUMMARY

[0008] The present disclosure is directed to industrial rollers, particularly for use in a materials-processing or mining-related industry. The disclosure describes rollers and individual surface tiles, hubs, and retention structures, which may be provided in the form of a kit, for creation of a roller or roller assembly for briquetting or otherwise compacting granular, powdered, or particulate material, such as iron ore.

[0009] According to one broad aspect, described herein is a rotatable hub having a hardened or hard material (e.g., having a hardness of 60-80 HRC) working surface that comprises a plurality of replaceable surface tiles having depressions therein. These tiles can be removed and replaced, e.g., to recondition the working surface of the roller. The surface tiles are fastened to a central hub at engagement structures that attach the surface tiles to the hub but which also permits the tiles to be removed from the hub.

[0010] Examples of suitable hardened or hard materials for the tiles include metallic carbides (e.g., tungsten, chromium, molybdenum, vanadium), tool steels including grades A681, ASTM A597 and their equivalents, high strength low alloy forged steel, high strength high alloy steels including carbide making elements having tungsten, chromium, molybdenum, or vanadium in the composition, chromium white iron (CWI), and composite materials including ceramics and materials having nanofibers or nanoparticles. The entire tile may be formed from the hardened or hard material or the material can be applied as a hard coating on a base substrate.

[0011] Each surface tile has an outer surface which forms a portion of the working surface of the assembled roller. Collectively, the surface tiles may form all or substantially all of the working surface of the assembled roller. In some embodiments, there may be several surfacetiles along the axial length of the roller, arranged in circumferential rows. The surface tiles in adjacent rows can be staggered, e.g., to extend the life of the roller assembly. The surface tiles may meet at an oblique angle relative to the direction of rotation. In other embodiments, each surface tile extends along the entire axial length of the roller assembly.

[0012] The surface tiles can be directly fastened to the hub using bolts or other fastener, or the surface tiles can be removably attached via engagement structures such as channels or projections (e.g., a key way) which form an interlocking relationship with the surface tiles. Tiles can be replaced individually to correct localized defects in the outer surface of the roll, or replaced en masse to recondition all or substantially all of the working surface of the roll.

[0013] It is possible to retrofit traditional large segmented rollers with a plurality of the surface tiles. In some embodiments, a segment base is converted to receive a plurality of surface tiles, with the surface tiles being the working surface of the segment and the roller. In an alternate embodiment, multiple surface tiles may be combined to form a segment.

[0014] These and other aspects of the technology described herein will be apparent after consideration of the Detailed Description and Figures herein. It is to be understood, however, that the scope of the claimed subject matter shall be determined by the claims as issued and not by whether given subject matter addresses any or all issues noted in the Background or includes any features or aspects recited in the Summary.BRIEF DESCRIPTION OF THE FIGURES

[0015] FIG. l is a perspective view of a typical roller assembly in which the compacting or pressing surfaces are arranged in large segments.

[0016] FIG. 2 is a perspective view of another typical roller assembly in which the compacting surfaces are arranged in large segments.

[0017] FIG. 3 is a perspective view of a roller in which the compacting or pressing surfaces are arranged in individual surface tiles.

[0018] FIG. 4 is a perspective view of the roller of FIG. 3, partially exploded.

[0019] FIG. 5 is a cross-sectional view of a clamping detail of the roller of FIGS. 3 and 4.

[0020] FIG. 6 is an end view of the roller of FIGS. 3 and 4.

[0021] FIG. 7 is a cross-sectional view taken along line A-A of FIG. 6.

[0022] FIG. 8 is a side view of the roller of FIGS. 3 and 4.

[0023] FIG. 9 is a perspective view of a surface tile.

[0024] FIG. 10 is a top plan view of the surface tile of FIG. 9.

[0025] FIG. 11 is a cross-sectional view taken along line B-B of FIG. 10.DETAILED DESCRIPTION

[0026] As indicated above, described herein are roller assemblies having hard or hardened material surface tiles with concavities or depressions therein for the formation of briquettes from powdered, particulate, or granular material such as iron ore.

[0027] Also described herein are individual surface tiles, hubs, and retention structures, which may be provided in the form of a kit, for creation of a roller assembly. The surface tiles are removable and replaceable on the hub, allowing for replacement of individual surface tiles as needed or desired.

