WO2019174803A1

WO2019174803A1 - Apparatus for sealing a packaging

Info

Publication number: WO2019174803A1
Application number: PCT/EP2019/051748
Authority: WO
Inventors: Ulrich Wieduwilt; Marcel Egli; Johannes Gabriel GROSSE; Christoph LANGOHR
Original assignee: Robert Bosch Gmbh
Priority date: 2018-03-14
Filing date: 2019-01-24
Publication date: 2019-09-19
Also published as: DE102018203904A1

Abstract

The present invention relates to an apparatus for sealing a packaging material (10), comprising at least one sealing device (20) having at least one sealing jaw (26) and at least one counter-holder (31) which are designed to be movable relative to one another, wherein the sealing device (20) comprises at least one coil (25) having a coil core (24) for generating a magnetic field which, for sealing, passes through the packaging material (10) to be sealed, wherein at least one magnetic field-conducting element (28) is provided which at least partially surrounds the coil (25) in order to conduct the magnetic field of the coil (25) to the packaging material (10) to be sealed.

Description

description

title

Device for sealing a packaging

State of the art

The present invention relates to a device for sealing a package according to the preamble of the independent claim.

A generic device is known for example from WO 2002/060759. This device comprises a coil which can be connected to a high-frequency current source and whose core consists of a ferromagnetically conductive material. The core has two shafts with an air gap. The spool is wound around a bow portion connecting the shafts, passing through

Metal strip is formed with a certain geometry.

From US 2005/0133496 A1 is already a heat-sealing device for

Packaging material known. Here, the field lines of a magnetic field generated by a coil are passed through the packaging material at two different locations. For this purpose, a substantially U-shaped structure is provided, around the central part of which a coil is wound whose magnetic field is conducted to the film at different locations via two ferromagnetic bars.

The invention has for its object to further improve the quality of the sealed seam. This object is solved by the features of the independent claim.

Disclosure of the invention

The device according to the invention according to the features of the independent claim has the advantage that the quality of the sealed seam is improved. This is achieved by a magnetic field leading element for targeted guidance of the magnetic field to be sealed to the packaging material is provided. Furthermore, the coil for generating a for the

Induction sealing magnetic field used so arranged that the

Magnetic field to be sealed packaging material only at least one

penetrates desired location. This is done by an appropriate

Embodiment of the magnetic field leading element achieved. In this way, in particular a stable transverse seal can be achieved. Here, the magnetic field leading element at least partially surrounds the coil. This allows a particularly safe and reliable shielding and thus

Magnetic field guide can be achieved.

In an expedient development, at least one field-guiding element for influencing the magnetic field is provided, wherein the field-guiding element is configured such that the packaging material to be sealed can be arranged between the coil and the field-guiding element. In this way, the magnetic field can be directed in a targeted manner through the packaging material, in particular at those points where, for example in the case of overlapping seams, a high heat input or field line entry is necessary for reliable sealing.

In an expedient development, at least one sealing profile is provided. Here, the sealing profile is connected to the magnetic field leading element and / or the coil core and / or the field-guiding element. The sealing profile can be arranged between the magnetic field leading element and the packaging material. Alternatively or additionally, a sealing profile can be arranged between the field-guiding element and the packaging material. By means of the sealing profile, the desired contact can be produced in a defined manner during sealing with the packaging material. The sealing profile is preferably made of magnetically non-conductive material and is matched to the desired seal. A suitable choice of material of the sealing profile also ensures that especially in a compound of the sealing profile with both the magnetic field conducting element as well as the coil core, the field lines safely penetrate the packaging material.

In an expedient refinement, the coil and / or the magnetic field-guiding element and / or the field-guiding element are arranged on the sealing jaw or on the counter-holder. This is the way to lead the way

high-frequency induction currents as short as possible and consequently as low loss. In addition, the packaging material between the sealing jaw and the counter-holder is fixed, so that it is at the seal to a particularly narrow Contact and as constant distance ratios with the packaging material to be sealed, so that the quality of the seal further improved. Particularly useful is the magnetic field leading element formed with at least partially U-shaped cross section and surrounds the coil. As a result, the magnetic field can be passed through the packaging material in only a single side in a particularly simple manner. Particularly expediently, the magnetic field guiding element surrounds the coil from five sides and is open towards the packaging material. As a result, the arrangement is particularly reliable and safe shielded.

