WO2019162705A1

WO2019162705A1 - Cooling system

Info

Publication number: WO2019162705A1
Application number: PCT/GB2019/050531
Authority: WO
Inventors: Nicola Millar; Stuart Edward WATSON; Carl Clement; Christopher James Rosser
Original assignee: Cambridge Consultants Ltd
Priority date: 2018-02-26
Filing date: 2019-02-26
Publication date: 2019-08-29

Abstract

There is disclosed a cooling system for providing localised cooling to a target area to be cooled.The cooling system comprises a source of pressurised liquid refrigerant, a release mechanism and a heat exchanger. In operation refrigerant released from the source cools a working surface of the heat exchanger. A temperature gradient is formed when the working surface is cooled by the refrigerant.The formation of the temperature gradient causes heat from an application surface of the heat exchanger to be transferred away allowing the application surface to be applied to cool the target area.The used refrigerant is vented away from the target area.

Description

Cooling System

The present invention relates to a cooling system and to associated devices, apparatus and methods. The invention has particular although not exclusive relevance to the provision of a localised cooling effect. Many people suffer from medical conditions, such as those characterised by events such as hot flushes (also known as hot flashes) and night sweats. The menopause is an example of a condition that expresses these symptoms, though other conditions also express the same or similar symptoms. The exact cause of these events is still being researched, but it is generally believed to be linked to a hormone imbalance, amongst other factors, which affect the body’s ability to regulate its temperature. This results in an unpredictable pattern of surges in body temperature. Although the net increase in body temperature is small, further symptoms can include blushing, sweating and general uncomfortableness. These symptoms can severely disturb an individual’s sleep and everyday lifestyle. In an attempt to reduce the impact of these symptoms, a variety of over-the-counter sprays and mists have been developed which can be applied to the skin to create a cooling effect by, for example, the expansion of gas, the evaporation of a liquid from the skin, and/or the application of Menthol or other TRPM8 protein agonist which stimulates the nerve system to experience‘cold’. However, current such remedies have a number of disadvantages. For example, such remedies cannot generally be applied discreetly - spraying aerosols or the like often generates noise and hence reduces the user’s ability to discreetly alleviate their symptoms. The containers for such sprays and mists are also generally of a large size, again reducing the user’s ability to discreetly alleviate their symptoms. Moreover, due to such containers being large (typically > 300 ml.) they can be prohibited in high security areas such as on aircraft/international border crossings.

The container will also need to be physically carried by a user, e.g. in their pocket or in a bag, and hence because the container is not readily available relief is not instantly available. Furthermore, repeated application of these sprays/mists can have an undesirable drying effect on the user’s skin.

An alternative to using such sprays is the use of Thermal Electric Coolers (TECs), also known as Peltier Coolers, to provide cooling to the skin. TECs comprise two semiconductors which, when a current is passed across them, act as a heat pump creating a hot and a cold side. However, the need for a hot radiator surface can cause issues, for example when the radiator becomes“blocked ' such as in an enclosed electrical package or under bedcovers; this can inhibit or prevent operation.

Naturally, these systems also require a source of electrical power which, to provide freedom of movement, will typically be in the form of a battery or similar power cell. However, batteries are relatively high cost items which require access to a recharging infrastructure and/or replacement capabilities to be factored into the system’s design.

The likely required cooling power will also require a significant mass battery if a reasonable temperature differential and battery endurance is to be achieved; hence these devices can be unduly cumbersome for a user in terms of portability.

Moreover, control electronics are required to manage TEC performance and prevent excessive cooling, resulting in, for example, skin damage to the user. Furthermore, the incorporation of control electronics increases the complexity and size of the system, as well as introduces more points of failure within the system.

Finally, depending upon the design and power constraints of the TEC system, it may take a significant amount of time for the cooling surface to reach operating temperature. This is undesirable as a user may require an “on-demand” cooling effect.

The present invention seeks to provide a cooling system and associated devices apparatus and methods for meeting or at least partially contributing to the above need. In one aspect of the invention there is provided a cooling system for providing localised cooling to a target area to be cooled, wherein the cooling system comprises: a source of pressurised liquid refrigerant; a release mechanism for releasing the refrigerant from the source into an external environment, whereby the released refrigerant is released in a manner in which the refrigerant is not recovered; a heat exchanger comprising a receiving portion having a working surface for receiving refrigerant released, in use, from the refrigerant source to cool the working surface, and an application surface for applying, in use, localised cooling to the target area to be cooled, whereby the area to be cooled is not exposed to the refrigerant; wherein the working surface and application surface of the heat exchanger are arranged for formation of a temperature gradient, when the working surface receives and is cooled by the refrigerant in use, whereby the formation of the temperature gradient causes heat from the application surface to be transferred away allowing the target area to be cooled; and at least one flow path for venting utilised refrigerant away from the target area.

At least part of the receiving portion of the heat exchanger may be formed of a porous material. The receiving portion of the heat exchanger may be provided with a plurality of fins arranged to increase the flow path of refrigerant flowing via the receiving portion of the heat exchanger.

The source of pressurised refrigerant may comprise at least one membrane configured to retain refrigerant under pressure and the release mechanism may comprise means for piercing the at least one membrane to release said refrigerant.

The release mechanism may comprise at least one valve. The valve may be in the form of a dosing valve configured to provide a preconfigured dose of refrigerant from said refrigerant source. The valve may be configured to provide a controlled dose of refrigerant from said refrigerant source based on the length of time the valve is operated by a user.

The source of pressurised refrigerant may comprise an aerosol container. The source of pressurised refrigerant may comprise a bag on valve container.

The source of pressurised refrigerant may comprise a plurality of refrigerant portions each of which is configured to contain a separate dose of refrigerant under pressure. The release mechanism may be configured for releasing a dose of the refrigerant from at least one of said refrigerant portions whilst the dose in at least one other of said refrigerant portions remains contained under pressure.

The release mechanism and the source of pressurised refrigerant may be configurable in any of a plurality of discrete configurations, relative to one another, wherein in each discrete configuration at least one refrigerant portion may be arranged in a release position in which the release mechanism can engage with that at least one refrigerant portion to release any refrigerant contained therein, and at least one further refrigerant portion is arranged in a non-release position in which the release mechanism cannot engage with that at least one further refrigerant portion to release refrigerant contained therein. The cooling system may comprise a mechanism for moving the refrigerant portions between said release and non-release positions wherein the refrigerant portion moving mechanism may be configured to move a first of said refrigerant portions out of said release position and for moving a second of said refrigerant portions from a non-release position into said release position following engagement of said release mechanism with said first refrigerant portion to release refrigerant from said first refrigerant portion.

The mechanism for moving the refrigerant portions between said release and nonrelease positions may be configured to inhibit movement of a previously used refrigerant portion from a non-release position into said release position. The mechanism for moving the refrigerant portions between said release and non-release positions may be configured to inhibit further movement of the refrigerant portions between release and non-release positions when all the refrigerant portions are exhausted. The refrigerant portion moving mechanism may be configured for manual operation by a user. The refrigerant portion moving mechanism may be configured for operation by an actuator.

The cooling system may comprise a sound damping element arranged to dampen sound generated by vaporisation and expansion of refrigerant released from the source of pressurised refrigerant. The sound damping element may be provided as part of said release mechanism. The sound damping element may comprise at least one of a baffle and a porous material.

The cooling system may comprise an interlock mechanism for inhibiting inadvertent activation of the release mechanism. The interlock mechanism may be configured to require a plurality of independent manual actions before the release mechanism can be activated.

The cooling system may be configured to receive a sensor input from a sensor for sensing at least one physical or physiological parameter, and to trigger operation of the system to provide a cooling effect when said sensor input indicates that the physical or physiological parameter meets at least one predetermined criterion (e.g. exceeds or falls below a predetermined threshold). The system may be configured to receive a signal from a remote device and to trigger operation of the release mechanism responsive to receipt of said signal. The cooling system may comprise at least one vent for venting released refrigerant to atmosphere. The at least one vent may be arranged to vent the released refrigerant at a location and/or in a direction away from the application surface. The at least one vent may be arranged to baffle and supress the noise generated through system operation. The at least one vent may be arranged to disperse the released refrigerant over a wide area.

