U.S. patent application number 14/369321 was filed with the patent office on 2014-12-11 for apparatus and method for supplying a continuous web of crimped sheet material.
The applicant listed for this patent is PHILIP MORRIS PRODUCTS S.A.. Invention is credited to Alessandra Contri, Diego Ferrazzin, Michele Pagnoni, Daniele Sanna.
Application Number | 20140364291 14/369321 |
Document ID | / |
Family ID | 47563393 |
Filed Date | 2014-12-11 |
United States Patent
Application |
20140364291 |
Kind Code |
A1 |
Ferrazzin; Diego ; et
al. |
December 11, 2014 |
APPARATUS AND METHOD FOR SUPPLYING A CONTINUOUS WEB OF CRIMPED
SHEET MATERIAL
Abstract
An apparatus for supplying a continuous web of crimped sheet
material to a rod forming device comprises:--a winding unit (3) for
unwinding the sheet material from a bobbin (21) on which the sheet
material is provided,--a crimping unit (7) for crimping the sheet
material,--a dispensing unit (8) for adding a particulate or liquid
add-on material to the sheet material, and--a control unit (9) for
controlling the various units of the apparatus in response to
sensor signals received from the respective units. The dispensing
unit (8) is arranged downstream of the crimping unit (7) when
viewed in the direction of transport of the sheet material, and
upstream of the rod forming device to which the crimped sheet
material is supplied.
Inventors: |
Ferrazzin; Diego; (Modena,
IT) ; Pagnoni; Michele; (San Giovann in Persiceto,
IT) ; Sanna; Daniele; (Bologna, IT) ; Contri;
Alessandra; (Bologna, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHILIP MORRIS PRODUCTS S.A. |
Neuchatel |
|
CH |
|
|
Family ID: |
47563393 |
Appl. No.: |
14/369321 |
Filed: |
December 27, 2012 |
PCT Filed: |
December 27, 2012 |
PCT NO: |
PCT/EP2012/076993 |
371 Date: |
June 27, 2014 |
Current U.S.
Class: |
493/4 ; 493/45;
493/49; 493/50 |
Current CPC
Class: |
A24D 3/0254 20130101;
A24D 3/0295 20130101; A24D 3/0241 20130101; A24D 3/0208 20130101;
A24D 3/0245 20130101; A24D 3/0204 20130101; A24D 3/0212
20130101 |
Class at
Publication: |
493/4 ; 493/45;
493/49; 493/50 |
International
Class: |
A24D 3/02 20060101
A24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 30, 2011 |
EP |
11196246.0 |
Claims
1. Apparatus for supplying a continuous web of crimped sheet
material to a rod forming device, the apparatus comprising a
winding unit for unwinding the sheet material from a bobbin on
which the sheet material is provided; a crimping unit for crimping
the sheet material, a dispensing unit for adding a particulate or
liquid add-on material to the sheet material; and a control unit
for controlling the various units of the apparatus in response to
sensor signals received from the respective units, wherein the
dispensing unit is arranged downstream of the crimping unit when
viewed in the direction of transport of the sheet material, and
upstream of the rod forming device to which the crimped sheet
material is supplied, wherein an amount of particulate or liquid
add-on material to be dispensed by the dispensing unit is
controlled for controlling a resistance to draw of a filter.
2. Apparatus according to claim 1, wherein the crimping unit
comprises a first pair of crimping rollers for engaging and
crimping the continuous web of sheet material being transported
between them, the crimping rollers having a surface adapted to
crimp the sheet material in the direction of transport of the sheet
material.
3. Apparatus according to claim 1, wherein the crimping unit
comprises a second pair of crimping rollers for engaging and
crimping the continuous web of sheet material being transported
between them, the crimping rollers having a surface adapted to
crimp the sheet material in a direction transverse to the direction
of transport of the sheet material.
4. Apparatus according to claim 2, wherein the crimping unit
comprises both the first pair of crimping rollers having a surface
adapted to crimp the sheet material in a longitudinal direction
relative to the direction of transport of the sheet material, and a
second pair of crimping rollers having a surface adapted to crimp
the sheet material in a direction transverse to the direction of
transport of the sheet material.
5. Apparatus according to claim 1, further comprising a cutting
unit for cutting the continuous web of sheet material to a
predetermined width, the cutting unit being arranged upstream of
the crimping unit when viewed in the direction of transport of the
sheet material.
