WO1993010021A1

WO1993010021A1 - A pressurised container for providing an effervescent liquid

Info

Publication number: WO1993010021A1
Application number: PCT/GB1992/002111
Authority: WO
Inventors: Bernard Derek Frutin
Original assignee: Scottish And Newcastle Plc
Priority date: 1991-11-14
Filing date: 1992-11-13
Publication date: 1993-05-27
Also published as: JPH07501301A; HUT69086A; HU9401202D0; EP0611359A1; CZ119094A3; AU2916492A; CA2123233A1

Abstract

A method and apparatus for producing a containerised liquid is described. A container (90) is provided with a barrier (92) mounted therein. A gas (97) is introduced into the container (90) prior to the barrier (92) and after the barrier (92), a liquid (96) is introduced. The liquid (96) is pressurised with the gas to a higher than atmospheric pressure. The barrier (92) is permeable to the gas but is substantially impermeable to liquid. When the container is opened by rupturing using the rupturing mechanism (91), the pressure of the liquid (96) closes the atmospheric pressure and gas on the other side of the barrier from the liquid flows through the barrier into the liquid.

Description

"A Pressurised Container for Providing an Effervescent Liquid"

The invention relates to a pressurised container for providing an effervescent liquid in a container and especially, but not exclusively, for releasing a gas such as carbon dioxide or nitrogen into a consumable liquid, such as beer contained in a can.

Traditionally, it has not been possible to reproduce the taste and quality of draught beer in beer contained in a can. One of the problems with achieving this has been the difficulty of releasing a gas, such as nitrogen into canned beer immediately before the beer is served.

In accordance with a first aspect of the present invention, a method of producing a containerised liquid comprises providing a container having a rupturable wall portion, introducing a gas into the container, providing in the container a barrier which is gas- permeable and is substantially impermeable to liquid, introducing a liquid pressurised with gas in the container on the other side of the barrier, and sealing the container. 1 In accordance with a second aspect of the present

2 invention, a pressurised container having a rupturable

3 wall portion comprises a barrier which is gas-permeable

4 and is substantially impermeable to a liquid in the

5 container, the barrier dividing the container into

6 first and second chambers, the barrier permitting

7 passage of a gas in the container between the chambers

8 so that when the wall portion is ruptured to permit one

9 of the chambers to communicate with atmospheric

10 pressure and creates a differential pressure between

11 the chambers, gas in the other chamber flows through

12 the barrier into the one chamber. 13

14 Typically the barrier may comprise a material 5 impermeable to liquid and gas, and having a aperture 6 therein, and a gas permeable material covering the 7 aperture. Typically, the aperture has a diameter of 8 0.010 to 0.015 inches and preferably is approximately 9 0.012 inches. 0 1 Preferably the barrier is fixed in position before the 2 container is filled with liquid. However, 3 alternatively the barrier could be fixed in position 4 after the container is filled with liquid. 5 6 In accordance with a third aspect of the present 7 inventio , a method of producing a container liquid 8 comprises providing a container having a rupturable 9 wall portion, introducing a fluid into the container, 0 providing in the container a barrier which is 1 substantially impermeable to the fluid on one side of 2 the barrier, the barrier having means for selectively 3 allowing passage of the fluid through the barrier, 4 providing a liquid in the container on the other side 5 of the barrier, and sealing the container. Preferably, the means for selectively allowing passing of the fluid is actuable on reduction of the pressure of the liquid in the container. Said means is preferably a valve mechanism.

Preferably, the rupturable wall portion comprises means for opening the container which is typically a mechanism which when operated provides an aperture in the container through which liquid in the container may be expelled. Typically, the mechanism may be, for example, a ring-pull mechanism or other mechanism which enables the liquid to be poured from the container.

