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EP1015230A1 - Packaging machine - Google Patents

Packaging machine

Info

Publication number
EP1015230A1
EP1015230A1 EP98909581A EP98909581A EP1015230A1 EP 1015230 A1 EP1015230 A1 EP 1015230A1 EP 98909581 A EP98909581 A EP 98909581A EP 98909581 A EP98909581 A EP 98909581A EP 1015230 A1 EP1015230 A1 EP 1015230A1
Authority
EP
European Patent Office
Prior art keywords
web
hot air
speed
edges
machine according
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.)
Withdrawn
Application number
EP98909581A
Other languages
German (de)
French (fr)
Inventor
Kevin Richard Fincham
Jamie Thums
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.)
Mpac Group PLC
Original Assignee
Molins Ltd
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 Molins Ltd filed Critical Molins Ltd
Publication of EP1015230A1 publication Critical patent/EP1015230A1/en
Withdrawn legal-status Critical Current

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
    • 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
    • B29C65/10—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using hot gases (e.g. combustion gases) or flames coming in contact with at least one 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
    • B29C66/01—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
    • 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
    • B29C66/431—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
    • 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
    • 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
    • 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
    • B29C66/836—Moving 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
    • 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
    • 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
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring 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
    • B29C66/9141—Measuring 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 temperature
    • 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
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring 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
    • B29C66/9141—Measuring 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 temperature
    • B29C66/91431—Measuring 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 temperature the temperature being kept constant over time
    • 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
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/93—Measuring or controlling the joining process by measuring or controlling the speed
    • B29C66/934—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed
    • B29C66/93441—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed the speed being non-constant over time
    • 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
    • B65B51/20—Applying or generating heat or pressure or combinations thereof by fluid pressure acting directly on folds or on opposed surfaces, e.g. using hot-air jets
    • 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
    • B29C65/10—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using hot gases (e.g. combustion gases) or flames coming in contact with at least one of the parts to be joined
    • B29C65/103—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using hot gases (e.g. combustion gases) or flames coming in contact with at least one of the parts to be joined direct heating both surfaces 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
    • B29C66/70—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
    • 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
    • B29C66/826—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps without using a separate pressure application tool, e.g. the own weight of the parts to be joined
    • B29C66/8266—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps without using a separate pressure application tool, e.g. the own weight of the parts to be joined using fluid pressure directly acting on the parts to be joined