6. Apparatus according to claim 1, wherein the winding unit
comprises a motor for driving the bobbin on which the sheet
material is provided and a brake, the control unit controlling the
motor and the brake in a manner such as to prevent the continuous
web of sheet material from rupturing.
7. Apparatus according to claim 1, further comprising a tensioning
unit comprising a controlled actuator for applying and maintaining
a predetermined tension to the sheet material during the transport
of the sheet material through the apparatus.
8. Apparatus according to claim 1, further comprising a softening
unit for softening the sheet material to be crimped, the softening
unit being arranged upstream of the crimping unit when viewed in
the direction of transport of the sheet material.
9. Apparatus according to claim 1, wherein the sheet material is
one of paper, plastic, metal or is a laminate of at least two of
paper, plastic and metal.
10. Method for supplying a continuous web of crimped sheet material
to a rod forming device, the method comprising the steps of
unwinding the sheet material from a bobbin on which the sheet
material is stored; transporting the sheet material to a crimping
unit; crimping the sheet material; adding a particulate or liquid
add-on material to the sheet material; controlling a resistance to
draw of a filter; and supplying the crimped sheet material to the
rod forming device, wherein adding the add-on material to the sheet
material is performed after crimping of the sheet material and
prior to supplying the crimped sheet material to the rod forming
device.
11. Method according to claim 10, wherein the step of adding a
particulate or liquid material comprises adding carbon particles or
flavoring liquid.
12. Method according to claim 10, further comprising the step of
cutting the sheet material to a predetermined width, wherein
cutting the sheet material to a predetermined width is performed
prior to crimping the sheet material.
13. (canceled)
14. Method according to claim 10, wherein the step of controlling a
resistance to draw of a filter comprises at least one of
controlling an amount of particulate or liquid add-on material
added to the sheet material and controlling a width of the sheet
material.
15. Method according to claim 11, wherein the step of controlling a
resistance to draw of a filter comprises at least one of
controlling an amount of particulate or liquid add-on material
added to the sheet material and controlling a width of the sheet
material.
16. Method according to claim 12, wherein the step of controlling a
resistance to draw of a filter comprises at least one of
controlling an amount of particulate or liquid add-on material
added to the sheet material and controlling a width of the sheet
material.
17. Apparatus according to claim 3, wherein the crimping unit
comprises both a first pair of crimping rollers having a surface
adapted to crimp the sheet material in a longitudinal direction
relative to the direction of transport of the sheet material, and
the second pair of crimping rollers having a surface adapted to
crimp the sheet material in a direction transverse to the direction
of transport of the sheet material.
18. Method according to claim 11, further comprising the step of
cutting the sheet material to a predetermined width, wherein
cutting the sheet material to a predetermined width is performed
prior to crimping the sheet material.
19. Method according to claim 10, further comprising the step of
incorporating the filter into a smoking article.
Description
The present invention relates to an apparatus and method for
supplying a continuous web of crimped sheet material.
[0001] An apparatus of this type is known, for example, in the
field of production of filters for smoking articles such as
cigarettes. These filters are typically made either from cellulose
acetate tow or from a crimped sheet material, for example from
paper. The crimped paper is supplied to a filter making device in
form of a continuous web. The filter making device forms a filter
rod from the continuous web of crimped paper supplied to the filter
making device, and subsequently cuts the filter rod into discrete
filters of a predetermined length.
[0002] An apparatus for supplying a continuous web of crimped paper
to a filter making device is known. In the prior art apparatus, the
outlet of the crimping unit is arranged so as to directly feed the
crimped paper to the filter making device. A control unit controls
the various units of the apparatus and its operation, allowing
little flexibility for variation, e.g. with respect to manufacture
of different types of filters.
[0003] It would be desirable to provide an apparatus which provides
for enhanced flexibility with respect to various types and
properties of filters that can be made using the crimped sheet
material supplied by the apparatus. This would provide enhanced
productivity and cost efficiency for meeting a variety of consumer
needs.
[0004] In one aspect, the present invention provides an apparatus
for supplying a continuous web of crimped sheet material to a rod
forming device. The apparatus comprises a winding unit for
unwinding the sheet material from a support on which the sheet
material is provided, such as a bobbin, and a crimping unit for
crimping the sheet material. The apparatus further comprises a
dispensing unit for adding a particulate or liquid add-on material
to the sheet material, and a control unit for controlling the
various units of the apparatus in response to sensor signals
received from the respective units.