In accordance with a fourth aspect of the present invention, a pressurised container having a rupturable wall portion includes a barrier substantially impermeable to a pressurising fluid and a liquid in the container, the barrier dividing the container into first and second chambers and including a pressure operable valve mechanism movable between a closed position and an open position, the valve mechanism allowing passage of the fluid and/or liquid between the chambers when the wall portion is ruptured to permit one of the chambers to communicate with atmospheric pressure to create a differential pressure between the chambers, the valve mechanism preventing such passage when the pressures are equal.

In accordance with a further aspect of the present invention, the fifth aspect defined in the immediately preceding paragraph may have an aperture through the barrier in addition to or instead of the valve mechanism, whereby on pressurising the liquid on one side of the barrier a portion of the liquid passes through the aperture to the other side of the barrier.

In accordance with a sixth aspect of the present invention, a method of producing a containerised liquid comprises introducing a fluid into the container, providing in the container a barrier which is substantially impermeable to the fluid and the liquid, so that the liquid is maintained on one side of the barrier, the barrier having means for selectively allowing passage of the fluid through the barrier, introducing a liquid into the container on the other side of the barrier, pressurising the liquid to displace the barrier to pressurise the fluid, and sealing the container.

Preferably, the fluid comprises a gas which is typically carbon dioxide or nitrogen.

The liquid may be any consumable liquid, for example, water, juice, such as fruit juice. However, preferably the liquid is an alcoholic drink, such as beer.

Typically, the container is of a generally cylindrical shape with one end open prior to receiving the fluid and the liquid. Preferably, in this case, the fluid is pressurised by compressing the fluid between the other end of the container and the barrier. Typically, after the pressurised liquid is introduced into the container, the open end is sealed. Reduction of the pressure of the liquid in the container is achieved by opening the container for example by operating the pull mechanism on the container, which creates a pressure differential between the liquid and the fluid. Preferably, the valve mechanism comprises a valve member which seals an aperture in the barrier and the valve mechanism opens when the pressure on the one side of the barrier exceeds the pressure on the other side.

Typically, the apparatus may include a reservoir portion adjacent the barrier and liquid is expelled from the reservoir into the main body of liquid by flow of the fluid when the valve mechanism is opened.

The valve mechanism may comprise a movable portion of the barrier which typically may be provided by making a portion of the material of the barrier flexible. Preferably, the movable portion is movable between a first position in which the valve mechanism is closed and a second position in which the valve mechanism is open. Typically, the valve mechanism may be opened by rupture of the movable portion of the barrier when the movable portion moves to the second position. Alternatively, the valve mechanism could further include a valve member which seals with the movable portion when the movable portion is in the first position to prevent fluid passing through the valve mechanism but which does not seal with the movable portion when the movable portion moves to the second position, in order to permit fluid to pass through the valve mechanism.

In a further alternative, the valve mechanism may comprise a valve of the "woodcroft¹¹ type and in this case, the valve mechanism may additionally include a device which forms a sleeve over the valve. The sleeve may comprise at least one aperture, such that when the valve mechanism opens, fluid is expelled through the aperture in the valve sleeve. Typically, the aperture in the valve sleeve may have a diameter of 0.010 to 0.015 inches, for example, 0.012 inches.

In a still further alternative, the valve mechanism may comprise a "butterfly¹¹ type valve which has an enlarged head portion, which is movable to seal or open an aperture in the barrier.

The pull mechanism may comprise a device on the top surface of the container so that when it is pulled to rupture the wall portion it is retained on the container. Alternatively, the pull mechanism may comprise a device which is capable of being completely removed from the container.

The apparatus may further have means to retain the barrier in a fixed position after pressurisation of the fluid. Typically, the means to retain the barrier in position may comprise flanges on an edge of the barrier which engage with a side wall of the container so that the barrier may only be moved within the container in a direction to pressurise the fluid and which substantially prevent the pressure of the fluid causing reverse movement of the barrier within the container.

Alternatively, or in addition to flanges on the edge of the barrier, one or more lugs may be provided on the inside wall of the container to engage with and retain the barrier in position within the container.

