US20040103620A1 - Speed independent sealing - Google Patents

Speed independent sealing Download PDF

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Publication number
US20040103620A1
US20040103620A1 US10/343,699 US34369903A US2004103620A1 US 20040103620 A1 US20040103620 A1 US 20040103620A1 US 34369903 A US34369903 A US 34369903A US 2004103620 A1 US2004103620 A1 US 2004103620A1
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United States
Prior art keywords
packages
inductor
package
sealing
row
Prior art date
Legal status (The legal status 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 status listed.)
Abandoned
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US10/343,699
Inventor
Gert Holmstrom
Karin Berg
Anders Wiberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tetra Laval Holdings and Finance SA
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Individual
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Assigned to TETRA LAVAL HOLDINGS & FINANCE S.A. reassignment TETRA LAVAL HOLDINGS & FINANCE S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BERG, KARIN, WIBERG, ANDERS, HOLMSTROM, GERT
Publication of US20040103620A1 publication Critical patent/US20040103620A1/en
Abandoned legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65BMACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
    • B65B51/00Devices for, or methods of, sealing or securing package folds or closures; Devices for gathering or twisting wrappers, or necks of bags
    • B65B51/10Applying or generating heat or pressure or combinations thereof
    • B65B51/22Applying or generating heat or pressure or combinations thereof by friction or ultrasonic or high-frequency electrical means, i.e. by friction or ultrasonic or induction welding
    • B65B51/227Applying or generating heat or pressure or combinations thereof by friction or ultrasonic or high-frequency electrical means, i.e. by friction or ultrasonic or induction welding by induction welding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining 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"
    • B29C65/36Joining 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
    • B29C65/3604Joining 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
    • B29C65/3644Joining 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining 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"
    • B29C65/36Joining 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
    • B29C65/3604Joining 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
    • B29C65/3656Joining 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining 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"
    • B29C65/36Joining 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
    • B29C65/3672Joining 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
    • B29C65/3676Joining 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
    • B29C65/368Joining 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/40General 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
    • B29C66/41Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43Joining a relatively small portion of the surface of said articles
    • B29C66/431Joining the articles to themselves
    • B29C66/4312Joining the articles to themselves for making flat seams in tubular or hollow articles, e.g. transversal seams
    • B29C66/43121Closing the ends of tubular or hollow single articles, e.g. closing the ends of bags
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/70General 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
    • B29C66/72General 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
    • B29C66/723General 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
    • B29C66/7232General 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
    • B29C66/72321General 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/80General aspects of machine operations or constructions and parts thereof
    • B29C66/83General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/836Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/91Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B29C66/91641Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux the heat or the thermal flux being non-constant over time
    • B29C66/91643Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux the heat or the thermal flux being non-constant over time following a heat-time profile
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/91Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B29C66/91651Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/91Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/919Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux characterised by specific temperature, heat or thermal flux values or ranges
    • B29C66/9192Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux characterised by specific temperature, heat or thermal flux values or ranges in explicit relation to another variable, e.g. temperature diagrams
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/93Measuring or controlling the joining process by measuring or controlling the speed
    • B29C66/934Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint 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
    • B29C66/112Single lapped joints
    • B29C66/1122Single lap to lap joints, i.e. overlap joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/80General aspects of machine operations or constructions and parts thereof
    • B29C66/83General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/834General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools moving with the parts to be joined
    • B29C66/8341Roller, cylinder or drum types; Band or belt types; Ball types
    • B29C66/83411Roller, cylinder or drum types
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/93Measuring or controlling the joining process by measuring or controlling the speed
    • B29C66/939Measuring or controlling the joining process by measuring or controlling the speed characterised by specific speed values or ranges
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/94Measuring or controlling the joining process by measuring or controlling the time
    • B29C66/949Measuring or controlling the joining process by measuring or controlling the time characterised by specific time values or ranges
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/90Measuring or controlling the joining process
    • B29C66/95Measuring or controlling the joining process by measuring or controlling specific variables not covered by groups B29C66/91 - B29C66/94
    • B29C66/959Measuring or controlling the joining process by measuring or controlling specific variables not covered by groups B29C66/91 - B29C66/94 characterised by specific values or ranges of said specific variables
    • B29C66/9592Measuring or controlling the joining process by measuring or controlling specific variables not covered by groups B29C66/91 - B29C66/94 characterised by specific values or ranges of said specific variables in explicit relation to another variable, e.g. X-Y diagrams
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00Other particular articles
    • B29L2031/712Containers; Packaging elements or accessories, Packages
    • B29L2031/7128Bags, sacks, sachets

