WO1995026308A1

WO1995026308A1 - Improved head producing device for beverages

Info

Publication number: WO1995026308A1
Application number: PCT/GB1995/000671
Authority: WO
Inventors: Jonathan William Brown; Philip Dyson Theaker
Original assignee: Scottish & Newcastle Plc
Priority date: 1994-03-29
Filing date: 1995-03-27
Publication date: 1995-10-05
Also published as: AU1956895A; GB9406194D0

Abstract

A device for use in a can which is to be filled with beverage and sealed and pressurised in known manner, adapted for location within the can so as to remain submerged within the beverage until the can is opened and the latter is dispensed, and which as a result of the pressurisation of the can itself becomes pressurised as the contents of the can pressurise after the can is sealed. The device is constructed at least in part as a hollow annular chamber (10) having a small orifice (36) in the wall thereof and is adapted to be retained within the can at a height such that at least the orifice remains submerged in the beverage when the can has been filled, whether the can is upright or not. One form of the device is a ring, the outside diameter of which is less than the diameter of the open end of the can through which the beverage is poured, to facilitate its entry. The orifice is located in a section of the chamber wall which faces radially inwardly, and its position is such that when the can is pressurised the volume of beverage which will enter the chamber is insufficient to reach the level of the hole. In a preferred arrangement the chamber is divided internally by a baffle (74) which divides the chamber into inner and outer annular compartments, internal communication between the inner and outer annular compartments only being provided at an elevated position therewithin. In another arrangement the device comprises a hollow cylindrical capsule the upper face of which is dished axially inwardly so as to form a significant depression or bowl, and the gas jetting orifice is formed in the dished surface.

Description

Title : Improved head producing device for beverages

Field of invention

This invention concerns devices for producing a foamed head on a beverage such as beer or lager when the latter is dispensed from a can in which the beverage has been stored under pressure.

Background to the invention

Various devices have been proposed during the past few years for insertion in pressurised beverage cans during the filling process which as a result of the pressurisation of the can become themselves pressurised with a quantity of gas which when the can is finally broached and the beverage dispensed, causes a jet of gas to shoot into the beverage and form a foamed head on the beverage.

On grounds of cost and reliability, the simpler devices which do not involve moving parts are preferred and it is one object of the present invention to provide an alternative design of gas jetting device for use in a pressurised beverage can as aforesaid, the construction of which is very simple and does not impede the filling of a can using conventional can filling apparatus.

It is another object of the present invention to provide a gas jetting device for use as aforesaid particularly in cans containing highly carbonated beverages such as lagers.

In this connection it should be explained that the devices designed for use with relatively low carbonated beers and beverages seem to have too much effect when used with higher carbonated beverages and excessive effervescence and frothing has been found to occur. The second stated objective has this problem in mind.

Summary of the invention

According to one aspect of the present invention in a can which after filling with beverage is pressurised in known manner there is provided a device for location within the can so as to remain submerged within the beverage until the can is opened and the latter is dispensed, and which as a result of the pressurisation of the can itself becomes pressurised as the contents of the can pressurise after the can is sealed, wherein the device is constructed at least in part as a hollow annular chamber having a small orifice in the wall thereof, and is adapted to be retained within the can at a height such that it remains submerged below the beverage when the can has been filled and whether the can is upright or not .

The device may be in the form of a ring the outside diameter, of which is preferably less than the diameter of the open end of the can through which the can is filled. In the case of two piece spun aluminium cans such as are conventionally used for such beverages as beer, lager and the like, this open end is of reduced diameter relative to the body of the can, so that a shoulder is formed in the can wall.

The ring may be held in position within the can by means of resiliently deformable fingers extending radially and axially therefrom so as to be capable of being collapsed inwardly to permit the ring to be inserted through the neck of the can but spring out immediately thereafter to engage the can below the shoulder and thereby retain the ring in position, below the shoulder of the can.

Alternatively the hollow annular ring may be located within an outer deformable ring of resiliently deformable material typically plastics material or the like and joined thereto by two or more resiliently deformable fingers or spokes so that by squeezing the outer ring, it can be passed through the neck of the can and thereafter be located below the shoulder defining the can neck with the axis of the annular ring substantially co-axial with the axis of the can.

The orifice is preferably located in a section of the wall of the chamber which faces radially inwardly.

Preferably the position of the hole is such that when the can is pressurised the volume of beverage which has entered the chamber ring is insufficient to reach the level of the hole or is only just capable of reaching the hole so that the gas trapped above the intruding beverage is available to jet through the orifice when the can is depressurised on broaching.

Since the pressure within the chamber has to balance the pressure within the can after the can has been sealed, as a rough guide the position of the hole may be such that the volume of the chamber below the hole in proportion to the total volume of the chamber should be commensurate with the depth of beverage in the can as to the height of the can.

