Composite Containers For Bulk Solids, Related Systems And Methods

Abstract

A container for holding bulk solids, the container including a tubular body extending at least partially around an interior of the container to form a tubular body having a top end and a bottom end, at least one sealing member positioned in the interior of the container spaced away from each of the top end and the bottom end of the tubular body, the at least one sealing member sealably engaging at least a portion of the tubular body, a reclosable lid attached to the top end of the tubular body to form a closed top end of the container, the reclosable lid comprising pulp fibers, and a bottom plate attached to the bottom end of the tubular body to form a closed bottom end of the container, the bottom plate comprising pulp fibers.

Claims

1. A container for holding bulk solids, the container comprising: a tubular body extending at least partially around an interior of the container to form a tubular body having a top end and a bottom end; at least one sealing member positioned in the interior of the container spaced away from each of the top end and the bottom end of the tubular body, the at least one sealing member sealably engaging at least a portion of the tubular body; a reclosable lid attached to the top end of the tubular body to form a closed top end of the container, the reclosable lid comprising molded pulp fibers; and a bottom plate attached to the bottom end of the tubular body to form a closed bottom end of the container, the bottom plate comprising molded pulp fibers.

2. The container of claim 1, wherein the bottom plate is free from plastic material.

3. The container of claim 2, wherein the bottom plate defines an outward flange engaged with the bottom end of the tubular body.

4. The container of claim 2, further comprising a rim attached to the top end of the tubular body above the sealing member such that the reclosable lid contacts the rim.

5. The container of claim 4, wherein the rim comprises pulp fibers and is free from plastic material.

6. The method container of claim 4, wherein the at least one sealing member is a top sealing member spaced away from each of the top end of the tubular body and the bottom end of the tubular body, and the container further comprises a bottom sealing member positioned in the container spaced away from each of the top end of the tubular body, the bottom end of the tubular body, and the first sealing member.

7. A method of forming a container for holding bulk solids, the method comprising: obtaining a body blank; positioning the body blank extending at least partially around an interior of the container to form a tubular body having a top end and a bottom end; positioning at least one sealing member in the interior of the container spaced away from each of the top end and the bottom end of the tubular body, the at least one sealing member sealably engaging at least a portion of the tubular body; attaching a reclosable lid to the top end of the tubular body to form a closed top end of the container, the reclosable lid comprising molded pulp fibers; and attaching a bottom plate to the bottom end of the tubular body to form a closed bottom end of the container, the bottom plate comprising molded pulp fibers.

8. The method of claim 7, wherein the bottom plate is free from plastic material.

9. The method of claim 8, wherein the bottom plate defines an outward flange, and attaching the bottom plate comprises engaging the bottom end of the tubular body with the flange of the bottom plate.

10. The method of claim 8, wherein attaching the reclosable lid to the top end of the tubular body comprises attaching a rim to the top end of the tubular body above the at least one sealing member such that the reclosable lid contacts the rim.

11. The method of claim 10, wherein the rim comprises pulp fibers and is free from plastic material.

12. The method of claim 11, wherein the at least one sealing member is a top sealing member spaced away from each of the top end of the tubular body and the bottom end of the tubular body, and the method further comprises positioning a bottom sealing member in the container spaced away from each of the top end of the tubular body, the bottom end of the tubular body, and the first sealing member, the bottom sealing member sealably engaging the tubular body.

13. The method of claim 7, wherein positioning the body blank extending at least partially around the interior of the container comprises transferring the body blank to a body forming station, bending the body blank with the body forming station, and bringing two opposing edges of said body blank together in an end-to-end join with the body forming station to form an intermediate container, the at least one sealing member is a top sealing member, and positioning the top sealing member in the interior of the container comprises transferring the intermediate container to a top sealing station and attaching the top sealing member to the tubular body with the top sealing station.

14. The method of claim 13, further comprising transferring the intermediate container to a filling station and filling the intermediate can with bulk solids through the bottom end of the tubular body with the filling station to form a filled intermediate container.

15. The method of claim 14, further comprising transferring the filled intermediate container to a bottom sealing station and sealably attaching a bottom sealing member to the tubular body such that the bottom sealing member is spaced away from the top sealing member.

16. The method of claim 15, further comprising positioning filled intermediate container on a conveyor and transferring the filled intermediate container to a lid attachment station, attaching the reclosable lid comprises attaching the reclosable lid to the top end of the tubular body with the lid attachment station.

17. The method of claim 16, further comprising transferring the filled intermediate container to a top rim application station and attaching a rim to the top end of the tubular body above the sealing member with the top rim application station such that the reclosable lid is positioned contacting the rim.

18. The method of claim 17, wherein filling the intermediate can with bulk solids comprises supplying a protective gas to the bulk solids.

19. The method of claim 18, further comprising positioning a scoop between the top sealing member and the reclosable lid in the interior of the container.

20. An assembly line for forming a container for holding bulk solids, the assembly line comprising: a supply of body blanks, sealing members, reclosable lids, and bottom plates, the bottom plates and the reclosable lids comprising molded pulp fibers; a body forming station for bending a body blank from the supply of body blanks at least partially around an interior of the container; a sealing station for attaching a sealing member from the supply of sealing members to the tubular body in the interior of the container; a filling station for filing the interior of the container with bulk solids through a bottom end of the tubular body; a bottom plate application station for attaching a bottom plate from the supply of bottom plates to the bottom end of the tubular body to form a closed bottom end of the container; a lid attachment station for attaching a reclosable lid from the supply of reclosable lids to the top end of the tubular body to form a closed top end of the container; and a body plate application station for attaching a bottom plate from the supply of bottom plates to the bottom end of the tubular body to form a closed bottom end of the container.

21. The assembly line of claim 20, wherein the bottom plates of the supply of bottom plates are free from plastic material.

22. The assembly line of claim 21, wherein the reclosable lids of the supply of reclosable lids comprises pulp fibers.

23. The assembly line of claim 20, further comprising a supply of rims and a rim attachment station configured to apply a rim from the supply of rims to the top end of the tubular body.

24. The assembly line of claim 23, wherein the rims of the supply of rims comprise pulp fibers and are free from plastic material.

25. The assembly line of claim 24, wherein the sealing members are top sealing members, the sealing station is a top sealing station for attaching a top sealing member of the supply of top sealing members to the tubular body in the interior of the container, and the assembly line further comprises a supply of bottom sealing members and a bottom sealing station, the bottom sealing station configured to apply a bottom sealing member of the supply of bottom sealing members to the tubular body in the interior of the container spaced away from the top sealing member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0183] The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:

[0184] FIG. 1 shows a schematic view of an assembly line for producing and filling a composite can;

[0185] FIG. 2a shows an exploded view of a composite can as disclosed herein;

[0186] FIG. 2b shows a scoop and a stack of scoops;

[0187] FIG. 3 shows the composite can in FIG. 2a with all components assembled;

[0188] FIG. 4 shows a can component applicator;

[0189] FIG. 5 shows an attachment unit which may be part of a can component applicator as shown in FIG. 4 in a first production stage;

[0190] FIG. 6 shows the attachment unit in FIG. 5 in a second production stage;

[0191] FIG. 7 shows a transport plate with transfer cavities; and

[0192] FIG. 8 shows a positioning device.

DETAILED DESCRIPTION

[0193] The invention will, in the following, be exemplified by embodiments. The embodiments are included in order to explain principles of the invention and not to limit the scope of the invention, as defined by the appended claims. Details from two or more of the embodiments may be combined with each other.

