Note: Descriptions are shown in the official language in which they were submitted.
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Filter tow bale, device and method for producing a filter tow
bale and filter tow strip
The present invention relates to a filter tow bale with the
features of the preamble of claim 1, a device and a method for
producing a filter tow bale and a filter tow strip.
A filter tow bale of the type mentioned at the outset is
produced and marketed, for example, by the Applicant.
To produce cigarettes, filters are used, which are
manufactured from a band or a continuous strand of crimped
cellulose acetate fibres, the so-called filter tow. During
the production of filter tow, spun filaments of cellulose
acetate are crimped in a stuffer box, the impressed crimping
structure being fixed while passing through a dryer. Once the
filter tow has been brought to a constant final moisture, it
is loosely inserted in regular patterns in a plurality of
metre-high cans. The loose tow layer is then compressed in
bale presses to form a filter tow bale and finally packaged,
the bale then being provided for further processing into
filters.
A detailed description of the production process of filter tow
is published in the essay CA Filter Tow fur Cigarette Filter
(CA filter tow for cigarette filters), Paul Rustemeyer,
Macromolecular Symposia 208 (2004), 267 - 291.
Filter tow is processed into filter rods on a filter rod
machine, on which the filter tow is bulked up as much as
possible in a preparation part in order to develop its maximum
filling force and is then gathered together to the format of
the future cigarette filter and covered with paper. To bulk
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up the filter tow, the latter is drawn apart by means of
compressed air-operated spreader nozzles and drawn by a system
of drawing rollers with thread or screw surfaces. Thereafter,
the spread filter tow is fed to a triacetin spray box, in that
the acetate surface has solvent applied to it and is made
tacky. In the formatting part of the filter rod machine, the
filter tow band is gathered together and compressed to the
cross section of the future filter rod. In this case, the
filaments stick together and form a three-dimensional spatial
network structure with the filter hardness desired for further
processing and for the consumer.
To increase productivity, it is known, for example, from DE 43
20 317, which also goes back to the Applicant, to produce
filter rods on double filter rod machines, in which two filter
tow strands are processed in parallel and synchronously.
For a quality of the filter rods, which is as constant as
possible, on the one hand, the filter tow strips should have
similar properties and, on the other hand, run as uniformly as
possible from the filter tow bale and also into the double
filter rod machine.
The invention is based on the object of disclosing a filter
tow bale, which allows a filter tow strip to run off as
uniformly as possible and is suitable for use in a double
filter rod machine. Furthermore, a device and a method for
producing a filter tow bale and a filter tow strip for a
filter tow bale of this type are to be disclosed.
According to the invention, this object is achieved with
regard to the filter tow bale, by the subject of claim 1, with
regard to the device, by the subject of claim 10, with regard
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to the method, by the subject of claim 18, and with regard to
the filter tow strip by the subject of claim 21.
The invention has the advantage that spontaneous tension
increases in the filter tow at the double filter rod machine
are substantially avoided by the separate filter tow strips,
so the density fluctuations connected therewith in the filter
produced are minimised. Moreover, the filter tows may be
produced and deposited simultaneously, so the properties
thereof are similar or identical, which leads to an improved
filter uniformity of the two strands during production on the
double filter rod machine. Moreover, owing to the identical
running lengths of the two filter tows, production drops are
reduced. When there are different filter tow lengths, for
example caused by running off from two different filter tow
bales, increased waste and machine standstill times occur
owing to the process of threading a new filter tow. The bale
according to the invention also allows different filter tows
to be inserted in the bale, so, for example, filter rod
machines for special filters can be supplied with two
different tows.
In a preferred embodiment, the at least two filter tow strips
are heaped chaotically in insertion paths, in particular in
substantially parallel paths or in acute-angled zigzag paths
in the bale. This embodiment is based on the general idea of
arranging the two filter tow strips aligned in the bale, the
two strips forming a path pattern. The path pattern may, for
example, be constructed from substantially parallel paths or
from acute angled zigzag paths. The two filter tow strips are
in each case chaotically heaped up along or within the paths.
This means that in this embodiment, the chaotically heaped
filter tow strips in each case have a preferred direction or a
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dominating direction, which extends path-wise in the bale.
