U.S. patent application number 10/496930 was filed with the patent office on 2005-05-26 for soil based material and method of producing same.
Invention is credited to Kluss, Bill, Neff, Kenneth.
Application Number | 20050111922 10/496930 |
Document ID | / |
Family ID | 3832901 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050111922 |
Kind Code |
A1 |
Neff, Kenneth ; et
al. |
May 26, 2005 |
Soil based material and method of producing same
Abstract
This invention relates to a soil based material for improving
the qualities of the soil. The invention is particularly concerned
with improving load bearing qualities and impact loading qualities
of the soil. The soil based material includes synthetic fibres (5)
scattered throughout the soil matrix (4) and may include additives
such as resilient particle (20) also scattered throughout the soil
matrix (4). The invention also relates to a method and apparatus
for producing the soil based material.
Inventors: |
Neff, Kenneth; (Mr Eliza,
AU) ; Kluss, Bill; (Forest Lake, AU) |
Correspondence
Address: |
Jones Day
222 East 41st Street
New York
NY
10017
US
|
Family ID: |
3832901 |
Appl. No.: |
10/496930 |
Filed: |
January 3, 2005 |
PCT Filed: |
November 26, 2002 |
PCT NO: |
PCT/AU02/01609 |
Current U.S.
Class: |
405/263 |
Current CPC
Class: |
E01C 21/00 20130101;
C09K 17/04 20130101; E02D 3/12 20130101; A01B 79/02 20130101; C09K
17/16 20130101 |
Class at
Publication: |
405/263 |
International
Class: |
E02D 003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2001 |
AU |
PR 9091 |
Claims
1. A soil based material including a soil matrix and synthetic
fibres scattered throughout said matrix.
2. A soil based material according to claim 1, wherein said fibres
are a mixture of mono-fibres and fibrillated fibres.
3. A soil based material according to claim 2, wherein said mixture
of fibres includes substantially even amounts of said mono-fibres
and said fibrillated fibres respectively.
4. A soil based material according to claim 3, wherein each cubic
metre of the soil matrix includes 1 to 6 kilograms of said mixture
of fibres.
5. A soil based material according to claim 4, wherein each cubic
metre of the soil matrix includes approximately 2.6 kilograms of
said mixture of fibres.
6. A soil based material according to claim 1, wherein said fibres
are mono-fibres, and each cubic metre of said soil matrix includes
approximately 17 kilograms of said fibres.
7. A soil based material according to any preceding claim, wherein
biodegradable fibres, in addition to said synthetic fibres, are
scattered throughout said soil matrix.
8. A soil based material according to any preceding claim, wherein
at least some of said fibres have a length in the range 15
millimetres to 20 millimetres inclusive.
9. A soil based material according to any preceding claim,
including at least one additive dispersed throughout the
matrix.
10. A soil based material according to claim 9, wherein said
additive comprises or includes an organic material fertiliser or
wetting agent.
11. A soil based material according to claim 9, wherein said
additive comprises or includes particles of resilient material
scattered throughout the soil matrix.
12. A soil based material according to claim 11, wherein said
particles are approximately 3 millimetres thick, approximately 25
millimetres long, and approximately 20 millimetres wide.
13. A soil based material according to claim 11 or 12, wherein said
particles are formed of polyethylene.
14. A method of producing a soil based material including a soil
matrix and synthetic fibres scattered throughout said matrix,
including the steps of depositing said fibres on the surface of a
body of soil, and mixing said fibres with said body of soil to
achieve a substantially regular dispersion of said fibres
throughout said body of soil.
15. A method according to claim 14, wherein said fibres are caused
to separate prior to being deposited on said body of soil.
16. A method according to claim 15, wherein said separation is
effected by inducing an electrostatic charge in said fibres.
17. A method according to any one of claims 14 to 16, including the
step of mixing particles of a resilient material with the soil
matrix so as to achieve a substantially consistent dispersion of
said particles throughout said matrix.
18. A method according to claim 17, wherein said particles are
mixed with the soil matrix prior to introducing said fibres into
said soil matrix.
19. A method according to claim 17, wherein said particles and said
fibres are simultaneously mixed with said soil matrix.
20. A method of producing a soil based material including the steps
of, moving a mixing chamber over the surface of a body of soil,
causing soil to be lifted from said surface to flow upwards into
said chamber, directing a stream of fibres into said chamber so as
to mix with said upward flow of soil, directing said soil/fibre
mixture to flow downwards within said chamber towards said body of
soil at a position rearwards of said upward flow of soil relative
to the direction of travel of said chamber, and mixing said
soil/fibre mixture within said body of soil.
21. A method according to claim 20, wherein said fibres are caused
to separate prior to being deposited on said body of soil.
22. A method according to claim 21, wherein said separation occurs
before said fibres enter said mixing chamber.
23. A method according to claim 21 or 22, wherein said separation
is effected by inducing an electrostatic charge in said fibres.
24. A method according to any one of claims 20 to 23, wherein an
additive is introduced into said stream of fibres to mix therewith
before said stream enters said mixing chamber.
25. A method according to claim 24, wherein said additive comprises
particles of a resilient material, and both said fibres and said
particles are mixed with said upward flow of soil within said
mixing chamber.
26. A ground surface including a surface layer and a second layer
underlying the surface layer, said surface layer including a soil
matrix and synthetic fibres scattered throughout said matrix, and
said second layer including a soil matrix, synthetic fibres
scattered throughout the soil matrix of the second layer, and
particles of resilient material scattered throughout the soil
matrix of the second layer.
27. A ground surface according to claim 26, wherein said surface
layer is formed of a soil based material according to any one of
claims 2 to 13.
28. A ground surface according to claim 26 or 27, wherein said
second layer is formed of a soil based material according to claim
12 or 13.
29. A ground surface according to any one of claims 26 to 28,
wherein said second layer is interposed between said surface layer
and a base layer.
30. A ground surface according to claim 29, wherein said base layer
is composed of sand or a sand composite.
31. Apparatus for forming a soil based material according to any
one of claims 1 to 13, said apparatus including a delivery system
through which a stream of said fibres is moved, separation means
promoting separation of individual fibres in said stream, and
mixing means operative to mix said fibres within a body of soil
that forms said soil matrix.
32. Apparatus according to claim 31, wherein said separation means
induces an electrostatic charge in said fibres.
33. Apparatus according to claim 31 or 32, including storage means
in which said stream of fibres is deposited downstream from said
separation means, and from which fibres are extracted for delivery
to said mixing means.
34. Apparatus according to claim 31 or 32, wherein said mixing
means includes a mixing chamber for receiving said stream of fibres
downstream from said separation means, and soil engaging means
operative to lift soil from a body of soil beneath said mixing
chamber and cause the lifted soil to mix with said fibres within
said mixing chamber, and said mixing chamber includes flow
directing means that directs the soil/fibre mix to flow downwards
onto said body of soil.
35. Apparatus according to claim 34, including storage means for
containing a body of said fibres, and flow inducing means for
causing fibres to exit said storage means and flow towards said
mixing chamber.
36. Apparatus according to claim 35, wherein said flow inducing
means is formed by or includes said separation means, and said
separation means is located between said storage means and said
mixing chamber.
