GB2393638A

GB2393638A - Aggregate cleaning apparatus

Info

Publication number: GB2393638A
Application number: GB0219594A
Authority: GB
Inventors: Darren Nelson
Original assignee: CARNELL CONTRACTORS Ltd
Current assignee: CARNELL CONTRACTORS Ltd
Priority date: 2002-08-22
Filing date: 2002-08-22
Publication date: 2004-04-07
Anticipated expiration: 2022-08-22
Also published as: EP1391251A2; GB0219594D0; EP1391251A3; GB2393638B

Abstract

Aggregate cleaning apparatus for cleaning areas such as French drains comprises aggregate feed means for dirty aggregate 101, cleaning means 15, aggregate return means for cleaned aggregate (fig 2, 104) and debris distribution means 30. In use, the aggregate feed means presents the dirty aggregate 101 to the mesh cleaning means 15 which agitates the dirty aggregate 101, preferably by rotation to release debris 105 from the dirty aggregate 101. The cleaning means 15 preferably takes the form of a drum rotated about a central axis and the feed means is preferably a hopper 10 with a conveyer to progressively deliver dirty aggregate 101 to the cleaning means 15. Ribs may be present within the drum to further agitate the aggregate. A shredder such as a chopper or a shearing blade may be present to shred the debris 105 into finer grade particles before it is distributed.

Description

( 1 2393638

Aggregate Cleaning The present invention relates to aggregate cleaning and more particularly but not exclusively to drain aggregate cleaning with respect to French drains associated with roads and highways.

It is essential to efficiently and speedily drain away surface water in situations such as those presented on a highway or road. Typically, a camber or incline is provided such that the surface water flows under gravity towards a drain. Typically, a so-called French drain is used with regard to highway drainage. A French drain comprises a trench or ditch filled with relatively large stones or aggregate in order to act as a soakaway for the surface water flowing under gravity towards the drain.

It will be appreciated that over a period of time, the aggregate used in French drains and other soakaway drainage systems becomes clogged and fouled by dirt, organic matter, oil and other materials. Traditionally, in such circumstances, periodically the aggregate, or at least a top proportion of the aggregate, in the trench or ditch must be removed. The contaminate contents is then collected and disposed of at a landfill site. Unfortunately, previous systems have been relatively inefficient and current objectives are to avoid use of landfill. Furthermore, previous aggregate renovation techniques used with regard to French drain arrangements have been relatively bulky and normally required closure of at least one lane of a highway with resultant traffic congestion. Nevertheless, the aggregate regularly becomes contaminated by silt, small particles and organic mater which is compacted over time.

In accordance with the present invention there is provided apparatus for cleaning aggregate, the apparatus comprising aggregate feed means for dirty aggregate, cleaning means, aggregate return means for cleaned aggregate and debris distribution means, the aggregate feed means in use presenting dirty aggregate to the cleaning means comprises a mesh whereby motion within the cleaning means agitates the dirty aggregate to release debris from the dirty

( aggregate with the cleaned aggregate presented to the aggregate return means whilst debris is presented to the debris distribution means.

Preferably, the motion is rotation.

Normally, the cleaning means takes the form of a drum rotated about a central axis. Typically, the mesh is concentric about an axis of rotation.

Alternatively, the mesh performs an epicyclic rotation.

Preferably, the aggregate feed means is a hopper with a conveyer to progressively deliver dirty aggregate to the cleaning means. Typically, the dirty aggregate is arranged to drop from the conveyor upon the cleaning means for abrupt percussive shock engagement therewith to facilitate debris released from the dirty aggregate.

Preferably, the mesh has an interstitial or aperture size determined by the expected minimum aggregate dimension. Typically, the mesh interstitial or aperture size is approximately 1 Omm. Possibly, the mesh can be readily changed within the cleaning means to accommodate different aggregate sizes.

Alternatively, the mesh interstitial or aperture size can be adjusted.

Advantageously, the mesh is formed by a plurality of panels.

Preferably, the apparatus includes agitator means. Typically, the agitator means comprises elongate ribs appropriately spaced about the cleaning means.

Possibly, the elongate ribs extend substantially from one end of the screen to the other. Normally, the ribs will be straight. Alternatively, the ribs will be bent, spiralled or wavy along an internal surface of the cleaning means. Typically, the ribs will be substantially V-shaped to sweep aggregate with them as the mesh rotates until released under gravity in a tumbling action for shock and abrasive debris release.