[0028] The surface tiles may be directly fastened to the hub using bolts or the like. Alternately, the surface tiles are fastened with engagement structures that are channels or projections which form an interlocking relationship so that the surface tiles are slid into place, e.g., from an end face of the hub, with retention structures used to secure the tiles against movement along the engagement structures. The retention structures may be annular plates or section thereof that attach to the end face of the hub and engage the surface tiles to prevent their exit from the channel or projection, or may be members (such as edge reinforcements) which slidably engage the end face of the hub and block the exit of the surface tiles from the channel or projection. Still further, the outermost surface tiles in a row may be directly fastened to the hub, thereby holding the surface tiles therebetween in place.

[0029] The surface tiles may be removed from the hub and replaced without removing the hub from the shaft. Alternatively, the hub may be removed from the shaft for replacement of all or some of the tiles, thereby permitting quick replacement of the roller assembly while the worn roller is being reconditioned. Tiles can be replaced individually to correct localized defects in the outer surface of the roll, or replaced en masse to recondition all or substantially all of the working surface of the roll.

[0030] The surface tiles may be attached to the hub with gaps between adjacent tiles, which may provide reduced edge wear. Such gaps may be provided by configuring theengagement structure on the hub and / or the surface tile with dimensions that generate these gaps when the tiles are mounted on the hub. Alternatively, or in addition, the gaps may be provided by an alignment member, which aligns the surface tiles on the hub in a such a manner so as to provide the necessary gap. The gap may be, e.g., less than 1 mm, or about 0.25 mm.

[0031] This disclosure also provides a method for reconditioning a roller, the method including removing one or more surface tiles (having depressions in the surface thereof) from an outer surface of the hub of the roller and fastening new surface tiles to the hub of the roller. The method may include aligning other or new surface tiles on the hub of the roller, prior to fastening, so as to create a gap between the adjacent surface tiles. The method may additionally or alternately include removing a retention structure and sliding the worn surface tiles off the end of the hub. New surface tiles are then slid into place and the retention structure is used to secure a row of surface tiles.

[0032] This disclosure also provides, in one aspect, a roller assembly having a hard or hardened working surface, such as a metallic carbide working surface, having depressions for compacting or shaping a particulate material, the roller assembly comprising a hub configured for mounting to a shaft, said hub rotatable about a longitudinal axis and having a length (e.g., an axial length) parallel to the axis, and an exterior surface; one or more engagement structures disposed on the exterior surface of the hub, preferably along the length of the hub; and a plurality of replaceable surface tiles configured for releasably attaching to said one or more engagement structures, each of the plurality of surface tiles having an inner surface configured to engage at least one engagement structure and an outer surface opposed to the inner surface and having a plurality of depressions thereon, where the working surface comprises the depress! oned outer surface of at least one of the plurality of surface tiles.

[0033] The plurality of surface tiles can be releasably attached to the hub using a fastener, such as a bolt. Alternatively, or in addition, the inner surface of the plurality of surface tiles may slidably engage engagement structures on the hub. In some cases, the engagement structures include a plurality of projections (such as ridges, preferably substantially parallel to the axis and / or extending along the length of the hub) and the inner surface of the plurality of surface tiles has a corresponding structure such as a depression for forming an interlocking relationship with the engagement structures on the hub. In other cases, the engagement structures on the exterior surface of the hub include a plurality of channels (e.g., substantially parallel to theaxis and extending along the length of the hub) and the inner surface of the plurality of surface tiles has a corresponding projection, for forming an interlocking relationship therewith. In some instances, the interlocking relationship has a dovetail profile, a T-shape profile, ball and socket profile, head and stalk profile, or a U-shaped dovetail profile.

[0034] The projections or channels on each of the inner surfaces of the plurality of surface tiles may be between about one-quarter to one-half the width of the surface tile, such as about one-third the width of the surface tile. In other cases, the projections or channels on each of the inner surfaces of the plurality of surface tiles are greater than one-half the surface tile, such as about two-thirds or three-quarters the width of the surface tile. The projections or channels are typically centered on the tile.

