CH397227A - Sealing device for welding heat-sealable packaging materials - Google Patents
Sealing device for welding heat-sealable packaging materialsInfo
- Publication number
- CH397227A CH397227A CH973561A CH973561A CH397227A CH 397227 A CH397227 A CH 397227A CH 973561 A CH973561 A CH 973561A CH 973561 A CH973561 A CH 973561A CH 397227 A CH397227 A CH 397227A
- Authority
- CH
- Switzerland
- Prior art keywords
- sealing
- jaws
- clamping jaws
- jaw
- clamping
- Prior art date
Links
Classifications
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- 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
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
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- 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
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
- B29C65/24—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools characterised by the means for heating the tool
- B29C65/30—Electrical means
- B29C65/305—Electrical means involving the use of cartridge heaters
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- 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
- B29C66/004—Preventing sticking together, e.g. of some areas of the parts to be joined
- B29C66/0042—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined
- B29C66/0044—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined using a separating sheet, e.g. fixed on the joining tool
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- 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
- B29C66/03—After-treatments in the joint area
- B29C66/034—Thermal after-treatments
- B29C66/0342—Cooling, e.g. transporting through welding and cooling zone
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- 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
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- 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
- B29C66/431—Joining the articles to themselves
- B29C66/4312—Joining the articles to themselves for making flat seams in tubular or hollow articles, e.g. transversal seams
- B29C66/43121—Closing the ends of tubular or hollow single articles, e.g. closing the ends of bags
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- 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
- B29C66/73—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/739—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/7392—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
- B29C66/73921—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
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- 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
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
- B29C66/8122—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
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- 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
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
- B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
- B29C66/81427—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined comprising a single ridge, e.g. for making a weakening line; comprising a single tooth
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- 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
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/816—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the mounting of the pressing elements, e.g. of the welding jaws or clamps
- B29C66/8167—Quick change joining tools or surfaces
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- 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
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/818—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
- B29C66/8181—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the cooling constructional aspects
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- 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
- B29C66/82—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps
- B29C66/822—Transmission mechanisms
- B29C66/8221—Scissor or lever mechanisms, i.e. involving a pivot point
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- 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
- B29C66/82—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps
- B29C66/822—Transmission mechanisms
- B29C66/8227—Transmission mechanisms using springs
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- 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
- B29C66/8324—Joining or pressing tools pivoting around one axis
- B29C66/83241—Joining or pressing tools pivoting around one axis cooperating pivoting tools
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- 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
- B29C66/84—Specific machine types or machines suitable for specific applications
- B29C66/849—Packaging machines
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B51/00—Devices for, or methods of, sealing or securing package folds or closures; Devices for gathering or twisting wrappers, or necks of bags
- B65B51/10—Applying or generating heat or pressure or combinations thereof
- B65B51/14—Applying or generating heat or pressure or combinations thereof by reciprocating or oscillating members
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- 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
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/16—Cooling
- B29C2035/1658—Cooling using gas
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- 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
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- 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
- B29L2031/7128—Bags, sacks, sachets
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
- Package Closures (AREA)
Description
Siegelvorrichtung zum Verschweissen heisssiegelfähiger Packstoffe
Die Erfindung bezieht sich auf eine Siegelvorrichtung mit mindestens einer Siegelbacke zum Verschweissen von heisssiegelfähigen Packstoffen.
Zum Verschweissen von heisssiegelfähigen Packstoffen werden in den meisten Fällen dauerbeheizte, zangenartig gegeneinander bewegbare Siegelbacken aus Metall verwendet. Diese eignen sich gut zum Siegeln von Packstoffen, welche aus einer Träger schicht und ! einer heisssiegelfähigen Beschichtung be- stehen. Bei thermoplastischen Folien aus Polyäthylen oder ähnlichen polymeren Kunststoffen hat es sich jedoch gezeigt, dass dann, wenn die Siegelbacken nach dem Erwärmen der Nahtstelle der Folien auf Sclimelztemperatur von der Naht abgezogen werden, sehr oft Teile des Materials an den Siegeiflächen der Backen kleben bleiben.
