WO2005039776A1

WO2005039776A1 - A distributor plate

Info

Publication number: WO2005039776A1
Application number: PCT/AU2004/001464
Authority: WO
Inventors: Graham Strauss; Peter Hale
Original assignee: Crushing & Mining Equipment Pty Ltd
Priority date: 2003-10-23
Filing date: 2004-10-25
Publication date: 2005-05-06

Abstract

A distributor plate (10E) for an impelling rotor of a rotating shaft impactor, and its method of operation, is disclosed. The distributor plate (10E) is made up of a wear element in the form of metal carbide wear plate that is shaped as a thin circular disc (26E) which is positioned on and affixed to the upper surface of a distributor supporting body in the form of a base portion (28E). The disc (26E) covers the majority of an upper surface of the base portion (28E) onto which feed material would otherwise be received during use of the apparatus, to reduce undue wear of the base portion (26E). An upwardly projecting lipped flange (37E) that is positioned at the periphery of the base portion (28E), is arranged to contact the periphery of the circular disc (26E). The lipped flange (37E) is located as part of a circumferentially extending, integral arm portion (30E) of the base portion (28E) of the distributor plate (10E).

Description

A DISTRIBUTOR PLATE

Field of the Invention The present invention relates to the components of an impactor apparatus for breaking feed materials passed thereinto. In one form the invention relates to a feed distribution plate for use in a rotating shaft impactor and will primarily be described with reference to this context. However the components of the invention have broader use in feed distribution applications in other types of crushing or breaking.- equipment .

Background Art Impactors for breakage of materials are known in the art. • Such apparatus includes a rotating chamber, arranged to rapidly rotate about an axis. Feed materials such as rock, gravel, mineral ores and the like are passed into the rotor chamber via an inlet and contact a distributor plate located on one side of the chamber opposite to the feed material inlet. The materials are thus slowed from a finite to a nil axial velocity. The materials - then slide across the distributor plate with a finite radial velocity and are ejected sideways from the rotating chamber to impact against the surrounding walls of the impactor, and are thereby attritioned. A prior art arrangement of an impactor is shown in Figure 1, and is described in the co-pending Australian Patent Application 2002300428 to the present applicant. In this arrangement, a floor of the rotor chamber (which is generally made of an ordinary quality steel) is protected against wear by various shapes of cast alloy steel wear plates located thereon as well as the distributor plate itself. Referring to the part numbers used in Figure 1, a wear plate shown as 100 is seated on^' the chamber floor and is wedged or pinned into position nearest an exit port 300 located in a side wall of the rotor chamber 120. In plan view such a wear plate 100 is 5 generally triangular or trapezoidal in . shape, there usually being one such wear plate associated with each of the exit ports 300. Between each wear plate 100 and the distributor plate 10 is positioned an annular ring 200 of a cast material which encircles the plate 10 and abuts the 0 wear plates 100. In use, material is ejected from the chamber 120 by respectively sliding over the distributor plate 10, the annular ring 200 and the wear plate 100 before passing out through the ejection port 300. In further, embodiments, such wear plates can be arranged to

15 protect the roof of the chamber also. Figure 2 shows a detailed view of the prior art distributor plate and wear plate arrangement of Figure 1, giving more detail of the rotor floor and the rotatable shaft to which the rotor chamber is mounted.

20 Not every prior art impactor uses an annular ring of the type shown in Figures 1 and 2. .In some cases there is only a small space between the distributor plate and the floor wear plate,(s) , rather than an annular ring. In Figure 3 (where, for ease of reference, like parts to 2.5 previous embodiments of prior art apparatus are designated with like part^' numbers) an arrangement is shown in which material is ejected from the chamber by respectively sliding over the distributor plate 10 and. then the wear plate 100 before passing out through the ejection 'port .

30 Due to the nature of the feed materials and the duty required . of the apparatus, the distribution plate surface is normally made of a high strength material (such as tungsten carbide) overlaid on a less strong material such as mild steel; such plates are usually an expensive item. In use the distribution plates are ..subjected to

• significant and uneven wear from the impact and sliding movement of the feed material . However due to contact with abrasive materials, the wear plate 100 and annular ring 200 (typically made of low wear resistance cast metal) can develop very deep wear grooves necessitating more frequent replacement thereof. It is impractical from a cost and weight perspective to manufacture these components throughout of the same high strength material as the distributor plate surface. Replacement of these components first involves stopping the impactor and manually removing them. This - can be an awkward and difficult procedure with the distributor plate requiring removal before the annular ring 200 and the wear plate 100 can be accessed, leading to significant downtime of the impactor. There is also 'a significant risk of back strain or injury to the fingers of an operator in trying to prise these components apart because of jamming with fine dust and particulates trapped therebetween. A high- frequency of maintenance shutdown can be very costly from an operational standpoint.

Summary of the Invention In a first aspect the present invention provides a distributor plate for an impelling rotor of a rotating

• shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the distributor plate comprising: a supporting body; one or more wear elements positioned on the body to cover a surface of the body onto which the material would otherwise be received; and ^■5 - locating means for locating the wear element (s) on the body; wherein the or each wear element is arranged so that in use the material is ejected across the one or more wear members in a manner which minimises abrasive wear of the 10 said members . Such a wear element can reduce the severity of abrasive wear experienced by adjacent wear members (such as plates or an annular ring) , which are positioned to protect the floor of the rotor chamber^' against abrasion. The material 15 thus slides across the wear element and, rather than impacting directly upon the adjacent wear member (s), has a greater tendency to be proj ected thereover and out of the chamber thus prolonging the time before replacement of the wear member (s) is required. By being able to project feed

20 materials over the more easily worn surfaces, the influence of the wear element in the chamber is extended. The supporting body can be of any particular shape or thickness and is determinant of the position of the or each wear element within the chamber, for example what

25 distance the element/s are located above a base of the .chamber. In some embodiments, the or each wear element can be arranged in use to partially overlap the one or more wear members so as to cover a surface of said wear member (s)

