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SE505571C2 - Methods and apparatus for longitudinal joint sealing with induction heat of a packaging material of polymer coated metal sheet - Google Patents

Methods and apparatus for longitudinal joint sealing with induction heat of a packaging material of polymer coated metal sheet

Info

Publication number
SE505571C2
SE505571C2 SE9504566A SE9504566A SE505571C2 SE 505571 C2 SE505571 C2 SE 505571C2 SE 9504566 A SE9504566 A SE 9504566A SE 9504566 A SE9504566 A SE 9504566A SE 505571 C2 SE505571 C2 SE 505571C2
Authority
SE
Sweden
Prior art keywords
inductor
longitudinal joint
induction heat
joint sealing
coated metal
Prior art date
Application number
SE9504566A
Other languages
Swedish (sv)
Other versions
SE9504566D0 (en
SE9504566L (en
Inventor
Anders Hilmersson
Original Assignee
Tetra Laval Holdings & Finance
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tetra Laval Holdings & Finance filed Critical Tetra Laval Holdings & Finance
Priority to SE9504566A priority Critical patent/SE505571C2/en
Publication of SE9504566D0 publication Critical patent/SE9504566D0/en
Priority to PCT/SE1996/001704 priority patent/WO1997022524A1/en
Priority to AU12187/97A priority patent/AU1218797A/en
Publication of SE9504566L publication Critical patent/SE9504566L/en
Publication of SE505571C2 publication Critical patent/SE505571C2/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
    • B29C66/7232—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer
    • B29C66/72321—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer consisting of metals or their alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3604—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint
    • B29C65/3644—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a ribbon, band or strip
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3604—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint
    • B29C65/3656—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a layer of a multilayer part to be joined, e.g. for joining plastic-metal laminates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3668—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special induction coils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3672—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the composition of the elements heated by induction which remain in the joint
    • B29C65/3676—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the composition of the elements heated by induction which remain in the joint being metallic
    • B29C65/368—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the composition of the elements heated by induction which remain in the joint being metallic with a polymer coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43—Joining a relatively small portion of the surface of said articles
    • B29C66/432—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms
    • B29C66/4322—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms by joining a single sheet to itself
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/49—Internally supporting the, e.g. tubular, article during joining
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2795/00—Printing on articles made from plastics or substances in a plastic state
    • B29C2795/002—Printing on articles made from plastics or substances in a plastic state before shaping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/36—Bending and joining, e.g. for making hollow articles
    • B29C53/38—Bending and joining, e.g. for making hollow articles by bending sheets or strips at right angles to the longitudinal axis of the article being formed and joining the edges
    • B29C53/40—Bending and joining, e.g. for making hollow articles by bending sheets or strips at right angles to the longitudinal axis of the article being formed and joining the edges for articles of definite length, i.e. discrete articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832—Reciprocating joining or pressing tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Package Closures (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Closing Of Containers (AREA)
  • General Induction Heating (AREA)

Abstract

A longitudinal joint sealing with induction heat of a packaging blank (1) of polymer lined metal plate is accomplished by means of an inductor (2) for application against a joint, formed by an upper member and a lower member. For obviating burning of decoration on the upper member the return current of the inductor is conducted via the lower member.

Description

W Ü 20 25 30 35 sos 571 'i ¿ fig 4 är en ändvy från vänster av anordningen enligt fig 3, fig 5 är en förenklad sektion längs linjen V-V i fig 3 samt fig 6 är en vy uppifrån i mindre skala av en dorn för användning tillsammans med den i fig 1-5 visade induktor- balken. Fig. 4 is an end view from the left of the device according to Fig. 3, Fig. 5 is a simplified section along the line VV in Fig. 3 and Fig. 6 is a top view on a smaller scale of a mandrel for use together with the inductor beam shown in Figs. 1-5.

Beskrivning av föredragna utföringsformer Ett stympat koniskt förpackningsämne 1 skall med ut- gångspunkt från ett plant ark ges den på ritningarna visade koniska formen och pá det sätt som är föremål för uppfin- ningen förses med en längdskarv, varpå det kan utrustas med botten och lock på ett här ej visat och beskrivet sätt.Description of preferred embodiments A truncated conical packaging blank 1 is to be given the conical shape shown in the drawings on the basis of a flat sheet and in the manner which is the subject of the invention is provided with a longitudinal joint, whereupon it can be equipped with a bottom and lid a way not shown and described here.

