AU2014200708A1 - Lined Bag - Google Patents

Abstract

Abstract A flexible intermediate bulk container (FIBC) for transport and storage of bulk 5 material. The FIBC comprises an outer bag sewn from outer bag fabric plus an inner liner made from liner fabric fastened to the inside of the bag. Side wall portions, a top and a bottom define outside surfaces of the container. The top includes a closable opening. The liner fabric is made of a woven material laminated with plastics film. The liner is welded at its seams such that said seams are waterproof. )7 $6 6 18

Description

1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION for the invention entitled: "Lined Bag" The invention is described in the following statement: 2 LINED BAG 5 Field of the Invention This invention concerns the use of containers for transport and storage of bulk materials. It has particular application to the transport and storage of dangerous goods. It particularly concerns the use of containers known to those skilled in the art 10 as Intermediate Bulk Containers (IBCs) and containers known as bulk bags or Flexible Intermediate Bulk Containers (FIBCs). FIBCs are flexible bags made from woven fabrics, and used to transport and store powdered, granular, particulate, pelletised or briquetted solid materials. 15 Background to the Invention FIBCs are commonly made from heavy textile fabrics typically woven from polyolefins such as polypropylene and polyethylene. FIBCs are commonly manufactured with a base of about 1100mm square and side walls about 1100mm 20 high. They therefore fit neatly on a conventionally sized shipping pallet. The most common FIBCs have only a single skin of woven textile. It is usually fitted with a fill spout and often a discharge spout which are tied closed by cord or other means. Designs vary according to the rated capacity of the FIBC and whether it is for 25 a single use only or is reusable. FIBCs sometimes include an inner bag made from polyethylene or polypropylene film to provide a barrier against moisture and/or gases. This inner bag may be closed by a tie or by heat sealing to provide a fully sealed package for the enclosed material. 30 FIBCs are sometimes used for the carriage of dangerous materials in situations where Group 2 or Group 3 containers are mandated. The appropriate authorities must certify 3 the package for transportation. However a substantially higher level of performance is required for Group 1 containers which may be used for particularly dangerous goods. The general practice is for Group 1 goods to be transported only in rigid containers. An example of Group 1 dangerous goods is sodium cyanide. This is widely used as a reagent in mineral processing, particularly for gold extraction, and large quantities are transported long distances from manufacturing plants to mine sites. It is commonly supplied in the form of small briquettes or pellets. Normal current practice in 10 Australia is for such sodium cyanide briquettes to be transported in a rigid composite Intermediate Bulk Container (IBC) which comprises an FIBC inner primary package and a plywood box outer secondary package. A polyethylene film box-liner in the box encapsulates the FIBC and is closed by heat sealing. The polyethylene box-liner is placed in the box before the filled bag is lowered in, and the liner is then drawn up 15 and sealed. Such IBC's are placed in an ISO shipping container with 20 boxes per container and transported to mine sites. At the mine site, operators open the box and cut open the plastic box liner before lifting the bag (without the box liner) over a discharge spike attached to and above a hopper. The bag is then lowered onto the spike which ruptures the bottom of the bag allowing the sodium cyanide to fall out of 20 the bag and into the hopper. During the process of filling the FIBC, the sodium cyanide briquettes at a temperature of about 1 00'C are loaded into the bag through its fill spout which is tightly held to prevent the very fine dust present escaping from the fill spout during the filling 25 process. However for bags which have a stitched construction, the seams themselves and the small holes created by the stitching needles along the seams allow a small amount of very fine sodium cyanide dust to escape from the bag. Also, as the briquettes cool they emit about 1 litre of aqueous condensate which must be contained within the IBC. 30 There have been attempts to alleviate this escape of dust and contain the condensate by adding a further plastic film liner bag inside the fabric bag. With this 4 configuration, at the discharge point when the FIBC is lowered onto the discharge spike, the spike ruptures the bottom of both the bag and the liner. However such a bag liner of plastic film commonly causes hang-up of the product because, as the product discharges, the liner moves away from the wall of the bag and often forms 5 pouches that hold some briquettes during the discharge process at the mine site. This is exacerbated because the film of the liner often stretches greatly before it is ruptured by the spike, thus leading to a bagginess which facilitates the formation of the pouches. Also sometimes the film of the liner tears excessively and fragments of the liner fall into the hopper which then creates problems with the system for conveying 10 the pellets away from the hopper. Furthermore, with a packaging system incorporating a bag liner and a box-liner as described above, at the unloading point the operators then need to handle a contaminated bag liner and box liner as well as the fabric bag. 15 The present invention reduces the escape of dust during the filling operation, reduces the potential for product hang-up on a liner during discharge, and reduces the number of contaminated items to be handled after unloading. 20 Summary of the Invention In one aspect the invention provides a flexible intermediate bulk container for transport and storage of bulk material, said flexible intermediate bulk container comprising an outer bag sewn from outer bag fabric plus an inner liner made from 25 liner fabric and located inside the outer bag, and wherein: - bag side wall portions, a bag top and a bag bottom define outside surfaces of the container, - liner side wall portions, a liner top and a liner bottom define said inner liner, - the bag top includes a closable opening, 30 - the liner top includes a closable opening, - the liner fabric is made of a woven material laminated with plastics film, and 5 - the liner is constructed from portions of said liner fabric welded together at seams such that said seams are waterproof. Preferably said liner is fastened to the inside of said bag. 5 Preferably said bag bottom is sewn to said bag side wall portions at bottom bag edge seams, said liner bottom is welded to to said liner wall portions to form outwardly protruding flaps at bottom liner edge seams, and said flaps are sewn into said bottom bag edge seams. 10 Preferably said container has four side walls, a top and a bottom all defining a generally cuboid shape wherein a pair of adjacent said sides defines a respective vertically aligned edge therebetween and said liner is fastened to said bag by a vertically aligned flap of liner fabric fastened into said edge seams. 15 Preferably said bottom of the bag is sewn at edge seams to said side walls and the bottom of the liner is sewn into said bottom edge seams. Preferably the closeable opening in the top comprises a filling spout including a spout 20 portion of said liner surrounded by a spout portion of said bag. Preferably said outer bag fabric is a laminated fabric comprising a woven fabric with a polymer film laminated thereto. 25 Preferably said liner fabric comprises said woven material laminated on only one side with plastics film. Preferably said woven material forms one face, a first polymer film forms the opposite face and a second polymer film is bonded between said woven material and said first polymer film. Preferably said second polymer film has a lower melting point than said first polymer film. 30 Preferably said inner liner is constructed with said plastics film on the inside of the liner and said woven material on the outside of the liner.

