GB2268727A - A beverage frothing device - Google Patents

Abstract

A device for production of a foamy head on a beverage packaged within a sealed, non-resealable container comprises a fluid chamber formed by two generally hollow telescopically slidable members 1, 2 which have means, eg a projection on one member and an apertured spider or washer on the other member, for securing the two members in a telescopically compressed position. Means, eg aperture 8, (111, Figure 7), are also provided for fluid communication between the fluid chamber and the exterior of the device in response to a predetermined reduction in the pressure external to the device on opening the container. Preferably an armed cage arrangement 3 is disposed around the two members, the arms curving away from the members and exerting a force against the insides of the beverage container when the two members are telescopically compressed thereby holding the device in place in the container. The projection on member 1 may have a ratchet function 11-13, the aperture 8 may be closed initially by an O-ring (6, Figure 1), the projection member may be pierced by the washer (115, Figure 7) to provide the fluid communication and a spherical metering element (313, Figure 10) may be provided. Alternatively a fluid communication orifice may be provided between a leading edge of one member and an adjacent part of the second member (Figures 13-15). During beverage packaging the closed container including the device is pasteurised to produce internal pressure and cause compression of the device. <IMAGE>

Description

"Packaainq for Beverages" This invention relates to a device for generation of a foaming dispersion of bubbles within a liquid packaged within sealed, non-resealable cans or other containers.

It is especially although not exclusively suited to use with canned alcoholic beverages such as beer, ale, porter, stout or lager but may also be used with non-alcoholic soft drinks.

A device and method for the production of a foamy dispersion of bubbles or "head" is desirable in beverages such as beer, ale, porter, stout or lager since these beverages often lack such a head when sold in canned form. Head generation is assisted by the release of gas dissolved in the beverage when it is depressurised whether by being drawn from a keg as with draught beverage, or by opening of a can or bottle. In draught beverages this is enhanced by the pressurisation of kegs with carbon dioxide (CO2), nitrogen (N2) or other inert gases, establishing a higher concentration of dissolved gases in draught beverage than in canned beverage. Thus draught beverages usually release more bubbles during depressurisation and have more dense, longer lasting heads than canned beverages.

Prior art has addressed these problems by various methods.

Disclosure has been made of various moulded inserts which are gas filled and discharge their gas through an orifice in the insert upon depressurisation of the can.

The energy released from the insert upon depressurisation is highly temperature sensitive causing inconsistent head production at varying temperatures. At room temperature this may result in excessive foaming and loss of beverage.

Alternative approaches to the problem include cans modified to comprise one chamber for beverage and one for gas that mix when the can is opened. This sophisticated design of can leads to high costs and could prove unviable.

Various intermediate systems exist where gas chambers are incorporated in can lids or bases. In addition chemical methods of inducing a head have been disclosed but it is unclear to what extent these affect the taste of the beverage.

According to a first aspect of the present invention there is provided a beverage frothing device for a beverage container, the device having a fluid chamber formed by two generally hollow telescopic slidable members sealably slidable one within the other, wherein means are provided for securing the two members in a telescopically compressed position and means are also provided for causing fluid communication between said fluid chamber and the exterior of the device in response to a predetermined reduction in the pressure external to the device.

The securing means may be in the form of a projection member projecting from one of the generally hollow telescopically slidable members and an engagement member attached to the other generally hollow telescopically slidable member for engaging the projection member.

The device may have means for holding the device inside a beverage container, the holding means exerting a force against the inside of the beverage container as the device is telescopically compressed.

The two telescopic members may compress to a first position and in this first position the holding means may hold the device inside the beverage container and the two telescopic members may further compress to a second position thereby increasing the fluid pressure in the fluid chamber to a desired level.

Preferably, the holding means is in the form of a cage attached to outer ends of the two generally hollow telescopically slidable members, the cage having a plurality of arms which curve away from the two members as the two members are telescopically compressed.

A spacer component may be disposed within the fluid chamber in order to regulate the internal volume of the fluid chamber and thereby the pressure of the fluid chamber.

Preferably, the device contains a non-oxidising gas such as nitrogen or carbon dioxide.

Preferably, the two members are cylinders each having one open end, the open ends being placed together and having closely fitting sealing means.

The fluid communication means may be in the form of a piercing means which pierces an aperture in the fluid chamber. The fluid communication means may further include a metering aperture for regulating the fluid emitted from the fluid chamber.

The piercing means may be disposed on the engagement member of the securing means and may pierce a wall of the projection member, the projection member being hollow and the interior of the projection member communicating with the exterior of the device via the metering aperture.

The engagement member may be in the form of a securing washer which grips the projection member for securing the two generally hollow telescopically slidable members when telescopically compressed, and the securing means may be provided with points suitable for piercing the wall of the projection member only when there is a predetermined reduction in the pressure external to the device.

