Improved packaging method and apparatus

Abstract

A method of packaging items is provided. The method comprises providing a mesh sheet (50) having first and second outer edges (52,54), and feeding the 5 mesh sheet and one or more items to be packaged into a packaging apparatus. The first and second outer edges (52,54) of the mesh sheet (50) are guided towards one another within the packaging apparatus such that a generally tubular mesh is formed about the one or more items. The first and second outer edges (52,54) of the mesh sheet (50) are attached directly to one another so as 10 to form a longitudinal seal (60). First and second end seals are formed in the mesh (50) such that the one or more items are sealed within the mesh by the longitudinal seal (60) and the end seals. An apparatus suitable for applying the method is also provided.

Description

Field of the Invention The present invention is concerned with the field of packaging. More specifically, the present invention provides improved packaging for loose items such as, for example, fruit and vegetables as well as a method of manufacturing same. Background of the Invention Netting has been employed for many years in packaging applications, and particularly in the packaging of loose food items such as fruit and vegetables, for example. The tubular netting is formed into a bag into which one or more items are placed before an open end of the bag is closed with either a metal or plastic clip or with an ultrasonic weld seal. However, the processes and apparatus used to pack items in netting are comparatively inefficient and costly to maintain, and the netting used is not especially easy to recycle. Packs integrating an element of polyolefin open mesh have been presented as a solution to these shortcomings with netting. The mesh is formed into a bag or net into which one or more items are placed before at least one open end of the bag is closed with an ultrasonic or heat-melt weld seal. These mesh packs are integrally formed with a polymer film component which may reinforce the packaging, provide or strengthen the sealing of the pack, and / or carry printed information relating to the products contained in the packaging. Packaging items using this combination of mesh and film adds to the cost and plastic content of the packaging. This mesh and film combination has therefore been found to be cost-prohibitive and also unpopular with consumers who expect items such as onions and the like to be packaged in traditional netting, which may result in those consumers selecting a different product in a shop or supermarket. It is an aim of the present invention to obviate or mitigate one or more of these disadvantages with existing packaging. Summary of the Invention According to a first aspect of the present invention there is provided a method of packaging items, the method comprising: providing a mesh sheet having first and second outer edges; feeding the mesh sheet and one or more items to be packaged into a packaging apparatus; guiding the first and second outer edges of the mesh sheet towards one another within the packaging apparatus such that a generally tubular mesh is formed about the one or more items; sealing the first and second outer edges of the mesh sheet directly to one another so as to form a longitudinal seal; and forming first and second end seals in the mesh such that the one or more items are sealed within the mesh by the longitudinal seal and the end seals. Preferably, the step of sealing the first and second outer edges comprises bringing upper surfaces of the first and second outer edges directly together so as to form a fin seal. Alternatively, the step of sealing the first and second outer edges comprises bring an upper surface of the first outer edge directly together with a lower surface of the second outer edge so as to form an overlap seal. The method may further comprise the step of applying heat to at least part of the sealed mesh so as to shrink the mesh around the one or more items. Preferably, the step of applying heat comprises directing the sealed mesh past at least one heating device and selectively applying heat from the at least one heating device to one or more specific portions of the sealed mesh. Preferably, the step of selectively applying heat comprises selectively activating the at least one heating device based upon a sensed position of the sealed mesh relative to the at least one heating device. Preferably, the step of selectively applying heat comprises providing one or more heat guards between the at least one heating device and the sealed mesh. In one preferred embodiment the one or more heat guards are static and positioned adjacent the at least one heating device. In an alternative embodiment the one or more heat guards move with the sealed mesh relative to the at least one heating device. The method may further comprise the step of rotating the sealed mesh about the vertical axis in the vicinity of the at least one heating device such that heat is applied to the ends of the sealed mesh. Preferably, the mesh sheet comes from a roll of mesh, and the method further comprises the step of cutting the mesh as the second end seal is applied so as to separate the sealed mesh from the roll of mesh. The method may further comprise attaching one edge of a printed film to the mesh sheet prior to the guiding step, the printed film forming a label which may rotate about the attached edge such that printed information on both sides of the label can be viewed. Preferably, the printed film and mesh are formed from the same plastics material. According to a second aspect of the present invention there is provided a packaging apparatus comprising: a first end configured to receive a mesh sheet and one or more items to be packaged; one or more guide members configured to guide first and second outer edges of the mesh sheet towards one another such that a generally tubular mesh is formed about the