Preferably, the cleaning means is angled. Typically, the cleaning means is higher at a feed end which receives the dirty aggregate from the feed means.

Advantageously, the angle of the cleaning means is adjustable. Possibly, the

angle of the cleaning means could be adjusted through a hydraulic or pneumatic ram or by adjusting the height of the hydraulic suspension on the attending articulated tractor unit so lifting the fifth wheel.

Preferably, the cleaned aggregate falls from the cleaning means upon a conveyor for the aggregate return means.

Preferably, the debris falls through the mesh upon a conveyor for the debris distribution means. Typically, the debris distribution means includes a shredder to shred the debris to finer grade particles. Possibly, the shredder is a chopper or shearing blade arrangement. Normally, the debris distribution means will include a scatter disc to disperse the debris. Possibly, the distribution means presents the debris to a separator dependent upon type of debris. Possibly, the separator operates dependent upon debris weight.

Alternatively, the separator comprises a manually operated diverter. Possibly, the distribution means presents the debris to a collector. Advantageously, brush means sweeps the mesh to facilitate removal of debris from the mesh.

Typically, the distribution means includes a guard to limit scatter of debris.

Also in accordance with the present invention there is provided an arrangement comprising apparatus as described above and dirt aggregate extraction means arranged to extract dirty aggregate from a trench or ditch and present that dirty aggregate to the aggregate feed means.

Preferably, the extraction means includes a helical screw arranged to lift dirty aggregate towards the feed means or vacuum suction or backhoe bucket.

Preferably, the extractor means includes compressed air jets to facilitate the release of dirty aggregate conglomeration and so extraction. Normally, the airjets are located upon the screw edges.

Preferably, the extractor means includes an extendible arm to facilitate access to dirty aggregate. This may be incorporated on the trailer or on a separate vehicle such as a small excavator.

1 ( Normally, the apparatus as described previously and/or the dirty aggregate extraction means are provided upon a self-propelling vehicle chassis or a vehicle trailer readily towed for operational use.

Also in accordance with the present invention there is provided a method of cleaning dirty aggregate including the steps of; a. Extracting dirty aggregate; b. Agitating that dirty aggregate in a mesh; c. Removing debris from the mesh; and, d. Scattering that debris.

Preferably, the method includes the step of selectively angling the orientation of the mesh to facilitate agitation for release of debris and/or speed of operation.

Preferably, the method includes the step of analysing the debris to determine acceptability for shredding and/or scattering. Advantageously, the method includes separating the debris dependent upon type whereby a proportion of the debris is scattered whilst the remainder is directed towards a collector for appropriate disposal.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which; Fig. 1 is a schematic cross-section of an apparatus for cleaning aggregate in accordance with the present invention; Fig. 2 is a schematic plan crosssection of the apparatus depicted in Fig. 1; Fig. 3 is a schematic crosssection along the line A-A in Fig. 2; Fig. 4 is a schematic cross-section along the line B-B in Fig. 2; and,

Fig. 5 is a schematic detailed depiction of a debris scatter arrangement in accordance with the present invention and initially shown in Fig. 1.

As described above, the present invention particularly relates to an apparatus for cleaning aggregate and in particular aggregate taken from so-

called French drains. The apparatus is also part of an arrangement for extraction of aggregate and return of that aggregate to a French drain trench or ditch. The present invention also incorporates a method of aggregate cleaning.

Fig. 1 illustrates, in a schematic cross-section, a cleaning apparatus 100 located upon a trailer 2 which is normally towed by a truck or tractor unit 1. In such circumstances, the apparatus 100 can be readily transported to a site for operation. Normally, the cleaning apparatus 100 will be driven by a hydraulic power unit 3 is a self contained engine/hydraulic power pack not dependent on the engine of truck 1. In an operational situation the present cleaning apparatus will be combined with an excavator for dirty aggregate from the French drain and normally a trailing compactor machine to level and flatten the returned cleaned aggregate to the drain.