Preferably, the securing washer is generally dish-shaped and has an uneven inner rim formed with piercing points, the dish shape of the washer providing a one way securing means for the projection member, and said points acting as the piercing means on reduction of a predetermined amount of external pressure.

The projection member may be tapered and may have a lateral step or shoulder to limit telescopic compression of two members.

Alternatively, the fluid communication means may be in the form of a wall of one of the generally hollow telescopically slidable members which acts against a closing means for an aperture in the other telescopically slidable members.

Preferably, the projection member has at least one portion heaving a cross-sectional area larger than an opening in the engagement member.

The securing means may be arranged to engage in each of three predetermined positions and the projection member has three corresponding portions of relatively large cross-sectional area in relation to an opening in the engagement member.

The securing means may be a three detent pin which interengages with an opening in the engagement member which member is in the form of a spider across the open end of one of the generally hollow telescopically slidable members, the detent pin being forced through the opening when the members are compressed.

One of the telescopic members may have aperture initially closed by an O-ring seal located in a recess over the aperture, and a wall of the other member replaces the O-ring as the closing means for the aperture as the members are compressed, said wall not covering the aperture when the detent closest to the fixed end of the projection member is above the opening in the spider.

The two detents furthest from the fixed end of the projection member are hooked so as to prevent their retraction through the opening in the spider and the third detent can retract through the opening when the pressure external to the device reduces suddenly.

As a further alternative, a first of the members may be telescopically slidably received within the second member, a restricted orifice being provided between a leading end of the second member and an adjacent part of the first member through which the fluid within the fluid chamber may pass in response to a predetermined reduction in the pressure external to the device.

The second member may have a generally cylindrical internal surface whilst the first member has an outwardly extending flange portion against which the leading end part of the second member may engage.

The flange or the leading end portion may be provided with at least one slot to provide said restricted opening.

The flange may be provided with an annular channel portion in which the leading end of the second member is received.

The restricted openings may be provided between the leading end portion and the channel at spaced circumferential positions According to a second aspect of the present invention there may be provided a method of producing a packaged beverage, comprising providing an open topped container, placing in the container a device in accordance with first aspect of the present invention, filing the container with beverage, closing the top of the container with a closure member and subjecting the closed container to pasteurisation thereby producing internal pressure in the container which compresses the device.

The method may also involve placing the device in the container until one end of the device abuts the bottom of the container and mechanical pressure may be applied to the other end of the device to bring engagement means into engagement with the container.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig 1 is a longitudinal section of a first embodiment of the beverage frothing device in accordance with the present invention in an uncompressed position; Fig 2 is a longitudinal section of the device of Fig 1 in a partially compressed position; Fig 3 is a longitudinal section of the device of Fig 1 in a position of maximum compression; Fig 4 is a longitudinal section of the device of Fig 1 in a released position; Fig 5 is a plan of the spider of the device of Fig 1 not attached to the device; Fig 6 is a perspective view of the cage of the device of Fig 1 not attached to the device; Fig 7 is a longitudinal section of a second embodiment of the beverage frothing device in accordance with the present invention;; Fig 8a and 8b are a plan view and side view respectively of the washer of the device of Fig 7; Fig 9 is a longitudinal section of a third embodiment of the beverage frothing device in accordance with the present invention; Fig 10 is a longitudinal section of one half of a fourth embodiment of the beverage frothing device in accordance with the present invention; Fig 11 is a plan of the washer of the fourth embodiment of the device of Fig 10; Fig 12 is a detail of the interlocking arm arrangement of the fourth embodiment of-the device of Fig 10; Fig 13 is a longitudinal section of a fifth embodiment of a device in accordance with the invention in an uncompressed condition; Fig 14 is a similar section to that of Fig 13 but showing the device in a compressed condition and in position within a container; and Fig 15 is a detail of a cross-section of the device of Fig 13.

Referring to the drawings, the first embodiment of the device is in accordance with the present invention as illustrated in Figs 1 to 6. The beverage frothing device comprises two mutually nestable cylinders 1, 2 each with one open end 15 and one closed end 16. The first cylinder 1 fits over the second cylinder 2, the second cylinder 2 having a sealing lip 9 at its open end 15 which acts against the internal surface 17 of the first cylinder 1. The device is filled with nitrogen at atmospheric pressure. The device also has a surrounding cylindrical cage 3 (Fig 6) which is retained in position around the cylinders 1, 2 by extensions 18 to the closed ends 16 of the two cylinders 1, 2. This cage 3 is formed of a flexible plastic material.

The first cylinder 1 has a centrally positioned three-detent pin 5 attached to or moulded as part of the first cylinder 1 and projecting from the interior surface of the closed end 16 of the first cylinder 1.