Alternatively, or in addition the means to retain the barrier in position may be by frictional force between the edge of the barrier and the side wall of the container. The degree of frictional fit of the barrier 1 in the container may be achieved by adjusting the

2 diameter of the barrier and/or providing the barrier

3 with a side wall flange which engages the container

4 inside wall and the frictional force may be chosen by

5 varying the length of the side wall flange. 6

7 Alternatively, the barrier could be fixed in position

8 after filling the container with the liquid by carrying

9 relative movement between the barrier and the

10 container, for example, by heating the content to

11 create a pressure differential to actuate a mechanism

12 on the barrier to lock the barrier in position. This

13 could comprise movable sections on the barrier which

14 are deflected by contact with the base of the container

15 to generate an increase in diameter of the barrier to

16 increase the frictional fit of the barrier in the

17 container. 18

19 Alternatively, heating of the container may actuate an

20 adhesive located in the barrier and/or inside surface

21 of the container to bond the barrier to the inside of

22 the container. 23

24 As a further alternative, the material of the barrier

25 or a portion of the material of the barrier could

26 comprise a material which swells when contacted with

27 liquid to increase frictional fit of the barrier in the

28 can. Such a material could be a plastic, such as nylon

29 or where the liquid is to be consumed, a suitable food-

30 safe plastic. 31

32 The apparatus may also have means to regulate and

33 control the pressure and/or volume of fluid which is

34 pressurised during insertion of the bar^ker ⁱnto the

35 container. In one example this -ay oo--pr.se grooves 8

formed on the inside walls of the container so that only a predetermined volume of fluid is pressurised.

In a further example, this may comprise one or more protuberances on the bottom surface of the barrier so that a predetermined minimum volume of gas is pressurised.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:-

Fig. 1 is a cross-sectional view through a first example of a sealed can of beer; Fig. 2 is a cross-sectional view through the bottom of the can of beer shown in Fig. 1 after the can has been opened; Fig. 3 is a cross-sectional view through a second example of a sealed can of beer; Fig. 4 is a cross-sectional view through a third example of a sealed can of beer; Fig. 5 is a cross-sectional view through a fourth example of a sealed can of beer; Fig. 6 is a cross-sectional view through a fifth example of a sealed can of beer; Fig. 7 is a cross-sectional view through a sixth example of a sealed can of beer; Fig. 8 is a cross-sectional view through the bottom of the can of beer shown in Fig. 7 after the can has been opened; and Fig. 9 is a cross-sectional view through the seventh example of a sealed can of beer; and Fig. 10 is an example of a lockable barrier for use in the seven examples above. Fig. 1 shows a can 1 which has a barrier 2 in the form of a piston mounted within the can. The barrier 2 is used to separate and isolate a pressurised gas 3 which in this example is nitrogen, from beer 4 in the can l.

The barrier 2 includes a flexible portion 5 which is formed from the same material as the rest of the barrier 2 but which is of a reduced thickness. Typically, the barrier 2 could be moulded from a plastics material, such as polyethylene. In addition, flanges 6 are formed on the outside surface 7 of the barrier 2 and these flanges engage with the internal wall of the can 1 and retain the barrier 2 in the position shown in Fig. 1.

The barrier 2 also comprises a valve member 8 mounted in an aperture 9 in the flexible portion 5 and the head of the valve member 8 seals against the flexible portion 5 when the flexible portion 5 is in the position shown in Fig. 1. This prevents the gas 3 or the beer 4 passing through the aperture 9 when the can is sealed. On the top surface 11 of the can 1 is a mechanism 12 for opening the can 1, such as a ring-pull.

In order to fill the can 1 the following procedure may be adopted. Initially the can 1, when empty, is flooded with nitrogen gas 3 and the barrier 2 is then inserted in the can 1 and pushed along the can to the position shown in Fig. 1. As the flanges 6 seal with the internal walls of the can 1 the nitrogen gas 3 is prevented from escaping past the barrier 2 and the nitrogen gas 3 becomes pressurised due to the reduction in volume. At this stage any excess pressure in the nitrogen gas 3 may be vented through the aperture 9 by 10

exerting a force on an end 10 of the valve member 8 in order to open the valve.

