SEALING DEVICE

Abstract

The present invention relates to a sealing device (1, 101, 201) for sealing a packaging material (7, 107) enclosing a filling material (29) to provide portion-packed oral pouched snuff products (43). The sealing device comprises an anvil (3, 103, 203) with a first operation surface (11, 111, 211) and a sonotrode (5, 105, 205) with a second operation surface (13, 113), the anvil and the sonotrode being arranged to allow passage of the packaging material therebetween, the second operation surface being located opposite the first operation surface during operation of the sealing device. The first and second operation surfaces are arranged to weld a first portion (7a, 107a) of the packaging material to a second portion (7b, 107b) of the packaging material. At least one of the first or second operation surfaces comprises a first welding surface (11a, 111a) defining a first extension plane and a second welding surface (11b, 111b) defining a second extension plane, which has a different orientation than the first extension plane. The first and second welding surfaces are partly delimited by a cutting edge (15, 115, 215) having an extension direction along the first and second welding surfaces, such that the cutting edge separates the first welding surface from the second welding surface. The present invention further relates to an arrangement (19) for manufacturing of portion-packed oral pouched snuff products, which arrangement comprises such a sealing device. The present invention also relates to a method for portion-packing of an oral pouched snuff product.

Claims

1. A sealing device for sealing a packaging material enclosing a filling material to provide portion-packed oral pouched snuff products, said sealing device comprising an anvil with a first operation surface and a sonotrode with a second operation surface, said anvil and said sonotrode being configured to allow passage of said packaging material therebetween, said second operation surface being located opposite said first operation surface during operation of said sealing device, said first and said second operation surfaces being configured to weld a first portion of said packaging material to a second portion of said packaging material, wherein: at least one of said first or said second operation surfaces comprises a first welding surface defining a first extension plane and a second welding surface defining a second extension plane, which has a different orientation than said first extension plane, said first and said second welding surfaces being partly delimited by a cutting edge having an extension direction along said first and second welding surfaces, such that said cutting edge separates said first welding surface from said second welding surface, wherein said first and said second operation surfaces are configured for simultaneous welding and cutting of said packaging material, and wherein said first and said second welding surfaces are configured to provide said welding, and said cutting edge is configured to provide said cutting, and wherein said first extension plane or said second extension plane forms an angle (, ) in the range from 72 to 90 in relation to a main direction of said anvil or sonotrode comprising said first and said second welding surfaces, said main direction being perpendicular to an extension direction of said cutting edge.

2-18. (canceled)

19. The sealing device according to claim 1, wherein said first welding surface or said second welding surface comprises a planar surface, said planar surface being delimited at one side by said cutting edge.

20. The sealing device according to claim 1, wherein said angle formed by said first extension plane or said second extension plane in relation to said main direction of said anvil or sonotrode comprising said first and said second welding surfaces, said main direction being perpendicular to an extension direction of said cutting edge, is in the range from 72 to 89.

21. The sealing device according to claim 1, wherein the sizes of said angles of said first and second welding surfaces are equal.

22. The sealing device according to claim 1, wherein at least one of said sonotrode or said anvil comprises a disc, wherein a peripheral surface of said disc comprises said first and said second operation surfaces.

23. The sealing device according to claim 22, wherein said first welding surface, said second welding surface, and said cutting edge extend along a circumference of said disc.

24. The sealing device according to claim 1, wherein at least one of said sonotrode or said anvil is configured to be displaced in a reciprocating way in relation to the other of said sonotrode or said anvil.

25. The sealing device according to claim 24, wherein said at least one of said sonotrode and said anvil is configured to be displaced together with said packaging material in a direction perpendicular to said extension direction of said cutting edge while performing simultaneous cutting and welding.

26. An arrangement for manufacturing of portion-packed oral pouched snuff products, said arrangement comprising: a first feeding unit configured to supply an advancing web of packaging material, a second feeding unit configured to supply a filling material to said advancing web, an enclosing unit for arranging said web of packaging material to enclose said filling material, said enclosing unit being located before or after said second feeding unit, and at least one sealing device according to claim 1 being configured for sealing said packaging material, thereby making at least one seal of said portion-packed oral pouched snuff products.

