U.S. patent application number 17/588366 was filed with the patent office on 2022-05-19 for production of collapsible pouches having a fitment.
The applicant listed for this patent is BOSSAR HOLDING B.V.. Invention is credited to Jordi Canada Codina, Laurens Last, Juan Rojas Segura, Abel Saez Lopez, Johannes Wilhelmus Van Tuil, Jordi Vidal Camps.
Application Number | 20220152940 17/588366 |
Document ID | / |
Family ID | 1000006178704 |
Filed Date | 2022-05-19 |
United States Patent
Application |
20220152940 |
Kind Code |
A1 |
Saez Lopez; Abel ; et
al. |
May 19, 2022 |
PRODUCTION OF COLLAPSIBLE POUCHES HAVING A FITMENT
Abstract
A production machine for the production of collapsible pouches
having a fitment. The machine has a fitment sealing station with an
impulse sealing device comprising a first jaw and a second jaw and
with an actuator device configured to move the first and second
jaws relative to one another between an opened position and a
clamped position, as well as a cooling device configured to cool
each of the first and second jaws. The fitment sealing station is
configured to perform an impulse sealing cycle.
Inventors: |
Saez Lopez; Abel;
(Barcelona, ES) ; Last; Laurens; (SX Tilburg,
NL) ; Van Tuil; Johannes Wilhelmus; (Barcelona,
ES) ; Canada Codina; Jordi; (Barcelona, ES) ;
Vidal Camps; Jordi; (Barcelona, ES) ; Rojas Segura;
Juan; (Barcelona, ES) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOSSAR HOLDING B.V. |
AB Kampen |
|
NL |
|
|
Family ID: |
1000006178704 |
Appl. No.: |
17/588366 |
Filed: |
January 31, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2020/071308 |
Jul 28, 2020 |
|
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17588366 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 65/7841 20130101;
B29C 66/133 20130101; B29C 66/1122 20130101; B29C 65/745 20130101;
B29C 65/38 20130101; B29C 66/4322 20130101; B29C 65/32 20130101;
B29C 66/3494 20130101; B29C 66/4312 20130101; B29C 66/0044
20130101 |
International
Class: |
B29C 65/32 20060101
B29C065/32; B29C 65/38 20060101 B29C065/38; B29C 65/74 20060101
B29C065/74; B29C 65/78 20060101 B29C065/78; B29C 65/00 20060101
B29C065/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2019 |
NL |
2023583 |
Claims
1. A production machine for the production of collapsible pouches
having a fitment, said pouches each having walls made from
heat-sealable film material, preferably metal-free heat-sealable
film material, wherein the production machine comprises a fitment
sealing station that is configured to heat seal a plastic fitment
having an attachment portion in a non-bonded edge region between
opposed first and second walls made from heat-sealable film
material, wherein the non-bonded edge region has a length and a
height, wherein the fitment sealing station comprises: an impulse
sealing device comprising a first jaw and a second jaw, an actuator
device configured to move the first and second jaws relative to one
another between an opened position and a clamped position, a
cooling device configured to cool each of the first and second
jaws, wherein the first jaw has a first contoured front surface
configured to contact the edge region of a respective first wall of
the pouch, wherein the second jaw has a second contoured front
surface configured to contact the edge region of a respective
second wall of the pouch, wherein the first and second contoured
front surfaces each have a recessed face portion defining a recess
configured to receive therein a half of the attachment portion of
the fitment, and wherein the first and second contoured front
surfaces each define, on opposite sides of the respective recessed
face and adjoining said recessed face, coplanar face portions,
wherein each of the first and second jaws comprises at the
respective contoured front surface thereof at least one, e.g. a
single elongated, impulse heatable member that extends along the
recessed face portion and the coplanar face portions of the
respective front surface and that is covered by a heat-resistant
non-stick covering, wherein the production machine is configured
such that, in operation, the fitment is positioned with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls made from heat-sealable film
material, and wherein the fitment sealing station is configured to
perform an impulse sealing cycle, wherein the actuator device is
configured to bring the first and second jaws into the clamped
position, so that--in the edge region--the first and second walls
are clamped against the attachment portion of the fitment by the
recessed faces of the first and second jaws and so that--in the
edge region--the first and second walls on opposite sides of the
fitment are clamped against one another by the coplanar faces of
the first and second jaws, and wherein the fitment sealing station
is configured to, in the clamped position, temporarily energize the
impulse heatable members so as to generate an impulse of heat that
is emitted by each of the impulse heatable members, which impulses
of heat seal the edge region of the first and second walls to the
attachment portion of the fitment and to each other on opposite
sides of the attachment portion, wherein the first and second jaws,
at least the impulse heatable members thereof, cool down after
termination of the energizing assisted therein by operation of the
cooling device, and wherein the actuator device is configured to
move the first and second jaws into the opened position after the
impulse heatable members have cooled down, wherein each impulse
heatable member is a susceptor element comprising electrically
conductive material, said susceptor element having a rear side
facing away from the respective contoured front surface, and
wherein each of the first and second jaws comprises an inductor
which is electrically insulated from the respective susceptor
element, wherein the inductor comprises an elongated inductor
section that extends along the respective contoured front surface
at the rear side of the respective at least one susceptor element,
and wherein the fitment sealing station comprises a high frequency
electric current source, which is connected to the inductor of each
of the first and second jaws, wherein the fitment sealing station
is configured so that, in the impulse sealing cycle, the electric
current source is operated to temporarily feed a high frequency
electric current to the inductors, thereby generating a high
frequency electromagnetic field with the inductors, wherein the
high frequency electromagnetic field induces eddy currents in the
respective susceptor element generating an impulse of heat that is
emitted by the susceptor element, which impulses of heat seal the
edge region of the walls to the attachment portion of the fitment
and to each other.
2. A production machine according to claim 1, wherein the at least
one elongated inductor section is a solid cross-section metal
inductor section, having a constant cross-section over its length
along the contoured front surface of the respective jaw.
3. A production machine according to claim 1, wherein the elongated
inductor section has, seen in a top view onto the jaw, a shape
corresponding to the contoured front surface of the jaw and
maintains a uniform distance between the susceptor element and the
elongated inductor section.
4. A production machine according to claim 1, wherein the inductor
of a jaw comprises multiple elongated inductor sections that are
parallel to one another.
5. A production machine according to claim 1, wherein the inductor
of a jaw comprises multiple elongated inductor sections that are
parallel to one another and vertically spaced from one another by a
horizontal slit, e.g. an air slit or a slit filled with
electrically insulating material, for example wherein there is just
one pair of elongated inductor sections that are parallel to one
another and vertically spaced from one another by a horizontal slit
arranged in proximity of the rear side of the susceptor
element.
6. A production machine according to claim 5, wherein said slit
between neighbouring inductor sections that are arranged above one
another has a height between 0.01 and 5 mm, more preferably between
0.1 and 2 mm.
7. A production machine according to claim 5, wherein the susceptor
element, seen in a view onto the front of the jaw, extends over the
slit between parallel elongated inductor sections and overlaps in
said view with each of the parallel inductor sections.
8. A production machine according to claim 5, wherein the susceptor
element is embodied as one strip that extends over the slit between
parallel elongated inductor sections and overlaps in said view with
each of the parallel inductor section.
9. A production machine according to claim 1, wherein the inductor
of a jaw is embodied so that in a pair of adjacent and parallel
inductor sections arranged at the rear side of the susceptor
element, the current flows in opposite directions through the
inductor sections.
10. A production machine according to claim 1, wherein the at least
one elongated inductor section has a thickness of between 1.0 and
4.0 mm, seen perpendicular to the front surface of the jaw, for
example between 1.5 and 3.0 mm.
11. A production machine according to claim 1, wherein at least one
cooling fluid duct extends along the at least one inductor section
that extends along the rear side of the susceptor element.
12. A production machine according to claim 1, wherein the
susceptor element is made of metal material, e.g. a metal or a
metal alloy, e.g. of a thin metal strip.
13. A production machine according to claim 1, wherein the
susceptor element is embodied as a strip having opposed front and
rear main faces that define the thickness of the strip between
them, and wherein, preferably, the thickness of the susceptor
element strip is constant over the extension of the strip, and/or
wherein the height of the strip is between 3 and 10 millimetres,
e.g. between 4 and 8 millimeters.
14. A production machine according to claim 1, wherein the
susceptor element, e.g. embodied as a strip, has a thickness of
between 0.01 and 5 mm, preferably between 0.05 and 2 mm, more
preferably between 0.08 and 0.8 mm, e.g. of between 0.3 and 0.5
mm.
15. A production machine according to claim 1, wherein the jaw is
provided with a single continuous susceptor element embodied as a
strip, e.g. of metal, having a height of the strip between 3 and 10
millimetres, e.g. between 4 and 8 millimeters, and a thickness of
between 0.08 and 0.8 mm, e.g. of between 0.08 and 0.5 mm.
16. A production machine according to claim 1, wherein the jaw is
provided with a resilient backing layer behind the susceptor
element, thereby allowing for the jaw front to accommodate for a
local variation of the number of film material walls.
17. A production machine according to claim 1, wherein the spacing
between the rear of the susceptor element and the neighbouring
inductor section(s) is at a minimum 0.025 mm, or 0.05 mm, or 0.1 mm
and at a maximum 3.0 mm, or 2.0 mm, or 1.0 mm.
18. A production machine according to claim 1, wherein the spacing
between the front surface of the jaw and the susceptor element is
at a minimum 0.025 mm, or 0.050 mm, and at a maximum 2.0 mm, or 1.0
mm, or 0.5 mm, wherein, preferably, said spacing is filled with
multiple layers of electrically insulating material, for example at
least a layer of Kapton and a layer of Teflon as anti-stick layer
forming the front surface of the jaw.
19. A production machine according to claim 1, wherein the
contoured front surface of the jaw is smooth in a region of contact
with the walls of film material, at least in the recessed portion
thereof.
20. A production machine according to claim 1, wherein the jaws are
configured, e.g. have a length, so that the entire non-bonded edge
region in which the fitment is inserted, e.g. by a fitment inserter
of the machine, is sealed in one cycle by the operation of the
jaws.
21. A production machine according to claim 1, wherein the sealing
device is configured to provide a heat impulse with the susceptor
element of between at least 150.degree. C. and at most any of
200.degree. C., 300.degree. C., 400.degree. C., or 500.degree. C.
measured on the susceptor element.
22. A production machine according to claim 1, wherein the heat
impulse duration lies between 10 and 1000 milliseconds, e.g.
between 20 and 500 milliseconds, e.g. between 75 and 400
milliseconds.
23. A production machine according to claim 1, wherein the cycle
includes a clamped cooling phase directly following the heat
impulse during which the jaws are maintained in clamped position,
which clamped cooling phase may have a duration between 200 and 800
milliseconds, e.g. between 300 and 600 milliseconds.
24. A production machine according to claim 1, wherein the
production machine comprises a conveyance mechanism that is
configured to convey individual pouches or a string of
interconnected pouches along a path of conveyance in a continuous
motion, said path at least extending along the fitment sealing
station, and wherein the sealing station comprises a motion device
that is configured to move the first and second jaws in
synchronicity with the continuously moving pouch or string of
pouches during the impulse sealing cycle.
25. A method for the production of collapsible pouches having a
fitment, e.g. a spout, wherein use is made of a production machine
according to claim 1.
Description
[0001] A first aspect of the present invention relates to the
production of collapsible pouches having a fitment, e.g. spouted
collapsible pouches.
[0002] For the production of spouted collapsible pouches, it is
known to make use of a production machine having a spout sealing
station that is configured to heat seal a plastic spout having an
attachment portion in a non-bonded edge region between opposed
first and second walls made from heat-sealable film material.
[0003] In a well-known embodiment, the spout sealing station
comprises a sealing device with a first jaw and a second jaw and
with an actuator device configured to move the first and second
jaws relative to one another between an opened position and a
clamped position. In this sealing device, each of the jaws has a
contoured front surface configured to contact the edge region of a
respective wall. These contoured front surfaces each have a
recessed face portion defining a recess configured to receive
therein a half of the attachment portion of the spout. The
contoured front surfaces of the jaws further each define, on
opposite sides of the respective recessed face and adjoining said
recessed face, coplanar face portions. The jaws of the sealing
device are continuously heated, e.g. electrically, to a temperature
suited for heat sealing. This is known as the hot-bar sealing
technique. In operation, the spout is positioned, by means of a
spout inserter device of the production machine, with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls that are made from heat-sealable
film material. The continuously heated jaws are then moved into the
clamped position. The maximum temperature of the heated jaws is
generally limited by the characteristics of the film material of
the pouch. Therefore, time, pressure, and temperature are the main
parameters that govern this heat sealing process. The pressure is
commonly rather significant to effect a proper sealing.
[0004] In view of the conditions during this common practice type
of heat sealing of the spout into the non-bonded edge region,
numerous developments have been made over the years to enhance the
continuously heated jaws sealing process and improve the quality of
the resulting joint. For example, US2007205202 discloses a molded
plastic spout having an attachment portion with a central tubular
portion that delimits a section of the product passage and with
parallel planar weld ribs, extending in vertically spaced apart
planes that are perpendicular to the central tubular portion.
Vertical partition walls protrude diametrically from the central
tubular portion and perpendicular to the planar weld ribs. At their
perimeter each of these weld ribs may be provided with an
integrally molded thin weld burr, that melts rapidly in a heat
sealing process with heated jaws. The result is a heat sealing onto
the attachment portion along parallel joint lines. Another example
is US2014110433 wherein the heat sealing faces of the attachment
portion of the molded plastic spout are provided with a relief
structure, e.g. undulating ridges and furrows, with a height of
about 0.1 to 0.5 millimeters above the main surface.
