The present invention relates to a self-heating or a self-cooling container.
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.
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, proposes the use of a module, which is pre-assembled and is then inserted into the can.
Many examples of such inserts and modules 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. Furthermore, the need to form the module as a sub-assembly adds to the manufacturing costs.
The present invention seeks to overcome the problems noted with the existing inserts for self-cooling and self-heating containers.
According to the present invention there is provided a self-heating or 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, and wherein means for heating or cooling the contents of the container are received within said external cavity, said heating or cooling means comprising a breakable membrane dividing the external cavity into first and second chambers, a first reactant material sealed within the first chamber by said breakable membrane, a closure member closing said second chamber to retain a second reactant material therein, and piercing means movable to break or pierce the breakable membrane whereby said first and second reactant materials can mix.
With an embodiment of a self-heating or a self-cooling container of the invention, there is no requirement to form the heating or cooling means into a sub-assembly. Instead, the individual components of the heating or cooling means are simply assembled within the external cavity of the container. This preferably occurs after the container has been filled, and its contents have been subjected to any required treatments.
When the reactant materials mix there will generally be a chemical reaction, for example, to produce a heating or a cooling effect. Such a chemical reaction may be associated with pressure changes, as well as temperature changes. Accordingly, pressure venting means are preferably associated with the closure member and/or with the container. In a preferred embodiment, a one way valve or seal is associated with the closure.
Although the container was developed specifically for use with self-cooling or self-heating beverage containers, it is adaptable for use as a container in which a first material which it is required to mix with a second material can be contained and subsequently mixed. The first and second materials, which are required to be mixed at the point of use, may be chemically reactive.
The present invention extends to a container for facilitating the mixing of first and second materials, the container comprising a cavity, a breakable membrane dividing the cavity into first and second chambers, a first material sealed within the first chamber by said breakable membrane, a closure member closing said second chamber to retain a second material therein, and piercing means movable to break or pierce the breakable membrane whereby said first and second materials can mix.
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 the second chamber of a container of the invention, and the first chamber in the cavity used to contain the rest of the formulation. The closure is pressed when it is required to use the hair dye or hair perming agent to enable mixing of the first chemical with the rest of the formulation.
In a totally different sphere, a container of the invention may constitute a paint can, for example, with paint of one colour, contained in the first chamber, to be mixed with paint of another colour kept in the second chamber. By this means, for example, a container of the invention would allow a paint comprising a selected mix of two colours to be made available.
A 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.
It would be possible, for example, for the closure member and the piercing means to be separate elements. For example, a piercing member could be arranged to be movable through and with respect to the closure member.
However, in a presently preferred embodiment, which is simple to construct and easy to use, the closure member supports the piercing means and enables movement of the piercing means to break or pierce the breakable membrane.
It would also be possible for the closure member to comprise a cap in which a compartment is defined which may receive the second reactant material and/or enclose further elements of the container.
However, it is presently preferred that the construction be as simple as possible.
In an embodiment, the closure member comprises a periphery arranged to engage the container, and carries at least one elongate piercing member which extends from the inner surface of the closure member.
The or each elongate piercing member may be fixed to the inner surface of the closure member or may be integrally formed therewith.
It is necessary for the piercing member(s) to be movable to pierce the breakable membrane. Such movement could be accommodated by mounting the piercing member(s) on a pushbutton or plunger construction supported within the closure member. Where the piercing member(s) are directly affixed to, or integrally formed with, the closure member, hinge means may be formed in the closure member.
In a presently preferred embodiment, the closure member and the piercing member(s) are formed from a plastics material, and the closure member is formed to provide the necessary movement for the piercing member(s).
In a preferred embodiment, an elongate piercing member is affixed to the closure member and upstanding therefrom, the arrangement being such that depression of the closure member adjacent the piercing member moves the member to pierce the breakable membrane.
Preferably, the piercing member is arranged substantially centrally of the closure member.
The piercing member may be affixed to the closure member. In a preferred embodiment, the elongate member is integrally formed with the closure member.
In a preferred embodiment, the piercing member is mounted on the closure member by way of a button formed in the closure member. This button may be a separate structure provided in the closure member. Preferably, however, the button is moulded integrally with the closure member.
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 overcentre movement reversing the curvature of the dome. This pushes the piercing member carried thereby towards the breakable membrane to pierce the breakable membrane.
Preferably, the closure member is arranged to clip onto the base of the container such that it acts to close its external cavity. Alternatively, the closure member may be mechanically connected to the container by other means, for example, by a screw connection.
For example, the closure member may be provided with a peripheral rim which is appropriately shaped to clip onto the base of the container.
Although the closure member may be of any required peripheral shape, in a preferred embodiment the closure member is circular, and, in this case, its peripheral rim is annular. An annular groove may be defined in the closure member, radially inwardly of the peripheral rim, and arranged to receive a base edge of the container.
Preferably, the closure member and its peripheral rim are shaped such that any increase in pressure within the second chamber of the external cavity tends to urge the rim into better engagement with the base edge of the container.
A container of the present invention was developed specifically for use as a self-cooling or self-heating container for beverages. Of course, it will be appreciated that the container may be used for any contents.
The reactant materials are chosen to give the reaction required and may be in any particular form. However, the structure of the cooling or heating means is particularly appropriate where the first reactant material sealed within the first chamber is in a powder, granular, or other particulate form, whilst the second reactant material in the second chamber is a fluid.
When it is required to cool or heat the container, it is inverted to provide access to the base of the closure member which is then pressed to cause the piercing member to pierce the breakable membrane. This releases the fluid in the second chamber such that it flows into the first chamber to begin the chemical reaction. The use of a second reactant material in fluid form assists in the mixing process.
For a self-heating container, for example, quicklime may be filled within the first chamber and water retained within the second chamber. Lime is extremely hydroscopic and it has been found that sealing the lime by the breakable membrane within the first chamber improves the shelf life of the container greatly as the lime is thereby sealed from contamination.
The breakable membrane may be of any material capable of sealing the first reactant material in the first chamber, and supporting the weight of that material when the container is in its normal upright position. For example, the breakable membrane may be formed by a disc of a metal foil secured to the external cavity to extend across it.
In a presently preferred embodiment, the external cavity is shaped to define an annular flange therein. A disc shaped breakable membrane may then be affixed to the annular flange after a charge of the first reactant material has been filled into the first chamber. For example, the disc shaped breakable membrane may be affixed to the annular flange by way of a carrier member. Alternatively, the periphery of the disc shaped breakable membrane may be affixed directly to the annular flange.