WO2005042376A1

WO2005042376A1 - Floating insert usable in a pressurised beverage container

Info

Publication number: WO2005042376A1
Application number: PCT/GB2004/004507
Authority: WO
Inventors: Matthew Cooper; Jonathan Middlemiss
Original assignee: Farm Produce Marketing Limited; Polimoon Packaging Limited
Priority date: 2003-10-24
Filing date: 2004-10-22
Publication date: 2005-05-12
Also published as: GB2407806A; GB0423478D0; GB0324772D0

Abstract

A floating insert (10) is disclosed having a body defining a single chamber (24) containing gas and a first liquid (18), the floating insert being usable in a pressurised container (28) containing a second liquid (30) which is different from the first liquid, such that when the container is opened the gas and the first liquid are jetted from the floating insert into the second liquid, and mixing of the first and second liquids occurs within the container. The floating insert comprises an upper moulding (12) including a gas inlet passage (20) to allow gas at greater than atmospheric pressure to enter the floating insert from a headspace in the container and equalise in pressure with the headspace, and a lower moulding (14) including a gas outlet passage (22) to allow the gas and the first liquid to be jetted from the insert into the second liquid in the container.

Description

FLOATING INSERT USABLE IN A PRESSURISED BEVERAGE CONTAINER

The present invention relates to a floating insert for containing a gas and a first liquid inside a pressurised container which contains a second, different liquid such that when the container is opened, the gas and the first liquid are jetted from the insert to cause foaming of the second liquid, and mixing of the first and second liquids in the container.

Systems for jetting gas into a carbonated, previously pressurised liquids such as a beverage are known. For example, GB 2 183 592 relates to a container including a separate hollow insert having an aperture in its side wall; as the container is filled, beverage is introduced into the insert via this aperture. When the container is opened, beverage from the insert is jetted through the aperture into the beverage in the container, causing the beverage to shear and foam.

WO 03/039992 discloses an insert, which is fixed to the base of a pressurised beverage container, which insert comprises two chambers. The first chamber contains a liquid component, and the second chamber contains gas which has been pressure equilibrated by means of inversion of the beverage container, with pressurised gas in the headspace of the container. Upon opening of the container, both the liquid component and the gas are released into the main body of the beverage container, mixing the liquid component with the beverage stored therein. However, this system is relatively complicated, requiring a number of parts to be precision moulded and assembled. In addition, it is not designed to be free floating, and as a result requires inversion of the container for a period of time to allow equilibration of the head space and one of the chambers.

GB 2 322 614 describes a free floating insert. This insert is formed from two mouldings, the first containing an inlet valve and the second an outlet valve which snap fit together to form the chamber of the insert. This insert, and other inserts of this type, are designed for use in pressurised sealed containers which contain carbonated liquids and have a headspace filled with pressurised inert gas. The insert is added to the container at atmospheric pressure, and floats in the headspace of the container. Upon sealing of the container under pressure, the inlet valves equilibrates the pressure inside the chamber of the insert with the pressure of the gas in the headspace by allowing the gas to enter the chamber. The insert is designed to allow lower viscosity gas to enter the insert chamber in preference to the higher viscosity liquid. Upon opening of the container, the gas sealed within the headspace of the container is released. Consequently, the gas within the insert is at a significantly higher pressure than the surroundings; this in turn causes jetting of the gas out of the insert via the gas outlet passage and into the liquid. This causes shear of the carbonated beverage and resultant foaming of the beverage to produce foaming.

EP 1 055 614 also discloses a free floating insert for use in pressurised sealed containers. This insert may be clip or heat sealed and comprises two mouldings, the upper moulding including a gas inlet passage and the lower moulding including a gas outlet passage. WO 01/51367 teaches a range of inserts which may be floating or fixed within a pressurised sealed container, in particular bottles. These inserts contain gas and liquid wherein the liquid comprises high proportion of the internal volume of the liquid. The inserts of WO 01/51367 may be single or multi-chamber and may include duckbill valves. In particular Figure 8 of this document represents a simple, single chamber insert, comprising two duckbill valves. However, this insert is designed to be affixed to the base of a container, and upon opening the container the liquid is jetted from the insert upwards into the main body of the container. Accordingly, this document does not address the problem of providing free floating inserts which incorporate weight differentials to ensure that the gas and liquid outlet valve jets the contents of the insert into a second liquid.

