Production of a folding pouch

Abstract

The machine for producing collapsible pouches includes an impulse sealing device with first and second jaws that contact the bottom regions of the pouch walls. Each jaw includes a susceptor element comprising a conductive material, the front surface of which is shaped as an inverted T for sealing the side and bottom edges of two adjacent interconnected pouches. Each jaw includes an inductor, which is insulated from the susceptor element. The machine includes a high-frequency current source connected to the inductor. The jaws include a device for cooling the inductor and the susceptor element. The machine is operated during a cycle to seal the bottom regions of the pouch walls, with the current source transiently delivering high-frequency current to the inductor, which generates a high-frequency electromagnetic field. The electromagnetic field induces eddy currents in the susceptor element, thereby generating a thermal impulse that is radiated, sealing the bottom regions of the pouch walls together.

Description

Technical Field

[0001] The present invention relates to the production of foldable pouches.

Background Art

[0002] Regarding the production of foldable pouches, it is known to use a production machine having a sealing station, and the sealing station is configured to heat-seal the bottom region of the pouch in an interconnected string of pouches made from a heat-sealable film material to form the bottom of the pouch. Also, pouch production machines are known, and in an embodiment, a bottom gusset is formed to produce a foldable upright pouch.

[0003] In a well-known embodiment, the sealing station includes a sealing device having a first jaw and a second jaw, and an actuator device, and the actuator device is configured to move the first and second jaws relative to each other between an open position and a clamp position. In this sealing device, each of the jaws has a front surface, and the front surface is configured to contact the bottom region of each of the first or second wall portions of the pouch. The front surface of each jaw defines a planar surface portion. The jaws of the known sealing device are continuously (e.g., electrically) heated to a temperature suitable for heat-sealing. This is known as the hot bar sealing technique. During operation, the continuously heated jaws are moved to the clamp position with the pouch wall portions between the jaws. The maximum temperature of the heated jaws is generally limited by the characteristics of the film material of the pouch. Time, pressure, and temperature are the main parameters governing this heat-sealing process. Pressure is generally quite important to achieve proper sealing.

[0004] For example, several developments have been made over the years considering the conditions during heat sealing of this general type of practice in the bottom region of the pouch in order to heat seal a pouch having a bottom gusset. For example, Patent Document 1 discloses a pouch production system including a continuously heated jaw for sealing the bottom gusset region of the pouch.

[0005] In Patent Document 1, it is further disclosed that during the sealing cycle, a string of interconnected pouches is positioned between a first jaw and a second jaw. The heated jaw here partially protrudes over the bottom gusset regions of two adjacent interconnected pouches. The jaw is configured to simultaneously seal a part of the bottom gusset region of the first pouch and, in one sealing cycle, is configured to seal a part of the bottom gusset region of the adjacent and still interconnected second pouch. Additionally, the jaw is also configured to seal the adjacent side edges of both adjacent interconnected pouches. Thus, during a single sealing cycle, the sealing station is configured to provide a single triple-point gusset seal in each of two adjacent interconnected pouches.

[0006] In the field of pouch production, for example, it is known to use impulse sealing devices such as those provided by ROPEX Industrie-Elektronik GmbH, Bietigheim-Bissingen, Germany. In known embodiments of such impulse sealing devices, at least one of the jaws has a single elongated impulse-heatable resistor band, which extends along the front surface of the jaw and is covered by a heat-resistant charring-preventing coating (e.g., Teflon® tape). The device is configured to perform an impulse sealing cycle, and the actuator device is configured to bring the first and second jaws to a clamping position, such that, for example, two wall portions of a heat-sealable film material are therebetween. The sealing device is configured to temporarily pass an electric current through the resistor band at the clamping position, so as to generate an impulse of heat released by the resistor band. This short-duration heat impulse seals the wall portions to each other. The jaws cool after the excitation of the resistor band ends, which is assisted by the operation of an associated cooling device. The actuator device is configured to move the first and second jaws to an open position after cooling has been achieved. The temperature of the resistor band can be raised very quickly from room temperature or slightly elevated temperature to 300 °C or thereabouts in a practical embodiment, and thus generally very quickly to a very high temperature, which is maintained for only a very short duration. The impulse sealing approach is discussed, for example, in Patent Document 2.

[0007] The above-described impulse sealing device has the drawback that it cannot accurately control the temperature distribution across the resistor band during a relatively short pulse time. As a result, the sealing characteristics may not be accurate across the entire contour of the area to be sealed. In particular, with respect to sealing the bottom region of a foldable pouch, for example, with respect to sealing the bottom gusset portion of a foldable upright pouch, such quality is essential to achieve a sufficiently low production failure rate.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention is to provide means for improving the production of a foldable pouch, preferably, improving the production of a foldable upright pouch including a bottom gusset.

[0010] An object of the present invention is to provide means for enhancing the quality of a seal obtained in the film material of the pouch wall portion at its bottom region, for example, in the bottom gusset region, and at the triple point of a bottom gusset type foldable upright pouch.

Means for Solving the Problems

[0011] The present invention relates to a production machine for the production of foldable pouches, preferably for the production of foldable upright pouches including a bottom gusset, said pouches each having a wall part made of a heat-sealable film material, preferably a metal-free heat-sealable film material, the production machine including a sealing station, the sealing station being configured to heat-seal the bottom regions of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material. The sealing station - includes an impulse sealing device including a first jaw and a second jaw; - an actuator device configured to move the first and second jaws relative to each other between an open position and a clamping position; - a cooling device configured to cool at least one, preferably each, of the first and second jaws and includes The first jaw has a first front surface, the first front surface being configured to contact the bottom region of the first wall part of each of the two adjacent pouches. The second jaw has a second front surface, the second front surface being configured to contact the bottom region of the second wall part of each of the two adjacent pouches. At least one, preferably each, of the first and second jaws includes at least one impulse-heatable member on its respective front surface, the impulse-heatable member extending along the front surface, the impulse-heatable member being covered by a heat-resistant anti-burning coating. During operation, the production machine is configured such that a string of interconnected pouches is positioned between the first and second jaws, and the impulse-heatable members of the first and second jaws are configured to at least partially protrude over the bottom regions of two adjacent pouches, respectively. The sealing station is configured to perform an impulse sealing cycle, the actuator device is configured to bring the first and second jaws to the clamping position, and in the bottom region, the first and second wall portions are clamped to each other by the front surfaces of the first and second jaws. The sealing station is configured to temporarily excite one or more impulse-heatable members at the clamping position, generating an impulse of heat released by each of the one or more impulse-heatable members. The one or more heat impulses seal at least a part of the bottom regions of the first and second wall portions of two adjacent interconnected ports to each other. The first and second jaws and at least one or more of the impulse-heatable members are cooled by the operation of a cooling device after the end of the excitation supported therein. The actuator device is configured to move the first and second jaws to the open position after the one or more impulse-heatable members have been cooled. Each of the impulse-heatable members is a susceptor element containing a conductive material, and the susceptor element has a rear side portion facing away from its respective front surface. Each of the susceptor elements has a front surface shaped at least as an inverted T, and the heat impulse is configured to seal at least a part of the side edge region of two adjacent interconnected ports and at least a part of the bottom edge region of two adjacent interconnected ports. At least one, preferably each, of the first and second jaws includes an inductor, the inductor is electrically insulated from its respective susceptor element, and the inductor includes an elongated inductor section that extends along its respective front surface at the rear side portion of its respective at least one susceptor element. The sealing station includes a high-frequency current supply source, which is connected to the inductor of at least one (preferably each) of the first and second jaws. In the impulse sealing cycle, the sealing station is configured such that the current supply source is operated to temporarily feed high-frequency current to one or more inductors, thereby generating a high-frequency electromagnetic field by the one or more inductors. The high-frequency electromagnetic field induces eddy currents in each susceptor element and generates heat impulses released by the susceptor elements. The one or more heat impulses seal the bottom region of the pouch, providing a production machine.

[0012] At the rear side of at least one susceptor element, preferably very close to the rear side and along the front surface, due to the extension of at least one elongated inductor section, heat development occurs over the extension of the front surface of the jaw in an attractive manner (especially in a fairly uniform manner). The elongation of the inductor section contributes to the homogeneity of the current density in the inductor section compared to, for example, the coiled shape of the inductor section or another fairly irregular shape. This homogeneity is converted into the homogeneity of the high-frequency field and thereby into the homogeneity of the impulse heating of the susceptor element.

[0013] Compared to resistance heating in known impulse heating devices, impulse heating by the inductor element and the susceptor element allows for more accurate control of the heating. The latter contributes to reliable and effective heat sealing between the wall portions of the film material.

