Note: Descriptions are shown in the official language in which they were submitted.
WO 95/09118 PCTYUS94111010
1
Foaming insert for a beverage container
BACKGRO T
S This invention relates to a foaming insert for a beverage container.
There is an expectation for a frothy head to be formed on beer, when this
is poured into a glass, the froth being produced by release of carbon
dioxide dissolved under pressure in the beer. The action of pouring the
beer causes the initiation of gas release to cause a foaming effect to
produce the froth.
It is often required to cause a froth to be formed on opening of the
container, for exampie, where the contents are to be drunk directly from
the container, and it has been known for some years to provide means to
initiate the foaming action as soon as the container is opened and pressure
in the container is released. The usual way to do this is to provide a
secondary compartment in the container containing gas under pressure.
The gas is released through a nozzle, on opening of the main container,
to cause "seeding" of gas release from the container contents.
The contents may, of course, be beverages other than beer and the gas
dissolved in the beverage may be nitrogen as well as carbon dioxide. The
gas provided in the secondary compartment will usually be carbon dioxide,
~ or nitrogen.
An early example of such a container is disclosed in GB-A-1266351
published 1972. The secondary chamber was fixed to the bottom of the
container with a nozzle opening to the container contents. The contents
of the container main chamber and the secondary chamber are in pressure
W0 95109118 PCl'IUS94/11010
2
equilibrium until the main chamber is opened, when differential pressures
causes release of a stream of bubbles from the secondary chamber.
This document discloses that the nozzle may be sealed by gelatine to
permit charging of the secondary chamber with gas prior to filling of the
main chamber with beverage. The gelatine seal is dissolved by the
beverage to open the nozzle, which contaminates the beverage.
The document also discloses the alternative of providing a valve instead
of the gelatine seal, the valve being openable due to pressure differential
when the main chamber is opened.
There have been many developments since, of the principles disclosed in
this document, e.g. as disclosed in GB-A-1331425, W092/00096,
W092/00097, GB-A-2211813, GB-A-2240960, EP-A-0360375, EP-A-
0360373, GB-A-2256628, W091/13006, GB-A-2257132, W091/09781,
GB-A-2183592, GB-A-1588624, W09I/00825, GB-A-2257107 and
W09I/07326.
Some of these documents disclose the principle of charging a separate
insert with gas and providing the insert in the container, prior to filling
the
container. GB-A-2240960 discloses such an insert, which is magnetically
retained beneath the liquid contents of the container.
GB-A-2183592 and W091/07326 disclose, among many proposals, the
provision of a floating insert, which is charged with gas and caused to
float on the beverage, so as to project into the head space. The nozzle is
held below the liquid by weighting of the floating insert.
A disadvantage of the use of a secondary chamber, whose nozzle is open
W0 95109118 PCT/US94111010
3
to the contents of the main chamber prior to opening of the main chamber,
is that a substantial amount of the liquid contents enters the secondary
" chamber. This is caused by changes in pressure due to temperature
changes. The container and its contents are usually subjected to a
pasteurisation step, followed by cold storage.
Where a valve is used, the valve has to remain closed before and after
insertion of the insert in the container and to open only when the container
is opened. One way of achieving this, as disclosed in W091/07326, is to
charge the insert with gas above atmospheric pressure and to maintain the
insert under superatmospheric pressure until the container has been sealed.
This is clearly a difficult procedure to carry out.
The document discloses an alternative of filling the insert at atmospheric
pressure and utilising the pasteurisation step to cause a permanent
reduction in volume of the insert, so that the gas in the insert is
pressurised after insertion in the container.
A further alternative disclosed, is to charge an insert with liquified gas
prior to assembly of the insert. A valve member is held by a resilient
wall in a position closing a nozzle, the pressure, which subsequently
builds up in the insert, acting to urge the valve member in the closing
direction. The pasteurisation step is utilised to deform the insert and
move the valve member to a position, in which it is permanently fixed.
On opening of the container, the resilient wall is caused to release from
the valve member to open the nozzle.
This is a complex arrangement, which is expensive to make so that it will
operate reliably. A further disadvantage is that the valve will reclose as
the pressure difference across the valve reduced, so that only a portion of
21~~741
WO 95/09118 PCT/US9411i010
4
the charged gas is utilised.
Plastics have substantial advantages for ease of manufacture of an insert,
but provide a substantial disadvantage. The whole of a can, including its
insert should be made of the same material to permit recycling.
Plastic causes problems for recycling when inserted in aluminium or steel
cans. The insert should be primarily aluminium, where the cans are
aluminium, but aluminium is also suitable for recycling when used in steel
cans.
~~'CTS OF THF IIyT~JEIyTTfOTy
An object of the invention is to provide a foaming insert for a beverage
container, which overcomes the above disadvantages.
A further object is to provide such an insert, which can be charged with
gas prior to insertion in the container and stored at atmospheric pressure.
A further object is to provide such an insert whose internal pressure can
be increased during the step of pasteurising the beverage in the container
and the increased pressure maintained until the container is opened.
A further object is to provide such an insert which can be cheaply and
easily made.
A subsidiary object is to provide such an insert which floats on the
beverage and is maintainable in a position in which the gas jetting orifice
is submerged in the beverage during jetting. '
A further subsidiary object is to provide an insert with a jetting orifice
W 0 95109118 PCT/US94111010
sealed by a member, which is moisture sensitive, but does not dissolve in
the beverage.
A further object is to provide an insert with a sealing member for its
jetting orifice, which member burst open to provide a sudden escape of
pressure from the insert into the beverage.