None of the above systems provide a simple, two-piece, free floating insert which may be used for the jetting of one liquid into a second different liquid providing mixing of the two liquids, in combination with the jetting of a gas into the second liquid.

The present invention provides each of these features in a simple, easy to manufacture product which comprises just two components.

According to a first aspect of the invention, there is provided a floating insert having a body defining a single chamber containing gas and a first liquid. The floating insert is usable in a pressurised container containing a second liquid, which is different from the first liquid, such that when the container is opened the pressurised gas in the insert and the first liquid are jetted from the floating insert into the second liquid, with mixing of the first and second liquids occurring within the container. The floating insert comprises an upper moulding including a gas inlet passage to allow gas at greater than atmospheric pressure to enter the floating insert from a pressurised headspace in the container and equalise in pressure with the headspace, and a lower moulding including a gas outlet passage to allow the gas and the first liquid to be jetted from the insert into the second liquid in the container. The chamber is formed after addition of the first liquid into one of the lower moulding or the inverted upper moulding, by snap fitting the peripheral edge of the upper or lower moulding onto a peripheral edge of the other of the upper or lower moulding to form the sealed floating insert.

The use of a snap fit insert provides an advantage for filling the insert which is not offered by known liquid containing inserts. As the liquid can be added prior to assembly of the insert this process can be achieved with a high through put and at low cost making the production of liquid containing inserts more commercially viable. In general prior art inserts require the liquid to be forced into the insert after assembly, this can be time consuming and with some designs of insert can lead to damage of the gas inlet valve system. For example, addition of the first liquid into a duckbill valved insert would require the manufacturer to force the liquid into the insert via the duckbill valve. This would damage the valve leading to significant leakage problems. The floating insert of the invention have many potential uses, and may be utilised in any application where it is desirable to keep two different solutions separate prior to use. This may be for aesthetic reasons, or because the liquids are unstable when mixed such that prior mixing and storage would lead to degradation of the product. For example, the insert may be used with carbonated or other effervescent drinks, wherein the first liquid may be colouring and/or flavouring and the second liquid could for example be a translucent or colourless liquid, for instance a clear or coloured fizzy drink, or milk. In this case mixing of the two liquids would create a dramatic colour change effect which would be particularly suitable for marketing to children.

Alternatively, the first liquid could be an alcoholic spirit and the second liquid a non-alcoholic 'mixer' typically used with the spirit to provide a product offering freshly prepared alcoholic drinks or vice versa. Examples of this type of use would include the fresh preparation of 'lager and lime' or 'cider and black' type drinks.

A further application of this insert could be the injection of a first liquid containing a concentrated vitamin or mineral solution into, for example a fruit or other non-alcoholic drink to provide a chink with high vitamin or mmeral content for the consumer. Alternative uses could include medical preparations, whereby the first and second liquids contain different pharmaceutical actives which would be unstable if mixed before use. Alternatively, the first liquid could be a tonic or medicinal preparation which is mixed with water, prior to consumption by the user. Additionally, the insert could be used by the cosmetic industry, in particular with hair colourants, where many complex packaging systems have been produced to keep the colourant and the developer separate prior to use. It is also envisaged that the first liquid may be a setting agent for products such as wall paper pastes. Alternatively, the first liquid could be a personal cleansing solution, for example face wash or bubble bath.

A particularly preferred combination of liquids for use according to the invention is a second liquid which is milk which if desired, may be effervescent. In this case the first liquid may be a coloured, optionally flavoured liquid. Especially when presented in a transparent outer container, the translucent nature of milk means that the "visual effect of the coloured first liquid jetting into the milk is particularly appealing, especially to children.