[0005] In the field of pouch production, it is also known to make
use of an impulse sealing device, such as offered by ROPEX
Industrie-Elektronik GmbH, Bietigheim-Bissingen, Germany. In known
embodiments of such an impulse sealing device, at least one of the
jaws has a single, elongated, impulse heatable resistor band that
extends along the front surface of the jaw and is covered by a
heat-resistant non-stick covering, e.g. a Teflon tape. The device
is configured to perform an impulse sealing cycle, wherein the
actuator device is configured to bring the first and second jaws
into the clamped position, e.g. with two walls of heat sealable
film material in between. The sealing device is configured to, in
the clamped position, temporarily pass an electric current through
the resistor band so as to generate an impulse of heat that is
emitted by the resistor band. This brief impulse of heat seals the
walls onto each other. The jaw cools down after termination of the
energizing of the resistor band, assisted therein by operation of
the associated cooling device. The actuator device is configured to
move the first and second jaws into the opened position after the
cooling down has been achieved. The temperature of the resistor
band may in practical embodiments increase from room temperature or
a slightly elevate temperature extremely fast to 300.degree. C. or
thereabout, so in general very fast to a very high temperature
which is maintained only for a very short duration. The impulse
sealing approach is for instance discussed in DE19737471.
[0006] The first aspect of present invention aims to provide
measures that provide an improved impulse sealing that is employed
in the production of collapsible pouches having a fitment, e.g.
spouted collapsible pouches.
[0007] The first aspect of the present invention aims to provide
measures that enhance the quality of the seal that is obtained
between the attachment portion of the fitment and the film
material.
[0008] The first aspect of the invention provides a production
machine for the production of collapsible pouches having a fitment,
e.g. a spout, said pouches each having walls made from
heat-sealable film material, preferably metal-free heat-sealable
film material, wherein the production machine comprises a spout
sealing station that is configured to heat seal a plastic fitment
having an attachment portion in a non-bonded edge region between
opposed first and second walls made from heat-sealable film
material, wherein the non-bonded edge region has a length and a
height,
wherein the fitment sealing station comprises: [0009] an impulse
sealing device comprising a first jaw and a second jaw, [0010] an
actuator device configured to move the first and second jaws
relative to one another between an opened position and a clamped
position, [0011] a cooling device configured to cool each of the
first and second jaws, wherein the first jaw has a first contoured
front surface configured to contact the edge region of a respective
first wall of the pouch, wherein the second jaw has a second
contoured front surface configured to contact the edge region of a
respective second wall of the pouch, wherein the first and second
contoured front surfaces each have a recessed face portion defining
a recess configured to receive therein a half of the attachment
portion of the fitment, and wherein the first and second contoured
front surfaces each define, on opposite sides of the respective
recessed face and adjoining said recessed face, coplanar face
portions, wherein each of the first and second jaws comprises at
the respective contoured front surface thereof at least one, e.g. a
single elongated, impulse heatable member that extends along the
recessed face portion and the coplanar face portions of the
respective front surface and that is covered by a heat-resistant
non-stick covering, wherein the production machine is configured
such that, in operation, the fitment is positioned with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls made from heat-sealable film
material, and wherein the fitment sealing station is configured to
perform an impulse sealing cycle, wherein the actuator device is
configured to bring the first and second jaws into the clamped
position, so that--in the edge region--the first and second walls
are clamped against the attachment portion of the fitment by the
recessed faces of the first and second jaws and so that--in the
edge region--the first and second walls on opposite sides of the
fitment are clamped against one another by the coplanar faces of
the first and second jaws, and wherein the fitment sealing station
is configured to, in the clamped position, temporarily energize the
impulse heatable members so as to generate an impulse of heat that
is emitted by each of the impulse heatable members, which impulses
of heat seal the edge region of the first and second walls to the
attachment portion of the fitment and to each other on opposite
sides of the attachment portion, wherein the first and second jaws,
at least the impulse heatable members thereof, cool down after
termination of the energizing assisted therein by operation of the
cooling device, and wherein the actuator device is configured to
move the first and second jaws into the opened position after the
impulse heatable members have cooled down, wherein each impulse
heatable member is a susceptor element comprising electrically
conductive material, said susceptor element having a rear side
facing away from the respective contoured front surface, and
wherein each of the first and second jaws comprises an inductor
which is electrically insulated from the respective susceptor
element, wherein the inductor comprises an elongated inductor
section that extends along the respective contoured front surface
at the rear side of the respective at least one susceptor element,
and wherein the fitment sealing station comprises a high frequency
electric current source, which is connected to the inductor of each
of the first and second jaws, wherein the fitment sealing station
is configured so that, in the impulse sealing cycle, the electric
current source is operated to temporarily feed a high frequency
electric current to the inductors, thereby generating a high
frequency electromagnetic field with the inductors, wherein the
high frequency electromagnetic field induces eddy currents in the
respective susceptor element generating an impulse of heat that is
emitted by the susceptor element, which impulses of heat seal the
edge region of the walls to the attachment portion of the fitment
and to each other.
[0012] Due to the extension of the at least one elongated inductor
section at the rear side of the at least one susceptor element,
preferably in close proximity to said rear side, and along the
contoured front surface, the development of heat over the extension
of the front of the jaw takes place in an attractive manner, in
particular in a rather uniform manner. The elongation of the
inductor section contributes to the homogeneity of the current
density within the inductor section, e.g. compared to a coiled or
another rather irregular shape of an inductor section. This
homogeneity translates into homogeneity of the high frequency
field, and thereby to homogeneity of the impulse heating of the
susceptor element. The latter contributes to a reliable and
effective heat sealing in the edge region between the walls of film
material and between the walls of film material and the attachment
portion of the fitment.
[0013] The homogeneity of the heat sealing and the impulse process
allow to have a minimal clamping force of the jaws in the clamped
position, e.g. far less than with the traditional continuous heated
jaws. The clamping force may effectively only serve to assure an
intimate surface contact between the walls and between the walls
and the attachment portion. As discussed herein, preferred
embodiment allow to enhance the intimacy of said contact, e.g. so
as to exclude the presence of pockets of air between the surfaces
to be joined by the heat sealing.
[0014] The fitment can for example be a spout for discharge of
product from the pouch, e.g. a flowable product, e.g. a flowable
food product, e.g. a beverage, sauce, etc. The fitment can have a
neck that is closed or is configured to be closed by a closure
member.
[0015] In an embodiment, the fitment is molded from a polymer, such
as polyethylene (PE), for example high-density polyethylene (HDPE)
or low-density polyethylene (LDPE), and/or polypropylene (PP),
and/or polyethylene terephthalate (PET).
[0016] Preferably, the fitment is molded from a single type of a
polymer, e.g. a mono-material, such as polyethylene (PE), for
example high-density polyethylene (HDPE) and/or low-density
polyethylene (LDPE), or polypropylene (PP), or polyethylene
terephthalate (PET).
[0017] In a practically advantageous embodiment, the fitment is
made of high-density polyethylene (HDPE) and the film material is
made from one or more layers of polyethylene (PE), possibly
multiple PE--layers with an intermediate layer of Ethylene vinyl
alcohol (EVOH) as an oxygen barrier, e.g. for food packaging. A
film material with a single type of polymer may still comprise a
certain amount of EVOH, typically up to 5 wt %, whilst still being
characterized as a mono-material. This embodiment is favoured in
view of recyclability, for example.
[0018] The fitment can for example be a valve type fitment, a
connector type fitment, etc. For example, the fitment comprises a
slit valve, a bidon-type valve, etc., e.g. in combination with a
cap, e.g. an overcap.
[0019] The provision of the induction impulse heatable member may
provide that the start-up time, e.g. the time wherein the sealing
station can become operable from an inactive state, is fairly
limited. Compared to the known sealing stations with continuously
heated jaws, it is not necessary to bring the jaws towards the
sealing temperature, which required up to 30 minutes in the known
sealing stations. Instead, in the inventive approach, the jaws of
the sealing station may take less time to reach a steady state
temperature, typically only in between 1 and 2 minutes, for example
after the sealing station has been modified to make a different
type of seal, e.g. for a different pouch packaging.
[0020] In an embodiment, the elongated inductor section is made
from a metal, e.g. of copper.
[0021] In embodiments, the at least one elongated inductor section
is a solid cross-section metal or other, preferably high
conductivity material inductor section, e.g. made of copper which
is preferred. This arrangement allows to avoid undue variations of
current density within the inductor section, and thereby
undesirable variation in the generated field, e.g. compared to an
internally hollow inductor section. In alternative embodiment, the
at least one elongated inductor section is a multi-strand Litz
wire. It has been observed that in such embodiment, heating of the
Litz-wire may become problematic and cooling is difficult.
[0022] In embodiments, the at least one elongated inductor section
has a constant cross-section, preferably a solid cross-section,
over its length along the contoured front surface of the respective
jaw. This design avoids undue variations of current density within
the inductor section, which might otherwise occur at locations
where the cross-section changes, and thereby undesirable variation
in the generated field.
[0023] In embodiments, the uniform cross-section elongated inductor
section has, seen in a top view onto the jaw, a shape corresponding
to the contoured front surface of the jaw and maintains a uniform
distance between the susceptor element and the elongated inductor
section. This arrangement enhances uniformity of the development of
heat in the susceptor element.
[0024] In embodiments, the inductor of a jaw comprises multiple
elongated inductor sections that are parallel to one another.
[0025] In embodiments, the inductor of a jaw comprises multiple
elongated inductor sections that are parallel to one another and
vertically spaced from one another by a horizontal slit, e.g. an
air slit or a slit filled with electrically insulating material. In
embodiments, there is just one pair of elongated inductor sections
that are parallel to one another and vertically spaced from one
another by a horizontal slit arranged in proximity of the rear side
of the susceptor element.
[0026] In embodiments, said slit between neighbouring inductor
sections that are arranged above one another has a height between
0.01 and 5 mm, more preferably between 0.1 and 2 mm.
[0027] In an embodiment, the inductor of a jaw comprises a pair of
parallel inductor sections arranged at the rear side of the
susceptor element, the one inductor section above the other
inductor section, spaced from one another by an elongated slit,
e.g. an air slit or a slit filled with electrically insulating
material. In practical embodiments, there is just one pair of
inductor section above one another in the jaw.
[0028] The presence of the slit between the parallel elongated
inductor sections allows for a desirable concentration of the field
that is generated by the inductor of the jaw. In an embodiment, the
susceptor element extends, seen in a view onto the front surface of
the jaw, over a horizontal slit between parallel inductor
sections.
[0029] In an embodiment, the susceptor element, seen in a view onto
the front of the jaw, extends over the slit between parallel
elongated inductor sections and overlaps in said view with each of
the parallel inductor sections. Preferably, in an embodiment, the
susceptor element overlaps the entire height of the inductor
sections. In another embodiment, the amount of overlap between the
susceptor element and the parallel inductor sections is limited,
for example the susceptor element overlaps with each inductor
section over about 25% of the height of the inductor section. The
height, and length, of the susceptor element is generally chosen in
accordance with the seal to be made.
[0030] In an embodiment, the susceptor element is embodied as one
strip that extends over the slit between parallel elongated
inductor sections and overlaps in said view with each of the
parallel inductor section.
[0031] With the strip-like susceptor element extending over the
slit, the field generated by the inductor is advantageously
concentrated in the susceptor element.
[0032] In an embodiment, a strip shaped susceptor element has an
upper edge and a lower edge defining a height of the strip, wherein
the height of the strip is at least 50% of the height of the single
pair of inductor sections including the slit that are arranged at
the rear of the strip above one another, e.g. between 75% and 125%
of said height, e.g. about 100% of said height.
[0033] In an embodiment, a strip shaped susceptor element has an
upper edge and a lower edge defining a height of the strip, wherein
the inductor of a jaw comprises a number of, e.g. multiple,
inductor sections that each extend along the rear side of the
susceptor element. Herein the height of the strip is preferably at
most the same as the height of the number of one or more inductor
sections, preferably the upper edge and the lower edge of the strip
not protruding above and below the height of the one or more
inductor sections.
[0034] In an embodiment, the inductor of a jaw is embodied so that
in a pair of adjacent and parallel inductor sections that are
arranged at the rear side of the susceptor element, the current
flows in the same direction through the inductor sections.
[0035] In an embodiment, the inductor of a jaw is embodied so that
in a pair of adjacent and parallel inductor sections arranged at
the rear side of the susceptor element, the current flows in
opposite directions through the inductor sections.
[0036] In an embodiment, the inductor of a jaw comprises a C-shaped
inductor element having parallel first and second inductor sections
interconnected, e.g. by a bent portion, in series, wherein the free
ends of the inductor sections have terminals for electrical
connection to the current source.
[0037] In an embodiment, the inductor of a jaw comprises multiple
nested C-shaped inductor elements, each having parallel first and
second inductor sections interconnected in series, e.g. by a bent
portion, wherein the free ends of these inductor sections have
terminals for electrical connection to the current source. For
example, the inductor has two nested C-shaped inductor
elements.
[0038] In an embodiment, the first and/or second jaw is provided
with one C-shaped inductor element, having parallel first and
second inductor sections interconnected in series, wherein the free
ends of the inductor sections have terminals for electrical
connection to the current source.
[0039] In an embodiment, the inductor of a jaw comprises a C-shaped
inductor element having parallel first and second inductor sections
interconnected in series and arranged above one another, wherein
the inductor sections are separated by a horizontal slit, e.g. an
air slit or a slit filled with electrically insulating
material.
[0040] In an embodiment, the inductor of a jaw comprises multiple,
e.g. just two, elongated inductor sections arranged parallel to one
another and arranged above one another behind the susceptor
element.
[0041] In an embodiment, the susceptor element has a height and the
inductor of a jaw comprises multiple inductor sections arranged
parallel to one another and arranged above one another behind the
susceptor element.
[0042] In an embodiment, the inductor of a jaw has an inductor
element that is generally U-shaped seen from above, wherein each of
the first and second elongated inductor sections thereof has a
constant cross-section, preferably a solid cross-section, over its
length and wherein each of said first and second inductor sections
has a shape corresponding to the contoured front surface of the
respective jaw when seen in said view from above.
[0043] In an embodiment, the at least one elongated inductor
section has a thickness of between 1.0 and 4.0 mm, seen
perpendicular to the front surface of the jaw, for example between
1.5 and 3.0 mm. The limited thickness of the inductor element
enhances the cooling of the jaw, including the inductor of the jaw,
e.g. as one or more cooling fluid ducts are preferably arranged in
proximity of a rear side of the at least one inductor element.
[0044] In an embodiment the at least one elongated inductor section
has a rectangular cross-section with a height that is greater than
the thickness of the inductor section. This arrangement allows to
limit the thickness, which allows for efficient cooling.
