A DEVICE FOR COOLING

The present invention relates to a device for cooling, a pressurised container provided with the device and a method of forming a container which cools a substance which it contains upon opening.

It is common to cool containers (for example beverage cans) below an ambient environmental temperature. For example, retailers often store beverage cans in refrigerated areas or refrigerators. A refrigerated area, or a refrigerator, takes up valuable retail space, consumes large amounts of energy and increases the running costs of a retail establishment.

When a customer has bought a beverage can, cooled or otherwise, the beverage may not be consumed immediately. If the beverage within the beverage can is not consumed immediately, this gives the beverage within the beverage can time to reach the temperature of the ambient environment. Take for example a family outing on a warm summer's day. The family may visit a supermarket and purchase some beverage cans for use during the outing. Whether or not the beverage cans purchased by the family are cooled, by the time they have reached the destination for the outing the beverage within the cans will have increased in temperature. The temperature may be anything up to the temperature in which the beverage cans are stored, and can, for example, be 30°C or more. On a warm summer's day, it is not unusual for a person to prefer a cool beverage. Therefore, a warm beverage may be unacceptable.

Various solutions have been posed to this everyday problem. For example, one solution is to place the beverage cans in a cooled environment, for example, a cool bag or cool box. However, on a long journey the cool bag or cool box will also warm up, and eventually reach the ambient temperature of the local environment. In more recent decades, the idea of providing the cool bag or cool box with a power source in order to maintain the space within the cool bag or box at a low temperature has been explored. The power needed to cool the cool bag or cool box is usually drawn from an engine or battery of a vehicle in which people travel to, for example, their outing. Although this solution does solve the problem, it is often an unacceptable solution. For example, use of a powered cool bag or cool box can reduce the fuel economy of the vehicle if powered during transit, or can drain the battery of the vehicle if used when the vehicle is stationary. Furthermore, the powered cool bag or cool box will often be much more expensive than unpowered cool bags or boxes.

For these and other reasons, in recent years people have been investigating the possibility of creating a container which self-cools its contents (e.g. a self cooling beverage container).

Figures Ia to Ic illustrate a prior art self-cooling beverage container. Figure Ia is a plan view of the prior art beverage container. The prior art beverage container takes the general form of a standard beverage can. The beverage container is formed from a cylinder 1. The cylinder 1 may be formed, for example from aluminium, steel or the like. An opening 2 is provided in the cylinder 1. The opening 2 to the cylinder 1 is made by pivoting a lever 3. Figure Ib shows the beverage container in cross section, taken in the direction shown by the arrows A - A in Figure Ia. It can be seen that the beverage container is formed from 2 substantially cylindrical parts. A first cylindrical part Ia is arranged to contain a beverage (not shown). A second substantially cylindrical part Ib is arranged to house or partially house a cooling system. The second substantially cylindrical part Ib is twistable relative to the first substantially cylindrical part Ia to break a seal 4 which separates the two substantially cylindrical parts Ia, Ib. When the seal 4 is broken, heat may be extracted from the beverage contained within the first substantially cylindrical part Ia by cooling elements (not shown) housed in the second substantially cylindrical part Ib. The cooling elements may not necessarily be powered. In one example, for instance, the second substantially cylindrical part Ib may house a desiccant (not shown). The desiccant may draw heat away from the first substantially cylindrical section Ia by evaporation, for example. Figure Ic shows the beverage container in cross section taken in the direction of the arrows B - B shown in Figure Ia.

Figures Ia to Ic schematically depict a prior art self-cooling beverage container similar to that made by Tempra Technology, Brandenton, FL34203, USA (www.tempratech.com).

Although the self-cooling beverage container shown in Figures Ia to Ic is able to cool a beverage, it does nevertheless have its disadvantages. For example, it can be seen that the beverage container is split into two substantially cylindrical sections Ia, Ib. If the first substantially cylindrical section Ia has the capacity to hold an industry standard volume of beverage (e.g. 500ml, 330ml etc.), then the second substantially cylindrical section Ib to which it is attached will necessarily increase the overall size of the beverage container. Increasing the size of the beverage container may make it difficult for existing storage, transport and handling mechanisms and units to accommodate the beverage container. On the other hand, if the self-

cooling beverage container of Figures Ia to Ic is an industry standard size (e.g. having an overall internal volume of just over 330ml, 500ml, etc.) then the second substantially cylindrical part Ib will necessarily take up a large portion of this volume. Therefore, the volume of beverage which can be contained within the beverage container of Figures Ia to Ic will necessarily be less than, for example, 330ml, 500ml, etc.. In order to use this container, a choice would have to be made as to whether to use a larger overall volume to contain a standard volume of beverage or to use a standard volume beverage container to store a lower volume of beverage. This may be undesirable for retailers, manufacturers of beverage containers, and consumers.