In particular, the translucency of the milk can create a visually pleasing 'clouding' effect upon opening the container as the first liquid disperses through the second liquid. It is possible, if desired, to enhance this effect by blocking parts of the gas outlet passage so that, for example, the first liquid jets from the insert in two or more distinct directions creating interesting dispersion effects within the second liquid. Further, the consistency of milk is such that excessive frothing of the milk will not occur and a creamy smooth palate texture is observed. Excessive frothing of the second liquid upon jetting of the gas and first liquid into the second liquid is undesirable as this can lead to the second liquid over flowing the container leading to spillage of the product.

According to a second aspect of the invention, there is provided a pressurised container including one or more floating inserts according to the first aspect of the invention. Conveniently, the container is a beverage container. The beverage may be effervescent, (e.g. a 'fizzy' or 'sparkling' liquid) or a liquid which has not been treated to add additional gas, (i.e. a non-effervescent, 'still' liquid). An advantage with beverages that contain gas in solution is that jetting of the gas from the insert into the beverage can cause a desirable foaming or 'head'. In the context of effervescent milk, a particularly desirable milk shake may be formed.

The tenn 'effervescent' as used herein is given it's common meaning in the trade and refers to liquids which have been treated to incorp orate additional gas into solution, for example carbon dioxide, argon, nitrous oxide or other gas soluble in the second liquid. The tenn 'still' also given it's common general meaning and is used to refer to liquids which have not been treated to contain additional dissolved gas in solution.

Preferably, the insert is made from a plastics material, and the inlet and outlet passages comprise an elongate slit. The insert may be made from a thermoplastic polymer such as nylon, PET, polypropylene or polyethylene. Preferably, the liquid does not 'stick' to the plastic, therefore improving the draining properties of the insert, preferabfy the insert is polypropylene. The insert is created using conventional injection moulding techniques. The gas inlet passage of the insert may be a valve, hole, gas permeable membrane, or other means for allowing gas to enter the insert. See for example, WO 03/039992, WO 01/51367 or GB 2 322 614 for a further discussion of suitable gas inlet passages. The entry of gas into the insert pressurises the insert. Accordingly, the insert need not be pre-pressurised, simplifying manufacture and storage of the insert. Preferably, the gas inlet passage is a one way valve, more preferably, the gas inlet passage is a duckbill type valve. The inlet passage may be a separate component introduced into upper moulding during manufacture, or may be integrally formed with the moulding. The gas inlet passage may be bi-injected during the moulding cycle allowing it to be formed from a different material. Preferably, the inlet passage will be integrally moulded with the upper moulding, and formed from the same material as the upper moulding, thereby reducing the cost of manufacture and assembly of the insert. Further, integral moulding of the inlet passage into the upper moulding removes the need for a separate component which may become detached from the insert, precluding successful operation of the insert upon use, and creating a choking hazard for the user. Most preferably, a duckbill valve is integrally moulded with the upper moulding and arranged to allow gas to enter the chamber.

The gas outlet passage is preferably also a one way valve; typically but not exclusively this valve will be a duckbill valve. The gas outlet passage may also be bi-injected during the moulding cycle allowing it to be foπned from a different material. More preferably, the outlet passage will be integrally moulded with the lower moulding, and fonned from the same material as the lower moulding, offering the same manufacture benefits as outlined above with reference to the upper moulding. Most preferably a duckbill valve is integrally moulded with the lower moulding and arranged to allow gas to be jetted into the beverage. Duckbill valves are designed such that the aperture of the valve may vary with the pressure applied to them. Accordingly, the use of a duckbill valve provides for jetting of the gas and the first liquid into the second liquid at a substantially constant velocity.

In a preferred embodiment the insert is of two piece construction comprising an upper moulding with integrally moulded duckbill valve and a lower moulding with integrally moulded duckbill valve. Duckbill valves are preferred as they cause efficient shearing of the second liquid leading to the production of a smooth creamy head.