Um dies zu vermeiden, wurde schon vorgeschlagen, an den Siegelbacken Überzüge oder Bänder aus antiadhäsiven Werkstoffen, z. B. Tetrafluoräthylen, anzubringen, da dieser Stoff sich von den erwärmten Folien besonders gut ablöst. Die Festigkeit und Dichtheit der mittels dieser Vorrichtung hergestellten Nähte lassen jedoch noch zu wünschen übrig. Dies rührt daher, dass der durch die Siegelbacken auf die Naht ausgeübte Druck in dem Augenblick unterbrochen wird, wenn die Folien in der Nahtstelle sich im Schmelzzustand befinden und im Begriff sind, miteinander zu verschmelzen. Durch das Aufheben des Pressdrucks können sich die Folien der Nahtstelle infolge der Wärmedehnung des Materials teilweise voneinander abheben, so dass Blasen und undichte Stellen innerhalb der Naht entstehen.
Um die Siegelnähte bis zu ihrer Verfestigung unter Druck zu halten, sind auch schon Vorrichtungen entwickelt worden, bei denen an den Siegelbacken Heizbänder befestigt sind, welche kurzzeitig mittels eines starken elektrischen Stromimpulses ersitzt werden. Dabei werden die Folien in den Schmelzzustand verbracht und verbinden und verfestigen sich noch, während sie unter dem Pressdruck der sich wieder abkühlenden Siegelbacken stehen.
Mittels dieser Vorrichtung hergestellte Siegelnähte weisen in ihren Randzonen jedoch feine Risse auf, welche die Dichtigkeit der fertigen Packungen herabsetzen. Dieser Nachteil rührt daher, dass beim Aufheizen des Heizbandes eine Temperatur entsteht, die infolge der kurzen Siegelzeit weit über der Schmelztemperatur der Folien liegen muss, um den nötigen Wärmeübergang zu erreichen. Die dabei auftretenden Temperaturdifferenzen in den Randzonen der Naht führen dann, ähnlich wie bei Metallen, zu Spannungen und Rissen.
Um die oben genannten Nachteile zu beheben, wird gemäss der Erfindung für eine Siegeivorrichtung mit mindestens einer Siegelbacke zum Verschweissen heisssiegelfähiger Packstoffe vorgeschlagen, dass mindestens einer dauerbeheizten, mit einer Abdeckung aus einem antiadhäsiven Werkstoff versehenen Sie geibacke eine für sich bewegliche Klemmbacke zugeordnet und für die Backen eine Steuervorrichtung vorgesehen ist, die bei Beendigung des Siegelvorgangs zunächst die Siegelbacken und dann mit einer gewissen Verzögerung die Klemmbacken von der Naht abhebt. Als antiadhäsiver Werkstoff kann, wie bekannt, Tetrafluoräthylen zur Anwendung kommen.
Besonders vorteilhaft ist es, wenn die genannte bewegliche Klemmbacke beiderseits der Siegelbäcke wirksam ist.
Bei einer besonders zweckmässigen Ausführungsform der Vorrichtung und mindestens zwei beweglichen Siegelbacken können die jeweils an einer Sie gelb lacke angeordneten, zangenartig ausgebildeten Klemmbacken als Träger je eines Bandes aus antiadhäsivem Werkstoff dienen und mit einem von letzterem überdeckten Längs schlitz versehen sein, durch den je eine Klemmbacke der ebenfalls zangenartig ausgebildeten Siegelbacken hindurchführbar ist.
Zur Beschleunigung der Abkühlung der Siegelnaht kann dabei an jeder Klemmbacke mindestens eine automatisch durch die Relativbewegung der Siegelbacken gegen die Klemmbacken gesteuerte Düse angeordnet werden, die nach dem Abheben der Siegelbacken Kühlluft gegen die Naht bläst.
