NL2023585B1

NL2023585B1 - Production of collapsible pouches

Info

Publication number: NL2023585B1
Application number: NL2023585A
Authority: NL
Inventors: Sáez López Abel; Last Laurens; Wilhelmus Van Tuil Johannes
Original assignee: Bossar Holding B V
Priority date: 2019-07-29
Filing date: 2019-07-29
Publication date: 2021-02-22

Abstract

The present invention relates to a production machine for the production of collapsible standing pouches, which comprises an impulse sealing device with a firstjaw and a second jaw for contacting bottom gussets of walls of the pouches. Each jaw comprises a susceptor element comprising electrically conductive material, having a front surface that is at least shaped as an inverted T for sealing side edges and at least a portion of bottom edges of two adjacent interconnected pouches. Each jaw comprises an inductor which is electrically insulated from the respective susceptor element. The machine comprises a high frequency electric current source, which is connected to the inductors. The machine is configured so that, in an impulse sealing cycle for sealing the bottom gussets of the pouch walls, 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. 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 bottom gussets of the pouch walls to each other.

Description

P34195NL00

PRODUCTION OF COLLAPSIBLE POUCHES The present invention relates to the production of collapsible pouches. For the production of collapsible pouches it is known to make use of a production machine having a sealing station that is configured to heat seal bottom gusset portions of two adjacent pouches in a string of interconnected pouches made from heat-sealable film material, e.g. to form the bottom of a standing pouch.

In a well-known embodiment the 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 front surface configured to contact the bottom region of a respective first or second wall of the pouches. The front surfaces of the jaws each define planar face portions. The jaws of the known 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 continuously heated jaws are moved into the clamped position, having the pouch walls in between the jaws. 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.

In view of the conditions during this common practice type of heat sealing bottom gusset portions of pouches, several developments have been made over the years. For example, JP2007245486 discloses a pouch production system that comprises continuously heated jaws for sealing a bottom gusset area of pouches. The jaws in this document have a shape that corresponds to the contour of the gusset weld in the pouch, extending from a lower edge of the pouch to a height above the gusset. During sealing with these jaws, the triple point of the pouch may be sealed as well.

In JP2007245488, it is further disclosed that during the sealing of interconnected pouches, the string of interconnected pouches is positioned in between the first jaw and the second jaw. The heated jaws thereby project partially over bottom gussets of two adjacent pouches. During sealing, the jaws are configured to simultaneously seal a part of the bottom gusset of the first pouch and to seal a part of the bottom gusset of the second pouch. Additionally, the

2. jaws are also configured to seal the adjacent side edges of both adjacent interconnected pouches. During a single sealing step, the sealing station is thus configured to provide a single triple point gusset seal in each of the two adjacent interconnected pouches.

Inthe 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°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.

The above impulse sealing device has the drawback that the temperature distribution over the resistor band cannot be controlled accurately during the relatively short pulse time. As a result, the sealing properties may not be accurate over the entire contour of the area that is to be sealed. In particular for sealing gusset portions of standing pouches, such quality is essential for achieving sufficiently low production failure rates.

The present invention aims to provide measures that provide an improved production of collapsible standing pouches.

The present invention aims to provide measures that enhance the quality of the seal that is obtained the film material of the pouch wall at the gusset and in particular at the triple points of the pouch.

The invention provides a production machine for the production of collapsible standing pouches, said pouches each having walls made from heat-sealable film material, preferably

-3- metal-free heat-sealable film material, wherein the production machine comprises a sealing station that is configured to heat seal bottom gussets of two adjacent pouches in a string of interconnected pouches made from heat-sealable film material, wherein the 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 front surface configured to contact the bottom gusset regions of a respective first wall of the two adjacent pouches, wherein the second jaw has a second front surface configured to contact the bottom gusset regions of a respective second wall of the two adjacent pouches, wherein each of the first and second jaws comprises at the respective front surface thereof at least one impulse heatable member that extends along the front surface and that is covered by a heat-resistant non-stick covering,

wherein the production machine is configured such that, in operation, string of interconnected pouches is positioned between the first and second jaws and that the impulse heatable elements of the first and second jaws each project at least partially over bottom gusset regions of two adjacent pouches,

and wherein the 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 - at the bottom gusset regions - the first and second walls and the gusset portions lying in between are clamped against one another by the front faces of the first and second jaws, and wherein the 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 heatable members, which impulses of heat seal to each other at least parts of the bottom gusset regions of the first and second walls of the two adjacent interconnected pouches, wherein the first and second jaws, at least the heatable elements 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 heatable elements have cooled down,

-4- 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 front surface, wherein each of the susceptor elements has a front surface that is at least shaped as an inverted T, such that the heat impulse is configured to seal at least a portion of side edge regions of the two adjacent interconnected pouches and to seal at least a portion of bottom edge regions of the two adjacent interconnected pouches, 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 front surface at the rear side of the respective at least one susceptor element, and wherein the 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 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 bottom gusset regions.