According to a particularly preferred aspect of the invention, a hollow annular chamber device as aforesaid may be constructed most simply from two annular channel members one having a radial width just greater than the other, but the same mean radius, so as to form a lid for the other when fitted thereto, so that the two halves can be fitted together to form the closed member chamber.

The two annular channel members may be formed from a plastics material and may be moulded and fused together as by heat seaming or by means of an adhesive, or screw threaded, or fitted by means of a snap fit connection.

Whatever method of joining the two members together is employed, it is important that the joint shall be fluid tight and in particular gas tight at least at the maximum pressures expected within a can (ie a maximum of 6 or 7 bar) , so that gas trapped within the ring can only exit through the orifice in the wall of the ring and will not leak through the joint when the can is depressurised on broaching.

The means for retaining the device at a given height within a can may be attached to one or other of the two members forming the chamber, or to both of them.

The internal diameter of the annular ring is selected so as to represent a clearance fit around a conventional level detector which conventionally enters a can from above during the filling process . The device is therefore capable of being fitted near the top of the can since it does not impede the insertion of the level detector into the can.

According to a particularly preferred feature of the invention, the interior of the chamber may be divided internally by a baffle which extends from the base of the chamber (ie the lower part of the chamber when the can is standing upright) and which divides the chamber into inner and outer annular compartments for internal communication between the inner and outer annular compartments only being provided at an elevated position therewith.

A device constructed thus will still become pressurised internally by the intrusion of beverage through the small orifice (which it is assumed is in the radially inner wall of the housing and thus communicates with the inner annular compartment as defined by the baffle) , but because of the compressibility of the gas within the chamber, the intruding beverage will tend to displace all of the gas from the inner compartment chamber through the high level communication between the two compartments, and if the volume of the compartments is appropriate, the radially inner compartment will become filled with beverage up to the level of the communicating means after which beverage will flow through or over the baffle into the radially outer compartment until the pressure of the trapped gas equals the pressure within the can.

It is conventional on canning lines to invert a can so as to check for leaks which are most likely to show up when the internal pressure of the can is elevated as during pasteurisation and it will be seen that when the can is inverted, the high level communication between the inner and outer radial compartments within the chamber will now be located at the bottom of the device. During pasteurisation therefore the gas charge is completely trapped at what is now the top of the chamber and any additional beverage which is driven into the capsule through the orifice as the temperature and pressure is raised during pasteurisation will leave the chamber again via the orifice as the temperature drops during the cooling phase of the pasteurisation cycle so that there will be no net gain or loss of beverage. However the gas charge will have been protected against leakage during the pasteurisation stage so that when the can is inverted to stand on its base once again, the full gas charge which was trapped in the chamber originally will still be available and will now communicate via the high level communication through or over the top of the baffle with the inner radial compartment within the chamber.

By making the width of the radially inner compartment (measured in a radial sense) much smaller than that of the outer comparcment, the bulk of the liquid will occupy the radially outer region of the ring and will be separated from the jetting orifice by the baffle. If the can is stood upright and then broached, beverage within the radially inner compartment of the ring below the level of the orifice will remain in the ring and the only beverage which has to precede the gas jetting is any beverage in the radially inner compartment above the level of the jetting orifice. By making the radially inner compartment as small as possible, so the amount of beverage to be jetted ahead of the gas can be made very small and the device can be made relatively efficient.

It is an advantage of a device fitted with an internal baffle that the orifice can be located substantially midway of the height of the annular chamber which means that the interchange of beverage or gas into and out of the chamber will be substantially the same whether the can is standing on its base or its head.

The volume of beverage to be jetted ahead of the gas can be further reduced by providing two baffle walls on either side of the orifice which extend to the cylindrical baffle so as to define a narrow channel between the orifice and the top of the baffle which defines the two compartments so that the only beverage which needs to be jetted through the orifice to allow gas to escape is that contained in the narrow channel communicating with the orifice and defined by the main baffle and the two baffle walls.

In the alternative, a generally vertical drilling may be provided in the wall of the chamber to communicate with the orifice at its lower end and with another orifice (communicating with the chamber) at its upper end.

Although the term drilling has been used, it is to be understood that the passage does not need to be formed by a drilling operation but may be formed by a moulding operation using appropriate tooling so that the passage is formed during the moulding of the chamber wall.

According to another aspect of the present invention, a gas jetting device for fitting within a pressurised can containing beverage and which is designed to be immersed below the level of the beverage in the can and to jet gas when the can is broached comprises a hollow cylindrical capsule adapted to be secured at a particular height within the can spaced from the internal can wall, with the axis of the cylindrical capsule co-axial with the axis of the can, and wherein the upper face of the capsule is dished axially inwardly so as to form a significant depression or bowl, and the gas jetting orifice is formed in the dished surface. The upper peripheral edge of the capsule may be cut away so as to define a weir over which beverage can pass to fill up the dish at least to the level of the weir and provide beverage within the dished surface of the capsule into which gas from the orifice can jet when the can is broached.