In an expedient development, the magnetic field-guiding element is connected to the spool core, in particular on a side remote from the packaging material. Thus, the magnetic circuit can be specifically directed over the coil core, the magnetic field leading element through the packaging material to the field-leading element and again through the packaging material back to the spool core.

In an expedient development of the spool core comprises at least one gap, in particular for receiving a release agent. Thus, with this arrangement, two adjacent packaging material tubes can be separated from each other in the transverse seal in one operation. The gap can also be used to separate the bobbin into two magnetic halves, each forming components for two magnetic circuits. About these two magnetic circles can each of the transverse seams of the adjacent

Packaging are created, which are separated during the seal by the release agent.

In an expedient development, the field-leading element

cuboid, preferably rod-shaped, and / or comprises at least one recess and / or at least one bevel or chamfer and / or a plurality of elements. This will further streamline the field line, further enhancing seal quality. The variant of the two field guide elements leads to the reference arrangement (straight version) to a significant homogenization of the heat sources in the transverse seam of the package. The lateral blocks increase the coupling at the edges and in the side fold. The middle block or section increases the coupling in the region of the longitudinal seam. In an expedient development, the magnetic field-guiding element and / or the coil core and / or the field-guiding element consists of a ferrite or of a soft-magnetic material, in particular for high-frequency coils. As a result, the high-frequency magnetic field can be conducted or dissipated as lossless as possible.

In an expedient development, the field-guiding element is arranged on the counter-holder or the sealing jaw. Depending on the application, a plurality of field-guiding elements can also be provided. This enables targeted field guidance in the immediate vicinity of the packaging material. In addition, via an appropriate choice of the geometry of the field-leading

Elements or the field-guiding elements particularly simple adjustments to different types of packaging are made.

In an expedient development, at least two field-leading

Elements provided, in particular at a seam area or at a multi-layer area of the packaging material to be sealed. With that you can

In particular, particularly thick packaging material areas with high

Field line concentration are applied, which contributes to these critical areas to a reliable seal.

In an expedient development, the field-guiding element is firmly connected to the counter-holder or the sealing jaw and / or the field-guiding element can be inserted into the counter-holder or the sealing jaw. Especially with the last variant can be quickly adapted to a flexible

reach different types of packaging. The flexibility of the arrangement increases.

In an expedient development, turns of the coil are in

Essentially formed parallel to the packaging material. The resulting field lines penetrate the packaging material substantially transversely to its

Surface.

In an expedient development, sealing of the packaging material takes place when the sealing jaw or counter-holder is stationary relative to the packaging material. So that can the field line entry or heat input at the desired sealing point of the packaging material can be made particularly reliably.

In an expedient development is at least one more

Sealing device provided for creating a longitudinal seam, in particular a fin seam. Thus, the transverse sealing device can be particularly preferably used in a tubular bag machine.

In an expedient development, the use in one

Packaging machine, in particular provided in a tubular bag machine. Especially for this application, the described

Sealing device.

Further expedient developments emerge from further dependent claims and from the description.