The second cylinder 2 has a spider 4 (Fig 5) which is attached across the open end 15 of the second cylinder 2. This spider 4 has a central opening 10 which acts as a pawl with respect to the three step ratchet function of the detent pin 5. The second cylinder 2 also has small metering apertures 8 positioned in the side wall 20 of the second cylinder 2 near the closed end 16 of the second cylinder 2 and the apertures 8 are disposed at the base of a groove 19 on the exterior of the side wall 20. An O-ring formed of a rubber material 6 may sit in the small groove 19, thus covering the apertures 8 and sealing them. There is also a parking groove 7 for the bring 6 below the apertures 8.

Fig 1 shows the device in its initial position prior to being immersed in a beverage in a beverage container which container is preferably in the form of a can.

The device is dropped into the can in the canning line.

Thereafter during sterilisation of the can, pressurised carbon dioxide or nitrogen is used to purge the can.

This pressure results in the two cylinders 1, 2 being telescopically compressed together by the rise in external pressure around the device such that the first detent 11 is pushed through the central opening 10 of the spider 4 (position of Fig 2). As the two cylinders 1, 2 are compressed together the arms of the cage 3 around the two cylinders 1, 2 curve outward from the two cylinders 1, 2. The cage 3 curves out from the two cylinders 1, 2 sufficiently to contact and exert a force on the internal walls of the can (not shown).

This force holds the device in place in the base of the can during filling of the can. It is not crucial that the device is substantially vertically placed within the can; it may be at a slight angle to the longitudinal axis of the can without affecting the operation of the device. The two cylinders 1, 2 in their nested uncontracted form are too long for the device to lie horizontally in the base of the can and thereby be rendered inoperable. The device may be dropped into the can with either of the two cylinders uppermost.

When the pressure is reduced again, at the end of the sterilisation, the device remains in a contracted position as the first detent 11 latches on the opposite side of the spider 4 and the hooked top 21 of the first detent 11 prevents the return of the first detent 11 through the central opening 10 of the spider 4.

The can is then filled with the beverage, in this case beer, and closed. During pasteurisation of the can, the temperature rises and the pressure inside the can increases. The two cylinders 1, 2 are squeezed further together such that the second 12 and third 13 detents are forced through the opening 10 in the spider 4 (position of Fig 3) and the two cylinders 1, 2 are telescopically compressed to the maximum extent. As a consequence of the further compression of the two cylinders 1, 2, the open end 15 of the first cylinder 1 pushes the O-ring 6 from its position covering the apertures 8 down into the parking groove 7. The apertures 8 remain closed as they are covered the wall 14 of the first cylinder 1. The cage 3 is forced into an even more curved form which results in the arms of the cage 3 being further forced against the internal wall of the can.

When the can is opened, the sudden release of the pressure external to the device results in the third detent 13 being forced back through the opening 10 in the spider 4 (position of Fig 4). This is possible as this third detent 13 is not hooked unlike the first 11 and second 12 detents which are prevented from retraction through the opening 10. As the third detent 13 retracts through the central opening 10 in the spider 4, the two cylinders 1, 2 decompress a relative amount due to the internal pressure of the device. The apertures 8 are uncovered as the wall 14 of the first cylinder rises as the two cylinders 1, 2 are decompressed and the gas escapes through these apertures 8 as seed bubbles which rise through the beer to form a creamy head when the beer is poured from the can.

A second embodiment of the device in accordance with the present invention is given below and illustrated in Figs 7 and 8.

This beverage frothing device comprises two telescopically nestable moulded containers 101, 102.

The first container 101 has a closed end 106 and two concentric cylindrical walls 103, 104. The first container 101 also has moulded arm extensions 105 spaced circumferentially around the closed end 106 of the first container 101. The arm extensions 105 have hinged areas 107 or are flexible thereabouts.

The second container 102 also has a closed end 108 with a tapered projection 110 projecting centrally toward the first container 101 from the inside surface of the closed end 108. The tapered projection 110 has a central hollow recess 109. The recess 109 is closed to the outside of the device by a controlled orifice member 111. The second container 102 has two concentric cylindrical walls 112, 113. The outer one of these walls 112 nests outside the first cylinder outer wall 103 and has a sealing means 114 which seals these outer walls 103 and 112 but allows relative movement of the walls 103 and 112. The second container inner wall 113 is located between the inner wall 104 and the outer wall 103 of the first container 101.

A washer 115 is held inside the open end 116 of the inner cylinder wall 104 of the first container 101 by holding means 117. The washer 115 has a central opening 118 in the form of a broken circle 119.

Positioned at the breaks 119 in the circle are internally pointing piercing means 120. The washer 115 is dish-shaped with its centre 121 projecting towards the closed end 106 of the first container 101 and towards the end of the tapered projection 110.

The closed end 108 of the second container 102 has restraints 123 at the periphery of this end 108 in which the arm extensions 105 of the first container 101 are held.