Der Vorteil der erfindungsgemässen Vorrichtung liegt vor allem darin, dass einenseits die Beheizung der Siegelbacken mittels eines elektrischen Dauerheizkörpers, d. h. in besonders einfacher Weise durchgeführt werden kann und dass anderseits die Vorteile der Impulsheizung erzielt werden, ohne dass man deren eingangs genannte Nachteile in Kauf nehmen muss.
Die Erfindung wird nachstehend anhand eines bevorzugten Ausführungsbeispiels und schematischer Zeichnungen erläutert.
Es zeigen:
Fig. 1 die Vorrichtung des Ausführungsbeispiels in Seitenansicht teilweise im Schnitt,
Fig. 2 die Vorrichtung gemäss Fig. 1 im Schnitt in der Ebene II-II der Fig. 1.
Die dargestellte Vorrichtung ist zum Verschliessen von Beuteln eingerichtet, deren Beutelmund Innenseite gegen Innenseite mittels Siegelbacken 1, 2 verschweisst wird. Die Siegelbacken 1, 2 werden mittels je einer eingebauten elektrischen Heizpatrone 3, 4 auf eine bestimmte Temperatur erwärmt, die sich nach dem zu verschweissenden Material richtet.
Um den Beutelmund zwischen die Siegelbacken 1, 2 einführen zu können, sind diese an zangenartig verschwenkbaren Armen 5, 6 befestigt. Um denselben Drehpunkt verschwenkbar sind an Armen 7, 8 befestigte Klemmbacken 9, 10 angeordnet, welche den Beutelmund unmittelbar oberhalb und unterhalb der Siegelnaht festklemmen. Diese Klemmbacken 9, 10 weisen dazu je einen Schlitz auf, durch den die Siegelbacken 1, 2 hindurchtreten können. Auf der einander zugewandten Seite der Klemmbacken 9, 10 sind mittels Schrauben 12 und Leister 13 Bänder 14 aus mit Tetrafluoräthylen beschichtetem Glasfasergewebe angebracht, welche die Siegelflächen der Siegelbacken 1, 2 gegen das zu verschweissende Material abdecken, um eine Verklebung zu vermeiden.
Die Bänder 14 sind mittels Federn 25 und Leisten 26 unter Spannung gehalten. Die Klemmbacken 9, 10 und ! Siegelbacken 1, 2 werden gemeinsam gesteuert.
Beim Gegeneinanderführen dieser Backen kommen jedoch die Klemmbacken 9, 10 zuerst mit dem zu verschweissenden Material zur Anlage. Dies wird durch Federn 15, 16 bewirkt, welche zwischen den Armen 5 und 7 bzw. 6 und 8 angeordnet sind.
Damit nach dem Verschweissen des Beutelmundes die Nahtstelle bis zu ihrer Verfestigung unter Spannung gehalten wird, werden zunächst die Siegelbacken 1, 2 ein bestimmtes Stück zurückgezogen, wobei die Klemmbacken 9, 10 unter der Wirkung der Federn 15, 16 an den Nahtwurzeln angreifen zusammen mit den Bändern 14 die Naht unter Spannung halten. Hat sich die Naht verfestigt, so werden die Arme 5, 6 weiter auseinandergespreizt, wobei die die Klemmbacken 9, 10 tragenden Arme 7, 8 ebenfalls gespreizt werden. Zu diesem Zweck sind an den Armen 5, 6, ein Langloch 17 aufweisende Laschen 18 befestigt, in deren Langloch 17 an den Armen 7, 8 befestigte Stifte 19 eingreifen.
