WO1994022730A1

WO1994022730A1 - Beverage frothing device

Info

Publication number: WO1994022730A1
Application number: PCT/GB1994/000729
Authority: WO
Inventors: Alexander Richard Dunn; David Neil Wragg; Graham Court
Original assignee: Scottish & Newcastle Plc
Priority date: 1993-04-07
Filing date: 1994-04-05
Publication date: 1994-10-13
Also published as: AU6384994A

Abstract

A device for inclusion in a pressurised beverage container for releasing a gas into the fluid in response to a depressurisation of the fluid caused by opening of the container. The device has first and second body members (10, 12) each in the form of an open ended cylinder defined by a circumferential side wall (16, 20) and an end wall (18, 22). The first and second body members (10, 12) being nestable together to define a closed cylindrical chamber (24). One-way motion means (26) provided on one of said body members (10) are adapted to engage the other of said body members (12) in such manner as to permit sliding compressive movement while preventing sliding movement apart of the body members (10, 12). The body members (10, 12) being provided with fluid control means (52) in the form of a deformable free edge of one of the members which, in response to a predetermined decrease in pressure external to the device, defines a conduit (56) through which fluid may exit said chamber (24) through one or more openings of predetermined size.

Description

BEVERAGE FROTHING DEVICE

This invention relates to pressurised fluid containers such as cans for beer and soft drinks.

A number of devices are available for insertion in beverage cans to produce a creamy head on the beverage when dispensed. Many of these rely on the device having a closed chamber containing gas, typically nitrogen, and means responsive to the pressure drop in the beverage when the can is opened to cause the gas to be ejected through a restricted orifice into the beverage to induce the formation of fine bubbles in the beverage. Typically, a pressure responsive valve is used to release the gas. An alternative approach used in a device recently marketed by the present applicants makes use of a two-part device in which the pressure drop on opening the can causes relative movement between the two parts, which movement causes tearing of a partition to allow the gas to exit the device via a plug assembly providing an accurately restricted orifice.

It will be appreciated that devices of this nature, to be commercially acceptable, must be produced in very high volumes at low cost and have a very low rate of failure or malfunction. These requirements pose severe problems of production engineering design, and the improvements of the present invention are directed towards mitigating such problems.

According to the present invention there is provided a device for inclusion in a pressurised fluid container for releasing a gas into the fluid in response to depressurisation of the fluid caused by opening of the container, the device comprising first and second body members each in the form of an open ended cylinder defined by a circumferential side wall and an end wall, the first and second body members being nestable together to define a closed cylindrical chamber, and one-way motion means provided on one of said body members adapted to engage the other of said body members in such manner as to permit sliding compressive movement while preventing sliding movement apart of the body members, the body members being provided with fluid control means which, in response to a predetermined decrease in pressure external to the device, defines a conduit through which fluid may exit said chamber through one or more openings of predetermined size.

Preferably, said fluid control means is constituted by a free edge of the side wall of one body member engaging over a channel in a surface of the other member.

Preferably, the free edge is deflectable at the seal with the other body member to allow gas to pass through the channel when the predetermined decrease in pressure takes place.

Said free edge is preferably formed to be a sliding sealing fit with the other member when the body members are not fully closed together.

Preferably, prior to the predetermined decrease in pressure, the free edge of the side wall of one body member forms a sealing fit with the other member.

Preferably, there are a plurality of channels disposed circumferentially around the other member.

Preferably, when said fluid control means is activated the free edge of one body member forms a sealing fit with the surface of the other member between the channels.

The one-way motion means may suitably comprise a column extending axially from the end wall of the one body member, the column carrying at its free end means frictionally engaging the side wall of the other body member. Said frictional engagement means are suitably in the form of a washer cooperating with a tapered surface of said side wall. The washer is suitably cruciform.

An embodiment of the present invention will now be described, by way of example, with reference to the drawings, in which:

Fig. 1 is a cross-sectional side view of a device in accordance with the invention in a storage and transit condition; Fig. 2 is an end view of the device as in Fig. 1; Fig. 3 is a cross-sectional side view of the device in the condition it assumes in a beverage can; Fig. 4 is an end view of the device as in Fig.5; and Fig. 5 is a cross-section of the two body parts of the device of Fig. 1 prior to assembly; Fig. 6 is a cross-section of the two body parts of Fig. 5 when sealably engaged; Fig. 7 is a diagrammatic detail view of the fluid control means of the device, circled and marked "7" in Fig. 3; Fig. 8 is a diagrammatic detail view of a first embodiment of the fluid control means of Fig. 7 on opening of the beverage can; Fig 9 is a detail view of a second embodiment of the fluid control means of the device; Fig 10 is a detail view of a third embodiment of the fluid control means of the device; and Fig 11 is a cross section of the inner body portion of the device.