37. Apparatus according to claim 35 or 36, wherein said storage
means includes a plurality of compartments, one of which is a
storage compartment for said body of fibres, and each said
compartment has an exit port that can be selectively opened or
closed.
38. Apparatus according to claim 37, wherein another of said
compartments is a storage compartment for a body of particles of
resilient material, and said flow inducing means is operative to
cause particles to exit said particle storage compartment when the
exit port of that compartment is open.
39. Apparatus according to claim 38, including metering means
operative to control the ratio of said fibres and said particles
when said fibres and said particles are being simultaneously
extracted from their respective said compartments.
40. Apparatus according to claim 39, wherein said metering means is
adjustable to vary said ratio.
41. Apparatus according to claim 34 including a feed auger being
operable to supply said fibres and particles to the separation
means, the feed auger being rotatable about an axis, the speed of
rotation being adjustable to adjust the rate of supply of fibres
and particles to the separation means.
42. Apparatus according to claim 40 including storage means for
containing a body of said fibres or said particles and agitation
means for agitating said fibres or said particles to move towards
the feed auger.
43. Apparatus according to claim 40 or 41 including flow inducing
means for inducing fibres or particles to exit the separation
means.
44. Apparatus according to claim 42, wherein the flow inducing
means is an impeller located between the separation means and
mixing chamber.
45. Apparatus according to any one of claims 34 to 44, wherein said
mixing chamber is movable across said body of soil.
46. Apparatus according to claim 45, wherein said mixing chamber
forms part of an assembly including the following components said
soil engaging means, said storage means, said flow inducing means,
said separation means, and said metering means.
47. Apparatus according to claim 46, including prime moving means
for moving the assembly relative to the body of soil.
48. Apparatus according to claim 47, wherein the prime moving means
is separable from the assembly.
49. Apparatus according to claim 48, wherein the prime moving means
provides drive means for the operation of the components of the
assembly.
50. Apparatus for processing bulk foamed material to produce
particles of predetermined size including: a slicing means
including a plurality of slicing discs being operable to process
the bulk material into strips; a mulching means including a
plurality of mulching discs being operable to process the sliced
material into particles of predetermined size; and a sieve defining
at least in part a mulching zone within which the mulching discs
operate, the sieve permitting material of a predetermined size to
pass therethrough.
51. Apparatus according to claim 50, wherein the slicer discs are
located on opposing shafts, the shafts being rotatable in opposite
directions.
52. Apparatus according to claim 51, wherein the speed of rotation
of each shaft is adjustable so as to adjust a speed at which sliced
material is discharged from the slicing means.
53. Apparatus according to claim 51 or 52, wherein each slicing
disc on each shaft is separated by a boss of substantially similar
thickness, the opposing shafts being positioned such that the
slicing discs on opposing shafts interleave and overlap.
54. Apparatus according to any one of the preceding claims, wherein
each mulching disc on each shaft is separated by a boss of
substantially similar thickness to the mulching disc, the opposing
shafts being positioned such that each mulching disc on opposing
shaft interleaves.
55. Apparatus according to any one of the preceding claims, wherein
each mulching disc includes a tooth which is negatively raked to
facilitate mulching of the stripped material and movement of the
material from a lower position within the mulching zone to an upper
position in the mulching zone.
56. Apparatus according to claim 54, wherein the speed of rotation
of one shaft is approximately one half to one third speed of
rotation of the other shaft.
Description
[0001] This invention relates to the load bearing qualities of soil
and soil based materials, including the behaviour of soil and soil
based materials when subjected to impact loading. The invention is
particularly concerned with providing a soil based material having
improved load bearing qualities, and is also concerned with the
method of producing such a material.
[0002] In the context of this specification a "soil based material"
is to be understood as a material including soil and at least one
additive mixed with the soil. Such a material may or may not
provide a growing medium for grass and/or other forms of plants. It
is to be also understood that the term "soil" includes sand as well
as sand composites such as a mixture of sand and clay, or a mixture
of sand and organics, by way of example.
[0003] It is known to attempt to improve the strength of soil by
providing a mixture of soil and a fibrous or other strengthening
component. One such proposal is the subject of Australian patent
586766. Other prior proposals are briefly described at pages 2 and
3 of the specification of AU 586766.
[0004] Prior proposals of the foregoing kind have not been
successful for a variety of reasons. One common problem is
compaction of the surface during use, and as a consequence the
surface no longer satisfies the required performance standards.
Another common problem is inadequate drainage, which also leads to
a reduction in performance.
[0005] It is an object of the present invention to provide a soil
based material that at least alleviates the aforementioned
problems. It is yet another object of the invention to provide a
soil based material having a composition that can be varied to suit
a particular use of the material, or a particular circumstance of
use of the material. Still another object of the invention is to
provide a method of producing a material of the foregoing kind. Yet
another object of the invention is to provide a method of
maintaining the surface of material of the foregoing kind so as to
maximise the performance of that surface when in use. An object of
the invention in a preferred form is to provide a soil based
material that promotes growth of grass or other vegetation by
retention of nutrients and other fertilisers, air and water, whilst
at the same time promoting good drainage of excess water.
[0006] A soil based material according to the present invention is
characterised in that it is composed of or includes a soil matrix
and fibres scattered throughout that matrix. The fibres may be
synthetic fibres (eg., fibreglass), or naturally occurring fibres
such as animal, plant, or vegetable fibres, or a mixture of
synthetic fibres and naturally occurring fibres. In the case of
synthetic fibres, they may be mono fibres or fibrillated fibres, or
a mixture of mono and fibrillated fibres.
[0007] Biodegradable fibres such as plant or vegetable fibres may
be used in circumstances where the fibres are required to have a
temporary influence. By way of example, they may be required to
function as a binding agent until development of a substitute, such
as the root structure of grass grown on the soil based material. A
mixture of flax fibre and synthetic fibre has been found useful in
some applications, and the synthetic fibre content may be minor by
comparison with the flax fibre content.
[0008] In the context of this specification a mono-fibre is a
single filament or single strand fibre. A fibrillated fibre on the
other hand is supplied in flat ribbon-like form that splits and
tends to expand into an open mesh-like structure when stretched
laterally. That is, the flat ribbon includes a number of
interconnected strands arranged so that when the fibre is stretched
laterally the strands form an open mesh structure similar to that
of expanded metal.
[0009] The fibres can be of any length and cross-sectional size to
suit particular circumstances of use. By way of example, in one
application of the present invention mono-fibres approximately 38
mm long and having a cross-sectional size equivalent to 8 denier or
thereabouts have been used successfully. In another application, 8
denier mono-fibres approximately 19 mm in length have been used
successfully. Longer fibres (eg., 38 mm) are usually preferred if
grass is not grown on the soil based material. Shorter fibres (eg.,
19 mm) are usually preferred if grass is grown on the soil based
material, in this regard fibres having a length in the range of
between 15 mm to 20 mm inclusive are particularly preferred. The
length and/or cross-sectional size may vary however, to suit
different applications and/or different circumstances of use of the
material. Fibres having a length of 50 mm, or greater, could be
employed. Fibrillated fibres in the size range 700 to 1000 denier
have been successfully employed, but fibres outside of that size
range may be satisfactory. Once again different applications and/or
different circumstances of use can be a determining factor.
