U.S. patent application number 09/880955 was filed with the patent office on 2001-11-15 for fluid containers.
Invention is credited to Searle, Matthew J..
Application Number | 20010039947 09/880955 |
Document ID | / |
Family ID | 10844348 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010039947 |
Kind Code |
A1 |
Searle, Matthew J. |
November 15, 2001 |
Fluid containers
Abstract
A closure (30) for a container is designed to facilitate the
mixing of a first material within the container with a second
material within the closure at the point of use. The first and
second materials are generally chemically reactive. The plastics
material closure (30) has a base (32) and a lid (34). The base
(32), which is circular, has an annular peripheral rim (36)
defining an annular recess (38) by which the closure (30) may be
clipped onto a container (10). Radially inwardly of the rim (36) is
an upstanding peripheral wall (40) defining a chamber (42) for
containing the second material. A plunger (44) is affixed to the
base (32) centrally of a convex button (50). When mixing of the
first and second materials is required, the container (10) is
positioned so that the base (32) of the closure is uppermost, and
the button (50) is pressed to move the plunger (44) to push the lid
(34) out of the opening of the chamber (42).
Inventors: |
Searle, Matthew J.; (Bruton,
GB) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
8th Floor
1100 North Glebe Road
Arlington
VA
22201-4717
US
|
Family ID: |
10844348 |
Appl. No.: |
09/880955 |
Filed: |
June 15, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09880955 |
Jun 15, 2001 |
|
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PCT/GB99/04241 |
Dec 15, 1999 |
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Current U.S.
Class: |
126/263.02 ;
126/263.05; 126/263.06; 126/263.08; 126/263.09; 62/4 |
Current CPC
Class: |
B65D 81/3222 20130101;
A47J 36/28 20130101; B65D 81/3484 20130101; B65D 2205/00
20130101 |
Class at
Publication: |
126/263.02 ;
126/263.05; 126/263.06; 126/263.08; 126/263.09; 62/4 |
International
Class: |
F24J 001/00; F25D
005/00; F24J 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 1998 |
GB |
9827718.9 |
Claims
1. A fluid container for use as a closure, the fluid container
comprising a base, a peripheral wall upstanding from the base and
defining a chamber for containing fluids, the free end of the
peripheral wall defining an opening of the chamber, and a lid
received within said opening to tightly close said chamber, and the
fluid container further comprising means operable by pressing the
base to push the lid out of its tightly closed position to enable
exit of fluid from the chamber.
2. A fluid container as claimed in claim 1, wherein the closure is
arranged to clip onto a receptacle to close a cavity therein.
3. A fluid container as claimed in claim 1 or claim 2, wherein the
base of the fluid container is provided with a peripheral rim, and
said upstanding peripheral wall is arranged on the base inwardly of
the peripheral rim.
4. A fluid container as claimed in claim 3, wherein said peripheral
rim is appropriately shaped to clip onto a receptacle to close a
cavity therein.
5. A fluid container as claimed in claim 3 or claim 4, wherein the
fluid container is circular, and the peripheral rim is annular.
6. A fluid container as claimed in claim 5, wherein an annular
groove is defined in the base, radially inwardly of the peripheral
rim.
7. A fluid container as claimed in any preceding claim, wherein the
fluid container is circular, and wherein the peripheral wall is
arranged radially inwardly of the peripheral rim and defines a
substantially cylindrical, fluid containing chamber.
8. A fluid container as claimed in any preceding claim, wherein
said lid snap fits into the chamber opening.
9. A fluid container as claimed in any of claims 1 to 7, wherein
the periphery of the lid is formed with an upstanding rim arranged
to engage within the opening of the chamber.
10. A fluid container as claimed in claim 9, wherein the inner
surface of the lid and its peripheral rim are shaped such that any
increase in the pressure of the fluid within the chamber tends to
urge the rim into closer contact with the opening of the
chamber.
11. A fluid container as claimed in claim 9 or claim 10, wherein
one or more circumferential ribs are provided to extend around the
rim of the lid.
12. A fluid container as claimed in any preceding claim, further
comprising a plunger affixed to the base and upstanding therefrom,
the plunger being in, or near, contact with the lid such that
depression of the base adjacent the plunger causes the plunger to
push the lid out of its tightly closed position.
13. A fluid container as claimed in claim 12, wherein the plunger
is arranged substantially centrally of the base.