[0014] Between the sealings of the foldable porch without a bottom gusset, the porch wall portions are clamped directly against each other in the bottom region. In this specification, it may be sufficient that one of the first and second jaws is provided with a susceptor element and an inductor, and the other jaw is simply embodied and operated as a passive counter-jaw.

[0015] In the production of a foldable porch with a bottom gusset, the string of interconnected porches fed to the sealing station is generally in a W-shape as known in the art, having a first wall portion, a first bottom gusset portion, a second bottom gusset portion, and a second wall portion. Also, as known in the art, so-called triple points exist at each of the side edges of the porch, and above the triple points, the first and second wall portions are in direct contact with another wall portion, and below the triple points, the two gusset portions are positioned between the first wall portion and the second wall portion. Thus, at the triple points, the thickness varies between twice the wall thickness and four times the wall thickness. Near this transition portion, sealing by existing techniques is notoriously difficult. At the clamping position, the first and second wall portions and the bottom gusset portions of two adjacent interconnected porches are clamped against each other by the front surfaces of the first and second jaws.

[0016] In a machine for the production of a bottom gusset type porch, both the first and second jaws are each provided with a susceptor element and an inductor, and are adapted to seal the first gusset portion against the first wall portion and the second gusset portion against the second wall portion.

[0017] In certain embodiments, both the first and second jaws are provided with susceptor elements and inductors. As used herein, in certain embodiments, the inductors can be simultaneously excited. However, it is also possible to have non-simultaneous excitation of the inductors. This can be non-simultaneous during a single cycle. When sealing a pouch lacking a bottom gusset, it is possible to envision that one jaw is operated for impulse sealing during one cycle and the other jaw is operated only during the next cycle. The reason is that, for example, providing a thermal impulse by one jaw can provide sufficient heat to achieve a desired heat seal in the bottom region.

[0018] Exciting the inductor during an impulse sealing cycle can consist of a single short-duration high-frequency current passed through the inductor. It can also be done differently (e.g., successively in even shorter periods), for example, different intensities of current are passed through the inductor during a single impulse sealing cycle.

[0019] Providing an inductively impulse heatable member can provide that the startup time (e.g., the time it takes for the sealing station to become operable from an inactive state) is quite limited. Compared to known sealing stations with continuously heated jaws, it is not necessary to bring the jaws close to the sealing temperature, which in prior art sealing stations requires up to 30 minutes. Instead, in the approach of the present invention, the jaws of the sealing station can reach a steady state temperature in less time (typically between only 1 and 2 minutes) after being modified, for example, for different packaging, such that the sealing station makes different types of seals.

[0020] The homogeneity of the heat sealing and impulse processes enables having the minimum clamping force of Joe at the clamping position, which is much smaller than, for example, that by a conventional continuously heated Joe. The clamping force can effectively only serve to ensure close surface contact between the pouch wall portion and the gusset portion (when present) positioned inwardly.

[0021] Regarding the sealing of the bottom region of the pouch with a bottom gusset, the clamping force can be selected to be greater than, for example, the clamping force for welding the bottom region without a bottom gusset, for example, from the perspective of reliably discharging air from the clamped portion of the pouch at the triple point.

[0022] It has been found by the applicant that impulse heating by an inductor and susceptor element is particularly preferred for sealing, among other things, the bottom gusset of the pouch.

[0023] In the production of a bottom gusset type pouch, precise control of heating provides that sufficient heat is provided to seal each gusset portion to its respective first or second wall portion in the portion of the pouch at and below the triple point, and also provides that the amount of heat does not become too large to prevent the gusset portions from being welded to each other.

[0024] The inverted T-shaped susceptor element includes three elongated susceptor parts, which are interconnected at the central portion of the susceptor element. During operation, the first of the elongated susceptor parts protrudes towards the upper end of the pouch and protrudes over the side edges of two adjacent interconnected pouches, for example, at least over the lower portion of the side edges. During operation, this upwardly elongated susceptor part thereby at least partially seals the side edges of the adjacent interconnected pouches.

[0025] In an embodiment, to provide a substantially straight side seal for the pouch, this upwardly elongate susceptor part can be substantially straight. In an alternative embodiment, to provide a side seal for the pouch having a curved or wavy shape, the upwardly elongate susceptor part can have a curved or wavy shape.

[0026] The T-shaped susceptor element can be embodied to provide a rounded bottom corner seal as shown herein. This is advantageous not only for a foldable upright pouch with a bottom gusset, but also for a simple foldable pouch. The reason is that, for example, the rounded bottom corners can enable more convenient filling of the pouch and / or a more attractive aesthetic for the filled pouch (e.g., having fewer wrinkles in the pouch walls when filled). In another embodiment, the shape of the seal obtained at the bottom and corners is of the kind known as a K-seal stand-up pouch.

[0027] Each of the other elongate susceptor parts has at least a component that projects laterally (e.g., in the lateral and downward directions) away from the upwardly elongate susceptor part over the bottom region of each respective pouch. In operation, each of these laterally oriented elongate susceptor parts thereby seals at least a portion of the bottom region of each adjacent interconnected pouch.

[0028] The present invention further provides a production machine for the production of foldable pouches, at least as claimed in claim 1, wherein the sealing station configured to heat-seal the bottom regions of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material is replaced by a sealing station configured to heat-seal the upper regions of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material, each of the susceptor elements having a front surface shaped at least as an inverted T, the heat impulse being configured to seal at least a part of the side edge regions of two adjacent interconnected pouches and also at least a part of the bottom edge regions of two adjacent interconnected pouches, which feature is replaced by the feature that each of the susceptor elements has a front surface shaped at least as a T, the heat impulse being configured to seal at least a part of the side edge regions of two adjacent interconnected pouches and also at least a part of the upper edge regions of two adjacent interconnected pouches.

[0029] The present invention further provides a production machine for the production of foldable pouches, as claimed at least in claim 1, wherein the sealing station configured to heat-seal the bottom regions of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material is replaced by a sealing station configured to heat-seal the upper regions, bottom regions, and intermediate side regions of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material, each susceptor element having a front surface shaped at least as an inverted T, the heat impulse being configured to seal at least a portion of the side edge regions of two adjacent interconnected pouches and also configured to seal at least a portion of the bottom edge regions of two adjacent interconnected pouches, which feature is replaced by the feature that each susceptor element has a front surface shaped at least as an I, the heat impulse being configured to seal at least a portion of the side edge regions of two adjacent interconnected pouches, configured to seal at least a portion of the upper edge regions of two adjacent interconnected pouches, and also configured to seal at least a portion of the bottom edge regions of two adjacent interconnected pouches.

[0030] In one embodiment, the elongated inductor section is made of metal, for example, made of copper.

[0031] In an embodiment, at least one elongated inductor section is, for example, a solid cross-section metal made of copper (copper is preferred) or other (preferably, a high conductivity material inductor section). This arrangement makes it possible to avoid excessive fluctuations in the current density in the inductor section, for example, compared to an inductor section with a hollow interior, thereby making it possible to avoid undesirable fluctuations in the generated field.

[0032] In an embodiment, at least one elongated inductor section has a constant cross-section along its length along the front surface of each joe, and preferably has a solid cross-section. This design avoids excessive variations in the current density in the inductor section (which could otherwise occur at the location where the cross-section changes), thereby avoiding undesirable variations in the generated field.

[0033] In an embodiment, the elongated inductor section with a uniform cross-section has a shape corresponding to the front surface of the joe as viewed in the top view of the joe, maintaining a uniform distance between the susceptor element and the elongated inductor section. This arrangement enhances the uniformity of heat development in the susceptor element.

[0034] In an alternative embodiment, the inductor has a non-constant cross-section (e.g., locally has a cross-section narrower than the nominal cross-section) and is capable of locally increasing the current density for high-frequency currents, so as to locally increase the intensity of the heat impulse emitted by the susceptor element.

[0035] In an embodiment, the distance between the inductor and the susceptor element can vary locally, for example, from a uniform nominal distance between the inductor and the susceptor element. The locally narrower distance causes, for example, the electromagnetic field in the susceptor to increase locally, so as to locally increase the intensity of the heat impulse emitted by the susceptor element.

[0036] In an embodiment, the distance between the inductor and the susceptor element can vary locally from a uniform (e.g., nominal) distance between the inductor and the susceptor element. The locally narrower distance causes, for example, the electromagnetic field in the susceptor to be increased locally, so as to locally increase the intensity of the heat impulse emitted by the susceptor element.

[0037] This local variation in the cross-section of the inductor and in the distance between the inductor and the susceptor element can be beneficial in the sealing of the side seal across the triple point in the bottom gusset port. Above the triple point, two layers of heat-sealable film material are sealed, while below the triple point, four layers of heat-sealable film material are sealed, and a larger amount of heat is required to obtain a seal with sufficient quality.

