Note: Descriptions are shown in the official language in which they were submitted.
WO 2023/023807
PCT/AU2022/051035
AN IMPACT ROTOR AND ASSOCIATED MATERIAL PROCESSING SYSTEM
TECHNICAL FIELD
An impact rotor and an associated material processing system are disclosed.
The material
processing system has particular, but not exclusive, application for the
devitalisation of weed
seeds and fragmentation of organic matter. In such applications the rotor and
processing
system may be mounted on a combine harvester to process a chaff stream.
BACKGROUND ART
Weeds and weed control are, and always have been, one of the biggest
constraints and costs to
grain production. Weeds are a perpetual problem that limits the food
production capacity of
agricultural area around the globe. Weeds compete with the cultivated crops
for water, sunlight
and nutrients. In the past 50 years there has been a shift from tillage being
the most important
method to control weeds to herbicides being the most important tool to control
weeds.
Herbicides in general provide much better control of weeds than tillage
methods and do not
have the major issues of soil erosion, moisture loss and breakdown of soil
structure. The
widespread use and reliance of herbicides has resulted in weeds evolving
resistance to
herbicides. The herbicide resistance is now widespread and presents one of the
biggest threats
to global food security. Strategies to provide non-chemical weed control to
complement
herbicides are now paramount to reduce the selection pressure for herbicide
resistance. One
particular method of significant renewed interest is destroying weed seeds at
harvest time to
interrupt the weed cycle.
Many in-crop weeds share a similar life cycle to harvested crops. Once a crop
matures and is
harvested, there is a broad range of weeds that have viable seeds remaining on
the plant above
the cutting height of the harvester. These weeds enter the harvester and their
seeds either end
up in a grain tank, out with straw residues, or out with chaff residues. There
are a range of
factors that determine where a weed seed will end up at harvest time including
moisture
content, maturity, and harvester setup. A major factor that determines where a
seed ends up is
the aerodynamic properties of the seeds or its terminal velocity. Often a weed
seed is much
lighter than the grain being harvested. Crop cleaning systems used during
harvesting employ a
winnowing action to remove light chaff material from the heavier grain using
airflow and
mechanical sieving. The light weed seeds are caught in the wind and can exit
the back of the
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harvester sieve. The residues and contained weed seeds are then spread on the
ground to be a
problem for next year. The residues also contain a proportion of grain being
harvested that
could not be separated by the harvester. This grain loss has the potential to
become a volunteer
weed after harvest. There is an opportunity to intercept and destroy weed
seeds in the residues
before allowing them to become a problem for next year's crop.
One method to destroy these weed seeds is to use a milling technology. Milling
technology has
been used for particle size reduction of a range of feedstock for over a
century. Milling
technology can be separated into crushing and impact technology.
One system for seed destroying mill technology is described in WO 2018/053600
(Berry). Berry
describes a weed seed processing system in the form of a multistage hammer
mill. This mill has
a plurality of milling stages arranged concentrically about each other. The
plurality of milling
stages is arranged so that substantially all material in a first inner most of
the milling stages
passes through all subsequent adjacent milling stages. The milling stages
include a first milling
stage and a second milling stage. A central feed opening enables material flow
into a primary
impact zone of the first milling stage. The first milling stage has an impact
mechanism and a first
screen arrangement. The impact mechanism rotates about a rotation axis. The
first screen
arrangement is disposed circumferentially about and radially spaced from the
impact
mechanism and is provided with a plurality of apertures through which impacted
material of a
first size range can pass. The second milling stage has a second arrangement
disposed
circumferentially about and radially spaced from the first screen arrangement
and a circular
array of impact elements disposed between the first screen arrangement and the
second screen
arrangement.
This system has proved to be effective in the field and installed on combines
in many countries.
The disclosed impact system was developed with the view to enhancing the
performance
material processing systems including, though not limited to, the above
described system in
Berry.
The above references to the background art do not constitute an admission that
the art forms a
part of the common general knowledge of a person of ordinary skill in the art.
The above
references are also not intended to limit the application of the impact rotor
as disclosed herein.