The device comprises two body parts 10 and 12 and a retention washer 30.

One body part 10 is an outer body part having a cylindrical wall portion 16 and an end wall portion 18. The other body part 12 is an inner body part having a cylindrical wall portion 20 and an end wall portion 22. The inner and outer body parts 10 and 12 fit together telescopically to define a cylindrical chamber 24.

As shown in Fig. 5 the inner body part 12 has a cylindrical outer surface 20a of the cylindrical wall 20 with a diameter dl. The outer body part 10 has cylindrical inner surface 16a of the cylindrical wall 16 with a diameter of d2. d2 being slightly greater than dl. The lower edge 50 of the outer body part 10 has an inturned lip 52 which in the free state has a diameter d3 which is less than dl. The inner body part 12 has its top edge 54 chamfered to assist in fitting the two body parts 10 and 12 together as shown in Fig. 6. Fig. 6 shows that when the two body parts 10 and 12 are mated the lip 52 is deformed against the surface 20a to provide a seal.

The outer body part 10 further comprises a central column 26, in this example of cruciform section, projecting from the end wall 18 and terminating in a cylindrical stud 28. A retention washer 30 is an interference fit on the stud 28. The retention washer 30 comprises a central circular portion 30a from which extend four equispaced legs 30b, the outer ends of which bear on the inner surface of the cylindrical wall 20 of the inner body part 12. The retention washer 30 can be a stainless steel washer, or a plastic moulding.

The outer body 10 also comprises a number, in this embodiment twelve but this can be reduced to six, of integral leg portions 32. Each leg portion 32 is attached at one end to the periphery of the end wall portion 16, and has its other end received in an annular groove 34 of the opposite end wall portion 22. In the transit condition as shown in Fig. 1, the leg portions 32 lie axially of the device, forming in essence a cylindrical shell around it.

The end wall portion 22 of the inner body part 12 has a further annular groove 36 inwardly of the annular groove 34. As seen in Fig. 7, the groove 36 of the inner body part 12, has four very fine channels 56 spaced 90° apart circumferentially.

Three embodiments of the seal arrangement between the two body members 10, 12 are shown in Figs 7, 8, 9 and 10. The operation of the seal arrangement allowing the gas inside the chamber 24 to exit through the channels 56 is slightly different in each embodiment.

In the first embodiment of the seal arrangement shown in Fig 7 and 8, the channels 56 are provided in the groove 36 of the end wall portion 22 of the inner body part 12. The channels 56 extend from a bottom portion 60 of the cylindrical outer surface 20a of the inner body member 12 inside the groove 36, along the base 62 of the groove 36 and on the inner side of the projecting wall 64 which defines the groove 36. The lip 52 seals the two body portions 10, 12 as the lip 52 is sealed against the wall 20a above the channel 56. A gap 58 is provided between the cylindrical inner surface 16a of the outer body member 10 and the cylindrical outer surface 20a of the inner body member 12.

In the second embodiment of the seal arrangement shown in Fig 9 the channel 56 is only disposed on the inner side of the projecting wall 64 which defines the groove 36. The top portion 66 of the projecting wall 64 is angled towards the groove 36 and this top portion 66 provides a seal against the cylindrical outer surface 16b of the outer body member 10. The lip 52 of the cylindrical wall 16 seals against the cylindrical outer surface 20a of the inner body member 12. A slight gap 58 is provided above the lip 52 between the cylindrical inner and outer surfaces 16a and 20a of the outer and inner body members 10, 12.

In the third embodiment of the seal arrangement, the base 62 of the groove 36 has a flared portion 68 at the base of the cylindrical outer wall 20a of the inner body member 12. This flared portion 68 is due to moulding requirements and causes the seal with the lip 52 to be stronger. In this embodiment there is a point contact 76 between the inner side 74 of the projecting wall 64 which defines the groove 36 and the cylindrical outer surface 16b of the outer body member 10 in which the channels 56 are disposed.

If the flared portion 68 is removed the depth 70 of the groove 36 can be reduced. The height 72 of the inner body member (see Fig 11) and therefore the height of the outer body member can be made to suit the depth 70 of the groove 36.

In use, the device is assembled to the condition shown in Fig. 1 in a nitrogen atmosphere so that it contains nitrogen at atmospheric pressure. The lip 52 of the lower edge 50 of the outer body part 10 is formed to make a sliding seal against the outer surface of the cylindrical wall portion 18 of the inner body part 12, as seen in Fig. 6. The device can be stored and transported in this condition.

The device is inserted axially into a standard drinks can and is preferably pressed down in the can to seat against the bottom of the can and telescope to an intermediate, partially closed position (not shown) . The can is then filled with beverage, closed, and pasteurised in the normal way. During pasteurisation, the pressure in the can rises considerably and this closes the outer body part 10 down upon the inner body part 12 until the condition shown in Fig. 3 is attained. As shown in Fig. 3, this movement also causes the legs 32 to bow outwardly to grip the wall of the can (the lower part of the can being shown in broken lines in Fig. 5) to retain the device in position.

