WO2006040540A1

WO2006040540A1 - Portable food warmer

Info

Publication number: WO2006040540A1
Application number: PCT/GB2005/003907
Authority: WO
Inventors: Stephen Compton; Donna Compton
Original assignee: Stephen Compton; Donna Compton
Priority date: 2004-10-11
Filing date: 2005-10-11
Publication date: 2006-04-20
Also published as: GB0422528D0; GB2418982A

Abstract

The present invention relates to apparatus (10) for warming food, and in particular to apparatus for warming food for babies and infants. The apparatus preferably comprises a base housing (12) including at least one rechargeable battery, electronic control circuitry, means for retaining the battery and providing electrical connections between the battery and the control circuitry, a flexible housing (14) depending from the base housing adapted to retain a food container to be warmed.; and a flexible heating element (16) contained within the housing and adapted to surround the food container in use, the heating element being connected to said control circuitry.

Description

Portable Food Warmer

The present invention relates to apparatus for warming food, and in particular to apparatus for warming food for babies and infants.

As is well known, milk (whether breast milk or formula milk) is fed to babies from a specially designed bottle with a suitable teat. Prior to feeding the child, the milk must be warmed. Similarly, for older infants, pre-prepared food is stored in jars or similar containers and most preferably requires to be warmed before presentation to the infant. Warming milk or food when in the home is not normally a problem as suitable facilities are available. Although not generally advised, a microwave oven can be used, or the container containing the milk or food can be placed in a pan or bowl of warm water. Specially designed bottle warmers are also widely available which comprise a water bath heated indirectly by an electrical element. The container of milk or food is placed in the water bath and is heated by the surrounding water.

Clearly, these methods of warming milk and food are not convenient when away from the home. A common solution is for the parent or carer of a child to carry a vacuum flask of hot water and a suitable bowl or container. The child's bottle or food jar is placed along with a quantity of the hot water. This method is slow and inconvenient especially as it requires extra equipment in the form of the flask and bowl to be carried. An alternative, but similar method is for a parent or carer to request a bowl and hot water from a restaurant or similar establishment. Of course, this requires that a suitable establishment is close at hand and may also obligate the carer to purchase food or drink for themselves. Also, many establishments seem reluctant to provide this facility, on the grounds of health and safety, fearing spillage of the hot water. Portable bottle warmers are known which rely on the release of latent heat of fusion of a suitable chemical. The chemical is contained in a flexible jacket which is intended to wrap around the bottle of milk or food container. Before use, the jacket containing the chemical is heated and then allowed to cool gradually. The chemical maintains it's liquid state until subjected to a sharp physical shock whereupon it solidifies, releasing the latent heat of fusion to heat the bottle or container. This is not effective, since it is inherent in travelling with a child that the jacket may be subject to physical shock, causing premature release of the heat. Also, this type of warmer is a single-use device, so that if the quantity of heat released is insufficient, or if more than one bottle or food jar is to be warmed, a plurality of warmers is required.

A further type of bottle warmer comprises a flexible metal element contained in a thin flexible plastics cover which is wound around the upright walls of the bottle or jar. The element is connected by way of an electrical lead and plug to the 12V outlet of a car (often the cigarette lighter). Although simple in construction, these devices tend to be inefficient and take too long to heat the bottle or jar contents. They are also restricted to use where a 12V supply is available.

Each of the prior art devices has its limitations and disadvantages and accordingly the present invention seeks to provide a bottle or food warmer which overcomes, or at least alleviates, these disadvantages. More particularly, the present invention seeks to provide a bottle or food warmer, especially for baby or infant food, which is truly portable and which is effective in heating food in an acceptably short time.

According to the present invention there is provided a warmer apparatus, in particular for baby or infant foodstuffs, comprising: (a) a base housing that includes at least one rechargeable battery, electronic control circuitry and means for retaining the battery and providing electrical connections between the battery and the control circuitry; (b) a flexible housing depending from the base housing adapted to retain a food container to be warmed; and (c) a flexible heating element contained within the housing and adapted to surround the food container in use, the heating element being connected to said control circuitry.

