GB2305158A - A froth-generating insert for a container (e.g. a can of beer), a container incorporating the insert, and a method of filling the container - Google Patents

Abstract

A froth-generating insert 10 for a container 20 has a chamber with a first opening 15 in an upper part 14 and a second opening 30 in a lower part 25. The first opening 15 may have a configuration whereby surface tension prevents gas escaping from the chamber prior to the container being opened. The insert may have a cap part 12 which snap fits onto a body part 11. The insert may be held in the container by locating means which may be at least two mounting arms 17 with arcuate flanges 18. The mounting arms may be hinged and can move between a retracted position so that the insert can pass through a restricted mouth 51, and an extended position for engagement with the container walls. In two further embodiments, a container 20 is provided with an insert 10, and a method of filling and sealing is used to flush the insert with non-oxidising gas and then pressurise the container during pasteurisation so that some beverage enters the chamber of the insert. When the container is opened, gas escapes from the first opening in preference to the second opening to generate froth in the beverage.

Description

Title: "Insert" Description of Invention This invention relates to inserts for inclusion in containers for liquid under pressure and in particular to inserts which, upon a reduction in pressure within the container when the container is opened, releases substance such as gas into the liquid content of the container, particularly, but not exclusively, to have the effect of causing the formation of a head or frothing of the content of the container.

For example, inserts for inclusion in cans of beer or other beverage subjected to a pressure above atmospheric pressure within the interior of the can with the intention of forming a head, or an enhanced head, of froth, preferably of a creamy nature on beer or other beverage by a jet of gas from the insert.

There have been prior proposals to form, or enhance the formation of such a head, examples are: EP-A-227213, WO-A-91/07326, WO-A-92/00896, WO-A-93/248324.

Objects of the invention are to provide a new or improved insert for inclusion in pressurised fluid containers and to provide a container having such an insert therein and to provide a method of producing a closed container having such an insert therein.

According to one aspect of the present invention, we provide an insert, for inclusion in a container for liquid under pressure, for releasing a substance into the liquid from the insert when the pressure in the container is reduced, comprising a chamber having a first opening to provide a connection between the interior of the chamber and the exterior of the chamber at an upper part of the insert and a second opening to provide a connection between the interior of the chamber and the exterior of the chamber at a lower part of the insert.

The first opening may be provided in an upper wall of the insert and provide communication through the upper wall between external and internal surfaces of the upper wall and the second opening may be provided in a lower wall of the insert and provide communication through the lower wall between external and internal surfaces of the lower wall.

The insert may be provided with locating means to permit the insert to be located in a predetermined orientation relative to the container.

At least said first opening may have a configuration whereby surface tension of the liquid in the container prevents egress of gas from the container therethrough when the pressure differential between the interior of the chamber and the exterior of the chamber is below a predetermined level.

The first opening may have a minimum dimension at the outer end of the opening, i.e. the end of the opening which is, in use, in contact with the liquid in the container.

The first opening may be of circular cross-section at said outer end.

The first opening may have a cylindrical portion extending from said outer end.

The first opening may have a frusto-conical portion diverging from the cylindrical portion at the end thereof remote from said outer end.

The first opening may have a further frusto-conical portion diverging from the larger diameter end of the frusto-conical portion.

The first opening may have a cylindrical portion extending from the larger diameter end of the further frusto-conical portion.

The second opening may have a configuration whereby gas flows from the interior of the chamber through the first opening in preference to egress of liquid through the second opening.

The second opening may have a minimum dimension at the outer end of the opening, i.e. the end which is, in use, in contact with the liquid in the container.

The second opening may be of circular cross-section at said outer end.

The second opening may have a cylindrical portion extending from said outer end.

The second opening may have a frusto-conical portion diverging from the cylindrical portion at the end thereof remote from said outer end.

The insert may comprise a cup shaped body part having a side wall and a cap part which is a snap fit on the body part, for example, by virtue of a radially outwardly extending rib formation provided on the body part and an undercut or recess in a skirt which extends from the cup part to overlap an end portion of the side wall of the body part.

The insert may comprise a housing in which is provided said chamber and the housing may be provided with at least two mounting arms which are moveable relative to the housing between a retracted position in which the arms project from the housing to a smaller extent than they project in an extended position in which part of each arm is adapted to engage the container to mount the insert in the container.

