[1] The present invention relates to an apparatus and method for processing a crop residue, including but not limited to processing crop residue for destroying weed seeds in the crop residue.

Background

[2] Infestation of weeds in crop fields reduces the productivity of farms. Traditional harvesting equipment threshes harvested material and separates the grain for storage while expelling and spreading the crop residue including straw, chaff and weed seeds. This allows unwanted weed seeds to germinate in subsequent cropping seasons in the crop fields.

[3] A typical means of controlling annual weed population is the use of herbicides. However, the prolonged exposure of herbicides has resulted in weeds developing resistance to these chemicals.

[4] Current techniques for controlling weed populations have concentrated upon the harvest weed seed control paradigm. This involves targeting weed seeds during crop harvest by collecting and managing weed seed bearing crop residue. The collection and management is conducted using a form of harvest weed seed control system, such as a chaff cart or a towed baler. This post-harvest crop residue is further processed in order to destroy the weed seeds, via the burning of chaff heaps, or disposing of the weed seed, via distributing the bales as feed for livestock.

[5] A recent development in harvest weed seed control systems is the inclusion of a cage mill to further process the crop residue as demonstrated in Australian Patent No. 2009214835. This destroys weed seeds found within the crop residue. However, the use of a cage mill for destroying the weed seeds is an energy inefficient process. Additionally, the cage mill is a complicated instrument which is costly to manufacture and maintain.

[6] The present invention seeks to overcome, or at least substantially ameliorate, the disadvantages and/or shortcomings of the background art or to provide an alternative.

[7] In this specification the terms "comprising" or "comprises" are used inclusively and not exclusively or exhaustively. [8] Any references to documents that are made in this specification are not intended to be an admission that the information contained in those documents form part of the common general knowledge known to a person skilled in the field of the invention, unless explicitly stated as such.

Summary of the Invention

[9] According to an aspect of the invention, there is provided an apparatus for processing a crop residue, comprising:

a housing having an inlet for receiving the crop residue and an outlet for discharging the crop residue;

one or more rotors located in the housing, each rotor comprising a plurality of radially extending impact members;

wherein the plurality of radially extending impact members are configured to rotate with the one or more rotors and impact against the crop residue, so that lighter material of the crop residue is subjected to less impacts and denser material of the crop residue is subjected to relatively more impacts.

[10] In an embodiment of the invention, the housing is elongate.

[11] In an embodiment of the invention, at least one rotor further comprises at least one radially extending pitched member arranged to urge the crop residue to move through the elongate housing.

[12] In an embodiment of the invention, at least two radially extending pitched members are located at different points along each shaft of the one or more rotors.

[13] In an embodiment of the invention, the apparatus for processing a crop residue further comprises one or more blowers arranged to urge the crop residue to move through the elongate housing.

[14] In an embodiment of the invention, at least one blower is located at an inlet end of the elongate housing.

[15] In an embodiment of the invention, the housing is inclined relative to the horizontal. [16] In an embodiment of the invention, the housing is shaped so that it approximates the outer dimensions of the one or more rotors.

[17] In an embodiment of the invention, the housing is shaped so that it substantially follows the orbit of a tip of the impact members.

[18] In an embodiment of the invention, the apparatus for processing a crop residue comprises two rotors located in the housing.

[19] In an embodiment of the invention, the two rotors are aligned parallel to each other.

[20] In an embodiment of the invention, there is a gap separating each of the two rotors from each other between the tips of the impact members.

[21] In an embodiment of the invention, the two rotors are aligned parallel to each other, so that the plurality of radially extending impact members overlap one another in an area of interaction.

[22] In an embodiment of the invention, the plurality of radially extending impact members overlap is in a radial direction with a gap in an axial direction.

[23] In an embodiment of the invention, the plurality of radially extending impact members overlap is in an axial direction with a difference in timing of the impact members being located in an overlapping position.

