AU2008212006A1

AU2008212006A1 - A bag

Info

Publication number: AU2008212006A1
Application number: AU2008212006A
Authority: AU
Original assignee: Amcor Pty Ltd
Current assignee: Amcor Pty Ltd
Priority date: 2008-09-04
Filing date: 2008-09-04
Publication date: 2010-03-18
Also published as: AU2010100368A4

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant (s): AMCOR LIMITED Invention Title: A BAG The following statement is a full description of this invention, including the best method for performing it known to me/us: P78815.AU PatSetFiling Applcaion 008-9-1.doc (M) -2 A BAG FIELD OF THE INVENTION 5 The present invention relates to bags such as bulk bags that are often used for bulk packaging of products and liner bags for bulk bags. Bulk bags are also known in the art as Flexible Intermediate Bulk Containers (FIBC). 10 BACKGROUND OF THE INVENTION Typically, bulk bags are understood herein to mean sacks that are used to package large volumes of 15 material, for example and without limitation, the bags may have dimensions ranging up to 1 m wide by 1 m across and by 1 to 2 m in height. Bulk bags can also be used to carry weights of up to 3000 kg or more. Bulk bags can also be open or closed at the top, and can be intended for 20 a single trip, or be reused. Applications for bulk bags include transporting a range of products including food products, industrial products and commodities such as iron ore. 25 Bulk bags are typically made out of polypropylene, of about 200 grams per square metre. In many cases this polypropylene material is in the form of a laminate comprising a layer formed from strands of polypropylene woven together, with another layer of the 30 laminate comprising a polymer film made from polypropylene or other suitable polymers. The purpose of the woven structure is to provide the strength necessary to support the bag, and also to increase the ability of the bulk bag to resist tears and nicks compared to a homogeneous film. 35 The purpose of the polymer film is help seal the bulk bag so the contents do not leak out through the woven structure, to create an impermeable material. A second N3\Melbourne\CaseB\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 -3 reason for the tight sealing of bulk bags is to prevent the ingress of moisture, which can damage the contents of the bulk bags. 5 Other techniques are known in the art to improve the seal where adjacent edges of material are joined so the contents of the bag are fully contained and the bag is impermeable or very close to being impermeable. 10 Other bulk bags may also have an internal liner that is used within the bag to help keep the product clean and not contaminated from the material of the bag, or for other functional purposes. Inner liners are typically used in conjunction with the bulk bags formed from a 15 porous polypropylene material, i.e. a material formed from strands of polypropylene woven together but without a second film layer laminated to the woven material to improve the sealing of the bag. This additional sealing is not required as the inner liner seals the contents of the 20 bulk bag. Bulk bags often comprise straps which are used to lift the bags. They can also comprise areas of removable material in the top and bottom panels of these bags to 25 help fill and empty the bags. Bulk bags are often closed to help retain the contents of the bulk bag within the bag. Either the bulk bag itself, the inner liner, or both components can be 30 closed. In recent years the technologies used to seal bulk bags has advanced to the point where the high quality of the soal is causing the following problems: 35 a) Air may be trapped within the bag during filling resulting in the formation of air bubbles within N:\Melbourne\Cases\Patent\78000-78999\P78815.AU\Speci\P78815 3 Sept 08.doc 04/09/06 - 4 the bag and causing the bag not to sit flat on the floor. Sometimes bags suffering from this fault have been known to roll over, which is very undesirable considering their size and contents. 5 Air bubbles can also cause problems if the bags are stacked. b) The bag can be slow to fill. 10 It is an object of the present invention to provide an alternative and improved bulk bag. SUMMARY OF THE INVENTION 15 According to the present invention there is provided a bag that, for example, may be in the form of a bulk bag or a liner for a bulk bag, the bag comprising a base, side walls extending from the base, and a top wall having an inlet through which material can be loaded into 20 the bulk bag, the walls of the bag being substantially impervious to air and having one or more than one air vent assembly, the or each air vent assembly including i) an air vent formation that allows the passage of air through the wall of the bag; 25 and ii) porous material on or covering the air vent formation which allows the passage of air in and/or out of the bag during filling or emptying of the bag but substantially 30 prevents the passage of material in the bag through the air vent assembly. The porous material may prevent the passage of dust particles into or out of the bag. In other words the 35 porous material may have good dust filtration properties. In an embodiment, the air vent formation in the N:\Melbourne\Casea\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 -5 top and/or side walls of the bag is formed by piercings, perforations or openings in the walls. Suitably, the piercings, perforations or openings may be in the form of slits or cutouts in the impervious walls. 