[0038] Accordingly, the cross-section of a part of the inductor configured to protrude above the triple point can be selected to be larger than the cross-section of a part of the inductor configured to protrude below the triple point, so as to achieve a larger current density below the triple point.

[0039] Similarly, above the triple point, the distance for the inductor to protrude between the inductor and the susceptor element can be selected to be larger than the distance between the inductor and the susceptor element below the triple point, so as to achieve a larger current density below the triple point.

[0040] In an embodiment, Joe's inductor includes a plurality of elongated inductor parts connected in series at the central portion of the inductor, for example, three elongated inductor parts. Thereby, the first of the elongated inductor parts protrudes above the upwardly elongated susceptor part. Thereby, each of the second and third elongated inductor parts protrudes above the respective laterally elongated susceptor part. Thus, the shape of the inductor substantially corresponds to the shape of the susceptor element and is adapted to provide a uniform distribution of eddy currents in the susceptor element.

[0041] In an embodiment, Joe's inductor includes a plurality of elongated inductor sections, and the plurality of elongated inductor sections are parallel to each other.

[0042] In an embodiment, Joe's inductor includes a plurality of elongated inductor sections, the elongated inductor sections extend along each other, and the elongated inductor sections are spaced apart from each other by slits, for example, air slits, or slits filled with an electrically insulating material.

[0043] In an embodiment, the inductor includes three elongated inductor sections. The first elongated inductor section extends across a first (e.g., horizontal) downward elongated inductor part and an upward elongated inductor part. The second elongated inductor section extends across the upward elongated inductor part and a second (e.g., horizontal) downward elongated inductor part. The third elongated inductor section extends across the second (e.g., horizontal) downward elongated inductor part and the first (e.g., horizontal) downward elongated inductor part. The elongated inductor sections extend parallel to each other and are spaced from each other by slits, thereby following the inverted T-shape of the susceptor element and thereby being disposed adjacent to the rear side portions of the susceptor element.

[0044] In an embodiment, the slit between adjacent inductor sections disposed adjacent to each other extends between 0.01 mm and 5 mm, more preferably between 0.1 mm and 2 mm.

[0045] The presence of the slit between adjacent elongated inductor sections allows for a desirable concentration of the field generated by the inductor of Joe. In certain embodiments, the susceptor element extends over the slit between the parallel inductor sections when viewed in a figure of the front surface of Joe.

[0046] In some embodiments, the susceptor element extends over a slit between parallel elongated inductor sections when viewed in a front surface view of the joe, and in said view, overlaps with each of the parallel inductor sections. In some embodiments, the susceptor element extends over the entire parallel inductor sections. In another embodiment, the amount of overlap between the susceptor element and the parallel inductor sections is limited. For example, the susceptor element overlaps with each inductor section over less than about 25%. The size of the susceptor element is generally selected according to the seal to be fabricated.

[0047] In some embodiments, the susceptor element is embodied as an inverted T-shaped strip, the strip extending over a slit between parallel elongated inductor sections, and in said view, overlapping with each of the parallel inductor sections.

[0048] Since the strip-shaped susceptor element extends over the slit, the field generated by the inductor is advantageously concentrated in the susceptor element.

[0049] In some embodiments, the inductor of the joe is embodied such that current flows in the same direction through the inductor sections in a pair of adjacent parallel inductor sections disposed at a rear side portion of the susceptor element.

[0050] In some embodiments, the inductor of the joe is embodied such that current flows in opposite directions through the inductor sections in a pair of adjacent parallel inductor sections disposed at a rear side portion of the susceptor element.

[0051] In one embodiment, Joe's inductor has an inverted T shape and includes first, second, and third inductor sections, which are interconnected in series, for example, by a vent portion, and the free ends of the inductor sections have terminals for electrical connection to a current source.

[0052] In one embodiment, the first and / or second Joe provides one inverted T-shaped inductor element having parallel first, second, and third inductor sections interconnected in series, and the free ends of the inductor sections have terminals for electrical connection to a current source.

[0053] In one embodiment, at least one elongated inductor section has a thickness between 1.0 mm and 4.0 mm, for example, between 1.5 mm and 3.0 mm, when viewed perpendicular to Joe's front surface. The limited thickness of the inductor element enhances the cooling of Joe (including Joe's inductor). The reason is that, for example, one or more cooling fluid ducts are preferably arranged in the vicinity of the rear side of at least one inductor element.

[0054] In one embodiment, at least one elongated inductor section has a rectangular cross-section with a width greater than the thickness of the inductor section. This arrangement makes it possible to limit the thickness, which enables efficient cooling.

[0055] Each Joe may provide one or more cooling fluid ducts. For example, the cooling fluid is a cooling liquid (e.g., water), and, for example, using a pump assembly, the cooling fluid is passed through the cooling fluid ducts. For example, the cooling liquid circuit is a closed circuit including a heat exchanger, and the heat exchanger is configured to remove heat from the cooling liquid.

[0056] In certain embodiments, or in combination with cooling by a cooling liquid, air cooling may be used for the Joe. However, due to the volume, cooling by a cooling liquid is preferred. Preferably, the cooling liquid is passed very close to the Joe's inductor, for example, immediately behind one or more elongated inductor sections. Preferably, the cooling fluid is not passed into the region between the inductor and the susceptor element. The reason is that it would unduly increase the distance between them and also impair the effectiveness of the impulse heating induced by the field. Considering that it is desirable for the susceptor element to be very close to the front surface of the Joe, it will actually be recognized that there is no space for any cooling duct in said region. Thus, in a practical embodiment, the cooling of the Joe is preferably effected using a controlled flow of a cooling fluid (e.g., a liquid) through one or more ducts arranged behind (preferably very close to) the inductor sections.

[0057] In certain embodiments, at least one cooling fluid duct extends along at least one inductor section that extends along the rear side portion of the susceptor element.

[0058] For example, one or more cooling ducts are provided (e.g., machined) in the main body portion.

[0059] The main body portion can be 3D printed if desired.

[0060] In an embodiment, one or both jaws have a main body portion, for example, of a plastic material or a ceramic material (e.g., a heat-resistant material) (e.g., of PEEK), with a susceptor element and / or an inductor mounted on the main body portion. The plastic material or the ceramic material is selected so as not to impair the field generated by the inductor, at least not in an undesirable manner. Boron nitride and / or aluminum nitride, polyphenylene sulfide, a vulcanized silicone material can similarly be considered with respect to the main body portion. In particular, boron nitride provides thermal conductivity, thereby enabling good thermal conductivity from the susceptor element and the inductor towards the cooling device (e.g., towards the cooling fluid circulated through the jaw).

[0061] It is preferred that the machine is configured such that cooling of the jaw becomes active during the entire impulse sealing cycle and thus also generally during the generation of heat impulses that occur fast enough not to be impaired by cooling. In another configuration, the cooling can be interrupted or reduced around the instant of the heat impulse.

[0062] Cooling of the jaw can preferably be configured to cause cooling of the heat-sealed bottom region before the jaw is opened. For example, the film material is cooled to less than 60 °C, for example less than 40 °C, before opening.

[0063] In an embodiment, the susceptor element is made of a metal material, for example, a metal or a metal alloy, for example, made of a thin metal strip.

[0064] For example, the susceptor element is made of or comprises aluminum, nickel, silver, stainless steel, molybdenum, and / or nickel-chrome.

[0065] In certain embodiments, the susceptor element is embodied as an inverted T-shaped plate having opposing front and rear major surfaces that define the thickness of the plate therebetween. In certain embodiments, the thickness of the susceptor element plate is uniform over the extent of the plate.

[0066] In certain embodiments, the susceptor element includes a paramagnetic material, a diamagnetic material, or a ferromagnetic material. Such magnetic materials can be realized by an electromagnetic field and are adapted to realize eddy currents that cause the rapid heating described above in the impulse sealing technique.

[0067] In certain embodiments, each of the elongated susceptor parts is shaped as a strip, for example, a metal strip, such as an aluminum strip.

[0068] In certain embodiments, Joe is provided with a single continuous susceptor element embodied as an inverted T-shaped plate (for example, of metal).

[0069] In certain embodiments, the susceptor element (for example, embodied as a plate) has a thickness between 0.01 mm and 5 mm, preferably between 0.05 mm and 2 mm, more preferably between 0.08 mm and 0.8 mm, for example, between 0.08 mm and 0.5 mm.

[0070] In embodiments, the thickness of the susceptor element may locally differ from the nominal thickness. For example, the susceptor element includes a thickened portion at its rear surface (for example, facing away from the front surface of Joe), which can locally increase the strength of the electromagnetic field in the susceptor element and is adapted to locally increase the strength of the heat impulse emitted by the susceptor element.