27. The arrangement according to claim 26, wherein said enclosing unit comprises a forming unit configured to shape a tubular web of said packaging material.

28. The arrangement according to claim 26 comprising: a first sealing device according to claim 1 for providing said portion-packed oral pouched snuff products with a longitudinal seal, or a second sealing device according to claim 1 for providing said portion-packed oral pouched snuff products with a transverse seal.

29. The arrangement according to claim 26, wherein said arrangement comprises a pulling unit located downstream of said at least one sealing device according to claim 1, at a distance from said sealing device substantially corresponding to an extension of one of said portion-packed oral pouched snuff products in a direction perpendicular to said extension direction of said cutting edge of said sealing device.

30. A method for portion-packing of an oral pouched snuff product, comprising: supplying and advancing a web of packaging material, said web of packaging material advancing in a direction of travel, supplying a filling material to said advancing web of packaging material, arranging said advancing web of packaging material to enclose said filling material, said arranging being performed before or after supplying said filling material, passing said web in a gap formed by a sonotrode and an anvil of a sealing device according to claim 1, wherein: the method further comprises: simultaneously welding and cutting said web of packaging material using said sealing device according to claim 1, wherein said cutting is performed such that a cut is located in a welded area, said cut being placed in a central region of welded portions of said packaging material, wherein said central region comprises the centre +/40% of the total width of said welded portions.

31. The method according to claim 30 wherein said advancing web of packaging material is configured to form to a tubular web to enclose said filling material.

32. The method according to claim 30, wherein said simultaneous cutting and welding is performed along, or substantially along, a direction of travel of said web of packaging material.

33. The method according to claim 30, wherein said simultaneous cutting and welding is performed along, or substantially along, a direction being perpendicular to said direction of travel of said web of packaging material.

34. The method according to claim 30, wherein said sonotrode or said anvil is displaced in said direction of travel together with said web of packaging material while performing said welding and cutting.

35. The method according to claim 30, further comprising pulling said web at least in said direction of travel, said pulling being performed downstream of said welding and cutting, at a distance from said welding and cutting corresponding to the extension of said portion-packed oral pouched snuff product in said direction of travel.

36. The sealing device of claim 1, wherein said first extension plane and said second extension plane form an angle (, ) in the range from 72 to 90 in relation to a main direction of said anvil or sonotrode comprising said first and said second welding surfaces, said main direction being perpendicular to an extension direction of said cutting edge.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended drawings wherein:

[0067] FIG. 1 illustrates a sealing device according to a first embodiment of the invention,

[0068] FIG. 2 is a detailed cross-sectional view showing the sealing device in operation,

[0069] FIG. 3a-g illustrate an arrangement according to the invention for manufacturing of portion-packed oral pouched snuff products,

[0070] FIG. 4 illustrates a cross-section through a nip of a pulling unit,

[0071] FIG. 5 illustrates a sealing device according to a second embodiment of the invention and a sealing device according to a third embodiment of the invention,

[0072] FIG. 6 is a detailed view of the anvil of the sealing device according to the second embodiment of the invention, and

[0073] FIG. 7 is a detailed view of an alternative anvil.

[0074] It should be noted that the appended drawings are not necessarily drawn to scale and that the dimensions of some features of the present invention may have been exaggerated for the sake of clarity.

DETAILED DESCRIPTION

[0075] The invention will, in the following, be exemplified by embodiments. It should however be realized that the embodiments are included in order to explain principles of the invention and not to limit the scope of the invention, defined by the appended claims. Details from two or more of the embodiments may be combined with each other.

[0076] FIGS. 1 and 2 illustrate a sealing device 1 for sealing a packaging material enclosing a filling material to provide portion-packed oral pouched snuff products according to a first embodiment of the invention. FIG. 1 is a perspective view. FIG. 2 is a detailed cross-sectional view showing the sealing device 1 in operation.

