Field of the Invention

This Invention relates to edge protection of high pressure rollers for use in the grinding of materials and in particular high pressure rollers utilised in semi- autogenous grinding mills.

Background

The following discussion of the background art is intended to facilitate an understanding of the present Invention only. The discussion Is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

It is a characteristic of semi-autogenous grinding mills that a portion of the grinding surface of the roller is formed of rock material which has been previously ground and which Is retained on the surface of the roller. The purpose of such a layer is to minimise wear upon the roller surface. To assist in the retention of this rock material the surface of the roller is provided with wear resistant elements at spaced locations. These elements typically are in the form of inserts which are embedded in the roller. During operation the gaps between and/or provided by the inserts fill with the material which has been comminuted by the roller press. The material builds up to form a continuous outer layer around the roller. This layer provides protection to the outer face of the roller and typically remains in place during the grinding action.

The provision of inserts in the roller surface provides a means by which the outer surface of the roller may be protected, However, it does not necessarily provide adequate protection to the edge and side faces of the roller which are also exposed to the harsh environment. Often the condition of the rest of the roller's working surface is still sound and it is only the failure of the edges that limits the life of the roller.

Currently there are several solutions to provide improved roller edge protection. In Australian patent 2004203273 to Poiysius, an edge protection assembly comprising a plurality of hard bodies secured at the roller's edge is disclosed. With this system a circumferential recess is formed at the roller's edge and the plurality of hard bodies are secured therein, one behind the other. Whilst this system initially provides sound edge protection, eventually the hard bodies wear and/or break away, leaving the edge, or portions of the edge exposed to the environment. The failure of one hard body, if not immediately replaced, results in further failures of adjacent edge protection hard bodies, exposing the roller's edges to wear. If the roller's edges are worn or damaged, it is not possible to replace the hard bodies which protect the edge as the edge is no longer able to support the hard bodies. In these cases, extensive repair to the roller Is required, or alternatively the entire roller will require replacement.

Another solution to provide improved roller edge protection is disclosed in Australian patent 2004291333 to KHD Humboldt Wedag GmbH. This system also proposes to provide protection to the roller edge by having a plurality of hard bodies secured in a peripheral annular shoulder of the roller, the hard bodies being arranged such that they extend both axially and radially from the roller surface. Again, this system initially provides sound edge protection but once the hard bodies wear or break away, the roller edge Is exposed to wear. Once the edge wears it is no longer possible to secure replacement hard bodies to that portion of the roller edge. Again, extensive repair to the roller is required, or alternatively, the entire roller will require replacement.

Disclosure of the Invention

Accordingly the invention resides in an edge protection assembly for a pressure roller used in the semi-autogenous comminution of materials, the roller having an outer face on a roller body, the outer face extending between two lateral faces, each junction of the respective lateral face with the outer face providing an edge portion, the edge protection assembly comprising: a plurality of side bodies adapted to be releasably secured to the lateral face of the roller, whereby when fitted each side body terminates at a position below the roller's outer face; a plurality of hard bodies adapted to be secured relative to the plurality of side bodies when the side bodies are secured to the roller, the hard bodies being arranged to support the edge portion of the roller.

The present invention facilitates the protection of the edge portion by, in effect, extending the edge portion of the roller's outer face, As a result, the edge portion is supported/reinforced such that its wear characteristics will be similar to that of other sections of the outer face. More importantly, the edge protection assembly may be readily replaced, regardless of the extent of wear of the outer edge of the roller. As the hard bodies are mounted to replaceable side bodies, the life of the roller may be extended. In the event that one or more of the hard bodies wears or breaks away from the roller, and the side body becomes damaged, the side body may be replaced and new hard bodies may be position to support the edge portion. This is not possible with the edge protection systems of the prior art.

Preferably the hard bodies provide an extension to the outer edge portion of the roller. Preferably the hard bodies are arranged in an end to end relationship. ln one aspect of the invention the gap between adjacent hard bodies is not sufficient to allow the ingress of material.