[0035] The roller assembly can include a removable retention structure for inhibiting or preventing movement of the plurality of surface tiles relative to at least one of the engagement structures. In some cases, the retention structure is an annular plate on at least one of the opposing faces of the hub, the annular plate engaging at least one of the plurality of surface tiles to prevent movement thereof. In other cases, the retention structure is an edge reinforcement that engages at least one of the opposing faces of the hub, or a retainer plate fastened to at least one of the opposing faces of the hub. The retention structure or edge reinforcement may also abut or otherwise engage at least one of the plurality of surface tiles to prevent axial and / or circumferential movement thereof. A slidable engagement of the retention structure may be mediated by a mortise and tenon relationship, such as a dovetail or a U-shaped dovetail. In still further cases the retention structure may be a bolt that fastens at least one surface tile to the hub at a position proximate to at least one opposing face of the hub.

[0036] In some embodiments, the outer surfaces of the plurality of surface tiles are arcuate in cross section and the inner surfaces of the plurality of surface tiles are parallel to the outer surfaces, also arcuate in cross section. In other embodiments, the outer surfaces of the plurality of surface tiles are arcuate in cross section and the inner surfaces of the plurality of surface tiles are substantially planar. The outer surfaces of the plurality of surface tiles may form greater than 80%, greater than 90%, greater than 95%, or substantially all of the working surface. The surface tiles may be substantially square, rectangular, triangular, parallelogram-shaped or rhomboid, or other suitable shape. Multiple surface tiles are installed on a hub, preferably in a repeating geometric pattern.

[0037] The plurality of surface tiles can be arranged on the outer surface of the hub in at least two adjacent rows extending the length of the hub, e.g., axially along the length of the hub. One or more surface tiles in the first row may be staggered with respect to one or more surface tiles in the second, adjacent, row. In other embodiments, at least two of the plurality of surface tiles are arranged on the outer surface of the hub in at least one row extending between the opposing faces of the hub. Two or more adjacent surface tiles in the at least one row can meet at an oblique angle relative to the direction of rotation, preferably less than 90 degrees, less than 60 degrees, or between 55 and 45 degrees.

[0038] In some embodiments, the plurality of surface tiles are arranged in three axial rows, four axial rows, six axial rows, or even more rows, depending on the dimensions of the surface tiles and the hub. Each row has at least one surface tile, two surface tiles, three surface tiles, etc.; the number of surface tiles in an axial row may be sufficient to extend the entire length of the hub and roller assembly.

[0039] The outer surfaces of the plurality of surface tiles include surface features, particularly, concave regions in the form of depressions. Individual depressions shapes may be circular, oval, square, rectangular, triangular, pentagonal, hexagonal, octagonal, or other polygon shape. Other depression shapes include stripes, e.g., intersecting stripes. The depressions may be rounded (e.g., semi-circular) or have straight or angular walls and base (e.g., cubic, tapered). Depending on the dimensions of the surface tiles and of the depressions, multiple depressions are present on each surface tile.

[0040] In the following description, reference is made to the accompanying drawing that forms a part hereof and in which is shown by way of illustration at least one specific implementation. The following description provides additional specific implementations. It is to be understood that other implementations are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the examples, including the figures, provided below. In some instances, a reference numeral may have an associated sub-label consisting of a lower-case letter to denote one of multiple similar components. When reference is made to a reference numeral without specification of a sub-label, the reference is intended to refer to all such multiple similar components.

[0041] FIG. 1 illustrates an example of a materials-processing industry roller assembly 100, which is a rotatable cylindrical member with a working surface for briquetting or otherwise forming, compressing, compacting powdered or granular material such as iron ore. The roller assembly 100 has a central hub 110 with a center aperture 115 for securely mounting to a shaft 120 in a non-rotatable manner. In use of the roller assembly 100, rotation of the shaft 120 drives the roller assembly 100. Attachment of the hub 110 to the shaft 120 may be provided by any suitable structure or technique known in the art, such as shrink fitting of the hub 110 onto the shaft 120 by the application of heat. In other designs, the hub 110 may be solid and the shaft 120 connects to or is integral with one or both opposing faces of the hub 110.

[0042] The hub 110 has an outer surface 125 to which at least one surface segment 130 is mounted. One of more of these surface segments 130 form some or all of the working surface of the roller assembly 100. In this design, one surface segment 130 occupies a radial distance of 120 degrees; thus, three surface segments 132, 134 and a third surface segment (not called out) encircle the hub 110. Multiple groups of surface segments 130 can be stacked on the hub 110 to cover the desired length of the shaft 120. FIG. 1 shows two sets of three surface segments 130 mounted on the hub 110, each set of three extending circumferentially around the hub 210. The two sets are shown axially spaced from each other on the hub 110; this is merely a convenience for understanding of the arrangement, and in use the two sets of surface segments 130 are adjacent to each other.