In use the two telescopically nestable containers 101, 102 which are formed out of a moulded plastics material are placed nestably together in a nitrogen atmosphere so that the central tapered projection 110 of the second container 102 is placed inside the central opening 118 of the washer 115 held by the first container 101. The dish shape and internally pointing piercing means 120 of the washer 115 prevent the tapered projection 110 from retracting through the washer 115 and thereby prevents the two containers 101, 102 from separating.

The device is dropped into a beverage can in a nitrogen atmosphere and the increase in pressure external to the device as the beverage can is sterilised causes the inner cavity 124 between two containers 101, 102 to contract and the arm extensions 105 of the first container 101 to curve outwards or bend at the hinge areas 107 and exert a force against the inside of the beverage can.

As the beverage can is filled with beverage, sealed and pasteurised the pressure inside the beverage can rises and the two containers 101 and 102 are further compressed together such that the portion of the tapered projection 110 of the second container 102 which portion encloses the hollow recess 109 is positioned inside the washer 115. The part of the tapered projection 110 enclosing the recess 109 has a thin wall 122 separating the recess 109 and the washer 115.

The pressure gradually drops inside the beverage can as the beverage cools after pasteurisation. The two containers do not move apart as they are held by the tapered projection 110 interacting with the rim of central opening 118 of the washer 115 which rim has internally pointing piercing means 120.

However, the sudden decrease in pressure inside the can external to the device when the can is opened causes the tapered projection 110 to slip a small distance out of the washer 115, and in doing so, the piercing means 120 of the broken circle 119 of the washer 115 pierce the thin walls 122 of the tapered projection 110 enclosing the recess 109.

The gas in the inner cavity 124 defined by the two containers 101, 102 is pressurised as the inner cavity 124 has contacted reducing the volume in the inner cavity 124 inside the containers 101, 102 and causing the pressure of the gas within the inner cavity 124 to rise. The pressurised gas thus escapes through the pierced holes in the thin wall 122 of the tapered projection 110. The gas then escapes to the exterior through the controlled metering orifice member 111 at the entrance to the hollow recess 109, the controlled orifice member 111 ensures that the bubbles of the escaping gas are of an exact size. The gas bubbles rise through the beverage can seeding other bubbles and cause a creamy head on the beverage when it is poured from the can.

A third embodiment of the device in accordance with the present invention is given below and illustrated in Fig 9.

This embodiment is similar to the second embodiment of the device and the beverage frothing device comprises two telescopically nestable moulded containers in the form of two cylinders 201, 202, each having a generally closed end 203 and an opened end 204. The second cylinder 202 is telescopically slidable within the first cylinder 201. The edge 205 of the open end 204 of the second cylinder 202 has a flared lip 206 which is radially inwardly compressed when the two cylinders 201, 202 are nestably interconnected. The interiors of the two cylinders 201, 202 define a variable volume of internal chamber 207 for storing a gas such as nitrogen.

The first cylinder 201 has a projection member 208 of generally solid cylindrical form which has a laterally projecting step or shoulder 209 on its outer surface.

A portion 210 of the projection member 208 proximate to the closed end 203 of the first cylinder 201, is in the form of a reduced strength wall 211 which defines a hollow recess 212 in the closed end 203. The recess 212 is substantially closed by a spherical elastomeric metering element 213. At least one groove 214 is provided in the surface 215 which communicates the exterior and interior of the recess 212 via the metering element 213.

An inner cylindrical wall 216 projects inwardly from the closed end 203 of the second cylinder 202. At the opposite end 217 of the inner cylindrical wall 216 to the closed end 203 of the second cylinder 202 is disposed a washer 217 which has a central hole 218 with a plurality of inward points 219 inclined in a downward direction towards the closed end 203 of the second cylinder 202.

A separate spacer insert 220 of a generally open ended cylindrical form is positionable in the area between the inner cylindrical wall 216 and the external wall of the second cylinder 202. The separate spacer insert 220 has a flanged end 221 which extends inwardly.

In use, the device of this embodiment acts in a manner similar to the second embodiment. However, when the device is inserted into the beverage container the device is mechanically compressed until the shoulder or step 209 of the projection member 208 engages the washer 217 and thereby offers increased resistance to further telescopic compression of the two cylinders 201 and 202.

The shoulder or step 209 is forced to engage the washer 217 when the beverage is sealed in the container and pasteurised due to the increase in pressure external to the device which the pasteurisation involves. When the can is opened and the pressure external to the device is sharply reduced, the washer 217 will rupture the reduced strength wall 211 as before. The pressurised gas in the internal chamber 207 is released into the recess 212 through the rupture in the reduced strength wall 211. This gas escapes from the recess 212 through the groove 214 disposed around the metering element 213. The escaping gas seeds further small bubbles in the beverage and causes a creamy head on the beverage when it is poured from the beverage container.

The separate insert 220 can be varied in size such that the volume of the internal chamber 207 can be varied and correspondingly define the pressure of the fluid in the device.