The depth of the dishing in the upper face of the capsule may be such that the dished surface merges with the flat base at the lower end of the capsule and if desired the central region of the dished surface may be removed so as to form a central circular aperture with the upper dished surface bonded to the lower flat surface of the capsule around the circumference of the opening.

The device may be retained within a can by means of a bounding circle of resilient plastics (or other resilient material) secured thereto by means of resiliently deformable radial fingers. Alternatively resiliently deformable radial fingers can extend from the capsule so as to engage the interior of the can and the diameter of the capsule is selected so that with the fingers flattened against the side of the capsule, the latter can be pushed through the reduced neck of the can into position below the can shoulder whereupon the resilient fingers are designed to spring out and engage the inside of the can below the shoulder and hold the capsule in position.

The cut-away upper edge of the capsule defining the weir is preferably located at a circularly remote position relative to the position of the orifice. Typically the orifice and the weir are diametrically opposed.

Such a device is of particular use in connection with highly carbonated beverages, particularly highly carbonated lagers and beers, in which only a very small volume of jetted gas will produce a considerable head of froth as compared with that which would be obtained for the same quantity of gas jetting with a lower carbonated beverage.

Provided the outer diameter of the capsule is sufficiently spaced inwardly from the inside wall of the can, there will be a sufficient annular space outside the device to permit beverage to flow into and out of the can, even if the dished surface of the second embodiment is continuous, and there is no central aperture.

The capsule may be formed from two parts namely an upper cylindrical body having a closed, concavely dished upper end and an open lower end and a circular base having an upstanding lip within which the cylindrical lower open end of the upper dished housing can be fitted. The two parts may be bonded, welded, adhesively secured, screw threadedly engaged or snap fitted the one to the other.

In use, beverage is driven into the interior of the capsule through the small orifice as the can is pressurised until the gas trapped in the capsule attains the same pressure as the internal pressure of the can and at that stage no further beverage enters the capsule. When the can is broached, the trapped gas issues out of the small orifice into the puddle of beverage in the dished surface and a frothy head is produced in the restricted volume of beverage.

As the can contents are poured out, so the froth passes out of the can with the liquid and forms the desired head on the poured beverage.

The advantage of an internal baffle as previously described in relation to the first embodiment can be obtained in a similar manner by providing an upstanding cylindrical wall at an appropriate position on the circular base so as to cooperate ^'with the dished end of the upper part to form two chamber compartments and provide an internal annular weir over which ingressing beverage has to flow before it can gain access to the radially outer compartment, where it will remain and cannot interfere with the subsequent ejection of gas from the headspace trapped above the beer.

The annular ring and the dished cylindrical housing may be formed from plastics material, typically injection moulded plastics material.

The area of cross section of the gas jetting orifice will typically be very small and if it cannot be formed during the moulding process, a laser drilling step may be incorporated into the manufacturing process to form the hole at a convenient point in time, typically after the device has been assembled.

In the case of alcoholic beverages such as beers and lagers, it is important that oxygen is not present in the can and to this end the capsules may be constructed in an inert atmosphere such as nitrogen. The small hole may be formed in the wall of the capsule only after the device has been inserted into its can and just before the can is filled with beverage. This may be achieved by inserting a laser probe into the can to the desired position and causing a laser beam to impinge on the capsule surface thereby to form a small hole therethrough.

Alternatively the device may be formed with the orifice and may be purged of oxygen and filled with Nitrogen gas after being fitted in a can, and the can is then filled with water to at least cover the device until just before filling in the manner described in copending UK Patent Application No. 9309015.7.

The baffle may extend from top to bottom of the chamber to define inner and outer annular compartments and may be provided with one or more small apertures therein at a high level relative to the base, through which beverage and gas can pass between one chamber and the other, or may simply extend from the base towards the roof of the chamber with a small gap between the top of the baffle and the roof, through which beverage and gas can pass.

A particularly simple form of construction of two compartment chamber device comprises a first cylindrical shell having a closed end and an open end, and having around its exterior an annular ledge the outermost edge of which is upturned to form an annular retaining wall and a second cylindrical shell also having a closed and an open end, whose external diameter equals the internal diameter of the said annular retaining wall so that the second shell can be fitted over the open end of the said first shell and fitted within the said annular retaining wall, the axial length of the first shell between the ledge and its open end being less than the axial length of the second shell so ■ as to leave a gap internally between the open end of the first shell and the closed end of the second shell.

A small aperture is formed in the wall of the second shell to provide the orifice. The two shells may be secured in any convenient manner as by an adhesive or welding or a screw thread or a snap fit, or the like.

