RU2811932C2 - Pulse heat sealing of continuously moving film material - Google Patents

Abstract

FIELD: heat sealing.

SUBSTANCE: invention relates to heat sealing of heat sealable film material. A sealing system has been proposed for heat sealing superimposed walls of heat sealable film material, for example, in the manufacture of bags. The sealing system comprises two or more sealing stations arranged in series along a straight path for superimposed walls protruding from the loading section. Each sealing station includes a sealing device with the first and the second jaws and a drive device for causing the jaws to move between an opening position and a clamping position. Each sealing device includes a movement device configured to cause the first and the second jaws to move synchronously with the superimposed walls when they are clamped between the first and the second jaws. Each sealing station has a cooling device configured to continuously cool at least one of the jaws. At least each first jaw contains, next to its corresponding front surface, at least one pulse-heated element, configured as a current-receiving element, which extends along the corresponding front surface. Each sealing station is designed to perform an integrated pulse sealing and cooling cycle.

EFFECT: group of inventions improves the quality of the products obtained.

19 cl, 21 dwg

Description

The present invention relates to heat sealing of heat sealable film material. For example, the invention provides for the manufacture of bags, for example bags having a fitment and having walls made of heat-sealable film material.

For example, in the manufacture of pouches, superimposed walls of heat-sealable film material are welded to each other and to a fixture, if any, by means of a welding system that comprises a plurality of sealing stations arranged in series to sequentially create a plurality of sealed zones for each pouch, e.g. , along the top, sides and/or bottom of the package.

An example of such a welding system is disclosed in document EP 999 130 A1, which discloses a welding system according to the preamble of claim 1. This known sealing system is configured to receive two rolls of heat sealable film material at a roll handling station in which the rolls are unwound, after which two walls of heat sealable film material are brought closer to each other so that they are superimposed on each other. The superimposed walls are moved through the welding section along a straight path at a constant speed, for example, so that they are not periodically tensioned, by means of a station for setting the film material in motion. Continuous movement of the walls prevents or at least reduces local stretching of the film material compared to periodic, intermittent movement of the film material through the sealing section. This driving station, located downstream of the welding section, has, for example, two rollers between which the walls are clamped and a corresponding drive motor.

EP 999 130 A1 provides that, as is customary in the art, the jaws of each of the welding stations are continuously heated, for example electrically, to a temperature that is suitable for heat sealing. This is known as heated plate/knife welding technology. During operation, the continuously heated jaws move into a clamping position in which walls of heat-sealable film material are clamped between them. The jaws in the clamping position are then moved synchronously with the superimposed walls for the time required to form the heat seal weld. The heated jaws are then moved to the opening position and back to the original position for the next heat sealing cycle. The welding section in a known welding system further comprises a downstream cooling station for cooling the welds that have been formed by the welding stations.

It is desirable to make the bags from metal-free, heat-sealable film materials, preferably single-polymer heat-sealable film materials, also called mono-material plastic films, which allow for efficient recycling. Such film materials typically contain only one or more polymeric materials, for example, only one polymeric material, for example, one or more layers of one or more of polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). In embodiments, the film material may have a non-metallic barrier layer, such as one designed for oxygen permeability, such as an ethylene vinyl alcohol (EVOH) barrier layer. Such a layer is often not considered to have a negative impact on recyclability. Due to the absence of a layer of metallic material in the film material, these metal-free, heat-sealable films are generally less strong and more brittle than conventional film material that contains a metal layer. This film can be described in general terms as having relatively low tensile strength and relatively high elasticity, particularly when the film is heated locally during the heat sealing process. In particular, at elevated heat sealing temperatures, the strength of the metal-free film material is significantly reduced, at least temporarily, resulting in local deformation when heat sealing is performed in the known manner.

The known welding system according to EP 999 130 A1 is suitable for the production of bags having walls made of film material including a metal layer. This known system is considered unsatisfactory for the manufacture of bags having walls formed from a metal-free, heat-sealable film material, for example, a single polymer film material. This is mainly due to the above mentioned effects. In heated plate welding stations, continuously heated jaws contact the film material walls in a clamping position so that a weld is formed. This contact must be discontinued as soon as the weld has been completely formed to prevent overheating, such as localized melting of the walls. However, when the jaws are moved to their opening position, the walls - which in this case are soft because they are still warm - are again subjected to the pulling force exerted by the driving station, and the heat-sealed area is not supported on the lips. This causes local stretching and deformation, noticeable, for example, in the form of damage to the film layer, wrinkles, deformation of the printed pattern on the film material, etc. This leads, for example, to the need to reduce the speed of the welding system in order to be able to use less pulling force, which is economically unfavorable. In addition, when continuously heated jaws are in their open position and positioned some distance from the walls, such as when they are moved back to their original position in a cycle, the heat emitted by the jaws tends to cause excessive softening of the film material walls.

The present invention is directed to an improved sealing system, for example, to overcome or reduce one or more of the above disadvantages, for example, in the manufacture of bags having walls of metal-free, heat-sealable film material, for example, a single-polymer heat-sealable film material.

In accordance with the invention, a welding system is provided according to claim 1 of the claims.

In this system, each pulse-heated element is made in the form of a current-receiving element containing electrically conductive material. In each of the welding stations, at least one of its jaws contains an inductor. The system contains a source of high-frequency electric current connected to an inductor. The inductor is preferably mounted in the same jaw as the current collector, for example the inductor extends along the rear side of the current collecting element.

Each welding station is configured such that, in an integrated pulse welding and cooling cycle, an electric current source temporarily supplies a high-frequency electric current to an inductor, whereby a high-frequency electromagnetic field is generated by the inductor, and the high-frequency electromagnetic field induces eddy currents in the current collector element, creating a thermal impulse emitted by the current-receiving element, wherein said thermal impulse ensures welding of a zone of walls superimposed on each other, or welding of walls to a device, if any. This design allows for a very efficient and controlled generation of a thermal pulse emitted by the current collector towards the area to be heat sealed.

Each of the welding stations contains a set of jaws that remain in the clamping position during the entire integrated pulse welding and cooling cycle, and not just during the actual heat sealing as in EP 999 130 A1. The cycle according to the invention includes heat sealing of a given zone, wherein said heat sealing is immediately followed by effective cooling of at least one of the jaws, for example both jaws and therefore also the welded zone, while the jaws remain in the clamping position after the thermal impulse.

The cooling device of each welding station carries out continuous cooling of at least one of the first and second jaws, for example both jaws, therefore even during the action of the thermal impulse, since its duration in practice is so short that interrupting the cooling during the action of the thermal impulse is impractical . In practical embodiments, the system may be configured and operated to cool the heat sealed area prior to jaw opening to a temperature below 60°C, for example below 40°C.

Thus, in contrast to the known welding system according to EP 999 130 A1, the proposed welding system ensures that the jaws are held in the clamping position both during the heat sealing pulse and during subsequent cooling. Therefore, the induction-based pulsed heat sealing explained herein and cooling occur using the same set of jaws. Unlike the known welding system, it is not necessary in practice for the welding section of the system to be provided with a cooling station, for example a cooling station in which the welded zone is sandwiched between two cooling elements, for example cold bars or cold plates, to cool the zone . The preferable absence of any additional, specially provided cooling station in the welding section of the system allows the length of the welding section to be reduced. This is advantageous for reasons related to the control of the pulling force acting on the walls superimposed on each other, as well as to reduce the area occupied by the system. In addition, the fact that in the system according to the invention, cooling begins virtually immediately after power supply to the inductor is interrupted avoids unwanted dissipation of heat to locations where heating is not desired and/or where later heat removal is difficult. For example, in a system according to EP 999 130 A1, heat dissipation from the welded zone occurs in the time interval between the end of the heat seal at the welding station and the start of cooling by a downstream, specially provided cooling station. For example, when heat sealing a fixture to walls, such as when making bags, heat will tend to dissipate away from the actual sealing zone between the film material wall and the fixture to other parts of the fixture, for example, further away from that welding zone. The approach according to the invention effectively counteracts this effect.

In practical embodiments, the front surface of the jaw, for example at least the jaw provided with the current collecting element, is coated with a non-adhesive coating. For example, the coating is Teflon tape or other tape that has anti-adhesive properties, allowing, for example, replacement of the coating when it becomes worn or becomes dirty during long-term heat sealing operations. The coating may also be formed integrally with the current collecting element, for example, in the form of a layer on the current collecting element integral with it, for example a layer of glass. The non-adhesive coating on the front side of the jaw is preferably the only component separating the current collector element from the film material to be welded.

The welding system according to the invention makes it possible to weld a metal-free, heat-sealable film material, for example a heat-sealable film material from a single polymer, by heat sealing to the same material and to a fixture, if any, for example in the manufacture of bags, for example, to the pouring element of a bag with pouring element. For example, the film material is a single polymer heat sealable film material formed from polyethylene (PE), such as low density polyethylene (LDPE), or polypropylene (PP), or polyethylene terephthalate (PET), or a multi-polymer heat sealable film material formed from combinations of these polymers. As discussed, any metal layer is preferably absent from the film material. As discussed, it is possible that the film material contains a non-metallic polymer layer that is not permeable to oxygen, such as an ethylene vinyl alcohol (EVOH) polymer. Alternatively, the proposed system also provides the ability to heat seal a film material that contains a metal layer, such as an aluminum layer, for example, an aluminum layer between layers of polymers such as polyethylene (PE) and/or polyethylene terephthalate (PET). It should be noted that the sealing system according to the invention also allows for heat sealing of a heat sealable film having a metal layer.

In the prior art, in order to economically perform heat sealing in practice, it was necessary to have a metal layer in the film material to provide sufficient resistance to the combination of thermal and mechanical stresses to which the film walls are subjected as they pass through the sealing section. As explained herein, the approach of the invention avoids such conditions. For example, it provides the ability to weld metal-free, film materials formed from a single polymer and having a limited thickness, for example in the manufacture of bags. Such materials are more recyclable and require less plastic, making them more environmentally friendly and less expensive.

An advantage of the welding system according to the invention is that the modes/conditions allow the use of relatively thin walls of film material, for example metal-free film material. The limited wall thickness provides increased efficiency, for example, the rate of transfer of the thermal impulse from the jaw having the current-receiving element to the area in which the weld is to be created. For example, in the manufacture of bags having a device welded between opposite walls, for example, a pouring element, for example, in the edge zone of the bag, a device welding station is used, in which each of the jaws has a current-receiving element. In this case, the thermal impulse is transmitted with high efficiency from the current-receiving element in each jaw to the nearest welding zone between the film wall and the attached part of the device. Because of this, in embodiments, the temperature that is reached in the current collector during the heat sealing pulse can be kept relatively low compared to the temperature required in existing heated plate/blade welding systems.

The difference between the temperature of the current collecting element when energy is supplied to it by a high-frequency field and the heat sealing temperature, which is the melting point of the heat sealing film material and/or device, may be referred to as delta-T or delta temperature. When using the welding system according to the invention, preferably in the case where the heat sealing is based on the use of a current collector in a sponge heated by a high frequency field generated by an inductor as described herein, the delta-T in practice can be small compared to existing heated plate welding systems /knives. Accordingly, the likelihood of overheating of the film material in direct contact with the front surface of the jaw is reduced, resulting in less or no damage to the film material and improved weld quality. In addition, low delta-T may provide the ability to weld film materials that in the past could not be effectively heat sealed, for example, may provide the ability to weld a wall of metal-free polypropylene (PP) film material to the attachment portion of a polypropylene (PP) fixture , for example, the pouring element of the package.

Since there is no requirement for one or more dedicated cooling stations along the welding section, for example located downstream of the welding stations, the welding system according to the invention can be substantially smaller in size, for example having a length along the welding path that is at least 50% less compared to prior art welding systems, for example in the production of bags. This reduces the required space in an industrial plant, eg a plant in which the substance to be filled in the bags is produced, either requiring a smaller plant or allowing more equipment to be installed in the same plant. For example, the reduced footprint of the sealing system of the invention may allow for more convenient integration with a filling device for filling bags with substance. In addition, the preferred absence of one or more dedicated cooling stations in the welding section may provide a less complex and therefore more reliable welding system.

In many embodiments, the immediate cooling effected in the system of the invention may, for example, depending on the polymer(s) in the film material and/or fixture if present, provide improved crystallization in the welded zone, wherein said improved crystallization may result in to increased quality of the weld obtained by heat welding.

Moreover, in practice, welding stations may be configured and operated such that only a minimum clamping force is provided by the jaws in the clamping position, e.g. less, e.g. significantly less, than in the case of traditional, continuously heated welding stations. jaws, with the clamping force being the main parameter of the welding process. For example, the drive device comprises a stepper drive for the jaws, for example with position control. In an embodiment, an elastic element, for example one or more springs, is/are located between the stepper drive and the jaws such that the position of the stepper drive corresponds to the clamping force generated by the jaws.

The clamping force can be effectively limited to such a level that it only serves to ensure close contact between the wall surfaces in the area to be heat sealed, for example to avoid the presence of air between the areas to be welded. This is particularly advantageous in combination with induction heating of the current collector in at least one of the welding station jaws, as described herein. Thanks to the lower clamping forces which advantageously operate in the cycle according to the invention, any risk of damage to the film material is significantly reduced. This may make it possible to reduce the thickness of the film material, in particular the metal-free film material, resulting in less plastic being required to make a bag, for example.

The movement device provided at each welding station may be configured to provide reciprocating movement, hence moving the jaws back and forth along a straight path. In this case, the jaws stop at the end of the stroke and move in the opposite direction. Together with the substantially lateral movements to clamp and open the jaws, this can result in a so-called rectangular jaw path. Alternatively, the movement device may cause each jaw to move continuously in one direction along a closed path, such as an ellipsoid. Typically, the jaws move with the superimposed walls in a clamping state and then move away from the walls and then move back in the opposite direction away from the superimposed walls to the original position.

In practical embodiments of the system, even though heating and cooling occur during one stroke of the jaw set, the length of the stroke along a straight path is relatively short.

In practice, the welding system may operate at a high speed, for example defined in packets per minute, for example taking into account the speed at which the superimposed walls move under the action of the pulling force. It should be noted that since each of the welding stations is independently controlled, it is possible to provide a heat pulse for each weld to be formed with a duration that is independent of the overall cycle time. After emitting a heat pulse, the welded zone is immediately cooled for the remaining time while the jaws are held in the clamping position. In practice, no problem arises if the jaws are held in the clamping position even longer than necessary to cool to a given degree, for example for reasons related to strength that must be restored, since prolonged clamping can only provide more cooling to the welded area, which does not causes harm and may even be beneficial for weld quality.

The sealing station jaws are cooled after the heat sealing pulse has expired, so that when the jaws are moved to the open position they are actually quite cold. This is preferable considering the general temperature/heating situation in the vicinity of the welding station. For example, there is no excessive heating of the film walls due to the heat generated by the open jaws moving back to their original position during movement. This negative effect of the heat generated by open jaws is observed in the heated plate/knife welding system according to EP 999 130 A1. Avoiding this excessive heating is also advantageous in embodiments in which the welding section is configured such that the welding stations are located in an aseptic chamber.