30 which in use would otherwise be subjected to abrasive wear. In some embodiments,- a portion of the supporting body can also be arranged in use to partially overlap the one or more wear members . In some embodiments, the or each wear element can extend radially outwardly of a periphery of the body. In such embodiments, the locating means can comprise a projection from or adjacent either an opposing surface of the body or the wear element (s) . Such a projection can be -a lipped flange arranged outwardly of the periphery of the body. In one arrangement, the lipped flange can extend radially from and circumferentially about the body. In an alternative arrangement, a plurality of discrete lipped flanges are spaced around and arranged to extend radially from the body. In either of these arrangements the lipped flange can be defined by a first member and an orthogonal second member located at an end of the first member, the second member defining a lip and adapted .to engage with a periphery of■ the wear element . In further embodiments of the invention, the or each wear element can be located radially inwardly of a periphery of the body. In such embodiments, the locating means can comprise a projecting part of the body. In one arrangement, the projecting part can be a lipped flange arranged at the periphery of the body and adapted to be in contact with a periphery of the or each wear element . Such a lipped flange' can be circumferential about the body. In an alternative form, there can be a plurality of discrete lipped flanges that are spaced apart and arranged to extend circumferentially from the body. In a further embodiment where the or each wear element is located radially inwardly of a periphery of the body, the locating means can comprise an annulus which is seatable at a shoulder of the supporting body, the annulus having a projection thereat. In one form the projection can be a lipped flange arranged at the periphery.of the annulus and adapted to be in contact with a periphery of the or each wear element. The lipped flange may be circumferential about the annulus . In a further embodiment where the or each wear element is located radially inwardly of a periphery of the body, the locating^' means can comprise an extension arm member which is receivable in a shoulder recess of the supporting body, the extension arm member having a projection thereat. In an alternative arrangement, the locating means may comprise an extension arm member which is attachable to a -periphery of the supporting body, the extension arm member having a projection thereat. In either of these forms, the projection can be a lipped flange arranged at the periphery of the extension arm member and adapted to be in contact with a periphery of the or each wear element . In one embodiment there can be a plurality of discrete extension arm- members spaced circumferentially around to extend out from the supporting body. Furthermore, in any of these forms, the extension member may ^' be attachable to a periphery of the supporting body by a joining member insertable in aligned cavities formed in the supporting body and the extension arm member. For example, the joining member can be a pin. In a further embodiment where the or each wear element is located radially inwardly of a periphery of the body, the locating means can comprise a planar member which is seated on and covers the supporting body, the planar member having a projection thereat. In one form', the projection may be- a lipped flange arranged at the periphery of the planar member and adapted to be in contact with a periphery of the or each wear element . In an alternative form, a plurality of discrete projections can be spaced around and arranged about the periphery of ^• , the planar member, each adapted to be in contact with a periphery of the or each wear element . Furthermore, in any of these forms, the planar member may be attachable to the supporting body by one or more joining members insertable in aligned cavities formed in the supporting body and the planar member. For example, the joining member can be a pin. In any of the foregoing arrangements, the projection may solely or additionally comprise a pin arranged outwardly of one said surface of the or each wear element for receipt in a correspondingly-shaped cavity located in 'the body. Alternatively in any of the foregoing' arrangements, the projection may comprise one or more pins arranged outwardly of one said surface of the body each for receipt in a respective correspondingly-shaped cavity located in the or each wear element . As a further alternative, in any of the embodiments mentioned, the locating means may be an adhesive substance alone. In such an embodiment there is no requirement for any projection, pin, flange etc and the wear element/s are positioned directly on the body by an adhesive therebetween only. In one embodiment of the invention, the material contacting surface of the wear element can be substantially planar. A substantially flat or planar surface facilitates rapid and easy expulsion of material from the rotor chamber. The use of a substantially flat distributor plate also means that the centre of the rotor is less liable to blockage during use because the volume of available space in the rotor chamber is large enough to allow an easier passage . of higher volumes of feed material, or feed materials which have a coarser overall particle size. Nevertheless the invention is not limited to such forms of wear element or distributor plate shape. In any of the embodiments mentioned, an or said opposing surface of the or each wear element may be affixed to an or said opposing surface of the body. . In one form, the opposing surfaces are substantially planar. The or each wear element can be a plate. In one embodiment, there can be a single wear element that is in the form of a circular disc. The use of a single wear element reduces the incidence of the development of preferential wear sites at corners, edges, join lines- etc, which occurs with some distribution plates that have a two (or more) part surface . Typically the or each wear element is ^' made of a^" wear resistant material . In any of the foregoing embodiments of the distributor plate, the lipped flange(s) can be coated at, least in part with a wear resistant material. In some embodiments, the wear resistant material is a hard-facing material, and typically this hard-facing material may include tungsten carbide. It is desirable to have the lipped flange retain its original dimensions for as long as possible, up to and including the life of the wear element (s). There is normally a significant quantity of fine (and sometimes wet) abrasive material in the rotor chamber, which can cause significant wear to the exterior surface of a distributor plate, especially to the supporting body. Where an adhesive substance is located between the wear element and the supporting body, it is advantageous to prevent exposure of this substance to abrasive material. Such exposure potentially creates two problems. The abrasive action at the lipped flange may weaken the bond between the wear element and underlying supporting body. Also, inexperienced operators may see the discontinuity as a potential leverage point to prise up the distributor plate, an -action which can lead to separation of the wear element from the supporting .body. In any of the foregoing embodiments of the distributor plate, the or each wear element may be spaced from the body by one or more spacers arranged between opposing surfaces of the body and the wear element (s) so that, when the or each wear element is attached to the body by use of an adhesive substance, the spacer (s) provide for a predetermined depth of the adhesive substance between the body and the wear element (s) . The predetermined depth of an adhesive substance is typically the optimum amount of adhesive recommended by the adhesive manufacturer. In one form, one such spacer may be a projecting ring- on the body, concentric with a central axis of the body and inset from the periphery of the body. In any of the foregoing embodiments of the distributor plate, a peripheral edge of the body is bevelled in at least one position, the bevel adapted for the insertion of a levering tool to facilitate movement of the distributor plate. In some embodiments, the entire peripheral edge can be bevelled so that a levering tool such as a screwdriver can be inserted in any location on the circumference to facilitate lifting and grasping of the distributor plate by hand for rotation into a different wear position, or for servicing or replacement entirely. In any of the foregoing embodiments of the distributor plate, the impelling rotor can be mountable via a coupling element to a shaft of the impactor, wherein the distributor plate has a basal spigot with a cavity in the spigot for receiving the coupling element therein in use. - lO The cavity can be of any shape or dimension to suit the particular requirements of a coupling bolt or any other fastening device used to attach the rotor chamber to the shaft . In a second aspect the present invention provides an impelling rotor of a rotating shaft impactor including a .distributor plate as defined in the first aspect. In a third aspect the present invention provides a rotating shaft impactor including a distributor plate as defined in the first aspect. In a fourth aspect the present invention provides a method of operating a materials breakage apparatus comprising the steps of: introducing materials into a rotating chamber so as to impact the materials on a distributor plate located in the chamber; and passing the materials from the chamber by radially ejecting these materials through one or more ejection ports in the chamber wall; wherein said materials . are passed from the distributor plate to the ejection ports in a manner which minimises abrasive wear of wear members other than the distributor plate that are located in the chamber. Such a method of operation can reduce the severity of abrasive wear experienced by any wear members, which are located adjacent to the distributor plate and are positioned to protect the floor of the rotating chamber against abrasion. The materials slide across the distributor plate and, rather than impacting directly upon ^' the adjacent wear members, are largely projected thereover and out of the chamber via the ejection ports, thus prolonging the time before replacement of any wear member is required. Some embodiments of the method of the fourth aspect can employ the distributor plate^', impelling rotor and rotating ^' shaft impactor of the first, second and third aspects. In a fifth aspect, the present invention provides a method of forming a supporting body for a distributor plate comprising the steps of : coating a peripheral region of a supporting body at least in part with a wear resistant material; and - forming a recess over a central portion of the supporting body, the recess bounded by the peripheral region. This method can be- used as part of_. a method of forming a distributor plate, with the additional step of positioning one or more wear elements on the body and into the recess. In one embodiment, the method can further comprise the step of shaping a billet of material into the supporting body before the coating step. In an alternative embodiment, 'the method can further comprise the step of reshaping the supporting body after the coating step. In a sixth aspect the present invention provides a method of retrofitting one or more wear elements to a distributor plate for an impelling rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in . a side wall of the chamber, the method comprising the step of locating said one or more wear elements into position on the distributor plate to cover a surface thereof onto which the material would otherwise be received, at least some of the wear element (s) arranged so that in use the material is ejected ^' across the one or • more wear members in a manner which minimises abrasive wear of the said wear members . The • use of such wear element (s) can reduce the severity of abrasive wear experienced by adjacent wear members (such _.as plates or an annular ring) , which are positioned to protect the floor of the rotor chamber against abrasion. The material thus slides across the wear element and, rather than impacting directly upon the adjacent wear member (s), has a greater tendency to be projected thereover and out of the chamber thus prolonging the time before replacement of the wear member (s) is required. By being able to project feed materials over the more easily worn surfaces, the influence of the wear element in the chamber is extended, no matter what type of distributor plate is in use. By a simple retrofit of existing apparatus the present method can be implemented with a lower capital cost, which can obviate the possible reluctance in the marketplace to implementation of- a new method, for example if significant capital expenditure was needed to . change the type of distributor plate in use, in order to achieve the desired results. In this aspect, when referring to a distributor plate, this can include any type of distributor plate in common use, including those made of cast alloys or those made of a relatively soft material with exterior tungsten carbide plates, and of any shape, both flat-topped (eg Figures 1- 3) and conical-shaped (eg Figure 23) distributor plates being known types, as well ^■ as the distributor plate of the present invention (for those instances where repairs are needed) . In one embodiment, the method can comprise the step of positioning a wear element which is arranged in use to partially overlap the one or more wear members so as to cover a surface of said wear member (s) which in use would otherwise be subjected to abrasive wear. In another embodiment, the method can also comprise the step of fitting an extension portion to the distributor plate, the portion arranged in use to partially overlap the one or more wear members . Some embodiments of the method of the sixth aspect can employ the wear element of the first aspect . - In a seventh aspect, the present invention provides a retrofittable wear element for use in the method of the sixth aspect. In an eighth aspect, the present invention provides a distributor plate for an impelling rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the distributor plate comprising: a supporting body; one or more wear elements positioned on the body to cover a surface of the body onto which the material would otherwise be received; and locating means for locating the wear ^■ element (s) on the body; wherein a coating of a wear resistant material is arranged to protect locations where a join exists between any two of the supporting body, the wear element or the locating means so as to minimise abrasive wear at the said join. There is normally a significant quantity of fine (and sometimes wet) abrasive material in the rotor chamber, which can cause significant wear to the exterior surface of a distributor plate, especially to the supporting body. Where an adhesive substance is located between the wear element and the supporting body (or any other fastener pins etc) , it is advantageous to prevent exposure of this to abrasive material. Such exposure -potentially creates two problems . • The abrasive action may weaken the bond between the wear element and underlying supporting body. Also, inexperienced operators may see the discontinuity as a potential leverage point to prise up the distributor- plate, an action which can lead to separation of the wear element from the supporting body. Some embodiments of the distributor plate of the seventh - aspect can employ the supporting body, wear element, . locating means or wear resistant material of the first aspect . In a ninth aspect, the present invention provides an impelling rotor of a rotating shaft impactor including a distributor plate as defined in the eighth aspect. In a tenth aspect, the present invention provides a rotating shaft impactor including a distributor plate as defined in the eighth aspect . In an eleventh aspect, the present invention provides a method of forming a distributor plate for an impelling ^* rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received .therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the method comprising the steps of: locating one or more wear elements into position on the supporting body to cover a surface thereof onto which the material would - otherwise be received; and applying a coating of a wear resistant material so as to protect at least some locations where a join exists between the supporting body and the or each wear element so as to minimise abrasive wear at the said join(s) . Such a method of forming a distributor plate can lead to a product which will withstand wear to its exterior surface, especially to the supporting body, and to the join between the wear element and ,the supporting body. It is advantageous to prevent exposure of this joint to fine particle material because abrasive action at the join may weaken the bond between the wear element arid underlying supporting body. Also, inexperienced operators may see the discontinuity as a potential leverage point to prise up the distributor plate, an action which can lead to separation of the wear element from the supporting body. In one embodiment of this method, the coating can be applied circumferentially about the supporting body. In an embodiment, the method can further comprise the step of shaping a billet of material into the supporting body before the coating step. In another embodiment, the method can also comprise the step the step of reshaping the supporting body after the coating step.

