AU728068B2 - A flexible bulk bag with liner - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALI[A

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 0

I.

*000 0 *0 0 a Invention Title: A FLEXIBLE BULK BAG WITH LINER The following statement is a full description of this invention, including the best method of performing it known to us: FHP'.Ync WNA 2fl2997fl(W.2 CA97063(X).4 1 A FLEXIBLE BULK BAG WITH LINER FIELD OF THE INVENTION This invention relates to shipping and storage containers and more particularly to large bulk bags of a flexible fabric used for holding, storing and transporting granular or powdered products.

BACKGROUND OF THE INVENTION Fig 1 of the accompanying drawings illustrates a bag 172 reproduced from fig 13 of US Patent 5328268. For the purpose of illustration, lifting straps 8 have been added to the figure. The bag 172 has internal tensioning means including transverse loops of cord 12 which prevent the ooooo 10 rounding out of the bag 172 when filled, so that the bag will tend to maintain a more cubic or *.prismatic shape, in order that a maximum number of bags 172, and thus volume of product, can be packed into an ISO shipping container.

The loops of cord 12 do not pass through the outer wall of the bag 172, because a carrier band or inner member 174 is provided through which the loops of cord 12 pass and against which 15 they lie adjacent so as to perform their shape maintaining duty. The bag 172 has four, substantially unstretchable, loops of cord 12 which are completely inside outer wall of the bag •o*172. The bag 172 has all the loops of cord 12 disposed in the inner member 174 of a flexible fabric material. The inner member 174 is stitched or adhered to the bag at upper and lower peripheries of the inner member 174.

During the filling process, the bag can either be first inflated with air or held in the filling machine by a lifting rig, which supports the empty bag 172 by the lifting straps 8. If held by the lifting rig, the lifting rig is lowered as the bag is filling so as to ensure that the full volume of the bag 172 is filled. However, it has been found that at the last stages of filling a bag 172, the top periphery of the inner member 174 is forced in a downward direction because regions of the CA97063(X).4 2 inner member 174 having product adjacent to them are forced to adopt a path around the loops of cord 12. This forces the upper end of the inner member to move downward, which in turn causes the top ends of the bag 172 to distort inwardly in the directions 173 indicated in Figs 1 and 3. This change in shape of the bag 172 is illustrated in figure 3 which shows a part cross section of the bag 172 in filled or partially filled condition. Whereas in figure 2 is shown a part cross section of the bag 172 in an unfilled condition.

This change in shape of the bag 172 can reduce the maximum fillable volume of the bag by up to SUMMARY OF THE INVENTION o.oooi 10 The invention provides a bulk bag having fabric outer wall and a fabric inner member which surrounds a volume to be filled, said bag being constructed with said outer wall having a first end panel, a filling end opposite to the first end panel; at least two pairs of side panels so that the side panels of each pair are in generally opposed relation and all the side panels extend between said first end panel and said filling end, said outer wall and said side panels each 15 having a first periphery at said first end panel and a second periphery at said filling end; said inner member including at least two pairs of side panels adjacent to said side panels of said outer wall and having a first periphery near to said first end panel and a second periphery near to said filling end, said inner member being attached to said outer wall at at least said first periphery, said bag including at least two closed loops of cord which have portions between said inner member and outer wall and other portions which pass through said inner member into said volume, said bulk bag being characterised by said inner member being able to move, at least at said filling end, relative to said outer wall so that the inner member can adopt a longer path around said cords in those regions of said inner member which have product adjacent to them when said bulk bag is filled, and so that when said bag is being filled, the straight line CA97063(X).4 3 distance between said first and second peripheries of said outer wall is not substantially decreased.

Preferably a second periphery of said inner member near to said filling end is also attached to said outer wall between said first and second peripheries, or at said second periphery of said outer wall, said inner member having a greater length of fabric than the length of fabric of said outer wall its first and second peripheries.

Preferably said greater length of fabric of said inner member is substantially equal to the extra path length that the inner member will adopt around said cords, when the bag contains product.

Preferably said greater length of fabric of said inner member is provided as a gathering of said ooooo 10 inner member.

•go• Preferably said greater length of fabric of said inner member is adapted to extend the length of the inner member in response to outwardly directed force applied to the inner member.

Preferably said greater length of fabric of said inner member is adjacent said filling end so that said inner member can adopt a longer path length when said volume has received a predetermined amount of material.

