WO2007138331A1

WO2007138331A1 - Bag filled with swelling material upon contact with water

Info

Publication number: WO2007138331A1
Application number: PCT/GB2007/002028
Authority: WO
Inventors: Frances Carney Cleeton
Original assignee: Analox Environmental Technology Limited
Priority date: 2006-06-01
Filing date: 2007-06-01
Publication date: 2007-12-06
Also published as: GB2438613B; GB0610822D0; EP2032766A1; GB2438613A

Abstract

A filled bag (101) for providing part of a temporary barrier to water. The bag comprises a water permeable envelope (502) and a granular material (401) located within the envelope. The envelope is formed of a first face (205) having first edges (203), and a second face (206) having second edges (204) directly connected to the first edges of the first face. The granular material is of a type which absorbs water and swells up. The bag also has a connecting means (501) for connecting the first face (205) of the envelope (502) to the second face (206) of the envelope (502), such that the granular material (401) surrounds the connecting means (501). Consequently, when the bag (101) is immersed in water and the granular material (501) swells to fill the envelope (502), the connecting means (501) holds the opposing parts of the faces together to provide the envelope (502) with a shape that is stable on a flat surface.

Description

BAG FILLED WITH SWELLING MATERIAL UPON CONTACT WITH WATER

Background of the Invention The present invention relates to a filled bag for providing part of a temporary barrier to water, and a method of manufacturing a filled bag.

For many years it has been known to construct temporary barriers to water from sandbags. The sand is both heavy and bulky, and therefore there are problems with storage and transportation to locations where the water barrier is required.

In recent years an alternative filled bag has been produced which contains a super absorbent polymer, or S.A.P. When dry, the S.A.P. is light and of relatively low volume, and therefore storage and transportation problems are reduced. When immersed in water, the S.A.P. swells up to fill the bag, and thus the bag becomes a useful size when building a barrier. A problem with such S.A.P. filled bags is that the walls of the bag tend to balloon outward under pressure from the expanding S.A.P., the bag takes on a rounded shape and consequently becomes an unstable shape for building. I.e. as the bag is rounded it tends to roll.

Brief Summary of the Invention

According to a first aspect of the present invention, there is provided a filled bag for providing part of a temporary barrier to water, comprising: a water permeable envelope formed of a first face having first edges, and a second face having second edges directly connected to said first edges of said first face; a granular material located within said envelope, said material being of a type which absorbs water and swells up; and connecting means connecting opposing parts of said first face and said second face of said envelope, such that said granular material surrounds said connecting means, whereby when said bag is immersed in water and said granular material swells to fill said envelope, said connecting means holds said opposing parts of said faces together to provide said envelope with a shape that is stable on a flat surface.

According to a second aspect of the present invention, there is provided a method of manufacturing a filled bag for providing part of a barrier to water, comprising the steps of: forming an open-ended envelope from a sheet of water permeable fabric by connecting edges of a first face to edges of a second face; obtaining a granular material which absorbs water and swells up; putting said granular material within said envelope; closing the open end of said envelope; and connecting said first face of said envelope to said second face of said envelope by a connecting means, such that said granular material surrounds said connecting means to provide said envelope with a shape that is stable on a flat surface when said granular material is swollen by immersion in water. According to a third aspect of the present invention, there is provided filled bag for providing part of a temporary barrier to water, comprising: a water permeable envelope; a granular material located within said envelope, said material being of a type which absorbs water and swells up; and connecting means for connecting opposing parts of said envelope, such that said granular material surrounds said connecting means, whereby when said bag is immersed in water and said granular material swells to fill said envelope, said connecting means holds said opposing parts of said envelope together to provide said envelope with a shape that is stable on a flat surface, wherein said envelope has a wall comprising an outer layer and an inner layer attached to said outer layer to maintain the position of the inner layer within the outer layer, and said granular material is located inside said inner layer.

Brief Description of the Several Views of the Drawings Figure 1 shows a filled bag 101, along with a pile of other similar bags 102;

Figure 2 shows a cotton sheet 201 on top of a hessian sheet 202, being folded in half to form a double-walled envelope envelope;

Figure 3 shows the folded sheets 201 and 202 sewn together, along their short edges 203, 204 and another edge 301 to form an open-ended envelope 302;

Figure 4 shows water absorbent material 401 being poured into the open-ended envelope 302 through an opening 305;

Figure 5 shows the bag 101 , after completion by strong stitches 501 in the centre of the envelope;

Figures 6 and 7 show respectively a perspective view and a cross- sectional view of the bag 101 after immersion in water;

Figure 8 shows the bag 101 in cross-section resting in a stable manner on another similar bag 801; Figure 9 shows an alternative filled bag 901 ; and

Figure 10 shows partly assembled component parts of the bag 901.