[24] In an embodiment of the invention, the housing is shaped so that an interior wall of the housing guides the crop residue into the orbital path of the plurality of radially extending impact members.

[25] In an embodiment of the invention, each of the rotors rotate in the same direction so that the plurality of radially extending impact members of each rotor travel in orbitally opposing directions when the tips are close to each other.

[26] In an embodiment of the invention, the plurality of impact members rotate with velocity so as to damage weed seeds upon impact. [27] In an embodiment of the invention, the apparatus for processing a crop residue is mounted to a wheeled chassis.

[28] In an embodiment of the invention, the apparatus for processing a crop residue is mounted to a mechanical harvester.

[29] In an embodiment of the invention, the one or more rotors comprise only two rotors.

[30] In an embodiment of the invention, each impact member comprises a blunt bar.

[31] In an embodiment of the invention, the housing is shaped in the form of two parallel longitudinally intersecting partial cylinders which are connected at a pair of internal walls.

[32] In an embodiment of the invention, the apparatus for processing a crop residue is configured so that the heavier/denser material is seeds which are impacted so as to damage a substantial amount of seed in the crop residue before it exits the outlet and the lighter/less dense material is the remainder of the crop residue which has received fewer or no impacts than the seeds when it exits the outlet.

[33] In an embodiment of the invention, the inlet comprises a bin for receiving crop residue.

[34] In an embodiment of the invention, the bin comprises an auger for moving crop residue from the bin inside of the housing.

[35] In an embodiment of the invention, the housing comprises a restricted opening. In an embodiment, the restricted opening is defined by a hole in an end wall of the housing.

[36] In an embodiment of the invention, each rotor comprises a centrifugal fan for blowing crop residue through the housing at the inlet end of the housing.

[37] In an embodiment of the invention, the outlet comprises a restricted opening in an end wall of the housing. The restricted opening is preferably in the form of an annulus. [38] In an embodiment of the invention, the apparatus comprises a spreader.

[39] In an embodiment of the invention, the spreader comprises a paddle to move crop residue from the outlet out of the spreader.

[40] In an embodiment of the invention, the one or more augers rotate in the same direction as the one or more rotors.

[41] In an embodiment of the invention, the one or more augers rotate at the same speed as the one or more rotors.

[42] According to a second aspect of the invention, there is provided an apparatus for processing a crop residue, comprising:

an elongate housing configured to pass the crop residue through the housing from an inlet to an outlet; and

one or more rotors located in the housing;

wherein the one or more rotors is configured with impact means for interacting with the crop residue, so that a lighter crop residue is subjected to less interactions and a denser seed crop residue is subjected to more interactions.

[43] In an embodiment of the invention, the housing is elongate.

[44] In an embodiment of the invention, the apparatus for processing a crop residue further comprises blowing means to urge the crop residue to move through the housing.

[45] In an embodiment of the invention, the apparatus for processing a crop residue further comprises inclining means to tend to retain denser material of the crop residue in the housing.

[46] In an embodiment of the invention, the housing is arranged to direct crop residue into the impact means.

[47] In an embodiment of the invention, impacts of the impact means tend to transform the denser seed crop residue into the lighter crop residue. In an embodiment the lighter crop residue is more prone to be blown through the housing than the denser seed crop residue. In an embodiment a third form of material is smaller than the lighter crop residue and is subjected to relatively less interactions. [48] In an embodiment of the invention, the impact means are configured to damage weed seeds.

[49] In an embodiment of the invention, the apparatus is configured so that the denser seed crop residue is impacted so as to damage a substantial amount of seed in the seed crop residue before it exits the outlet and the lighter crop residue has received fewer impacts than the seeds crop residue or no impacts when it exits the outlet.