Preferably said inner member is attached to or includes a return means which can return said oooeo inner member to a condition substantially the same as the condition of the inner member prior to being filled.

Preferably said return means is a retraction means which retracts said greater length of fabric of said inner member as product is emptied from said bag.

Preferably said return means is an expansion means which expands or extends or moves at least a part of said inner member towards said filling end, as product is emptied from said bag.

CA97063(XMX).4 4 Preferably said return means allows said inner member to expand or contract according to the mass of material in said bag.

Preferably said return means is an elastic strap.

Preferably said greater length of fabric of said inner member is held by a frangible member.

Preferably said greater length of fabric of said inner member is approximately 250 mm to 350 mm in length.

Preferably said inner member at its second periphery is attached to said second periphery of said outer wall via bias means which allows said second periphery of said inner member to move away from said second periphery of said outer wall, while said second periphery of said outer :o 10 wall remains substantially stationary.

Preferably said bias means is selected from one of the following: a band of elastic material around said second periphery of said inner member; at least one elastic strip positioned around said second periphery of said inner member.

Preferably said inner member includes connection means connecting its second periphery to a filling spout at said filling end.

Preferably said connection means includes an elastic means to allow for the movement of said inner member relative to said outer wall without changing the shape of said bag.

Preferably said inner member includes an end panel to lie adjacent to said first end panel of said outer wall.

Preferably said filling end includes a filling end panel.

Preferably said filling end panel includes one of the following: flaps which can be tied together when the bag is full of product; a filling spout which can be tied closed; a closable opening.

CA97063(XX0.4 Preferably said inner member is formed from an elastic means or material.

Preferably the elastic tension of any elastic strip, means, material or band mentioned above is between approximately 2 to 10 newtons per centimetre of width to achieve a 100% extension.

Preferably the elastic tension of the previous paragraph is 5 newtons per centimetre width to achieve a 100% extension.

Embodiments having the above features will have an inner member being able to expand or extend or move around the loops of cords which act as reinforcing. Any ability to expand extend or move around the loops of cord will provide an improved bulk bag, because a greater volume will be able to be filled. The greatest improvement will result when the amount of •o.o•i 10 movement allowed or greater length of fabric is substantially equal to the extra path length that 0-.0% .*.the inner member will adopt around said cords, when the bag is substantially full of product. In doing so the volume of the bag remains at its maximum so that the maximum amount of product can be filled into the bag. In a standard sized bag the problems of the prior art can reduce the maximum mass able to be placed in the bag from 950 kg to 850 kg.

BRIEF DESCRIPTION OF THE DRAWINGS 0 The embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig 1 is a reproduction of a bag shown in Fig 13 of US Patent 5328268; Fig 2 illustrates a part cross section of a bag made in accordance with Fig 1 when unfilled; Fig 3 illustrates the bag of Fig 2 in the filled condition; Fig 4 illustrates perspective view of an embodiment of an invention; Fig 5 illustrates a side view of the bag of Fig 4; CA97063X000.4 6 Fig 6A illustrates a part cross section through the bag of Fig 5 at line AA when unfilled; Fig 6B illustrates a part cross section through the bag of Fig 5 at line BB when unfilled; Fig 7 illustrates the part cross section of the bag of Fig 6B when filled; Figs 8 to 11 are perspective views of bag types which could include the features of the invention; Figs 12 to 15 illustrate in schematic view top options for bags which can be used with embodiments of the invention; and Figs 16 to 18 illustrate in schematic view bottom options for bags which can be used with embodiments of the invention.

10 DETAILED DESCRIPTION OF THE EMBODIMENTS Illustrated in Fig 4 is a cubic, or box like, bag 2 having an outer wall 4 and to which is stitched an inner member 6, as will be described in more detail later.

The outer wall 4 is generally manufactured from heavy duty woven polypropylene, polyethylene or other suitable fabric and the inner member 6 is generally manufactured from a S: 15 light duty woven polypropylene, polyethylene or other suitable fabric.