When the desired pressure for the nitrogen gas 3 is obtained the can 1 is then filled with beer 4 which sits on top of the barrier 2 and is isolated from the nitrogen gas 3 by the barrier 2. The beer 4 is saturated with gas at a pressure similar to the pressure of the nitrogen gas 3 so that when the can 1 is sealed the pressure of the beer 4 and the nitrogen gas 3 are approximately similar. Hence, because of the similarity in pressures between the beer 4 and the nitrogen gas 3, the flexible portion 5 of the barrier 2 stays in its sealed position as shown in Fig. 1.

Referring now to Fig. 2, when the pressure of the can 1 is released by a user opening the mechanism 12 the resulting increase in the pressure differential between the gas 3 and the beer 4 causes the flexible portion 5 of the barrier 2 to invert to the attitude shown in Fig. 2. In this attitude the head of the valve member 8 cannot seal against the flexible portion 5 and so the gas 3 escapes through the aperture 9 into the beer 4 in order to create a draught beer effect. When the can 1 is opened the flanges 6 which engage with the side wall of the can 1 retain the barrier 2 in the position shown in Figs 1 and 2 against the action of the pressure differential between the gas 3 and the beer 4.

Hence, the above example of the invention provides a method of simulating draught beer in a can of beer by using a piston type arrangement and a valve mechanism.

In addition, lugs could be provided on the inside of the can to facilitate retention of the barrier 2 within the can 1 in the position shown in Figs. 1 and 2. As an alternative to the valve member 8 and the aperture 9, the flexible portion 5 could be designed to rupture when the pressure differential across the barrier increases as the can is opened and the pressure in the beer 4 is reduced.

Fig. 3 shows a second example of the invention in which a can 1 has a barrier 20 in the form of a piston mounted within the can 1. The barrier 20 is used to separate and isolate the pressurised gas 3 from beer 4 in the can 1, as with the example shown in Figs. 1 and 2.

The barrier 20 may be formed from a plastics material and has an aperture 21 therethrough.

On the top surface 23 of the can 1, is a mechanism 24 for opening the can 1.

In use, the can 1 is flooded with nitrogen and the piston 20 is pushed down inside the can to a predetermined spacing from the base 22 of the can 1. Beer 4 is then delivered into the can above the piston 20, as shown in Fig. 3. The can is then sealed and is heated to pasteurise the beer. During the heating process the pressure of the gas in the beer 4 rises, causing some of the beer 4 to pass through the aperture 21 in the piston 20. The beer 4 which enters the chamber defined between the base 22 of the can 1 and the piston 20 pressurises the nitrogen 3 within the chamber until the pressure within the chamber equalises the pressure of the beer 4. ^{* *} PCr/GB92/02Il.

12

When, after pasteurisation, the can is cooled, a residual pressure is retained in the can 1 due to the supersaturation of the beer 4 with the nitrogen 3. The pressure within the can 1 is then greater than atmospheric pressure and the pressure of the beer 4 is equal to the pressure within the chamber defined by the base 22 and the piston 20.

When a user releases the pressure of the beer by opening the mechanism 24, there is a resulting pressure differential between, on the one hand, the fluid in the chamber defined by the base 22 and the piston 20 and, on the other hand, the beer 4 above the piston 20, so nitrogen flows upwardly through the aperture 21 into the beer 4, creating a draught beer effect.

Hence, this example of the invention also provides a mechanism in which a fluid may be released into a liquid such as beer by using a small aperture 21 which creates a rush of the fluid 3 from the chamber into the beer 4 when the pressure inside the can is released by a user opening the can.