In another aspect of the invention, the hard bodies may be adapted to receive material therebetween, or in recesses formed in an edge of each hard body which abuts another hard body. As the material builds up between the hard bodies, the radial forces acting thereupon increase and assist in locking the hard bodies in place.,

Preferably when the side bodies are secured to the lateral face, the roller and side bodies define a plurality of groove portions spaced around the edge portion. Preferably the roller and side bodies define a circumferential groove extending adjacent the edge portion.

The groove may be adapted to receive the plurality of hard bodies therein.

In one aspect of the invention, one or more hard bodies may have a projection which extends from a surface thereof and is adapted to be received in a hole in one of the side bodies when the hard body is in position.

In another aspect of the invention one or more hard bodies may have a hole extending through the hard body . The hole may receive a dowel which is first received in the hard body before passing into a hole in one of the side bodies. Preferably when in position, an end face of the dowel is located beiow an outer face of the hard body to define a recess. This will allow the communited material to build up at the edge, providing enhanced wear protection in this region.

In a further aspect of the invention one or more of the hard bodies may have a recess in a surface thereof which is adapted to complement a recess in one of the side bodies, whereby when in place the recesses define a cavity. The cavity may be adapted to receive and retain a pin therein. Preferably an end face of the pin does not engage the bottom of the recess in the hard body. Once the hard body and pin are in place, the pin minimises/prevents movement of the hard body relative to the side body.

In yet a further aspect of the invention, one or more of the hard bodies may have a protrusion in a surface thereof, the protrusion being adapted to be received in a recess in one of the side bodies, whereby when the hard body is in position, the protrusion co-operates with the side body to minimises/prevent the movement of the hard body relative to the side body.

Each hard body may engage the respective side body using a dovetail arrangement. When in position, the dovetail arrangement prevents axial movement of the hard body away from the side body. This assists In locking the hard body relative to the roller, making it more difficult to remove the hard body from the roller when compared to the edge protection systems of the prior art.

Preferably the portion of the lateral face of the roller which extends beyond the side body is inclined inwardly from the outer face of the roller towards the roller axis such that the edge portion of the roller extends laterally into the groove.

Preferably a side face of each hard body Is adapted to engage the lateral face, the side face being inclined in a complimentary manner to the inclined portion of the roller's lateral face portion. When the hard body is in position the inclined side face of the hard body and inclined portion of the lateral face co-operate to allow for the even distribution of load. Furthermore, once the hard body is secured in position the inclined surface of the lateral face assists in retaining the hard body in position.

In one aspect of the invention, an outer surface of the hard body is flush with the roller's outer face. In another aspect of the invention the outer surface is curved. Preferably the curved outer surface has a portion which extends above the surface of the roller when in place. The curved surface encourages retention of material in the center of the roller. It also improves the load bearing capability and reduces the likelihood of the edge of the hard bodies from breaking off as the profile redistributes the load away from the edge.

The hard body provides an extension to the edge portion of the roller. It will also allow projections and/or recesses to be formed in the roller body closer to the lateral face of the roller. This will assist in the early formation of a protective layer of material, and will allow the layer to extend across the edge portion of the roller.

The hard body may comprise a wear resistance outer surface.

Each side body may be secured to the lateral face by bolting the side body through the lateral face into the roller body. Accordingly the invention resides in a pressure roller assembly , the assembly comprising a roller for use in semi-autogenous communition of materials, the roller having a plurality of replaceable side plates secured to each lateral face thereof, the side plates providing means to secure a plurality of hard bodies whereby the hard bodies define an outer edge of the pressure roller assembly. Preferably the hard bodies provide an extension to an outer surface of the roller.

Accordingly the invention resides in a pressure roller assembly for use in semi- autogenous communition of materials, the roller having a cylindrical outer face defined between two lateral faces, each lateral face co-operating with a plurality of replaceable side plates secured thereto to define an annular groove, the groove being adapted to receive a plurality of hard bodies secured to the side bodies whereby the hard bodies define an outer edge of the assembly.

Preferably the hard bodies provide an extension to an outer surface of the roller. Accordingly the Invention resides In a edge protection assembly for a pressure roller used in the semi-autogenous comminution of materials, the roller having an outer face on a roller body, the outer face extending between two lateral faces, each junction of the respective lateral face with the outer face providing an edge portion, the edge protection assembly comprising: at least one side body adapted to be releasably secured to the lateral face of the roller, whereby when fitted the at least one side body terminates at a position below the roller's outer face; a plurality of hard bodies adapted to be secured relative to the plurality of side bodies when the side bodies are secured to the roller, the hard bodies being arranged to support the edge portion of the roller.