The receiving portion of the heat exchanger may be arranged to be within a maximum distance of 2.5mm from a point at which the refrigerant leaves the source of pressurised liquid refrigerant when released, optionally within 1mm.

The source of pressurised liquid refrigerant may be provided in a first part and the heat exchanger is provided in the second part wherein the first part and the second part may be configured: for mutual engagement with one another to form an assembled device in which the heat exchanger arranged with the receiving portion positioned for receiving refrigerant when released from the refrigerant source; and for mutual disengagement from one another to allow the second part to be separated from the first part and used, when separated, for application of the application surface of the heat exchanger to provide the localised cooling to the area to be cooled. The second part may be configured to be a hand-held discrete device.

The cooling system may comprise an enclosure formed at least partially from the heat exchanger and a cover member in which the source of pressurised liquid refrigerant is housed in operation. The cooling system may comprise a cover member is configured to be opened to facilitate installation and replacement of the source of pressurised liquid refrigerant. The enclosure may be configured to form a hand-held discrete device.

In one example described herein there is provided a compact, self-contained, device for providing localised multi-dose cooling through the evaporation and expansion of a refrigerant to the ambient environment, comprising: a container for use with the device which is segmented into separate pressurised volumes, allowing the use of pre-dosed volumes of refrigerant; a mechanism which allows indexing of the segmented container so the next segment to be used is aligned into the correct position; a heat exchanger inside which the refrigerant is evaporated and expanded; a means for piercing or otherwise releasing the refrigerant from each of the segmented pressurised volumes in response to a demand for cooling; a means for containing and conveying the released refrigerant to the heat exchanger; and a means for ensuring reliable thermal contact between the heat exchanger and the object to be cooled.

This exemplary device may feature porous material to prolong the time over which the cooling effect is experienced by the user, or both. The indexing mechanism may manually operated by a user or may be operated by a motor. A mechanism may be provided for use with the exemplary device which prevents inadvertent activation by requiring multiple independent actions before a dose is released. An element may be provided for use with the exemplary device that pierces the refrigerant container or operates a valve on the refrigerant container and that incorporating baffles or damping material to reduce sound generated by the vaporisation and expansion of the refrigerant. A container may be provided for use with the exemplary device which incorporates features to dampen sound generated by the vaporisation and expansion of the refrigerant. A sound dampening component may be provided for use in conjunction with the exemplary device to absorb the sound generated when the rupturable membrane is broken. The exemplary device may use sensing of physical, physiological or parameters to predict the need for operation and automatically operates. The exemplary device may be remotely operated.

In one example described herein there is provided a compact, self-contained, device for providing localised cooling through the evaporation and expansion of a refrigerant to the ambient environment, comprising: a refrigerant container for use with the device which is contained within a base unit; a heat exchanger, inside which the refrigerant is evaporated and expanded, which is in a cooled mobile unit, wherein the base unit and cooled mobile unit are mated together to enable refrigerant flow and cooling of the heat exchanger, and wherein the base unit and mobile cooled unit are separated to enable the cooled interface surface on the heat exchanger to be applied to area to be cooled; a means for containing and conveying the released refrigerant to the heat exchanger; a means for mating the two units together and preventing accidental release of refrigerant; and a base which maintains a consumable container of compressed refrigerant in the correct orientation so that only liquid is dispensed to provide the most efficient use of available stored cooling power.

This exemplary device may feature porous material to prolong the time over which the cooling effect is experienced by the user. This exemplary device may feature porous material to reduce the noise generated by the vaporisation and expansion of refrigerant. This exemplary device may operate a valve on the refrigerant container and may incorporate baffles or damping material to reduce sound generated by the vaporisation and expansion of the refrigerant. A container may be provided for use with the exemplary device which incorporates features to dampen sound generated by the vaporisation and expansion of the refrigerant. The base unit and mobile cooled unit may be integrated into one item which cannot be separated.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently (or in combination with) any other disclosed and/or illustrated features. In particular but without limitation the features of any of the claims dependent from a particular independent claim may be introduced into that independent claim in any combination or individually.

Embodiments of the invention will now be described by way of example only with reference to the attached figures in which:

Figure 1 is a schematic diagram illustrating a cooling system;

Figure 2 is a schematic diagram illustrating a device that implements a cooling system according to Figure 1 ;

Figure 3 is an exploded diagram illustrating a device, according to an exemplary implementation of the device shown in Figure 2;

Figure 4a is a perspective view of a component of the device according to the exemplary implementation of Figure 3;

Figure 4b is a sectional view of a component of the device according to the exemplary implementation of Figure 3;

Figure 4c is an exploded view of a component of the device according to the exemplary implementation of Figure 3;

Figure 4d is an exploded view a component of the device according to the exemplary implementation of Figure 3;

Figure 5 is a perspective view of a component of the device according to the exemplary implementation of Figure 3; Figure 6 is a sectional view of the assembled device according the exemplary implementation of Figure 3;

Figure 7 is another sectional view of the assembled device according the exemplary implementation of Figure 3;

Figure 8 is a schematic diagram illustrating another device that implements a cooling system according to Figure 1 ;

Figure 9 is an exploded diagram illustrating a device, according to an exemplary implementation of the device shown in Figure 8;

Figure 10 is a simplified sectional view of a component of the cooling system of Figures 8 and 9; and

Figure 11 is a simplified sectional view of another component of the cooling system of Figures 8 and 9;

Figures 12a and 12b are simplified sectional views illustrating another device that implements a cooling system according to Figure 1 ; and

Figures 13a to 13c are simplified sectional views illustrating another device that implements a cooling system according to Figure 1.

Overview

Figure 1 is a simplified schematic diagram of a cooling system 101. The cooling system 101 comprises a container 103 for containing a refrigerant 105 under pressurised conditions, a heat exchanger 109, and a release mechanism 113 for releasing the refrigerant 105, in a controlled manner from the container 103 towards the heat exchanger 109.

As seen in Figure 1 , the container 103 has an outlet 115 via which the refrigerant is released when the release mechanism 113 is activated.

The heat exchanger 109 has a ‘receiving’ portion or surface 109a for receiving refrigerant 105 output from the outlet 115 of the container 103 and a‘cooling’ or ‘application’ surface 109b for providing a localised cooling effect to a surface to be cooled 11 1 (for example, an area of a user’s body). The release mechanism 113 may comprise any suitable mechanism but in this exemplary system is configured to form an opening at the outlet 1 15 (e.g. by means of a valve or piercing mechanism) when an actuation force A is applied to an end of the container 103 (as oriented in Figure 1).

The container 103 and the heat exchanger 109 are arranged relative to one another to form a flow path (indicated by arrows B) via which the refrigerant flows, when the release mechanism 113 is activated by a user, and the pressurised refrigerant 105 stored in the container 103 is released from outlet 115 into the environment external to the container 103. The flow path conveys the refrigerant released from the outlet 115 of the container 103 over the receiving surface 109a of the heat exchanger 109 to a peripheral edge where the refrigerant 105 is vented into the atmosphere.

Since the environment into which the refrigerant 105 is released is at a lower pressure relative to the pressure of the container 103, as the refrigerant 105 is released, the refrigerant 105 vaporises and expands to provide a cooling effect at the receiving surface 109a of the heat exchanger 109. Accordingly, a temperature gradient forms between the cooling surface 109b (at a relatively higher temperature) and the receiving portion 109a (at a relatively cooler temperature) and, as a result, the cooling surface 109b cools down and can be applied to provide the localised cooling effect to the surface to be cooled 111.

Beneficially, therefore, the cooling system 101 allows a user to provide controlled cooling to a surface of body part (or the like) to be cooled, without the undesirable effects associated with applying a refrigerant 105 directly to the skin.

Whilst in this example the surface 111 to be cooled is human or animal skin, other surfaces could be cooled by the present system, as described later.

A number of examples of how a cooling system similar to that shown in Figure 1 may be implemented will now be described by way of example only.