[0010] The stability of a fibre is an exponential function of its
length. By way of example, if the length of one fibre is half that
of another fibre, the stability of the first mentioned fibre may be
as little as one tenth, or even one hundredth, the stability of the
second mentioned fibre.
[0011] The fibres are preferably dispersed substantially evenly
throughout the soil matrix. It is also preferred that the fibres
are separated to an extent such that there is minimal tendency for
them to congregate and form discrete clumps or bunches that are
scattered in spaced relationship throughout the matrix. One method
of avoiding or minimising bunching of the fibres includes inducing
an electrostatic charge into the fibres so that they have a natural
tendency to separate as they are fed through a blower/impeller
system towards a storage zone or the soil matrix. Other techniques
could be adopted to achieve the same result.
[0012] The soil matrix preferably includes an additive or additives
other than the fibres. By way of example, the soil matrix may have
an organic material such as sawdust, wood chips, bark pulp, or
potting mix (to name a few examples only), dispersed throughout.
Such a mixture may be adopted whether or not the soil based
material is intended to provide a growing medium for grass, for
example. In either case, the purpose is to retain moisture within
the soil based material. If the material provides a growing medium
for grass (for example) the moisture assists in growing the grass.
If the material does not provide a growing medium for grass (for
example) the moisture assists in bonding the sand granules or other
soil particles.
[0013] For some applications of the soil based material, that
material may also include an additive in the form of particles of a
resilient material (eg., foamed polyethylene) scattered throughout
the soil matrix. It is preferred that there is a substantially
regular dispersion of the particles throughout the matrix. Such an
additive is beneficial in circumstances where the soil based
material is to be used as the surface, or as a surface layer, of an
area that will be subjected to scattered impact loads. By way of
example, such impact loading is encountered in sports fields and
sports tracks, and is also encountered in farm tracks, animal
holding yards, calving paddocks and animal drinking or feeding
areas. It is usually preferred that the material of which the
resilient particles are formed is selected so as to have a high
rate of recovery when distorted, and a low propensity to
collapse.
[0014] It will be convenient to hereinafter describe the invention
in greater detail by reference to one example application of the
soil based material. It is to be understood however, that the soil
based material has other applications, and that the composition of
the material may vary according to its intended application.
[0015] FIG. 1 is a preferred example embodiment of the soil based
material in diagrammatic form.
[0016] FIG. 2 is a preferred embodiment of a multi-stage blower
system in diagrammatic form.
[0017] FIG. 3 illustrates a preferred example embodiment of a
mixing machine in diagrammatic form.
[0018] FIG. 4 is an example preferred embodiment of the surface of
the roller in diagrammatic form.
[0019] FIG. 5 illustrates in diagrammatic form one preferred
embodiment of mulching apparatus for producing particles.
[0020] FIG. 6 is a preferred embodiment of a blade from the
apparatus shown in FIG. 5.
[0021] FIG. 7 is a cross-section in diagrammatic form of the
apparatus from FIG. 5.
[0022] FIG. 8 is a detailed view of the sieve from FIG. 7.
[0023] FIGS. 9 and 10 are preferred embodiments of the sieve in
plan from FIG. 7.
[0024] FIG. 11 illustrates in diagrammatic form one possible
arrangement of a drainage system for use with the soil based
material illustrated in FIG. 1.
[0025] FIG. 12 illustrates in diagrammatic form a preferred tread
pattern.
[0026] FIG. 13 illustrates in diagrammatic form a multi-series
arrangement for tread patterns illustrated in FIG. 12.
[0027] FIG. 14 illustrates a preferred embodiment of the apparatus
for laying the soil based material.
[0028] FIG. 15 illustrates a manifold separating the separation
means from the mixing chamber.
[0029] FIG. 16 illustrates in diagrammatic form a preferred
embodiment of a height adjusting means.
[0030] FIG. 17 illustrates a preferred embodiment of the storage
means.
[0031] FIG. 18 illustrates a preferred embodiment of soil mixing
discs.
[0032] FIG. 19 illustrates an alternate preferred embodiment of the
apparatus for laying the soil based material.
[0033] FIG. 20 illustrates in diagrammatic form a preferred
embodiment of the feed auger and separation means.
[0034] FIG. 21 is an isometric view in diagrammatic form of an
alternate form of apparatus for producing particles.
[0035] FIG. 22 is a cross sectional view of the alternate form of
apparatus for producing particles from FIG. 21.
[0036] One example use of the soil based material is in forming the
running surface of a track used for horse races or similar events.
The example embodiment of the invention hereinafter described in
detail is only one of several embodiments that may be used for that
purpose.
[0037] The running surface of a race track incorporating an
embodiment of the invention may be composed of two or more layers.
In the example shown in FIG. 1 of the drawings there are three
layers--a surface layer 1, an intermediate layer 2, and a base
layer 3. Each layer may have a thickness selected to suit the
particular circumstances of use, but in one example that has
performed well in practice each layer is approximately 50 mm
thick.
[0038] The upper layer 1 includes a soil matrix 4 and a
substantially regular dispersion of fibres 5 within that matrix. If
the layer 1 is intended to provide a growing medium for grass (for
example), the soil based material may also include organic material
as hereinbefore described distributed substantially regularly
throughout the matrix. The amount of organic material used can be
selected to suit particular applications and circumstances of use.
In the example hereinafter described it is preferred that one cubic
metre of the soil (eg., sand) and organic material composite
includes approximately 0.04 cubic metres of the organic
material.
[0039] It is also preferred that, in at least some embodiments of
the invention, a wetting agent is applied to the sand so as to
promote retention of moisture within the soil matrix. If desired, a
tackifying agent may be included with the wetting agent so that a
moisture retaining crust is provided over the sand granules.
[0040] Any suitable method may be employed in producing the surface
layer 1. Preferably that layer includes organic material as
previously described, and a substantially homogeneous mixture of
the soil matrix 4 and the organic material is preferably produced
before adding the fibres 5. It is further preferred that the fibres
5 are deposited onto a surface of that homogeneous mix, after which
an appropriate mixing process is adopted to achieve a substantially
regular distribution of the fibres 5 throughout the soil matrix 4.
The fibres 5 may be in a moist or dry state as they are being
deposited onto the surface of the soil matrix 4. Regardless of the
state of the fibres 5 however, the surface of the matrix 4 may be
moist to promote retention of the fibres 5 on that surface.
[0041] It is preferred that the fibres 5 are subjected to a
separation treatment prior to being mixed with the soil matrix 4.
The purpose of such treatment is to avoid or minimise bunching of
the fibres 5 such as to lead to the presence of discrete relatively
dense separated groups of fibres 5 within the soil matrix 4.
[0042] The separation treatment may include passing the fibres 5
through a blower/impeller system which is arranged to encourage
separation of individual fibres. An example system of that kind is
illustrated in diagrammatic form by FIG. 2 of the drawings
accompanying this specification.
[0043] FIG. 2 illustrates a multi-stage system involving use of at
least two blowers--a first stage blower 7 and a final stage blower
8. It is preferred, as shown, that at least one intermediate stage
blower 9 is positioned between the first and final stage blowers 7
and 8. FIG. 2 shows three intermediate stage blowers 9, but the
number could be less or greater according to requirements. As
shown, it is also preferred that the final stage blower 8 is of
larger capacity than each of the preceding blowers 7 and 9. Each of
the blowers 7 and 9 may be of substantially the same capacity, but
that is not essential.