A fourth embodiment of the device in accordance with the present invention is given below and a detail of the fourth embodiment is illustrated in Fig 10.

This embodiment of the device is closely similar to the second and third embodiments of the present invention.

The fourth embodiment has two nestable moulded containers in the form of two mutually telescopic components 301 and 302 similar to the two cylinders 201 and 202 of the third embodiment.

As an alternative to the use of the flared lip 206 of the edge 205 of the open end 204 of the second cylinder 202 in the third embodiment (Fig 9) for direct mutual sealing of the two cylinders 201 and 202, in the fourth embodiment 300 (Fig 10) the mutually telescopic components 301 and 302 equivalent to the cylinders 201 and 202 are dimensioned for mutual telescoping with a small radial gap between them. Mutual sealing of the components 301 and 302 is accomplished by radially outwardly extending a flanged end 321 of the separate spacer insert 320, forming the outer circumference of this extension 322 as biaxially flared skirts 323 (upwardly directed) and 324 (downwardly directed).The flared skirts 323, 324 slidingly contacting the internal surface of the wall 325 of the outer one 301 of the two telescopic components to form a doubleacting seal therewith, and chamfering the rim 326 of the inner one 302 of the telescopic components to provide an airtight seal with the underside of the adjacent one 324 of the two sealing skirts. Fig 10 shows for illustrative purposes a gap between the chamfered rim 326 and the downwardly directed flared skirt 324. In practice the rim 326 and the skirt 324 are airtightly sealed.

A central projection member 308 is of a frusto-conical form and has a laterally projecting step or shoulder 309 on its outer surface. The projection member 308 contains a hollow recess 312 surrounded by a thin wall 311 of the projection member 308. The recess 312 is closed at the closed end 303 of the first telescopic component 301 from which the projection member 308 projects, by means of a spherical metering element 313.

The metering element 313 is surrounded by four circumferentially located groves 314 which communicate the exterior of the telescopic component 301 and the recess 312 within the projection member 308.

An inner cylindrical wall 316 projects inwardly from the closed end 303 of the inner one of the telescopic components 302. A washer 317 is disposed across the free end of the inner cylindrical wall 316. The washer 317 has a central hole 318 with a plurality of inward points 319. The plurality of inward points 319 shown in Fig 11 are arranged in the form of two oppositely arranged two sided acute angled points 400 and two inward points 319 between the two-sided acute angled points 400 in the form of flared rectangular projections 402 with a two sided angled shape removed from each rectangle to form a double angled point. The washer 317 is formed of a metal material and has leaves 330 which are bent around the outer wall of the free end of the inner cylindrical wall 316.

The separate spacer insert 320, which forms the sealing means of the two telescopic components 301 and 302, is of generally cylindrical form with one open end 312 and is positionable with the open end 312 in the area 322 between the inner cylindrical wall 216 and the external wall of the inner telescopic component 302. The second generally closed end of the separate insert 320 sits above the inner cylindrical wall 316 of the inner one of the telescopic components 302 and has a central opening 329 which is disposed above the central opening 318 of the washer 317.

The projection member 308 projects through the central opening 329 of the separate insert 320 and through the central opening 318 of the washer 317 such that the thin wall 311 of the projection member 308 enclosing the hollow recess 312 is adjacent to the plurality of inward points 319 of the washer 317.

The inner of the telescopic components 302 has twelve circumferentially disposed arm members 305 which are joined by hinges 341 to the periphery of the closed end 303 of the inner telescopic component 302. The arm members 305 are also mutually joined by joining members in order to ensure that the arm members 305 remain attached to each other in the event of the failure and dislocation of the hinged joint 341 with the inner telescopic component 302.

The free ends of the arm members 305 which are not attached at the hinge 341 to the inner of the telescopic components 302 are locatable in a lipped overhang 342 projecting from the closed end 303 of the outer of the telescopic components 301 as shown in Fig 12. The free ends of the arm members have laterally projecting ends shaped so as to be mutually interlockable 352 to prevent individual arm members 305 from escaping from the lipped overhang 342. The mutually interlocking form 352 is in the form of angled projections 350 and recesses 351 in each of the laterally projecting ends.

The circumference of the closed end 303 of the inner of the telescopic components 302 has a small longitudinally projecting wall 345 which has regularly circumferentially disposed recesses.

In use the device of this fourth embodiment acts in a similar manner to the second and third embodiments.

The device is compressed until the shoulder 309 of the projection member 308 engages the washer 317 and offers increased resistance to further compression of the two telescopic components 301 and 302.

The shoulder 309 is forced to engage the washer 317 when the beverage is sealed in the container and pasteurised. When the can is opened the pressure external to the device is sharply reduced and, as before, the washer 317 will rupture the thin wall 311 of the projection member 308. The pressurised gas in the internal chamber 322 defined by the telescopic components 301 and 302 is released into the hollow recess 312 through the rupture in the thin wall 311.