[0043] FIG. 2 illustrates another example of a roller assembly 200, also having a central hub 210 with a center aperture 215 for mounting to a shaft 220. In use of the roller assembly 200, rotation of the shaft 220 drives the roller assembly 200. As with the assembly 100 of FIG. 1, the hub 210 has an outer surface 225 to which at least one surface segment 230 is mounted; one tile 230 is shown removed from the hub 210. In this design, one surface segment 230 occupies a radial distance of 60 degrees; thus, six surface segments 232, 234, 236 and three more surface segments (not called out) encircle the hub 210. Multiple groups of surface segments 230 can be stacked on the shaft 220; FIG. 2 shows two sets of six surface segments 230 mounted on the shaft 220, each set of six extending circumferentially around the hub 210. The two sets are shown axially spaced from each other on the hub 210; this is merely a convenience for understanding of the arrangement, and in use the two sets of surface segments 230 are adjacent to each other.

[0044] For both the roller assemblies 100, 200, the surface segments 130, 230 are attached to the respective hub 110, 210 by a mechanical attachment, such as a bolt or screw, passing through the surface segments 130, 230, as seen in both FIGS. 1 and 2. In other designs, the surface segments 130, 230 may be welded or brazed to the hub 110, 210.

[0045] The configuration and dimensions of the surface segments 130, 230, the hub 110, 210, and the shaft 120, 220 can be sized as appropriate for a selected application of the roller assembly 100, 200. The surface segments 130, 230 are formed from a hard or hardened material, as is discussed further below. The hub 110, 210 and / or the shaft 120, 220 may be fabricated from a suitable metal, e.g., steel, e.g., a high strength low alloy forged steel.

[0046] FIGS. 3 and 4 show a roller 300, prior to mounting on a shaft. When mounted on a shaft, the roller 300 with the shaft form a roller assembly.

[0047] The roller 300 has a hub 310 (FIG. 4), in this particular design a cylindrical hub, with an outer surface to which a plurality of surface tiles 330 is mounted; in both FIGS. 3 and 4, one tile 330 is shown removed from the hub 310 to emphasize the tile 330. Unlike the roller assemblies 100, 200 described above, the roller 300 has many surface tiles 330 extending along the length of the hub 310, arranged in axial rows, forming the working surface 335 of the roller 300. The number of tiles 330 in each axial row can vary depending on the size and shape of the tiles 330, the application for the roller, and the length of the roller 300; for example, the number of tiles 330 may be at least two, at least three, at least four, at least five, such as six, seven, eight, nine, ten, 12, 15, 20, or more. Similarly, the roller 300 has many surface tiles 330 extending around the circumference of the hub 310, arranged in circumferential rows. The number of tiles 330 in each circumferential row can vary depending on the size and shape of the tiles 330, the application for the roller, and the diameter of the roller 300; for example, the number of tiles 330 may be at least three, at least four, at least six, such as 12, 20, 24, 25, 26, 30, or more.

[0048] In this design, one surface tile 330 occupies a circumferential distance of about 14 degrees, so that about 25 or 26 surface tiles 330 encircle the hub 310 in a circumferential row. In this particular design, six surface tiles 330 extend in an axial row parallel to the axis of the shaft on which the roller assembly 300 will be mounted. When 25 surface tiles 330 encircle the hub 310 forming a circumferential row, and there are six such circumferential rows, 150 surface tiles are used in the complete roller 300; when 26 surface tiles 330 encircle the hub 310 in a circumferential row, and there are six such circumferential rows, 156 surface tiles are used in thecomplete roller 300. The number of tiles 330 can vary between axial rows and / or circumferential rows. Other arrangements would also be possible depending on the size of the tiles 330, the diameter of the hub 310, and the length of the roller 300. For example, the tiles 330 in an axial row may be axially or longitudinally offset from the tiles in an adjacent axial row.

[0049] The plurality of surface tiles 330 make up greater than 80%, 90%, or 95% of the working surface 335 of the roller 300, although in most embodiments the surface tiles 300 cover all or substantially all of the working surface 335 of the roller 300.