Förpackningsämnet l är företrädesvis framställt av aluminium med en tjocklek av 50-300 pm, exempelvis 85 pm.The packaging blank 1 is preferably made of aluminum with a thickness of 50-300 μm, for example 85 μm.

Aluminiumytan är åtminstone på ena sidan belagd med en för- seglingsbar polymer, exempelvis en polyester, men ofta på båda sidorna.The aluminum surface is coated on at least one side with a sealable polymer, for example a polyester, but often on both sides.

För att åstadkomma en längdskarv hos förpacknings- ämnet l utnyttjas induktionsvärmeteknik. För detta ändamål används en induktorbalk 2 och som mothàll en i fig 6 antydd dorn 3 av exempelvis vävbakelit.To achieve a longitudinal joint of the packaging blank 1, induction heating technology is used. For this purpose an inductor beam 2 is used and as a support a mandrel 3 of, for example, fabric bakelite indicated in Fig. 6.

Att försegla förhållandevis tjock, polymerbelagd alu- minium med induktionsvärme innebär speciella problem fram- för allt på grund av materialets låga resistans och goda värmeledningsförmäga. Med normala envarviga induktorer blir strömmen i induktor och tillhörande anpassningstransforma- tor oacceptabelt hög.Sealing relatively thick, polymer-coated aluminum with induction heat entails special problems, primarily due to the material's low resistance and good thermal conductivity. With normal single-speed inductors, the current in the inductor and associated matching transformer becomes unacceptably high.

Problemet kompliceras ytterligare vid längdskarvsför- segling, där den inducerade strömmen skall följa materia- lets kant så långt som möjligt och sedan snabbt svänga av.The problem is further complicated by longitudinal joint sealing, where the induced current must follow the edge of the material as far as possible and then quickly turn off.

Vid sättet enligt uppfinningen utnyttjas i stället en flervarvig induktor, företrädesvis en induktor med fem varv. I det visade fallet är ett varv vid stället där längdskarven skall åstadkommas utformad som en I-balk 4, W U 20 25 30 35 ; sus 571 medan de övriga varven utgörs av litztràd 5. En litztràd innehåller ett stort antal från varandra isolerade ledare, i föreliggande fall ca 400 ledare inom en total diameter av 2 mm, och ger därigenom en i tråden jämnt fördelad ström.In the method according to the invention, a multi-turn inductor is preferably used, preferably a five-turn inductor. In the case shown, a turn at the place where the longitudinal joint is to be made is formed as an I-beam 4, W U 20 25 30 35; sus 571 while the other turns consist of litz wire 5. A litz wire contains a large number of conductors insulated from each other, in the present case about 400 conductors within a total diameter of 2 mm, and thereby provides a current evenly distributed in the wire.

I-balksformen är vald för att det för förseglingen nödvändiga trycket på skarven skall kunna appliceras, och litztrådarna 5 är lagda i I-balkens liv för att koncentrera strömmen och åstadkomma den för snabb smältning och förseg- ling nödvändiga värmen. I-balken 4 med sina litztrådar 5 är infälld i ferritisk massa för att koncentrera strömmen. Vid försegling av 85 pm aluminium kan förseglingstider av 30- 300 ms åstadkommas.The I-beam shape is chosen so that the pressure necessary for the seal can be applied to the joint, and the litz wires 5 are laid in the life of the I-beam to concentrate the current and provide the heat necessary for rapid melting and sealing. The I-beam 4 with its litz wires 5 is recessed in ferritic mass to concentrate the current. When sealing 85 μm aluminum, sealing times of 30- 300 ms can be achieved.

Alla returledarna av litztràd 5 (till vänster i fig 4 och 5) är lagda intill varandra under en kopparplát 6 i in- duktorbalkens inneryta med syfte att fördela strömmen.All the return conductors of litz wire 5 (on the left in Figs. 4 and 5) are laid next to each other under a copper plate 6 in the inner surface of the inductor beam for the purpose of distributing the current.

