GB2353265A

GB2353265A - Beverage frothing device

Info

Publication number: GB2353265A
Application number: GB0012052A
Authority: GB
Inventors: Jon Brown
Original assignee: Scottish and Newcastle Ltd
Current assignee: Heineken UK Ltd
Priority date: 2000-05-18
Filing date: 2000-05-18
Publication date: 2001-02-21
Anticipated expiration: 2020-05-18
Also published as: GB0012052D0; GB2353265B

Abstract

A device for inclusion in a pressurised beverage container for jetting gas into a beverage in the container upon opening the container comprises a housing (13,23) defining an internal chamber (30) provided with spaced lower and upper permanently open orifices (22,12). The internal chamber (30) is adapted to contain pressurised gas and a quantity of beverage. The upper orifice (12) is located above and the lower orifice (22) below the level of beverage in the device prior to firing of the device when the container is opened. The upper orifice (12) is in communication with the internal chamber through an upper standpipe (11) which, immediately prior to firing of the device, opens into the internal chamber (30) below the surface level of the beverage held within the container. The device further comprises upper and lower well structures (15,25) on an external surface of the device in which are respectively located the upper and lower orifices (12,22), and in which, upon firing, beverage from within the device is forced towards the upper orifice (12) such that pressurised gas from the internal chamber (30) is preferentially expelled through the lower orifice (22) into the beverage in the container.

Description

2353265 BEVERAGE FROTHING This invention relates to generating a foaming

dispersion of bubbles within a liquid packed within a sealed, broachable container. It is particularly, but not exclusively, suited for use with canned or otherwise packaged beverages, for example, beer, ale, porter, stout or lager, to produce a close-knit, creamy head on a beverage when the sealed container is opened.

EP 0 833 787 provides a device for generating a head on a liquid in a sealed and pressurised can, when the can is opened, comprising a substantially spherical capsule designed to float in the beverage contained within the sealed container such that a lower orifice is positioned below the surface level of the beverage and an upper orifice is positioned above the surface level. A lower extension tube extends inwardly a very small distance from the lower orifice and an upper extension tube extends co-linearly to the lower extension tube from the upper orifice to a position slightly above the lower orifice.

The lower and upper orifices are substantially the same size. In use, the device is placed into the container and the container and contents are then purged of any oxygen by evacuating the container and contents. Subsequently, beverage is filled into the container and liquid nitrogen is dosed into the container onto the liquid surface before the same is sealed in the usual way. The liquid nitrogen evaporates creating a nitrogen filled primary head space in the sealed container. As more nitrogen evaporates, the internal pressure in the container rises and nitrogen gas from the primary head space is forced into the device through the upper orifice and the upper extension tube. Beverage is also forced into the device through the lower orifice and the lower extension tube, but much more slowly. When the pressure inside the container stabilises, the device is left partially filled with beverage with an internal, secondary head space filled with nitrogen gas originating from the nitrogen dose and carbon dioxide gas originating from the beverage at a pressure substantially equal to that within the primary head space.

on opening of the container, for example, by means of opening a ring pull, the pressure in the primary head space above the beverage is reduced rapidly to atmospheric pressure. The pressurised nitrogen and carbon dioxide gases within the device consequently force liquid held within the device upwardly along the upper extension tube towards the upper orifice. Referring to Figure 1, which shows such a prior art device, once the liquid level inside the device drops below the end of the lower extension tube, liquid trapped in the upper extension tube continues to be pushed up this tube but mixed gas is forced preferentially through the lower orifice into the body of the beverage to produce the desired frothing effect.

In order to achieve satisfactory performance with such insertable devices, it is vital that any oxygen or ambient air within the device is removed, in order that oxidation or deterioration of the beverage is prevented during storage. One proposed method, as disclosed above, of achieving this is by means of purging the device by evacuation, back-filling with non-oxidising gas and then submerging the devices in water by partially filling the containers with water until the containers are filled with beverage. The aim is to prevent ambient air or oxygen from entering the device by the presence of the water. The containers and purged and submerged devices are then conveyed to an insertion point where the water is removed and the containers are filled with beverage. A problem found with the described process is that the devices are naturally buoyant in water. It is therefore necessary to provide means for actively holding the devices below the water surface level in the containers. This is complicated and often impractical.