[0071] Generally, considering the desire to rapidly cool the jaw including the inductor and susceptor after the end of the thermal impulse, it is considered desirable to have a minimum thickness of the susceptor element. The thin design of the susceptor contributes to this desire. In contrast to the impulse sealing device described in the introduction, it is noted that the current from the current source cannot pass through the susceptor, and thus the cross-section need not be designed to cope with such current flow.

[0072] Moreover, the minimum thickness of the susceptor element is preferred for sealing the pouch at the triple point in the side seal.

[0073] At the triple point, a discontinuous transition exists within the thickness of the pouch. At least in the area of the triple point to be sealed, having a thin susceptor element in combination with an elastically compressible material behind the susceptor element between the inductor and the susceptor element provides the advantage that the susceptor element can be temporarily deformed (and deformed during operation) when the first jaw and the second jaw are brought to their clamping positions. In this specification, the deformation is small. The reason is that it only acts to adapt the susceptor element to the thickness transition of the pouch wall at the triple point and is designed to provide a uniformly distributed heat transfer from the susceptor element to the pouch at the triple point. For example, the elastically compressible material is rubber (e.g., silicone rubber) or a polymeric material (e.g., Teflon®).

[0074] In one embodiment, Joe provides a single continuous susceptor element, which is embodied as an inverted T-shaped plate with three elongated susceptor parts. The three elongated susceptor parts are shaped as (e.g., metallic) strips having a thickness between 0.08 mm and 0.8 mm, for example, between 0.08 mm and 0.5 mm. For example, the strip is made of an aluminum material.

[0075] In an embodiment, the frequency of the current supplied to the inductor is between 100 kHz and 1 MHz, for example, between 250 KHz and 750 KHz.

[0076] In an embodiment, the magnitude of the current supplied to the inductor is between 20 A and 600 A.

[0077] In an embodiment, the current is supplied to the inductor at a voltage having a magnitude between 40 V and 500 V.

[0078] In one embodiment, Joe is embodied such that the high-frequency electromagnetic field generated by the inductor causes a very rapid development of heat in the front skin layer of the susceptor element, mainly due to the so-called skin effect. The skin effect is the tendency for alternating current to be distributed in a conductor such that the current density is maximum near the surface of the conductor and decreases exponentially as the depth of the conductor increases. At high frequencies, the skin depth becomes smaller. This depth can be, for example, 0.15 mm for an aluminum susceptor element when the frequency of the field is 350 KHz. The thickness of the susceptor element is assumed to be greater than this skin depth but not too large for the reasons stated herein.

[0079] In one embodiment, the distance between the rear surface of the susceptor element and the adjacent inductor section is at a minimum of 0.025 mm, or 0.05 mm, or 0.1 mm, and at a maximum of 3.0 mm, or 2.0 mm, or 1.0 mm. The minimum value of this distance is mainly assumed to enable effective electrical insulation between the inductor section on one hand and the susceptor element on the other hand. In an embodiment, it is assumed that this distance is filled only with an electrical insulating material. The maximum value of this distance is mainly assumed to have the inductor section very close to the rear surface of the susceptor element, and a maximum of 1.0 mm is preferred. In a practical embodiment, this distance can be 0.05 mm. Therefore, this distance can be smaller than the thickness of the susceptor element itself in a practical embodiment.

[0080] Preferably, the entire distance between the rear surface of the susceptor element and the adjacent inductor section is filled with an electrical insulating material.

[0081] In one embodiment, the distance between the rear surface of the susceptor element and the adjacent inductor section is filled by one or more layers of an electrical insulating material (e.g., tape), for example, at least a layer of Kapton tape and a layer of Teflon (registered trademark) tape, for example, filled by only one layer of Kapton tape and only one layer of Teflon (registered trademark) tape respectively.

[0082] In one embodiment, the electrical insulation between the rear surface of the susceptor element and the adjacent inductor section has a thickness of at least 0.025 mm, or 0.050 mm, or 0.1 mm, and at most 3.0 mm, or 2.0 mm at most.

[0083] In an embodiment, particularly in an embodiment where the susceptor element is small compared to the thickness of the inductor, the gap between the rear side portion of the susceptor element and the adjacent inductor section is filled by an elastic material, for example, an elastically deformable material such as silicone rubber or Teflon®. Particularly when a thin susceptor element is clamped against the triple point of the port (where a discontinuous transition exists within the thickness of the port), the elastic material may be able to deform according to the thin susceptor element. As is known in the art of port production, the triple point is a location where on one side of that point, there are two wall portions that will be joined, and on the other side of the triple point, there are two pairs of two wall portion segments (thus a total of four wall thicknesses) that will be joined. See, for example, WO2013 / 066328. The inductor is relatively thick and may not deform due to clamping. The elastic material can compensate for this difference in deformability between the inductor and the susceptor element, and can provide that the contact pressure is constant across the entire front surface of the susceptor element and that the susceptor element abuts evenly against the port wall. For example, in one embodiment, a silicone rubber layer or a Teflon® layer is provided behind the susceptor element. For example, the elastic layer has a thickness between 0.1 millimeter and 2.0 millimeters. It is understood herein that a thin susceptor element can bend to accommodate local variations in the number of walls.

[0084] In one embodiment, the anti - sticking layer on Joe's front surface is embodied as a layer of Teflon® tape. In another embodiment, the anti - sticking layer can include glass or the like.

[0085] In one embodiment, the front surface of the susceptor element is covered by a layer of Kapton tape having a thickness, for example, between 0.01 mm and 0.05 mm, for example, a thickness of about 0.025 mm.

[0086] In one embodiment, the distance between the front surface of Joe and the susceptor element is at a minimum of 0.025 mm, or 0.050 mm, and at a maximum of 2.0 mm, or 1.0 mm, or 0.5 mm. As used herein, the minimum distance may be governed by the presence of an anti - sticking layer. The anti - sticking layer may be coated on Joe, for example, on the susceptor element (for example, a glass or Teflon® coating).

[0087] In one embodiment, the distance between the front surface of Joe and the susceptor element is filled by a plurality of layers of electrical insulation tape, for example, at least a layer of Kapton tape and a layer of Teflon® tape as an anti - sticking layer forming the front surface of Joe, for example, filled by only one layer of Kapton tape and only one layer of Teflon® tape respectively.

[0088] In one embodiment, the front surface of Joe is smooth in the region of contact with the wall portion of the film material, and thus lacks any relief that would serve to locally separate and maintain the film material from the front surface, and thus lacks, for example, one or more ribs, bosses, etc. This arrangement is suitable in combination with the smooth design of the film material to provide a region of smooth contact.

[0089] In one embodiment, Joe is configured (e.g., has appropriate dimensions) such that each portion (e.g., at least half of the bottom region) of two adjacent interconnected ports is sealed in one cycle by Joe's operation. This avoids the need for additional sealing action in these portions of the bottom region, which is particularly preferred during the sealing of the bottom gusset of an upright foldable port.

[0090] In one embodiment, the sealing device is configured to provide a thermal impulse by a susceptor element between at least 150°C and a maximum of 200°C, 300°C, 400°C, or 500°C measured on the susceptor. It is noted that due to the very short duration of the thermal impulse and the very dynamic temperature changes, directly measuring this temperature requires complex / expensive temperature measurement equipment. Based on the analysis of the input electrical energy and heat flow / loss, the realized temperature can be approximated.

[0091] In one embodiment, the thermal impulse duration is between 10 milliseconds and 1000 milliseconds, for example, between 20 milliseconds and 500 milliseconds, for example, between 75 milliseconds and 400 milliseconds.

[0092] In one embodiment, the cycle includes a clamp cooling phase immediately following the thermal impulse, during which Joe is maintained in the clamp position, and the clamp cooling phase can have a duration between 200 milliseconds and 800 milliseconds, for example, between 300 milliseconds and 600 milliseconds. In a practical embodiment, the clamp cooling phase can be longer than the thermal impulse. This is because cooling is slowed down by the heat insulation properties of the plastic material.

[0093] It is noted that the control of the temperature reached during impulse heating can be effected based on monitoring and controlling the power supply to the inductor and / or by monitoring and controlling the temperature and / or flow rate of the cooling fluid (e.g., water) circulated along each jaw.

