Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF INVENTION
THE RECYCLING OF PLASTICS MATERIAL AND PLASTIC
PRODUCTS OR COMPONENTS, INCLUDING PLASTIC BAGS AND
ENGINEERED PLASTIC PRODUCTS SUCH AS FOUND IN THE
AUTOMOTIVE INDUSTRY, COMPRISING MACHINERY SUITABLE
FOR SUCH RECYCLING AND PROCESSES FOR RECYCLING THE
PLASTICS MATERIAL
FIELD OF INVENTION
This invention relates to a process for converting resultant or
assumed waste plastics material, which is considered contaminated by
plastics and non-plastics contaminating material for example containing
contaminants which are difficult to detect and remove if present, and
recovering the waste plastics for reuse in commercially viable processes
without the need for prior processing such as sorting, separating or
cleaning the plastics from the contaminating materials considered to be
present with the plastics material. This invention also relates to
equipment and machinery useful in carrying out the process and the
product of such process.
BACKGROUND OF THE INVENTION
One of the main problems in recovering any waste materials
is the necessity of sorting the waste stream and separating for example
plastic materials from non-plastic and different plastics contaminating
materials or for example a desired plastic material from other plastic
contaminating materials. For example, when considering recovery of
engineered plastic products such as those found in the automotive
industry, the plastic product may be painted with paint having a
thermoset plastic base. These paints may have a higher melting
temperature than the composite which makes up the majority of the
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product, for example a vehicle bumper. Other products such as radiator
grilles may be covered with a foil laminate. In both products it is difficult
to recover the painted, coated, or laminated plastic because it is virtually
impossible to separate out or remove the coating.
Attempts to rework these products, for example bumpers,
heretofore have been unsuccessful, and the resultant product such as
automotive components have been blemished or deformed sufficiently so
as to result in an unacceptable finish being applied thereto. For example,
when bumpers are reclaimed, the coating particles may be large enough so
as to cause blemishes and deformities on the surface of the bumper, to
unduly affect the coating process. The resultant is that expensive
engineered products become even more expensive as a result of these
heretofore unreclaimable, unacceptable products and/or components.
In another example, when attempting to recover the plastics
material in plastic bags returned to supermarkets, it has been found that
such lots of bags returned may contain contaminants such as paper, fruit
remnants, metal cans, bottle caps, packaging and other random materials.
It is prohibitively expensive to sort these contaminating materials prior to
reclaiming the plastic.
It has been proposed in the prior art in recovering plastic to
add to the plastic as processed in a mixer a predetermined amount of
refuse which has been dried and ground. An example of such a process is
found in United States Patent No. 5,035,189. Of course with this process
the refuse must have been presorted dried and ground prior to being
dispensed into the mixer of the process. This luxury is not afforded
generally in the real world and as such the teachings of United States
Patent No. 5,035,189 is only of particular application when one knows the
constituents of the product streams. There is no discussion within this
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reference as to the encapsulation of each finally divided particle within
the waste stream. Further the contaminating material which is
undesirable does not arrive in a random manner.
Other examples of plastic recovery systems or components are
found in United States Patent No. 3,421,405, United States Patent No.
4,626,189, United States Patent No. 4,824,627 and United States Patent No.
4,187,352. Like United States Patent No. 5,035,189 all of these references
require knowledge of the product streams; that is to say none of the
contaminating material arrives randomly with the plastics material to be
recovered or reclaimed.
Applicant is also aware of United States Patent No. 4,874,566
issued October 17, 1989 and United States Patent No. 5,032,072 issued July
16, 1991 and claiming priority from United States Patent No. 4,874,566,
being a divisional thereof, and teaching the processing of thermoplastics
received in a non cleaned and non sorted state. The final output of said
method or process includes molded finished products. Applicant is also
aware of United States Patent No. 4,185,784 which teaches the use of a
roller extruder device which crushes non plastic waste carried in the
plastic received. No comminuting to a fine grind of the undesirable
contaminants is taught however in either reference.
Nowhere within the prior art is there taught the handling of
unsorted contaminated plastic materials or coated plastic products or
components wherein the method and the process includes steps and an
apparatus for comminuting plastics material, either being coated or
having undesirable contaminants therewith, while said plastics material
is in a plasticized state. This process provides a distribution of the
contaminants or coating within the plasticized material and hence the
final products recovered and the contaminants of a much reduced particle
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size so as not to affect unduly further processing or use, of the recovered
or reclaimed plastics material or product in a commercially viable process.
This process is therefore superior to any process or method or machine
found in the prior art.
It is therefore an object of the invention to provide a process
for recovering plastic materials or products or components that are
considered waste because it is considered to have unsorted undesirable
contaminants or coatings associated therewith (for example contained
therein or thereon) wherein the output of said processing includes finely
dispersed particles of the contaminants or coatings encapsulated within
the recovered plastics material which contaminants do not adversely
affect the ability to further process the recovered or reclaimed plastics
material into viable products.
It is a further object of the invention to provide a method for
accomplishing the above objective, and the finished products of both the
method and the process.
It is yet a further object of the invention to provide an
apparatus, machinery and components therefore for comminuting
plastics materials having carried therewith undesirable contaminants or
being coated with said undesirable contaminants, the comminuting of the
refuse occurring while the plastic is in a plasticized state.
