WO2003062720A2

WO2003062720A2 - Apparatus for varying the temperature of a container for food or drinks

Info

Publication number: WO2003062720A2
Application number: PCT/GB2003/000153
Authority: WO
Inventors: Jung Quy Doe
Original assignee: Jung Quy Doe
Priority date: 2002-01-17
Filing date: 2003-01-14
Publication date: 2003-07-31
Also published as: GB2400305A; AU2003202663A1; WO2003062720A3; GB0415918D0

Abstract

Apparatus for varying the temperature of a container (16) for food or drinks is described which comprises a holder (14) for the container (16), an electrical heater or cooler (34), and a switch (36), in which engagement of the container (16) with the holder (14) activates the switch (36). The apparatus may also include a base unit (12) which connects to the holder (14). The apparatus is preferably operated by an external power source, in combination with an internal battery (25).

Description

Title: Apparatus for Varying the Temperature of a Container for Food or

Drinks.

Description of Invention This invention relates to apparatus for varying the temperature of a container which contains food or drink. In particular, although not exclusively, this invention relates to consumer appliances for the heating of small drinks containers.

A wide variety of food and drinks is readily available in such containers, which typically are cans. Many are intended to be consumed hot, however the cans are usually bought at room temperature and thus need to be heated before consumption. Even if the cans are preheated there is often a need to keep them warm whilst the contents are consumed. Electrically powered devices such as kettles or cooker plates are often used for this. For car drivers, a small heating element can be used, usually powered at 12 volts from the cigarette lighter socket; this is typically inserted into a cup of water to boil it for making tea or coffee. For hikers, small portable heaters such as primus stoves or bottled gas powered devices can be used.

All these devices have their limitations. Fuel powered devices produce flame, and their utility and convenience is therefore very limited. Electrically powered devices are more convenient, but all of these devices are generally limited to heating open cups of liquid.

Some small electric can heaters have been devised, but have not been successful due to difficulties in controlling the devices, the slow speed of heating and the requirement to accept a variety of cans in the device whilst still supporting the can adequately within the device.

Recently self-heating cans of coffee have been introduced commercially, but these are relatively expensive and use an inconvenient chemical heating method which makes the cans expensive and inconvenient to dispose of. Furthermore, the liquid in these cans is generally only heated until it is warm, rather than hot, which is undesirable.

There is, therefore, a need to provide a more flexible and convenient need for heating food, particularly liquid. According to a first aspect of this invention there is provided apparatus for varying the temperature of a food or drinks container comprising a holder for the container, an electric heating element, and a switch, in which activation of the switch is consequential on engagement of the container with the holder. Preferably the electric heating element operates via induction. Alternatively the electric heating element may comprise a resistance heating element and the can may be predominantly heated by conduction.

Preferably the engagement provides a mechanical interlock, and this may, for example, be provided by a bayonet fitting between the holder and the container. This invention combines control of the heater or cooler with securement of the container with the holder thereby ensuring that the device is not activated before the container is secured. It thus provides a safer way to heat virtually any container of food or drink.

The invention is preferably installed for use in an automated vehicle. The holder may comprise engagement formations which provide a slot with which the container may engage. Conveniently the engagement formations comprise two slots arranged in a generally "V" shape. A first slot may extend downwardly from the upper rim of the holder and is conveniently longer than the second slot. The switch may be pressure activated and engagement between the container and the holder may provide sufficient pressure to activate the switch. Thus, when the engagement formations comprise two slots arranged in a V, the container, having formations which engage with these slots, may be pressed downwards in the holder as the engagement formations are pushed through the first slot which activates the switch. The formations are then pushed into the second slot and cannot passively return, maintaining the pressure on the switch.

The apparatus may further comprise a base unit which may be removably connected to the holder in such a manner that it may be easily removed. The base unit may provide a supply of electricity to the holder.

Preferably the base unit is connected to the holder by a kettle-type connection.

Since the holder may be easily connected and disconnected from the base unit, the user may handle the container through the holder, for example picking up the holder to drink from the container, rather than having to remove the container from the holder. Thus the user can use the container safely even though it may be hot.

Preferably in such apparatus the heating element and the switch are carried by the holder. When the holder is secured to the container this ensures intimate contact between the holder and the container.

The base unit preferably comprises an adapter and a plug.

