GB2282792A

GB2282792A - Liquid container and method of manufacture thereof.

Info

Publication number: GB2282792A
Application number: GB9320981A
Authority: GB
Inventors: William Ronald Stuart Baxter; Lisa Jane Paine
Original assignee: Bass PLC
Current assignee: Bass PLC
Priority date: 1993-10-12
Filing date: 1993-10-12
Publication date: 1995-04-19
Anticipated expiration: 2013-10-12
Also published as: GB2282792B; GB9320981D0

Abstract

A sealed, openable liquid container, e.g., a beverage container 10 having a release tab 30 is partly filled with liquid 24 to leave a headspace 26. An insert 14 is secured to the base of the container 10 by a layer 16 of adhesive or other means. The insert comprises a hollow body 10 having an upwardly directed restricted orifice 20 and containing a sealed gas reservoir 22, which may be in the form of a small sealed balloon filled with air and which, under normal atmospheric pressure, completely fills the hollow body 18. When the can is sealed and pressurised, the pressure causes the reservoir 22 to contract and compress the air therein so that when the release tab 30 is opened, the resultant release in pressure causes liquid within the hollow body 18 to be discharged through the orifice 20 to assist in the formation of a rich creamy foam. The gas reservoir may be in the form of a closed cell foam or defined by a flexible wall or a piston within the insert. <IMAGE>

Description

LIQUID CONTAINER AND METHOD OF MANUFACTURE THEREOF This invention relates to a liquid container which is designed to deliver a liquid, for example, a beverage such as beer, ale, stout or lager, so that a rich creamy foam is formed on top of the liquid by virtue of liquid under pressure which is forced through at least one restricted orifice in an insert in the container so that the discharge of the liquid into the main body of liquid in the container assists in the formation of such rich creamy foam.The present invention is, however, also applicable to other carbonated beverages and noncarbonated liquids (eg soft drinks such as, for example, fruit juices, squashes, colas, lemonades, milk and milk-based drinks, and other alcoholic drinks such as, for example, spirits, liqueurs, wine or wine-based drinks) where it is desired to produce release of a stream of gas bubbles into the liquid on opening of the container. The present invention further relates to a method of manufacturing such a liquid container.

GB-A-1266351 discloses a number of designs of beverage container where a secondary chamber is located in the beverage container and contains gas charged to a pressure substantially above atmospheric pressure. A number of embodiments are described. In one embodiment, the secondary chamber is permanently in communication with the container via the restricted orifice and is charged with gas under pressure at the time of filling of the container. In another embodiment, the secondary chamber is filled with gas and the restricted orifice sealed with gelatine or other non-toxic substance which is intended to retain the gas under pressure within the secondary chamber but which dissolves when in contact with the beverage in the container so as to open the restricted orifice.In a further embodiment, the restricted orifice is provided in a flexible wall of the chamber which is exposed to the pressure in the main body of the container, the arrangement being such that pressure in the main body of the container holds the region of the wall around the restricted orifice sealed against a grommet until the container is opened, whereupon the resultant release of pressure results in the seal being broken and permits the gas under pressure from the secondary chamber to jet into the beverage through the restricted orifice. For a variety of reasons, none of these designs have met with commercial success.

EP-A-0227213 discloses a beverage container wherein, instead of gas being jetted from the secondary chamber by way of a restricted orifice, carbonated beverage or carbonated beverage followed by gas is jetted through the restricted orifice in order to induce fine bubble formation in the main body of the beverage. The secondary chamber may be in the form of a moulded plastics hollow insert which before use is flushed with nitrogen to displace air therefrom which would otherwise cause aerobic spoilage of the beverage. The insert (with the restricted orifice facing downwardly) is then secured in place at the bottom of the container which at this stage is open at the top. The container is partially filled with the carbonated beverage, and then dosed with liquid nitrogen and sealed so that the liquid nitrogen evaporates to pressurise the sealed container.As a result of pressure equalisation, beverage derived from the main body of the container is forced into the insert so as to leave a pressurised headspace above the beverage in the insert. The sealed and pressurised container is then pasteurised, packaged and stored before distribution and sale. The problems with such an insert are that it is difficult to flush with nitrogen to remove sufficient air therefrom and that such flushing cannot be effected at the time of production of the insert itself because of the risk of air leaking back into the insert before it is inserted into the container.