Further and other objects of the invention will become
apparent to those skilled in the art when considering the following
summary of the invention and the more detailed description of the
preferred embodiments illustrated herein.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a
method for reclaiming, recovering waste plastic or coated plastic products
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and/or components for example engineered plastic products or
components which are normally coated with a paint, foil laminate or the
like, or for example plastic bags, which may contain randomly undesirable
contaminants (for example cans, food remnants, paper, cigarette butts,
(metal or plastic) bottle caps, packaging or the like), said method
comprislng:
(a)i in one embodiment grinding the plastic or product or
component as received onsite, or in another
embodiment having the material ground offsite, to a
predetermined particle size (in one embodiment less
than 3/8") so as to grind both the plastic and the
contaminants including in one example the coating
randomly contained with the plastic, if the
contaminants or solid, or coating some of the surface
of the sized particles, when the contaminant is a
coating, or
(a)ii receiving the material in an as is condition,
(b) accumulating said waste plastic, (preferably in a feed
hopper, so as to provide a substantially continuous
flow of the waste plastic), (for example so as to
minimize the amount of air fed with said material to
an extruder),
(c) heating and pressurizing said material within an
extruder, (preferably a twin screw extruder with flights
rotating in opposite directions), the extruder being
preferably vented to extract unwanted gases, to a
predetermined temperature and pressure so as to
plasticize said plastic within which said contaminants
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are contained, or within which said coating is
contained,
(d) delivering, for example extruding, said plasticized
plastic material containing said contaminants and/or
coating to a comminuting device, and preferably an
apparatus having devices (and preferably plates), at
least one of which moves relative to another, for
example moving in relation to one another (and
preferably alternate plates rotating relative to
stationary plates), each of the devices having means to
allow passage of plasticized material, and preferably
openings therein preferably of substantially equal size,
wherein said plasticized plastic material containing
said contaminants and/or coating passes consecutively
through means to allow passage of plasticized material
thereby mixing the plasticized material and at the
same time shearing the contaminants and/or coating
progressively, thus comminuting each of said
contaminants and/or coating to a very fine
predetermined particle size, preferably to less than 20
mesh, thereby providing finely disbursed particles of
the contaminants and/or coating of predetermined
size throughout the plasticized plastic material,
(e) preferably collecting and preferably in one
embodiment pelletizing said plasticized plastic
containing said finely comminuted and divided
contaminants and/or coating to provide feed stock for
any further plastic handling or forming process such
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as a film line or an extrusion or a molding process, or
an engineered product or component manufacturing
process, for example automotive components such as
bumpers, radiator grilles, door panels, mirror
housings, head or tail light housings or the like,
wherein said plastic material contains finely comminuted and divided
contaminants and/or coatings within the plastic, each finely divided
particle of waste material and/or coating being encapsulated by plastic and
being sufficiently dispersed or separated from one another so as not to
affect unduly, for example weaken, any product made from the plastic. In
a preferred embodiment said pellets are used to manufacture plastic bags
and wherein each particle of contaminant is randomly dispersed
throughout the plastic of the bag without unduly effecting the strength of
the plastic bag and it's ability to retain its expected contents in use and
preferably the plastic bags being manufactured by said method are plastic
garbage bags. In another embodiment said pellets are used as raw
material for a molding process or an extrusion to manufacture articles
normally molded or extruded from thermoplastic material, for example
automotive products and/or components such as bumpers, radiator
grilles, door panels, mirror housings, head or tail light housings or the
like.
According to yet another aspect of the invention there is
provided a process for recycling recyclable plastics contaminated and/or
coated with undesirable contaminant materials such as metal, or paint, or
foil laminates, said process comprising means for accumulating unsorted
waste plastic material, in one embodiment in communication with a first
grinding means for grinding said waste plastic material containing
contaminant materials and the contaminant materials to a predetermined
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size, extruding means for heating and pressurizing said plastics and
contaminant materials to a predetermined temperature and pressure to
plasticize said waste plastic material and contaminant material and
extruding the material from said extruding means, the plastic waste in a
5 plasticized state and containing said contaminant materials, and when no
grinding apparatus is present said extruding means preferably being a twin
screw extruder with two or more flights rotating within the barrel in
opposite directions to one another to thereby reduce the size of the waste
handled without prior grinding, comminuting means for receiving said
10 waste from the extruding means and comminuting the plastic and
contaminant materials while still in a plasticized state thereby reducing
the particle size of the contaminant materials and distributing said
contaminant materials within said plasticized plastic so as not to affect
unduly the plastics products produced or any further process being carried
15 out, said plasticized plastic and contaminant materials exiting said
comminuting means as a mixture, preferably collecting and in one
embodiment preferably pelletizing said matrix of the plastic and
contaminant materials, means to collect and preferably pelletize said
mixture accumulated for use as feed stock to a plastic forming process, and
20 wherein the particles of finely divided contaminant materials are
encapsulated with plastic and so widely distributed from one another
within the plastic that the presence of the finely ground contaminant
materials do not unduly affect, for example weaken, the final product
being made from the material or any further process being carried out. In
25 a preferred embodiment the output of said process is used for the
manufacture of plastic bags and wherein each particle of waste is so finely
distributed (separate) from others so as not to unduly affect the plastic bag
structure, preferably wherein said bag making process is a garbage bag
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manufacturing process.
In a preferred embodiment said means for comminuting said
plasticized plastic further comprises a machine having a housing, said
housing having a space defined therein wherein a driven shaft is
5 disposed, said housing and driven shaft for supporting a number of
devices at least one of which is moveable relative to another (and in one
embodiment said devices comprising stationary and non stationary
plates, said stationary plates containing therebetween a non stationary
plate driven by said shaft) wherein plasticized plastic material having
10 carried therewith contaminant materials pass through openings within
said devices resulting in the shearing of the contaminant materials as the
plasticized matrix moves from openings of one device to openings in
another device, and preferably when stationary and non-stationary plates
are utilized, through the openings when aligned, between adjacent plates,
15 by moving into relative alignment of the openings of one plate relative to
the other, said shearing of the plastic matrix carrying contaminant
materials occurring between the devices and preferably between non
stationary and stationary plates. Preferably said machine includes a
predetermined number of sets of stationary and non stationary plates,
20 wherein the machine provides a mixture of plasticized plastic and finely
ground contaminant materials as output from said machine.
According to yet another aspect of the invention there is
provided a machine for comminuting a contaminating material (for
example non-plastic and/or plastic material) and/or coatings within a
25 plasticized (plastic) matrix, said machine comprising means for
comminuting said contaminating material and dispersing said
contaminating material throughout said plasticized matrix, said means
for comminuting said contaminating material having at least one stage,
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each stage including first means and second means which cooperate to
shear the plastic material and contaminating material proximate the
portions of the first and second means adjacent one another, to disperse
and comminute said contaminating material throughout the plasticized
(plastic) matrix wherein the finely comminuted contaminating material is
distributed throughout said plasticized material so as not to affect unduly,
for example degrade, any use to which the plasticized material when
solidified may be put or any further processing of the plasticized material
to be carried out. In a preferred embodiment the finely comminuted
contaminating material (whether plastic or non-plastic) distributed
throughout said plasticized material will not unduly affect or degrade any
use to which the plasticized material when solidified may be put. In one
example, because of the distribution of the contaminating material in the
plastic material and the small size of the contaminants the output of said
machine can be used in the manufacture of plastic bags and preferably
garbage bags.