It can be seen from Figures Ia to Ic that the means for cooling the beverage are contained in the second substantially cylindrical part Ib. The second substantially cylindrical part Ib is integral to the beverage container, i.e. the beverage container is non-standard. Therefore, a factory which makes standard beverage containers could not easily manufacture the beverage container of Figures Ia to Ic. This means that either a separate production line would need to be set up to construct the beverage container of Figures Ia to Ic, or a different factory would need to be used to make such a beverage container. This would necessarily increase the costs of manufacture of the beverage container, and this cost would probably be passed on to the consumer as a part of the cost of the overall product (for example, a can of beer). Since standard beverage containers (i.e. cans) have been manufactured for decades, their manufacture, packaging and processing, etc, is well established and highly efficient. Therefore, it is not unlikely that the costs associated with manufacturing a self-cooling can as shown in Figures Ia to Ic would be substantial in comparison with the cost of a standard can.

It is an object of the present invention to obviate and mitigate at least one of the advantages of the prior art, whether identified herein or elsewhere.

According to a first aspect of the present invention there is provided a device for use as a cooling element, the device comprising: a receptacle for receiving a fluid, the receptacle being provided with a non-return inlet valve through which fluid may be inserted into the receptacle; an expansion chamber in fluid communication with the receptacle, and arranged to receive fluid which expands from the receptacle, the expansion chamber being provided with an opening through which expanding fluid may flow out of the expansion chamber; and a channel

connecting the receptacle to the expansion chamber, the channel providing an uninterrupted flow path between the receptacle and the expansion chamber.

Preferably the opening provided in the expansion chamber is provided with a non-return outlet valve through which expanding fluid may flow out of the expansion chamber.

Preferably the receptacle is provided with a reservoir for receiving the fluid. The channel may extend into the expansion chamber. Preferably, the channel is provided with a constriction. Preferably the constriction is a venturi. Preferably the channel is defined by walls which are shaped to initially divert the flow of fluid away from expansion chamber.

Preferably the expansion chamber is provided with a plurality of interconnecting channels.

One or both of the receptacle and expansion chamber maybe formed by press forming.

The device maybe provided in a container. A substance to be cooled maybe located in the container. The substance may be a fluid. The substance maybe a beverage. The container maybe a beverage can. Preferably the container is pressurised. Preferably the receptacle is provided with a fluid which is pressurised. Preferably the fluid comprises carbon dioxide.

According to a second aspect of the present invention there is provided a pressurised container in which is located a substance to be cooled, the container being provided with a device for cooling the substance, the device comprising: a receptacle for receiving a fluid, the receptacle being provided with a non-return inlet valve through which fluid may be inserted into the receptacle; an expansion chamber in fluid communication with the receptacle, and arranged to receive fluid which expands from the receptacle, the expansion chamber being provided with an opening through which expanding fluid may flow out of the expansion chamber; and a channel connecting the receptacle to the expansion chamber, the channel providing an uninterrupted flow path between the receptacle and the expansion chamber.

The receptacle and container, and the refrigerant and substance contained respectively therein, are at the same pressure (i.e. they are in steady state equilibrium). Because the refrigerant and substance are at the same pressure, no valves or other mechanisms are required to prevent

expansion of the refrigerant and cooling of the substance. The refrigerant can only expand to cool the substance when the container is opened.

The device and/or container may have one or more of the preferable or alternative features mentioned in relation to the first aspect of the present invention.

According to a third aspect of the present invention there is provided a method of forming a container which cools a substance which it contains upon opening, the method comprising: providing a container; providing a device which comprises: a receptacle for receiving a fluid, the receptacle being provided with a non-return inlet valve through which fluid may be inserted into the receptacle; an expansion chamber in fluid communication with the receptacle, and arranged to receive fluid which expands from the receptacle, the expansion chamber being provided with an opening through which expanding fluid may flow out of the expansion chamber; and a channel connecting the receptacle to the expansion chamber, the channel providing an uninterrupted flow path between the receptacle and the expansion chamber; the method further comprising inserting a cooled or pressurised fluid into the receptacle via the non-return inlet valve before or after the device has been located in the container; and pressurising and sealing the container.