As indicated previously, a French drain consists of a trench adjacent to a highway or roadside edge which is filled with coarse aggregate material of irregular shape and normally 30 to 40mm in diameter. Over a period of time the upper portions of the drain becomes blocked with silt, organic matter and highway debris. This blockage inhibits or even prevents drainage of surface water from the highway and thereabouts draining away to lower levels of the trench. Typically, only the top third or half of the drain aggregate becomes dirty and contaminated.

In accordance with the cleaning apparatus 100 dirty aggregate 101 is loaded Into an aggregate feed hopper 10 such that a dirty aggregate feed conveyor 11 progressively feeds the dirty aggregate to a cleaning combination.

The dirty or contaminated aggregate 101 may be scooped into the hopper 10 using a conventional backhoe or bucket excavation system or using a specific excavator as described later.

( The cleaning combination is arranged such that at end 102 of the conveyor 11 drops dirty aggregate into shock percussive engagement with the cleaning combination to facilitate detachment of debris and break up of the possibly still partly conglomerated aggregate stones. Normally, the cleaning combination is a drum mounted for rotation about a spindle and bearing 16 and guide rollers 17. The cleaning combination comprises a mesh 15. Where necessary this mesh 15 may be reinforced with a perforated screen. The mesh apertures or interstitial size are determined by the degree of cleaning and expected aggregate size. A mesh aperture or interstitial size of approximately lOmm will ensure aggregate with a normal dimension of 30 to 40mm will not pass through the cleaning combination whilst debris particles of less than 10mm will fall through the mesh. The cleaning is due to percussive action in tumbling and abrasion by sliding and rubbing against the mesh 15 and other aggregate particles during rotation.

The mesh 15 comprises a number of inter-linked panels such that the panels can be readily removed for cleaning, maintenance and repair. It will also be understood that providing panels allows the mesh 15 to be specifically chosen or altered dependent upon expected aggregate dimensions and debris dimensions. The mesh 15 is rotated about the bearing typically at the rear of the combination. Guide rollers 17 facihtate stable rotation of the drum and mesh 15 about the axis of the drum. A chain 19 through a sprocket drive and gear motor system 18 provides rotation of the cleaning combination about the drum axis. The speed of rotation can be varied dependent upon the degree of cleaning required. It will be understood that cleaning of the dirty aggregate is principally provided by agitation and abrasion between the aggregate stones themselves and surfaces of the cleaning combination.

The cleaning combination is normally angled as depicted in Fig. 1 such that the dirty aggregate falls from the feed end 102 to an exit end 103 under gravity. The angle of the cleaning combination and speed of rotation will determine the residence time of dirty aggregate within the cleaning

( / combination and therefore the speed of cleaning.

The inner surface of the mesh 15 will include agitators. These agitators may be part of the mesh 15 structure or separate elements located between mesh panels. These agitators take the form of ribs which extend radially and/or longitudinally at appropriate locations along the length of the cleaning combination. The agitators are provided in order to further facilitate debris release from the dirty or contaminated aggregate.

Normally, the cleaning apparatus is contained within a cover 4 in order to provide environmental protection from rain, etc. and airborne debris whilst preventing release of such debris about the apparatus as a result of the aggregate cleaning operation.

The cleaning combination is mounted upon a frame 13 which in turn is secured to a chassis 12 of the trailer 2. As indicated previously, normally a truck 1 is used to bring the cleaning apparatus to site. Alternatively, it will be appreciated that the present cleaning apparatus could be incorporated in a self-

propelled vehicle. In this event, the means of inclining the apparatus using the tractor unit hydraulic suspension may be replaced with independent height adjustment or by inchoation of the drum by mounting the drum frame on a rear pivot and lifting the front end by means of a hydraulic ram. The angle of tilt for the cleaning combination can be adjusted as indicated previously for speed of cleaning operation and or effectiveness of such operation. It will be appreciated that the greater the angle the greater will be the promotion of a tumbling action in the aggregate from the feed end 102 to the exit end 103 under gravitational force. Ideally, a cleaning arrangement in accordance with the present invention comprising the present cleaning apparatus 100 with a dirty aggregate excavator machine and a cleaned aggregate return mechanism which will each move together along a drain in a continuous process. In such circumstances, the angle of the cleaning combination determined through the height of the tractor unit suspension height along with the speed of rotation will principally

determine the rate of throughput of aggregate and so the speed with which the cleaning arrangement can move.