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 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.

Compared to the resistive heating in the known impulse heating devices, the impulse heating by means of an inductor element and susceptor element allows for more accurate controlling

-5.

of the heating. The latter contributes to a reliable and effective heat sealing between the walls of film material. 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 the inward located gusset portions. 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.

It has been found by the applicant that the impulse heating with the inductor and susceptor elements are in particular favourable for sealing the bottom gusset of pouches. The accurate controlling of the heating provides that, in the part of the pouch at and below the triple point, sufficient heat is provided to seal each two walls of the bottom lobes and that the amount of heat is not too large, in order to prevent that the opposed inner walls of the bottom lobes are welded against each other.

The inverted T-shaped susceptor elements each comprise three elongated susceptor parts, which are interconnected at a central portion of the susceptor element. In operation, a first one of the elongate susceptor parts projects towards a top end of the pouches and projects over the side edges of the two adjacent interconnected pouches. In operation, this upward elongate susceptor part thereby at least partially seals the side edges of the adjacent interconnected pouches.

Each of the other elongate susceptor parts at least has a component that projects away sideways from the upward elongate susceptor part, e.g. in a sideways, downward direction, over a bottom gusset of a respective pouch. In operation, each of these sideways elongate susceptor parts thereby at least seals a portion of the respective bottom gussets of the adjacent interconnected pouches.

In addition to the three elongate susceptor parts, the susceptor elements may comprise intermediate susceptor parts in between the elongate susceptor parts. With the intermediate susceptor parts, the sealing area of the susceptor element may be increased in order to provide for more rigid sealing of the bottom gussets of the pouches.

In an embodiment, the elongated inductor section is made from a metal, e.g. of copper.

-B- 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 embodiments, the at least one elongated inductor section has a constant cross-section, preferably a solid cross-section, over its length along the 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. In embodiments, the uniform cross-section elongated inductor section has, seen in a top view onto the jaw, a shape corresponding to the 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. In embodiments, the inductor of a jaw comprises multiple elongated inductor parts, e.g. three elongated inductor parts that are serially connected at a central portion of the inductor. A first one of the elongated inductor parts thereby projects over the upward elongate susceptor part. A respective second and third elongated inductor part thereby project over the respective sideways elongate susceptor parts. As such, the shape of the inductor substantially corresponds to the shape of the susceptor element, in order to provide an even distribution of eddy currents in the susceptor element.

In embodiments, the inductor of a jaw comprises multiple elongated inductor sections that are parallel to one another. In embodiments, the inductor of a jaw comprises multiple elongated inductor sections that extend along each other and that are spaced from one another by a slit, e.g. an air slitor a slit filled with electrically insulating material. In embodiments, the inductor comprises three elongated inductor sections. A first elongated inductor section spans over a first, e.g. sideways, downward elongated inductor part and the upward elongated inductor part. A second elongated inductor section spans over the upward elongated inductor part and a second, e.g. sideways, downward elongated inductor part. A third elongated inductor section spans over the second, e.g. sideways, downward elongated

-7- inductor part and the first, e.g. sideways, downward elongated inductor part. The elongated inductor sections extend parallel to one another and spaced from one another by a slit, thereby following the inverted T-shape of the susceptor element and thereby being arranged in proximity of the rear side of the susceptor element.

In embodiments, said slit between neighbouring inductor sections that are arranged above one another spans between 0.01 and 5 mm, more preferably between 0.1 and 2 mm. The presence of the slit between the 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 the slit between parallel inductor sections.

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.

In an embodiment, the susceptor element is embodied as an inverted T-shaped strip that extends over the slit between parallel elongated inductor sections and overlaps in said view with each of the parallel inductor section.

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.

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.

In an embodiment, the inductor of a jaw has the shape of an inverted T and comprises the first, second and third inductor sections being 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.

In an embodiment, the first and/or second jaw is provided with one inverted-T-shaped inductor element, having parallel first, second and third inductor sections interconnected in

-8- series, wherein the free ends of the inductor sections have terminals for electrical connection to the current source.

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 conductor 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.

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.

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.

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 element 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.