Brief Description of the Drawings Notwithstanding any other forms which may fall within the scope of the present invention, some forms of the invention will now be described, by way of example only, with- reference to the accompanying drawings in which: Figure 1 shows a side sectional view of a prior art distributor plate fitted to an impelling rotor when assembled in a vertical shaft impactor machine. Figure 2 shows a detailed view of one part of the embodiment of Figure 1. Figure 3 shows a side sectional view of a prior art ■ distributor plate fitted to an impelling rotor when assembled in a vertical shaft impactor machine. Figure 4 shows a side sectional view of the embodiment of Figure 5 fitted to an impelling rotor when assembled in a vertical shaft impactor machine. Figure 5 shows an exploded side sectional view of one embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 6 shows an underside plan view of one embodiment of a distributor plate in accordance with the invention. Figure 7 shows a side sectional view of the embodiment of Figure 6 when shown along line 7-7. Figure 7A shows a detailed view of one part of the embodiment of Figure 7. Figure 8 shows an underside plan view of another embodiment of a distributor plate in accordance with the invention. Figure 9 shows a side sectional view of the embodiment of 'Figure 8 when shown along line 9-9. Figure 9A shows a detailed view of one part of the embodiment of Figure 9. Figure 10 shows a plan view of one embodiment of a support plate for supporting a distributor plate of an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 11 shows an exploded side sectional view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 12 shows a sectional side view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. . Figure 13 shows a sectional side view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 14 shows a sectional side view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 15 shows a sectional side view of a further