Definitions

  • This invention is concerned with packaging machines of the type
  • VFFS vertical form, fill and seal
  • each horizontal i2 seal is formed by a pair of cooperating sealing jaws which move with the i3 bag material while forming the seal and usually also while forming a ⁇ « horizontal cut to separate successive bags.
  • the horizontal seals may be i6 formed by cooperating rotary sealing jaws (or rotary double jaws forming i7 two seals during each revolution) or by cooperating sealing jaws which is move in a constant orientation along a D-shaped path so as to remain in i9 contact with the bag material while moving through a predetermined
  • the web of bag-forming material is driven downwards at a
  • variable-speed blower which automatically varies the velocity of the hot
  • the speed of ⁇ the sealing jaws is preferably also varied cyclically. During each cycle,
  • the web speed may be
  • 9 jaws may be decreased to increase the bag length.
  • a range ⁇ o of bag lengths may be achieved by suitable control of the speed patterns ⁇ of both the web and the sealing jaws, the only essential criterion in a i2 continous-motion machine being that the speeds should be equal while i3 the sealing jaws are in contact with the bag material.
  • the speed of the hot air blower may be stepped between two is levels, one corresponding to the speed of the web during sealing, and i6 the other to the speed or average speed of the web between successive i7 sealing operations.
  • the blower is driven by a is variable speed motor which is continuously controlled by an inverter i9 control circuit in response to the speed of the web.
  • This invention enables a substantially uniform longitudinal seam to
  • the air heating section of the hot air gun is preferably maintained
  • Figure 1 is a side view of the hot and cold air blowing
  • Figure 2 is a view from the right of Figure 1 , showing the nozzles
  • Figure 3 is a plan view of part of the apparatus.
  • FIG. 7 shows a hot air gun 10 into which air is blown through a ⁇ duct 12 by a suitable blower represented diagramatically as item 13.
  • 9 Power is supplied to the gun 10 by a cable 14, and the gun includes a ⁇ o temperature adjuster 16.
  • ⁇ Hot air from the gun 10 enters a hollow body 18 having a side i2 outlet formed by converging walls 18A and 18B (see particularly Figure i3 3) leading to a narrow nozzle portion formed by closely spaced parallel i4 walls 20 and 22 (see Figure 2).
  • the walls 20 and 22 may be spaced is apart, for example, by 2mm or less.
  • a hot air jet is thus directed from the i6 nozzle towards the overlapping edges of a web of packaging material 23 i7 formed into a tube around a cylindrical former 24 ( Figure 3) , the is overlapping edges being in the region 23A. i9 Immediately after passing the hot air nozzle, the seam is secured
  • the nozzle 26 may comprise
  • the nozzle 26 may direct
  • the hot air nozzle 1 0 may be one
  • variable-speed blower including a variable speed motor, may
  • the cold air nozzle or "air knife” may be of a type manufactured by
  • the nozzle for which purpose the outer edges of the nozzle walls are 1 recessed within the outer surfaces of the cheeks 32,34, which may be
  • Figure 3 shows the hot air nozzle in a retracted position allowing a
  • the bag-forming material may be drawn along the former 24, for i2 example, by means of bands on opposite sides of the mandrel which i3 may drive the material with the aid of suction applied through apertures i4 in the bands.
  • bands possibly without suction
  • the longitudinal seam forming apparatus is i9 mounted on a horizontal rod 38. It can be set at various positions along
  • This invention may also be applied to an intermittent machine, that
  • the web speed preferably varies cyclically in a predeterminable

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Fluid Mechanics (AREA)
  • Containers And Plastic Fillers For Packaging (AREA)

Abstract

A VFFS (vertical form, fill and seal) packaging machine, in which a web of bag-forming material (23) is driven downwards at a cyclically varying speed around a former (24) to overlap the edges of the web, and including a hot air device (10) for directing hot air onto the overlapping edges so as to seal them, characterised in that the hot air device (10) is supplied with air by a variable-speed blower (13) which automatically varies the velocity of the hot air directed towards the edges of the web, depending upon the speed of the web.

