EP1940701A1 - Container for a fluid - Google Patents

Abstract

A container for the temporary storage of fluids and in particular liquids. The container comprises a flexible outer sack (211) enclosing a, flexible inner fluid bladder (210) having- an inlet port (215) and an outlet port (216) so that fluid may be introduced and drained from the inner bladder. The inner bladder is configured with a plurality of folded regions such that when a fluid is introduced into its interior the inner bladder unfolds within the outer sack in such a way that reduces the risk of pinching of the inner bladder resulting in uneven filling and tearing of the bladder. The fluid container is suitable for use with conventional crate and pallet systems for the transport of liquids and semi- liquids.

Description

CONTAINER FOR A FLUID

The present invention relates to a container for transporting fluids, and in particular although not exclusively, to a container for liquids and semi-liquid fluids.

It is known to transport liquids in bulk by container of the type complying with international standards as regards scantlings and securement points, whereby such containers can be moved by road, rail and ship.

Conventional containers for use in shipping, storing and dispensing liquid or semi-liquid fluids often consist of either "bottle and cage" arrangements, or composite corrugated containers. The "bottle and cage" arrangements comprise a semi-rigid plastic bottle that is supported within a wire-bound exterior skeleton. This configuration requires the end user to utilize significant warehouse space to store the spent container until it can be returned to a distributor to be cleaned and reconditioned for reuse. The known composite corrugated containers are intended for one-time use, and support a flexible interior bag. These containers require an initial user to assemble the container as well as an assortment of fitments that include a corrugated cassette that holds the bag and positions it for filling, and a corrugated cap that is assembled and placed on top of the container subsequent to filling.

The addition of steel supporting structures which are external to an inner plastic container vitiates the corrosion-resistant advantage of a container which is made purely of plastic material. In addition, the external metal containers have a tendency to move relative to the inner liquid container when handled and transported. This increases the risk of damage to the inner liquid container during transportation due to possible abrasion with corroded parts of the outer metal container or parts of the container that have been damaged during handling. These corroded or damaged parts may pierce the liner separating the liquid container from the metal outer container.

Another problem is that the initial user often must then attach the assembled corrugated composite container to a wooden pallet that is used as a base for the container. Attaching the pallet usually requires heavy-duty plastic straps that wrap around both the pallet and the container to hold them together. These parts all require the handler to inventory and keep track of the various components. There is also the problem of having to provide the manpower and space necessary to assemble them.

Another problem with container-within-a-container systems is the cost. Such systems significantly increase the cost of production over single containers. They are also heavy relative to a single container.

WO86/07578 describes a system for aseptic holding of fermentable liquids in flexible containers that are immersed in water or another liquid whilst being filled. The surrounding liquid is kept in outer tanks made of concrete or plastic. Since the containers, when they are filled with liquid product are immersed in liquid, the loads acting on the container wall remain low. The system is intended for storing liquid foods and wines that are not subject to anaerobic bacterial infection but for which the presence of air is detrimental. The system comprises an outer tank containing water, wine or any other supporting fluid, into which a liquid-tight empty bladder or bladders are first submerged, then filled with liquid food or any other liquid requiring storage. This ensures that there is no head space in the vessel when it is being filled.

Therefore, there is a need for a transportable, reusable, robust, flexible, container which can be easily filled with a fluid, transported and recycled after use. It is also desirable that such a system can be used with conventional filling and pallet systems.

A container or packaging is provided configured for the temporary storage of fluids and in particular liquids. The present container is designed for ease of storage prior to use and is configured to be compressed into a 'flat-pack' so that a plurality of containers may be stacked one on top of another to minimise storage space prior to use. The present container is further configured for ease of filling with liquid or semi-liquid fluid which in turn significantly reduces the time required to fill the container with fluid. The present invention is particularly suitable for use with automated filling units and processes. Due to its construction, the container may be easily collapsed and disposed of by an end user following use.