Due to the fact that the jaws are quite cold in their opening position, in an embodiment in which the jaws remain facing the stacked walls while they move back to their original position along a straight path, excessive heating of the stacked walls is avoided. friend. For example, the jaws extend along the top or bottom edge of vertically oriented stacked walls, passing through the welding section back to their original position where the jaws clamp the walls. However, this edge zone may become excessively heated in the case of welding with heated plates/knives and undergo unwanted stretching under the influence of pulling force. In addition, due to the fact that the jaws are quite cold in their opening position, the jaws do not necessarily have to be removed far from the walls to perform the reverse movement, thereby limiting the amount of distance between the jaws in the opening position, which facilitates high-speed operations . In the event of a shutdown of the welding system, the fact that the jaws are quite cold when open makes it possible to avoid excessive local heating of that very part of the walls located at the welding station when the system is stopped, for example due to a malfunction. This can provide an increase in the overall efficiency of the welding system compared to heated plate/knife welding systems.

In most cases, the welding system of the invention is capable of operating at a high release rate, that is, the high speed at which the walls of the heat sealable film material are pulled along a series of welding stations, resulting in increased productivity. Productivity can be up to three times higher compared to known welding systems, for example those made with continuously heated jaws and specially designed cooling stations. This occurs in particular in combination with induction heating of a current collector in one of the jaws of the welding station, as described herein. In addition, the welding system can operate with lower energy consumption because the jaws do not need to be heated continuously, but only for a short period of time during the heat pulse.

The control unit provided in the welding system is configured - independently for each of the welding stations - to regulate the thermal pulse emitted by the at least one current-receiving element, for example, to regulate the magnitude and/or duration of the thermal pulse, and is configured - independently for each of the welding stations - controlling the drive device to move the first and second jaws relative to each other between the opening position and the clamping position, which allows you to adjust the time the first and second jaws remain in the clamping position and, thereby, the duration of cooling in the clamping position. As explained herein, the cooling of at least one of the jaws of each welding station, preferably both jaws, is continuous such that cooling of the welded zone occurs as long as the jaws clamp the welded zone following the application of a thermal pulse.

In an embodiment, both walls to be joined are formed from a heat-sealable film material, preferably a metal-free heat-sealable film material, for example in the manufacture of soft bags or in the manufacture of packaging materials with air-filled pockets.

The sealing station may be configured to heat seal the walls of a bag, for example heat seal the walls of a Bag-in- Box , for example of the type disclosed in WO 2015/189036 A1.

In addition, the welding station may be configured to weld the pourer element to the wall of the bag by heat sealing, for example by heat sealing the annular attachment flange of the pourer element, for example, a pourer element in a Bag-in-Box package, for example of the type disclosed in WO 2015 /189036 A1.

In a preferred embodiment, the control unit, together with the one or more cooling devices, is configured to regulate the cooling rate of at least one of the first and second jaws, as well as the area that is welded by the welding station, independently for each of the welding stations. For example, the flow rate and/or temperature of the coolant fluid, such as water, which cools one or both jaws of one welding station, can be adjusted independently of the flow rate and/or temperature of the coolant fluid, such as water, which ) cools one or both jaws of the other welding station. For example, in practical embodiments, a liquid coolant, such as water, is supplied to the welding station jaw(s) at a temperature of 10 to 25° C. to cool the jaw(s). For example, the lower temperature limit of the coolant liquid supplied to the sponge(s) is selected to avoid condensation, for example, on flexible coolant lines connected to the sponge(s).

The advantageous ability to control each welding station independently of other welding stations during both pulsed heating and cooling increases the operational flexibility of the welding system, allowing, for example, the processing of a wide variety of film materials, such as metal-free film materials. It is also possible to expose the welded area to temperatures at a precise temperature profile during the cycle time of the invention, which promotes the formation of a reliable and repeatable weld that is heat sealed through each of the welding stations.

Control of pulsed heating and post-cooling is preferably provided through a system configuration that allows parameters associated with the independent operation of each welding station to be independently adjusted. Examples of such parameters when controlling the heat welding performed by the at least one welding station susceptor element are the magnitude of the heat pulse, the duration of the heat pulse, the amount of heat contained in the emitted heat pulse (for example, based on regulating the amount of energy supplied to the inductor), and Examples of such parameters in cooling control are the duration of effective cooling between clamped jaws, cooling rate, etc. Other parameters may include, for example, clamping force and/or total clamping duration, and/or jaw return speed.

In embodiments, the movement devices are configured to provide complete individual control of the movement of the jaws along a straight path with the given welding walls and back to the original position when the jaws are in the open position.

In pouch manufacturing, the ability to individually control the heat sealing and cooling processes discussed herein promotes flexibility in the welding system and allows many different types of pouches to be welded by the same welding system under different pulse heating, cooling, drive and/or support device parameters. movement, for example, in the absence of the need for complex mechanical modifications to the welding system when moving from one package to another. This makes it possible to reduce changeover/changeover times between the production of different types of products, for example bags, and therefore increases productivity to an even greater extent.

In addition, when starting a new welding system or when changing from one product to be manufactured by the system to another product to be manufactured, the current collector elements can achieve constant operating conditions, such as stable temperature characteristics of the jaws, faster than a welding system based on prior art, having continuously heated sponges. This allows for greater overall efficiency, such as less production waste and/or a reduction in the time required for the transition. In known welding stations with continuously heated jaws, it can take up to 30 minutes at start-up before a truly stable operation is achieved. Instead, according to the approach of the invention, it may take less time, typically only 1 to 2 minutes, for the welding station jaws to reach a stable state.

In embodiments, one or both jaws have a main body, such as a plastic or ceramic material, such as a heat-resistant material, such as polyetheretherketone (PEEK), on which the current collector element and/or inductor are mounted. For example, a current collector is installed on the surface of the main body. For example, the inductor is embedded in the main body, for example, placed in a through hole in the main body. The plastic or ceramic material of the main body of the jaw is selected so that it does not adversely affect the high frequency field generated by the inductor, or at least not in an undesirable manner. Boron nitride and/or aluminum nitride and/or polyphenylene sulfide and/or vulcanized silicone materials may also be considered as materials for the main body. In particular, boron nitride provides good thermal conductivity, thereby allowing good heat transfer from the current collecting element and inductor to a cooling device, for example, a cooling fluid, such as water, circulating through the channel(s) in the main body.

In an embodiment, the current collecting element is made of a metallic material, for example a metal or a metal alloy, for example, in the form of a thin metal strip. In an embodiment, the current collecting element, for example in the form of a strip, has a thickness of from 0.01 to 5 mm, preferably from 0.05 to 2 mm, more preferably from 0.08 to 0.8 mm, for example from 0. 3 to 0.5 mm. In most cases, it is considered desirable to have a minimum thickness of the current-collecting element, taking into account the desire to quickly cool the sponge, which includes, for example, an inductor and a current collector, after the end of the thermal pulse. The design of the pantograph with low thickness contributes to the realization of this ambition. It should be noted that no electrical current from the current source passes through the pantograph, so there is no need to design the cross-section to handle such current flow.

In an embodiment, the thickness of the current collector element at a particular location may differ from the nominal thickness. For example, the susceptor element may have a thick portion adjacent its rear surface, for example, facing away from the front surface of the jaw, to locally increase the electromagnetic field strength in the susceptor element to locally increase the magnitude of the thermal impulse emitted by the susceptor element.

The current collecting element is made, for example, of aluminum, nickel, silver, stainless steel, molybdenum and/or chromium-nickel alloy or contains aluminum, nickel, silver, stainless steel, molybdenum and/or chromium-nickel alloy.

In an embodiment, the current collecting element is configured as a strip having opposing front and rear main surfaces that limit the thickness of the strip between them.

In an embodiment, the thickness of the current collecting element is constant over the entire length of the element.

In an embodiment, the current collecting element is made in the form of a flat strip. In this case, the plane of the strip is preferably parallel to the front side of the sponge.

The front side of the jaw equipped with a current-receiving element, possibly both jaws equipped with a current-receiving element and an inductor interacting with it, is preferably smooth, therefore, does not have any relief that causes the wall of film material to be held in a certain place at a distance from the jaw and creating air pockets between the sponge and the wall of the film material. This smooth front design ensures very efficient transfer of the heat impulse from the jaw to the area where the joint is formed. In practice, it can be observed that the heat sealed connection is formed in the entire zone in which the current collector radiates heat towards the walls of the film material.

In an embodiment, each of the welding station jaws includes a current-receiving element of electrically conductive material, as well as an inductor interacting with it, and the welding station preferably has a plurality of electrical current sources, each of which is connected to a corresponding inductor of the corresponding jaw. The control unit is preferably configured to independently control each of the electrical current sources at the welding station to individually adjust the current supplied to each of the inductors to enable individual adjustment of the thermal pulse emitted by each jaw of one welding station. This, for example, makes it possible to change the timing of the thermal pulse emitted by the first jaw relative to the thermal pulse emitted by the second jaw, for example, one is supplied after the other or with some variation in timing, for example, taking into account the heat input to the welding zone.

In an embodiment, the susceptor element extends along the front surface of the corresponding jaw and has a rear side, wherein the susceptor element is configured, for example, in the form of an elongated strip or has one or more parts shaped like elongated strips, wherein each inductor includes an elongated inductor portion that extends along the rear side of the corresponding current collecting element, for example parallel to the current collecting element.

Due to the fact that the at least one elongated part of the inductor, for example, the straight part of the inductor, extends along the front surface of the jaw, as well as along the current collecting element, substantially parallel to the current collecting element, for example, in an embodiment, adjacent to the rear side of this at least one current-receiving element, preferably in the immediate vicinity of said rear side, the heat generation along the front side of the jaw occurs in an efficient manner, in particular quite uniformly. The elongation of a part of the inductor, made, for example, in the form of a strip, contributes to a uniform current density in this part of the inductor, for example, compared to a serpentine or other relatively irregular shape of the part of the inductor. This uniformity “transforms” into the uniformity of the high-frequency field and, thereby, into the uniformity of pulse heating of the current-receiving element. The circumstance indicated by the latter contributes to reliable and efficient heat sealing in the seam areas of walls made of film material.

The uniformity of the heat seal and pulse action allows for minimal clamping force to be generated by the jaws in the clamping position, for example significantly less force than with traditional, continuously heated welding jaws. The clamping force can actually only serve to guarantee tight contact between the surfaces of the walls or between the surfaces of the walls and the attached part of the device, if present, for example, in a bag with a pourer element.

In embodiments, the inductor is a solid cross-section inductor made of metal or other material, preferably with high conductivity, for example, preferably made of copper. This design avoids excessive variability in the current density in the inductor and thus unwanted changes in the generated field, for example, in contrast to an inductor that is hollow inside. In an alternative, less preferred embodiment, the inductor is a stranded high frequency winding wire. As a result of observations, it was found that in such an embodiment, heating of the high-frequency winding wire may become problematic and cooling is difficult.

In an embodiment, the jaw inductor includes a plurality of elongated inductor portions parallel to each other, for example, straight elongated inductor portions. In embodiments, these parts are located adjacent to each other in a plane that is parallel to the front surface of the jaw. Adjacent parts of the inductor are separated from each other by a gap, for example an air gap or a gap filled with electrical insulating material. In embodiments, the sponge inductor includes several, for example, only one pair of elongated inductor parts that are parallel to each other and separated from each other by a slot. In this case, the current-receiving element, as viewed from the front surface of the jaw, extends over the slot(s), for example, over a given single slot existing between two parts of the inductor. The presence of a gap between parallel parts of the inductor, for example, straight elongated parts of the inductor, allows the desired concentration of the field created by the sponge inductor in the current collector. In an embodiment, the current collecting element extends over a gap existing between the parallel portions of the inductor as viewed from a view of the front surface of the jaw.

In embodiments, the gap between adjacent inductor portions, eg, straight elongated inductor portions, has a width of from 0.01 to 5 mm, more preferably from 0.1 to 2 mm.

In an embodiment, the at least one elongated inductor portion, for example the straight elongated inductor portion, has a thickness of from 1.0 to 4.0 mm, for example from 1.5 to 3.0 mm, when viewed in a direction perpendicular to the front surface of the sponge. The limited thickness of the inductor element provides improved cooling of the sponge, including the conductive material of the sponge, since, for example, one or more cooling fluid channels are preferably located near the rear side of the at least one inductor element.

Supplying power to the inductor to perform heat sealing may consist of applying a high frequency electrical current through the inductor for a single, short period. It can also be performed in a sequence of even shorter periods, for example with different electric currents being passed through an inductor for different periods to perform a single heat sealing operation.

In embodiments, the frequency of the electric current supplied to the inductor is from 100 kHz to 1 MHz, for example, from 250 kHz to 750 kHz.

In embodiments, the amount of electrical current supplied to the inductor ranges from 20 A to 600 A.

In embodiments, electric current is supplied to the inductor at a voltage of between 40 V and 500 V.

In an embodiment, the duration of the thermal pulse is from 10 to 1000 milliseconds, for example from 20 to 500 milliseconds, for example from 75 to 400 milliseconds.

In an embodiment, the cooling time in the clamp position, or the effective cooling phase that immediately follows the thermal pulse, may have a duration of from 200 to 800 milliseconds, for example from 300 to 600 milliseconds.

The inductor is preferably mounted in the same jaw as the current collector, with the inductor extending, for example, along the rear side of the current collecting element. In another embodiment, the first jaw is provided with a current collecting element and the second jaw does not have a current collecting element, wherein the second jaw is provided with an inductor and the first jaw does not have an inductor. In this design, an inductor in the second jaw generates a high-frequency electromagnetic field, which induces eddy currents in the susceptor element of the first jaw, thereby generating a thermal pulse that is emitted by the susceptor element of the first jaw. An advantage of this design is that highly efficient cooling of the susceptor element can be provided, for example by placing at least one cooling fluid channel adjacent to the susceptor element, the cooling fluid channel extending, for example, along the rear side of the susceptor element, for example, parallel to the current-receiving element. In this design, the second jaw may also be cooled by the cooling device, for example by placing at least one cooling fluid channel adjacent the inductor, the cooling fluid channel extending, for example, along an elongated portion of the inductor, for example along its rear side . The disadvantage of the alternative design is that the distance between the current collecting element and the inductor depends on factors that may vary to some extent in practical application, such as wall thickness depending, for example, on the film material being processed, clamping force, etc. , which can negatively affect the accuracy and repeatability of the welding process. Therefore, in practice it is preferable to place the current collector and the inductor interacting with it in the same jaw.

The non-adhesive coating on the at least one current collector element may be replaceable such that only the non-adhesive coating needs to be replaced when it becomes worn or dirty, whereas prior art welding systems required replacement of the entire jaw.

In an embodiment of the welding system, at each of the welding stations, the at least one of the first and second jaws, which is cooled by a cooling device, comprises one or more cooling channels, and the cooling device continuously circulates a liquid coolant, such as water, according to one or more cooling channels. The channel is preferably formed as an opening in the plastic or ceramic jaw main body to provide direct contact between the liquid coolant and the main body. This embodiment also avoids excessive field variation caused by any other material that would form a channel for the liquid coolant.

In an embodiment, the control unit is configured to regulate the temperature and/or flow rate of the coolant circulating along the jaws, for example, depending on the output of the temperature sensor. By adjusting the temperature and/or flow rate of the coolant, the control unit can adjust the cooling capacity to provide a temperature reduction in the weld zone that optimally matches the weld to be formed.

In an embodiment, each cooling device includes a coolant temperature sensor for measuring and providing data on the actual coolant temperature, and/or a coolant flow sensor for measuring and reporting the flow rate of coolant circulating along the one or more jaws. , for example, separately for each jaw, and the control unit is configured to regulate the temperature and/or flow rate of the coolant circulating along the jaws, for example, separately for each jaw, depending on the output signal of the coolant temperature sensor and/or the coolant flow sensor. The coolant temperature sensor(s) may be configured to continuously measure the temperature of the coolant, such as the temperature of the coolant returning from the jaws or the temperature in the coolant reservoir, or may be configured to with the ability to output only the maximum values of the coolant temperature, for example, representing the maximum value of the coolant temperature for each of the pulse welding cycles. Upon detecting that the temperature of the coolant exceeds a predetermined temperature level, the control unit may decide to reduce the temperature of the coolant that is pumped toward the respective jaw and/or increase the flow rate of the coolant supplied to the corresponding jaw.