The warmer apparatus preferably comprises first connection means for optional connection of the control circuitry to a mains supply;

The warmer apparatus preferably comprises second connection means so that the control circuitry may be advantageously connected to a nominal 12V supply.

In a preferred embodiment, the flexible housing of the warmer apparatus comprises a natural or synthetic rubber or rubberised material. The flexible housing may also comprises a neoprene or neoprene-like material.

The flexible heating element is preferably arranged adjacent both the base and sides of the food container.

The flexible heating element may be a laminate heating element comprising an resistance heating element attached to at least a first web of plastic material. In a particular embodiment, the flexible heating element may also comprises an electrically conducting material that is etched to form a meandering path and arranged on a web of plastic material.

The flexible housing may advantageously comprise closure means so that the housing may be closed the housing after the insertion of a food container. The closure means preferably comprises a drawstring.

Preferably, the rechargeable battery comprises a plurality of cells that optionally provides a nominal HV- 12V in total. It is preferable for the cells to be nickel - metal hydride (Ni-MH) cells. Each cell preferably has a rated capacity of 155OmAh. The warmer apparatus may comprise a temperature sensor that is electrically connected to the control circuitry and operative to determine a temperature within the flexible housing. The temperature sensor preferably is, or preferably acts as, a thermostat, such that electrical power to the heating element is advantageously turned off when the temperature proximate the temperature sensor reaches a predetermined threshold value.

For a better understanding of the invention and to show how the same may be carried into effect reference will be made by way of example only to the following drawings, in which:

Figure 1 is a schematic cross-section through a warmer apparatus according to the invention;

Figure 2 shows one construction of a heating element according to the invention.

Referring now to the drawings, the warmer apparatus 10 comprises a main housing 12 which is desirably formed from a rigid plastic or similar material and forms a stable base for the warmer apparatus 10. Depending from the main housing 12 is a flexible housing 14. The flexible housing 14 may be attached to the main housing 12 by any suitable means, such as adhesive, welding, heat sealing or the like. The flexible housing 14 may partially or wholly surround the main housing 12. Within the flexible housing 14 is defined a heating element 16 shown schematically in ghost lines in Figure 1.

The flexible housing 14 preferably comprises a rubber, synthetic rubber, rubber composite or other rubber like-material. For example, the housing 14 may comprise a rubber coated fabric web or, more preferably, a neoprene or similar material. Such materials have the advantages of excellent durability in use, as well as good insulating properties for the retention of heat. However, any suitably flexible, durable and insulating material may, in principle be used, of which plastic laminates are an example.

The flexible housing 14 is constructed to retain and surround a food container 18 for food to be warmed. The food container 18 is shown schematically in dotted lines. The food container 18 may be a baby's bottle containing milk or other liquid food or may be a jar, plastic container or the like containing solid or semi-solid food for a baby or infant. Such food containers 18 are usually provided in a limited range of sizes which sizes generally equate to the amount of food which a baby or infant can normally be expected to consume. For example, a baby's bottle will not normally have a capacity greater than about 8 to 10 fluid ounces (approximately 280ml). The flexible nature of the housing 14 permits containers 18 of any size typically suitable for an infant or baby to be accommodated within the flexible housing 14. A closure is provided for the flexible housing 14 which allows the housing 14 to be closed closely about the food container 18. In the illustrated example, the flexible housing 14 is open at its upper end for insertion and removal of the food container 18 and is closeable by means of a drawstring 14A. Other opening and closing means for the flexible housing are also possible, although it is preferable that means for adjusting the closure are provided, to accommodate different sizes of container 18. For example, the closure may be provided with hook-and-loop fasteners (such as VELCRO™) or a number of press fasteners. The opening of the flexible housing 14 may alternatively be formed in a side of the housing, such as at 14B.