5 In an embodiment, the piercing or perforations of each air vent formation of the side and/or top wall is in the form of one or more slits having a length ranging between 50 to 100 mm. 10 In an embodiment, the piercing or perforations of each air rent formation of the side and/or top wall is in the form of cutouts of these material, suitably between 4 to 10 cutouts each in the range of 1 to 2cm square. 15 According to yet another embodiment, the air vent formation may be in the form of one or more than one air valves, and suitably one-way air valve assemblies. 20 Although the porous material may be of any size so as prevent the movement of the contents of the bulk bag through the air vent assembly, suitably the porous materials is at least 50cm2 and even more suitably approximately 100cm 2 . For instance, the porous material 25 may cover a square about 10 cm in width and breadth. In another embodiment, the porous material is folded al: one or more than one position to increase the surface area of the porous material covering the air 30 ventilation formations. In an embodiment, suitably the porous material is hydrophobic so as to minimise the ingress of moisture into the bag. 35 N:\Melbourne\Casea\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 -6 Bulk Bag In the situation in which the bag is in the form of an impervious bulk bag, suitably the porous material is 5 disposed on either one or a combination of the inner or outer faces of the top and/or side walls. According to an embodiment of the invention, the porous material is located on both the inner and outer faces of the walls. 10 In an embodiment, the porous material comprises a woven or non-woven fabric. In an embodiment, the sheet of porous material is joined to the walls near the edges of the porous material 15 by sewing or stitching. Any other suitable fastening technique may also be employed such as adhesives, rivots and heat or melt sealing. Liner Bag 20 In an embodiment, the porous material is a mesh, such as nylon mesh with the mesh spacings ranging from 05. to 2.0mm and suitably approximately 1 mm 25 The air vent formation of the walls of the bag may include a one-way valve. The one-way valve can reduce the entry of moisture through the air vent assembly and into the contents of the bag. 30 However according to alternative embodiment the air vent assembly includes a further layer of material, suitably a polymeric film that is heat welded, heat sealed or glued to the outside of the bag walls to form a pouch, and the further layer of material includes a further air 35 vent formation, suitably a one-way valve. The air vent formations in the walls of the bag may be piercings, perforations or other openings. N:\Melbourne\Caees\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 0.doc 04/09/08 -7 The materials used to form side walls, top panel or bottom panel of the bulk bag can be made of any suitable material, which may include natural materials 5 such as cotton and hemp. The bulk bag may have any volume, including volumes ranging from 0.5 to 2.5 cubic meters and suitably, volumes ranging from 1.0 to 1.5 cubic meters. 10 In another embodiment the bulk bag includes a means for emptying the bags from their bottom, for example, the base of the bag may include a plug or open and closeable panel that can be moved to help empty the 15 bags. According to the present invention there is provided a bulk bag comprising a base, side walls extending from the base, and top panel, where one or more 20 of these panels of the bag comprise one or more than one air vent assemblies formed from a sandwich of one or more layers of a sheet of porous material joined to an area of the panel, and where the area of the panel of the bulk bag that is being used as part of the air vent assembly has 25 been pierced or perforated to allow air to flow through this material in a controlled manner. According to the present invention there is provided a bag that, for example, may be in the form of a 30 bulk bag or a liner for a bulk bag, the bag comprising a base, side walls extending from the base, and a top wall having an inlet through which material can be loaded into the bulk bag, the top and/or the side walls of the bag being