Cleaned aggregate 104 falls from the exit end 103 into a cleaned aggregate hopper 41. A cleaned aggregate conveyor 42 then directs the cleaned aggregate towards a exit chute 44 for return to a drain trench. As indicated previously, normally the cleaned aggregate will then be levelled and flattened by appropriate machinery. The rate of return of cleaned aggregate is controlled by the chute 44 release aperture along with the angular attitude of the exit chute 44. This angular attitude is determined by an exit conveyor hydraulic ram 43 as required. Released contaminant debris falls through apertures in the mesh 15 of the cleaning combination and onto a debris conveyor 30. The contaminant debris is then conveyed by further conveyors 31, 34 to a dispersion arrangement. Typically, a debris hopper 33 is provided from which the debris is progressively presented to the dispersion arrangement to be appropriately dealt with. The angles of the conveyor 34 are set by hydraulic rams 35 such that the dispersion arrangement is at a relatively elevated position for spraying the debris about an embankment or other area adjacent to the cleaning apparatus.

The cleaning combination is generally located within an outer skin 20 so that debris can not escape. Furthermore, brush elements will be provided in order to sweep the mesh 15 and so release the debris to the conveyor 30 for dispersal as described.

The dispersion arrangement comprises a dispersion disc 36 which Is horizontal with a multiplicity of blades in order to scatter those particles 105 within a desired arc towards the embankment or other area. A motor 37 is provided in order to rotate the disc with sufficient force to provide scattering of debris particles 105. Typically, a guard screen 38 is provided in order to prevent debris particles being directed back towards the cleaning apparatus 100 or workers.

( An up-lift conveyor 31 or the hopper conveyor 34 or any other means may be provided in order to deliver the debris to a separator (not shown) or holding tank. The debris may be selected dependent upon its toxicity, weight or other characteristic. In such circumstances, only inert or environmentally acceptable debris will be scattered by the dispersion arrangement.

During transit the cleaning apparatus will be arranged whereby the cleaning combination will be at its lowest angular position and the conveyors 34 and 42 retracted by the hydraulic rams 35 and 43 respectively.

Fig. 2 is a plan cross-section of a cleaning apparatus 100 in accordance with the present invention. Thus, dirty or contaminated aggregate 101 is loaded into hopper 10 and taken by conveyor 11 to the cleaning combination including mesh 15. The cleaned aggregate 104 is returned through chute 42 whilst the debris 105 is scattered by a dispersion disc 36. The aggregate and therefore the French drain from which the aggregate 101 is removed can be either side of the cleaning apparatus 101. Thus, the conveyors 34 and 42 can be respectively rotated as shown by arrowheads A and B. In such circumstances, the cleaned aggregate 104 can be returned to a drain trench or ditch either side of the cleaning apparatus 100. Similarly, debris 105 can be scattered either side and an extractor machme will operate in the area between the conveyors 34 and 42 on the drain ditch side of the apparatus 100.

The dirty aggregate extractor can be a separate backhoe mechanical digger but alternatively could be an integral part of a cleaning arrangement incorporating the apparatus 100 in accordance with the present invention.

Where an integral part of the arrangement, an extending arm, which will normally be hydraulically operated, will project from the hopper 10 towards a French drain such that dirty aggregate is removed. It will be understood that there may be a crash barrier or other obstacle between the trailer 2 and the French drain such that the provision of an extending arm with other manipulation will allow access to the dirty aggregate of the French drain.

Typically, the arm will include two rotating helical screws. These helical screws will break into the dirty aggregate to loosen the aggregate stones. In turning

the hehcal screws, the stones are propelled or lifted towards a bucket conveyor of the extraction arrangement. The bucket conveyor will then deliver the dirty aggregate to the hopper 10 for processing as described previously. In order to enhance performance of the helical screws in propelling and drawing the contaminated and dirty aggregate to the bucket conveyor and then the hopper 10, it is possible to provide a compressed air supply fed through jets at the leading tips of the hehcal screws in order to loosen conglomeration of the dirty aggregate stones.

It will be understood that the two rotating hehcal screws act in a similar fashion to an Archimedes screw lift arrangement.