The paths thus in each case form imaginary side limits, within
which the chaotically heaped filter tow strips are arranged.
Because of the path-wise arrangement of the filter tow strips
arranged layer-wise, the run-off behaviour of the strip from
the bale is advantageously influenced.
The two filter tow strips may be arranged substantially in
parallel paths next to one another and have a spacing, which
is at least 0 cm and at most less than half the bale width.
With a spacing of 0 cm, the filter tow strips or the paths,
within which the filter tow strips are arranged, directly abut
one another. The spacing between the parallel paths or the
strips arranged in parallel may be > 0 cm and a maximum of
less than half the bale width. In a particularly preferred
embodiment, at least two filter tow strips are arranged
overlapping at least in portions and have an overlap region.
The overlap region may have a degree of overlapping of 100% to
> 0%. Part regions of this overlap region are also possible.
With a degree of overlapping of 100%, the filter tow strips or
the paths within which the filter tow strips are arranged, lie
completely one above the other.
In this case, the filter tow strips may be deposited in the
bale in such a way that the strips are alternately arranged at
the top and bottom. In this case, the strip arranged at the
bottom in a path has, at the bale end, a turning point
reversal in such a way that the strip firstly arranged at the
bottom is arranged at the top after the turning point reversal
on the return path. This produces a self regulation which
prevents the strips running ahead, as the lower one of the two
strips has a higher tension if it wishes to overtake the upper
strip. Because of the arrangement of the strips one above the
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other, the lower one entrains the upper strip. After the
turning point, when running back, the other strip is at the
top, so the lower strip in turn then has the greater tension
and entrains the strip arranged at the top. Overall, this
produces a self regulation when the two strips run off from
the bale.
Further preferred embodiments of the filter tow bale according
to the invention are disclosed in the sub-claims.
With regard to the device for producing a filter tow bale, the
invention is based on the idea of providing an inserting
device, which cooperates with a can to deposit the filter tow,
as well as means for simultaneously producing or providing at
least two separate filter tow strips. In this case, the
separate filter tow strips can be deposited together layer-
wise in the can by a single or a double inserting device.
Within the scope of the method according to the invention to
produce a filter tow bale, in particular for processing in a
double filter rod machine, at least two separate filter tow
strips are produced or provided simultaneously, deposited
together layer-wise in a can and pressed into bale form.
The filter tow bale according to the invention can easily be
produced with the device according to the invention or the
method according to the invention.
Preferred embodiments of the device according to the invention
or the method according to the invention are given in the sub-
claims.
A filter tow strip, which is particularly suitable for a
filter tow bale according to the invention made of cross-
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linked and crimped filaments, has at least two partial strips,
the partial strips being arranged at least partly, in
particular completely, overlapping and being connected in the
overlap region by applying a mechanical surface force. The
run-off behaviour of the filter tow strip from the bale is
positively influenced by the slight connection between the two
partial strips, which are otherwise regarded as separate
partial strips in the context of the invention.
Preferred embodiments of the invention are given in the sub-
claims.
The invention will be described in more detail below with the
aid of embodiments with reference to the accompanying
schematic drawings, in which
Fig. 1 shows a schematic cross section of two filter
tow strips in various combination possibilities A - E in the
region of the inserter;
Fig. 2 shows a filter tow bale according to the
invention while the filter tow strips run off according to a
preferred embodiment;
Fig. 3 shows a filter tow bale according to the
invention while the filter tow strips run off according to a
further preferred embodiment; and
Fig. 4 shows a schematic view from above of the bale
surface, the insertion track of two filter tow strips arranged
one above the other being shown.
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Fig. 1 schematically shows various variants A - E for
combining two filter tow strips 1, 1', the combination of the
two filter tow strips 1, 1' taking place before or during the
insertion into a can. The filter tow located in the can is
then compressed to form a double tow bale 2.