[0077] The sealing device 1 comprises an anvil 3 and a sonotrode 5, which is arranged opposite to the anvil 3 to allow passage of the packaging material 7 in a gap 9 formed between the sonotrode 5 and the anvil 3. The sonotrode 5 is adapted for transmitting ultrasonic energy. In the illustrated embodiment of FIG. 1, a portion 10 of a filling material has already been enclosed by the packaging material 7 before reaching the sealing device 1. The filling material comprises a smokeless tobacco or tobacco-free material, which may be nicotine-containing or nicotine free. The filling material may also be referred to as filling composition or snuff composition. A portion-packed oral pouched snuff product comprises the portion 10 of the filling material and a piece of the packaging material 7, the packaging material 7 enclosing the portion 10 of the filling material.

[0078] The anvil 3 and the sonotrode 5 are configured for simultaneous welding and cutting of the packaging material 7. The welding operation is utilized to provide the pouched snuff product with one or more seals, which may be longitudinal seals and/or transverse seals. The cutting operation is utilized to cut the packaging material 7, e.g. to separate two consecutive pouched products from each other or to separate superfluous packaging material from a longitudinal seal.

[0079] The packaging material 7 is adapted to advance in a direction of travel DT through the gap 9. The orientation of the direction of travel DT in relation to the orientation of the sonotrode 5 and the anvil 3 depends on whether a longitudinal or transverse seal is to be formed. For a longitudinal seal, the direction of travel would be out of the paper in FIG. 1. For providing a transverse seal 6, as is illustrated in FIG. 1, the direction of travel DT is downwards in FIG. 1.

[0080] The packaging material 7 is formed to a tubular web, which may comprise a longitudinal seal 8. At the desired location of the transverse seal 6, there is no filling material. Instead a first portion 7a of the packaging material 7 directly faces a second portion 7b of the packaging material 7. These two portions 7a, 7b are to be welded together in the transverse seal 6.

[0081] The anvil 3 comprises a first operation surface 11 and the sonotrode 5 comprises a 25 second operation surface 13, which is located opposite to the first operation surface 11. The first operation surface 11 of the anvil 3 comprises a first welding surface 11a and a second welding surface 11b. A cutting edge 15 delimits the first welding surface 11a and the second welding surface 11b from each other. The cutting edge 15 is located at a portion of the first operation surface 11 being adjacent to the narrowest portion of the gap 9. The cutting edge 15 is adapted to cut through the packaging material 7. In the illustrated embodiment, the cutting edge 15 is adapted to cut through the first and second portions 7a, 7b of the packing material 7. The second operation surface 13 is non-angled, i.e. flat. The direction of travel DT is substantially parallel to the non-angled operation surface 13 of the sonotrode 5.

[0082] The extension direction of the cutting edge 15 defines a first direction D.sub.1 of the anvil 3. A main direction A of the anvil 3 defines a second direction D.sub.2, which is perpendicular to the first direction D.sub.1. A third direction D.sub.3 is perpendicular to both the first direction D.sub.1 and to the second direction D.sub.2. Since FIGS. 1 and 2 illustrates providing the transverse seal 6, the first direction D.sub.1 substantially coincides with a transverse direction of the packing material 7 and the third direction D.sub.3 coincides with the direction of travel DT of packaging material 7 but pointing in the opposite direction.

[0083] The first welding surface 11a defines a first extension plane. In the illustrated embodiment, the first welding surface 11a constitutes an inclined planar surface, such that the first extension plane is defined by the inclined planar surface. In case, the first welding surface 11a does not form a planar surface, e.g. by having a curved surface, the first extension plane is defined as a mean plane to the first welding surface 11a, i.e. the plane having the least squared distance from the first welding surface 11a to that plane.

[0084] The first extension plane assumes an angle being between 70 and 90 in relation to the main direction A of the anvil 3, being parallel to the second direction D.sub.2, preferably the angle being in the range from 72 to 89, more preferably from 75 to 88, most preferably from 80 to 85. In the illustrated embodiment, the angle is substantially 82.