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At each of the top corners of the bag 2 are lifting straps 8 stitched to the outer wall 4. The outer wall 4 includes a base 14 stitched to each of the lower peripheries of four vertical panels The inner member 6 however includes only four side panels 6A which are of substantially the same width as vertical panels The inner member 6 is attached at its lower most periphery 11 to the periphery of base 14 also by stitching, which could be continuous, intermittent or just tack stitched into position. The uppermost periphery 13 of inner member 6 is stitched to the upper periphery of each of the vertical panels 10. This is illustrated in cross section in fig 6A and 6B. In some embodiments CA9706300X1.4 7 the upper most periphery 13 of inner member 6 may be stitched below the upper periphery of vertical panels Positioned internally of the outer wall 4 are a series of five loops of support cords 12 similar to Fig 1. The support cords 12 can be manufactured from 4 mm to 6 mm diameter twisted or plaited rope of polypropylene, polyethylene, or other suitable material. The support cords 12 can also be made from-other materials such as spiral wound cords, flat bands etc. The support cords 12 at regions 16 are parallel to the vertical panels 10 and pass between the inner member 6 and outer wall 4, but do not pass through the outer wall 4. They do however, in the corner ***regions 18, pass through the inner member 6 across the volume 20 to be filled.

ooooo The inner member 6 has a gather, that is a band of gathered material 22 on all four of its sides adjacent the filling end 24. In Fig 4 for clarity of drawing, the gather 22 is only represented on the two closest sides to the reader. However, such a gather 22 is provided in the embodiment on the other two sides as well. The gather 22 adopts a concertina or other gathered shape adjacent o a. the filling end 24. The filling end 24 can alternatively have a series of flaps, or a duffel top in 15 the manner of fig 9, or a cylindrical sheet of fabric, having an opening therethrough, which can be closed off, after filling, by a drawstring, as is illustrated in Figs 8, 10 and 11.

The length of gather 22 makes the total length of the fabric of inner member 6, between the upper most periphery 13 and lower most periphery 11, greater than the length of the fabric of outer wall 4 between the lower most and upper most peripheries 11 and 13 respectively, where inner member 6 is stitched to outer wall 4.

The length of gathered material in the gather 22 is chosen, dependent in part, upon the number of support cords 12 which are present. More support cords 12 require increased length of gather 22. Similarly, the greater the cross sectional size of the cords 12, the greater the gather necessary.

CA97063(XX.4 8 The gathered length of fabric should be substantially equal to the extra path length that the inner member will adopt around the cords 12, when the bag is full of product. However it could be less, so long as the inner member 6 is greater in length than outer wall 4, resulting in the carrying capacity of the bag being greater by comparison to prior art bulk bags.

An extra length of fabric of between 250 mm and 350 mm (greater than the length of outer wall 4) to form the gather 22 will generally suffice assuming up to five to seven cords 12 of 4 to 6 mm diameter, are used.

As illustrated in Figs 4 to 7 a rectangular flat elastic strip 26 can be stitched to the inner member 6 at lower attachment point 28 (figs 6A, 6B and 7) and stitched to the outer wall 4 with inner °o ooI member 6 at upper attachment point 30 (figs 6A, 6B and 7) near the filling end 24. This elastic 0 0.

strip 26 is preferably 300 mm long, 20 mm wide and of an elastic tension of approximately Newtons per centimetre of width to achieve a 100% extension.

The amount of elastic tension suitable for the elastic strip 26 is dependent upon two factors. The suitable minimum elastic tension is determined by the mass of the gathered portion, and the **oO* S 15 mass of fabric and cords 12 below it. The minimum elastic tension must be able to support this mass without letting the gathered portion 22 expand appreciably.

A suitable maximum elastic tension is chosen by the mass per unit volume, (or density) of the product to fill the bag, and the carrying or buckling strength of the vertical panels 10 of the bag.

If the elastic tension is too high the gather 22 fails to effectively release liner fabric into the bag.

For most fabrics utilised, and most products carried, an elastic tension of between 2 Newtons per cm width of the strip and 10 Newtons per cm width of the strip to achieve a 100% elongation is suitable.

Referring now to Figs 6A, 6B and 7, the gathered portion 22 is held between the two points and 28 by the elastic strip 26 when unextended. As the bag 2 is filled, the elastic strips 26 will CA9706300(X.4 9 progressively expand to its maximum as is illustrated in Fig 7. This will let out, as required, sufficient inner member 6 from the gather 22 to compensate for additional path length. This prevents the four vertical panels 10 at the filling end from collapsing as in Fig 3.

When the bag is emptied by means of an emptying spout 32 as illustrated in Figs 8 to 11, the elastic strip 26 will progressively contract as product is removed. When the bag is empty the elastic strap 26 will be fully contracted from the position illustrated in Fig 7 to that illustrated in Fig 6.

The invention can be applied widely to fabric bulk bags such as those illustrated in Figs 8 to 11.