The heating element 16 is most preferably attached to the inner face 14C of the flexible housing 14, or may be formed integrally therewith. A preferred heating element 16 comprises an element part 16A formed from an etched conducting substrate, such as an etched metal foil, supported on a flexible plastic web 16B. Such heating elements as such are known. The heating element 16 may be in the form of a laminate having plastic webs on either side of the element part 16A. Alternatively, the flexible housing 14 may be a laminate with the heating element 16 formed as an internal layer thereof. In Fig 2, the element part 16A is shown merely as a schematic representation. The heating element may be shaped to assist in allowing the heating element 16 to conform to the shape of the food container 18. For example, the heating element may comprise a base region 16C which is located in use below the base of the food container 18 and side regions 16D which in use surround the side and, optionally, the top of the food container 18. Cut-outs 16E assist in making the heating element 16 flexible so that it can be brought into close conformity with the external surface of the food container 18. The heating element is connected to a control circuit 20 by means of connectors, terminals or the like 16F. In alternative constructions, a plurality of discrete heating elements may be provided. For example, separate heating elements may be employed respectively proximate the base and sides of the food container 18 in use.

The main housing 12 is preferably formed from a lightweight rigid plastics material. The housing 12 accommodates the main electrical components of the warmer apparatus of the invention. These components include electronic control circuitry shown schematically at 20, an on/off switch 22, one or more indicator lights 24 and a housing, one or more rechargeable cells 26 and associated electrical connections therefore. The electrical components may include a timer which acts to turn the heating element 16 off after a given time period, which time period may be pre-set or may be set, within a given range, by a user. The on/off switch 22 and a timer control may be integrated. The timer may preferably be part of the control circuitry 20. The light or lights 24, which may, for example be LEDs, may include a light which illuminates when the apparatus is in operation and a light which indicates the charge state of the rechargeable cells 26. The rechargeable cells (26) (which in combination may be referred to as a battery) are located in a chamber 26A which conveniently has a removable closure whereby the cells can be replaced when expired or removed for charging in a separate battery charger if required.

The main housing 12 may preferably also include means for optional connection of the control circuitry 20 to external power supplies. A first connection 28 may be to a mains supply and a second connection 30 may be to a nominal 12V supply, such as is normally provided in cars and other vehicles. The connection to these respective supplies may be for recharging the cells 26 and/or for operating the heating element 16 from the supply. In the case of connection to the mains supply, a transformer will normally be required to step the voltage down from the mains voltage. Such a transformer may be provided in the main housing 12. However, this may not be desirable since it can add significant weight to the apparatus. Accordingly, a separate, external, transformer may be provided. In this case, the connections 28, 30 may conveniently be combined into a single connection.

The control circuitry 20, the construction of which can be determined by one skilled in the art, will, on operation of the on/off switch, allow an appropriate current to flow from the cells 26 to the heating element 16 allowing the heating element 16 to heat up and so to warm the food container 18. The flow of current is maintained until (i) the user turns the apparatus off, (ii) the time determined by the timer expires (iii) the temperature within the flexible housing 14 reaches a predetermined threshold or (iv) the cells 26 are exhausted (assuming that the apparatus is not connected to the mains or 12V supply). In whichever of these events is appropriate, the control circuitry 20 may arrange for the heating element 16 to be disconnected from the cells 26, i.e. switched off. The control circuitry 20 also controls the illumination of the light(s) 24. For example a light 24 may be illuminated when the unit is switched on and the heating element 16 is operative. The light 24 may be switched off by the control circuitry when the predetermined threshold temperature is reached. Another light 24 may indicate when power is available from the cells 26 (or external source, as appropriate).

The predetermined temperature within the flexible housing 13 is detected by a temperature sensor 32 which is conveniently a thermostat. The sensor 32 works in conjunction with the control circuitry 20 to turn the heating element 16 off when the threshold temperature is reached. The predetermined threshold is determined in accordance with the temperature which the contents of food container 18 should desirably reach. This temperature may, of course, be higher than the actual desired temperature of the food in the food container 18. The sensor 32 may be mounted at any convenient point within the flexible housing 14 and is connected by suitable connectors to the control circuitry 20.

