NZ286110A - Packaging of or pouch for powdered material such as milk powder; escape of air is via labyrinth at closed end of pouch - Google Patents

Description

Patents Form # 5 28 6110 NEW ZEALAND f z? FEni997 Patents Act 1953 j ^ . ; ; oeiv jD COMPLETE SPECIFICATION AFTER PROVISIONAL # : 286110 DATED : 1 March 1996 TITLE : Packaging of Particulate Material We, HA H&Lmes & Coy Ltd Address: 346-350 Te Ngae Road, Lynmore, Rotorua, New Zealand Nationality: New Zealand do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: PF05.JWP FEE CODE 1050 28 6 1 FIELD This invention relates to the packaging of particulate material and has particular application to fine powders such as milk powder typically packed into 25kg packs comprising a multi-wall paper sack having a polymer liner.

BACKGROUND Milk powder is typically packed into 25kg sacks, the sacks typically comprising a multi-wall paper sack having a polymer liner. In some cases it may be packed into a polymer pouch or sack, or one which is used as the liner of a bag in box container systems. Whatever system is used, the entrainment of air during the filling 10 operation creates difficulties in obtaining a stable package.

For example, milk powder is a "fluffy" aerated powder made up of fine particles typically within the range of 12 microns to 200 microns and as such during the filling operation a considerable amount of air is entrained with the powder particles. For example a 25kg pack would be made up into a polymer pouch of approximately 15 0.8-1.2 metres long and approximately 500mm wide. Previously such bags would have a heat seal at the bottom, the bag would be filled to capacity and then heat sealed across the top so that there was no or minimal head space. Such bags would then be packed onto pallets, strapped up and transported.

Problems arise during transport, because of the fluffy nature of the milk powder 20 (and the amount of air entrained within the powder) so that even though the bags may be strapped onto the pallets, they would move and slide off or fall off the pallets so that during transport the driver may have to stop and reposition the sacks a number of time during a trip, or risk losing his load.

OBJECT It is an object of this invention to provide an improved system of packaging particulate material and in particular to provide improved packaging for use with particulate material, or one which will at least provide the public with a useful choice.

INrELLECTm^PROPERTY' OFFICE] of n.z. 9451ZCLS.698/JP/cb 2 3 '' 'M |993 RECEh. 286 1 STATEMENT OF INVENTION In one aspect, the invention provides a method of packaging particulate material in which particulate material is to be contained in a pouch having an open end and a closed end, the pouch also having a labyrinth seal at or adjacent the closed end of 5 the pouch, the pouch being filled to a desired capacity and then being sealed at or adjacent the open end thereof, so that any entrapped air can escape via the labyrinth seal with minimal, or no, escape of the particulate material.

Preferably the open end of said pouch is adapted to be heat sealed.

Preferably the said labyrinth seal is formed by a first seal having one or more small 10 apertures therein and a second adjacent seal extending across said pouch, having one or more apertures therein offset from the position of the apertures in said first seal.

Preferably said pouch is formed from a plastic or other flexible material, or combination of plastic or flexible material capable of being heat sealed by direct 15 action/application of conducted heat or electronically induced heat sealing such as ultrasonics.

Preferably said first and second seals are formed by heat sealing, with the apertures being formed by unsealed portions of the material of the pouch.

Preferably said first heat seal has larger, or more, apertures than the size or number 20 of apertures in said second seal.

Preferably said seals are be placed at either ends of a tube of heat sealable material.

Preferably the thickness of said tube forming the packaging is in the range from 40-200 microns.

Preferably said tube forming the packaging is formed continuously in 25 circumference. 9451ZCLS.698/JP/cb 2 o j'jr: 1998 1 received intellectual property office of n.z. office"] J Preferably a single sheet of material is used to form said packaging and is wound into a tube and is longitudinally seamed by heat sealing or using a suitable adhesive.