The holder may provide an insulating cover for the container, and so conveniently the holder is made of a plastics material. This ensures that the user may handle the container, using the holder, even when it is hot. This apparatus is particularly useful for heating a drink container.

According to this invention there is also provided a container for use with apparatus as described above. The container may comprise projecting formations which may engage the holder of the above apparatus.

The container preferably comprises an enclosure for food or drink and a sleeve, the sleeve conveniently providing the engagement between the container and the holder.

The enclosure may be made of a thermally conductive material, such as a metal material, whilst the sleeve may be made of a thermally insulating material, such as a plastics material. Thus, in use, the enclosure may contact the electrical heating element and conduct heat to the contents of the container whilst the user may handle the container safely using the sleeve.

The sleeve may be removably connected to the enclosure, for example being snapped to an upper portion of the enclosure. This enables one sleeve to be used for many different enclosures. Alternatively, the sleeve could be integral with the container and sold as part of the enclosure.

A sleeve for use in such a container is also provided by this invention.

According to a second aspect of this invention there is provided a power module for an electrical domestic appliance comprising a connector, adapted to connect to an external power source, a battery, and an output connector characterised in that the output may be provided with power drawn from the battery and the external power source simultaneously.

This enables a substantial increase in power to be provided to the consumer appliance. Preferably the external power source is a domestic mains, alternatively the consumer appliance could be adapted for use in a vehicle in which case the external power source could be the twelve volt battery of the vehicle.

Preferably the battery is rechargeable and the power module further comprises an adapter which, when the input connector is connected to the external power source may trickle charge the battery.

Such a power module is particularly suitable for use with apparatus for varying the temperature of a food or drinks container according to the first aspect of this invention, but the power module is also suitable for use with any other domestic appliance, and this invention extends to a domestic appliance powered by such a module.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings in which;

Figure 1 shows schematically an exploded section view through a first embodiment of a can heater; Figure 2 shows schematically a perspective view of the can heater of Figure 1, with a container in place in the holder;

Figure 3 shows schematically a perspective view of a container suitable for use in the can heater of Figure 1; Figure 4a shows schematically a top view of the embodiment of Figure

1, showing the pressure relief tab in more detail:

Figure 4b shows schematically a section view through the can, again giving detail of the pressure relief tab.

Figure 5 shows schematically a section view of a third embodiment of a can heater;

Figure 6 shows schematically a section view of a fourth embodiment of a can heater;

Figure 7 shows schematically a section view of a fifth embodiment of a can heater; and Figure 8 shows schematically a sixth embodiment of a can heater, which operates by induction.

The first embodiment of the can heater shown in Figures 1 to 3 and indicated generally at 10 comprises a base unit 12, a holder 14 and a container 16. The holder 14 may be removably connected to the base unit 12 via the kettle type plug 18 and socket 20 arranged on the base unit 12 and the holder 14 respectively. The holder may also be removably connected to the container 16 via a bayonet-type connection provided between projecting formations 22 provided on the container 16 and slots 24 provided on the holder 14.

The components of the system will now be described in more detail. The base unit 12 comprises a rechargeable battery 25, a plug 26, a controller 27, an adapter 28 and a mains plug 29. The base unit 12 is connected via a cable to a plug 26, which is adapted to fit the 12 volt cigarette lighter slot of a car. This provides a connection with an external electrical supply. The base unit 12 also comprises an adapter 28, which is connected via a cable to mains plug 29. The adapter transforms the mains voltage to a lower, conventially D.C. voltage.

The controller 27 may draw electricity from the rechargeable battery 25, the mains plug 29, or the car plug 26, and supplies electricity to the kettle- type plug 18.

The holder 14 comprises a hollow open top cylinder having a solid lower surface 36 into which is built the kettle type socket 20. An annular wall 32 extends generally vertically from the lower surface 30. These outer walls of the holder 14 are made of a plastics materials such as polypropylene. An electrical heating element 34 lines the annular walls 32 and the base 30 and is connected to a pressure sensitive switch 36. The pressure sensitive switch 36 comprises two contacts 38 separated by a resilient leaf spring 40. Each of the contacts of the switch 36 are connected to the kettle type socket 20. The switch is arranged so that when the contacts are bought together the heating element 34 is turned on.