[50] According to a third aspect of the invention, there is provided a method for processing a crop residue, comprising:

receiving the crop residue in an inlet of a housing in the form of two intersecting partial cylinders;

subjecting the crop residue to impacts with a plurality of rotating radially extending impact members, wherein lighter material of the crop residue is subjected to less impacts and denser material of the crop residue is subjected to more impacts; and

discharging the crop residue from an outlet of the housing.

[51] In an embodiment of the invention, the method for processing a crop residue further comprises blowing the crop residue through the housing.

[52] In an embodiment of the invention, the method for processing a crop residue further comprises inclining the housing so as to tend to retain denser material of the crop residue in the housing.

[53] In an embodiment of the invention, the method for processing a crop residue further comprises directing the crop residue into the orbital path of the impact members.

[54] In an embodiment of the invention, the method for processing a crop residue further comprises the impact members causing damage to weed seeds.

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

Description of Drawings [56] In order to provide a better understanding of the present invention embodiments will now be described, by way of example only, with reference to the drawings, in which:-

[57] Figure 1 is a perspective view of the main body of the apparatus; [58] Figure 2 is a perspective view of another main body of the apparatus;

[59] Figure 3 is a perspective view of the main body of the apparatus according to Figure 1 having a means of producing additional airflow;

[60] Figure 4 is a perspective view of the apparatus mounted to a wheeled chassis;

[61] Figure 5 is a perspective view of the apparatus mounted to a portion of a mechanical harvester;

[62] Figure 6 is a perspective view of the apparatus according to Figure 5 having a means of distributing the processed crop residue;

[63] Figure 7 is a perspective view of the inlet of the apparatus;

[64] Figure 8 is an enlarged perspective view of the inlet of the apparatus;

[65] Figure 9 is a top view of the inlet of the apparatus;

[66] Figure 10 is a side view of the inlet of the apparatus and the elongate housing; and

[67] Figure 1 1 is a cross-sectional side view of the inlet of the apparatus and the elongate housing showing the impact members.

Detailed Description

[68] A mechanical harvester produces a continuous stream of crop residue which must be processed quickly, and if possible, efficiently in one pass to render weed seeds nonviable and still allow valuable nutrients/organic matter in waste material to be spread back over a growing area. This avoids a second operation, post-harvest, to process the crop residue. [69] Crop residue from a mechanical harvester is predominantly chaff from harvested crops. Weed seeds are also found alongside the chaff, and as such, is a portion of the crop residue. There is a noticeable difference between the characteristics of chaff and those of weed seeds. The chaff, being the leftover protective casing of the threshed crop, has a low mass relative to greater surface area and is more susceptible to being influenced by air flow. The weed seeds have a higher mass relative to less surface area than the chaff and are less influenced by airflow. It is this difference in the physical properties of the crop residue that allows the invention to effectively and efficiently destroy the weed seeds found in the crop residue.

[70] Figure 1 illustrates an apparatus 10 used for processing crop residue according to a preferred embodiment of the invention. The apparatus 10 comprises an elongate housing 12. The elongate housing 12 is shaped in the form of two parallel longitudinally intersecting partial cylinders 14a, 14b which may be connected at a pair of internal walls 16a, 16b. This shape allows for a pair of rotors 24, 26 to be housed within the elongate housing 12, so that the interior wall of the elongate housing 12 approximates the outer dimensions of the rotors 24, 26 and follows the orbit of a tip of the rotor 24, 26 when rotating. Additionally, the elongate housing 12 is shaped so that the rotors 24, 26 will not come into contact with the interior wall of the elongate housing 12.

[71] The elongate housing 12 has an opening at one end, defining an inlet 20 for receiving the crop residue, and an opening at the other end, defining an outlet 22 for discharging the crop residue. The inlet 20 may be at an end of the housing, or it may be in an opening in the one or both internal walls 16a, 16b. The gap between the internal walls 16a, 16b forms a passageway 18 which allows material from each cavity of the partial cylinders 14a, 14b to travel from one to the other. The interior wall of the elongate housing 12 is further shaped to encourage crop residue passing through the elongate housing 12, to initially travel towards the interior wall and travel orbitally around the interior wall. The crop residue is able to transition between the two parallel partial cylinders 14a, 14b through the passageway 18.