In an embodiment, each cooling device includes a permanently mounted pump and heat exchange assembly that is connected to the one or more movable welding station jaws via one or more flexible coolant hoses. In an embodiment, there is a specially provided, permanently installed pump and heat exchange unit for each welding station, possibly for each jaw. This, for example, makes it possible to improve independent cooling control, which, for example, allows working with individual temperature and coolant flow rates for each welding station or for each jaw.

In an embodiment, at least one welding station, preferably each welding station, comprises a temperature sensor interacting with the first jaw and/or the second jaw, for example located in the first jaw and/or the second jaw, wherein said sensor is connected to the control unit and configured with the ability to measure the actual temperature and provide data on the actual temperature of the corresponding jaw, for example, the front surface of the jaw and/or the current-receiving element of the jaw, if any. The control unit is configured to control heat sealing and/or cooling performed by the welding station based at least in part on the output signal of the temperature sensor. The temperature sensor may be configured to continuously measure the temperature of the corresponding sponge, for example its current collecting element, or may be capable of providing only a maximum temperature value, for example representing the maximum temperature value of the sponge for each cycle, or may be configured to determine the average temperature of the sponge , for example, its current-receiving elements, during the cycle.

In an embodiment, the control unit is configured to regulate the high-frequency current that is supplied to the inductor interacting with the current collector in the jaw of the welding station, depending on the output signal of the temperature sensor interacting with the jaw. By regulating the high-frequency electric current, for example, the magnitude of the current, the duration of the current supply, the distribution of the current values within the duration of the heat sealing pulse (for example, when energizing an inductor in the form of a sequence of periods of supplying different currents) and/or the frequency of the current, the control unit regulates the electromagnetic field , created by the corresponding inductor, thereby providing regulation of the eddy currents induced in the current-receiving element, and thereby the thermal impulse that is emitted by the current-receiving element.

In an embodiment, each jaw having an inductor and preferably also a current-receiving element has an inductor connected to a specially provided electric current source, wherein the control unit is configured to independently control each of the electric current sources to individually control a separate high-frequency current supplied to the corresponding inductor . This further facilitates individual control of the electromagnetic field generated by each inductor.

In an embodiment, the system is configured to implement a preheating step and operates to implement a preheating step in the cycle discussed herein, wherein the preheating is performed before the heat sealing pulse is actually applied. In practice, the preheating step is performed immediately before the heat seal pulse is applied.

In an embodiment, the control unit is configured to provide preheating before or while moving the jaws to the clamping position. In this case, the current collector element and/or the front surface of the jaw may reach a preheat temperature before the jaw comes into contact with the wall of the heat sealable film material. In an alternative embodiment, the control unit is configured to provide preheating while the jaws are in a clamping position, for example having just reached the clamping position.

The preheating step preferably includes generating a thermal pulse for preheating through the current collecting element(s) by supplying a high frequency electric current for preheating to an inductor to generate an electromagnetic field for preheating through the inductor, which provides preheating through the current collecting element. Preheating is preferably performed to a preheating temperature that avoids any melting of the film material. In this case, the subsequent heat-sealing pulse emitted by the current collector of the sponge provides the desired melting for heat-sealing.

When welding a fixture using a system according to the invention, for example in the production of bags, there is preferably no pre-heating of the fixture, eg the attachment part, before the cycle according to the invention is carried out at the fixture welding station. This avoids unnecessary dissipation of heat introduced into the fixture by such preheating, which is advantageous for reasons described herein.

As is known in the art, in an embodiment the loading section comprises a folding station which is configured to fold the film material dispensed from a single roll into two superimposed walls, optionally with a gusset , e.g. , forming the bottom fold of the package to be manufactured using a welding system.

In an embodiment, the control unit is configured to regulate at least the length of the stroke when moving the jaws along a straight path independently for each movement device provided at the welding stations. This, for example, makes it possible to have a stroke length that corresponds to the movement of the jaws in the clamping position. This, for example, avoids the situation in which, in the case where only a short stroke length is required in the clamping position, the jaws are moved with a larger stroke length. Particularly in high speed operations, such as bag making, limiting the actual stroke length is advantageous, for example due to considerations of mechanical forces due to acceleration/deceleration, wear of the movement device, etc. This embodiment, for example, allows for different jaw stroke lengths of different welding stations in a welding section.

In an embodiment, the control unit is configured to control the movement device provided at the first welding station and the movement device provided at the second welding station to adjust the position of the first and second jaws of the first welding station relative to the position of the first and second jaws of the second station welding, for example, to regulate the distance between them along a straight path. This is desirable, for example, for reasons related to the production of bags of different sizes.

In an embodiment, the welding system comprises a fixed frame, wherein the movement devices provided at successive welding stations are mounted on opposite sides of a straight path along which the superimposed walls move through the welding section, the walls superimposed on each other, have, for example, a vertical orientation when moving along the welding section, and the movement devices provided at successive welding stations are installed alternately below and above the straight path. For example, a fixture welding station has a movement device located below the path, wherein insertion of the fixture is accomplished by a fixture insertion device located above the path, for example inserting the fixture between unconnected edge regions of superimposed walls.

Each movement device contains, for example, a linear guide assembly, wherein the linear guide is attached to a stationary frame and runs parallel to a straight path. Here, the slider is mounted on a linear guide, and said slider is driven by a reciprocating drive. The slide provides support for the jaws of the welding station as well as for the corresponding drive device.

In an embodiment, at least one welding station, preferably each welding station, includes a position sensor in its first jaw and/or second jaw, which is connected to the control unit and configured to determine the position of the corresponding jaw and provide data on the position of the corresponding jaw, for example, in the direction of a straight path and/or a direction transverse to the straight path. The position sensor may determine the position relative to a fixed base, such as a fixed frame, and/or relative to walls of heat-sealable film material. In an embodiment, the control unit is configured to control the movement device provided at the welding station based on the output signal of the position sensor. The position sensor may be configured to continuously detect position and may be actuated to continuously detect the position of the corresponding jaw(s), or may be configured to detect only a specific position of the jaw(s), such as a home position in the beginning of each cycle or final position in which the jaws are moved to the opening position, for example at the end of the cooling phase.

In an embodiment, the position sensor is an optical sensor that is configured to obtain an image of the film material and detect marks that have been made on the film material. Such a mark, for example a printed mark, may indicate a corresponding location in the film material, for example indicating a location at which a cut is to be made at a later stage to produce individual packets, or may represent an alignment location between superimposed walls from film material. The optical sensor may be coupled to the control unit, and the control unit may be configured to control the device to provide movement based on an output of the optical sensor, for example, based on detection of a mark.

In an embodiment, the control unit is configured to operate on the basis of a feedback control mechanism, wherein one or more results of parameter measurements made during the first cycle form, at least in part, the basis for regulating pulse heating and/or cooling and/ or moving the jaws for one or more subsequent cycles.

In an embodiment, the control unit is configured with a memory and is operative to record one or more parameters, for example, one or more setting parameters and/or actual measured parameters related to pulsed heat sealing and/or cooling and/or movement of the welding station jaws, for example, during the production of bags. By recording the parameters, it can subsequently be possible to find out which weld, for example which package, was made under which specific settings. This can help monitor the quality of the welds produced.

In an embodiment, the control unit is provided with a memory in which, for example, for each welding station, a corresponding set of data is stored for a plurality of different weld configurations, for example, for the production of bags with multiple designs. The data set may contain, for example, settings relating to pulsed heating of the current collecting elements, for example, by means of an electrical current source(s), and/or relating to the operation of a cooling device, a driving device and/or a movement device. The stored parameters include, for example, one or more of a jaw clamping duration, a heat sealing pulse duration for each current collector, a cooling duration, a coolant temperature, a coolant flow rate. In embodiments, the data set may comprise clamping force and/or parameters related to the operation of the movement device, such as home position, travel end position, speeds, etc.

In an embodiment, the welding system comprises an operator input device, for example a touch screen, for example allowing the machine operator to select a weld configuration, for example based on a selection of stack design, wherein the control unit is configured to select a corresponding set of data suitably stored in a memory . This contributes to the flexibility of the welding system and allows for convenient switching between parameter settings for many different types of packages to be welded by the welding system, for example, different parameter settings for pulse heating, cooling, driving device and/or moving device, preferably No complex mechanical modifications to the welding system are required. In embodiments, there may not even be a need to change all the jaws when switching between different pouch designs.

In an embodiment, the welding system further comprises a display, such as a touch screen, configured to display a selected set of data in a graphical form, such as a graphical image or graphical images showing dimensions of, for example, a selected package, parameters related to heat sealing and cooling, etc. This display allows the operator to view relevant parameters and can provide a convenient way to check whether the welding system is set up correctly, for example to provide the correct weld configuration.

In an embodiment, each of the drive and/or movement devices comprises a servomotor. By means of the control unit, precise control of the servo motors can be achieved, which can enable the jaws to move accurately at high speeds to obtain high-quality welds.

In an embodiment, the welding section is provided with a trimming station located, for example, downstream of the welding stations, wherein the trimming station comprises:

- a trimming device configured to perform, on command, a trimming operation, for example, cutting, cutting, etc., to remove part of the webs superimposed on each other, for example, to give a certain shape to the contour of the package during the manufacture of packages;

- a device for providing movement, configured to ensure movement of the trimming device synchronously with the walls superimposed on each other when performing a trimming operation;

- a collection system configured to collect cut parts, for example comprising one or more vacuum hoses connected to a vacuum source.

The invention also relates to a process machine for making soft pouches, each of the pouches having walls formed from a heat sealable film material, preferably a metal free heat sealable film material, most preferably a single polymer heat sealable film material. The process machine contains the welding system described in this document.

In an embodiment, the machine is configured to produce bags having a device, for example a pourer element. In an embodiment, the first welding station provided along a straight path, that is, the station located on the upstream side of the welding section, is designed as a fixture welding station, which is configured to weld the fixture to superimposed walls by heat welding, for example between unconnected edge zones of the walls. In this case, one or more downstream welding stations are configured to weld one or more other areas of the stack, for example to produce a side seal and/or a bottom seal of the stack, while the walls still form part of a continuous strip, since the separation into individual packages is carried out downstream of the welding section.

The advantage of first heat sealing the fixture in the unconnected edge zone between the opposing walls, which is done before welding one or more other areas of the package to be heat sealed, is that the superimposed walls of film material can easily be separated from each other for insertion of the attached part fixtures in this open edge zone. The separation of the walls in a given edge zone is carried out, for example, by means of a wedge-shaped element, which is stationary and which separates the walls in the edge zone before they reach the position for inserting the device. This is done more easily - in particular at high speeds, which is made possible by the system according to the invention - than according to the prior art approach, which usually first forms one or more other heat welds, for example side welds seams connecting the walls of the bag to each other before welding the fixture in the unconnected edge zone by heat sealing. This prior art approach requires an opening device that is actuated and designed to move the walls away from each other and allow insertion of the fixture. In practice, this requires the walls to jump through the welding section or move at an undesirably low speed to move the walls away from each other.

In an embodiment, the machine comprises a fixture insertion device configured to insert an attachable portion of the fixture, e.g., a pourer, in an unconnected edge area between opposing walls, wherein the area is, for example, opposite the fold/turned portion connecting the opposing walls, e.g. a folded portion provided with a fold, for example to form a bottom fold/flat bottom of a bag. The station for welding devices is configured to weld the walls to opposite sides of the attached part of the device by means of heat welding.

In an embodiment, the fixture insertion device is configured to substantially simultaneously insert two attachment portions of two fixtures into an unconnected edge region of at least two adjacent stacks in one cycle by means of a single assembly consisting of first and second fixture insertion elements. Consequently, the fixture welding station is configured to weld the walls of two adjacent bags to opposite sides of both attachment parts of both fixtures by heat sealing in one cycle using one set consisting of the first and second jaws.

In an embodiment, the fixture welding station is configured to weld a plastic fixture having an attachable portion by heat sealing in an unconnected edge zone between opposing first and second walls formed from a heat sealable film material,

wherein each of the front surfaces of the first and second jaws of the fixture welding station has a recessed surface section, forming a recess made with the possibility of inserting half of the attached part of the fixture into it, and at the same time, on each of the front surfaces, coplanar surface sections are formed, located on opposite sides of the corresponding recessed surface and adjacent to said recessed surface,

wherein each of the first and second jaws of the fixture welding station contains, next to its respective front surface, at least one, for example, one elongated current-receiving element, which extends along the recessed surface portion and along the coplanar surface portions provided on the corresponding front surface,

wherein the fixture welding station is configured such that during operation the fixture is positioned such that its attached part is located in an unconnected edge zone between the opposite first and second walls formed from a heat-sealable film material, and

wherein the fixture welding station is configured to perform the cycle according to the invention described in this document.

In an embodiment, the fixture welding station is configured such that, during operation, the superimposed walls and the attachment portion of the fixture are placed between the first and second jaws of the station, and is configured such that the one or more current-receiving elements protrude above the unconnected edge zones of two adjacent packages, while the device welding station is configured to perform the cycle according to the invention described in this document.

The device may be, for example, a pouring member for discharging a product from a bag, such as a flowable product, such as a liquid product, such as a flowable food product, such as a beverage, sauce, etc. The device may have a neck that is closed or that is capable of being closed by a closure, such as a cap, such as a screw cap, a snap cap, a flip cap, etc. The device may include a valve, such as a bidon valve, a self-closing valve, such as a slot valve, etc.

Each pulse heated element of the fixture welding station is a susceptor element containing an electrically conductive material, wherein said susceptor element has a rear side facing away from a corresponding front surface of the jaw,

wherein each of the first and second jaws of the fixture welding station comprises an inductor that is electrically isolated from the corresponding current collector element, with each inductor extending along a respective front surface adjacent the rear side of the respective current collector element,

wherein a source of high-frequency electric current is connected to an inductor of each of the first and second jaws of the fixture welding station, and

wherein the fixture welding station is configured to perform the cycle according to the invention described in this document.

In an embodiment, the jaws of the fixture welding station are configured, for example, have such a current-receiving element, that the entire unconnected edge zone in which the fixture is inserted, for example, by a fixture inserter provided in the welding system, is welded in one cycle according to the invention, described in this document. In this way, both the fixation of the device in the edge zone and the heat sealing and closure of the entire corresponding edge zone are ensured. This avoids the need for additional welding operations along this edge zone.

In an alternative embodiment, the fixture welding station jaws are configured such that only a portion of the unconnected edge zone in which the fixture is located is welded in a given cycle, while the other portion of the unconnected edge zone remains open. This, for example, creates the possibility of subsequent filling of the package through the specified open part. This open portion is subsequently closed in another welding operation, for example based on pulsed heat sealing disclosed herein.

In an embodiment, the sealing system of the bag making machine includes a side seam welding station that is configured to heat seal two adjacent side zones of adjacent bags in a strip of bags while still connected to each other. In embodiments, the side seam welding station is located downstream of the fixture welding station when viewed along a straight path, for example, located between the fixture welding station and the lower zone welding station, if present.