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SUMMARY OF THE DISCLOSURE
In one aspect there is disclosed an impact rotor for a material processing
system and capable of
rotating about a rotation axis comprising:
a base plate;
a first circular array of hollow impact bars disposed about the rotation axis,
wherein one end of
each impact member is coupled to the base plate;
each impact bar is provided with an outer surface being coated with hard
facing; and
a first support ring coupled to an opposite end of each impact bar.
In one embodiment the one end of each impact bar is welded to the base plate.
In one embodiment the opposite end of each impact bar is welded to the support
ring.
In one embodiment the impact rotor comprises a second circular array of impact
bars disposed
about the rotation axis and co-centric with the first circular array, each
impact bar of the second
circular array comprising a hollow bar provided with an outer surface and
having one end
coupled to the base plate; and a second support ring coupled to an opposite
end of each impact
bar of the second circular array.
In one embodiment at least some of the hollow bars have a square or circular
cross-sectional
shape.
In a second aspect there is disclosed an impact rotor for a material
processing system capable
of rotating about a rotation axis comprising:
a base plate;
a first circular array of impact bars disposed about the rotation axis, each
impact bar being
made of a plastics material;
a first support ring; and
for each impact bar, one or more mechanical fasteners arranged to couple the
impact bar to the
base plate and the first support ring.
In one embodiment the one or more mechanical fasteners comprise at least one
fastener that
extends wholly through the impact bar and connects the first support ring to
the base plate.
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In one embodiment the base plate is made from a metal or metal alloy.
In one embodiment the first support ring is made from a metal or metal alloy.
In one embodiment the impact rotor comprises a second circular array of impact
bars disposed
about the rotation axis and co-centric with the first circular array, each
impact bar of the second
circular array being made of a plastics material;
a second support ring coupled; and
for each impact bar of the second array, one or more mechanical fasteners
arranged to couple
the impact bars to the base plate and the second support ring.
In one embodiment the one or more mechanical fasteners comprise at least one
fastener that
extends wholly through at least one of the impact bars of the second array and
connects the
second support ring to the base plate.
In one embodiment of the frist or second aspects the impact rotor comprises
one or more
scrapers supported on an upper side of the base plate and outside of a
radially outermost
circular array of impact bars.
In one embodiment base plate comprises for each scraper, a radially extending
lug on which an
associated scraper is mounted.
In a third aspect there is disclosed a material processing system comprising:
an impact rotor according to the first or second aspects;
an impact mechanism connected to the base plate, the impact mechanism centered
on the axis
and having one or more radially extending hammers or flails; and
a first stator structure surrounding the axis and located between the axis and
the first circular
array, the first stator structure comprising one or more first surface
portions and a plurality of
holes or gaps in or between the surface portions; and
wherein material entering the material processing system is impacted by the
impact mechanism
and accelerated in a radial outward direction onto the first stator structure
wherein the material
is impacted on the first surface portions or passes through the holes or gaps.
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In one embodiment the impact processing system comprises a second stator
structure
surrounding the first circular array, the second stator structure comprising
one or more second
surface portions and a plurality of holes or gaps in or between the second
surface portions,
wherein material passing through the first stator structure and impacted by
the first array is
accelerated in a radial outward direction onto the second stator wherein the
material is impacted
on the second surface portions or passes through the holes or gaps in between
the second
surface portions.
In one embodiment the impact processing system comprises a third stator
structure surrounding
the second circular array, the third stator structure comprising one or more
third surface portions
and a plurality of holes or gaps in or between the third surface portions,
wherein material
passing through the second stator and impacted by the second array is
accelerated in a radial
outward direction onto the third stator wherein the material is impacted on
the third surface
portions or passes through the holes or gaps in or between the third surface
portions.
In one embodiment the first stator structure comprises a one-piece element
formed as, or into, a
ring like structure.
In one embodiment the second stator structure comprises a one-piece element
formed as, or
into, a ring like structure.
In one embodiment the third stator structure comprises a one-piece element
formed as, or into,
a ring like structure.
In one embodiment any one or more of the stator structures is formed with one
or more parts of
increased width in a circumferential direction.
In a fourth aspect there is disclosed a material processing system comprising:
an impact rotor according to the first or send aspects;
an impact mechanism connected to the base plate, the impact mechanism centered
on the axis
and having one or more radially extending hammers or flails; and
a stator arrangement comprising a top plate, at least one stator structure
comprising one or
more stator segments having opposite ends, and a respective stator ring for
each of the at least
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one stator structure, wherein one end of the one or more stator segments is
attached to the top
plate and an opposite end of the one or more stator segments is attached to
the first stator ring;
wherein the top plate is co-centric with the base plate and spaced from the
base plate by the
stator structure.