[0005] The dispensing unit is arranged downstream of the crimping
unit when viewed in the direction of transport of the sheet
material, and upstream of a rod forming device to which the crimped
sheet material is supplied. Thus, particulate or liquid add-on
material can be added to the crimped sheet material before the
crimped sheet material is supplied to a rod forming device, for
example to a filter making device. Alternatively, the rod forming
device may be comprised in the apparatus according to the
invention.
[0006] Adding the add-on material after crimping is advantageous.
For example, because the add-on material is added to the already
crimped sheet material, the add-on material or at least a
substantial amount thereof is retained in or on the crimped
structures of the sheet material. The crimped sheet material with
the add-on material is subsequently supplied to the rod forming
device where a rod of filter material is formed which is then cut
to size to form the individual filters having a predetermined
length. Preferably, the dispensing device is arranged directly
upstream of the rod forming device. Thereby, no loss of for example
particulate material or altering of a liquid sprayed on the sheet
material has to be considered, since the sheet material is supplied
to the rod forming device directly after the add-on material has
been added.
[0007] The term "sheet material" in this respect is meant to
comprise any flat web of a material suitable for the production of
filters for smoking articles, such as for example paper or plastic
films. The sheet material can be either a single-layer sheet
material or can be a multi-layer sheet material.
[0008] The term "particulate or liquid add-on material" includes
liquids, but for example also gel-like or pasty materials, as well
as particulate materials comprising, for example, discrete
particles, such as bulk material, powder, granules or the like, and
objects suitable for inclusion into a cigarette filter, such as
capsules or beads. Preferably, the add-on material is a particulate
material.
[0009] The addition of particulate or liquid add-on material to the
crimped sheet material may generally serve various purposes. For
example, it may serve the purpose of adding to the smoke drawn in
by a consumer through the filter. For example, the add-on material
may comprise menthol, tobacco or other desired flavors.
Alternatively or in addition, the add-on material may serve to
remove or alter at least part of the gaseous or solid constituents
of the smoke. For example, the added particulate material may
comprise activated carbon granules.
[0010] Also, the resistance to draw of the final filter can be
varied by adding the add-on material. For example, by variation of
the amount of add-on material, for example particulate material,
added to the sheet material per unit of sheet material the
resistance to draw can be lowered or raised. Preferably, the liquid
add-on material does not influence the resistance to draw of the
filter.
[0011] The resistance to draw can also be varied by other
capabilities of the apparatus, thus increasing flexibility of the
apparatus according to the invention. Due to the apparatus being
capable of processing different types of sheet material the
resistance to draw can be varied through selection of the type of
sheet material processed. As an example, it is possible to select
paper or plastic film. Also, single layer sheet materials or
multi-layer sheet materials can be selected. Still further, due to
the apparatus being capable of processing sheet materials having
different thicknesses the resistance to draw can be varied through
selection of the thickness of the sheet material processed by the
apparatus. Yet further, due to the apparatus being capable of
processing sheet materials having different widths the resistance
to draw can be varied through selection of the width of the sheet
material processed by the apparatus. The width of the sheet
material is related to the density of the crimped sheet material in
the filter after rod formation. Therefore, the apparatus according
to the invention is very flexible and allows the supply of crimped
sheet material which allows the production of filters of a large
variety of types and properties. In addition, an apparatus
according to the invention is particularly advantageous as the cost
for manufacture filters comprising crimped sheet material is
typically lower than the cost for manufacture of filters comprising
cellulose acetate tow.
[0012] According to one aspect of the apparatus according to the
invention, the crimping unit comprises a first pair of crimping
rollers for engaging and crimping the continuous web of sheet
material being transported between them. The crimping rollers have
a surface which is provided with means adapted to crimp the sheet
material in the direction of transport of the sheet material.
Preferably, the crimping rollers have a surface which is provided
with means adapted to crimp the sheet material in the longitudinal
direction of the sheet material. By way of example, the means
adapted to crimp the sheet material in the direction of transport
of the sheet material may comprise a structure on the surface of
the rollers. In particular such a structure may comprise for
example crests and troughs running circumferentially about the axis
of rotation of the rollers. The sheet material is crimped by
transferring the structure to the sheet material as it passes
between the rollers. The grooved structure transferred to the sheet
material is particularly suitable to receive the add-on material,
in particular in case the add-on material is a particulate
material, or comprises capsules or beads. Crimping the sheet
material in the longitudinal direction also reduces the stability
of the sheet material in a transverse direction. Thus, the
subsequent formation of the rod (compression of the sheet material
into a cylindrical form) which is then cut to form the individual
filters is facilitated.