A subsidiary object is to provide such an insert which floats on the
beverage and is maintainable in a position in which the gas jetting orifice
is submerged in the beverage during jetting.
A further subsidiary object is to provide such an insert, which may contain
an oxidising gas and does not need to be purged of oxygen.
A further subsidiary object is to provide for uniform jetfing of gas into a
beverage over the jetting period.
The invention provides a foam-inducing insert for inclusion in a container
containing a beverage with gas dissolved under pressure to initiate release
of gas from the container on opening of the container, the insert
comprising:
a housing having a chamber;
gas within the chamber;
~ the chamber having an orifice through the housing;
and closure means closing the orifice and operable under
pressure difference across the orifice caused in use by opening of
the container, whereby gas is jetted into the container;
the closure means comprising a sealing member secured
around the orifice to provide a seal, the seal being burstable under
WO 95109118 PCTIU59a111010
6
said pressure difference.
In one embodiment, the chamber is filled with gas under pressure and the
sealing member is rupturable and moisture-sensitive. The insert can be
stored in dry conditions with the sealing member intact. Within the
beverage container, however, the seating member takes up moisture and
becomes weaker. On opening of the container, the weakened member
ruptures under the sudden pressure drop. The preferred material is an
ethylene vinyl alcohol (EVOH) copolymer.
In an alternative embodiment, the sealing member is adhered around the
orifice by a moisture-sensitive adhesive, such as an EVOH or polyvinyl
alcohol adhesive, which permits dry storage of the insert, but weakens in
the beverage container so that the seal is burst by release of the sealing
member on opening of the container. The sealing member should be
retained on the insert, for example by means of a non-moisture sensitive
adhesive adhering a portion of the member to the housing.
In another embodiment, the sealing member is rupturable (but not
necessarily moisture-sensitive) and is adhered in an inner region around
the orifice by a moisture-sensitive adhesive. The member is more strongly
adhered in an outer region. On opening of the container, the weakened
inner region adhesive releases the member, while the outer region remains
secure. This presents a larger area of the member to the pressure shock
causing rupturing of the member.
Rupture of the sealing member is preferred, since this is highly effective
in nucleating the release of bubbles. This arrangement also permits a
delay to be allowed for, between opening of the container and actual
rupture.
W 0 95109118 '
PCTIUS94111010
7
In a further embodiment, the housing includes a second chamber with a
diaphragm separating the chamber and arrayed so that pressure in the
second chamber is applied through the diaphragm to the first chamber.
The second chamber is pressurised by communication with the interior of
the container.
This communication may be provided by a small orifice, which allows
only slow passage of gas therethrough for slow pressure equalisation
within the container.
Alternatively a larger orifice covered by a gas-permeable film may be
provided.
The second chamber is preferably charged with a non-oxidising gas, such
as nitrogen, to avoid oxidation of the container contents. An oxygen
scavenger may be included in the second chamber for scavenging oxygen
from the headspace in the container. The second chamber could exist only
when pressurised in the container, the diaphragm being initially in contact
with the housing.
To prevent air entering the second chamber during storage of the device,
the orifice is preferably closed by a gas-impermeable rupturable film,
which ruptures under the pressure differential established when the insert
is sealed in a pressurised beverage container.
The diaphragm is preferably made of malleable material, such as soft
aluminium, which collapses in a uniform manner, so as to provide uniform
jetting of gas from the first chamber by the collapsing diaphragm. This
provides controlled nucleation of bubbles over a period, instead of a rapid
decline in pressure, which causes the nucleating effect rapidly declines.
WO 95109118 PCT'/US94111010
8
This arrangement also permits the volume of gas to be jetted to be varied
without changing the external size and shape of the housing. This enables
the same insert placing equipment to be used for different inserts for
different types of beer. The variation is possible by changing the size of
the first chamber, or by adjusting the pressure in the first chamber during
manufacture, relative to that in the second chamber, thereby varying the
size of the first chamber.
The invention also provides a sealed container containing a beverage with
gas dissolved under pressure and with a gas-containing headspace above
the beverage, and an insert in .the container and containing gas under
pressure, the insert having:-
a first orifice positioned to communicate with the container
interior,
a on~way valve closing the first orifice when the internal
insert pressure exceeds the container interior pressure and openable
when the container interior pressure exceeds the internal insert
pressure,
a second orifice positioned to communicate with the
container interior,
a birstable seal held in a position closing the second orifice
and adapted to resist opening under differential pressures across the
valve generated during pasteurisation of the container and its
contents,
the burstable seal being openable under the differential
pressure created on opening of the container to release the insert
contents through the second orifice.
This arrangement enables the insert to be charged with gas and stored at
atmospheric pressure, with the valve preventing gas leakage.
*rB
2~1~7~1
WO 95/09118 PCTIrTS94111010
9
The charging pressure can be increased during the pasteurisation of the
beverage. The valve opens as the pressure increases during pasteurisation
and recloses as the pressure drops on cooling. During this procedure,
- gas, beverage, or a mixture from the container, enters the insert and is
retained in the insert. The valve remains closed after the container is
opened and gas or gas/beverage mixture is jetted solely through the second
orifice.
It is preferred that substantially only gas is jetted through the second
orifice. This is attained by ensuring that the first orifice communicates
only with the headspace. It is also preferred that the second orifice is
submerged in the beverage when and shortly after the container is opened,
so that the gas is jetted into the beverage. This arrangement provides the
best conditions for initiation of foaming, with optimum use of the insert
internal volume.
It is also preferred that the insert f<oats in the beverage, since this avoids
the need to mount the insert in a fixed location in the container.
Another aspect of the invention, as described hereafter, enables the
floating insert to be orientated to ensure that the contents of the insert are
jetted into the beverage and not the headspace.