In one embodiment each stator structure comprises a single segment wherein the
single
segment is a one piece planar element in which holes or gaps are formed and
the planar
element is rolled into a ring like configuration.
In one embodiment the holes or gaps are arranged in a matrix of columns and
rows with axially
extending parts of the element separating adjacent columns of holes or gaps,
and
circumferentially extending parts of the element separating adjacent the rows
of holes or gaps
and wherein some of axially extending parts are wider in a circumferential
direction than other
axially extending parts.
In one embodiment each stator structure comprises a plurality of segments,
each segment
including a screen provided with a plurality of holes respective blades on
opposite sides of the
screen wherein the blades lie in substantially radial planes with reference to
the axis.
In one embodiment for at least one element the screen is arranged to lie
inboard of radially
inner edges of the blades.
In one embodiment for at least one element the screen is arranged to inboard
of radially outer
edges of the blades.
In one embodiment each stator structure comprises a plurality of segments
which are evenly
spaced about the axis, each blade orientated to lie in substantially radial
planes with reference
to the axis.
In a fifth aspect there is disclosed a material processing system comprising:
an impact rotor according to the frist or second aspect;
an impact mechanism connected to the base plate, the impact mechanism centered
on the axis
and having one or more radially extending hammers or flails; and
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a plurality of interchangeable stator arrangements wherein each stator
arrangement comprises:
a top plate, at least one stator structure comprising one or more stator
segments having
opposite ends, and a respective stator ring for each of the at least one
stator structure, wherein
one end of the one or more stator segments is attached to the top plate and an
opposite end of
the one or more stator segments is attached to the first stator ring; and
wherein each of the
plurality of stator arrangements have respective stator arrangements of
different configuration to
enable changing of the stator arrangements to suit a characteristic of
material being processed
by the system.
BRIEF DESCRIPTION OF THE DRAWINGS
Notwithstanding any other forms which may fall within the scope of the mill as
set forth in the
Summary, specific embodiments will now be described, by way of example only,
with reference
to the covering drawings in which:
Figure 1 is a perspective view of one embodiment of the disclosed impact
rotor;
Figure 2 is a side view of the impact rotor shown in Figure 1;
Figure 3 is a plan view of the impact rotor shown in Figure 1;
Figure 4 is a perspective view of a second embodiment of the disclosed impact
rotor;
Figure 5 is a representation of a portion of one form of a material processing
system
incorporating embodiments of the disclosed impact rotor, a central impact
mechanism, and a
first stator arrangement;
Figure 6 is a radial section view of the material processing system shown in
Figure 5;
Figure 7 is a representation of the first stator arrangement incorporated in
the material
processing system;
Figure 8 is a perspective view from below of second form of stator arrangement
that may be
used in a material processing system incorporating embodiments of the
disclosed impact rotor;
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Figure 9 is a perspective view from the side of the stator arrangement and
material processing
system shown in Fig 8;
Figures 10-12 depict different views of third form of stator arrangement that
may be used in
material processing system incorporating embodiments of the disclosed impact
rotor; and
Figure 13 depicts a fourth form of stator arrangement that may be used in
material processing
system incorporating embodiments of the disclosed impact rotor.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
Referring to Figs 1-3 a first embodiment of the disclosed impact rotor 10a
which is suitable for
use in for a material processing system, such as, but not limited to a
multistage hammer mill as
exemplified in the above referenced international publication WO 2018/053600
(Berry), the
contents of which are incorporated herein by way of reference. The impact
rotor 10a is capable
of rotating about a rotation axis 12. The impact rotor comprises a base plate
14 and a first
circular array 16a of hollow impact bars 18 which are disposed about the
rotation axis 12. One
end 20 of each impact bar 18 is coupled to the base plate 14. Each impact
member 18 has an
outer surface 22 which is coated with hard facing. The impact rotor 10a also
has a first support
ring 24a that is coupled to an opposite end 26 of each impact bar 18.
In one embodiment the impact bars 18 can be made from a mild steel tube hard-
faced, for
example by using a laser process with a tungsten carbide cladding.