[0050] The surface tiles 330 are releasably, and typically slidably, engaged with the hub 310. The outer surface 325 of the hub 310 has a plurality of engagement structures 340 extending axially and around the hub 310, best seen in the inset of FIG. 4, for engaging with the back or inner side of the surface tiles 330. One engagement structure 340 is used for each axial row of surface tiles 330. The engagement structure 340 may be integrally formed with the hub 310 or may be formed separate therefrom and then attached to the hub 310. The hub 310 and / or the engagement structure 340 may be fabricated from a suitable metal, e.g., steel, e.g., a high strength low alloy forged steel. Other suitable materials include chromium white iron (CWI), carbides (e.g., TiC, CrC, VC), nitrides (e.g., TiN, CrN), ceramics (e.g., AI2O3), and tool steels including grades ASTM A681, ASTM A597 and their equivalents. Additionally or alternately, a coating can be applied to the hub 310 and / or engagement structure 340. Examples of suitable coatings include carbides (e.g., TiC, CrC, VC), nitrides (e.g., TiN, CrN, CBN), diamond and diamond-like carbon (DLC), and ceramics (e.g., AI2O3); the coatings may be single layer or multilayer.

[0051] The engagement structure 340 on the outer surface of the hub 310 extends along the length of the hub 310 of the roller 300, substantially parallel to its rotational axis. This engagement structure 340 is received by a corresponding engagement structure 350 on the inner surface of the surface tile 330, thereby providing stability to the surface tile 330 both in the radial and circumferential direction, including when the roller 300 is in motion, particularly with regard to torsional forces. The engagement structures 340, 350 have a mortise and tenon relationship.

[0052] The engagement structure 340 on the hub 310 is provided as a male member that projects radially outward, in this case a rectangular projection; in other embodiments, the male member may be a trapezoid, dovetail, T-shape, head and stalk, or have another interlocking profile which limits movement of the surface tile 330 in the radial and circumferential directions.This engagement structure 340 interlocks with the corresponding engagement structure 350, in this case a female member formed as a rectangular channel, on the underside of surface tile 330; the corresponding engagement structure 350 should be shaped and sized to engage with the engagement structure 340. In other embodiments, the engagement structure 340 on the hub 310 can be a female member and the engagement structure 350 on the tile 330 can be a male member.

[0053] Although the engagement structures 340, 350 shown extend along the length of the roller 300, other lengths are also contemplated. For example, the engagement structures 340, 350 could extend for less than the full length of the roller 300. Additionally or alternately, the engagement structures 340, 350 can include multiple male and female members arranged along the length of the roller 300. In some embodiments, the engagement structures 340, 350 may not be parallel to the axis of the roller 300, such that the surface tiles 330 are arranged at an angle along the working surface of the roller 300.

[0054] In the particular design shown, the engagement structure 350 on the surface tile 330 is between one-third and one-half of the circumferential width of the surface tile 330. Similarly, the engagement structure 340 on the hub 340 is between one-third and one-half of the circumferential width of the surface tile 330. Various other widths and radial heights are also contemplated for the engagement structures 340, 350, such as one quarter to one half the width of the surface tile 330.

[0055] As indicated above, the engagement structures 340, 350 stabilize and inhibit movement of the surface tiles 330 in relation to the hub 310 both in the radial and circumferential direction. To stabilize and inhibit axial movement of an axial row of the surface tiles 330, present at each end of the roller 300 is at least one retention structure 360 removably fastened to an end face of the hub 310 and adjacent to the outermost surface tile 330. One annular retention structure may be present or multiple removable retention structures 360, which together form an annual structure, may be used; in FIG. 4, six removable retention structures 360 form an annular retention structure.

[0056] FIG. 5 shows the attachment of a retention structure 360 to the hub 310 against the outermost surface tile 330 with a fastener such as a bolt.

[0057] Once attached to a full row of surface tiles 330 in this manner, the retention structures 360 inhibit and preferably prevent sliding movement of the surface tiles 330 in theaxial direction and blocking disengagement of the engagement structure 350 from the corresponding engagement structure 340 on the hub 310.