According to a first aspect of the present invention there is provided a container for a fluid, said container comprising: a flexible outer sack having an upper surface and a lower surface, the upper and lower surfaces being separated by side walls; a flexible inner sack positioned within said outer sack and having a plurality of folded regions wherein said inner sack is capable of unfolding within the said outer sack when a fluid is introduced into said inner sack; a fluid inlet port provided at said upper surface of said outer sack and positioned eccentrically towards one of said side walls, said inlet port configured to allow fluid to be introduced into an interior of said inner sack through said outer sack; a fluid outlet port configured to allow fluid to exit said interior of said inner sack through said outer sack; and attachment means configured to secure said inner and outer sacks together at the region of said outer sack between said upper surface and said side walls and the region between said lower surface and said side walls.

According to a second aspect of the present invention there is provided a method of assembling a container for a fluid, said method comprising: creating a plurality of folds within a flexible inner sack capable of storing a fluid, said inner sack comprising an inlet port to allow fluid to be introduced into an interior of said sack and an outlet port to allow fluid to exit said interior of said sack; and securing said inner sack in position within a flexible outer sack using attachment means so as to allow said inner sack to unfold within said outer sack when a fluid is introduced into the interior of said inner sack.

The container includes a fibre or fabric web which serves as the protective outer sack and which is wrapped around and encloses the inner liquid bladder. The outer sack is sufficiently strong in its own right to support the liquid contents of the vessel even when unsupported by any support framework, in the form of a metal crate. In one embodiment, the liquid vessel is generally substantially cuboid and the outer framework is substantially cuboid. The inlet and outlet ports are of known construction and may contain valves and caps are used to fill and discharge the vessel. Preferably, the inlet and outlet ports are circular. -A-

As used herein, the term fabric means a web of woven material such as a web formed from woven polypropylene fibre. Similarly, a fibre web refers to a web woven from synthetic fibres.

The liquid vessel is adapted so that the inner sack automatically unfolds as the vessel is filled with liquid. The liquid vessel is of a generally rectangular shape and is usually in the form of a cuboid. The outer protective sack may be provided with one or more attachment tabs at one of the top edges of the liquid vessel. In this context, the top edges are those edges which define the upper face of the liquid vessel which is not supported or covered by the outer framework when the transport system is in use. hi this embodiment, the inlet aperture is provided in the top face of the liquid vessel and is positioned eccentrically so that it is close to one of the top edges of the container, this edge being the connection region of the inner and outer sacks comprising the connection means.

Where the container comprises attachment tabs, the or each tab present in the top edge of the liquid vessel are fastened to and may pass through the outer protective sack and are fastened to the inner sack. The or each tab thus serves to secure a part of the outer surface of the inner sack to a corresponding adjacent part of the inner surface of the outer sack in the vicinity of a top edge of the vessel. These attachment tabs are referred to as upper tabs.

The or each tab may be fastened by chemical and or physical means to the outer and inner sacks. The means of fastening is preferably by thermobonding, using adhesive and/or stitching.

One or more corresponding tabs are also provided on the corresponding bottom edge of the liquid vessel which forms one edge of a rectangle with the top edge. The bottom edges are defined as those which when the vessel is in position inside the outer support container, are positioned in contact with the bottom inside edges of the outer support container. These attachment tabs are referred to as lower tabs. The or each lower tab provided on the bottom edge of the liquid vessel extend between the outer protective sack and the inner sack, hi a similar manner to the function of the upper tab(s) provided on the top edge, the or each lower tab serves to fasten the outer side of the inner sack to the adjacent inner face of the outer sack in the vicinity of the bottom edge.

The outlet port or aperture may be provided in the top face of the liquid vessel or may be provided in the side face of the vessel which is bounded by the top and bottom edges having tabs. Preferably the outlet port is positioned so that it is in the top face and close to the top edge or in the side face and close to the bottom edge containing the or each attachment tab.

An advantageous feature of the liquid container of this embodiment is the fact that the liquid bladder which is formed by the inner sack is able to automatically unfold within the outer sack as the liquid vessel is being filled. Another benefit of the auto filling of this embodiment is that it avoids the problem of inexperienced operators who typically handle and pack bulk liquid containers. In a traditional system if the container is not accurately cited there is the risk of pinching or trapping parts of the sides of the flexible container which can lead to leakage.