An alternative proposed method is to purge the devices in the containers in the same manner and to convey them to the insertion point without submerging the devices in water. The aim of this method being to transfer the devices quickly enough to prevent unwanted ingress of ambient air or oxygen. The proposed method relies on the orifices in the device being small enough to prevent ingress or ambient air or oxygen during the period between the devices exiting the purger and being submerged by the beverage in the containers. However, it has been found that exposure of the devices to the air for as little as two minutes results in unacceptable levels of oxygen being taken up by the devices. For practical reasons, the time taken for transporting the devices between the purger and the insertion point is greater than two minutes to allow for an adequate buffer supply of containers at the insertion point to allow for batch filling to take place at an economic rate. Hence, the degree of ingress of ambient air or oxygen is unacceptable even where the orifices are small. Additionally, the filling line, which includes the purger and insertion point may be stopped for a number of reasons. This may be due to a blockage or breakdown of any of the machinery on the filling line or to allow for maintenance or loading of any of the machines of the filling line. As a result, some devices may be held for extended periods of much greater than two minutes between the purger and the insertion point. This degree of delay results in a substantial degree of ingress of oxygen or ambient air into the devices even where the orifices are small.

As a result, the proposed method has been found to be unworkable.

A further disadvantage with the device of EP 0 833 787 is that whilst the device performs satisfactorily at ambient temperatures it is underpowered and fails to provide a sufficient quantity of head when the beverage -cont a ining can is opened after being stored in a refrigerator.

It is an object of the present invention to provide a device which overcomes these problems.

Accordingly, the present invention provides a device for inclusion in a pressurised beverage container for jetting gas into a beverage in the container upon opening the container, the device comprising a housing defining an internal chamber provided with spaced lower and upper permanently open orifices, the internal chamber being adapted to contain pressurised gas and a quantity of beverage, the upper orifice being located above and the lower orifice being located below the level of beverage in the device prior to firing of the device when the container is opened, the upper orifice being in communication with the internal chamber through an upper standpipe which, immediately prior to firing of the device, opens into the internal chamber below the surface level of the beverage held within the container, the device further comprising upper and lower well structures on an external surface of the device in which are respectively located the upper and lower orifices, and in which, upon firing, beverage from within the device is forced towards the upper orifice such that pressurised gas from the internal chamber is preferentially expelled through the lower orifice into the beverage in the container.

- 5 Preferably the upper and lower orifices are located at the base of their respective well structures.

Preferably the upper orifice has a diameter of between 100 and 700 microns.

In one embodiment the upper orifice has a diameter of 200 microns.

Preferably the lower orifice has a diameter between 100 and 700 microns.

In one embodiment the lower orifice has a diameter of 400 microns.

Preferably the upper well structure has a chamfered opening.

Preferably the lower orifice communicates with the internal chamber through a lower standpipe and the upper standpipe extends partially within the lower standpipe such that a lower end of the upper standpipe extends within between 0.5 and 2.0 millimetres of a lower end of the lower standpipe.

Preferably the upper well structure has an axial length of between 10 and 15 millimetres.

Preferably the internal chamber has a volume of gas after charging of between 6 and 10 millilitres.

In one embodiment the volume of gas after charging is 7 millilitres.

The present invention also provides a method of packaging a beverage having a gas in solution therewith which comprises providing a device as previously described, inserting the device into a container, evacuating the device to remove ambient air and/or oxygen from the internal chamber, flushing the device with a non-oxidising gas, depositing liquid droplets in the lower and upper well structures so as to prevent ingress of ambient air and/or oxygen into the internal chamber, partially filling the container with a beverage, dosing the container with liquid nitrogen or other volatile fluid and sealing the 6 container.