[0045] Each jaw may be provided with one or more cooling fluid
ducts, e.g. the cooling fluid being a cooling liquid, e.g. water,
being passed through the cooling fluid ducts, e.g. using a pump
assembly, e.g. a cooling liquid circuit being a closed circuit
including a heat exchanger configured to remove heat from the
cooling liquid.
[0046] In an embodiment, or in combination with cooling by means of
cooling liquid, air cooling can be employed for the jaws. Yet, due
to the capacity, cooling by means of cooling liquid is preferred.
Preferably the cooling liquid is passed in close proximity to the
inductor of the jaw, e.g. directly behind the one or more elongated
inductor sections. Preferably, no cooling fluid is passed in a
region between the inductor and the susceptor as that would unduly
increase the distance between them and would impair effectivity of
the impulse heating induced by the field. It will be appreciated,
that in view of the desired very close proximity of the susceptor
element to the front surface of the jaw, there is in practice no
space for any cooling duct in said region. So, in practical
embodiments, cooling of the jaw is preferably done using a control
flow of cooling fluid, e.g. liquid, through one or more ducts that
are arranged behind, and preferably in close proximity to, the
inductor sections.
[0047] In an embodiment, at least one cooling fluid duct extends
along the at least one inductor section that extends along the rear
side of the susceptor element.
[0048] It is preferred for the machine to be configured such that
cooling of the jaw is active during the entire impulse sealing
cycle, so also during the creation of the heat impulse which
happens so fast that it is generally not impaired by the cooling.
In another configuration, the cooling may be interrupted or reduced
around the moment of the heat impulse.
[0049] The cooling of the jaws may, as preferred, be configured to
cause cooling of the heat-sealed edge region before the jaws are
opened, e.g. the film material and fitment being cooled to below
60.degree. C. before opening, e.g. to below 40.degree. C.
[0050] The cooling of the jaws may, as preferred, be configured to
cause cooling of the heat-sealed edge region before the jaws are
opened, e.g. the film material and fitment being cooled to below
the crystallization temperature of the polymer material involved in
the join.
[0051] A benefit of the cooling is that, before the release from
the jaws, the sealed fitment securing region of the pouch will
acquire a strength and rigidity that is greater than in absence of
such cooling. This, for instance, may allow for an increased
production speed of the machine wherein higher forces may be
exerted on the walls of the pouch, e.g. in view of transport of the
pouch or string of interconnected pouches through the machine.
Undue stretching of the pouch, e.g. in the area of the fitment
seal, is preventable to a large degree by use of the invention
disclosed herein.
[0052] In an embodiment, the susceptor element is made of metal
material, e.g. a metal or a metal alloy, e.g. of a thin metal
strip.
[0053] For example, the susceptor element is made of, or comprises,
aluminium, nickel, silver, stainless steel, molybdenum and/or
nickel-chrome.
[0054] In an embodiment, the susceptor element is embodied as a
strip having opposed front and rear main faces that define the
thickness of the strip between them. In an embodiment, the
thickness of the susceptor element strip is constant over the
extension of the strip.
[0055] In an embodiment, the susceptor element is embodied as a
planar strip, most preferably the jaw having a single planar strip
susceptor element. This arrangement as a planar strip is in
particular preferred for the handling of plastic fitments that have
an attachment portion with planar and preferably smooth sealing
faces. Herein, preferably, the plane of the susceptor element is
parallel to the plane of the sealing face of the attachment portion
of the fitment. The preferred smoothness of the sealing faces, so
the absence of a relief that locally holds the wall of film
material away from the sealing face and creates air pockets between
the wall and the sealing face, causes a very effective transfer of
the heat impulse from the jaw to the zone where the joint is made.
In practice, it can be observed that a joint is achieved through
the entirety of the area where the susceptor emits heat towards the
sealing face of the attachment portion.
[0056] In an embodiment, the susceptor element comprises a
paramagnetic material, a diamagnetic material, or a ferromagnetic
material. Such magnetic materials may be effected by an
electromagnetic field, in order to achieve eddy currents that cause
the mentioned rapid heating in the impulse sealing technique.
[0057] In an embodiment, the susceptor element is a strip, e.g. of
a metal, e.g. of aluminium, wherein the height of the strip is
between 3 and 10 millimetres, e.g. between 4 and 8 millimeters. For
example, as preferred, the strip has a constant height over its
length.
[0058] Preferably, the susceptor element strip lacks apertures over
its extension.
[0059] In an embodiment, the jaw is provided with a single
continuous susceptor element embodied as a strip, e.g. of
metal.
[0060] In an embodiment, the susceptor element, e.g. embodied as a
strip, has a thickness of between 0.01 and 5 mm, preferably between
0.05 mm and 2 mm, more preferably between 0.08 mm and 0.8 mm, e.g.
of between 0.08 mm and 0.5 mm. In general, it is considered
desirable to have a minimum thickness of the susceptor element in
view of the desire to rapidly cool the jaw, including the inductor
and the susceptor, after termination of the heat impulse. A thin
design of the susceptor contributes to this desire. It is noted
that, in contrast to the impulse sealing device addressed in the
introduction, no electric current from a current source is passed
through the susceptor, so the cross-section need not be designed to
deal with such a current flow.
[0061] In an embodiment, the jaw is provided with a single
continuous susceptor element embodied as a strip, e.g. of metal,
having a height of the strip between 3 and 10 millimetres, e.g.
between 4 and 8 millimeters, and a thickness of between 0.08 and
0.8 mm, e.g. of between 0.08 and 0.5 mm. For example, the strip is
made of aluminium material.
[0062] In embodiments, the frequency of the alternating electric
current supplied to the inductor is between 100 kHz and 1 MHz, for
example between 250 KHz and 750 KHz.
[0063] In embodiments, the magnitude of the electric current
supplied to the inductor is between 20 A and 600 A.
[0064] In embodiment, the electric current is supplied to the
inductor at a voltage with a magnitude between 40 V and 500 V.
[0065] In an embodiment, a jaw is embodied such that the high
frequency electromagnetic field generated by the inductor primarily
causes the very rapid development of heat within a frontal skin
layer of the susceptor element due to the so-called skin effect.
The skin effect is the tendency of an alternating electric current
to become distributed within a conductor such that the current
density is largest near the surface of the conductor and decreases,
exponentially, with greater depths of the conductor. At high
frequencies the skin depth becomes smaller. This depth may, for
example, be 0.15 mm for an aluminium susceptor element if the
frequency of the field is 350 KHz. The thickness of the susceptor
element is envisaged to be more than this skin depth, yet not too
much for the reason addressed herein.
[0066] In case of a pouch with one or more side gussets, the edge
region where the fitment is to be mounted may include a so-called
triple point. In such a situation, it can be advantageous to
provide a resilient backing layer behind the susceptor element,
thereby allowing for the jaw front to accommodate for a local
variation of the number of film material walls. As known in the art
of pouch production the triple point is where there are two walls
to be joined on one side of the point, and wherein there are two
pairs of two wall segments (so four wall thicknesses in total) to
be joined on the other side of the triple point. For example, in an
embodiment, a silicone rubber layer or a Teflon layer is provided
behind the susceptor element. For example, the resilient layer has
a thickness between 0.3 and 2.0 millimeter, preferably between 0.4
and 0.7 mm. Herein it is understood that the thin susceptor element
is able to flex so as to accommodate the local variation in the
number of walls.
[0067] The provision of a resilient backing layer is preferably not
done, so a resilient backing is preferably absent, unless truly
required. This is in view of the thermal insulating effect provided
by such an additional layer which may hamper the cooling action of
the cooling device. Also the additional layer may increase the
spacing between the inductor section and the susceptor element in
an undesirable manner.
[0068] In an embodiment, the spacing between the rear of the
susceptor element and the neighbouring inductor section(s) is at a
minimum 0.025 mm, or 0.05 mm, or 0.1 mm and at a maximum 3.0 mm, or
2.0 mm, or 1.0 mm. The minimum values of this spacing are primarily
envisaged to allow for effective electrical insulation between the
inductor section(s) on the one hand and the susceptor element on
the other hand. In embodiments, it is envisaged that this spacing
is only filled with electrically insulating material. The maximum
value of this spacing is primarily envisaged to have the inductor
section(s) in close proximity to the rear of the susceptor element,
wherein a maximum of 1.0 mm is preferred. In a practical embodiment
this spacing may be 0.05 mm. Therefore, this spacing may in
practical embodiments be less than the thickness of the susceptor
element itself.
[0069] Preferably, the entire spacing between the rear of the
susceptor element and the neighbouring inductor section(s) is
filled with electrically insulating material.
[0070] In an embodiment, the spacing between the rear of the
susceptor element and the neighbouring inductor section is filled
with one or more layers of electrically insulating material, e.g.
tape, for example at least a layer of Kapton tape and a layer of
Teflon tape, for each just one layer of Kapton tape and one Layer
of Teflon tape.
[0071] In an embodiment, the electrical insulation between the rear
of the susceptor element and the neighbouring inductor section(s)
has a thickness of between a minimum of 0.025 mm, or 0.050 mm, or
0.1 mm, and a maximum of at most 3.0 mm, or 2.0 mm.
[0072] In an embodiment, the anti-stick layer at the front of the
jaw is embodied as a layer of Teflon tape. In another embodiment,
the anti-stick layer could comprise glass or the like.
[0073] In an embodiment, the front face of the susceptor element is
covered by a layer of electrically insulating material, e.g. tape,
e.g. Kapton tape, e.g. having a thickness of between 0.01 mm and
0.05 mm, e.g. of about 0.025 mm.
[0074] In an embodiment, the spacing between the front surface of
the jaw and the susceptor element is at a minimum 0.025 mm, or
0.050 mm, and at a maximum 2.0 mm, or 1.0 mm, or 0.5 mm. Herein,
the minimum spacing may be governed by the presence of an
anti-stick layer. The anti-stick layer can be coated onto the jaw,
e.g. onto the susceptor element, e.g. a glass or Teflon
coating.
[0075] In an embodiment, the spacing between the front surface of
the jaw and the susceptor element is filled with multiple layers of
electrically insulating tape, for example at least a layer of
Kapton tape and a layer of Teflon tape as anti-stick layer forming
the front surface of the jaw, for each just one layer of Kapton
tape and one Layer of Teflon tape.
[0076] In an embodiment, the contoured front surface of the jaw is
smooth in a region of contact with the walls of film material, at
least in the recessed portion thereof, so lacking any relief that
would locally keep the film material away from the front surface,
so lacking for example one or more ribs, bosses, etc. This
arrangement is preferred in conjunction with a smooth design of the
sealing faces of the fitment attachment portion. Preferably, the
smooth region of contact of the front surface of the jaw, at least
in the recessed portion of the front surface, is designed to be
parallel to the sealing surface of the attachment portion of the
fitment that is to be joined to the walls of film material.
[0077] In an embodiment, the jaws are configured, e.g. have a
length, so that the entire non-bonded edge region in which the
fitment is inserted, e.g. by a fitment inserter of the machine, is
sealed in one cycle by the operation of the jaws. So both the
fitment is secured in the edge region and the entirety of the edge
region is sealed closed. This avoids the needs for additional
sealing actions along said edge region. In another embodiment, only
the part where the fitment is located is sealed in the cycle, with
another part remaining open. This, for example, allows for filling
of the pouch via said open part. This open part is then later
closed in another sealing step, e.g. also based on impulse sealing
as disclosed herein.
[0078] In an embodiment, the recessed face portion of each jaw is
composed of a curved central face portion adjoined at both sides
thereof by a rectilinear face portion. In another embodiment, the
recessed face portion is curvaceous over its entire extension.
[0079] The embodiment wherein the recessed face portion of each jaw
is composed of a curved central face portion adjoined at both sides
thereof by a rectilinear face portion, is preferred in conjunction
with a fitment having an attachment portion of similar design, so
with a sealing face of the attachment portion being composed of a
curved (outwardly convex) central sealing face portion adjoined at
both sides thereof by a rectilinear sealing face portion. Such a
design of the attachment portion is, for example, shown in FIGS. 3
and 4 of WO03/031280. The presence of straight portions is
advantageous in view of the homogeneity of the heat impulse that
can be created to effect the join in those regions, e.g. compared
to non-straight portions.
[0080] The impulse sealing technique for the fitment as discussed
herein is advantageously applicable for a fitment with an
attachment portion that has thin sealing walls, e.g. the sealing
walls depending from a transverse wall of the fitment body. The
sealing walls may have a thickness of less than 2 mm, in practical
embodiments.
[0081] Preferably, the sealing walls are smooth on their sealing
faces, so lacking any relief that keeps the film material locally
away from the sealing wall in the desired region of the join.
[0082] In embodiments, one or both jaws have a main body, e.g. of
plastic or ceramic material, e.g. a heat-resistant material, e.g.
of PEEK, on which the susceptor element and/or the inductor are
mounted. The plastic or ceramic material is selected to not impair
the field that is generated by the inductor, at least not in an
undesirable manner. Boron nitride and/or Aluminium nitride,
Polyphenylene sulphide, vulcanized silicone materials can be
considered as well for the main body. In particular, Boron nitride
provides for a good thermal conductivity, thereby enabling a good
conductivity of heat from the susceptor element and inductor
towards the cooling device, e.g. towards the cooling fluid
circulated through the jaw.
[0083] The main body can be 3D-printed if desired.
[0084] For example, the one or more cooling ducts are provided,
e.g. machined, in the main body.
[0085] For example, one or more cooling ducts extend generally in
parallel to the one or more inductor sections, e.g. one duct behind
each inductor section.
[0086] For example, one or both jaws have a main body, e.g. of
plastic or ceramic material, having a main body front side into
which one or more grooves are made in which the one or more
inductor sections are arranged. In embodiments, the susceptor
element is arranged over the main body front side, as discussed
herein relative to the one or more inductor sections. Herein, one
or more layers of electrically insulation material are arranged
between the inductor section(s) and the susceptor element, e.g. of
Kapton and/or Teflon. One or more further layers of electrically
insulating material as well as an outer anti-stick covering are
mounted over the susceptor element to from the front surface of the
jaw.