As Educated above, the cleaned aggregate falls from the rear of the cleaning combination comprising mesh 15. The cleaned aggregate in the aggregate hopper 41 is then fed by the conveyor 42 towards a chute 44 for delivery into the excavated trench or ditch. As the chute 44 is after the extraction position, i.e. intermediate chute 42 and debris dispersion, the cleaned aggregate can be returned directly into the trench. Subsequently, the cleaned aggregate will be levelled and compacted as required.

The cleaned aggregate conveyor 42 may swivel through an angular range of 180 about a kingpin pivot 40 at the rear of the trailer 2. Thus, the cleaned aggregate Is appropriately released back into the top levels of the French drain trench. Typically, the exit chute 44 may also be swivelled through an angle of up to 90 for spreading of the cleaned aggregate across the width of the French drain trench.

The contaminant debris is presented to the dispersion arrangement including the dispersion disc 36 through a conveyor 34. Generally, as described previously, a debris hopper 33 is provided and the conveyor 34 may swivel about a turn table base 32 (Fig. 1) beneath a hopper 33 in angular range of 270 in order that there can be appropriate dispersal and scatter of the debris upon an embankment or other acceptable areas adjacent the highway and French drain. As indicated previously, a guard 38 Is generally provided in order to

( protect the cleaning apparatus and any workers. This guard 38 may automatically adjust dependent upon the angular position of the base 32 in order to provide the necessary protection to the apparatus, trailer 2, truck 1 and any workers. It will also be understood that the rams 35 allow alteration of the elevation point for scatter by the disc 36 and this will allow alteration of the range and distribution of debris scatter.

Fig. 3 illustrates a schematic cross-section along line A-A depicted in Fig. 2. Thus, contaminated and dirty aggregate 101 is located in hopper 10 such that the dirty aggregate conveyor 11 can progressively deliver that contaminated aggregate to the cleaning combination including mesh 15. The cleaning apparatus containment skin 20 retains any released contaminant debris for delivery through an aperture 106 to the debris conveyor 30. As can be seen, the cleaning combination including mesh 15 rotates in the direction of arrowhead C, thus in order to facilitate removal of debris a brush 107 may be provided. Typically, a number of brush elements 107 will be provided about the mesh 15. Normally, these brush elements 107 will be located on the up-side of the cleaning combination drum rotation direction.

Fig. 4 is a schematic cross-section in the direction B-B depicted in Fig. 2.

Rotation of the cleaning combination comprising mesh 15 is provided in the direction of arrowhead C with rollers 17 providing location of the cleaning combination. As Indicated previously, a motor 18 through a chain 19 drives rotation with a tension pulley 22 ensuring efficient power transfer through the chain 19.

Within the screen 108 there are provided agitators 21. These agitators 21 as depicted principally extend along the length of the cleaning combination comprising mesh 15. In such circumstances, contaminated and dirty aggregate dropped by the feed conveyor 11 upon the mesh 15 is tumbled. The effect of the agitators 21 is to sweep aggregate stones with them during the rotation process upwards until due to gravity those dirty aggregate stones are dropped in a tumbling action as shown by aggregate 101 a downwards withm the cleaning combination. By such process, there is shock and abrasion release of

l debris from the contaminated dirty aggregate. As indicated previously, the released debris falls through the mesh 15 upon conveyor 30 for subsequent dispersal. The cleaning combination of mesh 15 as indicated previously is generally a rotating drum at an inclined angle upwards from the rear of trailer 2. In such circumstances, aggregate 101 will be swept and tumbled by the agitators 21 several times before exiting the cleaning combination at the exit end 103 (Figs. 1 and 2). The number of such tumbling actions will depend upon the rate of rotation of the cleaning combination and the angle of the combination. Clearly, higher rates of rotation will bring greater numbers of tumbling actions per unit time whilst a greater angle of inclination for the cleaning combination will generally speed the throughput under gravitational force of the aggregate 101 through the cleaning apparatus 100.

As an alternative to straight agitators 21 it is possible that that agitators which have a spiral or curved or wavy path from the input end 102 (Fig. 1 and 2) to the exit end 103 could be provided. The lateral proportion of such agitator configurations resisting the angular presentation of the combination in order to slow aggregate throughput under gravity. It may also be possible to provide radial segment agitator portions which again slow aggregate throughput and therefore subject that aggregate to greater agitation and abrasion release of debris as required. In short, it is a operational choice dependent upon the speed with which the aggregate must be cleaned which determines the rate of rotation and angular presentation of the cleaning combination along with the agitator 21 configuration used. The speed with which aggregate must be cleaned is dependent upon the level of contamination, the speed of extraction of dirty aggregate and speed of return of cleaned aggregate to the French drain trench which In turn determines the rate with which a cleaning arrangement in accordance with the present invention can be driven relative to a French drain.