The base plate 14 and the first ring 24 are also made of metal. This allows
the impact bars 18 to
be welded to the base plate 14 and 24.
The impact bars 18 may have a variety of cross-sectional shapes including, for
example, and
not limited to, square or circular. A further benefit is derived where the
cross-sectional shape is
symmetrical about a plane P (shown in Fig 3) that passes through a geometric
center of the
impact bar 18 and the rotation axis 12. This benefit arises when a material
processing system
(such as a multistage hammer mill of a type described in WO 2018/053600)
incorporates two
counter rotating and adjacent impact rotors 10a. As will be understood by
those skilled in the
art, when a processing system has a rotating impact rotor, the leading edge of
impact surfaces
with reference to the direction of rotation is subjected to substantially
greater wear than the
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trailing edge. When there are two mills with counter rotating impact rotors,
the worn leading
edges of the respective rotors are on opposite sides of the impact bars, as
are their respective
non, or less, worn trailing edges. By swapping over the impact rotors of the
two mills so that
they are rotated in the opposite direction to that previously endured, the
less worn trailing edges
now become the leading edges. This effectively extends the working life of the
impact rotor.
Alternately the benefits of this extended life may be realised by the use of
(a) a serpentine belt,
and associated idlers and pulleys; or (b) a reversing gearbox, which can be
used to reverse the
direction of rotation of the impact rotors 10a.
This embodiment of the impact rotor 10a also includes a second circular array
16b of hollow
impact bars 18 disposed about the rotation axis 12 and co-centric with the
first circular array
16a. One end 20 of each impact bar 18 in the second array 16b is coupled to
the base plate 14.
Each impact member 18 has an outer surface 22 which is coated with hard facing
the same as
for the first circular array 16a. A second support ring 24b is coupled to an
opposite end 26 of
each of the impact bars 18 of the second array 16b.
The end 20 of the impact bars 18 in the second array 16b are welded to the
base plate 14.
Similarly, the opposite end 26 of the impact bars 18 in the second array 16b
are welded to the
second support ribs 24b.
Owing to the hollow nature of the impact bars 18, the weight of the impact
rotor 10a is
significantly lighter to an equivalent impact rotor with solid impact bars. By
way of comparison
with the impact rotors used in the commercially available mill described in WO
2018/053600, an
embodiment of the disclosed impact rotor 10a may weigh up to about 55% less.
More
specifically an embodiment of the disclosed impact rotor10 having 25 mm square
section hollow
bars 18 weighs approximately 24 kg compared with, about 43 kg for the impact
rotor in
aforementioned commercially available. The reduction in weight reduces the
inertia of the
impact rotor 10a thereby reducing the load on an associated drive system at
start-up. The
weight reduction also makes it easier to handle the material processing system
during
installation and maintenance, as well as reducing the: weight added to the
combine; and, the
startup torque on the combine engine due to a lower moment of inertia.
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Figure 4 illustrates an alternate embodiment of the impact rotor, designated
as 10b. In
describing the embodiment of the rotor 10b same reference numbers will be used
as for the
embodiment of the rotor 10a, described above. The impact rotor 10b is of a
generally similar
configuration to that of the first embodiment but the impact bars 18 are made
from a hard
plastics material, such as but not limited to ultra-high-molecular-weight
polyethylene; high
density polyethylene; or, polyetheretherketone. The impact bars 18 are
arranged as an inner
array 16a and an outer array 16b. The impact bars 18 are coupled at one end to
the base plate
14. Each array has an associated support ring 24a, 24b to which the bars 18
are coupled. The
base plate 14 and the support rings 24 in this embodiment are made of a metal
or metal alloy.
Mechanical fasteners, such as bolts 30 are used to connect the bars 18 to the
base plate 14
and the respective support rings 24. In one embodiment a single mechanical
fastener/bolt 30
may be used to couple a corresponding impact bar 18 its support ring 24 and
the base plate 14.
In this arrangement the bolt 30 extends wholly through the corresponding
impact bar 18. The
impact bars 18 can be formed with the same cross-sectional shape as described
in relation to
the impact bars 18 of the first embodiment.
The impact rotor 10b provides the same benefits in terms of its lightweight
and lower inertia as
the first embodiment of impact rotor 10a.