6 In another aspect the invention provides a rigid composite container for transport and storage of bulk material, said rigid composite container comprising an inner flexible intermediate bulk container according to any one of the previous claims held within a 5 rigid outer casing which has side walls, a top panel and a bottom panel corresponding respectively to the side walls, top and bottom of said inner flexible intermediate bulk container. Preferably said rigid outer casing is constructed at least mostly of timber. In another aspect the invention provides a method of transporting and delivering a 10 toxic material in bulk, comprising: - selecting a container according to any one of the previous claims, - loading the toxic material through the closable opening and closing said closable opening, - transporting the loaded container to a destination, and 15 - lifting the flexible intermediate bulk container and supporting it over a receiving area while puncturing the bottom of the bag and liner together sufficiently for the toxic material to flow therefrom. In another aspect the invention provides a method of transporting and delivering 20 commercial grade sodium cyanide in briquette, pellet or powder form, comprising: - selecting a rigid composite container according to claim 12 or 13, - loading the sodium cyanide through the closable opening in the top of the flexible intermediate bulk container and closing said closable opening, - packing the flexible intermediate bulk container containing the sodium 25 cyanide into the rigid outer casing, - transporting the loaded rigid composite container to a destination, - removing the flexible intermediate bulk container from the rigid casing, and - supporting the flexible intermediate bulk container over a receiving area and puncturing the bottom of the bag and liner sufficiently for the sodium cyanide 30 to flow therefrom into the receiving area.