[0194] FIG. 1 illustrates an assembly line 1 which may be used for producing and filling composite cans (broadly, containers) with bulk solids according to the method as disclosed herein. The assembly line 1 is configured for assembling composite cans by forming a tubular body and attaching can components to the tubular bodies in a flow of intermediate cans. FIGS. 2a and 3 show an exemplary can 101, which may be produced on the assembly line 1 in FIG. 1. It is to be understood that the particular shape of the can 101 shown in FIG. 3 should not be considered limiting to the invention, as the assembly line 1 is suitable for the production and filling of cans of any useful shape or size and for the production of composite cans without such components which are disclosed herein as being optional.

[0195] The illustrated assembly line 1 comprises a number of machine stations or units 3-10 connected by conveyors 2a, 2b, 2c, 2d. In order from the beginning of the assembly line 1, the machine units are: a body forming station or unit 3, a filling station or unit 4, a gas box 5, a sealing station or unit 6, a cleaning station or unit 8, a can turning station or unit 9, a scoop insertion station or unit 10 and a lid attachment station or unit 7. A further conveyor 2e is arranged at the end of the assembly line 1 and is arranged to convey the produced composite cans from the lid attachment unit 7 and further e.g. to a packing apparatus (not shown).

[0196] Production of composite cans on the assembly line 1 is described below with reference to a single composite can. It is to be understood that while the assembly line 1 is run, multiple composite cans are continuously produced and are leaving lid attachment unit 7 at the end of the assembly line 1. As set out herein, the machine units of the assembly line 1 such as any can component attachment unit, may be configured to simultaneously process multiple intermediate cans such as 2, 3, 4, 5 or 6 intermediate cans. Exemplary can component attachment stations or units 405, 406 are shown in FIGS. 5, 6 and 7.

[0197] The assembly line 1 can thus include or be provided with a supply of body blanks, sealing members, reclosable lids, rims, and bottom plates, each as described further herein.

[0198] The body forming unit 3 includes: a body blank picking station 11, a body forming station 12, a top sealing station 13 and a top rim application station 14.

[0199] In the body blank picking station 11, a body blank 16 is picked from a pile of body blanks 16 and transferred to the body forming station 12. In the body forming station 12 a tubular body is formed by bending the body blank 16 and bringing two opposing edges of the body blank together in an end-to-end join, also known as a butt join. The join extends in a height direction H of the tubular body between a top end and a bottom end of the tubular body, as shown in FIG. 2a. The join is subsequently sealed by means of a sealing strip which is welded to the inner surface of the tubular body, whereby an intermediate can is formed. The sealing strip and the inner surface of the tubular body comprise a weldable polymer layer on the adjoining surfaces. The sealing strip is preferably welded to the inner surface of the tubular body by means of high frequency induction welding, as disclosed herein.

[0200] After forming the tubular body and applying the sealing strip, the intermediate can is transferred to the top sealing station 13 and the top opening at the top end of the tubular body is sealed by attaching a top sealing member across the top opening. The top sealing member is attached by welding a peripheral flange of the top sealing member to the inner surface of the tubular body. As disclosed herein, the top sealing member is can be a flexible component made from a laminate of one or more layers of thermoplastic polymeric material and the peripheral flange is created by folding an edge portion of the top sealing member out of the plane of the top sealing member and into alignment with the inner surface of the tubular body, however the top sealing member can be free from plastic material without departing from the disclosure. The top sealing member is taken from a magazine which is not visible in FIG. 1 and is applied at a distance from the top opening edge to allow for attachment of a top rim above the top sealing member. If the composite can comprises a scoop, a leaflet, or other supplementary item, the top sealing member may be applied at a sufficient distance from the top opening edge to allow the item to be accommodated in a space formed between the top sealing member and an inner surface of the reclosable lid.

[0201] After sealing of said top opening the top rim may be applied. The intermediate can with the applied top sealing member may then be transferred to the top rim application station 14 where the top rim is applied to the intermediate can by inserting at least a lower part of the top rim into the top opening, above the top sealing member. Preferably, the top rim is inserted into the tubular body such that an upper end edge of the top rim remains outside of the tubular body or is flush with the top end edge of the tubular body whereby the top rim protects the vulnerable carton edge of the tubular body and forms a rigid resting surface for the intermediate can during the subsequent process steps.

[0202] As illustrated in FIG. 1, the body forming unit 3 is enclosed in an external housing 20. A can turning arrangement may further be arranged inside the external housing 20 so that the intermediate can with the top rim attached may be turned upside down directly after rim application. Alternatively, the intermediate can is turned in a conventional turning apparatus placed downstream of the top rim application station 14. An example of a conventional turning apparatus is illustrated by the can turning unit 9, which is located downstream of the body forming unit 2. The can turning station or unit 9 operates by causing the intermediate can to topple over on an inclined conveyor.

[0203] After application of the top rim and turning the intermediate can upside down, the intermediate can is transferred to a first conveyor 2a and placed with the top rim resting on the conveyor 2a and a bottom opening at a bottom end of the tubular body facing upward in the vertical direction. The intermediate can is moved by the conveyor 2a to the filling unit 4 where it is filled with dry or moist goods through the bottom opening of the tubular body.

[0204] Subsequently, while still resting on the top rim, the filled intermediate can is moved by a second conveyor 2b to the gas box 5 where the filled intermediate can is subjected to treatment by a protective gas while the intermediate can is moved through the gas box 5. The gas box 5 is an optional part of the process equipment for carrying out the method as disclosed herein which may be used e.g. when the packaged goods is sensitive to oxygen and/or moisture. Furthermore, creating a protective gas atmosphere for the filled intermediate can may be made by other means, as set out herein. After leaving the gas box 5, the filled intermediate can is transferred to the sealing unit 6 on a third conveyor 2c. The third conveyor 2c moves through a gas tunnel which is tightly fitted to the wall of the sealing unit 6 at the inlet into the sealing unit 6, in order to maintain the protective atmosphere created in the gas box 5.

[0205] In the sealing unit 6, the bottom opening of the tubular body is sealed in a can sealing station 21 by attaching a bottom sealing member across the bottom opening, the attachment being made by welding a peripheral flange of the bottom sealing member to the inner surface of the tubular body at a distance from a bottom end edge of the tubular body. Accordingly, the bottom sealing member is applied in a manner corresponding to that of the top sealing member by folding a peripheral edge portion of the bottom sealing member into alignment with the inside wall of the tubular body before welding the facing surfaces of the bottom sealing member and the tubular body to each other. The sealing unit 6 preferably comprises a bottom plate application station 22 for application of a bottom plate after the bottom sealing member has been inserted in the tubular body and welded in place.

[0206] As is seen in FIG. 1, the sealing unit 6 is enclosed in an external housing 23, similar to the external housing 20 which encloses the body forming unit 3. By adapting the size and shape of the inlet and outlet ports 24, 25 of the external housing 23 to the size and shape of the intermediate cans produced on the assembly line 1, the ports 24, 25 may be kept generally sealed by the intermediate cans continuously passing through the ports 24, 25 during production. Thereby, it is possible to maintain a protective gas atmosphere inside the external housing 23 during the bottom sealing operation.

[0207] After filling, bottom sealing, and application of a bottom plate, the intermediate can is again turned to bring the top rim in an upward-facing position in the vertical direction.

