Container for pressurised liquid

Abstract

 A flexible bag (10) adapted for reception of a pressurised liquid, e.g. a carbonated beverage, and having a tap (15) whereby the liquid may be dispensed is enclosed within a cylindrical casing (11) at each end of which is a respective end cap (12, 13). To minimise head space in the bag (10) as the liquid is dispensed so that the liquid does not go flat or stale, one end cap (13) is movable inwardly of the casing (11). This is preferably achieved by pushing downwards on the end cap (13).

Description

[0001] This invention relates to a container for pressurised liquid, particularly but not exclusively a carbonated beverage such as beer or sparkling wine or a soft drink.

[0002] So-called bag-in-box containers are already well known for still table wine. Such containers consist of a substantially impermeable bag, usually of metalised polyester, disposed within a box of cardboard or similar material, the bag being filled with wine and having a tap projecting through the box material so that the wine can be easily dispensed. The great advantage of such a container over a conventional bottle, carafe or the like is that the bag is made of flexible material so that as liquid is dispensed the bag collapses by a corresponding amount and virtually no air is allowed to enter to cause oxidation of the liquid. Progressive oxidation of a beverage such as wine leads, of course, to the beverage firstly becoming stale and subsequently spoiled. Accordingly the bag-in-box packaging keeps the product fresh for an extended period.

[0003] A further advantage of bag-in-box containers is that they are lighter than most conventional containers and are therefore more suitable for transporting liquids and/or for holding larger quantities of liquid. Moreover, they are inexpensive enough to be sold as disposable containers.

[0004] The integral tap is also particularly convenient for dispensing the contained liquid and there is no difficulty in the consumer opening the container, as may be the case with bottles or cans.

[0005] It is desirable to extend bag-in-box packaging to pressurised liquids, particularly carbonated beverages such as beer, sparkling wine and soft drinks, so as to achieve, in relation to these liquids, the above-mentioned advantages. However, when such liquids are filled into flexible bags within semi-rigid casings in the form of boxes, the latter have been found to sag or bulge outwardly because of the additional pressure of gas from the liquid. This is clearly unsatisfactorily as it makes the overall container unstable and likely to topple over and it is not possible to stack the containers for storage or transportation.

[0006] A further problem in relation to carbonated beverages is that when there is a space above a quantity of the liquid (a so-called "head space") carbon dioxide tends to come out of the liquid into the space and the liquid becomes increasingly flat. This will tend to occur when a bag of the aforementioned type is only partially filled with liquid, (e.g. when a portion of the original volume has been dispensed) since the bag, being flexible, can be forced outwards as far as the walls of the box by gas coming out of the liquid.

[0007] An object of the present invention is to provide a container based on the bag-in-box principle of a flexible bag within an outer casing, which container will not sag or bulge outwardly when filled with a pressurized liquid and which also has means to minimize the head space above such liquid.

[0008] With this object in view, the present invention provides a container for pressurized liquid comprising a flexible bag adapted for reception of liquid and having a tap whereby the liquid may be dispensed, the bag being enclosed within a casing of plastics or paperboard through which the tap projects, characterised in that the casing is in the form of a cylinder with a respective end cap arranged at each end, at least one end cap being movable from an initial position adjacent its end of the cylinder towards the other end cap.

[0009] The cylindrical shape is better than any other at resisting sagging or bulging due to pressure of liquid.

[0010] The most convenient construction of container has been found to include only one movable end cap. The other end cap is firmly fixed in position and the tap projects through the casing adjacent to the fixed end cap. In some instances, however, the tap could project through the fixed end cap.

[0011] The movement of the other end cap may be brought about in one of three ways.

[0012] Firstly, the movable end cap may be part-spherical in form so as to present a concave outer face and a convex inner face. Such a cap must be made of resilient material, such as rigid or flexible plastics. Because of its shape and resilience it may be capable of simply being pushed inwardly from its end of the casing while maintaining a tight fit within the casing when force is not applied to its concave outer face. However, in practise it has been found preferable to provide means for application of force to the convex inner face of the movable end cap to ensure that said cap maintains a tight fit in the cylinder when it is not being pushed inwardly. Said means preferably comprises an auxiliary plate of resilient material located inside the movable end cap, the plate being screw-threadedly connected to a handle outside the end cap by way of an aperture in said end cap such that tightening of the screw-threaded connection causes application of force to the convex inner face of the movable end cap.