[0058] Instead of the axial retention structures 360, it may be possible to use a series of bolts or other fasteners to secure one or more of the surface tiles 330 to the hub 310 in a manner akin to the bolts in the roller assemblies 100, 200 above. Where sliding engagement is used, the outermost surface tiles 330 in a row may be bolted to the hub 310 in order to secure a full row of surface tiles 330 against movement along the engagement structures 340, 350.

[0059] FIG. 6 shows an axial end view of the roller 300 and the retention structures 360, and FIG. 7 is a cross section taken along line A- A of FIG. 6, showing the hub 310, a surface tile 330 and the retention structure 360. A fully assembled roller 300 is shown in FIG. 8.

[0060] The roller 300, in one particular embodiment, has a maximum diameter of about 10 meters (9.96 m), an overall axial length of about 8 meters (8.36 m), with an axial length of the working surface 335 defined by the surface tiles 330 of about 7.5 meters (7.56 m). Other dimensions are possible depending on the industry application. For example, the diameter can be 5 meters to 12 meters, and the overall length can be about 5 meters to 20 meters.

[0061] An individual surface tile 330 is shown in FIGS. 9 and 10. The tile 330 has a front or working surface side 332 and a back side 334, with a plurality of depressions 370 on or in the front or working surface side 332. In the particular example shown, the tile 330 has 20 depressions (18 complete depressions and four half depressions) arranged in an orderly fashion in four offset rows; in other embodiments, the depressions may be arranged randomly. Each depression 370 on a tile 330 is an individual concave region unconnected to any other depression 370. In the embodiment shown, the depressions 370 are concave depressions having an oval shape, or, a rectangular shape having radiused corners. Other suitable shapes include circular, square, rectangular, triangular, pentagonal, hexagonal, octagonal, and other polygon shapes. The side walls of the depressions 370 (extending from the front surface side 332 toward the back side 334) may be radiused, angled / tapered or straight, and the bottom wall of the depressions 370 may be radiused or straight. FIG. 11 shows the oval, concave depression 370 in cross section. Depressions 370 having straight side walls and bottom wall, even though cubic, are also concave.

[0062] As indicated above, the particular design of the surface tile 330 shown in FIGS. 9 and 10 includes half depressions 370. When the surface tile 330 is abutted to an adjacentsurface tile 330, the half depressions from each tile 330 join to form a complete depression. It is understood that other surface tiles may not have partial depressions.

[0063] The surface tiles 330, in one particular embodiment, are about a 120 mm square, with about a 59 mm channel in the back side as an engagement member. The depressions 370 are about 30 mm by about 21 mm in size, and are spaced about 24 mm on center in one direction and about 31 mm on center in the other direction. It is understood that other surface tiles may have different dimensions and / or different depressions sizes, shapes, and orientations.

[0064] In one specific embodiment, the surface tiles 330 have a maximum working surface dimension of 123.56 mm to 120.54 mm with multiple depressions 370 having a surface area of 30.5 mm by 20.6 mm and a maximum depth of 5.5 mm present in that working surface. Of course, other dimensions are suitable. In general, example surface tiles 330 may have a maximum working surface dimension of about 100 mm to 200 mm with depressions 370 having a surface area of about 20 to 40 mm by 10 to 30 mm and a depth of 4 mm to 10 mm.

[0065] The depressions 370 occupy about 80-85% of the working surface area of the tiles 330. In other embodiments, the depressions 370 occupy about 75-95% of the working surface area of the tiles 330.

[0066] These depression 370, and variations thereof, are also found on the surface segments 130, 230 of the roller assemblies 100, 200.

[0067] The surface tiles 330 are formed from a hard or hardened material, such as those having a hardness of 60-80 HRC on the Rockwell scale.

[0068] Examples of suitable hard or hardened materials for the tiles include metallic carbides (e.g., tungsten, chromium, molybdenum, vanadium), tool steels including grades A681, ASTM A597 and their equivalents, high alloy steels including carbide making elements such as tungsten, chromium, molybdenum, vanadium in the composition, and composite materials including ceramics and materials having nanofibers or nanoparticles. The hard or hardened material is present on at least the front (working) side 332 of the tiles 330, typically also present on the surface of the depressions 370. In some embodiments, the entire surface tile 330 is formed from the hard or hardened material. This hard or hardened material, when present on the surface of the tile 330, may be provided as a coating; suitable coatings include carbides (e.g., WC, CrC, MoC or M02C, VC), nitrides (e.g., TiN, CrN, CBN), diamond and diamond-like carbon (DLC); the coatings may be single layer or multilayer. If the working surface and / or entire tile 330 is notpurely the hard or hardened material, then the amount of material, homogenously present either on the working surface or throughout the entire surface tile 330, is at least 80% in some embodiments, to at least 94% or even 95%. Other materials that may be present in the body of the tile 330 include steel, e.g., a high strength low alloy forged steel, chromium white iron (CWI), nitrides (e.g., TiN, CrN), ceramics (e.g., AI2O3), and tool steels including grades ASTM A681, ASTM A597 and their equivalents.

