WO1997024968A1

WO1997024968A1 - Latent heat storage cartridge and food/beverage container

Info

Publication number: WO1997024968A1
Application number: PCT/AU1996/000834
Authority: WO
Inventors: Peter Lawrence Murphy; Terry Howard Solomon
Original assignee: Thermal Energy Accumulator Products Pty. Ltd.
Priority date: 1996-01-05
Filing date: 1996-12-23
Publication date: 1997-07-17
Also published as: AUPN744596A0

Abstract

A cartridge for storing latent heat, said cartridge comprising: a case (12) having a cavity (20) adapted to removably house at least one capsule (20A, 20B, 20C) containing a phase change substance which has a relatively high latent heat of fusion, said case (12) having a coupling means designed to detachably couple the case to a food or beverage receptacle (16) wherein an external surface of said receptacle (16) is in heat conductive communication with one or more of said at least one capsule (20A, 20B, 20C) whereby, in use, the phase change substance contained within said at least one capsule (20A, 20B, 20C) can be either crystallized or fused using a cooling or heating source, respectively, and thereafter the food or beverage (18) can exchange heat with the phase change substance so that latent heat is either absorbed by or released from said substance as it either fuses or crystallizes and thus the food or beverage (18) is either cooled or heated, respectively. The invention further extends to a food or beverage container comprising a case (12) containing at least one phase change capsule (20A, 20B, 20C) and a food or beverage receptacle (16) in heat exchange contact therewith.

Description

LATENTHEATSTORAGECARTRIDGEANDFOOD/BEVERAGECONTAINER

FIELD OF THE INVENTION

The present invention relates generally to a food or beverage container used for heating or cooling a food or beverage. The invention further relates to a cartridge capable of storing latent heat to be used for heating or cooling food or beverage within a receptacle.

BACKGROUND OF THE INVENTION

A vacuum or THERMOS flask is commonly used to maintain the temperature of a food or beverage contained within the flask. The flask comprises a glass bottle housed within a container constructed of plastic, aluminium alloy, or the like. An annulus air space located between the bottle and an insulation layer, formed within the container, is evacuated and hermetically sealed so that the food or beverage is insulated from ambient temperature conditions . Thus, the vacuum or THERMOS flask acts to maintain the temperature of a hot or cold food or beverage at a desired temperature.

However, the known vacuum or THERMOS flask relies solely on the combined heat insulation properties of the container, insulation layer, air spare, and glass bottle in maintaining the temperature of a food or beverage. Particularly in relatively warm or cold climates the vacuum or THERMOS flask is, by nature of its design, relatively ineffective in maintaining the temperature of a food or beverage at a desired temperature for an extended period.

SUMMARY OF THE INVENTION

An intention of the present invention is to provide a food or beverage container that is relatively effective in maintaining the temperature of a food or beverage at a desired temperature for an extended period. According to a first aspect of the present invention there is provided a food or beverage container comprising: a case having a cavity adapted to removably house at least one capsule containing a phase change substance which has a relatively high latent heat of fusion; and a food or beverage receptacle detachably coupled to the case, said receptacle being capable of containing a food or beverage and having an external surface designed to be in heat conductive communication with one or more of said at least one capsule whereby, in use, the phase change substance contained within said at least one capsule can be either crystallised or fused using a cooling or heating source, respectively, and thereafter the food or beverage can exchange heat with the phase change substance so that latent heat is either absorbed by or released from said substance as it either fuses or crystallises and thus the food or beverage is either cooled or heated, respectively.

According to a second aspect of the present invention there is provided a cartridge for storing latent heat, said cartridge comprising: a case having a cavity adapted to removably house at least one capsule containing a phase change substance which has a relatively high latent heat of fusion, said case having coupling means designed to detachably couple the case to a food or beverage receptacle wherein an external surface of said receptacle is in heat conductive communication with one or more of said at least one capsule whereby, in use, the phase change substance contained within said at least one capsule can be either crystallised or fused using a cooling or heating source, respectively, and thereafter the food or beverage can exchange heat with the phase change substance so that latent heat is either absorbed by or released from said substance as it either fuses or crystallises and thus the food or beverage is either cooled or heated, respectively. Typically, said coupling means comprises a threaded connection formed in the case and adapted to threadably connect to a complementary threaded connection formed in the food or beverage receptacle. Alternatively, the coupling means comprises a clip connector movably connected to the case and designed to operatively engage the food or beverage receptacle.