Definitions

  • the present invention concerns a method and a device for sealing packages during continuous movement.
  • the method is normally to be used in a form and seal machine.
  • Packages are raised and sealed at one edge, normally the top in a first line of a form and seal machine. After the sealing the packages goes through one or more fillers. From the one or more fillers the packages are returned to a second line of the form and seal machine where the other edge of each package is sealed.
  • the two lines of the form and seal machine and the one or more fillers are commonly referred to as the filling machine.
  • a new form and seal machine has been developed to operate in a number (3-5) of fixed speeds. This machine is to fit in a packaging line for retortable food products. To improve the machine to work better together with existing filling technologies used in the business, demands have been raised to make the machine more flexible in terms of speed and, thus to be able to run in varying not pre-fixed speeds.
  • one object of the invention is to have a speed independent sealing.
  • a further object is to seal with the same equipment during different speeds and during acceleration and retardation.
  • packages are sealed during continuous movement.
  • a transportation means drives a row of packages through a sealing station comprising an inductor.
  • the inductor is driven in a pulse form.
  • a PLC system is used to control the pulses of the inductor.
  • the PLC system uses information from a motor drive and an encoder, respectively connected to the motor driving the transportation means.
  • FIG. 1 is a principal view of a sealing station in which the present invention may be used.
  • FIG. 2 is a diagram showing an example of the pulses of the inductor affecting each package.
  • FIG. 1 a row of packages 1 are indicated.
  • the row of packages 1 is feed at a constant speed in normal use. The speed may vary depending on the type of packages 1 and the goods to be filled in the packages 1 .
  • the packages 1 are arranged on some kind of transportation means (not shown) driven by a motor 8 .
  • the transportation means may be a chain having means for receiving each package 1 .
  • the motor 8 is controlled by a motor drive 9 .
  • an encoder 7 is connected to the motor 8 .
  • the encoder 7 and the motor drive 9 are connected to a PLC (programmable logic controller) system 6 .
  • the PLC system 6 is also connected to a generator 5 for induction heating (often referred to as IH generator 5 below).
  • the IH generator 5 is feeding an inductor 4 at a sealing station for the packages 1 .
  • the inductor 4 normally consists of two inductor plates, one on each side of the package 1 in the sealing station.
  • the encoder 7 normally comprises a disc rotating with the motor 8 .
  • an encoder 7 giving 256 pulses per rotation is used.
  • the 256 pulses are set to correspond to 2 packages and the space between them.
  • the position and speed of the packages 1 are given to the PLC system 6 by means of the encoder 7 and the motor drive 9 , respectively. This information is used by the PLC system to control the IH generator 5 and ultimately the inductor 4 .
  • the transportation means will be driven at different speeds.
  • the same filling machine may be driven in varying speeds.
  • a row of packages 1 pass an inductor 4 .