^■ embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 16 shows a top plan view of another embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 17 shows a sectional side view of the embodiment of Figure 16 when viewed along line 17-17. Figure 18 shows a top plan view of another embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 19 shows a sectional side view of the embodiment of Figure 18 when viewed along line 19-19. A wear element in the form of a circular disc is shown in phantom, and above its normal location at the top of the distributor plate. Figure 20 shows a top view of part of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. A wear element in the form of a circular disc 26H is omitted from this view for clarity. Figure 21 shows a side sectional view of the embodiment , of Figure 20 when shown along line 21-21 (and including the circular disc 26H) . Figure 22 shows a sectional side view of a further embodiment of 'a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 23 shows a side sectional view of a prior art distributor plate fitted to an impelling rotor of a vertical shaft impactor machine. Figure 24 shows a sectional side view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 25 shows a sectional side view of a further embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 26 shows a sectional side view of a series of steps leading to the formation of an embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 27 shows a sectional side view, of a series of steps leading to the formation of an embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 28 shows a sectional side view of a series of steps leading to the formation of an embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Figure 29 shows a sectional side view of a series of steps leading to the formation of an embodiment of a distributor plate for an impelling rotor of a vertical shaft impactor in accordance with the invention. Modes for Carrying out the Invention Referring to the drawings, a .number of embodiments will now be described of distributor plates in which the or each wear/ element part of the distributor plate is arranged so that in use the material is. ejected across the one or more adjacent wear members (such as annular rings or wear plates) in a manner which minimises abrasive wear of these wear members . In Figures 4 and 5, a distributor plate 10 is shown- for use in an impelling rotor of a vertical shaft impactor 14. Typically the impelling rotor is a chamber 12 having a circular top plate 16 and a bottom plate 18, with several support posts 20 located near the circumference of the plates 16, 18. The posts 20 join the top plate 16 to the bottom plate 18 and space the plates 16, 18 apart. The rotor chamber 12 is arranged to rotate about a vertical axis A-A. The posts 20 comprise discrete wall portions^' which have a generally elongate vertical and horizontal dimension, the space between these walls defining portals in the side wall of the chamber. In further embodiments the posts can be of any other shape or size dimension. During operation of the embodiment shown, feed materials for breakage are gravity-fed into the rotating chamber 12 via an entry port 22 located in the upper plate 16. Typical feed materials include rock, gravel, mineral ores, metalliferous slags, glass and the like. These relatively coarse materials pass into the rotor chamber 12 and contact or strike the rotating distributor plate 10 which is located at the base of the rotor chamber 12. The materials slide across the distributor plate 10 and are ejected radially^' out from the rotor chamber 12 through the spaces between the support posts 20, under centrifugal force. The materials impact the surrounding walls 21 of the impactor or wall-mounted anvils or other rocks located at or within the impactor walls 21, and are broken apart or attritioned. In further embodiments , of the invention the axis of rotation of the impelling rotor can be located on any angle from the vertical up to and including a horizontal axis. In any embodiment it is possible that the feed materials can be passed. into contact with the distributorplate by, for example, a pumping arrangement; the feed materials may therefore be suspended in a fluid, such as in a slurry, for example. Such a feeding arrangement may be more important in those embodiments of the invention where gravity-feeding of the apparatus alone is not .feasible. In some embodiments of the invention the impelling rotor can be open ended at the end which receives the feed materials and the "chamber" . portion is generally defined as a region adjacent the distributor plate which need not necessarily be enclosed by top and bottom plates. For example. in "hammer and anvil" type impactors the distributor plate is usually held in position by a lower peripheral lip thereon which • is interlocked underneath several "hammer" elements of a wear resistant material arranged around the perimeter of the distributor plate; in such apparatus the hammer elements are not necessarily connected to any circular top plate to define a rotor chamber . Typically the distributor plate 10 is removable for servicing, replacement etc. In the embodiment shown, the plate 10 has a substantially planar upper surface 24 onto which the feed materials are received. This one-piece, substantially flat surface 24 generally includes wear resistant materials and facilitates rapid and easy expulsion of feed materials from the rotor chamber 12. In a plan view the flat surface 24 shown is circular. In ^' further embodiments the upper surface of the distributor plate can be generally conical in shape, for example sloped radially downwardly from a peak height located at the centre of the distributor plate at the centreline A-A of the rotor. One typical - prior art arrangement of such a distributor plate is shown in Figure 23. The centre of such an embodiment of a distributor plate 10Q can include a . hole 41Q for placement of a centre bolt 42Q which fastens the distributor plate 10Q to the rotor body 18Q. In some embodiments, such a distributor plate 10Q can have a two or more part upper surface including a central conical portion 19Q and one or more, peripheral skirt portions 20Q joinable to the central conical portion 19Q, with the peripheral skirt portion (s) 20Q being more gently' sloped radially outwardly than the conical portion 19Q. In such devices the conical portion 19Q is inserted for protecting the centre bolt 42Q, and usually has at least an upper surface which includes wear resistant materials. The skirt portions are also generally made of a wear resistant material. The use of the substantially flat upper surface distributor plate 10 in the embodiment shown in Figures 4 and 5 can reduce the in use incidence of blockage at the centre of the rotor because the volume of available space in the rotor chamber is larger than that of other known rotors. Such less obstructive geometry can allow an easier passage of higher volumes of feed material, or feed materials which have a coarser overall particle size. Use of a single-piece upper surface of the distributor plate 10 can also have the advantage of reducing the incidence of preferential wear sites at corners,- edges, join lines etc, as can happen with the distribution plates that have two or more parts which form an upper surface thereof. Referring now to the embodiment shown in Figures 4, 5, 6, 7 and 7A, the upper surface 24 of the distributor plate 10 is defined by a wear element in the form of a wear plate 26 formed from a material, resistant to wear and abrasion, such as a metal carbide, for example, tungsten carbide, or indeed a sprayed carbide or a hard ceramic. However, the upper surface 24 may also be treated to be hardened. In such an instance a special hardening process can be carried out on the distributor plate upper surface 24 before it is placed into service. In further embodiments, the wear element need not be in the form of a single wear plate, but can be made up of a number of planar pieces or segments of hardened material which generally form one planar upper surface of the distributor plate. The cylindrical-shaped base portion 28 of the distributor plate 10 is typically made of a less expensive material, such as mild steel, although other typical examples can include aluminium, brass, high density polyethylene, or other hard plastics. In the embodiment shown in the drawings, the metal carbide wear plate 26 is in the form of a thin circular disc which is positioned on and affixed to the upper surface of a thicker distributor plate base portion 28. The wear plate 26 is positioned on the base portion 28 to cover an upper surface of the base portion 28 onto which feed material would otherwise be received during use of the apparatus, to reduce undue wear of the base material necessitating replacement of ^' the entire distributor plate 10. The wear plate 26 extends radially outwardly of the ■ periphery of the flat upper surface of the base portion 28, and is located thereon by an upwardly projecting lipped flange shown generally as 30._. The lipped flange extends radially outwardly and circumferentially around the base portion 28 of the distributor plate 10, and comprises a first plate member in the form of a flange 31 arranged orthogonally to the exterior side wall 35 of the base portion 28 and a second member defining an end lip 37, the end lip 37 arranged orthogonally to the flange 31 and located at the outermost end 39 of the flange. In one example the end lip. has a vertical height of around 15-20% of the depth of the wear- plate 26. As shown in the embodiment in Figure 1A, the flange 31 extends from the base portion 28 at a location flush with the upper edge of the exterior side wall 35 of that base portion 28. The wear plate 26 is thus seated over both the flange 31 and the base portion 28 and the lip 37 engages ^" with theperiphery of the wear plate 26. In a further embodiment of a distributor plate 10A shown in Figures 8, 9 and 9A, an upwardly projecting lip flange shown generally as 30A includes a first plate member in the form of a flange 31A which extends at an angle other than ninety angle degrees from the base portion 28 at a location which is not flush with the upper edge of the adjacent exterior side wall 35A of that base portion 28, but which extends out of the side of that exterior side wall 35A. The wear plate 26A is thus not seated at the flange 31A, however in this embodiment the lip 37 is still in engagement with the periphery of the wear plate 26A. In other embodiments the lipped flange may only be arranged partially about the circumference of the wear element, for example comprising only two or three discrete protruding flanges in the form of strips which extend from the base portion 28, each strip with an end lip. In such an embodiment the strips are spaced apart and extend radially from the base portion 28. The end lip of each strip is arranged to still be in engagement with the periphery of the wear plate in order to locate that plate in a seated position on the base portion 28. In other embodiments, the wear plate (such as circular disc 26) can be held in position by one or more projections from the underside of the circular disc being the side which is located adjacent to the base portion 28 in use. As shown in Figure 12, the projection (s) can be a single projecting rim 29, or in other embodiments can be a number of discrete projecting tabs or pins, for example, formed or fitted so that when the circular disc is seated at the base portion, the rim 29 or projecting tabs or pins are located in abutment and engagement with the exterior side wall 35 of the base portion to locate that circular, disc 26 on the base portion 28. By extending the wear plate (s) radially outwardly of the periphery of the base portion, this allows an overlap of the rotor floor wear plates 100 or the annular ring 200 (if these are present) , which are positioned to protect the floor (bottom plate 18) ^• of the rotor chamber 12 against abrasion. A reduction can be achieved in the severity of abrasive wear experienced by these wear plates. Material fed to the chamber slides across the wear plate 26 of the distributor plate 10 and, rather than impacting directly upon the adjacent rotor floor protective wear plate (s) 100 or annular ring 200 during exit from the chamber 12, the material .has a greater tendency to be projected thereover and out of the chamber 12. This prolongs the time before replacement of the rotor floor wear plates 100 or ring 200 is required, and therefore can reduce operational costs. Because of the outward radial extension of the wear element, in some circumstances the ring 200 may even be able to be dispensed with entirely. It is within the scope of the invention for the outward radial extension of the wear plate to be of any width compared with the diameter of the base portion, but in one embodiment, the • wear plate 26 has a 10-20% wider diameter than that of the base portion 28. In other embodiments the wear plate can be of a shape other than the circular version shown in the Figures . For example, the wear plate shape can be square, triangular, hexagonal or even irregular in shape provided that the plate extends at least partly beyond the periphery of the base portion at which it is seated. Also, the wear plate does not need to be the same shape as the base portion. Further embodiments will now be described where the or each wear plate is located radially inwardly of a periphery of the base portion. By having the wear plate (s) radially inwardly of the periphery of the base portion, in some embodiments this allows at least parts of the wear plate of the^' distributor plate to overlap the rotor floor wear plates 100 or the annular ring 200 (if these are present) , which are positioned to protect the floor (bottom plate 18) of the rotor chamber 12 against abrasion. In other embodiments which will now be described, overlaid parts of the wear plates and the base portion can both overlap -the rotor floor wear plates. Similarly to previous embodiments described, as a result of this overlap, a reduction can be achieved in the severity of abrasive wear experienced by these floor wear plates 100, 200. Referring now to Figure 14 the upper surface of the distributor plate 10E is defined by a wear element in the form of metal carbide wear plate that is shaped as a thin circular disc 26E which is positioned on and affixed to the upper surface of a supporting body in the form of a base portion 28E. The disc 26E covers the majority of an upper surface of the base portion 28E onto which feed material would otherwise be received during _ use of the apparatus, to reduce undue wear of the base portion 26E necessitating replacement of the entire distributor plate 10E. The circular disc 26E extends radially inwardly of the periphery of the flat upper surface of the base portion 28E, and is located thereon by an^' upwardly projecting lipped flange 37E that is positioned at the periphery of the base, portion 28E and is arranged to contact the periphery of the circular disc 26E. The lipped flange 37E is located as part of a circumferentially extending, integral arm portion 30E of the base portion 28E of the distributor plate 10E, and is located at the outermost end 39E of the arm portion 30E. The . wear plate 26E is thus seated over both the arm portion 30E and the remainder of the base portion 28Ξ . and the lip 37E engages with the periphery of the circular disc 26E. As shown in Figure 14, the arm portion 30E is arranged to overlap at least part of the floor mounted wear plates 100E. In a further alternative arrangement shown in Figure 15, the integral arm portion 30D of the wear plate 10D can extend only partially over the distributor ring 200D. In other embodiments, instead of a circumferential, integral arm portion extending from the base portion of the distributor plate, there can be a plurality of discrete arm portions that are spaced apart and arranged to extend circumferentially from the base portion. Referring now to Figures 16 and 17, a further embodiment is shown where the or each wear plate is located radially inwardly of a periphery of the base portion of the distributor plate. In Figure 16 the upper surface of the distributor plate 10F is defined by a wear element in the form of metal carbide wear plate that is shaped as a thin circular disc 26F which is positioned on and affixed to the upper surface of a distributor supporting body in the form of a base portion- 28F. The disc 26F covers the