[0087] In embodiment, the sealing device is configured to provide a
heat impulse with the susceptor element of between at least
150.degree. C. and at most any of 200.degree. C., 300.degree. C.,
400.degree. C., or 500.degree. C. measured on the susceptor
element. It is noted that due to the, often, very short duration of
the heat impulse and the highly dynamic changes of the temperature,
directly measuring this temperature requires complex/expensive
temperature measurement equipment. On the basis of the inputted
electrical energy and analysis of heat flow/loss, the temperature
that is achieved can be approximated.
[0088] In an embodiment, the heat impulse duration lies between 10
and 1000 milliseconds, e.g. between 20 and 500 milliseconds, e.g.
between 75 and 400 milliseconds.
[0089] In an embodiment, the cycle includes a clamped cooling phase
directly following the heat impulse during which the jaws are
maintained in clamped position, which clamped cooling phase may
have a duration between 200 and 800 milliseconds, e.g. between 300
and 600 milliseconds. In practical embodiments, the clamped cooling
phase may be longer than the heat impulse as cooling is slowed down
by the thermal insulating properties of plastic materials.
[0090] It is noted that control of the temperature that is reached
during the impulse heating may be done on the basis of monitoring
and controlling, the supply of electrical power to the inductor
and/or by monitoring and controlling the temperature and/or flow
rate of cooling fluid, e.g. water, circulated along the respective
jaws.
[0091] In an embodiment, the sealing device, e.g. a control unit
thereof, is configured to effect a preheating of the susceptor
element before the actual impulse heat sealing is carried out. For
example, the susceptor element is preheated to a preheating
temperature of between 50 and 120 degrees Celsius, e.g. between 60
and 80 degrees Celsius, before the heat impulse is carried out at a
higher temperature of the susceptor element. The preheating may
take place at a preheating temperature that is preferably low
enough to prevent the film material to be significantly influenced.
At the same time, the preheating reduces the difference in
temperature between that of the susceptor, prior to the heat
impulse, and the desired temperature of the susceptor during the
heat impulse. The reduced temperature difference provides that the
peak temperature during the heat impulse may be reached in less
time and that the high frequency electromagnetic field only needs
to be provided for a shorter period of time. As such, the required
time for the heat sealing may be reduced, resulting in an increased
production rate. Furthermore, the shorter heat impulse time may
serve to avoid a risk of damaging the film material.
[0092] In a further embodiment, the sealing device, e.g. a control
unit thereof, is configured to control preheating of the susceptor
element before the jaws are brought in the clamped position.
[0093] In an embodiment, the fitment, e.g. the attachment portion
thereof, is pre-heated prior to the impulse sealing. For example,
the attachment portion is exposed to an infrared heater. It is,
however, preferred to avoid a preheating of the fitment to be
sealed as this may impair the stability of the fitment and/or
require extended cooling after the heat impulse, thereby slowing
down the process.
[0094] In an embodiment, the production machine comprises at least
one temperature sensor configured to sense the actual temperature
of a jaw, e.g. of a front surface of the jaw, e.g. of or near the
susceptor element of the jaw, e.g. of the main body, which
temperature sensor is linked to a control unit of the current
source. Herein the control unit, e.g. computerized, is configured
to adjust the current that is fed to the inductor on the basis of
the output of the temperature sensor. For example, the current
source is adjusted with respect to a preheating of the jaws and/or
the impulse heating. Alternatively or additionally, the control
unit, e.g. computerized, is configured to adjust the temperature
and/or flow rate of cooling fluid circulated along the respective
jaws on the basis of the output of the temperature sensor. For
example, the cooling device is adjusted with respect to a
preheating of the jaws and/or the impulse heating.
[0095] The controlling may take place via a feedback-type control
mechanism, such that measured values during a first sealing cycle
forms the basis for controlling the current source and/or cooling
device, in order to influence the impulse heating and/or cooling
for subsequent sealing cycles.
[0096] In an embodiment, the control unit may be configured to log
during production of pouches one or more sealing parameters in
relation to the produced pouches, such as one or more actual
settings of the current source and/or the cooling device, in order
to be able to retrieve afterwards which seal, e.g. which pouch has
been made at which specific setting(s). This may contribute to the
monitoring of the quality of the seals in the pouches that are
being made.
[0097] In an embodiment, the temperature sensor is configured and
used to measure the temperature of at least one of the jaws in a
phase of the cycle that is distinct from the heat impulse phase
itself. For example, the temperature is measured when the jaws are
in their opened position. For example, the temperature sensor is a
contactless temperature sensor, e.g. aimed at the front surface of
a jaw.
[0098] In an embodiment, a temperature measurement performed during
one or more cycles, is used to adjust the current source for
performance of one or more subsequent impulse sealing cycles.
[0099] The production machine is primarily envisaged for production
of pouches from metal-free film material. For example, the film
material of the walls is a multi-layer material where one and the
same plastic, but with different properties, is found in all
layers. In another embodiment the wall is a monolayer wall. The
absence of a metal layer allows for more effective recycling.
[0100] In an embodiment, the film material, preferably metal-free
film material, comprises one or more layers each comprising or
consisting of polyethylene (PE), for example high-density
polyethylene (HDPE) or low-density polyethylene (LDPE), and/or
polypropylene (PP), and/or polyethylene terephthalate (PET). The
film material may thereby comprise a mixture of two or more of
these polymers, a laminate with one or more layers each consisting
of one or more polymers, or a single layer with a single one of
these polymers. These polymers may have different properties, for
example in terms of mechanical strength and/or sealing
capabilities, which may all be used to obtain a suitable material
for the pouches.
[0101] In an embodiment, the film material is made entirely from
polyethylene (PE), for example high-density polyethylene (HDPE) or
low-density polyethylene (LDPE), polypropylene (PP), or
polyethylene terephthalate (PET). According to this embodiment, the
film material consists of a single type of polymer, e.g. a
mono-material which may optionally allow the film material to
consist of a single polymeric layer. The use of only a single
polymer may improve the recyclability of the pouch, since it may no
longer be required to separate the various polymers, since the
pouch wall only comprises a single polymer. Also any metal layer is
absent.
[0102] In an embodiment, the film material includes a layer of
Ethylene vinyl alcohol (EVOH) as an oxygen barrier, e.g. for food
packaging, e.g. as a substitute for a metal layer in the film which
is preferably absent. A film material with a single type of polymer
as defined above may still comprise a certain amount of EVOH,
typically up to 5 wt %, whilst still being characterized as a
mono-material.
[0103] In an embodiment, the film material is printed, e.g. a
surface print being provided on the side that is contacted by a jaw
of the sealing station having a susceptor and inductor. The impulse
sealing does not impair the quality of the surface print in
contrast to the use of continuously heated seal jaws. In an
embodiment, the film material is subjected to inline surface
printing of the film material, e.g. just prior to the sealing as
disclosed herein.
[0104] In an embodiment, the fitment is molded from the same
polymer as the walls of the pouch, or a rather similar polymer to
enhance recycling.
[0105] In an embodiment, the fitment is molded from a polymer, such
as polyethylene (PE), for example high-density polyethylene (HDPE)
or low-density polyethylene (LDPE), and/or polypropylene (PP),
and/or polyethylene terephthalate (PET). The fitment material may
thereby be molded from a single one of these polymers or a
mixture/blend of two or more of these polymers. These polymers may
have different properties, for example in terms of mechanical
strength and/or sealing capabilities, which may all be used to
obtain a suitable material for the fitments.
[0106] In an embodiment, the fitment is molded from a single type
of a polymer, e.g. a mono-material, such as polyethylene (PE), for
example high-density polyethylene (HDPE) or low-density
polyethylene (LDPE), or polypropylene (PP), or polyethylene
terephthalate (PET). The use of only a single polymer may improve
the recyclability of the pouch, since it may no longer be required
to separate the various polymers, since the fitment only comprises
a single polymer.
[0107] In a further embodiment, the fitment is molded from a
polyethylene (PE), such as high-density polyethylene (HDPE) or
low-density polyethylene (LDPE). Typically, the high-density
polyethylene (HDPE) may be stronger and/or more stable than the
low-density polyethylene (LDPE), but may also be more rigid. In
prior art sealing stations with continuously-heated jaws, it was
considered impractical for pouchmaking to heat seal a fitment made
of high-density polyethylene (HDPE) to a pouch wall made of
polyethylene (PE) only, e.g. in absence of a metal layer in the
film, since the rigid HDPE fitment appeared to damage the pouch
wall during sealing, as a result of the relatively high
temperatures and the large clamping forces required in the prior
art approach. With the present induction based impulse sealing, the
temperature peak of the heat impulse is only present for a very
short time and the clamping force may be very low, thereby enabling
the sealing of fitments made of high-density polyethylene (HDPE),
without damaging mono-material pouch walls.
[0108] In a further embodiment, the fitment is molded from a
polyethylene (PE), preferably from high-density polyethylene (HDPE)
or low-density polyethylene (LDPE), and the film material is made
entirely from polyethylene (PE), preferably from low-density
polyethylene (LDPE). The use of only a single polymer, e.g.
polyethylene (PE), and the lack of a metal layer, may improve the
recyclability of the pouch, since it may no longer be required to
separate the various polymers or to separate the fitment from the
pouch walls, since the fitment and the pouch both consist of the
same polymer, e.g. polyethylene (PE).
[0109] In an alternative embodiment, the fitment is molded from
polypropylene (PP) and the film material is made entirely from
polypropylene (PP). The use of only a single polymer, e.g.
polypropylene (PP), and the lack of a metal layer, may improve the
recyclability of the pouch, since it may no longer be required to
separate the various polymers or to separate the fitment from the
pouch walls, since the fitment and the pouch both consist of the
same polymer, e.g. polypropylene (PP).
[0110] In an embodiment, the production machine is embodied with a
conveyance mechanism that is configured to convey individual
pouches or a string of interconnected pouches along a path of
conveyance, wherein the sealing station as discussed herein is
arranged along said path of conveyance. In an embodiment, the
conveyance mechanism is configured and operated to convey in an
intermittent motion pattern, so stepwise. Often a so-called walking
beam conveyance mechanism is employed for stepwise conveyance. The
sealing action is then performed with the pouch at rest, in
practical embodiments with the sealing station mounted stationary
in the machine, at least with regards to the direction of
conveyance.
[0111] In an embodiment, the conveyance mechanism is configured and
operated to convey individual pouches or a string of interconnected
pouches along a path of conveyance in a continuous motion, so
without stopping and starting. Herein it is envisaged that the
sealing station comprises a motion device that allows to move a
pair of jaws in synchronicity with the continuously moving pouch or
string of pouches during the impulse sealing cycle. An advantage of
this approach that undesirable deformations of the pouch are
avoided, which would otherwise result from rapid stopping and
starting. For example, the sealing station comprises an endless
motion device wherein one or more, preferably multiple, sealing
devices are moved along an endless path that extends over a segment
thereof along the path of conveyance.
[0112] In the continuous motion device, it is preferred for the
cooling device to be embodied such that continuous circulation of
coolant through the one or more cooling ducts in the jaws can be
established. This may entail the use of one or more rotary
couplings to connected, for example, one or more hoses connected to
the jaws via the one or more rotary couplings to a stationary
mounted pumping and heat exchanger system.
[0113] In an embodiment, the machine comprises one or more of:
[0114] a roll handling station adapted to receive one or more rolls
of heat-sealable film material, [0115] one or more pouch forming
stations adapted and operated to form the film material dispensed
by the roll handling station into a succession of pouches, e.g.
distinct pouches or a string of still interconnected pouches, each
pouch having at least one non-bonded edge region between two
opposed walls of the pouch, for example a pouch forming station
being embodied as a folding station, e.g. to fold film material
dispensed from a single roll into a shape with a bottom gusset, for
example a pouch forming station being embodied as a cutting
station, e.g. to make one or more cuts to shape and/or separate,
e.g. in part, the pouches, [0116] a fitment inserting device
adapted to insert the attachment portion of the fitment in the
non-bonded edge region, [0117] the fitment sealing station as
discussed herein, [0118] a feed mechanism adapted and operated to
feed said formed pouches, e.g. separate or as a string of still
interconnected pouches, to the fitment inserting device and the
fitment sealing device, which devices may be located at one at the
same station, [0119] a fitment feeder adapted and operated to feed
plastic fitments to the fitment inserting device.
[0120] In embodiments, the machine is configured for production of
pouches having one or more gussets, e.g. in a side and/or in a
bottom of the pouch, e.g. with the fitment being heat sealed
between the walls at the top of the pouch.
[0121] In embodiments, the machine comprises a filling station,
configured to fill a product into the pouch.
[0122] In an embodiment, the filling station is configured to fill
the product into the pouch prior to the sealing of the fitment to
the pouch as discussed herein. The filling can then, for example,
be performed via the non-bonded edge region into which the fitment
is sealed at a later stage in the manner as discussed herein.
[0123] In an embodiment, the filling of the pouch on the production
machine is done after performing the impulse sealing cycle at the
mentioned station. For example, the filling is done via the
fitment, e.g. in an aseptic filling device, optionally followed by
a closing step wherein the fitment is closed, e.g. in a capping
station provided with a capping device configured and operated to
place a cap on the fitment.
[0124] In an embodiment, the pre-made spout supplied to the spout
inserter device is part of a pre-made fitment-closure assembly
comprising the spout and a closure member closing said spout, so
that after performing the impulse sealing step that secures the
spout and closes the edge region and any additional sealing of all
non-bonded regions a hermetically closed pouch is obtained. In an
embodiment, this pouch is then empty. For example, the hermetically
closed, still empty pouch, is then transferred to a remote filling
device, where a product is filled into the pouch via the spout,
e.g. in an aseptic filling device, wherein the filling device
removes or opens the closure member, fills the product into the
pouch, followed by a closing step wherein the spout is closed, e.g.
by moving the closure member into a closed position thereof, e.g.
replacing the closure member back onto the spout, or by replacing
the removed closure member by another closure member, e.g. in a
capping station provided with a capping device configured and
operated to place a cap on the spout.
[0125] In an embodiment, the machine comprises a film material
sterilization station that is configured to subject the film
material dispensed from the one or more rolls to a sterilization
process. In an embodiment, the machine is provided with a sterile
or aseptic chamber that extends from said film material
sterilization station onwards until and including the fitment
sealing station, preferably also past any further sealing station,
so that the formation of a hermetically closed pouch is performed
in said sterile or aseptic chamber.