The invention also resides in an insert for insertion in a container
containing a beverage with gas dissolved under pressure, prior to sealing
of the container, to initiate release of gas from the container on opening
' of the container, the insert comprising:-
gas under pressure contained in the insert,
a first orifice closed by a one-way valve when the internal
pressure exceeds the external pressure,
WO 95109II8 PCTIUS94/11010
a second orifice spaced from the first orifice and closable by
a burstable seal held closed against the pressure differential between
the internal pressure and atmospheric pressure and against a
predetermined pressure differential,
the burstable seal being openabIe when said predetermined
pressure differential is exceeded.
The invention also provides a method of producing a sealed container
containing a beverage with gas dissolved under pressure and an insert in
IO the container containing gas under pressure, which gas is released on
opening of the container, the method comprising.
charging the insert with gas under pressure through a first
orifice, the insert having a one-way valve which is urged to close
the first orifice when the internal insert pressure exceeds the
external pressure,
providing the insert with a second orifice and a burstable
seal which is held closing the second orifice and withstands the
pressure differential between the internal pressure and the external
pressure,
inserting the insert into a container containing the beverage
and sealing the container,
exposing the sealed container to pasteurising conditions such
that the pressure in the container is increased and communication
occurs through the first orifice between the insert and the container
interiors, and
cooling the sealed container, so that the valve closes to
maintain the increased pressure in the insert,
the burstable seal also withstanding the pressure differentials
during the pasteurising and cooling steps,
the burstable seal being openable under the differential
W 0 95109118 PCT/US94111010
11
pressure produced on opening ofthe sealed container.
The one-way valve may be dispensed with, if the first orifice is made
- substantially smaller than the second orifice. With this arrangement, the
interior pressure of the insert will equalise after pasteurisation and during
storage with that of the container, due to the communication through the
first orifice. The provision of the valve, however, permits use of a
relatively high internal pressure in the insert and hence the insert may
have a smaller volume.
The burstable seal, which closes the second orifice, may be designed to
open when there is an abrupt reduction of pressure on opening of the
container. There will still be a sudden pressure differential across the seat
and jetting of gas through the second orifice, because venting through the
smaller first orifice will be slow.
The advantage of orienting the floating insert, with its jetting orifice
submerged in the beverage, is referred to in GB-A-2183592. The only
disclosure, however, is briefly to weighting the insert. W091/07326
describes and illustrates a weighted, floating insert, wherein the insert is
made of a plastics material.
Plastics have substantial advantages for ease of manufacture of an insert,
but provide a substantial disadvantage. The insert should be made of a
material which permits recycling.
' Aluminium and steel cans are commonly used and the insert should, be
made of aluminium for recycling purposes. Aluminium is an expensive
material and needs to be sparingly used resulting in a lightweight insert.
" ,
WO 95109118 > PGT/US9411I010
12
It has now been found that, if the metal insert is sufficiently light, the
reactive force generated on the insert as the gas jets from the insert can
propel the insert towards the top of the container. IL is, therefore,
preferred that the dimensions of the floating insert parallel to the container
axis are sufficiently great relative to the headspace depth, to ensure that
the jetfing orifice remains submerged. This problem would not usually
arise with plastics inserts.
If the insert is sufficiently light, the angular alignment of the insert can
be
determined by contact between the inner surface of the top of the can and
the top of the insert and such contact could cause the jetting orifice to
open into the headspace. This is avoided according to one aspect of the
invention by ensuring at least three point contact between the contacting
surfaces.
Floating stability of the insert is also important to ensure that the insert
remains in the desired position. The problem of angular alignment would
be alleviated by use of a large insert of relatively shallow depth, but such
an insert would be stable in an inverted floating position and also be tilted
on opening of the container by projection of a hinged opening member
into the interior of the container.
The various constraints, including gas capacity, means that an elongate
insert is preferred, which floats with its Longitudinal axis generally upright
and has the at least three point contact feature, so that the jetting orifice
is always submerged.
Weighting is provided, below the liquid level, to tilt the floating cylinder
towards a vertical position. Plastics "weights" with a plasfics insert would
not achieve this effect, due to the low density of the plastics material.
WO 95/09118 PCT/U594111010
13
It has been found that with these constraints, the weighting of the insert
can be reduced, so that the insert floats generally upright, but with its
longitudinal axis at an acute angle to the vertical. For a cylindrical insert,
this angle should be B or less, where:-
B = tan-' R/L
where R is the radius of the cylinder, L is the distance from the upper
face of the cylinder to the point where the vector of buoyancy intersects
the axis of the cylinder. The vector of buoyancy is colinear with the
weight vector.
It is preferred that the insert is then caused to float in a given rotational
orientation by asymmetric weighting of the insert, with the jetting orifice
spaced from the longitudinal axis towards the region of maximum
weighting.
In another embodiment, liquid is contained in the insert to reduce the
amount of aluminium weighting required.
The above calculation was made on the assumption that an added weight
of solid aluminium of the form of a circular disc was joined to the original
cylinder at its lower end. If this same disc of aluminium is rigidly
attached in such a way that its own center of mass is located at a distance
from the lower end of the original cylinder, less added mass will be
required.
Similarly, if the lower portion of the hollow cylinder is filled with liquid
rather than gaseous product, less added weight will be required.