[0013] In accordance with another aspect of the invention, the
crimping unit comprises a second pair of crimping rollers for
engaging and crimping the continuous web of sheet material being
transported between them. The crimping rollers of the second pair
of crimping rollers have a surface which is provided with means
adapted to crimp the sheet material in a direction transverse to
the direction of transport of the sheet material. The term
"transverse to the direction of transport of the sheet material" is
to be understood to include directions other than perpendicular to
the direction of transport of the sheet material. Preferably, the
crimping rollers have a surface which is provided with means
adapted to crimp the sheet material in a direction perpendicular to
the direction of transport. By way of example, the means adapted to
crimp the sheet material in the direction transverse to the
direction of transport of the sheet material may comprise a
structure on the surface of the rollers. This structure may
comprise crests and troughs running in a direction parallel to the
axis of rotation of the rollers. This structure is preferably
provided on the entire surface of the rollers, so that the sheet
material is crimped by transferring the structure of the rollers to
the sheet material as it passes between the rollers. Alternatively,
in some applications, it may be sufficient to crimp the sheet
material only in sections in a transverse direction, such that some
sections are crimped and others remain uncrimped in a transverse
direction.
[0014] According to yet a further aspect of the invention, the
crimping unit comprises both a first pair of crimping rollers
having a surface being provided with means adapted to crimp the
sheet material in a longitudinal direction relative to the
direction of transport of the sheet material, and a second pair of
crimping rollers having a surface being provided with means adapted
to crimp the sheet material in a direction transverse to the
direction of transport of the sheet material. This embodiment
allows both the crimping of the sheet material in the longitudinal
direction as well as in the transverse direction, resulting in a
specific pattern being transferred to the sheet material as the
sheet material passes between the first and second pairs of
rollers. The structure on the surface of the respective pair of
rollers can be embodied as described above.
[0015] For any of the afore-described embodiments the particulate
or liquid add-on material added to the crimped sheet material by
the dispensing unit is preferably dispensed into the structure
created in the crimped sheet material, for example into the
longitudinally running troughs, into the transversely running
troughs, or into the depressions of the pattern generated by the
first and second pairs of rollers. This is particularly
advantageous in case the add-on material is a particulate material.
The particulate material dispensed into these troughs or
depressions is retained therein as the crimped sheet material is
subsequently fed into the rod forming device where the crimped
sheet material is then compressed to form a rod. Since preferably
no further handling steps of the sheet material are required
between adding the add-on material and the rod forming device, the
added particulate or liquid material stays in place, for example in
the crimped structure in case of particulate material or is not
transferred to other locations for example if liquid material does
not immediately dry.
[0016] In accordance with still another aspect of the invention,
the apparatus further comprises a cutting unit for cutting the
continuous web of sheet material to a predetermined width.
[0017] The cutting unit is arranged upstream of the crimping unit
when viewed in the direction of transport of the sheet material.
This aspect is advantageous since it allows cutting of the sheet
material to different widths, which, as mentioned above, allows to
control the density of the filter rod. For this purpose, the
cutting elements are displaceable in a direction perpendicular to
the direction of transport of the sheet material. Preferably, the
cutting elements are symmetrically displaceable relative to the
center line of the path along which the sheet material is
transported through the apparatus. This allows cutting the sheet
material of the web to a desired width and offers many
advantages.
[0018] For example, the filters of regular filter cigarettes have a
diameter of about 7.6 millimeters (mm), while the filters of
so-called "slim cigarettes" have a diameter of about 7.1
millimeters (mm). Accordingly, when a web of sheet material has
been processed for the production of filters for regular filter
cigarettes and it is now desired to switch to the production of
filters for slim cigarettes, up to now the bobbin carrying the web
for the filters of regular filter cigarettes is replaced with a
bobbin carrying a web having the width required for the filters of
slim filter cigarettes. This replacement of the bobbin is a
comparatively laborious and time consuming process. One advantage
of the embodiment of the apparatus comprising the afore-described
cutting unit is that such replacement of the bobbin is no longer
required. Instead, the cutting unit can be adjusted to cut the
sheet material for the production of filters for regular filter
cigarettes to the width required for the filters of slim filter
cigarettes as the web of sheet material passes the cutting
unit.