Multi-dose Cooling Device with Segmented Container

An exemplary cooling device 200 based on the concept exemplified in the system of Figure 1 , which beneficially provides localised multi-dose cooling driven through refrigerant vaporisation and expansion in a compact device, will now be described in more detail with reference to Figures 2 to 7. Referring to Figure 2, which illustrates the cooling device 200 at the system level, the cooling device 200 comprises a segmented refrigerant container 202, a heat exchanger 204, a main body 206 and a release mechanism 212. The disposable container 202 comprises a plurality of segments 202a, 202b, each of which is respectively configured to store refrigerant 208, in its liquid form, under pressure. Each segment of the container 202 is configured to hold the correct volume of refrigerant 208 required for one cooling dose. Each segment of the container 202 comprises an area forming an opening that is sealed with a membrane 210 which may be a separate component or a localised area of the part forming the pressure vessel.

In this example, the release mechanism 212 comprises a piercing element arranged to pierce the membrane 210 of one of the segments 202a, 202b to release the refrigerant 208 stored within that segment 202a, 202b of the container 202. Accordingly, the dose stored in the pierced segment 202b flows out of that segment under pressure. For example, in Figure 2, the piercing element is shown piercing the membrane of segment 202b and the segment 202b is shown to be in the process of releasing the refrigerant stored therein towards the heat exchanger 204. Contrastingly, the other segment 202a remains full and pressurised.

The release mechanism 212 in this example is configured for activation by a user applying a force to a surface of the refrigerant container 202 (a top surface in the orientation shown in Figure 2) as indicated by arrow A in Figure 2.

The heat exchanger 204 has a portion 204a for receiving the refrigerant 208 released from a pierced segment 202b and a‘cooling’ surface 204b for providing the localised cooling effect to the surface to be cooled 218 (for example, an area of a user’s body).

The portion 204a for receiving the refrigerant 208 may be filled with a porous material to act as a noise baffle, absorbing the sound created by refrigerant spraying from the container 202, vaporising and expanding and to add to the thermal inertia of the device. In this example the porous material comprises (but is not limited to) a metal foam. The heat exchanger 204, the segmented container 202 and the piercing element 212 are arranged relative to one another to form a refrigerant flow path (B) in response to the piercing element 212 piercing the membrane 210 of a segment 202b to release the refrigerant stored in that segment. The distance between the receiving portion 204a and the point at which refrigerant will be released from the membrane 210 into the external environment when pierced is advantageously kept as short as possible. By keeping the distance within a maximum of 2.5mm and preferably within a maximum distance of 1 mm‘dead’ volume is minimised and efficiency improved. The flow path (B) between the area of the container 202 punctured by the piercing element 212 and heat exchanger 204 is kept as short as possible so that the maximum possible benefit may be made of the refrigerant’s potential to absorb thermal energy. As refrigerant flows into the heat exchanger 204 the heat exchanger 204 cools as the refrigerant warms to the ambient temperature. When the refrigerant is fully expanded it follows an exhaust path to leave the device via a vent 214 away from the user (indicated by arrows C).

In this example, the receiving portion 204a of the heat exchanger 204 incorporates a number of fins 216 for extending the flow path along which refrigerant 208 released from the refrigerant container 202 will flow in use.

By storing the refrigerant in liquid form in container 202, the latent energy of vaporisation of the refrigerant is significant and, therefore, less refrigerant is needed and the device’s overall mass and associated volume is minimised. This is beneficial because the size of the device can be kept to a minimum and hence the cooling system can manufactured compactly for portability. Moreover, the rapid boiling of the liquid refrigerant as it is vaporised provides rapid cooling, giving a near instantaneous cooling effect. This is advantageous because the user will be able to benefit from a rapid onset of the cooling effect, thereby efficiently alleviating their symptoms.

Reference is now made to Figures 3 to 6, which show an exemplary implementation of the cooling device 200 that was described in general terms with reference to Figure 2, as part of a wrist worn wearable device 300.

Figure 3 is a simplified exploded schematic overview of the wearable implementation 300 and Figures 4a to 4d show, in greater detail, various components of the wearable 300.

The wrist worn wearable 300 comprises a segmented refrigerant container 302, a heat exchanger 304, a cam track piece 306, and a housing 308. As seen in Figure 3 in particular, the refrigerant container 302, heat exchanger 304, cam track piece 306, and housing 308 each have a generally circular cross-section about an axis AA\ The housing 308 comprises an annular sidewall for receiving the other components.

The housing 308 may beneficially be made from a non-thermally conductive material, such that the cooling power generated by release of the refrigerant is focussed towards the heat exchanger’s cooling surface rather than extraneous parts which do not provide the cooling effect. The housing is arranged to seal-in the housed components, thereby inhibiting refrigerant leakage before its cooling capability has been fully transferred to the heat exchanger during device operation. Sealing the housing also helps to absorb noise generated upon the vaporisation and expansion of the refrigerant at its release. The housing 308 also comprises mountings for a securing element 310, in this example a strap with an appropriate fastener 311 for securing the device 300 to a user at a position to be cooled. Thus the device can comfortably be worn in a manner akin to a watch, as well as providing the user with a discreet cooling device. The cam track piece 306 is generally annular with an annular side wall 306a and an annular heat exchanger receiving portion 306b at one end thereof. The heat exchanger receiving portion 306b has a slightly larger diameter than that of the annular side wall 306a of the cam track piece 306. The heat exchanger receiving portion 306b of the cam track piece 306 and the heat exchanger 304 are configured for mutual engagement with one another so that the heat exchanger 304 is coaxially aligned with the cam track piece 306 about axis AA’ and the heat exchanger 304 is received securely in the heat exchanger receiving portion 306b. The annular side wall 306a of the cam track piece 306 and the refrigerant container 302 (when assembled) are mutually configured for reception of the refrigerant container 302 against, or in close proximity to, the heat exchanger 304 to form a sub-assembly for reception in the housing 308. The housing 308 and components of this sub-assembly are mutually configured for reception of the sub-assembly within the housing 308 (i.e. with the heat exchanger 304 positioned for pressing against a user’s skin when the wearable 300 is being worn).

The refrigerant container 302 is configured to be a replaceable and disposable component. The refrigerant container 302 comprises a main body 302a, a rupturable membrane 302b and a cover member 302c in the form a lid configured for mutual engagement with the main body 302a.

Referring in particular to Figures 4a to 4d, which show the refrigerant container 302 assembly in more detail, the main body 302a of the refrigerant container 302 is divided into a plurality of segments 303 (as seen in Figure 4c) each of which is respectively configured to store refrigerant, in its liquid form, under pressure, in the form a dose. The main body 302a, in this example has approximate rotational symmetry with each segment arranged to extend radially outward from a central axis AA’. This arrangement is beneficial for facilitating rotational indexing of the main body 302a relative to the cover member 302c to govern the position of each segment relative to the mechanism for releasing refrigerant from that segment, as discussed in more detail later. Moreover, the circular layout of the container 302 beneficially allows all segments 303 to be filled via a single, central feed system and then plugged or sealed in one action. Alternatively, each segment could be filled individually, with conventional one-way valve technology as seen on disposable cigarette lighters employed.

In this example the container 302 comprises six segments 303. However, any suitable number of segments may be provided although it is envisaged that between six and eight segments is particularly beneficial. Moreover, by having this number of segments 303, the device 300 can provide a number of cooling doses before a user needs to change the container 302. Additionally, between six and eight segments has been determined as generally providing a maximum volume considered acceptable for the wearer of the device 300. Other refrigerants, different segment volumes and different numbers of segments are viable in different examples. Each segment 303 is configured to contain a specific dose of refrigerant. The specific dose is predetermined to provide a total volume of "cooling power" that avoids damaging the skin of the user of the device 300. For example, in this implementation each segment 303 has been configured to store an approximate value of 0.25 ml of refrigerant 1234YF which has been determined to be particularly advantageous for generating a desired cooling effect (although any suitable dose and refrigerant may be used, such as isobutane). In this example, each segment 303 is of an equal size to provide an identical dose. It will be appreciated that different size segments could be used to provide different doses if appropriate.