The base plate 14 of either embodiment of impact rotor 10a, 10b (hereinafter
referred to in
general as "impact rotor(s) 10") may be provided with one or more scrapers 39.
The scrapers 39
are located on an upper face of the base plate 14 and radially outside of an
outer most circular
array of impact bars 18. Moreover, the base plate 14 is provided with radially
outward extending
lugs 15 on which respective scrapers 39 are coupled.
Figures 5-7 illustrate one embodiment of a stator arrangement S1 that may be
used with
embodiments of the impact rotor 10a, 10b to construct a material processing
system 40 such as
a multistage hammer mill.
Figures 5 and 6 illustrate an impact mechanism 41 connected to the base plate
14. In this
embodiment the impact mechanism 41 forms part of the impact rotor 10. The
impact
mechanism 41 has a hub 37 that is centered on the rotation axis 12 and fixed
to the base plate
14. Therefore, the impact mechanism 41 and hub 37 rotate together with the
base plate 14, and
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the impact bars 18. A plurality of radially extending hammers or flails 42 are
coupled to the hub
37. The flails 42 are pivotally coupled to the hub 37 by respective pivot pins
43 that are parallel
to but offset from the rotation axis 12.
The stator arrangement S1 includes a first stator structure 44a that surrounds
the axis 12 and is
located between the axis 12 and the first circular array 16a of impact bars
18. The first stator
structure 44a provides a surface or surfaces against which material is
impacted by the impact
mechanism 41. The stator structure 44a also has a plurality of holes or gaps
45 through which
impacted material can pass if, or when their size is reduced to be, small
enough to pass
through. In this embodiment the first stator structure 44a is in the form of a
mesh screen or
perforated plate fabricated from a plurality of (in the illustrated embodiment
three) mesh
segments 46. A plurality of axially extending supporting ribs 47 is provided
on a radially outer
side of the segments 46 immediately behind each of the screen arrangements 20
in the radial
direction. The ribs 47 are evenly spaced circumferentially about the first
stator structure 44a and
provide structural support for the stator structure 44a. Also, there is a 48
space between
mutually adjacent segments 46. The space(s) 48 allows the passage hard
materials such as
stones or metal bodies to minimise the risk of damage to the stator structure
44a.
A top plate 50 to which the stator structures 44 are attached has a central
opening 52. The
central opening 52 constitutes an inlet for material into the processing
system 40. The material
that enters the material processing system 40 through the opening 52 is
impacted by the impact
mechanism 41 and accelerated in a radial outward direction toward the first
stator structure 44a.
This material is: impacted by the impact mechanism 41 and against the surface
of the segments
46 resulting in fragmentation, crushing or milling to particles of a size that
passes through the
holes or gaps 45.
In this embodiment there is a second stator structure 44b, and third stator
structure 44c. Each of
the stator structures 44b and 44c are of the same or similar construction,
configuration and
function as the first stator structure 44a. However, the diameters of the
second and third stators
are progressively larger. Also, optionally the holes or gaps 45 in the
segments of the stator
structures 44b, 44c may be formed to be progressively smaller with increasing
distance from the
axis 12.
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The second stator structure 44b surrounds the first array 16a of the impact
mechanism 10. The
third stator structure 44c surrounds the second array 16b of the impact rotor
10. The impact
rotor 10 together with the impact mechanism 41 are rotated together as a
single unit. Material
entering the material processing system 40 through the opening 52 is thus
subjected to multiple
impacts as it travels to an outlet (not shown in this embodiment) which is
formed in a housing
(also not shown in this embodiment) that surrounds the impact rotor and stator
arrangement.
When this material is chaff containing weed seeds the weed seeds are
devitalised due to being
fragmented, crushed or milled.
The scraper 39 on the impact rotor 10/ base plate 14 assists in drawing
material through the
material processing system 40. The air is drawn from the inlet 52, and through
the stator
structures 44a-44c. The scrapers 39 also propel the material toward an outlet
before it falls to
the base plate 14. This is in contrast to having scrapers on an under surface
of the plate 40
which may have an adverse effect of drawing in air from below the base plate
and provide no
benefit to material flow through the material processing system.