Embodiments for the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which:5 Figure 1 shows a cross-sectional view of a prior art device during firing;

Figure 2 shows a side view of a first part of a device according to the present invention; Figure 3 shows a cross-sectional view taken on line III-III of Figure 2; Figure 4 shows a cross-sectional view of detail IV of Figure 3; Figure 5 shows a plan view of the part of the is device of Figure 2; Figure 6 shows a side view of a second part of a device according to the present invention; Figure 7 shows a cross-sectional view on line VII-VII of Figure 6; Figure 8 shows a plan view of the part of the device of Figure 6; Figure 9 shows a cross-sectional view of detail IX shown of Figure 7; Figure 10 shows a cross-sectional view of the first and second parts of the device as assembled in an inoperative state; Figure 11 shows the device of Figure 10 in a state immediately prior to firing; and Figure 12 shows the device of Figure 10 being fired.

The device 1 of the present invention is provided as a separate hollow insert for inclusion in a beverage container.

Throughout the description and claims, references to "upper"' and "lower" are references to such relative positions in relation to the device 1 as intended to be orientated within a beverage container when the beverage container is opened. Throughout the description and claims, references to "fluid" may encompass both liquids and gases.

The device 1 comprises an upper cup-shaped member defining wall portion 13, as shown in Figures 2 and 3, and a lower cup-shaped member 20 defining a wall portion 23, as shown in Figures 6 and 7.

Each of the upper and lower cup-shaped members 10, 20 forming the device 1 are moulded from a plastics material such as polypropylene. The device 1 is substantially rigid when assembled.

The members 10, 20 are joined by means of a circumferential weld (which also provides a seal) formed by heat, ultrasonics or other known means.

Alternatively, the two members may be joined by a clip. Once welded together, the upper and lower cup shaped members 10, 20 define an internal chamber 30 within the device 1. The volume of the internal chamber 30 is such that when charged, immediately prior to f iring of the device the volume of gas held in internal chamber 30 is between 6 and 10 millilitres. Preferably the contained gas volume is 7 millilitres.

A lower extension tube or standpipe 21 is formed integrally with the lower cup-shaped member 20 and defines a lower passageway 24 which provides fluid communication from an upper end 28 of the lower extension tube 21 within the internal chamber 30 to a lower orifice 22 at the lower end 29 of the lower extension tube 21. The lower orifice 22 provides fluid communication between lower passageway 24 and the exterior of device 1.

An external tubular extension of the lower cup shaped member 20 defines a lower well 25 enclosing the lower orifice 22 at its base.

An upper extension tube or standpipe 11 is formed integrally with the upper cup-shaped member 10. The upper extension tube 11 is provided with a restricted portion 40 at a point along its length between a lower end 18 and an upper end 16. As shown in the figures, the restricted portion 40 at an approximately midpoint of upper extension tube 11. However, the exact position may be varied. The upper extension tube 11 defines an upper passageway 14 below the restricted portion 40 and an upper well 15 above the restricted portion 40. Upper passageway 14 provides communication between the internal chamber 30 and the upper well 15, which in turn is in communication with the exterior of the device 1. An upper orifice 12 is provided at the restricted portion 40 to provide fluid communication between the upper passageway 14 and upper well 15.

Preferably, the upper well 15 is provided with a chamfered opening 16 at its upper end, as shown in Figure 3. Preferably the chamfer 16 of the opening is at an angle of 45 degrees to the radial.

The lower orifice 22 and upper orifice 12 may be moulded integrally with the cup-shaped members 10, 20 or formed after moulding by any known means, for example, laser drilling or piercing. The dimensions of the orifices 12, 22 may be varied depending on the beverage to be dispensed. A high carbonation beverage such as a lager requires a less powerful injection of gas to achieve the desired head formation compared to a low carbonation beverage such as an ale or stout.