The automatic unfolding of the bladder is achieved without any folding or trapping of the inner sack occurring during the filling operation. This is achieved due to the relative position of the attachment means and preferably upper and lower attachment tabs. Similarly, the pattern of folding of the inner layer which forms the liquid vessel when it is installed in the outer protective cover during manufacture is also important in facilitating automatic opening. Moreover, the outer sack is also configured with folded regions such that at least some of the folded regions of the inner sack are positioned against and supported by the folded regions of the outer sack. Preferably the lower face of the outer sack comprises at least one folded region such that a portion of the bottom face and the inner sack extend from the bottom edge at an angle less than 90° relative to a substantially vertically aligned side wall. Preferably, the inner sack extends from the bottom edge at an angle between 30° to 70° relative to the substantially vertically aligned side wall.

The or each upper tab (provided on the top edge of the container) may also be fastened around corresponding supporting bracket(s) on the outer container or around the support framework. In this embodiment in addition to supporting the outer protective sack so that it does not fall down within the outer support container, the or each upper tab thus also provides support for the inner sack so that it does not fall down within the outer protective cover when the liquid container is placed in the outer container which forms the shell of bulk liquid transport system. The or each tab present on the bottom edge is not secured to the outer container but simply serves to secure the inner sack to the outer sack. In an alternative preferred embodiment the liquid vessel is fastened to the outer container by means of one or more securing straps which are provided at or near the top edge containing the upper tabs. The tabs may use any conventional means of securing the top edge of the liquid container to the framework and preferably comprise hook and loop-type fastenings.

The sides and bottom of the outer sack of the liquid vessel drop inside and towards the bottom of the outer container when placed within the outer container. This is due to the overall weight of the liquid container. The adjacent part of the inner sack is constrained to follow and adopt the same position on account of the relative positions of the upper and lower tabs.

This means that when the flexible liquid vessel is secured by means of the upper tabs to the top edge of an outer container and is allowed to drop down into the outer container, the inner sack forms a corresponding inside face of the flexible liquid container which is substantially vertical.

When liquid is introduced to the container via the inlet port it is able to fall directly down the substantially vertical inner side wall of the inner sack until it reaches the folded part extending from the vertical side wall at an angle around 45°. This folded part of the inner sack will be resting on the inside of the bottom face of the outer sack when the liquid container is in use. The introduction of liquid facilitates unfolding of the folded inner sack as liquid permeates the folded inner bladder and gently forces it open.

As the liquid level rises, the inner liquid sack unfolds further and further in such a way that the inner liquid sack substantially covers the entire base area of the outer container (insofar as it is able to do so within the constraints of the outer protective sack). Gradually, as the liquid level in the vessel rises contact between the inner sack with the opposite vertical face of the outer sack (and the other two side faces) increases until the vessel is full. At that time corresponding parts of the inner sack press against and are supported by the outer sack which in turn is supported by the outer container.

One advantage of this embodiment is that it is possible to insert a probe or a filling or emptying device or for analysing the nature or quality of the material into the liner without any risk of puncturing the inner liquid vessel.

Ordinarily it has been difficult to fill a flexible vessel which is formed from more than a single wall because of folding or pinching of the inner material relative to the outer material. In the case of the present invention, the location of the tabs and its method of folding ensures auto filling can occur without any trapping or pinching.

A further important feature is the location of the seam that is present in the inner liner. The seam is therefore provided such that the seam forms a significant angle relative to the horizontal. This angle should be at least 30°. Thus the seam generally runs either in a vertical or diagonal direction. When the seam is, for example, diagonal (such that the angle of the seam is at approximately 45° to the horizontal), the film is pulled out into the corners of the outer sack as the inner liquid sack gradually unfolds within it. Similarly, in the case of a vertical seam i.e. one at 90° to the horizontal, the material forming the inner sack is pulled out towards the vertical face including the tabs and its corresponding opposite vertical face. The inner liquid bladder has a slight excess of material relative to the outer protective layer so that it may completely fill the cuboidal void defined by the outer sack.

In one arrangement of this embodiment, one or more auxiliary securing tabs are also provided on the opposite top edge of the outer protective layer. These may or may not penetrate the outer layer but are not fastened to the inner layer. The or each securing tab, when present, is used to secure the corresponding top edge to corresponding supporting bracket(s) on the outer container or around its framework. This provides support for the outer protective layer so that it does not fall down within the container when the liquid container is placed in the outer supporting container which forms the shell of bulk liquid transport system.

