NL2023584B1

NL2023584B1 - Impulse heat sealing of a heat-sealable film material

Info

Publication number: NL2023584B1
Application number: NL2023584A
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

A sealing station configured to heat seal a wall made from heat-sealable film material, preferably metal-free heat-sealable film material, onto one another wall of heat-sealable material, e.g. another wall of heat-sealable film material, to create a sealed seam. The sealing station comprises an impulse sealing device comprising a firstjaw and a second jaw, wherein at least the first jaw comprises at the respective front surface thereof at least one, e.g. a single elongated, impulse heatable member that extends along the respective front surface and that is covered by a heat-resistant non-stick covering.

Description

P34194NL00O IMPULSE HEAT SEALING OF A HEAT-SEALABLE FILM MATERIAL The present invention relates to the impulse sealing of two walls made from heat-sealable material, wherein one of said walls is made of heat-sealable film material, preferably metal- free heat-sealable film material. For example, the impulse sealing is used to provide an elongated sealed seam of a collapsible pouch. For example, the elongated seam is a bottom seam, a vertical or side seam, or a top seam of a pouch.

In the field of pouch production it is 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, with the 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 seam regions of the two walls onto each other. The resistor band 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 elevated temperature extremely fast to 200°C or much higher temperatures like 300°C, 400°C or even 500°C, 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 present invention aims to provide measures that provide an improved impulse sealing. The present invention aims to provide measures that enhance the quality of the seal that is obtained between the seam regions of the walls of heat-sealable material.

The invention provides a sealing station configured to heat seal a wall made from heat- sealable film material, preferably metal-free heat-sealable film material, onto one another

2. wall of heat-sealable material, e.g. another wall of heat-sealable film material, to create a sealed seam, wherein the sealing station comprises: -animpulse 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 at least one of the first and second jaws,

wherein the first jaw has a first front surface configured to contact an elongated seam region of a respective first wall made from heat-sealable film material, wherein the second jaw has a second front surface configured to contact an elongated seam region of a respective second wall made from heat-sealable film material,

wherein at least the first jaw comprises at the respective front surface thereof at least one, e.g. a single elongated, impulse heatable member that extends along the respective front surface and that is covered by a heat-resistant non-stick covering,

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 the seam regions of the first and second walls are clamped against one another by the first and second jaws, and wherein the sealing station is configured to, in the clamped position, temporarily energize each impulse heatable member so as to generate an impulse of heat that is emitted by each heatable member, which impulse of heat seals the seam regions of the first and second walls to each other, wherein at least one of the first and second jaws is cooled by the cooling device after termination of the energizing of the heatable member, and wherein the actuator device is configured to move the first and second jaws into the opened position after the heatable element has 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 front surface,

and wherein at least one of the first and second jaws comprises an inductor that extends along the respective front surface,

-3- and wherein the sealing station comprises a high frequency electric current source, which is connected to the inductor, 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 inductor, thereby generating a high frequency electromagnetic field with the inductor, wherein the high frequency electromagnetic field induces eddy currents in the susceptor element generating an impulse of heat that is emitted by the susceptor element, which impulse of heat seals the seam regions of the walls to each other.

In an embodiment both of walls to be joined are made from heat-sealable film material, preferably metal-free heat-sealable film material, e.g. in the production of collapsible pouches.

In another embodiment one wall is made of heat-sealable film material, whereas the other wall is different with respect to one or more of its flexibility, thickness, manufacturing method, etc. For example, the other wall is a wall of a formed product, e.g. a thermoformed product, for example a plastic tray for packaging of articles, e.g. a plastic food packaging tray, a formed blister packaging component, etc.

In an embodiment the first jaw is provided with the susceptor element and the second jaw is devoid of a susceptor element, wherein the second jaw is provided with the inductor and the first jaw is devoid of an inductor. In this arrangement the inductor in the second jaw generates a high frequency electromagnetic field that induces alternating eddy currents in the susceptor element of the first jaw, thereby generating an impulse of heat that is emitted by the susceptor element of the first jaw, which impulse of heat seal the seam regions of the walls to each other. An advantage of this design is that the susceptor element can be cooled effectively, e.g. by arranging at least one cooling fluid duct in proximity to the susceptor element, e.g. the cooling fluid duct extends along the rear side of the susceptor element, e.g.

parallel to the susceptor element. In this design the second jaw can also be cooled by the cooling device, e.g. by arranging at least one cooling fluid duct in proximity to the inductor, e.g. the cooling fluid duct extends along the elongated inductor section.

In another embodiment the first jaw also comprises an inductor that extends along the respective front surface, that is electrically insulated from the susceptor element, and that comprises an elongated inductor section at the rear side of the respective at least one susceptor element of the first jaw. In an embodiment the second jaw may be just a counter

-4- member, so devoid of any heating facility. In an embodiment the second jaw may cooled by the cooling device, e.g. the second jaw having at least one cooling fluid duct. In an embodiment, the first jaw can be cooled by the cooling device, e.g. by arranging at least one cooling fluid duct in proximity to the inductor, e.g. the cooling fluid duct extends along the elongated inductor section. Due to the extension of the at least one elongated inductor section along the front surface of the jaw, e.g. a rectilinear inductor section, and also along, generally parallel, to the susceptor element, e.g. in an embodiment at the rear side of the at least one susceptor element, preferably in close proximity to said rear side, 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 seam regions of 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 sealing jaws. The clamping force may effectively only serve to assure an intimate surface contact between the walls.