[0013] Alternatively, the cylinder may be internally screw-threaded while the movable end cap has an externally screw threaded rim so that it can be screwed inward ly from its end of the casing either manually by means of a hand grip on its outer face or by means of addition al machinery. From a practical point of view, this is not as favourable as the above-mentioned arrangement due to the difficulty of providing an internal screwthread in the cylinder.

[0014] Finally, a number of ratchet devices may be provided on the internal surface of the cylinder and the movable end cap, which in this case is not part-spherical, may be pushed inwardly of the cylinder in engagement with these devices.

[0015] In all the above-mentioned methods of achieving movement of the end cap force may be applied manually or mechanically. It will, of course, be understood that in practise the end cap is intended to be moved inwardly of the casing when a volume of liquid has been dispensed from the bag so as to minimize the head space in the bag and prevent gas escaping from the pressurized liquid. The end cap should therefore be moved inwardly until further movement is prevented by counterpressure from the liquid in the bag.

[0016] A number of protrusions are preferably provided around the inner surface of the cylinder outside the movable end cap to prevent removal of the end cap from the casing when the,pressure of the liquid inside the bag increases, e.g. in hot weather.

[0017] The fixed end cap, which is generally circular or part-spherical in shape with a rim directed outwardly of the casing, may be fixed in position in any one of a variety of manners which may be found most suitable in any particular circumstances. For example, it may be glued in position, or form an interference fit in the end of the cylinder or be held by catch means such as beading or lugs on the end cap or on the internal surface of the cylinder. Advantageously, however, this end cap has a turned over rim providing a circumferential slot into which the end of the cylinder fits.

[0018] The base of the tap or an outlet member connecting the tap to the bag conveniently engages in a slot provided in the cylinder adjacent to the fixed end cap, or provided in the fixed end cap itself, so that the bag is correctly positioned within the casing. This also ensures that the tap is held securely in an appropriate dispensing position.

[0019] The bag is preferably formed of two layers of material, namely an inner layer of polyethylene and an outer covering of nylon/aluminium/polyethylene laminate. The latter material has been found to be particularly effective in preventing escape of carbon dioxide from carbonated liquids within the bag, and preventing the ingress of oxygen into the bag.

[0020] In embodiments where the tap projects through the end cap and the container is intended to be laid on its side when liquid is dispensed therefrom, anti- roll means, such.as longitudinal ribs, are advantageously provided on the outer surface of the cylindrical casing.

[0021] The invention will be described further, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is an exploded perspective view of a preferred practical embodiment of the container of the invention;

Fig. 2 is a vertical cross-section of the same embodiment to a somewhat larger scale;

Fig. 3 is a fragmentary cross- section of one end of a slightly modified embodiment of the container of the invention;

Fig. 4 is a fragmentary cross-section of one end of another embodiment of the container of the invention; and

Fig. 5 is a side view, to a reduced scale, of a container in accordance with the invention in which the tap projects through a fixed end cap.

[0022] In carrying out a first practical embodiment of the invention, as shown in Figs. 1 and 2, a flexible bag 10 is located within a casing in the form of a paperboard cylinder 11 having respective end caps 12, 13. The bag is formed of two inner sheets of linear low density polyethylene and two outer sheets of nylon/aluminium/low density polyethylene laminate bonded together adjacent their periphery. The bag also has a short cylindrical outlet member 14 with annular ridges and a tap 15 which fits into the outlet member 14.

[0023] The outlet member 14 fits into a slot 16 (Fig. 1) at one end of the cylinder 11 so that the tap 15 is positioned outside the cylinder 11 while the bag 10 remains inside the cylinder 11.

[0024] Each end cap 12, 13 is made of resilient plastics material and is part spherical in shape, having a convex inner face 12a,13a and a concave outer face 12b, 13b with a rim 22, 23 respectively directed outwardly of the casing towards the respective end of the cylinder 11.