In another example, the distribution of the contaminating
material (which was originally a coating) in the plastic material is so
distributed and the particle size of the contaminating material is so small
that the output of said material can be used to manufacture engineered
plastic products and/or components, for example those products and/or
components found in the automotive industry for example, bumpers,
plastic door panels or the like, radiator grilles, housings for mirrors or
headlights or tail-lights and other conventional products.
In a preferred embodiment, the machine for comminuting a
contaminating material is integral with an extruder with each of the
comminuting stages of the machine being separated by flights of the
extruder, preferably one of the stages further carrying a pair of plates (and
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preferably moveable and stationary plates), the plates being moveable
with respect to one another by the rotation of the extruder, preferably a
drive shaft of the extruder flights also during the movement of the plates
with respect to one another.
In one embodiment said means for comminuting said
plasticized plastic may further comprise a machine having a housing, said
housing having a space defined therein wherein a driven shaft is
disposed, said housing and driven shaft for supporting a number of plates
at least one of which is moveable relative to another [in one embodiment
including alternating stationary and non-stationary (for example rotatable
or oscillating)] plates, said moveable plates being driven by said shaft,
wherein plasticized plastic material having carried therewith
contaminant materials, for example non-plastic and/or plastic material
and/or coatings, passes through openings within said plates resulting in
the shearing of the contaminant materials as the plasticized matrix moves
through the means for comminuting for example from plate to plate to
plate, said shearing occurring between relatively moveable plates,
preferably said machine including a predetermined number of sets of
plates so as to provide a mixture of plasticized plastic and contaminant
materials of very fine size (for example each piece of contaminant
material being less than 0.050 inch) as output from said machine.
According to yet another aspect of the invention there is
provided a plastic product comprising a matrix of plastic material which
contains therein, preferably encapsulated therein, a comminuted finely
sized randomly distributed amount of particles of undesirable
contaminant material, whether plastic or non-plastic and/or coatings,
sized and spaced from one another so as not to affect unduly, for example
degrade, the properties of any finished plastic product comprising such
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product or any further process being carried out employing such plastic
matrix carrying the contaminant materials. Preferably said product is
plastic film. In one embodiment said plastic film is utilized to
manufacture garbage bags.
In another embodiment, the product is a coated engineered
plastic product or component such as those found in the automotive
industry, for example bumpers, door panels or the like, radiator grilles,
mirror housings, head and/or tail-light housings or the like. radiator
grilles, mirror housings, head and/or tail light housings, or the like.
According to yet another aspect of the invention there is
provided a product comprising a matrix of plasticizable and extrudable
material which contains or carries, and preferably encapsulates, therein a
comminuted finely sized randomly distributed amount of particles of
undesirable contaminant material, the particles sized so as not to affect
unduly, for example degrade, the properties of the finished product or any
further process being carried out using that matrix.
In another embodiment, the product is a coated engineered
plastic product or component such as those found in the automotive
industry, for example bumpers, door panels or the like, radiator grilles,
mirror housings, head and/or tail-light housings or the like. radiator
grilles, mirror housings, head and/or tail light housings, or the like.
In a preferred embodiment of the products referred to above
the contaminants are less than about 20 mesh (.050 in.).
In a preferred embodiment of the methods or processes
identified above the contaminants are so fine that they do not plug the
openings of film die's through which the plastic material carrying the
comminuted contaminants pass for forming the film which film dies
openings are usually in the range of .065-.085 inches which if plugged
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would create a die line in the film manufactured if the contaminants were
too coarse.
In a preferred embodiment of the processes described above
the contaminants are ground so fine ( in the order of .0015 in.) that they
5 minimize the aspect of plugging the openings of film dies which openings
are usually in the range of .065-.085 inches which if plugged would create a
die line in the film manufactured if the contaminants were too coarse.
In another embodiment of the methods, processes, and
products described above for the original product or components being
10 reclaimed is an engineered plastic product, preferably coated with paint,
for example a thermoset plastic based paint or coated with foil laminate.
Examples of such products/components are found in the automotive
industry such as bumpers, door panels or other plastic panels, head or tail
light housings, and mirror housings and the like. The plastic matrix
15 created has the contaminating material which was previously a coating so
finely divided and distributed within the reclaimed material so as not to
affect unduly any finished engineered plastic product made from the
reclaimed material, for example bumpers, door panels or other plastic
panels, head or tail light housings, and mirror housings and the like. In
20 another embodiment, the contaminents are so finely divided and
distributed so as to minimize the surface deformation and blemishes of
any engineered product/component being manufactured from the
reclaimed materials, and thereby allow coating of the product with an
acceptable surface finish to the end user.
25 BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be illustrated with reference to the
following drawings illustrating embodiments of the invention in which:
Figure 1 is a flowchart indicating the steps within a method
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for reclaiming plastics materials considered (believed) to contain
contaminants illustrated according to one preferred embodiment of the
invention.
Figure lA is a flowchart indicating the steps within another
method for reclaiming plastics materials considered to contain
contaminants illustrated according to another preferred embodiment of
the invention.
Figure 2 is a process equipment flowchart of machinery used
in one preferred embodiment of the invention to recover the unsorted
waste plastic stream.
Figure 2A is a process equipment flowchart of machinery
used in another preferred embodiment of the invention to recover the
unsorted waste plastic stream.
Figure 2B is another preferred embodiment similar to Figure
2A.
Figure 3 is a general perspective view of components of the
comminuting apparatus of Figure 2.
Figure 4 is a cut away cross sectional view of the apparatus of
Figure 3 illustrating stationary and non-stationary plates contained
within the housing and illustrated in a preferred embodiment of the
invention.
Figure 4A is a schematic view of another comminuting
apparatus with concentric cylinders having openings therein and
illustrated in an alternative embodiment of the invention.
Figure 4B is a schematic view of another comminuting
apparatus with an outer cylinder having openings therein within which
a number of radially extending cutting blades rotate, illustrated in a
further alternative embodiment of the invention.
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Figures 4C-4F are alternative embodiments to Figure 4.