In another aspect, the invention provides a method of packaging particulate material 5 in which said particulate material is to be contained in a pouch and said pouch is the liner of a multi-ply sack.

Preferably the open end of said pouch is heat sealed after filling of said pouch is In yet another aspect the invention provides a pouch for use in packaging particulate 10 material, said pouch having an open end and a closed end, the pouch having a labyrinth seal at or adjacent the closed end of the pouch, the labyrinth seal being adapted to assist in the escape of entrapped air whilst the same time minimising, or preventing, escape of any particulate material.

Preferably the open end of said pouch is adapted to be heat sealed.

Preferably said labyrinth seal is formed by a first seal having one or more small apertures therein and a second adjacent seal extending across the pouch, having one or more apertures therein offset from the position of the apertures in said first seal.

Preferably said pouch is formed from a plastic or other flexible material, or combination of plastic or flexible material capable of being heat sealed by direct 20 action/application of conducted heat or electronically induced heat sealing such as ultrasonics.

Preferably also said first and second seals are formed by heat sealing, with the apertures being formed by unsealed portions of the material of the pouch.

Preferably said first heat seal has larger, or more, apertures than the size or number 25 of apertures in said second seal.

Preferably said seals are be placed at either ends of a tube of heat sealable material. complete. 945 i ZCLS .698/J P/cb intellectual property office of n.z. ?: j',"! 1998 L. received 286110 Preferably the thickness of said tube forming the pouch is in the range from 40-200 microns.

Preferably said tube forming the pouch is formed continuously in circumference.

Preferably also a single sheet of material used to form the pouch is wound into a tube and is longitudinally seamed by heat sealing or using a suitable adhesive.

Preferably said pouch is the liner of a multi-ply sack. Such multi-ply sacks typically have two or more layers of Kraft paper on the outside and a single wall polymer pouch as the liner for containing the particulate material.

The outer bag construction material can be plastic, spunbonded, or other breathable naterial instead of the present Kraft paper.

The bottom of this sealed pouch is not necessarily at the bottom of the sack as it is sometimes preferable to print the sacks upside down, ie this labyrinth seal is located at the top of the bag after filing.

In another aspect the invention provides a filled pouch comprising a pouch and particulate material.

Preferably the open end of said pouch is heat sealed after filling is complete.

It will be appreciated that the invention can be used with plastic pouches of any size or shape, whether forming part of the multi-ply bag or sack, forming the liner of other packaging systems, or as an all polymer pouch bag of single or multiple plies.

DRAWINGS These and other aspects of the invention, which are to be considered in all these novel aspects, become apparent from the following description, which is given by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a preferred seal configuration for a polymer pouch. 9451ZCLS.698/J P/cb INTELLECTUAL PROPERTY OFFiCE of n.z.

Or- jun 1s98 RECEIVED -6 2861 1 Figure 2 illustrates the closed end of a bag of the preferred embodiment of the invention.

PREFERRED EMBODIMENT Figure 1 illustrates a polymer pouch used as the liner of a multi-ply paper bag or 5 sack. In this example the sack may be from 0.8 metre to 1.2 metres long and from 505mm to 580mm wide. Such a sack is designed to contain approximately 20 - 30 kg of milk powder at a density of about 0.3 to 05g/cc. These dimensions are given by way of example only to enable the reader to appreciate the relative dimensions of the seals and apertures and the problem in packaging 25kg of a fluffy powder 10 such as milk powder into a multi-ply paper sack having a polymer pouch as the liner for thai sack. As explained in the background, such packages are relatively floppy and in the past have been difficult to transport because of the amount of air entrained within each sack.

During manufacture of the polymer pouch it is preferred that the base of the pouch 15 has a labyrinth seal designed to enable the escape of any entrained air whilst at the same time minimising or preventing the escape of any powder contained within the main region of the pouch.