substantially impervious to air except for one or 35 more than one region of the top and/or side walls that is air permeable but substantially prevents the passage of dust particles through the region N:\Melbourne\Cases\Patent\78000-78999\P78815.AU\Speci\P78815 3 Sept 08.doc 04/09/08 -8 According to the present invention there is provided a bag that, for example, may be in the form of a bulk bag or a liner for a bulk bag, the bag comprising a 5 base, side walls extending from the base, and a top wall having an inlet through which material can be loaded into the bulk bag, the walls of the bag being substantially impervious to air except for one or more than one region of the walls that has an air vent assembly, and wherein 10 each air vent assembly comprises one or more sheets of porous material which allows the passage of air during filling and/or emptying of the bag but substantially prevents the movement of the contents of the bulk bag through the air vent assembly, and an air vent formation 15 that allows the passage of air through the othersise substantially impermeable wall of the bag but by itself does not prevent the movement of the contents of the bag through the air vent assembly 20 BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described further with reference to the accompanying drawings, of which: 25 Figure 1 is a perspective view of a bulk bag having air vent assemblies located on a top wall of the bag and a side wall of the bag according to an embodiment of the present invention; Figure 2 is plan view of the bag shown in Figure 30 1; Figure 3 is a detailed view of one of the air vent assemblies shown in Figures 1 and 2; Figure 4 is a cross-sectional view through the arrows A-A of the ventilation points shown in Figure 3; 35 Figure 5 is a perspective view of a bag liner for a bulk bag while open or not sealed, with the liner having air vent assemblies; Ns\Melbourne\Cases\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 - 9 Figure 6 is a perspective view of the bag liner shown in Figure 5 in a closed or sealed state and with the air vent assemblies located in the top and side walls; Figure 7 a detailed view of one of the air vent 5 assemblies shown in Figures 6 and 7; and Figure 8 is a cross-sectional view of the arrows B-B of the air vent assemblies shown in Figure 7. DETAILED DESCRIPTION 10 Figure 1 illustrates a perspective view of bulk bag 10 according to an embodiment of the invention having dimensions ranging up to 1 m wide by 1 m across and by 1 to 2 m in height. The bulk bag 10 can be used to carry 15 weights of up to 3000 kg or more. The bag 10 includes a base 11, side walls 12 extending from the base 11, and a top wall 13 having an inlet 14 for loading material into the bag 10. The base 20 11 and side walls 12 may be made of an impervious material such as a. laminate structure comprising polypropylene threads, ribbons or tapes that are woven together and polymer film made from polypropylene or other suitable polymers. The bag 10 also includes handles 15 for lifting 25 or holding the bag 10 during loading of the bag. As can be seen, the top wall 13 and the side walls 12 have air vent assemblies 16 for venting air from inside the bag 10 while the bag 10 is being filled or 30 while material is settling in the bag 10. In any event, the purpose of the air vent assemblies 16 is to vent air to prevent the formation air bubbles or cavities in the bag 10. 35 Figure 2 illustrates a plan view of the bag 10 shown in Figure 1. Although the air vent assembly 16 may be of arLy size, suitably it covers an area of N.\Melbourne\Cases\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 - 10 approximately 10cm by 10cm square. With reference to Figures 3 and 4, each air vent assembly 16 comprises three vent formations in the form of 5 slits 17 that range from 50mm to 100mm in length and that pierce the otherwise impervious walls 12, 13 of the bag 10. Each air vent assembly also includes a porous material covering the slits 17, suitably in the form of a woven or non-woven fabric 18. The porous material may 10 also be in the form of a loose porous material such as cotton wool. The fabric 18 readily allows air inside the bag 10 to be vented to the atmosphere during filling of the bag 10 or while material in the bag 10 settles. As can be seen in Figure 4, the fabric 18 is attached to 15 inner and outer faces of the walls 12, 13 of the bag 10 by way of stitching 19. In addition, the fabric 18 is substantially impenetrable to dust particles, typically in the size 20 range of 0.05mm to 0.5mm. The fabric 18 therefore serves two purposes, namely preventing copious amounts of dust particles to be released from the bag during filling of the bag. The fabric 18 also prevents any unwanted material from the entering the bag 10 during storage or 25 transportation of a full bag. Furthermore, ideally the fabric 18 also has hydrophobic properties so as to minimize the ingress of the moisture in the bag 10. Figures 5 to 8 illustrate another embodiment of 30 the present invention in the form of a plastic liner 20 suitable for lining the inside of a bulk bag. Liner 20 comprises a base 21, a side walls 22 and top wall which may be present prior to closing and sealing of the bag or alternatively, the top wall may be formed by drawing the 35 side walls 22 together during closing and sealing the bag 20. N.