In an embodiment, the susceptor element is, seen in front view thereon, rectilinear so as to establish a rectilinear heat seal between the walls.

In another embodiment, the susceptor element is, seen in front view thereon, elongated having distinct ends, yet includes one or more curved sections between said distinct ends.

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

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

-5.

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.

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, in embodiments a rectilinear shape, 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 sections that are parallel to one another, e.g. rectilinear elongated inductor sections.

In embodiments, the inductor of a jaw comprises multiple elongated inductor sections that are parallel to one another, e.g. rectilinear elongated inductor sections, and vertically spaced from one another by a 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 spaced from one another by a slit. In an embodiment said single pair of elongated inductor sections is arranged in proximity of the rear side of the susceptor element of the first jaw.

In embodiments, said slit between neighbouring inductor sections, e.g. rectilinear elongated inductor sections, has a height or width between 0.01 and 5 mm, more preferably between

0.1 and 2 mm. when the inductor sections are parallel and horizontal, this size relates to the height of the slit, otherwise the width of the slit is envisaged.

In an embodiment, the inductor of the first jaw comprises a pair of parallel inductor sections arranged at the rear side of the susceptor element, e.g. rectilinear elongated inductor sections, e.g. 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 sections in the first jaw.

-B- The presence of the slit between the parallel elongated inductor sections, e.g. rectilinear 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 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 one strip that extends over the slit between parallel elongated inductor sections, e.g. rectilinear elongated inductor sections, and overlaps in said view with each of the parallel inductor section.

In an embodiment, a strip shaped susceptor element has opposed edges, e.g. an upper edge and a lower edge, defining a height or width of the strip, wherein the height or width of the strip is at least 50% of the height or width of the single pair of inductor sections including the slit that are arranged at the rear of the strip, e.g. between 75% and 125% of said height or width, e.g. about 100% of said height or width.

In an embodiment, a strip shaped susceptor element has opposed edges, e.g. 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, e.g. two or more than two, inductor sections, e.g. rectilinear elongated inductor sections. Herein the height or width of the strip is preferably at most the same as the height or width of the number of one or more inductor sections, preferably the edges of the strip not protruding outside the height or width of the assembly of the one or more inductor sections.

In an embodiment, the inductor of a jaw is embodied so that in a pair of adjacent and parallel inductor sections, e.g. that are arranged at the rear side of the susceptor element, e.g.

rectilinear elongated inductor sections, the current flows in the same direction through the inductor sections.

rectilinear elongated inductor sections, the current flows in opposite directions through the inductor sections.

-7- In an embodiment, the inductor of a jaw comprises a C-shaped inductor element having parallel first and second inductor sections, e.g. rectilinear elongated 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.

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.

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, e.g. rectilinear elongated inductor sections, wherein the free ends of the inductor sections have terminals for electrical connection to the current source.

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 adjacent, e.g. above one another, wherein the inductor sections are separated by a slit, e.g. an air slit or a slit filled with electrically insulation material.

In an embodiment, the inductor of a jaw comprises multiple, e.g. just two or four or six, elongated inductor sections arranged parallel to one another, e.g. rectilinear inductor sections, and arranged alongside, e.g. above, one another behind the susceptor element.

In an embodiment, the inductor of the first jaw comprises multiple inductor sections arranged parallel to one another and arranged above one another behind the susceptor element, e.g. rectilinear elongated inductor sections.

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.

In an embodiment the at least one elongated inductor section, e.g. rectilinear 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

-8- 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, e.g. rectilinear elongated inductor sections, has a rectangular cross-section with a height or width that is greater than the thickness of the inductor section. This arrangement allows to limit the thickness, which allows far efficient cooling. At least one, preferably 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 one or both of 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 a 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 and/or the susceptor element.

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.

Itis preferred for the sealing device to be configured such that cooling 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.

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

-9- The cooling of the jaws may, as preferred, be configured to cause cooling of the heat-sealed region before the jaws are opened, e.g. the film material being cooled to below the crystallization temperature of the polymer material involved in the join.

A benefit of the cooling is that, before the release from the jaws, the sealed 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, e.g. in view of transport of a pouch or string of interconnected pouches through a pouch production 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.

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 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.

In an embodiment, the susceptor element is embodied as a planar strip, most preferably the first jaw having a single planar strip susceptor element. This arrangement as a planar strip is in particular preferred. Herein, preferably, the plane of the susceptor element is parallel to the plane of seam regions to be joined.

The front of the jaw equipped with the susceptor element, possibly both jaws being equipped with a susceptor element and an associated inductor, is preferably smooth, so devoid of any relief that locally holds the wall of film material away from the jaw and creates air pockets between the jaw and the walls of film material. This smooth design 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 walls of film material clamped onto one another in the seam regions.

-10- 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, 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 40 millimetres, e.g. between 10 and 30 mm. For example, as preferred, the strip has a constant height over its length.

Preferably, the susceptor element strip lacks apertures over its extension. In an embodiment, the jaw is provided with a single continuous susceptor element embodied as a strip, e.g. of metal.