The membrane 302b is configured for providing a separate, fluid impermeable, seal with a respective sealing surface 316 with each of the segments 303 to retain the pressurised refrigerant in the segment 303 until the membrane sealing that segment is pierced in use. In this example, the rupturable membrane 302b is silicone, or similar material, which seals around the sealing surface 316.

The main body 302a and cover member 302c are configured for mutual engagement with one another to enclose the segments 303 sealed with the membrane 302b. To facilitate engagement between the main body 302a and cover member 302c a snap face 324 is provided on the main body 302a for snapable engagement with a corresponding portion of the cover member 302c to secure the cover member 302c to the main body 302a and form the completed refrigerant container 302 sub- assembly. The cover member 302c also beneficially protects the rupturable membrane 302b from accidental piercing during storage and transport.

The main body 302a and cover member 302c are mutually configured for limited reciprocal movement relative to one another in a direction parallel with a central axis A-A’ when the refrigerant container 302 is assembled. The main body 302a and cover member 302c are also mutually configured for rotational motion relative to one another about central axis A-A’, to allow the refrigerant container 302 to move incrementally, in increments corresponding to the segments 303, as each segment 303 is punctured and the refrigerant spent, to move the next unspent segment into position for subsequent refrigerant release when required. These relative movements are controlled and coordinated by an indexing mechanism as described in more detail later with reference to Figures 6 and 7. Moreover, provided on the cover member 302c is a removable tab 320, which prevents accidental activation of the device 300, via the relative movements discussed above, during transport and storage of the device.

As seen in Figure 4b, the cover member 302c is provided with a piercing element 312 for forming a refrigerant release mechanism as described with reference to Figure 2. The piercing element 312 is provided on a surface that is internal to the refrigerant container 302 when assembled and in a position arranged for piercing one of the segments when, in operation, the main body 302a is moved towards the cover member 302c, for example when a user applies a force to it. The piercing element 312 defines a refrigerant channel 314 for allowing refrigerant to flow out of a segment 303 onto the heat exchanger 304 (shown in Figure 3) when the segment is pierced by the piercing element 312. Thus, when the user applies an appropriate force to the main body 302a the piercing element 312 punctures the rupturable membrane 302b of a given segment 303, thereby releasing the stored refrigerant for that given segment 303 towards the heat exchanger 304 via the refrigerant channel 314.

By providing the piercing element 312 internally with the container 302, it is kept separate from the user, thereby preventing potential injuries, as well as easing alignment issues between the segment 303 and the piercing element 312. In this example, upon release from a given segment, expanded refrigerant follows at least one exhaust path to vent through a gap/vent provided between the refrigerant container 302 and the housing 308, at a location away from the user’s skin. The vent is configured, in this example, to avoid any unnecessary flow resistance when venting the refrigerant.

Also provided on the cover member 302c is a location feature 322 for mutual engagement with a corresponding location feature 336 on the heat exchanger (as seen in Figure 5) to facilitate a proper orientation of the refrigerant container 302 and to inhibit rotational movement of the cover member 302c relative to the heat exchanger 304.

A central shaft 326 locates the lid 302c relative to main body 302a, about which central axis AA’ (shown if Figure 4b) is defined. It is about this central shaft 326 that the main body 302a rotates during operation for positioning of segments 303 in an appropriate alignment with the piercing element 312.

Referring now to Figure 5, which shows the heat exchanger 304 in more detail, the heat exchanger 304 is formed of a material with low thermal resistance to maximise the feeling of cold experienced by the user for a given volume of refrigerant. The heat exchanger 304 comprises a portion 304a for receiving the refrigerant released from a pierced segment 303, and a back plate having a‘cooling’ surface 304b, for providing the localised cooling effect to the surface to be cooled. The heat exchanger 304 also comprises a sealing surface 330 for providing a sealed interface between the heat exchanger and the rest of the assembly. The location feature 336 of the heat exchanger 304 is arranged for mutual engagement with the corresponding location feature 322 of the lid 302c, to facilitate a proper orientation of the refrigerant container 302 and to inhibit rotational movement of the cover member 302c relative to the heat exchanger 304 during indexing and activation of the device 300 as described in more detail later.

The cooling surface 304b of the back plate is configured for contact with the user of the device 300 during operation of the assembled device 300. The back plate may be thick enough to reduce any thermal gradient resulting from the release of the refrigerant onto the heat exchanger 303. Beneficially, the back plate is non-porous and sealed against the device’s main housing 302a to prevent refrigerant directly contacting the user’s skin during use. Accordingly, the design of this heat exchanger facilitates safe cooling.

The receiving portion 304a of the heat exchanger comprises a profiled surface to increase the flow path followed by the refrigerant in operation.

The volume between the receiving portion 304a and the cooling surface 304b is at least partially formed of a porous material. Advantageously, this porous material absorbs the acoustic energy created during the vaporisation and expansion of the refrigerant when the segment 303 containing that refrigerant is ruptured and when that refrigerant exits the storage container via the refrigerant channel 314. Moreover, the use of porous material, through its relatively poor thermal coupling with the user contact surface, thereby increases the duration for which the resulting cold sensation lasts.

Furthermore, through its relatively poor thermal coupling with the cooling surface 304b, as well as its large surface area, the use of porous material can add to the thermal inertia of the device, increase the duration for which the user-experienced cold sensation lasts, and improve the efficiency of the heat exchanger 304 in fully maximising the refrigerant’s capability to absorb heat.

In this example, the porous material has good thermal conductivity and low thermal mass so that little thermal energy from the refrigerant is spent in cooling it, and hence these properties assist in the efficient transfer of the refrigerant’s cooling effect to the surface 304b.

Reference is now made to Figures 6 and 7 which shows the internal features of the wearable, when assembled, in more detail and illustrates, in particular, the indexing mechanism.

Figure 6 shows the device 300 with the main body 302a of the refrigerant container 302 in a primed state in which the device 300 is ready for application but no force has yet been applied to the main body 302a. Figure 7, on the other hand, shows the device in an application state in which a user has applied a force to the main body, as indicated by the arrow A to operate the device.

The refrigerant container 302 includes a biasing mechanism such as a spring or other resilient means for applying a force in a direction opposing the force applied by the user as the user presses down on the main body 302a. Thus when the user releases the main body 302a this biasing mechanism acts to return the main body 302a to its rest state. The main body 302a is provided with at least one cam follower 318 (but in this example a plurality of cam followers). Each cam follower 318 is in the form of a small stud which extends outwardly from the main body 102a and is each configured to engage with a corresponding track 319 that is provided in the cam track piece 306.

The cam followers 318 and the track 319 are mutually configured, with respect to each segment 303 of the main body 302a, to provide the indexing mechanism for providing the incremental segment-by-segment rotation of the main body 302a relative to the cover piece about the main axis AA’.

As seen in Figures 6 and 7, when a user wishes to release a dose of refrigerant from the container 302, the user applies a force to the container main body 302a (as shown by arrow A) to move the main body 302a towards the heat exchanger 304 to pierce one of the segments 303 and release the refrigerant contained therein. As the main body 302a moves towards the heat exchanger 304 in a linear direction, the cam followers 318 move from a first track position 319a into a second track position 319b in which the cam followers 318 are forced, by a generally V shaped section of the track 319 to move rotationally relative to the main axis AA’ a small distance and thus rotate the main body 302a slightly as it reaches the limit of linear movement parallel to that axis (i.e. when the cam followers reach the base of the V shaped portion).

The cam track 319 is configured such that when the user releases the main body 302a and the biasing mechanism acts to return the main body 302a to the rest state, the cam followers 318 are forced to move from position 319b along the cam track as illustrated by arrow B towards position 319c and thus rotate the main body 302a through an angle approximately equivalent to a single segment. The cam track 319 is configured with a generally repeating pattern around the perimeter of the cam track piece 306 with one repetition corresponding to each segment. The cam track 319 is, however, configured to stop further depression and rotation of the main body 302a once the last segment has been spent (e.g. by blocking further movement of the cam follower 318). It can be seen, therefore, that the indexing mechanism ensures that when the device 300 has been operated and the refrigerant contained in a given segment 303 has been released via the refrigerant channel 314 (shown in the inset of Figure 7), the main body 302a is moved incrementally to bring the next (full) segment 303 into the correct position for a further cooling operation. Thus, the user is prevented from reusing a spent segment.