The holder 16 also comprises engaging formations 24. These consist of two slots 54, 56 in the annular wall of the holder 14. The slots 54, 56 are arranged in a generally V-shape. The first slot 54 extends at an angle of around 45° generally downwardly of the upper rim of the annular wall 32. It is significantly longer, being about twice as long, as the second slot 56, which extends generally upwardly at an angle of around 45° from its junction with the first slot 54.

The container 16 comprises an enclosure 40 and a sleeve 42. The enclosure 40 is made of a metal material, such as aluminium and is usually sealed, in this case being a typical drinks can, containing a coffee drink. The container may be opened by operating a ring pull 44. The sleeve 42 is made of a thermally insulating material, for example a plastics material such as polypropylene. The sleeve 42 is generally in the form of a hollow cylinder, having an annular wall 46, and an upper rim 48 which extends over the top of the enclosure. The sleeve surrounds the upper portion of the enclosure 40, the top surface of the enclosure 40 abutting the upper rim 48 of the sleeve 42. To use the can heater the enclosure 40 is first connected to the sleeve 42, being slid into the sleeve 42. The sleeve 42 being slightly resilient snaps onto the enclosure 40. Alternatively the enclosure 40 and sleeve 42 may be manufactured in one piece or the sleeve 42 may be sealed to the enclosure during manufacture. The container 16 is then inserted into the holder 14. The projecting formations 22 on the sleeve 42 must be aligned with the slots 24 in the holder 14. The user then presses and twists the container 16 relative to the holder 14 so that the projecting formations or lugs 22 slide through the first slot 52 of the complementary formations 24. As the container 16 is pressed down into the holder 14 the contacts 38 close and the pressure switch 36 is activated.

Once the projecting formations are passed the apex of the V shape formations 24 the user may release the container 16 which will be pushed upward and rotated slightly by the action of the spring 40, the motion of the container being constrained by the movement of the projecting formations 22 in the second slot 54. Although the container does move slightly upwardly the contacts 38 remain engaged and the heater remains on.

It will of course be appreciated that the lugs 22 and the slots 52, 57 may be reversed

The holder is, of course, connected to the base unit via the kettle-type connection 18, 20. The holder is supplied with electricity by the rechargeable battery 25 and either the mains plug 29 or the car plug 26. The controller may adjust the amount of electricity from each source depending upon the level of charge in the battery. In general, however, a substantial amount of power is drawn from both the internal and the external source being about 60% from the battery and 40% from the plug and this allows the can to be heated in a relatively short period of time.

When the heater is actuated the coil 34 heats up and makes good thermal contact with the metal material of the enclosure 40. The heater is controlled by a thermostat 56, which is connected to temperature sensor 58, and prevents the can from overheating. Alternatively a timer arrangement could be used.

When using a can heater which is powered from the cigarette lighter socket of a car, and a rechargeable battery, the heating operation may take in the region of 5 minutes. Without the rechargeable battery the heating operation may take in the region of eight minutes.

When the heating operation is complete the user may release the container from the holder, open the enclosure, and drink from the container. The user's lips are protected from the hot metal of the container 40 by the insulating plastic material of the sleeve 42.

Alternatively the user may simply detach the holder 14 from the base unit 12 and, opening the enclosure via a ring pull 44, drink from the container via the holder 14. This has the additional advantage that the users hands are protected throughout drinking. Once the user has finished drinking they may dispose of the can and the integral sleeve 48. The holder, on the other hand, is replaced on the base unit ready for the next heating operation. The system is shown as a self contained unit but it may alternatively be built into a car.

It is, of course, not necessary to use a pressure sensitive switch, one alternative would be to use the conductive material of the container itself as a switch to complete the circuit.

A second embodiment of a can heater is shown in Figure 4, this can heater is similar to that shown in Figure 1 but has a plastic pressure release strip or tab 50 as an integral part of the sleeve 48. The tab 50 has a serrated connection with the sleeve 48 and is positioned underneath the ring pull 44.

Additionally, the holder 14 has a projection 52 positioned at the upper, engagement, end just above the heating element 34, as best seen in Figure 4b. When the sleeve 48 is engaged with the holder the projection 52 engages with the plastic tab 50, forcing it upwards. The force is sufficient to break the serrated connection between the tab 50 and the sleeve 48, so that the tab 50 does actually move upwardly and thus, in turn, raises the ring pull 44.

This causes the can to be opened slightly and means that any pressure build up in the can during the heating will not represent a problem.