The wall of the first shell extending upwardly from the ledge comprises a baffle which divides the interior into a first compartment (between that section of the first shell wall and the outer second shell wall) and a second compartment which comprises an interior of the first shell.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an assembled annular gas jetting device;

Figure 2 is a perspective view of the annular closure which is fitted to the underside of the annular body shown in Figure 1;

Figure 3 shows how two component parts can be snap fitted together;

Figure 4 is a cross-section through the device shown in Figure 1 showing how the upper part fits into the base;

Figure 5 is a perspective view of an assembled alternative design of gas jetting device;

Figure 6 is a perspective view of the underside closure of the device shown in Figure 5;

Figure 7 is a cross-section of the device shown in Figure 5 showing how the two parts fit together;

Figures 8, 9 and 10 are similar views of an alternative arrangement in which the dished surface of the body and the circular base are apertured so as to form an annular device;

Figure 11 is a view similar to that of Figure 2 of an alternative base which includes an upstanding weir;

Figure 12 is similar to Figure 4 and shows in cross-section how the weir cooperates with the annular body to form an alternative annular gas jetting device to that shown in Figure 1;

Figure 13 is a perspective view of an assembled alternative design of gas jetting device based on that shown in Figure 5;

Figure 14 is a perspective view of the base section of the assembled device of Figure 13 ;

Figure 15 is a cross-section through the device shown in Figure 13 showing how the weir shown upstanding from the base of Figure 14 cooperates with the dished upper part of the device shown in Figure 13 to divide the interior;

Figure 16 is a perspective view of a two-part device constructed as a further embodiment of the invention;

Figure 17 is a perspective view of the base having upstanding cylindrical weir which forms part of the arrangement shown in Figure 16;

Figure 18 is a cross-section through the assembly of the two parts making up the gas jetting device shown in Figure 16;

Figure 19 is a hollow cylindrical lid, the lower face of which as shown in Figure 19 is open; Figure 20 is a cylindrical base member which cooperates with the hollow lid of Figure 19, the cylindrical base of which is closed and the upper end of which is open; and

Figure 21 is a cross-section through an assembly of the two parts shown in Figures 19 and 20 forming a gas jetting device.

Detailed description of drawings

Figure 1 illustrates an annular gas jetting device comprising a hollow annular body 10 and an annular tray 12 which is secured thereto so as to form a gas tight seal.

The base 12 is shown in Figure 2 and a snap fit seal is shown in Figure 3 as illustrating one manner in which the outer wall of the hollow annular body 10 can be secured to an upstanding wall 14 of the base 12.

A similar snap fit connection may be provided (although not shown) between the internal upstanding wall 16 of the base 12 and the corresponding internal wall 18 of the annular body 10.

Within the same internal radial wall 18 is an aperture 20 through which liquid can ingress and gas in use.

Figure 4 is a cross-section through the arrangement shown in Figure 1.

The device can be fitted within a can such as a two-piece drinks can by means of resilient tabs such as 22, 24, 26 and 28. Although four such tabs are shown, it will be understood that two or three may be sufficient. The tabs are resiliently deformable but sufficiently stiff to form a friction fit with the interior of the can without damaging the surface thereof so that if the ring is pushed down into the can it will stay put wherever it is left in the can.

An alternative arrangement for locating the ring device within the can comprises an outer resiliently deformable plastics ring secured to the outer radial wall 30 of the body 10 by means of resiliently deformable radial fingers (not shown) such that the outer ring (not shown) is a tight fit within a cylindrical drinks can so as to retain the ring device within the can.

The components parts shown in Figures 1 and 2 may be formed from plastics materials and it will be seen that by using a snap fit seal as shown in Figure 3 , the device can be radially assembled either by hand or by an automated process.

The design of the two component parts shown in Figures 1 and 2 is such as to readily admit the construction thereof by injection moulding or the like.

An alternative form of device is shown in Figures 5 to 7. This comprises a cylindrical shell 32 the lower end of which is open and the upper end of which is dished to form a generally concave wall 34 within which is located a gas jetting aperture 36. A cylindrical tray shown in Figure 6 comprises the base 38 the outer wall of which is shown at 40 in Figure 5.

The outer wall of the cylindrical section 32 of the upper part of the two-part device is adapted to be a close fit within the outer wall 40 of the base 38. The two may be secured by a snap fit or by an adhesive or by welding. Tabs, one of which is denoted by reference numeral 42 extend from the upper regions of the cylindrical shell 32 for the same purpose as the tabs 22 etc in Figure 1.

Alternatively the device can be fitted within a drinks can by means of an outer bounding ring of plastics material secured to the main body 32 by means of resiliently deformable radial spokes also of plastics material.

As with the arrangement shown in Figures 1 to 4, the two parts forming the alternative arrangement shown in Figure 5, can also be moulded from plastics material.

Figure 7 is a cross-section through the two assembled parts and illustrates the cross-sectional shape of the fluid retaining region of the capsule. This is part cylindrical and part annular.

As shown in Figure 5, the upstanding wall of the dished shell 32 may be cut away as denoted by reference numeral 44. Typically the cut away region 44 is diametrically opposite the gas jetting aperture 36. The cut away 44 permits beer or other beverage to access over the bowl during filling to allow ball and cage of standard filler to control fill height. The cut away 44 also assists in forming the aperture 36 as for example by laser drilling.