Written Description of the Best Mode for Carrying out the Invention Figure 1 A filled bag 101 is shown in Figure 1 , along with a pile of other similar bags 102. The filled bag 101 is suitable for use with other similar bags to build a temporary wall for use as a barrier to water.

The bags 101 , 102 have a water permeable envelope containing a granular material of a type which absorbs water and swells up. The bags 101 , 102 are shown in Figure 1 in their dry state, and consequently the granular material takes up a comparatively small volume. Thus, the bags 101 , 102 are easily stacked and take up a relatively small amount of storage space when compared with sand used to fill traditional sandbags. Figures 2, 34 and 5

A method of manufacturing the filled bag 101 is illustrated by Figures 2 to 5.

The bag 101 has a double wall comprising tough coarse woven fabric outer wall and an inner wall of a finer woven material. In the present case, the outer wall is made from hessian, while the inner wall is made from cotton.

Thus, the first step in making the bag 101 is to cut out a rectangular sheet of hessian and a rectangular sheet of cotton material of the same size. In the present example, the sheets are 60 centimetres by 74 centimetres. The cotton sheet 201 is then placed directly on top of the hessian sheet 202, such that their corresponding edges are aligned. The two sheets are then folded in half, as shown in Figure 2, to form a first face 205 and a second face 206. Thus, the short edges 203 of the sheets 201 and 202 are positioned alongside the opposing short edges 204. The folded sheets 201 and 202 are then sewn together, using jute yam, along their short edges 203, 204 and another edge 301 to form an open-ended envelope 302, as shown in Figure 3. Thus, open-ended envelope 302 is rectangular and has two sides formed from edges connected by stitching 303, a third side formed by a fold 304 in the sheets and a fourth side providing, an opening 305.

It may be noted that the edges of the two fabric sheets are sewn together using an overlook stitch to prevent either of them from fraying.

Water absorbent material 401 is then poured into the open-ended envelope 302 through the opening 305 as shown in Figure 4. The water absorbent material is a super absorbent polymer (SAP.), which is a free- flowing granular material having a similar appearance to fine white sand. An example of the super absorbent polymer which may be used is Degussa/Stockhausen Favor-Pak 230. For the size of bag in the present example, a 130-gram quantity of super absorbent polymer is used. With the super absorbent polymer enclosed within the envelope, the opening 305 is sewn up to produce a closed envelope 502. Thus, the polymer is contained within the inner wall of the double walled envelope.

It may be noted that while the coarser hessian outer wall provides the bag with a hard wearing outer surface, the finer cotton inner wall has a sufficiently fine weave to prevent the polymer grains from escaping. The bag 101 is then completed, as shown in Figure 5, by making a number of stitches 501 in the centre of the envelope, i.e. 30 centimetres from the ends and 18.5 centimetres from the sides of the envelope, joining the back and front faces of the envelope together. The stitches 501 are made using a jute yarn, of the type used to sew the edges of the envelope together. In the present embodiment the stitches are arranged in a block approximately 20 millimetres in length and 5 millimetres wide. However, they may be arranged in blocks of other formats, such as 10 millimetres by 10 millimetres, but to provide sufficient strength, the block has an area of approximately 1 cm² (1 square centimetre) or more. In an alternative embodiment, the stitches 501 are replaced by an alternative means of connecting the opposing faces of the envelope together. For example, in one embodiment the front and back of the bag are tied together in the middle of the envelope. In this case, the stitches 501 are replaced by a loop of strong twine which passes through the envelope from front to back, then back to front and tied at the front. For the purposes of providing sufficient strength to the tie, the loop is arranged to enclose at least three of the warp or weft threads in each of the outer hessian walls of the envelope. However, in each case, the finished bag 101 comprises a sealed envelope having two opposing faces connected at their centres by a connecting means such that the super absorbent polymer granules surround said connecting means.

In alternative embodiments, the faces of the envelope are connected at more than one position. For example, in some embodiments the envelope is arranged to have a length that is much larger than its width, and the front and rear faces of the envelope are connected at several positions spaced along the length of the envelope.