[0126] In an embodiment, a filling station is arranged in or along
said sterile or aseptic chamber, so that both the production of the
pouch and the filling of the pouch, and preferably also the
hermetic sealing of the pouch (e.g. by provision of the spout,
possible already closed or possibly closed by a later capping
action) is done within the one sterile or aseptic chamber.
[0127] In an embodiment, the production machine comprises one or
more additional sealing devices in order to seal the walls of film
material in other regions in order to produce the pouches. This is
commonly known in the art. For example, a side sealing device is
provided that is configured to establish a side or vertical seal of
the pouch, e.g. side seals along opposite vertical side of the
pouch in a horizontal form-fill-seal machine. For example, a bottom
sealing device is provided that is configured to establish a bottom
seal of the pouch, e.g.
[0128] In an embodiment, all sealing devices of the production
machine, including the fitment sealing device as discussed herein,
are located at one and the same station of the production machine.
For example, the sealing devices acting in succession to provide
the various seals without the film material being moved relative to
the sealing devices during the entirety of the various sealing
steps. In an embodiment, all said sealing devices are arranged in
one sterile or aseptic chamber of the production machine.
[0129] The first aspect of the invention also relates to a method
for the production of collapsible pouches having a fitment, e.g. a
spout, wherein use is made of a production machine as described
herein.
[0130] The first aspect of the invention also relates to a fitment
sealing station for use in the production of collapsible pouches as
described herein.
[0131] The first aspect of the invention also relates to an impulse
sealing device for use in the production of collapsible pouches as
described herein.
[0132] A second aspect of the invention relates to a production
machine for the production of collapsible pouches having a fitment,
said pouches each having walls made from heat-sealable film
material, preferably metal-free heat-sealable film material,
wherein the production machine comprises a fitment sealing station
that is configured to heat seal a plastic fitment having an
attachment portion in a non-bonded edge region between opposed
first and second walls made from heat-sealable film material,
wherein the non-bonded edge region has a length and a height,
wherein the fitment sealing station comprises: [0133] an impulse
sealing device comprising a first jaw and a second jaw, [0134] an
actuator device configured to move the first and second jaws
relative to one another between an opened position and a clamped
position, [0135] a cooling device configured to cool each of the
first and second jaws, wherein the first jaw has a first contoured
front surface configured to contact the edge region of a respective
first wall of the pouch, wherein the second jaw has a second
contoured front surface configured to contact the edge region of a
respective second wall of the pouch, wherein the first and second
contoured front surfaces each have a recessed face portion defining
a recess configured to receive therein a half of the attachment
portion of the fitment, and wherein the first and second contoured
front surfaces each define, on opposite sides of the respective
recessed face and adjoining said recessed face, coplanar face
portions, wherein each of the first and second jaws comprises at
the respective contoured front surface thereof at least one, e.g. a
single elongated, impulse heatable member that extends along the
recessed face portion and the coplanar face portions of the
respective front surface and that is covered by a heat-resistant
non-stick covering, wherein the production machine is configured
such that, in operation, the fitment is positioned with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls made from heat-sealable film
material, and wherein the fitment sealing station is configured to
perform an impulse sealing cycle, wherein the actuator device is
configured to bring the first and second jaws into the clamped
position, so that--in the edge region--the first and second walls
are clamped against the attachment portion of the fitment by the
recessed faces of the first and second jaws and so that--in the
edge region--the first and second walls on opposite sides of the
fitment are clamped against one another by the coplanar faces of
the first and second jaws, and wherein the fitment sealing station
is configured to, in the clamped position, temporarily energize the
impulse heatable members so as to generate an impulse of heat that
is emitted by each of the impulse heatable members, which impulses
of heat seal the edge region of the first and second walls to the
attachment portion of the fitment and to each other on opposite
sides of the attachment portion, wherein the first and second jaws,
at least the impulse heatable members thereof, cool down after
termination of the energizing assisted therein by operation of the
cooling device, and wherein the actuator device is configured to
move the first and second jaws into the opened position after the
impulse heatable members have cooled down, wherein the production
machine comprises a conveyance mechanism that is configured to
convey individual pouches or a string of interconnected pouches
along a path of conveyance in a continuous motion, said path at
least extending along the fitment sealing station, and wherein the
sealing station comprises a motion device that allows to move the
first and second jaws in synchronicity with the continuously moving
pouch or string of pouches during the impulse sealing cycle.
[0136] The second aspect of the invention allows to achieve a high
production rate, as the impulse sealing cycle can be short and as
there is no start and stopping of the pouches, or string of
interconnected pouches, for the sealing.
[0137] In the second aspect of the invention the impulse heatable
member can be embodied as a resistor band through which an electric
current is passed to create the impulse of heat, e.g. as described
in DE19737471.
[0138] In the second aspect the invention the impulse heatable
member can be embodied as a susceptor element comprising
electrically conductive material, said susceptor element having a
rear side facing away from the respective contoured front
surface,
wherein each of the first and second jaws comprises an inductor
which is electrically insulated from the respective susceptor
element, and wherein the fitment sealing station comprises a high
frequency electric current source, which is connected to the
inductor of each of the first and second jaws, wherein the fitment
sealing station is configured so that, in the impulse sealing
cycle, the electric current source is operated to temporarily feed
a high frequency electric current to the inductors, thereby
generating a high frequency electromagnetic field with the
inductors, wherein the high frequency electromagnetic field induces
eddy currents in the respective susceptor element generating an
impulse of heat that is emitted by the susceptor element, which
impulses of heat seal the edge region of the walls to the
attachment portion of the fitment and to each other.
[0139] In an embodiment of the second aspect of the invention, the
inductor comprises an elongated inductor section that extends along
the respective contoured front surface at the rear side of the
respective at least one susceptor element.
[0140] The fitment sealing station may be embodied with details as
described herein with reference to the first aspect of the
invention, including one or more of the optional and/or preferred
details thereof, e.g. as stated in the appended claim set.
[0141] The second aspect of the invention also relates to a method
for production of collapsible pouches using the production
machine.
[0142] A third aspect of the present invention relates to a
production machine for the production of collapsible pouches having
a fitment, said pouches each having walls made from heat-sealable
film material, preferably metal-free heat-sealable film material,
wherein the production machine comprises a fitment sealing station
that is configured to heat seal a plastic fitment having an
attachment portion in a non-bonded edge region between opposed
first and second walls made from heat-sealable film material,
wherein the non-bonded edge region has a length and a height,
wherein the fitment sealing station comprises: [0143] an impulse
sealing device comprising a first jaw and a second jaw, [0144] an
actuator device configured to move the first and second jaws
relative to one another between an opened position and a clamped
position, [0145] a cooling device configured to cool each of the
first and second jaws, wherein the first jaw has a first contoured
front surface configured to contact the edge region of a respective
first wall of the pouch, wherein the second jaw has a second
contoured front surface configured to contact the edge region of a
respective second wall of the pouch, wherein the first and second
contoured front surfaces each have a recessed face portion defining
a recess configured to receive therein a half of the attachment
portion of the fitment, and wherein the first and second contoured
front surfaces each define, on opposite sides of the respective
recessed face and adjoining said recessed face, coplanar face
portions, wherein each of the first and second jaws comprises at
the respective contoured front surface thereof at least one, e.g. a
single elongated, impulse heatable member that extends along the
recessed face portion and the coplanar face portions of the
respective front surface and that is covered by a heat-resistant
non-stick covering, wherein the production machine is configured
such that, in operation, the fitment is positioned with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls made from heat-sealable film
material, and wherein the fitment sealing station is configured to
perform an impulse sealing cycle, wherein the actuator device is
configured to bring the first and second jaws into the clamped
position, so that--in the edge region--the first and second walls
are clamped against the attachment portion of the fitment by the
recessed faces of the first and second jaws and so that--in the
edge region--the first and second walls on opposite sides of the
fitment are clamped against one another by the coplanar faces of
the first and second jaws, and wherein the fitment sealing station
is configured to, in the clamped position, temporarily energize the
impulse heatable members so as to generate an impulse of heat that
is emitted by each of the impulse heatable members, which impulses
of heat seal the edge region of the first and second walls to the
attachment portion of the fitment and to each other on opposite
sides of the attachment portion, wherein the first and second jaws,
at least the impulse heatable members thereof, cool down after
termination of the energizing assisted therein by operation of the
cooling device, and wherein the actuator device is configured to
move the first and second jaws into the opened position after the
impulse heatable members have cooled down, wherein each impulse
heatable member is a susceptor element comprising electrically
conductive material, said susceptor element having a rear side
facing away from the respective contoured front surface, and
wherein each of the first and second jaws comprises an inductor
which is electrically insulated from the respective susceptor
element, and wherein the fitment sealing station comprises a high
frequency electric current source, which is connected to the
inductor of each of the first and second jaws, wherein the fitment
sealing station is configured so that, in the impulse sealing
cycle, the electric current source is operated to temporarily feed
a high frequency electric current to the inductors, thereby
generating a high frequency electromagnetic field with the
inductors, wherein the high frequency electromagnetic field induces
eddy currents in the respective susceptor element generating an
impulse of heat that is emitted by the susceptor element, which
impulses of heat seal the edge region of the walls to the
attachment portion of the fitment and to each other, and wherein
the inductor and susceptor element in a jaw are configured such
that the high frequency electromagnetic field generated by the
inductor primarily causes a rapid development of heat within a
frontal skin layer of the susceptor element due to the skin
effect.
[0146] The fitment sealing station may be embodied with details as
described herein with reference to the first aspect of the
invention, including one or more of the optional and/or preferred
details thereof, e.g. as stated in the appended claimset.
[0147] The third aspect of the invention also relates to a method
for production of collapsible pouches using the production
machine.
[0148] A fourth aspect of the invention relates to a method for
production of collapsible pouches using a production machine for
the production of collapsible pouches having a fitment, said
pouches each having walls made from heat-sealable film material,
preferably metal-free heat-sealable film material, wherein the
production machine comprises a fitment sealing station that is
configured to heat seal a plastic fitment having an attachment
portion in a non-bonded edge region between opposed first and
second walls made from heat-sealable film material, wherein the
non-bonded edge region has a length and a height,
wherein the fitment sealing station comprises: [0149] an impulse
sealing device comprising a first jaw and a second jaw, [0150] an
actuator device configured to move the first and second jaws
relative to one another between an opened position and a clamped
position, [0151] a cooling device configured to cool each of the
first and second jaws, wherein the first jaw has a first contoured
front surface configured to contact the edge region of a respective
first wall of the pouch, wherein the second jaw has a second
contoured front surface configured to contact the edge region of a
respective second wall of the pouch, wherein the first and second
contoured front surfaces each have a recessed face portion defining
a recess configured to receive therein a half of the attachment
portion of the fitment, and wherein the first and second contoured
front surfaces each define, on opposite sides of the respective
recessed face and adjoining said recessed face, coplanar face
portions, wherein each of the first and second jaws comprises at
the respective contoured front surface thereof at least one, e.g. a
single elongated, impulse heatable member that extends along the
recessed face portion and the coplanar face portions of the
respective front surface and that is covered by a heat-resistant
non-stick covering, wherein the production machine is configured
such that, in operation, the fitment is positioned with the
attachment portion thereof in the non-bonded edge region, between
the opposed first and second walls made from heat-sealable film
material, and wherein the fitment sealing station is configured to
perform an impulse sealing cycle, wherein the actuator device is
configured to bring the first and second jaws into the clamped
position, so that--in the edge region--the first and second walls
are clamped against the attachment portion of the fitment by the
recessed faces of the first and second jaws and so that--in the
edge region--the first and second walls on opposite sides of the
fitment are clamped against one another by the coplanar faces of
the first and second jaws, and wherein the fitment sealing station
is configured to, in the clamped position, temporarily energize the
impulse heatable members so as to generate an impulse of heat that
is emitted by each of the impulse heatable members, which impulses
of heat seal the edge region of the first and second walls to the
attachment portion of the fitment and to each other on opposite
sides of the attachment portion, wherein the first and second jaws,
at least the impulse heatable members thereof, cool down after
termination of the energizing assisted therein by operation of the
cooling device, and wherein the actuator device is configured to
move the first and second jaws into the opened position after the
impulse heatable members have cooled down, wherein the contoured
front surface of the jaw is smooth in a region of contact with the
walls of film material, at least in the recessed portion thereof,
devoid of any relief that would locally keep the film material away
from the front surface, wherein the sealing faces of the attachment
portion of the fitment are smooth, devoid of any relief that would
locally keep the film material away from the sealing surface.
[0152] All methods described in the present application are
primarily envisaged for the production of pouches from metal-free
film material. For example, the film material of walls of the pouch
is a multi-layer material where one and the same plastic, but with
different properties, is found in all layers. In another embodiment
the wall is a monolayer wall. The absence of a metal layer allows
for more effective recycling. It is noted that the presence of a
metal layer in the film material, is also envisaged in the context
of the present applications. The impulse sealing is equally
possible in the presence of such metal layer.
[0153] In embodiments of the methods, the film material, preferably
metal-free film material, comprises one or more layers each
comprising or consisting of polyethylene (PE), for example
high-density polyethylene (HDPE) or low-density polyethylene
(LDPE), and/or polypropylene (PP), and/or polyethylene
terephthalate (PET). The film material may thereby comprise a
mixture of two or more of these polymers, a laminate with one or
more layers each consisting of one or more polymers, or a single
layer with a single one of these polymers. These polymers may have
different properties, for example in terms of mechanical strength
and/or sealing capabilities, which may all be used to obtain a
suitable material for the pouches.
[0154] In embodiments of the methods, the film material is made
entirely from polyethylene (PE), for example high-density
polyethylene (HDPE) or low-density polyethylene (LDPE),
polypropylene (PP), or polyethylene terephthalate (PET). According
to this embodiment, the film material consists of a single type of
polymer, e.g. a mono-material which may optionally allow the film
material to consist of a single polymeric layer. The use of only a
single polymer may improve the recyclability of the pouch, since it
may no longer be required to separate the various polymers, since
the pouch wall only comprises a single polymer. Also, any metal
layer is absent.
[0155] In embodiments of the methods, the film material includes a
layer of Ethylene vinyl alcohol (EVOH) as an oxygen barrier, e.g.
for food packaging, e.g. as a substitute for a metal layer in the
film which is preferably absent. A film material with a single type
of polymer as defined above may still comprise a certain amount of
EVOH, typically up to 5 wt %, whilst still being characterized as a
mono-material.