As can be seen in Fig. 4, the agitators 21 are generally V-shaped and of a sohd construction in order to resist the damaging effects of repeated aggregate collisions. However, where possible a displacement mechanism may be

provided for each agitator 21 such that the height of that agitator inwardly of the perforated screen can be varied if required. Similarly, the number and distribution of agitators may be varied through removal or retraction into the cleaning combination.

Fig. 5 Illustrates in schematic cross-section and greater detail a dispersion arrangement 200 in accordance with the present invention. Thus, debris released from contaminated and dirty aggregate is lifted by conveyor 34 in the direction of arrowhead D towards a dispersion disc 36. The dispersion disc 36 includes a plurality of radial blades 3/ such that as the disc 36 is rotated the debris dropped in the direction of arrowheads D is scattered for easier dispersal by rotation of the disc 36. Rotation of the disc 36 is provided by a motor 39. The scattered debris 105 is distributed by the rotation of the disc 36 but as indicated previously, the elevation and angular position of the dispersion arrangement 200 relative to the cleaning apparatus is determined by a rotation about a turn table base mounting 32.

It will be appreciated that the range of scatter will be dependent upon the rotational speed of the disc 36 along with the depth of blades 109.

Provision of the dispersion arrangement 200 in accordance with the present invention allows acceptable scatter of the debris rather than separation of the debris into a collector for subsequent disposal in a landfill site. However, there may be contaminants in the dirty aggregate which require removal. In such circumstances, an operator may analyse the released debris from the dirty aggregate 101 and then dependent upon that analysis divert the debris from the dispersion arrangement 200 into a separate collector or holding tank for subsequent disposal. Normally, the debris 105 scattered by the dispersion arrangement 200 will be sufficiently finely graded that it will not be readily noticeable upon an embankment adjacent a highway.

The method of the present invention involves, as indicated above, using a cleaning arrangement effectively comprising three principal functional components. Firstly, an extraction mechanism or machine Is provided for

( removal of contaminated and dirty aggregate 101 from a French drain. The extraction machine or components release and feed the dirty aggregate 101 to a hopper 10 as described previously with regard to the cleaning apparatus 100 such that the dirty aggregate 101 Is subject to agitation and abrasion release of debris from the dirty aggregate 101. Thus, the cleaned aggregate 104 and the debris 105 are separated across the cleaning combination and in particular mesh 15. In accordance with the method, the cleaned aggregate 104 is returned to the excavated trench whilst the debris 105 is scattered for environmentally acceptable distribution about an embankment or other area adjacent the highway. The cleaned aggregate 104 Is then levelled by a compactor machine.

Generally, the mesh 15 in accordance with the present invention will have a uniform mesh size or Interstitial dimension throughout the length of the cleaning combination. However, it will be appreciated that a mesh could be provided having a graded size distribution from the feed end 102 to the exit end 103 of the cleaning combination. Alternatively, the mesh couldhave a random mesh diameter if required. In any event, as indicated previously the mesh 15 will generally comprise a number of panels secured about the internal periphery of the drum to allow maintenance, cleaning and change in mesh aperture/interstitial dimension necessary for different sizes of presented aggregate. Typically, the cleaning combination including mesh 15 will have a length necessary to provide adequate cleaning of dirty aggregate 101. Typically, the cleaning combination will have a length in excess of 3 metros.

As indicated above, a French drain will typically only become blocked to a certain depth such that only that depth of contaminated and dirty aggregate will be removed. Generally, a French drain will have a width in the range 600 to 1200mm and a contamination depth can be up to 800mm. In such circumstances, the chute 44 in accordance with the present invention will generally be provided with an oscillation feature to spread the cleaned aggregate back across the full width of the trench such that a subsequent levelling and compaction machine only has limited requirements for spreading

( the cleaned aggregate fill into the trench. Similarly, the extraction machine, whether it be an independent backhoe digger or integral component of the present arrangement, will generally require an extension arm or other device to allow dirty aggregate to be removed from the full width of the drain and to the appropriate depth.