[0208] In analogy with the first turning operation which is carried out after application of the top rim, the can turning arrangement may be part of the sealing unit 6 so that the intermediate can is turned directly after bottom sealing and bottom plate application. In the assembly line 1 which is shown in FIG. 1, the intermediate can is instead turned in a conventional turning unit 9 which is arranged downstream of the sealing unit 6.

[0209] In the example shown in FIG. 1, a cleaning unit 8 is arranged between the sealing unit 6 and the turning unit 9. In the cleaning unit 8, any product residue which may have escaped to the outside of the intermediate can during the previous process steps is removed by means of pressurized air. A cleaning unit 8 is optional to the assembly line as disclosed herein and may be particularly useful when the packaged goods is a powder or a particulate material with small-size particles or containing fragments which may cause dusting.

[0210] As set out herein, a scoop or other item may be placed above the top sealing member before finally closing the composite can by attaching the lid. As shown in FIG. 1, a scoop insertion unit 10 and/or other item insertion unit may be arranged in the process line, downstream of the location where the composite can has been turned with the top end facing upward. In the assembly line shown in FIG. 1, the scoop insertion unit 10 is placed after the turning unit 9.

[0211] The filled and sealed intermediate can is thereafter transported to the lid attachment unit 7 on the conveyor 2d and a reclosable lid is attached at the top end of the tubular body such that an inner surface of the reclosable lid is in direct contact with an upper surface of the top rim. As set out herein, the reclosable lid may be applied as part of a lid component, the lid component further comprising a frame structure. Preferably, the lid component is mechanically attached to the upper rim by a snap-fit connection.

[0212] The assembly line may further comprise quality control equipment and equipment for removing deficient intermediate composite cans and fully assembled composite cans from the flow of composite cans. Such quality control equipment may comprise detection equipment for detecting flaws in the intermediate cans or machine malfunctioning during production e.g. visual detection devices, an X-ray machine which may be placed after the lid attachment unit 7, etc. Furthermore, the quality control equipment may comprise can rejection stations which are commonly placed after one or more of the body forming unit 3, the filling unit 4, the sealing unit 6, the scoop insertion unit 10 and the lid attachment unit 7 to ascertain that any deficient composite cans are removed from the production line.

[0213] As disclosed herein, the composite cans are filled with dry or moist goods in the form of particles or pieces, granules, flakes, grain, etc. The goods flows into the composite can under the influence of gravity.

[0214] The composite can 201 shown in FIGS. 2a and 3 may be produced on the assembly line 1 in FIG. 1 and comprises a tubular body 203 having a tubular body wall 205. The body wall 205 extends in the height direction H of the can 201 from a bottom end edge 207 at a bottom end of the tubular body 203 to a top end edge 209 at a top end of the tubular body 203. The tubular body 203 has a top opening 211 at the top end and a bottom opening 213 at the bottom end.

[0215] A bottom sealing member 215 is positioned adjacent the bottom end of the tubular body 203 and covers the bottom opening 213. In this regard, the bottom sealing member 215 is positioned in the interior of the tubular body 203 sealably engaging the tubular body 203, the bottom sealing member 215 spaced away from each of the top end of the tubular body 203, the bottom end of the tubular body 203, and a top sealing member 227 as described further herein. The tubular body 203 has been formed by bringing together the side edges of a body blank end-to-end and sealing the join with a sealing strip 214, as set out herein.

[0216] The bottom end edge 207 is reinforced by a reinforcing bottom plate 217 which is applied to the inner surface of the body wall 205 and/or to a peripheral flange 216 of the bottom sealing member 215, between the bottom sealing member 215 and the bottom end edge 207. The bottom plate 217 is a molded plate comprising pulp fibers, such as softwood pulp fiber. In this regard, the bottom plate 217 can be free from plastic materials. The bottom plate 217 covers the entire bottom opening 213. In the illustrated embodiment, the bottom plate 217 has an outwardly directed flange 219 which covers the bottom end edge 207 of the tubular body 203 and engages the bottom end of the tubular body 203 to form a bottom edge of the can 201. The bottom plate 217 reinforces the bottom end edge 207, stabilizes the shape of the tubular body 203 and protects the bottom end edge 207 from mechanical deformation. The bottom plate 217 also serves as a protective barrier against water and other fluids which may be present on a surface on which the can 201 is placed. The bottom plate 217 delimits a downwardly open space between the bottom sealing member 215 and the bottom edge of the can 201, which may be used to accommodate stacking elements arranged at an upper end of another can when stacking two or more cans on top of each other.

[0217] The composite can 201 is provided with a closure arrangement comprising a lid 221 and a top rim 223 extending along the edge of the top opening 211. The lid 221 may comprise a planar inner sealing disc which seals against the top rim 223 when the composite can 201 is closed, as shown in FIG. 3. The can 201 is further provided with a fully or partly removable top sealing member 227 which is sealed to the body wall 205 along an upwardly folded peripheral flange 218. Accordingly, the top sealing member 227 is positioned in the interior of the tubular body 203 sealably engaging the tubular body 203, the top sealing member 227 spaced away from each of the top end of the tubular body 203, the bottom end of the tubular body 203, and the bottom sealing member 215.

[0218] The top rim 223 may form a closed loop, as seen in FIG. 2a.

[0219] The top rim 223 and/or the bottom plate 217 may be attached at a connecting portion of the top rim 223 and/or the bottom plate 217 to an end portion of the tubular body along an end edge of the tubular body. The connecting portion of the top rim 223 and/or the bottom plate 217 has a distal edge. The tubular body may be made from a laminate sheet material comprising a carton substrate layer and a thermoplastic welding layer. In some embodiments, the tubular body can be free from plastic materials and welding layers.

[0220] The tubular body may have a thermoplastic welding layer in a basis weight of at least g/m2, such as within the range of from 20 g/m2 to 160 g/m2, optionally 35 g/m2 to 140 g/m2, or 40 g/m2 to 120 g/m2 on the laminate sheet material. It has been found by the present inventors that such basis weight of the thermoplastic welding layer provides an enhanced welding with a rim comprising pulp fibers. Conventionally, the rim is a plastic rim and welding between the plastic rim and a paperboard container comprising a thermoplastic welding layer is therefore facilitated. However, if the thermoplastic welding layer has such basis weight an improved sealing, being durable and moisture resistant, between the tubular body and the rim according to the present invention may be achieved.

[0221] The thermoplastic welding layer may comprise or consist of a polyethylene layer.

[0222] The thermoplastic welding layer may comprise a metallic powder dispersed therein or metallised polymers.

[0223] A laminate body sheet material which may be used in a composite packaging container as disclosed herein may comprise one or more layers in addition to the mandatory structural carton substrate layer and the inner thermoplastic welding layer as disclosed below. As seen in order from the outside to the inside, the laminate body sheet material may have the following structure: [0224] a) an optional polymeric coating, such as a laquer, [0225] b) an optional printed and/or coloured layer [0226] c) a carton substrate layer [0227] d) an optional polymeric bonding layer, e.g. a polyethylene (PE) layer [0228] e) an inner thermoplastic welding layer, such as a polyethylene (PE) layer. The inner thermoplastic welding layer may consist of two or more sub-layers, such as a polyethylene (PE) layer and a low-density polyethylene (LDPE) layer. The sublayers may be coextruded to form the inside polymeric layer, or may be formed as separate films which are laminated together.