  • Each package 1 has a lower edge 2 and an upper edge 3 . Normally one of the edges are sealed first, then the package is filled and finally the other edge is sealed. The sealing is done by means of the inductor 4 heating up a metal, usually aluminium, in the edge area. When the aluminium is heated a plastic layer on each side of the edge area will be heated by the aluminium and melt. After the inductor 4 a number of pressure rolls (not shown) presses the edge together, whereby the heated plastic will melt together.
  • the edge of each package 1 has a length l p and the packages 1 of the row are separated by a space of a length l s .
  • the inductor 4 has a length of l i in the feeding direction of the packages 1 .
  • the sealing system of the present invention is intended for a continuously moving row of packages 1 .
  • the induction heating is applied in pulses given from the IH generator 5 to the inductor 4 .
  • the induction heating is applied in pulses with a fixed length.
  • the time between the pulses vary depending on the speed of the row of packages 1 .
  • the applied power is also slightly adjusted according to the speed, i.e. the power is somewhat lower at higher speeds. This is done to compensate for the difference in cooling time between application of induction heating and the pressure rolls.
  • the pulses are started by the PLC system 6 .
  • the position of the packages 1 is supervised by the encoder 7 connected to the PLC system 6 .
  • FIG. 2 the sealing of one package is shown in a diagrammatic form.
  • the package 1 At the first pulse (the uppermost curve) the package 1 has just come into the area of the inductor 4 and, thus, only the right part of the lower edge 2 (as shown in FIG. 1) will be affected by the inductor 4 .
  • the package 1 In the pause between the first and second pulses the package 1 has moved further to the right and as shown by the second curve a larger part of the lower edge 2 will be affected by the inductor 4 in the sealing station.
  • the package 1 For the third and fourth pulses the package 1 has moved even further to the right for each pulse. It should be noted that in the position where the energy of the first pulse starts to increase the energy of the third pulse starts to decrease. The same is true for the second and fourth pulses.
  • each package 1 is affected by a number of partial pulses (pulses 1 to 4 of FIG. 2), the sum of which corresponds to two pulses over the entire length of the package 1 .
  • the speed of the filling machine is set to 24 000 packages per hour, i.e. 24 000 packages are sealed in one hour.
  • the pulse time is set to 64 ms and the pause between the pulses will become 11 ms.
  • the number of pulses per inductor length l i may be varied.
  • the number of pulses per inductor length l i is preferably 2, 4, 8, 16 etc, i.e. equally divisible with 256.
  • the slope at the start or end of each curve depends on the speed and thus the distance travelled by the package during the duration of the pulse.
  • the PLC system 6 will control the pulses to the inductor 4 based on this information.
  • the pulse length is set in relation to the highest possible speed in such a way that the pulses do not interfere.
  • the frequency of the pulses are related to the speed of the packages 1 the sealing will work both during acceleration and retardation and if the speed is fluctuating. The sealing effect during acceleration and retardation is improved if the number of pulses per package is increased. In the example of FIG. 2 only two pulses are shown for the sake of simplicity. Normally, 4 to 16 pulses per package will be used.