Induktorbalken 2 kan vara försedd med skruvhål 2' för sin montering vid den ej visade maskinen för skarvningen.The inductor beam 2 can be provided with screw holes 2 'for its mounting at the machine (not shown) for splicing.

Vid överlappsskarvar, som det här är fråga om, ut- vecklas normalt värmen i det metallskikt som ligger närmast induktorn. Detta innebär att det kan uppstå en exempelvis ca 5 mm bred bränd zon på förpackningsmaterialets yta. Den- na måste då vara dekorfri på samma sätt som vid stålburkar och liknande med svetsad längdskarv.In the case of overlapping joints, as in this case, the heat normally develops in the metal layer closest to the inductor. This means that a burnt zone, for example about 5 mm wide, can occur on the surface of the packaging material. This must then be decor-free in the same way as with steel cans and the like with welded longitudinal joints.

Om parterna i längdskarven emellertid läggs på det sätt som framgår av fig 4 och 5, dvs om den part på vilken returlitztrådarna 5 och kopparplåten 6 anligger läggs un- derst i skarven, kommer såväl förseglingsströmmen som re- turströmmen att gå i den undre parten och sålunda värmen att koncentreras till det undre plåtskiktet. Härigenom sker uppvärmningen av det övre plåtskiktet underifrån, och det övre tryckta dekorskiktet skadas ej.However, if the parts of the longitudinal joint are laid in the manner shown in Figures 4 and 5, ie if the part on which the return lint wires 5 and the copper plate 6 abut is laid at the bottom of the joint, both the sealing current and the return current will go into the lower part thus the heat to be concentrated to the lower sheet metal layer. As a result, the upper sheet metal layer is heated from below, and the upper printed decorative layer is not damaged.

Där strömmen vänder vid längdskarvens ytterändar, blir strömtätheten så stor att materialet i förpacknings- âmnet skadas. Detta problem kan undvikas genom att en kop- parremsa 7 (fig 6) anordnas på dornen eller mothållet 3 på 10 15 505 571 förpackningsâmnets l baksida i anslutning till stället där strömmen vänder. En sådan remsa 7 är i sin längdriktning inskjuten några mm innanför längdskarvens ände. Den tar hand om den vändande strömmen och avlastar skarven. En sådan remsa 7 är normalt anordnad vid vardera änden av långdskarven. Det kan emellertid också förekomma att för- packningen förses med ett lock före längdskarvningen, var- vid det räcker med en remsa 7 vid skarvens fria ände.Where the current turns at the outer ends of the longitudinal joint, the current density becomes so great that the material in the packaging blank is damaged. This problem can be avoided by arranging a copper strip 7 (Fig. 6) on the mandrel or abutment 3 on the back of the packaging blank 1 in connection with the place where the current turns. Such a strip 7 is inserted in its longitudinal direction a few mm inside the end of the longitudinal joint. It takes care of the reversing current and relieves the joint. Such a strip 7 is normally arranged at each end of the longitudinal joint. However, it may also happen that the package is provided with a lid before the longitudinal splicing, whereby a strip 7 at the free end of the splice is sufficient.

Som en modifikation till den ovan angivna och på ritningarna visade utföringsformen med en I-balk kan man tänka sig andra profiler, såsom en U- eller T-balk, och antalet litztràdar kan exempelvis ligga i området 3-7.As a modification to the above-mentioned embodiment shown in the drawings with an I-beam, other profiles are conceivable, such as a U- or T-beam, and the number of litz threads can, for example, be in the range 3-7.

Ett annat sätt att åstadkomma den önskade effekten med strömkoncentration och tryckappliceringsförmága är att som induktor anordna ett antal, exempelvis fem, intill varandra stående, men från varandra isolerade koppar- stänger, vardera med en höjd av 4-5 mm och en tjocklek av 0,8 mm. I returledningsfasen kan dessa kopparstänger vara vridna 90° och ligga på något avstånd från varandra.Another way of achieving the desired effect with current concentration and pressure applicability is to arrange as an inductor a number, for example five, adjacent, but insulated copper rods, each with a height of 4-5 mm and a thickness of 0, 8 mm. In the return line phase, these copper rods can be rotated 90 ° and lie at some distance from each other.