Description

ι Packaging Machine
2
3 This invention is concerned with packaging machines of the type
* commonly referred to as a VFFS (vertical form, fill and seal) packaging
5 machine. An example of such a machine is described in British patent β specification No. 2056940. That specification describes a machine of
7 the type in which horizontal seals are formed intermittently and in which β the tube of bag forming material is accordingly fed intermittently. The
9 present invention is concerned particularly (though not exclusively) with ιo a machine of the type described in which the bag-forming material is fed ιι continuously or substantially continuously, and in which each horizontal i2 seal is formed by a pair of cooperating sealing jaws which move with the i3 bag material while forming the seal and usually also while forming a ι« horizontal cut to separate successive bags. is In a continuous motion machine, the horizontal seals may be i6 formed by cooperating rotary sealing jaws (or rotary double jaws forming i7 two seals during each revolution) or by cooperating sealing jaws which is move in a constant orientation along a D-shaped path so as to remain in i9 contact with the bag material while moving through a predetermined
20 straight-line path during which each seal is formed. The present
2i invention is more particularly concerned with machines including such
22 D-motion sealing jaws.
23 The longitudinal seam by which the edges of a web forming the 2« tube are joined may be achieved in various ways. In the past use has
25 been made of heated bands and there has also been a proposal
26 according to which hot air could be used to form the heat seal with
2 suitable packaging material of which an example is polythene. A prior
28 proposal involving the use of hot air is described in US patent
29 specification No. 5,466,326.
30 According to the present invention, in a machine of the type 3i described, the web of bag-forming material is driven downwards at a
32 cyclically varying speed around a former to overlap the edges of the web
33 (in simple overlap fashion or to form a butt joint), and the means for
34 sealing the overlapped edges longitudinally comprises a hot air device
35 for directing hot air onto the overlapping edges so as to seal them,
36 characterised in that the hot air device is supplied with air by a
37 variable-speed blower which automatically varies the velocity of the hot
38 air directed towards the edges of the web, depending upon the speed of 1 the web.
2 Downstream of the hot air device there is preferably means for
3 blowing cool air onto the seam to set the seal.
4 The web speed is varied cyclically in a controlled manner in order
5 to allow control of the bag length. For the same purpose, the speed of β the sealing jaws is preferably also varied cyclically. During each cycle,
7 between successive sealing operations, the web speed may be
8 increased to increase the bag length and/or the speed of the sealing
9 jaws may be decreased to increase the bag length. In practice a range ιo of bag lengths may be achieved by suitable control of the speed patterns π of both the web and the sealing jaws, the only essential criterion in a i2 continous-motion machine being that the speeds should be equal while i3 the sealing jaws are in contact with the bag material. i The speed of the hot air blower may be stepped between two is levels, one corresponding to the speed of the web during sealing, and i6 the other to the speed or average speed of the web between successive i7 sealing operations. Preferably, however, the blower is driven by a is variable speed motor which is continuously controlled by an inverter i9 control circuit in response to the speed of the web.
20 This invention enables a substantially uniform longitudinal seam to
2i be formed, notwithstanding variations in the speed of the bag-forming
22 material.
23 The air heating section of the hot air gun is preferably maintained
24 at a substantially constant but adjustable temperature. In contrast, the
25 disclosure of US patent 5,466,326 is based on control of the heating
26 element temperature and is not believed to be practically capable of
27 achieving as uniform a seam as can be achieved by the present
28 invention. The reason for this is that the temperature of a heating
29 element cannot be rapidly altered to allow the hot air temperature to
30 track the speed of the web. Alternatives described in US patent 3i 5,466,326 are also not believed to be as satisfactory as the present
32 invention in terms of allowing rapid control of the air sealing operation in
33 response to web speed. Furthermore, the application of cool air,
34 preferably in the form of a thin film of air, is believed to be important,
35 though other means of cooling the seam may alternatively be
36 substituted.
37 An example of a longitudinal seam forming arrangement
38 according to this invention is shown in the accompanying drawings. In l these drawings:
2 Figure 1 is a side view of the hot and cold air blowing
3 arrangements;
4 Figure 2 is a view from the right of Figure 1 , showing the nozzles
5 through which hot and cold air are blown; and
6 Figure 3 is a plan view of part of the apparatus.
7 Figure 1 shows a hot air gun 10 into which air is blown through a β duct 12 by a suitable blower represented diagramatically as item 13. 9 Power is supplied to the gun 10 by a cable 14, and the gun includes a ιo temperature adjuster 16. ιι Hot air from the gun 10 enters a hollow body 18 having a side i2 outlet formed by converging walls 18A and 18B (see particularly Figure i3 3) leading to a narrow nozzle portion formed by closely spaced parallel i4 walls 20 and 22 (see Figure 2). The walls 20 and 22 may be spaced is apart, for example, by 2mm or less. A hot air jet is thus directed from the i6 nozzle towards the overlapping edges of a web of packaging material 23 i7 formed into a tube around a cylindrical former 24 (Figure 3) , the is overlapping edges being in the region 23A. i9 Immediately after passing the hot air nozzle, the seam is secured
20 by a film of cool air directed towards it by a nozzle 26 supplied with cool
2i air via a tube 28. As shown in Figure 2, the nozzle 26 may comprise
22 three closely spaced parallel walls 26A so as to direct towards the seam
23 two thin films of cool air. Alternatively, however, the nozzle 26 may direct
24 a single film of air towards the seam and may be inclined to the centre
25 line of the seam so as to cover the entire width of the seam.
26 By way of example, the hot air nozzle 1 0 may be one
27 manufactured by Leister Elektro-Geratebau, of 6056 Kagiswil,
28 Switzerland, for example their device identified as the Leister Hot Air Tool
29 3000. The variable-speed blower, including a variable speed motor, may
30 also be of a type offered by the same company.
3i The cold air nozzle or "air knife" may be of a type manufactured by
32 Lechler. It may receive its air supply from the blower which supplies air
33 to the hot air nozzle, so that the air velocity will also vary according to the
34 bag material speed.
35 As shown in Figure 2, two non-metallic cheeks 32,34 are secured
36 to the outside surfaces of both of the walls 20,22 forming the hot air
37 nozzle. These cheeks prevent the packaging material from contacting
38 the nozzle, for which purpose the outer edges of the nozzle walls are 1 recessed within the outer surfaces of the cheeks 32,34, which may be
2 chamfered as shown in Figure 3.
3 Figure 3 shows the hot air nozzle in a retracted position allowing a
4 pivoted cover plate 36 to be moved into line with the nozzle. This s prevents hot air from the nozzle reaching the packaging material while e the machine is temporarily stationary. The hot air gun is maintained at a
7 constant working temperature even while the machine is temporarily β stationary, and the blower may be kept running at a slow speed. The
9 cover plate 36 is moved automatically, by a cam action, to the position in ιo line with the hot air nozzle when the nozzle is retracted. ιι The bag-forming material may be drawn along the former 24, for i2 example, by means of bands on opposite sides of the mandrel which i3 may drive the material with the aid of suction applied through apertures i4 in the bands. Alternatively, bands (possibly without suction) may be is used to pull the material forward and maintain it in tension while the i6 actual speed of the material is controlled by other means, for example i7 rollers upstream of the former 24. is As shown in Figure 3, the longitudinal seam forming apparatus is i9 mounted on a horizontal rod 38. It can be set at various positions along
20 the rod, by means of a clamp 40, to accommodate formers of different
2i sizes.
22 This invention may also be applied to an intermittent machine, that
23 is to say one in which the web stops to allow intermittently moving
24 sealing jaws to operate to form successive horizontal seals serving as
25 the top of each bag and the bottom of the next bag. The blower is
26 preferably arranged to run at a fixed low speed while the web is
27 stationary, and at a higher variable speed while the web is moving; as
28 before, the web speed preferably varies cyclically in a predeterminable
29 pattern to achieve the desired (adjustable) bag length.
30 31 32 33 34 35 36 37 38