In an embodiment, at least one cooling fluid duct extends along the at least one conductor section that extends along the rear side of the susceptor element.

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.

-9- The cooling of the jaws may, as preferred, be configured to cause cooling of the heat-sealed bottom gusset before the jaws are opened, e.g. the film material being cooled to below 60°C before opening, e.g. to below 40°C.

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. For example, the susceptor element is made of, or comprises, aluminium, nickel, silver, stainless steel, and/or nickel-chrome. In an embodiment, the susceptor element is embodied as an inverted T-shaped plate having opposed front and rear main faces that define the thickness of the plate between them. In an embodiment, the thickness of the susceptor element plate is constant over the extension of the plate. 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. In an embodiment, each of the elongated susceptor parts is shaped as a strip, e.g. of a metal, e.g. of aluminium. Each of the strips may have a width in between 3 and 10 millimetres, e.g. between 4 and 8 millimetres. For example, as preferred, the strip has a constant height over its length. In an embodiment, the jaw is provided with a single continuous susceptor element embodied as an inverted T-shaped plate, e.g. of metal.

In an embodiment, the susceptor element, e.g. embodied as a plate, 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. 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

-10- 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.

Furthermore, the minimum thickness of the susceptor element is favourable for sealing the pouch at its triple point.

At the triple point, a discrete transition may be present in the thickness of the pouch, since the two side walls are sealed with the four walls of the bottom lobes.

Having a thin susceptor element provides the advantage that the susceptor element may deform when the first jaw and the second jaw are in their clamped position.

Upon deforming, the contour of the susceptor element is accommodated towards the thickness transition of the pouch walls, in order to provide for evenly-distributed heat transfer from the susceptor element towards the pouch at the triple point.

In an embodiment, the jaw is provided with a single continuous susceptor element embodied as an inverted T-shaped plate with three elongated susceptor parts that are shaped as strips, e.g. of metal, having a height of the strip between 3 and 10 millimetres, e.g. between 4 and 8 millimetres, and a thickness of between 0.08 and 0.8 mm, e.g. of between 0.3 and 0.5 mm.

For example, the strip is made of aluminium material.

In embodiments, the frequency of the electric current supplied to the inductor is between 250 KHz and 750 KHz.

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.

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

-11- 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.

Preferably, the entire spacing between the rear of the susceptor element and the neighbouring inductor section(s) is filled with electrically insulating material. 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. 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. In embodiments, in particular in embodiments of which a thickness of the susceptor element is small in comparison to the thickness of the inductor, the spacing in between the rear of the susceptor element and the neighbouring inductor section(s) is filled with a resilient material, for example with an elastically deformable material, such as silicone rubber. The resilient material may be able to deform in accordance with the thin susceptor element, in particular when the thin susceptor element is clamped against the triple point of the pouch, where the discrete transition is present in the thickness of the pouch. The inductor is relatively thick and may not deform due to the clamping. The resilient material may compensate for this difference in deformability between the inductor and the susceptor element, and may provide that a contact pressure is constant over the entire front surface of the susceptor element and that the susceptor element evenly abuts the pouch walls.

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 comprises glass or the like. In an embodiment the front face of the susceptor element is covered by a layer of Kapton tape, e.g. having a thickness of between 0.01 and 0.05 mm, e.g. of about 0.025 mm.

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

-12-

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.

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 Kaptan 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.

In an embodiment, the front surface of the jaw is smooth in a region of contact with the walls 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 the smooth design of the film material, in order to provide for a smooth region of contact.

In an embodiment, the jaws are configured, e.g. have appropriate dimensions, so that respective portion, e.g. at least halves of the bottom gussets of each of the two adjacent interconnected pouches are sealed in one cycle by the operation of the jaws. This avoids the needs for additional sealing actions at these portions of the bottom gussets.

In embodiment the sealing device is configured to provide a heat impulse with the susceptor element of between 150 and 300 degrees Celsius measured on the susceptor.

In an embodiment the heat impulse duration lies between 10 and 1000 milliseconds, e.g.

between 20 and 500 milliseconds.

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

-13- 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.

Ina 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.

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. In an embodiment, the film material comprises one or more layers each comprising or consisting of polyethylene (PE), 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. In an embodiment, the film material is made entirely from polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET). According to this embodiment, the film material consists of a single type of polymer, 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. In an embodiment the machine comprises one or more of: - aroll handling station adapted to receive one or more rolls of heat-sealable film material, - 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. a string of interconnected pouches, each pouch having at least one bottom gusset at its lower parts, being formed by two folded bottom lobes below a triple point 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,

-14- - 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, - for example a sealing station as discussed herein, - a feed mechanism adapted and operated to feed said formed pouches, e.g. as a string of interconnected pouches, to the sealing device, which devices may be located at one at the same station.