In an embodiment, the side seam sealing station is configured to heat seal both side zones of a package and, for example, both corresponding side zones of adjacent packages in one cycle by means of a single set consisting of first and second jaws. In an embodiment, the side seam welding station is configured such that, in operation, superimposed walls are placed between its first and second jaws, and is configured such that the one or more current collecting elements protrude above both side zones of the stack and over both corresponding side zones of adjacent packages, wherein the side seam welding station is configured to perform the cycle according to the invention described in this document.

In an embodiment, the process machine for making bags includes a bottom zone sealing station, which is configured to heat seal the bottom zone of the bag.

During welding of soft bags without a bottom fold, the walls of the bag, connected, for example, by means of a folding zone, are pressed against each other directly in the lower zone by means of the jaws of the lower zone welding station. In this case, it may be sufficient to have one of the first and second jaws provided with the current collecting element and the inductor, while the other jaw is designed and functions simply as a passive counter jaw, whereby, for example, the passive jaw is cooled.

In an embodiment, the bottom zone welding station is configured to heat seal the bottom zones of at least two adjacent stacks in one cycle by means of one set consisting of first and second jaws. In an embodiment, the lower zone welding station is configured such that, during operation, superimposed walls are placed between its first and second jaws, and is configured such that the one or more current collecting elements protrude above the lower zones of two adjacent stacks , over at least a portion of each of the two lower zones, wherein the lower zone welding station is configured to perform the cycle according to the invention described herein.

Each pulse-heated element of the lower zone welding station is a current-receiving element containing electrically conductive material, and the current-receiving element has a rear side facing away from the corresponding front surface of the jaw,

Moreover, each current-receiving element of the lower zone welding station has a front surface, which is made in the form of an inverted letter T, so that the thermal pulse ensures welding of at least part of the lateral edge zones of two adjacent packages, as well as welding of at least part of the lower edge zones of each of two adjacent packages,

wherein at least one, preferably each, of the first and second jaws of the lower zone welding station comprises an inductor that is electrically isolated from a corresponding current collecting element, wherein each inductor includes an elongated inductor portion that extends along a rear side of the elongated portion of the current collecting element having the shape inverted letter T,

wherein the source of high-frequency electric current is connected to the inductor, and

wherein the lower zone welding station is configured to perform the cycle according to the invention described in this document.

In an embodiment, the lower zone welding station inductor is shaped like an inverted T and includes first, second and third inductor components, wherein each inductor component includes a plurality of elongated inductor portions parallel to each other, such as separated from each other by a slot, wherein the plurality of elongated inductor portions are the inductor parts provided in the inductor component are connected to each other in series, for example, by a curved inductor portion at an outer end of the inverted T-shaped inductor component. Three elongated current collecting parts of the inverted T-shaped current collecting element can be connected to each other another in the central part of the current-receiving element. In operation, the first of the elongated current-receiving portions may extend toward an upper end of the stacks and may extend above the side edges of two adjacent stacks, for example, at least above the bottom of said side edges. Thereby, during operation, this upper elongated current receiving part can ensure at least partial welding of the side edges of adjacent packages.

In an embodiment of a bag making machine for making bags with a bottom fold/flat bottom, each of the first and second jaws of the bottom zone welding station is provided with a current collector element and an inductor for welding the first part of the bottom fold to the first wall and welding the second part of the bottom fold to the second wall.

In the manufacture of soft pouches having a bottom fold/flat bottom, the stacked walls are fed to a bottom sealing station in a folded configuration formed by a first wall, a first bottom fold portion, a second bottom fold portion, and a second wall typically with a W-shape, as is known in the art. In addition, as is known in the art, there is a so-called triple point on each of the side edges of the bottom gusset/flat bottom pouch, wherein above the triple point the first and second walls are in direct contact with each other, and wherein under the triple point, two parts of the bottom fold are located between the first and second walls. Therefore, at the triple point, the thickness changes from a thickness of twice the wall thickness to a thickness of four times the wall thickness. It is well known that near this transition zone, heat sealing using existing welding technologies is difficult. The inverted T design can be used for bottom fold welding, including the triple point.

When making flat bottom/bottom gusset bags, precise heat control ensures that in the portion of the bag near and below the triple point, sufficient heat is supplied to weld each bottom gusset portion to the corresponding first or second wall, and that the amount of heat does not will be too large to prevent the bottom fold parts from welding to each other.

The uniformity of the pulsed heat sealing process allows for minimal clamping force to be generated by the jaws in the clamping position, for example significantly less force than with traditional, continuously heated welding jaws. The clamping force can actually only serve to guarantee tight contact between the surfaces of the walls of the bag and the parts of the bottom fold located inside, if any.

For sealing the bottom zones of bags with a bottom fold/flat bottom, the clamping force may be chosen greater than the clamping force for welding the bottom zones without a bottom fold, for example, for reasons related to the reliable displacement of air from the clamped parts of the bag, for example, at the triple point.

In an embodiment, the process machine for making bags is designed so that the straight path along which the walls move through the sealing section is horizontal, while the loading section is configured to fold the film material dispensed from one roll in the form of two walls superimposed on each other each other, with the superimposed walls having a vertical orientation as they are fed into the welding section with an unconnected upper edge zone between the opposing walls and a fold/folded area along the underside of the opposing walls, optionally with a bottom fold formed by folding along the lower side of the opposite walls, wherein a device insertion device is provided, which is configured to insert the attached part of the device in the unconnected upper edge zone between the opposite walls, while the device insertion device is, for example, mounted stationary on the stationary frame of the machine, and the device for providing movement provided at the corresponding fixture welding station is installed under the straight path, wherein said movement device comprises, for example, a linear guide assembly provided with a linear guide attached to a fixed frame parallel to this straight path, and a slider mounted on the linear path guiding and driven by a reciprocating drive, the slide providing support for the jaws of the welding station as well as for the corresponding drive device.

In embodiments, the machine includes a cutting station that is located downstream of the film material driving station and is configured to make one or more cuts to create individual pouches.

In embodiments, the system is provided with a filling section located downstream of the sealing section for filling individual bags. For example, filling is carried out through a device or through an unwelded open area between the walls intended for filling and located, for example, next to the device. This open fill area is then welded using another welding device.

The present invention also relates to a sealing station disclosed herein for heat sealing a heat sealable film material, preferably a metal free heat sealable film material, such as a single polymer heat sealable film material.

The present invention also relates to the combination of a welding station described herein, comprising two or more welding stations located in series along a straight path, and a film material driving station that is located downstream of a straight path passing through the welding section, wherein said station for driving the film material is configured to ensure the movement of walls of heat-sealable film material, superimposed on each other, under the action of a pulling force at a constant speed along a straight path beyond the welding station.

Furthermore, the present invention relates to a jaw or a pair of jaws, consisting of the first and second jaws disclosed herein, configured to be used in a sealing station to heat seal a heat sealable film material, preferably a metal free heat sealable film material, e.g. film material made from one polymer.

The present invention also relates to a method for heat sealing a heat sealable film material, preferably a metal free heat sealable film material, for example a single polymer heat sealable film material, for example in the manufacture of bags, for example bags equipped with a device, wherein the method uses a sealing station , disclosed herein, and/or a combination of a welding section described herein and comprising two or more welding stations located sequentially along a straight path, and a film material driving station that is located downstream of a straight path passing through the welding station. a section described herein and/or a jaw or pair of jaws consisting of the first and second jaws disclosed herein for use in a welding station.

Additional features of the invention will be explained below with reference to embodiments, which are shown in the accompanying drawings, in which:

FIG. 1 shows an embodiment of a welding system in a bag making machine according to the present invention; FIG.

FIG. 2 shows the loading section of the welding system of FIG. 1;

FIG. 3 shows a punching station provided in the welding system of FIG. 1;

FIG. 4A shows a fixture welding station provided in the welding system of FIG. 1;

FIG. 4B shows an enlarged view of the fixture welding station of FIG. 4A;

FIG. 5A shows a side seam welding station and a bottom zone welding station provided in the welding system of FIG. 1;

FIG. 5B shows an enlarged view of the side seam welding station of FIG. 5A;

FIG. 5C shows an enlarged view of the lower zone welding station of FIG. 5A;

FIG. 6 shows a film material driving station provided in the welding system of FIG. 1;

FIG. 7 shows a cutting station provided in the welding system of FIG. 1;

Fig. 8 shows the sponge of the fixture welding station according to Fig. 4A;

FIG. 9 shows the jaw of the side seam welding station of FIG. 5A;

Fig. 10 shows the jaw of the lower zone welding station of Fig. 5A;

FIG. 11 shows a schematic diagram of the welding system of FIG. 1;

Fig. 12 schematically illustrates the operation of a welding station with continuous movement of the material being welded;

FIG. 13 schematically shows the current-receiving element and inductor of FIG. 8;

Fig. 14 schematically shows a cross-section of a sponge including a current-receiving element and an inductor;

Fig. 15 schematically shows a cross-section of a sponge including a current-receiving element, an inductor and an elastic support layer of the current-receiving element; And

FIGS. 16A, B, C schematically show the electromagnetic field generated by the sponge of FIG. 8 and the interaction with the current collecting element.

Throughout the figures, the same reference numerals are used to designate corresponding components or components having a corresponding function.

FIG. 1 shows an embodiment of a welding system according to the present invention, designated by the reference numeral 1. The welding system 1 includes, when viewed along a straight path (T), a first welding station, a second welding station and a third welding station, configured respectively as a fixture welding station 10 , station 20 for welding side seams and station 30 for welding lower zones.

The welding stations 10, 20, 30 are arranged in series, each configured to heat seal a wall 101 formed of a heat sealable film material, preferably a metal free heat sealable film material, such as a heat sealable film material of one polymer, superimposed on one another. a wall 102 of a heat-sealable film material, preferably a metal-free heat-sealable film material, such as a single-polymer heat-sealable film material, and a tool, if any, for creating in each case a corresponding sealed zone in the manufacture of bags 100.

At the fixture welding station 10, a plastic fixture 150 is placed between the walls 101, 102. The fixtures 150 are fed from the fixture storage 90 via two adjacent guides 91. Accordingly, two fixtures 150 are simultaneously placed in two respective unconnected edge regions between the walls 101, 102. As shown In an embodiment, the devices are made in the form of pouring elements 150 for releasing the product from the bag 100.

At the fixture welding station 10, the plastic fixture 150 by means of its attached part 151 welded between walls 101, 102 superimposed on each other. Prior to this welding operation, the two walls 101, 102 are not yet welded to each other. As a result, the walls can simply be held apart from each other for insertion of the fixture 150. Once welded, the fixture 150 remains in place between the walls 101, 102.

According to the present invention, the fixture welding station 10 is configured to weld two fixtures 150 substantially simultaneously in two respective zones between the walls 101, 102 by means of two sets of fixture welding jaws.

The side seam welding station 20 is configured to heat seal two adjacent side zones of adjacent pouches in a strip of pouches 100 while still attached to each other to form a side or vertical seal of the pouch 100. In the illustrated embodiment, the side seal in the pouch 100 is bottom gusseted. /flat bottom passes through the triple point where the top of the bottom fold portion is adjacent to the side of the bag 100.

According to the illustrated embodiment, the side seam welding station 20 is configured to simultaneously form two side welds between the walls 101, 102 by means of two sets of side seam welding jaws.

The bottom zone welding station 30 is configured to form a bottom fold/flat bottom weld of the package 100, such as a bottom weld between opposing side edges of the package 100. The welding system of this embodiment is configured to ensure that the entire bottom fold weld of the package 100 can be formed with only one heat pulse, which ensures fast and reliable welding of the bottom fold.

According to the presented embodiment, the bottom zone welding station 30 is configured to simultaneously heat seal two bottom fold zones by means of two sets of bottom fold zone welding jaws.

The sealing system includes a loading section with a roll handling station 40 configured to receive multiple rolls of heat sealable film material. Station 40 for handling rolls is located along the path in front of welding stations 10, 20, 30, when viewed along a straight path (T). The loading section is configured to dispense superimposed walls 101, 102 of heat-sealable film material formed from a single polymer and unwound from rolls.

The welding system 1 forms part of a technological machine for making bags, which additionally has a loading section configured and operative to convert the film material dispensed by the roll handling station 40 into a belt of stacks 100 connected to each other, each stack 100 having a bottom fold in its lower area formed by two folded lower curved protrusions located below the triple point in package 100.

The loading section further comprises a folding station 50 located downstream of the roll handling station 40 and configured to fold the film material dispensed from one roll into two superimposed walls 101, 102 with a bottom fold.

The welding system 1 further includes a film material driving station 60, which is configured to allow the walls 101, 102 of the heat-sealable film material to be welded to move under the action of a pulling force along a straight, for example, horizontal path (T) at a constant speed, at In this case, said path runs along the folding station 50 and the welding stations 10, 20, 30. When viewed along a straight path (T), the driving station 60 is located downstream of the welding stations 10, 20, 30.

Downstream of the driving station 60 is a cutting station 70 that is configured to make one or more cuts to shape the bags 100 and separate the bags 100.

The welding system 1 further includes a punching station 45 that is located along a path (T) between the roll handling station 40 and the folding station 50, as best shown in FIG. 2. The perforation station 45 is configured to punch holes in the film material to enable two protruding parts of the bottom fold having a curved shape to be welded to each other. This is made possible by perforations that ensure that the outer walls of the fold face each other immediately after folding the film material.

The perforation station 45 is shown in more detail in FIG. 3 and includes a frame portion 46 that is rigidly attached to the stationary frame of the welding system 1 and is configured to remain stationary. The frame portion 46 includes a plurality of straight cylindrical guide shafts 47 that extend in the length direction. The cylindrical guide shafts 47 are rigidly attached to the frame portion 46 and are therefore also configured to remain stationary. The punching station 45 includes a set of punching jaws 48 that are slidably attached to the cylindrical guide shafts 47 via slide bearings 49. Each of the slide supports 49 surrounds a cylindrical guide shaft 47, and the slide supports 49 are configured to allow the punching jaws 48 to move relative to the frame portion 46 only along a punching path (P) aligned, for example, in the horizontal direction. The punching path (P) is aligned parallel to the path of the film material adjacent to the punching station 45.

In the illustrated embodiment, the welding system 1 includes a movement device provided at the punching station 45 and not shown in FIGS. 2 and 3, which is designed to move the punching jaws 48 in synchronization with the continuously moving film material along a given path relative to the frame portion 46 .

The folding station 50 includes a plurality of rollers 51 for guiding the unwound film material in an appropriate direction. Downstream of the rollers 51, the folding station 50 includes a first folding plate 52 for folding the film material into two superimposed walls 101, 102. Downstream of the first folding plate 52, the folding station 50 includes a second folding plate 53 for folding the respective lower portions of the superimposed walls 101, 102 into two folded lower curved projections located below the triple point of the stack 100.

In FIGS. 4A and 4B, the fixture welding station 10 is shown in more detail. The fixture welding station 10 is configured to weld a plastic fixture 150 having an attachment portion 151 by heat sealing in an unconnected edge region between the opposing first and second walls 101, 102 formed of a heat sealable film material. The fixtures 150 are fed toward the fixture welding station 10 via two guides 91 that are located adjacent to each other. At the end of each of the rails 91 there is a corresponding servo-operated closure 92 for holding the tool 150 in place at the end of each rail 91.

The advantage of first heat sealing the fixture 150 in the unconnected edge zone between the opposing walls 101, 102, before welding one or more other areas of the stack 100 to be heat sealed, is that the superimposed film material walls 101, 102 can be easily separated from each other. from each other to insert the attachment portion 151 of the device 150 into this open edge area. In the illustrated embodiment, the separation of the walls from each other in a given edge zone is accomplished by a wedge-shaped element, which is stationary and which separates the walls 101, 102 in the edge zone before they reach the position for insertion of the device.

