Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR THE SEPARATION OF A MATERIAL
MIXTUR~ AND US~ OF THE APPARATUS
Technical Field
The invention is directed to a method, an apparatus and
the use of the apparatu~ for the environmentally sound
separation of a material mixture, e.g. a mixture of
reclaimable material (recyclables), into individual material
components of different character, wherein the material
mixture is continuously fed to a rotating, inwardly elastic
sorting drum.
Backaround Art
In the environmentally sound processing e.g. of
recyclable material mixtures, container waste, and
components similar to household waste, the problem arises of
separating specific categories of recyclable materials as
completely as possible. Both the sieving technique and the
air separation technique are limited. Since organic, highly
adhesive components or fine dust components also often occur
in the aforementioned recyclables, separation by air or
sieves involves corresponding disadvantages.
In individual cases it is unavoidable that vastly
different collected material, e.g. liftings, are to be
æorted into easily reclaimable organic components and heavy
fractions intended for recyclables or dumps.
In recent times, repeated efforts have been made for a
recycling which is as complete as possible, at least with
glass receptacles, cans, aluminum cans, plastic bottles,
etc. The newly developing flow of material must be
separated in an efficient manner, so that the individual
base materials such as glass and aluminum can be returned to
other respective processing centers at a minimum of expense.
In the case of glass, it is required that there be as little
glass breakage as possible. This rules out an excessively
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large massing. The consequence of this would be many small
plants, if possible in the vicinity of the consumers.
The current practice is sorting into different
categories of material by hand. A typical characteristic of
all highly industrialized societies is the high cost for all
manual labor. The required high expenditure on manual labor
often stands in the way of the complete success of a genuine
recycling.
A solution is known in US-PS 4,760,925 in which the
mixture is separated into a heavy fraction and a light
fraction by means of a brush shaft following a pre-
separation by means of a slope conveyor belt. In this
patent, heavy parts fall down directly without being
influenced by the brush movement. Tests conducted by the
present Applicant showed only an insufficient or fluctuating
separation quality when the product was conveyed, as it
were, frontally to the sorting drum, and the heavy fraction
is sorted out opposite the movement direction of the sorting
drum and the lighter fraction is lifted over around the drum
radius and thrown to the other side of the drum.
Disclosure of Invention
The object of the invention is to achieve a powerful
separating effect for different kinds of material mixtures
with the use of simple, inexpensive operating means and the
corresponding methodology, respectively. Moreover, as
little energy as possible is to be used for operation, and
it should be possible for a small number of trained
personnel to operate.
The method, according to the invention, is
characterized in that the material mixture is guided to the
sorting drum in the same direction as the surface movement
and divided into fractions in the movement direction of the
sorting drum.
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To the surprise of all participants knowledgeable in
the field, it was possible to achieve an unexpectedly
excellent sorting quality already with a first, very ~imply
conceived test device. For example, it was possible after a
few test runs to divide a mixture of glass bottles and
plastic and aluminum cans, as occur in corresponding U.S.
collection locations, into glass and remaining components
with an accuracy of almost 100%. A centrifugal drum brush,
as is known in car washing installations, was used for the
test. The energy requirement for the sorting amounts to
only a low percentage of that of systems utilizing the air
sorting solution. When observing the test for the first
time, the observer did not even immediately grasp why,
without an immediately visibly detectable cause, the glass
bottle sank in the rotating direction of the sorting drum
and was discharged at the bottom, but the plastic bottles
were rejected with complete accuracy and thrown into an
adjoining collecting container or onto a corresponding
discharging element, respectively. The present invention
showed for the first time that the parameter of area
pressure allows a new excellent sorting technique for many
sorting problems, particularly with bodies which do not have
a determined shape from the beginning, when the heavy bodies
sink substantially radially and not tangentially. The
weight, per se, and the size still only play a secondary
role for the genuine area pressing sorting technique. The
success of the sorting is due chiefly to the area pressure
and the corresponding centrifugal penetration-inhibiting
force dynamic produced by the rotation of the sorting drum,
respectively, on the one hand, and the dynamic interplay
between the bristles and the bodies to be sorted on the
other hand. The separation of the mixture components is to
occur on the throw-off side in the ejecting direction of the
bristles of the centrifugal drum, since it is only in this
manner that the plurality of bristles are compelled to
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interact with each particle of the mixture in a genuinely
selective manner so as to exert separating force. The
actual separation is effected between light and heavy bodies
with respect to specific area pressure.