To prevent or inhibit leakage of the first liquid from the insert through the gas inlet passage or the gas outlet passage, the valve slit preferably includes one or more frangible straps, or other leakage prevention means. Preferably these will comprise perforations in the valve slit, which remain intact during the filling and assembly of the insert, and during storage in the container, but which in use will break allowing, in the case of the gas inlet passage, equilibration of the pressure in the head space of the pressurised container and the chamber of the insert and in the case of the gas outlet passage, jetting of the first liquid and the gas from the insert upon opening of the container. Leakage of small amounts of the first liquid into the second liquid prior to opening of the container could occur by capillary action within either valve. It is necessary to avoid leakage as this may have undesirable aesthetic effects, or in the case where the first liquid and the second liquid are unstable when combined, could impair the effectiveness of the product. Leakage could also be prevented through the use of wax plugs sealing the valves; clip on plastic plugs which are released upon jetting of the first liquid and gas from the insert, preferably the clips will remain attached to the insert after jetting; silicone sealants; glue; or grease. Preferably however, leakage is prevented through the use of frangible straps on one or both of the gas inlet passage and the gas outlet passage.

In a preferred embodiment, the gas outlet passage may comprise a tubular portion (which need not be circular) having attached to the end remote from the moulding a cap which is releasably attached to the tubular portion, for example by a frangible seal. The cap can be made of e.g. the same material as the tubular portion. The cap is permanently attached to the tubular portion by a tether portion. The cap acts to seal the end of the tubular portion until subject to a pre-detennined internal pressure, at which point the cap releases from the tubular portion to allow release of the first liquid into the second fluid, but nevertheless remains attached thereto by the tether portion.

In a preferred variant of this embodiment, the cap can be attached to the tubular portion in the "closed" position by a fonn of snap-fit mechanism, such as for example discussed elsewhere herein, but being configured to release at a pre-determined internal pressure. In a further preferred embodiment, the gas outlet passage may comprise a tubular portion (which again may not be circular) which is releasably sealed by a stopper. The stopper can be retained in the tubular position by friction fit of the side walls of the stopper against the imier walls of the tubular portion. The stopper can be made out of a different plastics material to the tubular wall; preferred materials for the stopper include for example Neoprene (trademark) or Santoprene (trademark).

The stopper should be tethered to the floating insert so as not to be lost in the second fluid when the first fluid is released; conveniently this can be done by a trailing portion which is attached to the stopper and which trails back into the floating insert, and has retaining features which are too large to pass down the tubular portion, thereby ensuring that the stopper is not released from the floating insert into the second fluid when the first fluid is released. Conveniently the retaining features can have a cross ("X") shape or configuration.

A preferred aspect of the previous two embodiments, is that they may prevent leakage of the first fluid remarkably well. Especially in the case of the latter embodiment with the stopper, this is thought to be because they cope relatively well with the thermal stresses the pressurised container and the floating insert are routinely subjected to, allowing a degree of pressure equalisation between the floating insert and the pressurised container contents, but without actually allowing release of the first fluid until it is intentionally released. In use, the insert is designed to float freely on the surface of the second liquid within a container. The insert is preferably weighted to float on the surface of the second liquid with the gas inlet passage in a headspace above this liquid, and with the gas outlet passage below the liquid surface. Typically, the weight differential will be obtained by manufacturing the lower moulding such that is has a mass greater than the upper moulding. Also, preferably the lower moulding is configured with substantially frusto- conical downward pointing walls adjacent the gas outlet passage, so that substantially all of the first liquid contained in the insert is jetted into the second liquid in use. With such a configuration of lower moulding, little or no first liquid is inadvertently retained in the insert.

Alternatively, the insert may be provided with projections, which engage the sides of the container, to secure the insert in position. This is preferred in embodiments where the container is a bottle.

The gas inlet passage may be designed such that the pressure difference on each side of the passage is required to exceed a pre-determined level for the passage to open. This prevents opening of the gas inlet passage after pressurisation of the insert; in the event that the insert is submerged under the surface of the second liquid the pressure exerted by the second liquid will be less than the internal pressure of the insert thereby preventing the second liquid from leaking into the insert.

