GB2284590A - A unit for inclusion in a pressurised fluid container - Google Patents

Abstract

A unit for inclusion in a pressurised fluid container 11 for releasing a substance into the fluid when pressure in the container 19 substantially or suddenly reduced, comprises members 12, 20 defining a chamber 28 of variable volume for storing and then releasing the substance. The member 12 has a portion 13 telescopically slidably received within the member 20 and an end wall 21 with a groove 50 extending around the slidable portion. The groove receives a leading part of the member 20 when the members are telescoped together and may cause the leading end to move out of engagement with the portion 13 as the members are telescoped to provide a passage for the substance. Preferably member 20 carries on spigot 28 a washer 30 with teeth 32 which dig into the wall of member 12 as the members are telescoped to hold them together. Legs 35 may be provided between the remote ends of members 12 and 20 which flex outwardly to contact the wall of container 11 when the members are telescoped. <IMAGE>

Description

"A unit for inclusion in a pressurised fluid container" This invention is concerned with improvements relating to units for inclusion in pressurised fluid containers and particularly to an insert which upon a substantial or sudden reduction in pressure within the container, releases substance into the fluid 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.

According to a first aspect of the invention we provide a unit for inclusion in a pressurised fluid container for releasing a substance into the fluid when pressure in the container is substantially or suddenly reduced, comprising two members together defining a chamber of variable volume for storing the substance and from which chamber the substance is released in response to a substantial or sudden reduction in pressure in the container, wherein one of the members has a portion which is telescopically slidably received within the other of the members and which has an end wall which provides a groove which extends around the slidable portion, and the other member has a leading part which is adapted to be received by the groove when the one and other members are telescoped together.

Preferably the leading part of the other member is flared inwardly into close co-operation with the slidable portion of the one member thus to provide a seal as the members relatively slide.

The groove may be configured or may have within it one or more formations which cause the inwardly flared leading end of the outer member to move out of engagement with the slidable portion as the members are telescoped or compressed together to their maximum extent, to provide a passage for substance in the chamber, to pass to the leading part of the other member. Passage means may be provided, for example comprising one or more channels in the groove to permit the fluid to flow past the leading part into the fluid of the container.

The other member may have a shank which is disposed within the chamber during use, and the shank portion may be provided with gripping means disposed generally around the shank whereby upon reception of the slidable portion of the one member within the other of the members, the gripping means grips or digs into an inside surface of the slidable portion to retain the members captive together.

Preferably the slidable portion of the one member comprises a wall being a single thickness of material.

The shank may extend along a central symmetrical axis of the unit and the gripping means may comprise teeth formations which extend outwardly from the shank towards and into gripping and/or digging engagement with the inside surface of the slidable portion of the one member.

The single wall thickness of the slidable portion may increase from a leading end of the slidable portion so that as the members are telescoped or compressed together, the teeth formations grip or dig into the inside surface of the wall to an increasing extent.

One of other of the members may have a receiving formation and there may be provided leg means adapted to deform to engage an inside surface of the container upon telescopic compressive movement between the members, the leg means comprising a plurality of legs each of which is connected by a hinge part at or adjacent one end thereof, to the other or one member respectively and the free ends of each of the legs being received by the receiving formation of the one or other member, the free ends of the legs each having mutually inter-engaging formations.

The receiving formation may comprise a groove and the inter-engaging formations of the legs may each be received in the groove and may co-operate with one another to retain the other ends of the legs in the receiving formation.

Conveniently, the one ends of the legs are connected to the other of the members at or adjacent to a transversely extending end wall thereof, and the receiving formation is provided on the one member at or adjacent one end thereof, for example adjacent to or by a transversely extending end wall thereof.

One or other of the members may have a receiving formation and there may be provided leg means adapted to deform to engage an inside surface of the container upon telescopic compressive movement between the members, wherein the one ends of the legs are connected to the other of the members at or adjacent to a transversely extending end wall thereof, and the receiving formation is provided on the one member at or adjacent one end thereof, for example adjacent to or by a transversely extending end wall thereof.