Hence the upper and lower orifices 12, 22 may both vary between 100 and 700 microns in diameter. Typically for a low carbonation beverage the lower orifice 22 is approximately 400 microns in diameter and the upper orifice 12 is approximately 200 microns in diameter. For a high carbonation beverage both the lower and upper orifices 12, 22 are approximately 500 microns in diameter.

- 9 As shown in Figure 4, an upper end 19 of upper passageway 14 adjacent the upper orifice 12 is angled to form a frusto-conical portion 17. Preferably the walls of the frusto-conical portion 17 are angled at 60 degrees to the radial.

As shown in Figure 9, lower end 29 of the lower extension tube 21 is provided with a frusto-conical portion 27 adjacent the lower orifice 22. Preferably the walls of the frusto-conical portion 27 are angled at 30 degrees to the radial.

The lower extension tube 21 is also provided with four slots 41 towards the lower end 29 in a cruciform orientation with the lower orifice 22 at the centre as shown in Figure 8. The slots 41 are equi-spaced around the circumference of the lower extension tube 21 at 90 degree intervals. The slots 41 extend part way up the axial length of the lower extension tube 21 as shown in Figure 6 and part-way through the thickness of the lower extension tube 21.

As shown most clearly in Figure 10, the upper extension tube 11 extends downwardly to a greater extent than the lower extension tube 21 extends upwardly. In addition, the internal diameter of the lower extension tube 21 is greater than the external diameter of the upper extension tube 11, such that when the upper and lower cup-shaped members 10, 20 are assembled, as shown in Figure 10, the upper extension tube 11 extends downwardly within the lower extension tube 21. Preferably, the lower end 18 of the upper extension tube 11 extends downwardly such that it is only a small distance above the lower end 29 of the lower extension tube 21. Typically, the distance between the lower end 18 of the upper extension tube 11 and the lower end 29 of the lower extension tube is approximately 1 millimetre.

The relative amounts of material in the upper and lower cup-shaped members 10, 20 is such that the device 1 when inserted in a beverage container floats with the lower cup- shaped member 20 lowermost.

In a preferred method of use, the device 1 is inserted in a container and the container and device are purged to remove any ambient air or oxygen.

Purging is achieved by applying a vacuum or partial vacuum to the device 1 to evacuate any ambient air or oxygen in a known manner. The container and device 1 are then flushed with nitrogen gas and immediately transported to a sprayer where the device 1 is sprayed with liquid water.

As a result, the container is partially filled with water and droplets of water are deposited in the upper well 15 and the lower well 25 to thereby seal the lower and upper passageways 24, 14. The water droplets are firmly retained due to surface tension. The chamfer 16 at the upper end of upper well 15 increases the reliability of deposit of the water droplet in the upper well 15. It has been found that a reliable seal is formed where the lower well 25 has an axial length of 2 millimetres. Likewise, a reliable seal may be formed in the upper well 15 where its axial length is 2 millimetres. However, further advantageous effects are produced by increasing the axial length of the upper well 15 as described below.

An advantageous effect has been found where the water sprayed onto the device 1 is at a lower temperature than the nitrogen gas used to flush the internal chamber 30. The relatively cold water causes the nitrogen gas within the internal chamber 30 to contract causing the droplets of water in the upper and lower wells 15, 25 to be drawn down against the lower and upper orifices 22, 12, thus improving the integrity of the seal. In this way the devices 1 may be rolled, knocked or dropped without dislodging or unsealing the lower and upper orifices 22, 12. The presence of the droplets also means that although the devices 1 will tend to float in the partially waterfilled containers and hence may be left exposed to the atmosphere, ambient air or oxygen does not enter the internal chamber 30. It has been found that devices 1 according to the present invention may remain exposed to atmosphere for over two hours without detrimental effect.