In Fig 8 shows a bulk bag having a safe working load of approximately 1500 kg with a filling 10 spout 24A and an emptying spout 32 which can be suitably tied off by ties 34 and 36 respectively.

Illustrated in Fig 9 shows a bulk bag having a safe working load of 500 kg in which the filling end 24 includes a large flap type spout for rapid fill of the bag, which is also closed off by a tie 34.

Illustrated in Fig 10 shows the bag of Fig 10 also having an emptying formation 32.

o In Fig 11 shows a 1000 kg safe working load bag having only a filling spout 24A and no emptying spout. This embodiment is not reusable, because the base 14 must be cut to empty the contents. The previously described embodiment of the invention can be utilised with this bag, but as the bag is not reusable, the next embodiment is most preferably used.

If desired, the embodiment of Figs 4 to 7 can be modified so that the elastic straps 26 are replaced by means of a frangible cords 27 (see Fig 5 inset), which when the bag is partially full with product, break under the strain of the forces which would tend to stretch the frangible cord 27 between points 28 and 30. Upon breaking of the frangible cord 27, the gather 22 can then CA97063(XX).4 expand or ungather as shown in Fig 7. However, when the product is emptied from the bag, the expanded gathered portion does not re-gather, which is not of a concern in a single use duty.

The frangible cords 27 can be externally or internally stitched to the inner member, as desired.

The same can be said for the elastic straps 26 which will work equally well in the internal volume 20 as they will between the inner member 6 and outer wall 4.

In other embodiments of the invention, the bag 2 can be manufactured so that the inner member 6 is not directly stitched to the outer wall 4 at the filling end 24, as it is in fig 4. This is illustrated in fig 15 where either a band of elastic 26 or at least one strip of elastic 26 is attached between the filling end periphery of the inner member 6 and the filling end periphery of the olooo outer wall 4. This elastic strip or band 26 will allow the inner member 6 and its upper periphery, to move downward into the bag, as the bag is filled. In this embodiment it is preferable that a loop of cord 12 is connected to the elastic strip or band so that it will provide a cord in the upper 00 levels of the bag when full.

If strips of elastic 26 are used in the embodiment of the previous paragraph, this could allow 15 product to fall between the free end 27 of the inner member and the outer wall. However if such .product should fall in this location, the amount is expected to be a relatively small. This is "expected because the inner member is stitched or tacked to the base of the bag so that as the bag is being filled, the pressure of the inner member 6 against the outer wall 4, at least up to the cord nearest to the filling end 24, is expected to be sufficient to close off gaps between the inner member 6 and outer wall 4 to prevent any substantial quantity of material falling between the inner member 6 and outer wall 4.

In another embodiment illustrated in fig 12 the inner member 6 includes a filling end 24B and a spout 24C which sits adjacent to and concentrically with the filling spout 24A of the bag. This filling end can include an elastic means 26 (of fig 15) or an elastic means 26 and a gather 22 of CA97063000.4 11 fig 4, which will allow the inner member to adopt the greater path length as the bag is filled, and then to suitably retract the inner member as the bag is emptied.

Illustrated in fig 13 is a bag having a flap top which includes a gather 22, and can also include an elastic strap 26.

In figure 14 is a bag which has the filling end wall 24D constructed as part of the inner member, which is attached to the outer wall 4 in the same manner as in fig 4 with a gather 22.

Illustrated in fig 16 is a part cross section of a bag showing the inner member 6 including a base portion.

Oe oFigure 17 illustrates a bag similar to that of figure 16, except that the inner member and outer wall together have formed in them an emptying spout similar to figs 8 to *see Figure 18 illustrates a bag having a base which can be used to fully empty the bag by a full bottom opening, which is tied off by ties 34, before filling.

SIn another embodiment of the invention the inner member 6 is constructed from an elastic type material which will allow expansion of the material to accommodate the greater path length S: 15 required when the bag is filled.

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The foregoing describes some embodiments of the present invention and modifications as go would be obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.