Short description of the drawing

Hereinafter, an embodiment of the invention will be described in detail with reference to the accompanying drawings. In the drawing shows the

FIG. 1 is a perspective view of a packaging machine;

FIG. 2 shows a sealing device of a first exemplary embodiment in FIG

Cross-section,

FIG. 3 shows a sealing device of a further exemplary embodiment for a specific packaging,

FIG. 4 shows a sealing device of a further exemplary embodiment in FIG

Cross section for an alternative packaging,

FIG. 5 shows a sealing device of a further exemplary embodiment in FIG

Cross-section for another packaging with several

Overlapping areas, 6 shows a sealing device of a further exemplary embodiment in cross section for a further alternative packaging,

FIG. 7 shows a perspective view of a sealing device of a further exemplary embodiment without a cutting function,

8 shows the sealing jaw according to the embodiment of FIG. 7 in FIG

Cut,

FIG. 9 shows a perspective view of a sealing device of a further exemplary embodiment with a cutting function,

10 shows a sealing device according to the embodiment of Figure 9 in

Cut,

Figure 1 1 a sealing device with marked field line course of the magnetic field and

Figures 12-15 different embodiments of the field-leading

Elements in a perspective view.

A packaging machine 8 comprises, for example, a packaging material roll on which the packaging material 10 to be processed is rolled up. The packaging machine 8 can be designed, for example, as a tubular bag machine. In the embodiment shown in Figure 1 is a horizontal

Tubular bag machine, in which the products to be packaged 12 are fed horizontally via a feed 14. Alternatively, however, vertical tubular bag machines could also be used, in which the products to be packaged, often free-flowing products, are supplied from above to the packaging material tube. Other packaging machines 8 are conceivable in which sealing devices 18, 20 are provided for sealing a

Packing material 10 to a desired packaging.

The packaging material 10 comes together with the product 12 to a

Forming device 16. The shaping device 16 forms the packaging material 10 into a packaging material tube. The shaping device 16 leads to the two

Packstoffränder 34, 36 of the packaging material 10 together around the product 12 to be packaged. Subsequently, the longitudinal seam is formed in a sealing device 18 by connecting the packaging material edges 34, 36 to one another. For example, the longitudinal seam may be formed as a fin seam. Corresponding feed means 33 are formed, which cover the packaging material edges 34,

36 of the sealing device 18 out. This can be done by appropriate

driven rollers and guides done.

After the sealing device 18 has formed the longitudinal seam of the packaging material tube, this comes with the coated products 12 to a

Sealing device 20, in particular transverse sealing device. The

Cross-sealing device 20 includes a sealing jaw 26 and a counter-holder 31, which are designed to be movable relative to each other. The transverse sealing device 20 forms the transverse seam of the packaging material tube. In the counter-holder 31, a release agent 19 is integrated, which separates the packaging of the packaged products 12 from the endless packaging material tube. After

Cross-sealing device 20 closes one indicated by an arrow

Dispensing device 21 on. The sealing device 20, which is designed in particular as a transverse sealing device, will now be shown in greater detail below.

A first embodiment of a sealing device 20 is shown in FIG. The sealing device 20 comprises at least one coil core 24, around which a coil 25 is wound. The coil core 24 has a rectangular cross-section. One side of the spool core 24 is disposed immediately adjacent to the packaging material 10 to be sealed. At this side of the bobbin 24, the magnetic field exits or penetrates and passes through the packaging material 10 to be sealed to an opposing field-guiding element 29. The opposite side of the bobbin 24 is connected to a magnetic field leading element 28 which is substantially parallel to the Packing material 10 runs. The transverse to the packaging material 10 sides of the coil 25 and the coil core 24 are laterally surrounded by a certain distance from the magnetic field leading elements 28, which pass on the packstofffernen side in the parallel to the packaging material 10 oriented part of the magnetic field leading element 28.

In the exemplary embodiment, the field-guiding element 29 has at least one gap, through which the separating means 19 can be moved to sever the sealed packaging material 10. Accordingly, in the coil core 24 a Recess indicated, in which the release agent 19 can dip to completely cut through the packaging material 10.