Figure 5 is a partially cut away perspective view of a film
product of the process of Figure 2 and the method of Figure 1 used to
make plastic bags, a cut-away portion of which is illustrated in a preferred
5 embodiment of the invention.
Figure 6 is a schematic diagram of the size reduction process
of contaminants that takes place in the comminuting device of Figure 4 as
the openings of the moveable plates pass openings of other plates
illustrated in a preferred embodiment of the invention.
Figure 7 is a front view of a stationary plate used in the
comminuting device of Figure 4.
Figures 8 and 8a are a front views of rotating plates used in
the comminuting device of Figure 4.
Figure 9 is an alternative embodiment of the invention.
Figure 10 is an alternative embodiment combining an
extruder and a comminuting device.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
Referring generally now to Figure 1 there is illustrated in a
block diagram flow chart, a method of recovering waste polyethylene and
20 making the waste polyethylene into a useful product. For example
consumers purchase their groceries often in plastic bags supplied by the
supermarket chain. These plastic bags are either thrown away or used
around the household to collect waste and ultimately are an extra burden
in the waste stream. Because polyethylene does not readily breakdown,
25 many supermarkets, attempting to be good corporate citizens, will collect
these bags. However the bags often arrive at the recycling depot
containing pop cans, pieces of fruit, milk cartoons, bottle tops, metal,
plastic, and other miscellaneous wastes. It is very difficult for the
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supermarket then to recycle these bags. In fact efforts have been made to
do so without any success. Since in the manufacture of plastic film, used
in plastic bags, film dies are used, it has been difficult to establish a
method and the equipment to carry out a method of preventing the waste
5 from plugging the die gaps of the film producing units or interrupting the
film drawing process. The present invention therefore obviates this
problem by providing means for reducing the particle size of the
undesirable contaminants so as not to plug the die holes in for example a
film producing line and thereby substantially reducing the presence of
10 highly undesirable die lines. These die lines when present result in a
need to completely rework the film made.
Milk is sold in polyethylene pouches, usually sold three to a
poly bag, at supermarkets, convenience stores and the like. Dairies are
usually required to retrieve from outlets any milk that is not sold in a
15 predetermined period of time and dispose of the final product as well as
the packaging. While the milk may be poured from the poly bags,
generally the contaminated polybags are thrown away.
The method of Figure 1 and all of the description in relation
to Figures 1 to 9 includes the recycling of many types of plastic and
20 particularly polyethylene and may be used for the recycling of waste bags.
For example should the polyethylene be contaminated with polystyrene
wherein a large percentage of the material stream is polyethylene then the
polyethylene may be recovered using Applicant's method as well. The
contaminants which are undesirable may also be thermoset plastics, that
25 is the contaminants need not be metal, cardboard, cigarette butts, and food
remnants, but may also be other types of plastic which are just as
undesirable.
It is also been found that floor sweepings from plastic plants
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along with the normal accumulated dirt found on floors can also be
recycled following the same method.
The present method has been carried out on combinations of
materials which have been ground; for example a combination of 50%
5 ground polyethylene bags containing no undesirable contaminants and
50% ground polyethylene containing undesirable ground contaminants
has been used for making film. Various percentages and proportions of
these materials have been attempted with the best success being found at
rates where reprocessed plastic is at a rate greater than or equal to 50% and
10 densified contaminated plastic not greater than 50%, based on shopping
bags which are ground, yielding a very good quality plastic film which can
be readily made into bags. It has been found that because of the ink in
many of the shopping bags that the final product from the process is
darker than would be acceptable in making light coloured products.
15 Although this has not been reproduced it is well known to de-ink
materials before processing. The reader is informed to de-ink if lighter
coloured finished products are desirable. 100% contaminated plastic has
been produced and does give a good end product. Specifications of the
end product can be adjusted by including some % new materials or
20 commercially available modifiers.
Referring now to Figure 1 there is described a method of
recovering the aforementioned waste plastic. In one embodiment
described in the remainder of the detailed description of the preferred
embodiments it has been found that a good source of raw materials exists
25 in reprocessing waste poly bags or shopping bags. Therefore it is in this
direction that much of the experimentation and effort to perfect and
render to practice the method and following process has been directed.
Therefore in Figure 1 the waste plastic bag is received by the
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supermarket, containing undesirable contaminants as shown in the first
block of Figure 1, (or engineered plastic products such as automotive
products such as plastic bumpers, door panels, mirror and light housings).
These bags and engineered products are individually collected and
5 handled by any conventional material handling system for example
baling, compacting, shredding or the like. The plastic is then picked up by
the reprocessing agent.
The waste plastic containing the undesirable contaminants is
then ground (keeping like plastics materials together) to a size suitable for
10 bulk handling either pneumatically or by other known bulk handling
methods. For example the material may be ground to a size finer than 4
mesh so that it may be readily handled. After the material is handled and
placed through the grinder it may be conveyed to a suitable hopper for
collection of the raw materials to be fed to an extruder. This hopper may
15 be of any known size and contain any conventional material handling
equipment. For example a bulk silo or a container may be provided with
an auger at the outlet thereof to feed the material into a surge hopper in
advance of the extruder. The hopper may also include drying facilities to
ensure the waste plastic is dry. For example some plastic is hygroscopic
20 and picks up moisture. One such plastic material is XenoyTM, a
polycarbonate produced by General Electric. Polyesters are also
hygroscopic. Thus the drier permits the preparation of the plastics
material in the same manner as virgin material would be prepared as is
known in the art. One such drier is sold under the trade mark ARID-XTM
25 by DRI-AIR Industries Inc. of Vernon, Connecticut. This drier can be
hooked up to hoppers produced by others and comprises hoses and
blowers for blowing hot air up the hopper (the direction opposite the flow
of material into the extruder).
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`_
It is important to recognize that in grinding the plastic stock
none of the contaminants have been removed. The grinder therefore
must be of suitable durability to grind abrasive materials such as for
example, metal pop cans, or other contaminants similar to the nature of
5 metals.
The material is then fed into an extruder which has heating
elements located along the barrel thereof at numerous locations. The
extruder used in the experiments carried out included a 2.5 inch barrel.