Claims

i CLAIMS
2
3 1. A packaging machine of the type described, in which a
4 web of bag-forming material (23) is driven downwards at a cyclically
5 varying speed around a former (24) to overlap the edges of the web, and
6 including a hot air device (10) for directing hot air onto the overlapping
7 edges so as to seal them, characterised in that the hot air device (10) is β supplied with air by a variable-speed blower (13) which automatically
9 varies the velocity of the hot air directed towards the edges of the web, ιo depending upon the speed of the web.
11 i2 2. A machine according to claim 1 , including means (26) for i3 blowing cool air onto the seam downstream of the hot air device (10) to i4 set the seam.
15 i6 3. A machine according to claim 1 or claim 2, in which the i7 web of packaging material (28) is driven continuously at a cyclically is varying speed.
19
20 4. A machine according to claim 3, in which the blower speed
2i is continuously variable so as to increase when the web speed increases
22 and vice versa.
23
24 5. A machine according to claim 3, in which the blower is set
25 to operate at two or more set speeds.
26
2 6. A machine according to claim 1 or claim 2, in which the
28 web is arranged to be stopped at regular intervals while horizontal seals
29 are made which form the top of each bag and the bottom of the next
30 bag.
31
32 7. A machine according to claim 6, in which the hot air device
33 includes a nozzle which is arranged to move away from the web while
34 the web is stationary.
35
36 8. A machine according to claim 7, in which the blower is set
37 to run at a fixed low speed while the web is stationary and at a higher
38 variable speed while the web is moving. 1
2 9. A machine according to any one of claims 1 to 8, in which
3 the hot air device (10) including an air heating device which is
4 maintained at a constant but adjustable temperature.
5
6 10. A method of packaging products involving a machine of the
7 type described, in which a web of bag-forming material is driven β downwards at a cyclically varying speed around a former to overlap the 9 edges of the web, and a hot air device is arranged to direct a stream of ιo hot air onto the overlapping edges so as to seal them, characterised in ιι that the hot air device is supplied with air by a variable-speed blower i2 which automatically varies the velocity of the air directed towards the i3 edges of the web, depending upon the speed of the web.
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
EP98909581A 1997-03-07 1998-03-06 Packaging machine Withdrawn EP1015230A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB9704812.8A GB9704812D0 (en) 1997-03-07 1997-03-07 Packaging machine
GB9704812 1997-03-07
PCT/GB1998/000666 WO1998040202A1 (en) 1997-03-07 1998-03-06 Packaging machine

