GB2171382A - Container with inner flexible bag - Google Patents

Abstract

A liquid container comprises an inner flexible bag or pouch 5 for containing the liquid, e.g. a beverage, supported by an outer, relatively rigid casing 2. The bag is adapted to receive in sealing engagement a dispensing assembly comprising a gas supply device 10-12, a liquid delivery tube 15 and a tap 16. In use, the surface of the liquid contained in the bag is pressurised and the pressure above the surface maintained by the gas to allow liquid dispensation. The gas supply device may include a compressed gas cylinder 11 containing carbon dioxide and a pressure control valve. Bag 5 is impermeable to the pressurising gas and atmospheric oxygen and is preferably of laminated construction, e.g. an ethylene vinyl alcohol polymer layer co-extruded between layers of low density polyolefin. An adaptor sleeve 6 is welded to an apertured end wall of the bag, an annular rib on the sleeve 6 causing the sleeve to axially interlock with the end closure of the casing 2. <IMAGE>

Description

SPECIFICATION Improvements in and relating to liquid containers This invention relates to liquid containers of the type comprising an inner flexible bag or pouch for containing the liquid supported by an outer relatively rigid casing and often referred to as the bag-in-box type.

In particular, the invention relates to a container of the said type adapted for pressure dispensing of the liquid.

The concept of the bag-in-box type system has been known for many years as providing convenient sterile linings for containers for liquid foods and beverages. The containers have generally been one of two main kinds.

The first of these is that wherein dispensing of the contents is by pouring from the inner bag which is permitted to collapse within the more rigid outer casing whereby ingress of air into contact with the container contents may be avoided.

The second kind is that wherein dispensing is effected by pressurising the space between the inner bag and the outer casing necessitating that the outer casing be substantially gas-tight.

The first kind has been applied to soups and wines for example and the second to beer bulk stored in cellars for direct dispensing to retail counters.

The use of an inner flexible bag or pouch provided a simple means of achieving not only a sterile container but a container having suitable barrier properties against the undesirable transmission of gases, thus permitting the use of more economic materials and constructions to provide the requirements of strength and rigidity in the overall container.

While the inner flexible bag or pouch has in instances been replaceable, the cheapness of the overall construction has made it feasible for retailed containers to be disposable after a single use and such disposable containers for still wines are commonplace.

Also common to the retail market place are disposable cans containing beverages such as beer.

The cans are required to be made liquid and gas tight in manufacture and sealing, the metal of the can being covered with a lacquer or plastic coating to provide a sterile or sterilizable non-tainting surface for contacting the beverage.

To facilitate the dispensing of the contents of such cans they are generally adapted to be connectable to a re-usable unitary combination of a gas supply device, delivery tube and tap whereby gas pressure may be applied to the surface of the liquid contents causing it to be dispensed via the delivery tube on opening the tape.

Difficulties can arise in the manufacture of such cans in achieving satisfactory coatings and seals and in the satisfactory filling and sealing of such cans particularly when the contents are aerated or carbonated. Further, because these containers are largely incombustible they are not readily disposed of when empty.

An attempt has been made to employ a bag-in-box type system to replace the above cans, wherein a gassy beverage is contained in a flexible bag supported by an outer casing. The bag is provided with a tap and in order to maintain the void volume above the beverage small and the dissolution of gas from the beverage correspondingly small, the outer casing is provided with a manually adjustable end wall to enable the volume occupied by the bag to be intermittently reduced as the liquid is dispensed from the bag. Satisfactory operation of this device ensures to a large extent that the degree of aeration or carbonation of the beverage is maintained correspondingly high throughout the dispensing of contents of the container. However, such satisfactory operation requires end wall adjustments during or after each quantity of the liquid is dispensed.This device is cumbersome and its use too onerous to be sufficiently satisfactory to avoid failure of operation with consequent spoilage of the contents. Further, the filling of a flexible bag or pouch with a gassy beverage is required to be done under conditions of controlled back pressure to avoid frothing, making such filling operation difficult and requiring complex equipment.

We have now found that a bag-in-box type system can be employed for the packaging of liquids, such as liquid beverages, to be dispensed in aerated or carbonated form while minimising the above disadvantages.