The extruder is pre-heated to 205C, which is the operating temperature,
10 and pressurized to 5,000 PSI. The purpose of the extruder is to convert the
plastic (for example polyethylene from the bags, polycarbonate from
automobile bumpers which has been dried) to a plasticized state so that it
may be readily handled prior to forcing the plastic under pressure into an
in line comminuting device. The in line comminuting device which is a
15 preferred embodiment therefore further comminutes the particle size of
the undesirable contaminants contained with the plasticized plastic
flowing through the process to a particle size so that the particles will not
plug the dies of a plastic film manufacturing line for example, or interrupt
the film drawing process (when polyethylene is the plastics material being
20 processed) in another example. In order to effect this requirement
therefore it is desirable to be able to vary the output of the comminuting
apparatus. The contaminants are sized to insure that they do not
adversely effect any process to which the recovered plastic material may be
subjected to -- film forming for bags, remanufacture of bumpers from the
25 processed polycarbonate and thermoset paint carrying reclaimed bumpers.
For example normally in the process at least a 20 mesh screen
or breaker plate and presently a 40 mesh screen, is in line following the
comminuting apparatus to prevent any large particles from passing on
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through to the next step in the process. However it is preferred that the
recovered plastic material containing the undesirable contaminants be
pelletized so that they may be inventoried and used as feed stock in the
production of plastics products. Each particle therefore of the undesirable
5 contaminants is divided so finely so as not to effect unduly adversely any
finished product. Each particle of contaminants therefore is encapsulated
with plastic and distributed randomly through the plastic. It has been
found that the particles are less than 1 mm and in many cases in the order
of .0015 inches in many of the experimental runs conducted. It is preferred
10 that the pellets be manufactured first even if the products will ultimately
be plastic bags or other molded products since in manufacturing the
pellets one may readily supply the output as raw material to end users.
Products which may be made from the recovered plastics
material with the finely divided undesirable contaminants are such
15 things as garbage bags, garbage cans, plastic pipes, pails, shovels,
automobile bumpers, light housings, door panels, or other product in
which such recovered plastics may have use.
Referring to Figure lA there is illustrated a method similar
in many respects to that which has been described in relation to Figure 1
20 with the exception that grinding is not necessary before introducing the
material into a twin screw extruder which because of the nature of the
oppositely rotating screw augers tends to shred and handle the material
sufficiently well so as to render grinding as unnecessary in most instances.
The purpose of the twin screw extruder is to convert the polyethylene
25 plastic to a plasticized state so that it may be readily handled prior to
forcing the plastic under pressure into an in line comminuting device.
The in line comminuting device, which in a preferred embodiment
thereof further comminutes the particle size of the undesirable
2121 72~
-_ - 21 -
contaminants contained with the plasticized plastic flowing through the
process to a particle size so that the particles in one aspect of the invention
will not plug the dies of a plastic film manufacturing line or interrupt the
film drawing process. The end uses and description relating thereto
5 remains the same.
Referring now to Figure 2 there is illustrated a schematic
flowchart of the process for handling of waste grocery bags containing
contaminants which are received and fed to the process 5. The waste
grocery bags 15A are fed through a hopper 10 to a grinding apparatus 20.
10 The grinding apparatus 20 therefore grinds the plastic bags containing the
contaminants as shown into a coarse ground dry state, sized properly for
the extruder and preferably to a grind of material that passes through a 4
mesh screen. The details of the grinding apparatus 20, have not been
provided. However a suitable grinder may be Model Condor 1000
15 manufactured by FABRICA BONDENESE MACHINE of Italy, the
specifications and construction for which are incorporated herein by
reference. Irrespective of the make of the grinder should be rugged and be
able to grind metal and perhaps stone.
A hopper 30 therefore is provided to collect the coarse
20 ground plastic material containing the contaminants 15b. This material is
then fed by gravity into an extruder which has a flight 45 for moving the
material toward the comminuting device 50. Various heating sections
(not shown) are provided within the extruder to conduct heat to the dry
course ground material 15b so that the extruder 40 with the flights 45 can
25 conduct the material in a plasticized state 15c together with the
undesirable contaminants. The extruder may be Model FD65
manufactured by FUTURE DESIGN OF BRAMPTON, Ontario, Canada,
and whose specifications and construction are incorporated herein by
-22- 212172~
_.
reference.
In line with extruder 40 having various heating elements,
also known in the art, is provided a comminuting device 50 which has a
number of moveable (in this case rotatable), and stationary, plates as best
5 seen in Figure 4 which will be described hereinafter. The extruder and the
comminuting device through to the end of the process provide a
continuous process (passage) to ensure that the plastic remains in the
desirable plasticized state. The comminuting device 50 therefore controls
the size and dispersion of the contaminants in the matrix to provide a
10 continuous output from the comminuting device to the respective
process 1, 2 or 3 such that the contaminants are sized so that they pass
through a 20 mesh screen easily and in the case of a film line, item 1, they
do not plug the dies of the film line which are normally in the range of 65
thousandths of an inch to 85 thousandths of an inch or interrupt the film
15 drawing process. It has been found that 40 mesh size which is 25
thousandths of an inch will sufficiently accomplish this task. This is one
of the largest problems in recycling the polyethylene containing the
contaminants since most film processors do not have the ability and
resources to recover the plastic without excessive sorting. The present
20 process includes the comminuting of the contaminants to a size less than
40 mesh and preferably below 1 mm in size and in most cases in the order
of .0015 inches, with each particle being encapsulated in (being entirely
surrounded by), the plasticized matrix. Therefore the comminuting
device 50 feeds the plasticized matrix containing highly divided and
25 comminuted contaminants to a preferred pelletizer die 3 wherein the
material 15d is pelletized to be used in a molding process or the
manufacture of plastic film at items 2 and 1 respectively. The film line
may be manufacture FUTURE DESIGN, BRAMPTON, Ontario, Canada,
- 23 - 2 1 2 1 72 ~
._
Model No. FD1500, which specifications and details are hereby
incorporated by reference. The injection molder may be Model No.
DUOMAT 215, manufactured by ECKERT & ZIEGLER Gmbh. of
Wesissenburg, Germany, which specifications and details are hereby
5 incorporated by reference.