A substantially cuboid liquid container of this type is intended for single use though it may be reused. Under such circumstances the autofilling capability will be reduced as the original folding pattern has been lost. In a single trip application, after filling, transportation and emptying at the destination the flexible liquid container can be recycled as it is made entirely of plastics material. The bag may be provided in a sterile form such that prior to use the bag is sterile and each single use enables material to be transported in a sterile environment.

Preferably, the inner layer is formed of polyethylene. Preferably, the inner layer is aseptic and may comprise a suitable coating. Preferably, the inner layer may be formed of a laminate comprising two or more layers in particular three layers of rectangular sheet polymer material, heat welded together at the perimeter of the as formed sack.

The outer sack may comprise from 40 to 70% by weight of the vessel, and more preferably comprise from 45 to 55% by weight, or about 50% by weight.

In an embodiment, the outermost support framework or crate may be made of a mesh or sheet material, and in particular metal sheet.

The use of multi-layer co-extrusion for constructing the inner sack of the liquid vessel allows several individual material sack to be extruded together into a single laminated film so as to provide an inner layer with the desired mix of properties. For example, such a film can be designed to allow a controlled level of oxygen permeation or be impermeable to oxygen. Suitable oxygen barrier layer are constructed of materials such as ethylene vinyl alcohol.

It may also be desirable to include a barrier layer which is moisture resistant to protect against moisture sensitive liquids. Thus, one or more moisture barrier layers can be included, on one side or on each side of the oxygen barrier layer. It may also be desirable to comprise into the laminate forming the inner sack, one or more layers of material which have low permeability to flavours and/or fragrances.

In an embodiment, the outer layer is formed of polypropylene. The outer layer may also be a laminate of two or more layers, with at least one being a woven layer.

The liquid container of the present invention provides protection against accidental puncture and damage and provides a number of advantages. The protective outer sack is strong and resistant to tearing. The protective sack also provides a barrier to the ingress of dirt and moisture and it does not lose strength on contact with water. The protective sack is able to provide protection against impacts sustained during handling, transportation and storage. It is relatively cheap and easy to manufacture, and ideally can also be re-used a number of times. After it has been used a number of times the component materials can easily be recycled or be separated from one another as necessary and then recycled.

It is intended that the product be as environmentally friendly as possible in the sense that it is intended to be reused so preventing disposable single trip waste packaging and avoiding UK packaging waste levies after its first trip. Even when damaged it is made from recyclable materials and thus and will be recyclable, whereas the current methods of packaging have plastic and cardboard mixtures and may contain other components so they are not easily recyclable.

The protective outer sack may be constructed of a single web of fibre. Alternatively, the outer sack may be formed of more than one fibre web fastened together by seams, by adhesive or by thermobonding.

In one embodiment, the outer sack may be retained in contact with the corresponding region of the inner sack by folding over at least one portion of the two sacks to form a seam. These overlapping folded portions forming the seam may be glued, stitched or thermobonded to one another so as to provide a means of attachment. In other embodiments, the outer protective sack and inner bladder may be joined directly to one another or may be joined to one another via another material including in particular at least one attachment tab comprising an adhesive backed fabric-based tape. Preferably the tape comprises a woven material. Preferably the container comprises two tabs provided at the upper edge and two tabes provided at the lower edge representing two edges of the side wall positioned closest to the inlet port.

In an embodiment, seams which are effective to join the inner and outer sack of the liquid vessel define fold lines. The seams separate different regions of the outer surface of the inner barrier sack of the liquid vessel from one another. The seams may be arranged so as to provide tension in the inner and/or outer sack. This assists folding and opening out of the vessel. Hence the seams may be arranged in a manner to allow automatic or at least assisted 'opening-out' of the container when the container is laid flat and/or when it is introduced into the supporting metal outer container.

In a further embodiment, the container is substantially cuboid and the seams serve to separate the faces of each side from its neighbour and from the top and bottom faces of the container separated by side walls to define a cuboid shape.

In a preferred embodiment, the outer protective sack of the liquid container includes a second layer of plastics material. This may be woven or non- woven. Preferably the second layer of plastics material is polypropylene.

In another embodiment, the outer sack is formed from woven synthetic fibre. Preferably the outer layer is formed from woven polypropylene.