[0044] Relatively small blowers 7 and 9 are preferably used in the
initial stages so that a relatively small volume of fibres 5 is
treated during passage through each of those blowers 7 and 9. That
is intended to enable maximum separation of individual fibres. A
larger final stage blower 8 is considered desirable to maintain,
and possibly improve, the separation achieved within the preceding
blowers 7 and 9. In the arrangement shown, the final stage blower 8
directs the separated fibres 5 into a storage compartment 10. It is
possible however, to adopt a different system in which the fibres 5
are moved directly from the blower 8 for deposition on, or mixing
with, the soil matrix 4.
[0045] It is preferred that the separation treatment is arranged in
a manner such that the fibres 5 become electrostatically charged
during that treatment. By way of example, in the FIG. 2
arrangement, such a charge may be induced during passage of the
fibres through the blowers 7, 9 and 8, and/or during passage
through ducts interconnecting those blowers. In addition, or in the
alternative, the chamber 10 may have ribs or other projections 11
or surfaces over which the fibres 5 move so that an electrostatic
charge is induced through frictional engagement. It will be
appreciated that other techniques could be employed to achieve the
desired result.
[0046] The purpose of the electrostatic charge is to assist the
separation process. The combined influence of the electrostatic
charge and the blower induced movement of the fibres 5 encourages
lateral separation of the fibres 5, and also encourages the fibres
5 to move longitudinally through the system. That is, the
longitudinal axis of each fibre 5 extends generally in the
direction of movement of the fibres 5.
[0047] It has been found that relatively fine fibres (eg., 8 denier
or more) tend to retain a relatively high electrostatic charge. On
the other hand, finer fibres of less than 8 denier can be
satisfactorily employed.
[0048] Fibres 5 may be extracted from the chamber 10 and delivered
to the surface of the soil matrix 4 through a delivery duct system
12. A duct system 12 of substantial length may assist in enabling
convenient handling of material. By way of example, ducting 40 to
50 metres in length has been used successfully. Alternative to
delivering the fibres 5 direct to the soil matrix 4, the system 12
may deliver the fibres 5 to individual storage containers (not
shown) or to a compartment of a spreading device (not shown). In
any event, the system 12 may be arranged to maintain or reinforce
the electrostatically charged state of the fibres 5.
[0049] The fibres 5 could be a mixture of different fibres. By way
of example, a substantially 50/50 mixture of mono-fibres and
fibrillated fibres has been found to be particularly satisfactory
in some applications. The mono-fibres provide a hair-like structure
and function as a binding agent within the soil matrix. The
fibrillated fibres on the other hand introduce another quality into
the mix such that the soil matrix is able to move under load and
absorb shock. That arises out of the fact that a fibrillated fibre
can change its dimensions under impact. Such a fibre will respond
to impact by widening in a lateral direction and reducing in
length. When the load is removed, the fibre will tend to return to
its initial width and length. It is generally preferred to produce
a substantially homogenous mix of the mono-fibres and the
fibrillated fibres prior to introducing the fibres to the soil
matrix 4. It is also preferred to mix the fibres prior to
subjecting the fibres to the separation treatment described
above.
[0050] In one application, it has been found that satisfactory
results can be obtained with a soil/fibre mix including 1 to 6
kilograms (preferably 2.6 kilograms) of a 50/50 mix of mono and
fibrillated fibres in each cubic metre of the soil matrix 4. By way
of comparison, if mono-fibres alone are used for the same or
similar application, a fibre content of approximately 17 kilograms
per cubic metre of soil matrix may be required.
[0051] Various techniques can be adopted for depositing the fibres
5 and mixing the fibres 5 with the soil matrix 4. By way of
example, the fibres 5 may be deposited manually or by a machine
aided process. In either case however, it is preferred that
appropriate measures are taken to ensure that the quantity of
fibres 5 deposited per unit area of the soil matrix surface is
substantially consistent. By way of example, the soil matrix
surface may be divided into a number of sections of a substantially
equal size by way of a grid pattern, and a measured quantity of
fibre 5 may be deposited on each of those sections.
[0052] In an alternative arrangement, a spreading device may be
moved over the surface of the soil matrix 4 at a predetermined
speed, and operated to deposit fibres onto that surface at a
predetermined rate of deposition. The speed of travel of the
spreading device may be related to the rate of fibre deposition so
as to achieve the desired spread of fibres 5 per unit area of the,
surface. Other techniques could be adopted to achieve the same
result.
[0053] The deposited fibres 5 can be mixed with the soil matrix 4
by any suitable process, including manual or machine aided
processes. In one example method a rotary disc hoe or similar
machine, is employed to mix the fibres 5 into the soil matrix
4.
[0054] FIG. 3 illustrates in diagrammatic form an example mixing
machine 13 which may be tractor drawn or otherwise moved across the
fibre coated surface 14 of the soil matrix 4. The machine 13 may
include a series of rotatable discs 15, or other suitable blades,
the rotational axis of which extends transversely, or angularly,
relative to the direction of travel of the machine 13. The discs 15
are arranged to penetrate into the soil matrix 4 and are rotated as
the machine 13 moves over the surface 14. In the example
arrangement shown, the direction of rotation of the discs 15 is
such that they lift the fibres 5, generally with some of the soil,
and deposit those fibres 5 (and soil) rearwardly of the series of
discs 15 into a furrow or depression 16 created by the rotating
discs 15.
[0055] It is preferred that a freely rotatable roller 17 is drawn
behind the machine 13 and is arranged to restore the surface 14 to
a substantially flat and level condition. Any suitable roller 17
may be used for that purpose, including a roller having a smooth
cylindrical surface. According to one example, the cylindrical
surface of the roller 17 is formed by a series of intersecting bars
or ribs 18 arranged to form an open-mesh structure as illustrated
diagrammatically in FIG. 4. The ribs 18 may extend around a shield
or solid internal structure of the roller 17 so that soil cannot
pass through the mesh openings 19 to the interior of the roller
17.
[0056] Thorough mixing of the fibres 5 and soil matrix 4 may be
achieved in a single pass of the machine 13. In some applications
however, a greater number of passes (eg., 10 or more) may be
required.
[0057] The intermediate layer 2 preferably includes a soil matrix 4
and dispersed fibres 5 as described above in relation to the
surface layer 1. It also preferably includes resilient particles 20
distributed throughout the soil matrix 4 in a substantially regular
manner. The resilient particles 20 may also be located in the upper
layer 1 however this is not essential. The resilient particles 20
are preferably added to the soil matrix 4 prior to or simultaneous
with addition of the fibres 5, and any suitable method may be
employed to achieve a substantially regular distribution of the
particles 20 throughout the mix. By way of example, the particles
may be mixed into the soil matrix 4 by a technique the same as or
similar to the technique used to mix the fibre with the soil.