Publications (1)

Publication Number Publication Date
EP1015230A1 true EP1015230A1 (en) 2000-07-05

Family

ID=10808909

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98909581A Withdrawn EP1015230A1 (en) 1997-03-07 1998-03-06 Packaging machine

Country Status (4)

Country Link
EP (1) EP1015230A1 (en)
GB (1) GB9704812D0 (en)
WO (1) WO1998040202A1 (en)
ZA (1) ZA981988B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE515445C2 (en) * 1999-02-22 2001-08-06 Glenn Gustafsson Method and apparatus for wrapping soft elements
GB9922747D0 (en) 1999-09-24 1999-11-24 Molins Plc Method and apparatus for producing bags having a reclosable fastener
GB0020840D0 (en) 2000-08-23 2000-10-11 Molins Plc Heat sealing apparatus for packaging machinery
ITBO20020463A1 (en) * 2002-07-18 2004-01-19 Awax Progettazione APPARATUS FOR CONTINUOUS AND SEALING THERMAL WELDING OF LONGITUDINAL AND OVERLAPPING ELEMENTS OF TUBULAR ELEMENTS OF THERMOPLASTIC FILM OF SPES

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Publication number Priority date Publication date Assignee Title
US2678679A (en) * 1951-08-18 1954-05-18 Bergstein Frank David Bottom sealing means and method for plastic bags
GB1260467A (en) * 1968-02-15 1972-01-19 British United Shoe Machinery Improvements in or relating to the application of adhesive and machines for use therein
US3775222A (en) * 1970-04-14 1973-11-27 Pembroke Carton & Printing Co Heat sealing apparatus
GB1396502A (en) * 1971-06-24 1975-06-04 Drg Packaging Ltd Heat sealing
US3916598A (en) * 1974-10-15 1975-11-04 Du Pont Synchronized tube forming and filling machine for forming chub packages
US4218863A (en) * 1978-11-22 1980-08-26 American Can Company Continuous motion wrapping machine
US4440588A (en) * 1982-03-01 1984-04-03 Stevenson Edward J Hot air welder for welding roofing material
CA1248437A (en) * 1983-12-13 1989-01-10 Dana M. Boyd Process for heat sealing thermoplastic film and apparatus therefor
DE3514714A1 (en) * 1985-04-24 1986-10-30 Rovema Verpackungsmaschinen GmbH, 6301 Fernwald Process for the production of packaging, and packaging machine
US4834828A (en) * 1987-04-30 1989-05-30 Engineered Construction Components Machine for welding roof membranes
US5466326A (en) * 1992-10-14 1995-11-14 Hayssen Manufacturing Company Continuous motion heat seal control

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9840202A1 *

Also Published As

Publication number Publication date
WO1998040202A1 (en) 1998-09-17
GB9704812D0 (en) 1997-04-23
ZA981988B (en) 1999-09-09

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