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.

In embodiments, the machine comprises a filling station, configured to fill a product into the pouch.

In an embodiment the filling station is configured to fill the product into the pouch prior to the sealing of a spout to the pouch. The filling can then, for example, be performed via a non- bonded edge region at the top of the pouch into which the spout is sealed at a later stage.

In an embodiment, the filling of the pouch on the production machine is done after performing the impulse sealing cycle at the mentioned station, e.g. after sealing the bottom gusset of the pouch and after sealing a spout in between the pouch walls. For example, the filling is done via the spout, e.g. in an aseptic filling device, optionally followed by a closing step wherein the spout is closed, e.g. in a capping station provided with a capping device configured and operated to place a cap on the spout.

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 sealing station, preferably also any further sealing station, such as a spout sealing station, so that the formation of a hermetically closed pouch is performed in said sterile or aseptic chamber. In an embodiment a filling station is arranged in 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.

-15- 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.

In an embodiment all sealing devices of the production machine, including the 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. The present invention also relates to a method for the production of collapsible standing pouches, comprising one or more gussets, such as a bottom gusset, wherein use is made of a production machine as described herein. Embodiments of the pouch production system and method will be described by way of example only, with reference to the accompanying drawings in which reference symbols indicate corresponding parts, and in which: Fig. 1 schematically shows an embodiment of the production machine according the invention, Fig. 2 illustrates schematically the sealing stations in the machine of figure 1, Fig. 3 illustrates a standing pouch produced with the machine of figure 1, Fig. 4 illustrates a triple point in the pouch of figure 3, Figure 5 schematically depicts an inverted T-shaped susceptor element and corresponding inductor, Fig. 6 illustrates a cross-section through an elongated part of an inverted T-shaped inductor, Fig. 7 illustrates a cross-section through an elongated part of an inverted T-shaped inductor, wherein a resilient layer is provided between the susceptor and the inductor, Fig. 8 illustrates the electromagnetic field generated by an elongated part of the inverted T- shaped inductor and the susceptor element in said field, Figs. 9, 10, 11, 12 depict various embodiments of an inductor, and Fig. 13 depicts an embodiment of a first jaw of the gusset sealing device of figure 2.

-18- Figure 1 schematically depicts an embodiment of the production machine for the production of collapsible standing pouches, to which is referred with reference numeral 1. The machine is also known a Form-Fill-Seal (FFS) machine, in particular in the depicted embodiment a horizontal FFS machine.

The pouch production machine 1 is configured to produce collapsible pouches 2, here standing collapsible pouches, that are filled with a product. In the depicted example the top edge is sealed over its length. In an alternative embodiment a plastic spout or other fitment is sealed into the top edge.

The pouches 2 each having walls 3, 4 made from metal-free heat-sealable film material 5. The pouch production machine 1 has a frame (not shown) provided with a film supply device 6 that is adapted to receive one or more rolls 7 of flexible heat-sealable film material 5. In the machine 1, the film material is unwound from the roll 7. After unwinding, the film material 5 is led towards a bottom gusset folding device 8 to fold the film material dispensed from a single roll into a folded shape, so that two pouch walls 3,4 oppose one another and so that the bottom has a gusset as is well known in the art.

Up till the moment of separation of a complete pouch 2, there is a string of interconnected pouches that are being formed in the machine, here also filled and then sealed hermetically. In figure 1, the individual pouches 2 in the string are displayed separated by means of the dashed lines in between them. Each pouch 2 has a bottom gusset 9 with first and second gusset portions at its lower end, being formed by two folded bottom lobes.

In between the first pouch wall 3 and the second pouch wall 4, the first and second gusset portions lobes are interconnected along a fold line 10. At their respective side edges or seams, the pouches 2 have a triple point 11 at the height of the fold line 10.

The machine 1 further comprises a cutting station 12, which is configured to make one or more cuts to shape and/or separate, e.g. in part, the pouches 2.

-17- A feed mechanism is provided, here being formed by a set of traction rolls 13, which is adapted and operated to unwind the roll 7 and to feed said string of interconnected pouches 2 along the sealing devices at stations 15,16.