The pouch 10 has a first seal 11 extending substantially across the width of the bag, adjacent the base thereof and this seal is preferably formed by heat sealing the 20 layers of the bag together, whilst leaving one or more regions of the bag unsealed to provide one or more apertures 12, 13. Preferably these apertures 12, 13 are positioned adjacent the edges of the first seal 11 and are preferably of larger size than any aperture or apertures contained in a second or subsequent seal.

A labyrinth seal is achieved by providing a second or subsequent seal 15 adjacent to 25 but slightly spaced apart from the first seal 11. It is also preferred that this is formed by heat sealing the layers of the polymer pouch together. Preferably this seal has a single aperture 16 positioned therein and offset from the position of the apertures 12,13 in the first seal.

In some cases it may be desirable to provide a third or fourth seal, with offset 30 apertures to provide a further labyrinth, in order to prevent the e^e^ge^ of n.z. 9451ZCLS ,698/JP/cb JUN 1SS8 RECEIVED 28 61 10 particulate material. In the case of milk powder, of size in the range of 12 microns to 200 microns, we believe that two heat seals, with the offset apertures is sufficient to enable escape of air, whilst minimising or preventing escape of the particulate material.

Preferably the apertures 12,13 in the first seal 11 are of larger size than the aperture or apertures 16 positioned in the second seal 15.

For example, in the preferred embodiment, namely a bag designed to accommodate 20 - 30 kg of milk powder, the first seal 11 is approximately 5mm deep and extends substantially the full width of the 505mm bag, leaving two apertures 12,13 each of 10 2mm wide enabling air to escape from the main cavity 20 of the pouch through the apertures 12,13 to an unsealed region 21 between the seals 11,15. This region 21 is preferably of comparable width to the width of the seals 11,15, ie. approximately 5mm deep. Seal 15 is also 5mm deep and extends across substantially the entire width of the pouch, except for the unsealed portion 16, which in this case is 15 approximately 1mm wide, providing a smaller outlet for the air than is provided by the two apertures 12,13.

In each case it is preferred that the combined aperture size in the first seal, ie. the number and width of the apertures is greater than the combined aperture size (ie. number and width of apertures) in the second seal.

The apertures for a 25kg milk powder sack may vary from 0.5mm to 5mm wide, and will preferably in the case of the apertures in the first seal there are preferably two or more apertures of from l-3mm wide and more preferably each is about 2mm wide.

In the case of the aperture or apertures in the second seal it is preferred that each 25 such aperture is of smaUer width than the apertures in the first seal, such an aperture 16 may be from 0.5mm to 15mm and more preferably is about 1mm wide.

Although not illustrated, the heat seals 11 and 15 may be of different depth, for example the labyrinth seal could be achieved by increasing the depth of the seal 15, so that the aperture 16 is longer, and narrower than any aperture passing through 30 seal 11. 9451ZCLS.698/J P/eb RECEIVED Although this preferred embodiment has been described with reference to heat seals, it >vould be appreciated that the material of the bag could be sealed together in other suitable ways (depending upon the material used for the pouch) examples include friction or ultra-sonic welding, by suitable adhesives, or by other means in 5 order to provide a labyrinth seal for the escape of air.

The depth of the seals 11, 15 and the unsealed space 21 between them may be determined by the size and spacing of the heat sealing bars, used in the manufacture of these pouches.

Preferably the seals 11 and 15 are formed in the pouch before it is combined with 10 the Kraft paper to form the multi-ply paper sack or bag. Typically such bags have two or three layers of Kraft paper protecting the inner polymer pouch.

A multi-ply paper sack 30 as described in the paragraph above is shown in figure 2. The sack 30 has a inner plastics pouch 10 and an outer multi ply paper bag 31. The seals 11 and 15 (not shown in figure 2) are adjacent to the bottom of the outer bag 15 31. The bottom of the outer bag 31 is covered by a porous patch 32. This allows the air which has escaped through the labyrinth seal of the inner plastics pouch 10 to escape through the outer bag 31. The porous patch 32 is not sealed completely around its edge so as to provide vents 33 to further facilitate the escape of air.