Furthermore, magnetic field guiding elements 28 are provided which the

Coil core 24 at least partially surrounded. In the exemplary embodiment, the magnetic field leading elements 28 are U-shaped and surround the coil core 24 from three sides (based on the cross section shown in Figure 2). Only on the side of the spool core 24, which is arranged immediately adjacent to the packaging material 10 and over which the magnetic field is introduced into the packaging material 10, no magnetic field leading element 28 is provided. The magnetic field leading element 28 consists of a magnetically highly conductive material. For example, this is a ferrite element, preferably ferrite plates. The magnetic field leading elements 28 serve to shield the magnetic field or the targeted conduction of the magnetic field lines in the vicinity of the coil 25th

The inductor for generating a magnetic field consists of the coil core 24 and the coil 25. The coil core 24 is preferably a ferrite core. The inductor is used to create the sealing seams, especially in stationary contact. During the sealing process there is no relative movement between inductor (coil core 24 with coil 25) and

Packaging material 10. The inductor is located on one side of the packaging material 10, the field-guiding element 29 on the other side of the packaging material 10.

The coil core 24 and the coil 25 and / or the magnetic field leading elements 28 may be part of a dashed line sealing jaw 26. Sealing jaw 26 and counter-holder 31 can be moved relative to one another in order to contact the packaging material 10 for the purpose of sealing.

The field-guiding element 29 or the field-guiding elements 29 is or are preferably arranged on the counter-holder 31 of the sealing device 20.

In particular, they are inserted on the counter-holder 31. Alternatively, they can also be introduced elsewhere. The cutting function is over

Separating agent 19 also housed in the anvil 31 as indicated by dashed lines. According to FIGS. 3-6, different types of folding of the packaging material 10 are shown in order to form a tubular bag or a corresponding packaging. In particular, the package may have a different width. Accordingly, the field-guiding elements 29 can be particularly preferred to the different packaging forms and position of

Adjust overlapping areas or similar.

The field-guiding element 29 is - based on the packaging material 10 - on the opposite side of the inductor. The field-guiding element 29 is preferably made of ferrite. There may also be several field-guiding elements 29. In particular, it is possible to influence the sealing properties of the packaging material 10 in a targeted manner via the variable choice of the geometry of the field-guiding elements 29. In particular, can on a different number of layers, such as, for example, overlap seams, gussets, folded longitudinal seal fins oa. can result, particularly variable and flexible by corresponding field-leading elements 29 are reacted as is for example in the embodiments according to Figures 3-6 expressed. The shape of the field-guiding element 29 may also vary. For example, a round, angular, rectangular, triangular, corrugated or similar shape of the field-guiding element 29 could be used. The position, the thickness, the position and the number of the field-guiding element 29 can also be adjusted in order to achieve the desired heating for the secure sealing of in particular multi-layered packages.

Also, the distance between the inductor and the field-guiding element 29 and the field-guiding elements 29 can be between or during the

Siegelprozesse be changed. Also the movement profile or the

Movement in the opposite direction of the movement of the packaging material 10 and / or the position and / or the positioning of the field-guiding element 29 can be changed between and during the sealing processes.

With regard to the embodiments according to FIGS 3-5, this is

field guiding element 29 preferably to be arranged where at least one seam 11 or overlap of the packaging material 10 is located. Thus, the magnetic field is guided especially over the seam areas. According to Figure 7, the sealing device 20 extends rectangular. Even if the end face of the sealing jaw 26 is also provided with a magnetic field leading element 28, this element 28 is made transparent for reasons of clarity, in order to make visible the coil 25 located inside the sealing jaw 26. The inside of the sealing jaw 26 extending coil 25 is provided with substantially parallel to the packaging material to be sealed 10 oriented windings, which are wound around the spool core 24. The magnetic field leading elements 28 surround the coil 24 at the selected rectangular shape on five sides. Only the side, which is arranged adjacent to the packaging material 10 to be sealed, is not surrounded by a magnetic field guiding element 28. At least one sealing profile 38 is arranged at this point. In the embodiment, two in the middle separate sealing profiles 38 of the sealing jaw 26 are arranged. The sealing profile 38 is, for example, a 3-bar profile. In principle, the sealing profile 38 can be designed as desired, depending on the desired application. The sealing profile 38 is arranged on the underside of the magnetic field leading element 28 or connected thereto. The sealing profile 38 is also connected to the spool core 24. Here, the sealing profile 38 is to be selected so that does not close at this point, the magnetic circuit.