[0025] One end cap 12 (hereinafter referred to as "the first end cap") fixed firmly and immovably onto the cylinder 11. Its rim 22 is turned over, as shown in Fig. 1, to provide a circumferential slot 17 into which the end of the cylinder 11 fits and in which it is secured by means of rivets 18. On its outer conuave face 12b, the first end cap 12 has a number of cross-walls 19 extending between points on the rim 22. These cross-walls 19 serve to strengthen the first end cap 12. The rim 22 is specially formed with a recess 24 in a raised portion to support the outlet member 14 of the tap 15 and the slot 17 is blocked in this region to further support the tap 15 and strengthen the cylinder 11.

[0026] The other end cap 13 (hereinafter referred to as "the second end cap") is movable from an initial position adjacent its end of the cylinder 11 towards the first end cap_.12. The second end cap 13 has shallow radial cross-walls 25 and a central aperture 26. Its rim 23 is cylindrical and is a friction fit inside the paperboard cylinder 11. An auxiliary plate 20 also of resilient plastics material and having a convex inner face and a concave outer face is located in the cylinder 11 just inside the second end cap 13. It has four radial slots 27 for enhanced flexibility and a central internally screw threaded bush 28 which projects into the aperture 26 of the second end cap 13.

[0027] A T-shaped handle 30 is connected to the auxiliary plate 20 by way of the aperture 26 by means of a screw threaded shaft 29 which engages the bush 28.

[0028] In use, with the bag 10 filled with a suitable liquid such as beer, the second end cap 13 will be in positioned closely adjacent the end of the cylinder 11 and the handle 30 will be screwed into the bush 28 as far as possible. This means that the auxiliary plate 20 will be pressed against and apply a force to the convex face 13a of the second end cap 13. The end cap 13 is thus slightly flattened and sufficiently expanded in diameter to make its rim 23 an extremely tight fit in the cylinder 11. In this condition the second end cap 13 cannot be pushed inwardly of the cylinder 11.

[0029] The container can conveniently be carried by means of the handle 30 and when set down on an appropriate surface the beer can be dispensed simply by turning the tap 15. When a certain portion of the initial volume of beer has been dispensed and the remaining beer is to be kept for some time, e.g. for the next day or a few days hence, the user turns the handle 30 to loosen its screw-threaded engagement with the auxiliary plate 20 and thus decrease the pressure of the auxiliary plate 20 against the inner face 13a of the end cap 13. The user can then push the second end cap 13 downwards and into the cylinder 11 as far as possible, that is to say until the counter-pressure of the remaining liquid prevents its further movement. At this point the head space in the bag will be at a minimum and the beer will remain fresh and its tendancy to go flat will be minimised. The handle 30 is then turned in the opposite direction so that the auxiliary plate 2o again presses firmly against the inner face 13a of the second end cap 13 and ensures that the end cap 13 is a tight fit in the cylinder 11.

[0030] Due to its special part-spherical shape and the presence of the auxiliary plate 20, the second end cap 13 does not readily move outwardly of the cylinder 11 away from the first end cap 12 even when considerable - outward force is applied to the handle 30. Nevertheless, there may be a tendancy for the second end cap 13 to move outwards when the temperature is high and the pressure of liquid in the bag 10 is increased. To prevent removal of the second end cap 13 from the cylinder 11 in this way, protrusions may be provided around the inner surface of the cylinder adjacent the outer face 13b of the second end cap 13. Fig. 3 shows a modification in which a number of rivets 31 are positioned around the cylinder 11 adjacent its end to provide such protrusions. A number of recesses 32 are provided around the rim 23 of the end cap 13 to accommodate the rivet shafts in the initial position of the end cap 13.

[0031] In a second embodiment of the container of the invention, as illustrated in Fig. 4, the cylinder 11 is formed of plastics material and is screw-threaded on its internal surface, as indicated at 41. The end caps are circular in shape with rims directed towards their respective ends of the cylinder. The first end cap (not shown) is fitted firmly and immovably into the cylinder 11 by an interference fit or by lugs on the outside of the rim engaging with corresponding L-shaped recesses formed on the internal surface ol the cylinder. The second end cap 43 has a cross wall or flange 44 extending across its outer face between appropriate locations on the inside of the rim 42. The outer surface of the rim 42 is screw-threaded and engages with the internal threading of the cylinder 11. The cross wall or flange 44 serves as a hard grip whereby the second end cap 43 can be turned and moved inwards or outwards of the cylinder 11.