[0085] The second welding surface 11b defines a second extension plane. In the illustrated embodiment, the second welding surface 11b constitutes an inclined planar surface, such that the second extension plane is defined by the inclined planar surface. The orientation of the second extension plane differs from that of that the first extension plane. The second extension plane assumes an angle being between 70 and 90 in relation to the main direction A of the anvil 3, preferably the angle being in the range from 72 to 89, more preferably from 75 to 88, most preferably from 80 to 85. In the illustrated embodiment, the angle is substantially 82. Hence, the angles , of the first and second welding surfaces 11a, 11b are of equal size but different orientation in the illustrated embodiments of FIGS. 1 and 2. However, also their sizes may differ.

[0086] As mentioned above, the second operation surface 13 is non-angled. It thus assumes an angle of 90 in relation to the second direction D.sub.2.

[0087] The cutting edge 15 delimits one side of the first welding surface 11a and the corresponding side of the second welding surface 11b. When viewed along the main direction A, the first welding surface 11a and the second welding surface 11b form a rectangular region. One side of the rectangles is delimited by the cutting edge 15. The cutting edge 15 thus separates the first welding surface 11a from the second welding surface 11b. Yet the two welding surfaces 11a, 11b extend all the way to the cutting edge 15, such that there is no interspace between the weld and the cut, i.e. there are no non-welded portions adjacent to the cut.

[0088] The first welding surface 11a comprises a first welding zone 17a delimited at one side by the cutting edge 15, and the second welding surface 11b comprises a second welding zone 17b also delimited at one side by the cutting edge 15. In the first and second welding zones 17a, 17b, the anvil 3 and the sonotrode 5 are close enough to be able to melt the first and second portions 7a, 7b of the packaging material and thereby join them by welding. The widths w.sub.1, w.sub.2 of the first and second welding zones 17a, 17b in the third direction D.sub.3 depend on characteristics of the sealing device 1, the packaging material 7 and their interaction. Examples of device characteristics are angles of the operation surfaces 11, 13 relative to each other, distance between the operation surfaces 11, 13, material properties of the anvil 3 and the sonotrode 5, frequency and energy of the ultra sound of the sonotrode 5. Examples of packaging material characteristics are type of material, melting point, thickness, surface roughness. Examples of interaction characteristics are gap width in relation to thickness of packaging material and pressure used by the anvil 3 and the sonotrode 5 during cutting and welding.

[0089] In the illustrated embodiment the first and second welding zones 17a, 17b have the same widths w.sub.1, w.sub.2, but the widths w.sub.1, w.sub.2 may also differ. Further, the width w.sub.1 of the first welding zone 17a may be the same as for the first operation surface 11 and/or the width w.sub.2 of the second welding zone 17b may be the same as for the second operation surface 13. However, typically the welding zone is narrower than the operation surface, i.e. the width of the weld is less than the width of the gap 9 as seen along the direction of travel DT.

[0090] In the sealing device as described herein, the packaging material 7 is welded on both sides of the cutting edge 15. This configuration could suitably be used for a transverse seal 6, as is illustrated in FIGS. 1 and 2, wherein the cut performed by the cutting edge 15 is utilized to separate individual pouched products and for which there is a desire that both ends of the individual pouched products should be adequately sealed. The direction of travel DT would thus be parallel to the non-angled second operation surface 13 but substantially perpendicular to the extension direction of the cutting edge 15, see FIGS. 1 and 2. For such a transverse seal 6, it may be advantageous that the angles , of the extension planes are of the same sizes and the first and second welding zones 17a, 17b have the same widths w.sub.1, w.sub.2.

[0091] A sealing device like the one illustrated in FIGS. 1 and 2 would also be suitable for making a longitudinal seal. The direction of travel would then be in the first direction D.sub.1, i.e. parallel to the extension direction of the cutting edge 15, i.e. out of the paper in FIG. 2. In that case, parts of the packaging material 7 being outside the cut, which parts are to be removed e.g. as strips, are joined to each other. The combined strip will be stronger than the individual strips and will thus better withstand a pulling force, such that it is less likely to be torn off. Details of making a longitudinal seal are provided below in conjunction with FIGS. 5-7.