The comminuting device is driven independently of the
extruder of the preferred embodiment although the operation is
continuous with the extruder. By providing a variable speed drive with
the comminuting device 50 so that the revolutions per minute might be
10 varied, and/or by varying the process throughput, and/or by varying the
sizing of the plate openings as best seen in Figure 7 and 8, the size of the
particles of the undesirable contaminants may be easily controlled.
Further the number of plates may increase the comminuting surface
available within the comminuting device. Other comminuting devices
15 not employing plates may work equally well with the plasticized plastic
matrix providing they are able to reduce the size of the undesirable
contaminants to the appropriate size so as not to affect unduly the
finished product of recovered plastics.
Referring now to Figure 2A there is illustrated another
20 schematic flowchart of the process for handling of waste grocery bags
containing contaminants which are received and fed to the process 5a.
The waste grocery bags 15a' are fed through a hopper 30a without the need
for a grinding apparatus 20 as in figure 2. The hopper 30a therefore is
provided to collect the unground plastics material containing the
25 contaminants 15a'. This material is then fed by gravity into an twin screw
extruder 40a which has two flights 45a moving in opposite directions (S1
and S2) pushing the material toward the comminuting device 50. As they
do so, they reduce the size of the contaminants 15a'. Various heating
2121725
- 24 -
sections (not shown) are provided within the extruder to conduct heat to
the dry material 15c' so that the extruder 40a with the flights 45a
including oppositely rotating screws S1 and S2 can conduct the material in
a plasticized state 15c' together with the undesirable contaminants.
In line with extruder 40a having the various heating
elements, which is known in the art, and may be Model DOKEX 2-500
manufactured by PROMAG, S~ LAND, is provided a comminuting
device 50a which has a number of moveable (for example rotary), and
stationary, plates as best seen in Figure 4 which will be described
hereinafter. It is important that the twin extruder and the comminuting
device through to the end of the process be a continuous process (be in
communication with one another) so as to ensure that the plastic remains
at the desirable plasticized state. The comminuting device 50a therefore
sizes the contaminants so that the output of the comminuting device to
the respective process la, 2a or 3a is continuous with the contaminants
being sized so that they pass through a 20 mesh screen easily and in the
case of a film line, item la, they do not plug the dies of the film line which
are normally in the range of 65 thousandths of an inch to 85 thousandths
of an inch or interrupt the film drawing process. It has been found that 40
mesh which is 25 thousandths of an inch will sufficiently accomplish this
task.
Referring now to Figure 3 there is illustrated in perspective
the comminuting device 50 shown detached from the extruder at one end
and detached from the process die for pelletizing at the other end. The
comminuting device 50 is illustrated having a housing 51 which is readily
attachable at one end to the extruder and at the other end to the process
die. A drive H is provided which as previously discussed is a variable
speed drive which is more convenient than changing the size of the
-25- 21217~
sprocket 52 from time to time as processing requirements dictate.
Referring now to Figure 4 there is illustrated in cross section
the comminuting device 50 and the housing 51 having an opening
contained therein through which a drive shaft D extends. The opening
5 indicated as generally O1 contains a number of stationary and moveable
plates, S1 to S5 being the stationary plates and M1 to M4 being the
moveable plates. The moveable plates are keyed to the drive shaft D via
the keys K1, K2, K3 and K4 within key-ways, not shown in Figure 4, best
seen in Figures 7 and 8. The key-ways KW2 therefore of Figure 8 are used
10 to secure the plates M1 to M4 on the shaft D. The stationary plates S1 to S5
are keyed to the barrel of the housing 51 at keys K5, K6, K7, K8 and K9.
Spacers P1, P2, P3 and P4 are provided radially above each plate M1, M2,
M3 and M4 which in fact are collars which circle the plate and keep the
spaces between the stationary and moveable plates well defined.
Referring now to Figure 4A there is illustrated a schematic
view of another comminuting apparatus 100 with concentric cylinders
110 and 120 having openings therein 110a and 120a which provide the
configuration to perform the necessary comminuting of the particles
between the inner diameter of the outer cylinder 110 and the outer
20 diameter of the inner cylinder 120. The comminuting therefore works
along the lines of the principles described in relation to Figure 6. However
to accomplish the task properly it will be necessary to provide a number of
devices as illustrated in Figure 4A in series to properly control the
comminuting of the particle sizes or concentric cylinders (having a
25 common axis) of reducing diameter some of which may be stationary and
others moveable, so that there is relative movement between the
cylinders.
Figure 4B is a schematic view of still another comminuting
212172S
- 26 -
apparatus with an outer cylinder 140 fed from a connector 130 from the
extruder wherein an outer drum 145 having openings 145a is provided
within which a number of radially extending cutting blades 150 rotate
which provide the necessary comminuting of the particles between the
inner diameter of the outer cylinder 145 and the cutting blades 150 of the
inner wheel 160 as the plasticized material passes through the holes and
engages the blades 150. The comminuting therefore works along the lines
of the principles described in relation to Figure 6 with the material M2
containing finer particle sizes than material Ml. However to accomplish
the task properly it will be necessary to provide a number of devices as
illustrated in Figure 4B in series to properly control the comminuting of
the particle sizes.
Referring now to Figures 7 and 8 there is illustrated the
design of the stationary plates in Figure 7 and the moveable plates in
Figure 8. Openings therefore hl are provided on the exemplary plate S2
which has a key-way KWl provided for attachment to the barrel of the
comminuting device 50. The width of the plates is 1/2 inch and is
manufactured from substantial tool grade steel which plates are finished
flush and having substantially zero clearance when installed within the
comminuting device. Each plate has approximately 650 holes provided in
the patterns shown which are compatible with the design of the movable
plate Ml of Figure 8 having holes h2 as indicated. The plate Ml being
exemplary of all moveable plates has a key-way KW2 for attachment to
drive shaft D of Figure 4. The holes are defined as generally circular
having predetermined diameters and positions. The holes in Figures 7
and 8 therefore are defined from the inner diameter which is 5 inches
plus or minus a thousandths of an inch and are defined in 8 concentric
rings of openings with the first ring providing 60 holes separated by 6
212172~
- 27-
degrees and with the eighth ring providing 103 holes separated by 3
degrees 30 minutes. These are identically positioned for both the
stationary plates of Figures 7 and the moveable plates of Figure 8. The
stationary plates of Figure 7 are manufactured from 1/2 inch metal plate,
5 wherein the moveable plates are manufactured from 3/4 inch plate
because of the fact that the moveable plate is keyed to the shaft which has
less of a mechanical advantage then the outer diameter of the plates for
the stationary plates which are keyed to the barrel of the housing 51. The
holes are " in diameter.