Alternatively, the tab could be an additional component of the apparatus and inserted between the sleeve and can and the ring pull during assembly.

A further embodiment is shown in Figure 5. This figure shows a can heater comprising a base unit 60, a holder 62 and a container 64. The base unit 60 has a cable 66 coupling it to a plug 68 which will fit into a standard car cigarette lighter. The base unit may also have a further cable 70 coupling it to a standard mains plug 72 with a built in mains to 12 volts transformer. Alternatively, the transformer may be separate or built into the base unit 60.

The base unit 60 carries a heater element 74 mounted on a pressure sensitive contact switch 76. The holder 62, which is integral with the base unit 60 comprises an annular wall 78 having a upper rim 80 of similar diameter to a standard can.

The base unit 60 includes a controller 82 including a timer which opens the circuit to the heater element 76 after a time calculated to raise the temperature of a standard size can to a suitable value for a hot drink. If desired, the timer can be provided with an adjustment control (not shown), enabling the set temperature to be adjusted as desired and/or the set time to be changed to match different sizes of cans. Alternatively, a temperature sensor can be used to prevent the can from being overheated. If this is done, then the sensor can be arranged to cause the heater to cycle to maintain the can hot if it is left in the system for a long period. The rim 78 may connect to the container 64 via a snap action or may be provided with a screw thread, bayonet connection, or the like.

The container 64 may be provided with an outer layer 84 of thermal insulation, corresponding screw threading or other engagement means may conveniently be formed in that layer. The heater element 76 is preferably generally circular. For general use, it is preferably flat, although it may be shaped to fit a can shape with a base which is not flat. For example, the can may be provided with a large dimple in which the heater element will fit. The heater element may be surfaced with a material which combines good thermal conductivity with sufficient resilience to allow it to mould itself to the shape of the bottom of the can, so that sufficient heating is obtained with cans which have slightly stepped or curved bases.

For heating cans which contain thick or viscous contents, it may be preferable for the heater element to be D shape (semi-circular) to promote better convection flow of the contents within the can. The base unit 60 includes a housing 86 into which the container may be placed, with a lid 88 which can be closed over the container. The lid 88 is hinged to the housing at one corner 90 and includes a snap engagement means 92 which may hold the lid closed. A spike 94 is located on the inside of the lid 88 which is designed to pierce the top of the container 64, to provide an escape route for steam and gas and so ensure that the user will not become scalded when they open the can after it has been heated. The spike 94 may carry a further contact means 96. Alternatively this contact means 96 may provide the mechanism for activating the heated unit. Alternatively or additionally the container 64 may be manufactured with a pressure relief valve in its top.

To use the can heater the container is placed inside the housing 86 in engagement with the holder 78 via its annular rim 79. As the container 64 is slid into the holder 78, and is thereby secured, it makes contact with the pressure sensitive switch 74 and activates the heater. Alternatively activation of the heater may be delayed until the lid 92 has been closed.

In an alternative arrangement (not shown) the container may have a deep recess, for example a slightly tapered tube along the axis of the container with the heater element being a projecting device which fits into the recess. The heater element may be arranged to retract into the base unit when the container is removed from the system. This arrangement allows the entire accessible surface of the container to be insulated, so that the user cannot burn their hand by touching the bottom of the container. Of course, the container itself may be made partially of plastics material.

It may then include a metal insert having a ring pull which may be used for heat transfer. Alternatively the container wall might have a thin portion for heat transfer, the remaining being thicker for insulation.

The base unit includes an indicator, LCD panel 98 which carries various messages such as "power on", "heating can" and "ready" via indicator lights 100, 102, 104, which indicates the above states with letters "P", "H", and "R". The P light is on whenever the system is plugged in; the H light comes on when the can is inserted into the system and the R light comes on when the desired temperature is reached (or the timer times out). The H and R light go out when the can is removed from the system.

Figure 5 shows a fourth embodiment, which comprises a base unit 110 and a holder 112. The holder 112 carries a heater element 114 mounted on a weight sensitive contact switch 116. It also carries a plug 118 which may connect to a corresponding socket 120 arranged on the base unit 110.

With this embodiment a container 122 of conventional form can be slid into holder 112 which forms a tight fit on the container. Projecting formations

124 on the container and corresponding formations 126 on the holder provide engagement between the holder and the container as the weight sensitive switch is activated.