The welding system 1 further includes two fixture insertion elements 93, which are located above the fixture welding station 10 and each of which is configured to engage the fixture 150 adjacent to the servo-operated shutter 92, causing said shutter 92 to open, for example. Each fixture insertion member 93 is configured to carry the fixture 150 with its attachment portion 151 into an unconnected edge region between the first heat-sealable film material wall 101 and the second heat-sealable film material wall 102. To achieve this, the fixture insertion member 93 is configured to perform a rotational movement while simultaneously clamping the fixture 150. Essentially, the fixture 150 is lowered so that its attachable portion is positioned between the walls 101, 102.

The fixture welding station 10 includes first jaws 11 and second jaws 12, between which walls 101, 102 of heat-sealable film material are placed. The two first jaws 11, 11' are located next to each other and opposite the two second jaws 12, 12', not visible in FIGS. 4A and 4B. In FIG. 8, one of the jaws 11 of the fixture welding station 10 is shown in more detail and will be described later. Each first jaw 11 has a first front surface configured to contact a corresponding edge region of the first wall 101, and each second jaw 12 has a second front surface configured to contact a corresponding edge zone of the second wall 102.

The station 10 for welding devices contains two drive devices 13, made in the presented embodiment, for example, in the form of servo motors and designed to ensure movement of the jaws 11, 12 relative to each other between the opening position and the clamping position. The first 13 of the drive devices is configured to allow movement of the first set of jaws 11, 12, and the second 13' of the drive devices is configured to allow movement of the second set of jaws 11', 12'. Each drive device 13 is configured to hold its respective first jaw 11 and second jaw 12 in a closed position for a corresponding clamping time. The drive devices 13, 13' are designed to operate independently of each other, which means that the first set of jaws 11, 12 can be moved between the opening and clamping positions independently of the second set of jaws 11', 12'.

The fixture welding station 10 additionally contains a cooling device 14, which is configured to continuously cool both the first jaws 11 and the second jaws 12.

The fixture welding station 10 is configured to perform a pulse welding cycle through each set of jaws 11, 12. Each drive device 13 is configured to move its corresponding first jaw 11 and second jaw 12 to a clamping position so that the areas overlap each other, the first wall 101 and the second wall 102 are pressed against each other by means of the first jaw 11 and the second jaw 12.

The fixture welding station 10 is configured to temporarily excite each susceptor element in the clamping position to generate a thermal pulse emitted by each susceptor element. The heat pulse causes the zones of the first wall 101 and the second wall 102 to be welded to each other. Both the first jaw 11 and the second jaw 12 are cooled by the cooling device 14 after completion of excitation of the current collecting element, since they are cooled continuously, for example. Each drive device 13 is configured to cause its respective first jaw 11 and second jaw 12 to move to the opening position after the current collecting element has cooled. Since the jaws 11, 12 of the fixture welding station 10 and the heat sealable film material walls 101, 102 are cooled in the clamping position, their temperature is relatively low when the jaws 11, 12 are moved to their opening position.

The jaws 11, 12 of the fixture welding station 10 are arranged to slide in the welding system 1. For this purpose, the welding system 1 contains a plurality of lower linear guides 3 that extend in the length direction. The lower linear guides 3 are rigidly attached to the stationary frame 2 of the welding system 1 in its lower zone and are also configured to remain stationary. The jaws 11, 12 are slidably attached to the lower linear guides 3 by means of sliding supports, each of which surrounds the linear guide and which are configured in such a way that they allow the jaws 11, 12 to move relative to the frame 2 only in the horizontal direction along a straight path ( T) movement of film material.

The fixture welding station 10 further comprises a movement device 15 configured to cause its corresponding first jaws 11 and second jaws 12 to reciprocate in synchronization with the continuously moving walls 101, 102 to be welded during a pulse welding cycle, for example, when they are clamped between the jaws 11, 12. In the illustrated embodiment, reciprocating movement refers to the back and forth movement of the jaws 11, 12, during which the jaws 11, 12 stop at the end of the stroke to move backwards in the opposite direction. At station 10 for welding devices, the total stroke length is determined by the product of the sum of the duration of the heat pulse and the cooling time in the clamping position and the speed of movement of the walls 101, 102 superimposed on each other.

During operation, the jaws 11, 12 of the fixture welding station 10 are moved to a clamping position by the drive device 13 once the fixture 150 is inserted between the superimposed walls 101, 102. At this point, the attachment portion 151 of the fixture 150 is clamped between the walls 101, 102, for example, between the jaws 11, 12 of the fixture welding station 10. Accordingly, the fixture 150 moves along with the walls 101, 102 and jaws 11, 12 along a straight path (T) during welding.

Downstream of the fixture welding station 10, a side seam welding station 20 is provided for heat sealing two adjacent side zones of adjacent packages 100, as best illustrated in FIGS. 5A and 5B. Similar to the fixture welding station 10, the side seam welding station 20 includes first jaws 21 and second jaws 22, between which walls 101, 102 of heat-sealable film material are placed. The two first jaws 21, 21' are located adjacent to each other and opposite the two second jaws 22, 22', of which only one jaw 22 is visible in FIGS. 5A and 5B. One of the jaws 21 of the side seam welding station 20 is shown in more detail in FIG. 9 and will be described later. Each first jaw 21 has a first front surface configured to contact a corresponding side region of the first wall 101, and each second jaw 22 has a second front surface configured to contact a corresponding side region of the second wall 102.

The side seam welding station 20 additionally contains a drive device 23, made in the embodiment shown, for example, in the form of a servo motor and designed to ensure movement of the jaws 21, 22 relative to each other between the opening position and the clamping position. The first jaws 21, 21' are connected to each other to move them together, and the second jaws 22, 22' are connected to each other to move them together.

The side seam welding station 20 further includes a cooling device 24 configured to continuously cool both the first jaws 21 and the second jaws 22.

The side seam welding station 20 is configured to perform a pulse welding cycle through each set of jaws 21, 22, which is similar to the pulse welding cycle performed at the fixture welding station 10. However, at the side seam welding station 20, a side weld is formed, for example, a vertical side weld between every two adjacent stacks 100. Moreover, each set of jaws 21, 22 is configured to form one side weld, which means that two side welds are formed simultaneously welds, for example, one for each set of jaws.

The jaws 21, 22 of the side seam welding station 20 are slidably positioned in the welding system 1. For this purpose, the welding system 1 includes a plurality of upper linear guides 4 that extend in the length direction. The upper linear guides 4 are rigidly attached to the stationary frame 2 in its upper zone and are designed to remain stationary. The jaws 21, 22 are slidably attached to the upper linear guides 4 by means of sliding supports, each of which surrounds the linear guide and which are configured in such a way that they allow the jaws 21, 22 to move relative to the frame 2 only in the horizontal direction along a straight path ( T) movement of film material.

The side seam welding station 20 also includes a movement device 25, not visible in FIGS. 5A and 5B, which is configured to allow corresponding first jaws 21 and second jaws 22 to reciprocate in synchronization with the continuously moving walls 101, 102 to be welding, during a pulse welding cycle, for example when they are clamped between the jaws 21, 22. In the illustrated embodiment, reciprocating movement refers to the back and forth movement of the jaws 21, 22, during which the jaws 21, 22 stop at the end of the stroke to moving backwards in the opposite direction. At the side seam welding station 20, the total stroke length is determined by the product of the sum of the duration of the heat pulse and the cooling time in the clamping position and the speed of movement of the walls 101, 102 superimposed on each other.

Downstream of the side seam welding station 20 is a bottom zone welding station 30 for heat sealing the bottom zones of the bags 100, as best shown in FIGS. 5A and 5C. Similar to the side seam welding station 20, the bottom zone welding station 30 includes first jaws 31 and second jaws 32, between which walls 101, 102 of heat-sealable film material are placed. The two first jaws 31, 31' are located adjacent to each other and opposite the two second jaws 32, 32', of which only one jaw 32 is visible in FIGS. 5A and 5C. One of the jaws 31 of the lower zone welding station 30 is shown in more detail in FIG. 10 and will be described later. Each first jaw 31 has a first front surface configured to contact a corresponding bottom fold area formed by the first wall 101, and each second jaw 32 has a second front surface configured to contact a corresponding bottom fold area formed by the second wall 102.

The lower zone welding station 30 further comprises a drive device 33, designed in the embodiment shown, for example, in the form of a servo motor, and designed to ensure movement of the jaws 31, 32 relative to each other between the opening position and the clamping position. The first jaws 31, 31' are connected to each other to move them together, and the second jaws 32, 32' are connected to each other to move them together.

The lower zone welding station 30 further includes a cooling device 34 configured to continuously cool both the first jaws 31 and the second jaws 32.

The bottom zone welding station 30 is configured to perform a pulse welding cycle through each set of jaws 31, 32, which is similar to the pulse welding cycle performed at the side seam welding station 20. However, at the bottom zone welding station 30, a bottom zone weld, such as a bottom fold weld, is formed separately for each individual stack 100. Moreover, each set of jaws is configured to form one bottom zone weld, which means that two welds are formed simultaneously seam of the lower zones, for example, one for each set of jaws.

Both sets of jaws 31, 32 are located at a relatively large distance from each other along the trajectory (T), and the distance between them is equal, for example, to the width of the package, which is provided to prevent mutual influence of the current-receiving elements of both sets of jaws 31, 32. In general, the length The lower zone welding station 30 corresponds to four packages 100, of which two are welded in each pulse welding cycle.

The jaws 31, 32 of the lower zone welding stations 30 are slidably positioned in the welding system 1. The jaws 31, 32 are slidably attached to the lower linear guides 3 by means of sliding supports, each of which surrounds the linear guide and which are configured such that they provide the ability to move the jaws 31, 32 relative to the fixed frame 2 only in the horizontal direction along the straight path (T) of movement of the film material.

The lower zone welding station 30 also includes a movement device 35, not visible in FIGS. 5A and 5C, which is configured to allow corresponding first jaws 31 and second jaws 32 to reciprocate in synchronization with the continuously moving walls 101, 102. to be welded during a pulse welding cycle, for example when they are clamped between the jaws 31, 32. In the illustrated embodiment, reciprocating movement refers to the back and forth movement of the jaws 31, 32, during which the jaws 31, 32 stop at the end of the stroke to move backwards in the opposite direction. At station 30 for welding the lower zones, the total stroke length is determined by the product of the sum of the duration of the heat pulse and the cooling time in the clamping position and the speed of movement of the walls 101, 102 superimposed on each other.

Downstream of the lower zone welding station 30, the welding system includes a trimming station 55, which is configured to trim the top and bottom corners of the packages 100 in a strip of packages still connected to each other to shape the contours of the packages 100. Trimming devices 56, e.g. , the punching or cutting devices provided at the trimming station 55 are slidably arranged on the lower linear guides 3 substantially similar to the fixture welding station 10 and the lower zone welding station 30, and the trimming station 55 includes a specially provided movement device for allowing the cutting devices 56 to slide relative to the lower linear guides 3. The cutting station 55 further includes a vacuum collection system provided with a vacuum source and a number of vacuum hoses 57 and configured to remove cut pieces of bags 100 away from the cutting devices 56.

Downstream of the cutting station 55, the welding system 1 includes a film material driving station 60, which is provided with rollers 61 located on opposite sides of the walls 101, 102 to be welded. The opposite rollers 61 are configured to clamp the walls 101, 102 between them and are configured with the possibility of setting the walls 101, 102 in motion, for example, by means of an electric motor 62 to move the walls 101, 102 under the action of a pulling force when the rollers 61 rotate.

A cutting station 70, configured to produce individual bags 100, is located downstream of the driving station 60, for example, in a location where there is no pulling force acting on the belt of bags 100 connected to each other. The cutting station 70 contains a plurality of axially spaced sets of cutting knives, in this case two sets of one or more movable cutting knives. In this case, each set contains a first knife 71 facing the first wall 101 and a second knife 72 facing the second wall 102 of sealed bags, which still have the appearance of a strip of bags connected to each other. The knives 71, 72 are configured to make a cut between the welded side regions of adjacent bags 100. During cutting, the knives 71, 72 are moved toward each other to cut each bag 100, for example, through a scissor-like shearing action between the knives 71, 72.

The cutting station 70 further includes a drive device 73, configured as illustrated, for example, in the form of a servo motor, and designed to move the knives 71, 72 relative to each other to perform cutting. To move the knives 71, 72, the drive device 73 is connected to the knives 71, 72 through a rotating shaft 74 and a rocker mechanism 74. The first knives 71, 71' are connected to each other to move them together, and the second knives 72, 72' are also connected to each other. friend to move them together.

The cutting station 70 is configured to perform a cutting operation to separate a strip of bundles 100 connected to each other to produce individual bundles 100.

6 illustrates pouch picking devices 120 configured to pick up each pouch 100. For example, pouch picking devices 120 are configured to transfer pouches 100 to a filling section of a machine, for example, to fill and seal filled pouches 100. In another embodiment of the device. The pouch pickers 120 move pouches onto transport guides where fixtures are inserted into the pouch guide to group the pouches.

In the example shown, each cut is made by each set of opposing knives 71, 72. Each set of knives is configured to make one vertical side cut, which means that two vertical side cuts, for example one for each set of knives, are made simultaneously. Accordingly, two separated individual packets 100 are obtained through each cutting cycle.

The knives 71, 72 of the cutting station 70 are slidably located in the machine. For this purpose, the machine contains one or more linear guides 5 that extend in the axial direction. Linear guides 5 are attached to a fixed frame 2. Jaws 71, 72 are installed on a slider, which is mounted on linear guides 5 with the ability to slide.

The cutting station 70 may also include a movement device configured to cause the knives 71, 72 to reciprocate in synchronization with the continuously moving packages 100, for example, at least while making a cut. In the illustrated embodiment, reciprocating movement refers to the back and forth movement of the knives 71, 72, during which the knives 71, 72 stop at the end of the stroke to move back in the opposite direction.

8 shows that each fixture welding jaw 11 has a front surface 111 on which a recess 112 is formed to receive half of the attachment portion 151 of the fixture 150. In addition, coplanar surface portions 113 are formed on the first front surface 111 , located on opposite sides of the corresponding recessed surface 112 and adjacent to the specified recessed surface 112. The front surface 111 of the jaw 11 is formed by a pulse-heated element, which is made in the form of a current-receiving element 114, coated with a heat-resistant non-adhesive coating. The current collecting element 114 extends along the recessed surface portion 112 and coplanar surface portions 113 on the corresponding front surface 111. In operation, the fixture 150 is positioned such that its attachment portion 151 is located in an unconnected edge region between the opposing first and second walls 101, 102 formed from heat sealable film material.

Each of the jaws 11 is configured with a current collector element 114 that contains electrically conductive material and has a rear side facing away from a corresponding front surface 111. In addition, each jaw 11 includes an inductor 115 that is electrically isolated from the current collector element 114. The inductor 115 includes an elongated a portion of the inductor that extends along a corresponding front surface 111 adjacent the rear side of the current collecting element 114, making the inductor 115 invisible in FIG. 8.