The web of fibre or fabric is made of a flexible material, preferably a polymer. Ideally, the polymer is a polyolefin and is preferably polypropylene or polyethylene. The polymeric material is woven into a web from polymeric fibres. Ideally, the web is coated both sides with a waterproof coating to render it impervious to water and also to enhance the resistance to the ingress of dirt and other materials. Polypropylene has the advantage that it sufficiently strong to withstand the tensile forces that will occur when the vessel is loaded and/or lifted. At the same time, the fabric should be sufficiently flexible so as to adopt the required shape but also be capable of being folded. Polypropylene is ideal for this.

The outer sack may be coated on one or both sides. Ideally, it is coated at least on the outside for ease of cleaning, hi an alternative embodiment, and particularly when producing an automatic opening liquid container, the coating is on the inside of the outer protective sack. This reduces friction as the inner barrier layer unfolds during filling. Preferably the coating is an antimicrobial coating and has the further advantage of eliminating bacterial growth with the container.

The weight of the outer layer is preferably in the range 100 to 300 gm^"2, and more preferably in the range 160 to 240 gm^"2 because this provides the best compromise between folding ability and durability. Generally, the coating will account for a further 20 to 35 gm^"2 of the weight of the web. The coating is preferably a polypropylene coating.

In one embodiment where the container is not an automatic filling container, the advantage of coating the outer material on both sides is, on the one hand, that it leads to better bonding of the protective outer layer to the inner liquid container and, on the other hand, it means that the outer surface of the outer protective layer is easier to clean and does not retain dirt in the fabric weave.

The coating is applied to the woven fabric by melting the material forming the coating, usually polypropylene, and feeding the molten material through a die in semi-molten form. The coating is then brought in sheet form into the locality of the fibre web and passed through a series of chilled rollers and tensioned in accordance with procedures well known in the art. The provision of a coating on both sides may be achieved in a two stage process or may be achieved in a single process.

In another embodiment, the fibre or fabric web is provided with one or more handles or loops to facilitate lifting and handling of the liquid container. In another embodiment, the outer sack may incorporate a region which is adapted to carry identification marks relating to the goods such as the nature and weight of the goods, safety information and handling instructions.

The liquid vessel is compatible with known filling systems in terms of the position of the inlet and outlet ports. Hence it can be filled by automatic filling apparatus.

A specific implementation of the present invention will now be described by reference to the following drawing in which:

Figure 1 shows a liquid vessel according to the invention placed in a framework which is a rigid supporting outer container,

Figure 2 shows a side view of a bulk liquid transport system according to one embodiment of the invention,

Figure 3 shows a side view of a flexible liquid container when full of liquid according to one embodiment of the present invention,

Figure 4 shows a side view of a flexible liquid container when full of liquid according to another embodiment of the present invention,

Figures 5 a, 5b and 5c are partial cross sections of a container according to one embodiment of the invention, and

Figures 6a, 6b and 6c are plan views of the inner layer showing the folding pattern.

hi Figure 1, the transport and storage system includes an outer container which is in the form of a rigid framework 1. In Figure 1 this is shown in the form of a cuboid which has its sides and base made of sheet metal. The sides and base could be in the form of a mesh however. Vessel 2 is placed within framework 1. Vessel 2 has an outer layer 3 and an inner layer 4 and includes inlet aperture 5 in top face 6 of the vessel. Outlet aperture 7 is provided near the bottom of one of the side faces 8 of the vessel 2 and is able to pass through a corresponding aperture 9 in the framework 1.

In the embodiment shown in Figure 1, the vessel 2 is substantially cuboid when in open configuration and has four side faces 8, a bottom 10, and a top 6. other shapes are however possible. A filling socket 11 is formed as part of the aperture 5 and is provided with a lid 12. A tapping socket 13 is formed as part the aperture 7 and is provided with a tapping fixture or a cap 14.

The vessel 2 is positioned with its bottom 10 on the bottom 15 of the framework 1 and generally has a shape matching that of the bottom 10. The underneath 16 of the framework 1 includes bearers 17 and is designed to be handled by means of forklifts, storage shelf operating devices and similar transport means.