Abstract

The present invention concerns a method and a device for sealing packages (1) during continuous movement. A row of packages (1) is driven by means of a motor (8) through a sealing station comprising an inductor (4). The inductor (4) is driven in a pulse form by means of an IH (induction heating) inductor (5). A PLC system (6) is used to control the IH generator (5). The PLC system (6) receives information regarding speed and position of the packages (1) by means of a motor drive (9) and an encoder (7), respectively.

Description

    TECHNICAL FIELD
  • The present invention concerns a method and a device for sealing packages during continuous movement. The method is normally to be used in a form and seal machine. [0001]
  • STATE OF THE ART
  • Packages are raised and sealed at one edge, normally the top in a first line of a form and seal machine. After the sealing the packages goes through one or more fillers. From the one or more fillers the packages are returned to a second line of the form and seal machine where the other edge of each package is sealed. In this description the two lines of the form and seal machine and the one or more fillers are commonly referred to as the filling machine. [0002]
  • Previously separate induction heating transformers were used for different speeds of the machine. Thus, application of induction heating was done with a continuous power for each speed during the package movement. It was necessary to have different combinations of transformers and capacitors to get the correct phase-shift of the signal for the different speeds. When the speed of the machine was changed, e.g. due to another type or sizes of packages, the transformers were to be changed. The earlier methods resulted in wasting of a large number of packages during acceleration and retardation. [0003]
  • SUMMARY OF THE INVENTION
  • There is a need for a speed independent sealing of packages. The sealing should be made during continuous movement of the packages. [0004]
  • As an example, a new form and seal machine has been developed to operate in a number (3-5) of fixed speeds. This machine is to fit in a packaging line for retortable food products. To improve the machine to work better together with existing filling technologies used in the business, demands have been raised to make the machine more flexible in terms of speed and, thus to be able to run in varying not pre-fixed speeds. [0005]
  • Thus, one object of the invention is to have a speed independent sealing. [0006]
  • A further object is to seal with the same equipment during different speeds and during acceleration and retardation. [0007]
  • In the method of the present invention packages are sealed during continuous movement. A transportation means drives a row of packages through a sealing station comprising an inductor. The inductor is driven in a pulse form. A PLC system is used to control the pulses of the inductor. The PLC system uses information from a motor drive and an encoder, respectively connected to the motor driving the transportation means. [0008]
  • As stated above the top of each package is normally first sealed and thus the package is feed upside down. The package is then filled with the goods, whereafter the bottom of the package is sealed. The sealing of both the top and the bottom takes place in the form and seal machine. Thus, for each form and seal machine there will be two sealing stations, both normally controlled by the PLC system.[0009]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • The invention will be described further below with reference to the enclosed drawings. [0010]
  • FIG. 1 is a principal view of a sealing station in which the present invention may be used. [0011]
  • FIG. 2 is a diagram showing an example of the pulses of the inductor affecting each package. [0012]
  • DETAILED DESCRIPTION OF THE INVENTION
  • In FIG. 1 a row of [0013] packages 1 are indicated. The row of packages 1 is feed at a constant speed in normal use. The speed may vary depending on the type of packages 1 and the goods to be filled in the packages 1. The packages 1 are arranged on some kind of transportation means (not shown) driven by a motor 8. The transportation means may be a chain having means for receiving each package 1. The motor 8 is controlled by a motor drive 9. Furthermore, an encoder 7 is connected to the motor 8. The encoder 7 and the motor drive 9 are connected to a PLC (programmable logic controller) system 6. The PLC system 6 is also connected to a generator 5 for induction heating (often referred to as IH generator 5 below). The IH generator 5 is feeding an inductor 4 at a sealing station for the packages 1. The inductor 4 normally consists of two inductor plates, one on each side of the package 1 in the sealing station.
