GB2394527A

GB2394527A - Cool packs

Info

Publication number: GB2394527A
Application number: GB0224843A
Authority: GB
Inventors: Barrie Lloyd Reece
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-25
Filing date: 2002-10-25
Publication date: 2004-04-28
Anticipated expiration: 2022-10-25
Also published as: GB2394527B; GB0224843D0

Abstract

A cool pack (1) for use in cooling produce or keeping produce cool comprises a container containing a substantially pure solution of an ionic salt or a mixture of two or more ionic salts in water. The solution is frozen before use of the cool pack (1). The invention also provides a method of maintaining produce, in particular food and/or drink, at a suitable temperature, which method comprises the use of at least one cool pack (1). Preferably the container contains a solution of 7.5% by weight sodium chloride in water. The cool packs are placed in a display cabinet (5) below a shelf (6). The cabinet also includes a control circuit including a temperature sensor (8) for a fan (7). The ionic salt may be sodium chloride, ammonium chloride, calcium chloride, potassium chloride, potassium sulphate or sodium sulphate.

Description

COOL PACKS

The present invention relates to improved cool packs for use in cooling or keeping cool food and/or drink.

Cool packs for use in maintaining food and drink at a low temperature are well known. In particular, such packs may comprise a container filled with an organic solution such as ethylene glycol. These packs are frozen, generally by placement in a domestic freezer, before use. In use the 10 packs are placed adjacent the food or drink to be kept cool and act as a heat sink. In particular, such packs are designed for use in conventional cool bags, being placed at the bottom or sides of such bags with food or drink being placed in the middle of the bag.

15 However, in use, the conventional packs begin defrosting at 0OC and thus water begins condensing on the outside of the pack at this temperature.

Accordingly, the food or drink adjacent the cool pack becomes wet. This is clearly undesirable, as when the food or drink is subsequently removed from the cool bag it will result in the hand of the person removing the 20 item becoming wet. Further, if the outer packaging of the item is made of a material such as cardboard it will become sodden from water condensing on the outside of the packs as they defrost, and may tear.

Accordingly, there is a need for an improved cool pack that is less prone 25 to encountering the problem of water condensation on its exterior at the point of defrosting.

In a first aspect the present invention provides a cool pack for use in cooling produce or keeping produce cool, which cool pack comprises a 30 container containing a substantially pure solution of salt in water. The solution is frozen before use of the cool pack, for example by placement

of the cool pack in a domestic freezer for a suitable length of time, such that in use the cool pack may act as a heat sink.

Preferably, the cool pack is suitable for use in cooling food and/or drink 5 or in keeping food and/or drink cool.

In the context of the present invention, the term "salt" means an ionic salt or a mixture of two or more ionic salts.

10 In the context of the present invention, the term a "substantially pure solution" means a solution consisting essentially of salt and water, in other words no components other than water and salt are present in significant amounts. Preferably, the solution contains 99.0% or more by weight of salt and water, more preferably 99. 5o or more, yet more 15 preferably 99.9o or more.

The salt may suitably be an ionic salt such as sodium chloride, ammonium chloride, calcium chloride, potassium chloride, potassium sulphate or sodium sulphate, or mixtures thereof. The salt is preferably sodium 20 chloride. The salt is preferably non toxic, so that in the event the cool pack is broken or leaks a health hazard is not created. Further, the salt is preferably cheap and readily available, to reduce the cost of the cool pack. 25 The solution may be of any suitable concentration of salt in water. It is preferred that the salt and the concentration thereof are selected such that the freezing/melting point of the solution is in the range of temperatures from 0 C to -300C, more preferably from 0 C to 200C, for example -50C to -15 C. For example, a solution of 7.5% by weight sodium chloride in 30 water may be chosen, giving a freezing/melting point of about -lOoC.

The exact composition of the solution may be chosen to result in a solution having a freezing/melting point appropriate for the desired use of the cool pack. For example, a cool pack to be used to keep frozen foods sufficiently cool during transit will preferably have a lower 5 freezing/melting point than a cool pack to be used to keep fresh produce chilled in order to reduce bacterial growth. Equally, a cool pack to be used to keep fresh produce chilled indirectly by cooling the air around the produce will preferably have a lower freezing/melting point than a cool pack to be used to keep fresh produce chi fled by direct contact.

10 Accordingly, the present invention provides a versatile solution to the problem of providing an improved cool pack, as the cool packs can be designed to suit the particular application for which they are envisaged by selection of the salt and its concentration.

15 The container should clearly be sealed and impermeable to salt solution, to ensure that the solution does not leak from the container. In particular, the container may be a hermetically sealed container.