one or more items; a longitudinal sealing unit configured to seal the first and second outer edges directly to one another so as to form a longitudinal seal; an end sealing unit configured to form first and second end seals in the mesh such that the one or more items are sealed within the mesh by the longitudinal seal and end seals; and a conveying mechanism configured to move the mesh sheet and items through the apparatus. The apparatus may further comprise at least one heating device configured to apply heat to one or more areas of the conveying mechanism downstream of the end sealing unit. The apparatus may further comprise a controller and at least one position sensor configured to monitor the position of the sealed mesh on the conveying mechanism, wherein the controller selectively activates the at least one heating device in response to signals from the at least one position sensor. The apparatus may further comprise one or more heat guards positioned between the at least one heating device and the conveying mechanism. In one embodiment the one or more heat guards are configured to move with the conveying mechanism relative to the at least one heating device. The apparatus may further comprise a rotating mechanism adjacent the at least one heating device, wherein the rotating mechanism is configured to rotate the sealed mesh about the vertical axis relative to the heating device and conveying mechanism. The apparatus may further comprise a cutter configured to cut the mesh as the second end seal is applied. The cutter may be integrally formed with the end sealing unit. The apparatus may further comprise a labelling unit located between the first end and one or more guide members, the labelling unit configured to attach one edge of a printed film label to the mesh prior to the one or more guide members. Brief Description of the Drawings A preferred embodiment of the present invention will now be described, by way of example only, with reference to the following drawings: Figure 1 shows a horizontal flow wrapping apparatus; Figure 2 shows a vertical flow wrapping apparatus; Figure 3 is a detail view of how mesh packaging is formed using either the horizontal or vertical flow wrapping apparatus; Figure 4 is an end view of mesh packaging incorporating a longitudinal fin seal; and Figure 5 is an end view of mesh packaging incorporating a longitudinal lap seal. Detailed Description of the Drawings The present invention employs a horizontal or vertical flow wrapping process in order to wrap loose products in packaging formed from a polyolefin mesh. The mesh is preferably a cross laminated, non-woven polyolefin mesh. Whilst such meshes are already known the present invention utilises mesh alone, without any reinforcing film elements, in order to form the packaging. Figure 1 illustrates an exemplary horizontal flow wrapping apparatus 1 which may be used in order to form packaging according to the present invention. A roll of mesh 2 to be used in the packaging is fed over one or more feed rollers 4 in order that the mesh arrives at a wrapping section 6 of the apparatus with a desired tension. A product 8 which is to be wrapped is fed to the wrapping section 6 by a conveyor (not shown) or similar delivery means. As described above, the present invention is ideally suited to the wrapping of loose produce such as fruit and vegetables but may equally be employed to wrap any kind of loose item. An upstream end of the wrapping section 6 has one or more forming members 10, where the, or each, forming member includes one or more guides (not shown) which guide the mesh into a desired shape for forming the packaging. Immediately downstream of the forming member(s) 10 are one or more seal rollers 12. Each seal roller 12 is heated and forms the seal that runs longitudinally along the packaging so as to enclose the product 8. The longitudinal seal may be a fin seal or a lap seal, both of which are described below with reference to Figures 4 and 5. The final components in the wrapping section 6 are an end sealer and a cutter 14. The end sealer and cutter may be separate from one another but in the preferred embodiment illustrated they are integrally formed in upper and lower sealing members 16,18. The sealing members 16,18 move toward and away from one another and when the two sealing members 16,18 come together they seal a front end of the mesh packaging, either by applying heat or an ultrasonic weld. The two sealing members 16,18 then are moved apart for a predetermined period of time wherein the desired number of products to be packaged in a single pack pass between the sealing members. The sealing members 16,18 are then brought back together to seal the rear end of the mesh packaging in the same manner as the front end seal, and one or more cutting elements (not shown) provided on one or both sealing members then separates the fully formed pack from the mesh further upstream in the wrapping section 6. A final, formed mesh pack 20 containing the product(s) can then be conveyed to a packing station for final packing, storage and / or transportation to a point of sale. Figure 2 illustrates a vertical flow wrapping apparatus 21 which may also be used in order to form packaging according to the present invention. This vertical flow wrapping apparatus 21 has generally the same componentry and packaging process steps as employed in the horizontal flow wrapping apparatus 1. The obvious main distinction between the two apparatus being the horizontal or vertical orientation of the apparatus and related packaging process employed. A roll of mesh 22 to be used in the packaging is fed over one or more feed rollers 24 in order that the mesh arrives at a wrapping section 26 of the apparatus with a desired tension. A product (not shown in Figure 2) which is to be wrapped is gravity fed to the wrapping section 26 by a filling tube 27. An upstream end of the wrapping section 26 has one or more forming members 