The receptacle and container, and the refrigerant and substance contained respectively therein, are at the same pressure (i.e. they are in steady state equilibrium). Because the refrigerant and substance are at the same pressure, no valves or other mechanisms are required to prevent expansion of the refrigerant and cooling of the substance. The refrigerant can only expand to cool the substance when the container is opened.

The device and/or container may have one or more of the preferable or alternative features mentioned in relation to the first aspect of the present invention.

In the second and third aspects, there is a flow path from the receptacle, through the expansion chamber and into the container (via an opening in the expansion chamber), such that the refrigerant, when expanding, can vent into the container.

Embodiments of the present invention will now be described, by way of example only and in which like features are given like reference numerals, reference to the company and Figures, in which:

Figures Ia to Ic depict a prior art self-cooling beverage container;

Figures 2a and 2b depict a device suitable for facilitating the cooling of a beverage in accordance with an embodiment of the present invention;

Figures 3a and 3b depict a part of the device of Figures 2a and 2b in more detail.

Figure 4 depicts a method of forming the part shown in Figures 3 a and 3b;

Figures 5a and 5b depict another part of the device shown in Figures 2a and 2b;

Figures 6a to 6ά illustrate a method of cooling a beverage in accordance with an embodiment of the present invention; and

Figures 7a to 7c depict a self-cooling beverage container provided with the device of Figures 2a and 2b.

Figure 2a depicts a device which can be used to cool a substance (for example a fluid such as a beverage). The device comprises two parts: a refrigerant receptacle 10 and evaporator 20 (which is sometimes referred to as a cold plate or evaporator plate). As will be described in more detail below, the refrigerant receptacle 10 is in fluid communication with the evaporator 20. A refrigerant may be inserted into the refrigerant receptacle by way of a first non-return valve 11. Fluid may flow into but not out of the refrigerant receptacle 10 via the first nonreturn valve 11. Pressurised fluid may escape from the evaporator 20 by way of a second nonreturn valve 21 located in the evaporator 20. Pressurised fluid may flow out of but not into the evaporator 20 via the second non-return valve 21. Figure 2b illustrates the refrigerant receptacle 10 and evaporator 20 in an end-on view.

The refrigerant receptacle 10 and evaporator 20 can be formed separately and joined together, or formed as an integral unit. The refrigerant receptacle 10 and evaporator 20 are described in more detail below.

Figure 3a shows a side view of the evaporator 20. The evaporator 20 is substantially rectangular in cross-section. The second non-return valve 21 is located in an upper corner of the evaporator 20. The evaporator 20 is provided with an opening 22 through which fluid may flow from the refrigerant receptacle 10 of Figure 2a. Located within the evaporator 20 is a plurality of interconnected channels 23. The channels 23 allow the transit and expansion of fluid which enters the evaporator 20, thereby increasing the heat transfer efficiency. An end-on view of the evaporator 20 is shown in Figure 3b.

The evaporator 20 can be formed from any suitable material, for example a light alloy or plastic. Figure 4 shows that the evaporator may be formed by press-forming a malleable light alloy tube 24 (shown in dashed outline in the Figure). Step and repeat processing may be used to form the channels 23, in much the same way as channels are formed in a radiator.

Figures 5a and 5b show the refrigerant receptacle 10 in more detail. Figure 5a shows the refrigerant receptacle 10 in plan view. It can be seen that the end of the refrigerant receptacle 10 is a circular sector, the arced periphery of which subtends an angle greater than 180°. The first non-return valve 11 is shown disposed on the end (or, in other words, the top face) of the refrigerant receptacle 10. Channels 12 running through the refrigerant receptacle 10 are shown in dashed out line in Figure 5a. An opening 13 is also shown in dashed out line in the Figure. The channels 12 and opening 13 are shown in more detail in Figure 5b.

Referring to Figure 5b, a cross-sectional view of the refrigerant receptacle 10 is shown. The refrigerant receptacle 10 is provided with a reservoir 14 for receiving and storing refrigerant (not shown). The channel 12 extends from the reservoir 14 to the opening 13 via a venturi 15. As can be seen from the Figure, the channel 12 is defined by walls 12a. The walls 12a are arranged to prevent refrigerant flowing directly from the reservoir 14 to the opening 13 (i.e. the walls 12a are shaped to initially divert the flow of fluid away from expansion chamber). As will be described in more detail below, the walls 12a serve to eliminate or reduce the possibility of liquid refrigerant passing directly from the refrigerant receptacle 10 to the evaporator 20. The opening 13 is connected to the opening 22 in the evaporator 20.