Handles 18 are provided near the top of one or more sides 8 of the vessel 2 or on the top face 6 of the vessel 2 to allow manipulation.

Outer 3 and inner 4 layers of vessel 2 are joined at seams 19 adjacent to and surrounding apertures 5 and 7, and by seams 20 at the edges of the vertical sides.

In Figure 2, outer support container 201 provides support for cuboidal bulk liquid container 202 which is contained therein. Tabs 203 are used to secure top edge 204 to suitable supports 205 on outer container 201. Corresponding tabs 206 are provided in the bottom edge of the container but are not used to secure the flexible container to the outer supporting container 201. Additional auxiliary tabs 207 are provided along the opposite top edge 208 to top edge 204 and serve to fasten the outer protective layer to outer support container 201. The liquid container 202 sits on the base 209 of the support container 201. Flexible liquid container 202 is itself formed of an inner liquid vessel 210 and an outer protective cover 211. Inner liquid vessel 210 is folded when the container 202 does not contain any liquid and it can be seen that at least a portion 212 of inner vessel 211 is substantially vertical and follows the vertical faces of the corresponding portion 213 of the outer protective liner and the vertical wall 214 of container 201. The container also includes an inlet 215 and an outlet 216 which are positioned near the top edge 204 and the bottom edge 217 of the flexible container respectively. It would be equally possible for both the inlet and the outlet to be positioned in the top face 218 of the container.

Figure 3 shows a schematic diagram of the inner layer 301 in the fully opened out configuration within outer layer 302 that it would be in when full of liquid 303. This configuration reveals diagonal seam 304 which runs from the vicinity of tab 305 in top edge 306 and close to inlet aperture 307 to the opposite bottom edge 308 of inner layer 301. The outlet aperture is omitted for clarity.

Figure 4 shows a schematic diagram of the inner layer 401 in the fully opened out configuration within outer layer 402 that it would be in when full of liquid 403. This configuration reveals vertical seam 404 which runs from the vicinity of tab 405 in top edge 406 and close to inlet aperture 407 to the bottom face 408 of inner layer 401. The outlet aperture is omitted for clarity.

The sequence of Figures 5a, 5b and 5c show how the inner layer 501 unfolds automatically as liquid 502 is introduced into the container 503. Upper and lower tabs 504 and 505 hold at least one side 506 of inner layer 501 in a vertical position adjacent to the vertical side 507 of outer layer 508. As soon as sufficient liquid 502 has been introduced into the liquid vessel the bottom 503 becomes taut and substantially covers the entire base area of base 509 of the outer metal container 505. In this view an inlet aperture 510 is shown and the outlet aperture which is optionally present is not shown for clarity. As the container fills, the inner layer 501 bears against and is supported by the other vertical sides 511 of the outer protective layer, which are in turn supported by the walls of the supporting container (not shown).

The sequence of Figures 6a, 6b and 6c show how the inner layer 601 is folded. The folding sequence is important to the success of the automatic opening. The folding process must take place on the same side as the filling gland as this ensures correct opening of the inner barrier layer on filling. The distance between the upper and lower tabs is also important as shown below. Figure 6a shows a fully folded inner layer. Here the inner layer is in its configuration in the form in which it will be present in the outer flexible container when forming part of a flexible liquid vessel according to the invention which is ready for use. Upper tabs 601 are present in the top edge and inlet / outlet aperture 602 is also present near the top edge and is partly obscured by folded parts 603. Folded part 604 is folded on top of parts 603 as a subsequent fold and reveals lower tabs 605 positioned in an appropriate place so that the distance between upper tabs 601 and lower tabs 605 corresponds with the height of the side wall of the outer container for which the liquid container is destined.

Figure 6b shows inner layer 601 once it has been unfolded once relative to the view in Figure 6a or folded over once relative to the view in Figure 6c. Folding part 606 once along axis X-X leads to folded part 604 in Figure 6a with the top edge of the folded part 604 then reaching line 607. The lower tabs 605 are underneath the inner barrier layer as shown in Figure 6b and are only apparent once the material is folded, then being disposed on the upper side of the inner barrier layer so they can be viewed.