The devices 1 are transported from the sprayer to the beverage filling point in a known manner. Because there is no requirement for the devices 1 to be submerged during transport the complexity of the machinery required is much reduced. For example, there is no need to evacuate the assembly line or provide a positive pressure of nitrogen gas.

Likewise, the ease of operation is much increased.

Normally the container is rinsed and then filled with a beverage, for example a beer supersaturated with gas, from a filler head, in the usual way. The device 1 floats at the surface level of the beverage such that it is partially submerged, the lower orifice 22 being below the surface level of the beverage and the upper orifice 12 being above the surface level.

Liquid nitrogen is then dosed into the top of the container and the container is seamed in the usual way. Evaporation of the liquid nitrogen creates a nitrogen filled head space in the sealed can above the surface level of the beverage. At the same time evaporation of the liquid nitrogen forces gas from the headspace into the internal chamber 30, via the upper orifice 12 and upper passageway 14, such that the internal pressure within the device 1 increases. A small quantity of beverage 43 and carbon dioxide from the beverage are also forced into the internal chamber 30 via the lower orifice 22, as shown in Figure 11.

The quantity of beverage which enters the device 1 may be such that it overflows the lower passageway 24, referenced in Figure 11 by numeral 44. If excess beverage 44 enters the internal chamber 30 it will overflow the lower extension tube 21 and be retained in lower cup-shaped member 20. The volume of beverage in the lower passageway 24 is such that the lower end 18 of the upper extension tube 11 is submerged in the beverage 43. Thus in a equilibrium state, as shown in Figure 11, when the pressure in the can has stabilised, there exists a liquid lock preventing pressurised gas in the internal chamber 30 exiting either the lower or upper orifices 22, 12.

When desired to be used, the can is broached, by means for example of a ring pull. The pressure in the headspace is instantaneously reduced to atmospheric. As a result there exists a positive pressure differential between the internal chamber 30 and atmosphere. Consequently gas in the internal chamber 30 forces the quantity of beverage 43 trapped in the lower passageway 24 round and up into the upper passageway 14 where it contacts the upper orifice 12, as shown in Figure 12. The volume of beverage 43 originally trapped in the lower passageway 14 is controlled by the dimensions of lower passageway 14 such that when the beverage 43 contacts the upper orifice 12, substantially all of the beverage is contained in the upper passageway 14, as shown in Figure 12, such that lower orifice 12 is substantially clear of beverage enabling pressurised gas in the internal chamber 30 to exit the lower orifice 22 into the main body of beverage contained in the can as a jet 46 which produces the desired frothing effect. A very small volume of beverage may also exit lower orifice 22 together with the pressurised gas. However this has been found not to affect the frothing of the beverage. Excess beverage 44 which may have overflowed the lower extension tube 21 on pressurisation of the can is prevented from fouling the lower orifice 22 by the presence of the lower extension tube 21.

The slots 41 aid the flow of pressurised gas as it exits the internal chamber 30 via the lower orifice 22.

It has been found that operation of the device 1 is improved by positioning the upper orifice 12 at approximately the midpoint of the upper extension tube 11 rather than at an upper end. As a result beverage 43 has a smaller distance to travel before contacting upper orifice 12, leading to a quicker response on broaching the container which in turn ensures that a greater proportion of the pressurised gas in internal chamber 30 exits through the lower orifice 22 rather than the upper orifice 12. Additionally, locating the upper orifice 12 at approximately the midpoint results in upper well 15 being of greater depth. This in turn has beneficial effects in ensuring a better seal between the water droplet and the upper well 15 and the tendency for the water droplet to be drawn down upper well 15 as described above.

Claims

Claims:

1. A device for inclusion in a pressurised beverage container for jetting gas into a beverage in the container upon opening the container, the device comprising a housing defining an internal chamber provided with spaced lower and upper permanently open orifices, the internal chamber being adapted to contain pressurised gas and a quantity of beverage, the upper orifice being located above and the lower orifice being located below the level of beverage in the device prior to firing of the device when the container is opened, the upper orifice being in communication with the internal chamber through an upper standpipe which, immediately prior to firing of the device, opens into the internal chamber below the surface level of the beverage held within the container, the device further comprising upper and lower well structures on an external surface of the device in which are respectively located the upper and lower orifices, and in which, upon firing, beverage from within the device is forced towards the upper orifice such that pressurised gas from the internal chamber is preferentially expelled through the lower orifice into the beverage in the container.