Accordingly, the present invention provides a liquid container of the type comprising an inner flexible bag or pouch for containing the liquid and supported by an outer relatively rigid casing characterised in that the bag or pouch is adapted to receive in sealing engagement a dispensing assembly comprising a gas supply device, liquid delivery tube and tap or outlet valve such that in use the surface of liquid contained in said bag or pouch may be pressurised and/or a pressure above said surface maintained by said gas to cause the liquid to be dispensed via the delivery tube on opening the tap or valve and in that the outer casing is constructed to restrain the bag or pouch against overinflation and to thereby maintain the integrity of the container in use. Also provided is a bag or pouch adapted for use in the container of this invention.

The bag or pouch, for the sake of brevity hereinafter referred to as the bag, of this invention may comprise any bag of moulded or welded construction which may be made liquid- and gas-tight and which has a flexibility and dimensions whereby adequate support to prevent failure in use can be gained from contact with the walls of the outer casing of the container of this invention. It will be appreciated that as a consequence of the bag having flexibility, its dimensions may not be critical.

The walls of the bag are preferably substantially impermeable to the pressurising gas and preferably also to atmospheric oxygen thus permitting ease of retention of pressure within the bag and the maintenance of quality of its liquid contents particularly where these may be adversely affected by ingress of oxygen. A considerable range of films, foils and sheet materials including laminates have been developed from which materials for the walls of the bag may be chosen in order to achieve the desired strength and barrier properties. The materials employed heretofore for the walls of bags for use in bag-in-box systems for still wines may be considered for use for walls of the bags of the present invention, subject to strength and other requirements being met, for contact with sparkling wines and beers for example.In the majority of cases it has been the practice to employ a multi-laminae and/or laminated structure of two or more different materials in order to gain the desired combination of properties. For example, bag walls have been constructed of an inner film layer of ethylene vinyl acetate copolymer overlaid by an outer film laminate of metallized polyester adhesively bonded between low density polyethylene and ethylene vinyl acetate copolymer layers. Nylon film has replaced the metallized polyester in some structures. Aluminium foil and polyolefins co-extrusion coated with polyvinylidene chloride are further alternatives.

A class of materials developed and sold by BXL Plastics Limited under the Trade Mark HY-BAR and generally comprising multi-layer co-extruded laminated structures have been advantageously employed. These laminates generally comprise a central barrier layer of an ethylene vinyl alcohol polymer (i.e. hydrolysed ethylene vinyl acetate compolymer) bonded to polyolefin layers on each side via adhesive layers.

The polyolefin layers, however, may be replaced in such structures by layers of any thermoplastic.

The bond between the thermoplastic layers and the central layers may be a direct heat bond but is preferably via an adhesive layer which in the case of polyolefin layers such as branched or linear low density polyethylene layers advantageously comprises a modified polyolefin resin such as that sold under the Trade Name Admer or such as that sold under the Trade Name Novatek. These materials may also be advantageously considered for use for the walls of the bags of the present invention amongst the considerable variety of alternatives.

However, as described and claimed in our British Patent Application 8418863, it is particularly preferred that, when the outer casing of the container of the present invention is of generally cylindrical or barrel shape, the walls of the bag comprise a laminate of an ethylene vinyl alcohol polymer layer as hereinbefore defined bonded between thermoplastic layers of different material or materials.

Where the containers of this invention are intended for wine, beer and similar beverages, it is preferred that the bag surfaces contacted by the beverage comprise an ethylene vinyl acetate copolymer (having from 6 to 8% by weight vinyl acetate units) or a linear low density polyethylene.

The bag may be produced by any conventional technique such as welding or blowing techniques or any combination of such techniques. If the wall of the bag is to include a film lining, this may be interposed prior to seam welding of superimposed layers of the material for the main walls. While it is preferred that the main body of a lining film layer is not bonded to the main walls, the lining film is preferably such as to in use gain support from the main walls sufficient satisfactorily to resist the internal gas pressure against undesirable influences.

In any event a lining film layer may be bonded to the main walls in relatively small areas. The bag of this invention may be adapted to receive in sealing engagement an assembly comprising a gas supply device, liquid delivery tube and tap or outlet valve by the attachment or incorporation of a suitable adaptor to which the assembly may be readily secured.