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 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, e.g. 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.

In an embodiment, the first jaw is provided with a single continuous susceptor element embodied as a strip, e.g. of metal, having a height or width of the strip between 3 and 40 mm, e.g. between 10 and 30 mm, e.g. of 25 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 or nickel material.

In embodiments, the frequency of the alternating electric current supplied to the inductor is between 250 KHz and 750 KHz. In an embodiment, the sealing device 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

-11- 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 particular for sealing a seam extending across a gusset portion, in particular across the so- called triple point associated with the presence of a gusset portion, e.g. in a gusset bottom type or gusset side collapsible pouch, 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 walls, e.g. of film material walls, in the area of the seam to be made. 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. See for instance WO2013/066328. For example, in an embodiment, a silicone rubber layer is provided behind the susceptor element. For example, the resilient layer has a thickness between 0.5 and 2.0 millimeter. 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.

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. In an embodiment, the elongated inductor section is arranged at the rear of the susceptor element in the first jaw, possibly the second jaw being of similar design, 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. The minimum values of this spacing are primarily envisaged to allow for effective electrical insulation between the inductor section(s) an 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

-12-

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 multiple 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 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 electrically insulating material, e.g. tape, e.g. 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

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 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 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 having the susceptor element, is smooth in a region of contact with the wall of film material, so lacking or devoid of any relief that would

-13- locally keep the film material away from the front surface, so lacking for example one or more ribs, bosses, etc. 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 generate 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.

The main body can be 3D-printed if desired. For example, the one or more cooling ducts are provided, e.g. machined, in the main body.

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 sections. 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 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. In embodiment, the sealing device is configured to provide a heat impulse with the susceptor element of between at least 150°C and at most any of 200°C, 300°C, 400°C, or 500°C measured on the susceptor.

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. 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.

-14- It is noted that control of the temperature that is reached during the impulse heating may be done on the basis of monitoring the supply of electrical power to the inductor.

In an embodiment wherein both the first jaw and the second jaw of a sealing device each comprises a susceptor element and an inductor, it is primarily envisaged that both jaws are operated simultaneously to provide a heat impulse to the region to be joined.

In an alternative operational method, it is envisaged that the jaws of a sealing device each comprises a susceptor element and an inductor, and that the jaws are operated in alternating manner, so the first jaw sealing a first seam region in a first cycle and the second jaw sealing a second seam in a second cycle. This approach may allow for a relatively long cooling period of the jaw before the inductor of the jaw is energized again.

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 ata 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.

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.

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 the susceptor element of the jaw, 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

-15- that is fed to the inductors 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.

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.

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.

The sealing device is primarily envisaged for sealing of metal-free film material. For example, the film material of the first wall, or of both 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.

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 wall only comprises a single polymer.

In an embodiment a conveyance mechanism is provided that is configured to convey the walls to be sealed, e.g. individual pouches or a string of interconnected pouches having heat- sealable film material walls, along a path of conveyance, wherein the sealing station as

-18- 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, in pouch production, a so-called walking beam conveyance mechanism is employed for stepwise conveyance.

The sealing action is then performed with the walls to be joined, e.g. the pouch, at rest, in practical embodiments with the sealing station mounted stationary in a machine, at least with regards to the direction of conveyance.

In an embodiment the conveyance mechanism is configured and operated to convey the walls to be joined, e.g. of individual pouches or of 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 is configured to move a pair of jaws in synchronicity with the continuously moving walls to be joined during the impulse sealing cycle.

An advantage of this approach that undesirable deformations of the walls, e.g. 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.

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.

The sealing device as discussed herein may form part of a production machine for the production of collapsible pouches, e.g. spouted collapsible pouches or collapsible pouches with another type of fitment or pouches lacking a fitment, said pouches each having walls made from heat-sealable film material, preferably metal-free heat-sealable film material.

The present invention also relates to a production machine for the production of collapsible pouches, said pouches each having walls made from heat-sealable film material, preferably metal-free heat-sealable film material, wherein the production machine comprises a sealing station that is configured to heat seal the walls onto one another to create a sealed seam of the pouch, wherein the sealing station comprises: - an impulse sealing device comprising a first jaw and a second jaw,

-17-

- 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 at least one of the first and second jaws,

wherein the first jaw has a first front surface configured to contact an elongated seam region of a respective first wall of the pouch, wherein the second jaw has a second front surface configured to contact an elongated seam region of a respective second wall of the pouch,

and wherein at least one of the first and second jaws comprises an inductor that extends along the respective front surface, wherein, preferably, the first jaw comprises an inductor that extends along the respective front surface, wherein the inductor is electrically insulated from the susceptor element, and wherein the inductor comprises an elongated inductor section at the rear side of the respective at least one susceptor element,

-18- and wherein the sealing station comprises a high frequency electric current source, which is connected to the inductor, 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 inductor, thereby generating a high frequency electromagnetic field with the inductor, wherein the high frequency electromagnetic field induces alternating eddy currents in the susceptor element generating an impulse of heat that is emitted by the susceptor element, which impulse of heat seal the seam regions of the walls to each other.