The fixture welding station 10 includes a high-frequency electric current source 16, which is connected to an inductor 115 of each of the first jaws 11, 11' and the second jaws 12, 12' of the fixture welding station 10 through respective connecting terminals 117. The fixture welding station 10 is configured such that that in the pulse welding cycle, its electric current source 16 is actuated to temporarily supply a high-frequency electric current to the inductors 115 of the fixture welding station 10, whereby the inductors 115 create a high-frequency electromagnetic field. The high-frequency electromagnetic field induces eddy currents in the corresponding current collector element 114, generating a thermal pulse that is emitted by the current collector element 114. The thermal impulses cause the edge zone of the walls 101, 102 to be welded to the attachment portion 151 of the fixture 150 and to each other.

The jaws 11 of the fixture welding station 10 are configured, for example, of such a length (L), that the entire unconnected edge zone in which the fixture 150 is inserted is welded in one cycle by the operation of the jaws 11. Thus, they provide both fixation of the fixture 150 in the edge zone, as well as welding and closing the entire edge zone.

The fixture welding jaw 11 is cooled by a cooling device 14 of the fixture welding station 10 and contains two cooling channels 118, for example, one inlet channel for directing coolant to the jaw 11 and one output channel for directing coolant from the jaw 11. The cooling device 14 includes a fixedly mounted pump and a heat exchange system that is connected to the cooling channels 118, and the cooling device 14 is configured to provide continuous circulation of a coolant, for example water, through the cooling channels 118, for example, during the entire pulse welding cycle.

FIG. 9 shows the welding jaw 21 of the side seam welding station 20. This side seam welding jaw 21 has a substantially flat front surface 211 designed to contact the side areas of the walls 101, 102 of, for example, two adjacent stacks 100 connected to each other. The front surface 211 is formed by a pulse-heated element, which is made in the form of a current-receiving element 214, coated with a heat-resistant non-adhesive coating.

Each of the jaws 21 is configured with a current collector element 214 that contains electrically conductive material and has a rear side facing away from a corresponding front surface 211. In addition, each jaw 21 includes an inductor 215 that is electrically isolated from the current collector element 214. The inductor 215 includes two elongated inductor portions 216 that extend along a corresponding front surface 211 adjacent the rear side of the current collector element 214. The inductor 215 is longer than the current collector element 214 and extends below the current collector element 214, with two parallel inductor portions 216 shown.

The side seam welding station 20 includes a high-frequency electric current source 26, which is connected to an inductor 215 of each of the first jaws 21, 21' and the second jaws 22, 22' of the side seam welding station 20 through respective connecting clamps 217. The side seam welding station 20 is configured with such a configuration that, in a pulse welding cycle, its electric current source 26 is driven to temporarily supply high-frequency electric current to the inductors 215 of the side seam welding station 20, whereby the inductors 215 generate a high-frequency electromagnetic field. The high-frequency electromagnetic field induces eddy currents in the corresponding current collector element 214, generating a thermal pulse that is emitted by the current collector element 214. The thermal impulses cause the side zones of the walls 101, 102 to be welded to each other to form side welds, for example, vertical side welds of the packages 100.

The side seam welding jaw 21 is cooled by the cooling device 24 of the side seam welding station 20 and includes two cooling channels 218, for example, one inlet channel for directing coolant to the jaw 21 and one outlet channel for directing coolant from the jaw 21. The cooling device 24 contains stationary an installed pumping and heat exchange system that is connected to the cooling channels 218, and the cooling device 24 is configured to ensure continuous circulation of a coolant, for example water, through the cooling channels 218, for example, during the entire pulse welding cycle.

Figure 10 shows the welding jaw 31 of the lower zone welding station 30. This lower zone welding jaw 31 has a substantially flat front surface 311 designed to contact the bottom zones of the walls 101, 102, for example, to contact the bottom fold areas of the package 100. The front surface 311 is formed by a pulse heated element, which is designed as a current collector element 314 coated with a heat-resistant non-stick coating.

The susceptor element 314 has a curved shape, with the side edges of the susceptor element 314 located above the central zone of the susceptor element 314. The shape of the welded zone of the bottom fold of the package 100 is determined by the shape of the susceptor element 314, as a result of which the presented susceptor element 314 is configured to provide a curved weld seam of the bottom fold. This curved bottom fold weld curves upward toward both sides of each stack 100 toward a triple point that is present on each of the side edges of the stack 100. Above the triple point, the first wall 101 and the second wall 102 are in direct contact with each other, and below the triple point, two parts of the bottom fold are located between the first wall 101 and the second wall 102.

Each of the jaws 31 is configured with a current collector element 314 that contains electrically conductive material and has a rear side facing away from the corresponding front surface 311. In addition, each jaw 31 includes an inductor 315 that is electrically isolated from the current collector element 314. The inductor 315 includes two elongated inductor portions 316 that extend along a corresponding front surface 311 adjacent the rear side of the current collector element 314. The inductor 315 is wider than the current collector element 314 and extends beyond the current collector element 314 at its lateral edges, with two parallel inductor portions 316 shown .

The lower zone welding station 30 includes a high-frequency electric current source 36, which is connected to an inductor 315 of each of the first jaws 31, 31' and the second jaws 22, 32' of the lower zone welding station 30 through corresponding connecting clamps 317. The lower zone welding station 30 is configured with such a configuration that, in a pulse welding cycle, its electric current source 36 is driven to temporarily supply high-frequency electric current to the inductors 315 of the lower zone welding station 30, whereby the inductors 315 generate a high-frequency electromagnetic field. The high-frequency electromagnetic field induces eddy currents in the corresponding current collector element 314, generating a thermal pulse that is emitted by the current collector element 314. The thermal impulses cause welding of the lower zones of walls 101, 102 to each other to form welds of lower zones, for example, welds of bottom folds of bags 100.

The jaws 31 of the welding station 30 of the lower zones are made with such a configuration, for example, have such a length (L) corresponding to the width of the packages, for example, when viewed along the trajectory (T), that the entire unconnected zone of the bottom fold of the package 100 is welded in one cycle by means of work sponges 31.

The lower zone welding jaw 31 is cooled by the cooling device 34 of the lower zone welding station 30 and includes two cooling channels 318, for example, one inlet channel for directing coolant to the jaw 31 and one outlet channel for directing coolant from the jaw 31. The cooling device 34 contains stationary an installed pumping and heat exchange system that is connected to the cooling channels 318, and the cooling device 34 is configured to provide continuous circulation of a coolant, for example water, through the cooling channels 318, for example, during the entire pulse welding cycle.

The frequency of the electric current supplied to the inductors 115, 125, 215, 225, 315, 325 is from 100 kHz to 1 MHz, for example, from 250 kHz to 750 kHz.

The amount of electric current supplied to inductors 115, 125, 215, 225, 315, 325 ranges from 20 A to 600 A.

Electric current is supplied to inductors 115, 125, 215, 225, 315, 325 at a voltage ranging from 40 V to 500 V.

Each welding station 10, 20, 30 is configured to provide a heat sealing pulse through its current collector 114, 124, 214, 224, 314, 324.

The heat sealable film material is preferably a metal free film material, eg a single polymer film having multiple layers that are composed of polyethylene (PE), eg low density polyethylene (LDPE).

The film material preferably does not contain any metal layer. However, the film material may include a non-metallic barrier layer, such as an ethylene vinyl alcohol (EVOH) layer as an oxygen barrier. For example, the EVOH layer is provided as an intermediate layer between the outer and inner polyethylene (PE) layers.

The fixture 150 is preferably molded from the same type of polymer as the polymer of the walls 101, 102 of the bag 100 to improve recycling, for example, molded from a polyethylene (PE) material, such as low density polyethylene (LDPE).

The difference between the temperature of the heat pulse and the sealing temperature, for example, the melting temperature of the heat sealing film material and/or fixture 150, is referred to as delta T or delta temperature. Delta T is preferably less than 200°C, preferably less than 100°C, for example less than 50°C.

In a practical embodiment, with walls 101, 102 formed from low-density polyethylene (LDPE) having a melting point of approximately 110°C, the heat pulse temperature is set to less than 300°C, preferably less than 200°C, for example equal to 150°C.

The film material may be pre-printed, whereby, for example, a surface printed pattern is provided, for example, on the side on which the respective sealing jaws 11, 12, 21, 22, 31, 32 come into contact, having current collecting elements 114, 124, 214, 224, 314, 324. As explained, the approach according to the invention does not cause a negative impact on the printed pattern on the film.

In embodiments, the duration of the thermal pulse is from 10 to 1000 milliseconds, such as from 20 to 500 milliseconds, such as from 75 to 400 milliseconds. The welding stations 10, 20, 30 may vary in the duration of the thermal pulse, as explained herein.

The cycle includes a clamping cooling phase immediately following the thermal pulse phase, during which the jaws 11, 12, 21, 22, 31, 32 are held in the clamping position during said clamping cooling phase. In practical embodiments, the clamping position cooling step may have a duration of from 200 to 800 milliseconds, for example from 300 to 600 milliseconds. The welding stations 10, 20, 30 may vary in the duration of the cooling phase in the clamping position, as explained herein.

In the welding system 1, for each of the welding stations 10, 20, 30, the duration of the heat pulse and the duration of the cooling phase at the clamping position can be set independently.

FIG. 11 shows a schematic view of the welding system 1 shown in FIG. 1 and described above, with the punching station and trimming station excluded.

The welding system 1 includes a control unit 6, which interacts with the welding stations 10, 20, 30, for example, is electrically connected to the welding stations 10, 20, 30. The control unit 6 is configured to control the heat sealing independently for each of the welding stations 10, 20, 30 by means of at least one current-receiving element 114, 124, 214, 224, 314, 324, for example, to regulate the magnitude and/or duration of the heat pulse . In addition, the control unit 6 is configured to control the drive device 13, 23, 33 independently for each of the welding stations 10, 20, 30 to ensure movement of the first jaws 11, 21, 31 and the second jaws 12, 22, 32 relative to each other between opening position and clamping position to regulate the duration of the clamping, for example, to regulate the duration of cooling in the clamping position.

The control unit 6 in the welding system 1 is configured to regulate pulse heating and/or cooling for each of the welding stations 10, 20, 30, which allows precise control of the temperature profile during the pulse welding cycle and which can lead to reliable and repeatable welding the seam formed by each of the welding stations 10, 20, 30. Each parameter of each welding station 10, 20, 30, for example, the current supplied to the inductor to generate the heat sealing pulse, the duration of the heat sealing pulse, the coolant temperature, the cooling rate, the cooling duration at the clamping position, the clamping force, the clamping duration and/or the duration the reverse movement of the jaws 11, 12, 21, 22, 31, 32 can be adjusted separately and independently of the speed at which the superimposed walls 101, 102 of heat-sealable film material move along the welding stations 10, 20, 30, and independently of total cycle duration, which represents a full pulse welding cycle.

The control unit 6 interacts with the drive device 13, 23, 33 of each welding station 10, 20, 30 and is configured to control the drive device 13, 23, 33 independently for each of the welding stations 10, 20, 30 to hold the first jaws 11, 21 , 31 and second jaws 12, 22, 32 in the opening position and/or clamping position for a certain predetermined period of time.

In addition, the control unit 6 is configured to control the drive device 13, 23, 33 independently for each of the welding stations 10, 20, 30 to apply a given clamping force between the first jaws 11, 21, 31 and the second jaws 12, 22, 32. clamp position. The control unit 6 is configured to independently determine for each of the welding stations 10, 20, 30 the clamping force at which the jaws should be held in the clamping position. For one of the welding stations, a given clamping force setpoint may be greater than for another of the welding stations, which means that flexibility in welding many different types of packages 100 is increased.

The control unit 6 interacts with each cooling device 14, 24, 34 and is configured to regulate cooling independently for each of the welding stations 10, 20, 30 through its cooling device 14, 24, 34.

Each welding station 10, 20, 30 contains a temperature sensor in its first jaw 11, 21, 31 and its second jaw 12, 22, 32, which is connected to the control unit 6 and is configured to measure the actual temperature and output data on the actual temperature of the corresponding jaws 11, 12, 21, 22, 31, 32. The control unit 6 is configured to regulate heating and/or cooling based on the output signal of the temperature sensors. The temperature sensors are configured to output the maximum temperature values of the jaws 11, 12, 21, 22, 31, 32, showing, for example, the maximum temperature of the jaws for each of the pulse welding cycles. The control unit 6 is configured to increase the amount of heat input through the corresponding current-receiving element of the sponge 11, 12, 21, 22, 31, 32 when it is detected that the temperature of the sponge is below a predetermined temperature level, or to reduce the amount of heat input when the temperature of the sponge is too high .

The control unit 6 is configured to regulate the temperature and flow rate of the coolant circulating along the corresponding jaws 11, 12, 21, 22, 31, 32, for example, based on the output signal of temperature sensors provided in the jaws 11, 12, 21, 22, 31 , 32. By adjusting the temperature and flow rate, the control unit 6 can adjust the cooling capacity of the cooling devices 14, 24, 34, for example, to provide a cooling profile that is optimally suited to the type of weld to be formed.

Each cooling device 14, 24, 34 includes a coolant temperature sensor for measuring and reporting the actual coolant temperature in the cooling device 14, 24, 34, and includes a coolant flow sensor for measuring and reporting the flow rate. coolant in the cooling device 14, 24, 34. The control unit 6 is connected to these coolant temperature sensors and coolant flow sensors and, in addition, is configured to regulate the temperature and flow rate of the coolant circulating along the respective jaws 11, 12, 21, 22, 31, 32, depending on the output signal of the coolant temperature sensors and coolant flow sensors. The control unit 6 is configured to make a decision to reduce the temperature of the coolant that is pumped towards the corresponding sponge, or to increase the flow rate of the coolant supplied to the corresponding sponge, upon detecting that the temperature of the coolant exceeds a predetermined temperature level.

The control unit 6 interacts with the source 16, 26, 36 of electric current provided at each welding station 10, 20, 30, and is configured to regulate the current supplied to the inductor 115, 215, 315, independently and separately for each of the stations 10, 20, 30 welding, for example, depending on the output signal of temperature sensors in the jaws 11, 12, 21, 22, 31, 32. Regulation of the operation of electric current sources 16, 26, 36 may include regulation of the current value, duration of current supply and/or frequency of the current to regulate the electromagnetic field created by the corresponding inductor 115, 215, 315, whereby the induced eddy currents and thermal impulse from the corresponding current collecting element 114, 214, 314 are controlled.

The control unit 6 can be configured to control the high-frequency current sources 16, 26, 36, taking into account the preheating of the jaws 11, 12, 21, 22, 31, 32. The control unit 6 is configured to regulate the preheating by means of the current-receiving elements 114, 214, 314 before the jaws 11, 12, 21, 22, 31, 32 are moved to the clamping position, and/or preheat control by the current collector elements 114, 214, 314, when the jaws 11, 12, 21, 22, 31, 32 are in clamping position.

The control unit 6 interacts with the movement device 15, 25, 35 provided at each welding station 10, 20, 30, and is configured to control the movement device 15, 25, 35 independently for each of the stations 10, 20, 30 welding to ensure that the first jaws 11, 21, 31 and the second jaws 12, 22, 32 move in synchronization with the continuously moving walls 101, 102. This independent control of each movement device 15, 25, 35 allows each set of jaws 11, 12 to move , 21, 22, 31, 32 of each corresponding welding station 10, 20, 30 together with the walls 101, 102 at different stroke lengths.

The control unit 6 is configured to control the movement device 15 provided in the first welding station 10, the movement device 25 provided in the second welding station 20, and the movement device 35 provided in the third welding station 30 to adjust the position of the first jaws 11 and second jaw 12 of the first welding station 10 relative to the position of the first jaw 21 and second jaw 22 of the second welding station 20 and/or relative to the position of the first jaw 31 and second jaw 32 of the third welding station 30 to regulate the distance between them along a straight path (T) .