In another test, a material mixture which was pre-
sorted through a sieve as liftings had to be divided into a
mechanical fraction and an organic fraction. A surprisingly
good separating quality was also achieved in this case,
particularly when the material mixture previously only
contained portions which were e.g. smaller than a foot, e.g.
smaller than 250 to 300 mm.
The invention allows different particularly preferred
embodiment ideas.
In an especially preferred manner, the sorting drum is
constructed as a centrifugal drum brush and the elasticity
or impressibility of the sorting drum and the area pressure
resulting from this, respectively, is determined by
corresponding selection of the speed and/or the outfitting
of the sorting drum (with bristles). The largest possible
body which can be separated out is determined by the length
of the bristles.
In addition, the raw material is preferably fed
continuously to the cylindrical outer surface area of a
sorting drum by a feed unit. It is suggested that the raw
material be fed in the area on the sorting drum loca~ed at
the top, especially preferably in the highest area.
Depending on the material mixture, the sorting quality
is increased in that the material to be separated is
delivered with more tangential components with respect to
the sortinq drum or with more radial components. The
previous tests have shown that the raw material on the feed
unit is to be pre-accelerated to approximately 10 to 30%,
preferably 10 to 25%, of the circumferential speed of the
sorting drum.
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In addition, it is known that the sorting drum produces
a strong air current which can be directed. This can be
utilized for the separation of an additional light fraction
such as paper pieces, threads, strings, etc. At the same
time, the air current prevents strings and the like from
winding around the sorting drum in a highly reliable manner,
so that a very high operating reliability can be achieved.
The invention further concerns an apparatus for the
separation of a material mixture into individual material
components as previously described. The apparatus,
according to the invention, is characterized in that it
comprises a feed device for the continuous delivery of the
material mixture into an upper sector, preferably
corresponding to 11 o'clock to 2 o'clock, but particularly
preferably between 12 and 1 o'clock, (as seen in cross
section) in the direction of the surface movement of the
sorting drum. A light portion discharge is preferably
arranged on the throw-off side approximately at the height
of the rotational axis of the drum and a heavy portion
discharge is preferably arranged in the lower adjacent
quadrant. The sorting drum is preferably constructed as a
centrifugal drum brush; e.g. in the event that a washing
brush for car washing systems is used the drum effect first
develops in the operating state. When stopped, the bristles
hang down. The resistance behavior for the penetration of
bodies into the interior of the sorting drum is determined
by means of the centrifugal force occurring during rotation
and by means of the selection of the quantity and the
quality of the bristles. The rejecting force of every
rotating brush and the air current whi~h is adjusted produce
the impulse for the rejection of the parts which are lighter
with respect to specific area pressure.
It is particularly preferred that the material mixture
feed means be constructed as a belt or acceleration belt,
especially preferably with a sieve connected prior to it or
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as a rod chain grate conveyor or as a stationary sieve,
particularly as a bar sieve.
It is further suggested that the conveying speed of the
feed device be 0.5 to 2 m/sec, preferably 1.2 to 1.5 m/sec,
and that the circumferential speed of the drum be 5 to 15
m/sec, preferably 7 to 10 m/sec, at a diameter of 1 to 1.5
m.
The invention is further directed to the use of a
centrifugal drum brush for the sorting material mixtures
such as container waste, e.g. mixed construction site
refuse, road excavation refuse, construction material
remains and collection material similar to household waste,
which are preferably pre-sorted via sieves, wherein the
heavy fraction substantially contains mineral components and
the light fraction substantially contains the organic
materials.