[0092] FIGS. 3a-g illustrate an arrangement 19 according to the invention for manufacturing of portion-packed oral pouched snuff products 43. The arrangement 19 comprises a first feeding unit 23 for supplying a planar web 25 of the packaging material 7, a second feeding unit 27 for supplying a filling material 29 to the advancing web 25, a forming unit 31 for forming a tubular web 32 of the planar web 25 of the packaging material 7, a device 33 for making a longitudinal seal and a device for making a transverse seal, illustrated as the sealing device 1 of FIGS. 1 and 2.

[0093] The second feeding unit 27 may be located downstream or upstream of the forming unit 31. If placed downstream, the web 25 is first formed to a tubular web 32 and thereafter the filling material 29 is placed in the tubular web 32 as a portion 10, as for the arrangement 19 illustrated in FIGS. 3a-g. Alternatively, the filling material 29 may be placed on the planar web 25 as a portion 10 before the planar web 25 is formed to a tubular web, such that the packaging material 7 is arranged around the snuff portion to form the tubular web, thereby enclosing the snuff portion 10.

[0094] At least one of the devices for making a longitudinal seal and the device for making a transverse seam may utilize ultra-sound to perform simultaneous welding and cutting, e.g. by the sealing device as described in conjunction with FIGS. 1-2, in order to obtain a seal. Hence, in the arrangement 19 according to the invention, welding and cutting is performed simultaneously and in the same operation step for at least one of the seals.

[0095] In the illustrated embodiment of FIGS. 3a-g, the transverse seal 6 is formed by a device like the one described in conjunction with FIGS. 1 and 2. The transverse seal 6 may have a width equal to or less than 2 mm, such as within the range of from 0.1 mm to 2 mm or 0.1 mm to 1 mm or 0.1 to 0.5 mm, although the width is exaggerated in FIGS. 3a-g in order to better illustrate what happens in the gap 9 between the anvil 3 and the sonotrode 5 during welding and cutting.

[0096] The sonotrode 5 and the anvil 3 are arranged to be displaced in a reciprocating way in relation to the tubular web 32 in the second direction D.sub.2, between a first position, illustrated in FIG. 3a, being in contact with the tubular web 32 and a position, illustrated in FIG. 3c, being out of contact with the tubular web 32.

[0097] Further, the sonotrode 5 and the anvil 3 are adapted to follow the tubular web 32 when moving in the direction of travel DT, i.e. in a direction opposite to the third direction D.sub.3, while performing the simultaneous welding and cutting, in order to be able to follow the tubular web 32 to a downstream position, illustrated in FIG. 3b.

[0098] The anvil 3 moves along a path 37 which has a first portion 37a parallel to and adjacent to the tubular web 32, a second portion 37b moving the anvil 3 away from the tubular web 32, a third portion 37c bringing the anvil 3 back upstream and a fourth portion 37d bringing the anvil 3 back into contact with the tubular web 32. The sonotrode 5 follows a corresponding path 39, having corresponding portions 39a, 39b, 39c, 39d. See paths 37, 39 illustrated in FIG. 3a. The paths 37, 39 are further described below.

[0099] FIG. 3a illustrates a start of the method. A longitudinal seal, e.g. like the longitudinal seal 8 illustrated in FIG. 1, is continuously formed in the advancing tubular web 32 by the device 33 for making a longitudinal seal. The anvil 3 and the sonotrode 5 assume the first position, in which they start welding. A portion 10 of the filling material 29 is filled from above into the tubular web 32. The filling material moves downwards, e.g. by gravity, until it reaches the portion of the tubular web 32, which is in the gap 9 between the anvil 3 and the sonotrode 5.

[0100] The anvil 3 and the sonotrode 5 move downstream together with the tubular web 32 while performing the welding along the respective first portions 37a, 39a of their paths. The anvil 3 and the sonotrode 5 then reach a second position being downstream of the first position but yet in contact with the tubular web 32. See FIG. 3b. The tubular web 32 is cut by the cutting edge 15 leaving a transverse seal 41.

[0101] Thereafter the anvil 3 and the sonotrode 5 are moved away from the tubular web 32 along the second portions 37b, 39b of their respective paths until they reach a respective third position, such that they are no longer in contact. The already formed transverse seal 41 prevents the portion 10 of the filling material from falling out. See FIG. 3c.