One of the members may have a portion which is telescopically slidably received within the other of the members and an end wall, the end wall or an extension thereof comprising a central region and an outer region, the central region being configured to engage an inside surface of an adjacent wall of the container and the outer region being inclined away from the inside surface of the adjacent wall of the container.

Thus where the end wall of the member lies adjacent the inside surface of a bottom wall of the container, any gas which might otherwise become trapped between the unit and the bottom wall of the container, can escape by virtue of the inclined outer region of the end wall of the unit.

Where the inside surface of the container is of convex configuration, the central region of the end wall of the unit or the extension thereof, may be of corresponding concave configuration. The outer region of the end wall of the unit may thus be of generally annular configuration.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side illustrative sectional view through a unit in accordance with the invention in an uncompressed or outwardly telescoped condition; Figure 2 is an illustrative side sectional view of the unit of Figure 1, in a container and in a compressed condition, ie inwardly telescoped to the maximum extent; Figure 3 is a top plan view to an enlarged scale of the unit of Figures 1 and 2 in the uncompressed condition; Figure 4 is an enlarged fragmentary section of part of the unit of Figures 1 and 2 in the uncompressed condition; Figure 5 in an enlarged fragmentary section of another part of the unit of Figures 1 and 2 in its uncompressed condition; ; Figure 6 is an enlarged fragmentary section of the part of the unit of Figures 1 and 2 as shown in Figure 4 but in a compressed condition; and Figure 7 is a fragmentary enlarged side view of part of one of the members of the unit of Figures 1 and 2.

Referring to the drawings, there is shown a unit 10 embodying all aspects of the invention which is intended for inclusion in a pressurised fluid container 11 such as a pressurised drinks container for releasing a substance, for example a pressurised gas such as nitrogen, into the fluid when the pressure in the container 11 is substantially or suddenly reduced by opening the container 11, and thereby exposing the interior of the container 11 to atmospheric pressure.

The unit 10 comprises a first member 12 having a generally hollow tubular portion 13 with generally cylindrical external and internal surfaces 14, 15 respectively, and at one end 16 of the tubular portion 13, a circular chamfered leading end 17 is provided to facilitate receiving the end 16 within a second member 20 of the unit 10.

The wall 13 of the tubular portion 13 of the first member 10 is thus provided by a single thickness of material and is integrally formed with a transversely extending end wall 21 which extends outwardly of the tubular portion 13. The thickness of the wall 13 increases from the leading end 17 to a maximum thickness adjacent the end wall 21. The inside surface 15 of the wall 13 is thus slightly tapered, for a reason hereinafter explained.

The unit 10 comprises a second member 20 which also has a generally hollow tubular portion 22 of a slightly greater diameter than the tubular portion 13 of the first member 12, with a generally cylindrical external and internal surfaces 23 and 24 respectively.

The tubular portion 22 is also provided by a single thickness of material.

At one end 25 of the tubular portion 22 of the second member 20, a slightly inwardly flared and chamfered leading edge part 26 is provided, as can best be seen from Figure 5, so that a seal is provided between the leading edge 26 of the second member 20 and the external generally cylindrical surface 14 of the first member 12 during relative telescoping of the first and second members 12, 20, as hereinafter described. The edge 26 undergoes slight outward compression when the tubular portion 13 of the first member 12 ins inserted into the tubular portion 22 of the second member 20 thereby affording an efficient seal within that tubular portion 13.

The second member 20 also has at its other end to leading edge 26, a transversely extending end wall 27.

The first and second members 12, 20, thus provide between them a chamber 28 for storing substance, the volume of which is variable depending upon the relative telescoped positions of the first and second members 12, 20.

The second member 20 comprises a spigot 29 which extends inwardly of the chamber 28 from the end wall 27 thereof generally along the cylindrical axis A of the second member 20. The spigot 29 is of a generally cruciform configuration in section and is tapered so that it is of greatest dimension closest to the end wall 27.

The spigot 29 has attached to its free end, a washer 30 which has a central aperture 31 by which it is attached to a reduced diameter part P of the spigot 29, and a plurality, in this example four, outwardly projecting teeth elements 32.