Alternatively, the sealing profile 38 could be connected only to the spool core 24. Eventually, the sealing profile 38 could not be formed continuously and be formed, for example, in two parts. One part could then be with the

Magnetic field leading element 28, the other part to be connected to the coil core 24.

In a corresponding manner, a sealing profile 39 is also provided on the counter-holder 31 on its surface. In the closed state of the sealing device 20, the sealing profile 39 of the counter-holder 31 interacts with the sealing profile 38 of the sealing jaw 26. The sealing profile 38 is magnetically non-conductive. In this case, the sealing profile 39 may be connected to the field-guiding element 29.

As clearly visible in section according to FIG. 8, the coil core 24 consists of two plates, preferably ferrite plates. Between these two plates, a gap is formed. This gap serves, for example, to receive the door release means 19 in the closed state of the sealing device 20. This arrangement is particularly favorable, in particular from a manufacturing point of view, since Standard plates or standard ferrite plates can be used. The intermediate space is provided either with air or with plastic, as far as this does not hinder the inclusion of the release agent 19.

In FIG. 8, an alternative cross-section of the magnetic field guiding element 28 is also shown in dashed lines. Thus, the magnetic field leading element 28 runs in the direction of the packaging material 10 with a chamfer 30, that is not perpendicular to the surface of the packaging material 10, but with a certain of 90 °

deviating angle. This chamfer 30 on the outer ferrite or parts of the magnetic field leading element 28 leads to a concentration of the electric field. About this adapted geometry by means of the chamfer 30, the

Heating image can be controlled in the packaging material 10.

The embodiment of Figures 9 and 10 differs from

that of Figures 7 and 8 in that now a release agent 19 is provided. When closed, it dives into the gap provided in the spool core 24. By way of example, the separating means 19 with a shaft

connected according to for separating the sealed

Packstoffschlauchs can be moved.

In addition, 9 and 10 field-leading elements 29 are shown in the embodiments of FIGS. The field-guiding elements 29 are located below the sealing profiles 39 of the counter-holder 31. They extend essentially over the width of the sealing profile 39.

In the embodiment according to FIG. 11, the typical

Plotted line curves. In essence, the field lines 44 extend in the spool core 24, via the top connected to the spool core 24

Magnetic field leading element 28 respectively to the outside and along the

spaced and parallel to the outside of the coil 25 extending further magnetic field leading element 28 via a sealing profile 38 through the packaging material 10 through the further sealing profile 39 to the field-leading element 29. From there, the field lines 44 go back over the sealing profiles 39 and 38 back to the spool core 24. The spool core 24 is also connected to the sealing profile 38 at the appropriate locations. Further exemplified are field-free zones 42, in which substantially no magnetic field exists. Therefore, the magnetic field guiding elements 28 are arranged and provided in the manner described.

Different perspective views of the field-guiding element 29 are shown in FIGS. 12-15. In the embodiment according to FIG. 12, the field-guiding element 29 is designed as a cuboid, in particular in the form of a bar, which extends over the entire length of the transverse seal. In the exemplary embodiment according to FIG. 13, the field-guiding element 29 is again designed as a cuboid, but has two recesses 50. This forms a shape with three legs. The exemplary embodiment according to FIG. 14 again comprises a cuboid structure with two recesses 50, similar to FIG. 13. In addition, two bevels 52 or chamfers are preferably provided, which connect the surfaces of the recesses 50 with the two outer limbs of the field-guiding element 29. The field-guiding element 29 of the embodiment of Figure 15 consists of several juxtaposed elements 54. By the illustrated embodiments 12-15 of the field line profile in the direction of the packaging material 10 is further improved. This can further increase the quality of the seal.