By interchanging and/or combination of different types and mesh sizes in the mesh 15 any type of debris can be removed and aggregate effectively cleaned/screened by the present apparatus and arrangement. The present invention works equally well for single and multiple size aggregate stone with heavy or light levels of contamination and in wet or dry weather. Where possible the mesh aperture dimension may be adjusted in situ by adjustment means or different mesh panels assembled into the cleaning apparatus. A number of cleaning combinations may be cascaded in terms of aggregate size so that firstly coarse aggregate is cleaned then finer grades in subsequent cleaning combinations with all cleaned aggregate consolidated in a cleaned aggregation hopper. In such a cascade, the finer grade aggregations would fall through with the debris released from the coarser aggregate which, when cleaned, may pass directly to the hopper.

The mesh as indicated previously, may be cleaned by brush elements 107 or through appropriate compressed air-jetting.

The rotation speed as well as angular presentation of the cleaning combination substantially determines the effectiveness of aggregate cleaning.

Thus, m accordance with the present invention, it is possible to provide a controller which automatically regulates the speed of the apparatus to achieve the most effective cleaning performance.

Although the cleaning combination is generally cylindrical it will be understood that a cleaning combination comprising mesh could have a conical or barrelled shape to facilitate aggregate cleaning as required. Such comcal, barrelled or curved waisted configurations may augment the effectiveness of the agitators for agitation and abrasion release of debris from the aggregate.

Whilst endeavouring in the foregoing specification to draw attention to

those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection m respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

( Claims:

1. An apparatus for cleaning aggregate, the apparatus comprising aggregate feed means for dirty aggregate, cleaning means, aggregate return means for cleaned aggregate and debris distribution means, the aggregate feed means in use presenting dirty aggregate to the cleaning means comprises a mesh whereby motion within the cleaning means agitates the dirty aggregate to release debris from the dirty aggregate with the cleaned aggregate presented to the aggregate return means whilst debris is presented to the debris distribution means.

2. An apparatus as claimed in claim 1 wherein the motion is rotation.

3. An apparatus as claimed in claim 1 or claim 2 wherein the cleaning means takes the form of a drum rotated about a central axis.

4. An apparatus as claimed in any of claims 1 to 3 wherein the mesh is concentric about an axis of rotation.

5. An apparatus as claimed in any of claims 1 to 3 wherein the mesh performs an epicyclic rotation.

6. An apparatus as claimed in any preceding claim wherein the aggregate feed means is a hopper with a conveyer to progressively deliver dirty aggregate to the cleaning means.

7. An apparatus as claimed in any preceding claim wherein the dirty aggregate is arranged to drop from the conveyer upon the cleaning means for abrupt percussive shock engagement therewith to facilitate debris released from the dirty aggregate.

1&p, (

8. An apparatus as claimed in any preceding claim wherein the mesh has an interstitial or aperture size determined by the expected minimum aggregate dimension.

9. An apparatus as claimed in any of claims 1 to 9 wherein the mesh can be readily changed within the cleaning means to accommodate different aggregate sizes.

10. An apparatus as claimed in any preceding claims wherein the mesh interstitial or aperture size can be adjusted.

11. An apparatus as claimed in any preceding claim wherein the mesh is formed by a plurality of panels.

12. An apparatus as claimed in any preceding claim wherein the apparatus includes agitator means.

13. An apparatus as claimed in claim 13 wherein the agitator means comprises elongate ribs appropriately spaced about the cleaning means.

14. An apparatus as claimed in claim 13 wherein the elongate ribs extend substantially from one end of the screen to the other.

15. An apparatus as claimed in claim 13 or claim 14 wherein the ribs will be straight.

16. An apparatus as claimed in claim 13 or claim 14 wherein the ribs will be bent, spiralled or wavy along an internal surface of the cleaning means.

17. An apparatus as claimed in any of claims 13 to 16 wherein the ribs will be I substantially V-shaped to sweep aggregate with them as the mesh rotates until released under gravity in a tumbling action for shock and abrasive debris release.