In an embodiment the production machine further comprises 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 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 interconnected pouches, 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, - afitment, e.g. spout, inserting device adapted to insert an attachment portion of a fitment in a non-bonded edge region, - a fitment sealing device, - a feed mechanism adapted and operated to feed said formed pouches, e.g. separate or as a string of interconnected pouches, e.g. to the fitment inserting device and the fitment sealing device, which devices may be located at one at the same station, - a fitment feeder adapted and operated to feed fitments to the fitment inserting device. 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 a fitment, e.g. a spout, being heat sealed between the walls at the top 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 the opening in the pouch, e.g. a non-bonded edge of the pouch using a sealing

-19- device. The filling can also, for example, be performed via a non-bonded edge region into which a fitment, e.g. a spout, is sealed at a later stage. For example, the filling is done via a spout of the pouch, 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, a pre-made spout supplied to a spout inserter device is part of a pre- made spout-closure assembly comprising the spout and a closure member closing said spout, so that after performing the sealing step(s) 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.

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, 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. 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.

-20- For example, the sealing device discussed herein is configured to establish a side or vertical seal of the pouch, e.g. side seals along opposite vertical sides of the pouch, e.g. in a horizontal form-fill-seal machine.

For example, the sealing device is configured to establish a side seal in a bottom gusset pouch, with said sealing seam extending across the triple point where the top of the gusseted portion adjoins the side of the pouch.

In an embodiment, all sealing devices of the production machine, including any fitment sealing device, 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 invention also relates to a method for the impulse sealing of two walls made from heat- sealable material, preferably metal-free heat-sealable film material, wherein use is made of a sealing station or a sealing device as described herein.

The invention also relates to a method for the production of collapsible pouches, wherein use is made of a sealing station, or a sealing device, and/or a production machine as described herein.

The invention also relates to a sealing station or device as described herein for use in the production of collapsible pouches.

The invention also relates to an impulse sealing station or device for use in the production of spouted collapsible pouches as described herein.

A second aspect of the present invention relates to a system comprising a sealing station configured to heat seal a wall made from heat-sealable film material, preferably metal-free heat-sealable film material, onto one another wall of heat-sealable material, e.g. another wall of heat-sealable film material, to create a sealed seam, 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 at least one of the first and second jaws,

-21- wherein the first jaw has a first front surface configured to contact an elongated seam region of a respective first wall made from heat-sealable material, wherein the second jaw has a second front surface configured to contact an elongated seam region of a respective second wall made from heat-sealable material, wherein at least the first jaw comprises at the respective front surface thereof at least one, e.g. a single elongated, impulse heatable member that extends along the respective front surface and that is covered by a heat-resistant non-stick covering, 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 the seam regions of the first and second walls are clamped against one another by the first and second jaws, and wherein the sealing station is configured to, in the clamped position, temporarily energize each impulse heatable member so as to generate an impulse of heat that is emitted by each heatable member, which impulse of heat seals the seam regions of the first and second walls to each other, wherein at least one of the first and second jaws is cooled by the cooling device after termination of the energizing of the heatable member, and wherein the actuator device is configured to move the first and second jaws into the opened position after the heatable element has cooled down, wherein the system further comprises a conveyance mechanism that is configured to convey the walls to be sealed along a path of conveyance in a continuous motion, said path at least extending along the 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 walls to be sealed during the impulse sealing cycle.

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 for the sealing, e.g. of the pouches, or string of interconnected pouches.

In the second aspect of the invention the 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.

29.

In the second aspect the invention the 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 at least one of the jaws comprises an inductor, and wherein the sealing station comprises a high frequency electric current source, which is connected to the inductor, 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 inductor, wherein the high frequency electromagnetic field induces eddy currents in the susceptor element generating an impulse of heat that is emitted by the susceptor element, which impulse of heat seals the seam region of the walls to each other.

In an embodiment of the second aspect of the invention 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.

The 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.

The second aspect of the invention also relates to a method wherein use is made of the system.

A third aspect of the invention relates to a sealing station configured to heat seal a wall made from heat-sealable film material, preferably metal-free heat-sealable film material, onto one another wall of heat-sealable material, e.g. another wall of heat-sealable film material, to create a sealed seam, 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 at least one of the first and second jaws,

23. wherein the first jaw has a first front surface configured to contact an elongated seam region of a respective first wall made from heat-sealable material, wherein the second jaw has a second front surface configured to contact an elongated seam region of a respective second wall made from heat-sealable material,

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 the seam regions of the first and second walls are clamped against one another by the first and second jaws, and wherein the sealing station is configured to, in the clamped position, temporarily energize each impulse heatable member so as to generate an impulse of heat that is emitted by each heatable member, which impulse of heat seals the seam regions of the first and second walls to each other, wherein at least one of the first and second jaws is cooled by the cooling device after termination of the energizing of the heatable member, and wherein the actuator device is configured to move the first and second jaws into the opened position after the heatable element has 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 front surface,

and wherein at least one of the first and second jaws comprises an inductor, preferably the first jaw comprises an inductor, wherein the inductor is electrically insulated from the susceptor element,

wherein, preferably, the inductor comprises an elongated inductor section at the rear side of the at least one susceptor element, and wherein the sealing station comprises a high frequency electric current source, which is connected to the inductor,

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

-24- inductor, thereby generating a high frequency electromagnetic field with the inductor, wherein the high frequency electromagnetic field induces eddy currents in the susceptor element generating an impulse of heat that is emitted by the susceptor element, which impulse of heat seal the seam regions of the walls to each other, and wherein the inductor and corresponding susceptor element, e.g. both arranged in the first 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.