[0102] As a next step, the anvil 3 and the sonotrode 5 are moved back upstream along the third portions 37c, 39c of their respective paths to a fourth position being out of contact with the tubular web 32. See FIG. 3d.

[0103] Then the anvil 3 and the sonotrode 5 are moved back to the first position along the fourth portions 37d, 39d of their respective paths, such that they start forming a new transverse seal. See FIG. 3e.

[0104] The anvil 3 and the sonotrode 5 move along the respective first portions 37a, 39a of their paths together with the tubular web 32 while performing the welding until the anvil 3 and the sonotrode 5 reach the second position being downstream of the first position but yet in contact with the tubular web 32. See FIG. 3f. The tubular web 32 is cut by the cutting edge 15, leaving a transverse seal 45 at the upper edge of the pouched product 43 and a corresponding transverse seal 46 at the lower edge of the next pouched product, which has been filled by a next portion 10 of the filling material.

[0105] Thereafter the anvil 3 and the sonotrode 5 are moved away from the tubular web 32 along the second portions 37b, 39b of their respective paths until they reach a respective third position, illustrated in FIG. 3g, such that they are no longer in contact, as is already described above for FIG. 3c. The anvil 3 and the sonotrode 5 continue to move along their paths 37, 39 described above, while the tubular web 32 moves in the direction of travel DT.

[0106] In order to help separating the tubular web 32 in the cut, the arrangement 19 may further comprise a pulling unit, illustrated in FIGS. 3f and 3g as a nip 47 between a pair of rollers 49, 51 arranged to pull the pouched product 43 in the direction of travel DT. Thereby the tubular web 32 is tensioned in a controllable way in order to make a separation of the pouched product 43 from the next pouched product easier. The distance z between the nip 47 and the cutting edge 15 when the sealing device is in the second position, see FIG. 3f, roughly corresponds to the extension of the pouched product 43 in the direction of travel DT. Hence, if the arrangement 19 is utilized for manufacturing portion-packed oral pouched snuff products of different sizes, the distance z is preferably adjustable. After passing the nip 47, the pouched product 43 is placed on a conveyer 52. See FIG. 3g.

[0107] FIG. 4 illustrates a cross-section through the nip 47 as seen from above in FIG. 3g. In order to be able to pull the pouched product 43 filled with the portion 10 of the filling material without destroying the pouched product 43 in the nip 47, at least one of the rolls, illustrated as the left-hand roll 49, is provided with a plurality of ridges 53, having interspaces 55 between the ridges 53. The ridges 53 will help to pull the pouched product 43, while the interspaces 55 give room for the filling material. Thereby, it is possible to pull the pouched product 43 through the nip 47 without destroying it. There are at least two ridges 53. The other roll 51, may be flat as is illustrated, or it may also comprises ridges.

[0108] The longitudinal seal, e.g. like the longitudinal seal 8 illustrated in FIG. 1, may be performed by heat-melt welding in the device 33 for making a longitudinal seal.

[0109] As an alternative to the arrangement 19 described above in conjunction with FIGS. 3a-g, pouched smokeless tobacco products may be produced by placing portions of moist snuff on a nonwoven web using a device disclosed in U.S. Pat. No. 6,135,120, as mentioned above. This technique is herein referred to as the NYPS technique. According to the NYPS technique, the individual portion of smokeless tobacco composition is placed on the packaging material, which forms a tape. In order to enclose the portion of the smokeless tobacco composition, the packaging material is wrapped around the portion of the smokeless tobacco composition and sealed by a longitudinal seal. Both lateral edges of the packaging web may face in the same direction, e.g. upwards, such that a fin seal is made. Alternatively, the lateral edge portions of the packaging web may overlap, such that a lap seal is created. A combined fin and lap seal may be formed by letting the lateral edges of the packaging web face in the same direction forming a fin, optionally forming a fin seal in the fin, and then lap sealing the fin to the outer surface of the pouch.