30, where the, or each, forming member includes one or more guides 31 which guide the mesh into a desired shape for forming the packaging. Immediately downstream of the forming member(s) 30 are one or more longitudinal sealing units 32. The, or each, longitudinal sealing unit 32 applies heat so as to form the seal that runs longitudinally along the packaging so as to enclose the product 28. The longitudinal seal may be a fin seal or a lap seal. One or more pairs of traction belts 29 is also provided to draw the mesh downwards. The final components in the wrapping section 26 are an end sealer and cutter. The end sealer and cutter may be separate from one another or else may be integrally formed in a pair of end sealing members 36,38. The sealing members 36,38 move toward and away from one another and when the two sealing members 36,38 come together they seal a front end of the mesh packaging, either through the application of heat or an ultrasonic weld. Then the two sealing members 36,38 are moved apart for a predetermined period of time wherein the desired number of products to be packaged in a single pack pass between the sealing members. The sealing members 36,38 are then brought back together to seal the rear end of the mesh packaging in the same manner as the front end seal, and one or more cutting elements (not shown) provided on one or both sealing members then separates the fully formed pack from the mesh further upstream in the wrapping section 36. A final, formed mesh pack 40 containing the product(s) can then be conveyed to a packing station for final packing, storage and / or transportation to a point of sale. Figure 3 illustrates one way in which the mesh can be guided by the forming member(s) in order to package a product. The components of the wrapping apparatus are omitted for clarity in Figure 3, but this guidance as described below may be used in either the horizontal or vertical wrapping apparatus. The mesh comes off the supply roll in a substantially planar sheet 50 upstream of the wrapping section and forming member(s) therein. The forming member(s) guide outer edges 52,54 of the mesh sheet 50 upwards and inwards towards one another such that the mesh takes a generally tubular form. As shown in Figures 4 and 5 the forming member(s) can be arranged such that the outer edges 52,54 form a longitudinal fin seal or lap seal 60. With the fin seal 60F shown in Figure 4, upper surfaces 53,55 of the respective outer edges 52,54 are brought into contact with one another and then the seal roller or sealing unit of the apparatus seals these upper surfaces 53,55 to one another to form a longitudinal seam along the packaging. As the name suggests, a fin seal extends radially outwards from the exterior of the packaging and runs longitudinally along the packaging. A lap seal 60L is also formed when the outer edges 52,54 are brought together by the forming member(s) to form packaging with a generally tubular profile. However in this instance, and as illustrated in Figure 5, the outer edges 52,54 end up overlapping one another with an upper surface 55 of one outer edge 54 lying over a bottom surface 56 of the other outer edge 52. Once the surfaces 55,56 are positioned as shown, the seal roller or sealing unit seals the surfaces to one another so as to form a generally flush longitudinal seal along the packaging. The present invention preferably uses carefully selected, developed and tested grades of cross laminated polyolefin non-woven open mesh to wrap around food and non-food products. However, any other suitable plastics open mesh may be used instead. The present invention creates a high-performance pack which can be used in form-fill-and-seal applications without the need for an integrated polymer film to reinforce the pack or contribute to the pack integrity. This is achieved through either a horizontal or vertical wrapping format, with the edges of the mesh directly attached to one another without any intermediary material used to strengthen the pack or seal. Directly attaching the opposing edges of the mesh forms a fin or lap seal running the length of the pack and an end seal is provided at either end of the pack. The present invention also provides more aesthetically-pleasing net-style packaging for the consumer by employing a horizontal flow wrapping process in particular. This process utilises side control, overhead control, special supportive in-feed conveyors and gusseting to provide the tightest possible pack. The packaging of the present invention may be further improved via the optional use of heat shrinking, where heat is directed at specific parts of the pack during the packaging process so as to heat shrink selected parts of the pack and further improve the appearance of the packaging. To this end the wrapping machine employed in the packaging process may be modified to include a heated tunnel or channel within which the heat shrinking is carried out. Such a heat shrink process is configured to ensure that only specific controlled areas of the sealed pack are shrunk. If heat is simply applied to the entire pack the mesh may distort or break, particularly where gaps exist between items in a particular pack. Any labelling already applied to the pack may also distort or be otherwise damaged, rendering the label at least partially illegible. In one preferred embodiment, once the sealing and cutting process described above has been completed one or more sensors are used to identify the position of the ends of the sealed pack on a belt or similar pack-conveying mechanism, as well as the travel speed of the conveying mechanism. A controller receives the position and speed information from the sensors and subsequently activates one or more heat guns or similar heating devices located downstream of the sensors. Based on this sensor information the controller is able to determine when specific portions of the pack are passing the heating device(s) and hence only apply