Preferably the container is made from plastics material. The container is preferably rigid; however it may be partially or fully flexible. The 20 container may be any suitable shape or size. The container may suitably be a container as known for use in conventional cool packs.

The container is preferably at least half filled with the solution.

However, it is clearly necessary that the container is not completely filled 25 with solution, but rather that space is left within the container to allow for expansion of the solution when it freezes.

in one embodiment, the cool pack is colour coded to indicate the composition of the salt solution. For example, the container may be at 30 least partially transparent, preferably fully transparent, and the salt solution may comprise a low concentration of a colorant. Alternatively,

the container may be made from a coloured material. For examples a cool pack with a container made from blue material, or made from transparent material and containing solution with a blue colorant added, may indicate a No NaCl solution.

The present invention further provides, in a second aspect, a set of cool packs, the set comprising two or more cool packs according to the first aspect containing different salt solutions. For example, the set may comprise three different cool packs according to the first aspect, one 10 containing a 3% solution of NaCl in water, one containing a 5% solution of NaCl in water and one containing a 7% solution of NaC1 in water.

Each pack will therefore have a different freezing/melting point, and may therefore be suitably used in different applications. Preferably, each cool pack in the set is colour coded as described above to allow easy 15 differentiation between the different packs.

The present invention also provides, in a third aspect, a method of maintaining produce, in particular food and/or drink, at a suitable temperature, which comprises using a cool pack according to the first 20 aspect.

In one embodiment, the method may comprise cooling the air in the vicinity of the food and/or drink by passing said air over one or more cool packs of the present invention. For example, the food and/or drink 25 may be placed in a container, with the air in said container being maintained at the required temperature by passing it over one or more cool packs of the present invention.

Use of the cool packs of the present invention in such a method is 30 advantageous. Such a method of cooling is particularly preferable for foods and drinks which need to be or are desired to be kept chilled. This

is because the cool packs do not come into direct contact with the food and/or drink, and therefore there is no concern that contact with the cool pack will cause the food and/or drink lo freeze, and thus a cool pack of the present invention may be used that has a relatively low 5 freezing/melting point, e.g. below -50C. The use of a cool pack having a lower freezing/melting point allows the cool pack, once frozen, to be able to effectively cool food and/or drink for a longer period of time.

In particular, the method may comprise the steps of passing air over one 10 or more cool packs of the present invention to cool the air, and then passing the cooled air over the food and/or drink, these steps being repeated as required. Preferably, the food and/or drink is placed in one part of a container, and one or more cool packs of the present invention are placed in another part of the container, and air is circulated within the 15 container so as to pass over the or each cool pack to cool the air and then pass over the food and/or drink so as to cool said food and/or drink.

The air is preferably circulated by means of a fan, preferably an electric fan; for example a battery powered fan. The fan may be located at any 20 position in the container that allows suitable circulation of the air within the container. For example, the fan may be located between the part of the container in which the cool packs are placed and the part of the container in which the food and/or drink is placed.

25 It is preferred that the temperature at which the food and/or drink is kept is monitored. In particular, a temperature sensor may be used to monitor the temperature of the food and/or drink, either directly by taking the temperature of the food and/or drink or indirectly by taking the temperature of the surrounding air or the temperature of the surface on 30 which the food and/or drink is placed. The temperature sensor may be combined with an electronic control system controlling the temperature of

the food and/or drink. When the temperature of the food and/or drink is too high, the control system causes a fan to be switched on to circulate air over the or each cool pack and then over the food and /or drink. Once the temperature of the food and/or drink has reached an acceptably low 5 value, the fan is switched off by the control system.

The container in which the food and/or drink is placed with the cool packs of the present invention may serve simply as a storage container, or it may also be used for display purposes.

In an alternative embodiment, the cool packs of the present invention may be used in a method comprising the step of placing one or more cool packs of the present invention adjacent food and/or drink. In particular, the or each cool pack may be placed at the bottom or at the side of a 15 container, with the food and/or drink placed in the middle of the container. For example, the cool packs may be used in a conventional cool box in the same way as conventional cool packs.

An embodiment of the present invention will now be described, by means 20 of example only, with reference to the drawings, in which: Figure 1 is a cross section through a cool pack according to the present invention; and 25 Figure 2 is a cross section through a display cabinet for food using cool packs as shown in Figure 1.

Figure 1 shows a cool pack 1 for use in maintaining food and/or drink at a suitable temperature. The cool pack 1 comprises a container 2 having 30 substantially rectangular cross section. The container 2 contains a solution 3 that is a substantially pure solution of 7.5 To by weight sodium

chloride in water, which has a freezing/melting point of -10oC. The container 2 is provided with an opening 2a through which the solution 3 was put into the container 2. The opening 2a is sealed by means of a seal 2b and is watertight; this ensures that none of the solution 3 can leak out 5 of the container 2.