14. A fluid container as claimed in claim 12 or claim 13, wherein
the plunger is integrally formed with the base and is clipped or
otherwise engaged with the lid.
15. A fluid container as claimed in any of claims 12 to 14, wherein
the plunger is mounted on the base by way of a button formed in the
base.
16. A fluid container as claimed in claim 15, wherein the button is
molded integrally with the base.
17. A fluid container as claimed in claim 15 or claim 16, wherein
the button is defined by an annular groove and has a domed
shape.
18. A container for facilitating mixing of first and second
materials, said container comprising a receptacle for the second
material, and a closure for closing the receptacle and for
containing the first material, wherein the closure comprises a
fluid container as claimed in any preceding claim.
19. A container as claimed in claim 18, wherein the first and
second materials are chemically reactive.
20. A container as claimed in claim 18 or claim 19, wherein the
closure is arranged to clip onto the receptacle.
21. A container as claimed in any of claims 18 to 20, wherein the
receptacle is a can, and the closure is used in the top opening of
the can such that the base of the closure will define the top of
the can.
22. A container as claimed in any of claims 18 to 21, wherein both
the receptacle and its closure have a substantially circular
periphery, and wherein the peripheral rim of the closure is annular
and defines an annular groove receiving an edge of the
receptacle.
23. A self-heating or a self-cooling container having an external
cavity for containing material for the self-heating or self-cooling
process, the external cavity being closed by a closure which
comprises a fluid container as claimed in any of claims 1 to
17.
24. A self-heating or a self-cooling container having a tubular
peripheral wall, a top member closing one end of the peripheral
wall, and a base member closing the other end of the peripheral
wall, an internal cavity for the contents of the container being
defined within the peripheral wall, wherein the base member is
indented to define an external cavity which extends within the
peripheral wall but is separated from the internal cavity, said
container further comprising a closure for said external cavity,
said closure having a fluid container closed by a lid which extends
within and across said external cavity, and wherein said closure
further comprises means operable to push the lid out of its closed
position whereby contents of the fluid container are released into
said external cavity.
25. A fluid container for use as a closure substantially as
hereinbefore described with reference to the accompanying
drawings.
26. A container for facilitating mixing of first and second
materials substantially as hereinbefore described with reference to
the accompanying drawings.
27. A self-heating or a self-cooling container substantially as
hereinbefore described with reference to the accompanying drawings.
Description
[0001] The present invention relates to a fluid container for use
as a closure, and to a receptacle having the fluid container as a
closure, the receptacle and closure containing first and second
materials which are to be mixed for use.
[0002] There have been many proposals for self-heating or
self-cooling beverage containers. WO 96/29255, for example,
discloses a can having the same external dimensions and shape as
conventional beverage cans, but having an indented base to define
an external cavity in which means to cool or heat the contents of
the can are received.
[0003] Heating or cooling of the contents of the can can be
achieved by using two chemical reactants which are stable when
separated, but which produce an exothermic reaction or an
endothermic reaction when mixed. U.S. Pat. No. 5,626,022 shows just
one example, from many, of an insert for a self-heating or
self-cooling can which enables mixing of the reactants when
required. This construction, as is common, utilises a breakable or
pierceable barrier to separate the two reactants and spikes or
other piercing means to break the barrier when their reaction is
required to heat or cool the can.
[0004] Many examples of such inserts have been proposed, but none
of them have been found to be entirely satisfactory. The designs
are often overly complicated, or do not withstand normal transport
and handling, or are prone to failure. The manufacturing costs of
such devices, which normally have a number of components, are also
high.
[0005] The present invention sought to overcome the problems noted
with the existing inserts for self-cooling and self-heating
containers.
[0006] According to a first aspect of the present invention there
is provided a fluid container for use as a closure, the fluid
container comprising a base, a peripheral wall upstanding from the
base and defining a chamber for containing fluids, the free end of
the peripheral wall defining an opening of the chamber, and a lid
received within said opening to tightly close said chamber, and the
fluid container further comprising means operable by pressing the
base to push the lid out of its tightly closed position to enable
exit of fluid from the chamber.
[0007] Although the fluid container was developed specifically for
use with self-cooling or self-heating beverage containers, it is
utilisable as a closure for a receptacle for a first material which
it is required to mix with a second material contained in the fluid
container. The first and second materials, which are to be mixed at
the point of use, may be chemically reactive.