[0229] The tubular body is connected to the top rim 223 and/or the bottom plate 217 by welding the end portion of the tubular body to the connecting portion of the top rim 223 and/or the bottom plate 217. The distal edge of the connecting portion is located at a distance from the end edge of the tubular body of at least 4 mm, as seen in the longitudinal direction of the tubular body.

[0230] The lid 221, top rim 223 and the bottom plate 217 may each be a molded component comprising pulp fibers. In this regard, one or more of the lid 221, the top rim 223, and the bottom plate 217 can be free from plastic materials. The molded component may be constituted of from 95% to 100% of pulp fibers, such as softwood pulp fibers, optionally virgin softwood pulp fibers, optionally of from 98% to 100% of pulp fibers. Examples of such materials which have been developed for molding applications such as molded trays and blisters, shaped or embossed boxes, etc. are produced e.g. at Billerud Gruvn and sold as Billerud FibreForm. A similar material is the Advantage Formable paper available from Mondi.

[0231] The tubular body of the composite paperboard container may be made of a laminate sheet material comprising a carton substrate layer and an inner thermoplastic welding layer. The composite paperboard packaging container to which this disclosure relates is intended to store moisture-sensitive bulk solids, but is normally not intended to be stored in a cooled space, such as a refrigerator, and does therefore not need an outer polymeric resin layer such as polyethylene. The tubular body of this type of composite paperboard containers is however often provided with an outer coating composition, such as a varnish, to increase the wear resistance and to provide an aesthetically pleasing packaging container.

[0232] There is desire to provide packaging for sensitive goods such as food products with improved recyclability, without sacrificing durability or packaging safety for the packaged goods. However, since the top rim 223 is a molded rim comprising pulp fibers the structure may be less flexible and may also have a more irregular surface compared to a conventional plastic rim which may reduce the sealing tightness between the rim and the tubular paperboard body. Thereby, durability or packaging safety for packaged goods may be reduced since there could be a risk of air and/or moisture penetrating the space between the tubular body and the rim. It was however surprisingly found by the present inventor, that by providing a rim with a connecting portion extending at least 4 mm in the longitudinal direction from the end edge of the tubular body and welding the rim to the tubular body provided with an inner layer of a thermoplastic welding layer, a satisfying sealing tightness allowing packaging for sensitive goods such as food products could be achieved while yet providing a neat appearance at the bottom or upper container edge on an easily recyclable container. It has been found that a rim with a connecting portion extending at least 4 mm, in the longitudinal direction from the end edge of the tubular body, optionally of from 4 mm to 50 mm in the longitudinal direction from the end edge of the tubular body, optionally from 5 mm to 40 mm in the longitudinal direction from the end edge of the tubular body, provides an enhanced shape stability for the rim by means of the tubular body wall providing a support for the most fragile part of the rim, namely the connecting portion or connecting portions.

[0233] The rim may be an inner rim and the composite paperboard container may furthermore comprise a lid component. The lid component may be a molded lid component comprising pulp fibers, such as softwood pulp fibers, and may be made from the same material and in the same manner as the inner rim. The lid component may comprise a lid part and an outer rim part, the outer rim part and the lid part may be moulded in one piece and be connected to each other via a hinge portion. The outer rim part is connectable to the inner rim. The outer rim component may be mechanically connected to the inner rim, such as by a snap-on connection, a slide-in connection etc.

[0234] The rim may alternatively be part of a rim and lid component, wherein the rim part and the lid part of the rim and lid component may be moulded in one piece, the rim part being connected to the lid part via a hinge portion and the wherein the rim part is welded to the tubular body.

[0235] The rim may be connected either to the inner surface or to the outer surface of the tubular body via the first connecting portion. The first connecting portion is a circumferential connecting portion extending around the entire circumference of the tubular body. The first connecting portion is connected to the tubular body along the entire end portion, to the inner and/or to the outer surface of the tubular body.

[0236] The rim may be provided with a thermoplastic layer on a surface facing the tubular body. A thermoplastic layer provides the rim with a less irregular surface and, thus, enhances sealing and improves durability or packaging safety for the packaged goods. The rim can be provided without such thermoplastic layer without departing from the disclosure.

[0237] The top rim 223 defines a perimeter of an access opening which is smaller than the upper container body opening 211 as defined by the upper end edge 209 of the tubular body 203.

[0238] As set out herein, the top rim 223 is attached to an inner surface of the body wall 205 at the top opening 211. The top rim 223 has an extension in the height direction, H, of the composite can 201 and has a lower rim part facing towards the bottom sealing member 215 and an upper rim part facing away from the bottom sealing member 215. The top rim 223 extends around the full periphery of the top opening 211. The upper part of the top rim 223 protrudes upwards in the height direction, H, above the top end edge 209, whereby a part of the top rim 223 is arranged above the top end edge 209 in the height direction, H, of the composite can 201.

[0239] The top rim 223 can be joined to the inner surface of the body wall 205 by means of a weld seal extending around the top opening 211. The weld seal preferably extends continuously around the top opening 211 and is a sift-proof weld seal and is preferably also a moisture proof weld seal and most preferably a gas-tight weld seal.

[0240] As set out herein, the weld seal between the top rim 223 and the body wall 205 may be formed by supplying energy to heat and locally soften or melt one or more thermoplastic component in the top rim 223 and/or in a coating or film on the inner surface of the body wall 205 and by pressing the top rim 223 and the body wall 205 together in a direction perpendicular to the body wall 205. The temperature and pressure can be controlled and adjusted to form a strong and tight seal without damaging the welded components. The thermoplastic material used to create the weld seal may be provided by a partly thermoplastic top rim 223, by a thermoplastic film or coating on the inner surface of the body wall 205, or by thermoplastic material from both the top rim 223 and the body wall 205. The top rim 223 is preferably made from molded pulp fiber. By way of example, the surface of a top rim or bottom plate which is to be welded to the container body may be formed from a polymer composition having a lower softening and melting point than other parts of the rim. Moreover, an abutment surface on the top rim 223 may be formed from a resilient thermoplastic polymer. Any suitable welding technique may be used, such as ultrasonic welding or high frequency induction welding, with high frequency induction welding being preferred, as set out herein.

[0241] The top rim 223 and the body wall 205 can be joined without the use of thermoplastic materials without departing from the disclosure.

[0242] The lid 221 is a profiled part with a three-dimensional shape providing an upper outer surface of the lid 221. The lid may have an inner surface comprising a pattern of reinforcing ribs. The composite can may comprise a planar sealing disc which is applied over the inner surface of the lid 221. The sealing disc may be arranged to seal against the upper part of the top rim 223 when the composite can 201 is in the closed position as shown in FIG. 3. Alternatively, an inner sealing surface of the lid may be formed integral with the lid. Further alternatives for creating a sealing closure between the top rim 223 and the lid 221 is by arranging a sealing ring on the inner surface of the lid 221 or by application of a sealing coating on selected portions of the inner surface of the lid and/or on the top rim 223.

[0243] The lid 221 is connected by a hinge 229 to a frame structure 230, the lid 221 and the frame structure 230 together forming a lid component 231. The hinge 229 is a live hinge, formed integrally with the lid 221 and the frame structure 230 as a flexible connection between the lid 221 and the frame structure 230. As set out herein, the illustrated hinge is only intended as a non-limiting example and it should be understood that any other type of functional hinge may be used for a connection between the frame structure and the lid. Moreover, the lid may be of the removable kind, without any permanent connection to the frame structure. The lid component 231 may be made of molded pulp fiber material, preferably softwood pulp fiber material.