The problem of the insert being jetted against the top of the container can
be prevented by reducing the diameter of the jetting orifice, although this
CA 02178741 2004-07-22
69179-82
14
may affect the nucleation effect of the jetted gas in the beverage. The
critical maximum diameter can be determined by:
CriticalDiameter5 4 x Wt
n x Pressrun
It is important to prevent oxygen from contacting the beverage in the
container, since this may lead to spoilage. It has been necessary to be
careful to purge inserts of oxygen prior to filling and closing of the
container. One reason for this is that inserts have been made of plastics
materials, which are gas permeable, as disclosed in W091 /07326, so that
oxygen could permeate to the beverage. In some inserts, which have an
orifice open to the beverage, oxygen could also pass from the insert to the
beverage through the orifice.
The use of aluminium for the body of the insert, coupled with the
provision of a valve for closing the insert interior to the beverage
overcomes this disadvantage. It is possible for the gas in the insert to
include oxygen, since this cannot escape from the insert to the beverage,
until the container is opened. Where the insert has two valves, as
described above,~the one-way first valve, which closes when the container
interior pressure is less than the insert interior pressure, prevents escape
of oxygen from the insert. The insert could therefore be filled without
protection in air.
CA 02178741 2004-07-22
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14a
In accordance with another aspect of the present
invention there is provided a foam-inducing insert for
inclusion in a container containing a beverage with gas
dissolved under pressure to initiate release of gas from the
insert on opening of the container, the insert comprising: a
housing having a chamber, the chamber having a jetting
orifice through the housing; and a closure means closing the
orifice and openable under pressure difference across the
orifice caused in use by opening of the container, the
closure means including a sealing member secured around the
orifice to provide a seal and the closure means being
burstable under said pressure difference, the sealing member
being rupturable and moisture-sensitive, so that it
withstands greater pressure in its dry state than after
exposure to moisture; and a gas within the chamber.
In accordance with another aspect of the present
invention there is provided a foam-inducing insert for
inclusion in a container containing a beverage with gas
dissolved under pressure to initiate release of gas from the
insert on opening of the container, the insert comprising:
a housing having a chamber, the chamber having a jetting
orifice through the housing; and a closure means closing the
orifice and openable under a pressure difference across the
orifice caused in use by opening of the container, the
closure means includes a sealing member secured around the
orifice to provide a seal and the closure means being
burstable under said pressure difference, the sealing member
is adhered around the orifice by a moisture sensitive
adhesive whose adhesive properties reduce on exposure to
moisture; and a gas within the chamber.
CA 02178741 2004-07-22
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14b
BRIEF DESCRIPTION OF DRAWINGS
Fig 1 is a sectional view through a sealed,
beverage can including a
CA 02178741 2004-07-22
69179-82
floating insert according to the invention;
Fig 2 is a sectional view of a first embodiment of an insert according to
the invention;
5
Fig 3 is a diagrammatic view of a sealing strip of the insert of Fig 2;
Fig 4 is a diagrammatic view of an alternative sealing strip for the insert
of Fig 2;
Fig 5 is a view on the line 5-5 of Fig 4;
Fig 6 is a diagrammatic view of an alternative sealing strip;
Fig 7 is a sectional view of a further embodiment of an insert according
to the invention;
Fig 8 is a diagrammatic view of a closure strip for the insert of Fig 7;
Fig 9 is a view similar to Fig 7, showing a diaphragm partially collapsed
after pressure-charging of the insert in a beverage can;
Fig 10 is a view similar to Fig 9, showing the diaphragm fully collapsed
after opening of a beverage can;
Fig 11 is a sectional view of a further embodiment of an insert of the
invention;
Fig 12 is a sectional view on line 11-11 of Fig 11;
CA 02178741 2004-07-22
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16
Fig.13 is a sectional view of a modification of the insert of Fig. ll;
Fig.l4 is a sectional view similar to Fig.l2, of an insert with a modified
form of control valve, with.the valve in its closed position;
Fig.lS is a view similar to Fig.l4 showing the modified control valve in
open position;
Fig.l6 is a view similar to Fig. l4, showing a modified aligning weight;
Fig.l7 shows a view similar to Fig. l l of a modified insert, which floats
in a canted orientation;
Fig.l8 shows a view similar to Fig.l7 of a modified insert containing
liquid;
Fig.l9 shows a view similar to Fig.l7 of an insert with a modified
aligning weight and repositioned jetting orifice;
Fig.20 shows a view similar to Fig.l9 of an insert with a modified upper
end;
Fig.21 is a graph plotting force against elongation from a tensile strength
test carried out on a dry EVOH film;
Fig.22 is a graph, similar to Fig.2l, for a similar film, which has been
soaked in beer, the film being at room temperature; and
Fig.23 is a graph, similar to Fig.22, for a similar film, which has becn
soaked in beer, the film being at about 2°C.
wo 9sio9aas 2 ~ ~ ~ 7 41 p~~s9maaoao
16.1
There is shown in Fig.I a container in the form of an elongate,
S cylindrical, metal can 11 of conventional design, containing a carbonated
beverage 12, such as beer. The can I I is closed by a lid 13 peripherally
secured to the can to seal the can, the lid 13 being provided with a
conventional, sealed, openable tab 14. A headspace 15 is provided
between the upper surface 16 of the beverage I2 and the lid 13. The
21 ~~?~~ 1
WO 95/09118 FC1YUS94I11010
17
inner surface 18 of the lid has a slight concave dome shape, in
conventional manner.
An insert 20, containing gas under pressure, is provided in the can and
floats in the beverage 12 with a lower portion 20a submerged and an
upper portion 20b extending into the headspace 15.
The insert 20 is more clearly shown in Fig 2 and comprises a hollow
housing 21 having a body 22 of inverted cup shape, closed by a disc 23.