The receptacle 10 may be formed from any suitable material and in any suitable way. For example, the receptacle 10 may be formed from a single or multi-part mould, or even press formed. The receptacle 10 may be formed from plastic, metal or any other suitable material.

Use of the refrigerant receptacle 10 and evaporator 20 will now be described in relation to Figures 6a to 6d. Figure 6a shows that a refrigerant in liquid form 40 has been injected into the reservoir 14 of the refrigerant receptacle 10. hi order to keep the refrigerant 14 in liquid form (or a dense gaseous form) when it is in the refrigerant receptacle 10, the refrigerant 40 is added in a low temperature and elevated pressure environment, e.g. a refrigerator, freezer or the like. The refrigerant 40 may be any suitable substance, for example a substance which may easily be cooled to form a liquid state or dense gaseous state, and which is in a gas phase at or around room temperature (or a certain range of temperatures, for example from -10°C upwards). For example, the refrigerant 40 may be carbon dioxide, or a carbon dioxide and nitrogen mix.

When the refrigerant 40 has been injected into the reservoir 14 of the refrigerant receptacle 10, the refrigerant receptacle 10 and the evaporator 20 are placed in a container containing a beverage which is to be cooled. Figure 6b illustrates such a container 50, in which the refrigerant receptacle 10 and evaporator 20 are to be located. The container 50 may be, for example, an aluminium or steel can which holds a soft drink or the like 51.

Figure 6c shows the situation when the refrigerant receptacle 10 and evaporator 20 have been located in the container 50. A lid 52 has been added to the container 50 to seal it from external environment. The container 50 is purged of air and then pressurised as the lid 52 is added to it. This ensures that the refrigerant 40 stays in a liquid or dense gaseous state when the container 50 is sealed from the external environment. It can be seen that the lid 52 is provided with a breakable opening 53. The breakable opening 53 may be broken to expose the contents of the container 50 to the external environment.

Figure 6d shows the situation when the breakable opening 53 of the container 50 has been broken. When the breakable opening 53 of Figure 6d has been broken, the container 50 is no longer pressurised. This means that the refrigerant 40 is no longer restricted to being in a liquid or dense gaseous form. Instead, the refrigerant 40 is able to evaporate. Evaporation of the refrigerant 40 causes a gas 41 to be formed. The only way the gas can escape from the

refrigerant receptacle 10 is via the opening 13 of the refrigerant receptacle 10. The gas flows through the channels 12 provided in the refrigerant receptacle 10 and towards the opening 13. Located at the opening 13 is the venturi 15. The venturi 15 causes the velocity of the gas 41 to increase as the gas 41 enters the evaporator 20, causing the gas 41 to expand more readily thereby assisting the heat transfer. As the gas 41 expands its pressure reduces, which means that it cools (i.e. it undergoes an adiabatic cooling process). As the gas 41 cools it cools the evaporator 20. Cooling of the evaporator 20 cools the beverage 51 contained in the container 50. The gas may vent through the second non-return valve 21. This allows the gas 41 to vent to atmosphere. Figure 6d shows that the gas vents to atmosphere through the beverage 51, but this is not essential. For example, the refrigerant receptacle 10 and / or the evaporator 20 may be shaped so that the opening through which the expanding gas escapes is above the level at which the beverage 51 sits.

It will be appreciated that the rate at which the beverage 51 cools can be controlled by choosing the diameter of the opening defined by the second non-return valve 21 in the evaporator 20 (and/or the pressure at which the second non-return valve 21 opens). For example, it may be desirable to have the beverage 51 cooled slowly and/or so that gas 41 passing through the second non-return valve 21 does not pass through in a violent fashion which may lead to ejection of some of the beverage 51 from the container. The second nonreturn valve may open at any desired pressure, for example 3 psi (21.09 fcN/m ² )