[0244] The frame structure 230 is applied to the composite can 201 at the top end edge 209 and is mechanically attached to the top rim 223 by a snap-on connection. The frame structure 230 is attached to the top rim 223 after the top rim 223 has been welded to the inner surface of the body wall 205. The frame structure 230 is applied to the top rim 223 by pressing the frame structure 230 down over the upper edge of the top rim 223 until the frame structure 230 locks in place on the top rim 223 by means of mating snap-in features on the top rim 223 and the frame structure 230. When the frame structure 230 has been attached to the top rim 223, it can only be removed again by breaking or damaging the snap-in connection between the top rim 223 and the frame structure 230.

[0245] An interior compartment 208 containing the packaged goods is delimited by the top sealing member 227 at the upper end of the tubular body 203 and by the bottom sealing member 215 at the bottom end of the tubular body 203.

[0246] In order to gain a first access to the packaged goods in the interior compartment 208, a user needs to open the lid 221 and expose the packaged goods by fully or partly removing the top sealing member 227. The top sealing member 227 may be arranged to be peeled away from the wall 205 of the tubular body 203 or may be arranged with means for breaking the top sealing member 227 so that it can be at least partly removed through the access opening. Such means may be in the form of one or more predefined weakenings, such as perforations or a cut partly through the top sealing member 227. When the top sealing member 227 is of the tear-open type, a narrow edge part of the top sealing member 227 may be left at the inner surface of the body wall 205. Any such remaining part of the top sealing member 227 should preferably not be so large so that it extends into and restricts the access opening which is defined by the inner perimeter of the top rim 223.

[0247] Once the top sealing member 227 has been removed, it is sufficient to open the lid 221 in order to gain access to the packaged goods in the interior compartment 208 through the access opening. As is seen in FIG. 2a, which reveals the inside of the top rim 223, the area of the access opening is defined by an inner perimeter or inner contour of the top rim 223. As the top rim 223 is applied on the inner surface of the body wall 205 and adds thickness to the body wall in an inward direction, the area of the access opening is always smaller than the area of the top opening 211 of the tubular body 203.

[0248] When the composite can 201 is open, a desired quantity of the packaged goods may be removed from the composite can 201 through the access opening either by means of a scoop or by pouring. The scoop may preferably be provided together with the composite can 201. The scoop may initially be placed on the top sealing member 227, may be removably attached to the inner surface of the lid 221 which inner surface may be constituted by the above-mentioned sealing disc. When placed on the top sealing member 227, the scoop may be packaged in a protective wrap, such as a bag of paper or plastic. A further alternative is to attach a scoop to the top rim 223 e.g. by placing the scoop head in a scoop holder 240 provided on the top rim 223 as shown in FIG. 2a. In the illustrated embodiment, the scoop holder 240 also serves as a scraper bar for levelling off excess scooped-up material from the scoop. An example of a scoop 280 is shown in FIG. 2b. The scoop 280 has a scoop head 281 and a scoop handle 282. Generally, scoops 280 to be inserted into an intermediate can during manufacturing of a composite can as disclosed herein are arranged in a stack, e.g. as shown in FIG. 2b with the scoop heads 281 nesting inside each other. In order to facilitate stacking of scoops 280 with planar handles 282 a proximal end of the handle 282 may be provided with a stack stabilization arrangement 284. The stack stabilization arrangement 284 allows stacking of identical scoops 280 inside each other and facilitates keeping the stack 283 of scoops together, simplifying storing and handling of the scoops 280 and loading of the scoops into a scoop insertion unit 10, as shown in FIG. 1.

[0249] Advantageously the scoop head 281 has a tapering shape to allow she scoops 280 to fit snugly inside each other in an efficient and space saving manner.

[0250] As an alternative to stacking the scoops 280 with the scoop heads 281 and the scoop handles 282 arranged in the same direction, the scoops 280 may be stacked in alternating opposite directions as known in the art.

[0251] It is to be understood that the scoop 280 which is shown in FIG. 2b constitutes only one example of a suitable scoop configuration and that scoops having differently shaped scoop heads, differently shaped handles, different proportions between the scoop head and the scoop handle, etc. may be used in the composite cans as disclosed herein. The scoop may further have provisions for additional stack stabilization and/or for improving retention of the scoop 280 in a scoop holder. By way of example, the scoop head may comprise a thin snap-in ridge which serves to releasably lock the scoop head in a desired position in the scoop holder. Such additional fastening element for the scoop head may prevent the scoop head from inadvertently falling out of the scoop holder, and may also serve to prevent the scoop handle from hanging down into the composite can.

[0252] The closure arrangement as shown on the composite can 201 in FIGS. 1 and 2a with a top rim 223 directly attached to the inner surface of the body wall 205 and a lid component 230 comprising a lid 221 and a frame structure 230 provides a tight closure between the lid 221 and the tubular body 203. When the lid 221 is closed on the composite can 201, the upper edge of the top rim 223 may abut against the above-mentioned sealing disc and creates a seal between the top rim 223 and the lid 221.

[0253] In order to keep the lid 221 secured in the closed position between dispensing occasions, the closure arrangement of the composite can 201 may further comprise a locking arrangement 245, as seen in FIGS. 2a and 3. The locking arrangement 245 may comprise first and second mating locking elements, e.g. a female locking element such as a groove arranged on the lid 221 and a male locking element such as a rib arranged on a locking member 246 arranged on the frame structure 230. The locking member 246 is hingedly connected to the frame structure 230, such as by means of a live hinge 249 formed integrally with the frame structure 230 and the locking member 246.

[0254] A locking arrangement 245 of this type is closed by moving the locking member 246 upward and inward over the lid 221 to a position where the locking elements come into mating engagement. The locking arrangement 245 is opened by pulling at the locking member 246 until the connection between the locking elements is released and turning the locking member 246 downward at the hinge 249. When the locking member 246 is in the closed position with the first and second locking elements engaging with each other, the lid 221 and the frame structure 230 are firmly clamped together whereby the top rim 223 seals tightly against the above-mentioned sealing disc on the inner surface of the lid 221, or against a sealing ring or sealing surface arranged on the inside of the lid 221.

[0255] As best shown in FIG. 3, the lid component 231 is provided with a lid component stacking step 251 and a can stacking step 252. As shown in the figures, the stacking steps 251, 252 may extend across the locking member 246.

[0256] The lid component stacking step 251 is arranged to enable stacking lid components 231 on top of each other in stacks which can be loaded into a lid attachment unit. The can stacking step 252 is arranged for enabling stacking of composite cans 201 on top of each other.

[0257] An inset gripping area 265 may be arranged in the lid 221 at the free end portion of the locking member 246, opposite the hinge 249. Thereby, the locking member 246 can be easily accessed and while the locking member 246 when in the closed position is shielded from inadvertent release.

[0258] A composite can 201 as shown in FIGS. 2a and 3 may be produced and filled on an assembly line such as that shown in FIG. 1.

[0259] As set out herein, the composite cans as disclosed herein are produced in the following order: forming a tubular body, applying a top sealing member and a top rim to the tubular body, turning the tubular body upside down, filling the tubular body with dry or moist goods through the bottom opening of the tubular body, closing the bottom opening of the tubular body, applying a bottom plate to the tubular body, turning the sealed can so that the top sealing member again faces upward and finally applying a lid or a lid component to the top end of the tubular body.