Claims (3)

10 Ü 20 i 505 571 PATENTKRAV10 Ü 20 i 505 571 PATENTKRAV 1. Sätt vid längdskarvsförsegling med induktionsvärme av ett förpackningsämne (1) eller liknande av polymerbelagd metallplàt, varvid en induktor (4, 5) ansätts mot en skarv, bildad av en övre part och en undre part, k ä n n e- att induktorns (4, 5) returström leds t e c k n a t därav, via förpackningsämnets (1) undre part.In the case of longitudinal joint sealing with induction heat sealing of a packaging blank (1) or the like of polymer-coated sheet metal, an inductor (4, 5) being applied to a joint formed by an upper part and a lower part, it is known that the inductor ( 4, 5) return current is drawn thereof, via the lower part of the packaging blank (1). 2. Anordning vid längdskarvsförsegling med induk- tionsvärme av ett förpackningsämne (1) eller liknande av polymerbelagd metallplàt med en induktor (4, 5) för ansätt- ning mot en skarv, bildad av en övre part och en undre att induktorns (4, 5) returströmsledningar är anordnade i anslutning till för- part, k ä n n e t e c k n a d därav, packningsämnets (1) undre part.Device for longitudinal joint sealing with induction heat of a packaging blank (1) or similar of polymer-coated metal plate with an inductor (4, 5) for attachment to a joint, formed by an upper part and a lower part of the inductor (4, 5) ) return current lines are arranged in connection with the front part, characterized thereby, the lower part of the packing blank (1). 3. Anordning enligt krav 2, k ä n n e t e c k n a d därav, att induktorn utgörs av fyra litztrådar (4) anordna- de i livet hos en I-balk (5), och att returledarna av litztrád är lagda intill varandra pà avstånd från induktorlindningen i anslutning till som bildar en femte ledare, förpackningsämnets (1) undre part.Device according to claim 2, characterized in that the inductor consists of four litz wires (4) arranged in the life of an I-beam (5), and that the return conductors of litz wire are laid next to each other at a distance from the inductor winding in connection to form a fifth conductor, the lower part of the packaging blank (1).
SE9504566A 1995-12-20 1995-12-20 Methods and apparatus for longitudinal joint sealing with induction heat of a packaging material of polymer coated metal sheet SE505571C2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
SE9504566A SE505571C2 (en) 1995-12-20 1995-12-20 Methods and apparatus for longitudinal joint sealing with induction heat of a packaging material of polymer coated metal sheet
PCT/SE1996/001704 WO1997022524A1 (en) 1995-12-20 1996-12-19 A method and device at a longitudinal joint sealing of a package blank
AU12187/97A AU1218797A (en) 1995-12-20 1996-12-19 A method and device at a longitudinal joint sealing of a package blank

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9504566A SE505571C2 (en) 1995-12-20 1995-12-20 Methods and apparatus for longitudinal joint sealing with induction heat of a packaging material of polymer coated metal sheet

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SE9504566D0 SE9504566D0 (en) 1995-12-20
SE9504566L SE9504566L (en) 1997-06-21
SE505571C2 true SE505571C2 (en) 1997-09-15

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Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE518744A (en) * 1952-03-28
SE338424B (en) * 1969-06-23 1971-09-06 Spiess C F & Sohn
DE2653753C2 (en) * 1976-11-26 1986-04-17 Robert Bosch Gmbh, 7000 Stuttgart Device for producing a packaging tube from a packaging material web by welding the edge areas
SE410788B (en) * 1977-06-20 1979-11-05 Akerlund & Rausing Ab INDUCTION WELDING DEVICE
SE500572C2 (en) * 1990-10-11 1994-07-18 Tetra Laval Holdings & Finance Device for induction welding

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AU1218797A (en) 1997-07-14
WO1997022524A1 (en) 1997-06-26
SE9504566D0 (en) 1995-12-20
SE9504566L (en) 1997-06-21

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