- majority of an upper surface of the base portion 28F onto which feed material would otherwise be received during use of the apparatus . The circular disc 26F is located on the base portion 28F by an upwardly projecting lipped flange 37F that is positioned at one peripheral edge of an annulus 4OF, the lipped flange 37F arranged to contact the periphery of the circular disc 26F. The lipped flange 37F is integrally formed as part of the annulus 4OF, and the annulus 4OF itself is seated at a shoulder 42F formed as a recess in the base portion 28F. The circular disc 26F is thus seated over both the annulus 4OF and the base portion 28F, and the lip 37F engages with the periphery of the circular . disc 26F. Typically the annulus 4OF can be attached to the base portion 28F by any technique, such as plug, stitch or continuous welding, or even attachment by gluing or fasteners such as screws. This apparatus has the advantage of being able to re-use the base portion 28F. When the circular disc 26F and/or the lipped flange 37F become worn, these components can be removed from the base portion 28F and a hew annulus 40F and/or circular disc 26F can be fitted thereto by - any of the aforementioned welding, screwing or gluing techniques. In other embodiments, instead of an annulus which is circumferential and extending fully about the base portion so as to extend from the base portion of the distributor plate, there can be a plurality of discrete arm portions that are spaced apart and arranged to extend from shoulder recesses in the base portion. As shown in Figures 18 and 19, each arm member 40G is seated at a shoulder 42G formed as a recess in the base portion 28G. In this embodiment, wear plate 26G is . thus seated over each arm member 40G as well as the base portion 28G, and the lip 37G at the outer periphery of each arm member 40G engages with the periphery of the circular disc 26G. In this embodiment, in use, some peripheral regions of the circular disc 26G (between the arm members 40G) extend over an- adjacent floor wear member 100, 200, whereas as those same regions, parts of the base portion 28G do not do so. This apparatus also has the advantage of being able to re-use the base portion 28G when the lip 37G on each arm member 40G becomes too badly worn, or the circular disc 26G is due for replacement . ' In a further alternative arrangement shown in Figures 20 and 21, a plurality of extension arm members 4OH are attached to a periphery of the base portion 28H. Each arm member 4OH thus extends from an exterior wall 29H of the base portion 28H, and is fastened to that wall, rather than being seated in any recess etc, as shown in the embodiment in Figures 18 and 19. In this arrangement, there can be a plurality of discrete arm members 4OH that are spaced apart and arranged to be joined to the base portion 28H by, in this instance, two joining pins 31H insertable in aligned cavities formed in the base portion 28H arid the extension arm members 4OH. In this embodiment, a circular disc 26H can be seated over each - arm member OH as well as the base portion 28H, and the lip 37H at the outer periphery of each arm member .4OH engages with the periphery of the circular disc 26H. This apparatus also has the advantage of being able to re-use the base portion 28H when the lip 37H on each arm member 40H becomes too badly worn, or the circular disc 26H is due for replacement . In a further alternative arrangement shown in Figure 22, the locating means is in the form of a planar disc 44J which is seated on and covers the base portion 28J. The planar disc has a projection in the form of an orthogonal, peripheral rim 37J arranged at the periphery of the planar disc 44J. The rim 37J is adapted to be in contact with a periphery of the wear element in the form of circular disc 26J. The planar disc 44J is attached to the base portion 28J by two pins 31J that are accommodated in cavities machined in both the disc 44J itself and the portion 28J. In this embodiment, the circular disc 26H is seated over the entire planar disc 44J, and the disc can- overlap an adjacent floor wear member 100, 200. This apparatus also has the advantage' of being able to re-use the base portion 28J when the lip 37J on the planar disc 44J becomes too badly worn, or the circular disc 26J is due for replacement . In the embodiments shown in Figures 14-22, the projection shown in each example is an orthogonal rim or lipped flange having some elongate dimension, however in further embodiments the projection can be non-continuous rim, or a series of spikes, tabs or other shape of protrusion which is arranged at a periphery of the extension arm member and is adapted to contact a. periphery of the .or each wear element, (shown in these embodiments as a planar circular disc 26, but can be any other shape of wear plate) .. In any of the embodiments shown in Figures 4-22, in order to have the lipped flange 37 (37A, D, J etc) retain its original dimensions for as long as possible, up to and including the life of the wear element (s), the lipped flange 37 can be coated at least in^' part with a wear resistant material. In some applications, for maximum wear resistant effect, a welded matrix including tungsten ' carbide hard-facing, particulates can be applied to the lipped flange 37 .to increase the wear resistance of- the flange, especially if such a flange is made of a relative soft material such as mild steel. Typically such a welded matrix is applied to the base portion 28 (28A, D, J etc) , (or to the annulus 40F or- arm member 40G etc) prior to any machining of a seat for the circular disc 26 wear element, for example. This is so there is no heat distortion of the supporting base seat for the circular disc 26, so that the adhesive used to attach the circular disc 26 can be of an even thickness. Figure 26 shows an example of the positioning of a welded matrix at the peripheral edge of a typical base portion 28L. In that Figure, the welded matrix 70 is applied over the entire peripheral edge of the base portion, down to the bevelled region 36. In some other embodiments, for example as shown in Figure 27, only the immediate area of the lipped flange 37K is coated with a wear resistant material 72. In both cases, the effect of the hard-facing material is such that the peripheral lipped flange 37 is protected and any adhesive substance that is . located between the wear element 26 and the supporting body 28L is protected from exposure to abrasive material. The typical stages in the manufacture of a distributor plate having a base portion made of mild steel that is also hard faced are shown in Figure 26. In this example, a mild steel billet 74 (Step A) is machined in Step B to 5 produce a preliminary base portion 76 to be used to support a circular disc 26 to act as a wear plate. The preliminary base portion 76 includes a lower bevelled edge 36 and basal spigot 38 with internal recess. In Step C, tungsten hard facing 70 is applied to the outer peripheral

10 edge of the preliminary base portion 76. In Step D, a recessed seat for the circular disc 26 is machined . from the top of the preliminary base portion 76, leaving behind an upwardly oriented ring 32, which determines the glue thickness that will be used when adhering the circular

15 disc to the base portion 28 . In the final Step E, the circular disc 26 is glued into the recessed seat of the base portion 28L. In ari alternative final step, any shape of wear element can be placed into the recessed seat of the base portion,

20 and, for example, in Step F, a thicker, sloping-top wear plate 78 is shown fitted to the base portion 28L, the wear plate 78 having an overhanging portion 81 which can further overlap with, and thus direct material for breakage over, the rotor floor wear plates 100, 200.

25 A further embodiment of the typical stages in the manufacture of a distributor plate having a base portion made of mild steel to be hard faced are shown in Figure 27. In this example, a mild steel billet 74 (Step A) is machined in Step G to produce a preliminary base portion

,30 83 to be used to support a circular disc 26 to act as a wear plate. The preliminary base portion 83 includes a basal spigot 38 with internal recess. In Step H, tungsten hard facing 72 is applied to the outer peripheral edge of the preliminary base portion 83. In Step J, the base of the_. preliminary base portion 83 is machined to shape out - .an integral arm portion 85. Then in Step K a recessed seat for the circular disc 26 is machined from the top of the preliminary base portion 83, leaving behind an upwardly oriented, ring 32, which determines the glue thickness that will be used when adhering the circular disc to the base portion 28M. In the final Step L, the circular^' disc 26 is glued into the recessed seat of the base portion 28M. Further embodiments of the use of hard-facing materials are given in Figures 28 and 29. In both of these embodiments, a mild steel billet 74 (Step A) is machined in Step B to produce a preliminary base portion 76 to be used to support a circular disc 26 to act as a wear plate. The preliminary base portion 76 includes a lower bevelled edge 36 and basal spigot 38 with an internal .recess. In Step M, a seat for the circular disc 26 is machined evenly across the top surface of the preliminary base portion 76, only leaving behind an upwardly oriented ring 32, which determines the glue thickness that will be used when adhering the circular disc to the base portion 28N. Referring to Figure 28, in Step N a circular disc 26 is glued onto the base portion 28N. Then in Step P, a tungsten hard facing 87 is ^' applied to the outer peripheral edge of both the base portion 28N and the circular disc 26 to protect the location where the join exists between the circular disc 26 and the base portion 28N. This hard- facing is to prevent erosive wear of the relatively softer material of the base portion 28N, the adhesive substance, or any other fastening pins located at the join, which could lead to failure or break-up- of the distributor plate during operation. In Figure 29, Steps B and M are as described for Figure