The gas escapes from the recess 312 through the four groves 314 disposed around the spherical metering element 313.

The escaping gas seeds further small bubbles in the beverage and causes a creamy head to be formed on the beverage when it is poured from the container.

A fifth embodiment of the device in accordance with the present invention is given below and illustrated in Fig 13, 14 and 15.

The fifth embodiment is illustrated at 500 and is intended for inclusion in a pressurised fluid container, 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 is substantially or suddenly reduced by opening the container and thereby exposing the interior of the container to atmospheric pressure as with the previous embodiments.

The device is shown in position in such a container C in Fig 14. The device 500 comprises a first member 501 having a first generally hollow tubular portion 502 having a cylindrical external surface 503 and a frustoconical internal surface 504 so that the thickness increases in a direction extending away from a leading end 505 of the first portion 502 towards a trailing end 506 thereof at which the member 501 is formed integrally with a transversely extending end wall 507.

Extending away from the end wall 507 is a tubular boss 508 having an external cylindrical surface 509 and an internal frusto-conical surface 510 which decreases slightly in diameter in the direction away from the leading end 505 towards the trailing end 506.

The member 501 is provided with a separately formed insert or spacer member 520 of generally tubular form having a cylindrical internal surface 521 and a stepped frusto-conical external surface 522. The insert member 520 is disposed in the space between the surfaces 504, 509 mentioned hereinbefore. The spacer member is dimensioned to provide an unoccupied volume 523 of a desired size. By providing an insert member 520 of a desired size, the size of the unoccupied volume 523 may be varied to achieve a desired pressurise within the insert in use.

The insert member 520 is provided, at its upper end, with an inwardly directed flange 524 which rests on the leading end surface 525 of the boss 508 to limit inward movement of the spacer member.

The spacer member 520 is provided with a lip 526 which is initially flared outwardly and which extends outwardly and towards the trailing end 506 of the member 502.

The device 500 also comprises a second member 529 comprising a second tubular part 530 having an internal surface 531 of cylindrical configuration and an external surface 532 of frusto-conical configuration which is of reducing diameter in a direction away from the trailing end 533 towards a leading edge 534 of the second member 529.

At its trailing end 533 the tubular part 530 is formed integrally with an end wall 535 and a spigot 536 extends from the wall 535 centrally thereof.

The spigot is of frusto-conical configuration decreasing in diameter towards the leading end 534 of the member 529 and carries at its leading end a washer 537.

The washer 537 has a central opening provided with inwardly directed teeth which bite into a reduced diameter part 538 of the spigot 536, which the washer abuts a shoulder 539 of the spigot 536. The outer periphery of the washer is generally circular but provided with outwardly projecting teeth to dig into the internal surface 510 of the hollow boss 508. The hollow boss 508 is provided with a flared end 540 to facilitate entry of the washer 537.

The lip 526 of the member 502 undergoes inward compression when the portion 502 is inserted into the portion 530 thereby affording an efficient seal between the portions 502 and 530. The inner surface 531 of the portion 530 is dimensioned to provide a good sliding fit with the lip 526 and as a result the interiors of the first and second portions 502, 530 define a variable volume chamber 541 for storing said substance.

Formed integrally with the end wall 507 of the member 501 are a plurality, for example 4 or 6, of flexible arm members 550. Each arm member 550 is provided with a first hinge part 551 where it is connected to the wall 507. At its opposite end each arm 550 is provided with a part 552 which is of enlarged circumferential extent compared with the remainder of the arm and is adapted to be receive within a slot 553 formed in the wall part 535 as the members 502 and 530 are moved together. The enlarged circumferential extent of the part 552 ensures that adjacent parts 552 adjacent arms about and this prevents circumferential displacement of the arms relative to the slot 553.

The part 552 is connected to the remainder of the arm by a second hinge part 554 and a third hinge part 555 is disposed between the first and second hinge parts and closer to the first hinge part so that a first portion 556 of the arm extends between the first and third hinge parts whilst a second portion 557 of the arm, which is of greater extent that the first portion 556, extends between the second and third hinge parts.

The third hinge part is of relatively great longitudinal extent and comprises a reduced crosssection portion of the arm.

The leading end 534 of the tubular portion 530 is formed with tip 558 having a counter-bore of frustoconical configuration and the wall 507 is provided with a circular channel or groove 559 which is adapted to receive the tip 558. The channel 559 is provided with a plurality, for example 6, grooves 559, as best shown in Fig 15.

The grooves 559a are of semi-circular cross-section channel shape but may be of other desired crosssection.

The tip 558 of the leading end part 534 in the present example abuts the base of the groove 559 but if desired may be spaced therefrom but closely adjacent thereto.

A rim 560 is provided beneath the wall 507 and has at least one opening 561 therein.