Such adaptor provides for communication with the inside of the bag and for example may comprise a tubular sleeve or gland which may be welded to the bag in known manner. Such a sleeve or other adaptor is preferably threaded externally or otherwise designed to permit a sealing cap to be fitted after filling of the bag and which sealing cap may be replaced by a threaded nut or other appropriate fitting on the dispensing assembly whereby the latter may be sealingly engaged with the bag via the adaptor. Other forms of adaptor and modes of fitting will readily suggest themselves to the skilled addressee as will other forms of temporary sealing cap.

Clearly special features might be incorporated in the adaptor. For example, a sleeve might be constructed in collapsed concertina-like fashion, being extendable by application of pressure within the bag. Such a device may be employed to permit the adaptor and if desired also an attached dispensing assembly, before activation, to be packaged within the confines of the outer casing for protection during transit. Suitable bag dimensioning may likewise accommodate such protective packaging but depending on the material of the bag a greater risk to the integrity of the bag may result and therefore it is preferred to employ the special adaptor in such cases.

With a view to assisting the sealing engagement of the dispensing assembly with the bag and give the dispensing assembly a degree of rigidity, the adaptor may be integral with our firmly attached to or interlocked with the outer casing of the container.

When a sealing cap is employed this may form part of the adaptor if a portion, for example a central portion is removable or piercable. In the latter case the piercable portion may comprise the material of the bag wall which when pierced will allow the delivery tube to pass into the bag. The cap may also be provided with a fitting of bayonet or other type to permit quick attachment of the assembly via a complementary fitting and appropriate seals.

The adaptor is preferably arranged to be located at the top of the container when in its position for use with the dispensing assembly.

The outer casing of the container of the invention may comprise any suitably constructed housing to accommodate the bag and to give it the necessary support during transit and in use with the dispensing assembly, to maintain the integrity of the container and provide necessary access to the bag adaptor and to the dispensing assembly when fitted.

Bearing in mind the need to reconcile the physical requirements of the bag with those of the outer casing and vice versa, the outer casing may be any practical shape. Thus it may be in the shape of a parallel-piped, pyramid or sphere for example but it is preferably of round cylindrical shape. This latter shape combines the advantages of curved surfaces for efficient pressure restraint with ease of construction and assembly of the container.

The material selected for the outer casing is determined primarily by its physical requirements in relation to the casing design and may be of any material such as wood, plastic, cardboard for example and, where combustibility is not a requirement, metal.

The method of manufacture of the outer casing will be determined largely by the material selected.

However, when the casing is of cylindrical shape the main body is conveniently cut from extruded tubular lengths of plastic or other material. The wall thickness of the tube will be selected to have suitable strength in use but may be sufficiently thin to permit collapsing before or after cutting. Where it is desired to incorporate one or both integrally moulded ends, the casing body may be blow moulded for example.

Open ends of a casing body may be closed off to complete the outer casing by closures of moulded plastic or of other material and secured by any means such as welding, tacking, screwing or by bayonet or other fitting.

Access to the bag adaptor and to the dispensing assembly may be provided by a hole made in the outer casing through which the adaptor may protrude. When the adaptor with or without the dispensing assembly is initially packaged within the outer casing a perforated knock-out portion of the outer casing may be provided to give access to and the means for suitable relocation of the adaptor.

Insertion of the bag into the outer casing may be before the casing is completed, for example before applying an end closure or alternatively, by inserting the folded bag through an adaptor access hole.

When the bag is blow moulded it may be blow moulded insitu using the casing as a blow moulding tool. In such a case it may be convenient to mould the adaptor integrally with the bag in the same process.

When the bag is inserted prior to completion of the outer casing it may be filled beforehand provided the bag alone has sufficient strength. However, when the bag is filled with pre-aerated or carbonated liquid for example it is preferably done within the outer casing and with provision being made for controlling the volume increase of the bag during the operation to prevent frothing. To this end the space between the bag and the outer casing may be pressurised in controlled fashion or if the outer casing is perforated or otherwise readily gas permeable, gas pressure may be applied externally of the container and controlled to the same effect.