[0156] In an embodiment, the film material is printed, e.g. a
surface print being provided on the side that is contacted by a jaw
of the sealing station having a susceptor and inductor. The impulse
sealing does not impair the quality of the surface print in
contrast to the use of continuously heated seal jaws. In an
embodiment, the film material is subjected to inline surface
printing of the film material, e.g. just prior to the sealing as
disclosed herein.
[0157] In embodiments of the methods, the fitment is molded from
the same polymer as the walls of the pouch, or a rather similar
polymer to enhance recycling.
[0158] In embodiments of the methods, the fitment is molded from a
polymer, such as polyethylene (PE), for example high-density
polyethylene (HDPE) or low-density polyethylene (LDPE), and/or
polypropylene (PP), and/or polyethylene terephthalate (PET). The
fitment material may thereby be molded from a single one of these
polymers or a mixture/blend of two or more of these polymers. These
polymers may have different properties, for example in terms of
mechanical strength and/or sealing capabilities, which may all be
used to obtain a suitable material for the fitments.
[0159] In embodiments of the methods, the fitment is molded from a
single type of a polymer, e.g. a mono-material, such as
polyethylene (PE), for example high-density polyethylene (HDPE) or
low-density polyethylene (LDPE), or polypropylene (PP), or
polyethylene terephthalate (PET). The use of only a single polymer
may improve the recyclability of the pouch, since it may no longer
be required to separate the various polymers, since the fitment
only comprises a single polymer.
[0160] In further embodiments of the methods, the fitment is molded
from a polyethylene (PE), such as high-density polyethylene (HDPE)
or low-density polyethylene (LDPE). Typically, the high-density
polyethylene (HDPE) may be stronger and/or more stable than the
low-density polyethylene (LDPE), but may also be more rigid. In
prior art production methods that rely on sealing stations with
continuously-heated jaws, it was considered impractical for
pouchmaking to heat seal a fitment made of high-density
polyethylene (HDPE) to a pouch wall made of polyethylene (PE) only,
e.g. in absence of a metal layer in the film, since the rigid HDPE
fitment appeared to damage the pouch wall during sealing, as a
result of the relatively high temperatures and the large clamping
forces required in the prior art approach. With the present
induction based impulse sealing, the temperature peak of the heat
impulse is only present for a very short time and the clamping
force may be very low, thereby enabling the sealing of fitments
made of high-density polyethylene (HDPE), without damaging
mono-material pouch walls.
[0161] In further embodiments of the methods, the fitment is molded
from a polyethylene (PE), preferably from high-density polyethylene
(HDPE) low-density polyethylene (LDPE), and the film material is
made entirely from polyethylene (PE), preferably from low-density
polyethylene (LDPE). The use of only a single polymer, e.g.
polyethylene (PE), and the lack of a metal layer, may improve the
recyclability of the pouch, since it may no longer be required to
separate the various polymers or to separate the fitment from the
pouch walls, since the fitment and the pouch both consist of the
same polymer, e.g. polyethylene (PE).
[0162] In alternative embodiments of the methods, the fitment is
molded from polypropylene (PP) and the film material is made
entirely from polypropylene (PP). The use of only a single polymer,
e.g. polypropylene (PP), and the lack of a metal layer, may improve
the recyclability of the pouch, since it may no longer be required
to separate the various polymers or to separate the fitment from
the pouch walls, since the fitment and the pouch both consist of
the same polymer, e.g. polypropylene (PP).
[0163] In an embodiment, the recessed face portion of each jaw is
composed of a curved central face portion adjoined at both sides
thereof by a rectilinear face portion, wherein the sealing faces of
the attachment portion of the fitment are composed of a curved,
outwardly convex, central sealing face portion adjoined at both
sides thereof by a rectilinear sealing face portion. Such a design
of the attachment portion is, for example, shown in FIGS. 3 and 4
of WO03/031280. The presence of straight portions is advantageous
in view of the homogeneity of the heat impulse that can be created
to effect the join in those regions, e.g. compared to non-straight
portions.
[0164] In an embodiment, each of the first and second jaws has at
the respective contoured front surface thereof a single elongated,
impulse heatable member that extends along the recessed face
portion and the coplanar face portions of the respective front
surface and that is covered by a heat-resistant non-stick
covering.
[0165] In the fourth aspect of the invention the impulse heatable
member can be embodied as a resistor band through which an electric
current is passed to create the impulse of heat, e.g. as described
in DE19737471
[0166] In the fourth aspect the invention the impulse heatable
member can be embodied as a susceptor element comprising
electrically conductive material, said susceptor element having a
rear side facing away from the respective contoured front
surface,
wherein each of the first and second jaws comprises an inductor
which is electrically insulated from the respective susceptor
element, and wherein the fitment sealing station comprises a high
frequency electric current source, which is connected to the
inductor of each of the first and second jaws, wherein the fitment
sealing station is configured so that, in the impulse sealing
cycle, the electric current source is operated to temporarily feed
a high frequency electric current to the inductors, thereby
generating a high frequency electromagnetic field with the
inductors, wherein the high frequency electromagnetic field induces
eddy currents in the respective susceptor element generating an
impulse of heat that is emitted by the susceptor element, which
impulses of heat seal the edge region of the walls to the
attachment portion of the fitment and to each other.
[0167] In an embodiment of the fourth aspect of the invention the
inductor comprises an elongated inductor section that extends along
the respective contoured front surface at the rear side of the
respective at least one susceptor element.
[0168] The fitment sealing station in the fourth aspect of the
invention may be embodied with details as described herein with
reference to the first aspect of the invention, including one or
more of the optional and/or preferred details thereof, e.g. as
stated in the appended claimset.
[0169] The fourth aspect of the invention also relates to a
production machine configured for use in the method.
[0170] Embodiments of the pouch production according to the
invention will be described by way of example only, with reference
to the accompanying drawings. In the drawings:
[0171] FIG. 1 schematically shows a view in perspective of an
embodiment of the pouch production according the invention,
[0172] FIG. 2 schematically shows an example of a spout to be
joined between two opposed film material walls of a pouch,
[0173] FIG. 3 schematically shows a top portion of a pouch provided
with the spout of FIG. 2,
[0174] FIG. 4 schematically shows an embodiment of the sealing
device according to the invention,
[0175] FIG. 5 schematically shows the susceptor element and
inductor of FIG. 4,
[0176] FIG. 6 schematically shows a cross section of a jaw
including the susceptor element and inductor,
[0177] FIG. 7 schematically shows a cross section of a jaw
including the susceptor element, inductor, and resilient backing
layer of the susceptor element,
[0178] FIGS. 8A,B, C schematically shows the electromagnetic field
generated by the jaw of FIG. 4 and the interaction with the
susceptor element,
[0179] FIG. 9 shows an alternative design of the inductor,
[0180] FIG. 10 shows yet another alternative design of the
inductor,
[0181] FIG. 11 illustrates schematically the operation of a
continuous motion sealing device.
[0182] FIG. 1 schematically depicts a pouch production machine and
related operating method according to the invention for the
production of collapsible pouches made from heat-sealable film
material. Throughout the figures, the pouch production machine is
referred to with reference numeral 1.
[0183] The pouch production machine 1 is configured to produce
collapsible pouches 100 comprising a plastic spout 150 or other
fitment, e.g. standing collapsible pouches. The spout 150 is
pre-made, e.g. by injection molding.
[0184] The pouch production machine 1 has a frame (not shown)
provided with a film supply device 10 that is adapted to receive
one or more rolls 11 of flexible heat-sealable film material 12. In
the pouch production system 1, the film material 12 is unwound from
the roll 11.
[0185] The pouch production machine 1 comprises a folding device 13
to fold the film material 12 dispensed from a single roll into a
folded shape.
[0186] In the depicted exemplary embodiment, the folded film
material 12 travels downward in a vertical direction (V). In
another design the folded film material could travel
horizontally.
[0187] The folding device 13 is configured to fold the film
material 12 such, that a fold-line is provided on one, here
vertical, side of the folded film material 12. By means of the fold
line, the film material 12 is formed into a first pouch wall 101
and an opposed second pouch wall 102, in order to define an
interior of the pouch 100 in between them. In another embodiment
the film material is folded into a gusset, e.g. to form a gusset
bottom or a side gusset of the pouch.
[0188] After folding, the film material travels along a first heat
sealing device 20. The first heat sealing device 20 is aligned
parallel to the vertical direction (V) and is aligned with outer
side seam regions of the folded film material 12, being located
opposite to the fold line.
[0189] The first heat sealing device 20 is configured to weld the
vertical seam regions of the pouch walls 101, 102 that are located
opposite to the fold line, such that the film material 12 attains a
flattened tubular shape.
[0190] Downstream of the first heat sealing device 20, here just
below the device 20, the pouch production machine 1 comprises a
second heat sealing device 21. The second heat sealing device 21 is
aligned perpendicular to the vertical direction (V), e.g. parallel
to a horizontal direction (H).
[0191] The second heat sealing device 21 extends across the width
of the folded film material 12 and is configured to weld a bottom
seam of the pouches 100 to be made.
[0192] The pouch production system 1 comprises a film conveyance
device 30 configured to move the folded film material 12 in the
direction (V) along the first heat sealing device 20 and
subsequently along the second heat sealing device 21.
[0193] A cutting device 14 is provided to separate a pouch 100 from
the folded film material 12 by making a horizontal cut across the
width of the folded and now sealed film material. The cut extends
close to the bottom seam, so that the individualised pouch 100 has
a non-bonded upper edge.
[0194] In the depicted embodiment, the film conveyance device 30
moves the folded film material in a stepwise manner along the
stationary first and second heat sealing devices 20, 21. At the
relevant position in front of the first heat sealing device 20, the
film material 12 is held to form the first weld opposite to the
fold line. Simultaneously, the film material 12 is held at a
relevant location in front of the second heat sealing device 21 to
form the second weld at the bottom of the pouch 100.
[0195] In an embodiment one or more of the first heat sealing
device 20 and the second heat sealing device 21 comprises a first
jaw and a second jaw for heat sealing the material 12.
[0196] The production machine 1 is embodied with a horizontal
conveyance mechanism 40 that is configured to convey individual
pouches 100 along a path of conveyance, wherein the sealing station
E'' as discussed herein as well as one or more other stations A, B,
C, D, E' are arranged along this path of conveyance. The depicted
conveyance mechanism is configured and operated to convey in an
intermittent motion pattern, so stepwise. Often a so-called walking
beam conveyance mechanism is employed for stepwise conveyance. The
sealing action is then, concurrently with one or more other
activities at one or more other stations of the machine 1,
performed with the pouch 100 at rest.
[0197] The sealing station E'' is mounted stationary in the machine
1, at least with regards to the direction of conveyance.
[0198] The mechanism 40, for example, is a walking beam mechanism
having pairs of grippers 41 in a horizontal array. Herein each pair
of grippers 41 is embodied to grip opposed side or corner regions
of the pouch, with the open top directed upwards. The pair of
grippers 41 is actuable in this example, allowing the spacing
between the grippers 41 to be altered for opening and closing of
the open top region of the pouch.
[0199] Below the cutting device 14 an individualized pouch 100 is
gripped by a set of grippers 41.
[0200] At station A of the machine 1, grippers 41 are moved towards
one another, to open the top of the pouch 100, more specifically to
open the non-bonded upper edge.
[0201] At station B, an opener 15 is introduced into the top of the
pouch 100 to further open the non-bonded upper edge of the pouch
100.
[0202] Station C is a filling station, where a product, e.g. a
liquid and/or solid product, is filled into the pouch 100 by a
filling device 16 via the non-bonded upper edge.
[0203] At station D, the grippers 41 are moved away from one
another, to somewhat close the non-bonded upper edge of the pouch
100 after the filling.
[0204] Station E is, at least in the present embodiment, a combined
spout inserting station E' where a spout inserting device 50 is
adapted to insert an attachment portion of a spout 150 in the
non-bonded edge region, and a spout sealing station E''.
[0205] Before we address the spout sealing station E'' we will
first discuss the exemplary embodiment of the plastic spout 150
which is depicted in more detail in FIGS. 2 and 3.
[0206] The plastic spout 150 has an attachment portion 151 with
thin sealing walls 152,153 that depend from a transverse wall 154
of the spout body. The spout 150 further comprises a tubular neck
155 extending upwards from the transverse wall 154 and forming a
product passage for the dispensing of product from the pouch 100
via a mouth.
[0207] The sealing walls 152, 153 may have a thickness of less than
2 mm in practical embodiments.
[0208] Preferably, as shown, the sealing walls 152, 153 are smooth
on their sealing faces, so lacking any relief that keeps the film
material locally away from the sealing wall in the desired region
of the join.
[0209] As discussed a closure, e.g. a cap, may be mounted on the
spout 150, e.g. after the filling or in the form of a pre-assembly
of the spout 150 and the closure.
[0210] Instead of a spout 150 another fitment may also be
contemplated in the context of the present invention.
[0211] FIG. 3 depicts the situation wherein the spout 150 has been
sealed in the upper edge region of the spout at station E''. Herein
the entire upper edge region has been sealed in one sealing cycle
along with sealing the spout 150 to the pouch.
[0212] Herein, reference numeral 110 indicates the fold line,
forming a vertical side of the pouch 100 in this example. Reference
numeral 111 indicates the side seam of the pouch 100 made by
station 20.
[0213] Reference numerals 101 and 102 indicate the opposed first
and second walls of the pouch 100.
[0214] Reference numeral 113a indicates a portion of the top seam,
and reference numeral 113b another portion of the top seam.
Reference numeral 113c indicates the part of the top seam where the
spout 150 is received and sealed.
[0215] In FIG. 4, an embodiment of an spout sealing station E'' is
displayed schematically in more detail, partially in exploded-view
along with the pouch 100 and spout 150 that has already been sealed
in the upper edge region thereof.
[0216] The spout sealing station E'' comprises: [0217] an impulse
sealing device comprising a first jaw 210 and a second jaw 220,
[0218] an actuator device, here with actuator 201 for jaw 210 and
actuator 202 for jaw 220, configured to move the first and second
jaws 210, 220 relative to one another between an opened position
and a clamped position, [0219] a cooling device 300 configured to
cool each of the first and second jaws 210, 220.