The combined filter tow strips shown in Fig. 1 are located in
the inserter (not shown), in particular between the conveying
roller of an inserter. This view is selected for reasons of
clarity, as the arrangement of the two filter tow strips 1, 1'
relative to one another becomes particularly clear there. The
arrangement of the two filter tow strips 1, 1' in the inserter
determines the arrangement of the two strips 1, 1' in the
filter tow bale 2. This means that the strips 1, 1' arranged
in parallel in the inserter according to view A are also
arranged substantially parallel or in parallel paths in the
filter tow bale 2. The strips 1, 1' arranged one above the
other according to the view B are also arranged one above the
other in the bale or are deposited in paths arranged one above
the other.
The depositing of the filter tow strips in the can and
therefore the arrangement of the filter strips in the
compressed bale takes place in paths. The paths are arranged
in a predetermined pattern in this case, which is produced
from the arrangement of the filter tow strips 1, 1' in the
inserter and the guidance of the filter tow strips 1, 1' while
being inserted. The filter tow strips 1, 1' are arranged
chaotically heaped within the paths. The paths follow a
predetermined pattern. For example, the paths are arranged in
parallel, completely overlapping or partly overlapping. The
arrangement of the filter tow strips 1, 1' or the associated
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paths will be described in more detail with the aid of
variants A - E according to Fig. 1.
According to variant A in Fig. 1, the two filter tow strips 1,
1' are arranged next to one another at a spacing. The strips
1, 1' are in this case oriented parallel to one another, the
spacing along the two strips 1, 1' remaining substantially
constant. The filter tow strips 1, 1' may have a spacing of 0
cm with respect to one another, so the filter tow strips 1, 1'
touch one another directly. It is also possible for the
spacing between the two filter tow strips 1, 1' to correspond
to half the width of the double tow bale 2, so one half of the
double tow bale 2 is in each case associated with one filter
tow strip 1, 1'. All the spacing values between 0 cm and half
the bale width or less than half the bale width are also
possible, in particular in the range of between 0.5 cm and 20
cm, between 5 cm and 20 cm or between 5 cm and 10 cm.
According to variant B, the two filter tow strips 1, 1' are
combined with one another completely overlapping lengthways.
In this manner, a slight connection is formed over the entire
strip width between the two filter tow strips 1, 1', which
allows a particularly uniform, synchronous running off of the
filter tow strips 1, 1' from the double tow bale 2 according
to the invention. The two filter tow strips 1, 1' may also,
as shown in variant C, be combined partly overlapping one
another, it being possible for the degree of overlapping of
the two filter tow strips 1, 1' to vary between 0% (variant A)
and 100% (variant B). Even if a slight connection is
established by the compression of the strips 1, 1' arranged
one above the other, the strips are regarded as separate
strips 1, 1' in the context of the invention.
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According to a preferred variant D, the two filter tow strips
1, 1' are arranged completely overlapping one another and
folded in half lengthways, so the combined strip is
substantially composed of four filter tow layers. After the
insertion of the combined strip, with this variant, not only
is a slight connection achieved between the two filter tow
strips 1, 1' by compressing the double tow bale 2 according to
the invention, but also a slight connection of the two
longitudinal halves of the first filter tow strip 1 with one
another is achieved. By folding the combined strip, it is
also achieved that a relatively narrow and easily handleable
combined strip is formed from relatively wide filter tow
strips 1, 1' . Variant E also offers this advantage, the two
filter tow strips 1, 1' being folded engaging in one another,
i.e., the first filter tow strip 1 substantially has a degree
of overlapping of 50% with the second filter tow strip 1', the
non-overlapping part of the first filter tow strip 1 being
folded, so the latter rests on the overlapping part of the
second filter tow strip 1', in particular congruently with the
overlap region. The outer, non-overlapping part of the second
filter tow strip 1' is likewise folded, so it comes to rest on
the folded first filter tow strip 1. According to variant E,
the connecting face between the two filter tow strips 1, 1' is
particularly large, so a relatively intensive and nevertheless
easy to release connection is formed between the two filter
tow strips 1, 1' and therefore leads to a particularly
advantageous, uniform and synchronous running off of the
combined strip or the two filter tow strips 1, 1' from the
double tow bale 2 according to the invention.