Typically, the cavity formed in the case is shaped substantially cylindrical, said at least one capsule being disc-shaped and thus designed to removably locate within the cavity. Preferably, there are a plurality of said at least one capsule, each of said plurality of capsules being stacked one upon the other in the cylindrical-shaped cavity of the case.

Typically, the food or beverage receptacle comprises a bottle at least partly contained within a housing. Preferably, the housing has a first opening capable of receiving the bottle, the first opening having a larger cross-sectional shape and size compared to the largest section of the bottle wherein the case and the housing can be connected together so that at least part of the bottle is housed within the food or beverage container.

Typically, the housing has a second opening adapted to receive a neck portion of the bottle, the second opening being of substantially the same cross-sectional shape and size as the neck portion so that, with the housing and case connected together, the bottle is irremovably housed within the food or beverage container.

Typically, the housing has a hollow formed between the first and second openings, the hollow being shaped substantially complementary to the bottle. In one example, the bottle is a flask and the hollow is shaped complementary to the flask. Typically, the housing is elongate and shaped substantially cylindrical, one end of the housing being shaped to substantially contour with the case when connected together.

Typically, the food or beverage container further comprises a first insulation layer located within the housing and shaped substantially complementary to the bottle, the first insulation layer being constructed of a first material having relatively high thermal insulation properties . Preferably, the food or beverage container further comprises a second insulation layer located within the case and shaped complementary to said at least one capsule, the second insulation layer being constructed of a second material having relatively high thermal insulation. Typically, said first and second materials are polyurethane based materials .

Typically, the food or beverage container further comprises a membrane constructed of a material being impermeable to the phase change substance, said membrane configured to locate between the food or beverage receptacle and said at least one capsule so that, in use, in the event of the phase change substance leaking or egressing from said at least one capsule, the membrane substantially prevents the phase change substance from contacting the food or beverage container and thus risking contamination of the food or beverage. Preferably, the membrane is also constructed of a heat conductive material so that heat transfer between the phase change substance and the food or beverage is substantially maximised.

Typically, the food or beverage container further comprises a lid removably connected to the bottle so as to sealably contain the food or beverage within the bottle. In one example the lid is threadably connected to the neck portion of the bottle. Typically, the bottle is constructed of a glass material having relatively high heat resistance and high thermal insulation properties. Typically, the body and cases are constructed of a plastics material. Alternatively, the body and cases are constructed of an aluminium alloy material having relatively high thermal insulation.

Typically, the phase change substance comprises a hydrate salt or a derivative thereof having a relatively high latent heat of fusion. Preferably, when the food or beverage container is used for heating, the hydrate salt has a melting point of between approximately 30°C to 90°C. In one such example the hydrate salt is sodium acetate trihydrate or a derivative thereof, having a melting point of approximately 58°C.

Alternatively, when the food or beverage container is used for cooling, the hydrate salt has a melting point of between approximately -10°C to 5°C. In one such example the hydrate salt is a stoichiometric mixture of ammonium bicarbonate, ammonium chloride, and demineralised water, having a melting point of approximately -4°C.

Typically, the capsule is designed to contain between approximately 50 to 500 ml of the phase change substance. ** More typically, the capsule is capable of containing between approximately 50 to 100 ml of the phase change substance.

In one example, where the hydrate salt is sodium acetate trihydrate, the capsule contains approximately 120 grams of said hydrate salt and is believed to store as latent heat approximately 8 Watt. Hours (WH) of energy.

BRIEF DESCRIPTION OF THE DRAWING

In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a food or beverage container will now be described in some detail, by way of example only, with reference to the accompanying drawing in which:

Figure 1 is a cross sectional view of a food or beverage container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated in Figure 1 there is a food or beverage container shown generally as 10 comprising a case 12 threadably connected to a housing 14. The housing 14 is designed to house a flask-shaped bottle 16 which contains a food or beverage 18, such as coffee. The case 12 has a cylindrical-shaped cavity 20 configured to receive a number of disc-shaped capsules 22A, 22B, 22C. The food or beverage container 10 further comprises a lid 24 threadably connected to a neck portion 26 of the bottle 16. In this example, the case 12 housing the capsules 22 can be considered a cartridge capable of storing latent heat.