The body 22 is made of a rigid aluminium alloy and the disc may be of
a heavier metal, or carry a weighted portion for weighting the insert, so
that it will float on liquid with the disc below the liquid surface. Other
materials, such as plastics may be used for the housing.
The disc has an orifice 25 for jetting of gas from the interior of the
housing into liquid in the can 11.
The orifice 25 is closed by a sealing member 26, which may be directly
secured to the disc 23 to form a burstabIe seal. Preferably, however, a
substrate 27 (Fig 3), provided with a jetting orifice 28, is secured to the
disc 23, with the sealing member 26 secured to the substrate.
The sealing member comprises, in one embodiment, a rupturable plasfics
strip 26 adhered to the substrate 27 by adhesive 29 around the orifice 28.
A region 30 of the strip adjacent the orifice 28 is left unadhered to the
disc.
The strip 26 comprises a moisture-sensitive material, whose rupture
strength reduces after exposure to moisture. The housing is pre-charged
with gas under pressure.
2 i T~74 i
WO 9S/09118 PGT/US94/11010
18
The strip 26 has sufficient rupture strength to permit prolonged storage of
the insert in dry conditions. Within the can, however, the exposure to the
- can contents weakens the strip. The differential pressure across the strip
in the can is insufficient to rupture the strip, but the sudden drop in
- 5 pressure, on opening the can, causes rupture and the seal bursts open to
permit jetting of gas into the can contents.
The strip 26 may be made of an ethylene vinyl alcohol (EVOI~
copolymer film. The copolymer preferably includes 40~ or less of
ethylene monomers and in one example comprises 32% ethylene
monomers. A suitable material is commercially available as type EF-XL.
This film is 15 microns thick and is biaxially oriented.
The unadhered region 30 of the strip using this material and an internal
gas pressure of 3 atmospheres is 2mm in diameter (about 3mma).
This construction was found to be storable in the dry state. When left in
a can filled with beer containing carbon dioxide and nitrogen under
pressure, the sealing strip remained intact, but, on opening the can, the
strip ruptured in the unadhered region 30.
Plastics material lose strength during storage under stress and may suffer
creep rupture and it is important to choose a material for the sealing strip,
which loses less strength for this reason, during dry storage, than due to
moisture sensitivity. The material disclosed above meets this requirement
and it is believed that the biaxial orientation reduces the tendency to creep
rupture. It is preferable to store at low temperatures to reduce this
w0 95109118 PCT/US94I110E 0
19
tendency.
The creep rupture property may be utilised to provide a delay in rupture
after opening of the container. The sealing strip is arranged so that it
stretches under the differential pressure and suddenly ruptures after a
second or more delay.
The EVOH sealing strip is temperature sensitive and has a greater rupture
resistance when cold. This property prevents premature opening of the
sealing strip as disclosed later in this description.
The EVOH layer may be coated, or laminated, with a film which reduces
its moisture sensitivity. This also helps to prevent premature opening, by
delaying the strength reduction until the pressure in the can has built up.
by escape of gas from the beverage.
The general relationship between internal pressure, the area of unadhered
region and the strip thickness is as follows:
PA~/t = 0.35
wherein P = gauge pressure in atmospheres
A = unadhered region in mm2
t = film thickness in microns
The housing may be charged with air, avoiding the need for using a non-
oxidising gas, since EVOH, even after moisture expansion has good gas
barrier properties, so that oxygen will not appreciably pass into the can
and spoil the contents.
In a modification, a non-moisture sensitive strip 26 may be used, the seal
WO 95/09118 ~ pCT/ITS9~1111010
being burstable by use of a moisture sensitive adhesive 29, e.g. an EVOH
adhesive, which releases the strip to uncover the aperture.
In a further embodiment, as shown in Figs 4 and 5, a rupturable strip 35
5 is adhered to the substrate 27 in two regions. A moisture-sensitive EVOH
adhesive is used to adhere the strip 35 to an inner annular region 36 of the
substrate around the orifice 28. An outer, annular adhesive region 37
provides greater adhesion. This is provided by using a stronger, non
moisture sensitive adhesive, or the same adhesive over a substantially
10 larger area.
In use, on opening the can, the strip 35 is released at the inner region
exposing a larger area of the strip to the differential pressure caused, so
that the strip bursts.
The sealing may be provided on a bush, secured in an aperture in the
insert, the bush being provided with the jetting orifice.
The insert according to any of the above embodiments can be easily
recycled along with the can. There is no necessity to purge the insert of
oxygen and no need to store, or ship in an oxygen free environment.
A further embodiment of the invention shown in Fig 6 avoids the necessity
for precharging with pressurised gas and the necessity to store in a
moisture free environment.
In this embodiment, a thin, burstable gas-impermeable layer 60 is
provided between the substrate 27, having the jetting orifice 28, and the
disc 23 of the insert body. The sealing strip 61 is made of gas-permeable
material and the substrate is also preferably gas permeable. The sealing
W0 95/09118 PGTIUS94/11010
21
strip 61 is rupturable and is adhered to the substrate 27 by a ring of
adhesive, which may be moisture sensitive, as described above.
In use, the insert is filled with an oxidising gas, such as air, substantially
at atmospheric pressure.
With the insert provided in a closed beverage can, gas under pressure in
the can passes through the permeable layers, so that pressure builds up on
one side of the gas barrier layer 60. The pressure build up eventually
ruptures the gas barrier layer, so that pressure can equalise across the
sealing strip 6I.
The sealing strip 61 ruptures due to the sudden drop in pressure on
opening of the can.
In a modification, the arrangement shown in Fig 2 is modified by
provision of a gas barrier layer on the internal face of the disc 23 of the
insert body, the jetting orifice being in the disc instead of a substrate, as
in Fig 6.