However, one of the advantages of the present invention is that the liquid to be dispensed in aerated or carbonated condition may be introduced into the bag in the filling operation, in the non-gasified state whereby the above-mentioned problem of frothing is obviated. Subsequently, in using the container of this invention, gas pressurization of the surface of the liquid with a gas which is dissolved under such pressure results in gasification, for example aeration or carbonation, of the liquid.

The dispensing assembly for which the bag of this invention is adapted comprises in combination a gas supply device, a liquid delivery tube and a tap or outlet valve.

The gas supply device may be any means by which pressurised gas may be supplied to the surface of the liquid in the container of this invention when the dispensing assembly is sealingly engaged with the bag. Conveniently, particularly for personally portable containers for domestic use, the device comprises a holder for a compressed gas cylinder or capsule in combination with gas release means such as is commonly employed in known domestic soda siphon chargers.

The gas supply device should be such as to direct the gas under pressure to the surface of the liquid in the container. While this may be done via the liquid, with the use of suitable conduit, through which the gas may be allowed to bubble and initially saturate, it is preferred that the gas under pressure is directly supplied to the surface of the liquid.

Preferably, the gas is supplied via a needle valve or similar device which serves to control the gas flow such as to maintain the pressure in the space above the surface of the liquid substantially constant.

It is preferred that the gas supply to the surface of the liquid is permanently connected during dispensing of the contents of the container subject to any intermittent interruption as a result of pressure control.

The liquid delivery tube and the tap or liquid outlet valve are connected to one another, the delivery tube being of such length that in use it dips into the liquid whereby on opening the tap or valve, the gas pressure above the liquid surface causes the liquid to be forced up the tube and through the tap or valve. The delivery tube which may be made of metal or plastic for example will normally extend substantially to the bottom of the container so that given sufficient gas under pressure the container may be substantially drained. The bottom of the delivery tube may incorporate a filter or other means to avoid delivery of any sediment.

The invention will now be further described with reference to the following drawings in which: Figure 1 illustrates one embodiment of the container of the present invention.

Figure2 illustrates the embodiment shown in Figure 1 wherein a dispensing assembly has been sealingly engaged with the bag.

In Figures 1 and 2 identical components are correspondingly numbered.

In Figures 1 and 2 which are largely diagramatic, 1 indicates generally a container of this invention comprising an outer casing 2 of round cylindrical shape closed off at its ends by end closures 3 and 4.

The outer casing holds an inner flexible bag 5 to which is welded tubular adaptor sleeve 6 via annular weld 7. The adaptor passes through a hole in end closure 4 which is of diameter substantially matching that of the main body of the sleeve but which is resiliently expandable by means of radial slots (not shown) cut around it periphery. In this way the hole permits an annular rib 8a on the surface of sleeve 6 to be forced through whereby the sleeve becomes axially interlocked with the end closure.At least one longitudinal rib 8b (shown in dotted line) provided on the surface of the sleeve is dimensioned so as to fit at least one of the slots whereby the sleeve becomes also interlocked with the end closure in a manner preventing relative rotation. 9 is a screw threaded closure for the bag and is screwed onto the adaptor sleeve when the dispensing assembly indicated generally by 10 in Figure 2 is not in position, as in Figure 1.

The dispensing assembly 10 shown in Figure 2 comprises housing 11 for a compressed gas cylinder or capsule (not shown) and housing extension 12 containing a hollow needle (not shown) for penetration of a seal in the cylinder or capsule and transmission of released gas via a pressure control valve (not shown) to the adaptor sleeve 6 and thereby into the top of the bag 5. The dispensing assembly 10 also comprises delivery tube 15 and tap 16, shown partly in broken line for clarity, connected through body 14 of the assembly by which the latter is connected via a sealing washer (not shown) to the adaptor sleeve 6 with the aid of screw fitting 13 acting on a flange (not shown) on the base of body 14.

To exemplify further the present invention but in no way intending to limit the scope thereof: Outer casing 2 may comprise a section of extruded high density polyethylene tubing of 1 mm wall thickness and internal volume of approximately 5 litres closed off initially at one end only by an injection moulded end closure 3 of similar material and 1.5 mm thickness, having an integral lip riveted to the tubing.