Furthermore, a filling station 14 is provided, which is configured to fill a product into the pouch 2. The production machine 1 comprises a sealing station that is configured to heat seal the pouches. The sealing station comprises a gusset sealing device 15 for sealing bottom gussets 9 of two adjacent pouches 2 in a string of interconnected pouches 2. The bottom sealing device 15 is configured to heat seal the pouch in the region of the gusset, e.g. to make a heat seal between the first pouch wall and the first gusset portion that is directly inward thereof and a heat seal between the second pouch wall and the second gusset portion that is directly inward thereof.

Downstream of the gusset sealing device 15, along transportation direction (T), the sealing station comprises a side edge or side seam sealing device 16 for sealing side edges of two adjacent pouches 2 in a string of interconnected pouches 2.

Further downstream, the sealing station comprises a top edge sealing device 17 for sealing top edges of the pouches 2, here after filling the pouches at filling station 14 via the still open top edge.

Infigure 1, a single jaw 18 of the gusset sealing device 15 is displayed. This first jaw 18 faces towards the bottom gusset 9 on the first side wall 3. On the opposite side of the string of interconnected pouches 2, the gusset sealing device 15 comprises a second jaw, which faces the towards the bottom gusset 9 on the second side wall 4.

The gusset sealing device 15 is provided with an actuator device 15a, configured to move the first jaw 18 and second jaws relative to one another between an opened position and a clamped position.

The gusset sealing device 15 further comprises a cooling device 20 configured to cool each of the first jaw 18 and second jaw.

In figure 2, the sealing actions of the machine 1 are shown schematically.

-18- The first jaw 18 of the bottom sealing device 15 comprises a susceptor element 19, which has a front surface that is at least shaped as an inverted T. In figure 2, an exemplary contour of the susceptor element 19 is displayed. The front surface of the susceptor element is positioned against the first pouch wall 3 in the clamped position. On the opposite side of the string of interconnected pouches 2, a similar susceptor element of the second jaw is positioned against the second pouch wall 4.

During operation of the machine 1, as in the configuration in figure 2, the susceptor element 19 projects partially over bottom gusset portions 9 of two adjacent interconnected pouches 2. A vertical centreline of the susceptor element 19 is thereby aligned with a separation line between side edges of two adjacent pouches 2. The susceptor element 19 thereby projects halfway over a first pouch 2 with a first elongate susceptor part 20 and projects halfway over a second pouch 2” with a second elongate susceptor part 21. The susceptor element 19 further comprises an upward elongated susceptor part 22, which projects towards a top end of the pouches 2 and projects over the side edges of the two adjacent interconnected pouches 2’, 2”. In operation, this upward elongate susceptor part 22 thereby at least partially seals the side edges of the adjacent interconnected pouches. The first elongate susceptor part 20 and the second elongate susceptor part 21, together with the upward susceptor part 22, form a susceptor element 19 that has the shape of an inverted T. In between the three elongate susceptor parts 20, 21, 22, the susceptor element 19 comprises two intermediate susceptor parts, in order to form a smooth transition in geometry between the elongate susceptor parts 20, 21, 22. By having an inverted T-shaped susceptor element 19, gusset sealing device 15 simultaneously seals a part of a bottom gusset 9 of the first pouch 2’ and seals a part of bottom gusset 9 of the second pouch 2”. The susceptor element 19 further projects over the triple points 11 of the adjacent pouches 2, which are located at the height of the folding line 10.

Atthis triple point 11, a heat seal is made by first jaw 15 between the first pouch wall 3 and the first gusset portion 3a that is directly inward thereof and a heat seal is made by the second jaw between the second pouch wall 4 and the second gusset portion 4a that is

-19- directly inward thereof. So at point 11, a discrete transition in thickness of the pouch 2 occurs between the upper -two- layers and the lower -four- layers of film material 5.

The gusset sealing device 15 further comprises an inductor 24 in the first jaw 18, not shown in figures 1 and 2. The inductor 24 is electrically insulated from the susceptor element 19 and comprises an elongated inductor section that extends along the respective front surface and at the rear side of the susceptor element 19.

In operation, an electric current source is operated to temporarily feed a high frequency alternating electric current to the inductor 24, thereby generating a high frequency electromagnetic field with the inductor 24, wherein the high frequency electromagnetic field induces alternating eddy currents in the susceptor element 19.

The eddy currents generate an impulse of heat that is emitted by the susceptor element 19, which impulse of heat seal the bottom region of pouch wall 3 to the adjoining gusset portion 3a. The same holds true for the other jaw.