In use, the bags are presented to a fill head 26 and filled with milk powder or other particulate material, to the desired height, whilst at the same time the bags may be vibrated, or shaken, by suitable means. Preferably the bags are vibrated by rubber mallets to assist in settling the powder within the pouch of the multi-ply sack.

When the bag is filled to the required height or weight, a third seal 25 is formed at 25 or adjacent the top of the pouch and this is preferably a heat seal, so that the powder is fully sealed within the cavity 20 defined between the heat seal 25 and the heat seal 11 of the pouch. The outer layers of the multi-ply sack may also be folded or sealed in any convenient way. 110 METHOD 9451 ZCLS.698/JP/eb [7NTELLECTUAL*PR0PcfiTY OFFlld OF N.Z.

JUN 19S8 11" C E i V E D r# -9. 2861 ADVANTAGES By allowing entrained air to escape from the bag partly during the filling operation and partly during settling as the bags are stacked for storage, or stacked onto pallets for transport, it is possible to provide a more secure load of particulate material stored within multi-ply sacks. The air will escape under a constant pallet load through the semi-porous paper bottom patch and other construction vents. It is believed that this will improve the density of the sacks packed onto a pallet and will also improve their stability for transport purposes.

VARIATIONS As explained above the labyrinth seal is preferably formed from two heat seals 11, 15 but there may be three or more such seals, the seals may be of different dimensions and the number and spacing of the apertures may differ significantly from that illustrated, the aim being to provide a labyrinth seal which allows the escape of the trapped air whilst at the same time minimising or preventing the 15 escape of any particulate material contained within the bag. It will be appreciated that the number and position and size of apertures may be varied depending upon the nature of the particulate material to be contained within the bag and/or the degree of entrapped requiring removal.

Although it is preferred that the labyrinth seal is provided at the base of the bag it 20 will be appreciated that it may be positioned elsewhere in the bag - eg at the side or at the top of the bag (although that may be more costly to manufacture or may require the customer to form a special seal after packing - which is less desirable).

Finally, various other alterations or modifications may be made to the foregoing without departing from the spirit or scope of this invention. 945 lZCLS.698/JP/cb I INTLLLEClUAL PRGPcnTY OFFiL't OF N.Z. 2: JUN 13^3 i | \ RECEIVED J 286110

Claims (27)

WHAT WE CLAIM IS:

1. A method of packaging particulate material in which particulate material is to be contained in a pouch having an open end and a closed end, the pouch also having a labyrinth seal at or adjacent the closed end of the pouch, the pouch 5 being filled to a desired capacity and then being sealed at or adjacent the open end thereof, so that any entrapped air can escape via the labyrinth seal with minimal, or no, escape of the particulate material.

2. A method of packaging particulate material as claimed in claim 1 wherein the open end is adapted to be heat sealed. 10

3. A method of packaging particulate material as claimed in any one of claims 1 to 3 wherein the labyrinth seal is fcmed by a first seal having one or more small apertures therein and a second adjacent seal extending across the pouch, having one or more apertures therein offset from the position of the apertures in the first seal. 15

4. A method of packaging particulate material as claimed in any preceding claim wherein the pouch is formed from a plastic or other flexible material, or combination of plastic or flexible material capable of being heat sealed by direct action/application of conducted heat or electronically induced heat sealing such as ultrasonics. 20

5. A method of packaging particulate material as claimed in any preceding claim wherein the first and second seals are formed by heat sealing, with the apertures being formed by unsealed portions of the material of the pouch.

6. A method of packaging particulate material as claimed in any preceding claim wherein the first heat seal has larger, or more, apertures than the size or 25 number of apertures in the second seal.