Bag 5 may be of welded cylindrical construction of dimensions matching those of the inside of the outer casing 2, the walls comprising for example an ethylene vinyl alcohol polymer layer coextruded in laminated form between layers of linear low density polyolefin. During construction of the bag the adaptor sleeve 6 which may be of moulded high density polyethylene may be inserted through an aperture made in an end wall of the bag 5 and welded thereto.

The bag 5 may then be inserted into the incomplete casing 2 which is then completed by applying and securing end closure 4 moulded similarly to closure 3 but with an aperture through which the adaptor is passed and by means of which the adaptor may be interlocked with end closure 4 as earlier described.

Conveniently, the bag may then be filled with the liquid to be subsequently dispensed such as a completely fermented beer for example. The closure 9 is then applied.

The container of this invention duly filled may then be conveniently transported to its destination whereupon removal of closure 9 permits the dispensing assembly to be attached. A gas capsule containing carbon dioxide may then be inserted into housing 11 and the seal penetrated with release of gas which enters the space above the liquid via the pressure control valve. The liquid may dissolve some of the gas delaying pressure build up in the space above the liquid and cessation of gas flow through the action of back pressure acting on the pressure control valve.

The container of the present invention is then ready for dispensing its contents via the dispensing assembly.

When the container is empty and the gas stopped by for example manual closure of the pressure control valve the dispensing assembly may be removed for re-use with a fresh container.

Claims (20)

1. A liquid container of the type comprising an inner flexible bag or pouch for containing the liquid and supported by an outer relatively rigid casing characterised in that the bag or pouch is adapted to receive in sealing engagement a dispensing assembly comprising a gas supply device, liquid delivery tube and tap or outlet valve such that in use the surface of liquid contained in said bag or pouch may be pressurised and/or a pressure above said surface maintained by said gas to cause the liquid to be dispensed via the delivery tube on opening the tap or valve and in that the outer casing is constructed to restrain the bag or pouch against over-inflation and to thereby maintain the integrity of the container in use.

2. A liquid container as claimed in claim 1 wherein the bag or pouch is substantially impermeable to the pressurising gas.

3. A liquid container as claimed in claim 2 wherein the bag or pouch is substantially impermeable to carbon dioxide.

4. A liquid container is claimed in either of claims 2 and 3 wherein the bag or pouch is substantially impermeable to atmospheric oxygen.

5. A liquid container as claimed in any one of the previous claims wherein the material of the bag or pouch comprises ethylene vinyl alcohol and polyolefin layers.

6. A liquid container as claimed in any one of the previous claims wherein the bag or pouch surface to contact the liquid comprises an ethylene vinyl acetate copolymer or a linear low density polyethylene.

7. A liquid container as claimed in any one of the previous claims wherein the wall of the bag or pouch includes a lining film.

8. A liquid container as claimed in claimed 1 wherein the bag or pouch is adapted by the attachment or incorporation of an adaptor.

9. A liquid container as claimed in claim 8 wherein the adaptor is a sleeve.

10. A liquid container as claimed in claim 9 wherein the sleeve is welded to the bag or pouch by an annular weld.

11. A liquid container as claimed in claim 8 wherein the adaptor is integral with or firmly attached to or interlocked with the outer casing.

12. A liquid container as claimed in any one of the-previous claims wherein the outer casing is cylindrical in shape.

13. A liquid container as claimed in any one of the previous claims with the bag or pouch of which a dispensing assembly comprising a gas supply device liquid delivery tube and tap or outlet valve is sealingly engaged.

14. A liquid container as claimed in claim 13 wherein the gas supply device includes a holder for a compressed gas cylinder or capsule in combination with gas release means.

15. A liquid container as claimed in claim 4 wherein the compressed gas cylinder or capsule contains carbon dioxide.

16. A liquid container as claimed in any one of claims 13, 14 and 15wherein the gas supply device includes a pressure control valve.

17. A liquid container as claimed in any one of the previous claims containing a beverage.

18. A liquid container as claimed in claim 17 wherein the beverage is carbonated.

19. A liquid container as claimed in any one of the previous claims which is personally portable.

20. A bag or pouch adapted to receive in sealing engagement a dispensing assembly comprising a gas supply device, liquid delivery tube and tap or outlet valve for use in the liquid container as claimed in any one of the previous claims.