7 Brief Description of the Drawings In order that the invention may be more fully understood there will now be described, by way of example only, preferred embodiments and other elements of the invention 5 with reference to the accompanying drawings where: Figure 1 shows a container according to a first embodiment of the present invention; Figure 2 shows a liner incorporated into the container in Figure 1; and Figure 3 shows a cross section through a side edge of the container in Figure 1. 10 Description of the Preferred Embodiment and Other Examples of the Invention Referring to Figures 1 and 2, a flexible intermediate bulk container (FIBC) 10 according to the first embodiment of the present invention is formed by fastening a 15 liner 62 inside a bag 12. The bag 12 has an approximately cubic shape with four side walls 14 to 17, a bottom 18 and a top 20. A typical external size for the bag 12 would be 109cm x109cm x 125cm high. Pairs of adjacent side walls 14 and 15, 15 and 16, 16 and 17, and 17 and 18 respectively meet along vertically extending edges 22 which extend up to the top 20 where they terminate at top corners 19 of the bag. 20 The side walls 14 to 17 and the bottom 18 of the bag 12 are all made from woven fabric. A suitable fabric is a woven polypropylene fabric having a weight of about 220gsm which then has a 30gsm polypropylene/polyethylene mix film laminated onto its inner-facing surface. 25 To construct the bag 12, appropriately cut pieces of fabric are sewn together at side edge seams 21 which form the join between adjacent side walls 14 and 15, 15 and 16, 16 and 17, and 17 and 14 respectively, at top edge seams 26 and at bottom edge seams 24. Beyond each side edge seam 21, the fabric of the side walls loop out and back 30 again to the edge seam so as to project outwardly as side edge flaps 23 for the full length of the vertical edges 22 of the bag.