[0058] The particles 20 may be formed of foamed polyethylene (open
or closed cell) or any other suitable material. According to one
method, the particles are created by passing a sheet or block of
the selected resilient material through a hammer mill or other
impact device operable to reduce the sheet into separated particle
form. Alternative to impact shredding of the resilient material,
sheets or blocks of the selected material may be divided into
separated particle form by a cutting operation. By way of example,
a hammermill-type of device having cutting blades instead of impact
hammers may be employed. Cutting as distinct from impact shredding
has the benefit of minimising the extent of which the particles
have less elasticity than that of the sheet or block from which
they are formed. Other techniques could be used, but it is
preferred that the selected technique produces relatively small
rough surfaced particles. In the case of sheet material, it is
preferred to use sheets of approximately 3mm thickness if impact
shredding is employed. Thicker sheets or blocks of material can be
used if a cutting technique is employed.
[0059] FIG. 5 illustrates, in diagrammatic form, one type of
apparatus for producing the particles 20. In that example apparatus
a series of discs 21 are mounted on a rotatable drive shaft 22 so
as to rotate with that shaft. As shown, the discs 21 are arranged
in axially spaced relationship. The number of discs 21, and their
axial spacing, may be selected to suit requirements. A group of
cutter blades 23 is provided between each two adjacent discs 21,
and in the arrangement shown each blade 23 in each group is
rotatably mounted on a respective pivot shaft 24. Alternatively,
the pivot shafts 24 could be omitted and each blade 23 could be
pivotally connected to an appropriate one of the discs 21 in any
suitable manner. In the particular arrangement shown, each blade 23
is located between two spacer tubes 25 mounted on the respective
pivot shaft 24. The tubes 25 function to hold the blade 23 against
movement in the axial direction of the shaft 24. Other arrangements
could be adopted for that purpose.
[0060] The angular or rotational disposition of each blade 23 as
shown by FIG. 5 is not necessarily the position adopted when the
discs 21 are at rest. The blade dispositions as shown by FIG. 5
have been adopted for convenience of illustration.
[0061] Each pivot shaft 24 is located radially outwards from the
rotational axis of the drive shaft 22, and may extend through each
of the discs 21 as shown by FIG. 5. It is preferred that the pivot
shafts 24 are arranged in substantially equally spaced relationship
around an imaginary circle that is substantially coaxial with the
drive shaft 22. The number of pivot shafts 24 can be selected to
suit requirements, but six such shafts have been successfully
employed in one application of the invention.
[0062] In the particular arrangement shown by FIG. 5, each cutter
blade 23 is similar to the blades used in grass mowers, but other
types of blades 23 could be used. Each blade 23 has one end
rotatably mounted on a respective one of the pivot shafts 24, and
has one or more cutting edges 26 at the other (outer) end. An outer
corner portion of the blade 23 may be upturned as shown by FIG. 6.
A cutting edge 26 may be provided along each exposed edge of that
upturned portion 27, and further cutting edges 26 may be provided
along the extreme outer edge of the blade 23, and also along an
outer portion of the blade side edge 28. Other arrangements could
be adopted to suit requirements.
[0063] In the arrangement shown, sheets or blocks 29 (FIG. 7) of
polyethylene (for example) are fed into the apparatus so as to
enter a treatment zone 30 formed between the discs 21 and a screen
31. The depth of the treatment zone can be selected to suit
requirements. In one application of the invention the depth of the
zone 30 is selected so that the distance "D" between the tip of a
blade 23 and the screen 31 (see FIG. 8) is in the range 2.5 to 3
mm. A sheet or block 29 located within or approaching the zone 30
is exposed to impact by the blades 23 and is thereby reduced to
particles 20, which pass through openings 32 in the screen 31.
[0064] In the arrangement shown by FIGS. 5 and 7, the screen 31
functions as a sieve, and also functions as a boundary of the zone
30. Other arrangements could be adopted. By way of example, the
screen 31 may be located remote from the zone 30, and another
member could provide the boundary of the zone 30.
[0065] The apparatus as shown diagrammatically by FIG. 7 includes a
cylindrical hollow housing 33, part of which is formed by the
screen 31. The sheets or blocks 29 enter the housing 33 through an
inlet opening 34, and are reduced into particle size as described
above. As shown, the discs 21 rotate in the direction in which the
sheets or blocks 29 move through the zone 30, and that may result
in the sheets or blocks 29 being drawn too quickly through the zone
30. In order to counter that effect the speed of movement of the
sheets or blocks 29 into the zone 30 may be controlled by
appropriate feed means. In other arrangements, the discs 21 may
rotate counter to the direction of movement of the sheets or blocks
29, in which event some other form of feed means may be required.
Also, alternative to what is shown by FIG. 7, the housing 33 may be
provided with an exit opening for passage of residue unable to pass
through the screen 31.
[0066] It is preferred that the particles 20 are of relatively
small size, but neither the size nor the shape of the particles
needs to be regular or consistent. Avoidance of overly large
particles 20 may be achieved by use of a separating sieve, such as
the screen 31, or similar device. That is, in the example shown by
FIG. 5, particles that pass through the screen 31 are acceptable,
whereas particles that do not pass through the screen 31 are not
acceptable. The non-acceptable particles may be subjected to
further processing in order to reduce them to an acceptable
size.
[0067] FIG. 9 shows, in diagrammatic form, one type of sieve
opening 32 that may be used in the screen 31, for example. In the
example shown the shape of each opening 32 is substantially
hexagonal, but other shapes could be adopted. Satisfactory results
have been achieved with openings 32 in which the distance between
opposite flat sides 36 of the opening 32 is approximately 16 mm,
and the distance opposite corners is approximately 21 mm. Other
dimensions could be used, and the distance need not be the same for
each of the three pair of sides 36, or for each of the three pair
of corners.
[0068] The openings 32 are preferably formed in a manner such that
the edges of each opening 32 are jagged or rough. It has been found
that jagged or rough edged openings 32 assist in producing
particles 20 having rough, surfaces, which as previously stated is
a desirable characteristic of the particles 20. The rough surfaces
of the particles 20 assists retention of the particles 20 within
the soil matrix, and also assists formation of a connection between
the particles 20 and the root structure of grass and/or other
vegetation. The jagged or rough edges of the openings 32 tend to
catch the polyethylene sheet or block 29 and thereby promote
tearing of the sheet or block 29 such that the desired rough
surfaces are produced on the particles 20.
[0069] The openings 32 may be produced by a punching operation so
that each opening 32 has rough or jagged side edges. Other
techniques could be used to produce the same result. Assuming use
of a punching operation, the plate or sheet used to form the screen
31 may be initially provided with a series of regularly spaced and
relatively small holes 37 as shown by FIG. 10. Each opening 32 is
subsequently produced by punching out a substantially hexagonal
section of material 38 having a hole 37 at each of its corners, as
also shown by FIG. 10. The punching operation tends to produce a
jagged edge along each side 33 of the opening 32, and also tends to
produce a jagged edge 39 (FIG. 9) at the junction of each side 36
and the remnants of a hole 37. It will be appreciated that
satisfactory results could be achieved with openings 32 of other
shapes produced by the same or different method. It is generally
prepared however, that the openings 32 are of irregular shape.
[0070] An alternate form of apparatus for producing particles 20 is
illustrated in FIG. 21. The apparatus illustrated includes a
slicing means 240 and a mulching means 241 located adjacent the
slicing means 240. Bulk foamed material normally in sheets or
blocks is fed to the slicing means 240 which is operable to slice
the bulk material into strips. The stripped material is fed to the
mulching means 241 to mulch the stripped material into particles of
predetermined size. The particles are deposited into conduit system
242 and moved there along by an impeller (not shown) to a storage
hopper (not shown).