Fig. 4 shows a third example of the invention in which a piston 30 is located in the can 1 to separate the beer 4 from the pressurised gas 3. The piston 30 is typically manufactured from a plastics material and comprises a valve 31 and a fluid reservoir 32. In this particular example the valve 31 is in the form of a silicon tube which is designed so that it closes the aperture in the piston 30 if the pressure of the beer 4 is equal to or exceeds the pressure of the gas 3. The valve member 31 opens if the pressure of the gas 3 is greater than the pressure of the beer 4. On the top surface 33 of the can 1, is a mechanism 34 for opening the can 1.

In use, the can is filled in a similar manner to that of the second example of the invention shown in Fig. 3 and when the can 1 is heated to pasteurise its contents the barrier is forced towards the base 22 by the pressure of the beer 4 and so pressurises the gas 3. Hence, when the pressure of the can 1 is released by a user opening the mechanism 24 the pressurised gas 3 is greater than the pressure of the beer 4 which causes the valve 31 to open and permit pressurised gas 3 to expel the beer 4 in the reservoir 32 into the main body of beer 4 which creates a swirling effect as well as releasing the pressurised gas 3 into the beer 4.

Hence, this third example' of the invention provides a method of simulating draught beer in a can of beer by using a barrier with a valve mechanism.

Fig. 5 shows a fourth example of the invention in which a can 40 has a barrier 41 in the form of a resilient material retained in position within the can 40 by frictional forces. The barrier 41 is used to separate and isolate a pressurised gas 42 from the beer 43 in the can 40, as with the examples shown in Figs. 1 to 4.

The barrier is typically manufactured from a plastics material and comprises a valve member 44 which closes an aperture in the barrier if the pressure of the liquid 43 is greater than or equal to the pressure of the gas 42. In the example shown the valve member 44 is a valve of the "woodcroft" type. The valve mechanism may also include a valve sleeve 45 which covers the valve member 44 and has an aperture 46. On the bottom surface of the barrier are protuberances 47, which ensure a minimum volume of gas 42, of about 15cc in a typical application. On the top surface 48 of the can 40 is a mechanism 49 for opening the can 40.

In use, the can is filled in a similar manner to that of the second and third examples of the invention shown in Figs. 3 and 4. When the can is heated to pasteurise its contents the barrier 41 is forced toward the base 50 by the pressure of the beer 43 and so pressurises the gas 42. When the pressure of the beer 43 is greater than the pressure of the gas 42 the valve member 44 remains closed. When the pressure of the can 40 is released by a user opening the mechanism 49, the pressure of the pressurised gas 42 is greater than the pressure of the beer 43 which causes the valve member 44 to open and permits gas 42 to flow upwards through the valve member 44 into the valve sleeve 45 and out through the aperture 46 into the beer 43, creating a draught beer effect in the beer.

Fig. 6 shows a fifth example of the invention in which a can 51 has a barrier 52 retained in position within the can 51 by frictional forces between the side skirt of the barrier and the inside surface of the can 51. The barrier 52 is used to separate and isolate a pressurised gas 53 from beer 54 in the can 51 as with the example shown in Fig. 5.

The barrier 52 may be formed from a plastics material and has an aperture 55 therethrough, and an associated valve mechanism 56 with a valve head 57. On the bottom surface of the barrier 52 are formed protruberances 58 which ensure a minimum volume of gas 53, of about 15 cc in a typical application. On the top surface 59 of the can 51 is a mechanism 60 for opening the can 51.

In use the can 51 is filled in a manner similar to that of the second, third and fourth examples of the invention as shown in Figs. 3, 4 and 5. When the can 51 is heated to pasteurise its contents the barrier is forced towards the base 61 by the pressure of the beer 54 and so pressurises the gas 53. When the pressure of the beer 54 is greater than the pressure of the gas 53 the valve head 57 is forced downwards such that it closes the aperture 55 in the barrier 52. When the pressure of the can 51 is released by a user opening the mechanism 60, the pressure of the pressurised gas 53 is greater than the pressure of the beer 54 which causes the head of the valve member 57 to be pushed upwards allowing gas 53 to flow upwards through the aperture 55 into the beer 54, creating a draught beer effect in the beer 54 in the can 51.