Both the housing 14 and the case 12 are cylindrical shaped. In this example, the housing 14 and the case 12 are injection moulded from a plastics material such as polypropylene. The housing 14 and the case 12 are internally lined with a first and second insulation layer 28, 30 respectively having relatively high thermal insulation properties. In this example the first and second insulation layers 28, 30 are constructed of a polyurethane based material.

The flask 16 is constructed of a glass material having relatively high heat resistance and high thermal insulation properties. The neck portion 26 of the flask 16 is provided with a thread 32 for screw connection to the lid 24. The housing 14 is elongate and has at one end a first opening 34 designed to receive the neck portion 26 of the flask 16. The first opening 34 is circular-shaped being slightly greater in size compared to the neck portion 26 of the flask 16. The housing 14 at an opposite end has a second opening 36. The second opening 36 is sufficiently large to receive the largest section of the flask 16.

The first insulation layer 28 of polyurethane internally lines the housing 14 and is shaped substantially complementary to the flask 16. The second insulation layer 30 lines the case 12, and the cylindrical-shaped cavity 20 is shaped so as to removably receive the capsules 22A, 22B, 22C. That is, the capsules 22A, 22B, 22C are disc-shaped being of a slightly smaller diameter compared to the cavity 20. As illustrated in Figure 1 three (3) of the capsules 22A, 22B, 22C are stacked one upon the other in the cavity 20. The uppermost capsule 22A thus directly or indirectly contacts and is in heat conductive communication with a bottom surface of the flask 16.

In this example each of the capsules 22A, 22B, 22C is constructed of a polypropylene material. The disc-shaped capsules 22 contain a phase change substance having a relatively high latent heat of fusion, the phase change substance being selected according to the application or duty the food or beverage container 10 is to perform. For example, if the food or beverage container 10 is to be used for heating, a phase change substance having a melting point of between approximately 30°C to 90°C is selected.

In one example, the phase change substance comprises the hydrate salt sodium acetate trihydrate having a melting point of approximately 58°C. Alternatively, if the food or beverage container 10 is to be used for cooling, a phase change substance having a melting point of between approximately -10°C to 5°C may be selected. In this example, a phase change substance comprising a hydrate salt with a stoichiometric mixture of ammonium bicarbonate, ammonium chloride, and demineralised water, having a melting point of approximately -4°C can be selected. When sodium acetate trihydrate is used each of the capsules 22 contains approximately 120 grams of this hydrate salt. Each capsule 22 is believed to be capable of storing as latent heat approximately 8 Watt. Hours (WH) of energy.

Each of the capsules 22 comprises a body section 40 designed to contain the phase change substance and a roof section 42 sealably connected to the body section 40. A peripheral portion of the roof 42 is ultrasonically welded to a flange portion of the body section 40. Each of the capsules 22 are also provided with a rupture disc (not shown) which is a thin wall section located in the roof section 42. The rupture disc is designed to fail at a predetermined pressure and thus avoid a relatively high pressure rupture of the capsule 22 when, for example, the capsule 22 is overheated.

Use of the food or beverage container 10 described above will now be explained in some detail. In this example, the food or beverage container 10 is used for heating a food or beverage, such as coffee. Thus the hydrate salt sodium acetate trihydrate, having a melting point of approximately 58°C, is selected.

Three (3) capsules 22 are heated using an approximate external heating source, in this example a microwave oven or a pot of heated water. The capsules 22 are heated for a period sufficient to fuse substantially all the hydrate salt sodium acetate trihydrate.

The capsules 22 are then stacked, one upon the other, into the case 12 of the food or beverage container 10. The housing 14 with the flask 16 housed therein is then screwed to the case 12. As illustrated in Figure 1 the capsules 22 are thus sandwiched between an upper surface of the insulation layer 30 and the bottom surface of the flask 16. The uppermost capsule 22A directly or indirectly contacts the bottom surface of the flask 16.

The lid 24 can be removed from the flask 16 and, in this example, a hot food or beverage placed in the flask 16. The lid 24 is then screwed back onto the neck portion 26 of the flask 16 so as to sealably contain the hot food or beverage 18.