In use, the members 501 and 529 are provided initially as separate parts and the interiors of the members are then purged of air or the like in the conventional manner, for example under the action of pressurised nitrogen gas jet. Immediately after the purging whilst the interior of the members are still occupied by the purging nitrogen gas they are brought together and the flared lip 526, of the first portion 502, is inserted into the second portion 532 as a sliding fit against the surface 531. With a seal thus maintained the portions 502 and 530 are then slid telescopically closer together through a predetermined extent.The engagement of the internal and external teeth of the washer 537 with the spigot 536 and the boss 508 ensures that the portions 502 and 530 are retained in the predetermined disposition event though the gas within the chamber 541 has been compressed above atmospheric pressure.

As the members are initially telescoped together the parts 552 of the arms are engaged in the slot 553 and limited outward bulging of the arms takes place. At an appropriate stage after initial bringing together of the members 502 and 503 and sealing of the chamber 541 the unit is engaged within a container with which it is intended to be used. In the present example the container is a beverage can such as a beer can, but the container may be any other suitable container such as a bottle made of glass or plastics material with the unit and the arms being appropriately dimensioned to suit the configuration of the container and the desired volume of substance to be dispensed.

When the assembled unit has been inserted into an empty fluid container and telescopically compressed to a desired predetermined extent so as to achieve an initial compression of the nitrogen gas, the interior of the container into which the unit has been inserted is purged of air or the like, for example under the action of a jet of compressed nitrogen gas, and the fluid to be stored in the container is then admitted to the container and the container sealed in the conventional manner.The container thus containing the insert 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, the result of which is that any residual nitrogen purging as in the container or gases that have dissolved in the fluid, for example beverage, become heated and thereby increase the pressure within the container. The effect of this pressure increase is to force the members 502 and 530 to telescopically compress further until the tip 558 is received within the groove 559.The members 502 and 503 are maintained in that compressed state under the action of the tines of the washer 537 digging into the wall of the hollow boss 508 and the reduced diameter part 538 of the spigot 536 when the container returns to room temperature and is stored thereafter in a refrigerated storage.

The above described final compression causes the arms to occupy the position shown in Fig 14 where the first arm portion 556 extends transversely away from the unit in a generally radially outwardly and downward direction relative to the container C whilst the third hinge portion 555 rests on the usual shoulder 562 of a conventional beverage can. The second arm portion 550 has a first part 563 which engages the internal cylindrical wall 564 of the container C and a second part 565 which extends generally transversely to the unit and is inclined downwardly and outwardly. As a result the unit is securely held in the container adjacent the bottom end thereof.

The rim 560 engages a base part 566 of the container C and the aperture 561 permits escape of any beverage or other contents of the container from within the rim.

The rim 560 ensures that the unit is correctly positioned within the container.

When the container is opened so as to expose the initially pressurised material of the container to atmospheric pressure of the gas within the chamber 541 is sufficient to force it past the lip 526 and along the interface 567 between the surfaces 533 and 503 and then through the grooves 559a and thus into the beverage in the container C. The release of the compressed nitrogen into the fluid, such as a beverage, has the effect of causing the formation of a head or "frothing" of the beverage.

If desired, substances other than pressurised nitrogen gas may be stored in the unit 500 is desired.

The device of all the above embodiments can be inserted axially into a beverage container such as a can. The known prior art devices require orientation to enter any beverage container which has a neck portion of smaller diameter than the body of the container. The present device, prior to compression, can be inserted in a container with a neck portion of smaller size than the body of the container. The inserted shape of the device is independent of the can size due to the fact that the arm members curve outward from the device only on compression of the two members of the device after insertion in a beverage container.

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 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.

Modifications and variations of the above described embodiment can be adopted without departing from the scope of the invention.

Claims (27)

Claims

1. A beverage frothing device for a beverage container, the device having a fluid chamber formed by two generally hollow telescopic members sealably slidable one within the other, wherein means are provided for securing the two members in a telescopically compressed position and means are also provided for causing fluid communication between said fluid chamber and the exterior of the device in response to a predetermined reduction in the pressure external to the device.

2. A beverage frothing device as claimed in Claim 1 wherein the securing means is in the form of a projection member projecting from one of the generally hollow telescopically slidable members and an engagement member attached to the other generally hollow telescopically slidable member for engaging the projection member.

3. A beverage frothing device as claimed in Claim 1 or Claim 2, wherein the device has means for holding the device inside a beverage container, the holding means exerting a force against the inside of the beverage container as the device is telescopically compressed.

4. A beverage frothing device as claimed in Claim 3, wherein the two telescopic members are compressed to a first position and in this first position the holding means holds the device inside the beverage container and wherein the two telescopic members are further compressed to a second position thereby increasing the fluid pressure in the fluid chamber to a desired level.