\Melbourne\Casee\Patent\78000-78999\P7BB15.AU\Specie\P78815 3 Sept 08.doc 04/09/08 - 11 Figure 5 illustrates a perspective view of the bag 20 prior to being closed and sealed and Figure 6 illustrates the bag when sealed and with air vent assemblies 23 on the top and side walls of the bag. The 5 bag liner 20 may be used in combination with the bulk bag previously described with reference to Figures 1 to 4, or alternatively, the liner may be used with any other bulk bag available. In any event, the shape of the liner may mimic the shape of a bulk bag with which it is used in 10 combination. Figures 7 and 8 illustrate a detailed view of the air vent assemblies. As can be seen the air vent assemblies 23 comprises vent formations in the form of six 15 circular holes 24 through the wall 22 of the bag and a porous fabric or mesh 25 that covers the holes 24. The porous fabric 25 substantially prevents material loaded in the liner from passing through the holes 24. The air vent assemblies also include a second polymer layer 26 is 20 located over the fabric or mesh 25 and heat or glue bonded about its perimeter so as to form a pouch that contains the porous fabric 25. It is not necessary that a continuous seal 28 be formed about the perimeter of the second polymer layer as shown in Figure 7. Rather is 25 possible that the layer 26 be spot welded at various positions about the porous fabric 25 to prevent leakage of undesired amounts of dust, although it is preferred that the second polymer film is continuously attached to the bag liner 20. 30 Ideally, the second polymer layer and the walls of the bag 20 are in the same material form. In addition, incorporated in either wall of the 35 pouch that forms the air vent assembly is a commercially available valve mechanism 27, suitably a one-way valve mechanism that allows venting of air from inside the pouch N:\Melbourne\Caseo\Patent\78000-78999\P78815.AU\Specis\P78815 3 Sept 08.doc 04/09/08 - 12 and, in turn, venting air inside the bag to the atmosphere. The arrows in Figure 8 indicate the intended direction of movement of the air through the valve. 5 The valve mechanism 27 maybe incorporated into the either wall of the pouch 23 via any suitable technique including gluing or heat welding. However it is preferred that the valve mechanism 28 is fitted into the wall of the pouch that faces outside of the bag, so that the valve 10 helps to prevent the ingress of air and gas, in particular the ingress of moisture, into the bag. Advantages of the various embodiments shown in the Figures and described above are as follows: 15 1) The air vent assemblies are effective at venting air without letting dust from the bag to be released. Hence this is an improvement over simply piercing the bag without any dust control. 20 2) The use of a porous material in conjunction with one way valves as described with reference to the Figures minimizes the likelihood of the contents of the bag clogging up the one-way valve. 25 3) The use of porous material either in conjunction with the existing material used in bulk bag or its inner liner, where the material used in the bulk bag or inner liner has been pierced or perforated as 30 described in some embodiments of this invention, avoids the additional cost and manufacturing complications of adding one-valve into the bulk bags or inner bags. 35 Overall the embodiments described above provide a relatively low cost solution of how to allow the movement of air out of the bulk bag while limiting the movement of N:\Melbourne\Caeee\Patent\78000-78999\P78815.AU\SpeciB\P78815 3 Sept 08.doc 04/09/08 - 13 dust. Those skilled in the art of the present invention will appreciate that many variations and modifications may 5 be made to the embodiments of the invention without departing from the spirit and scope of the present invention. For example, it is possible that air ventilation 10 formation in the wall of the bag may also be provided a one-way valve assembly. If the dust impenetrable layer is present, the valve assembly in the bag wall may in addition to, or instead of, a one-way valve in the dust impenetrable layer. 15 In the claims in relation to this invention and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or 20 variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. N:\Melbourne\Casee\Patent\78000-78999\P78815.AU\Specia\P78815 3 Sept 08.doc 04/09/08