[0260] FIGS. 4-7 show equipment which may be used for the application of can components in a top sealing station 13, a top rim application station 14, a sealing unit 6 and a bottom plate application station 22 of an assembly line 1 as shown in FIG. 1.

[0261] With reference to FIGS. 2a and 3, the bottom sealing member 215, the bottom plate 217, the top rim 223 and the top sealing member 227 are examples of can components for which the equipment in FIGS. 4-7 may be used.

[0262] With reference to FIG. 4, a can sealing station or unit 401 which may be the sealing unit 6 in FIG. 1 is shown.

[0263] Intermediate cans 403 are transported through the can sealing unit 401 in a running direction R. Transport means 402 comprising a feeding arrangement 411 in the form of two feed screw members arranged at respective opposite sides of the intermediate cans 403, whereof only one of the feed screw members is visible in FIG. 4, a main conveyor member 413, a movable gripping arrangement 415, and an outlet conveyor member 419. The outlet conveyor member 419 is arranged downstream of the can sealing unit 401 and a stationary sliding plate 421 is arranged downstream of the outlet conveyor member 419 at the outlet of the can sealing unit 401. Further details of a useful transport arrangement are described in WO 2013/009226 A1, to which document reference is made.

[0264] A can sealing station 405 is located downstream of the feeding arrangement 411 and a bottom plate application station 405 is located downstream of the can sealing station 405. The movable gripping arrangement 415 move the intermediate cans 403 to the sealing station 405 where bottom sealing members 427 are attached by welding to the inside of the tubular body wall of the intermediate cans 403, as illustrated by FIG. 8. The intermediate cans 403 are then moved to the bottom plate application station 405, where bottom plates 417 are applied, e.g. as shown in FIGS. 5 and 6 As illustrated in FIGS. 4-6 a plurality of bottom sealing members and bottom plates 417 may be attached simultaneously to a plurality of corresponding intermediate cans 403, in order to increase the running speed of the can sealing station 401. In the shown embodiment, four bottom sealing members and four rims are attached at the same time to respective intermediate cans 403. Alternatively, the bottom sealing members, rims or other can components as disclosed herein may be attached in groups of any other number than four, e.g. two, three, six, eight or ten, at the same time, or may be sequentially attached to the cans.

[0265] The transport means 402 and the can sealing station 401 may be encased in an external housing 20, 23 as shown in FIG. 1. The external housing 20, 23 is adapted to protect the can sealing station 401 and/or to provide and maintain a protective gas atmosphere inside can sealing station 401. The protective gas may e.g. be nitrogen, carbon dioxide or a mixture of nitrogen and carbon dioxide.

[0266] Degassing of the intermediate can may be performed concurrently with filling the intermediate can in a filling unit 4 as shown in FIG. 1. The degassing may comprise supplying a protective gas to the flow of material to be contained in the can during filling. The protective gas may be blown into the flow of material before the material reaches the can. If the material is treated with protective gas during filling, the intermediate cans 403 are preferably conveyed to a can component applicator such as the can sealing station 401 arranged downstream of the filling unit 4, while maintaining the modified gas atmosphere, e.g. by moving the cans through a tunnel filled with protective gas as illustrated by the covered conveyor 2c between the gas box 5 and the sealing unit 6 in FIG. 1. Alternatively, filled intermediate cans 403 may be introduced in a vacuum chamber to draw off air, whereafter the cans are subjected to a modified gas atmosphere and the bottom sealing member is applied.

[0267] FIGS. 5 and 6 illustrate an attachment station or unit 505 for attaching a can component such as a bottom plate 517 to an intermediate can 503. The attachment station or unit 505 comprises a retaining device 523, a supporting device 525, a positioning device 528 and a transfer plate 529.

[0268] An example of a transfer plate 529 is illustrated in FIG. 7. The transfer plate 529 extends in a first direction x, parallel to the running direction R of a can component applicator of which the attachment station or unit 505 forms part, and a second direction y perpendicular to the first direction x. The transfer plate 529 comprises a cavity portion 531 with at least one through-going transfer cavity 533 which is adapted to receive and hold the can component, in this case a bottom plate 517 during transfer of the can component into alignment with an end of the intermediate can 503. The transfer cavity 533 has a first open area A1 and is sized and configured such that the can component can be fit into the transfer cavity 533 and be retained therein during transfer to the intermediate can 503.

[0269] As an alternative, in particular when the can component is a sheet form can component such as a top sealing member or a bottom sealing member, the transfer plate 529 may be omitted such that the can component is placed directly on top of the retaining device 523.

[0270] In order to fit and hold the can component in the transfer cavity 533, the shape of the transfer cavity 533 is made to correspond to the shape of the can component.

[0271] In case of a can component including an edge portion which is to be folded to create a peripheral flange before or during insertion of the can component in the can, as is the case in a bottom sealing member or a top sealing member, the first open area A1 of the transfer cavity 533 may be smaller than the surface area of the can component before folding. The area difference corresponds to the area of the portion of the can component which forms the peripheral flange. Such a folded flange is typically band shaped and may have a width in the range of from 1 to 10 mm, such as in the range of from 2 to 5 mm. See FIG. 8. Accordingly, a folded peripheral flange on a sheet form can component such as a top sealing member or a bottom sealing member may be created by pressing the can component down through a transfer cavity 533 having a smaller cross-sectional area than the can component, thereby forcing the can component to fold at the edge of the transfer cavity in order to be accommodated within the first open area A1 of the transfer cavity.

[0272] A wall of the transfer cavity 533 may comprise holding elements 534 adapted to hold the can component in the transfer cavity 533. See FIG. 7. Such holding elements 534 are especially useful for a loop shaped can component such as a top rim which does not cover the first open area A1 of the transfer cavity 533. When the can component is a sheet form can component, the holding elements 534 may be omitted.

[0273] In the embodiment illustrated in FIG. 7, there are four holding elements 534 each adapted to hold a corresponding side of a loop shaped can component having a substantially rectangular or square shape. In the illustrated embodiment the holding elements 534 are arranged such that they will hold the can component at a centre of each side. It would be feasible to use one, two, three, four or more such holding elements 534. The holding elements 534 may be resiliently compressible, e.g. due to material properties or by being biased by a spring. Alternatively, or additionally, the can component such as a rim may itself be resiliently deformable, e.g. due to material properties. The holding elements 534 may be utilized to compensate for tolerances regarding the dimensions of the can component and/or the transfer cavity 533. Furthermore, the holding elements 534 may be used to temporarily press one or more sides of the can component inwards, causing the can component to assume a reduced cross-section whereby it is easier to insert into the intermediate can 503. Thereby, the risk of damaging the vulnerable carton edges of the tubular body of the intermediate can 503 during insertion of a rim-type can component can be eliminated or at least considerably reduced.

[0274] As illustrated in FIGS. 5, 6 and 7, the transfer plate 529 may comprise a cover portion 535 which is at least as large as, or substantially as large as, the first open area A1 of the transfer cavity 533. The cover portion 535 is arranged adjacent to the cavity portion 531 as seen in the second direction y. The cover portion 535 has a minimum extension y1 in the second direction y, which is at least 1.0 times a maximum extension y2 in the second direction y of the area A1 of the transfer cavity 533, preferably at least 1.2 times, more preferably at least 1.4 times. The use of a transfer plate having a cover portion 535 is advantageous to prevent excessive escape of protective gas from inside a can component applicator while the can component is being placed in the transfer cavity 533 and transported into alignment with the intermediate can 503. When the can component is instead a sheet form component, it may be picked by a suction member and placed in alignment with an opening in the intermediate can 503 in which the sheet form can component is to be inserted. As set out herein, the transfer plate 529 may be omitted and the sheet form can component may be placed directly on top of the retaining device 523.