The third aspect of the invention also relates to a method wherein use is made of the sealing station. Embodiments of the invention will be described by way of example only, with reference to the accompanying drawings. In the drawings: Figure 1 schematically shows a view in perspective of an embodiment of the pouch production according the invention, Figure 2 schematically shows an example of a standing pouch, Figure 3 schematically shows a triple point of the pouch of figure 2, Figure 4 schematically shows an embodiment of the sealing device according to the invention, Figure 5 schematically shows the susceptor element and inductor of figure 4, Figure 8 schematically shows a cross section of a jaw including the susceptor element and inductor, Figure 7 schematically shows a cross section of a jaw including the susceptor element, inductor, and resilient backing layer of the susceptor element, Figures 8A,B, C schematically shows the electromagnetic field generated by the jaw of figure 4 and the interaction with the susceptor element, Figure 9 shows an alternative design of the inductor, Figure 10 shows yet another alternative design of the inductor, Figure 11 illustrates schematically the operation of a continuous motion sealing device.

25. Figure 1 schematically illustrates an example of a pouch production machine and related operating method according to the invention for the production of collapsible pouches made from heat-sealable film material. The machine is also known a Form-Fill-Seal (FFS) machine, in particular in the depicted embodiment a horizontal FFS machine.

Throughout the figures, the pouch production machine is referred to with reference numeral

1. The pouch production machine 1 is configured to produce collapsible pouches 100, 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 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 machine 1, the film material 12 is unwound from the roll 11. The machine 1 comprises a bottom gusset folding device 13 to fold the film material 12 dispensed from a single roll into a folded shape, so that two pouch walls 101, 102 oppose one another and so that the bottom has a gusset as is well known in the art. In the depicted exemplary embodiment film material travels horizontally. The folding device 13 is configured to fold the film material 12 such 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, with first and second gusset portions in the bottom part. After folding, the film material travels along a bottom heat sealing station A with a heat sealing device 20. The bottom sealing device 20 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.

-28- Downstream of the first or bottom heat sealing device 20, the machine 1 comprises a second or side seam heat sealing station B with a heat sealing device 21.

The second heat sealing device 21 is aligned perpendicular to the horizontal direction (H) and is configured to provide a side seam in the pouch. As shown the side seam extends over at least a section of the height of the pouch, e.g. over the majority or even the entirety of the height of the pouch. For example, the actual height of the side seam made by sealing device 21 depends on the structure and operation of the bottom seal device 20.

As will be explained in more detail below, in an embodiment, the heat sealing device 21 may provide a side seam that extends over a so-called triple point. 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, here above the triple 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, here below the triple point. In the depicted embodiment, the film conveyance device 40, here comprising rollers driving the film material arranged downstream of device 21, 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 gusset bottom seal formations. Simultaneously, the film material 12 is held at a relevant location in front of the second heat sealing device 21 to form the lateral or side seam of the pouch 100.

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. Once the bottom seal formations and both side seams of the pouch have been formed, the machine opens the top of the pouch 100, more specifically opens the non-bonded upper edge. This may for example be done using suction gripper engaging the top regions of the walls 101, 102 and moving them apart. Once the top edge is opened, at station C a filling device 50, fills a product, e.g. a liquid and/or solid product, into the pouch 100 via the non-bonded upper edge.

27- Then, at a top edge sealing station E, the non-bonded upper edge of the pouch 100 is sealed after the filling, by upper edge sealing device 200. A cutting device 60 is provided to separate a filled and hermetically sealed pouch 100 from string of interconnected pouches. Figures 2 and 3 schematically show a gusset bottom pouch 100 and the so-called triple point.

The pouch has side walls 101, 102 and a gusset bottom 103 with first a second gusset portions 101a, 102a that are folded along inner fold line 104 by folding device 13.

The pouch 100 is sealed in the gusset bottom 103 by the sealing device 20 which is embodied to make a heat seal 107 between the first pouch wall 101 and the first gusset portion 101a that is directly inward thereof and a heat seal between the second pouch wall 102 and the second gusset portion 102a that is directly inward thereof.

The pouch is further sealed, ahead of any filling, along first and second side seams 105, 106, also called lateral seams.

The pouch is further sealed along upper edge region 113, e.g. after the product has been filled into the pouch via the edge region 113.

As shown in figure 3 the triple point is where there are two walls 101, 102 of the pouch 100 to be joined on one side of the point, here the part of the side seam above the triple 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, here the part of the side seam below the triple point.

In figure 4, an embodiment of a sealing station E is displayed schematically in more detail, partially in exploded-view along with the pouch 100 that has already been sealed in the upper edge region thereof.

The sealing station E comprises: - a heat sealing device comprising a first jaw 210 and a second jaw 220,

-28- - 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. The first jaw 210 has a first front surface configured to contact the edge region of a respective first wall 101 of the pouch. The second jaw 220 has a second front surface configured to contact the edge region of a respective second wall 102 of the pouch.