Claims

1. A bag that, for example, may be in the form of a bulk bag or a liner for a bulk bag, the bag comprising a 5 base, side walls extending from the base, and a top wall having an inlet through which material can be loaded into the bulk bag, the walls of the bag being substantially impervious to air and having one or more than one air vent assembly, the or each air vent assembly including 10 i)an air vent formation that allows the passage of air through the wall of the bag; and ii) porous material on or covering the air vent formation which allows the passage of air in and/or out of the bag during filling or emptying of the bag but 15 substantially prevents the passage of material in the bag through the air vent assembly.

2. The bag according to claim 1, wherein the air vent formation in the walls of the bag formed by 20 piercings, perforations or openings in the substantially impervious walls.

3. The bag according to claim 1 or 2, wherein the air vent formation in the walls of the bag are in the form 25 of one or more slits or cutouts in the impervious walls.

4. The bag according to claim 3, wherein each air vent formation comprises between 2 and 6 slits, each of which range from 50 to 100mm in length. 30

5. The bag according to claim 3, wherein each air vent formation comprises between 2 to 6 of the cutouts, each of which range of 1 to 2cm 2 35

6. The bag according to claim 1, wherein the air vent formation is in the form of one or more that one-way air valve assemblies. N:\Melbourne\Cases\Patent\78000-78999\P78815.AU\Specis\P?8815 3 Sept 08.doc 04/09/08 - 15

7. The bag according to any one of claims 1 to 6, wherein the porous material covers a region having the air vent formations that is at least 50cm2 5

8. The bag according to any one of claims 1 to 6, wherein the porous material covers a region having the air vent formations that is approximately 100cm 2

9. The bag according to any one of claims 1 to 8, 10 wherein the porous material is folded at one or more than one position to increase the surface area of the porous material covering the air vent formations.

10. The bag according to any one of claims 1 to 9, 15 wherein the porous material is hydrophilic so as to minimise the ingress of moisture into the bag.

11. The bag according to any one of claims 1 to 10, wherein the bag is in the form of an impervious bulk bag, 20 and the porous material is disposed on either one or a combination of the inner or outer faces of the top and/or side walls.

12. rhe bag according to any one of claims 1 to 11, 25 wherein the porous material comprises a woven or non-woven fabric.

13. The bag according to any one of claims 1 to 12, wherein the porous material is joined to the walls near 30 the edges of the porous material by sewing or stitching.

14. The bag according to any one of claims 1 to 11, wherein the porous material is a mesh having mesh spacings ranging from 0.5mm to 2.0mm 35

15. The bag according to claim 14, wherein the porous material is a mesh having mesh spacings approximately 1 mm N:\Melbourne\Cases\Patent\78000-78999\P7881S.AU\Specia\P78815 3 Sept 08.doc 04/09/08 - 16 in size.

16. The bag according to any one of claims 1 to 15 further including a second polymer layer that is located 5 over the porous material and the layer also has an air vent formation so as to form a pouch that contains the porous material.

17. The bag according to claim 16, wherein the air vent 10 formation of the layer of the pouch that faces outside of the bag is in the form of a one-way valve.

18. The bag according to claim 17, wherein the air vent formation of the layer of the pouch that face inside of 15 the bag walls of the bag are piercings, perforations or openings.

19. The bag according to any of claims 16 to 18, wherein the second polymer layer is joined to the wall of the bag 20 by heat sealing or glueing.

20. The bag according to any one of claims 16 to 19, wherein the second polymer layer has the same material form as the walls of the bag. 25

21. The bag according to any one of claims 1 to 20, wherein the bulk bag has a volume ranging from 0.5 to 2.5 cubic meters. 30

22. The bag according to any one of claims 1 to 21, wherein the bag includes a plug or open and closeable panel in the base that can be moved to help empty the bags. N \Melbourne\Case\Patent\78000-78999\P78815.AU\Specie\P78815 3 Sept 08.doc 04/09/08