Preferably the upper and lower mouldings are snap fitted together after addition of the first liquid. The first liquid may be added to the cavity of either the upper or lower moulding. If the first liquid is added to an inverted upper moulding, the lower moulding is clipped onto the upper moulding. If the first liquid is added to the lower moulding, the upper moulding is clipped thereto. The snap fitting may be a 'tongue and groove' fitting, with one of the peripheral edge of the upper moulding or the peripheral edge of lower moulding comprising the 'tongue' and the other of the peripheral edge of the upper moulding or the peripheral edge of lower moulding comprising the 'groove'. Preferably, however the 'tongue and groove' snap fitting is a bore seal. In the present application the tenn 'bore seal' refers to a 'double tongue and groove' seal whereby each of the upper and lower mouldings have a groove around their periphery for receiving one half of the corresponding groove side wall of the other of the upper or lower moulding. Additionally, each of the upper and lower mouldings will grip the half of the corresponding groove in the other of the upper or lower moulding. This provides a seal which is significantly more rigid and has greater stability than a typical 'tongue and groove' seal.

The volume of the insert chamber is preferably between 1 cm³ and 20 cnϊ\ The volume of the chamber may be altered as appropriate for the size of the container and type of liquid, the second liquid, contained therein. More preferably, the volume of the chamber is approximately 10 cm³.

The first liquid is added to either the upper or the lower moulding prior to snap fitting of the upper moulding to form the chamber of the insert. The volume of the first liquid may be in the range 1 to 80% of the volume of the chamber, although preferably the volume of the first liquid will occupy less than 50% of the volume of the chamber, more preferably less than 20% and most preferably in the range 1% to 10% of the volume of the chamber.

The term 'liquid' as used herein is intended to include any flowable material and includes, for examples, syrups and fine particulate matter.

Typically, the upper moulding of the insert has a generally hemispherical domed shape, and the lower moulding is generally flat. The lower moulding is preferably formed from a thicker material than the upper moulding to maintain the weight differential between these two components. This helps keep the insert floating with the gas inlet passage above the surface of the second liquid and the gas outlet passage below the surface of the second liquid. The inside surface of the lower moulding is preferably shaped to be self draining, i.e. little or none of the first liquid is retained in the insert after use. This allows a minimal amount of liquid to be contained within the insert. Accordingly, the inside surface of the lower moulding is shaped to slope towards the gas outlet passage. This ensures that substantially all of the first liquid is jetted into the second liquid upon use. A similar configuration of components may be seen from EP 1 055 614, which describes a heat sealed insert, whereby the gas inlet passage is positioned at the end of a tube such that the gas inlet valve and the gas outlet valve are in close proximity. The gas inlet passage of the invention may be formed with the gas inlet valve and the gas outlet valve in close proximity, as outlined in EP 1 055 614, or with the gas inlet valve formed directly adjacent to the domed surface of the upper moulding, or at a point interposed between these two positions. Where the gas inlet passage is a duckbill valve, it is preferably formed either as an indent in the surface of the upper moulding or at the distal end of a short pipe extending from the domed surface. This helps to minimise the quantity of material required to manufacture the insert and ensures that there is sufficient space in the chamber of the insert for both the first liquid and the gas.

Preferably, where the gas outlet passage is a duckbill valve, the valve protrudes from the lower moulding of the insert and may be surrounded by a protective skirt.

Where both the gas inlet and outlet passages are duckbill valves, these may be positioned in the assembled insert so that the slits of the valves are aligned, or oriented at any angle to each other.

The pressurised container according to the second aspect of the invention may be any container capable of withstanding an internal pressure of up to about 2000 kPa. Preferably this will be a plastics container, most preferably the container will be a plastics bottle or can. Preferably the intemal pressure will be in the range 1 to 600 kPa, more preferably in the range 200 to 400 kPa.