Beneficially, the cam follower track 319 is configured to guide the cam follower 318 into an interlock position 319c in which movement of the cam follower 318 parallel to the main axis AA’ is inhibited by the cam track 319 and thus the main body 302a cannot be pressed until the user manually rotates the main body 302a through a small angle into the next primed state (i.e. corresponding to that shown in Figure 6). This interlock feature acts as a safety lock that helps to avoid inadvertent operation of the device by requiring a plurality of user actions to operate (i.e. the user must depress and rotate the main body substantially simultaneously to effect the release of refrigerant from the refrigerant container).

Packaging the device in a durable body produced of thermally insulating material helps to ensure that only the desired surfaces are cooled.

Summary of Multi-Dose Device In summary, therefore, this implementation provides localised multi-dose cooling driven through refrigerant vaporisation and expansion in a compact device. It consists of a segmented refrigerant container and a heat exchanger with an integrated porous insert, packaged within a compact device. The multi-dose cooling device implementation has a number off benefits as described below.

Firstly, for example, each segment of the container holds the correct volume of refrigerant required for one cooling dose thereby allowing for accurate pre-dosing of the refrigerant. Upon activation of the device, the membrane of one segment is punctured and the entire contents are released and used for cooling. This allows the volume of refrigerant to be pre-set and removes the need to control flow within the device. Therefore, no valves or control loop need to be incorporated, minimising cost and complexity. Moreover, a safety benefit of this constant volume is that the total cooling power is limited for each dose. Therefore, in a wearable implementation (described in more detail below) skin damaging temperatures cannot be reached by the device without releasing the refrigerant within several segments in rapid succession, requiring a conscious user action. Should the container be exposed to abuse when not fitted within the device, then the segmentation aids safety, as again the maximum energy released by a single rupture is reduced.

Segmentation of the container also opens other possibilities, such as having different refrigerants, different volumes, so that the user’s experience can vary across operations.

By at least partially filling each segment with refrigerant in the liquid form, liquid will always be sprayed onto the heat exchanger, regardless of the orientation of the device. This is significant as conventional containers would partially fill with gas after the first use, which would have a much lower cooling power.

By optimising the flow path between container and heat exchanger and keeping any unnecessary volume to a minimum maximises the cooling capability of the device The refrigerant is kept under pressure in liquid form thereby taking advantage of the associated significant latent energy of vaporisation to reduce the amount of refrigerant that is needed. The rapid boiling of the refrigerant as it is vaporised provides rapid cooling, giving near instant cooling effect. By compressing the refrigerant, the overall device mass and volume is minimised. This allows for a more compact device.

The refrigerant container being removable from the device enables the user to quickly recharge the device when required.

In the wearable example, the refrigerant does not come into direct contact with the user’s skin. Therefore, no drying effect of the skin occurs. The heat exchanger has sufficient thermal mass that the cooling power generated by the refrigerant is only sufficient to lower the temperature experienced at the user’s skin to a level which is safe and will not result in skin damage or discomfort. This could also apply for a cooling application in electronics where components have a minimum temperature and sensitivity to thermal shock.

The heat exchanger has sufficient thermal inertia that the contact area will remain cool for a period after the entire segment refrigerant has expanded and vented from the device.

The porous material within the heat exchanger will act as a noise baffle, absorbing the sound created by the refrigerant spraying from the container, vaporising and expanding. The noise of the venting gas will thus be significantly reduced.

The porous material also adds to the thermal inertia and mass of the heat exchanger through its relatively poor thermal coupling with the user contact surface thus increasing the duration for which the cold sensation lasts.

The porous material, with its large contact area, will also add to the efficiency of the heat exchanger in fully maximising the refrigerant’s capability to absorb heat.

Moreover, in its simplest form, the whole device is fundamentally mechanical and requires no electrical components. However it is possible to significantly increase the functionality of the device through integration of electrical control.

Two-Part Cooling Device An exemplary two-part cooling device 800 based on the concept exemplified in the system of Figure 1 , which beneficially provides localised cooling driven through refrigerant vaporisation and expansion, will now be described in more detail with reference to Figures 8 to 11. This exemplary device may be implemented, for example, as a table top or bedside device although other applications are feasible.

Referring to Figure 8, which illustrates the two-part cooling device 800 at the system level, the two-part cooling device 800 comprises a first part in the form of a base unit 801 for holding a refrigerant container 806 and a second part in the form of a compact cooling unit 81 1 comprising the heat exchanger 814 for the application of localised cooling for a user. The base unit 801 and cooling unit 81 1 are configured for mutual detachment from, and reattachment to, one another by a user during use.

The base unit 801 comprises a housing 802 in which a disposable refrigerant container 806 may be held and a release mechanism for releasing refrigerant held under pressure in liquid form in the refrigerant container.

In this example, the release mechanism is in the form of a refrigerant valve 808 which, when operated, will release a controlled dose of refrigerant from the refrigerant container 806 via a refrigerant nozzle 810.

The refrigerant container 806 contains a liquid refrigerant 807 under pressure, having corresponding benefits to those discussed above with respect to the first example.

The base unit 801 is configured to hold the refrigerant container 806 in a correct orientation to ensure that only liquid refrigerant 807 is dispensed in use. In this example, the refrigerant container 806 is provided in the form of an aerosol can, or the like, similar to those available in the consumer market for freeze sprays, deodorant, etc. Integrated inside the refrigerant container 806 is a mechanism for helping to ensure that only refrigerant 807 in the liquid state is dispensed from the device 800 in use. In this example, the mechanism comprises a straw 820, which is arranged to provide a flow path from a base of the container 806 to the valve 808 of the release mechanism, so that dispensed refrigerant 807 is drawn, from the area around a receiving end of the straw 820, near the base of the container 806. The refrigerant valve 808 is, in this example, a flow control valve provided at an upper end of the refrigerant container 806 (as oriented in Figure 8) and at an output end of the straw 820, for controlling the flow of the refrigerant 807 from the refrigerant container 806 to the cooling unit 811 when the device is in operation. In this example, the refrigerant valve 808 is a push valve which opens when pressed and is similar to valves available in commercially available aerosol cans containing freeze spray, deodorant or the like. In this example, the valve 808 is of the open-closed type to allow a user to control how much refrigerant ought to be released from the refrigerant container 806 by varying the time which the valve 808 is held in the open state. The valve 808 is advantageously integrated into the refrigerant container 806 but such an arrangement is not essential.

As an alternative to the open-closed style valve, a dosing valve may be used which dispenses a fixed volume of refrigerant 807 upon each activation, to provide consistent cooling at the cooling surface of the compact cooled unit 81 1 , with respect to the volume of refrigerant being dosed.

The refrigerant nozzle 810 of the release mechanism is arranged to provide a flow path for carrying refrigerant 807 from the refrigerant valve 808 to the cooling unit 811 via, a narrow refrigerant channel 810a, and onto the heat exchanger 814. The nozzle 810 is also provided with a press face 810b arranged to transfer force (as indicated by arrow F) applied by a user to the cooling unit 811 , when the cooling unit 81 land base unit 801 are engaged with one another, to the refrigerant valve 808 to activate flow of the refrigerant 807. In this example, the refrigerant nozzle 810 is similar to the nozzles which can be found on commercially available aerosols for deodorant, spray paint or the like.

The compact cooling unit 81 1 comprises, a body 812 for housing the heat exchanger 814 and at least one (but in this example a plurality) of refrigerant vents 824.