An alternative to the plates of Figures 7 and 8 is illustrated in
relation to Figure 8a. The effective principals of Figure 8a to the reduction
in size of the contaminants as described in relation to Figures 6 are
identical. The fastening of the moveable plate to the rotating shaft via a
key and key-way kW is identical to that of Figure 8. Radial openings H2'
15 therefore are provided, on one side of the plate which open into slots H3
bounded by the cutting surfaces. The slots and shearing surfaces therefore
are angled at approximate 3 degrees to the horizontal with the openings
0.1 disposed on the other side of the slots, on the other side of the plate,
and providing passage for the plasticized material to pass through the
20 openings and thereby be sheared proximate the junction of the stationary
and moveable plates, as described in relation to Figure 6. Again as with
Figure 8 the openings of Figures 8a are arranged in concentric rings, a total
number 8, and the moveable plates are manufactured from Tool Grade
Steel at 3/4" thickness, since the moveable plate is keyed to the driven
25 shaft, and has less mechanical advantage then the stationary plates as
previously described. It is recommended that the cutting surfaces of
Figure 8a be sufficiently thick so as to not bend or deform during
operation thereof, as a result of shearing metal particles. However, the
212172~
- 28 -
structure of Figure 8 is much preferred, although the structure of Figure
8a would work.
The holes therefore provide the cutting of the undesirable
contaminants as the extruder feeds the 205C plasticized plastic containing
5 the undesirable contaminants at 5,000 PSI to the comminuting device
which contains in essence as best seen in Figure 4 four movable plates. If
we assume that the pressure is coming from the direction shown A1 then
because of the tolerances in manufacture of the plates the moveable plates
will tend to move toward the leeward edges, where most of the grinding
10 is done, since a very small gap will appear between the stationary plates
and the pressurized edges of the moveable plates. For example plate M1
will grind primarily on the right hand edge adjoining the stationary plate
S2 although some grinding will take place on the left hand edge adjoining
stationary plate S1. This is expected since zero clearance is not
15 recommended since the machine will take a great deal of horsepower to
overcome the internal friction thereof. However the tolerances are kept
small so that some comminuting does occur on the pressurized edge. It is
recommended that plates S1 to S5 and M1 to M4 be ground flush and be
nitrated and made from tool grade steel. The details of the grinding or
20 comminuting will be described in relation to Figure 6.
Referring now to Figure 6 there is described in schematic
form the comminuting of a particle 1 as it passes through a selection of
plates. As indicated therefore the particle 1 enters the stationary plate S1 at
the first opening thereof. The particle as it engages the moveable plate
25 opening M1 instantaneously will be sheared to create a remnant la
remaining in the hole of the plate S1 with a divided portion b being
carried through under 5,000 PSI with the plastic matrix. The particle b
therefore in being moved by the plastic matrix will move through the
21~17~
- 29 -
opening Ml until the particle reaches the other end of the opening of the
plate Ml whereat because of its engaging edge with hole 2 of plate S2,
which is 3 degrees 30 minutes forward of the hole 1 of plate Sl, the particle
b will be divided into portions dl and fl, with dl remaining within the
5 opening of plate Ml and fl passing on through to the opening of plate S2.
It is assumed in Figure 6 that the reader is looking at a openings within
the ring number 8 containing 103 openings of Figures 7 and 8 disposed 3
degrees and 30 minutes from the first opening of stationary plate Sl. The
particle fl will therefore move ahead under pressure to the abutting edges
10 of the moveable plate M2 which for all intents and purposes, we will
assume happens instantaneously, so that the opening of plate M2
therefore is opening number 3 which is 7 degrees disposed from the
opening of stationary plate Sl. The particle fl is therefore divided into a
remnants f2 and a smaller particle gl which moves on to that opening
15 disposed 7 degrees from the original opening of plate Sl. Again assuming
this happens instantaneously the particle gl will then move ahead to the
stationary plate S3 and the effective shearing of the particle thereat at the
boundary of M2 and S3 so that gl therefore becomes a remnants g2 and a
smaller particle jl contained within the opening S3 which is disposed at
20 10 degrees 30 minutes of the opening of plate Sl. The particle jl will
therefore move onto the boundary of the movable plate M3 whereat the
particle jl will be divided into a remnant j2 which remains in the opening
of plate S3 and in other finely divided particle kl within the opening M3
which is disposed at 14 degrees from the opening of the plate Sl. The
25 particle kl will therefore be reduced to a remnant k2 at the boundary of
plate S4 as described in relation to the previous description so that a
remnant k2 remains within the opening M3 and a small particle n is
contained with the opening S4 (rotation of 17 degrees 30 minutes from
` _ 30 212172~
plate S1). The small remnants S4 will then be carried on through to the
plate M4 and through the stationary plate S5 which will result in two
more cuts over a total of 21 degrees. Therefore in following the particle 1
through comminuter 50 it can be seen how quickly the contaminant
5 material can be divided and appropriately sized through the process.
It must be understood by the reader when referring to Figure
6 that the position of the opening in screen S1 is not in line with the
openings of M1, S2, M2 S3, M3 and S4 at the same time instantaneously.
The purpose of Figure 6 is to illustrate and describe in relation to the
10 illustration the reduction of the particle in a continuous manner with the
openings of each of the various stationary and moveable plates being
offset by predetermined numbers of the degrees as described above.
As a result of the finely divided particle size of the
contaminants, it has been found that a plastic film f a portion of which as
15 seen in Figure 5 can be manufactured with particles much less than 1 mm
or about 39 one thousandths of an inch. With a specification of the grind
size being less than 20 mesh or 50 thousandths of an inch it can readily be
seen that the particles el to el9 will not plug the dies of a film line which
are generally between 65 and 85 thousandths of an inch. Nor will such
20 particles accumulate in one position line but be dispersed throughout the
product so as not to affect unduly the product's qualities. Film has been
manufactured and found to be readily formable into a useful garbage bag
which is quite strong.