2. A device as claimed in claim 1 wherein the upper and lower orifices are located at the base of their respective well structures.

3. A device as claimed in any preceding claim wherein the lower or upper orifice has a diameter of between 100 and 700 microns.

4. A device as claimed in claim 3 wherein the upper orifice has a diameter of approximately 200 microns.

5. A device as claimed in claim 3 or claim 4 wherein the lower orifice has a diameter of approximately 400 microns.

6. A device as claimed in claim 3 wherein the upper and lower orifices have a diameter of approximately 500 microns.

7. A device as claimed in any preceding claim wherein the upper well structure has a chamfered opening.

8. A device as claimed in any preceding claim wherein the lower orifice communicates with the internal chamber through a lower standpipe and the upper standpipe extends partially within the lower standpipe.

9. A device as claimed in any preceding claim wherein the volume of the internal chamber is such that, prior to firing the device, the internal chamber contains between 6 and 10 millilitres of gas.

10. A device as claimed in claim 9 wherein the volume of gas is 7 millilitres.

11. A pressurised beverage container containing a device as claimed in any preceding claim.

12. A method of packaging a beverage having a gas in solution therewith which comprises providing a device as claimed in any of claims 1 to 11, inserting the device into a container, evacuating the device and container to remove ambient air and/or oxygen from the internal chamber, flushing the device with a nonoxidising gas, depositing liquid droplets in the lower and upper well structures so as to prevent ingress of 16 - ambient air and/or oxygen into the internal chamber, partially filling the container with a beverage, dosing the container with liquid nitrogen or other volatile fluid and sealing the container. 5

13. A device substantially as hereinbefore described with reference to and as shown in Figures 2 to 12.

14. A method substantially as hereinbefore described with reference to and as shown in Figures 2 to 12.

17 Amendments to the claims have been filed as follows A device for inclusion in a pressurised beverage container for jetting gas into a beverage in the container upon opening the container, the device comprising a housing defining an internal chamber provided with spaced lower and upper permanently open orifices, the internal chamber being adapted to contain pressurised gas and a quantity of beverage, the upper orifice being located above and the lower orifice being located below the level of beverage in the device prior to firing of the device when the container is opened, the upper orifice being in communication with the internal chamber through an upper standpipe which, immediately prior to firing of the device, opens into the internal chamber below the surface level of the beverage held within the container, the device further comprising upper and lower well structures in which are respectively located the upper and lower orifices, and in which, upon firing, beverage from within the device is forced towards the upper orifice such that pressurised gas from the internal chamber is preferentially expelled through the lower orifice into the beverage in the container.

1% 5. A device as claimed in claim 3 or claim 4 wherein the lower orifice has a diameter of approximately 400 microns.

8. A device as claimed in any preceding claim wherein the lower orifice communicates with the is internal chamber through a lower standpipe and the upper standpipe extends partially within the lower standpipe.

10. A device as claimed in claim 9 wherein the volume of gas is 7 millilitres.

11. A.pressurised beverage container containing a device as claimed in any preceding claim.

12. -A method of packaging a beverage having a gas in solution therewith which comprises providing a device as claimed in any of claims 1 to 10, inserting the device into a container, evacuating the device and container to remove ambient air and/or oxygen from the internal chamber, flushing the device with a nonoxidising gas, depositing liquid droplets in the lower and upper well structures so as to prevent ingress of - IR - ambient air and/or oxygen into the internal chamber, partially filling the container with a beverage, dosing the container with liquid nitrogen or other volatile fluid and sealing the container.