5. A beverage frothing device as claimed in Claim 3 or Claim 4, wherein the holding means is in the form of a cage attached to outer ends of the two generally hollow telescopically slidable members, the cage having a plurality of arms which curve away from the two members as the two members are telescopically compressed.

6. A beverage frothing device as claimed in any one of the preceding claims, wherein a spacer component is disposed within the fluid chamber in order to regulate the internal volume and thereby the pressure of the fluid chamber.

7. A beverage frothing device as claimed in any one of the preceding claims, wherein the device contains a non-oxidising gas.

8. A beverage frothing device as claimed in any one of the preceding claims, wherein the two members are cylinders each having one open end, the open ends being placed together and having closely fitting sealing means.

9. A beverage frothing device as claimed in any one of Claims 1 to 8, wherein the fluid communication means is in the form of a piercing means which pierces an aperture in the fluid chamber.

10. A beverage frothing device as claimed in Claim 9, in which the fluid communication means further includes a metering aperture for regulating the fluid emitted from the fluid chamber.

11. A beverage frothing device as claimed in Claim 10 when dependent on Claim 2, wherein the piercing means is disposed on the engagement member of the securing means and pierces a wall of the projection member, the projection member being hollow and the interior of the projection member communicating with the exterior of the device via the metering aperture.

12. A beverage frothing device as claimed in any one of Claims 9 to 11, wherein the engagement member is in the form of a securing washer which grips the projection member for securing the two generally hollow telescopically slidable members when telescopically compressed, and the securing washer is provided with points suitable for piercing the wall of the projection member only when there is a predetermined reduction in the pressure external to the device.

13. A beverage frothing device as claimed in Claim 12, wherein the securing washer is generally dish shaped and has an uneven inner rim provided with said piercing points, the dish shape of the washer providing a one way securing means for the projection member, and said points acting as the piercing means on reduction of a predetermined amount of external pressure.

14. A beverage frothing device as claimed in any one of Claims 2 to 13, wherein the projection member is tapered and has a lateral step or shoulder to limit telescopic compression of two members.

15. A beverage frothing device as claimed in any one of Claims 1 to 8, wherein the fluid communication means is in the form of a wall of one of the generally hollow telescopically slidable members which acts against a closing means for an aperture in the other telescopically slidable member.

16. A beverage frothing device as claimed in Claim 2, wherein the projection member has at least one portion having a cross-sectional area larger than an opening in the engagement member.

17. A beverage frothing device as claimed in Claim 16, wherein the securing means is arranged to engage in each of three predetermined positions and the projection member has three corresponding portions of relatively large cross-sectional area in relation to the opening in the engagement member.

18. A beverage frothing device as claimed in Claim 17 wherein the projection member is a three detent pin which interengages with an opening in the engagement member which member is in the form of a spider across the open end of one of the generally hollow telescopically slidable members, the detent pin being forced through the opening when the members are compressed.

19. A beverage frothing device as claimed in Claim 18, wherein one of the telescopic members has an aperture initially closed by an O-ring seal in a recess over the aperture, and a wall of the other member replaces the O-ring as the closing means for the aperture as the members are compressed, said wall not covering the aperture when the detent closest to the fixed end of the projection member is above the opening of the spider.

20. A beverage frothing device as claimed in Claim 18 or 19, wherein the two detents furthest from the fixed end of the projection member are hooked so as to prevent their retraction through the opening in the spider and the third detent is shaped to permit retraction through the opening when the pressure external to the device reduces suddenly.

21. A beverage frothing device as claimed in any one of Claims 1 to 8 wherein a first of the members is telescopically slidably received within the second member, a restricted orifice being provided between a leading end of the second member and an adjacent part of the first member through which the fluid within the fluid chamber may pass in response to a predetermined reduction in the pressure external to the device.

22. A beverage frothing device as claimed in Claim 21, wherein the second member has a generally cylindrical internal surface whilst the first member has an outwardly extending flange portion against which the leading end part of the second member may engage.

23. A beverage frothing device as claimed in Claim 21 or 22, wherein the flange or the leading end portion is provided with at least one slot to provide said restricted orifice.

24. A beverage frothing device, as claimed in Claim 22 or 23, wherein the flange is provided with an annular channel portion in which the leading end of the second portion is received.

25. A beverage frothing device as claimed in any one of Claims 21 to 24, wherein the restricted orifices are provided between the leading end of the second member and the adjacent part of the first member at spaced circumferential positions.

26. A method of producing a packaged beverage, comprising providing an open-topped container, placing in the container a device in accordance with Claim 1, filling the container with beverage, closing the top of the container with a closure member and subjecting the closed container to pasteurisation thereby producing internal pressure in the container which compresses the device.

27. A method of producing a packaged beverage in accordance with Claim 26 wherein the device is placed in the container until one end of the device abuts the bottom of the container and applying mechanical pressure to the other end of the device to bring engagement means into engagement with the container.