The plastics container may be made from a coloured or substantially transparent thermoplastic polymer such as PET, PEN, polypropylene or polyethylene. Alternatively the container may be metal, glass or a metal and plastic admixture. Preferably, the contamer is a PET, PEN, polypropylene or polyethylene container, most preferably, the container is fonned from substantially transparent polyethylene terephthalate (PET).

The container will contain the second liquid. Above the second liquid will be a head space containing pressurised gas. The gas may be any inert, non- toxic gas but preferably will be carbon dioxide, nitrous oxide or nitrogen. Most preferably the gas will be nitrogen.

The second liquid may be still or effervescent although preferably the second liquid will be an effervescent liquid, as effervescent liquids exhibit shearing characteristics upon jetting of the gas from the insert to form a head.

Preferably, and especially where the container is a conventional ring pull can, the ring pull of the can and the insert are configured such that the insert cannot pass through the opening of the can. This can be done, for example by making the insert larger than the opening of the can or by providing the insert with a resiliently deformable 'fin' or other protrusion capable of defonnation to fit through an aperture but which returns to it's original shape once inside the cavity of the container preventing removal from the container. Other fonns of container, such as screw topped bottles are specifically contemplated.

An embodiment of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view from the side of the insert of the invention;

Figure 2 is a cross-sectional view from the side of the upper and lower mouldings of the embodiment of Figure 1; Figure 3 is a cross-sectional view from the side of the upper and lower mouldings of an alternative embodiment of the invention;

Figure 4 is a side view of the insert of Figure 1; and

Figure 5 is a side view of the pressurised container of the invention including the insert of Figures 1, 2 and 4; Figure 6 is an enlarged perspective view of the duckbill valve of the invention;

Figure 7 is a cross sectional view of an alternative embodiment of insert according to the invention; and

Figure 8 is a cross sectional view of a further alternative embodiment of insert according to the invention.

Figure 1 shows a cross-section of an assembled insert embodying the invention. The insert 10 is formed from an upper moulding 12 and a lower moulding 14 which snap fit together via a peripheral bore seal 16.

Figure 2 shows the two mouldings 12, 14 prior to addition of the first liquid 18 and snap fit connection.

In this embodiment and with specific reference to Figures 1 and 2, the first liquid 18 is a concentrated solution of food colouring. A first duckbill valve 34 provides a gas inlet passage 20 integrally formed with the upper moulding 12. A second duckbill valve 34a fonns the gas outlet passage 22 and is integrally formed with the lower moulding 14. The gas inlet passage 20 is formed in this embodiment, at the distal end of a short pipe 21 extending from the domed surface of the upper moulding 12. However, as shown in Figure 3, the gas inlet passage 20 may also be formed directly adjacent to the domed surface of the upper moulding 12. This reduces the quantity of material required to manufacture the msert 10 and ensures that there is sufficient space in the chamber 24 of the insert for both the first liquid 18 and the gas. In this embodiment the gas outlet passage 22 is surrounded by a protective skirt 26, however this may be absent in alternative embodiments of the invention. Figure 4 shows a complete assembled insert 10.

Figure 5 depicts a pressurised container 28 ^"according to a second aspect of the invention. In this embodiment the pressurised container 28 is a substantially transparent ring pull polyethylene terephthalate can and contains one insert 10. When filling container 28, the insert 10 containing the first liquid 18 is placed into the container 28 and the container 28 is flushed with inert gas to remove any oxygen from the inside of the container 28. The container 28 is then filled with a second different liquid 30, pressurised with liquid nitrogen and sealed. In this embodiment the second liquid 30 is milk which has been treated to contain an additional gas dissolved in solution, preferably the gas will be carbon dioxide or nitrous oxide. After sealing the liquid nitrogen within the container 28, the increase in pressure causes the gas inlet passage 20 to open and gas from the headspace to enter the chamber 24 of the insert 10. This equilibrates the internal pressure of the insert 10 and the headspace of the container 28. Upon opening container 28, the internal headspace pressure of the container 28 rapidly vents to atmospheric pressure. Accordingly, the internal pressure of the insert 10 is higher than that of the headspace of the container 28, and the first liquid 18 from the insert 10 is jetted into the second liquid 30 via the gas outlet passage 22 causing rapid mixing of the two liquids. This jetting also jets the gas from the insert into the second liquid 30. In this embodiment the mixing of the first liquid 18 and the second liquid 30 causes a colour change in the second liquid 30. Additionally, the jet of gas causes shear in the second liquid 30, leading to foaming of this liquid 30 and the production of a frothy head. Both of these changes in appearance are visible to the user through the clear walls of container 28.