In a further embodiment, shown in Fig 7, the insert has a housing 121
with a body 122 and disc 123, as in the previously described
embodiments.
The insert includes an internal diaphragm 150, which is cup-shaped and
divides the body interior into upper and lower chambers 151,152. The
diaphragm is collapsible, but sufficiently rigid to maintain the cup shape
unless subjected to collapsing forces. It may be made, for example, of a
soft aluminium alloy.
w0 95/09118 2 1 7 8 7 4 ~ PC1YUS94/11010
22
The disc 123 has a jetting orifice 125 closed by a sealing member 126 and
the lower chamber 152 contains a gas, which may be air, under
atmospheric, or Iow pressure.
The upper chamber 15I has a charging orifice 160 in the top of the
housing and closed by a closure strip 161. This chamber contains a non-
oxidising gas, such as nitrogen, at atmospheric pressure or a little below
atmospheric pressure. The closure strip 161 comprises two superimposed
layers, which are weakly adhered to each other. The outer layer 162
comprises a gas-permeable material, whereas the inner layer 163
comprises a rupturable gas-impermeable material.
After the insert has been placed in a sealed can of beverage, the gas under
pressure in the can will permeate through the outer gas-permeable layer
162 and the inner layer 163 will be caused to rupture due to the pressure
differential across the layer. The gas will then pass through the charging
orifice 160 to pressurise the upper chamber 151.
This pressure is transferred through the diaphragm 150 to the lower
chamber 152, this diaphragm beginning to crush, so that the pressure in
the lower chamber almost equalises with that in the upper chamber. The
partially crushed diaphragm and ruptured layer 163 are shown in Fig 9.
On opening of the can, the sudden pressure drop across the sealing strip
126 causes it to rupture and gas is jetted from the lower chamber into the
can.
During jetting, the diaphragm crushes as the pressure in the lower
chamber drops relative to that in the higher chamber. All of the gas is
jetted at a significant pressure providing a generally uniform jetting rate
CA 02178741 2004-07-22
69179-82
23
over the jetting period. This crushed diaphragm and ruptured sealing strip
126 are shown in Fig.lO.
Some gas under pressure remains in the upper chamber at the end of the
jetting period, but this is dissipated through the gas-permeable layer 162
of the closure strip 161.
It is not essential for an insert operating in this manner to float in the can
and the insert could be filed, if desired, below the liquid level.
With a floating insert, however, it is possible for the closure strip 161 to
be dispensed with, if the orifice 160 is made very small, so that gas can
pass only slowly through the orifice.
It is, however, still preferred to provide a burstable seal, e.g. by means
of a rupturable layer covering the orifice. This will prevent oxygen from
entering the insert during storage.
The rupturable material for the sealing strip 126 and the rupturable layer
163 of the closure strip 161 may be a high gas-barrier polymer such as
EVOH, polyvinylidene chloride, polyamide or polyester, or may have two
or more layers including a gas-barrier layer. Other possible materials
include thin metal foil, or metallised plastics film, or inorganic oxide
coated plastics film, such as silicon oxide applied by vapour deposition.
The gas-permeable layer 162 may comprise low density polyethylene, an
ionomer such as Surlyn, cellulose acetate butylate, or a porous plastics
paper such as Tyvek.
Similar materials may be used in the embodiment of Fig 6.
*Trade-mark
w0 95109118 ~ ~ ~ ~ v ~ PCTIU594/110I0
24
The upper chamber 151 may include an oxygen scavenger.
Potassium sulphite is often used in cans of beer for this purpose, but,
being soluble in beer, it spoils the flavour and contaminates the beer. If
placed in the can, it will also scavenge oxygen from the air during the
handling and filling procedures before the can is sealed.
The provision of an oxygen scavenger in the upper chamber 151 means
that it never comes into contact with fhe beer and is sealed from the
atmosphere during handling by the closure strip 161. Oxygen is
scavenged within the upper chamber without contact with the beer.
In a further embodiment (not shown) the diaphragm is omitted and the
whole interior of the insert is allowed to get its pressurisation from the
IS beverage. The charging orifice may be closed by providing the burstable
gas barrier film in the interior of the insert and the gas permeable film on
the exterior of the insert.
If a very small charging orifice is provided, the gas permeable film may
be omitted.
Another embodiment of an insert 220 is shown in Figs. I I and 13 and
comprises a hollow, elongate, cylindrical body 221 closed at both ends by
upper and lower end walls 222,223. Other shapes for the body may be
used.
' The insert includes a disc-shape aligning weight 224 secured internally of
the body to the lower wall 223, so that the body floats with its axis
vertical. The weight may be made of metal, for example. The body may
be a plastics moulding, but is preferably made of metal, such as
wo vsro9ms 2 ~ ~ ~ ~ ~ ~ Pcrms9antoio
aluminium.
The cylindrical wall 226 of the body has a charging orifice 227 in the
upper portion 220b of the insert, so as to be positioned to communicate
5 the interior of the body with the headspace 215. The charging orifice is
closed by a one-way valve 228, in the form of a flap valve. The valve
may be defined by a flexible strip adhered at one end 228a to the interior
surface of the cylindrical wall 226, with the remainder of the strip being
hingeable to close or open the orifice. This arrangement is such that the
10 valve is urged to the closing position when the interior pressure exceeds
the exterior pressure and opens only when the exterior pressure exceeds
the interior pressure.