[0008] A closure of the invention will find wide applicability as
it is simple to manufacture, and is robust, and is generally fail
proof. What is more, the simple action of pressing the base enables
the contents of the fluid container to be mixed with the contents
of a receptacle closed by the closure.
[0009] For example, hair dyes and hair perming agents are required
to be rendered active at the point of their application to hair.
This is done by reacting a first chemical with the rest of the
formulation. The first chemical may be housed in a fluid container
of the invention, and that fluid container used to close a tube or
bottle containing the rest of the formulation. The base of the
closure is pressed when it is required to use the hair dye or hair
perming agent to enable mixing of the first chemical from the fluid
container with the rest of the formulation.
[0010] In a totally different sphere, using a closure of the
invention in conjunction with a paint can, for example, will enable
paint of one color, contained in the fluid container, to be mixed
with paint of another color kept in the paint can. By this means,
for example, a fluid container of the invention would allow a paint
comprising a selected mix of two colors to be made available.
[0011] A fluid container of the invention is primarily suitable to
contain fluids, but may be utilised in any situation where the
mixing of a fluid material with other materials, and/or a chemical
reaction is required at the point of use.
[0012] In a preferred embodiment, the closure is intended for use
with a self-cooling or self-heating beverage container. In this
embodiment, the fluid container contains a first chemical reactant,
and the second chemical reactant is received within a receptacle
formed by an external cavity of the beverage container, for
example, as described in the aforementioned International
publication No. WO 96/29255 The fluid container of an embodiment of
the invention forms the closure of this external cavity.
[0013] Preferably, a closure of an embodiment of the invention is
arranged to clip onto the base of the beverage container such that
it acts to close its external cavity. Alternatively, the closure
may be mechanically connected to the container by other means, for
example, by a screw connection.
[0014] Preferably, the base of the fluid container is provided with
a peripheral rim, and said upstanding peripheral wall is arranged
on the base inwardly of the peripheral rim.
[0015] The peripheral rim may be appropriately shaped, for example,
to clip onto the base of the beverage container.
[0016] Although a fluid container of the invention may be of any
required peripheral shape, in a preferred embodiment the fluid
container is circular. In this case, the peripheral rim is annular.
An annular groove may be defined in the base, radially inwardly of
the peripheral rim, and arranged to receive a base edge of the
beverage container.
[0017] In an embodiment of a circular fluid container of the
invention, the peripheral wall is arranged radially inwardly of the
peripheral rim and defines a substantially cylindrical, fluid
containing chamber. The opening of the chamber defined by the free
end of said wall is substantially circular.
[0018] For efficient operation, the lid of the fluid container must
close the fluid containing chamber tightly enough to prevent
leakage of fluid during transport and/or handling either of the
fluid container separately or of the container when used as a
closure for other receptacles and containers.
[0019] For many applications it has been found that the provision
of a lid which snap fits into the chamber opening is
sufficient.
[0020] In a preferred embodiment of the fluid container, which is
particularly applicable where a liquid such as water is to be
contained within the chamber, the periphery of the lid is formed
with an upstanding rim arranged to engage within the opening of the
chamber.
[0021] Preferably, the inner surface of the lid and its peripheral
rim are shaped such that any increase in the pressure of the fluid
within the chamber tends to urge the rim into closer contact with
the opening of the chamber.
[0022] Additionally and/or alternatively, one or more
circumferential ribs are provided to extend around the rim of the
lid.
[0023] It has been found that such circumferential ribs are
effective to prevent leakage of liquid from the chamber, for
example, by capillary action.
[0024] Other means to hold the lid in its tightly closed condition
may additionally and/or alternatively be provided. For example, the
lid may be hingedly connected to the opening of the chamber. It is
also possible to fix or clip part of the lid to a structure
upstanding from the base of the fluid container. In a preferred
embodiment, this structure comprises a plunger forming said means
to push the lid out of its tightly closed position.
[0025] In a preferred embodiment, a fluid container of the
invention is used as the closure for an external cavity opening in
the base of a beverage container. In that situation, gravity can
assist in keeping the integrity of the container before
self-heating or self-cooling thereof is required, and gravity can
also be used to facilitate the self-heating or self-cooling
operation.