28. In Step Q, a thicker, flat-topped wear plate 91 is glued into place onto base portion 28N. Wear plate 91 hasan integral overhanging portion 93 which can further overlap with, and thus direct material for breakage over, the rotor floor wear plates 100, 200. Then in Step R, a tungsten hard facing 97 is applied to the outer peripheral edge of the base portion 28N and to the outer peripheral side of the wear plate 91 to protect the location where the join exists between the wear plate 91 and the base portion 28N. This hard-facing is also to prevent erosive wear of the relatively softer material of the base portion 28N, the adhesive substance, or any other fastening pins located at the join, which could lead to failure of the distributor plate during operation. Furthermore, the method of applying hard-facing to a join between two parts of the distributor plate is applicable to other shapes of wear elements, with or without overlap of the rotor floor wear plates, .as long as these distributor plate wear elements are arranged to eject materials from the rotor so as to reduce the incidence of erosion of the floor-mounted wear elements . In further embodiments, any of the wear plate positioning methods previously described for those distributor plates where the wear plate (s) extend radially outwardly beyond the periphery of the base portion (such as the use of projections from the underside of the wear plate which are insertable in aligned cavities etc) can also be used in conjunction with any of the embodiments now described where the wear plate (s) are located radially inwardly of a periphery of the base portion. Also, while it is within the scope of the invention for the wear plate circular disc 26 to be of any width compared with the diameter of the base .portion 28, it is generally better if the circular disc 26 extends sufficiently to contact the peripheral projections of the annulus 4OF, extension arms 40G, integral arm 30D, etc. in order to locate that circular disc 26 in a seated position on the base portion 28. In other embodiments of the invention the or each wear element of the distributor plate need not be a single, flat plate, but instead of the type where the distributor plate is overall conical in shape, eg. the distributor plate has a base portion fitted with two or more upper surface parts including, for example, a central conical portion and one or more sloped skirt pieces joinable to the central conical portion, as shown in Figure 23. In such a known arrangement, the skirt piece (s) extend only to the periphery of the base portion so that material leaving the chamber is projected off the distributor plate and onto the adjacent rotor floor protective wear plate (s) 100 or ring 200, as previously described. Such known apparatus can be retrofitted in order to reduce the sliding of material across the rotor floor wear plates 100, 200. For example, as shown in Figure 24, external skirt pieces 21Q of a hard-wearing material can be positioned at the upper exterior surface of the sloped peripheral skirt portions 20Q of the known prior art distributor plate 10Q to assist the projection of material thereover and out of the rotor chamber. As shown in Figure 24, the hard-wearing material pieces 21Q partially overlap the annular ring 200 at 23Q. A further embodiment of a retrofitting application of the invention is shown in Figure 25. A lateral, circumferential extension ring 25Q is fitted around the periphery of the known prior art distributor plate 10Q by welding or gluing, and ^{ the extension ring 25Q is then fitted with one or more pieces of hard-wearing material 27Q. The extension ring 25Q fitted with an upper exterior surface of hard-wearing material 27Q can assist the projection of feed ore materials thereover and out of the rotor chamber, thus reducing the incidence of impact or abrasive wear on the rotor floor-mounted wear plates . As shown in Figure 25, the extension ring 25Q is arranged to partially overlap the floor-mounted wear plates 100, and no annular ring 200 is present, or necessary. In either of the arrangements shown in Figures 24 and 25, the skirt piece (s) can be held in position by one or more upwardly oriented projections from ^• the base portion of the distributor plate to engage with an outer peripheral edge of the skirt piece (s) 21Q, 27Q, or alternatively, the skirt piece (s) 21Q, 27Q can be formed or fitted with a number of discrete projecting tabs or pins which in use can be located adjacent the exterior side wall of the base portion so as to locate the piece (s) in a seated position on the base portion. Any type or. shape of wear element to be retrofitted to a known distributor plate is within the scope of the present invention. In further embodiments of the distributor plate of the invention, with any type of wear element (eg. a single, .flat plate, or having two or more upper surface parts, eg a central conical portion) , one or more projections from either an opposing surface of the base portion (such as 28) or from the wear plate (s) can be used for locating the wear plate (s) on the base portion. In one arrangement, the projection (s) can be in the form of one or more discrete pins formed or fitted in any position to . the underside of the or each wear plate so that when each plate is seated at the base portion, the projecting pins are each received in a correspondingly-shaped cavity located in the abutting face of the base portion so as to locate the wear plate on the base portion. In a further alternative arrangement, the projections can be in the form of one or more discrete pins formed or fitted to the upper side of the base portion for receipt in a correspondingly-shaped cavity located in the underside of the or each wear plate. In another further alternative arrangement, the projections can be in the form of one or more separate pins that can be seated in respective opposingly aligned ^"cavities or sockets located in both the upper side of the base portion and in the underside of the or each wear plate to fix the position of the adjoining base portion and wear plate (s) relative to each other. Any type of locating means is within the scope of the invention to retain the wear plate on the upper surface of the base portion of the distributor plate. For example, in the embodiment shown in Figure 13 , the locating means . can be in the form of an adhesive substance 33 alone, located in the gap 39 between the circular disc 26 and the base portion 28. In such an embodiment there is no requirement for any projection, lip wall, pin, flange etc and the wear element/s are positioned directly on the body with an adhesive therebetween only. Wear element (s) can be fasteningly located upside down in a gluing jig and the base portion of the distributor plate placed thereonto after application of the adhesive onto the underside of the wear element _; In some further embodiments of the invention an adhesive substance is not required to join the wear plate to the distributor plate base portion, and there is no requirement for there to be spacing rings (or any other surface projections) on the upper surface of the base portion or on the lower surface of the wear plate. In such examples the wear plate can be spray-applied, welded, brazed or otherwise fused to the distributor plate base portion so that there is a direct bond between the adjacent surfaces of the- wear plate and the base portion. In still further embodiments, any combination of any of the described types of locating means is within the scope of the invention to retain the wear plate on the upper surface of the base portion of the distributor plate. In still further embodiments, the base portion need not have a flat upper surface for the wear plate to be seated thereon. For example, the base portion may have a slight conical shape (either convex or concave) to be mated with a corresponding shape on the underside of the wear plate . In any of these examples, the upper surface of the wear plate can still be provided with a substantially planar or flat upper surface so that the distributor plate has a substantially planar upper surface in use. In the embodiment shown in at least some of Figures 4-22, - when mounting the respective wear plates in the form of circular disc 26 (A, D, J etc) on the base portion 28 (A, D, J etc) to form a distributor plate 10 (A, D-, J etc) , the circular disc 26 typically being spaced from the base portion 28 by a spacing means in the form of an, upwardly oriented ring 32 located on or formed at the upper surface of base portion 28. The ring 32 is concentric about the centre of the distribution plate 10 located at the vertical axis A-A and is inset from the peripheral edge 34 of the base portion 28. More than one ring can be employed on the upper surface of the base portion and typically the ring(s) 32 are around 0.5mm in height. The ring 32 provides for a predetermined depth of an adhesive substance 33 which is used in the distributor plate assembly process to join the base portion 28 and the circular disc 26, the depth typically for the optimum amount of adhesive being as recommended by the adhesive manufacturer.