Thus, in practice, the inserts have to be flushed with nitrogen on site immediately before insertion into the containers on the production line.

According to one aspect of the present invention, there is provided a sealed, openable liquid (e.g, beverage) container which is pressurised to a pressure greater than atmospheric pressure and which is partly filled with liquid under pressure so as to leave a headspace; and a hollow insert disposed in the container, said hollow insert having at least one restricted orifice therein providing communication between the interior of the insert and the interior of the container, the interior of the insert being partially filled with liquid, wherein the remainder of the interior of the insert is occupied by a sealed pressurised expandable gas reservoir having a movable wall which separates the gas from the liquid in the insert, and the arrangement being such that when the container is opened, the resultant pressure release causes the gas reservoir to expand so that the movable wall forces liquid from the insert through said at least one restricted orifice.

The pressurised gas reservoir preferably takes the form of a sealed bag having a flexible or elastomeric wall, eg a sealed balloon. However, it is also possible for the sealed gas reservoir to be comprised by a closed cell flexible or elastomeric foam. In such an arrangement, the external surface of the closed cell foam defines the movable wall. Alternatively, the sealed gas reservoir may be formed by an open cell foam of self-skinning flexible or elastomeric material such that the skin is substantially gas impermeable. A further possibility is for the pressurised gas reservoir to be defined by a flexible wall or diaphragm which is sealed with the interior wall of the insert adjacent the restricted orifice.A still further possibility is for the movable wall to be defined by (a) a piston sealingly slidable in the insert or (b) an end wall of a bellows element whose interior may either define the gas reservoir or may define the volume which is occupied in use by the liquid which has entered the insert. In all cases, it is especially preferred for the gas reservoir to be of a size and shape that it occupies substantially the whole of the interior of the insert at normal atmospheric pressure but which can contract under applied pressure to admit liquid into the insert and to pressurise the gas.

The restricted orifice may be located in the insert so that it faces the top or a side wall of the container, the insert being disposed at or adjacent the bottom of the container.

The insert may be secured to the bottom or side wall of the container by a suitable adhesive, for example a hot melt adhesive. Alternatively, a mechanical fastening such as a ring or leg(s) which is/are braced against or an interference fit with the wall of the container may be employed.

It is to be appreciated that, with the liquid container according to the present invention, the design of the gas reservoir and insert is such that, at normal atmospheric pressure, the gas reservoir substantially completely fills the interior of the insert. Thus, it is possible for the insert to be manufactured complete with the gas reservoir away from the packaging line, and there is no need to flush the insert with nitrogen or other inert gas immediately before use. The gas within the gas reservoir is conveniently air since it always remains separated from the liquid in use and therefore there is no risk of aerobic spoilage of the liquid. Thus, the use of an insert which contains a headspace above the liquid in the insert, as taught in EP-A-0227213, is completely avoided.

According to a second aspect of the present invention, there is provided an insert constructed and adapted to form part of a sealed, openable liquid container according to said one aspect of the present invention, said insert having a restricted orifice therein providing communication between the interior of the insert and exterior, the interior of the insert being substantially completely filled by a contractable sealed gas reservoir having a movable wall which separates the gas in the reservoir from the restricted orifice and which in use moves to admit liquid into the insert through the restricted orifice.