[0026] Thus, for a self-heating container where water is housed in
a fluid container of the invention, and lime is housed within the
external cavity of the beverage container the weight of the lime
tends to act, in normal circumstances, on the lid of the fluid
container in a direction to keep the chamber closed.
[0027] When it is required to self-heat the beverage container, it
is inverted to provide access to the base of the closure which is
then pressed to push the lid of the fluid container out of its
tightly closed position to release the water and begin the chemical
reaction. In this case, it is generally only necessary to move the
lid sufficiently to form a gap for the water contained within the
container to discharge. Once a flow of water is established, its
weight and gravity will act to open the lid more fully.
[0028] Although gravity will assist in the opening process, such
that initial full opening of the lid is not necessary, it is
preferred for said means to push the lid to be capable of opening
the lid by an appreciable amount.
[0029] In a preferred embodiment, a plunger affixed to the base and
upstanding therefrom is in contact with the lid such that
depression of the base adjacent the plunger causes the plunger to
push the lid out of its tightly closed position.
[0030] Preferably, the plunger is arranged substantially centrally
of the base.
[0031] The plunger may be affixed to the base alone or to both the
base and the lid. In a preferred embodiment, the plunger is
integrally formed with the base and is clipped or otherwise engaged
with the lid.
[0032] In a preferred embodiment, the plunger is mounted on the
base by way of a button formed in the base. This button may be a
separate structure provided in the base. Preferably, however, the
button is molded integrally with the base.
[0033] In a preferred embodiment, the button is defined by an
annular groove and has a domed shape. Normally, the dome is convex,
but pressure thereon causes a over-center movement reversing the
curvature of the dome. This pushes the plunger carried thereby
towards the lid and is very effective in pushing the lid out of its
tightly closed position.
[0034] The present invention also extends to a container for
facilitating mixing of first and second materials, said container
comprising a receptacle for the second material, and a closure for
closing the receptacle and for containing the first material,
wherein the closure comprises a fluid container as defined
above.
[0035] The first and second materials may be chemically
reactive.
[0036] In one implementation, the closure is arranged to clip onto
the receptacle. Alternatively, the closure may be arranged to be
mechanically connected to the receptacle, for example, by a screw
connection.
[0037] If the receptacle is a simple can or similar container, the
closure will be s used in its top opening such that the base of the
closure will define the top of the can.
[0038] Preferably, the base of the fluid container is provided with
a peripheral rim, and said upstanding peripheral wall is arranged
on the base inwardly of the peripheral rim.
[0039] The peripheral rim may be appropriately shaped, for example,
to clip onto the receptacle.
[0040] Although the receptacle may be of any required peripheral
shape, in a preferred embodiment both the receptacle and its
closure have a substantially circular periphery. In this case, the
peripheral rim is annular and may define an annular groove
receiving an edge of the receptacle.
[0041] In an embodiment where the receptacle is circular, the
peripheral wall of the closure is arranged radially inwardly of the
peripheral rim and is arranged to define a substantially
cylindrical, fluid containing chamber. The opening of the chamber
is also substantially circular.
[0042] According to a further aspect of the present invention there
is provided a self-heating or a self-cooling container having an
external cavity for containing material for the self-heating or
self-cooling process, the external cavity being closed by a closure
which comprises a fluid container as defined above.
[0043] The present invention extends to a self-heating or a
self-cooling container having a tubular peripheral wall, a top
member closing one end of the peripheral wall, and a base member
closing the other end of the peripheral wall, an internal cavity
for the contents of the container being defined within the
peripheral wall, wherein the base member is indented to define an
external cavity which extends within the peripheral wall but is
separated from the internal cavity, said container further
comprising a closure for said external cavity, said closure having
a fluid container closed by a lid which extends within and across
said external cavity, and wherein said closure further comprises
means operable to push the lid out of its closed position whereby
contents of the fluid container are released into said external
cavity.
[0044] Embodiments of the present invention will hereinafter be
described, by way of example, with reference to the accompanying
drawings, in which:
[0045] FIG. 1 shows, partly in section, a self-heating or a
self-cooling beverage container illustrating an external reactant
cavity thereof and a closure for the cavity,
[0046] FIG. 2 shows a larger view of the closure in its closed
position,
[0047] FIG. 3 shows the closure of FIG. 2 after opening thereof,
and
[0048] FIG. 4 shows an alternative embodiment of the closure.