Each welding station 10, 20, 30 contains a position sensor, for example an optical position sensor, in its first jaw 11, 21, 31 and its second jaw 12, 22, 32, which is connected to the control unit 6 and is configured to determine the position of the corresponding jaws 11, 12, 21, 22, 31, 32 and outputting data on the position of the corresponding jaw 11, 12, 21, 22, 31, 32, for example, relative to the fixed base and relative to the walls 101, 102 of the heat-sealable film material. The control unit 6 is configured to control devices 15, 25, 35 to ensure movement based on the output signal of the position sensors.

The control unit 6 interacts with the electric motor 62 of the film driving station 60 and is configured to control the driving of the electric motor 62 to initiate or stop the rotation of these one or more film driving rollers 61 and to regulate the speed at which the rollers 61 are driven into rotation by the electric motor 62, for example, to regulate the pulling force that acts on the walls 101, 102 of the film material, and unwinding the roll of film material at the station 40 for handling the rolls.

The control unit 6 is connected to the drive device 73 of the cutting station 70 and is configured to control the movement of the cutting knives 71, 72 by means of the drive device 73 to control the cutting of the walls 101, 102 of the film material to obtain separated individual packages 100.

In addition, the control unit 6 is connected to the movement device 75 provided on the cutting station 70, and is configured to control the movement device 75 to cause the knives 71, 72 of the cutting station 70 to move synchronously with the continuously moving packages 100. The movement control on The cutting station 70 may be separate to match the speed of the moving packages 100, allowing multiple different types of packages 100 to be cut through the same cutting station 70.

The control unit 6 is configured to be controlled by a feedback control mechanism so that the values measured during the first pulse welding cycle form the basis for regulating the pulse heating, cooling and movement of the jaws 11, 12, 21, 22, 31, 32 for subsequent pulse welding cycles. Through this, parameters measured during earlier pulse welding cycles are used as a basis for controlling later pulse welding cycles.

In addition, the control unit 6 is configured to record welding parameters, for example, one or more actual settings for pulse heating, cooling or moving the jaws 11, 12, 21, 22, 31, 32. By recording the welding parameters, it can subsequently be possible to finding out which weld, for example which package 100, was made at which specific settings.

The control unit 6 is provided with a memory 7 in which, for a variety of different weld configurations, for example, for a variety of different types of packages 100, a corresponding set of data is stored displaying settings for the current collector elements 114, 214, 314 heated by electrical sources 16, 26, 36 current, for cooling devices 14, 24, 34, for driving devices 23, 23, 33, 73 and for devices 15, 25, 35, 75 to ensure movement. For each of the different weld configurations, the data set contains a certain profile of parameters for each welding station 10, 20, 30. Parameters include welding temperature, heating rate and heating duration for each susceptor element 114, 214, 314, cooling temperature, cooling rate and cooling duration for each cooling device 14, 24, 34, clamping force, clamping duration and cutting operation data for each drive device 13, 23, 33, 73 and acceleration, speed, initial positions, stop positions and duration of reverse movement of jaws 11, 12, 21, 22, 31, 32 or knives 71, 72 for each device 15, 25, 35, 75 to ensure movement.

The welding system 1 further includes a touch screen 8 configured to display the selected weld configuration in a graphical form, for example, in the form of a graphic image or graphics/graph or graphs showing dimensions and temperatures. The touch screen display 8 allows the machine operator to view relevant parameters and can conveniently check whether the welding system 1 is configured correctly, for example to provide a correct weld configuration.

In addition, the touch screen 8 allows the machine operator to select a weld configuration, for example, a package type, wherein the control unit 6 is configured to select the appropriate data set accordingly once the weld configuration is selected by the operator. This contributes to the flexibility of the welding system 1 and allows for convenient switching between parameters for many different types of packages 100, which all have different parameters for pulse heating, cooling, driving devices 13, 23, 33, 73 and devices 15, 25, 35, 75 to provide movements and which are all to be welded by the same welding system 1, and no complex modifications to the welding system 1 are required. There is no need to change jaws 11, 12, 21, 22, 31, 32 when switching between different weld configurations, since all parameters are set/adjusted automatically via control unit 6.

In FIG. 12, pulse welding of the upper edge regions of the first stack wall 101 and the second stack wall 102 is shown schematically through steps (a) to (e).

In the illustrated embodiment, the welding station 200 includes a first jaw 210 and a second jaw 220. During the production of bags, the walls 101, 102 of the bags continuously move along a straight path (T) from left to right in FIG. 12, for example, at a constant speed. For example, in practice, a continuous tape having two opposite walls of a heat-sealable film material, for example, with a bottom fold, moves under the action of a pulling force along a straight path between the jaws 210, 220 of the sealing device. Consequently, the walls 101, 102 of the package to be manufactured are still connected to the walls of adjacent packages, for example, in the form of a strip of packages still connected to each other.

The welding station 200 is configured to allow movement along with the stack walls 101, 102 along a straight path (T) at least during the welding cycle, for example, when the walls 101, 102 are clamped between the jaws 210, 220.

The cycle begins at step (a), shown on the left side of Fig. 12. The first jaw 210 and the second jaw 220 are initially in a position in which they are spaced from the stack walls 101, 102, which may be "retracted" to some extent in the upper region.

When the first drive device 201 is actuated, the first jaw 210 moves toward its clamping position and the first jaw 210 comes into contact with the first pouch wall 101. Likewise, the second jaw 220 is moved toward its clamping position by the second drive device 202, causing the second jaw 220 to contact the second pouch wall 102. At their respective clamping positions, the first pouch wall 101 and the second pouch wall 102 are lightly pressed against each other at a seam to be formed along the top edge. The clamp is weak because no pressure is applied during the welding process.

Next, during step (b), the jaws 210, 220 remain in their respective clamping positions and move with the pouch walls 101, 102. Step (b) is a pulse welding step during which an electromagnetic field is generated in the first inductor 211 and in the second inductor 221 to generate corresponding thermal pulses in the first susceptor 212 and in the second susceptor 222.

Under the influence of thermal impulses, the first stack wall 101 and the second stack wall 102 are locally fused to each other along the seam to weld the stack walls 101, 102 to each other.

During step (c), thermal pulses are no longer generated since power is no longer supplied to the inductors, but the jaws 210, 220 remain in their clamping positions. Cooling fluid is circulated through channels 214 in jaws 210, 220. This supply of cooling fluid can continue throughout all steps (a)-(e) of the process. Accordingly, heat is also removed from the sealed package 100.

During step (d), the first jaw 210 and the second jaw 220 are moved away from each other to an open position. The sealed package 100 may, as such, be picked up by an additional handling device to allow further processing, such as packaging. After moving the jaws away from each other, the jaws 210, 220 will again be spaced apart.

Finally, during step (e), the first jaw 210 and the second jaw 220 are moved back towards their original position. This movement may occur in a direction opposite to the direction of the straight path (T) to ensure that the jaws 210, 220 are placed in their original positions similar to their positions at the beginning of step (a).

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

It should be understood that the path of movement of the jaws 210, 220 can be any suitable shape, such as round, oval, straight, etc.

For example, the jaws 210, 220 are mounted on a reciprocating support that reciprocates in a direction parallel to the conveying direction. The circulation of coolant along the jaws can be ensured by means of flexible hoses.

13 shows that the jaw 11 of the fixture welding station 10 includes an inductor 115 with one pair of elongated inductor portions 115a, b that are parallel to each other and separated from each other in the vertical direction by a horizontal slot 115c. These two parts of the inductor are located near the rear side of the current collecting element 114.

In an embodiment, the elongated inductor portions 115a, b are made of metal, such as copper.

13 shows that the at least one elongated inductor portion 115a, b is a solid inductor portion made of metal or other material, preferably with high conductivity, for example, preferably made of copper. This design avoids excessive changes in current density in the inductor part and thus unwanted changes in the generated field, for example, unlike the inductor part, which is hollow inside.

13 shows that the at least one elongated inductor portion 115a, b has a constant cross-section, preferably a solid cross-section, along its length along the shaped front surface of the corresponding jaw 11. This design avoids excessive changes in current density in the inductor portion, which otherwise they could occur in places where the cross-section changes, and thereby avoid unwanted changes in the generated field.

Figure 13 shows that the elongated portion 115a, b of the inductor with a constant cross-section has, when viewed from a top view of the jaw 11, a shape corresponding to the shaped front surface of the jaw, and ensures that a constant distance is maintained between the current collector element 114 and the elongated inductor portion 115a, b . This design increases the uniformity of heat dissipation in the current-receiving element.

In alternative embodiments, the inductor may have a variable cross-section, for example, it may be locally sectioned with a width that is less than the nominal cross-sectional width to locally increase the high-frequency electric current density to locally increase the magnitude of the thermal impulse emitted by the current-collecting element.

In embodiments, the distance between the inductor and the current collecting element at a certain location may differ from a constant, for example, the nominal distance between the inductor and the current collecting element. At a smaller distance at a certain location, for example, the electromagnetic field in the pantograph is locally amplified to locally increase the magnitude of the thermal impulse emitted by the pantograph element.

The horizontal slot in FIG. 13 may be an air gap or a slot filled with electrical insulating material.

In embodiments, said gap 115c between adjacent inductor parts 115a, b, which are located one above the other, has a height of 0.01 to 5 mm, more preferably 0.1 to 2 mm.

The presence of a gap 115c between the parallel elongated inductor portions 115a, b allows the field generated by the jaw inductor to be concentrated in the current collector 114 in a desired manner. This is illustrated in FIGS. 16A, B and C.

16B illustrates the field strength and distribution as viewed from above the front side of the jaw, with the field designated Fld and shown relative to inductor 115 and pantograph 114.

FIG. 16C illustrates the field strength and distribution of FIG. 16B in perspective view.

As explained herein, the field is fairly uniform, which improves the uniformity of the pulsed heating of the current collector 114 and thereby improves the quality and reliability of the welding process. In particular, excessive temperature fluctuations to which the film material is exposed and which would otherwise occur if the field were non-uniform are avoided.

13 shows that the current collecting element 114 extends over a horizontal slot 115c existing between the parallel inductor portions 115a, b as viewed from a view of the front surface 111 of the jaw 11.

13 shows that the current collecting element 114 extends over the gap 115c existing between the parallel elongated inductor portions 115a, b as viewed from a view of the front surface 111 of the jaw 11, and overlaps each of the parallel inductor portions 115a, b in that view.

13 shows that the current collecting element 114 is made in the form of a single strip, which extends over the slot 115c existing between the parallel elongated inductor parts 115a, b, and overlaps each of the parallel inductor parts 115a, b in the indicated view.

13 shows that the strip-shaped current collector 114 has an upper edge and a lower edge defining the height of the strip, the height of the strip being at least 50% of the height of one pair of inductor parts 115a, b, including the slot 115c, which are located adjacent to the rear side of the strip one above the other, for example, is from 75% to 125% of the specified height, for example, approximately 100% of the specified height.

13 shows that the strip-shaped current collector 114 has an upper edge and a lower edge defining the height of the strip, and the jaw inductor includes a number, for example, a plurality of inductor parts 115a, b, each of which extends along the rear side current-receiving element. Here, the height of the strip is preferably at most the same as the height of a given number of inductor parts, that is, one or more inductor parts, and the upper edge and the lower edge of the strip preferably do not protrude above and below the one or more inductor parts.

13 shows that the jaw inductor 11 is configured as a pair of adjacent and parallel inductor parts 115a, b adjacent to the rear side of the current collector 114, with current flowing in opposite directions through these inductor parts.

13 shows that the inductor 115 of the jaw 11 includes a C-shaped inductor element having parallel first and second inductor parts connected in series with each other at one end of the inductor defined in the axial direction, for example, by means of a connecting part 115d forming one integral with these parts of the inductor, while the free ends of the inductor parts have terminal clamps for electrical connection with the current source. The connecting portion 115d is preferably located outside the area in which the current collecting element 114 is located, since the connecting portion 115d is likely to exhibit non-uniform field effects that may cause uneven heating of the current collecting element.

13 shows that the inductor 115 of the jaw 11 includes a C-shaped inductor element having parallel first and second inductor parts 115a, b, connected in series with each other and located one above the other, and these inductor parts are separated by a horizontal slot 115c, for example, an air gap or a gap filled with electrical insulating material.

13 shows that the inductor 115 of the jaw 11 includes a plurality of elongated parts, for example, only two elongated inductor parts 115a, b, arranged parallel to each other and located one above the other behind the current collecting element 114.

In an embodiment, the at least one elongated inductor portion 115a, b has a thickness “t” of 1.0 to 4.0 mm, for example 1.5 to 3.0 mm, when viewed in a direction perpendicular to the front surface of the sponge. The limited thickness of the inductor element provides improved cooling of the sponge, including the sponge inductor, since, for example, one or more cooling fluid channels are preferably located near the rear side of the at least one inductor element.

In an embodiment, the at least one elongated inductor portion 115a, b has a rectangular cross-section with a height “h” that is greater than the thickness “t” of the inductor portion. This design allows for limited thickness, allowing for efficient cooling.

14 shows that each jaw may be configured with one or more cooling fluid passages 118, wherein the cooling fluid is, for example, a cooling liquid, such as water, passed through the cooling fluid passages 118, such as , through the use of a pump unit, wherein the coolant circuit is a closed circuit including a heat exchanger configured to remove heat from the coolant.

Preferably, no cooling fluid passes in the area between the inductor 115 and the current collector 114, since this would increase the distance between them excessively and reduce the effectiveness of the pulsed heating caused by the field. It should be understood that given the desirability of placing the current collector element 114 very close to the front surface 111 of the jaw 11, there is in practice no room for any cooling channel in this area. Thus, in practical embodiments, cooling of the sponge 11 is preferably accomplished by using a controlled flow of a cooling fluid, such as a liquid, through one or more passages 118 that are located behind and preferably in close proximity to the inductor portions 115a, b.

In an embodiment, at least one cooling fluid passage 118 extends along the at least one inductor portion 115a,b that extends along the rear side of the current collector element 114.

Preferably, the system 1 is configured such that the cooling of the jaws is carried out during the entire pulse welding cycle, therefore also during the generation of the heat pulse, which occurs so quickly that it is not substantially negatively affected by the cooling. In another configuration, cooling may be interrupted or reduced at the instant of the thermal pulse.

In an embodiment, current collector 114 is made of a metallic material, such as a metal or metal alloy, such as a thin strip of metal.

For example, current collector 114 is made of or contains aluminum, nickel, silver, stainless steel, molybdenum, and/or nickel-chromium alloy, aluminum, nickel, silver, stainless steel, molybdenum, and/or nickel-chromium alloy.

13 shows that the current collector element 114 is configured as a strip having opposing front and rear main surfaces that limit the thickness of the strip therebetween. In an embodiment, the thickness of the current collector element 114 is constant over the entire length of the strip

In embodiments, the thickness of the current collector element may differ in a certain location from the nominal thickness. For example, the susceptor element may have a thick portion adjacent its rear surface, for example, facing away from the front surface of the jaw, to locally increase the electromagnetic field strength in the susceptor element to locally increase the magnitude of the thermal impulse that is emitted by the susceptor element.

13 shows that the current collecting element 114 is made in the form of a flat strip, and it is most preferable if the jaw has one current collecting element in the form of a flat strip. This flat strip design is particularly preferred for processing plastic fixtures that have an attachment portion with flat and preferably smooth surfaces for welding.