[0019] A further advantage of the cutting unit is that it allows
for an easy variation of the resistance to draw. By cutting the
sheet material to a smaller width, the amount of crimped sheet
material contained in the filter is reduced whereby the resistance
to draw is lowered given that the other parameters, for example the
amount of particulate or liquid add-on material dispensed, remain
unchanged. Also, if a particular resistance to draw is desired and
a specific sheet material is to be processed the sheet material can
be cut to a width which is such that after the crimping and rod
formation results in the desired resistance to draw. Accordingly,
this allows the processing of different types of sheet materials,
for example paper or plastic film, as well as of different widths
of sheet materials.
[0020] According to yet another aspect of the invention, the
winding unit may comprise a motor for driving the bobbin on which
the sheet material is provided, and a brake. The control unit
controls the motor and the brake in a manner such as to prevent the
continuous web of sheet material from rupturing. In the state of
the art, so far, the sheet material is pulled through the apparatus
by the crimping rollers or by additional drive rollers of the
crimping unit. According to the present invention, the motor of the
winding unit assists in the unwinding of the sheet material from
the bobbin which is particularly advantageous in case the sheet
material is fragile. A fragile sheet material is prone to rupturing
upon application of too high a pulling force by the rollers pulling
the sheet material through the apparatus. The occurrence of an
excessively high pulling force can thus be avoided. Preferably, the
control unit receives a signal indicative of the actual tension of
the sheet material. This signal can be processed and the motor of
the winding unit can be controlled in response. Also, the brake of
the winding unit can be controlled by the control unit. As the
bobbin is close to getting empty, that is, at the time there is
only little sheet material left on the bobbin, rotation of the
bobbin must be stopped. The brake serves to achieve a smooth
braking profile in order to avoid rupturing of the sheet material
during this phase.
[0021] In accordance with a still further aspect of the invention,
the apparatus further comprises a tensioning unit comprising a
controlled actuator for applying and maintaining a predetermined
tension to the sheet material during the transport of the sheet
material through the apparatus. While passive tensioning units are
known in the art, a tensioning unit comprising a controlled
actuator is advantageous in that it allows active control of the
tension applied to the sheet material. For example, known prior art
tensioning units comprise a passive tensioning element having a
fixed mass or weight through which tension is applied to the sheet
material, however, this tension cannot be actively controlled. By
way of example, the controlled actuator in accordance with this
aspect of the invention may be a controlled pneumatic actuator, a
controlled hydraulic actuator, a controlled electric actuator or
may be any suitable other type of controlled actuator, in order to
actively control the tension applied to the sheet material.
[0022] In accordance with yet a further aspect of the invention,
the apparatus further comprises a softening unit which is arranged
upstream of the crimping unit. The softening unit serves to
facilitate the crimping operation by softening the sheet material
to be crimped. By way of example, the softening unit may comprise a
heat source for raising the temperature of the sheet material to be
crimped. Such a softening unit comprising a heat source is
particularly advantageous for plastic sheet material. An increase
in temperature of the plastic sheet material softens the sheet
material and may thus facilitate crimping of the sheet material.
Any conventional heat source can be used for that purpose, such as
for example an infrared radiator. Alternatively or in combination,
the softening unit may comprise a moisture control means which is
capable of raising or lowering the moisture content of the sheet
material. For example, for raising the moisture content of paper
sheet material, the moisture control means may comprise a nozzle
arrangement for moisturizing the paper sheet material to be
crimped. Should the moisture content be too high, the heat source
may be activated to lower the moisture content of the paper sheet
material.
[0023] The above-mentioned cutting unit is particularly useful in
combination with the dispensing unit.
[0024] Further advantageous aspects of the invention will become
apparent from the following description of an embodiment of the
apparatus according to the invention with the aid of the drawings
in which:
[0025] FIG. 1 shows a schematic representation of an embodiment of
the apparatus according to the invention;
[0026] FIG. 2 shows a schematic representation of a first
embodiment of two crimping rollers of the apparatus according to
the invention; and
[0027] FIG. 3 shows a schematic representation of a second
embodiment of two crimping rollers (upper right) of the apparatus
according to the invention, as well as of two schematic (upper and
lower left) arrangements of crests and troughs provided on the
surface of the crimping rollers.