[0094] In one embodiment, at least one temperature sensor is provided which is configured to sense the actual temperature of the jaw, e.g., the actual temperature of the front surface of the jaw, e.g., the actual temperature of or near the susceptor element of the jaw, e.g., the actual temperature of the main body portion, and the temperature sensor is link-connected to a control unit of the current supply source. As used herein, the control unit (e.g., computerized) is configured to adjust the current fed to the inductor based on the output of the temperature sensor. For example, the current supply source is adjusted with respect to preheating and / or impulse heating of the jaw. Alternatively or additionally, the control unit (e.g., computerized) is configured to adjust the temperature and / or flow rate of the cooling fluid circulated along each jaw based on the output of the temperature sensor. For example, the cooling device is adjusted with respect to preheating and / or impulse heating of the jaw.

[0095] The control can be effected via a feedback type control mechanism such that the measurements during the first sealing cycle form the basis for controlling the current supply source and / or the cooling device and affect the impulse heating and / or cooling for subsequent sealing cycles.

[0096] In one embodiment, the sealing device (e.g., its control unit) is configured to effect preheating of the susceptor element before actual impulse heat sealing is performed. For example, the susceptor element is preheated to a preheating temperature between 50 degrees Celsius and 120 degrees Celsius, such as a preheating temperature between 60 degrees Celsius and 80 degrees Celsius, before a heat impulse is performed at a higher temperature of the susceptor element. The preheating can be done at the preheating temperature, which is preferably low enough to prevent the film material from being significantly affected. At the same time, the preheating reduces the temperature difference between the temperature of the susceptor before the heat impulse and the desired temperature of the susceptor during the heat impulse. The reduced temperature difference provides that the peak temperature can be reached in less time during the heat impulse and that the high-frequency electromagnetic field needs to be provided only for a shorter period of time. Thus, the time required for heat sealing is reduced, and it is possible to result in an improvement in productivity. Moreover, the shorter heat impulse time can serve to avoid the risk of damaging the film material.

[0097] In a further embodiment, the sealing device (e.g., its control unit) is configured to control the preheating of the susceptor element before the jaws are brought to the clamping position.

[0098] In one embodiment, the control unit can be configured to record one or more sealing parameters (such as one or more actual settings of a current supply and / or a cooling device, etc.) regarding the pouches being produced during the production of the pouches, so that it can later be retrieved which seal of which pouch was made with which specific settings. This can contribute to monitoring the quality of the seals within the pouches being produced.

[0099] The production machine is mainly envisaged for the production of pouches from a metal-free film material. For example, the film material of the wall part is a multilayer material, where materials that are all the same plastic but have different properties are found in all layers. In another embodiment, the wall part is a single-layer wall part. The absence of a metal layer enables more effective recycling.

[0100] In one embodiment, the film material (preferably a metal-free film material) comprises or consists of one or more layers each containing polyethylene (PE), such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE), and / or polypropylene (PP), and / or polyethylene terephthalate (PET). Thereby, the film material can include a mixture of two or more of these polymers, a laminate comprising one or more layers each composed of one or more polymers, or a single layer comprising a single one of these polymers. These polymers can have different properties, for example, from the perspective of mechanical strength and / or sealing capacity, and they can all be used to obtain a suitable material for the pouch.

[0101] In one embodiment, the film material is made entirely from polyethylene (PE), such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE), polypropylene (PP), or polyethylene terephthalate (PET). According to this embodiment, the film material is composed of a single type of polymer (e.g., a monomaterial), which can optionally enable the film material to be composed of a single polymer layer. The use of only a single polymer can improve the recyclability of the pouch. The reason is that it no longer requires separating various polymers. The reason is that the pouch wall contains only a single polymer. Also, there is no metal layer.

[0102] In one embodiment, the film material includes a layer of ethylene vinyl alcohol (EVOH) as an oxygen barrier, for example, for food packaging, instead of (and preferably without) a metal layer in the film. A film material with a single type of polymer as defined above can still contain a specific amount of EVOH (typically up to 5 wt%) while still being characterized as a monomaterial.

[0103] In an embodiment, a film material of a single polymer type can include multiple layers of the same polymer, however, it is noted that the layers can have differences in composition and / or properties, for example, due to the layers being oriented. Considering recycling, it is also possible to have a minimal amount of another polymer (e.g., an EVOH layer for barrier properties) in the pouch wall, for example, as an alternative to a metal layer in the film material.

[0104] In one embodiment, the film material is printed, for example, with surface printing provided on the side that is contacted by Joe of a sealing station having a susceptor and an inductor. Impulse sealing does not degrade the quality of the surface printing, as opposed to the use of a continuously heated seal joint. In an embodiment, the film material receives in-line surface printing of the film material, for example, immediately prior to sealing as disclosed herein.

[0105] In one embodiment, the production machine is embodied with a conveying mechanism configured to convey a string of interconnected pouches along a conveying path, and a sealing station as discussed herein is disposed along the conveying path. In one embodiment, the conveying mechanism is configured and operated to convey in an intermittent motion pattern (and thus stepwise). Often, a so-called walking beam conveying mechanism is used for the stepwise conveyance. Then, the sealing action is performed by the string of pouches at rest, and in a practical embodiment, the sealing station is fixedly mounted within the machine, at least with respect to the conveying direction.

[0106] In another preferred embodiment, the conveying mechanism is configured and operated to convey a string of interconnected pouches along the conveying path in a continuous motion, thus without stopping and starting, preferably at a constant speed. In this specification, the sealing station includes a motion device, and it is assumed that the motion device is operable to move a pair of jaws in synchronization with a continuously moving pouch or string of pouches during an impulse sealing cycle. The advantage of this approach is that unwanted deformation of the pouches is avoided (e.g., local stretching), which would otherwise result from rapid stops and starts. For example, the sealing station includes an endless motion device, and one or more (preferably multiple) sealing devices are moved along an endless path that extends along a portion of the conveying path. In another example, the motion device is embodied to reciprocate the sealing device in a direction parallel to the conveying path. In a continuous motion conveying variant, it is preferred that a cooling device is embodied such that a continuous circulation of coolant through one or more cooling ducts in the jaws can be established. In embodiments where the jaws are moved along an endless track, this can involve the use of one or more rotary couplings, for example connecting one or more hoses connected to the jaws to a stationary pumping and heat exchange system via one or more rotary couplings. In a reciprocating design, it may be sufficient to have one or more flexible cooling ducts between the jaws and the stationary pumping and heat exchange system on the one hand.

[0107] In one embodiment, the machine - a roll handling station adapted to receive one or more rolls of heat-sealable film material, and - One or more port-forming stations adapted and operative to form film material dispensed by a roll handling station into a series of pouches, e.g., into a string of interconnected pouches, each pouch optionally having at least one bottom gusset in its bottom region, which is formed by two folded bottom lobes below the triple point of the pouch. - For example, the port-forming station is embodied as a folding station, e.g., folding film material dispensed from a single roll into the shape of a pouch, the pouch including two port walls and optionally including a bottom gusset. - For example, the port-forming station is embodied as a cutting station, e.g., performing one or more cuts, e.g., partially, to shape and / or separate the pouch, a port-forming station. - For example, a sealing station as discussed herein. - A feeding mechanism adapted and operative to feed the formed pouches, e.g., as a string of interconnected pouches, to a sealing device, the device being locatable in one place at the same station. Includes one or more of the above.

[0108] The machine is preferably configured for the production of folded pouches, e.g., upright folded pouches with one or more gussets at the sides and / or bottom of the pouch.

[0109] In an embodiment, the machine includes a filling station configured to fill the pouches with product.

[0110] In one embodiment, the filling station is configured to fill the product into the pouch before sealing the spout to the pouch. The filling may then be carried out, for example, through the unjoined edge region at the top of the pouch, and the spout is sealed into the unjoined edge region at a later stage.

[0111] In one embodiment, after performing an impulse sealing cycle at the above-described station, for example, after sealing the bottom region of the pouch and after sealing the spout between the pouch walls, the pouch is filled on the production machine. For example, the filling is carried out, for example, in a sterile filling device through the spout, and optionally, a closing step follows, in which the spout is closed, for example, in a capping station provided with a capping device, and the capping device is configured and operated to place a cap on the spout.

[0112] In one embodiment, all the sealing devices of the production machine (including the sealing devices as discussed herein) are positioned at exactly the same station of the production machine. For example, the sealing device acts to continuously provide various seals without the film material being moved relative to the sealing device during the entire course of the various sealing steps. In one embodiment, all said sealing devices are arranged in one sterilized or aseptic chamber of the production machine.

[0113] The present invention also relates to a method for the production of a foldable pouch, preferably a foldable upright pouch including a bottom gusset, wherein a production machine as described herein is used.

[0114] Embodiments of the pouch production system and method will be described by way of example only with reference to the accompanying drawings, in which reference numerals indicate corresponding parts.