The compact cooling unit 811 and the heat exchanger 814 are arranged for mutual axial alignment with the refrigerant container 806, nozzle 810 and valve 808 of the base unit 801 , when the compact cooling unit 811 and base unit 801 are attached to one another. The relative alignment and orientation of these features facilitates the efficient release of liquid refrigerant 807 from the refrigerant container 806 in response to a user depressing the body 812.

The heat exchanger has a receiving portion 826a and a cooling/application surface 826b, in an analogous manner to the heat exchanger discussed above with regard to the first example. The receiving portion 826a of the heat exchanger is configured to receive refrigerant 807 released and flowing out of the refrigerant container 806 in response to a user applying force (arrow F) to the cooling unit. Thus, the heat exchanger‘captures’ the‘cooling power’ generated as the refrigerant 807 vaporises and expands onto the heat exchanger 814. The distance between the point at which the refrigerant leaves the container 806 to enter the external environment and the receiving portion 826a of the heat exchanger is advantageously kept as short as possible. For example, by keeping the distance between the valve 808 or nozzle 810 within a maximum of 2.5mm from the receiving portion 826a and preferably within a maximum distance of 1 mm the‘dead’ volume is minimised and efficiency improved. The body 812 and heat exchanger 814 of the compact cooling unit 811 are configured to provide a flow path for the refrigerant 807 flowing from the refrigerant container 806 over the heat exchanger 814 and then via an exhaust path to the vents 824 (as generally indicated by the flow path shown by arrows A and B). The heat exchanger 814 is also configured to smooth the rate at which the cooling power is transferred to the cooling surface, such that, in a given localised application, e.g. to a user’s skin, the minimum temperature at the skin is maintained with a margin of safety and ensures that the cooling effect lasts in the region of a minute or so.

Reference is now made to Figures 9 to 11 , which show an exemplary implementation of the two-part cooling device 800 that was described in general terms with reference to Figure 8 in more detail. Figure 9 is a simplified exploded schematic overview of the two-part device 800. Figures 10 and 1 1 show, in greater detail, the base unit 801 and compact cooling unit 811 respectively. As seen in Figures 9 and 10, the base housing 802 of the base unit 801 is configured to securely house the refrigerant container 806, and maintain it securely in a correct orientation, as illustrated in Figure 8 to help ensure that only liquid refrigerant 807 is dispensed. To facilitate this, the housing is profiled at its upper end as seen in Figure 10 (in this example with a generally concave or‘dished’ profile) to conform with a corresponding profile (in this example with a generally convex or‘domed’ profile) of the refrigerant container top to provide an alignment feature 1004 for facilitating alignment between the refrigerant container 806 and the housing 802 to ensure the refrigerant container 806 is correctly positioned for operation. Similarly, the top of the housing 802 (as seen in Figure 10) is profiled to provide a mating feature 1008 (in this example annular or ‘ring’ shaped) for mutual engagement with a corresponding feature of the cooling unit 811. A housing access door 804 is provided on a base of the housing 802 and has an integrated hinge 1002 which allows it to open for receipt of a refrigerant container 806 and to close once the refrigerant container has been received therein. Thus, in operation, the refrigerant container 806 can be placed in/removed from housing 802 with relative ease. The housing access door is also profiled (in this example with a convex or‘domed’ profile) to conform with a corresponding profile (in this example with a concave or‘dished’ profile) of the refrigerant container base to provide an alignment feature 1006 for facilitating alignment between the refrigerant container 806 and the housing 802 to ensure the refrigerant container 806 is correctly positioned for operation. A releasable clip is provided to secure the door 804 closed.

Further security and orientation is facilitated, by provision of a mating feature/key between the refrigerant valve 808 and the compact cooled unit 811 , to ensure that the valve 808 can only be operated when the base unit 801 and cooling unit 811 are correctly mated. This mating feature helps to inhibit accidental activation of the refrigeration valve 808.

As seen in Figures 9 and 11 , the compact cooling unit 81 1 is in the form of a compact, hand held mobile (or‘portable’) device for therapeutic use.

The body 812 of the compact cooling unit 811 is generally disc shaped with a generally elliptical cross-section. In this example, this body 812 is formed of a moulded plastic, making it thermally insulated therefore ensuring on desired surface of the device 800 are cooled.

The underside of compact cooling unit 81 1 (in the orientation of Figure 1 1 ) is configured for engagement with the base unit 801. To facilitate this engagement, the underside is profiled to provide a nozzle engagement cavity 1 1 10a for engaging with the narrow refrigerant channel 810a of the nozzle 810, and to provide a cooling unit press face 11 10b arranged to transfer force applied by a user to the cooling unit 81 1 , when the cooling unit 811 is engaged with the base unit 801 , to the press face 810b of the nozzle 810 (and hence to the refrigerant valve 808 to activate flow of the refrigerant 807). As seen in Figure 1 1 , the underside of compact cooling unit 81 1 is also provided with the vents 824 for venting dispensed refrigerant in use. By configuring the vents 824 on the underside in this way the vents 824 are beneficially arranged to vent refrigerant away from the cooling surface 826b of the heat exchanger 814 and thus away from the skin of a user.

The heat exchanger 814 is adapted to seal against the body 812 of the compact cooling unit 811 to prevent any undesirable leakage of refrigerant 807 onto the area undergoing cooling. In this example, the heat exchanger 814 is produced from a high conductivity material, such as aluminium or copper, thereby maximising the efficiency of the device.

The external profile of the refrigerant receiving side 826a of the heat exchanger 814 comprises a plurality of pins 815 configured for extending the flow path along which refrigerant flows in use (although a plurality fins, ridges or the like could also be used). In this example, this external profile is at least partially filled with porous metal foam 816. As in the first example, this porous material absorbs the noise generated upon refrigerant vaporisation and expansion. Furthermore, through its relatively poor thermal coupling with the cooling surface 826b, as well as its large surface area, the porous material 816 respectively increases the duration for which the user- experienced cold sensation lasts and improves the efficiency of the heat exchanger 814 in maximising the refrigerant’s capability to absorb heat.

There may be a number of possible ways to insert the porous material into the heat exchanger. However, in this example, the porous material is provided in the form of a disk of porous metal foam, as best seen in Figure 9, which is then pressed into place upon assembly of the heat exchanger 814 with the body 812 of the compact cooling unit 812. In this example the porous material has good thermal conductivity and low thermal mass so that little thermal energy from the refrigerant is used to cool it and this is efficiently transferred to the cooling surface 826b of the heat exchanger. In other examples these properties may be altered to affect the temperature at the interface plate and duration of the effect.

As seen in Figures 9 and 1 1 , a temperature sensitive display 818 is provided on the cooling surface 826b of the heat exchanger 814. This temperature sensitive display 818 is configured such that when the device 800 is in use, the heat exchanger cools and the temperature sensitive display 818 therefore reacts to this change in temperature and the display changes accordingly. In this example, the temperature sensitive display 818 thus provides an indication of how cold the device is to the user. Accordingly, the temperature sensitive display 818 can indicate, to the user, if the device is in a state suitable for providing the desired cooling effect, or if the device is too cold for safe operation. The temperature sensitive display is located for visibility to a user during (both during the day and at night) and to avoid the likelihood of being obscured when the device is in use.

The temperature sensitive display 818 is, in this example, a heat sensitive sticker which displays a warning triangle if the device is too cold for safe use, i.e. too much refrigerant has been released from the refrigerant container. The sticker is also configured to display first, second and third snowflakes which, when at the body of the heat exchanger 814 is within a range of given temperatures, indicate three different temperatures ranges associated with stages of device coolness to the user (e.g. one snowflake indicated means the device has reached an initial cooling temperature, whilst three snowflakes indicated means the device is at a safe cooling temperature which provides the greatest cooling effect). An alternative to this sticker would be to apply temperature sensitive paint directly onto the cooling surface which has an associated use state which changes in response to temperature fluctuations.

Summary of Two-Part Device

In summary, therefore, it can be seen that this example relates to a two-part cooling device that provides cooling using vaporisation and expansion of pressurised refrigerant to the ambient environment from a container through a porous heat exchanger which acts as a heat sink as well as supressing the noise generated from the gas expansion. The heat exchanger is mounted in a compact cooled unit which can advantageously be removed from the base container, which contains the refrigerant container, to provide localised, targeted cooling.