In figures 3A and 3B, a cross-section of the first jaw 18 is displayed, being disposed in the clamped positon against the first pouch wall 3. The first jaw 18 comprises a main body 25 that is provided with one or more cooling fluid ducts. The cooling fluid is a cooling liquid, such as water, being passed through the cooling fluid ducts, for example by means using a pump assembly. A cooling liquid circuit is provided, which is a closed circuit including a heat exchanger configured to remove heat from the cooling liquid.

The thickness of the susceptor element 19 is small in comparison to the thickness of the inductor 24. A spacing is present between the susceptor element 19 and the inductor 24, which is filled with an electric insulator 26, in order to prevent short-circuiting between both during operation of the gusset sealing device 15. The insulator 26 is made from a resilient material, for example from an elastically deformable material, such as silicone rubber. The resilient material enables deformation of the insulator 26, in accordance with deformation of the thin susceptor element 19.

This deformation is in particular advantageous when the thin susceptor element 19 is clamped against the triple point 11 of the pouch 2, as displayed in figure 3B. where the discrete transition is present in the thickness of the pouch 2. The inductor 24 is relatively thick and will not deform in the clamped position, whereas the thin susceptor element 19 will deform against the first pouch wall 3 at the triple point 11. The resilient material of the

-20- insulator 26 will compensate for this difference in deformability between the inductor 24 and the susceptor element 19, and provides that a contact pressure is constant over the entire front surface of the susceptor element 19 and that the susceptor element 19 evenly abuts the first pouch wall 3.

In figure 5, an embodiment of the susceptor element 19 and the inductor 24 is displayed. The susceptor element 19 is shown spaced from the inductor 24, in order to show the shape of the inductor 24.

During operation of the gusset sealing device 15, a front surface 27 of the susceptor element 19 is very close to a wall of the pouch. The inductor 24 faces an opposing rear side of the susceptor element 19.

The front surface of the susceptor element 19 has the shape of an inverted T, i.e. an upside- downT.

The susceptor element 19 comprises three elongate susceptor parts 20, 21, 22, which are interconnected at a central portion 28 of the susceptor element 19.

In operation, the upward elongate susceptor part 22 projects towards a top end of the pouch. The first elongate susceptor part 20 and the second elongate susceptor part 21 are aligned in opposite directions with a component that projects away sideways from the upward elongate susceptor part 22, e.g. being aligned in sideways, downward directions.

The susceptor element 19 is embodied as a continuous inverted T-shape with three elongated susceptor parts 20, 21, 22 that are each shaped as an elongated strip.

The inductor 24 comprises multiple elongated inductor parts, e.g. three elongated inductor parts that are serially connected at a central portion of the inductor 24. A first elongated inductor part 29 thereby projects over the first elongate susceptor part 20. A second elongated inductor part 30 thereby projects over the second elongate susceptor part 21. Furthermore, a third elongated inductor part 31 projects over the upward elongate susceptor part 22. As such, the shape of the inductor 24 substantially corresponds to the shape of the susceptor element 19, in order to provide an even distribution of eddy currents in the susceptor element 19 during operation of the gusset sealing device 15.

-21- The inductor 24 comprises three groups, here pairs, of adjacent elongated inductor sections 32a,b, 33a,b, 34a,b. A first group, here pair, of elongated inductor sections 32a,b forms the upward elongated inductor part 31. A second group, here pair, of elongated inductor sections 33a, b the second elongated inductor part 30.

The elongated inductor sections 32a,b, 33a,b, 34a,b extend pairwise parallel to one another and spaced from one another by a slit 35, thereby following the inverted T-shape of the susceptor element 19.

They are arranged in proximity of the rear side of the susceptor element 19.

The slit 35 in the inverted T-shaped inductor 24 projects onto the inverted T-shaped susceptor element 19, in order to provide a homogeneous high frequency electromagnetic field of the field, thereby contributing to the homogeneity of the impulse heating of the susceptor element 19.

The elongated inductor sections 33a,b are connected via a bend 36. The elongated inductor sections 324,b via a bend 37. The inductor sections 34a,b have terminals for electrical connection to the current source. The bend 36, the bend 37 and the free ends 38 project outside the contour of the susceptor element 19.

It is shown in figures 5 and 8, that a jaw is embodied such that the high frequency electromagnetic field generated by the inductor part 33 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.