Accordingly the invention further resides in a edge protection assembly for a pressure roller used in the semi-autogenous comminution of materials, the roller having an outer face on a roller body, the outer face extending between two lateral faces, each junction of the respective lateral face with the outer face providing an edge portion, the edge portion providing an annular recess, the annular recess providing a side face extending downwardly from the outer face of the roller, the side face being inclined inwardly from the outer face towards the axis of the roller, the edge protection assembly comprising: a plurality of hard bodies adapted to be received and secured in the annular recess whereby the hard bodies are arranged to support the edge portion of the roller, each hard body having an inclined side face complementary to and adapted to engage the inclined side face of the recess.

Preferably the plurality of hard bodies provide the outer edge portion of the roller. Preferably the hard bodies are arranged in an end to end relationship. Preferably the gap between adjacent hard bodies is not sufficient to allow the Ingress of material.

Preferably when in place, an outer face of the hard body is flush with the outer face of the roller.

Each hard body may be secured in the recess by a dowel passing therethrough. The dowel may be first received in a hole extending through the hard body before passing Into a hole in the recess. Preferably when in position, an end face of the dowel is located below an outer face of the hard body to define a recess. This will allow the communited material to build up at the edge to provide enhanced wear protection in this region.

Preferably a bottom face of the recess Is Inclined downwardly from the lateral face of the roller towards the roller axis. Each hard body may have an inclined bottom face complementary to and adapted to engage the inclined bottom face of the recess.

The inclined face of the recess and that of each hard body assist in retaining each hard body in place. Once the dowel is in position the inclined surfaces become load bearing surfaces and assist in the distribution of loads experienced by the hard bodies. In another aspect of the invention the annular recess is formed in the lateral face of the roller such that the outer face of the roller extends across the recess. The recess may be formed in close proximity to the outer face such that only a thin section of the outer face extends across the recess. Preferably the thin section may be flexed outwardly to allow each hard body to be positioned in the recess. The thin section may have a hole therein to allow the dowel to pass therethrough before it passes Into the hard body. The thin section may be formed above the outer face of the roller such that when the hard bodies are in place, the outer surface of each hard body align with the outer face of the roller.

Accordingly the invention resides in an ore grinding mill incorporating a pair of rollers each as herein before described, the rollers being supported in parallel spaced apart relationship and driven in contra-rotation so as in use to grind ore fed between the rollers.

Brief Description of the Drawings

The invention will be better understood by reference to the following description of several specific embodiments thereof as shown in the accompanying drawings in which:

Figure 1 is a side view of a roller having an edge protection assembly according to a first embodiment of the Invention secured thereto;

Figure 2(a)(b) are perspective views of a hard body for use in the edge protection assembly shown in figure 1;

Figure 3 is a schematic cross sectional side view along line A-A of Figure 1;

Figure 4 is a schematic cross sectional side view along line B-B of Figure 1 ;

Figure 5 is a schematic cross sectional side view along line C-C of Figure 1 ;

Figure 6 is a schematic cross sectional side view along line D-D of Figure 1 ; Figure 7 is a schematic partial sectional side elevation of section G of Figure 6;

Figure 8 is a schematic partial sectional side elevation of section E of Figure 3; Figure 9 is a schematic partial sectional side elevation of section F of Figure 5;

Figure 10 to 13 are views of an alternative hard body to that shown in figure 2, and which are configured to be used in a second embodiment of the present invention; Figure 14 is a schematic of a retaining pin according to the second embodiment;

Figure 15 is a close up section of the pin shown in figure 14;

Figure 16 and 17 are views of an alternative hard body to that shown in figure 2, and which are configured to be used in a third embodiment of the present invention;

Figure 18 is a side view of a roller having an edge protection assembly according to a fourth embodiment of the invention secured thereto;

Figure 19 is a schematic cross sectional side view along line A-A of Figure 18;

Figure 20 is a schematic cross sectional side view along line B-B of Figure 18; Figure 21 is a schematic partial sectional side view of section C of Figure 19; and

Figure 22(a)(b) are perspective views of a hard body for use in the edge protection assembly shown in figure 18.