Brief Description of the Invention
The invention is now explained in more detail with the
aid of three embodiment examples.
Fig. 1 shows a first embodiment example in a schematic
manner;
Fig. 2 shows an embodiment form for container waste in a
schematic manner;
Fig. 3 shows an e~bodiment example for the additional
suction of a light fraction such as foils, paper, etc.
Best Mode for Carrying Out the Invention
Reference is now made to Fig. 1. The material mixture
- 11 is transferred directly to a sorting drum 2 via a feed
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device 1. The sorting drum 2 is driven via a shaft 3.
Bristles 4 which are put into a cylindrical shape S by means
of the rotation of the shaft 3 and the acting centrifugal
force, respectively, are fastened at the shaft 3. Due to a
much higher area pressure, glass bottles 6 sink into the
interior of the drum as shown with bottles 6' and 6". The
bottle 6'' i5 transferred to a discharge belt 7 for heavy
material 15 below the sorting drum 1 and fed to a
corresponding collector. Bodies, such as aluminum cans and
plastic bottles~ which exert only a slight area pressure
when impacting on the sorting drum 2, are thrown off
tangentially from the drum surface by the bristles 4 when
impacting on the latter (see aluminum can 8, 8' and 8",
respectively, and plastic bottle 9, 9'). The latter are
transferred to a collector for medium material 16 via a
second discharge belt 10.
The material mixture 11 is divided into three fractions
according to Fig. 1. The heavy material 15 contains all
bodies exerting a large area pressure on the sorting drum 2,
such as glass bottles, solid metal bodies or e.g. heavy
stones in the material mixture would also be sorted out with
the heavy fraction 15. The medium material 16 contains all
light hollow bodies such as aluminum cans and plastic
bottles. Iron cans can be sorted out by means of magnet
separators, either before or after the sorting drum.
Any fine component in the material mixture,
particularly also broken glass, is sieved out prior to the
sorting drum 2 by means of a feed device 1 constructed as a
rod chain grate conveyor 12 and fed to a collector for fine
material 17 via a funnel 13 and a belt conveyor 14.
Fig. 2 shows, in a schematic manner, a sorting device
for container waste with components similar to household
waste. A pre-grading of the raw material mixture is
important in container waste. The raw material mixture is
transferred continuously via a feed belt 20 to a sieving
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system or a sieving stage 21. An upper or preliminary
coarse sieve 22 removes all parts e.g. larger than the size
of a foot, e.g. larger than 250 to 350 mm, e.g. large pieces
of stone, larger pieces of wood, etc. The tailings of the
coarse sieve 22 are separated out as coarse material 23
directly via a belt 24. Fine material 17 falls through the
coarse sieve 22 as well as through a fine sieve 25 arranged
under the latter and is discharged via a funnel 13 and a
belt conveyor 14.
The medium fraction of the raw material mixture is
transferred to an acceleration belt 26 as tailings of the
sieving stage 21. Depending on the case of application, the
acceleration belt 26 is provided with an adjustable drive
motor, not shown, so that the conveying speed of the
material mixture can be specifically selected in the area
where it impacts on the sorting drum 2. The acceleration
belt 26, which can be operated regardless of the prior
processing, offers in every event the possibility of a
defined feeding of the material mixture to the sorting drum
2. It is also possible to arrange additional aligning means
in the acceleration belt 26, so that at least the parts
which are difficult to sort impact on the sorting drum 2 in
the optimal direction and position. Stones and the like, as
heavy material 15 with a large area pressure, sink into the
sorting drum 2 and are carried off in a downward direction
via the discharge belt 7. Medium material 16, which
contains predominantly organic components, is discharged via
the discharge belt 10.
Fig. 3 shows another embodiment idea. In contrast to
Figures 1 and 2, light material 30, e.g. paper pieces, very
small pieces of plastic and the like, are additionally
sucked away via an aspirator 31 according to Fig. 3.
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