[0071] Referring still to FIG. 21 the slicer means 240 illustrated
includes a plurality of slicing discs 245 each separated by a boss
243 (see FIG. 21) on opposing shafts 244. The discs 245 interleaf
and overlap, which is best illustrated in FIG. 22. Whilst the
degree of overlap of the discs 245 shown in FIG. 22 extends to the
boss 243, a lesser overlap may also be suitable.
[0072] FIG. 22 illustrates the discs 245 located in a slicing zone
246. A plurality of fingers 247 extends between the discs 245 to
facilitate separation of the sliced material from the slicing discs
245. The discs 245 preferably rotate in opposite directions at
substantially the same speed. In this regard speeds of
approximately 120 to 160 rpm have been found suitable.
[0073] Referring still to FIG. 22 the sliced material is supplied
to the mulching zone 248 and more specifically presented to a pair
of counter rotating mulching discs 249. Each mulching disc includes
a negatively raked tooth to facilitate mulching the sliced material
and also facilitating raising material from a lower position in the
mulching zone to an upper positing in the mulching zone 248. Each
mulching disc is separated by a boss (not shown) to allow the
mulching discs to interleave. The mulching zone is defined by an
external perimeter in the form of a sieve which permits mulched
material to pass through the sieve once it has been mulched to a
predetermined size.
[0074] FIG. 22 illustrates a mulching means having a primary
mulching zone 248 and a secondary mulching zone 250. The two
mulching zones are substantially identical with the exception being
the nominal diameter of the sieve size of the primary mulching zone
is larger than the nominal sieve size for the secondary mulching
zone 250. It should be appreciated that a primary and secondary
mulching zone is merely preferred and that the invention may be
satisfied by a single mulching zone.
[0075] The counter rotating mulching discs preferably rotate at
differing speeds. More specifically it is preferred that one
mulching disc rotate at a half to a third of the speed of rotation
of the opposing mulching disc. In this regard speeds of 240 rpm to
80 rpm have been found most preferred.
[0076] In one example application of the invention it has been
found satisfactory to produce particles 20 from a 3 mm thick sheet
29, and which particles have an approximate length of 25 mm and an
approximate width of 20 mm. Such particles 20 have been produced
using the apparatus of FIG. 5, and using a screen having openings
32 as described in relation to FIGS. 9 and 10. In such cases the
reduction process used to produce the particles 20 also tends to
produce smaller particles, including fines, and those smaller
particles and fines can be usefully employed in this or other
applications of the invention.
[0077] The dimensions referred to in the preceding paragraph have
been found satisfactory in circumstances where the resilient
particles 20 are to be used in a surface layer, or a sub-surface
layer, of a race track or the like. Other dimensions and/or sieve
opening shapes could be employed to suit other applications of the
particles, and other circumstances of use. By way of example,
relatively small particles, down to fines, could be used in some
applications. In addition, for some applications and/or
circumstances of use there may be a benefit in using a mixture of
particles of different sizes. That is, there may be a mixture of
relatively large and relatively small particles, the ratio of which
could be selected to control the amount of rebound energy of the
material containing those particles.
[0078] The intermediate layer 2 may also include the other
additives as used in upper layer 1 such as organic material,
wetting agents, fertilisers and the like.
[0079] The base layer 3 may be essentially a layer of soil.
Preferably, the layer 3 is composed of sand or a sand composite
that functions to regulate drainage of water away from the
overlying intermediate layer 2. Ideally, the drainage
characteristics of the base layer 3 are such that excessive
saturation of the overlying layers 1 and 2 is avoided, whilst at
the same time ensuring retention of a suitable level of moisture in
those layers.
[0080] The multi-layered group 1, 2 and 3, may overlay a base of
clay or other suitable material. In some applications, the surface
layer 1 may be omitted, and in other applications the intermediate
layer 2 may be omitted whilst the surface layer 1 is retained.
[0081] As indicated above, the base for the multi-layer to Group 1,
2 and 3, or a variation thereof, may be formed of clay. Other
impervious or semi-pervious materials could be used instead of
clay. Also, in some circumstances (eg., areas of high rainfall) the
base material may be selected so as to have a degree of porosity
such as to enable sufficiently rapid dispersal of moisture through
the base. Use of such permeable material may not be required if
there is provision for collecting and re-using moisture that
reaches the base.
[0082] In circumstances where a clay or other impervious, or
semi-impervious, base is used, appropriate steps may be taken to
ensure drainage of excess water from that base. That may be
achieved by providing drainage tubes or channels within the clay
base, and well known techniques can be used for that purpose. Also,
a layer of screenings may be provided over the top of the clay base
so as to intervene between that base and the surface layer or
layers overlying the base. By way of example, the screenings may be
approximately 7 mm in size, and the screening layer may be
approximately 70 mm thick. Other dimensions could be selected to
suit particular applications and particular circumstances of
use.
[0083] FIG. 11 illustrates, in diagrammatic form, one possible
arrangement of a drainage system for use with a clay or other
impervious base 40. The system includes use of pipes or tubes 41 of
a well known kind having apertures or slots 42 to permit passage of
water through the wall of the tube 41. A layer of screenings 43 is
provided above, at each side, and below of each tube 41. In a
preferred arrangement the body of screenings 43 is at least
substantially composed of stones, pebbles, or the like, having a
smooth or rounded surface. Screenings, of that kind have the
benefit of leaving gaps within the body of screenings 40 that
permit passage of water. Jagged or rough edged screenings are more
likely to fit together in such a way as to trap material having the
tendency to block passage of water. A layer of screenings 44 may be
provided over the top of the base 40, and that layer also may be at
least substantially composed of screenings as described above.
[0084] Each tube 41 may be a circular tube approximately 100 mm in
diameter, but other shapes and dimensions could be adopted. The
depth of the screenings layer 43 beside, above and below the tube
41 may be approximately 100 mm in each case, and again other
dimensions could be adopted. The screenings layer 44 may be
approximately 70 mm thick as previously indicated.
[0085] Water drained from the clay or other base may be collected
in a suitable holding facility (eg., tank or dam) for re-use as
required. The same conservation technique may be used in respect of
surface run-off and excess water drained from other regions of an
installation employing a surface layer or layers according to the
invention.
[0086] The soil based material described above can be produced
off-site, or on-site, according to requirements. In the former
case, any appropriate method may be used to transport the material
to the relevant site and to deposit the mix at that site.
[0087] The fibres 5 in the surface layer 1 have several benefits.
The fibres 5 strengthen the layer and thereby reduce deterioration
due to impact and other loading. The fibres 5 also improve the
sustainability of the grass by minimising root shear and promoting
regeneration of the grass after damage however caused.
[0088] When used in the intermediate layer 2, the fibres 5
strengthen the layer 2 and also have a stabilising influence on the
resilient particles 20 such that migration of those particles
within the soil matrix 4 is prevented or minimised. Eventual
penetration of grass roots into the layer 2 has a similar
stabilising influence.