[0069] Similarly, the surface segments 130, 230 can be formed from a hard or hardened material. In some embodiments, a plurality of the surface tiles 330 may be present on and form the working surface of the surface segments 130, 230.

[0070] Having the surface tiles 330, as well as the surface segments 130, 230, made from a highly durable hard or hardened material results in the depressions 370 as well as the entire surface tile 330 retaining its quality and the desired configuration for a longer period of time than with other materials, hence providing savings in maintenance costs and operating delays due to maintenance.

[0071] In operation, a roller assembly 100, 200 or a roller 300 may be used for compacting, compressing, or briquetting powdered or granular material such as iron ore. For example, the roller assembly 100, 200 or the roller 300 may be positioned opposite to an opposing counter-rotating roller (not shown) to compact fed materials. In some embodiments, the counter-rotating roller also has hard or hardened depressioned surface tiles. Material fed into the roller enters the nip between rollers, where the surface segments 130, 230, and the surface tiles 330 compact material as it passes through the nip between the rollers.

[0072] When the roller assembly 100, 200 or the roller 300 reaches the end of its life (e.g., distorted, worn or broken surface segments, surface tiles and / or depressions), it can be reconditioned by replacing one or more worn surface segments 130, 230, and / or surface tiles 330 on the hub with new surface segments 130, 230 or new surface tiles 330. The replacement of one or more surface segments 130, 230 or surface tiles 330 in turn provides a new working surface for the roller assembly 100, 200 or the roller 300. Replacement of the surface segments 130, 230 or surface tiles 330, rather than the entire roller assembly 100, 200 or roller 300, also allows for reconditioning without the need to remove the roller from the shaft.

[0073] If the surface segments 130, 230 are bolted or others held by mechanical fasteners in place on the hub 110, 210, the surface segments 130, 230 may be removed by extracting the bolts or other fasteners.

[0074] If the surface tiles 330 are held on by one or more end retention structures 360, the roller 300 can be reconditioned by: a) removing the appropriate retention structure 360 from one or both ends of the hub 310 of the roller 300; b) sliding one or more of the surface tiles 330 along the engagement structures 340 on the hub 310 past the end face thereof; c) aligning replacement surface tiles 330 having an engagement structure 350 with the engagement structure 340 of the hub 310 to engage the engagement structure 350 with the engagement structure 340; d) sliding the surface tiles 330 onto and along the engagement structure 340 of the hub 310; and e) replacing the retention structure 360 to secure the surface tiles 330 against movement along the engagement structure 340.

[0075] The above specification and examples provide a complete description of the structure and use of exemplary implementations of the invention. The above description provides specific implementations. It is to be understood that other implementations are contemplated and may be made without departing from the scope or spirit of the present disclosure. The above detailed description, therefore, is not to be taken in a limiting sense. While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the examples provided.

[0076] Although the technology has been described in language that is specific to certain structures and materials, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Rather, the specific aspects are described as forms of implementing the claimed invention. Because many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

[0077] Various features and details have been provided in the multiple designs described above. It is to be understood that any features or details of one design may be utilized for any other design, unless contrary to the construction or configuration. Any variations may be made.

[0078] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties are to be understood as being modified by the term “about,” whether or notthe term “about” is immediately present. Accordingly, unless indicated to the contrary, the numerical parameters set forth are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0079] As used herein, the singular forms “a”, “an”, and “the” encompass implementations having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0080] Spatially related terms, including but not limited to, “bottom,” “lower”, “top”, “upper”, “beneath”, “below”, “above”, “on top”, “on,” etc., if used herein, are utilized for ease of description to describe spatial relationships of an element(s) to another. Such spatially related terms encompass different orientations of the device in addition to the particular orientations depicted in the figures and described herein. For example, if a structure depicted in the figures is turned over or flipped over, portions previously described as below or beneath other elements would then be above or over those other elements.