The first and second front surfaces are straight or rectilinear when seen from above and are generally planar. Each of the first and second jaws 210, 220 comprises at the respective front surface thereof one single elongated, heatable member 212, 222 that extends along the respective front surface and that is covered by a heat-resistant non-stick covering (not shown in figure 4 for clarity). The sealing station E is configured to perform a sealing cycle, so that the upper edge region of the pouch 100 is hermetically sealed. 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 one another by the planar front surfaces of the first and second jaws 210, 220. The sealing station E is configured to perform a sealing cycle. Once the jaws 210, 220 have been moved into the clamped position as indicated above, 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 alternating 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 each other in the upper edge region.

-29- 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. 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. 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. It is shown in figures 4 and 5, that in each jaw 210, 220 there is just one pair of elongated inductor sections 2214, 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. The provision of just one pair of inductor sections 2214, b is a preferred embodiment for a top seal of a pouch. In an embodiment, the elongated inductor section 2214, b is made from a metal, e.g. of copper.

It is shown in figures 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. It is shown in figures 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. It is shown in figures 4 and 5, that the uniform cross-section elongated inductor section 2214, b 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 222 and the elongated inductor section 2214,b. This arrangement enhances uniformity of the development of heat in the susceptor element.

-30- The horizontal slit 221c can be air slit or a slit filled with electrically insulating material. 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. 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 figures 8A,B, and C. Figure 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.

Figure 8C illustrates the strength and distribution of the field of figure 8B in a perspective view. 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. It is shown in figures 4 and 5, that the susceptor element 222 extends, seen in a view onto the front surface of the jaw, over the horizontal slit 221¢ between the parallel inductor sections 221a,b. It is shown in figures 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. It is shown in figures 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.

It is shown in figures 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%

-31- of the height of the single pair of inductor sections 2214, 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.

Itis shown in figures 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. It is shown in figures 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. It is shown in figures 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.

It is shown in figure 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.

It is shown in figures 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.

-39. It is shown in figures 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.

In an embodiment the at least one elongated inductor section 2214, 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 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 “h” that is greater than the thickness “t” of the inductor section. This arrangement allows to limit the thickness, which allows for efficient cooling.

Itis shown in figures 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.

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.

In an embodiment, at least one cooling fluid duct 214 extends along the at least one conductor section 221a, b that extends along the rear side of the susceptor element 222.

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.

-33- 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°C before opening, e.g. to below 40°C.

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.

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.

For example, the susceptor element 212, 222 is made of, or comprises, aluminium, nickel, silver, stainless steel, and/or nickel-chrome.

Itis shown in figures 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.

Itis shown in figures 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.

Itis shown in figure 4, that the planes of the susceptor elements 212, 222 are parallel to one another. The preferred smoothness of the fronts of the jaws, so the absence of a relief that locally holds the wall of film material away from the front face and creates air pockets between the wall 101, 102 and the front surface, 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 lightly clamped walls 101, 102.

-34- It is shown in figures 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 figure 4, that the strip has a constant height over its length.

It is shown in figures 4 and 5, that the susceptor element 212, 222 strip lacks apertures over its extension. It is shown in figures 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.

It is shown in figure 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 0.3 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 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.

It is shown in figures 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 0.3 and 0.5 mm. For example, the strip is made of aluminium material.

In embodiments, the frequency of the electric current supplied by source 250 to the inductors 211, 221 of the jaws 210, 220 is between 250 KHz and 750 KHz.

Itis shown in figures 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

-35- thickness of the susceptor element is envisaged to be more than this skin depth, yet not too much for the reason addressed herein.

It is shown in figure 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.

Preferably, the entire spacing between the rear of the susceptor element and the neighbouring inductor section(s) is filled with electrically insulating material.

Figure 8 illustrates that the spacing between the rear of the susceptor element 222 and the neighbouring inductor section 221 is filled with multiple 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.

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 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.

Figure 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.

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

-36- 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. 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.

It is shown in figures 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 or devoid of any relief that would locally keep the film material away from the front surface, so lacking for example one or more ribs, bosses, etc.

Itis shown in figure 4, that the jaws 210, 220 are configured, e.g. have a length, so that the entire non-bonded edge region is sealed in one cycle by the operation of the jaws. This avoids the needs for additional sealing actions along said edge region.

It is shown, that both jaws 210, 220 have a main body 22043, 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.

One or more cooling ducts 214 are provided, e.g. machined, in a main body.

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.

-37- 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°C and at most any of 200°C, 300°C, 400°C, or 500°C measured on the susceptor element. 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. 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. It is noted that control of the temperature that is reached during the impulse heating may be done on the basis of monitoring the supply of electrical power to the inductors.

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. It will be appreciated that the sealing station E may also be arranged to provide a vertical seam in the pouch, e.g. the sealing device 21 being embodied as the sealing station E described above.

As discussed, in case of a gusset bottom pouch, e.g. standing pouch, a triple point as shown in figure 3 will be present in the vertical side of the pouch. For a sealing device according to the present invention and envisaged to provide a seal that extends the triple point, the embodiment as illustrated in figure 7 may be advantageous.

In such a situation it can be advantageous to provide a resilient backing layer 228, e.g. of vulcanized silicone rubber, 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 0.5 and 2.0 millimeter, e.g. between 0.5 and

1.0 mm. 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.