[72] In another embodiment, the elongate housing 12 may be shaped in a form comprising a single complete cylinder with only one rotor. In a further embodiment, the elongate housing 12 may be shaped in the form comprising more than two partial cylinders connected together along with corresponding rotors. [73] It will be appreciated by a person skilled in the art that the apparatus 10 may have an exterior of any suitable shape or dimension. Additionally, the partial cylinders may be of different diameters.

[74] The rotors 24, 26 extend axially in the elongate housing 12 and are aligned parallel to each other in their respective partial cylinders 14a, 14b. Each of the rotors 24, 26 are comprised of a plurality of radially extending impact members 28a, 28b, 28c, 28d, 28e, 28f, in the form of impact bars, which are mounted on a hub 30, 32 of each shaft 34, 36. Preferably the bars are blunt and intended to smash seeds, rather than sharp for cutting. In this example, the impact members 28a, 28b, 28c, 28d, 28e, 28f are arranged as repeating sets of three impact members, such as the sets defined by impact members 28a, 28b, 28c and 28d, 28e, 28f as seen in Figure 1 . This arrangement has each impact member at a different angle to the others, but spaced appropriately along the shaft 34, 36 so that the centre of mass is substantially placed on the shaft axis to minimise vibration. It will be appreciated that the rotation of the impact members will induce a rotational airflow in the housing.

[75] A blower is provided so as to move air through the housing from the inlet 20 to the outlet 22. In this embodiment the shaft axis coincides with an axis of a blower in the form of a fan. This provides the advantage of increasing axial airflow through the housing 12 and increasing the chances of the impact members 28a, 28b, 28c, 28d, 28e, 28f interacting with crop residue moving through the elongate housing 12. It would be appreciated by a person skilled in the art that any number of impact members or sets of impact members may be mounted on the shaft 34, 36. Additionally, it would be appreciated that the impact members may be of any suitable shape.

[76] In an embodiment, there are two integrally formed impact members mounted on the hub, wherein the impact members are at 180° to each other. It would be appreciated by a person skilled in the art that any number of impact members may be mounted on the hub.

[77] In an embodiment, the number of radially extending impact members may vary along the length of the shaft.

[78] In an embodiment, each consecutive impact member is at an angle of 60 ° to the previous impact member. [79] In an embodiment, each of the impact members have equal axial spacing from another. In an example, this axial spacing is 50 mm between each of the impact members.

[80] In an embodiment, the hub is hexagonal in shape. It would be appreciated by a person skilled in the art that the hub may be of any suitable shape to key the impact members to the hub.