Once the valve is operated, refrigerant is allowed to flow / spray directly into the heat exchanger matrix. Beneficially, the path between the container and heat exchanger is kept as short as possible so that the maximum possible use is made of the refrigerant’s potential to absorb thermal energy. Beneficially, by separating the energy store and the cooling part, the cooling part can be kept more compact and ergonomic, making its use more effective and flexible in therapeutic applications. Moreover, the refrigerant container can be quickly replaced when required as opposed, for example, to having to wait for an internal battery to recharge for an electrical system.

Advantageously, the temperature drop at the cold surface can be governed through control of the refrigerant flow through the valve. The user can be given control with a simple variable flow valve or the flow can be set to a fixed rate with a volumetric dosing valve. The design of the device also helps to ensure that the valve cannot be accidently operated to release refrigerant without detachable unit in place.

The design of the device makes it very simple to operate. The device is also purely mechanical, requiring no electrical components with associated manufacturing costs and packaging requirements. Thus the device is simple to manufacture with a low production cost and is simple and robust making it reliable in operation. The consumable can make advantageous use of already available fast moving consumer goods processes and components which are recyclable. The use of refrigerant means no heat is generated through the cooling process and cooling cycles can be run repeatedly with no need to wait for the device to reset between operations. Moreover, no waste by-product is generated from a chemical process which must then be managed: the used refrigerant simply dissipates to the atmosphere.

The base unit housing is beneficially designed to control the orientation of the refrigerant container so that refrigerant in the liquid state is always dispensed to the heat exchanger, giving optimum cooling. As with the first example, another advantage of this device it that refrigerant does not come into direct contact with the surface to be cooled. In therapeutic applications this prevents skin drying effects from repeated uses.

The refrigerant is kept under pressure in liquid form thereby taking advantage of the associated significant latent energy of vaporisation to reduce the amount of refrigerant that is needed. The rapid boiling of the refrigerant as it is vaporised provides rapid cooling, giving near instant cooling effect. By compressing the refrigerant, the overall device mass and volume is minimised. This allows for a more compact device.

The refrigerant does not come into direct contact with the user’s skin. Therefore, no drying effect of the skin occurs. The heat exchanger has sufficient thermal mass that the cooling power generated by the refrigerant is only sufficient to lower the temperature experienced at the user’s skin to a level which is safe and will not result in skin damage or discomfort. This could also apply for a cooling application in electronics where components have a minimum temperature and sensitivity to thermal shock.

Moreover, in its simplest form, the whole device is fundamentally mechanical and requires no electrical components. However it is possible to significantly increase the functionality of the device through integration of electrical control. For example, in a therapeutic application, this could detect and activate in the very early stages of a hot flush to limit the user’s discomfort.

Integrated Compact Devices Two variations of an integrated compact device based on the concept exemplified in the system of Figure 1 , which beneficially provides localised cooling driven through refrigerant vaporisation and expansion, will now be described in more detail with reference to Figures 12 and 13.

A first variation of the integrated compact device 1200 is shown in Figure 12. This variation is particularly beneficial for implementation as a table top or bedside device although other applications are feasible.

Referring to Figure 12, the first variation of the integrated compact device 1200 comprises a refrigerant container 1202 housed in a substantially sealed enclosure 1204 formed of a base portion comprising a heat exchanger 1206 and a cover 1208.

The refrigerant container 1202 in this example is in the form of a compact aerosol container or the like although it will be appreciated that other forms of refrigerant container may be used. The release mechanism in this example comprises a metered dose valve for providing a controlled dose of refrigerant when actuated. For example a valve such as those used for metered dose inhalers (MDIs) or the like may be used. A refrigerant dispersement device 1214 is provided on the valve to aid dispersement of the refrigerant from the container 1202 when the valve is operated.

The cover 1208 in this example is in the general shape of an elongated dome but may be any suitable shape. The cover 1208 is configured to be opened as shown in Figure 12b to allow the refrigerant container to be installed in the enclosure 1204 and replaced when necessary. In this example the cover 1208 is mounted to the base portion by a hinge or the like but it will be understood that the cover 1208 may be mounted by any suitable means and may be completely removable. At least one vent 1210 is provided in the surface of the cover 1208 for venting released refrigerant away from the area of application in use. The cover 1208 is formed of an appropriate thermally insulating material.

The heat exchanger 1206 comprises a receiving portion 1206a for receiving refrigerant output from the refrigerant container 1202 and a cooling/application surface 1206b for providing a localised cooling effect to a surface to be cooled in a similar manner to the previously described examples. In this example the heat exchanger is shown forming substantially an entire base portion of the device 1200 but it will be appreciated that the heat exchanger 1206 may only form part of the base portion.

The device 1200 is also provided with a depressible actuation member 1212 that extends through the cover. The actuation member 1212 is configured to engage with the refrigerant container, when the cover 1208 is closed, to assist alignment of the refrigerant container 1202 in the correct location. In operation, when a force (as illustrated by arrow F) is applied to the actuation member 1212, this force is transferred to the refrigerant container and hence operates the valve to release a dose of refrigerant.

The container 1202, the heat exchanger 1206 and refrigerant dispersement device 1214 are configured to form flow paths (as indicated by arrows B) via which the refrigerant flows, when the release mechanism is activated by a user and pressurised refrigerant stored in the container is released. The flow paths convey the released refrigerant towards the receiving portion 1206a of the heat exchanger. Following release, the refrigerant flows to the periphery of the enclosure 1204 via an exhaust path where the refrigerant is vented via the vent 1210 into the atmosphere. The distance between the point at which the refrigerant leaves the container 1202 to enter the external environment, and the receiving portion 1206a of the heat exchanger, is advantageously kept as short as possible. For example, by keeping the distance between the output of the valve/dispersment device within a maximum of 2.5mm from the receiving portion and preferably within a maximum distance of 1 mm‘dead’ volume is minimised and efficiency improved.

As with the other examples, as the refrigerant is released the refrigerant vaporises and expands to provide a cooling effect at the receiving portion 1206a of the heat exchanger. Accordingly, the cooling surface 1206b cools down and can be applied to provide the localised cooling effect to the surface to be cooled. Referring to Figure 13, the second variation of the integrated compact device 1300 comprises a refrigerant container 1302 housed in a substantially sealed enclosure 1304 formed of a base portion comprising a heat exchanger 1306 and a cover 1308.

The refrigerant container 1302 in this example is in the form of a bag-on-valve type container, or the like, although it will be appreciated that other forms of refrigerant container may be used. A bag-on-valve type container is, however, particularly advantageous because it allows the device to be operated in any orientation without having a significant impact on the effectiveness of operation. The bag-on-valve container is also particularly beneficial as it allows effective liquid refrigerant release from a small container (e.g. conforming to air safety regulations) even when almost empty. Accordingly, using a bag-on-valve container in a hand-held device helps to aid compactness and to ensure that the device can be used during flights. Moreover, a bag-on-valve type container can use environmentally friendly gases such as pressurised air or nitrogen to force the product out of the container because, unlike traditional aerosols, these gasses will not mix with the product. Bag-on-valve type containers are also known to reduce spray noise which is particularly beneficial in a hand-held version of the cooling device where a user may want to use the device discretely.

The release mechanism in this example comprises a metered dose valve for providing a controlled dose of refrigerant when actuated. For example a valve such as those used for metered dose inhalers (MDIs) or the like may be used. A refrigerant dispersement device 1314 is provided on the valve to aid dispersement of the refrigerant 1314 when the valve is operated. In this example, the components of the enclosure 1304 are configured to house the refrigerant container 1302 generally parallel to the base portion and heat exchanger 1306. Such a configuration beneficially aids compactness.

The cover 1308 in this example is in ergonomically shaped to allow comfortable handling by a user holding the cover but may be any suitable shape. The cover 1308 is configured to be opened as shown in Figure 13c to allow the refrigerant container to be installed in the enclosure 1304 and replaced when necessary. In this example the cover 1308 is mounted to the base portion by a hinge or the like but it will be understood that the cover 1308 may be mounted by any suitable means and may be completely removable. At least one vent 1310 is provided in the surface of the cover 1308 for venting released refrigerant away from the area of application in use. The cover is formed of an appropriate thermally insulating material.