In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention. Detailed Description of the Specific Embodiment

Each embodiment of the invention depicted in the figures is directed to enhance the longevity of a roller 10 utilising an edge protection assembly. The roller 10 of the present embodiments is intended for use in the high pressure, semi- autogenous grinding of material. In such a process it is highly desirable for ground ore material to be present on the outer face of the roller to effect at least part of the grinding action, in addition to providing a degree of protection to the outer face of the roller.

The roller 10 according to the embodiments is provided with a cylindrical outer face 11 extending between two lateral faces 12, whereby the junction of each lateral face with the outer face defines an edge portion 19. The outer face 11 has a number of pockets 15 formed therein so as to receive an insert 13 (not shown). The outer face 11 also provides a plurality of recesses 17. The configuration of the roller's outer face 11 is such that it assists in the formation of a layer of protective material once the grinding action commences.

A first embodiment of the invention Is depicted In figures 1 to 9. In this embodiment the edge protection assembly comprises a plurality of side bodies 21 releaeably secured to each lateral face 12. In the embodiment shown, the side bodies 21 are secured laterally to the roller by bolts 23 passing therethrough. Referring to figure 7, when the side bodies 21 are fitted to the lateral face 12, the side bodies 21 terminate a distance below the outer face 11 of the roller, leaving a lateral face portion 25 exposed. The lateral face portion 25 is angled outwardly as it approaches the outer face 11 , for reasons which will be described below.

The side bodies 21 and lateral face portion 25 co-operate to define a groove 27 which extends around the lateral face of the roller adjacent the outer face 11. The groove 27 is adapted to receive a plurality of hard bodies 29 in a back to back arrangement. Once installed the hard bodies 29 support the edge portion 19 of the roller 10. In the embodiment shown an outer face 31 of each hard body 21 is located flush with the outer face 11 of the roller to provide an extension of the outer face 11 of the roller.

Each hard body 29 Is received and retained to the respective side body 21 by a dovetail arrangement 33, as best shown In figure 7. A bottom face 35 of each hard body 29 has a projection 37 which is received in a recess 39 formed in an end face 41 of the side body 21. The projection 37 and recess 39 are configured such that the hard body 29 is wedged into position preventing the hard body from moving away from the side body 21 in an axial direction.

Each hard body 29 has a side face 43 which engages the lateral face portion 25 when the hard body 2Θ is in position. The side face 43 is Inclined so as to be complementary to the lateral face portion 25. This further assists in retaining the hard body 29 in position as the hard body 29 is further prevented from disengaging the side body 21 in an axial direction.

Each hard body 29 has a hole 44 therethrough adapted to receive a projection in the form of a dowel 45. The end face 41 of the side body 21 also provides a hole 47 which aligns with the hole 44 when the hard body 29 is in position. To secure the hard body 29 in position the dowel 45 passes into holes 44 and 47 as best shown in figure 9. Each hard body 29 and dowel 45 is further fixed in position by gluing, but may also be fixed by welding, screws, is keyed into position, be formed to have an interference fit or any other appropriate means.

When the dowel 45 is received in the hard body 29, an end face 49 of the dowel 41 is located below the outer face 31 of the hard body. This not only protects the dowel 45 but also provides a recess to assist in the build up of the protective layer across the outer face of the roller. In use, each hard body 29 supports and protects the edge portion 19 of the roller. Due to the harsh environment one or more hard bodies 29 may break away or wear down, exposing the side bodies 21. If the roller is not timely repaired, the side bodies 21 are then exposed to the harsh environment and will be damaged. If this were to occur, during maintenance an operator simply removes and replaces the side bodies 21, allowing new hard bodies 29 to be secured to the side bodies 21. This is not achievable with the prior art systems as prior art systems would require replacement of the roller edge. A second embodiment of the invention is shown in figures 10 to 15. For convenience features of the second embodiment that are similar or correspond to features of the first embodiment have been referenced with the same reference numerals.