-38- Figure 9 shows an embodiment, wherein the inductor 221° of a jaw is designed to create a rather wide sealing seam, e.g. a vertical or side seam to two adjacent pouches ahead of the pouches being separated by a cut through this sealing seam. E.g. a wide seal at station B of figure 1. For example, a sealing seam having a width of between 15 and 40 millimeters.

Instead of a single pair of elongated inductor sections, the inductor 221’ has more than two inductor sections in a parallel arrangement, e.g. at least four or even six as shown here by way of example. It is envisaged that the susceptor 222 lies over the inductor 221’ as explained above. The inductor sections 221’a,b,c,d,e,f are connected in series and arranged in a serpentine arrangement, with the inductor elements being generally in a common plane. Between adjacent conductor sections 221'a,b,c,d,e,f a slit is present as discussed herein. The free ends of the first section 221'a and of the last section 221'f form the terminals of the inductor 221’ for connection to the current source. The thickness of the inductor sections, as preferred, is less than the height or width of each of them, so as to facilitate rapid cooling of the inductor.

The figure 10 depicts an embodiment wherein the thickness of the inductor sections 221"a,b,c,d exceeds the height or width of them. Whilst this creates an effective field, cooling is less effective than with the embodiment of figure 9.

The inductor 221'comprises multiple nested C-shaped inductor elements, here two, 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.

In figure 11, the impulse sealing of top edge regions of a first pouch wall 101 and of a second pouch wall 102, is displayed schematically by means of steps (a) — (e).

Inthe 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 figure 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.

-30- The cycle is started with step (a), shown on the left side of figure 11. The first jaw 210 and the second jaw 220 are initially in a position spaced from the pouch walls 101, 102 that may still be somewhat opened in in upper region.

Upon operation of the first actuator device 201, the first jaw 210 is moved towards its clamped position, wherein the first jaw 210 comes in contact with the first pouch wall 101. Similarly, the second jaw 220 is moved towards its clamped position by the second actuator device 202, wherein the second jaw 220 comes in contact with the second pouch wall 102. In the respective clamped positions, the first pouch wall 101 and the second pouch wall 102 are lightly clamped onto one another in the region of the seam to be formed along the upper edge. The clamping is lightly as no pressure is involved in the sealing process. 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. Under the influence of the heat impulses, the first pouch wall 101 and the second pouch wall 102 are locally fused with each other along the seam, in order to fuse the pouch walls 101, 102 against each other. 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. 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. 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).

-40- After moving the jaws 210, 220 back during step {e), the cycle is repeated, starting with step (a) again.

It will be appreciated that the path of the jaws 210, 220 can be of any suitable shape, e.g. circular, oval, linear, etc.

Claims

-41 - CONCLUSIONS

1. Sealing station, adapted to heat seal a wall of heat-sealable film material, preferably metal-free heat-sealable film material, against another wall of heat-sealable material, for example another wall of heat-sealable film material, around a sealed seam. wherein the sealing station comprises: - 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 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 adapted to contact an elongated seam region of a respective first wall of heat-sealable material, the second jaw having a second front surface, adapted to contact an elongated seam region of a respective second wall of heat sealable material, wherein at least the first jaw has on its respective front surface at least one, for example a single elongated, pulse-heatable element extending along the respective front surface and covered with a heat-resistant non-stick layer, the sealing station being arranged to perform an impulse sealing cycle wherein the actuator device is arranged to bring the first and second jaws into the clamped position so that the seam regions of the first and second walls are clamped together by the first and second jaws, and wherein the sealing station is arranged to, in the clamped position, momentarily activating each pulse heatable element to generate a heat pulse emitted from each heatable element, the heat pulse sealing the seam regions of the first and second walls against each other, at least one of the first and second jaws is cooled after the activation of the heatable element has ended, and wherein the actuator device is arranged to move the first and second jaws to the open position after the heatable element has cooled,

-42- wherein each impulse heatable element is a susceptor element comprising electrically conductive material, the susceptor element having a back side remote from the respective front surface, and at least one of the first and second jaws comprising an inductor extending along the respective front surface and which is electrically isolated from the respective susceptor element, and which has an elongated inductor portion at the rear of the respective at least one susceptor element, and wherein the sealing station comprises a high frequency electrical power source connected to the inductor, the sealing station being such arranged that, during the impulse sealing cycle, the electrical power source is controlled to temporarily supply a high-frequency electrical current to the inductor, thereby generating a high-frequency electromagnetic field with the inductor, whereby the high-frequency electromagnetic field is eddy current and causes in the susceptor element, which generates a heat pulse emitted from the susceptor element, the heat pulse heat seals together the seam regions of the walls.

The sealing station of claim 1, wherein the at least one elongated inductor portion is a fixed cross-section metal inductor portion, having a constant cross-section along its length along the profiled front surface of the respective jaw.

The sealing station of claim 1 or 2, wherein the elongated inductor portion, viewed in a plan view of the jaw, has a shape that conforms to the front surface of the jaw and maintains a uniform distance between the susceptor element and the elongated inductor portion.

A sealing station according to any one of claims 1 to 3, wherein the inductor of a jaw comprises a plurality of elongated inductor sections that are parallel to each other.