The lower end wall 223 of the body is provided with a jetting orifice 230
15 and the aligning weight 224 has an aperture 225 permitting communication
of the orifice 230 with the interior of the body. The jetting orifice 230 is
closed by a rupturabIe member 231 in the form of a strip adhered to the
exterior surface of the lower end wall 223 about the orifice. The orifice
is openable when the internal pressure of the body is greater than the
20 external pressure and the pressure differential exceeds a predetermined
threshold. This may be determined by structuring the strip, so that it
ruptures when the threshold is exceeded. This may be achieved by
adhering the strip in a manner such that a sufficient area is not adhered
around the orifice. With a heat and pressure sensitive adhesive, for
25 example, the non-adhered area can be determined by non-application of
heat and pressure at that area. Alternatively, the adhesive may fail when
the threshold is exceeded, so that the member is blown away from the
jetting orifice, forming a destructable seal.
Fig 412 shows a modified construction of the rupturable member. The
WO 95/09118 PCTlUS94/11010
26
strip 23IA is trapped between the aligning weight 24A and the bottom
wall 223A of the insert. The weight 224A has a small orifice 225A
forming the jetting orifice and the bottom wall 223A has a larger aperture
230A to permit rupture of the strip 231A at the desired threshold pressure.
S The strip 231A may be held by compression between the weight and the
bottom wall or may be adhered to either or both of the weight and the
bottom wall.
This modification ensures a clean, predictable rupture of the strip at the
threshold pressure.
The threshold is determined, so that the control member 231 will remain
closed until the can is opened, the threshold only being exceeded in that
circumstance.
In use, the insert 220 is charged with a pressurised gas through the
charging aperture 227. After charging, the gas is retained in the body of
the insert, by automatic closure of the one-way valve 228, with the
external pressure being atmospheric pressure.
The charged insert is inserted into a can I1 prior to filling with beverage
12, so that the insert floats on the beverage. The can lid 13 is secured in
place. The weighting of the insert causes it to float with the control
member 231 submerged in the beverage and the charging valve 228
exposed to the headspace 15.
The filled can is then subjected to pasteurisation, which causes an increase
in pressure in the can. The one-way charging valve 228 opens when this
pressure exceeds that in the body of the insert to permit gas from the
headspace 15 to enter the insert. The can is then cooled and the one-way
WO 95109118 PCT/US94111010
27
valve 228 recloses maintaining an increased internal pressure in the insert,
as the can cools down.
The control member 231 is constructed to withstand the pressure
differentials caused by the pasteurisation and cooling steps.
On opening of the can at 14, there is a sudden drop in pressure in the can.
This creates a pressure differential across the member 231 sufficient to
exceed the threshold, so that the member is permanently opened and gas
is jetted through the orifice 230 into the beverage.
The present inventor has discovered that this jetting action may cause the
insert 220 to be forced away from the beverage 12, so that it contacts the
lid 13. In order to ensure that the gas is jetted into the beverage 12, and
not the headspace 15, the length of the insert 220 is made sufficiently
large relative to the depth of the headspace, that the jetting orifice remains
submerged when this happens. The outer surface of the upper end wall
222 is also made flat so that there is peripheral contact with the inner
surface ,218 of the lid 13. This arrangement does not cause angular
movement of the insert, which could bring the jetting orifice into
communication with the headspace.
When the insert body is made of aluminium, it will be coated against
corrosion. Forming of the orifices 227,230 produces corrodible edges.
The edge of the jetting orifice 230, however, is protected from corrosion
by the strip 231. The edge of the charging orifice 227 is less likely to
corrode, being exposed only to the headspace 15.
A modification of the control member is shown in Figs. 14 and 15. The
lower end wall 223 of the body is replaced by a domed wall 323 having
W0 95109118 PCrlUS94/11010
28
the jetting orifice 330. The aligning weight 224 is mounted below the
domed wall by a skirt 325 leaving a gap between the domed wall and the
weight. The convex side of the dome faces the interior of the insert.
S The control member is a domed cap 33I having a central concave region
335 complementary to and lightly adhered to the convex side of the domed
wall, so as to close the jetting orifice 330. The peripheral region 336 of
the cap 331 is non-circular and is shaped to prevent snapping of the dome
from the stable concave state to a convex state.
The domed wall 323 is constructed so that it snaps from the convex state
shown in Fig. I4 to the concave state shown in Fig.lS when the
predetermined pressure differential threshold is exceeded. This releases
the cap 331 from the domed wall and opens the jetting orifice. The
threshold can readily be determined by the person skilled in the art using
well known formulae including the elastic modules of the domed wall
material, its thickness and radius of curvature.
The non-circular shaping of the peripheral region 336 of the cap ensures
that, if the cap turns over, it cannot seal the orifice in the Fig. l4 state.
A further modification is shown in Fig.l6. In this modification, the
weight 324 is provided closer to the domed wall 323 and is shaped with
a concave surface 340 to accommodate the domed wall when it flips over
to its alternate state.
The insert may be permitted to float with its longitudinal axis at an acute
angle to the vertical V, as shown in Fig.l7. This is especially useful
where the body of the insert 420, and the weight 424, are made of
aluminium, so that the amount of aluminium used can be reduced.
WO 95/09118 ~ PCTlUS94111010
29
The insert floats at an angle B to the vertical V and has a flat top surface
422 for contacting the interior of the lid of the can when the insert is
propelled against the lid by the jetting force.
The jetting orifice remains below the surface of the liquid in the floating
orientation of the insert and engagement of the flat surface 422 with the
lid orients the insert longitudinal axis closer to the vertical on opening the
can, so that the orifice remains below the liquid surface.
The weight 524 may be reduced still further, as shown in Fig. l8, if some
liquid 530 is provided in the insert.