29. Figure 9 depicts an alternative embodiment of the inductor 24, being embedded in the main body 25 of the first jaw 18. This inductor 24 is relatively wide, compared to its height. The first elongate inductor part 29 and the second elongate inductor part 30 of the inverted T-shaped inductor 24 have a length that is substantially larger than the length of the upward elongate inductor part 31. As such, this inductor 24 is in particular suited to weld pouches with a relatively low bottom gusset, of which the triple point is located at a relatively low portion of the pouch. In figure 10, a further alternative embodiment of the inductor 24 is displayed, being embedded in the main body 25 of the first jaw 18 as well. This inductor 24 comprises a plurality of parallel inductor sections, each being separated from an adjacent one by a slit. On top of the inductor 24, a susceptor element 19 is arranged. The susceptor element 19 has a front surface 27 with the shape of an inverted T, comprising three elongate susceptor parts 20, 21, 22, of which a first elongate susceptor part 20 and a second elongate susceptor part 21 extend substantially sideways in opposite directions. An upward elongate susceptor part 22, extends upwards, projecting towards a top end of the pouches that are to be sealed. In between the first elongate susceptor part 20 and the upward elongate susceptor part 22, the susceptor element 19 comprises a first intermediate susceptor part 20’, in order to form a smooth transition in geometry between the first elongate susceptor part 20 and the upward elongate susceptor part 22. In between the second elongate susceptor part 21 and the upward elongate susceptor part 22, the susceptor element 18 comprises a second intermediate susceptor part 21’, in order to form a smooth transition in geometry between the second elongate susceptor part 21 and the upward elongate susceptor part 22.

Figure 11 depicts a further alternative embodiment of the inductor 24. This inductor 24 is relatively wide, compared to its height. The first elongate inductor part 29 and the second elongate inductor part 30 of the inverted T-shaped inductor 24 have a relative smooth transition into the upward inductor part 31 of the inductor 24. At the upward inductor part 31, arelatively sharp first bend 36 is provided between the first elongated inductor section 32 and the second elongated inductor section 33, in order to optimize the geometry of the inductor 24 for achieving a substantially homogeneous high-frequency electromagnetic field during use.

In figure 12 another embodiment of the inductor 24 is displayed. This inductor 24 is relatively narrow, compared to its height. The first elongate inductor part 29 and the second elongate inductor part 30 of the inverted T-shaped inductor 24 have a length that is substantially

23. smaller than the length of the upward elongate inductor part 31. As such, this inductor 24 is in particular suited to weld pouches that are relatively narrow, compared to their height.

Furthermore, this embodiment of the inductor 24 allows simultaneous sealing of bottom gussets of two adjacent interconnector pouches, with the first elongate inductor part 29 and the second elongate inductor part 30 that extend in opposite sideways directions, and sealing of complete side edges of the two adjacent interconnector pouches over their entire height from their bottom ends to their top ends.

In figure 13, an embodiment of the first jaw 18 is displayed in more detail.

The first jaw 18 has the inductor 24 embedded in its main body 25. The jaw 18 is provided with a cooling fluid duct in the main body 25. Within the main body 25, the cooling liquid is passed in close proximity to the inductor 24, e.g. directly behind it.

The jaw 18 further comprises a cooling fluid entrance port 39 and a cooling fluid exit port 40 protruding from the main body 25, configured to be connected to a cooling liquid circuit with a pump assembly and a heat exchanger configured to remove heat from the cooling liquid exiting the jaw 18.

Claims

- 24. CONCLUSIONS

1. Production machine for the production of foldable upright pouches, wherein the pouches each have walls made of heat-sealable film material, preferably metal-free heat-sealable film material, wherein the production machine has a sealing station that is arranged to mold two adjacent pouches into the bottom. a ribbon of interconnected pouches made of heat-sealable film material for heat sealing, the sealing station comprising: - an impulse sealing device, comprising a first jaw and a second jaw, - an actuator device, adapted to move the first and second jaws relative to move each other between an open position and a clamped position, a cooling device adapted to cool each of the first and second jaws, the first jaw having a first front surface arranged to close the bottom gelling regions of a first wall of the two adjacent pouches , the second jaw having a second front surface arranged about the bottom contact areas of a second wall of the two adjacent pouches, each of the first and second jaws having on their respective front surface at least one impulse heatable element extending along the front surface and covered with a heat resistant non-stick layer, wherein the production machine is arranged such that, in use, the ribbon of interconnected pouches is positioned between the first and second jaws and that the heatable element each protrudes at least partially over bottom sealing regions of two adjacent interconnected pouches, and wherein the sealing station is adapted to perform an impulse sealing cycle, the actuator device being arranged to bring the first and second jaws into the clamped position so that - in the bottom gusset regions - the first and second walls and the gusset portions are clamped together by the front surfaces of the gusset. first and second jaws, and wherein the sealing station is ing in the clamped position, temporarily activate the pulse-heatable element to generate a heat pulse which is emitted from each of the heatable elements, whereby the