  • In practice the [0014] encoder 7 normally comprises a disc rotating with the motor 8. In one embodiment an encoder 7 giving 256 pulses per rotation is used. The 256 pulses are set to correspond to 2 packages and the space between them. The position and speed of the packages 1 are given to the PLC system 6 by means of the encoder 7 and the motor drive 9, respectively. This information is used by the PLC system to control the IH generator 5 and ultimately the inductor 4.
  • Depending on e.g. the capacity of the filler or fillers, the size of the [0015] packages 1 and the form of the goods to be filled in the packages 1 the transportation means will be driven at different speeds. Thus the same filling machine may be driven in varying speeds.
  • In FIG. 1 a row of [0016] packages 1 pass an inductor 4. Each package 1 has a lower edge 2 and an upper edge 3. Normally one of the edges are sealed first, then the package is filled and finally the other edge is sealed. The sealing is done by means of the inductor 4 heating up a metal, usually aluminium, in the edge area. When the aluminium is heated a plastic layer on each side of the edge area will be heated by the aluminium and melt. After the inductor 4 a number of pressure rolls (not shown) presses the edge together, whereby the heated plastic will melt together. The edge of each package 1 has a length lp and the packages 1 of the row are separated by a space of a length ls. The inductor 4 has a length of li in the feeding direction of the packages 1. The length li of the inductor 4 is the sum of the length lp of one package 1 and the distance ls between two adjacent packages 1, i.e li=lp+ls.
  • The sealing system of the present invention is intended for a continuously moving row of [0017] packages 1. The induction heating is applied in pulses given from the IH generator 5 to the inductor 4. The induction heating is applied in pulses with a fixed length. The time between the pulses vary depending on the speed of the row of packages 1. The applied power is also slightly adjusted according to the speed, i.e. the power is somewhat lower at higher speeds. This is done to compensate for the difference in cooling time between application of induction heating and the pressure rolls. The pulses are started by the PLC system 6. The position of the packages 1 is supervised by the encoder 7 connected to the PLC system 6.
  • In FIG. 2 the sealing of one package is shown in a diagrammatic form. At the first pulse (the uppermost curve) the [0018] package 1 has just come into the area of the inductor 4 and, thus, only the right part of the lower edge 2 (as shown in FIG. 1) will be affected by the inductor 4. In the pause between the first and second pulses the package 1 has moved further to the right and as shown by the second curve a larger part of the lower edge 2 will be affected by the inductor 4 in the sealing station. For the third and fourth pulses the package 1 has moved even further to the right for each pulse. It should be noted that in the position where the energy of the first pulse starts to increase the energy of the third pulse starts to decrease. The same is true for the second and fourth pulses. When the package 1 leaves the area of the inductor 4 the lower edge 2 will have been given a constant induction heating over its entire length lp. This is reflected in the lowermost curve of FIG. 2 showing the total energy given by the four pulses shown in the four upper curves of FIG. 2. In this case the energy is applied to the package 1 by means of two pulses per inductor length li, i.e. each package 1 is affected by a number of partial pulses (pulses 1 to 4 of FIG. 2), the sum of which corresponds to two pulses over the entire length of the package 1. In the example of FIG. 2 the speed of the filling machine is set to 24 000 packages per hour, i.e. 24 000 packages are sealed in one hour. The pulse time is set to 64 ms and the pause between the pulses will become 11 ms.
  • A person skilled in the art realises that the number of pulses per inductor length l[0019] i may be varied. For an encoder with 256 pulses per revolution the number of pulses per inductor length li is preferably 2, 4, 8, 16 etc, i.e. equally divisible with 256. The slope at the start or end of each curve depends on the speed and thus the distance travelled by the package during the duration of the pulse.
  • At start up the position of the [0020] first package 1 coming into the area of the inductor 4 is used to trigger the sealing system. As the starting point and the speed of the packages 1 are known the PLC system 6 will control the pulses to the inductor 4 based on this information. The pulse length is set in relation to the highest possible speed in such a way that the pulses do not interfere. As the frequency of the pulses are related to the speed of the packages 1 the sealing will work both during acceleration and retardation and if the speed is fluctuating. The sealing effect during acceleration and retardation is improved if the number of pulses per package is increased. In the example of FIG. 2 only two pulses are shown for the sake of simplicity. Normally, 4 to 16 pulses per package will be used.