The device is located near the top of the can but is totally submerged when the can is filled and when the pressurised can is broached, gas trapped within the interior 46 of the device jets out through the hole 36 causing frothing of the beverage trapped within the dished section of the device. Frothing of beverage outside the device is restricted to whatever effect is transmitted through the cut away region 44 and this tends to reduce the frothing of the remainder of the beverage within the can.

The device is thus of considerable advantage when used with highly carbonated beverages such that even a small amount of gas jetting will result in excessive frothing.

The device is thus suitable for use with lighter beers and lagers and the like which tend to over-froth when conventional gas jetting devices such as previously proposed are used to produce a head on the beverage when the can is opened.

Figures 8 to 10 illustrate an alternative arrangement similar to that shown in Figures 5 to 7 but in which the circular base 48 is centrally apertured at 50 and the dished upper surface of the body 52 (corresponding to the body 32 of Figure 5) is likewise apertured and formed with a radial wall which forms a close sealing fit with the circular opening 50 in the base 48.

The wall of the body 52 may be cut away as shown at 56 in the same way as the wall of the body 32 is cut away at 44 in Figure 5.

The internal dished wall of the body 52 is formed with a gas jetting aperture 58 similar to the aperture 36 in Figure 5 and resilient tabs one of which is shown at 60 may be provided for securing the device within a drinks can.

The outer wall of the body 52, as in the case of the Figure 5 embodiment, it sealingly secured within the upstanding cylindrical wall 62 of the base 48 and may be a snap fit therein such as shown in Figure 3 or secured by adhesive or welding.

Figures 11 and 12 show an alternative design of device similar to that shown in Figures 1 to 4 but in which the annular base is constructed in a different way.

As shown in Figure 11, the annular base generally designated 64 includes an upstanding cylindrical wall 66 upstanding from the annular base 68, equally radially spaced from the internal wall 70 of the base. The arrangement is more clearly seen in Figure 12 which is a cross-section through the assembled device. The upper part of the assembly is similar to the body 10 shown in Figure 1 and similar reference numerals have been used to denote similar parts.

The inner wall 70 and outer wall 72 of the base shown in Figure 11 are snap fitted adhesively secured or welded or otherwise sealingly joined to the inner and outer walls 18 and 30 of the body member 10 and the cylindrical wall 66 extends upwardly into the annular cavity from the base 68 so as to form a weir which is nearer the inner wall than the outer wall 30. The upper edge of the wall 66 is spaced from the wall of the body 10 by a small gap so as to permit fluid to flow from one side to the other of the weir.

Tabs such as 22 and 28 may be provided for securing the device within a drinks can or alternatively a bounding ring secured to the -body 30 or to the base 12 by means of resiliently deformable radial spokes may be provided for securing the device in a can at a desired height.

As with the Figure 1 and 2 devices, the two parts making up the assembly shown in Figure 12, are also equally readily moulded from plastics material as by injection moulding.

Figures 13 to 15 illustrate a modification of the device shown in Figures 5 to 7 in which the circular base 38 includes an upstanding dished wall 74 (see Figures 14 and 15) which serves as a weir within the annular cavity formed between the body and base 32 and 40. The upstanding cylindrical weir is shown cut away and in cross-section in Figure 1 . It is in fact a continuous ring of material wider at the base than at the top and formed integrally with the base 38.

In order to reduce the bulk of material required, the wall 74 may be formed by moulding the material forming the base 38 as shown in Figure 14A. As far as the fluids within the annular cavity are concerned, the effect is the same but the amount of plastics or other material from which the devices are formed can be significantly reduced.

Tabs such as 42 may be provided for securing the device within a drinks can or alternatively a bounding ring and resiliently deformable radial spokes may be provided around either the base 38 or the body 32 for securing the device in a drinks can.

The walls 74 constitutes an annular weir which divides the annular cavity into two parts which communicate over the top of the weir. A small hole 36 is formed in the inside wall of the dish base 32 for jetting gas when the can is broached.

Figures 16 to 18 illustrate an alternative gas jetting device comprising a cylindrical lid 76 secured to a cylindrical base 78 which as shown in Figure 17 includes a cylindrical upstanding wall 80 which constitutes a weir within the cylindrical interior of the device when the lid and base are joined together. This is best seen in Figure 18.

The outer cylindrical wall 82 of the lid may be sealingly engaged with the upstanding cylindrical wall 84 of the base by means of a snap fit such as shown in Figure 3 or by means of adhesive or by welding.

The two parts 76, 78 may be formed by plastics injection moulding or may be formed from metal.

The outer wall 76 includes a gas jetting aperture 86 and tabs such as 42 are provided around the device for securing the latter in a drinks can. An alternative arrangement for securing the device in a can may comprise a bounding ring of plastics material and resiliently deformable radial spoken joining the ring to the outside of the lid 76 or the base 78.