It is also envisaged that, instead of the envelope being formed of an outer sheet that is folded in half and sewn around three sides, it may be formed of two similar sheets that are placed one on top of the other and sewn together around all their corresponding edges. The inner wall of the envelope may also be similarly formed of two sheets or formed of one sheet folded in half, as previously described. However, in each embodiment, the resulting envelope is formed of a first face having edges that are directly connected to corresponding edges of a second face. Thus, the envelope has a structure that is easily manufactured and takes up relatively little space during storage.

Figures 6 and 7

The bag 101 is typically used with other similar bags to build a barrier to hold back water, for example flood water caused by excessive rain fall. To use the bag 101 it is first immersed in water. The water penetrates the double wall envelope of the bag and is absorbed by the super absorbent polymer granules. The granules expand and fill the bag such that the walls tend to balloon outwards. However, while other parts of the envelope walls are forced outwards, at the location of the stitches 501, the stitches hold the opposing faces of the envelope together.

The bag 101 is shown in the perspective view of Figure 6 and a cross-sectional view in Figure 7 after immersion in water. The cross-section of Figure 7 passes through the bag's stitched side 204, its central stitches 501 and its folded side 304.

As will now be understood from the preceding description, the bag 101 comprises a double-walled envelope 502, formed of an outer sheet 202 and an inner sheet 201 , that contains a water absorbent granular material 401. The opposing faces 205, 206 of the envelope are held together by stitching 501 at a substantially central location to provide the swollen bag, as shown in Figures 6 and 7, with its shape.

The stability of the swollen bag 101 on a flat horizontal surface 701 is demonstrated in Figure 7. As the stitches 501 hold the upper and lower faces 205, 206 of the envelope together, the absorbent polymer 401 is only able to push out the envelope walls surrounding the stitches and not at the stitches themselves. Consequently, instead of the lower face 206 of the bag having a simple domed shape, it has a substantially circular ridge having a depression 703 in the middle. Thus, because the bag rests on a relatively broad circular ridge, its position on the surface 701 is stable.

Figure 8

When the bag 101 is positioned on other similar bags to produce a wall for use as a water barrier, its position on those bags is also stable due to the effect of the stitches 501 on the shape of the upper and lower faces 205 and 206 of the envelopes. Thus, by way of example, the bag 101 is shown in cross-section in Figure 8 with its lower face 206 resting in a stable manner on the upper face 805 of another similar bag 801.

Figure 9 An alternative filled bag 901 is shown in Figure 9. The bag 901 is similar to bag 101 in that it includes stitching 902 attaching the rear wall of its outer envelope to the front wall, such that water absorbent granular material surrounds the stitching to provide the envelope with a shape that is stable on a flat surface. The differences of the bag 901 from the bag 101 are in the manner in which the internal walls of the envelope are attached to the outer walls. This is illustrated by Figure 10.

Figure 10

Component parts of the bag 901 are shown partly assembled in Figure 10. To manufacture the bag 901 , sheets of cotton and jute are first cut out as for bag 101. However, the next step is to fold the cotton sheet in half and sew 1001 around two edges to produce an envelope 1002 having an open end 1003. A measured quantity of super absorbent polymer (S.A.P.) is then put in the cotton envelope and said envelope is shaken to ensure that the S.A.P. is at the bottom. The cotton envelope 1002 is then laid on one half of the jute sheet 1004, such that the open end 1003 of the cotton envelope projects past the edge of the jute sheet (typically by 5 millimetres) and the sewn sides are just inside the other edges of the jute (typically by 10 to 20 millimetres). This arrangement is shown in Figure 10.

The protruding open end 1003 of the cotton envelope 1002 is folded over and the uncovered half 1005 of the jute sheet 1004 is then folded over the inner envelope. The jute envelope is then stitched around its three open edges with overstitch so as to close the inner envelope in the end-seam. Thus, at this stage, the inner envelope 1002 is only attached to the outer envelope along one edge.

The bag 901 is then completed by stitching 902 (or alternatively by tying) in a similar manner to bag 101.

Claims

1 A filled bag for providing part of a temporary barrier to water, comprising: a water permeable envelope formed of a first face having first edges, and a second face having second edges directly connected to said first edges of said first face; a granular material located within said envelope, said material being of a type which absorbs water and swells up; and connecting means connecting opposing parts of said first face and said second face of said envelope, such that said granular material surrounds said connecting means, whereby when said bag is immersed in water and said granular material swells to fill said envelope, said connecting means holds said opposing parts of said faces together to provide said envelope with a shape that is stable on a flat surface.