[0089] The resilient particles 20 in the intermediate layer 2 have
the benefit of providing the surface layer 1 with a "bounce-back"
or cushioning characteristic. A horse, for example, running on the
surface layer 1 is therefore likely to suffer minimal stress due to
impact with the surface layer 1. In addition, the cushioning
characteristic enables the surface layer 1 to reform after impact
so as to remove or reduce indentations formed in that layer by
impact or other loading. That is, expansion and contraction of the
particles 20 inhibits, or prevents, compaction of the soil.
[0090] Yet another benefit of the resilient particles 20 is their
ability to function as a sponge for retention of fertilisers and
other nutrients, for, example. In addition, grass roots tend to
bond with the particles 20 thereby promoting maintenance of the
grass carpet formed over the surface layer 1.
[0091] It will be appreciated from the foregoing that a soil based
material according to the invention has important benefits when
used in any of a variety of applications. Each of the soil based
layers 1 and 2 hereinbefore described is an individual example of
the soil based material according to the invention, and each can be
used independently of the other in appropriate circumstances. As
previously stated however, a soil based material according to the
invention may have a composition different to that described in
relation to either the surface layer 1 or the intermediate layer 2
described above.
[0092] Soil based material according to the invention has numerous
applications. A soil based material as described above in relation
to the surface layer 1 has a high degree of stability and can be
beneficially used in locations, such as paddock gateways, that are
subjected to a relatively high incidence of traffic and/or high
loading. Other agricultural uses include farm tracks, animal
holding yards, calving paddocks and animal drinking and feeding
areas, for example. The soil based material could be used to
stabilize road and other carriageway surfaces, and could be
usefully applied around watering facilities such as dams and
troughs that are subjected to heavy use. Other applications are
clearly available. The foregoing applies whether or not the soil
based material provides a growing medium for grass, or other
vegetation.
[0093] The above comments also apply to the soil based material
described of in relation to the intermediate layer 2. That mix
however, has particular benefit in circumstances requiring a
surface that is substantially self-restoring in that depressions
caused by scattered impact loading tend to reduce, or substantially
disappear, due to the natural resilience or "bounce-back" quality
of the mix.
[0094] A three layer arrangement as described above in relation to
FIG. 1 of the drawings is particularly useful when used as the
running surface of a horse racing track, for example.
[0095] The soil/fibre mix (eg., layer 1 as previously described)
without grass can be used to form the surface of a track subjected
to impact or compressive loads. In such circumstances,
deterioration of the track surface can be prevented or minimised by
applying an embossed pattern to that surface.
[0096] By way of example, the embossed pattern may be a
"herringbone" pattern or a chevron pattern, involving a series of
alternating ridges and valleys. Such a pattern could be created by
use of a suitably formed roller for example, or a series of tyres
having a suitable tread pattern. It is preferred that the ridges
and valleys extend at an angle relative to the longitudinal edge of
the track. It is further preferred that the angle is an angle other
than 90.degree. so as to minimise the speed or rate of water
run-off towards the edge of the track.
[0097] Such a surface pattern can function to minimise run-off of
surface water and thereby promote maintenance of a suitably moist
track, and could be applied to the entire surface of a track or to
portions only of the track. The pattern also minimises wind induced
erosion of the track surface. Soil blown from the top of the ridges
tends to collect and be retained within the valleys. The surface
pattern can be restored to its maximum effectiveness by occasional
re-application of the patterned roller, for example. The frequency
of such maintenance treatment may of course vary according to
circumstances.
[0098] FIG. 12 illustrates, in diagrammatic form, one particular
method of producing the embossed pattern referred to above. In the
example shown, a series of closely packed wheels 45 is arranged for
rotation about an axis 46. Each wheel 45 has a rubber tyre 47
having treads 48 arranged substantially as shown by FIG. 12. A
feature of the treads 48 as shown is their angular disposition and
the presence of an overlap at their inner ends 49. It will be
appreciated that other tread arrangements could be employed. The
tyres 47 are preferably inflated to a relatively high pressure, and
may be connected to a carriage (not shown) that has a weight such
as to ensure that the tyre treads 48 penetrate into the surface of
the soil layer to create the embossed pattern.
[0099] The number of wheels 45 within the series can be selected to
suit requirements. Also, two or more series of wheels 45 could be
arranged in tandem, and an example of such an arrangement is
illustrated by FIG. 13.
[0100] In the example arrangement, shown by FIG. 12, the tyres 47
are approximately 660 mm wide, and each tread 48 produces a furrow
or channel in the soil approximately 25 mm in depth. It is to be
understood however, that those dimensions are not essential, and
other dimensions could be satisfactorily employed.
[0101] Although FIG. 12 shows the direction of the tread slope to
be the same for all tyres 47, that is not necessary. Some wheels 45
within the same series may be arranged differently to the other
wheels of the series so that an irregular pattern is formed in the
soil surface. Alternatively, the series of wheels 45 may be moved
in different directions over selected portions of the surface.
[0102] The pattern may be arranged in accordance with the direction
in which the soil surface slopes and/or in accordance with the
direction of the prevailing wind to which the soil surface is
exposed. Different arrangements may be selected according to
whether the main objective is to promote run-off of surface water,
or to minimise wind erosion of the ridges of the pattern.
[0103] A surface having a pattern as described above has the
further advantage of reducing impact stress on the legs of horses,
for example, running over that surface. That is, the ridges of the
pattern tend to collapse beneath the horses hooves so as to absorb
some of the impact load.
[0104] The space between adjacent wheels 45 could be less than or
greater than that indicated by FIG. 12. In the case of a
multi-series arrangement as illustrated by FIG. 13 however, it is
preferred that the space 50 between adjacent wheels 45 is less than
the width of the tyres 47. That is because in such a multi-series
arrangement it is preferred to overlap the wheels 42 as shown in
FIG. 13 so as to ensure maximum application of the embossed
pattern.
[0105] FIGS. 14 to 18 illustrate a preferred embodiment of the
invention in diagrammatic form. Referring firstly to FIG. 14 there
is illustrated a prime mover 100 is operative to pull an assembly
101 over the ground. The prime mover 100 and the assembly 101 are
joined through a connection 102, which may or may not be
releasable.
[0106] The prime mover 100 may provide drive means for operating
the various components of the assembly 101. Alternatively the
assembly 101 has its own drive means. Another alternative is that
each component has its own drive means. It should be appreciated
that where hereinafter a specific component is described as having
its own motor or drive means, that component may source drive means
from the assembly or prime mover.
[0107] The assembly. 101 includes storage means 103 for the fibres
or any of the other additives, flow inducing means 104, separation
means 105, a mixing chamber 106 and soil engaging means 107. The
prime mover 100 is shown as having two sets of ground engaging
wheels 108, but the number of wheel sets could be greater than two
or less than two. The same applies to the assembly 101 which is
shown as having two sets of ground engaging wheels 109.
[0108] In the example shown, the flow inducing means includes a
rotatable device 110 mounted in a chamber 111. The arrangement is
such that rotation of the device 1 10 induces air to flow in a
direction from the storage means 103 towards the mixing chamber
106. The device 110 as shown includes an upstanding rotatable shaft
112 and a drive motor 113 connected to the shaft 112 and being
operable to cause rotation of the shaft. Each of a number of
elements 114 is connected to the shaft 112 to rotate therewith, and
the arrangement is such that rotation of the elements 114 induces
air to flow in the direction as described above. Other arrangements
could be adopted.