[81] The impact members 28a, 28b, 28c, 28d, 28e, 28f are configured to rotate with the shafts 34, 36 and impact against the crop residue that is received in the inlet 20. As the crop residue travels from the inlet 20 to the outlet 22, the impact members 28a, 28b, 28c, 28d, 28e, 28f impact against the material of the crop residue. Airflow created from the rotors 24, 26 or an external source (such as a fan) urges the lighter material comprising a relatively larger portion of the crop residue, such as the chaff, towards the outlet 22. This results in the lighter material being urged through the elongate housing 12 closer to the axis of rotation, wherein it is subjected to lower impact member speeds as a result of being closer to the rotational centre. Further, less aerodynamic material such as chaff, that is shaped to catch more of the airflow will tend to be blown through the housing 12 more quickly than material, such as a weed seed, is less inclined to be caught by the airflow. The less aerodynamic material will have less time to be acted upon by the impact members due to flow rate through the housing 12. Conceptually, weed seeds are generally denser material than chaff. The denser material comprising a relatively smaller portion of the crop residue, predominantly the weed seeds, tends to be retained in the elongate housing 12 as it is less readily urged by the rotational airflow produced by the rotors 24, 26 and the axial airflow produced by the blower. Additionally, the denser material is flung centrifugally to the inside wall of the elongate housing 12, wherein airflow may be reduced due to surface friction. The denser material then travels orbitally along the inside wall in a direction towards to the outlet 22. As the denser material travels along the inside walls, it will transition from the inside wall of one of the partial cylinders 14a, 14b to the other via the passageway 18. During its transition through the passageway 18, the denser material will be directed into the path of the outermost edges of the impact member 28a, 28b, 28c, 28d, 28e, 28f on the adjacent rotor 24, 26 moving in a transverse direction, subjecting the denser material to an impact with substantial force. This results in the denser material being damaged and/or reduced to smaller fragments of less mass. This process will repeat so that the denser material will be subjected to more impacts from the impact members 28a, 28b, 28c, 28d, 28e, 28f until reduced to fragments that are comparable to the lighter material of the crop residue. These fragments will then be increasingly urged by the airflow towards the outlet 22 due to the reduction in mass and increase in surface area. It would be appreciated by a person skilled in the art that the rotors 24, 26 typically rotate in the same direction to ensure that the plurality of radially extending impact members 28a, 28b, 28c, 28d, 28e, 28f of each rotor 24, 26 travel in orbitally opposing directions when the tips are close to each other. However, in another embodiment the rotors 24, 26 may rotate in opposite directions.

[82] The impact members 28a, 28b, 28c, 28d, 28e, 28f are spaced along the length of the shafts 34, 36 so to impart a desired degree of orbital motion and subsequent impact to crop residue at any position within the elongate housing 12. Additionally, the impact members 28a, 28b, 28c, 28d, 28e, 28f are appropriately spaced so that the tips of the impact members 28a, 28b, 28c, 28d, 28e, 28f are separated by a small distance 38 located within the passageway 18.

[83] Figure 2 illustrates another embodiment of the apparatus 10, wherein the impact members 28a, 28b, 28c, 28d, 28e, 28f may be appropriately spaced and the shafts 34, 36 may be appropriately staggered in relation to each other to enable the orbital paths of the impact members 28a, 28b, 28c, 28d, 28e, 28f to overlap in an area of interaction. The advantage provided by the overlapping impact members 28a, 28b, 28c, 28d, 28e, 28f is the increased chance of crop residue transitioning from a partial cylinder 14a, 14b to the other, being struck by the impact members 28a, 28b, 28c, 28d, 28e, 28f.

[84] In a further embodiment, one or more of the impact members 28a, 28b, 28c, 28d, 28e, 28f may be of any other shape or dimension, such as the form of a blade, as long as it achieves efficacy and is dimensioned so as to be safely contained within the elongate housing 12. In an example the impact members are in the form of bars with a diameter of 475 mm. In another example, the impact members are in the form of blades with a diameter of 500 mm.

[85] The rotors 24, 26 may rotate at any speed to achieve efficacy. Additionally, the rotors 24, 26 may be rotating at the same speed or at independent and or variable speeds. In an example, both rotors 24, 26 may rotate at a variable speed ranging from 1 ,000 to 1 ,500 revolutions per minute (rpm). In another example, one rotor 24 may rotate at a fixed speed of 1 ,000 rpm while the other rotor 26 may have a variable speed ranging from 1 ,000 to 1 ,500 rpm. In a further example, both rotors 24, 26 may rotate at a preferred variable speed ranging from 800 to 2,000 rpm. [86] In an embodiment, the elongate housing 12 may be inclined so that the outlet 22 is elevated higher than that of the inlet 20. By elevating the elongate housing 12, the denser material of the crop residue tends to be retained in the elongate housing 12 due to gravity. This provides the advantage of subjecting the denser materials to more impacts from the impact blades 28a, 28b, 28c, 28d, 28e, 28f. In an example, the elongate housing 12 is inclined at an angle of 5° to the horizontal. In another example, the elongate housing 12 is inclined at a suitable angle, such as an angle of 10°, 15°, 20°, 25° or 30° to the horizontal. In a further example, the elongate housing 12 is inclined at a preferred angle, such as an angle of 45°, 60°, 75°, 80°, 85° or 90° to the horizontal.