7. A method of packaging particulate material as claimed in any preceding claim wherein the seals are be placed at either ends of a tube of heat sealable material. 9451ZCLS .698/J P/eb INTELLECTUAL PROPERTY OFFiCE1 OF N.Z. 23 jun i:::3 RECEIVED -11 286 1

8. A method of packaging particulate material as claimed in any preceding claim wherein the thickness of the tube forming the packaging is in the range from 40-200 microns.

9. A method of packaging particulate material as claimed in any preceding claim 5 wherein the tube forming the packaging is formed continuously in circumfertnce.

10. A method of packaging particulate material as claimed in any one of claims 1 to 7 wherein a single sheet of material used to form the packaging is wound into a tube and is longitudinally seamed by heat sealing or using a suitable 10 adhesive.

11. A method of packaging particulate material as claimed in any one of the preceding claims wherein the pouch is the liner of a multi-ply sack.

12. A method of packaging particulate material as claimed in any of the preceding claims whereon the open end of the pouch is heat sealed after filling of the 15 pouch is complete.

13. A pouch for use in packaging particulate material, said pouch having an open end and a closed end, the pouch having a labyrinth seal at or adjacent the closed end of the pouch, the labyrinth seal being adapted to assist in the escape of entrapped air whilst the same time minimising, or preventing, 20 escape of any particulate material.

14. A pouch as claimed in claim 13 wherein the open end is adapted to be heat sealed.

15. A pouch for use in packaging particulate material as claimed in claims 13 to 14 wherein the labyrinth seal is formed by a first seal having one or more 25 small apertures therein and a second adjacent seal extending across the pouch, having one or more apertures therein offset from the position of the apertures in the first seal. I N'raiECTUAL'l'RO PiiHTY^Fild OF N.Z. 94 51ZCLS .698/J P/cb j 2 3 jun 1s38 RECEIVED -12 286 1 1

16. A pouch for use in packaging particulate material as claimed in claims 13 to 15 wherein the pouch is formed from a plastic or other flexible material, or combination of plastic or flexible material capable of being heat sealed by direct action/application of conducted heat or electronically induced heat 5 sealing such as ultrasonics.

17. A pouch for use in packaging particulate material as claimed in any one of claims 15 to 16 wherein the first and second seals are formed by heat sealing, with the apertures being formed by unsealed portions of the material of the pouch. 10

18. A pouch for use in packaging particulate material as claimed in any one of claims 15 to 17 wherein the first heat seal has larger, or more, apertures than the size or number of apertures in the second seal.

19. A pouch for use in packaging particulate material as claimed in any one of claims 15 to 18 wherein the seals are be placed at either ends of a tube of heat 15 sealable material.

20. A pouch for use in packaging particulate material as claimed in any one of claims 13 to 19 wherein the thickness of the tube forming the pouch is in the range from 40-200 microns.

21. A pouch for use in packaging particulate material as claimed in any one of 20 claims 13 to 20 wherein the tube forming the pouch is formed continuously in circumference.

22. A pouch for use in packaging particulate material as claimed in any one of claims 13 to 21 wherein a single sheet of material used to form the pouch is wound into a tube and is longitudinally seamed by heat sealing or using a 25 suitable adhesive.

23. A pouch for use in packaging particulate material as claimed in any one of claims 13 to 22 wherein the pouch is the liner of a multi-ply sack. 9451ZCLS ,698/JP 'eb INTELLECTUAL PROPERTY OFFiCE OF N.Z. 26 JUN 13:3 RECEIVED -13- 286 1 10

24. A filled pouch comprising a pouch as claimed in any one of claims 13 to 23 and particulate material.

25. A filled pouch as claimed in claim 24 wherein an open end of the pouch is heat sealed after filling is complete. 5

26. A method of packaging particulate material substantially as herein described and with reference to the accompanying drawings.

27. A pouch for use in packaging particulate material as substantially herein described and with reference to the accompanying drawings. 10 HA. HOLMES & COY LTD by their Attorneys JAMES W. PIPER & CO 9451 ZCLS.698/JP/eb intellectual property off,it of n.z. 2: jun is;s received