When the arms are in their retracted position they may be passed through a restricted neck of the container and then moved to their extended position after having been passed through the restricted neck to engage, for example, a side wall of the container.

At least one of the arms may be of generally part annular or frustosector shape with the outer periphery being of a diameter adapted to conform at least generally with the interior of the container in which the insert is intended to be used.

The outer periphery of the arm may be provided with a flange which may extend in a direction towards the open mouth of the container when the insert is disposed in the container.

Said at least one arm may be hinged to the housing at a position adjacent the housing.

The at least one arm may be provided with a line of weakening adjacent to and spaced outwardly of the position of connection of the arm to the housing.

The at least one arm may be configured so as to be resiliently deformable from said extended position to said retracted position so as to move from the retracted position to the extended position automatically when disposed within the can as a result of said resilient bias.

According to a second aspect of the present invention we provide a sealed container, having a base and a top, in which an openable closure is provided to permit the contents of the container to be dispensed, and the container having therein a liquid such as a beverage and an insert according to the first aspect of the invention with the insert oriented so that said first opening is closer than is the second opening to the top of the container.

The container and its contents may have been subjected to a pasteurising operation in which liquid has entered the chamber through at least one of said openings.

The container may be stored in a top uppermost position in which the liquid in the chamber covers the inner end of the second opening and the pressure difference between the interior and the exterior of the chamber and the surface tension of the liquid in the container prevents said egress of gas from the interior of the chamber through the first opening.

According to a third aspect of the invention we provide a method of filling and sealing a container comprising the steps of inserting an insert according to a first aspect of the invention and containing a gas into the container, filling the container with liquid and sealing the container, subjecting the filled container to a subsequent pasteurisation operation in which the container is heated, the pressure therein thereby being increased above atmospheric pressure to cause liquid to enter the chamber through at least one of said openings whereby, when the container is stored in an upright position egress of gas from the interior of the chamber is prevented or resisted by the surface tension of the liquid on the exterior of the chamber and, when the container is opened to reduce the pressure inside the container, the resultant pressure differential between the interior and the exterior of the chamber overcomes the surface tension and gas flows out of the first hole in preference to egress of liquid through the second hole.

The method may include the step of flushing air from the interior of the insert with nitrogen, carbon dioxide or other non-oxidising gas.

Said flushing step may be performed after the insert has been introduced into the container or prior to the insert being introduced into the container.

A embodiment of the invention will now be described by way of example with reference to the accompanying drawings, wherein: FIGURE 1 is a longitudinal cross-section through a container having an insert disposed therein embodying the invention; FIGURE 2 is an end view of the insert of Figure 1; FIGURE 3 is a fragmentary cross-sectional view, to an enlarged scale, of a first opening of the insert of Figures 1 and 2; and FIGURE 4 is a cross-sectional view to a similar enlarged scale of a second opening of the insert of Figures 1 and 2.

Referring to the Figures, an insert is shown at 10 and comprises a body part 11 and a cap part 12 which are made, in the present example, by injection moulding in a suitable synthetic plastics material such as polypropylene.

The body part 11 comprises a cylindrical side wall 13 and a circular flat disc shaped end wall 14. The end wall 14 has a first opening 15 therethrough disposed centrally of the end wall 14 and of a configuration hereinafter to be described with reference to Figure 3.

The body part 11 is provided with a pair of arms 16 each of which comprises a generally part-annular or frusto-sector shape 17 having an upstanding flange 18 at their outer ends for engagement with a cylindrical wall 19 of a conventional container 20. At their inner ends the part-annular parts 17 are connected by a reduced thickness portion 21 to a pair of opposed diametrically extending portions 22 moulded intregrally with the wall 13.

The cap part 12 has a transversely extending wall part 25 of generally circular flat disc configuration having a peripheral skirt 26 which overlies an end portion of the side wall 13 and which is provided with an undercut or recess 27 which snap fits with an outwardly extending rib 28 at the free end of the wall 13 to retain the cap and body parts together in gas tight relationship.

If desired, a suitable sealant and/or adhesive may be provided between the cap and body parts to ensure that the parts are thus retained in gas tight relationship.