Figs. 2 and 3 in each case show a double tow bale 2 according
to the invention, the two filter tow strips 1, l' according to
variant A from Fig. 1 being arranged next to one another. A
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bale 2 with strips 1, 1' arranged one above the other or paths
according to variant B would be handled in accordance with
Fig. 2. The spacing of the two filter tow strips 1, 1' in
Fig. 2 is less than half the bale width, while the spacing of
the two filter tow strips 1, 1' in the double tow bale 2
according to Fig. 3 corresponds to precisely half the bale
width.
Furthermore, Figs. 2 and 3 schematically show a run-off device
3 with guiding rings 4, by means of which the first filter tow
strip 1 and the second filter tow strip 1' run off from the
bale 2 and are fed to a double filter rod machine (not shown).
The two filter tow strips 1, 1' are in each case arranged in a
meandering shape in a plane in the double tow bale 2, the
spacing of the two filter tow strips 1, 1' with respect to one
another being substantially constant. The embodiment
according to Fig. 3 differs from Fig. 2 in that one half of
the double tow bale 2 is associated in each case with one
filter tow strip 1, 1'. When inserting the filter tow strips
1, 1' in the bale 2, for example, the first filter tow strip
1, beginning in the centre of the bale 2, is inserted in a
meandering shape in the direction of an outer edge in parallel
paths, while the second filter tow strip 1', beginning from an
opposing outer edge, is inserted parallel to the first filter
tow strip 1 in a meandering shape in the direction of the
centre of the double tow bale 2. This means, that the two
paths placed first have a spacing from one another, which
corresponds to half the bale width. As the two filter tow
strips 1, 1' are arranged parallel to one another, the further
respectively corresponding parallel paths are also spaced
apart from one another by the amount of half the bale width.
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In general, a filter tow bale 2 made of compressed filter tow
comprises at least two separate filter tow strips 1, 1', which
are arranged layer-wise, preferably in the same layer. A
filter tow bale with precisely two filter tow strips is also
called a double tow bale. In general, the strips are in each
case arranged together, in particular pairwise, in a layer and
together form a plane. In this case, the area is regarded as
a plane, which in the course of a laying cycle of the filter
tow or the associated inserter, is passed over once. Within
this plane it is possible, because of the heaping of the
individual filter tow strips, for there to be a piling up of a
plurality of filter tow portions one above the other, which,
however, continue to lie in the plane passed over for each
laying cycle.
The filter tow bale is built up of a plurality of
corresponding layers or planes arranged one above the other,
which are in each case formed by depositing the two filter tow
strips together in a can with subsequent compression of the
strips. In this case, the strips are configured continuously
over a plurality of layers, ideally over the entire bale. The
filter tow strips are arranged according to a predetermined
pattern, which may vary according to the processing demands.
The pattern is produced form the arrangement of the paths, in
which the filter tow strips are deposited in the can and are
also found again in the bale 2 after compression. The paths,
in this case, correspond to the preferred directions of the
filter tow strips, which are deposited within the paths heaped
chaotically or statistically rearranged. An example of a
corresponding heaping track is shown in Fig. 4. It can be
seen in this that two filter tow strips 1, 1' (dotted
line/continuous line) are substantially arranged one above the
other. The arrangement of the filter tow strips 1, 1' one
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above the other does not mean that the two heaping tracks are
arranged precisely one above the other. Rather, when
depositing the two filter tow strips 1, 1', the heaping track
shown in Fig. 4 is produced, the two filter tow strips 1, 1'
having a common preferred direction. The insertion paths
being produced from this preferred direction are arranged one
above the other in the example according to Fig. 4 and have a
degree of overlapping of 100%. With lower degrees of
overlapping, for example with a degree of overlapping of 50%,
the two paths, within which the heaping tracks of the two
strips 1, l' are arranged, are offset with respect to one
another in such a way that the heaping tracks substantially
only overlap by half. It is clear that in the statistically
rearranged heaps, larger or smaller degrees of overlapping are
present in sections. However, it is important that, for
example with the degree of overlapping of 50%, the heaping
tracks or paths at least predominantly extend such that they
are located approximately half one above the other.