18. An apparatus as claimed in any preceding claim wherein the cleaning means is angled.

19. An apparatus as claimed in any preceding claim wherein the cleaning means is higher at a feed end which receives the dirty aggregate from the feed means.

20. An apparatus as claimed in claim 18 wherein the angle of the cleaning means is adjustable.

21. An apparatus as claimed in claim 20 wherein the angle of the cleaning means could be adjusted through a hydraulic or pneumatic ram or by adjusting the height of the hydraulic suspension on the attending articulated tractor unit so lifting the fifth wheel.

22. An apparatus as claimed in any preceding claim wherein the cleaned aggregate falls from the cleaning means upon a conveyor for the aggregate return means.

23. An apparatus as claimed in any preceding claim wherein the debris falls through the mesh upon a conveyor for the debris distribution means.

24. An apparatus as claimed in any preceding claim wherein the debris distribution means includes a shredder to shred the debris to finer grade particles.

25. An apparatus as claimed in claim 24 wherein the shredder is a chopper or shearing blade arrangement.

(

26. An apparatus as claimed in claim 24 or claim 25 wherein the debris distribution means includes a scatter disc to disperse the debris.

27. An apparatus as claimed in any of claims 24 to 26 wherein the distribution means presents the debris to a separator dependent upon type of debris.

28. An apparatus as claimed in claim 27 wherein the separator operates dependent upon debris weight.

29. An apparatus as claimed in claim 27 wherein the separator comprises a manually operated diverter.

30. An apparatus as claimed in any preceding claim wherein brush means sweeps the mesh to facilitate removal of debris from the mesh.

31. An apparatus as claimed in claim 24 and any claim dependent thereon wherein the distribution means includes a guard to limit scatter of debris.

32. An apparatus as claimed in any preceding claim wherein a star conveyor is provided between the aggregate feed means and the cleaning means in order to provide initial debris release from the dirty aggregate.

33. An apparatus as claimed in claim 32 wherein the star conveyor comprises a plurality of star axle wheels with inter-engaging flexible fingers which promote transport of the aggregate towards the cleaning means whilst achieving desirable percussive shock engagement to dislodge debris from the dirty aggregate whereby that debris falls through the star conveyor.

34. An apparatus for cleaning aggregate substantially as herein before described with reference to the accompanying drawings.

l (

35. An arrangement comprising an apparatus as claimed in any of classes 1 to 34 and dirty aggregate extraction means arranged to extract dirty aggregate from a trench or ditch and present that dirty aggregate to the aggregate feed means.

36. An arrangement as claimed in claim 35 wherein the extraction means includes a helical screw arranged to lift dirty aggregate towards the feed means or vacuum suction or backhoe bucket.

37. An apparatus as claimed in claim 35 or claim 36 wherein the extraction means includes compressed air jets to facilitate the release of dirty aggregate conglomeration and so extraction.

38. An apparatus as claimed in claim 37 wherein the air jets are located upon the screw edges.

39. An apparatus as claimed in any of claims 35 to 39 wherein the extraction means includes an extendible arm to facilitate access to dirty aggregate.

40. An apparatus as claimed in any of claims 35 to 40 wherein the extraction means is incorporated on the trailer or on a separate vehicle such as a small excavator.

41. An apparatus as claimed in any of claims 35 to 40 wherein the apparatus as described previously and/or the dirty aggregate extraction means are provided upon a self-propelling vehicle chassis or a vehicle trailer readily towed for operational use.

42. An arrangement for cleaning aggregate substantially as herein before described with reference to the accompanying drawings.

43. A method of cleaning dirty aggregate including the steps of; a. Extracting dirty aggregate;

l b. Agitating that dirty aggregate in a mesh; c. Removing debris from the mesh; and, d. Scattering that debris

44. A method as claimed in claim 43 wherein the method includes the step of selectively angling the orientation of the mesh to facilitate agitation for release of debris and/or speed of operation.

45. A method as claimed in claim 43 or claim 44 wherein the method includes the step of analysing the debris to determine acceptability for shredding and/or scattering.

46. A method as claimed in any of claims 43 to 45 wherein the method includes separating the debris dependent upon type whereby a proportion of the debris is scattered whilst the remainder is directed towards a collector for appropriate disposal.

47. A method of cleaning dirty aggregate substantially as herein before described with reference to the accompanying drawings.

48. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.