The sealing device 20 operates as induction sealing device. For this purpose, the coil 25 is connected in a known manner with a high-frequency power source, so that short-circuit currents and thus heat is generated in the packaging material 10 to be sealed. The frequency ranges are for example in the order of 20 to 120 kHz, preferably in the range 30-40 kHz. For this purpose, the packaging material or the packaging material 10 consists, for example, of at least one conductive layer and one polymer layer. So that could be

Packaging material, for example, comprise an aluminum layer. When the coils 25 are energized, a magnetic field is created which propagates through the magnetic flux in the coil core 24. The magnetic circuit closes over the field guiding elements 29 and via the magnetic field guiding elements 28 along the guided field lines 44, which again enter or exit the other end of the inductor.

The device described is particularly suitable for sealing a packaging material 10, in particular in packaging machines 8, particularly preferably in tubular bag machines. However, the use is not limited to this.

Claims

claims

A device for sealing a packaging material (10), comprising at least one sealing device (20) with at least one sealing jaw (26) and at least one counter-holder (31), which are designed to be movable relative to each other, wherein the sealing device (20) at least one coil

(25) with a coil core (24) for generating a magnetic field, which passes through the seal to be sealed by the packaging material (10), characterized in that at least one magnetic field guiding element (28) is provided, the coil (25) at least partially surrounds for guiding the magnetic field of the coil (25) to be sealed

Packaging material (10).

2. Device according to one of the preceding claims, characterized

in that at least one field-guiding element (29) is provided for influencing the magnetic field, wherein the packaging material (10) to be sealed can be arranged between the coil (25) and the field-guiding element (29).

3. Device according to one of the preceding claims, characterized

characterized in that at least one sealing profile (38,39) is provided, wherein the sealing profile (38) with the magnetic field leading element (28) and / or the coil core (24) and / or field-guiding element (29) is connected and / or wherein the sealing profile (38) between the

Magnetic field leading element (28) and the packaging material (10) can be arranged.

4. Device according to one of the preceding claims, characterized

in that the coil (25) and / or the magnetic field guiding element (28) and / or the field-guiding element (29) on the sealing jaw

(26) or is arranged on the counter-holder (31) or are.

5. Device according to one of the preceding claims, characterized

characterized in that the magnetic field guiding element (28) at least partially has a U-shaped cross-section and / or a chamfer (30).

6. Device according to one of the preceding claims, characterized in that the magnetic field leading element (28) surrounds the coil (25) from five sides and is open in the direction of the packaging material (10).

7. Device according to one of the preceding claims, characterized

in that the magnetic field guiding element (28) is connected to the spool core (24), in particular on a side remote from the packaging material (10).

8. Device according to one of the preceding claims, characterized

in that the spool core (24) comprises at least one gap, in particular for receiving a separating means (19).

9. Device according to one of the preceding claims, characterized

characterized in that the magnetic field-guiding element (28) and / or the field-guiding element (29) and / or the coil core of a magnetically conductive material, in particular a soft magnetic material, particularly preferably of a ferrite, particularly preferably of at least one ferrite plate consists.

10. Device according to one of the preceding claims, characterized

in that the field-guiding element (29) is cuboid, in particular rod-shaped, and / or at least one

Recess (50) and / or at least one bevel (52) and / or a plurality of elements (54).

1 1. Device according to one of the preceding claims, characterized

in that the coil core (24) comprises at least one plate, preferably two plates, in particular a ferrite plate.

12. Device according to one of the preceding claims, characterized

in that at least the field-guiding element (29) is arranged on the counter-holder (31) or the sealing jaw (26).

13. Device according to one of the preceding claims, characterized

in that at least two field-guiding elements (29) are provided, in particular at a seam area (11) or at a multi-layer area of the packaging material (10) to be sealed.

14. Device according to one of the preceding claims, characterized in that the field-guiding element (29) fixed to the

Counter-holder (31) or the sealing jaw (26) is connected and / or in the

Counter holder (31) or in the sealing jaw (26) can be inserted.

15. Device according to one of the preceding claims, characterized

characterized in that windings of the coil (25) are formed substantially parallel to the packaging material (10) to be sealed.