[0275] After application in the intermediate can 503, the sheet form can component covers the can opening and prevents gas from escaping out through the intermediate can 503. If the can component applicator is operated without a protective atmosphere or if some loss of protective gas can be tolerated, a transfer plate without a cover portion may be used when applying the can component. Furthermore, the attachment unit 505 may comprise an internal housing 547, as indicated by point-dashed lines in FIGS. 5 and 6. The internal housing 547 is located inside an external housing 20, 23 as shown in FIG. 1 and is arranged to provide enhanced protection against escape of protective gas from the space above the positioning cavity 537 of the retaining device 523.

[0276] In order to facilitate placing a can component into the transfer cavity 533 of the transfer plate 529, indentations 536 may be provided as illustrated in FIG. 7. The indentations 536 allow space for gripping members 544a, 544b, 544c, 544d which are arranged to move the can component from a magazine 543 into the transfer cavity 533. See FIGS. 5 and 6. If holding elements 534 are provided in the transfer plate 529, the indentations 536 are preferably located such that they do not interfere with the holding elements 534. Thus, the indentations 536 may be located in the corners of the transfer cavity 533. Such gripping members 544a, 544b, 544c, 544d with their corresponding indentations 536 are especially useful when the can component forms a loop, which comprises an inner volume filled by gas, e.g. air, such as a bottom rim.

[0277] If the can component is a sealing member, or a lid, the can component may instead be placed into the transfer cavity 533 by gripping means such as one or more suction cups. In such case, the indentations 536 may be omitted. However, suction cups are not suitable when the can component is of the loop type, such as a top rim.

[0278] In the illustrated embodiment, which may e.g. be a bottom plate application station 22 of an assembly line 1 as shown in FIG. 1, there are four cavity portions 531 arranged in a row as seen in the first direction x. Each cavity portion 531 comprises a respective transfer cavity 533 and is arranged together with a corresponding respective cover portion 535.

[0279] The retaining device 523 retains the intermediate can 503 while the can component, illustrated as the bottom plate 517, is being attached to the intermediate can 503. The retaining device 523 comprises at least one through-going positioning cavity 537 with a second open area A2 corresponding to the first open area A1 of the transfer cavity 533. The positioning cavity 537 is adapted to receive a portion of the intermediate can 503. If having a cover portion 535, the size and shape of the cover portion 535 of the transfer plate 529 is selected, such that the cover portion 535 can be brought to cover, or at least substantially cover, the second open area A2 of the positioning cavity 537.

[0280] The supporting device 525 is arranged to support the intermediate can 503 and to position the intermediate can 503 in the retaining device 523.

[0281] The positioning device 528 is arranged to position the can component in the intermediate can 503 as illustrated by FIGS. 5 and 6. Hence, the positioning device 528 is aligned with the positioning cavity 537 as seen in a vertical direction z. The positioning device 528 is vertically adjustable allowing insertion of the can component into the intermediate can 503 to a desired preselectable attachment position. As described herein with reference to FIG. 8, the positioning device 528 may be caused to expand in a radial direction of the positioning cavity 537 and to press a vertically extending portion of the can component in a direction towards a wall of the positioning cavity 537, whereby the can component is pressed against an inside of the tubular wall of the intermediate can 503 which is placed in the positioning cavity 537.

[0282] In the illustrated embodiment the attachment unit 505 is arranged to simultaneously process four intermediate cans 503. The transfer plate 529 comprises four cavity portions 531 arranged in a row as seen in the first direction x of the attachment unit 505. In a corresponding way, the retaining device 523 comprises four positioning cavities 537, and the supporting device 525 is adapted to support four intermediate cans 503 and to position the intermediate cans 503 in the respective positioning cavities 537 of the retaining device 523. In addition, the attachment unit 505 comprises four positioning devices 528, aligned with the positioning cavities 537, such that each positioning device 528 is associated with a respective positioning cavity 537. It is to be understood that the attachment unit may be arranged for simultaneous processing of any suitable number of intermediate cans, as set out herein.

[0283] The transfer plate 529 is movable between a first position shown in FIG. 5 and a second position shown in FIG. 6. In the first position, the transfer plate 529 has been moved in the y-direction such that the transfer cavity 533 has been shifted away from the retaining device 523. In this position, the transfer plate 529 is arranged to receive the can component in the transfer cavity 533. If the transfer plate 529 is provided with a cover portion 535, as shown in FIGS. 5-7, the cover portion 535 in the first position covers or substantially covers the second open area A2 of the positioning cavity 537, as illustrated in FIG. 5 during application of the can component in the transfer cavity 533. Thereby, loss of protective gas through the positioning cavity 537 may be minimized, or preferably eliminated.

[0284] In the second position, as shown in FIG. 6, the transfer plate 529 has been moved in the y-direction whereby the transfer cavity 533 has been brought into alignment with the positioning cavity 537 of the retaining device 523 and the positioning device 528 which is arranged above the positioning cavity 537. When the transfer plate 529 is in the second position, the positioning device 528 may push a can component located in the transfer cavity into the intermediate can. The can component, such as the bottom plate 517 shown in FIGS. 5 and 6, is pushed from the transfer cavity 533 in the transfer plate 529 into the intermediate can 503 by downward movement of the can component in the z direction through the transfer cavity 533 and at least partly through the positioning cavity 537 of the retaining device 523.

[0285] The retaining device 523 may comprise a welding station or unit 539 as disclosed herein. The welding unit is preferably a high frequency induction welding unit and is arranged around the positioning cavity 537. The welding station or unit 539 is adapted to weld the can component to the intermediate can 503, and comprises a coil extending around the positioning cavity 537. As the positioning device 528 may be caused to expand in a radial direction of the positioning cavity 537 as set out herein, the can component can be pressed against the welding unit 539.

[0286] As is shown in FIGS. 5 and 6, the bottom plate 517 or other can component may be placed in the transfer cavity 533 of the transfer plate 529 by means of an optional can component supplier 541 comprising at least one gripping station or unit 542. A pile of can components, e.g. bottom plates 517, may be stored in a magazine 543. The number of piles in the magazine 543 and the number of gripping units 542 correspond to the number of transfer cavities 533 in the transfer plate 529. The gripping unit 542 is able to grip a single can component, here the bottom plate 517, move it from an opening 545 in the magazine 543 and place it in the corresponding transfer cavity 533. As an example, four single can components are gripped at the same time. The gripping unit 542 comprises four gripping members 544a, 544b, 544c, 544d, which grip at the corners of the bottom plate 517. The positions of the gripping members 544a, 544b, 544c, 544d correspond to the positions of the indentations 536 of the transfer plate 529. As set out herein, such gripping members 544a, 544b, 544c, 544d with their corresponding indentations 536 are especially useful when the can component is not a sheet form element such as a bottom sealing member, an internal sealing member, or a top sealing member, but instead forms a loop, such as a top rim.

[0287] FIG. 8 illustrates a positioning device 828 as disclosed herein. The positioning device 828 may be used as a positioning device 528 of an attachment unit 505 as illustrated in FIGS. 5 and 6 or may be used for positioning of a can component in any attachment unit used for attachment of a can component inside a tubular can body. Hence, the positioning device may be used for placing can components in a tubular body with or without the concurrent use of a transfer plate.