Before use, the cool pack 1 is placed in a domestic freezer for at least six hours to freeze the solution 3. Figure 2 shows a number of cool packs 1 being used to maintain food 4 at a suitable temperature in a display 10 cabinet 5. The display cabinet 5 includes a shelf 6, upon which the food 4 is placed, provided with holes 9 and a fan 7 which circulates air within the cabinet 5. The display cabinet 5 also includes a control circuit including a temperature sensor 8, which control circuit controls the fan 7.

15 In use, the cool packs 1 are placed in the display cabinet 5, below the shelf 6. The temperature sensor 8, which is located near the shelf 6, monitors the temperature of the food 4, and when the food 4 is at a temperature above the desired storage temperature the control circuit causes the fan 7 to be switched on. Accordingly, air circulates around 20 the cabinet 5, as shown by arrows, flowing over the cool packs 1 and being cooled, and then flowing over the food 4 and thus causing the food 4 to be cooled. This circulation of air continues until the temperature sensor 8 senses that the temperature of the food 4 has fallen to below the desired storage temperature, and then the control circuit causes the fan 7 25 to be switched off.

Claims

1. A cool pack for use in cooling produce or keeping produce cool, which cool pack comprises a container containing a substantially pure 5 solution of salt in water, wherein the salt is an ionic salt or a mixture of two or more ionic salts.

2. A cool pack according to claim 1, wherein the solution is frozen.

10 3. A cool pack according to claim 1 or claim 2, wherein the solution contains 99.0% or more by weight of salt and water.

4. A cool pack according to any one of claims 1 to 3, wherein the salt is sodium chloride, ammonium chloride, calcium chloride, potassium 15 chloride, potassium sulphate or sodium sulphate, or mixtures thereof.

5. A cool pack according to any one of the preceding claims wherein the salt is non toxic.

20 6. A cool pack according to any one of the preceding claims wherein the salt and the concentration thereof are such that the freezing/melting point of the solution is in the range of temperatures from OoC to -300C.

7. A cool pack according to claim 6, wherein the freezing/melting 25 point of the solution is from OoC to -200C.

8. A cool pack according to any one of the preceding claims, wherein the container is a hermetically sealed container.

30 9. A cool pack according to any one of the preceding claims, wherein the container is at least half filled with the solution.

10. A cool pack according to any one of the preceding claims, wherein the cool pack is colour coded to indicate the composition of the salt solution. 11. A cool pack according to claim 10, wherein the container is at least partially transparent, and the salt solution comprises a low concentration of a colorant.

10 12. A cool pack according to claim 10, wherein the container is made from a coloured material.

13. A set of cool packs, the set comprising two or more cool packs according any one of claims 1 -12, each cool pack containing a different 15 salt solution from the other packs.

14. A set according to claim 13, wherein each cool pack is colour coded. 20 15. A method of maintaining produce at a suitable temperature, which comprises using a cool pack according to any one of claims 1 - 12.

16. A method according to claim 15, which comprises cooling the air in the vicinity of food and/or drink by passing said air over one or more 25 cool packs according to any one of claims 1 - 12.

17. A method according to claim 16, wherein the food and/or drink is placed in a container, with the air in said container being maintained at the required temperature by passing it over the or each cool pack.

18. A method according to claim 16 or claim 17, which comprises the steps of passing air over the or each cool pack to cool the air, and then passing the cooled air over the food and/or drink.

5 19. A method according to claim 18, wherein the food and/or drink is placed in one part of a container, and the or each cool pack is placed in another part of the container, and air is circulated within the container so as to pass over the or each cool pack to cool the air and then pass over the food and/or drink so as to cool said food and/or drink.

20. A method according to claim 19, wherein the air is circulated by means of a fan.

21. A method according to claim 20, wherein the fan is located 15 between the part of the container in which the or each cool pack is placed and the part of the container in which the food and/or drink is placed.

22. A method according to any one of claims 16 to 21, wherein the temperature at which the food and/or drink is kept is monitored.

23. A method according to claim 22, wherein a temperature sensor is used to monitor the temperature of the food and/or drink.

24. A method according to claim 23, wherein the temperature sensor is 25 combined with an electronic control system controlling the temperature of the food and/or drink.

25. A method according to claim 15, comprising the step of placing one or more cool packs according to any one of claims 1 - 12 adjacent 30 food and/or drink.

26. A cool pack for use in cooling produce or keeping produce cool substantially as hereinbefore described and with reference to Figure 1.

27. A method of maintaining produce at a suitable temperature, 5 substantially as hereinbefore described and with reference to Figure 2.