Figures 8 and 9 show an alternate stator arrangement S2 comprising a plurality
of stator
structures 44ax-44cx (hereinafter referred to in general as "stator 44ix" or
"stators 44ix") that
may be used with the above-described impact rotors 10 to form a material
processing system
40. The same reference numbers as used for denoting features in Figs 5-7 are
used to denote
the same feature in the state arrangement S2 shown in Figures 8-9.
The primary differences with the embodiment shown in Figures 5-7 are that in
the stator
arrangement S2:
= each of the stators 44ix is formed as a single piece element rather than
a plurality of
separate segments 46;
= there are no supporting ribs 47;
= there are no spaces 48 between adjacent segments (because there are no
segments
46)
The stators 44ix are formed from a one piece planar element, such as but not
limited to, a
rectangular plate of metal, in which the holes or gaps 45 are formed. The
holes or gaps 45 may
be formed for example by stamping or cutting the element. The element is then
rolled into a ring
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with opposite short sides of the plate adjacent each other. Thus, the stators
44ix can be made
for example from one piece of steel formed as or into a ring like structure.
Also, each stator 44ix
is formed with enlarged holes 48x that act in a similar way to the spaces 48
of the earlier
embodiment formed between separate segments 46.
Each stator 44ix may be formed with one or more parts of increased width in a
circumferential
direction. More specifically, the stators 44ix can be considered to be in the
form of screens
formed with a matrix of holes 45, 48x arranged in columns and rows. The solid
material of the
screens between the holes forms axially extending parts 49 and
circumferentially extending
parts 51. In some embodiments, not all of the parts 49 are of the same width
in the
circumferential direction. For example, some of the parts 49w are wider than
other parts 49n.
The wider parts 49w are regularly spaced about the screens/stators 44. In the
absence of the
ribs 47 incorporated in the stators of Figs 5-7, support for each stator 44ix
can be provided by
the wider parts 49w. In the embodiments shown in Figs 8 and 9 the thickness of
any one of the
stators is constant in the radial direction. The parts 49w of each stator 44ix
wear more slowly
than the parts 49n and provide structural integrity even when other parts of
the stator may be
worn through.
Forming the stators 44ix in one piece means a simpler manufacture process. In
addition,
processing system 40 comprising the rotor 10 and the stators 44ix can be much
more compact
than the state of the art as the stator elements are far more compact. This
means that the tip
speed of the rotor impact elements is more similar than a less compact
arrangement. Having a
similar tip speed leads to the ability to have more efficient devitalisation
of seeds. If the speed of
impact is too slow, seeds are not damaged, if seeds are struck too fast then
energy is wasted.
The material processing system 40 in Figures 8 and 9 is also shown with a
circumferential side
wall 54, outlet opening 56 and bottom housing wall 58 which together form part
of an outer
housing 60 for the material processing system 40. The housing 60 also has an
upper cover (not
shown) that overlies the plate 50 and is provided with an opening in alignment
with the inlet 52.
In the material processing system 40, the plate 50 and the base plate 14 are
at axially opposite
ends of, and inside, the housing 60.
Material enters through the opening in the housing and the inlet 52 in the top
plate 50. With the
impact rotor 10 rotating, the impact mechanism 41 impacts the material and
accelerates the
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material onto the innermost stator 44ax. The material passes through the holes
45/48 in the
stator 44ax is subsequently impacted by the adjacent rotating impact bars 18
of the first array
16a. These impact bars in turn accelerate the material onto the central stator
44bx, causing
further fragmentation, damage and devitalisation of weed seeds. This material
subsequently
passes through the holes in stator 44bx and impacted by the second array 16b
of impact bars
18. The successive impacts with the elements of the impact rotor 10 and the
stators 44
devitalise weed seeds in the processed chaff. The processed chaff exits
through the outlet
opening 56 and may be spread onto the ground, fed into a straw chopper, or fed
to a spreader.
Figures 10-12 show a third stator arrangement S3 that may be particularly
useful for
incorporation into a material processing system 40 mounted on a combine for
harvesting fibrous
material such as lupins, beans, and peas. The same reference numbers as used
for denoting
features of the stator arrangements Si and S2 are used to denote the same
feature in the stator
arrangement S3 shown in Figures 10-12.