8 The prominently projecting flaps 23 provide substantial protection to the vertical edges 22 of the bag where it may otherwise be susceptible to damage during handling. It will be appreciated that the vertical edges 22 of a container constructed in this way are extremely strong due to the overlapping of multiple layers of fabric. 5 Four lifting loops 33 are attached at respective top corners 19 of the bag 12. These loops allow easy lifting of the FIBC 10, and enable the end user to lift the FIBC clear of a protective timber box, in which it may typically be transported, and into position over a hopper for discharging the bulk solids material from the FIBC. The loops 33 10 may be formed by fabric straps sewn onto the vertical edges 22 as shown in Figure 1. Less desirably, each loop may alternatively straddle its respective top corner 19 and be sewn instead to the respective top edge seams 26 and respective side walls a little distant from the respective top corner 19. 15 The top 20 of the bag is covered by the same fabric as the walls 14 to 17 and is fitted with a central circular loading spout 35 made of the same fabric and which can be tied closed by a draw cord 28. The spout 35 is 50cm diameter and 63cm long. Discharge is achieved by lifting the FIBC 10 over a hopper. The hopper has a conical 20 fluted spike onto which the FIBC is lowered in order to rupture the bottom 18 of the bag and so cause discharging. This method of discharge removes the need for operators to reach under the FIBC to unlock any discharge device that might otherwise need to be fitted. 25 The liner 62 has the general shape of a cuboid having four side walls 64 to 67, a top 70 having a central tubular loading spout 72, and a bottom 74. The liner 62 is formed by welding together panels of a laminated fabric. The preferred laminated fabric is a tri-layer laminate consisting of a woven HDPE fabric of about 60 gsm on one face, a polyethylene/polypropylene (PE/PP) copolymer film of about 60 microns thick on the 30 opposite face, and an intermediate layer of low density polyethylene (LDPE) film of about 20 microns thickness between the fabric and the PE/PP film, all three layers being bonded together by heating. The woven fabric preferably has a weight in the 9 range 40 to 90 gsm. The outer PE/PP film has a thickness preferably in the range of 40 to 90 microns and the intermediate LDPE film has a thickness preferably in the range of 15 to 30 microns. The laminated fabric is preferably about 300 microns thick. 5 The PE/PP face of the liner 62 is on the inside of the liner with the woven fabric face on the outside of the liner. As the cyanide briquettes are delivered to the FIBC at about 100'C, it is important 10 that the liner has a melting point sufficiently above 100 C. The PE/PP copolymer has a melting point of about 150'C. The LDPE film has a melting point lower than that of the PE/PP film. After the hot cyanide briquettes are put into the FIBC, the liner 62 is heat sealed 15 before the bag 12 has its spout 35 tied. Alternatively, but less desirably, the liner spout may be closed by twisting it into a goose neck and fastening with a twist tie. The liner 62 is constructed from five panels of the laminated liner fabric. One square panel 76 forms the bottom 74 of the liner and four identical upper panels 78 are 20 ultrasonically welded to the base panel 76 at bottom edge seams 80 and then to each other to form the side walls 64-67, the top 70 and spout 72. From Figure 2 it can be seen that each upper panel 78 comprises, at one end, a generally square portion 82 (which forms a side wall of the liner), at the other end a rectangular portion 83 (which forms a quarter of the circumference of the spout 72) and, between portions 82 and 25 83, a central tapered portion 84 (which forms a truncated triangular quarter of the top 70 of the liner). The ultrasonic welded seams are about 10mm in width and the edges of panels 76 and 78 extend approximately 40mm beyond the weld to form a bottom edge flap 88. 30 As shown in Figure 3, each side edge flap 86 of the liner is captured within the respective seam 21 down the side edges of the bag 12. The two rows of stitching down the seams 21 are approximately 25 mm in from the outer edges of the edge 10 flaps. Each bottom edge flap 88 of the liner 62 is captured within the bottom edge seams 24 around the bottom 18 of the bag. The liner 62 is preferably made slightly oversize, being higher and wider than the bag 5 12 into which it is sewn. This is so that the load is taken by the bag instead of the liner. When used for transporting sodium cyanide briquettes, the spout of the FIBC 10 is held against a loading spout/chute on the loading equipment and the briquettes are 10 poured into the bag. At this stage the bag is lightly pressurized by the incoming flow of briquettes but the fully welded liner 62 prevents powder escaping through the seams. When filled the FIBC is then lowered into an open plywood box, the liner is closed and thermally sealed and the loading spout 35 of the bag is tied-off before the box is fastened shut. The liner is completely watertight. No additional film bag is 15 required for lining the box. When unloading the sodium cyanide at its end usage site, the operators open the box and lift the bag over a fluted discharge spike attached to a hopper. The bag is then lowered onto the spike which ruptures the bottom of the bag 12 and liner 62 allowing the sodium cyanide to fall out of the bag and into the hopper. The condensate which has collected in the bottom of the liner is swept out and into 20 the hopper by the discharging briquettes. The woven component of the liner means it is much less likely to tear in a way that sheds fragments of liner into the discharge hopper. 25 A further advantage of the present invention is that at the loading point there is no need to have an operator perform the time-consuming task of correctly fitting a liner into the bag and/or the box and ensuring the respective corners all line up. An FIBC according to the present invention may be used as a container for bulk solid 30 materials other than sodium cyanide. It is applicable for other goods where sifting of fine material or vapour through the seams of an FIBC could be a problem. Although embodiments described above are used in association with an external wooden box to 11 provide for transport of Group 1 dangerous goods, some embodiments of the invention do not require such rigid outer protection. Whilst the above description includes the preferred embodiments of the invention, it 5 is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention. 10 For example, instead of the square/rectangular shape described, the bag could instead be made from fabric woven as a tube so the bag is circular in plan view and has no side seams. Alternatively the wall portions of the bag could be made of fabric woven as a tube but with a square top and bottom to the bag. 15 It will be understood that the word "powdery" when used in this specification is intended to describe materials that may have substantial hard lumps which have powder attached to their surface as well as describe materials which are essentially all powder. 20 It will be also understood that where the word "comprise" and variations such as "comprises" and "comprising" are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of any other feature or features. 25 The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge in Australia.