Figures 19 to 21 illustrate a modification of the arrangement shown in Figures 16 to 18. Here the lid 76 is the same as that shown in Figure 16 but the base is twice as deep and whilst being close to the bottom end as shown in Figure 20, is open at the upper end. The modified base is denoted by reference numeral 88.

Substantially half way down the base 88, is located an annular tray generally designated 90 comprising an annular base 92 and cylindrical upstanding wall 94. Wall 94 corresponds to wall 84 in Figure 17 and wall 76 of the lid is sealingly secured to wall 94 of Figure 20 in the same way as described in relation to Figures 16 to 18.

The lower end of the cylindrical housing 88 is closed as will be seen from the cross-section in Figure 21 by the closed end 96. The upper end is open and the axial length of the cylindrical member 88 is such that when the lower edge 98 of the lid 76 rests against the platform 92, there is a small gap 98 between the upper edge 100 of the member 88 and the inside of the closed end 102 of the lid 76.

As with the device shown in Figures 16 to 19, tabs 42 may be provided to secure the device at the desired position within a drinks can or a bounding ring attached to the assembly by means of resiliently deformable radial fingers or spokes may be provided instead.

The two parts 76 and 88 may be formed from plastics material by injection moulding.

In general all of the parts making up all of the devices shown in the drawings could be formed from metal either as shown or with minimal modification to assist in metal drawings, stamping and forming techniques to be used to form the different upstanding annular walls and divisions as required.

Since the devices are to be fitted in metal cans, there is an advantage in forming the gas jetting devices from metal to facilitate recycling.

In use, each of the devices shown in Figures 1 to 10 operates in a similar manner. Each constitutes an annular cavity which initially contains gas at atmospheric pressure typically Nitrogen, to avoid any oxygen contamination of the beverage. After filling a can with beverage and pressurisation as by Nitrogen dosing, beverage will be forced through the small hole such as 20 in Figure 1 into the annular cavity until the pressure of gas and beverage within the annular cavity equals the pressure within the can.

By locating the aperture 20 at an appropriate position relative to the overall height of the device, the aperture 20 will still communicate with the gas which will become trapped above the liquid which enters the annular cavity so that when the can is broached, the charge of gas trapped above the liquid and at a pressure of typically three atmospheres or more will be available to jet through the small hole into the beverage which on broaching the can will now be at atmospheric pressure. The jetting will produce a froth on the top of the beverage in known manner.

The device shown in Figures 5 and 8 tends to separate the beverage within the dished interior of the device from the rest of the beverage in the can and the jetting of gas through the small hole 36 will tend to reduce the extent of the frothing to what can be obtained by jetting gas into the beverage contained within that dished interior of the device. The frothing is essentially produced by causing dissolved Nitrogen in the beverage to be released in the form of tiny bubbles and clearly once the dissolved Nitrogen has been so released, further jetting of gas into the frothed beverage will not result in any increase in frothing. Any dissolved gas will tend to come out of solution in these conditions and where a beverage is highly carbonated as well as having Nitrogen dissolved therein, excessive frothing can result. By restricting the volume of beverage which can be frothed in this way to that contained in the well within the device and any beverage above that well, so the amount of frothing which would otherwise occur will be reduced and excessive frothing which might otherwise occur particularly in highly carbonated beverages, will be prevented.

The aperture 50 in the device shown in Figures 8 to 10 means that this device effects less separation between the beverage above and below the device than for example the device shown in Figure 5 but a reduction in frothing is still achievable. The advantage of the device shown in Figure 8 is that beverage entering the can can more readily pass down through the device into the lower regions of the can during filling than is the case with the device shown in Figure 5.

The devices shown in Figures 11 et seq operate in a similar manner but by virtue of the weir provided by the upstanding wall in each of the arrangements shown tends to separate the gas from the liquid which has entered the device during the priming phase and tends to restrict the quantity of liquid which is available to be jetted perhaps ahead of any gas so as to make the device more efficient since it is the gas rather than the jetting of beverage which produces the frothing effect.

Claims

1. A device for use in a can which is to be filled with beverage and sealed and pressurised in known manner, adapted for location within the can so as to remain submerged within the beverage until the can is opened and the latter is dispensed, and which as a result of the pressurisation of the can itself becomes pressurised as the contents of the can pressurise after the can is sealed, wherein the device is constructed at least in part as a hollow annular chamber having a small orifice in the wall thereof and is adapted to be retained within the can at a height such that at least the orifice remains submerged in the beverage when the can has been filled, whether the can is upright or not .

2. A device as claimed in claim 1, wherein the device is in the form of a ring and the outside diameter of the ring is less than the diameter of the open end of the can through which the beverage is poured.

3. A device as claimed in claim 1 or 2 for use with a can whose open end is necked, further comprising resiliently deformable fingers extending radially and axially therefrom so as to be capable of being collapsed inwardly to permit the device to be inserted through the neck of the can but which will spring outwardly immediately thereafter to engage the interior of the can below the shoulder defining the necked end thereof to thereby retain the ring in position, below the shoulder of the can.