As the hot food or beverage 18 cools, under ambient temperature conditions, the hydrate salt sodium acetate trihydrate is likewise cooled via the walls of the flask 16 and the capsules 22. The first insulation layer 28 located within the housing 14 maintains the temperature of the food or beverage 18 near the melting point of the hydrate salt, in this example approximately 58°C, for as long as possible. Similarly, the insulation layer 30 within the case 12 maintains the hydrate salt within the capsules 22 in the liquid form for as long as possible.

Once the hydrate salt begins to crystallise or solidify at approximately 58°C, the latent heat of fusion of the hydrate salt is released and absorbed by the food or beverage 18 contained within the flask 16. Thus, the food or beverage 18 is maintained at a temperature slightly less than 58°C for an extended period of time.

The stack of capsules 22 provides a relatively large volume of the hydrate salt and thus a bank of latent energy is provided. In this example where each of the capsules 22 contains approximately 120 grams of the hydrate salt sodium acetate trihydrate, each capsule 22 is believed to store as latent heat approximately 8 WH of energy. The food or beverage container 10 described will thus hold the food or beverage 18 at a constant temperature for a significantly extended period compared to a known vacuum or THERMOS flask. In contrast the temperature of a food or beverage in the known vacuum or THERMOS flask generally falls at a constant rate from when the food or beverage is originally placed in the flask.

Once the bulk of the hydrate salt within the capsules 22 has crystallised or solidified and released its latent heat of fusion the food or beverage container 10 relies largely on the remaining sensible heat in the hydrate salt together with the insulation materials from which the container it is constructed for maintaining the temperature of the food or beverage 18. The capsules 22 can be removed from the food or beverage container 10 by unscrewing the case 12 from the housing 14 and unloading the capsules 22 stacked within the cavity 20. The hydrate salt sodium acetate trihydrate can then once again be fused by heating the capsules 22 in a microwave oven. The latent heat of fusion of the hydrate salt is thus stored within each of the capsules 22 for future heating purposes.

Although not illustrated, preferably the food or beverage container 10 also comprises a membrane which is located between the case 12 and the housing 14. The membrane is constructed of a liquid impermeable heat conductive material and serves to isolate phase change substance from the flask 16 in the event that one or more of the capsules 22 leaks.

Now that a preferred example of the present invention has been described in some detail it will be apparent to persons skilled in the relevant art that the food or beverage container has at least the following advantages over the admitted prior art: 1. a food or beverage can be maintained at a desired temperature for an extended period of time using the food or beverage container;

2. the food or beverage container can be adapted for both hot and cold applications with relative ease; 3. the food or beverage container is relatively simple in construction and thus relatively easy to clean and service; and

4. by replacing exhausted capsules with charged capsules the food or beverage can be maintained at the desired temperature indefinitely.

It will be apparent to persons skilled in the relevant art that numerous variations and modifications can be made to the food or beverage container described in addition to those already mentioned above without departing from the basic inventive concepts. In one form of the invention the food or beverage container may include a heating element housed within the case and adapted to be powered via an external power supply, such as a car battery. In this example, the phase change substance can be fused in-situ without removing the capsule(s) from the case. The case and housing of the food or beverage container can be constructed of practically any rigid material, such as aluminium. Furthermore, the case can be connected to the housing other than by a screwed connection, provided a capsule containing a phase change substance is in heat conductive communication with a food or beverage receptacle. The various parts of the food or beverage container can take a variety of shapes and are not limited to the shape and configurations described herein. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. A food or beverage container comprising: a case having a cavity adapted to removably house at least one capsule containing a phase change substance which has a relatively high latent heat of fusion; and a food or beverage receptacle detachably coupled to the case, said receptacle being capable of containing a food or beverage and having an external surface designed to be in heat conductive communication with one or more of said at least one capsule whereby, in use, the phase change substance contained within said at least one capsule can be either crystallised or fused using a cooling or heating source, respectively, and thereafter the food or beverage can exchange heat with the phase change substance so that latent heat is either absorbed by or released from said substance as it either fuses or crystallises and thus the food or beverage is either cooled or heated, respectively.

2. A food or beverage container as defined in claim

1 wherein the cavity formed in the case is shaped substantially cylindrical, said at least one capsule being disc-shaped and thus designed to removably locate within the cavity.