[87] In an embodiment, the outlet 22 may have means of spreading the processed crop residue that is discharged. Additionally, the outlet 22 may have means of further projecting the processed crop residue or reducing the projection of the processed crop residue.

[88] Figure 3 illustrates the apparatus 10 having a pitched blade 40 mounted to the shaft 34, 36 and located at the entrance of the inlet 20 of the elongate housing 12. The pitched blade 40 is used as a fan or blower to produce axial airflow, thereby urging the crop residue to move through the elongate housing 12. It would be appreciated by a person skilled in the art that more than one pitched blade 40 may be mounted throughout the length of the rotor 24, 26 to create additional airflow to further urge crop residue to move through the elongate housing. Additionally, it would be appreciated that the pitch of the pitched blade 40 may be variable.

[89] In an embodiment, an independent blower may be located before or at the inlet 20 of the elongate housing 12 to produce axial airflow for urging crop residue to move through the elongate housing. The blower may be any conventional blower, such as by way of example, a centrifugal fan.

[90] Figure 4 illustrates the apparatus 10 being mounted, inclined to the horizontal, to a wheeled chassis 41 to form a system with a mechanical harvester (not shown). The wheeled chassis 41 comprises a frame 42, a pair of wheels 44a, 44b and a means of transporting crop residue 46 from the mechanical harvester to the inlet 20 of the main body 12 for processing by the apparatus 10. In this example, the means of transporting crop residue 46 is in the form of a conveyor belt system. It would be appreciated by a person skilled in the art that any conventional means for depositing the crop residue into the inlet 20 may be used. Additionally, in this example the apparatus 10 has a means of distributing the processed crop reside in the form of a spreader 48. [91] In another embodiment, the apparatus may be mounted directly to the mechanical harvester. Figure 5 illustrates an example of the apparatus 10 being mounted directly to a mechanical harvester at a crop residue output 50. The apparatus 10 includes the spreader 48 which is mounted to the housing 12 at the outlet 22. The spreader 48 comprises a spreader housing 52, of substantially the same shape as that of the elongate housing 12, and a roof 54. The spreader housing 52 has a pair of outlets 56a, 56b for distributing the processed crop residue.

[92] Figure 6 shows the internal components of the spreader 48. In this example, the spreader 48 further comprises a pair of barriers 58a, 58b located at the base of the spreader 48 wherein it is mounted to the outlet 22 of the elongate housing 12. The pair of barriers 58a, 58b extend radially inwards from the inner wall of the spreader housing 48, to define a pair of gaps 60a, 60b that receives the processed crop residue from the outlet 22. The role of the pair of barriers 58a, 58b is to retain the denser material of the crop residue, which might not have been fully processed by the rotors 24, 26, in the housing 12. In practice, the denser material being weed seeds, which has escaped destruction by the rotors 24, 26, are trapped within the elongate housing 12 and are not distributed into the crop fields to germinate until they are broken down in size and weight so as to escape through the gaps 60a or 60b. The processed crop residue which passes through the gaps 60a, 60b are contained in the space defined by the spreader housing 52 and the roof 54. Housed within this space, are a plurality of integrally formed transverse arms 62a, 62c, which in this embodiment are at 180° to each other, which are engaged to and radially extend from the shafts 34, 36. A plurality of paddles 64a, 64b, 64c, 64d are connected to the ends of the transverse arms 62a, 62b, which are used to urge the processed crop residue towards the outlets 56a, 56b as they rotate about an axis parallel to the shafts 34, 36. It would be appreciated that the transverse arms need not be integrally formed and may be comprised of a plurality of transverse arms.