[0220] The first jaw 210 has a first contoured front surface
configured to contact the edge region of a respective first wall
101 of the pouch.
[0221] The second jaw 220 has a second contoured front surface
configured to contact the edge region of a respective second wall
102 of the pouch.
[0222] The first and second contoured front surfaces each have a
recessed face portion defining a recess R configured to receive
therein a half of the attachment portion 151 of the spout 150.
[0223] The first and second contoured front surfaces each define,
on opposite sides of the respective recessed face and adjoining
said recessed face, coplanar face portions.
[0224] Each of the first and second jaws 210, 220 comprises at the
respective contoured front surface thereof one single elongated,
impulse heatable member 212, 222 that extends along the recessed
face portion and the coplanar face portions of the respective front
surface and that is covered by a heat-resistant non-stick covering
(not shown in FIG. 4 for clarity).
[0225] The sealing station E'' is configured to perform an impulse
sealing cycle as discussed herein, so that the spout 150 is sealed
in the upper edge region and, as preferred, the entire upper edge
region of the pouch 100 is hermetically sealed.
[0226] In the cycle, the actuator device 201, 202 is configured to
bring the first and second jaws 210, 220 into the clamped position,
so that--in the edge region--the first and second walls 101, 102
are clamped against the attachment portion 151 by the recessed
faces of the first and second jaws and so that--in the edge
region--the first and second walls 101, 102 on opposite sides of
the spout 150 are clamped against one another by the coplanar faces
of the first and second jaws 210, 220.
[0227] Each impulse heatable member is a susceptor element 212, 222
comprising electrically conductive material. Each susceptor element
has a rear side facing away from the respective contoured front
surface of the jaw.
[0228] Each of the first and second jaws 210, 220 comprises an
inductor 211, 221 which is electrically insulated from the
respective susceptor element 212, 222. The inductors each comprises
an elongated inductor section, here one pair of inductor sections,
that extends along the respective contoured front surface at the
rear side of the respective susceptor element.
[0229] The sealing station E'' further comprises a high frequency
alternating electric current source 250, which is connected to the
inductor 211, 221 of each of the first and second jaws 210, 220. In
an embodiment, both the inductors 211, 212 are connected to one and
the same source 250.
[0230] The sealing station E'' is configured to perform an impulse
sealing cycle. Once the jaws 210, 220 have been moved into the
clamped position as indicated above, the electric current source
250 is operated to temporarily feed a high frequency electric
current to the inductors 211, 221. This generates a high frequency
electromagnetic field by means of the inductors. In turn the high
frequency electromagnetic field induces eddy currents in the
respective susceptor element 212, 222 generating an brief and
vehement impulse of heat that is emitted by the susceptor element
212, 222. These impulses of heat seal the edge region of the walls
101, 102 to the sealing faces of the attachment portion 151 and to
each other in the portions 113a, b of the upper edge region.
[0231] So the station E'' temporarily energizes the susceptor
elements 212, 222 on the basis of induction, so as to generate an
impulse of heat that is emitted by each of the elements 212,
222.
[0232] The first and second jaws 210, 220, at least the susceptor
elements 212, 222 thereof, cool down after termination of the
energizing assisted therein by operation of the cooling device
250.
[0233] The actuator device 201, 202 is configured to move the first
and second jaws 210, 220 into the opened position after the cooling
down has taken place in satisfactory manner.
[0234] It is shown in FIGS. 4 and 5, that in each jaw 210, 220
there is just one pair of elongated inductor sections 221a, b that
are parallel to one another and vertically spaced from one another
by a horizontal slit 221c. The pair of inductor sections is
arranged in proximity of the rear side of the susceptor
element.
[0235] In an embodiment, the elongated inductor section 221a, b is
made from a metal, e.g. of copper.
[0236] It is shown in FIGS. 4 and 5, that the at least one
elongated inductor section 221a,b is a solid cross-section metal or
other, preferably high conductivity material inductor section, e.g.
made of copper which is preferred. This arrangement allows to avoid
undue variations of current density within the inductor section,
and thereby undesirable variation in the generated field, e.g.
compared to an internally hollow inductor section.
[0237] It is shown in FIGS. 4 and 5, that the at least one
elongated inductor section 221a,b has a constant cross-section,
preferably a solid cross-section, over its length along the
contoured front surface of the respective jaw. This design avoids
undue variations of current density within the inductor section,
which might otherwise occur at locations where the cross-section
changes, and thereby undesirable variation in the generated
field.
[0238] It is shown in FIGS. 4 and 5, that the uniform cross-section
elongated inductor section 221a, b has, seen in a top view onto the
jaw, a shape corresponding to the contoured front surface of the
jaw and maintains a uniform distance between the susceptor element
222 and the elongated inductor section 221a,b. This arrangement
enhances uniformity of the development of heat in the susceptor
element.
[0239] In alternative embodiments, the inductor may have a
non-constant cross-section, for example locally having a
cross-section that is narrower than a nominal cross-section, to
increase locally the current density for the high-frequency
electric current, in order to locally increase the intensity of the
heat impulse emitted by the susceptor element.
[0240] In embodiments, the distance between the inductor and the
susceptor element may locally vary from the uniform, e.g. nominal
distance between the inductor and the susceptor element. With a
distance that is locally narrower, for example, the electric
magnetic field in the susceptor is increased locally, in order to
locally increase the intensity of the heat impulse emitted by the
susceptor element.
[0241] The horizontal slit 221c can be air slit or a slit filled
with electrically insulating material.
[0242] In embodiments, said slit 221c between neighbouring inductor
sections 221a, b that are arranged above one another has a height
between 0.01 and 5 mm, more preferably between 0.1 and 2 mm.
[0243] The presence of the slit 221c between the parallel elongated
inductor sections 221a, b allows for a desirable concentration of
the field that is generated by the inductor of the jaw onto the
susceptor element 222. This is illustrated in FIGS. 8A,B, and
C.
[0244] FIG. 8B illustrates the strength and distribution of the
field when seen from above onto the front of a jaw, wherein the
field is indicate with FLd and is shown in relation to the inductor
221 and susceptor 222.
[0245] FIG. 8C illustrates the strength and distribution of the
field of FIG. 8B in a perspective view.
[0246] As explained herein, the field is fairly homogenous, which
enhances homogeneity of the impulse heating of the susceptor 222
and thereby the quality and reliability of the sealing process. In
particular, undue variations in temperatures to which the film
material is subjected are avoided, which would otherwise arise if
the field were irregular.
[0247] It is shown in FIGS. 4 and 5, that the susceptor element 222
extends, seen in a view onto the front surface of the jaw, over the
horizontal slit 221c between the parallel inductor sections
221a,b.
[0248] It is shown in FIGS. 4 and 5, that the susceptor element
222, seen in a view onto the front of the jaw, extends over the
slit 221c between parallel elongated inductor sections 221a,b and
overlaps in said view with each of the parallel inductor
sections.
[0249] It is shown in FIGS. 4 and 5, that the susceptor element 222
is embodied as one strip that extends over the slit 221c between
parallel elongated inductor sections 221a,b and overlaps in said
view with each of the parallel inductor section.
[0250] It is shown in FIGS. 4 and 5, that a strip shaped susceptor
element 222 has an upper edge and a lower edge defining a height of
the strip, wherein the height of the strip is at least 50% of the
height of the single pair of inductor sections 221a, b including
the slit 221c that are arranged at the rear of the strip above one
another, e.g. between 75% and 125% of said height, e.g. about 100%
of said height.
[0251] It is shown in FIGS. 4 and 5, that a strip shaped susceptor
element 222 has an upper edge and a lower edge defining a height of
the strip, wherein the inductor of a jaw comprises a number of,
e.g. multiple, inductor sections 221a, b that each extend along the
rear side of the susceptor element. Herein the height of the strip
is preferably at most the same as the height of the number of one
or more inductor sections, preferably the upper edge and the lower
edge of the strip not protruding above and below the height of the
one or more inductor sections.
[0252] It is shown in FIGS. 4 and 5, that the inductor of a jaw is
embodied so that in a pair of adjacent and parallel inductor
sections 221a, b arranged at the rear side of the susceptor element
222, the current flows in opposite directions through the inductor
sections.
[0253] It is shown in FIGS. 4 and 5, that the inductor of a jaw
comprises a C-shaped inductor element having parallel first and
second inductor sections interconnected at one axial end of the
inductor, e.g. by a connecting portion 221d integral with the
inductor sections, in series, wherein the free ends of the inductor
sections have terminals for electrical connection to the current
source. The connection portion 221d is, as preferred, located
outside the region where the susceptor element 222 is located, as
the connector portion 221d is likely to show irregular field
effects that might lead to non-homogeneity of the heating of the
susceptor element.
[0254] It is shown in FIG. 4, that the first and the second jaws
are each provided with one C-shaped inductor element, having
parallel first and second inductor sections interconnected in
series, wherein the free ends of the inductor sections have
terminals for electrical connection to the current source 250.
[0255] It is shown in FIGS. 4 and 5, that the inductor of a jaw
comprises a C-shaped inductor element having parallel first and
second inductor sections 221a,b interconnected in series and
arranged above one another, wherein the inductor sections are
separated by a horizontal slit 221c, e.g. an air slit or a slit
filled with electrically insulation material.
[0256] It is shown in FIGS. 4 and 5, that the inductor of a jaw
comprises multiple, e.g. just two, elongated inductor sections
221a,b arranged parallel to one another and arranged above one
another behind the susceptor element 222.
[0257] In an embodiment the at least one elongated inductor section
221a, b has a thickness "t" of between 1.0 and 4.0 mm, seen
perpendicular to the front surface of the jaw, for example between
1.5 and 3.0 mm. The limited thickness of the inductor element
enhances the cooling of the jaw, including the inductor of the jaw,
e.g. as one or more cooling fluid ducts are preferably arranged in
proximity of a rear side of the at least one inductor element.
[0258] In an embodiment the at least one elongated inductor section
has a rectangular cross-section with a height "h" that is greater
than the thickness "t" of the inductor section. This arrangement
allows to limit the thickness, which allows for efficient
cooling.
[0259] It is shown in FIGS. 4 and 6, that each jaw may be provided
with one or more cooling fluid ducts 214, e.g. the cooling fluid
being a cooling liquid, e.g. water, being passed through the
cooling fluid ducts, e.g. using a pump assembly 215, e.g. a cooling
liquid circuit being a closed circuit including a heat exchanger
216 configured to remove heat from the cooling liquid.
[0260] Preferably, no cooling fluid is passed in a region between
the inductor and the susceptor as that would unduly increase the
distance between them and would impair effectivity of the impulse
heating induced by the field. It will be appreciated, that in view
of the desired very close proximity of the susceptor element to the
front surface of the jaw, there is in practice no space for any
cooling duct in said region. So, in practical embodiments, cooling
of the jaw is preferably done using a control flow of cooling
fluid, e.g. liquid, through one or more ducts that are arranged
behind, and preferably in close proximity to, the inductor
sections.
[0261] In an embodiment, at least one cooling fluid duct 214
extends along the at least one inductor section 221a, b that
extends along the rear side of the susceptor element 222.
[0262] It is preferred for the machine 1 to be configured such that
cooling of the jaws 210, 220 is active during the entire impulse
sealing cycle, so also during the creation of the heat impulse
which happens so fast that it is generally not impaired by the
cooling. In another configuration the cooling may be interrupted or
reduced around the moment of the heat impulse.
[0263] The cooling of the jaws 210, 220 may, as preferred, be
configured to cause cooling of the heat-sealed edge region before
the jaws 210, 220 are opened, e.g. the film material and fitment
150 in the fused region being cooled to below 60.degree. C. before
opening, e.g. to below 40.degree. C.
[0264] A benefit of the cooling is that, before the release from
the jaws 210, 220, the sealed region of the pouch 100 will acquire
a strength and rigidity that is greater than in absence of such
cooling. This, for instance, may allow for an increased production
speed of the machine 1 wherein higher forces may be exerted on the
walls of the pouch 100, e.g. in view of transport of the pouch or
string of interconnected pouches through the machine. Undue
stretching of the pouch, e.g. in the area of the fitment seal, is
preventable to a large degree by use of the invention disclosed
herein.
[0265] In an embodiment, the susceptor element 212, 222 is made of
metal material, e.g. a metal or a metal alloy, e.g. of a thin metal
strip.
[0266] For example, the susceptor element 212, 222 is made of, or
comprises, aluminium, nickel, silver, stainless steel, molybdenum
and/or nickel-chrome.
[0267] It is shown in FIGS. 4 and 5, that the susceptor element
212, 222 is embodied as a strip having opposed front and rear main
faces that define the thickness of the strip between them. In an
embodiment, the thickness of the susceptor element strip 212, 222
is constant over the extension of the strip.
[0268] In embodiments, the thickness of the susceptor element may
differ locally from a nominal thickness. For example, the susceptor
element may comprise a thickened portion at its rear surface, e.g.
facing away from the front surface of the jaw, to locally increase
the intensity of the electromagnetic field in the susceptor
element, in order to locally increase the intensity of the heat
impulse that is emitted by the susceptor element.
[0269] It is shown in FIGS. 4 and 5, that the susceptor element
212, 222 is embodied as a planar strip, most preferably the jaw
having a single planar strip susceptor element. This arrangement as
a planar strip is in particular preferred for the handling of
plastic fitments that have an attachment portion with planar and
preferably smooth sealing faces.
[0270] It is shown in FIG. 4, that the plane of the susceptor
element 212, 222 is parallel to the plane of the sealing face of
the attachment portion 151. The preferred smoothness of the sealing
faces 152,153 of the portion 151, so the absence of a relief that
locally holds the wall of film material away from the sealing face
and creates air pockets between the wall 101, 102 and the sealing
face, causes a very effective transfer of the heat impulse from the
jaw 210, 220 to the zone where the joint is made. In practice it
can be observed that a joint is achieved through the entirety of
the area where the susceptor 212, 222 emits heat towards the
sealing face of the attachment portion.
[0271] It is shown in FIGS. 4 and 5, that the susceptor element
212, 222 is a strip, e.g. of a metal, e.g. of aluminium, wherein
the height of the strip is between 3 and 10 millimetres, e.g.
between 4 and 8 millimeters. It is shown in FIG. 4, that the strip
has a constant height over its length.