As the first and second members 12, 20 are telescoped together, ie the unit 10 is compressed, the teeth elements 32 each grip and/or dig into the internal generally cylindrical surface 15 of the tubular portion 13 of the first member 12 thus to maintain the first and second members 12, 20, in engagement with each other. By virtue of the wall 13 of the tubular portion of the first member 12 increasing in thickness towards end wall 21, and the generally cylindrical surface 15 tapering, as the members 12, 20, are compressed together, the teeth elements 32 dig into and grip the surface 15 to an increasing extent. In practice, the washer 30 being inclined slightly towards the end wall 27 of the second member 20, rather than the teeth elements 32 extending perpendicularly to the cylindrical axis A of the unit 10 as illustrated in Figure 1.

Formed integrally with the end wall 27 of the second member 20, are leg means comprising a plurality of flexible legs 35, twelve in this example. Each leg 35 is attached to the end wall 27 by a hinge part 36 and at its opposite free end, each leg 35 is provided with an inter-engaging formation 37 (see Figure 7) comprising a formation enlarged compared with the remainder of the leg 35. The formations 37 each comprise on one side, a tongue 39 of generally triangular configuration, and on an opposite side, a recess 40 again of generally triangular configuration, adapted to receive a tongue 39 of the next adjacent leg 35.

The formations 37 of all of the legs 35 are adapted to be received by a receiving formation of the first member 12, provided by end wall 21 and comprising a continuous groove 41 around the outside of the tubular slidable portion 13. The tongues 39 and recesses 40 of each of the legs 35 co-operate with the recesses 40 and teeth 39 of adjacent legs in the groove so that the legs 35 are all retained by their formations 37 in engagement with each other, the inter-engaging formations 37 providing a continuous ring of material of substantially the same diameter as the groove 41.

Intermediate the hinge parts 36 and the inter-engaging formations 37, the legs 35 comprise a plurality of sections 45, 46, 47 and 48 which are at least flexible relative to one another, to permit the legs 35 by bulging outwards as hereinafter described, to grip the inside of the container 11 in which the unit 10 is received in use.

In use, the first and second members 12, 20 are provided initially as separate components. The interiors of the hollow tubular portions 13 and 22 of the respective first and second members 12, 20 are purged of air or the like in conventional manner,for example under the action of a pressurised nitrogen gas jet.

Immediately after the purging, whilst the interiors of the members 12 and 20 are still occupied by the pressurised nitrogen gas, they are brought together to the condition shown in Figure 1 in which the leading edge 26 of the second member 20 is forced outwardly to provide a seal with the external surface 14 of the tubular portion 13 of the first member 12. The interengaging formations 37 of the legs 35 are received in the receiving formation or groove 41 of the first member 12.

At this stage, the chamber 28 is at a maximum volume and thus contains nitrogen gas. The members 12, 20 may then be compressed or slid telescopically closer together through a predetermined extent and the members 12, 20 are maintained together by the action of the teeth elements 32 and the internal surface 15 of the tubular portion 13 of the first member 12, even though the pressure of the gas in the chamber 28 will be above ambient pressure. Some outward bulging of the legs 35 may occur at this stage.

The unit 10 may then be positioned within a container 11 with which it is intended to be used. In the present example, the container 11 is a beverage can such as a beer can but the container 11 may be any other suitable container such as a bottle made of glass or plastics material, with the unit 10 and the legs 35 being appropriately dimensioned to suit the internal configuration of the container 11, and the desired volume of substance to be dispensed from the unit 10.

When the assembled unit 10 has been inserted into an empty fluid container 11, and telescopically compressed to a desired predetermined extent so as to achieve an initial compression of the nitrogen gas in the interior chamber 28 of the unit 10, the interior of the container 11 into which the unit 10 has been inserted is purged of air of the like, for example under the action of a jet of compressed nitrogen gas, and the fluid to be stored in the container eg beer is then admitted into the container 11 and the container sealed in conventional manner.The container 11 thus containing the unit 19 and the fluid which is pressurised by virtue of containing nitrogen, carbon dioxide or the like in solution, is subjected to a pasteurising operation involving substantial heating of the container 11, the result of which is that any residual nitrogen purging gas in the container 11 or gases that have dissolved in the fluid in the container 11, for example beverage, become heated and thereby increase the pressure within the container 11.The effect of this pressure increase is to force the first and second members 12 and 20 telescopically to compress further to the position shown in Figure 2 when the leading edge 26 of the tubular portion 22 of the second member will be received in a groove 50 provided by the end wall 21 around and adjacent to the tubular portion 13 of the first member 12, radially inside the groove 41 which receives the inter-engaging formations 37 of the legs 35.