The wall part 25 has a second opening 30 disposed centrally thereof, to be described in more detail hereinafter with reference to Figure 4.

Referring now to Figure 3, the first opening 15 is provided in a tubular boss 31 which depends downwardly from the internal surface of the wall 14 and which is moulded with a first frusto-conical portion 32 which in the present example has an included angle of 31 but which may vary and which diverges in the direction away from the exterior of the chamber. At the larger diameter end of the portion 32 is a second frusto-conical portion 33 which in the present example has an included angle of 8" but which may vary. At the larger diameter end of the second frusto-conical portion 33 is a cylindrical portion 34 having a diameter of, in the present example, 1.4mm but which may vary.

At its smaller diameter end the first frusto-conical portion 32 has a diameter of, in the present example, 0.4mm but which may vary.

At the smaller diameter end of the first frusto-conical portion 32 is an outer portion 35 of the opening which, in the present example, is made by drilling through the wall 14 centrally of the hereindescribed portions 32, 33, 34. In the present example the outer portion 35 is cylindrical and has a diameter of 0.24mm but may vary, generally from about 0.25mm or smaller but may be larger. The precise size depends on the viscosity and surface tension of the beverage and could be determined empirically for the beverage concerned.

The above described dimensions and configuration are chosen so as to ensure that the surface tension of the beverage in the container is such that, at the pressure differential obtaining during storage of the container, gas from within the container cannot egress through the opening 15.

Referring now to Figure 4, the second opening 30 comprises a moulded frusto-conical part 40 having a smaller diameter end towards the outside of the chamber and having an included angle. At its larger diameter end the frusto-conical portion 40 has a diameter of 0.68mm whilst at its smaller diameter end it has a diameter of 0.40mm. At the smaller diameter end of the frustoconical portion 40 is an outer portion 41 of the opening 30 which is of cylindrical configuration and made, in the present example, by moulding in the wall 25 in line with the axis of the frusto-conical portion 40. It has a diameter of 0.24mm.

The container 19 is shown in chain dotted line and in the present example is a conventional beer can made of pressed aluminium of conventional shape having a generally dome shaped base wall 50 and an open mouth 51 which is of smaller cross-section than the cross-section of the main cylindrical wall 19 of the container.

The cap part 12 of the insert has a downwardly depending skirt 52 of cylindrical configuration adapted to fit on the dome shaped base wall 50 of the container and having a pair of diametrically opposed part circular cut-outs 53 to permit flow of beverage therethrough.

In use, an insert 10 can conveniently be assembled together from the body and cap parts off site and transported to the can filling line as desired. The insert contains air at ambient pressure and thus can be transported and stored for any desired period of time.

Such an insert is then introduced into the interior of the container 19 through the mouth 51 with the arms 16 being deflected towards the dotted line position shown in Figure 1 to permit passage of the insert through the mouth 51.

The insert is carried on a suitable insertion machine and the insert is moved until the skirt 52 engages the bottom wall 50 of the container. Once the arms 16 have moved passed the restricted mouth 51 they can spring out to an extended position and/or, and as preferred in this example, they can be acted upon by a driving member, comprising a sleeve having a diameter less than the diameter of the mouth 12 and provided on the insertion apparatus, which acts upon the arms to move them to a final extended position as shown in full line in Figure 1 to mount the insert in the container with the skirt 50 firmly engaging the internal surface of the bottom wall 50 of the container.

A probe, which may be part of the insertion apparatus or a separate component, is then brought into sealing engagement with the wall 14 around the aperture 15 and the interior of the insert is then flushed with nitrogen to remove the air and in particular to remove oxygen from the air so that no oxidising gas remains in the insert sufficient deleteriously to affect the beverage to be stored in the can. The nitrogen is introduced into the chamber of the insert through the first opening 15 and air and nitrogen leave the insert through the second opening 30. This operation is carried out until adequate flushing has been performed to reduce the oxidising gas content of the insert to a desired level. In the present example this flushing of nitrogen through the insert also causes the container itself to be similarly flushed with nitrogen which is passed through the insert. If desired, however, the container may be flushed with nitrogen separately from the insert.

Furthermore, other non-oxidising gas such as carbon dioxide may be used to flush the insert and/or the container.