[0272] In an alternative embodiment, the height of the susceptor
element may be non-constant. For example, a lower edge of a
susceptor element in a jaw of a fitment sealing station may be
upwardly curved in a central, e.g. at a part that is configured to
abut an attachment portion of a fitment during use, to effect that
lees heat is transferred to a lower edge of the attachment portion
and the air below. This improves the rate at which the seal can be
cooled, since the air would otherwise act as an insulator, e.g.
reducing the cooling rate.
[0273] It is shown in FIGS. 4 and 5, that the susceptor element
212, 222 strip lacks apertures over its extension.
[0274] It is shown in FIGS. 4 and 5, that the jaws 210, 220 are
each provided with a single continuous susceptor element 212, 222
embodied as a strip, e.g. of metal.
[0275] It is shown in FIGS. 4 and 5, that the susceptor element
222, e.g. embodied as a strip, has a thickness of between 0.01 and
5 mm, preferably between 0.05 and 2 mm, more preferably between
0.08 and 0.8 mm, e.g. of between 0.08 and 0.5 mm. In general, it is
considered desirable to have a minimum thickness of the susceptor
element in view of the desire to rapid cool the jaw, including the
inductor and the susceptor, after termination of the heat impulse.
A thin design of the susceptor, contributes to this desire. It is
noted that, in contrast to the impulse sealing device addressed in
the introduction, no electric current from a current source is
passed through the susceptor, so the cross-section need not be
designed to deal with such a current flow.
[0276] It is shown in FIGS. 4 and 5, that the jaw is provided with
a single continuous susceptor element 222 embodied as a strip, e.g.
of metal, having a height of the strip between 3 and 10
millimetres, e.g. between 4 and 8 millimeters, and a thickness of
between 0.08 and 0.8 mm, e.g. of between 0.08 and 0.5 mm. For
example, the strip is made of aluminium material.
[0277] In embodiments, the frequency of the electric current
supplied by source 250 to the inductors 211, 221 of the jaws 210,
220 is between 100 kHz and 1 MHz, for example between 250 KHz and
750 KHz.
[0278] In embodiments, the magnitude of the electric current
supplied by source 250 to the inductors 211, 221 of the jaws 210,
220 is between 20 A and 600 A.
[0279] In embodiment, the electric current is supplied by source
250 to the inductors 211, 221 of the jaws 210, 220 at a voltage
with a magnitude between 40 V and 500 V.
[0280] It is shown in FIGS. 4 and 8A-C, that a jaw 210, 220 is
embodied such that the high frequency electromagnetic field
generated by the inductor 211, 221 primarily causes the very rapid
development of heat within a frontal skin layer of the susceptor
element 212, 222 due to the so-called skin effect. The skin effect
is the tendency of an alternating electric current to become
distributed within a conductor such that the current density is
largest near the surface of the conductor and decreases,
exponentially, with greater depths of the conductor. At high
frequencies the skin depth becomes smaller. This depth may, for
example, be 0.15 mm for an aluminium susceptor element if the
frequency of the field is 350 KHz. The thickness of the susceptor
element is envisaged to be more than this skin depth, yet not too
much for the reason addressed herein.
[0281] It is shown in FIG. 4, that the spacing between the rear of
the susceptor element 212, 222 and the neighbouring inductor
section(s) is at a minimum 0.025 mm, or 0.05 mm, or 0.1 mm and at a
maximum 3.0 mm, or 2.0 mm, or 1.0 mm. The minimum values of this
spacing are primarily envisaged to allow for effective electrical
insulation between the inductor section(s) on the one hand and the
susceptor element on the other hand. In embodiments, it is
envisaged that this spacing is only filled with electrically
insulating material. The maximum value of this spacing is primarily
envisaged to have the inductor section(s) in close proximity to the
rear of the susceptor element, wherein a maximum of 1.0 mm is
preferred. In a practical embodiment this spacing may be 0.05 mm.
So this spacing may in practical embodiments be less than the
thickness of the susceptor element itself.
[0282] Preferably, the entire spacing between the rear of the
susceptor element and the neighbouring inductor section(s) is
filled with electrically insulating material.
[0283] FIG. 6 illustrates that the spacing between the rear of the
susceptor element 222 and the neighbouring inductor section 221 is
filled with one or more layers of electrically insulating tape, for
example at least a layer of Kapton 223 and a layer of Teflon 224,
for example just one layer of Kapton tape and one Layer of Teflon
tape.
[0284] In an embodiment the electrical insulation between the rear
of the susceptor element and the neighbouring inductor section(s)
has a thickness of between a minimum of 0.025, or 0.050, or 0.1 mm,
and a maximum of at most 3.0 mm, or 2.0 mm.
[0285] In an embodiment the anti-stick layer 226 at the front of
the jaw is embodied as a layer of Teflon tape. In another
embodiment the anti-stick layer could comprises glass or the
like.
[0286] FIG. 6 illustrates that the front face of the susceptor
element 22 is covered by at least one layer of electrically
insulating material 227, e.g. Kapton, e.g. Kapton tape, e.g. having
a thickness of between 0.01 and 0.05 mm, e.g. of about 0.025
mm.
[0287] In an embodiment the spacing between the front surface of
the jaw and the susceptor element is at a minimum 0.025 mm, or
0.050 mm, and at a maximum 2.0 mm, or 1.0 mm, or 0.5 mm. Herein,
the minimum spacing may be governed by the presence of an
anti-stick layer 226. The anti-stick layer can be coated onto the
jaw, e.g. onto the susceptor element, e.g. a glass or Teflon
coating.
[0288] In an embodiment, the spacing between the front surface of
the jaw and the susceptor element is filled with at least one, e.g.
multiple layers of electrically insulating material, e.g. tape, for
example at least a layer of Kapton tape 227 and a layer of Teflon
tape 226 as anti-stick layer forming the front surface of the jaw,
for example just one layer of Kapton tape and one Layer of Teflon
tape.
[0289] It is shown in FIGS. 4 and 5, that the contoured front
surface of the jaws 210, 220 is smooth in a region of contact with
the walls 101, 102 of film material, so lacking any relief that
would locally keep the film material away from the front surface,
so lacking for example one or more ribs, bosses, etc. This
arrangement is preferred in conjunction with a smooth design of the
sealing faces 152, 153 of the attachment portion 151. Preferably,
the smooth region of contact of the front surface of the jaws is
designed to be parallel to the sealing surface of the attachment
portion 151 that is to be joined to the walls of film material.
[0290] It is shown in FIG. 4, that the jaws 210, 220 are
configured, e.g. have a length, so that the entire non-bonded edge
region in which the spout 150 is inserted, e.g. by an inserter 50
of the machine 1, is sealed in one cycle by the operation of the
jaws. So both the spout 150 is secured in the edge region and the
entirety of the edge region is sealed closed. This avoids the needs
for additional sealing actions along said edge region.
[0291] It is shown in FIG. 4, that the recessed face portion of
each jaw 210, 220 is curvaceous over its entire longitudinal
extension.
[0292] It is shown, that both jaws 210, 220 have a main body 220a,
e.g. of plastic or ceramic material, e.g. a heat-resistant
material, e.g. of PEEK, on which the susceptor element and the
inductor are mounted. The plastic or ceramic material is selected
to not impair the field that is generate by the inductor, at least
not in an undesirable manner. Boron nitride and/or Aluminium
nitride, Polyphenylene sulphide (PPS), vulcanized silicone
materials can be considered as well for the main body. In
particular Boron nitride may provide for a good thermal
conductivity, thereby enabling a good conductivity of heat from the
susceptor element towards the cooling device, e.g. towards the
cooling fluid.
[0293] One or more cooling ducts 214 are provided, e.g. machined,
in a main body, e.g. of PEEK.
[0294] For example, one or both jaws 210, 220 have a main body,
having a main body front side into which one or more grooves are
made in which the one or more induction sections are arranged. In
embodiments the susceptor element is arranged over the main body
front side, as discussed herein relative to the one or more
inductor sections. Herein, one or more layers of electrically
insulation material are arranged between the inductor section(s)
and the susceptor elements, e.g. of Kapton and/or Teflon. One or
more further layers of electrically insulation material as well as
an outer anti-stick covering are mounted over the susceptor element
to from the front surface of the jaw.
[0295] In embodiment, the sealing device of station E'' is
configured to generate a heat impulse with the susceptor elements
212, 222 of between at least 150.degree. C. and at most any of
200.degree. C., 300.degree. C., 400.degree. C., or 500.degree. C.
measured on the susceptor element.
[0296] In an embodiment, the heat impulse duration lies between 10
and 1000 milliseconds, e.g. between 20 and 500 milliseconds, e.g.
between 75 and 400 milliseconds.
[0297] In an embodiment the cycle includes a clamped cooling phase
directly following the heat impulse during which the jaws 210, 220
are maintained in clamped position, which clamped cooling phase may
have a duration between 200 and 800 milliseconds, e.g. between 300
and 600 milliseconds.
[0298] It is noted that control of the temperature that is reached
during the impulse heating may be done on the basis of monitoring
and controlling the supply of electrical power to the inductors
and/or by monitoring and controlling the temperature and/or flow
rate of cooling fluid, e.g. water, e.g. water at more or less
ambient temperature, circulated along the respective jaws.
[0299] The production machine 1 is primarily envisaged for
production of pouches from metal-free film material. For example,
the film material of the walls is a multi-layer material where one
and the same plastic, but with different properties, is found in
all layers. In another embodiment the wall is a monolayer wall. The
absence of a metal layer allows for more effective recycling.
[0300] FIG. 7 illustrates that in case of a pouch with one or more
side gussets, the edge region where the fitment is to be mounted
may include a so-called triple point. In such a situation it can be
advantageous to provide a resilient backing layer 228, e.g. of
vulcanized silicone rubber and/or Teflon, behind the susceptor
element 222, thereby allowing for the jaw front to accommodate for
a local variation of the number of film material walls. For
example, the resilient layer 228 has a thickness between 0.1 and
2.0 millimeter. Herein it is understood that the thin susceptor
element 222 is able to flex so as to accommodate the local
variation in the number of walls.
[0301] FIG. 9 shows an embodiment, wherein the inductor 221' of a
jaw has an inductor element that is generally U-shaped seen from
above.
[0302] Herein each leg of the U-shape, preferably at least the
front leg behind the susceptor element 222, is embodied with
multiple elongated inductor sections 221a, b as discussed as well
as slit 221c. For reasons of homogeneity of the generated field the
other or rear leg is preferably similar to the front leg. The
portion 221d now is a curve seen from above.
[0303] The shape corresponds to the contoured front surface of the
respective jaw when seen in said view from above.
[0304] FIG. 10 shows an embodiment, wherein the inductor 221'' has
a single elongated inductor section behind the susceptor element
222.
[0305] FIG. 10 also illustrates that the inductor 221 of a jaw has
an inductor element that is generally U-shaped seen from above
wherein at least the front leg of the U-shape, preferably both legs
as shown, has a shape corresponding to the contoured front surface
of the respective jaw when seen in said view from above.
[0306] In FIG. 11, the impulse sealing of top edge regions of a
first pouch wall 101 and of a second pouch wall 102, with a spout
150 in between them, is displayed schematically by means of steps
(a)-(e).
[0307] In the displayed embodiment, the sealing device 200
comprises a first jaw 210 and a second jaw 220. During the
production of the pouches, the pouch walls 101, 102 are moved
continuously in a transportation direction (T), from left to right
in FIG. 11. The welding device 200 is configured to move along with
the pouch walls 101, 102 in the transportation direction (T), at
least during the sealing cycle.
[0308] The cycle is started with step (a), shown on the left side
of FIG. 11. The first jaw 210 and the second jaw 220 are initially
in a position spaced from the pouch walls 101, 102 that are opened
in in upper region, with the spout 150 being inserted with its
attachment portion in this opened upper region.
[0309] Upon operation of the first actuator device 201, the first
jaw 210 is moved towards its first contact position, such that the
first jaw 210 comes in contact with the first pouch wall 101.
Similarly, the second jaw 220 is moved towards its first contact
position by the second actuator device 202, such that the second
jaw 220 comes in contact with the second pouch wall 102. In the
respective contact positions, the first front surface abuts the
first pouch wall 101 and the second front surface abuts the second
pouch wall 102. Furthermore, the spout 150 is now clamped, lightly
as no pressure is involved in the sealing process, in between the
first pouch wall 101 and the second pouch wall 102 and within the
recesses R.
[0310] Next, during step (b), the jaws 210, 220 remain in their
respective clamped positions and move along with the pouch walls
101, 102. Step (b) is an impulse sealing step, during which an
electromagnetic field is provided in the first inductor 211 and in
the second inductor 221, in order to induce respective heat
impulses in the first susceptor 212 and in the second susceptor
222.
[0311] Under the influence of the heat impulses, the first pouch
wall 101 and the second pouch wall 102 are locally fused with each
other and with the spout 150 in between them, in order to heat seal
the pouch walls 101, 102 to the spout attachment portion 151 and to
fuse the pouch walls 101, 102 against each other next to the
portion 151.
[0312] During step (c), the heat impulses are no longer provided as
the inductors are no longer energized, but the jaws 210, 220 remain
in their clamped positions. Cooling fluid is being circulated
through the ducts 214 in the jaws 210, 220. Preferably, this supply
of cooling fluid may be continued during all steps (a)-(e) of the
process. Accordingly, heat is removed from the welded pouch 100 as
well.
[0313] During step (d), the first jaw 210 and the second jaw 220
are moved away from each other, into the opened position. As such,
the welded pouch 100 may be taken over by a further handling
device, to allow for further processing thereof, such as packaging.
Upon moving them away from each other, the jaws 210, 220 again
become spaced.
[0314] Finally, during step (e), the first jaw 210 and the second
jaw 220 are moved back towards their initial position. This
movement may take place in a direction opposite to the
transportation direction (T), in order to effect that the jaws 210,
220 become arranged in their initial positions, similar as on the
onset of step (a).
[0315] After moving the jaws 210, 220 back during step (e), the
cycle is repeated, starting with step (a) again.
[0316] It will be appreciated that the path of the jaws 210, 220
can be of any suitable shape, e.g. circular, oval, linear, etc.
* * * * *