Brief Description of the Drawings

[0115]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Modes for Carrying Out the Invention

[0116] FIG. 1 schematically shows an embodiment of a production machine for the production of a foldable upright pouch, which is referred to by reference numeral 1. Also, the machine is also known as a form-fill-seal (FFS) machine and, in particular, in the embodiment shown, is known as a horizontal FFS machine.

[0117] The pouch production machine 1 is configured to produce a foldable pouch 2 (here, an upright foldable pouch) filled with a product. In the example shown, the upper edge is sealed over its length. In alternative embodiments, a plastics spout or other fitting is sealed into the upper edge.

[0118] The pouch 2 has opposing wall portions 3, 4 made from a metal-free heat-sealable film material 5 respectively.

[0119] The pouch production machine 1 has a frame (not shown) provided with a film supply device 6, and the film supply device 6 is adapted to receive one or more rolls 7 of a flexible heat-sealable film material 5. In the machine 1, the film material is unwound from the roll 7.

[0120] After unwinding, the film material 5 is guided towards a bottom gusset folding device 8, which folds the film material dispensed from a single roll into a folded shape such that the two pouch wall portions 3, 4 face each other and, as is well known in the art, the bottom has a gusset.

[0121] Until the moment of separation of the completed pouch 2, there exists a string of interconnected pouches being formed within the machine. In this embodiment, these pouches are filled while still interconnected in string form and then sealed. In another design, the pouches are separated from the string while still empty, for example, by a downstream filling station or at a remote location, for later filling.

[0122] In Figure 1, the individual pouches 2 within the string are shown separated by the dashed lines therebetween.

[0123] Each pouch 2 has a bottom gusset 9 with first and second gusset portions at its lower end.

[0124] Between the first pouch wall portion 3 and the second pouch wall portion 4, the first and second gusset portions are interconnected along the fold line 10.

[0125] At their respective side edges or vertical seams, the pouches 2 have a triple point 11 at the height of the fold line 10.

[0126] The machine 1 further includes a cutting station 12, which is configured to perform one or more cuts to shape and / or separate (e.g., partially) the pouches 2.

[0127] A feeding mechanism is provided, which is here formed by a set of traction rolls 13, and the feeding mechanism is adapted and operated to feed the string of interconnected pouches 2 so as to unwind roll 7 and along the sealing devices 15, 16 at the station.

[0128] Moreover, a filling station 14 is provided, which is configured to fill the product into the pouches 2.

[0129] The production machine 1 includes a sealing station, and the sealing station is configured to heat-seal the pouches. The sealing station includes a gusset sealing device 15 for sealing the bottom gusset regions 9 of two adjacent pouches 2 in a string of interconnected pouches 2 in a cycle. The bottom sealing device 15 is configured to heat-seal the pouches within the region of the gusset, for example, to create a heat seal between a first pouch wall portion and a first gusset portion immediately inside thereof, and to create a heat seal between a second pouch wall portion and a second gusset portion immediately inside thereof.

[0130] Along the transport direction (T), downstream of the gusset sealing device 15, the sealing station includes a side edge or side seam sealing device 16 for sealing the side edges of two adjacent pouches 2 in a string of interconnected pouches 2.

[0131] Further downstream, the sealing station includes a top edge sealing device 17 for sealing the top edge of the pouch 2 (here, after filling the pouch at the filling station 14 through the still open top edge).

[0132] In FIG. 1, a single jaw 18 of the gusset sealing device 15 is shown. This first jaw 18 faces towards the bottom gusset 9 on the first side wall portion 3. On the opposite side of the string of interconnected pouches 2, the gusset sealing device 15 includes a second jaw, and the second jaw faces towards the bottom gusset 9 on the second side wall portion 4.

[0133] The gusset sealing device 15 is provided with an actuator device 15a, and the actuator device 15a is configured to move the first jaw 18 and the second jaw relative to each other between an open position and a clamping position.

[0134] The gasket sealing device 15 further includes a cooling device, and the cooling device is configured to cool each of the first jaw 18 and the second jaw.

[0135] In FIG. 2, the sealing action of the machine 1 is schematically shown.

[0136] The first jaw 18 of the bottom sealing device 15 includes a susceptor element 19, and the susceptor element 19 has a front surface, and the front surface is shaped at least as an inverted T.

[0137] In FIG. 2, an exemplary contour of the susceptor element 19 is shown. The front surface of the susceptor element is positioned relative to the first port wall portion 3 at the clamping position. On the opposite side of the string of interconnected ports 2, a similar susceptor element of the second jaw is positioned relative to the second port wall portion 4.

[0138] During the operation of the machine 1 in the sealing cycle, like the configuration in FIG. 2, the susceptor element 19 partially protrudes over the bottom gasket region 9 of two adjacent interconnected ports 2.

[0139] The vertical centerline of the susceptor element 19 is thereby aligned with the separation line between the side edges of two adjacent ports 2. Thereby, the susceptor element 19 protrudes partway over the first port 2 by the first elongated susceptor part 20, and protrudes partway over the second port 2" by the second elongated susceptor part 21.

[0140] The susceptor element 19 further includes an upwardly oriented elongate susceptor part 22, which projects towards the upper end of the port 2 and projects at least over, and in particular over the lower part of, the side edges of two adjacent interconnected ports 2', 2". In operation, this upwardly elongate susceptor part 22 thereby at least partially seals the side edges of the adjacent interconnected ports.

[0141] The first elongate susceptor part 20 and the second elongate susceptor part 21, together with the upwardly oriented susceptor part 22, form a susceptor element 19 having an inverted T-shape. As shown by way of example, the three elongate susceptor parts 20, 21, 22 of the susceptor element 19 are shaped with a curvature between the respective laterally oriented susceptor parts and the upwardly oriented susceptor part, forming a rounded corner seal. By having an inverted T-shaped susceptor element 19, the gusset sealing device 15 simultaneously seals a part of the bottom gusset 9 of the first port 2' and a part of the bottom gusset 9 of the second port 2".

[0142] The susceptor element 19 further projects over the triple point 11 of the adjacent ports 2, which are positioned at the height of the fold line 10.

[0143] At this triple point 11, a heat seal is made by the first jaw 15 between the first port wall 3 and the first gusset part 3a immediately inside it, and a heat seal is also made by the second jaw between the second port wall 4 and the second gusset part 4a immediately inside it. Thus, at point 11, a discontinuous transition in the thickness of the port 2 occurs between the two upper layers and the four lower layers of the film material 5.

[0144] The gasket sealing device 15 further includes an inductor 24 within the first jaw 18 (not shown in FIGS. 1 and 2). The inductor 24 is electrically insulated from the susceptor element 19 and includes an elongated inductor section that extends along the respective front surfaces at the rear side portions of the susceptor element 19.

[0145] During operation, a current source is operated to temporarily feed a high-frequency alternating current to the inductor 24, thereby generating a high-frequency electromagnetic field by the inductor 24, and the high-frequency electromagnetic field induces alternating eddy currents in the susceptor element 19.

[0146] The eddy currents generate heat impulses that are dissipated by the susceptor element 19, and the heat impulses seal the bottom region of the port wall portion 3 to the adjacent gasket portion 3a. The same applies to the other jaw.

[0147] In FIGS. 3A and 3B, a cross-section of the first jaw 18 is shown, which is disposed in a clamped position relative to the first port wall portion 3. The first jaw 18 includes a main body portion 25 that provides one or more cooling fluid ducts. The cooling fluid is a cooling liquid (e.g., water, etc.) and is passed through the cooling fluid ducts, for example, by using a pump assembly. A cooling liquid circuit is provided, and the cooling liquid circuit is a closed circuit that includes a heat exchanger configured to remove heat from the cooling liquid.

[0148] The thickness of susceptor element 19 is small compared to the thickness of inductor 24. A gap exists between susceptor element 19 and inductor 24, which is filled by electrical insulator 26, which is adapted to prevent a short circuit between the two during operation of gasket sealing device 15. Insulator 26 is made of an elastic material, for example, an elastically deformable material (such as silicone rubber and / or Teflon®). The elastic material allows deformation of insulator 26 as thin susceptor element 19 deforms.

[0149] This deformation is particularly advantageous when thin susceptor element 19 is clamped against the triple point 11 of port 2, as shown in FIG. 4 (where a discontinuous transition exists within the thickness of port 2). Inductor 24 is relatively thick and will not deform at the clamping location, while thin susceptor element 19 will deform against the first port wall portion 3 at triple point 11. The elastic material of insulator 26 will compensate for this difference in deformability between inductor 24 and susceptor element 19, providing that the contact pressure is constant across the entire front surface of susceptor element 19 and that susceptor element 19 abuts uniformly against the first port wall portion 3.