5. In further embodiments of -the invention the spacing ring(s) may only comprise a partial ring, or perhaps only several spaced apart upwardly oriented surface projections (e.g. dimples) located on the upper surface of the base portion. Alternatively, the ring may be located on an0 underside of the wear plate (s). Any type of spacer that provides a predetermined depth of an adhesive substance to retain the wear plate (s) on the upper surface of the base portion of the distributor plate is within the scope of the invention. (5 Depending upon the diameter of the distributor plate and the thickness and diameter of the wear plate, the distributor plate can be quite heavy and cumbersome to manipulate,^' requiring the use of a levering tool, or perhaps even a number of tools used simultaneously and 0 spaced around the plate 10. Referring to Figures 4, 6, 11, 12, 13, 14 and 15 with respective reference to the distributor plates numbered 10 (and 10A, B, C etc) , the lower peripheral edge of the base portion of the distributor plate 10 is typically bevelled5 in at least one position 36, so that a levering tool such as a screwdriver can be inserted to facilitate lifting and grasping of the distributor plate 10 by hand for rotation into a different wear position, or for servicing or replacement entirely. In one embodiment the entire lower 0 peripheral edge is bevelled. Alternatively, a number of discrete bevelled portions in the ^• lowermost peripheral edge of the distributor plate can be employed. In one embodiment, for example as shown in Figure 5 , the distributor plate 10 has a basal spigot 38 extending from a lowermost portion of the base portion 28 and provided with a downwardly facing cavity 40. The cavity 40 is arranged to receive a coupling bolt 42 therein when the plate 10 is mounted in chamber 12. The coupling bolt is used to fasten the bottom plate 18 of the chamber 12 (or other member linked to the bottom plate 18) to a rotatable vertical shaft 4 ■ of the vertical shaft impactor 14. The cavity 40 in the spigot 38 can be of any shape or dimension to suit the particular requirements of a coupling bolt 42 or any other fastening device used to attach the chamber 12 to the shaft 44. In some examples where the chamber 12 is fastened to the shaft by another fastening arrangement other than a central coupling bolt, the cavity 40 in the spigot 38 may not be required to accommodate a fastening device and may in fact be empty when in use. The spigot 38 can be of any suitable outer shape, and in one embodiment shown is a hexagonal prism shape. Referring to any of Figures 4 to 22, where like reference numerals are used to denote similar or like parts, it will be seen that- circular discs 26 and base portions 28 of varying thicknesses can be employed. For example, an overall thinner wear plate can be used for less abrasive or lighter feed materials. Referring in particular to Figures 5, 10, 14 and 15, a support plate 50 is used in the vertical shaft impactor 14 to support the distributor plate 10. The support plate has a multi-sided central recess 52 (in this case, a through-hole) for the insertion thereinto of the., multi- sided basal spigot 38. The number of sides of the hole 52 in the support plate 50 is typically defined to be a multiple of the number of sides of the spigot 38. In one embodiment, the hole in the support plate is a polygon with, in effect, twenty four "sides" (being a twelve pointed star shape) . The basal spigot 38 has six sides, and has a hexagonal prism shape. In one embodiment, where there are three posts 20 in the impactor rotor chamber 12 (and therefore three spaces between the support posts 20 from which feed materials may be radially ejected from the spinning rotor chamber 12) , it is possible to move (rotate) the distributor plate 10 with respect ^"to the support plate 50 into four different "wear" positions, to spread the abrasive wearing of the metal carbide^" evenly over the wear plate 26 over time, rather than only having a limited number of grooves worn into the wear plate 26. The number of possible wear positions can thus be determined by the number of polygonal corner points or star tips of the hole in the support plate 50 divided by the number of material outlet spaces from the rotor chamber 12. For example, in the instance where a six sided polygonal hole in the support plate receives a six sided basal spigot, in a chamber where there are three feed outlet spaces, the distributor plates is only moveable into two "wear" positions, which is rather limited. Having polygonal holes in the support plate of, say, 9, 12 or 15 sides means that, in a rotor chamber utilising three outlet spaces between support posts, there are 3, 4 or 5 respective possible wear positions for the distributor plate 10 to be moved into. It is also possible to produce rotor chambers having 3, 4, 5 or even 6 outlet spaces. Figure 10 also shows a number of recessed bolt holes 54 in the -support plate 50 which are used to attach the plate 50 via bolts 56 (Figure 5) to a boss 58. The boss 58 is located to surround an upper end of the vertical shaft 44 on which the rotor body 12 sits (Figure 5) , and can also be attached to the base plate 18 of the rotor body 12 itself. The boss 58 has a tapered hole 60 to match a corresponding taper on the vertical shaft 44. Any number, array or position of recessed bolt holes 54 for attaching the support plate 50 to the boss is within the scope of the present invention. This plate provides axial and rotational support for the distributor plate in the rotor chamber. In other embodiments the distributor plate can also be attached to any part of the rotating impactor assembly including base 18 by the use of bolts for receipt into corresponding holes in the base, or any other joining mechanism. Other joining plate types are within the scope of the invention and the particular arrangements illustrated in Figure 5 and Figure 10 are only one way of attaching the support plate and rotor body to the rotatable shaft to permit high speed rotational operation.. In still further embodiments, the distributor plate

10 can be attached directly to the shaft 44 of the rotor which rotates about vertical axis A-A. Referring to Figure 11, where like reference numerals are used to denote similar or like parts used in previous embodiments, the rotor shaft 44 itself can have a multi-sided central recess 80 for the insertion thereinto of the multi-sided basal spigot 38 of the distributor plate 10. Once again the number of sides of the recess 80 in the shaft 44 is typically defined to be a multiple of the number of sides of the spigot 38. In one embodiment, the recess 80 in the shaft can be a polygon with, in effect, twenty four "sides" (being a twelve pointed star shape) to be used with a basal spigot 38 with six sides, and of a hexagonal prism shape. Figure 11 also shows a number of recessed bolt holes 82 in the bottom plate 18 which can be used to attach this plate via bolts 84 to a boss 86. Boss 86 is located to surround an upper end of the vertical shaft 44 on which the base plate 18 of the rotor body 12 sits. Any number, array or position of recessed bolt holes 82 for receiving bolts 84 to attach the base plate 18 to boss 86 is within the scope of the present invention. Furthermore the boss ^' 86 can be attached to the vertical shaft 44 by means of a taper lock device 88 fitted about the shaft 44. Any

• device for joining the boss to the shaft and the base plate of the rotor body to the boss are within the scope of the invention and the particular arrangements illustrated in Figure 11 are only one example. In further embodiments, grub screws or external clips, for example, can be used to join the component parts together. In use the distributor plate can be moved into various wear positions (as held by the support plate or the rotor itself) by an operator to minimise the uneven nature of wear of the metal carbide which is used in the wear plate, shown in the form of circular disc 26. In turn such a facility enables thin metal carbide wear plates to be used in such apparatus (see e.g. Figures 7, 7A and Figures 9, 9A) which reduces the unit cost and weight of the distributor plates. The use of a distributor plate with a basal spigot to "fasten" the distributor plate into the rotor chamber 12 eliminates the need to have a central axial fastening bolt in the top of the distribution plate. Such a bolt is an adverse feature of known apparatus, for example shown in the prior art arrangement of Figure 23,- which normally necessitates a conical or peaked cap (such as 19Q) of metal carbide being placed over the central fastening bolt after fitting during use of the impactor rotor. In such known apparatus, uneven wearing due to some slight dislodgement of a prior art metal carbide cap 19Q, in addition to the blocking of the rotor chamber itself with feed materials, can commonly be the result . The performance and maintenance requirements of impactors are affected by the cost of parts and how frequently they have to be changed. A reduced frequency of servicing and maintenance intervals combined with safer and easier changing of impactor machine parts and a lower consumption of expensive, wear resistant materials used in the floor area^{' '}of the chamber can lead to lower materials processing costs overall. The present invention outlines several embodiments that can enable an operator of a rotating shaft impactor to pass materials into and out of such a device, and, depending on the particle size, material type and hardness, and the duty required of the impactor, to arrange the apparatus in such a manner that reduces the abrasion experienced by rotor wear members . The materials of construction of the distributor plate and the support plate can be any suitable materials which wear appropriately and that can be shaped, formed and fitted in the manners so described, such as the appropriate metal, metal alloys, ceramics or plastics etc, referred to already. The support plate does not need to be especially hardened or be made of very strong materials and can be formed from lighter weight metals such as aluminium or hard plastics and the like. It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms a part of the common general knowledge in the art, in Australia or any other country. - Whilst the invention has been . described with reference to some embodiments it should be appreciated that the invention can be embodied in many other forms.

Claims

1. A distributor plate for an impelling rotor of a rotating shaft impactor, ' where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the distributor plate comprising: a supporting body; one or more wear elements positioned on the body to cover a surface of the body onto which the material would otherwise be received; and locating means for locating the wear element (s) on the body; wherein the or each wear element is arranged so that in use the material is ejected across the one or more wear members in a manner which minimises abrasive wear of the said members .

2. A distributor plate as claimed in • claim 1 wherein the or each wear element is arranged in use to partially overlap the one or more wear members so as to cover a surface of said wear member (s) which in use would otherwise be subjected to abrasive wear.

3. A distributor plate as claimed in claim 2 wherein a portion of the supporting body is also arranged in use to partially overlap the one or more wear me bers.

4. A distributor plate as claimed in any one of the preceding^' claims wherein the or each wear element extends radially outwardly of a periphery of the body.

5. A distributor plate as claimed in claim 4 wherein the locating means comprises a projection from or adjacent either an opposing surface of the body or the wear element (s) .

6. A distributor plate as claimed in claim 5 wherein the projection is a lipped flange arranged outwardly of the periphery of the body.

7. A distributor plate as claimed in claim 6 wherein the lipped flange extends radially from and circumferentially about the body.

8. A distributor plate as claimed in claim 6 wherein a plurality of discrete lipped flanges are spaced around and arranged to extend radially from the body.

9. A distributor plate as claimed in claim 7 or claim 8 wherein the lipped flange is defined by a first member and an orthogonal second member located at an end of the first member, the second member defining a lip and adapted to engage with a periphery of the wear element.

10. A distributor plate as claimed in any one of claims 1 to 3 wherein the or each wear element is located radially inwardly of a periphery of the body.

-11. A distributor plate as claimed in claim 10 wherein the locating means comprises a projecting part of the body.

12. A distributor plate as claimed in claim 11 wherein the projecting part is a lipped flange arranged at the periphery of the body and adapted to be in contact with a periphery of the or each wear element .

13. A distributor plate as claimed in claim 12 wherein the lipped flange is circumferential about the body.

14. A distributor plate as claimed in claim 12 wherein a plurality of discrete lipped flanges are spaced apart and arranged to extend circumferentially from the body.