Fig. 7 shows a sixth example of the invention in which a can 70 comprises a barrier 71 retained in position within the can 70 by frictional forces. The barrier 71 is used to separate and isolate a pressurised gas 72 from the beer 73 in the can 60. The barrier 71 is typically manufactured from a semi-rigid plastics material and comprises a valve member 74, a valve sleeve 75 and protruberances 76 on the bottom surface of the barrier 71. The valve sleeve 75 includes two apertures 77 and 78 located in the side and top surfaces respectively of the valve sleeve. On the top surface of the can is a mechanism 80 for opening the can 70. In use, the can 70 is filled in a manner similar to that of examples 2 to 5 of the invention, as shown in Figs. 3 to 6. When the can 70 is heated to pasteurise its contents, the barrier 71 is forced downwards toward the base 71 by the pressure of the beer 73 and so pressurises the gas 72. The protruberances 76 ensure a minimum volume of gas 72, of about 15 cc in a typical application. The barrier 71 is retained in position by frictional force between a skirt 80 of the barrier 71 and the side wall of the can 70.

When the pressure of the beer 73 is greater than the pressure of the gas 72, the valve member 74 remains closed and in a substantially vertical attitude, which allows the beer 73 to enter the sleeve 75 through the apertures 77 and 78 in the above sleeve 75.

Referring now to Fig. 8, when the pressure in the can 70 is released by a user opening the mechanism 80 to provide an aperture 82, the pressure of the pressurised gas 72 is greater than the pressure of the beer 73 and the gas 72 flows upwards through the valve member 74 which causes it to open and tilt towards the attitude shown in Fig. 8. In this attitude, the valve member 74 seals the aperture 77 on the side surface of the valve sleeve 75. This permits the pressurised gas 72 to flow upwards through the valve member 74 into the valve sleeve 75 and expel beer 73 in the valve sleeve 75 through the aperture 78. This creates a rush of liquid and gas into the beer 73 creating a draught beer effect in the beer in the can 70.

Fig. 9 shows a seventh example of a sealed can of beer 90. The can 90 comprises a valve 91 which is typically, in the form of a ring-pull type closure. The can 90 contains a barrier 92 which comprises a body member 93 made of a substantially rigid material, such as a plastic which has an aperture 95 therein. Extending across the aperture 95 is a micro-porous membrane 94 which is gas permeable but is substantially impermeable to liquid, such as beer 96 in the can 90. Located below the membrane 94 is a gas space 97. Typically, the aperture 95 has a diameter of approximately 0.012 inches.

The barrier 93 may be fixed in position, for example, by adhesive, by flanges in the inside of the can 90, or by manufacturing the body member 93 from a material, such as a plastic, which swells when in contact with the beer 96 to increase the frictional fit of the barrier 92 in the container 90.

The membrane 94 permits equalisation of pressure between the beer 96 and air space 97 when the cam 90 is stored. However, when the ring-pull 91 is opened the pressure in the beer 96 where the barrier 92 drops to atmospheric pressure, which creates a pressure differential across the barrier 92. This causes gas in the space 97 to pass through the membrane 94 and through the aperture 95 and so into the beer 96 above the barrier 92. The size of the aperture 95 is chosen so as to create a rush of gas through the aperture 95 which creates a draught beer effect in the beer 96.

Fig. 10 shows a barrier 102 which could be used with any of the seven examples described above. In Fig. 10 the barrier 102 is positioned in a can 100 with the bottom edges of central portion 103 contacting the base 101 of the can 100. As side flanges 104 of the barrier 102 are fixed further towards the base 101, in the direction of arrows 105, the intermediate portion 106 of the barrier 102 moves in the direction of arrows 107. When the flange 104 has reached the position shown in phantom in Fig. 10, the intermediate portion 106 is also in the position shown in phantom. In the position shown in phantom, the portion 106 forces the flange 104 in outwardly in the direction of arrows 108 to increase the frictional fit of the barrier 102 in the can 100 and lock the barrier 102 in position in the can. The dimension and design of the intermediate portion 102 is chosen so that the intermediate portion 102 locks into the position shown in phantom and does not revert to its original position, for example, because the pressure below the barrier 102 is greater than the pressure above, as would occur when a sealed can of beer is opened.