The second embodiment differs from the first embodiment in that one or more of the hard bodies 229 are formed with a recess 231 in the surface which engages the side body 21. In this embodiment the side body 21 is also formed with a recess 233 which, once the hard body 229 Is in place, aligns with the recess 231 of the hard body 229 to define a cavity 235. The cavity 235 is adapted to receive a pin 237 therein. The pin 237 assists in preventing movement of the hard body relative to the side body.

A further difference Is that an outer edge 239 of each hard body has a recess 241 formed therein. When in position, recesses 241 of adjacent hard bodies 229 cooperate to provide a space into which material may accumulate. This material causes a force to be exerted upon the hard bodies 229, thus assisting to retain the hard bodies in place.

The second embodiment also differs from the first in that the outer surface 251 of the hard body 229 is curved, such that a portion of the outer surface 251 is proud of the surface 11 of the roller 10. The curved surface encourages retention of material in the center of the roller. It also improves the load bearing capability and reduces the likelihood of the edge of the hard bodies from breaking off as the profile redistributes the load away from the edge.

A third embodiment of the invention is shown in figures 16 and 17. For convenience features of the third embodiment that are similar or correspond to features of the first embodiment have been referenced with the same reference numerals.

The third embodiment differs from the first embodiment in that one or more of the hard bodies 329 is formed with a protrusion 335 in the surface which engages the side body 21. In this embodiment the side body 21 is formed with a complementary recess 333 (not shown) which, once the hard body 329 is in place, receives the protrusion 335 of the hard body. The co-operation of the protrusion 335 with the recess 333 assists in preventing movement of the hard body relative to the side body. The third embodiment also differs from the first in that an outer surface 331 of the hard body 329 is curved, such that a portion of the outer surface 331 Is proud of the surface 11 of the roller 10. The curved surface encourages retention of material in the center of the roller. It also improves the load bearing capability and reduces the likelihood of the edge of the hard bodies from breaking off as the profile redistributes the load away from the edge.

The multi piece edge protection assembly of the present Invention allows the edge protection to be reinstated regardless of whether the edge portion of the roller has worn. The side body containing the failed hard bodies is unbolted from the lateral face of the roller and a replacement side body reattached. Replacement of the hard bodies is therefore not dependant on the parent material of the roller securing the hard bodies remaining In original condition.

A multi piece edge protection assembly extends the window in which the edge can be reinstated allowing prompt rather than immediate replacement.

This design could dramatically extend the life and tonnage of the roller body. A fourth embodiment of the invention is shown in figures 18 to 22. For convenience features of the fourth embodiment that are similar or correspond to features of the first embodiment have been referenced with the same reference numerals.

In this embodiment the edge portion provides an annular recess 61. The annular recess 61 provides a side face 63 extending downwardly from the outer face 11 of the roller. The side face 63 is inclined inwardly from the outer face 11 towards the axis of the roller. In this embodiment the plurality of hard bodies 129 are received and secured in the annular recess 61 to provide the edge portion 119. Similar to the first embodiment, each hard body 129 has an inclined side face 143 complementary to and adapted to engage the inclined side face 63 of the recess 61.

As best shown in figure 21 the recess 61 has a thin section 65 extending thereacross. The thin section 65 is sufficiently thin to be flexed slightly outwardly when positioning the hard bodies 129 in position. The thin section also has a hole 67 which allows the dowel 45 to pass therethrough in order to secure the hard body 129 in position. The thin section 65 also places a downward force on the hard body 129, ensuring it is retained in engagement with the faces of the recess 61, which is particularly advantageous when inserting the dowel as well as whilst the glue between the hard body 129 and recess 61 dries.

Retaining the thin section on the roller by machining a recess into which the hard bodies are located creates a circumferential recess that is not open to the top but is open to the lateral face of the grinding roller. The thin section provides protection of the hard body upon start up of the machine whilst the semi autogenous layer Is being developed.

The hard body is further protected by the creation of a semi autogenous layer of crushed material due to the existence of the retaining hole for the dowel.

The thin section also protects and supports the insert 13. The material which may be comminuted by the pressure roller includes rock, ore, recyclable materials.

The present invention is not to be limited in scope by the specific embodiment described herein. The embodiment is intended for the purpose of exemplification only. Functionally equivalent products, elements and methods are clearly within the scope of the invention as described herein.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.