Insert 10 with integral inlet and outlet passages 20, 22 is made from polypropylene. Each of the inlet passage 20 and the outlet passage 22 include an elongate slit 34, 34a defined by lips 36, 38. Use of duckbill valves allows fluid to flow through the elongate slit 34, 34a by forcing the lips apart. Fluid is prevented from flowing in the reverse direction as such flow would cause the lips to be forced together.

The slits 34 and 34a of gas inlet passage 20 and outlet passage 22 include a series of frangible straps 35, shown in Figure 6. The straps 35 are formed by making perforations in the slit 34, 34a which hold the lips 36 and 38 together prior to, for gas inlet passage 20 and slit 34, equilibration of the gas pressure between the headspace of container 28 and the chamber 24 of insert 10 and for gas outlet passage 22 and slit 34a the jetting of the gas and first liquid 18 from the insert 10. The presence of the frangible straps 35 prevents leakage of the first liquid 18 from the insert which could otherwise occur as a result of capillary action, causing small amounts of the first liquid 18 to mix with the second liquid 30 prior to opening of the container 28 by the user. This may have undesirable aesthetic effects, or in the case where the first liquid 18 and the second liquid 30 are unstable when combined, impair the effectiveness of the product. When container 28 is opened the internal pressure of the insert 10 is sufficient to break the frangible straps 35 and allow the gas and first liquid 18 to jet into and mix with the second liquid 30.

Polypropylene inlet and outlet passages 20, 22 are used as polypropylene is more resistant to change in shape as a result of the pressure applied by the gas. Many other thermoplastics, for example TPE, open under pressure to form circular orifices. When jetting gas and liquid 18 polypropylene valves retain substantially their moulded conformation providing improved shear of the product providing a substantially constant jetting velocity in use. Further, manufacture of inserts where the inlet and outlet passages 20, 22 are made from polypropylene is simpler and more efficient as it is possible to fonn the slit 34, 34a directly during the moulding cycle, removing the need for a separate slitting step in the manufacturing process. Lower moulding 14 is made with a greater wall thickness than the upper moulding 12 to ensure that the assembled insert 10 will float with the lower moulding 14, and hence the gas outlet passage 22, in contact with the second liquid 30. Upper moulding 12 has a substantially hemispherical domed shape, and lower moulding 14 is generally configured with substantially frusto-conical downward pointing walls adjacent the gas outlet passage 22, so that substantially all of the first liquid 18 contained in the insert 10 is jetted into the second liquid upon opening of container 28. With such a configuration of lower moulding 14, little or none of first liquid 18 is inadvertently retained in the insert.

The upper moulding 12 and lower moulding 14 each contain shaped grooves 42 on their peripheral edges 44, 46. These grooves 42 snap fit together to form insert 10 with one flange 48 of each groove 42 being received and gripped by the corresponding groove 42 on the other of the upper or lower moulding 12, 14. Accordingly a rigid, stable bore seal 16 is formed from between the upper and lower mouldings 12, 14.

Prior to snap fitting the upper and lower mouldings 12, 14 together the first liquid, 18 is added, in this embodiment, to the lower moulding 14. The volume of liquid required depends upon the specific application, however, in this embodiment approximately 1 cm of liquid is used.

The volume of the chamber 24 of the insert 10 may be varied as appropriate for the volume of the first liquid 18 to be dispensed from insert 10 and the volume of the pressurised container 28 into which the first liquid 18 and the gas are dispensed. In this embodiment however the volume will be approximately 10 cm⁰.