15. A distributor plate as claimed in claim 10 wherein the locating means comprises an annulus ' which is seatable at a shoulder of the supporting body, the annulus having a projection thereat..

16. A distributor plate as claimed in claim 15 wherein the projection is a lipped flange arranged at the periphery of the annulus and adapted to be in contact with a periphery of the or each wear element .

17. A distributor plate as claimed in claim 16 wherein the lipped flange is circumferential about the annulus.

18. A distributor plate as claimed in claim 10 wherein the locating means comprises an extension arm member which is receivable in a shoulder recess of the -supporting body, the extension arm member having a projection thereat.

19. A distributor plate as claimed in claim 10 wherein the locating means comprises an extension arm member which is attachable to a periphery of the supporting body, the extension arm member having a- projection thereat.

20. A distributor plate as claimed in claim 18 or claim 19 wherein the projection is a lipped flange arranged at the periphery of the extension arm member and adapted to be in contact with a periphery of the or each wear element .

21. A distributor plate as claimed in claim 20 wherein a plurality of discrete extension arm members spaced •circumferentially around to extend out from the supporting body.

22. A distributor plate as claimed in any one of claims 18 to 21 wherein the extension member is attachable to a periphery of the supporting body by a joining member insertable in aligned cavities formed in the supporting body and the extension arm member.

23. A distributor plate as claimed in claim 22 wherein the joining member is a pin.

24. A distributor plate as claimed in claim 10 wherein the locating means comprises a planar member which is seated on and covers the supporting body, the planar member having a projection thereat. '

25. A distributor plate as claimed in claim 24 wherein the projection is a lipped flange arranged at the periphery of the planar member and adapted to be in contact with a periphery of the or each wear element .

26. A distributor plate as claimed in claim 24 wherein a plurality of discrete projections are spaced around and arranged about the periphery of the planar member, each adapted to be in contact with a periphery of the or each wear element .

27. A distributor plate as claimed in any one of claims 24 to 26 wherein the planar member is attachable to the supporting body by one or more joining members insertable in aligned cavities formed in the supporting body and the planar member.

28. A distributor plate as claimed in claim 27 wherein the joining member is a pin.

29. A distributor plate as claimed in any one of claims 5 to 9 or 11 to 28 wherein the projection solely or additionally comprises a pin arranged outwardly of one said surface of the or each wear element for receipt in a correspondingly-shaped cavity located in the body.

30. A distributor plate as claimed in any one of claims 5 to 9 or 11 to 28 wherein the projection comprises one or more pins arranged outwardly of one said surface of the body each for receipt in a respective correspondingly- shaped cavity located in the or each wear element .

31. A distributor plate as claimed in any one of the preceding claims wherein the locating means is an adhesive substance alone.

32. A distributor plate as claimed in any one of the preceding claims wherein the material contacting surface of the wear element is substantially planar.

33. A distributor plate as claimed in any one of the preceding claims where an or said opposing surface of the or each wear element is affixed to an or said opposing surface of the body.

34. A distributor plate as claimed in claim 33 wherein the opposing surfaces are substantially planar.

35. A distributor plate as claimed in any one of the preceding claims wherein the or each wear element is a plate.

36. A distributor plate as claimed in any one of the preceding claims comprising a single wear element in the form of a circular disc.

37. A distributor plate as claimed in any one of the preceding claims wherein the or each wear element is made of a wear resistant material .

38. A distributor plate as claimed in any one of claims 6 to 9, 12 to 14, 16 to 17, 20 to 21 or 25 to 28 wherein the lipped flange (s) are coated at least in part with a wear resistant material.

39. A distributor plate as claimed in claim 39 wherein the wear resistant material is a hard-facing material.

40. A distributor plate as claimed in claim 39 wherein the hard-facing material includes tungsten carbide.

41. A distributor plate as claimed in any one of the preceding claims wherein the or each wear element is spaced from the body by one or more spacers arranged between opposing surfaces of the body and the wear element (s) so that, when the or each wear element is attached to the body by use of an adhesive substance, the spacer.(s) provide for a predetermined depth of the adhesive substance between the body and the wear element (s) .

42. A distributor plate as claimed in claim 41 wherein one such spacer is a projecting ring on the body, concentric with a central axis of the body and inset from the periphery of the body.

43. A distributor plate as claimed in any one of the preceding claims wherein a peripheral edge of the body is bevelled in at least one position, the bevel adapted for the insertion of a levering tool to facilitate movement of the distributor plate.

44. A distributor plate as claimed ^' in claim 43 wherein the entire peripheral edge is bevelled.

45. A distributor plate as claimed in any one of the preceding claims wherein the impelling rotor is mountable via a coupling element to a shaft of the impactor, wherein the distributor plate has a basal spigot with a cavity in the spigot for receiving the coupling element therein in use.

46. An impelling rotor of a rotating shaft impactor including a distributor plate as defined in any one of claims 1 to 45.

47. A rotating shaft impactor including a distributor plate as^' defined in any one of claims 1 to 45.

48. A method of operating a materials breakage apparatus comprising the steps of: introducing materials into a rotating chamber so as to impact the materials on a distributor plate located in the chamber; and - passing the materials from the chamber by radially ejecting these materials through one or more ejection ports in the chamber wall; wherein said materials are passed from the distributor plate to the ejection ports in a manner which minimises abrasive wear of wear members other than the distributor plate that are located in the chamber.

49. A method as claimed in claim 48 that employs the distributor plate, impelling rotor and rotating shaft impactor of any one of claims 1 to 47.

50. A method of forming a supporting body for a distributor plate comprising the steps of: coating a peripheral region of a supporting body at least in part with a wear resistant material; and forming a recess over a central portion of the supporting body, the recess bounded by the peripheral region.

51. A method of forming a distributor plate comprising the method as claimed in claim 50 and the step of positioning one or more wear elements on the body and into the recess.

52. A method as claimed in claim 49 further comprising the step of shaping a billet of material into the supporting body before the coating step.

53. A method as claimed in claim 49 further comprising the step of reshaping the supporting body after the coating step.

54. A method of retrofitting one or more wear elements to a distributor plate for an impelling rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the method comprising the step of locating said one or more wear elements into position on the distributor plate to cover a surface thereof onto which the material would otherwise be received, at least some of the wear element (s) arranged so that in use the material is ejected across the one or more wear members in a manner which minimises abrasive wear of the said wear members.

55. A method as claimed in claim 54 that comprises the step of positioning a wear element which is arranged in use to partially overlap the one or more wear members so as to cover a surface of said wear member (s) which in 'use would otherwise be subjected to abrasive wear.

56. A method as -claimed in claim 54 or claim 55 that also comprises the step of fitting an extension portion to the distributor plate, the portion arranged in use to partially overlap the one or more wear members .

57. A method as claimed in any one of claims 54 to 56 that employs a wear element which is otherwise as claimed in any one of claims 1 to 47.

58. A retrofittable wear element for use in the method of any one of claims 54 to 56. -

59. A distributor plate for an impelling rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the distributor plate comprising: a supporting body; - one or more wear elements positioned on the body to cover a surface of the body onto which the material would otherwise be received; and locating means for locating the wear element (s) on the body; wherein a coating of a wear resistant material is arranged to protect locations where a join exists between any two of the supporting body, the wear element or the locating means so as to minimise abrasive wear' at the said join.

60. A distributor plate as claimed in claim 59 wherein the supporting body, wear element, locating means or wear resistant material are as defined in any one of claims 1 to 47.

61. An impelling rotor of a rotating shaft impactor including a distributor plate as defined in claim 59 or claim 60.

62. A rotating shaft impactor including a distributor plate as defined in claim 59 or claim 60.

63. A method of forming a distributor plate for an impelling rotor of a rotating shaft impactor, where the impelling rotor defines a chamber arranged in use to rotate about an axis and to radially eject material received therein across one or more wear members arranged adjacent to the distributor plate in the chamber and through one or more ejection ports in a side wall of the chamber, the method comprising the steps of: locating one or more wear elements into position on the supporting body to cover a surface thereof onto which the , material would otherwise be received; and applying a coating of a wear resistant material so as to protect at least some locations where a join exists between the supporting body and the or each wear element so as to minimise abrasive wear at the said join(s) .

64. A method as claimed in claim 63 wherein the coating is applied circumferentially about the supporting body.

65. A method as claimed in claim 63 or claim 64 further comprising the step of shaping a billet of material into the supporting body before the coating step.

66. A method as claimed in claim 63. or claim 64 further comprising the step of reshaping the supporting body after the coating step.