The circuit may be completed by plugging the holder 112 into the socket 110.

Figure 6 shows a fifth embodiment. The fifth embodiment comprises a base unit 128 and a holder 130. A container 132 is also shown having an integral heating element 134, thermally insulated walls 136, and a plug arrangement 138. The base unit 128 has a corresponding socket 140. The container 132 may be slid into the holder 130 and engage therewith.

As the engagement is made the socket 140 and plug 138 connect which activates the system.

This embodiment requires a relatively expensive container since the container, which is not reusable, includes the heating element. However it is very safe as the heating element is concealed and protected in the container.

Figure 8 shows a sixth embodiment of an electric can heater, 150, one in which the can is heated by induction rather than by an electrical resistance element.

The holder 152 shown in Figure 8 is similar to that shown in the embodiment of Figure 1 but, instead of a resistive heating element, the holder comprises an inductive heating element 154 comprising a coil 156. The holder also comprises a dome shaped heating element 158.

The base is similar to that of the embodiment of Figure 1 but instead of adapting the alternating mains current to direct current, the direct current from the rechargeable battery and/or the car plug is adapted to be alternating current. A relatively high frequency alternating current is used and the can is situated as close as possible to the coil 156, in order to increase the heating effect.

When the can heater is activated the magnetic field (shown in Figure 8) is generated within the holder and this, in turn, causes a heating effect in the metal surface of the can, and in the dome shaped heating element 158. In turn, the liquid in the can is heated by conduction. The heating is controlled by a thermostat comprising a sensor 160 and a controller in the base (not shown).

Naturally alternative arrangements will occur to the skilled person on reading this specification which are also encompassed by the invention. For example, the apparatus could be adapted for use in cooling, rather than heating, a container.

In the present specification "comprises" means "includes or consists of and "comprising" means "including or consisting of. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. Apparatus for varying the temperature of a container for food or drinks comprising a holder for the container, an electrical heating element, and a switch, in which activation of the switch is consequential on engagement of the container with the holder.

2. Apparatus for varying the temperature of a container for food or drinks according to Claim 1 in which the electrical heating element comprises a resistance heating or cooling element.

3. Apparatus for varying the temperature of a container for foods or drinks according to Claim 1 in which the electrical heating element comprises an induction coil.

4. Apparatus for varying the temperature of a container for foods or drinks according to any preceding claim in which the engagement provides a mechanical interlock.

5. Apparatus for varying the temperature of a container for food or drinks according to Claim 4 in which a bayonet fitting provides the mechanical interlock.

6. Apparatus for varying the temperature of a container for food or drinks according to Claim 4 or Claim 5 in which the holder comprises engagement formations providing a slot with which the container may engage.

7. Apparatus for varying the temperature of a container for food or drinks according to any preceding claim further comprising a base unit which may be removeably connected to the holder, and which may provide a supply of electricity thereto.

8. Apparatus for varying the temperature of a container for food or drinks according to any preceding claim in which the holder provides an insulating cover for the container.

9. Apparatus for heating a drinks container according to any preceding claim.

10. Apparatus according to any preceding claim for installation in an automated vehicle.

11. A container for use with apparatus according to any preceding claim.

12. A container according to Claim 11 comprising projecting formations which may engage the holder.

13. A container according to Claim 11 or Claim 12 comprising an enclosure for the food or drink and a sleeve, in which the sleeve provides the engagement between the container and the holder.

14. A container according to Claim 13 in which the enclosure is of a thermally conductive material and the sleeve is of a thermally insulating material.

15. A container according to any of claims 13 to 14 in which the sleeve is removeably connected to the enclosure.

16. A sleeve for use in a container according to any of claims 13 to 15.

17. A power module for an consumer appliance comprising an input connector, adapted to connect to an external power source, a battery, and an output connector characterised in that the output may be provided with power drawn from the battery and the external power source simultaneously.

18. A power module according to Claim 17 in which the external power source is mains power.

19. A power module according to Claim 17 in which the external power source is a vehicle battery.

20. A power module according to any of Claims 17 to 19 in which the battery is rechargeable and the power module is adapted to trickle charge the battery when the input connector is connected to an external power source.

21. An electrical domestic appliance, particularly apparatus for varying the temperature of a container for food and drink, comprising a power module according to any of claims 17 to 20.