Figure 7 shows an alternative embodiment of insert utilising a different form of gas outlet passage. In this embodiment, the gas outlet passage 22 is elongated somewhat compared to other embodiments. Retained therein by friction fit (although in some embodiments an additional sealant may be utilised between stopper and gas outlet passage) is a stopper 50, which may be made e.g. of synthetic rubber. Stopper 50 has a trailing portion 51, to which is attached retaining feature 52, which when viewed from above is "X" shaped. The dimensions of retaining feature 52 in combination with the rigidity of the materials used to make trailing portion 51 and retaining feature 52 are so as to cause retaining feature 52 to be retained by the insert in use, as retaining feature is not able to pass along outlet passage 22.

In the embodiment of Figure 8, outlet passage 22 is sealed by releasable overcap 60, which is releasably retained thereon, for example by friction fit between edges 61, 62 of overcap 60, on the exterior surface of outlet passage 22, or a snap fit mechanism (not shown). Overcap 60 is tethered to the insert by tether portion 63, which in turn is attached to retaining ring 64 which is non-releasably attached to the exterior surface of outlet passage 22, and is held in place by a stop 65.

Claims

1. A floating insert having a body defining a single chamber containing gas and a first liquid, the floating insert being usable in a pressurised container containing a second liquid which is different from the first liquid, such that when the container is opened the gas and the first liquid are jetted from the floating insert into the second liquid, and mixing of the first and second liquids occurs within the container; the floating insert comprising an upper moulding including a gas inlet passage to allow gas at greater than atmospheric pressure to enter the floating insert from a headspace in the container and equalise in pressure with the headspace, and a lower moulding including a gas outlet passage to allow the gas and the first liquid to be jetted from the insert into the second liquid in the container; wherein the chamber is fonned after addition of the first liquid into one of the lower moulding or the inverted upper moulding, by snap fitting a peripheral edge of the upper or lower moulding onto a peripheral edge of the other of the upper or lower moulding to form the sealed floating insert.

2. The floating insert of claim 1 wherein the gas inlet passage and the gas outlet passage comprise a one way duckbill type valves.

3. The floating insert of claim 1 or claim 2 wherein at least one of the gas inlet passage and the gas outlet passage includes leakage prevention means to prevent or inhibit leakage of the first liquid from the floating insert prior to pressure release

4. The floating insert of claim 3 wherein the leakage prevention means comprises frangible straps attached to the slit of a duckbill valve.

5. The floating insert of any preceding claim wherein the upper moulding snap fits onto the lower moulding via a bore seal.

6. The floating insert of any preceding claim wherein the insert is self draining.

7. The floating insert of any preceding claim wherein the gas outlet passage comprises a tubular portion having attached thereto a releasable cap which is retained by a tether portion.

8. The floating insert of claim 7 wherein the cap is sealed to the tubular portion by a frangible seal.

9. The floating insert of claim 7 wherein the cap is sealed to the tubular portion by a snap fit mechanism.

10. The floating insert of any preceding claim wherein the gas outlet passage comprises a tubular portion releasably sealed by a tethered stopper.

11. A pressurised container including the floating insert of any preceding claim.

12. The pressurised container of claim 11 wherein the container comprises a plastics material.

13. The pressurised container of claim 11 or claim 12 wherein the container is translucent or transparent

14. The pressurised container of any of claims 11 to 13 wherein the first liquid is dye or flavouring.

15. The pressurised container of any of claims 11 to 14 wherein the second liquid is milk.

16. A pressurised plastics drinks can containing one floating insert and milk and having a headspace; the floating insert having a body defining a single chamber containing gas and a food dye and/or flavouring, wherein the floating insert is capable of equilibrating it's internal pressure with that of the headspace such that when the can is opened the gas and the dye and/or flavouring are jetted from the floating insert into the milk, and mixing of the food d}'e and/or flavouring and the milk occurs within the contamer.