3. A food or beverage container as defined in claim

2 wherein there are a plurality of said at least one capsule, each of said plurality of capsules being stacked one upon the other in the cylindrical-shaped cavity of the case.

4. A food or beverage container as defined in any one of the preceding claims wherein the food or beverage receptacle comprises a bottle at least partly contained within a housing.

5. A food or beverage container as defined in claim

4 wherein the housing has a first opening capable of receiving the bottle, the first opening having a larger cross-sectional shape and size compared to the largest section of the bottle wherein the case and the housing can be connected together so that at least part of the bottle is housed within the food or beverage container.

6. A food or beverage container as defined in claim

5 wherein the housing has a second opening adapted to receive a neck portion of the bottle, the second opening being of substantially the same cross-sectional shape and size as the neck portion so that, with the housing and case connected together, the bottle is irremovably housed within the food or beverage container.

7. A food or beverage container as defined in claim

6 wherein the housing has a hollow formed between the first and second openings, the hollow being shaped substantially complementary to the bottle.

8. A food or beverage container as defined in claim 7 wherein the bottle is a flask and the hollow is shaped complementary to the flask.

9. A food or beverage container as defined in claim 8 wherein the housing is elongate and shaped substantially cylindrical, one end of the housing being shaped to substantially contour with the case when connected together.

10. A food or beverage container as defined in any one of claims 4 to 9 further comprising a first insulation layer located within the housing and shaped substantially complementary to the bottle, the first insulation layer being constructed of a first material having relatively high thermal insulation properties.

11. A food or beverage container as defined in claim 10 further comprises a second insulation layer located within the case and shaped complementary to said at least one capsule, the second insulation layer being constructed of a second material having relatively high thermal insulation.

12. A food or beverage container as defined in any one of claims 4 to 11 further comprising a lid removably connected to the bottle so as to sealably contain the food or beverage within the bottle.

13. A food or beverage container as defined in claim 12 wherein the lid is threadably connected to the neck portion of the bottle.

14. A food or beverage container as defined in any one of claims 4 to 13 wherein the bottle is constructed of a glass material having relatively high heat resistance and high thermal insulation properties .

15. A food or beverage container as defined in any one of the preceding claims further comprising a membrane constructed of a material being impermeable to the phase change substance, said membrane configured to locate between the food or beverage receptacle and said at least one capsule so that, in use, in the event of the phase change substance leaking or egressing from said at least one capsule, the membrane substantially prevents the phase change substance from contacting the food or beverage container and thus risking contamination of the food or beverage.

16. A food or beverage container as defined in claim 15 wherein the membrane is also constructed of a heat conductive material so that heat transfer between the phase change substance and the food or beverage is substantially maximised.

17. A cartridge for storing latent heat, said cartridge comprising: a case having a cavity adapted to removably house at least one capsule containing a phase change substance which has a relatively high latent heat of fusion, said case having coupling means designed to detachably couple the case to a food or beverage receptacle wherein an external surface of said receptacle is in heat conductive communication with one or more of said at least one capsule whereby, in use, the phase change substance contained within said at least one capsule can be either crystallised or fused using a cooling or heating source, respectively, and thereafter the food or beverage can exchange heat with the phase change substance so that latent heat is either absorbed by or released from said substance as it either fuses or crystallises and thus the food or beverage is either cooled or heated, respectively.

18. A cartridge for storing latent heat as defined in claim 17 wherein said coupling means comprises a threaded connection formed in the case and adapted to threadably connect to a complementary threaded connection formed in the food or beverage receptacle.

19. A cartridge for storing latent heat as defined in claim 17 wherein the coupling means comprises a clip connector movably connected to the case and designed to operatively engage the food or beverage receptacle.

20. A food or beverage container or a cartridge as defined in any one of the preceding claims wherein the phase change substance comprises a hydrate salt or a derivative thereof having a relatively high latent heat of fusion.

21. A food or beverage container or a cartridge as defined in claim 20 wherein the hydrate salt has a melting point of between approximately 30°C to 90°C.

22. A food or beverage container or a cartridge as defined in any one of claims 1 to 19 wherein the hydrate salt has a melting point of between approximately -10°C to 5°C.

23. A food or beverage container or a cartridge as defined in any one of the preceding claims wherein the capsule is designed to contain between approximately 50 to 500 ml of the phase change substance.