[0109] The storage means 103 has an exit opening 115 that can be
selectively opened and closed through operation of an appropriate
valve 116 for example. When the valve 116 is open and the shaft 112
is rotating, the induced air flow draw fibres from the storage
means 103 and causes a stream of those fibres to flow through a
manifold 117 and from there into the mixing chamber 106. As shown
diagrammatically by FIG. 101, the manifold 117 may have a number of
entrance ports 118, and it may have the same or a different number
of exit ports 119.
[0110] In the particular arrangement shown, each of the elements
114 is formed by a length of metal chain. The rotating chains
impact on the fibres flowing upwardly through the chamber 111. Such
impact tends to induce an electrostatic charge in the fibres, and
that has the consequence of encouraging individual fibres to
separate from one another.
[0111] The ground engaging means 107 is preferably formed by a
series of rotatable discs 120 that extends substantially across the
width of the mixing chamber 106. A motor or other suitable drive
means 121 is drivably connected to the discs 120 so as to be
operable to cause those discs to rotate in the direction of arrow A
(FIG. 14). The speed of rotation can be selected to suit particular
conditions, including (for example) the speed with which the
assembly 101 is moved over the ground surface 122. It is preferred
that means be provided to enable adjustment of the depth to which
the discs 120 penetrate into the ground surface 122. One suitable
adjusting means is shown by FIG. 16, and that includes a pivoted
link system 123 connected between the discs 120 and a support, and
a pneumatic or hydraulic system 124 that is operable to alter the
disposition of the link system 123. The axis of rotation of the
discs 120 is transverse to the direction of motion of the prime
mover 100. The axis of rotation may be at a right angle or at some
other transverse angle.
[0112] The discs 120 may be constructed (see FIG. 18) with one or
more blades 150 extending transversely to the plane of the disc
120. Referring again to FIG. 14 when the discs 120 are rotated
while penetrating beneath the ground surface 122, they function to
lift soil from below the surface 122 and cause that soil to flow
upwards into the mixing chamber 106 as indicated by the arrow B
(FIG. 14). In that regard, it is relevant that the mixing chamber
106 as shown is open, or substantially open, at its lower side
adjacent the ground. Fibres entering the mixing chamber 106 from
the manifold 117 collide with the upwardly flowing soil and tend to
mix with the soil. The resulting soil/fibre mix is represented by
the arrow C in FIG. 14. As shown, the soil/fibre mix is induced to
flow downwardly on to the ground surface 122 at a location rearward
relative to the ground engagement means 107. The arrangement is
such that the rotating discs 120 cause the downwardly flowing
soil/fibre mix to mix with loose soil at and below the surface
122.
[0113] The flow of soil, fibre, and soil fibre mix, within the
mixing chamber 106 can be controlled in any suitable manner. In the
arrangement shown a flexible skirt 125 depends from the lower edge
of the chamber 106 and engages the ground surface 122. Escape of
air from the chamber 106 is thereby prevented, or at least
hindered. Control means (not shown) may be provided to enable
adjustment of the skirt 125 in a manner such as to increase or
reduce the potential for air to escape preferably at the rear lower
side of the chamber 106. Other escape means may be acceptable. Such
control can be utilised to vary the soil to fibre ratio in the
final soil based product.
[0114] Other control means could be utilised for that purpose. In
the arrangement shown an adjustable exhaust vent 126 is provided in
a wall of the mixing chamber 106. It is preferred, as shown, that
the vent 126 communicates with an air space 127 within the chamber
106 and which in turn communicates with the general interior of the
chamber 106. In the example shown, the air space 127 is formed
behind a flexible deflectable wall section 128 arranged to promote
appropriate directional movement of the downwardly flowing
soil/fibre mix.
[0115] Whilst FIG. 14 diagrammatically illustrates a substantial
space between an inner surface of the chamber 106 and upper
perimeter of the disc 120, the chamber 106 may be provided with
more or less space. It is desirable to provide for less space than
that illustrated to improve the flow and mix characteristics.
[0116] The roller 129 at the back of the assembly 101 corresponds
to the roller 17 shown in FIG. 3.
[0117] The storage means 103 can be divided into a number of
separate compartments 130, 131 and 132 (FIG. 17), by way of example
only. The number of compartments may vary according to
requirements. In the example shown, the compartment 131 might be
used to store fibres, the compartment 130 might be used to store
particles of resilient material, and the compartment 132 might be
used to store fertiliser. Accordingly a reference hereinbefore to a
soil/fibre mix or to fibres may vary according to the content of
the storage means 103 or a compartment 130, 131, 132 of the storage
means. Other arrangements are clearly possible. The exit opening
115 of each compartment 130, 131 and 132 can be controlled by a
valve 116 as previously described. Each of those valves 116 could
be connected to metering means 133 operable to control the ratio of
materials fed through the metering means 133.
[0118] FIGS. 19 and 20 illustrate an alternate preferred embodiment
of the apparatus according to the invention where same reference as
used hereinbefore refer to like elements. The prime mover 100
illustrated in FIG. 20 pulls the mixing chamber 106 over the
ground, while the storage means 103, separation means 105 and flow
inducing means 104 are located forward of the prime mover 100. The
operation of the mixing chamber 106 and associated apparatus is as
for the embodiment shown in FIGS. 14 to 18 which is shown in FIG.
19 merely for completeness.
[0119] Referring now in particular to FIG. 20, the storage means
103 includes an agitator 220 to agitate the fibre or particles
towards a feed auger 221. The agitator 220 reduces the propensity
for the fibres to bridge or stack before the feed auger 221. The
preferred agitator illustrated includes a rotatable shaft 223
having a plurality of agitating arms 224 extending therefrom.
Rotation of the shaft 223 causes the arms 224 to break up and
agitate the fibres or particles so that they are encouraged to move
towards the feed auger 221.
[0120] The feed auger 221 is used to control the rate of supply of
fibres or particles to the separation means 105. The preferred feed
auger illustrated includes a rotatable shaft 225 with a continuous
helical blade 226 for movement with the shaft 225. The speed of
rotation of the shaft 225 is adjustable to adjust the rate of
supply. The direction of rotation of the shaft 225 is also
adjustable to feed in one direction and unfeed or unblock in the
opposite direction.
[0121] Fibres or particles supplied to the separation means 105 are
treated in accordance with the previous preferred embodiment
illustrated in FIGS. 14 to 18 with the exception that progression
of fibres or particles through the chamber 111 is assisted by a
blower 228. The fibres or particles are supplied to supply conduits
229 linking the separation means 105 with the mixing chamber
106.
[0122] The illustrated embodiment in FIG. 20 has the motor 113
rotating the shaft 112, and through a gear box 230, rotating the
shaft 225 of the feed auger 221. Clearly other drive arrangements
are possible.
[0123] Whilst FIG. 20 does not illustrate a corresponding storage
means, it is envisages that storage hoppers could be positioned
above the agitator 220.
[0124] Various alterations, modifications and/or additions may be
introduced into the constructions and arrangements of parts
previously described without departing from the spirit or ambit of
the invention as defined by the appended claims.
* * * * *