In Figure 5b it was mentioned that the construction of the channels 12 and walls 12a eliminated or reduced the possibility of liquid refrigerant 40 passing from the refrigerant receptacle 10 into the evaporator 20. In general, the walls 12a defining the channel 12 are shaped so as to initially divert the flow of fluid away from the evaporator. Although this is not essential, this will ensure that the maximum amount of liquid refrigerant is kept within the refrigerant receptacle 10 and which is therefore available to expand through the venturi 15, thereby maximising the expansion of the gas and its cooling effects. It can be seen that if the refrigerant receptacle 10 of Figure 5b is rotated by 180° (i.e. it is upside down) the refrigerant cannot flow through the opening 13. Similarly, if the refrigerant receptacle 10 is rotated anticlockwise by 90° the refrigerant will remain within the reservoir 14 and will not pass through the opening 13. If the refrigerant receptacle is rotated 90° from the orientation shown in Figure 5b, it flows to another region of the reservoir. Although in the cross-sectional view in Figure 5b a second region 16b of the reservoir 14 looks smaller in volume than a first region 16a of the

reservoir 14, it can be seen from Figure 5a that due to the fact that the refrigerant receptacle defines a circle sector which extends greater than 180°, the volume of the second region 16b of the reservoir is equal to or exceeds that of first section 16a of the reservoir 14. Therefore, if the refrigerant receptacle 10 rotated 90° anti-clockwise, the refrigerant will not spill through the opening 13.

The process of filling the refrigerant receptacle 10 with refrigerant 40 and the sealing of the container 50 would normally be undertaken in a controlled manufacturing or processing environment. It can be seen that, in contrast with the prior art, the container 50 does not need to be modified in order to incorporate the device needed to cool the beverage 51. This means that the cost of the container 50 is not increased. The device comprising the receptacle 10 and the evaporator 20 may be formed easily and cheaply, so as not to vastly increase the costs of a container provided with such a device. Additionally, the refrigerant used (carbon dioxide) is safe and readily available in, for example, the soft-drink industry. Therefore, the costs involved in providing the refrigerant will not be excessive.

Figures 7a to 7c show a typical example of a container in which the device described above can be used. Figures 7a, 7b and 7c show the device (comprising the refrigerant receptacle 10 and evaporator 20) housed in a beverage can 60 which is provided with an opening 61.

In relation to Figures 6a to 6d, it was stated that the refrigerant 40 was injected into the refrigerant receptacle 10, and that the refrigerant receptacle 10 and the evaporator 20 were then kept in a fridge to keep the refrigerant 40 at a temperature sufficient to keep it in a liquid or dense gaseous state. It will be appreciated that such a process may be undertaken on many occasions to prepare a batch of refrigerant 40 filled refrigerant receptacles 10 attached to evaporators 20 ready to be inserted into beverage containers. Alternatively, the refrigerant 40 may be added to a refrigerant receptacle 10 and evaporator 20 already located in a beverage container (i.e. before a lid 52 on the beverage container is added and the beverage container pressurised). In a further alternative, an empty refrigerant receptacle 10 and evaporator 20 may be located within a container full of fluid. The container could then be purged of air, and charged with pressurised and cooled refrigerant before a lid is added to the container. The refrigerant 40 may then expand when the container 50 is at an ambient temperature (e.g. evaporate) and pass into the refrigerant receptacle 10 by way of its one-way valve 11. Alternatively, the level of refrigerant 40 may be such that it forces its way under pressure into

the refrigerant receptacle 10 by way of its one-way valve 11 as the refrigerant 40 is inserted into the container 50. When the container is opened, the refrigerant in the receptacle 10 will pass through the venturi 15 expanding into and cooling the evaporator 20, which in turn caused the fluid in the container to be cooled.

hi the above embodiments, a plate shaped evaporator has been described. A plate is not essential, but is preferable since it exhibits a large surface area and a small volume. However, all that is required is a body into which the refrigerant may expand (e.g. an expansion chamber). More than one body (e.g. plate) may be in fluid communication with the receptacle to, for example, cool different parts of the substance in which the bodies are immersed.