According to a third aspect of the present invention, there is provided a method of manufacturing a sealed, openable liquid container, comprising the steps of securing an insert according to said second aspect of the present invention into a container, partly filling the container with liquid, and sealing and pressurising the container so that liquid from the container passes through the restricted orifice in said insert and into the interior of the latter whereby to move the movable wall of the sealed gas reservoir therein so as to pressure said gas such that, when the liquid container is opened, the pressure drop within the container results in liquid in the insert being ejected into the main body of liquid in the container by virtue of the force exerted thereon by the pressurised gas via the movable wall.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side elevation showing a liquid container according to the present invention as applied to a beverage, the container being illustrated in a condition in which it has been partly filled with beverage but before seaming a top thereon and pressurising; Figure 2 is an axial section showing the beverage container after sealing, pressurisation and pasteurisation; Figure 3 is an axial section showing the beverage container immediately upon opening thereof; and Figures 5 and 6 are axial sections through alternative forms of insert according to the present invention.

Referring now to Figure 1 of the drawings, the beverage container 10 is shown in a partly compieted condition with an open top 12. In this embodiment, the container 10 has an insert 14 secured to its base by a layer 1 6 of an adhesive such as a hot melt adhesive. The insert 14 comprises a hollow body 18 which in this embodiment is formed of polypropylene, but which may be formed of a suitable lacquered aluminium or aluminium alloy. The hollow body 18 has an upwardly directly restricted orifice 20 therein providing communication between the interior of the hollow body 18 and the interior of the container 10. The restricted orifice 20 is disposed on the upper side of the hollow body 18, ie that side which faces away from the base of the container 10.The hollow body 18 contains a sealed gas reservoir 22 in the form of a small sealed balloon which is filled with air so that, at this stage when the insert is at normal atmospheric pressure, the reservoir 22 occupies substantially the whole of the interior of the hollow body 18.

The container 10 is partly filled with carbonated beverage 24, e.g. beer, ale, lager or stout, so as to leave a headspace 26. The headspace 26 is then dosed with a small quantity of liquid nitrogen sufficient to flush air from the headspace 26 and to provide the necessary pressurisation of the beverage container 10 after it has been sealed by seaming a top 28 thereto in a manner which is very well known in the art. In this condition, the restricted orifice 20 always remains submerged in the beverage 24 in the container 10. Thus, upon pressurisation of the container, beverage under pressure is forced through the restricted orifice 20 and into the interior of the insert 14. This causes the gas in the reservoir 22 to be compressed to the condition illustrated in Figure 2 until pressure equalisation occurs.It will be appreciated, however, that in accordance with normal canning procedure, the beverage container after seaming is inverted and subjected to pasteurisation before being cooled, reinverted, and subsequently packaged before distribution and sale. During pasteurisation, the pressure within the container increases substantially as a result of the elevated temperature of pasteurisation, but is allowed to cool subsequently back to room temperature. During heating and cooling, beverage is able to flow into and out of the insert 14 through the restricted orifice 20 to maintain pressure equalisation.

When the container 10 is opened by operation of release tab 30 on the top 28, the pressure within the container 10 is immediately released thereby causing a substantial pressure difference to occur across the restricted orifice 20. This pressure difference results in carbonated beverage being jetted from the insert 14 through the restricted orifice 20 under the action of the pressurised gas in the reservoir 22, the result being to promote the formation of a swirl of bubbles upon dispensing of the beverage into a glass and the formation of a rich creamy head thereon.

With the aboveRescribed insert, there is no need to flush the interior of the insert with nitrogen to displace air therefrom before the insert is used because the gas reservoir 22 substantially completely fills the insert 14. Thus, the insert 14 with gas reservoir 22 can be manufactured at any convenient stage and can therefore be conveniently and simply handled prior to and on the canning line.

In the alternative embodiment illustrated in Figure 4, the body 18 of the insert 14 is formed of top and bottom body parts 1 8a and 1 8b which are secured together so as to seal elastomeric wall 22a across the top of body part 1 8b whereby the interior of the body part 1 8b together with the wall 22a defines the gas reservoir 22 which is sealed from the restricted orifice 20 provided in the body part 1 8a and which occupies the whole of the interior of the insert 14 at normal atmospheric pressure. During the canning operation, beverage from the container 10 is forced under pressure through the restricted orifice 20 and deforms the flexible wall 22a inwardly so that bevrage is admitted and so as to pressurise the gas in the reservoir 22. In the condition illustrated in Figure 4, the flexible wall 22a is shown in a position corresponding to an early stage of beverage admission into the insert 14. In its fully unpressurised condition before use, the flexible wall 22a lies closely against the underside of the body part 1 8a so as to exclude air completely from the interior of the insert 14 externally of the gas reservoir 22.