[0049] The invention will be described hereinafter with reference
to a self-heating or a self-cooling beverage container. However,
the closure of the invention, which is described below, finds
general application wherever it is required to package first and
second materials such that they are separated initially but are
then mixed at the point of use. Generally, the first and second
materials will be chemically reactive.
[0050] The beverage container shown in FIG. 1 may be a metal or
plastics material beverage container 10 having a substantially
cylindrical peripheral wall 12 which is closed at one end by a top
member 14. As described in WO 25 96129255, a base member 16 of the
container is indented to define an elongate external cavity 20
which extends within the peripheral wall 12. It will be appreciated
that the peripheral wall 12 and the top and base members 14 and 16
of the container together define an internal cavity 22 in which the
beverage is received. It will be seen that the external cavity 20
extends within this internal cavity 22, but is separated therefrom
by the wall of the base member 16.
[0051] The container 10 illustrated in FIG. 1 is configured to have
the same external dimensions and shape as a conventional beverage
can. This means that the can can be filled and treated on existing
filling lines.
[0052] The external cavity 20 of the can 10 is to be utilised to
contain a first reactant material. Where the can is a self-heating
can, for example, the cavity 20 will be filled with quicklime
(calcium oxide). The cavity 20, incorporating the quicklime, is
closed by a closure of the invention generally referenced 30. For
the self-heating can, for example, this closure 30 will contain
water.
[0053] When it is required to heat the contents of the can 10, the
can is inverted and stood on its top member 14 so that the base of
the closure 30 is accessible. A button, described below, on the
bottom of the base is depressed whereby a water chamber 42 within
the closure 30 is opened so that water from the closure 30 flows
over the quicklime in the reactant cavity 20 to cause the
exothermic reaction. The steam which is generated is allowed to
vent around the periphery of the closure 30 through vents or
recesses (not illustrated) formed in either the periphery of the
closure 30 or in the wall of the cavity 20 or in both. The user
will retain the can in its inverted position until the exit of
steam has been completed. At this stage the contents of the can
will have been heated to a satisfactory temperature.
[0054] FIG. 2 shows the closure 30. In the embodiment illustrated,
the closure is molded from plastics material and comprises a base
member generally indicated as 32 and a lid generally indicated as
34. The base member 32 comprises a substantially circular base
having an annular peripheral rim 36. This rim defines an annular
recess 38 which enables the closure 30 to be clipped onto the base
of the can 10. Radially inwardly of the peripheral rim 36 is an
upstanding peripheral wall 40 which defines a generally cylindrical
chamber 42 for containing the water. The free end of the wall 40
defines a circular opening of the chamber 42 in which the lid 34 is
received. At its center, the base 32 has an upstanding plunger 44.
In the embodiment illustrated, this plunger 44 has an open top end
for receiving a fixing 46 of the lid 34.
[0055] The plunger 44 is affixed to the base centrally of a button
50 defined within the base 32 by an annular groove 48. It will be
seen that in the condition shown in FIG. 2, the button 50 is convex
and is radially inwardly of the annular groove 48.
[0056] The fixing 46 of the lid 34 comprises downwardly extending
projections 46 which are clipped into the top of the plunger 44
after the chamber 42 has been filled with water. It will be seen
that the lid 34 also has an upstanding rim 56 (FIG. 3) which, when
the lid 34 is snap fitted into position, is received within the
opening defined by the upstanding wall 40. The lid 34 is also
shaped radially inwardly of the rim 56 in a manner such that any
pressure generated within the chamber 42 tends to force the rim 56
into tighter contact with the internal surface of the opening of
the chamber 42. If required circumferentially extending ribs (not
illustrated) may be formed on the exterior of the rim 56, such that
they thereby come into contact with the internal surface of the
opening of the chamber 42. It has been found that such
circumferential ribs prevent capillary action, and hence leaking of
water from the chamber 42.
[0057] It has been found that where the lid 34 is a good snap fit
within the opening of the chamber 42, leakage of water from the
closure during normal transport and handling does not occur. Thus,
when a closure as 30 is clipped onto a can 10 as shown in FIG. 1 it
acts to keep the quicklime within the cavity 20 and to retain the
water in the chamber 42 but reliably separated from the
quicklime.
[0058] When self-heating of the can 10 is required it is inverted
as described above. The button 50 is pressed. The button 50 is
arranged to have an overcenter action such that, as indicated in
FIG. 3, on depression, the button moves from its initial convex
domed position to a substantially concave domed position.