The groove 50 comprises at least one, but preferably a plurality of discrete positions around the slidable portion 13, a channel C. In this example, four such channel formations C are provided. Also, the groove 50, at the bottom is of a slightly wedged configuration. Consequently, as the first and second members 12 and 20 are compressed together to their full extent, as seen in Figure 2, the leading edge 26 will be urged away from the wall 13 of the slidable portion, so that a small gap G is provided between the external surface 14 of wall 22 around substantially the entire periphery of the wall 13. Thus passages will be provided along the gap G, and past the leading edge 26 of the wall 22, through the channels C.

At the end of pasteurisation, the pressure in the beverage in the container 11 and in chamber 28 are substantially equal. As the can cools, the pressure in the beverage drops somewhat, while still remaining substantially above atmospheric. The pressure within the chamber 28 tends to equalise with that in the beverage by escape of gas between the leading edge 26 and the wall 13.

The final compression of the members 12, 20 also causes the legs 35 to occupy the positions shown in Figure 2 where at least the sections 46 of the legs 35, engage the inside surface of the side wall of the container 11, and as a result, the unit 10 is securely held in the container 11, preferably adjacent the bottom wall 52 thereof.

It can be seen that the end wall 21 of the first member 12 in use, lies adjacent the bottom wall 52 of the container 11.

The bottom wall 52 of the container 11 has a domed or convex configuration so as to add rigidity to the container 11 which is only a thin walled metal can.

The undersurface 53 of the end wall 21 of the unit 10 has a central region 54 which is of a concave configuration corresponding closely to the convex configuration bottom wall 52 of the container 11. Thus the end wall 21 sits substantially with the central region 54 of the undersurface 53 in contact with the bottom wall of the container 11.

The undersurface 53 of the end wall 21 of the unit 10 also comprises a second generally annular region 55 which comprises a substantially planar surface which is inclined upwardly away from the bottom wall 52 of the container 11. Thus in the event that any gas is trapped between the unit 10 and the container 11, this gas may easily escape from beneath the unit 10 without causing dislodgement of the unit 10, particularly before final compression when the legs 35 firmly hold the unit 10 with respect to the container 11. Also, by virtue of the legs 35 being attached by hinge parts 36 to the end wall 27 of the second member 20, no trap for gas is provided beneath the end wall 27.

When the unit 10 is fully compressed to its Figure 2 position, the teeth elements 32 will retain the members 12, 20 in their fully compressed condition. At this stage, the pressure of the gas in chamber 28 will be generally the same as in container 11.

When the container 11 is opened so as to expose the initially pressurised fluid content of the container to atmospheric pressure, the pressure of the gas within the chamber 28 of the unit, is sufficiently greater than atmospheric pressure, for gas to be forced from the chamber 28 into the gap G between the tubular formations 13 and 22 of the first and second members 12, 20, downwardly towards the leading edge 26 of the second member 20 through the channels C into the fluid contents of the can. The number of and dimensions of the channel formations C are carefully arranged to release the gas from chamber 28 at a controlled rate.

The release of the compressed nitrogen into the fluid, such as beverage, has the effect of causing the formation of a head or "frothing" of the beverage.

If desired, some movement of the spigot 29 relative to the washer 30 may be permitted such that upon the substantial or sudden release of pressure within the container 11, the first and second members 12 and 20 are permitted to move apart from the fully compressed telescopic position a small amount, to facilitate the escape of pressurised gas from the chamber 28 into the fluid content of the container 11.

Of course if desired, substances other than pressurised nitrogen gas may be stored in the unit 10, and the container 11 may comprise another flux to beverage or beer as described in this specification.