The arrangement of the paths or heaping tracks in the bale is
substantially determined by how the filter tow strips 1, 1'
are arranged in the inserter, in particular in the rollers of
the inserter. This arrangement is shown in variants A - E
according to Fig. 1. For example, in variant C (approximately
50% degree of overlapping) a corresponding arrangement of the
heaping tracks or paths is produced in the compressed bale.
Apart from the parallel arrangement of the paths (overlapping
or next to one another), it is also possible to arrange the
paths to be diverging in such a way that the paths run apart
from one another along their longitudinal extent. Moreover,
an acute-angled zigzag arrangement is possible of the
insertion paths.
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The invention also comprises bales with more than two separate
filter tow strips, for example with 3 or 4 strips. The
parallel arrangement of the filter tow strips 1, 1' means that
the paths, in which the filter tow strips 1, 1' are arranged,
are arranged, in each case, directly adjacent pairwise or
directly next to one another in the bale. The paths of the
first and second filter tow strip 1, 1' may be arranged
overlapping, directly adjacent, i.e. abutting or parallel with
a spacing from one another, in this case. Preferably, the two
filter tow strips 1, 1' are inserted in the bale 2 arranged
overlapping, so they undergo a slight connection.
There are various possibilities for the simultaneous
production or provision of the separate strips. It is
possible to produce various independent strips in various
independent crimping machines. Furthermore, various
independent strips may be produced within a single crimping
machine, the filter tow strips being guided in the crimping
chamber at a spacing which is so great that a connection of
the strips does not take place. Furthermore, a connected
strip may be produced, which is then separated into two
individual strips. For this, various possibilities exist.
The separation of the strip can either take place in the
crimping machine, after the crimping machine, on the way to
the inserting device or in the inserting device. Since the
separation of the strip does not take place in the filter rod
machine, the soiling of the filter rod machine by the fibre
fractions being produced during the separation is avoided, so
maintenance intervals of the filter rod machine can also be
increased.
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The simultaneously produced separate filter tow strips are
deposited combined in the can by a single and a double,
generally multiple inserting device (not shown). The
inserting device is coupled for this purpose to a
correspondingly programmed controller. The controller of the
inserter allows the two filter tow strips to be deposited in
the can in accordance with a predetermined pattern, for
example in paths arranged one above the other.
The device for producing a filter tow bale, in addition to the
above-described means for simultaneous production, also
comprises a spinning mechanism for producing filaments, a
crimping mechanism for crimping the filaments, a drier and the
inserting device, which cooperates with the can for depositing
the filter tow.
The separating device may comprise two guide rings arranged
spaced apart transversely to the conveying direction of the
filter tow strip and a guiding ring arranged upstream of the
guide rings in the conveying direction. Alternatively or
additionally, the separating device may comprise at least one
separating wedge.
Instead of the simultaneous or synchronous production of the
separate filter tow strips 1, 1', a can may be loaded with two
separate filter tow strips, which are provided in the form of
two individual bales. Individual bales may, for example, be
provided in the form of reject bales. Two strips are drawn
off from the individual bales and together placed in a can.
It becomes clear from the above description that the separate
filter tow strips 1, l' can be produced in a different manner,
no restriction existing with regard to the number of filter
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tow strips, but more than two, for example three or four
filter tow strips may be produced or provided. The particular
advantages of the embodiments according to the invention
emerge from the fact that the filter tow strips 1, 1' are
deposited together layer-wise in the can and compressed to
form bales. These filter tow bales have at least two separate
filter tow strips, which are arranged together layer-wise in
the bale.
The insertion of the filter tow strips in the double tow bale
such that the filter tow strips overlap furthermore offers the
advantage that the filter tow strips undergo a slight
connection with one another, which is brought about by
compression, i.e. by the application of mechanical pressure.
It has been shown that a loose connection of this type between
the filter tow strips allows the strips to run off
particularly uniformly and synchronously from the bale, so
density fluctuations in the filter strand produced are
avoided. To this extent, a filter tow strip connected from
partial strips is also claimed, the relatively low strength of
the connection being determined by the fact that the latter is
produced by applying mechanical pressure to the partial
strips, in particular during the compression of the bale.
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List of reference numerals
1 first filter tow strip
if second filter tow strip
2 double tow bale
3 run-off device
4 guiding rings