Figure 6c shows inner layer 601 once it has been unfolded a further time. Figure 6c shows the inner barrier layer having a single fold from each side parallel to its long axis. The first folds in the open sheet forming the inner barrier layer are thus made along lines Y-Y and Z- Z. Upper tabs 601 are visible in the top edge of the inner barrier layer and lower tabs 605 remain hidden on the bottom side of the inner barrier layer.

Claims

CLAMS

1. A container for a fluid, said container comprising: a flexible outer sack having an upper surface and a lower surface, the upper and lower surfaces being separated by side walls; a flexible inner sack positioned within said outer sack and having a plurality of folded regions wherein said inner sack is capable of unfolding within the said outer sack when a fluid is introduced into said inner sack; a fluid inlet port provided at said upper surface of said outer sack and positioned eccentrically towards one of said side walls, said inlet port configured to allow fluid to be introduced into an interior of said inner sack through said outer sack; a fluid outlet port configured to allow fluid to exit said interior of said inner sack through said outer sack; and attachment means configured to secure said inner and outer sacks together at the region of said outer sack between said upper surface and said side walls and the region between said lower surface and said side walls.

2. The container as claimed in claim 1 wherein the said outer sack comprises a plurality of folded regions.

3. The container as claimed in claims 1 or 2 wherein said inner sack comprises at least one top layer bonded to at least one bottom layer to define a sack sealed towards its perimeter.

4. The container as claimed in claim 3 wherein said inner sack comprises three top layers and three bottom layers.

5. The container as claimed in claims 3 or 4 wherein said inner sack is substantially rectangular wherein said inlet port is positioned towards one edge extending across the width of said rectangle.

6. The container as claimed in claim 5 wherein the two edges along the length of said rectangle are folded inward on top of said upper layer.

7. The container as claimed in claim 6 wherein the second edge of said rectangle extending across its width is folded a first and second time on top of said upper layer.

8. The container as claimed in any preceding claim wherein said upper surface and said lower surface of said outer sack are connected respectively to said side walls by at least one seam.

9. The container as claimed in claim 8 when a distance between said inlet port and said seam extending between said upper surface and said side walls is less than 30 cm.

10. The container as claimed in claim 8 wherein a distance between said inlet port and said seam extending between said upper surface and said side walls is between 10 to 15 cm.

11. The container as claimed in any preceding claim wherein said attachment means comprises at least one attachment tab extending between said outer and inner sacks.

12. The container as claimed in claim 11 wherein at said least one attachment tab is secured to said inner sack by adhesive.

13. The container as claimed in claims 11 or 12 wherein said at least one attachment tab is secured to said outer sack by stitching.

14. The container as claimed in any one of claims 11 to 13 wherein said at least one attachment tab comprises an adhesive backed fabric-based tape.

15. The container as claimed in any preceding claim wherein said inner sack comprises a polyethylene material.

16. The container as claimed in any preceding claim wherein said outer sack comprises a woven polypropylene material.

17. The container as claimed in any preceding claim further comprising an antimicrobial coating provided at an interior surface of said outer sack.

18. The container as claimed in any preceding claim further comprising a plurality of securing tabs extending from an exterior surface of said outer sack.

19. The container as claimed in claim 18 wherein said securing tabs comprise hook and loop-type fastening tabs.

20. A method of assembling a container for a fluid, said method comprising: creating a plurality of folds within a flexible inner sack capable of storing a fluid, said inner sack comprising an inlet port to allow fluid to be introduced into an interior of said sack and an outlet port to allow fluid to exit said interior of said sack; and securing said inner sack in position within a flexible outer sack using securing means so as to allow said inner sack to unfold within said outer sack when a fluid is introduced into the interior of said inner sack.

21. The method as claimed in claim 20 further comprising creating a plurality of folds within said outer sack wherein the folded inner sack is positioned against the folds of said outer sack.

22. The method as claimed in claims 20 or 21 further comprising attaching said inner sack to said outer sack at an upper region of said container between an upper face and a side wall of said outer sack.

23. The method as claimed in claim 21 further comprising attaching said inner sack to said outer sack at a lower region of said container between a lower surface and a said wall of said outer sack.

24. The method as claimed in any one of claims 19 to 22 further comprising attaching said inner sack to said outer sack using at least one attachment tab secured to said inner sack via an adhesive and secured to said outer sack via stitching.