U.S. patent application number 12/809976 was filed with the patent office on 2010-12-02 for filter tow bale, method and device for producing a filter tow bale and filter tow strips.
This patent application is currently assigned to Rhodia Acetow GMBH. Invention is credited to Paul Rustemeyer.
Application Number | 20100300468 12/809976 |
Document ID | / |
Family ID | 40451081 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100300468 |
Kind Code |
A1 |
Rustemeyer; Paul |
December 2, 2010 |
FILTER TOW BALE, METHOD AND DEVICE FOR PRODUCING A FILTER TOW BALE
AND FILTER TOW STRIPS
Abstract
The invention relates to a filter tow bale (2) from compressed
filter tow, which is characterized in that the filter tow bale (2)
comprises at least two separate filter tow strips (1, 1') that are
arranged together in layers.
Inventors: |
Rustemeyer; Paul;
(Gundelfingen, DE) |
Correspondence
Address: |
Leason Ellis LLP
81 Main Street, Suite 503
White Plains
NY
10601
US
|
Assignee: |
Rhodia Acetow GMBH
Freiburg
DE
|
Family ID: |
40451081 |
Appl. No.: |
12/809976 |
Filed: |
December 4, 2008 |
PCT Filed: |
December 4, 2008 |
PCT NO: |
PCT/EP2008/010296 |
371 Date: |
August 5, 2010 |
Current U.S.
Class: |
131/331 ;
493/42 |
Current CPC
Class: |
A24D 3/0204 20130101;
B65H 45/20 20130101; B65H 45/08 20130101; A24D 3/02 20130101; B65H
2801/54 20130101; B65H 54/78 20130101; B65H 45/24 20130101 |
Class at
Publication: |
131/331 ;
493/42 |
International
Class: |
A24D 3/06 20060101
A24D003/06; A24D 3/02 20060101 A24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2007 |
DE |
102007061933.4 |
Claims
1. A filter tow bale made of compressed filter tow, wherein
characterised in that the filter tow bale comprises at least two
separate filter tow strips which are arranged layer-wise.
2. A filter tow bale according to claim 1, wherein the at least two
filter tow strips are arranged in the bale chaotically and are
heaped in paths.
3. A filter tow bale according to claim 1, wherein two filter tow
strips in the filter tow bale are 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.
4. A filter tow bale according to claim 1, wherein the at least two
filter tow strips are arranged overlapping at least in portions and
have an overlap region.
5. A filter tow bale according to claim 4, wherein the overlap
region has a degree of overlapping of 90% to 10%.
6. A filter tow bale according to claim 1, wherein the filter tow
strips are folded into one another and in each case have a fold
edge.
7. A filter tow bale according to claim 6, wherein the fold edges
are substantially arranged one above the other.
8. A filter tow bale according to claim 6, wherein the fold edges
are arranged substantially opposing.
9. A filter tow bale according to claim 6, wherein the fold edge of
one filter tow strip in each case encloses the longitudinal edge of
the other filter tow strip.
10. A device for producing a filter tow bale from a filter tow,
comprising: a can for depositing the filter tow; an inserting
device which cooperates with the can; means for simultaneously
producing at least two separate filter tow strips together,
layer-wise, in the can.
11. A device according to claim 10, wherein means for
simultaneously producing at least two filter tow strips comprises a
plurality of spinning machines or a multiple spinning machine.
12. A device according to claim 10, wherein the means for
simultaneously producing at least two filter tow strips comprises a
plurality of crimping machines or a multiple crimping machine which
is loaded with two separate filter tow strips.
13. A device according to claim 12, wherein the means for
simultaneously producing at least two filter tow strips further
comprises at least one separating device for separating the filter
tow strips which is arranged downstream of the crimping
machine.
14. A device according to claim 13, wherein the separating device
comprises at least two guide rings arranged spaced apart and
transverse to a conveying direction of the filter tow strip.
15. A device according to claim 14, wherein a guiding ring is
arranged upstream of the two guide rings in the conveying
direction.
16. A device according to claim 13, wherein the separating device
comprises at least one separating wedge arranged downstream of the
crimping machine.
17. A device according to claim 13, wherein the inserting device
comprises means for depositing the at least two filter tow strips
together in the can.
18. A method for producing a filter tow bale in a double filter rod
machine, comprising the steps of: producing in which at least two
separate filter tow strips simultaneously; depositing the at least
two separate filter tow strips together, layer-wise, in a can; and
pressing the deposited filter tow strips into a bale form.
19. A method according to claim 18, wherein the depositing step
comprises depositing the filter tow strips in an overlapping manner
at least in portions in the can.
20. A method according to claim 18, wherein the producing step
comprises separating a common filter tow strip, the separating
taking place in or after action by a crimping machine or before or
during the step of depositing the at least two separate filter tow
strips in the can.
21. A filter tow strip made of cross-linked and crimped filaments,
comprising at least two partial strips, arranged at least partly,
in an overlapping manner and connected in an overlap region by a
mechanical surface force.
22. A device for producing a filter tow bale from a filter tow,
comprising: A can for depositing the filter tow; an inserting
device which cooperates with the can; means for providing at least
two separate filter tow strips together, layer-wise, in the can.
Description
[0001] 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.
[0002] A filter tow bale of the type mentioned at the outset is
produced and marketed, for example, by the Applicant.
[0003] 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.
[0004] 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.
[0005] 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 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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 to
the method, by the subject of claim 18, and with regard to the
filter tow strip by the subject of claim 21.
[0010] 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.
[0011] 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 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.
[0012] 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.
[0013] 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 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.
[0014] Further preferred embodiments of the filter tow bale
according to the invention are disclosed in the sub-claims.
[0015] 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.
[0016] 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.
[0017] Preferred embodiments of the device according to the
invention or the method according to the invention are given in the
sub-claims.
[0018] A filter tow strip, which is particularly suitable for a
filter tow bale according to the invention made of cross-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.
[0019] Preferred embodiments of the invention are given in the
sub-claims.
[0020] The invention will be described in more detail below with
the aid of embodiments with reference to the accompanying schematic
drawings, in which
[0021] FIG. 1 shows a schematic cross section of two filter tow
strips in various combination possibilities A-E in the region of
the inserter;
[0022] FIG. 2 shows a filter tow bale according to the invention
while the filter tow strips run off according to a preferred
embodiment;
[0023] 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
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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 paths will be described in more detail with the aid of
variants A-E according to FIG. 1.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] FIGS. 2 and 3 in each case show a double tow bale 2
according to the invention, the two filter tow strips 1, 1'
according to variant A from FIG. 1 being arranged next to one
another. A 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.
[0032] 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.
[0033] 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.
[0034] 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 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, 1' 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] It becomes clear from the above description that the
separate filter tow strips 1, 1' can be produced in a different
manner, no restriction existing with regard to the number of filter
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.
[0045] 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.
LIST OF REFERENCE NUMERALS
[0046] 1 first filter tow strip [0047] 1' second filter tow strip
[0048] 2 double tow bale [0049] 3 run-off device [0050] 4 guiding
rings
* * * * *