[0081] Similarly, directional terms such as "front" and "rear", "top" and "bottom", "first" and "second", "right" and "left" if used herein, are purely for convenience of description. Such terms are used for illustration purposes and are not intended to limit the present disclosure. As well, and dimensions herein are not intended to limit the scope of the invention unless specifically stated. Furthermore, geometric terms such as "straight", "flat", "point" and the like are not intended to limit the invention to the level of geometric precision, but should instead be understood in the context of the invention which includes such departures from geometric position as the manufacturing tolerances that are normal and / or acceptable in the field of this invention, as well as the functional requirements of products in the field of the invention wherein a high level of precision may not be required.

[0082] From the foregoing description and examples, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A roller for compacting a particulate, powdered or granular material into a briquette, the roller comprising: a cylindrical hub rotatable about a longitudinal axis, the hub comprising a plurality of tiles extending in an axial row and removably engaged with the hub, each tile having a working surface having a hardness of 60-80 HRC and at least one depression therein.

2. The roller of claim 1, wherein the working surface of each tile comprises a metallic carbide, tool steel, high alloy steel, ceramic, or a composite material.

3. The roller of claim 2, wherein the metallic carbide material is tungsten carbide, chromium carbide, molybdenum carbide, or vanadium carbide.

4. The roller of claim 1 comprising at least six tiles in the axial row.

5. The roller of claim 1 comprising at least three axial rows of tiles, each of the at least three axial rows having a plurality of tiles.

6. The roller of claim 1 comprising at least six axial rows of tiles, each of the at least six axial rows having the plurality of tiles.

7. The roller of claim 1 comprising at least 25 axial rows of tiles.

8. The roller of any of claims 2 to 7 comprising at least two circumferential rows of a plurality of tiles.

9. The roller of any of claims 2 to 7 comprising six circumferential rows of a plurality of tiles.

10. The roller of any of claims 2 to 7, wherein each of the plurality of tiles in the axial row is removably engaged with the hub by a mortise and tenon relationship.

11. The roller of any of the previous claims, wherein the at least one depression in the tiles is a concave depression.

12. The roller of claim 11, with each tile comprising a plurality of concave depressions arranged in an ordered fashion.

13. The roller of any of the previous claims, wherein the at least one depression occupies at least 75% of the working surface.

14. The roller of claim 13, wherein the at least one depression occupies at least 80% of the working surface.

15. The roller of any of the previous claims, wherein the working surface comprises pure metallic carbide material.

16. The roller of claim 15, wherein the entire tile comprises the metallic carbide material.

17. The roller of claim 15, wherein the entire tile comprises pure metallic carbide material.

18. The roller of claim 1, wherein a roller segment has been retrofitted to receive the plurality of tiles.

19. The roller of any of the previous claims, wherein the hub comprises one or more of steel, a high strength low alloy forged steel, tool steel, chromium white iron (CWI), a carbide (e.g., TiC, CrC, VC), a nitride (e.g., TiN, CrN), and a ceramic (e.g., AI2O3).

20. The roller of any of the previous claims, wherein the hub has a coating thereon, the coating comprising one or more of a carbide (e.g., TiC, CrC, VC, CBN), a nitride (e.g., TiN, CrN), diamond, diamond-like carbon (DLC), and ceramic (e.g., AI2O3).

21. A tile for the roller of claim 1, comprising a front side and an opposite back side, the front side forming the working surface having a hardness of 60-80 HRC and at least one depression therein occupying at least 75% of the working surface, and the back side having an engagement member therein, the engagement member being one of a mortise and tenon.

22. The tile of claim 21 comprising a metallic carbide material.

23. The tile of claim 21 or claim 22, the engagement member comprising one or more of steel, a high strength low alloy forged steel, tool steel, chromium white iron (CWI), a carbide (e.g., TiC, CrC, VC), a nitride (e.g., TiN, CrN), and a ceramic (e.g., AI2O3).

24. The tile of any of claims 21 to 23 having a coating on the engagement member, the coating comprising one or more of a carbide (e.g., TiC, CrC, VC, CBN), a nitride (e.g., TiN, CrN), diamond, diamond-like carbon (DLC), and ceramic (e.g., AI2O3).

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