The control circuitry 20 also includes circuitry for enabling and controlling the re¬ charging of the rechargeable cells 26. Recharging may be effected using either of the external power sources, that is, the mains supply (via a transformer) and a 12V supply, such as in most vehicles. Where sufficient power is available, the control circuitry 20 permits both heating of the heating element 16 and recharging of the cells 26. The nominal 12V supply from a vehicle is in fact variable in terms of the available voltage at any given time. When the engine of the vehicle is not running, the available voltage may drop to, say, 10V whereas when the vehicle engine is running the available voltage may be as high as 15V. The control circuitry includes means to accommodate this variance.

In a preferred arrangement, the apparatus of the invention is provided with 10 cells of nominally 1.1 V- 1.2 V, making a total nominal supply voltage from the cells of about 11V. A preferred cell 26 has a nominal rated capacity (0.2C/1.0V) of 155OmAh and may preferably have a typical capacity of 160OmAh or more, such as 185OmAh. Preferred cells are nickel-metal hydride (Ni-MH) cells. A suitable cell is model number VH 1600 AA High Cap (Type number 55117) from Varta Microbattery GmbH, Ellwangen, Germany. With cells of this or similar rating, two to four heating cycles from a full charge can be achieved. Stated differently, a total useage time of around 45 minutes is achievable. Typical cells can be used for about 500 charge/discharge cycles before they become expired and need to be replaced.

Claims

1. A warmer apparatus, in particular for baby or infant foodstuffs, comprising:

(a) a base housing including, at least one rechargeable battery, electronic control circuitry, means for retaining the battery and providing electrical connections between the battery and the control circuitry,

(b) a flexible housing depending from the base housing adapted to retain a food container to be warmed; and

(c) a flexible heating element contained within the housing and adapted to surround the food container in use, the heating element being connected to said control circuitry.

2. A warmer apparatus as claimed in claim 1 further comprising first connection means for optional connection of the control circuitry to a mains supply;

3. A warmer apparatus as claimed in claim 1 or 2 comprising second connection means for optional connection of the control circuitry to a nominal 12V supply.

4. A warmer apparatus as claimed in claim 1, 2 or 3 wherein the flexible housing comprises a natural or synthetic rubber or rubberised material.

5. A warmer apparatus as claimed in claim 4 wherein the flexible housing comprises a neoprene or neoprene-like material.

6. A warmer apparatus as claimed in any preceding claim wherein the flexible heating element is arranged adjacent both the base and sides of the food container in use.

7. A warmer apparatus as claimed in any preceding claim wherein the flexible heating element is a laminate heating element comprising an resistance heating element attached to at least a first web of plastic material.

8. A warmer apparatus as claimed in claim 7 wherein the heating element comprises an electrically conducting material etched to form a meandering path and arranged on a web of plastic material.

9. A warmer apparatus as claimed in any preceding claim wherein the flexible housing comprises closure means for closing the housing after the insertion of a food container.

10. A warmer apparatus as claimed in claim 9 wherein the closure means comprises a drawstring.

11. A warmer apparatus as claimed in any preceding claim wherein the rechargeable battery comprises a plurality of cells.

12. A warmer apparatus as claimed in claim 1 1 wherein the cells provide a nominal HV- 12V in total.

13. A warmer apparatus as claimed in claim 11 or 12 wherein the cells are nickel - metal hydride (Ni-MH) cells.

14. A warmer apparatus as claimed in claim 1 1, 12 or 13 wherein each cell has a rated capacity of 155OmAh.

15. A warmer apparatus as claimed in any preceding claim further comprising a temperature sensor electrically connected to the control circuitry and operative to determine a temperature within the flexible housing.

16. A warmer apparatus as claimed in claim 15 wherein the temperature sensor is, or acts as, a thermostat, whereby electrical power to the heating element is turned off when the temperature proximate the temperature sensor reaches a predetermined threshold value.

17. A warmer apparatus as substantially hereinbefore described with reference to or as shown in Figures 1 and 2.