- 25.

first and second jaws, at least their heatable elements, cool after completion of the actuation and are thereby assisted by the operation of the cooling device, and wherein the actuator device is arranged to move the first and second jaws to the open position after the heatable elements are cooled, each pulse-heatable element being a susceptor element comprising electrically conductive material, the susceptor element having a back side remote from the respective front surface, each of the susceptor elements having a front surface shaped at least as an inverted T, so that the heat pulse is arranged to seal at least a portion of side edge regions of the two adjacent interconnected pouches and to seal at least a portion of bottom edge regions of the two adjacent interconnected pouches, and wherein each of the first and second jaws has an inductor includes those elect is isolated from the respective susceptor element, the inductor having an elongated inductor portion extending, along the respective front surface, to the rear of the respective at least one susceptor element, and the sealing station comprising a high frequency electrical power source connected to the inductor of each of the first and second jaws, the sealing station being arranged such that, during the impulse sealing cycle, the electrical power source is controlled to temporarily supply a high-frequency electrical current to the inductors, thereby generating a high-frequency electromagnetic field with the inductors wherein the high-frequency electromagnetic field creates eddy currents in the respective susceptor element, which generate a heat pulse emitted from the susceptor element, the pulses heat sealing the ground vein.

The production machine of claim 1, wherein each of the susceptor elements comprises three elongated susceptor portions and intermediate susceptor portions in between the elongated portions.

- 26 -

A production machine according to claim 1 or 2, wherein the inductor of a jaw comprises a plurality of elongated inductor parts, for example three elongated inductor parts interconnected in a central portion of the inductor.

A production machine according to any one of the preceding claims, wherein the inductor of a jaw, e.g. each elongated inductor portion thereof, comprises a plurality, e.g. a pair of, elongated inductor portions extending past each other and spaced apart by a gap, for example an air gap or a gap filled with an electrically insulating material.

Production machine according to claim 3 or 4, wherein the inductor comprises three elongated inductor parts.

Production machine according to claim 4 or 5, wherein the inductor of a jaw is in the form of an inverted T and comprises the first, second and third inductor parts, each comprising a plurality of elongated inductor parts interconnected in series, for example by a bent portion. at the outer ends of the legs of the T.

Production machine according to any one of the preceding claims, wherein the machine is arranged such that the cooling of the jaw is active during the entire impulse sealing cycle.

Production machine according to any of the preceding claims, wherein the susceptor element is made of a metal material, for example a metal or a metal alloy, for example a thin metal strip, for example comprising aluminum, nickel, silver, stainless steel, and / or nickel-chromium.

A production machine according to any preceding claim, wherein each jaw includes a single continuous susceptor element configured as a body shaped like an inverted T with three elongated susceptor members shaped as strips.

Production machine according to any one of the preceding claims, wherein a thickness of the susceptor element is small relative to a thickness of the inductor, a distance between the rear of the susceptor element and the adjacent inductor portion (s) being filled with a resilient material, for example with an elastically deformable material, such as silicone rubber.

-27-

A production machine according to any one of the preceding claims, further comprising one or more of: - a roll handling station, adapted to receive one or more rolls of heat sealable film material, - one or more pouch forming stations, adapted and operative to forming the roll handling station into a succession of pouches, e.g. a ribbon of interconnected pouches, each pouch having at least one bottom gusset in its lower portion, which is formed by two folded bottom flaps below a triple point of the pouch, e.g. a pouch forming station that is configured as a folding station, for example to fold film material dispensed from a single roll into a shape with a bottom edge, for example a pouch forming station configured as a cutting station, for example to make one or more cuts around the pouches, for example partially to form and / or to separate, - a feeding mechanism, adapted and operative to feed the formed pouches, for example as a ribbon of interconnected pouches, to the sealing device, wherein these devices can be located at one and the same station.

12. Production machine according to claim 11, further comprising a filling station, arranged to fill a product in the pouch.

Production machine according to claim 11 or 12, further comprising a sterilization station for the film material, which is arranged to subject the film material delivered by the one or more rollers to a sterilization process.

The production machine of claim 13, further comprising a sterile or aseptic chamber extending from the film material sterilization station to the sealing station, preferably also to a further sealing station, such as a spout-sealing station, such that the formation of a hermetically sealed pouch is performed in the sterile or aseptic chamber.

A method for the production of foldable upright pouches, comprising one or more gussets, such as a bottom gouge, wherein use is made of a production machine according to any one of the preceding claims.