[93] Figure 7 shows the cover 100 covering the inlet 20 to the elongate housing 12. The cover serves to direct the crop residue towards the rotors by having the rotors surrounded by apertures 102 centred so that the rotor centre is located in the centre of the aperture. The cover 100 is removable, being fastened by a number of screws.

[94] Figure 8 shows an enlarged view of Figure 7, where the impact members 28a - 28f are clearly viewable as being inline between one shafts 36 impact member to the second shafts 34 impact member. The impact members 28a - 28f between rotors 24, 26 are also clearly viewable as being separated by a marginal gap, so that they do not clash onto each other during rotation.

[95] Figure 9 shows the internal components of the augers 1 10, 120 within respective bins 1 12, 122 at the inlet 20 of the elongate housing 12. The augers 1 10, 120 direct the crop residue toward the inlet 20 of the elongate housing 12. The augers are located in front of the cover 100 and are positioned to be inline and centred with the shafts 34, 36 of the elongate housing 12.

[96] Figure 10 shows a side view of the inlet 20 of the apparatus and the elongate housing 12 and Figure 1 1 shows a cross-sectional view of the apparatus showing the impact members 28a - 28f, the paddle 130 which can be pitched so as to function as the pitched blade 40. The paddle 130 may also act as a blower. Figure 1 1 further shows the augers 1 10, 120 (120 hidden from view), the shafts 34, 36 (36 hidden from view) and the elongate housing 12.

[97] The method of operation and use of the apparatus 10 used for processing crop residue will now be described in more detail.

[98] The apparatus 10 processes the crop residue by receiving the crop residue in the inlet 20 of the elongate housing 12 and subjecting the crop residue to impacts from a plurality of rotating radially extending impact members 28a, 28b, 28c, 28d, 28e, 28f. The plurality of radially extending impact members 28a, 28b, 28c, 28d, 28e, 28f are rotated via the rotation of the shaft 34, 36 in which the impact members are mounted to. The rotation of the impact members 28a, 28b, 28c, 28d, 28e, 28f in combination with the shape of the elongate housing 12 and a blower, in the form of the pitched blade 40 or an external blower, causes the lighter material of the crop residue, in the form of straw and chaff, to be urged to move through the elongate housing 12 to the outlet 22 so that the lighter material is subjected to less impacts. The denser material of the crop residue, including weed seeds, tends not to be urged to move through the elongate housing 12, thereby subjecting the denser material to more impacts. This results in the denser material being reduced into smaller fragments, devitalising the weed seeds. Subsequently, the denser material is reduced to fragments comparable to the lighter material and is urged towards the outlet 22. After being subjected to these impacts, the processed crop residue is then discharged from an outlet 22 of the elongate housing 12. [99] Prior to use, the apparatus 10 may start at a position wherein the elongate housing 12 lays flat in a horizontal position. However, the elongate housing 12 may be in a different starting position. The elongate housing 12 is then inclined so that the outlet 22 is elevated higher than that of the inlet 20. The elongate housing 12 is then fixed at the desired angle of inclination, before initiating rotation of the rotors 24, 26 and feeding the crop residue into the inlet 20. This results in increased efficiency of denser material destruction according to the angle of inclination. In an example, the apparatus 10 was used to process rye grass seeds at various angles of inclination and rotor speeds. The results are shown in the table below.

[100] The apparatus is intended to be arranged as part of a system comprising a mechanical harvester. The apparatus may be mounted on a wheeled chassis to be towed behind the mechanical harvester, or mounted directly on the mechanical harvester. The mechanical harvester has means for feeding crop residue to the inlet 20 of the elongate housing 12 so that the apparatus may process the crop residue.

[101] Modifications may be made to the present invention within the context of that described and shown in the drawings. Such modifications are intended to form part of the invention described in this specification.