The barrier 102 may be manufactured from a plastic material and the intermediate portion 102 coupled to the central portion 103 and flange 104 by plastic webs which act as hinges.

This type of lock mechanism may be used to lock the barrier 102 in position before liquid such as beer is inserted into the can 100, or alternatively may activate during pasteurisation of the beer when the barrier is forced to travel towards the base of the can due to pressure differentials due to the pasteurisation process.

Similarly, with appropriate modification and/or additions to the central section 103, the barrier 102 could be used with valve mechanisms and/or a gas- permeable membrane, such as a micro-porous membrane. Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. A method of producing a containerised liquid comprising providing a container having a rupturable wall portion, introducing a gas into the container, providing in the container a barrier which is gas- permeable and is substantially impermeable to liquid, introducing a liquid pressurised with gas in the container on the other side of the barrier, and sealing the container.

2. A method according to Claim 1, the method further comprising the steps of pressurising the liquid to force gas from the liquid through the barrier to the one side of the barrier.

3. A method according to Claim 2, wherein the step of pressurising the liquid comprises raising the temperature of the liquid in the can.

4. A method according to any of the preceding Claims, wherein the barrier is fixed within the container.

5. A pressurised container having a rupturable wall portion comprises a barrier which is gas-permeable and is substantially impermeable to a liquid in the container, the barrier dividing the container into first and second chambers, the barrier permitting passage of a gas in the container between the chambers so that when the wall portion is ruptured to permit one of the chambers to communicate with atmospheric pressure and creates a differential pressure between the chambers, gas in the other chamber flows through the barrier into the one chamber.

6. A pressurised container according to Claim 5, wherein the liquid is contained in the one chamber.

7. A pressurised container according to Claim 5 or Claim 6, wherein the barrier comprises a body member substantially impermeable to the gas and the liquid and having an aperture therein, and a gas-permeable membrane covering the aperture.

8. A pressurised container according to Claim 7, wherein the aperture has a diameter of approximately 0.010 to 0.015 inches.

9. A pressurised container according to Claim 8, wherein the aperture has a diameter of approximately 0.012 inches.

10. A pressurised container according to any of Claim 5 to 9, wherein the barrier comprises a material which swells when in contact with the liquid.

11. A pressurised container according to any of Claims 5 to 10, wherein the barrier comprises a movable portion which moves to fix the barrier within the container.

12. A method of producing a containerised liquid comprising providing a container having a rupturable wall portion, introducing a fluid into the container, providing in the container a barrier which is substantially impermeable to the fluid on one side of the barrier, the barrier having means for selectively allowing passage of the fluid through the barrier, providing a liquid in the container on the other side of the barrier, and sealing the container.

13. A pressurised container having a rupturable wall portion comprises a barrier substantially impermeable to a pressurising fluid and a liquid in the container, the barrier dividing the container into first and second chambers and including a pressure operable valve mechanism movable between a closed position and an open position, the valve mechanism allowing passage of the fluid and/or liquid between the chambers when the wall portion is ruptured to permit one of the chambers to communicate with atmospheric pressure to create a differential pressure between the chambers, the valve mechanism preventing such passage when the pressures are equal.

14. A method of producing a pressurised liquid comprises introducing a fluid into the container, providing in the container a barrier which is substantially impermeable to the fluid and the liquid, so that the liquid is maintained on one side of the barrier, the barrier having means for selectively allowing passage of the fluid through the barrier, introducing a liquid into the container on the other side of the barrier, pressurising^" the liquid to displace the barrier to pressurise the fluid, and sealing the container.