In the embodiment of Figure 5, the reservoir 22 is constituted by a closed cell elastomeric foam which is shaped so as to fill totally the interior of the insert 14. Pressurisation of the insert 14 with beverage causes the foam to be compressed elastically.

Claims

1. A sealed, openable liquid container which is pressurised to a pressure greater than atmospheric pressure and which is partly filled with liquid under pressure so as to leave a headspace; and a hollow insert disposed in the container, said hollow insert having at least one restricted orifice therein providing communication between the interior of the insert and the interior of the container, the interior of the insert being partially filled with liquid, wherein the remainder of the interior of the insert is occupied by a sealed pressurised expandable gas reservoir having a movable wall which separates the gas from the liquid in the insert, and the arrangement being such that when the container is opened, the resultant pressure release causes the gas reservoir to expand so that the movable wall forces liquid from the insert through said at least one restricted orifice.

2. A container as claimed in claim 1, wherein the pressurised gas reservoir takes the form of a sealed bag having a flexible or elastomeric wall.

3. A container as claimed in claim 2, wherein the sealed bag is a sealed balloon.

4. A container as claimed in claim 1, wherein the reservoir is comprised by a closed cell flexible or elastomeric foam, the external surface of the closed cell foam defining the movable wall.

5. A container as claimed in claim 1, wherein the reservoir is formed by an open cell foam of self-skinning flexible or elastomeric material such that the skin is substantially gas impermeable.

6. A container as claimed in claim 1, wherein the pressurised gas reservoir is defined by a flexible wall or diaphragm which is sealed with the interior wall of the insert adjacent the restricted orifice.

7. A container as claimed in claim 1, wherein the movable wall is defined by (a) a piston sealingly slidable in the insert or (b) an end wall of a bellows element whose interior either defines the gas reservoir or defines the volume which is occupied in use by the liquid which has entered the insert.

8. A container as claimed in any preceding claim, wherein the gas reservoir is of a size and shape such that it occupies substantially the whole of the interior of the insert at normal atmospheric pressure but which can contract under applied pressure to admit liquid into the insert and to pressurise the gas.

9. A container as claimed in any preceding claim, wherein the restricted orifice is located in the insert so that it faces the top or a side wall of the container, the insert being disposed at or adjacent the bottom of the container.

1 0. An insert constructed and adapted to form part of a sealed, openable liquid container as claimed in claim 1, said insert having a restricted orifice therein providing communication between the interior of the insert and exterior, the interior of the insert being substantially completely filled by a contractable sealed gas reservoir having a movable wail which separates the gas in the reservoir from the restricted orifice and which in use moves to admit liquid into the insert through the restricted orifice.

1 1. A method of manufacturing a sealed, openable liquid container, comprising the steps of securing an insert as claimed in claim 10 into a container, partly filling the container with liquid, and sealing and pressurising the container so that liquid from the container passes through the restricted orifice in said insert and into the interior of the latter whereby to move the movable wall of the sealed gas reservoir therein so as to pressure said gas such that, when the liquid container is opened, the pressure drop within the container results in liquid in the insert being ejected into the main body of liquid in the container by virtue of the force exerted thereon by the pressurised gas via the movable wall.

12. A container as claimed in claim 1, substantially as hereinbefore described with reference to Figs 1 to 3, or Fig 4 or Fig 5 of the accompanying drawings.

13. An insert as claimed in claim 10, substantially as hereinbefore described with reference to Figs 1 to 3, or Fig 4 or Fig 5 of the accompanying drawings.

14. A method as claimed in claim 11, substantially as hereinbefore described with reference to Figs 1 to 3, or Fig 4 or Fig 5 of the accompanying drawings.

15. A sealed, openable liquid container when manufactured by a method as claimed in claim 11 or 14.