The container 19 is then filled with beverage such as beer and a dose of liquid nitrogen is added and a lid is fitted and sealed to the upper end 51 of the container in conventional manner. The nitrogen gas in the insert is at atmospheric pressure after flushing and substantially at atmospheric pressure during the filling and can sealing operations.

The can containing the beverage may at this stage be inverted and since the pressure inside the insert is substantially the same as the pressure outside the insert and because of the small diameter of the openings 15 and 30 surface tension of the beverage in the container ensures that the nitrogen gas is retained in the container and beverage does not enter the container irrespective of the orientation of the can.

The thus filled and sealed container is then subjected to a conventional pasteurising operation where the can is heated to an elevated temperature of, for example 60 to 650C which causes the pressure inside the container to increase to, for example 4 to 6 bar and this causes beer or other beverage in the container to enter the interior of the insert through at least one of the openings 15 and 30.

The amount of beer which enters the insert is relatively small and forms a layer having a depth of typically 1 to 3mm but in any event such as to cover the second opening 30 when the can is in a normal upright position resting on a base rib 54 formed on the bottom wall of the container and with the top closure which has an openable closure, for example by means of a ring pull, uppermost and through which beverage can be dispensed when the can is subsequently opened. After pasteurisation the pressure within the container falls but remains above atmospheric pressure, for example at a pressure of about 2 bar.The pressure of the nitrogen in the insert and of the beverage in the container externally of the insert is the same, and the surface tension of the beverage prevents, or at least substantially resists, gas exiting from within the insert through the first opening 15, whilst the layer of beverage within the insert prevents, or at least substantially resists, gas exiting through the second opening 30.

The can can be thus stored for any normal length of time and may be refrigerated or stored at ambient temperature as desired.

When the closure is opened, for example by pulling the ring pull, the pressure inside the container is reduced to atmospheric pressure and thus the nitrogen within the insert is then at a relatively high pressure differential so that the gas escapes through the first opening 15 in preference to pushing beverage out through the second opening 30. The gas thus flowing through the first opening 15 aids the formation of a head in conventional manner.

Although the substance released when the can is opened is gas, if desired other substance may be released.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (36)

1. An insert for inclusion in a container for liquid under pressure, for releasing a substance into the liquid from the insert when the pressure in the container is reduced, comprising à chamber having a first opening to provide a connection between the interior of the chamber and the exterior of the chamber at an upper part of the insert and a second opening to provide a connection between the interior in the chamber ancl the exterior of the chamber at a lower part of the insert.

2. An insert according to Claim 1 wherein the first opening is provided in an upper wall of the insert and provides communication through the upper wall between external and internal surfaces of the upper wall and the second opening may be provided in a lower wall of the insert to provide communication through the lower wall between external and internal surfaces of the lower wall.

3. An insert according to Claim l or Claim 2 wherein said insert is provided with locating means to permit the insert to be located in a predetermined orientation relative to the container.

4. An insert according to any one of the proceeding Claims wherein said first opening has a configuration whereby surface tension of the liquid in the container prevents egress of gas from the container therethrough when the pressure differential between the iiiterior of the chamber and the exterior of the chamber is below a predetermined level.

5. An insert according to any one C)f the preceding Claims wherein the first opening has a minimum dimension at the outer end of the opening, i.e., the end of the opening which is, in use, in contact with the liquid in the container.

6. An insert according to Claim 5 wherein the first opening is of circular cross section at said outer end.

7. An insert according to Claim 6 wherein the first opening has a cylindrical portion extending from said outer end.

8. An insert according to Claim 7 where the first opening has a frustoconical portion diverging from the cylindrical portion at the end thereof removed from said outer end.

9. An insert according to Claim 8 wherein the first opening has a further frusto-conical portion diverging from the larger diameter end of the frusto-conical pOrtiOn.

10. An insert according to Claim 9 wherein the first opening has a cylindrical portion extending from the larger diameter end of the further frustoconical portion.

11. An insert according to any one of the preceding claims wherein the second opening has a configuration whereby gas flows from the interior of the chamber through the first opening in preference to egress of liquid through the second opening.

12. An insert according to any one of the preceding claims wherein the second opening has a minimum dimension at the outer end of the opening, i.e., the end which is, in use, in contact with the liquid in the container.