[0028] In FIG. 1 an embodiment of the apparatus according to the
invention is shown in a schematic representation. The apparatus
comprises a driving unit 1 comprising driving rollers 10 for
drivingly engaging and transporting a sheet material 2 through the
apparatus. For example, the sheet material 2 may be paper or a
suitable plastics film. The sheet material 2 is stored as a reel 20
on a bobbin 21 from which the sheet material 2 can be unwound with
the aid of a winding unit 3.
[0029] Winding unit 3 comprises a motor 30 and a brake 31 capable
of acting on the bobbin 21 so as to apply an additional driving or
braking force to the bobbin 21. This is described in more detail
below. A sensor 32 is provided in order to detect the distance
between the sensor 32 and the outermost layer of the reel 20 so as
to determine whether there is sufficient sheet material left on the
bobbin 21 to continue operation.
[0030] The sheet material 2 is transported through the apparatus in
the form of a web. A number of transport rollers 11 are provided
along the path of the web of sheet material 2 through the
apparatus. These transport rollers 11 serve to clamp or guide the
web of sheet material 2 on its path through the apparatus.
[0031] The apparatus further comprises a tensioning unit 4 for
applying and maintaining a predetermined tension to the web of
sheet material 2 as it is transported through the apparatus. For
this purpose, tensioning unit 4 comprises a controlled actuator 40
which can be actively controlled in order to always maintain the
desired predetermined tension to the web of sheet material 2 even
if the conditions during operation change.
[0032] The apparatus further comprises a cutting unit 5 for on-line
cutting the sheet material 2 to the desired width. As has been
explained above, if the width of the sheet material 2 to be
supplied by the apparatus is to be changed (for example, due to a
switching from the production of filters for regular filter
cigarettes to the production of filters for slim cigarettes, or for
any other reason, see above) it is no longer necessary to interrupt
production and to change the bobbin 21 carrying the reel 20, but
rather the cutting unit 5 allows to cut the sheet material 2
on-line to the desired width. The cutting unit 5 will be described
in more detail below.
[0033] The apparatus further comprises a softening unit 6 for
raising the temperature of the sheet material 2. The softening unit
is arranged upstream of a crimping unit 7 for crimping the sheet
material 2. The softening unit 6 assists in softening the sheet
material 2 to facilitate crimping of the sheet material 2. As has
already been explained above, softening unit 6 may comprise a heat
source such as an infrared radiator, however, it may also comprise
any other type of radiator suitable for this purpose. Such heat
source is particularly advantageous in case the sheet material 2 is
a plastic sheet material. Alternatively or in combination,
softening unit 6 may comprise a moisture control means which is
capable of raising or lowering the moisture content of the sheet
material 2. This is particularly advantageous in case the sheet
material 2 is a paper sheet material. For example, for raising the
moisture content of the paper sheet material, the moisture control
means may comprise a nozzle arrangement for moisturizing the paper
sheet material to be crimped. Should the moisture content be too
high, the heat source may be activated to lower the moisture
content of the paper sheet material.
[0034] As already mentioned, the apparatus further comprises
crimping unit 7 for crimping the sheet material 2. Crimping unit 7
may comprise a longitudinal crimping unit 70, or a lateral crimping
unit 71, or both a longitudinal crimping unit 70 and a lateral
crimping unit 71. The longitudinal crimping unit 70 as well as the
lateral crimping unit 71 may comprise one or more pairs of rollers,
as will be described in more detail below with the aid of FIG. 2
and FIG. 3.
[0035] The apparatus further comprises a dispensing unit 8 for
adding particulate or liquid add-on material to the sheet material
2. As already mentioned, preferably the add-on material is a
particulate material or a liquid, which liquid does not alter the
resistance to draw. Dispensing unit 8 is arranged downstream of
crimping unit 7 when viewed in the direction of transport of the
sheet material 2, and upstream of a rod forming device to which the
sheet material is supplied by the apparatus directly after the
particulate or liquid material has been added. Suitable rod forming
devices are well-known in the art and, therefore, they are not
described in detail.
[0036] Finally, the apparatus comprises a control unit 9 for
controlling the various units, as this is indicated by the various
dashed lines and arrows in FIG. 1.