A sealing station according to any one of claims 1 to 4, wherein the inductor of a jaw comprises a plurality of elongated inductor sections parallel to each other and spaced apart by a gap, for example an air gap or a gap filled with a gap. electrically insulating material, where, for example, only a pair of elongated inductor portions are provided which are parallel to

43. are spaced apart and spaced from each other by a gap disposed proximate the rear of the susceptor element.

Seal station according to claim 5, wherein the gap between adjacent inductor parts has a height of between 0.01 and 5 mm, preferably between 0.1 and 2 mm.

A sealing station according to claim 5 or 6, wherein the susceptor element, when viewed in a view of the front of the jaw, extends across the gap between the parallel elongated inductor portions and overlaps in that view with each of the parallel inductor portions.

The sealing station of any of claims 5 to 7, wherein the susceptor element is configured as a single strip that extends across the gap between the parallel elongated inductor portions and overlaps in that view with each of the parallel inductor portions.

The sealing station of any one of claims 1 to 8, wherein the inductor of a jaw is configured such that in a pair of adjacent and parallel inductor sections disposed at the rear of the susceptor element, current flows in opposite directions through the inductor sections.

Sealing station according to any one of claims 1 to 9, wherein the at least one elongated inductor section has a thickness of between 1.0 and 4.0 mm, viewed perpendicular to the front surface of the jaw, for example between 1.5 and 3.0 mm.

The sealing station of any of claims 1 to 10, wherein at least one coolant line extends along the at least one inductor portion extending along the rear of the susceptor element.

Sealing station according to any one of claims 1 to 11, wherein the susceptor element is made of a metal material, for example a metal or a metal alloy, for example a thin metal strip.

A sealing station according to any one of claims 1 to 12, wherein the susceptor element is configured as a strip with opposite front and rear major surfaces defining 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.

40

-44 -

Sealing station according to any one of claims 1 - 13, wherein the susceptor element, for instance designed as a strip, has a thickness of between 0.01 mm and 5 mm, preferably between 0.05 and 2 mm, more preferably between 0.08 and 0.8 mm, for example from between 0.3 and 0.5 mm.

A sealing station according to any one of claims 1 to 14, wherein the jaw is provided with a single continuous susceptor element designed as a strip, for example of metal, with a height or width of the strip of between 3 and 40 millimeters, for example between 10 and 30 millimeters, and with a thickness of between 0.08 and 0.8 mm, for example between 0.3 and 0.5 mm.

A sealing station according to any one of claims 1 to 15, wherein the jaw is provided with a resilient backing layer behind the susceptor element, allowing the front of the jaw to adapt to a local variation in the number of film material walls, e.g. for sealing across a triple point in a yellow area of a pouch.

A sealing station according to any one of claims 1 to 18, wherein the distance between the back of the susceptor element and the adjacent inductor portion (s) is at least 0.025 mm, or 0.05 mm, or 0.1 mm and at most 3.0 mm, or 2.0 mm, or 1.0 mm.

A sealing station according to any one of claims 1 to 17, wherein the distance between the front surface of the jaw and the susceptor element is at least 0.025 mm, or 0.050 mm, and at most 2.0 mm, or 1.0 mm, or 0.5 mm, wherein, preferably, the gap is filled with one or more layers of electrically insulating material, for example with at least one layer of Kapton and one layer of Teflon as an anti-stick layer forming the front surface of the jaw.

A sealing station according to any one of claims 1 to 18, wherein the front surface is smooth in an area of contact with the walls of film material.

A sealing station according to any one of claims 1 to 19, wherein the jaws are arranged, for example having a length, such that the entire disconnected edge area is closed in a single cycle by the action of the jaws.

Sealing station according to any one of claims 1 - 20, wherein the sealing device is arranged to provide a heat impulse with the susceptor element of between at least 150 ° C and at most 200 ° C, 300 ° C, 400 ° C , or 500 ° C, measured on the 40 susceptor element.

- 45.

Sealing station according to any one of claims 1 to 21, wherein the duration of the heat pulse is between 10 and 1000 milliseconds, for example between 20 and 500 milliseconds, for example between 75 and 400 milliseconds.

A sealing station according to any one of claims 1 to 22, wherein the cycle comprises a clamped cooling phase immediately following the heat impulse, during which the jaws are held in the clamped position, wherein the clamped cooling phase can have a duration of between 200 and 800 milliseconds, for example between 300 and 600 milliseconds.

24. Production machine for the production of collapsible pouches, the pouches each having walls made of heat-sealable film material, preferably metal-free heat-sealable film material, the production machine comprising a sealing station arranged to heat-seal the walls against each other. sealing to form a closed seam of the pouch, the sealing station being configured according to any one of claims 1 - 23.

Production machine according to claim 24, wherein the sealing station is arranged to effect a side or vertical seam of the pouch, for example side seams along opposite vertical sides of the pouch, for example in a horizontal form-fill-seal machine, for example, wherein the sealing station is arranged to create a side seam in a bottom gusset pouch, the side seam extending over the triple point where the top of the coveted portion is adjacent to the side of the pouch.

26. A method of forming a sealed seam by heat sealing a wall made of heat-sealable film material, preferably metal-free heat-sealable film material, against another wall of heat-sealable material, for example another wall of heat-sealable foil material, wherein use is made of a sealing station according to any one of claims 1 - 23.

27. A method for the production of collapsible pouches, wherein use is made of a production machine according to claim 24 or 25.