4. A device as claimed in claim 1 or 2, wherein the hollow annular ring is located within an outer deformable ring of resiliently deformable material and is joined thereto by two or more resiliently deformable fingers or spokes so that by squeezing the outer ring, its overall diameter can be reduced to permit it to pass through the open end of the can and thereafter be located in the can co-axially therewith.

5. A device as claimed in any of claims 1 to 4, wherein the orifice is located in a section of the chamber wall which faces radially inwardly.

6. A device as claimed in any of claims 1 to 5, wherein the position of the orifice is such that when the can is pressurised the volume of beverage which will enter the chamber is insufficient to reach the level of the hole, so that the gaseous content of the device which becomes trapped above the intruding beverage is available to jet through the orifice when the can is depressurised on broaching.

7. A device as claimed in any of claims 1 to 6, wherein the hollow device ring is constructed from two annular channel members one having a marginally greater radial width than the other but the same mean radius, that the one can fit within the other, to form the annular chamber.

8. A device as claimed in claim 7, wherein the two members are formed from a plastics material and fused together as by heat seaming or secured by means of an adhesive, or screw threadedly engaged, or fitted by means of a snap fit connection, or welded together so as to form a gas tight join so that fluid can only enter and exit the chamber through the orifice in the wall thereof.

9. A device as claimed in claim 7 or 8, wherein the means for retaining the device within the can is attached to one or other of the two members which form the chamber.

10. A device as claimed in any of claims 1 to 9, wherein the internal diameter of the annular ring is selected so as to represent a clearance fit around a conventional level detector which conventionally enters a can from above during the filling process, thereby to permit the device to be fitted near the top of a can if desired since it thereby does not impede the insertion of the level detector into the can.

11. A device as claimed in any of claims 1 to 10, wherein the chamber is divided internally by a baffle which extends from the base of the chamber (ie the lower part of the chamber when the can is standing upright) and which divides the chamber into inner and outer annular compartments for internal communication between the inner and outer annular compartments only being provided at an elevated position there-within.

12. A device as claimed in claim 11, in which the small orifice is located in the radially inner wall of the chamber, and thereby communicates with the inner radial chamber (as defined by the cylindrical baffle) whereby in use intruding beverage will tend to displace the gas trapped in the inner radial compartment through the high level communication between the two compartments into the radially outer compartment.

13. A device as claimed in claim 12, wherein in use the radially inner compartment will become filled with beverage up to the level at which communication occurs between the two compartments after which beverage will flow through or over the baffle into the radially outer compartment, until the pressure of the trapped gas equals the pressure established within the can.

14. A device as claimed in claim 11 or 12 or 13 , in which the width of the radially inner chamber, measured in a radial sense is less than that of the outer chamber, so that the bulk of the liquid which enters the ring will enter the radially outer region of the ring and will thereby be separated from the jetting orifice by the baffle, so that if the can is broached when upright, beverage within the radially inner compartment of the ring, below the level of the orifice, will remain in the ring and only if beverage is above the level of the orifice will it be available to jet out through the orifice.

15. A device as claimed in any of claims 11 to 14, wherein the orifice is located substantially midway of the height of the annular chamber so that the interchange of beverage and/or gas into and out of the annular ring will be substantially the same whether the can is standing on its base or upside down and standing on its top.

16. A device as claimed in any of claims 11 to 15, wherein the volume of beverage to be jetted ahead of the gas can be further reduced by providing two baffle walls on either side of the orifice which extend to the cylindrical baffle, so as to define a narrow channel between the orifice and the top of the cylindrical baffle so that it is only beverage (if any) in the said channel which needs to be jetted through the orifice to allow gas contained in the device to be jetted.

17. A device as claimed in any of claims 11 to 15, wherein the wall of the capsule includes a generally vertical passage or drilling which communicates with the orifice at its lower end and via another orifice communicates with the upper end of the chamber at its upper end.

18. A gas jetting device for fitting within a pressurised can containing beverage and which is designed to be immersed below the level of the beverage in the can and to jet gas when the can is broached, comprising a hollow cylindrical capsule adapted to be secured at a particular height within the can, spaced from the internal can wall, with the axis of the cylindrical capsule coaxial with the axis of the can, and wherein the upper face of the capsule is dished axially inwardly so as to form a significant depression or bowl, and the gas jetting orifice is formed in the dished surface.

19. A device as claimed in claim 18, wherein an upper peripheral edge of the capsule is cut away so as to define a weir over which beverage can pass to fill up the dish at least to the level of the weir and ensure beverage occupies the bowl so that when the can is broached, gas trapped under pressure within the device will jet out through the orifice into the beverage in the bowl.