In this embodiment the stator arrangement S3 comprises a plurality of stator
structures 44a-44c
each composed of a plurality of segments 46e having a relatively small arc
length which are
arranged into a plurality of circular stator arrays. The arc length of each
segment 46e may be
between about 10 to 20 , and there may be between about 10 to 20 segments 46e
evenly
spaced about the axis 12. The stator segments 46e are coupled to and retained
between a top
plate 50 and respective stator rings R1-R3. A material processing system 40
may be
constructed using the stator arrangement S3 in conjunction with an impact
rotor which may
include an embodiment of the above described impact rotors 10a and 10b, or a
prior art impact
rotor.
Each stator segment 46e comprises a screen 62 provided with a plurality of
holes 45. The
screen 62 has a generally rectangular configuration. The holes 45 are arranged
in a regular
matrix pattern with vertical columns and horizontal (or circumferential) rows.
The screen lies in
tangent plane relative to the axis 12. In this, but not necessarily all,
embodiments at least one
of the surfaces 66 of the holes 45 may be profiled with a plurality of
serrations or ridges 68
(shown best in Figure 11). This profiling may assist in the damage,
fragmentation, or attrition of
material passing through the stator segments 46e.
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Each segment 46e also includes on opposite sides of the screen 62, blades 64.
The blades 64
extend between and are coupled to the top plate 50 and respective rings R1-R3.
In some
embodiments the plates 64 are also fixed to the screen 62, for example by
welding. The blades
64 are orientated to lie in respective radial planes relative to the axis of
rotation 12.
Each blade 64 is formed with a plurality of edges 70. The edges 70 include
radially inner edges
70i and radially outer edges 70j, but collectively and in general are referred
to as "edge(s) 70".
The edges are exposed to material passing through the stator arrangement S3
providing
aggressive impact edges for the material to promote damage, fragmentation or
attrition to the
material. Each blade 64 is orientated so that its opposite surfaces 72 of
greatest area lie in
radial planes with respect to the axis of rotation 12.
In this embodiment, and as best seen in Figure 11, the screen 62 is arranged
to lie inboard of
the radially inner edges 70i of the blades 64. The edges 70i directly face
material that is
impacted by the impact rotor of an associated material processing system, such
impacted
material being accelerated in a radially out ward direction. Additionally, in
this but not
necessarily all embodiments the screens also lie inboard of the radially outer
edges 70j
Each of the stator segments 46e are circumferentially spaced from each other
leaving spaces
48 for the passage of hard objects that may be entrained in the material being
processed.
Figure 13 illustrates yet a further embodiment of a stator arrangement S4. The
stator
arrangement S4 can be viewed as being substantially the same as the stator
arrangement S3
but with the screens 62 removed. Thus, the stator arrangement S4 comprises
respective stator
structures 44a-44c, each having a plurality of blades 64 orientated so that
their major surfaces
lie in radial planes referenced to the central axis 12. So, in this embodiment
each blade 64 also
constitutes a segment of the corresponding stator structure. One end of each
plate 64 is
coupled to the top plate 50 with the opposite end being coupled to respective
stator rings R1-
R3. The general purpose of the stator S4 when used with embodiments of the
impact rotors
10a, 10b, or indeed prior art rotors, is to form a material processing system
that largely acts as a
material spreader.
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The stator S4 will cause a degree of devitalisation of weed seeds in chaff
passing through the
corresponding material processing system. It is believed that the
devitalisation may
predominantly apply to volunteers seeds.
Significantly, embodiments the present disclosure provide for a "plug and
play" material
processing system in which the stator arrangements S1-S4 can be interchanged
easily and
quickly to suit the type or characteristics of crop being harvested by a
combine. In the event that
no or very little weed seed or volunteers seed devitalisation is required the
stator system S4
may be used with the disclosed or prior art impact rotors. When harvesting a
crop such as
wheat, the stator systems S1 or S2 may be most suitable. When harvesting
fibrous crops such
as lupins, beans or peas stator arrangement S3 may be more suitable. This is
enormously
beneficial
In the claims which follow, and in the preceding description, except where the
context requires
otherwise due to express language or necessary implication, the word
"comprise" and variations
such as "comprises" or "comprising" are used in an inclusive sense, i.e. to
specify the presence
of the stated features but not to preclude the presence or addition of further
features in various
embodiments of the mill and residue processing system as disclosed herein.
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