Preferably, the button is stable in both of its states. This
movement of the button 50 moves the plunger 44 in a direction to
push the lid 34 out of the opening of the chamber 42. Generally, it
is expected that depression of the button 50 will cause a positive
opening of the lid 34 of the chamber 42 whereby water is quickly
released into the quicklime of the cavity 20 to commence the
self-heating reaction. However, because the container 10 is
inverted, it does not matter if positive and full opening of the
lid does not occur. In this respect, as long as there is some
opening of the lid, flow of the water from the chamber 42 will
begin and this will, in itself, tend to ensure fuller opening of
the lid.
[0059] It is not necessary for the lid 34 to be fixed at its center
to the plunger 44 although this does make a particularly secure and
robust construction. Thus, the plunger may simply abut the lid in
the closed position of FIG. 2.
[0060] The contents of the chamber 42 are, if the lid 34 is held
captive to the plunger 44 as in the illustrated embodiment,
confined to run out from the chamber 42 around the periphery of the
lid 34. This makes the illustrated container suitable for use only
with materials which flow, for example liquids, powders and other
fluids.
[0061] The self-heating container described and illustrated can be
filled on conventional filling lines, and the contents thereof may
be subjected to any treatments required. Thereafter, it is a simple
matter to invert each completed and filled container, fill its
external cavity with an appropriate charge of quicklime, and then
clip on a closure which is already filled with water. Generally, it
is preferred to simply clip the closure 30 onto the container 10,
but it would be possible to adhere or seal it into position if
preferred.
[0062] When the closure 30 is subsequently opened to commence the
reaction to heat the container, it is possible for water to be
pushed out of the cavity 20 towards the rim 36 of the closure.
Whilst it is required to have a pathway to vent air and steam, it
is not generally required for any water to leak out, even at this
stage. Accordingly, a wick, gasket or washer, or semi-permeable
membrane (not shown) may be housed in the annular recess 38 or
sited around the wall 40 of the closure 30. Additionally and/or
alternatively, the closure 30 may be a tight fit on the container,
and micro grooves (not shown) may be in the annular recess 38
and/or around the wall 40. If the micro grooves are of the order of
6 thou to 10 thou (thousandths of an inch) they will allow air and
steam to vent, but not allow the escape of water.
[0063] FIG. 4 shows an alternative embodiment of the closure 30. In
the embodiment illustrated in FIG. 4 features of the closure which
are the same or similar to features of the closure shown in FIGS. 2
and 3 have been accorded the same reference numerals.
[0064] The closure 30 of FIG. 4 is arranged to vent air and steam
through the center thereof. This may be as an alternative to, or
additional to, the peripheral venting described above. Thus, in the
embodiment of FIG. 4, a vent 60 extends through the fixing 46 of
the lid 34. The plunger 44 is hollow and thereby defines an air and
steam passageway from the external cavity 20 to the exterior of the
can 10 Preferably, the passageway contains filter material 62 to
prevent egress of water whilst allowing air and steam to exit. The
filter material 62 will also act to prevent ingress of water and
other contaminants from atmosphere into the external cavity 20.
[0065] It will be appreciated that venting of air and steam will
generally be required upon depression of the button 50 because of
the consequent reduction in volume within the closure 30.
Thereafter, venting becomes necessary as a result of the chemical
reaction during which air is heated and thereby expanded. Normally
heating as a result of the reaction continues after air and steam
has been vented.
[0066] It is preferred that the closure be made of a plastics
material. Presently it is preferred that the plastics material be
opaque so that the water within the closure 30 is not visible.
[0067] It is proposed that external surfaces of the closure and/or
of the container 10 be made of, or coated with, materials having
thermochromic properties. In this way, if the closure has been
operated to cause self-heating of the can at any time, this is
immediately apparent by, for example, a change in the color of part
of the closure and/or of part of the container 10.
[0068] In one embodiment, the lid 34 of the closure 30 is made of a
plastics material with a melting point which is sufficiently low
that it is melted by the heat of the exothermic reaction of the
water and the quicklime. By this means the hydrating/expanding lime
may be readily accommodated within the thereby expanded external
cavity 20.
[0069] It will be appreciated that modifications to or variations
of the embodiments described and illustrated may be made within the
scope of this application.
* * * * *