[0037] In operation, the sheet material 2 stored as a reel 20 is
unwound from the bobbin 21. Driving rollers 10 of driving unit 1
apply traction forces to the web of sheet material 2 causing the
sheet material 2 to be unwound from reel 20 stored on bobbin 21.
However, these forces may vary to some extent. Since rupturing of
the sheet material 2 must be avoided, as control unit 9 receives a
signal from driving unit 1 representative of high traction forces,
control unit 9 may cause motor 30 to apply additional torque to
bobbin 21 in order to prevent the sheet material 2 from rupturing.
In a similar manner, control unit 9 may cause brake 31 to slow down
the rotational speed of bobbin 21 so as to increase tension of the
sheet material 2 should the tension have become too low. Also, at
the time there is only a little amount of sheet material 2 left on
reel 20--this being detected by sensor 32--brake 31 assists in
controlling the rotational speed of bobbin 21 to avoid rupturing of
the sheet material 2 during the stopping phase.
[0038] As already mentioned above, tensioning unit 4 comprising
controlled actuator 40 assists in applying and maintaining a
predetermined tension of the sheet material 2. This enables a
reliable transport of the sheet material 2 through the apparatus
and on the other hand prevents the sheet material 2 from rupturing
by actively controlling the tension of the sheet material 2.
[0039] In the further path of the sheet material 2 through the
apparatus cutting unit 5 may cut the sheet material 2 to the
desired width in case the sheet material 2 unwound from reel 20
does not already have the required width. For that purpose, cutting
unit 5 may comprise two laterally adjustable cutting wheels 50
(only one of them being shown in FIG. 1) which may be adjusted in a
direction perpendicular to the direction of transport of the sheet
material 2. Preferably, the cutting wheels 50 are symmetrically
displaceable relative to a center line of the path of the sheet
material 2.
[0040] Turning back to FIG. 1, with the aid of softening unit 6 the
sheet material may be heated or moisturized prior to getting
crimped in order to soften the sheet material 2 to facilitate
crimping.
[0041] The sheet material 2 then enters crimping unit 7 which may
comprise either a longitudinal crimping unit 70, or a lateral
crimping unit 71, or both a longitudinal crimping unit 70 and a
lateral crimping unit 71. For example, lateral crimping unit 71
comprises a pair of crimping rollers 710 as shown in FIG. 2. As the
sheet material 2 passes through crimping rollers 710 it is crimped
in a direction transverse to the direction of transport of the
sheet material 2. In the embodiment shown in FIG. 2, the sheet
material 2 is crimped in a direction perpendicular to the direction
of transport, as this can be seen from the arrangement of the
crests 711 and troughs 712 on the surface of crimping rollers 710.
The dashed lines 713 on sheet material 2 shown in FIG. 2 are
intended to indicate the grooves that have been crimped into the
sheet material 2 in the direction of dashed lines 713.
[0042] Longitudinal crimping unit 70 may also comprise a pair of
rollers 700, as this is shown in FIG. 3 (upper right). However, in
contrast to lateral crimping unit 71 the rollers 700 of
longitudinal crimping unit 70 may comprise crests 701 and troughs
702 on the surface of crimping rollers which are arranged as this
is shown schematically in the upper left representation of FIG. 3.
The lower left representation shows an alternative arrangement of
crests 701 and troughs 702, however, although the peaks are shown
to have a sharp contour they may be rounded. As the sheet material
2 passes through the pair of rollers 700 it is crimped in the
longitudinal direction, that is, in the direction of transport of
the sheet material 2. In the left hand representations of FIG. 3,
the sheet material 2 passes out of the plane of the drawings
towards the observer.
[0043] Of course, the apparatus may also comprise both a
longitudinal crimping unit 70 and a lateral crimping unit 71. This
results in a pattern of longitudinally and transversely arranged
recesses in the sheet material.
[0044] Subsequently, the sheet material passes through the
dispensing unit 8 where the particulate or liquid add-on material,
preferably particulate matter, is added to the crimped sheet
material 2. The particulate matter may be dispensed into the
grooves crimped into the sheet material 2 by the crests 711 or 701
of the rollers 71 or 70, or into the recesses, respectively.
[0045] The sheet material to which the particulate material has
been added may then be drawn through a converging funnel to form a
rod of compressed sheet material containing the particulate matter.
This rod of compressed sheet material can then be processed by a
filter making apparatus in the conventional manner.
* * * * *