In the above embodiments, the receptacle and container, and the refrigerant and substance (e.g beverage) contained respectively therein, are at the same pressure (i.e. they are in steady state equilibrium), hi other words, there are no pressure differentials in the container. Because the refrigerant and substance are at the same pressure, no valves or other mechanisms are required to prevent expansion of the refrigerant and cooling of the substance. The refrigerant can only expand to cool the substance when the container is opened. The container may be pressurised to any suitable level, so long as the container is not damaged. For example, standard beverage containers or cans can withstand pressures of up to 120 psi (827.370 kN/m ), and generally 90 psi (620.528 kN/m ² ). Preferably therefore, the container is pressurised up to a level of between 120psi (827.370 kN/m ² ) and 80 psi (551.580 kN/m ² ). For example, the container may be pressurised to a level of 90 psi (620.528 kN/m ² ) or lower then 90 psi (620.528 kN/m ² ), for example 85 psi (586.054 kN/m ² ) or 80 psi (551.580 kN/m ² ). The pressurisation of the container may be undertaken at any suitable temperature, for example at I ⁰ C, or anywhere in the range of -1O ⁰ C to +1O ⁰ C.

In the above embodiments, the second non-return valve 21 of the evaporator 20 is not essential. Instead, an opening may be provided through which expanding fluid may flow out of the evaporator. The use of a non-return valve, however, prevents fluid from flowing into the evaporator and reducing the volume into which fluid from the refrigerant receptacle 10 may expand. Thus, the use of a non-return valve improves the efficiency of the device. The nonreturn valves may open and close at any desirable pressure. For example, the first non-return valve 11 provided in the refrigerant receptacle 10 may open easily (to allow the insertion of fluid), say at or around a pressure of 3 psi (20.684 kN/m ² ). The second non-return valve 21

provided in the evaporator 20 must be able to open easily (to allow the venting of expanding gas), say at a pressure of 3 psi (20.684 kN/m ² ). In the other direction of fluid flow, the nonreturn valves should be able to resist the fluid pressure of the container, which may be pressurised, for example, up to a level of between 120psi (827.370 kN/m ² ) and 80 psi (551.580 kN/m ² ). This prevents fluid from flowing into the evaporator 20, and into the refrigerant receptacle 10 (i.e. in the opposite direction to that intended).

In the above embodiments, a venturi 15 has been described. A venturi 15 is not essential. Any narrow channel connecting the receptacle 10 to the evaporator 20 may be suitable. The channel may be provided with a constriction to aid the expansion of the refrigerant. The constriction (e.g. venturi) may be provided in the receptacle 10 or in the evaporator 20.

With reference to the attached Figures, it can be seen that there is an uninterrupted flow path (i.e. a path along which fluid may flow) between the receptacle and the evaporator. That is, there are no valves, or other moving parts or mechanisms in the flow path between the receptacle and the evaporator. No such moving parts are necessary in the described embodiments. This is because the embodiments rely on a pressurised container in which the cooling device is located becoming de-pressurised in order for a fluid in the container to become cooled. That is, only if the container becomes de-pressurised will the cooling device fulfil its cooling function. Even if the container is dropped, inverted or subjected to a significant force, the device will not operate unless the container is de-pressurised. The possibility of accidental activation of the cooling device is therefore reduced or eliminated. This is a significant advantage when compared with prior art devices which do have valves and differential pressures, or other moving parts or mechanisms in the flow path between the receptacle and the evaporator. Such moving parts or mechanisms may be moved or activated by dropping or inverting the container, possibly causing a cooling device in the container to operate before the container is opened. This could result in the cooling functionality being premature and therefore wasted, or result in damage to (e.g. structural failure) the container.

It may be desirable to prevent the refrigerant receptacle 10 and the evaporator 20 from moving around within the container. For example, it may be desirable to prevent the refrigerant receptacle 10 blocking the opening 61 to the beverage container. Movement, or at least substantial movement, of the refrigerant receptacle 10 and evaporator 20 within the container may be achieved by fixing one or both of the refrigerant receptacle 10 and the evaporator 20 to

the inside of the container. Alternatively, one or both of the refrigerant receptacle 10 and evaporator 20 may be shaped to extend against or at least adjacent to inner surfaces of the container to prevent movement of the refrigerant receptacle 10 and the evaporator 20. Alternatively, the refrigerant receptacle 10 and/or the evaporator 20 may be provided with protruding structures which come into contact with, or extend to a position adjacent to, an inner surface of the inside of the container. In another example, the refrigerant receptacle 10 and/or the evaporator 20 may be provided with restraining clips or the like.

It will be appreciated that the apparatus and method described above allows a substance contained within a pressurised container to be cooled. The substance can be a solid (e.g. in powder form), a liquid or a gas.

It will be appreciated that the embodiments have been described by way of example only. Various modifications may be made to these and indeed other embodiments without departing from the invention as defined by the claims which follow.