If one desires to jet a large quantity of liquid, one places the charging
orifice below the liquid level. It should be noted that the level of liquid
fill in the insert, which is achievable in this way is not limited to the
insert
height position corresponding to the original level of the liquid product in
the primary container. One reason for this is that as the insert fills with
liquid, its buoyancy will be reduced and the insert will sink lower into the
liquid. The other reason is that liquid will flow into the insert until the
gas pressure over the liquid in the insert is equal to that inside of the can.
If desired, one can moderate the level of liquid within the insert by having
two charging orifices, one below the liquid level in the can, and one above
that level.
A further embodiment is shown in Fig. l9. The insert 620 has a similar
construction to that of Fig.l7 with a weight 624. In this embodiment,
however, the total weight is made asymmetrical about the longitudinal
axis. This is achieved by an additional weight 640 positioned at a specific
circumferential location near the bottom of the insert. An asymmetrical
disc could be provided instead. The additional weight 640 predetermines
R'O 95/09118 PC1YUS94111010
the rotational orientation of the insert, when the latter is floating at the
angle B to the vertical V.
The jetting orifice 630 is provided offset from the longitudinal axis
5 towards the position of the additional weight 640. This means that the
orifice is positioned at a deeper location than if the insert floated at a
vertical orientation.
A modification of the embodiment of Fig.l9 is shown in Fig.20. In this
10 embodiment, the upper end 722 of the insert 720 is angled relative to the
bottom end 723, so that the upper end is horizontal in the floating
orientation of the insert.
When the insert is propelled against the lid, the floating orientation is,
15 therefore, maintained.
This permits the insert to be shorter relative to the headspace than in the
embodiments of Figs. I I or 19.
20 The position of the insert relative to the liquid surface during charging
in
the pasteurisation step is determined by its buoyancy and its position
during jetting is determined by its longitudinal dimension relative to the
headspace. If one wants to have the insert partially filled with liquid and
later jet that liquid above the product liquid level, it is possible by
25 reducing the buoyancy of the insert to the point where the charging orifice
is covered with liquid during charging and providing sufficient headspace
height to allow the insert to elevate in reaction to its jetting action. In
this
way, one can form a foam in that liquid near the surface while the rest of
the liquid retains its inherent sparkle.
W0 95109118 ~ ~ ~ ~ ~ ~ ~ PCd'ICTS94111010
31
In a modification, the one way valve 228, shown e.g. in Fig.l l, may be
omitted. In this modification, the charging orifice 227 is made of smaller
area than the jetting orifice 230, so that the loss of pressure through the
charging orifice 227, on opening of the container, is insufficient to prevent
opening of the control member 231 and jetting through the jetting orifice
230.
In this modification, the internal pressure of the insert will be relatively
low, since it will equalise with the internal pressure in the container.
The diameter of the jetting orifice may, for example, be 0.8 mm and that
of the charging orifice O.lmm. The loss of gas through the charging
orifice, on opening of the container, would be only 2~ with this
arrangement.
There should be substantially no oxygen in the insert in this modification,
because the oxygen could diffuse through the charging orifice to the
container contents. the insert would, therefore, preferably be filled in a
non-oxidising atmosphere and protected from diffusion of oxygen into the
insert until it is to be placed in the container. With a small charging
orifice, significant diffusion would take several minutes, so protection
during placement in the container and closure of the container would not
be necessary.
The insert could be protected during shipping and storage by oxygen-
barrier packaging or blocking of the charging orifice by oxygen-barrier
tape. The packaging could comprise a bag containing a number of inserts
and an oxygen scavenging agent.
WO 95/09115 217 8 7 ~ 1 PCTJUS9~111010
31.1
The inserts are exposed to moisture within the can for a substantial period
after sealing, until the pressure builds up, due to release of gas from the
liquid. The filling procedure is carried out at low temperatures to retain
a high gas content in the liquid. This means that the moisture sensitive
layer is exposed to both moisture and a high pressure differential for some
time until the pressures equalise. It would, therefore, be expected that a
moisture sensitive layer would become weak during such exposure to
pressure and moisture and burst before the temperatures were equalised.
It has been found, however, that EVOH is relatively moisture-insensitive
at such low temperatures, so that the expected problem does not arise.
The EVOH layer takes up moisture at higher temperatures and so reduces
in strength only after the pressures have equalised.
Examale
An insert was made as disclosed with respect to Figure 2, having a strip
26 made with EF-XI, as disclosed with respect to that figure.
The insert was placed in an empty can body, which was then filled with
beer at a temperature of about 2°C. Within a few seconds of filling, a
lid
was sealed to the can body. The can was subsequently inverted and
pasteurised at 60°C for about IS minutes and then cooled to about
7°C
and stored at this temperature.
The can was subsequently opened and the film burst immediately on
opening creating foam within the can.
Upon pouring the beer from the can into a glass, the entire beer contained
small bubbles, which produced a foam on the beer typical of that produced
by a draught-type beer.
WO 95/09118 PCT/US94111010
31.2
Fig.21 shows a dry EF-XI, film subjected to a tensile strength test at room
temperature. The film exhibited a slow increase in elongation with
increasing force up to about 55 mPa.
Fig.22 shows results of the same test carried out on a wet EF-XI, film,
which had been soaked in beer, at room temperature. The film exhibited
a slow increase in elongation only up to about 20 mPA, showing the
substantial reduction of strength relative to a dry film.
Fig.23 shows results of the same test carried out on a wet EF-XL film at
about 2°C. The film had again been soaked in beer. The film exhibited
a slow increase in elongation up to about 55 mPA, which illustrates that
the strength of the wet film at low temperatures is comparable with that
of a dry film.