heat, and achieve shrinkage, in targeted areas of the pack. For example, this may be to only apply heat to the portions of a pack where a packaged item is located and not to any areas between the items. In this way the pack is shrunk tightly about the packaged items but the areas of the mesh between the items are not overly shrunk and damaged or broken. The shrinkage method described above relies on pulses of heat being applied as certain regions of a pack pass by the heating device(s). The heating device(s) may apply pulses of heat directly to a given location on the conveying mechanism. Alternatively, one or more static heat guards may be positioned between the heating device(s) and the conveyor so that heat can only reach certain locations on the conveyor. In an alternative arrangement, the heating device(s) may be active for a more prolonged period, or indeed be constantly active and generating heat. In such circumstances, the conveying mechanism may further comprise one or more mobile heat guards. These guards may move with the belt or other conveying component, where the position of the guards is synchronised with a position of the pack on the belt as it moves downstream from the sealing / cutting station. As such, when the pack and accompanying heat guards reach the heating device(s) the heat from the device(s) can only act upon selected regions of the pack. The conveying mechanism is controlled and synchronized in the longitudinal direction by the controller. A rotating mechanism may also be employed in the vicinity of the heating device(s). The rotating mechanism may be passive guides which act to rotate the pack as it passes the guides on the conveying mechanism. Alternatively, the rotating mechanism may be an active mechanism which employs one or more arms, for example, to lift and rotate the pack on the conveying mechanism. In either form the rotating mechanism is configured to rotate the pack about the vertical axis through at least 90 degrees. This results in the pack lying perpendicular to the direction of the conveying mechanism as it passes the heating device(s). If heating devices are placed on opposite sides of the conveying mechanism heat can therefore be applied to the ends of the pack simultaneously before the pack continues downstream The present invention also provides an advantage when it comes to labelling the packages, as it removes the need for the polymer film and any form of attached label, such as the “wine glass”-shaped labels commonly attached to net or mesh packaging. In the present invention a piece of polymer film may be attached by heat seal, adhesive or ultrasonic weld to a portion of the mesh inline on the flow-wrapping machine prior to the forming of the pack around the packaged items. Only one end of this polymer film label is attached to the mesh, so that it can be printed on both sides and be a two sided label. With the present invention the label is not attached to the pack using the end seal of the pack unlike other packs currently on the market. The label is made from the same type of plastic as the mesh to ensure complete recyclability of the whole pack. This process allows many shapes and sizes of label to be used as there are no restrictions dictated by the label having to perform a reinforcement function as in the current mesh and film packs. It also removes the need for the extra tag element provided on the current “wine-glass” labels, thus reducing the amount of material required. It also enables use of a thinner material and an associated reduction in plastic weight, e.g. a 50%. The attachment area for the label of the present invention is larger and the label itself can be smaller as it is less likely to be used as a handle by the consumer, thus reducing the need for strength in the label material. The present invention provides a pack that does not rely on or use polymer film to reinforce the pack or contribute to the pack integrity. The present invention does not require the use of any polymer film in the formation of the pack itself. The processes of the present invention provide solutions to the problem of pack presentation and tightness, using carefully designed wrapping processes and also optionally using the innovative targeted application of heat. New labelling solutions also drastically reduce the weight of plastic required and also the cost of the pack. Finally, the present invention has greatly improved wrapping / sealing speeds and efficiencies in comparison to current netting pack processes with reduced packaging and production costs as a result, whilst still producing a pack which is cheaper to produce and more attractive to consumers than packs combining mesh and film. The concept of forming a pack purely from an open plastics mesh has not been disclosed before, and the market bias would consider that the seal integrity of such a pack would not be sufficient for the demands of the application. In addition to this, such a solution would in itself have no labelling facility and would not hold the 5 products tight in the way that existing elastic netting solutions do. The present invention provides solutions to each of these problems or prejudices in the market. Modifications and improvements made be incorporated without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method of packaging items, the method comprising:providing a mesh sheet having first and second outer edges;feeding the mesh sheet and one or more items to be packaged into a packaging apparatus;guiding the first and second outer edges of the mesh sheet towards one another within the packaging apparatus such that a generally tubular mesh is formed about the one or more items;sealing the first and second outer edges of the mesh sheet directly to one another so as to form a longitudinal seal; andforming first and second end seals in the mesh such that the one or more items are sealed within the mesh by the longitudinal seal and the end seals.