20. A device as claimed in claim 18 or 19, wherein the depth of the dishing in the upper face of the capsule is such that the dished surface merges with the flat base over a central region of the lower end of the capsule, and the central region of the dished surface is removed so as to form a central circular aperture with the upper dished surface bonded to the lower flat surface of the capsule around the circumference of the opening.

21. A device as claimed in claim 18, 19 or 20, which is adapted to be retained within a can by means of a bounding circle of resiliently deformable material secured thereto by means of resiliently deformable radial fingers.

22. A device as claimed in claim 18, 19, 20 or 21 wherein resiliently deformable radial fingers extend from the capsule to engage the interior of the can, the diameter of the capsule being selected so that with the fingers at least partially flattened against the side of the capsule, the latter can be pushed through the open end of the can into position within the can, whereupon the resilient fingers will spring out and engage the inside of the can and hold the capsule in position.

23. A device as claimed in claim 19, wherein the cut-away upper edge of the capsule defining the weir is located at a circularly remote position relative to the position of the orifice.

2 . A device as claimed in claim 23 , wherein the orifice and the weir are diametrically opposed.

25. A device as claimed in any of claims 18 to 24 when fitted in a can containing a relatively highly carbonated beverage from, which with very little gas jetted, a considerable head of froth is produced as compared with that which would be obtained for the same quantity of gas jetted into less carbonated beverage.

26. A device as claimed in any of claims 18 to 25, wherein the capsule is formed from two parts namely an upper cylindrical body having a closed, concavely dished upper end and an open lower end, and a circular base having an upstanding lip within which the lower edge of the open end of the upper dished housing can be fitted, and the two parts are bonded, welded, adhesively secured, screw threadedly engaged or snap fitted the one to the other to form a fluid tight joint, so that, in use, when fitted within a can containing beverage under pressure, beverage is driven into the interior of the capsule through the small orifice as the can pressurise until gas trapped in the capsule attains the same pressure as that of the interior of the can, whereafter no further beverage enters the capsule.

27. A device as claimed in claim 26, wherein there is provided a cylindrical wall upstanding from the circular base, so as to cooperate with the interior of the dished end of the upper part, to provide an annular weir internally of the device over which ingressing beverage has to flow into the radially outer region and where it will remain and therefore not interfere with the subsequent ejection of gas from the headspace in the device trapped above the beverage.

28. A device as claimed in any of the preceding claims, wherein the area of cross section of the gas jetting orifice is very small, and the orifice is either formed during a moulding process or by laser drilling after the device has been at least partly constructed and/or assembled.

29. A device as claimed in any of claims 1 to 28, wherein a baffle extends from the top to bottom of the chamber to define inner and outer annular compartments and is provided with at least one aperture at a high level relative to the base of the chamber through which liquid and gas can pass between the one compartment and the other.

30. A device for fitting within a can which is to be filled with beverage and pressurised, to provide an internal reservoir of pressurised fluid which when the can is opened will jet gas into the beverage to produce a frothy head thereon comprising:

(1) a first cylindrical shell having an open end a closed end and an annular ledge around its outside surface,

(2) a second cylindrical shell also having an open end and a closed end and having an external diameter such that it can pass over, with clearance, the open end of the first shell to engage the annular ledge for joining thereto,

(3) a small opening in the wall of the second shell to provide an orifice through which beverage can pass to pressurise the interior of the assembled shells and through which gas will jet when the can is opened.

(4) means for retaining the device within a beverage can at a desired position therewithin.

31. A method of constructing a device as claimed in any of the preceding claims in which the device is constructed and assembled in a nitrogen atmosphere so that the device is filled with nitrogen and the small hole is only formed in the wall of the device just before it is inserted into a can or after insertion and just before the can is filled with beverage.

32. A method of constructing a device as claimed in any of the preceding claims, in which the device is formed with the orifice and then purged of oxygen and filled with Nitrogen after being fitted in a can, and the can is then filled with water to at least cover the device until just before filling, when the water is poured out to permit the can to be filled with beverage.

33. A method of filling and processing cans with a beverage which requires pasteurisation after the cans are filled and sealed, and which includes the step of inverting the can before pasteurisation so as to check for leaks when the internal pressure of the can is elevated during pasteurisation, and wherein each can has fitted therein a device as claimed in any one of claims 11 to 29, such that when the can is inverted, the communication between the inner and outer radial compartments within the chamber is now at the bottom of the device, so that during pasteurisation the trapped charge of gas is completely trapped at the top of the chamber and any additional beverage which is driven into the chamber as the temperature and can pressure is raised during pasteurisation, will leave the chamber again as the temperature and can pressure drops during the cooling phase of the pasteurisation cycle so that there is no net gain or loss of beverage as regards the chamber, wherein the gas charge is protected against any leakage during the pasteurisation stage so that when the can is inverted to stand on its base once again, the full gas charge which was trapped in the ring originally will still be available and can communicate via the high level gap over the top of the baffle, with the inner radial compartment within the ring which communicates with the orifice in the chamber wall.