13 shows that the current collecting element 114 is a strip, for example made of metal, for example aluminum, the height of the strip being from 3 to 10 millimeters, for example from 4 to 8 millimeters. Figure 13 shows that the strip has a constant height along its entire length.

In an alternative embodiment, the height of the current collecting element may not be constant. For example, the bottom edge of a current collector in a fixture welding station jaw may be curved upward at a central portion, such as a portion that is configured to abut the attachment portion of the fixture during use, to provide less heat transfer to the bottom edge of the attachment portion and the air below it. . This increases the rate at which the weld can be cooled, since air would otherwise act as an insulator, reducing the cooling rate, for example.

13 shows that the strip-shaped current collector element 114 has no holes along its length.

Figure 13 shows that the jaw 11 is provided with one continuous current-receiving element 114, made in the form of a strip, for example, of metal.

13 shows that the current collector element 114, for example in the form of a strip, has a thickness of 0.01 to 5 mm, preferably 0.05 to 2 mm, more preferably 0.08 to 0.8 mm, for example, from 0.08 to 0.5 mm. As a rule, it is considered desirable to have a minimum thickness of the current-collecting element, taking into account the desire to quickly cool the sponge, which includes the inductor and the current collector, after the end of the thermal pulse. The design of the pantograph with low thickness helps to achieve this goal. It should be noted that, unlike the pulse welder mentioned in the introduction, no electrical current from the current source passes through the current collector, so there is no need to design the cross-section to handle such current flow.

13 shows that the jaw 11 is provided with one continuous current-receiving element 114 made in the form of a strip, for example of metal, having a strip height of 3 to 10 mm, for example 4 to 8 mm, and a thickness of 0 .08 to 0.8 mm, for example from 0.08 to 0.5 mm. The strip is made, for example, of aluminum material.

13 and 16A-C show that the jaw 11 is designed in such a way that the high-frequency electromagnetic field generated by the inductor 115 mainly causes very rapid heat generation in the front surface layer of the current collector element 114 due to the so-called skin effect. Skin effect is the tendency for alternating electric current to be distributed in a conductor such that the current density is greatest near the surface of the conductor and decreases exponentially at greater depths in the conductor. At high frequencies, the depth of the skin effect becomes smaller. This depth can be, for example, 0.15 mm for an aluminum current collector element if the field frequency is 350 kHz. It is envisaged that the thickness of the current collector element exceeds this skin depth, but not to an excessive extent for the reasons stated herein.

13 shows that the minimum distance between the rear side of the current collector 114 and the adjacent inductor parts 115a, b is 0.025 mm or 0.05 mm or 0.1 mm and the maximum distance between them is 3.0 mm or 2.0 mm, or 1.0 mm. The minimum values of this distance are provided primarily with a view to ensuring the possibility of effective electrical insulation between the inductor part(s), on the one hand, and the current-receiving element, on the other hand. In embodiments, this gap is provided to be filled only with electrical insulating material. The maximum value of this distance is provided primarily in view of the presence of part(s) of the inductor in close proximity to the rear side of the current collecting element, with a preferred maximum distance of 1.0 mm. In a practical embodiment, this distance may be 0.05 mm. Thus, in a practical embodiment, this distance may be less than the thickness of the current collecting element itself.

The entire gap between the rear side of the current collecting element and the adjacent portion(s) of the inductor is preferably filled with electrically insulating material.

14 illustrates that the gap between the rear side of the current collector 114 and the adjacent portion of the inductor 115 is filled with one or more layers of electrical insulating tape, for example, at least a layer 119a of Kapton ( polyimide film tape ) and a layer 119b of Teflon, for example , only one layer of Kapton tape and one layer of Teflon tape.

In an embodiment, the electrical insulation between the rear side of the current collector and the adjacent inductor portion(s) has a thickness ranging between a minimum value of 0.025 or 0.050 or 0.1 mm and a maximum value of at most 3. 0 mm or 2.0 mm.

In an embodiment, the anti-adhesive layer 119c on the front side of the sponge 11 is formed as a layer of Teflon tape. In another embodiment, the release layer may comprise glass or the like.

14 illustrates that the front surface of the current collector 114 is coated with at least one layer of electrically insulating material 119d, for example Kapton, for example Kapton tape, for example having a thickness of 0.01 to 0.05 mm, for example , approximately 0.025 mm.

In an embodiment, the distance between the front surface of the jaw and the current collecting element is a minimum of 0.025 mm or 0.050 mm and a maximum of 2.0 mm or 1.0 mm or 0.5 mm. In this case, the minimum distance may be determined by the presence of the anti-adhesive layer 119c. The anti-adhesive layer can be applied in the form of a coating, for example a glass or Teflon coating, on a sponge, for example on a current collecting element.

In an embodiment, the distance between the front surface of the jaw and the current collecting element is filled with at least one layer, for example, a plurality of layers of electrically insulating material, such as tape, for example, at least a layer 119d of Kapton tape and a layer 119c of Teflon tape as a release agent. layer forming the front surface of the sponge, for example, with only one layer of Kapton tape and one layer of Teflon tape.

13 shows that the shaped front surface of the jaw 11 is smooth in the area of contact with the film material walls 101, 102, so that there is no relief feature that would cause the film material to be locally held away from the front surface, so that missing, for example, one or more ribs, one or more projections, etc. This design is preferred in combination with the smooth design of the welding surfaces of the attachment portion 151. The smooth contact area of the front surface of the jaws is preferably configured to be parallel to the welding surface of the attachment portion 151 that is to be attached to the film material walls.

13 shows that the jaws 11 are configured, for example, of such a length, that the entire unconnected edge region into which the pouring element 150 is inserted, for example by the insertion element 93 of the system 1, is welded in one cycle. when working with sponges. In this way, both the pourer element 150 is secured in the edge zone and the entire edge zone is welded to close it. This avoids the need for additional welding operations along said edge zone.

13 shows that the recessed portion of the surface of each jaw 11 is curved throughout its entire length in the longitudinal direction. In another, more preferred embodiment, the recessed surface portion is adapted to a diamond-shaped attachment portion of the device. In this case, the buried surface area is formed by a central curved zone located between two straight zones. This design allows for improved tight contact between the front surface of the jaw and the film wall and fixture.

Both jaws 11 are shown to have a main body 11a, for example made of plastic or ceramic material, for example a heat-resistant material, for example polyetheretherketone (PEEK), on which a current collecting element and an inductor are mounted. The plastic or ceramic material is selected so that it does not negatively affect the field generated by the inductor, or at least not in an undesirable manner. Boron nitride, aluminum nitride, polyphenylene sulfide (PPS) and/or vulcanized silicone materials may also be considered as main body materials. In particular, boron nitride can provide good thermal conductivity, thereby allowing good heat transfer from the current collecting element to a cooling device, such as a cooling fluid.

One or more cooling channels 118 are formed, for example machined, in a jaw main body made of, for example, PEEK.

For example, one or both jaws 11 have a main body 11a having a front side of the main body on which one or more grooves are formed in which the one or more inductor parts are disposed. In embodiments, the current collecting element is located on top of the front side of the main body, as discussed herein in connection with these one or more parts of the inductor. Here, one or more layers of electrically insulating material, such as Kapton or Teflon, are located between the inductor portion(s) and the current collecting elements. One or more additional layers of electrical insulating material, as well as an outer anti-adhesive coating, are secured over the current-receiving element from the front surface of the jaw.

15 illustrates the jaw 31 of the bottom zone welding station 30 used in the case of a package 100 with one or more side folds, where the edge zone in which the weld is to be formed may include a so-called triple point. In such a situation, it may be preferable to provide an elastic support layer 319e, for example of vulcanized silicone rubber and/or Teflon, behind the current collector element 314, thereby allowing the front side of the jaw to adapt to a local change in the number of walls of the film material. For example, the elastic layer 319e has a thickness of from 0.1 to 2.0 millimeters. In this case, it should be understood that the thin current collector element 314 can be flexed to adapt to a local change in the number of walls.

Claims (40)

1. Sealing system (1) for heat sealing of heat sealable film material, the welding system contains: - a loading section comprising a roll handling station (40) which is configured to receive one or more rolls of heat sealable film material, said loading section being configured to dispense superimposed walls (101, 102) of heat sealable film material, unwound from one or more rolls; - a welding section (10, 20, 30), located downstream of the loading section and containing two or more welding stations located sequentially along a straight path (T) for superimposed walls protruding from the loading section; - a station (60) for driving the film material, located along the straight path and passing through the welding section, wherein the station for driving the film material is configured to ensure the movement of superimposed walls of heat-sealable film material at a constant speed under the action of the pulling force forces along a straight path beyond the welding station; Moreover, each welding station contains: - a welding device containing a first jaw (11, 11’, 21, 21’, 31, 31’, 210) and a second jaw (12, 12’, 22, 22’, 32, 32’, 220); - a drive device (201, 202), which is configured to allow the first and second jaws to move relative to each other between the opening position and the clamping position; wherein the first jaw has a first front surface (111, 211, 311) configured to contact a corresponding first wall of heat sealable material, and the second jaw has a second front surface configured to contact a corresponding second wall of heat sealable material, wherein at least the first jaw contains a heated element for heat sealing a certain area of the superimposed walls of the heat sealable film material when they are sandwiched between the first and second jaws; - a device (15, 25, 35) for providing movement, configured to ensure movement of the first and second jaws synchronously with the superimposed walls when they are clamped between the first and second jaws, in this case, the welding system additionally contains a control unit (6) that interacts with welding stations, characterized in that at least each first jaw of each welding station contains, next to its corresponding front surface, at least one heated element, made in the form of a current-receiving element (114, 214, 314) containing electrically conductive material, while said pulse heated element extends along the corresponding front surfaces, in that for each pair of the first and second jaws of each welding station, at least one of its jaws contains an inductor (115, 215, 315), in that the system contains a source (16, 26, 36) of high-frequency electric current connected to an inductor, in that the system contains at least one cooling device (14, 24, 34), which is configured to continuously cool at least one of the first and second jaws of each welding station, in that each welding station is configured to perform an integrated pulse welding and cooling cycle, wherein a corresponding drive device is actuated to move respective first and second jaws to a clamping position in which the first and second walls are clamped by the first and second jaws, and herein, in the clamping position, the high-frequency electric current source temporarily supplies a high-frequency electric current to the inductor, whereby the inductor creates a high-frequency electromagnetic field, and the high-frequency electromagnetic field induces eddy currents in the current collecting element, creating a thermal pulse emitted by the current collecting element, and the said thermal pulse has a certain duration thermal pulse and ensures welding of this zone of the first and second walls, welded to each other, or welding of this zone of the first and second walls to the device, if any, and after the end of the supply of high-frequency electric current to the inductor, this at least one of the first and second jaws , as well as the welded area are effectively cooled by the cooling device during the cooling time in the clamping position while the respective first and second jaws remain in the clamping position, and wherein the driving device is driven to move the first and second jaws to the opening position after expiration cooling time in clamping position, in that the control unit is configured - independently for each of the welding stations - to control the supply of high-frequency electric current to the inductor and, thereby, to regulate the thermal pulse emitted by the current-receiving element, and in that the control unit is configured - independently for each of the welding stations - to control the drive device to move the first and second jaws relative to each other between the opening position and the clamping position, which makes it possible to regulate the time the first and second jaws remain in the clamping position and, thereby reducing the cooling time in the clamping position. 2. The welding system according to claim 1, wherein the control unit, together with the one or more cooling devices, is configured to regulate the cooling rate of at least one of the first and second jaws, as well as the zone that is welded by the welding station, independently for each from welding stations. 3. The welding system according to claim 1 or 2, wherein each of the welding station jaws comprises a current-receiving element containing an electrically conductive material, as well as a corresponding inductor. 4. The welding system according to any one or more of the preceding claims, wherein the current collector element extends along the front surface of the corresponding jaw and has a rear side, and wherein each inductor includes an elongated inductor portion (115a, 115b) that extends adjacent the rear side of the corresponding current-receiving element. 5. The welding system according to any one or more of the preceding claims, wherein the jaw inductor comprises a plurality of elongated inductor parts parallel to each other, and wherein adjacent inductor parts are separated from each other by a slot (115c) and the current collector element extends over these one or more cracks when looking at the front surface of the sponge. 6. The welding system according to any one or more of the preceding paragraphs, wherein for each of the welding stations the cooling device is configured to provide continuous circulation of liquid coolant through one or more cooling channels (118, 218, 318) located in the first jaw and/ or in the second sponge. 7. The welding system according to any one or more of the preceding claims, wherein the loading section comprises a folding station (50) which is configured to fold the film material dispensed from a single roll into two superimposed walls. 8. The welding system according to any one or more of the preceding claims, wherein the control unit is configured to control the movement device to cause the first and second jaws to move in synchronization with the superimposed walls when they are clamped between the first and second jaws, independently for each welding station. 9. The welding system according to any one or more of the preceding paragraphs, wherein the welding system comprises a fixed frame (2), and wherein devices for providing movement provided at successive welding stations are installed on opposite sides of a straight path along which The stacked walls move through the welding section. 10. The welding system according to any one or more of the preceding claims, wherein the welding section is provided with a trimming station (55), wherein the trimming station comprises: - a trimming device (56) configured to perform, on command, a trimming operation to remove part of the webs superimposed on each other; - a device for providing movement, configured to ensure movement of the trimming device synchronously with the walls superimposed on each other when performing a trimming operation; - a collection system configured to remove cut parts. 11. A technological machine for producing soft bags, wherein each of said bags has walls formed from a heat-sealable film material, wherein the technological machine contains a sealing system according to one or more of claims 1-10. 12. The technological machine according to claim 11, wherein the machine is configured to produce bags having a device, and the first welding station, provided along a straight path, is made in the form of a station (10) for welding devices, configured to weld the device to the walls superimposed on top of each other by heat sealing, and wherein one or more of the downstream welding stations are configured to weld one or more other areas of the stack. 13. The technological machine according to claim 12, wherein the machine comprises a fixture insertion device configured to insert the attachment part (151) of the fixture in an unconnected edge zone between opposite walls, and wherein the fixture welding station is configured to weld the walls to the attachment portion of the fixture by means of heat sealing. 14. The technological machine according to claim 12 or 13, in which the straight path is horizontal, and the loading section is configured to fold the film material dispensed from one roll in the form of two walls superimposed on each other, and the walls superimposed on each other on each other, have a vertical orientation when fed into the welding section in the presence of an unconnected upper edge zone between the opposite walls and a bend/bent area along the lower side of the opposite walls, while the device for inserting devices is configured to insert the attached part of the device in the unconnected upper edge zone between opposite walls, and the movement device provided at the corresponding welding station is installed under the straight path. 15. The processing machine according to any one or more of claims 11-14, wherein the machine includes a cutting station (70), which is located downstream of the film material driving station and is configured to make one or more cuts to create individual packages . 16. A method for heat sealing a heat sealable film material, which uses a sealing system and/or a processing machine for producing bags according to any one or more of claims 1 to 15. 17. The method of claim 16, wherein the film material is a single polymer heat sealable film material formed from polyethylene (PE), wherein the film material does not contain any metal layer. 18. The method according to claim 16 or 17, wherein bags having a fixture are manufactured, and wherein a first welding station provided along a straight path is configured as a fixture welding station for welding the fixture to one or both of the superimposed walls. , by heat sealing, and wherein one or more of the downstream welding stations are configured to weld one or more other areas of the stack. 19. The method according to any one or more of claims 16 to 18, wherein the film material is printed on the side contacted by a corresponding jaw of at least one of the sealing stations having a pulse heated element.