2. The method of claim 1, wherein the step of sealing the first and second outer edges comprises bringing upper surfaces of the first and second outer edges directly together so as to form a fin seal.

3. The method of claim 1, wherein the step of sealing the first and second outer edges comprises bring an upper surface of the first outer edge directly together with a lower surface of the second outer edge so as to form an overlap seal.

4. The method of any preceding claim, further comprising the step of applying heat to at least part of the sealed mesh so as to shrink the mesh around the one or more items.

5. The method of claim 4, wherein the step of applying heat comprises directing the sealed mesh past at least one heating device and selectively applying heat from the at least one heating device to one or more specific portions of the sealed mesh.

6. The method of claim 5, wherein the step of selectively applying heat comprises selectively activating the at least one heating device based upon asensed position of the sealed mesh relative to the at least one heating device.

7. The method of claim 5 or claim 6, wherein the step of selectively applying heat comprises providing one or more heat guards between the at least one heating device and the sealed mesh.

8. The method of claim 7, wherein the one or more heat guards are static and positioned adjacent the at least one heating device.

9. The method of claim 7, wherein the one or more heat guards move with the sealed mesh relative to the at least one heating device.

10. The method of any of claims 5 to 9, further comprising the step of rotating the sealed mesh about the vertical axis in the vicinity of the at least one heating device such that heat is applied to the ends of the sealed mesh.

11. The method of any preceding claim, wherein the mesh sheet comes from a roll of mesh, and the method further comprises the step of cutting the mesh as the second end seal is applied so as to separate the sealed mesh from the roll of mesh.

12. The method of any preceding claim, further comprising attaching one edge of a printed film to the mesh sheet prior to the guiding step, the printed film forming a label which may rotate about the attached edge such that printed information on both sides of the label can be viewed.

13. The method of claim 12, wherein the printed film and mesh are formed from the same plastics material.

14. A packaging apparatus comprising:a first end configured to receive a mesh sheet and one or more items to be packaged;one or more guide members configured to guide first and second outer edges of the mesh sheet towards one another such that a generally tubular mesh is formed about the one or more items;a longitudinal sealing unit configured to seal the first and second outer edges directly to one another so as to form a longitudinal seal;an end sealing unit configured to form first and second end seals in the mesh such that the one or more items are sealed within the mesh by the longitudinal seal and end seals; anda conveying mechanism configured to move the mesh sheet and items through the apparatus.

15. The apparatus of claim 14, further comprising at least one heating device configured to apply heat to one or more areas of the conveying mechanism downstream of the end sealing unit16. The apparatus of claim 15, further comprising a controller and at least one position sensor configured to monitor the position of the sealed mesh on the conveying mechanism, wherein the controller selectively activates the at least one heating device in response to signals from the at least one position sensor.

17. The apparatus of either claim 15 or claim 16, further comprising one or more heat guards positioned between the at least one heating device and the conveying mechanism.

18. The apparatus of claim 17, wherein the one or more heat guards are configured to move with the conveying mechanism relative to the at least one heating device.

19. The apparatus of any of claims 15 to 18, further comprising a rotating mechanism adjacent the at least one heating device, wherein the rotating mechanism is configured to rotate the sealed mesh about the vertical axis relative to the heating device and conveying mechanism.

20. The apparatus of any of claims 14 to 19, further comprising a cutter configured to cut the mesh as the second end seal is applied.

21. The apparatus of claim 20, wherein the cutter is integrally formed with the5 end sealing unit.

22. The apparatus of any of claims 14 to 21, further comprising a labelling unit located between the first end and one or more guide members, the labelling unit configured to attach one edge of a printed film label to the mesh prior to 10 the one or more guide members.

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