[0150] In FIG. 5, an embodiment of susceptor element 19 and inductor 24 is shown. Susceptor element 19 is shown spaced from inductor 24 in order to illustrate the shape of inductor 24.

[0151] During operation of gasket sealing device 15, the front surface 27 of susceptor element 19 is very close to the wall of the port. Inductor 24 faces the opposing rear side of susceptor element 19.

[0152] The front surface of the susceptor element 19 has an inverted T-shape (i.e., a T-shape upside down).

[0153] The susceptor element 19 includes three elongated susceptor parts 20, 21, 22, which are interconnected at the central part 28 of the susceptor element 19.

[0154] In operation, the upwardly elongated susceptor part 22 protrudes towards the upper end of the port. The first elongated susceptor part 20 and the second elongated susceptor part 21 are aligned in opposite directions, and components that protrude laterally away from the upwardly elongated susceptor part 22 are, for example, in a state of being aligned laterally in the downward direction.

[0155] The susceptor element 19 is embodied in a continuous inverted T-shape with three elongated susceptor parts 20, 21, 22 each shaped as an elongated strip.

[0156] The inductor 24 includes a plurality of elongated inductor parts, for example, three elongated inductor parts connected in series at the central part of the inductor 24. Thereby, the first elongated inductor part 29 protrudes above the first elongated susceptor part 20. Thereby, the second elongated inductor part 30 protrudes above the second elongated susceptor part 21. Moreover, the third elongated inductor part 31 protrudes above the upwardly elongated susceptor part 22. Thus, the shape of the inductor 24 substantially corresponds to the shape of the susceptor element 19 and is adapted to provide a uniform distribution of eddy currents in the susceptor element 19 during the operation of the gasket sealing device 15.

[0157] The inductor 24 includes three groups (here, three pairs) of adjacent elongated inductor sections 32a, b, 33a, b, 34a, b.

[0158] The elongated inductor sections 32a, b of the first group (here, a pair) form the upwardly elongated inductor part 31.

[0159] The elongated inductor sections 33a, b of the second group (here, a pair) form the second elongated inductor part 30.

[0160] The elongated inductor sections 32a, b, 33a, b, 34a, b are arranged and extend in pairs parallel to each other and spaced from each other by the slit 35, thereby following the inverted T - shape of the susceptor element 19.

[0161] They are arranged close to the rear side portions of the susceptor element 19.

[0162] The slit 35 in the inverted T - shaped inductor 24 protrudes above the inverted T - shaped susceptor element 19 and is adapted to provide a homogeneous high - frequency electromagnetic field, thereby contributing to the homogeneity of the impulse heating of the susceptor element 19.

[0163] The elongated inductor sections 33a, b are connected via the bend 36. The elongated inductor sections 32a, b are connected via the bend 37. The inductor sections 34a, b have terminals for electrical connection to a current supply source. The bend 36, the bend 37, and the free end 38 protrude outside the contour of the susceptor element 19.

[0164] As shown in FIGS. 5 and 8, Joe is embodied such that the high-frequency electromagnetic field generated by the inductor part 33 causes a very rapid development of heat in the front skin layer of the susceptor element, mainly due to the so-called skin effect. The skin effect is the tendency for alternating current to be distributed in a conductor such that the current density is maximum near the surface of the conductor and decreases exponentially as the depth of the conductor increases. At high frequencies, the skin depth becomes smaller. This depth can be, for example, 0.15 mm for an aluminum susceptor element when the frequency of the field is 350 KHz. The thickness of the susceptor element is assumed to be greater than this skin depth but not too large for the reasons stated herein.

[0165] FIG. 9 shows an alternative embodiment of the inductor 24 embedded in the main body portion 25 of the first Joe 18. This inductor 24 is relatively wide compared to its height. The first elongated inductor part 29 and the second elongated inductor part 30 of the inverted T-shaped inductor 24 have lengths that are substantially greater than the length of the upwardly elongated inductor part 31. As such, this inductor 24 is particularly suitable for welding a pouch with a relatively low bottom gusset, the triple point of which is positioned at a relatively low part of the pouch.

[0166] In FIG. 10, a further alternative embodiment of the inductor 24 is shown, which is also embedded in the main body portion 25 of the first jaw 18. This inductor 24 includes a plurality of parallel inductor sections, which are separated from adjacent ones by slits respectively. A susceptor element 19 is disposed above the inductor 24. The susceptor element 19 has a front surface 27 having an inverted T shape, which includes three elongated susceptor parts 20, 21, 22, and the first elongated susceptor part 20 and the second elongated susceptor part 21 extend substantially laterally in opposite directions. The upwardly elongated susceptor part 22 extends upwardly and protrudes toward the upper end of the pouch to be sealed.

[0167] The susceptor element 19 includes a first intermediate susceptor part 20' between the first elongated susceptor part 20 and the upwardly elongated susceptor part 22, and is adapted to form a smoothly geometric transition between the first elongated susceptor part 20 and the upwardly elongated susceptor part 22. The susceptor element 19 includes a second intermediate susceptor part 21' between the second elongated susceptor part 21 and the upwardly elongated susceptor part 22, and is adapted to form a smoothly geometric transition between the second elongated susceptor part 21 and the upwardly elongated susceptor part 22.

[0168] FIG. 11 shows a further alternative embodiment of the inductor 24. This inductor 24 is relatively wide compared to its height. The first elongated inductor part 29 and the second elongated inductor part 30 of the inverted-T-shaped inductor 24 have a relatively smooth transition into the upward inductor part 31 of the inductor 24. In the upward inductor part 31, a relatively sharp first bend 36 is provided between the first elongated inductor section 32 and the second elongated inductor section 33, so as to optimize the geometry of the inductor 24 to achieve a substantially homogeneous high-frequency electromagnetic field during use.

[0169] In FIG. 12, another embodiment of the inductor 24 is shown. This inductor 24 is relatively wide compared to its height. The first elongated inductor part 29 and the second elongated inductor part 30 of the inverted-T-shaped inductor 24 have a length that is substantially smaller than the length of the upward elongated inductor part 31. As such, this inductor 24 is particularly suitable for welding relatively narrow ports compared to their height. Moreover, this embodiment of the inductor 24 enables, by means of the first elongated inductor part 29 and the second elongated inductor part 30 extending in a lateral direction on opposite sides, simultaneously sealing the bottom gussets of two adjacent interconnected ports and sealing the complete side edges of two adjacent interconnected ports from their bottom ends to their top ends over their entire height.

[0170] In FIG. 13, an embodiment of the first jaw 18 is shown in more detail. The first jaw 18 has an inductor 24 embedded in its main body portion 25. The jaw 18 has a cooling fluid duct provided in the main body portion 25. In the main body portion 25, the cooling liquid is passed very close to the inductor 24 (e.g., immediately behind it). The jaw 18 further includes a cooling fluid inlet port 39 and a cooling fluid outlet port 40 that project from the main body portion 25 and are configured to be connected to a cooling liquid circuit with a pump assembly and a heat exchanger, and the heat exchanger is configured to remove heat from the cooling liquid exiting the jaw 18.

[0171] In FIG. 14, an embodiment of a production machine is shown, which includes a sealing station as discussed herein and provides a motion device. Herein, the motion device is configured to move the first and second jaws 210, 220 in synchronization with a string of pouches that move continuously during an impulse sealing cycle. The operation is schematically shown by steps (a) - (e).

[0172] In the embodiment shown, the sealing device 200 includes a first jaw 210 and a second jaw 220. During the production of the pouches, a string of interconnected pouches that will be formed, having first and second wall portions 101, 102, is preferably continuously moved at a constant speed in the transport direction (T) from left to right in FIG. 14.

[0173] The motion device of the sealing station device 200 is configured to move the jaws 210, 220 in the transport direction (T) together with the pouch wall portions 101, 102, at least during the sealing cycle.

[0174] The cycle is initiated by step (a) (shown on the left side of FIG. 14). The first jaw 210 and the second jaw 220 are initially positioned spaced apart from the bottom regions of the port walls 101, 102.

[0175] During the operation of the first actuator device 201, the first jaw 210 is moved towards its clamping position and the first jaw 210 comes into contact with the first port wall 101 as discussed herein. Similarly, the second jaw 220 is moved towards its clamping position by the second actuator device 202 and the second jaw 220 comes into contact with the second port wall 102 as discussed herein. At their respective clamping positions, the first port wall 101 and the second port wall 102 are lightly clamped on top of each other in the region of the seal that will be formed. Since no significant pressure is involved in the sealing process, the clamping is light.

[0176] Next, during step (b), the jaws 210, 220 remain at their respective clamping positions and move with a string of interconnected ports that are continuously advanced. Step (b) is an impulse sealing step and during the impulse sealing step, an electromagnetic field is generated by the first inductor 211 and / or within the second inductor 221 to induce respective thermal impulses within the first susceptor 212 and / or the second susceptor 222.