2. A filled bag according to claim 1 , wherein said connecting means comprises stitches.

3. A filled bag according to claim 2, wherein said stitches are formed from jute yarn.

4. A filled bag according to any of claims 1 to 3, wherein said envelope comprises a woven fabric.

5. A filled bag according to claim 4, wherein said woven fabric is hessian.

6. A filled bag according to claim 4 or claim 5, wherein said envelope has edges of said fabric held together by stitches.

7. A filled bag according to any of claims 1 to 6, wherein said envelope has a wall comprising an outer layer and an inner layer attached to said outer layer to maintain the position of the inner layer within the outer layer, and said granular material is located inside said inner layer.

8. A filled bag according to any of claims 1 to 7, wherein said envelope has a wall comprising an outer layer formed from a woven fabric and an inner layer formed from a relatively finer fabric.

9. A filled bag according to any of claims 1 to 8, wherein said envelope is formed from a folded piece of woven fabric that is stitched around edges of said fabric to form said envelope.

10. A filled bag according to any of claims 1 to 9, wherein said material is a super absorbent polymer.

11. A method of manufacturing a filled bag for providing part of a barrier to water, comprising the steps of: forming an open-ended envelope from a sheet of water permeable fabric by connecting edges of a first face to edges of a second face; obtaining a granular material which absorbs water and swells up; putting said granular material within said envelope; closing the open end of said envelope; and connecting said first face of said envelope to said second face of said envelope by a connecting means, such that said granular material surrounds said connecting means to provide said envelope with a shape that is stable on a flat surface when said granular material is swollen by immersion in water.

12. A method of manufacturing a filled bag according to claim 11 , wherein said connecting means comprise stitches.

13. A method of manufacturing a filled bag according to claim 12, wherein said stitches are formed from jute yarn.

14. A method of manufacturing filled bag according to any of claims 11 to 13, wherein said envelope comprises a woven fabric.

15. A method of manufacturing filled bag according to claim 14, wherein said woven fabric is hessian.

16. A method of manufacturing filled bag according to claim 14 or claim 15, wherein said envelope is formed by sewing together edges of said fabric.

17. A method of manufacturing filled bag according to any of claims 1 1 to 16; wherein said envelope is formed with a wall comprising an outer layer and an inner layer attached to said outer layer to maintain the position of the inner layer within the outer layer, and said granular material is put inside said inner layer.

18. A method of manufacturing filled bag according to any of claims 1 1 to 17, wherein said envelope is formed with a wall comprising an outer layer of a relatively coarse woven fabric and an inner layer of a relatively fine fabric.

19. A method of manufacturing filled bag according to any of claims 1 1 to 18, wherein said envelope is formed from a folded piece of woven fabric that is stitched around edges of said woven fabric to form said envelope.

20. A method of manufacturing filled bag according to any of claims 11 to 19, wherein said material is a super absorbent polymer.

21. A filled bag for providing part of a temporary barrier to water, comprising: a water permeable envelope; a granular material located within said envelope, said material being of a type which absorbs water and swells up; and connecting means for connecting opposing parts of said envelope, such that said granular material surrounds said connecting means, whereby when said bag is immersed in water and said granular material swells to fill said envelope, said connecting means holds said opposing parts of said envelope together to provide said envelope with a shape that is stable on a flat surface, wherein said envelope has a wall comprising an outer layer and an inner layer attached to said outer layer to maintain the position of the inner layer within the outer layer, and said granular material is located inside said inner layer.

22. A filled bag according to claim 21 , wherein said connecting means comprises stitches.

23. A filled bag according to claim 22, wherein said stitches are formed from jute yarn.

24. A filled bag according to any of claims 21 to 23, wherein said envelope is formed from a textile fabric.

25. A filled bag according to any of claims 21 to 24, wherein said envelope has a wall comprising an outer layer formed from a woven fabric ^■ and an inner layer formed from a relatively finer fabric.

26. A filled bag according to any of claims 21 to 25, wherein said envelope is formed from a folded piece of woven fabric that is stitched around edges of said fabric to form said envelope.

27. A filled bag according to any of claims 21 to 26, wherein said material is a super absorbent polymer.