13. An insert according to Claim 12 wherein the second opening is of circular cross section at said outer end.

14. An insert according to Claim 13 wherein the second opening has a cylindrical portion extending from said outer end.

15. An insert according to Claim 14 wherein the second opening has a frusto-conical portion diverging from the cylindrical portion at the end thereof remote from said outer end.

16. An insert according to any one of the preceding claims wherein the insert comprises a cup shaped body part having a side wall and a cap part which is a snap fit on the body part.

17. An insert according to Claim 16 wherein the cap part is a snap fit on said body part by virtue of a radially outwardly extending rib formation provided on the body part and an under cut or recess in a skirt which extends from the cup part to overlap an end portion of the side wall of the body part.

18. An insert according to any one of the preceding claims wherein the insert comprises a housing in which is provided said chamber.

19. An insert according to Claim lE wherein the housing is provided with at least two mounting arms which are moveable relative to the housing between a retracted position in which the arms project from the housing to a smaller extent than they project in an extended position in which part of each arm is adapted to engage the container to mount the insert in the container.

20. An insert according to Claim 19 wherein, when the arms are in their retracted position, said housing may be passed through a restricted neck of the container.

21. An insert according to Claim 20 wherein said arms may move to their extended position after having been passed through the restricted neck to engage a side wall of the container.

22. An insert according to any one of Claims 19 to 21 wherein at least one of said arms may be of generally part annular or frustosector shape with the outer periphery being of a diameter adapted to conform at least generally with the interior of the container in which the insert is intended to be used.

23. An insert according to Claim 22 wherein the outer periphery of the arm may be provided with a flange which may extend in a direction towards the open mouth of the container when the insert is disposed in the container.

24. An insert according to Claim 22 or Claim 23 wherein said at least one arm may be hinged to the housing at a position adjacent the housing.

25. An insert according to Claim 22 or Claim 23 wherein said at least one arm may be provided with a line of weakening adjacent to and spaced outwardly of the position of connection of the arm to the housing.

26. An insert according to any one of Claims 22 to 25 wherein the at least one arm is configured so as to be resiliently deformable from said extended position to said retracted position so as to move from the retracted position to the extended position automatically when disposed within the can as a result of said resilient bias.

27. An insert substantially as described hereinbefore with reference to the accompanying drawings.

28. A sealed container having a base and top, in which an openable closure is provided to permit the contents of the container to be dispensed, and the container having therein a liquid such as a beverage and an insert according to any one of Claims 1 to 27 with the insert oriented so that said first opening is closer than the second opening to the top of the container.

29. A sealed container according to Claim 2(S wherein the container and its contents have been subjected to a pasteurising operation in which liquid has entered the chamber through at least one of said openings.

30. An insert according to Claim 28 or Claim 29 wherein the container is stored in a top uppermost position in which the liquid in the chamber covers the inner end of the second opening and the pressure difference between the interior and the exterior chamber and the surface tension of the liquid in the container prevents said egress of gas through the interior of the chamber through the first opening.

31. A sealed container substantially as hereinbefore described with reference to the accompanying drawings.

32. A method of filling and sealing a container comprising the steps of inserting an insert, according to any one of claims 1 to 27 and containing a gas, into the container, filling the container with liquid and sealing the container, subjecting the filled container to a subsequent pasteurisation operation in which the container is heated, the pressure therein thereby being increased above atmospheric pressure to cause liquid to enter the chamber through at least one of said openings whereby, when the container is stored in an upright position egress of gas from the interior of the chamber is prevented or resisted by the surface tension of the liquid on the exterior of the chamber and, when the container is opened to reduce the pressure inside the container, the resultant pressure differential between the interior and the exterior of the chamber overcomes the surface tension and gas flows out of the first hole in preference to egress of liquid through the second hole.

33. A method according to Claim 32 wherein the method includes the step of flushing air from the interior of the insert with nitrogen, carbon dioxide or other non-oxidising gas.

34. A method according to Claim 33 wherein said flushing step may be performed after the insert has been introdLlce(l into the container or prior to the insert being introduced into the container.

35. A method of filling and sealing a container substantially as hereinbefore described with reference to the accompanying drawings.

36. Any novel feature or novel combination of features disclosed herein and/or illustrated in the accompanying drawings.