Um das Abkühlen und Verfestigen der Naht nach dem Verschweissen zu beschleunigen, sind in den Klemmbacken 9, 10 Bohrungen 20 und eine Anzahl Düsen 21 vorgesehen, durch welche durch eine Leitung 22 zugeführte Kühlluft auf die Nahtstelle geblasen wird. Zur Steuerung der Kühlluft ist vor den Austrittsöffnungen der Düsen 21 in jeder Klemmbacke 9, 10 eine verschwenkbare Klappe 23 vorgesehen, welche im Wege der Siegelbacken 1, 2 liegt und von letzteren derart betätigt wird, dass während des Siegelns die Austrittsöffnungen der Düsen 21 abgedeckt und danach zum Abkühlen der Naht freigegeben werden.
Abschliessend ist noch zu bemerken, dass anstelle der weiter oben angegebenen Bänder aus Tetrafluor äthylen auch solche aus Glasfaserstoff, der mit Sili konkautschuk imprägniert ist, Verwendung finden können.
Sealing device for welding heat-sealable packaging materials
The invention relates to a sealing device with at least one sealing jaw for welding heat-sealable packaging materials.
For the welding of heat-sealable packaging materials, permanently heated sealing jaws made of metal, which can be moved against one another like tongs, are used in most cases. These are well suited for sealing packaging materials that consist of a carrier layer and! a heat-sealable coating exist. In the case of thermoplastic films made of polyethylene or similar polymeric plastics, however, it has been shown that when the sealing jaws are pulled off the seam after the seam of the films has been heated to melting temperature, parts of the material very often stick to the sealing surfaces of the jaws.
In order to avoid this, it has already been proposed that coatings or tapes made of anti-adhesive materials, e.g. B. Tetrafluoroethylene to attach, as this substance is particularly easy to detach from the heated films. However, the strength and tightness of the seams produced by means of this device still leave something to be desired. This is due to the fact that the pressure exerted on the seam by the sealing jaws is interrupted at the moment when the foils in the seam are in the melt state and are about to fuse together. By releasing the pressure, the foils of the seam can partially lift from one another due to the thermal expansion of the material, so that bubbles and leaks occur within the seam.
In order to keep the sealing seams under pressure until they solidify, devices have already been developed in which heating bands are attached to the sealing jaws, which are briefly attached by means of a strong electrical current pulse. The foils are brought into the melting state and are still connected and solidified while they are under the pressure of the sealing jaws, which are cooling down again.
However, sealing seams produced by means of this device have fine cracks in their edge zones, which reduce the tightness of the finished packs. This disadvantage arises from the fact that when the heating tape is heated up, a temperature arises which, due to the short sealing time, has to be well above the melting temperature of the foils in order to achieve the necessary heat transfer. The temperature differences that occur in the edge zones of the seam then lead to tensions and cracks, similar to metals.
In order to remedy the above-mentioned disadvantages, it is proposed according to the invention for a sealing device with at least one sealing jaw for welding heat-sealable packaging materials that at least one permanently heated geiback provided with a cover made of an anti-adhesive material is assigned a movable jaw and for the jaws a control device is provided which, when the sealing process is completed, first lifts the sealing jaws and then, with a certain delay, the clamping jaws from the seam. As is known, tetrafluoroethylene can be used as an anti-adhesive material.
It is particularly advantageous if the said movable clamping jaw is effective on both sides of the sealing jaws.
In a particularly expedient embodiment of the device and at least two movable sealing jaws, the tong-like clamping jaws arranged on a yellow lacquer can each serve as a carrier for a tape made of anti-adhesive material and can be provided with a longitudinal slot covered by the latter, through each of which a clamping jaw the sealing jaws, which are also designed like pliers, can be passed through.
To accelerate the cooling of the sealing seam, at least one nozzle which is automatically controlled by the relative movement of the sealing jaws against the clamping jaws can be arranged on each clamping jaw, which nozzle blows cooling air against the seam after the sealing jaws are lifted off.
The advantage of the device according to the invention lies primarily in the fact that, on the one hand, the sealing jaws are heated by means of an electrical permanent heating element, i.e. H. can be carried out in a particularly simple manner and that, on the other hand, the advantages of pulse heating can be achieved without having to accept the disadvantages mentioned at the beginning.