Claims (11)

1. A method of sealing packages (1) during continuous movement, in which a row of packages (1) is driven by means of a motor (8) through a sealing station comprising an inductor (4), characterized in that the inductor (4) is driven in a pulse form, that the pulses are of a fixed length and that the time between the pulses vary depending on the speed of the row of packages (1).
2. The method of claim 1, characterized in that a PLC system (6) is used to control the feeding of the inductor (4) by means of a IH (induction heating) generator (5).
3. The method of claim 2, characterized in that information regarding speed and position of the packages (1) is given to the PLC system (6).
4. The method of claim 3, characterized in that the information regarding speed and position of the packages (1) is given by means of a motor drive (9) and an encoder (7).
5. The method of any of the previous claims, characterized in that the applied power is adjusted depending on the speed.
6. The method of any of the previous claims, characterized in that each package (1) of the row of packages (1) has the same length (lp) in the feeding direction and that the packages (1) are separated by a distance (ls) from each other.
7. The method of claim 7, characterized in that the length (li) of the inductor (4) in the feeding direction of the packages (1) is the same as the length (lp) of one package plus the length (ls) of the space between two adjacent packages (1).
8. The method of any of the previous claims, characterized in that each package is given a constant sealing energy throughout the length (lp) of the package (1).
9. The method of any of the previous claims, characterized in that the first package (1) of the row of packages (1) triggers the sealing system at start-up.
10. A device for continuous sealing of packages (1) in a sealing station comprising an inductor (4), whereby a row of packages (1) is driven by means of a motor (9) through the sealing station passing the inductor (4), consisting of two plates on each side of the row of packages (1), characterized in that an IH (induction heating) generator (5) is connected to the inductor (4) and that the IH generator (5) is controlled by a PLC system (6) connected to the IH generator (5).
11. The device of claim 10, characterized in that the PLC system (6) is connected to receive information from a motor drive (9) and an encoder (7), respectively, connected to the motor (8).
US10/343,699 2000-10-13 2001-10-05 Speed independent sealing Abandoned US20040103620A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE0003712A SE518877C2 (en) 2000-10-13 2000-10-13 Procedure for sealing packages under continuous movement
SE0003712-7 2000-10-13
PCT/SE2001/002182 WO2002030754A1 (en) 2000-10-13 2001-10-05 Speed independent sealing

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US20040103620A1 true US20040103620A1 (en) 2004-06-03

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US10/343,699 Abandoned US20040103620A1 (en) 2000-10-13 2001-10-05 Speed independent sealing

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US (1) US20040103620A1 (en)
EP (1) EP1334029B1 (en)
JP (1) JP3759728B2 (en)
CN (1) CN100450875C (en)
AU (1) AU2001294466A1 (en)
BR (1) BR0114003B1 (en)
DE (1) DE60130574T2 (en)
ES (1) ES2290174T3 (en)
MX (1) MXPA03003166A (en)
RU (1) RU2272760C2 (en)
SE (1) SE518877C2 (en)
WO (1) WO2002030754A1 (en)

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US20070067458A1 (en) * 2005-09-20 2007-03-22 Rockwell Software, Inc. Proxy server for integration of industrial automation data over multiple networks

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US5025123A (en) * 1988-10-07 1991-06-18 Continental Can Company, Inc. Apparatus and method for sealing a lid onto a container
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US6561962B1 (en) * 2000-03-10 2003-05-13 Converting Systems, Inc. Line plastic bag machine

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US5025123A (en) * 1988-10-07 1991-06-18 Continental Can Company, Inc. Apparatus and method for sealing a lid onto a container
US5000725A (en) * 1988-11-07 1991-03-19 Fmc Corporation Bi-directional registration of servo indexed webs
US5138815A (en) * 1991-11-12 1992-08-18 Doboy Packaging Machinery, Inc. Microprocessor controlled SCR motor drives for wrapping machine
US5566526A (en) * 1995-08-25 1996-10-22 Ibaraki Seiki Machinery Company, Ltd. Device motor controlling apparatus for use in packaging machine
US6561962B1 (en) * 2000-03-10 2003-05-13 Converting Systems, Inc. Line plastic bag machine

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BR0114003B1 (en) 2010-03-09
CN1469828A (en) 2004-01-21
AU2001294466A1 (en) 2002-04-22
EP1334029A1 (en) 2003-08-13
EP1334029B1 (en) 2007-09-19
JP3759728B2 (en) 2006-03-29
SE0003712D0 (en) 2000-10-13
MXPA03003166A (en) 2004-02-12
ES2290174T3 (en) 2008-02-16
SE0003712L (en) 2002-04-14
SE518877C2 (en) 2002-12-03
DE60130574D1 (en) 2007-10-31
CN100450875C (en) 2009-01-14
RU2272760C2 (en) 2006-03-27
WO2002030754A1 (en) 2002-04-18
DE60130574T2 (en) 2007-12-27
BR0114003A (en) 2003-08-19
JP2004510653A (en) 2004-04-08

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