Dated this 12th day of March 1998 Southcorp Australia Pty Ltd (ACN 004 213 665) by its attorneys Freehills Patent Attorneys

Claims (23)

1. A bulk bag having fabric outer wall and a fabric inner member which surrounds a volume to be filled, said bag being constructed with said outer wall having a first end panel, a filling end opposite to the first end panel; at least two pairs of side panels so that the side panels of each pair are in generally opposed relation and all the side panels extend between said first end panel and said filling end, said outer wall and said side panels each having a first periphery at said first end panel and a second periphery at said filling end; said inner member including at least two pairs of side panels adjacent to said side panels of said outer wall and having a first S° 10 periphery near to said first end panel and a second periphery near to said filling end, said inner member being attached to said outer wall at at least said first periphery, said bag including at S"least two closed loops of cord which have portions between said inner member and outer wall Sand other portions which pass through said inner member into said volume, said bulk bag being characterised by said inner member being able to move, at least at said filling end, relative to said outer wall so that the inner member can adopt a longer path around said cords in those 0 regions of said inner member which have product adjacent to them when said bulk bag is filled, and so that when said bag is being filled, the straight line distance between said first and second peripheries of said outer wall is not substantially decreased.

2. A bulk bag as claimed in claim 1, wherein said inner member is also attached, at a second periphery near to said filling end, to said outer wall between said first and second peripheries, or to said second periphery of said outer wall, said inner member having a greater length of fabric than the length of fabric of said outer wall between its first and second peripheries. CA97063(XX).4 13

3. A bulk bag as claimed in claim 2 wherein said greater length of fabric of said inner member is substantially equal to the extra path length that the inner member will adopt around said cords, when the bag contains product.

4. A bulk bag as claimed in claim 2 or 3 wherein said greater length of fabric of said inner member is provided as a gathering of said inner member.

A bulk bag as claimed in any one of claims 2 to 4, wherein said greater length of fabric of said inner member is adapted to extend the length of the inner linear in response to outwardly directed force applied to the inner member.

6. A bulk bag as claimed in any one of claims 2 to 5, wherein said greater length of fabric 10 of said inner member is provided at said filling end so that said inner member can adopt a longer path length when said volume has received a predetermined amount of material.

7. A bulk bag as claimed in any one of claims 1 to 6, wherein said inner member is S attached to or includes a return means which can return said inner member to a condition substantially the same as the condition of the inner member prior to being filled. *.i 15

8. A bulk bag as claimed in claim 7, wherein said return means is a retraction means which retracts said greater length of fabric of said inner member as product is emptied from said bag.

9. A bulk bag as claimed in claim 7, wherein said return means is an expansion means which expands or extends or moves at least a part of said inner member towards said filling end, as product is emptied from said bag.

10. A bulk bag as claimed in claim 7, 8 or 9, wherein said return means allows said inner member to expand or contract according to the mass of material in said bag.

11. A bulk bag as claimed in any one of claims 7 to 10, wherein said return means is an elastic strap. CA97063(XX).4 14

12. A bulk bag as claimed in an one of claims 1 to 5, wherein said greater length of fabric of said inner member is held by a frangible member.

13. A bulk bag as claimed in any one of claims 2 to 12, wherein said greater length of fabric of said inner member is approximately 250 mm to 350 mm in length.

14. A bulk bag as claimed in claim 1 wherein said inner member at its second periphery is connected to said second periphery of said outer wall via bias means which allows said second periphery of said inner member to move away from said second periphery of said outer wall, while said second periphery of said outer wall remains substantially stationary.

15. A bulk bag as claimed in claim 14 wherein said bias means is selected from one of the 10 following: a band of elastic material around said second periphery of said inner member; one or more elastic strips positioned around said second periphery of said inner member.

16. A bulk bag as claimed in claim 1 wherein said inner member includes connection means connecting its second periphery to a filling spout at said filling end.

17. A bulk bag as claimed in claim 16 wherein said connection means includes an elastic 15 means to allow for the movement of said inner member relative to said outer wall without changing the shape of said bag.

18. A bulk bag as claimed in any one of claims 1 to 17, wherein said inner member includes an end panel to lie adjacent to said first end panel of said outer wall.

19. A bulk bag as claimed in any one of claims 1 to 18, wherein said filling end includes a filling end panel. A bulk bag as claimed in any one of claims 1 to 15 wherein said filling end panel includes one of the following: flaps which can be tied together when the bag is full of product; a filling spout which can be tied closed; a closable opening.

CA97063(XX).4

21. A bulk bag as claimed in claim 1 wherein said inner member is formed from an elastic means or material.

22. A bulk bag as claimed in any one of claims 11,15,17 or 21, wherein the elastic tension of the elastic strip, means, material or band is between approximately 2 to 10 newtons per centimetre of width to achieve a 100% extension.

23. A bulk bag as claimed in claim 22 wherein the elastic tension is 5 newtons per centimetre width to achieve a 100% extension.