The invention is explained below with reference to a preferred exemplary embodiment and schematic drawings.
Show it:
1 shows the device of the embodiment in a side view, partially in section,
FIG. 2 shows the device according to FIG. 1 in section in the plane II-II of FIG.
The device shown is designed to close bags, the mouth of which is welded from the inside to the inside by means of sealing jaws 1, 2. The sealing jaws 1, 2 are each heated to a certain temperature by means of a built-in electrical heating cartridge 3, 4, which depends on the material to be welded.
In order to be able to introduce the mouth of the bag between the sealing jaws 1, 2, these are attached to arms 5, 6 which can be pivoted like pliers. Clamping jaws 9, 10 attached to arms 7, 8 are arranged pivotable about the same fulcrum and clamp the mouth of the bag directly above and below the sealing seam. For this purpose, these clamping jaws 9, 10 each have a slot through which the sealing jaws 1, 2 can pass. On the facing side of the clamping jaws 9, 10, by means of screws 12 and Leister 13, tapes 14 made of glass fiber fabric coated with tetrafluoroethylene are attached, which cover the sealing surfaces of the sealing jaws 1, 2 against the material to be welded in order to avoid sticking.
The bands 14 are kept under tension by means of springs 25 and strips 26. The clamping jaws 9, 10 and! Sealing jaws 1, 2 are controlled together.
When these jaws are brought against one another, however, the clamping jaws 9, 10 first come into contact with the material to be welded. This is effected by springs 15, 16 which are arranged between the arms 5 and 7 or 6 and 8.
So that after welding the mouth of the bag, the seam is kept under tension until it solidifies, the sealing jaws 1, 2 are first retracted a certain amount, with the clamping jaws 9, 10 attacking the seam roots under the action of the springs 15, 16 together with the Straps 14 keep the seam under tension. If the seam has solidified, the arms 5, 6 are spread further apart, the arms 7, 8 carrying the clamping jaws 9, 10 also being spread. For this purpose, tabs 18 having an elongated hole 17 are attached to the arms 5, 6, and pins 19 attached to the arms 7, 8 engage in the elongated hole 17 thereof.
In order to accelerate the cooling and solidification of the seam after welding, bores 20 and a number of nozzles 21 are provided in the clamping jaws 9, 10 through which cooling air supplied through a line 22 is blown onto the seam. To control the cooling air, a pivotable flap 23 is provided in front of the outlet openings of the nozzles 21 in each clamping jaw 9, 10, which lies in the way of the sealing jaws 1, 2 and is operated by the latter in such a way that the outlet openings of the nozzles 21 are covered and during sealing then released to cool the seam.
Finally, it should be noted that instead of the tetrafluoroethylene tapes given above, tapes made of fiberglass impregnated with silicone rubber can also be used.
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEH0040371 | 1960-09-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
CH397227A true CH397227A (en) | 1965-08-15 |
Family
ID=7154230
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH973561A CH397227A (en) | 1960-09-07 | 1961-08-21 | Sealing device for welding heat-sealable packaging materials |
Country Status (2)
Country | Link |
---|---|
CH (1) | CH397227A (en) |
GB (1) | GB916841A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112644800A (en) * | 2020-12-24 | 2021-04-13 | 常州琉璃光生物科技有限公司 | A packaging mechanism for production of freeze-drying facial mask |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3992981A (en) * | 1975-11-19 | 1976-11-23 | Fmc Corporation | Web stripping apparatus |
-
1961
- 1961-08-21 CH CH973561A patent/CH397227A/en unknown
- 1961-09-04 GB GB3165861A patent/GB916841A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112644800A (en) * | 2020-12-24 | 2021-04-13 | 常州琉璃光生物科技有限公司 | A packaging mechanism for production of freeze-drying facial mask |
Also Published As
Publication number | Publication date |
---|---|
GB916841A (en) | 1963-01-30 |
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