[0110] FIG. 5 illustrates a device 101 according to a second embodiment of the invention for making simultaneous welding and cutting for a longitudinal seal 102. Upstream of the device 101, a tubular web 132 is formed, e.g. by folding plates, not illustrated. The tubular web 132 may e.g. be formed as in the NYPS technique. In the embodiment illustrated in FIG. 5, the anvil 103 comprises a rotary disc. Also the sonotrode 105 comprises a rotary disc. A gap 109 is formed between the sonotrode 105 and the anvil 103, through which two lateral edge portions 107a, 107b of the packaging material 107 pass. The first operation surface 111 of the anvil 103 comprises two welding surfaces 111a, 111b separated by a cutting edge 115. The welding surfaces 111a, 111b and the cutting edge 115 follow the perimeter of the disc-shaped anvil 103 in a circumferential direction. Preferably, they extend all the way around the circumference. The sonotrode 105 comprises a second operation surface 113.

[0111] FIG. 6 illustrates a detailed view of the anvil 103 as seen in cross-sectional view. The first welding surface 111a is delimited from the second welding surface 111b by the cutting edge 115. The details are corresponding to those already described in conjunction with FIG. 2. The first welding surface 111a forms a first extension plane forming an angle and the second welding surface 111b forms a second extension plane forming an angle . The first welding surface 111a comprises a first welding zone having a width w.sub.1 delimited at one side by the cutting edge 115, and the second welding surface 111b comprises a second welding zone having a width w.sub.2 also delimited at one side by the cutting edge 115. In the first and second welding zones the anvil 3 and the sonotrode 5 are close enough to be able to melt the first and second portions 107a, 107b of the packaging material and thereby join them by welding.

[0112] In the longitudinal seal 102, the packaging material being outside of the cut is superfluous and may hence be removed. In the embodiment of FIG. 5, the packing material 107 is welded on both sides of the cutting edge 115, i.e. both above and below the cut. This may be advantageous when removing the packaging material outside the cut. The superfluous packaging material may be removed as an edge strip 117. Since the edge strip 117 in the illustrated embodiment comprises cut-away material from both edge portions 107a, 107b welded together, the strength of the combined edge strip 117 is higher than would be the case, if the two edge strips were removed separately, i.e. not welded to each other.

[0113] However, it is also feasible to remove each edge strip separately. In that case, an anvil with a single welding surface would be feasible, e.g. like the one illustrated in FIG. 7, wherein the anvil 103 comprising the welding surface 111 and the cutting edge 115 is located opposite to the sonotrode 105. Both the anvil 103 and the sonotrode 105 comprise a rotary disc in a corresponding way to the second embodiment illustrated in FIG. 5. The welding surface 111 and the cutting edge 115 extend in the circumferential direction along the peripheral surface of the anvil 103.

[0114] Going back again to the embodiment of FIG. 5, as a next step after forming the longitudinal seal 102, transverse seals are formed, e.g. by a sealing device 201 according to a third embodiment of the invention, also illustrated in FIG. 5. The sonotrode 205 comprises a rotary disc. Also the anvil 203 comprises a rotary disc. A gap 209 is formed between the sonotrode 205 and the anvil 203, through which the tubular web 132 filled with portions 10 of the filling material passes. Since the seal is to be made in a transverse direction, the operation surface 211 of the anvil 203 is located at the perimeter of the anvil 203 extending in an axial direction of the rotary discs. The anvil 203 comprises one or more operation surfaces 211, in the illustrated embodiment three, which are evenly distributed in the circumferential direction, such that the distance between two cutting edges 215 correspond to the longitudinal extension of the pouched product. Correspondingly, the operation surface 213 of the sonotrode 205 is located at the perimeter of the sonotrode 205. The sonotrode may comprise one or more operation surfaces, similar to the one illustrated in FIG. 2, which are evenly distributed in the circumferential direction, such that the distance between two operation surfaces correspond to the longitudinal extension of the pouched product. A cross-section through the gap 209 may then look like illustrated in FIG. 2.

[0115] Further modifications of the invention within the scope of the appended claims are feasible. As such, the present invention should not be considered as limited by the embodiments and figures described herein. Rather, the full scope of the invention should be determined by the appended claims, with reference to the description and drawings.