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

Claims (16)

1. A unit for inclusion in a pressurised fluid container for releasing a substance into the fluid when pressure in the container is substantially or suddenly reduced, comprising two members together defining a chamber of variable volume for storing the substance and from which chamber the substance is released in response to a substantial or sudden reduction in pressure in the container, wherein one of the members has a portion which is telescopically slidably received within the other of the members and which has an end wall which provides a groove which extends around the slidable portion, and the other member has a leading part which is adapted to be received by the groove when the one and other members are telescoped together.

2. A unit as claimed in Claim 1, wherein the leading part of the other member is flared inwardly into close co-operation with the slidable portion of the one member thus to provide a seal as the members relatively slide.

3. A unit as claimed in Claim 1 or Claim 2, wherein the groove is configured or has within it one or more formations which cause the inwardly flared leading end of the outer member to move out of engagement with the slidable portion as the members are telescoped or compressed together to their maximum extent, to provide a passage for substance in the chamber, to pass to the leading part of the other member.

4. A unit as claimed in Claim 3, wherein passage means are provided, comprising one or more channels in the groove to permit the fluid to flow past the leading part into the fluid of the container.

5. A unit as claimed in any one of the preceding Claims, wherein one member may have a shank which is disposed within the chamber during use, and the shank portion is provided with gripping means disposed generally around the shank whereby upon reception of the slidable portion of the one member within the other of the members, the gripping means grips or digs into an inside surface of the slidable portion to retain the members captive together.

6. A unit as claimed in any one of the preceding Claims, wherein the slidable portion of the one member comprises a wall being a single thickness of material.

7. A unit as claimed in Claim 5 or 6, wherein the shank extends along a central symmetrical axis of the unit and the gripping means comprises teeth formations which extend outwardly from the shank towards and into gripping and/or digging engagement with the inside surface of the slidable portion of the one member.

8. A unit as claimed in Claim 7, when dependent on Claim 5, wherein the single wall thickness of the slidable portion increases from a leading end of the slidable portion so that as the members are telescoped or compressed together, the gripping means grip or digs into the inside surface of the wall to an increasing extent.

9. A unit as claimed in any one of the preceding Claims, wherein one or other of the members has a receiving formation and there are provided leg means adapted to deform to engage an inside surface of the container upon telescopic compressive movement between the members, the leg means comprising a plurality of legs each of which is connected by a hinge part at or adjacent one end thereof, to the other or one member respectively and the free ends of each of the legs are received by the receiving formation of the one or other member, the free ends of the legs each having mutually inter-engaging formations.

10. A unit as claimed in Claim 9, wherein the receiving formation comprises a groove and the inter-engaging formations of the legs can each be received in the groove and may co-operate with one another to retain the other ends of the legs in the receiving formation.

11. A unit as claimed in Claim 9 or 10, wherein the one ends of the legs are connected to the other of the members at or adjacent to a transversely extending end wall thereof, and the receiving formation is provided on the one member at or adjacent one end thereof, for example adjacent to or by a transversely extending end wall thereof.

12. A unit as claimed in any one of Claims 1 to 8, wherein one or other of the members has a receiving formation and there being provided leg means adapted to deform to engage an inside surface of the container upon telescopic compressive movement between the members, wherein the one ends of the legs are connected to the other of the members at or adjacent to a transversely extending end wall thereof, and the receiving formation is provided on the one member at or adjacent one end thereof, for example adjacent to or by a transversely extending end wall thereof.

13. A unit as claimed in any one of the preceding Claims, wherein one of the members has a portion which is telescopically slidably received within the other of the members and an end wall, the end wall or an extension thereof comprising a central region and an outer region, the central region being configured to engage an inside surface of an adjacent wall of the container and the outer region being inclined away from the inside surface of the adjacent wall of the container.

14. A unit as claimed in Claim 13, wherein the end wall of the member lies adjacent the inside surface of a bottom wall of the container, any gas which might otherwise become trapped between the unit and the bottom wall of the container, can escape by virtue of the inclined outer region of the end wall of the unit.

15. A unit as claimed in Claim 13 or 14, wherein the inside surface of the container is of convex configuration, the central region of the end wall of the unit or the extension thereof, is of corresponding concave configuration, the outer region of the end wall of the unit can be of generally annular configuration.

16. A unit substantially as hereinbefore described with reference to the accompanying drawings.