[0288] FIG. 8 illustrates a top sealing member 827 which is in the process of being placed in an intermediate can 803. As can be gleaned from FIG. 8, the top sealing member 827 has a larger cross-sectional area than the inner cross-sectional area of the intermediate can 803. When placed in the intermediate can 803, an edge portion 833 of the top sealing member 827 will be folded upwards, such that it conforms to an inner surface of the can wall 805. The illustrated top sealing member 827 is a foldable member, such as a laminate of plastic films, a plastic film, a paper sheet, a paper/plastic laminate, or the like. Such foldable members can be devoid of plastic material without departing from the disclosure. Can components such as top sealing members and bottom sealing members may alternatively be pre-formed with a sealable edge portion extending perpendicular to a main plane of the of the can component. In such case, no folding of the edge portion is needed when inserting the can component into the tubular can body.

[0289] The positioning device 828 comprises a base plate 849 comprising or being constituted by a rigid material such as metal or a composite material, and a plunger skirt 851 comprising a resiliently deformable material, e.g. rubber or plastics. The plunger skirt 851 is located on top of the base plate 849, such that it at least partly covers an upper surface of the base plate 849 which upper surface is opposite a lower footprint surface 853 of the base plate 849.

[0290] The footprint surface 853 is configured to face towards the can component, here a top sealing member 827, during application of the can component in the intermediate can 803. The footprint surface 853 of the base plate 849 has a circumferential edge 855 which in the illustrated example has a substantially polygonal shape. However, it is to be understood that the footprint surface may have any other suitable shape adapted to the cross-sectional shape of the composite can which is being produced. In the illustrated example, the substantially polygonal shape is a substantially square shape which comprises four side edge portions which are connected by outwardly rounded corner portions. In the illustrated embodiment, each side edge portion is slightly inwardly curved. Thereby, the circumferential edge 855 of the footprint surface 853 of the base plate 849 with the inwardly curved side edge portions deviates from the cross-sectional shape or footprint of the produced composite can. Alternatively, the base plate of the positioning device may have the same footprint as that of the intermediate can 803, with straight side edge portions between curved corner portions.

[0291] It may be advantageous to arrange a curved side edge portion at least on the side of the base plate 849 which during insertion of the can component will be facing the sealing strip 814 covering the join in the tubular body 805. The sealing strip 814 makes the tubular wall 805 of the intermediate can 803 locally thicker and also constitutes a bending line where the tubular wall 805 tends to bend causing the tubular wall 805 to deviate from a desired planar or near-planar shape. A slightly inwardly curved side edge portion of the circumferential edge of the footprint surface of the base plate, allows the base plate to move along the join without damaging the sealing strip or the can body material when the positioning device 828 inserts the can component 827 into the intermediate can 803.

[0292] The plunger skirt 851 is transformable between an unexpanded state and an expanded state by relative movement in relation to the base plate 849.

[0293] In the unexpanded state of the plunger skirt 851, the shape of the outer contour of the plunger skirt 851 corresponds to that of the base plate 849. Hence, in the unexpanded state, the plunger skirt 851 has the same or substantially the same footprint as the base plate 849.

[0294] When seen in relation to the base plate 849, the outer circumference 861 of the plunger skirt 851 is located at or on the circumferential edge 855 of the base plate 849. Preferably, the outer circumference 861 of the plunger skirt 851 coincides with the circumferential edge 855 of the footprint surface 853 of the base plate 849 or is located slightly inside the circumferential edge 855 of the footprint surface 853 of the base plate 849 when the plunger skirt 851 is in the unexpanded state.

[0295] In the expanded state of the plunger skirt 851, the footprint which is delimited by the outer circumference 861 of the plunger skirt 851 is larger than in the unexpanded state of the plunger skirt 851.

[0296] During transformation to the expanded state, pressure is applied to the plunger skirt 851 from above. Thereby, the side edge portions of the plunger skirt 851 are stretched between the corners and any curved side edge portion is thereby straightened out. By selecting the shape and material properties of the plunger skirt 851, a desired change of shape during transformation may be obtained.

[0297] In the expanded state of the plunger skirt 851, the outer circumference 861 of the plunger skirt 851 is located at least partly outside of the corresponding circumferential edge 855 of the base plate 849. By transforming the plunger skirt 851 to the expanded state, it may be brought into contact with an edge portion 833 of the top sealing member 827 and be caused to press the edge portion 833 of the top sealing member 827 against the inside of the body wall 805.

[0298] If the can component attachment unit is provided with a transfer plate 529 comprising holding elements 534 as disclosed herein exerting an inwardly directed force on the can component, the plunger skirt 851 may contribute to press the can component back in a radial direction in case the can component does not spring back sufficiently itself from a deformed configuration imparted on the can component by the holding elements 534.

[0299] The positioning unit shown in FIG. 8 comprises a first piston 871 and a second piston 873 which is coaxial with the first piston 871. The pistons 871, 873 extend in an axial direction A, coinciding with the vertical direction z of the attachment unit 505, see FIGS. 5 and 6. The base plate 849 is attached to an end portion of the first piston 871, such that the footprint surface 853 is perpendicular to the axial direction A. The plunger skirt 851 is attached to an end portion of the second piston 873. The first and second pistons 871, 873 are configured to be moved in the axial direction A both together as a single unit, and as separate elements, independently of each other.

[0300] During displacement of the positioning device 828 into the intermediate can 803, the plunger skirt 851 remains in the unexpanded state until the can component 827 has been moved to the attachment position. When the can component 827 has reached the attachment position, the plunger skirt 851 is transformed to the expanded state by moving the end portion of the second piston 873 closer to the end portion of the first piston 871 thereby pressing an edge portion of the plunger skirt 851 radially outward.

[0301] The outer circumference 861 of the plunger skirt 851 presses the can component 827 against the inside of the body wall 805 of the intermediate can 803 which is placed in the positioning cavity. The edge portion of the outer circumference of the plunger skirt 851 which in the expanded state of the plunger skirt 851 is arranged to be in contact with and exert pressure on the can component, may have a contact surface which in the non-expanded state of the plunger skirt is slightly tilted with respect to the vertical direction of the positioning device.

[0302] In order to further improve contact between the can component and the can body material in the corner portions, thickened corner portions may be arranged on the upper surface of the base plate, i.e. on the surface opposite the footprint surface of the base plate. The thickened corner portions form raised areas on the upper surface of the base plate and serve to force the plunger skirt to move further out, exerting an increased pressure on the applied can component and improving contact between the can component and the tubular body. Thereby, a join formed between the can component and the corner portions of the tubular can body may be improved. In particular, an increased pressure in the corner portions of the tubular body may aid in creating a tight seal between the body material and a sheet form can component. Excess material present at the corner portions of sheet form can components, such as a bottom sealing member or a top sealing member, will generally wrinkle at the corners of the can as the can component is folded and aligned with the tubular body wall. In such case, an increased pressure created at the corner portions of the tubular body would compress the wrinkles and would contribute to the formation of a good functional bond, such as a thermo-weld between the body material and the sheet material in the can component. When using a thermo-welding process for bonding the can component to the wall of the tubular can body, at least one and preferably both of the can component and the tubular wall comprise a thermoplastic material in a sufficient amount to create a functional bond. However, and as described herein, such bonding can be achieved without the use of plastic materials without departing from the disclosure.