[0032] A flexible plastics handle (not shown) in the form of a strip extending between opposing points on the outside of the cylinder or formed integrally with either the first or second end caps may be provided for carrying this container.

[0033] In a further embodiment, which is not illustrated and is probably not of much practical significance, a number of ratchet devices may be provided on the internal surface of the cylinder, one of the end caps being movable inwardly of the cylinder in engagement with said devices.

[0034] The foregoing are, of course, illustrative and not limitative of the scope of the invention and many variations are possible. For example, in the first described, preferred, embodiment the auxiliary plate need not be part-spherical in shape and its engagement with the handle may be by way of a screw threaded shaft on the plate and an internally screw-threaded bush or the handle, i.e. opposite to the previously described manner of engagement. Moreover, alternative means of selectively pressing the auxiliary plate against the inner face of the movable end cap may be provided.

[0035] The tap has been particularly described as projecting through a slot in the cylinder adjacent the fixed end cap. This is preferred as it allows the cylinder to be placed upright on a surface for dispensing the liquid, usually a beverage. However, the tap may alternatively project through a slot in the fixed end cap, as shown in Fig. 5. In this case, a pair of ribs (not shown) may be provided extending longitudinally, a short distance apart, on the external surface of the cylinder. When the cylinder is disposed horizontally for dispensing of liquid it rests on these ribs which prevent it from rolling.

[0036] Other variations are possible within the scope of the invention. It will, of course, be appreciated that containers in accordance with the invention may be produced in a wide range of sizes to accommodate differing volumes of liquid, for example from considerably less than a litre to tens of litres. Also, for storage and marketing the entire container may be shrink-wrapped with transparent film so that the tap cannot be tampered with prior to sale.

Claims

1. A container for pressurised liquid comprising a flexible bag(10) adapted for reception of liquid and having a tap (15) whereby the liquid may be dispensed, the bag (10) being enclosed within a casing (11) of plastics or paperboard through which the tap (15) projects, characterised in that the casing (11) is in the form of a cylinder with a respective end cap (12, 13) arranged at each end, at least one end cap (13) being movable from an initial position adjacent its end of the cylinder (11) towards the other end cap (12).

2. A container as claimed in claim 1 wherein only one end cap (13) is movable and the end cap (12) is firmly fixed in position, and the tap (15) projects through the casing (11) adjacent to the fexed end cap (12).

3. A container as claimed in claim 2 wherein the movable end cap (13) is formed of resilient material, has a convex inner face and a concave outer face, and is capable of being pushed inwardly from its end of the casing (11).

4. A container as claimed in claim 3 wherein means are provided for application of force to the convex inner face of the movable end cap (13) so that said cap (13) maintains a tight fit in the cylinder (11).

5. A container as claimed in claim 4 wherein said means comprise an auxiliary plate (20) of resilient material located inside the movable end cap (13), the plate (20) being screw-threadedly connected to a handle (30) outside the movable end cap (13) by way of an aperture(26) in said end cap (13) such that tightening of the screw-threaded connection causes application of force to the convex inner face of the movable end cap (13).

6. A container as claimed in claim 2 wherein a number of ratchet devices are provided on the internal surface of the cylinder (11) and the movable end cap (13) is capable of being pushed inwardly from its end of the casing (11) in engagement with these devices.

7. A container as claimed in claim 2 wherein the cylinder (11) is internally screw-threaded (41) and the movable end cap (13) is capable of being screwed inwardly from its end of thecasing (11).

8. A container as claimed in any of claims 2 to 7 wherein a number of protrusions (31) are provided around the inner surface of the cylinder (11) outside the movable end cap (13) to prevent removal of that end cap (13) from the casing.

9. A container as claimed in any of claims 2 to 8. wherein the fixed end cap (12) has a rim (22) directed outwardly of the casing (11), the rim (22) being turned over to provide a circumferential slot (17) into which the end of the cylinder (11) fits.

Drawing