[0177] Under the influence of the thermal impulses, the first port wall 101 and the second port wall 102 are locally fused in their bottom regions. For example, when no bottom gasket is present, they are fused directly to each other. Or when bottom gasket type ports are produced, they are fused on top of adjacent gasket portions.

[0178] During step (c), since one or more inductors are no longer excited, one or more thermal impulses are no longer provided, but the jaws 210, 220 remain in their clamped positions. Cooling fluid is circulated through ducts in one or more of the jaws 210, 220. Preferably, the supply of this cooling fluid is continued during all steps (a) to (e) of the sealing cycle. Thus, heat is also removed from the welded zone of the port 100.

[0179] During step (d), the first jaw 210 and the second jaw 220 are moved to an open position so as to move away from each other. When they are moved away from each other, the jaws 210, 220 are again spaced apart from each other.

[0180] Finally, during step (e), the first jaw 210 and the second jaw 220 are moved back towards their original positions. This movement can be made in a direction opposite to the transport direction (T) and is designed to result in the jaws 210, 220 being arranged in their original positions as at the start of step (a).

[0181] After moving the jaws 210, 220 back during step (e), the cycle is repeated and starts again with step (a).

[0182] It will be appreciated that the paths of the jaws 210, 220 can be of any suitable shape (e.g., circular, elliptical, linear, etc.).

Description of reference numerals

[0183] 1 Port production machine 2 Ports 2' First port 2" Second port 3 First port wall 3a First gasket portion 4 Second port wall 4a Second gusset portion 5 Film material 6 Film supply device 7 Roll 8 Bottom gusset folding device 9 Bottom gusset 10 Folding line 11 Triple point 12 Cutting station 13 Traction roll 14 Filling station 15 Gusset sealing device, bottom sealing device 15a Actuator device 16 Side seam sealing device 17 Upper edge sealing device 18 First joe 19 Susceptor element 20 First elongated susceptor part 20' First intermediate susceptor part 21 Second elongated susceptor part 21' Second intermediate susceptor part 22 Upward elongated susceptor part 24 Inductor 25 Main body part 26 Electrical insulator 27 Front surface 28 Central part 29 First elongated inductor part 30 Second elongated inductor part 31 Third elongated inductor part 32 First elongated inductor section 32a, b Elongated inductor section 33 Second elongated inductor section 33a, b Elongated inductor section 34a, b Inductor section 35 Slit 36 Bend 37 Bend 38 Free end 39 Cooling fluid inlet port 40 Cooling fluid outlet port 100 Port 101 First port wall portion 102 Second port wall portion 200 Sealing device, sealing station device 201 First actuator device 202 Second actuator device 210 First jaw 211 First inductor 212 First susceptor 220 Second jaw 221 Second inductor 222 Second susceptor T Transport direction

Claims

1. A production machine (1) for the production of folding pouches (2, 100), said pouches each having wall parts (3, 4, 101, 102) made of a heat-sealable film material, said production machine including a sealing station, said sealing station being configured to heat-seal the bottom regions (9) of two adjacent pouches in a string of interconnected pouches made of a heat-sealable film material, Said sealing station is - an impulse sealing device (15, 16, 200) including a first jaw (18, 210) and a second jaw (220), - an actuator device (201) configured to move said first jaw and said second jaw relative to each other between an open position and a clamping position, - a cooling device (20) configured to cool at least one of said first jaw and said second jaw and includes Said first jaw has a first front surface, said first front surface being configured to contact the bottom regions of the respective first wall parts of two adjacent pouches, Said second jaw has a second front surface, said second front surface being configured to contact the bottom regions of the respective second wall parts of said two adjacent pouches, At least one of said first jaw and said second jaw includes at least one impulse-heatable member at its respective said front surface, said impulse-heatable member extending along said front surface, said impulse-heatable member being covered by a heat-resistant anti-burn coating, Said production machine is configured such that, during operation, said string of interconnected pouches is positioned between said first jaw and said second jaw, and said impulse-heatable member is configured to at least partially protrude respectively over the bottom regions of two adjacent interconnected pouches, The sealing station is configured to perform an impulse sealing cycle, the actuator device is configured to bring the first jaw and the second jaw to the clamping position, and in the bottom region, the first wall portion and the second wall portion are clamped to each other by the front surfaces of the first jaw and the second jaw. The sealing station is configured to temporarily excite one or more of the impulse heatable members at the clamping position, generating an impulse of heat released by each of the impulse heatable members. After the excitation ends, the first jaw, the second jaw, and at least one or more of the impulse heatable members are cooled, and the cooling of the first jaw, the second jaw, and at least one or more of the impulse heatable members is assisted by the operation of the cooling device. The actuator device is configured to move the first jaw and the second jaw to the open position after at least one or more of the impulse heatable members are cooled. Each of the impulse heatable members is a susceptor element (19) containing a conductive material, and the susceptor element has a rear side portion facing away from each of the front surfaces. Each of the susceptor elements has a front surface shaped at least as an inverted T, and the impulse of heat is configured to seal at least a portion of the side edge region of the two adjacent interconnected ports and at least a portion of the bottom edge region of the two adjacent interconnected ports. At least one of the first jaw and the second jaw includes an inductor (24), the inductor is electrically insulated from each of the susceptor elements, the inductor includes elongated inductor sections (32a, 32b, 33a, 33b, 34a, 34b), and the elongated inductor sections extend along each of the front surfaces at the rear side portions of at least one of the susceptor elements. The sealing station includes a high-frequency current source, and the high-frequency current source is connected to the inductor among each of the first jaw and the second jaw that includes the inductor. In the impulse sealing cycle, the sealing station is operated such that the current source temporarily feeds a high-frequency current to one or more of the inductors, thereby generating a high-frequency electromagnetic field by one or more of the inductors. The high-frequency electromagnetic field induces eddy currents in each of the susceptor elements, generates heat impulses released by the susceptor elements, and one or more heat impulses seal the bottom region of the pouch, which is a production machine.

2. The production machine is configured to provide a string of interconnected pouches with bottom gaskets to the sealing station, and the first wall portion, the second wall portion, and the bottom gasket portion of two adjacent interconnected pouches are clamped to each other by the front surfaces of the first jaw and the second jaw at their clamping positions. Each of the first jaw and the second jaw includes a susceptor element and an inductor. The production machine according to claim 1.

3. Each of the susceptor elements includes three elongated susceptor parts (20, 21, 22). The production machine according to claim 1 or 2.

4. The inductor of the jaw includes a plurality of elongated inductor parts (29, 30, 31) interconnected at the central portion of the inductor. The production machine according to any one of claims 1 to 3.

5. The inductor of Joe includes a plurality of elongated inductor sections, the elongated inductor sections extend parallel to each other, and the elongated inductor sections are spaced from each other by slits (35). The production machine according to any one of claims 1 to 4.

6. The inductor includes three elongated inductor parts. The production machine according to claim 4 or 5.

7. The machine is configured such that the cooling of Joe is active throughout the impulse sealing cycle. The production machine according to any one of claims 1 to 6.

8. The susceptor element is made of a metallic material. The production machine according to any one of claims 1 to 7.

9. Each Joe is provided with a single continuous susceptor element embodied as an inverted T-shaped body portion with three elongated susceptor parts shaped as strips. The production machine according to any one of claims 1 to 8.

10. The thickness of the susceptor element is smaller compared to the thickness of the inductor, and the space between the rear side portion of the susceptor element and the adjacent inductor section is filled with an elastic material. The production machine according to any one of claims 1 to 9.

11. The production machine includes a conveying mechanism, the conveying mechanism is configured to convey the string of interconnected pouches along a conveying path in a continuous motion, the path extends at least along the sealing station, the sealing station includes a motion device, and the motion device is configured to move the first Joe and the second Joe in synchronization with the string of pouches that continuously move during the impulse sealing cycle. The production machine according to any one of claims 1 to 10.

12. The production machine is - a roll handling station adapted to receive one or more rolls of heat-sealable film material, - One or more pouch forming stations adapted and operative to form the film material dispensed by the roll handling station into a series of pouches, each pouch optionally having at least one bottom gusset in its bottom region, which is formed by two folded bottom lobes below the triple point of the pouch, - A feed mechanism (13) adapted and operative to feed the formed pouches to the sealing device, and The production machine according to any one of claims 1 to 11, further comprising one or more of the above.

13. The production machine according to claim 12, further comprising a filling station (14), the filling station being configured to fill the pouches with a product.

14. A method for the production of foldable pouches, the method using a production machine according to any one of claims 1 to 13.

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