The operation of the three embodiments of the seal arrangement will now be described. When the device is fully collapsed, all three embodiments of the lip 52 form a seal against the cylindrical outer wall 20a of the inner body member 12, the seal is maintained by the fact that the pressure in the can external to the device is greater than the internal pressure in the chamber 24 of the device.

When the can is opened, the pressure in the beverage external to the device, drops rapidly to atmospheric, resulting in a substantial over-pressure in the chamber 24. There is a slight clearance 58 between the adjacent surfaces 20a and 16a of the two body parts 10 and 12 which allows the internal pressure to act behind the lip 52.

In the first embodiment of the seal arrangement (Figs 7 and 8) this over-pressure causes the lip 52 to deflect, such that the contact between the lip 52 and the surface 20a is only at the lowest point of the lip 52 which is situated over the channels 56. allowing gas to enter the channels 36 (see Fig. 8) . The lip 52 rolls such as to form a seal at the distal end 52a of the lip 52 such that gas exists only through the channels 56.

In the second embodiment of the seal arrangement (Fig 9) the lip 52 deflects and allows the gas to pass into a cavity 74 which is defined by the groove 36 and the cylindrical wall 16 of the outer body member 10 which seals with both sides of the groove 36. The gas can only exit from the cavity 74 through the channels 56.

The operation of the third embodiment of the seal arrangement is similar to that of the second embodiment, however there is only a point contact between the cylindrical outer wall 16a of the outer body member 10 and the projecting wall 64 in which the channels 56 are defined.

The gas exiting from the channels 36 in jets causes initiation of seed bubbles within the beverage as is well known per se.

The foregoing embodiment has a number of advantages in comparison with prior art devices. In particular, there are only three components and these are of a form which allows rapid assembly in a highly automated fashion. The two body members 10, 12 are suitably injection moulded from plastics material, while the retention washer may be stamped from metal or moulded from a relatively rigid plastic material. The washer 30 and central column 26 can be replaced with other means of keeping the two body members 10, 12 compressed together when the pressure external to the device has been reduced.

It would be possible in principle to engage the free end of the inner body member with a formation on the end wall the outer body member, to provide a seal which opens when the can is opened, but the arrangement described above is much more convenient to implement. Other modifications may be made to the foregoing within the scope of the invention.

Claims

1. A device for inclusion in a pressurised fluid container for releasing a gas into the fluid in response to depressurisation of the fluid caused by opening of the container, the device comprising first and second body members (10, 12) each in the form of an open ended cylinder defined by a circumferential side wall (16, 20) and an end wall (18, 22), the first and second body members (10, 22) being nestable together to define a closed cylindrical chamber (24) , and one-way motion means (26) provided on one of said body members (10) adapted to engage the other of said body members (30) in such manner as to permit sliding compressive movement while preventing sliding movement apart of the body members (10, 12), the body members (10, 12) being provided with fluid control (52) means which, in response to a predetermined decrease in pressure external to the device, defines a conduit through which fluid may exit said chamber (24) through one or more openings of predetermined size (56) .

2 A device as claimed in Claim 1, wherein said fluid control means (52) is constituted by a free edge of the side wall (16) of one body member (10) engaging over a channel (56) in a surface of the other member (12) .

3 A device as claimed Claim 1 or Claim 2, wherein the free edge (52) is deflectable at the seal with the other body member (12) to allow gas to pass through the channel (56) when the predetermined decrease in pressure takes place. 4 A device as claimed in any one of the preceding Claims wherein the free edge (52) is formed to be a sliding sealing fit with the said other member (12) when the body members (10, 12) are not fully closed together.

5 A device as claimed in any one of the preceding Claims, wherein prior to the predetermined decrease in pressure, the free edge (52) of the side (16) wall of one body member (10) forms a sealing fit the other member (12).

6 A device as claimed in any one of the preceding Claims, wherein there are a plurality of channels (56) disposed circumferentially around the other member (12) .

7 A device as claimed in any one of the preceding Claims, wherein when said fluid control means (52) is activated the free edge of one body member (10) forms a sealing fit with the surface of the other member (12) between the channels (56) .

8 A device as claimed in any one of the preceding Claims, wherein the one-way motion means suitably comprises a column (26) extending axially from the end wall (18) of one body member (10) , the column (26) carrying at its free end means (30) frictionally engaging the side wall (20) of the other body member (12) .

9 A device as claimed in any one of the preceding Claims, wherein said frictional engagement means (30) are suitably in the form of a washer cooperating with a tapered surface of said side wall (20) .

A device as claimed in any one of the preceding Claims, wherein the washer (30) is suitably cruciform.