Claims (15)

1. A flexible intermediate bulk container for transport and storage of bulk material, 5 said flexible intermediate bulk container comprising an outer bag sewn from outer bag fabric plus an inner liner made from liner fabric and located inside the outer bag, and wherein: - bag side wall portions, a bag top and a bag bottom define outside surfaces of the container, 10 - liner side wall portions, a liner top and a liner bottom define said inner liner, - the bag top includes a closable opening, - the liner top includes a closable opening, - the liner fabric is made of a woven material laminated with plastics film, and - the liner is constructed from portions of said liner fabric welded together at 15 seams such that said seams are waterproof.

2. A flexible intermediate bulk container according to claim 1 wherein said liner is fastened to the inside of said bag. 20

3. A flexible intermediate bulk container according to claim 1 or 2 wherein said bag bottom is sewn to said bag side wall portions at bottom bag edge seams, said liner bottom is welded to to said liner wall portions to form outwardly protruding flaps at bottom liner edge seams, and said flaps are sewn into said bottom bag edge seams. 25

4. A flexible intermediate bulk container according to claim 1 or 2 wherein said container has four side walls, a top and a bottom all defining a generally cuboid shape wherein a pair of adjacent said sides defines a respective vertically aligned edge therebetween and said liner is fastened to said bag by a vertically aligned flap of liner fabric fastened into said edge seams. 30 13

5. A flexible intermediate bulk container according to claim 4 wherein said bottom of the bag is sewn at edge seams to said side walls and the bottom of the liner is sewn into said bottom edge seams. 5

6. A flexible intermediate bulk container according to any one of the previous claims wherein the closeable opening in the top comprises a filling spout including a spout portion of said liner surrounded by a spout portion of said bag.

7. A flexible intermediate bulk container according to any one of the previous 10 claims wherein said outer bag fabric is a laminated fabric comprising a woven fabric with a polymer film laminated thereto.

8. A flexible intermediate bulk container according to claim 7 wherein said liner fabric comprises said woven material laminated on only one side with plastics film. 15

9. A flexible intermediate bulk container according to claim 7 wherein said woven material forms one face, a first polymer film forms the opposite face and a second polymer film is bonded between said woven material and said first polymer film. 20

10. A flexible intermediate bulk container according to claim 9 wherein said second polymer film has a lower melting point than said first polymer film.

11. A flexible intermediate bulk container according to any one of the previous claims wherein said inner liner is constructed with said plastics film on the inside of 25 the liner and said woven material on the outside of the liner.

12. A rigid composite container for transport and storage of bulk material, said rigid composite container comprising an inner flexible intermediate bulk container according to any one of the previous claims held within a rigid outer casing which has 30 side walls, a top panel and a bottom panel corresponding respectively to the side walls, top and bottom of said inner flexible intermediate bulk container. 14

13. A rigid composite container according to claim 12 wherein said rigid outer casing is constructed at least mostly of timber.

14. A method of transporting and delivering a toxic material in bulk, comprising: 5 - selecting a container according to any one of the previous claims, - loading the toxic material through the closable opening and closing said closable opening, - transporting the loaded container to a destination, and - lifting the flexible intermediate bulk container and supporting it over a 10 receiving area while puncturing the bottom of the bag and liner together sufficiently for the toxic material to flow therefrom.

15. A method of transporting and delivering commercial grade sodium cyanide in briquette, pellet or powder form, comprising: 15 - selecting a rigid composite container according to claim 12 or 13, - loading the sodium cyanide through the closable opening in the top of the flexible intermediate bulk container and closing said closable opening, - packing the flexible intermediate bulk container containing the sodium cyanide into the rigid outer casing, 20 - transporting the loaded rigid composite container to a destination, - removing the flexible intermediate bulk container from the rigid casing, and - supporting the flexible intermediate bulk container over a receiving area and puncturing the bottom of the bag and liner sufficiently for the sodium cyanide to flow therefrom into the receiving area. 25