Referring now to Figure 9 there is illustrated an alternative
25 embodiment of the comminuting device of the instant invention. In the
case where metal may be carried in the waste product stream it is highly
desirable to provide a relief chamber c1 and c2 within the comminuting
device to ensure that the metal does not bind the comminuting machine.
-31- 212172~
Spacers p5 and p6 therefore are provided to ensure that a proper relief
chamber is provided, the spacers running between the stationary plates S1,
S2 and S3 and thereby provide the relief chambers between the moveable
plate M1 and the stationary plate S1, and the moveable plate M2 and the
5 stationary plate S2. The keys kl and k2 are provided as per Figure 4 and
all other aspects remain identical. Thus the contaminants are
comminuted to provide a result similar to that shown in Figure 6.
Similarly use of the comminuting devices of Figures 4A and 4B will
achieve similar results (provided in Figure 4A sufficient concentric
10 cylinders bearing opens therethrough are used or series of cylinders are
used) and (sufficient serially disposed comminuting devices are used as
shown in Figure 4B).
It is very important when considering a film line that the
process comminutes contaminants so fine that it minimizes the aspect of
15 plugging the film dies which are usually in the range between 65 and 85
thousandths of an inch which if plugged will create a die line if
contaminates were too coarse. If it is determined that the contaminants
which are undesirable are not ground to a fine enough size the RPMS
(revolutions per minute) may be increased on the comminuting device or
20 the process may be slowed down somewhat or both, or the number of
plates may be changed or the diameter of the plates may be changed so
that more cuts are achieved with more holes.
This results in a plastic product therefore manufactured
which includes a matrix of plastic material which has contained therein
25 encapsulated sized undesirable contaminants completely surrounded by
plastics material and so sized so as not to degrade unduly the properties of
the finished plastic product being manufactured such as plastic films,
pales, shovels, containers, plastic pipe or the like whatever product can be
-32- 21~172~
made.
Referring now to Figure 2B, there is illustrated an alternative
arrangement with respect to Figure 2 and Figure 2A. Specifically, it has
been found that engineered plastic products such as bumpers, door panels,
5 headlight housings, tail-light housings, and mirror housings made from
engineered plastics are difficult to recycle, as described in THE
BACKGROUND OF THE INVENTION. Figure 2B describes a system for
recycling engineered plastics, which includes receiving the engineered
plastics at a process 100, in a receiving hopper 101, and the plastic being
10 pre-sized to fit in the hopper and pass through to an incline conveyer 102,
to an inlet 104, of a grinding device 105, to size the received engineered
plastics to a size that could be easily extruded. The material then passes
through the grinder 105, to another hopper 106, up an incline belt 107, to
the extruder 108, and from the end of the extruder 109, the material
extends into a comminuting device 110, at the end 111 thereof, with the
material passing from the comminuting device to atmosphere at a melt
pump 115, to pass the material on a pelletizing system 120. Such
equipment is known in the art. The comminuting device 110 therefore
may be designed as described within this disclosure or any embodiments
20 equivalent thereto. The extruder may be the single or the dual shaft
extruder as described above.
Referring now to figure 4C, there is provided a comminuting
device 110, which has rotating cone-shaped devices P10, rotating against
stationary cone-shaped device P15. As per the previous descriptions, a
25 drive shaft D1 is provided. The main reason in providing the conical
shape is firstly to reduce the overall diameter of the machine because the
conical arrangement provides for more holes or openings than the flat
plates previously described. Therefore, the increased surface area allows
-33- 2121725
for the small diameter of the machine, and, as a result, requires less torque
to drive the plates, and therefore less horsepower, resulting in a more
efficient machine.
Referring now to Figure 4D, there is provided another
5 alternative within the figure of a comminuting machine, illustrated in
Figure D, where the drive shaft D2 supports stationary plates P25 and
Oscillating or reciprocating plates that move up and down with respect to
plates P25. As a result of the provision of a camshaft Cl, having various
cam portions for each of the oscillating plates P20 to allow for the motion
10 thereof and the passage of material and the shearing of the contaminating
particles, progressively through the device.
Referring to Figure 4E, there is described an installation
within the comminuting device similar to that already described in
relation to the plates, wherein the stationary plate P40 and a planetary set
15 P45 is provided, with voids Vl there between wherein a ring gear R40 is
provided which engage with the planetary gears P46 which are connected
to the drive shaft D5 by a Y-shaped connector Yl, thereby providing
rotation of each of the gears P46 in the predetermined direction so as to
allow the multiple cutting surfaces C40 to cut or shear the product or
20 plastic matrix and the contaminating materials to progressively smaller
and smaller size through the comminuting device.
Referring to Figure 4F, there is illustrated a comminuting
device having a number of spring-loaded knives P52 provided within a
stationary drum P60 having openings P61 extending therethrough. The
25 knives therefore rotate on the drive shaft D8. The knives P52 therefore
cut the material as previously described in relation to Figure 6 as the
material passes through the comminuting device. The knives are
supported by a number of drum-shaped devices P70, separated by spacers
-34- 212172~3
P80. The knives are spring-loaded and the material will pass through the
void V5. A Belleville spring may be used to keep the knives tight up
against the drum BVl. As an alternative to Figure 4F, Figure 4G is
presented, which in essence provides for a similar arrangement to Figure
4F with the exception that internal cutting hoops Hl are provided, which
are spring-loaded outwardly to be in contact with the internal drum as is
the case with the rotating knives. The spacers are identical to what is
described in relation to 4F except for the use of the hoops Hl.
Referring now to Figure 10, there is described a combination
extruder-comminuting device 130 having a hopper at one end to receive
the material into the extruder 140 having an outer housing 141 and flights
of conveyer 142 wherein stationary plates 160, 161,162, 163 are provided on
drive shaft 145 and rotating plates 150, 151, 152, 153 operate in a similar
manner to that which is described in Figure 6. Of course, the plates might
be limited by the diameter of the screw, unless the outer housing 141 were
extended to approximate the plates. Also, the plates rotate in relation to
the screws at a constant speed, and therefore there is less control with this
particular embodiment, and although it is not preferred, it is an
alternative.
As many changes can be made to the invention without
departing from the scope of the invention, it is intended that all material
contained herein by interpreted as illustrative of the invention and not in
a limiting sense.