The heat exchanger 1306 comprises a receiving portion 1306a for receiving refrigerant output from the refrigerant container 1302 and a cooling/application surface 1306b for providing a localised cooling effect to a surface to be cooled in a similar manner to the previously described examples. In this example the heat exchanger is shown forming substantially an entire base portion of the device 1300 but it will be appreciated that the heat exchanger 1306 may only form part of the base portion. In order to facilitate operation of the valve of the refrigerant container 1302, the heat exchanger 1306 is provided with a thermally conductive actuation platform 1316 extending generally perpendicularly from the heat exchanger 1306 against which the dispersement device 1314 may be pressed to activate the valve of the refrigerant container 1302 during operation.

The device 1300 is also provided with a depressible actuation member 1312 that extends through the cover. The actuation member 1312 is configured to engage with the refrigerant container, when the cover 1308 is closed, to assist alignment of the refrigerant container 1302 in the correct location. In operation, when a force (as illustrated by arrow F) is applied to the actuation member 1312, this force is transferred to the refrigerant container and hence operates the valve to release a dose of refrigerant. In this example the actuation member 1312 is configured to be removable (as seen in Figure 13b) to allow the cover 1308 to be opened to replace a refrigerant container, and to be reattached after the cover 1308 is closed again.

The container 1302, the heat exchanger 1306 and refrigerant dispersement device 1314 are configured to form flow paths (as indicated by arrows B) via which the refrigerant flows, when the release mechanism is activated by a user and pressurised refrigerant stored in the container is released. The flow paths convey the released refrigerant towards the receiving portion 1306a of the heat exchanger. It will be appreciated that, in this example, the dispersement device 1314 may be configured to dispense the refrigerant asymmetrically towards the heat exchanger side of the refrigerant container 1302. To ensure that such asymmetric release of the refrigerant is directed in the correct direction, the container 1302 and/or dispersement device 1314 may be provided with an alignment feature to facilitate correct alignment with a corresponding alignment feature provided on the enclosure 1304.

Following release, the refrigerant flows towards the periphery of the enclosure 1304 via an exhaust path where the refrigerant is vented via the vent 1310 into the atmosphere. The distance between the point at which the refrigerant leaves the container 1302 to enter the external environment, and the receiving portion 1306a of the heat exchanger, is advantageously kept as short as possible. For example, by keeping the distance between the output of the valve/dispersement device within a maximum of 2.5mm from the receiving portion and preferably within a maximum distance of 1 mm‘dead’ volume is minimised and efficiency improved.

As with the other examples, as the refrigerant is released the refrigerant vaporises and expands to provide a cooling effect at the receiving portion 1306a of the heat exchanger. Accordingly, the cooling surface 1306b cools down and can be applied to provide the localised cooling effect to the surface to be cooled.

Modifications and alternatives

Detailed descriptions of cooling systems have been described above. As those skilled in the art will appreciate, various modifications and changes to the above systems are possible and some of these will now be described.

The above described multi-dose cooling device has a rupturable membrane sealing each of the refrigerant containing segments, and this membrane is pierced to release refrigerant. It will be appreciated that this is not essential because, instead, each segment may include a valve (e.g. a flow control or dosing valve) which is operated to release the refrigerant. In this alternative, the piercing element could be replaced with a hollow tube or equivalent rigid member configured to operate the valve on each segment of the refrigerant container. This valve could also be used for filing the consumable.

The segments of the segmented refrigerant container may be modified to receive different volumes of and/or to release different refrigerant(s), such that the user’s experience can vary across releases.

The rupturable membrane has been described as being made of silicone, or other similar materials. Alternatively, different materials, such as foil which tears upon piercing, as well as materials which allow a rapid flow of refrigerant, may be used. Another alternative is to use a section of the pressure container wall which locally ruptures upon pressure from the piercing element

The piercing element is described in the above systems as being part of the refrigerant container assembly. Alternatively, this element could be removed from the container assembly and integrated into the heat exchanger component instead. This would allow the piercing element to act as an additional heat exchanger surface area and provide more thermal mass.

The refrigerant, according to the above systems, is vented into the atmosphere by one or more vents. In the alternative, at least one dedicated vent may be provided, which acts as a flow restrictor and controls the flow of refrigerant from the system therefore affecting the rate and duration of cooling. This effect may be controllable by the user. The vent(s) may alternatively or additionally be arranged to baffle and supress the noise generated through system operation. The vents may alternatively or additionally be arranged to disperse the released refrigerant over a wide area.

The porous material inside the heat exchanger has been described as being a metal foam. This is not essential, as the heat exchanger’s porous material may alternatively or additionally incorporate alternatives, such as a stack of meshes, coarse beads, or other similar materials. Whilst the heat exchanger itself may be made from aluminium and copper, other alternatives, such as high conductivity ceramic, may also be used.

Fins, ridges and pins have been described as possible features of the heat exchanger’s external profile with respect to the devices above. Alternatively or additionally, other heat exchanger profiles may be used.

Whilst the application/cooling surface/back plate surface in the above examples is smooth this surface of the heat exchanger in any of the above devices may be textured, such as with dimples, to maximise the user’s perception of cool. Additional insulation may also be placed on the disk to make the application surface a‘ring’ or other shape rather than a plane circle as shown.

In the above multi-dose device, the refrigerant container and the heat exchanger have been described as being separate parts which are fitted together. An alternative arrangement of the device would be to have the heat exchanger and container integrated as one part. This would potentially reduce the cost and overall volume of the device.

To maintain a positive contact pressure between the user and the device, the strap of the wearable device may be mechanically elastic. As an alternative to the strap as a securing means, the device could be stuck directly to the user’s skin or, instead, secured by another means. Another alternative is for no strap to be employed and the user to hold the device in place, applying pressure as required.

The housing of the devices described above may be modified to include further noise baffles to improve noise suppression.

An automated system, capable of initiating cooling operations through response to data from sensors, could be incorporated into the above described. For instance, the wearable device might include a heart rate sensor, control electronics and battery may be embedded in the main housing, the strap or a separate linked device. When the control algorithm detects the onset of a menopause hot flush, an electric actuator integrated into the housing rotates the refrigerant container around the cam track, resulting in the next segment’s membrane being punctured and cooling occurring. This alternative may be useful in case a user experiences“night-sweats”, because the system will automatically provide the wearer with a dose of refrigerant. This may improve the user’s ability to have a comfortable uninterrupted sleep. Alternatively, other physiological signals, such as Galvanic Skin Resistance, could also be monitored, with the sensor not necessarily mounted within the device.

Similarly, other means of automatically releasing refrigerant could be employed, such as the receiving of a remote signal to initiate cooling.

Other applications of the devices disclosed herein, include but are not limited to: enhanced sports performance, during medical procedures where conventional equipment is not practical, veterinary applications, enhancing immersive experiences such as 3D IMAX cinema screenings and virtual reality (VR), prolonging the display or transport period of temperature sensitive goods, bringing food and drink to a desired temperature immediately prior to consumption or in high performance electrical equipment.

Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Claims

1. A cooling system for providing localised cooling to a target area to be cooled, wherein the cooling system comprises:

a source of pressurised liquid refrigerant;

a release mechanism for releasing the refrigerant from the source into an external environment, whereby the released refrigerant is released in a manner in which the refrigerant is not recovered;

a heat exchanger comprising a receiving portion having a working surface for receiving refrigerant released, in use, from the refrigerant source to cool the working surface, and an application surface for applying, in use, localised cooling to the target area to be cooled, whereby the area to be cooled is not exposed to the refrigerant; wherein the working surface and application surface of the heat exchanger are arranged for formation of a temperature gradient, when the working surface receives and is cooled by the refrigerant in use, whereby the formation of the temperature gradient causes heat from the application surface to be transferred away allowing the target area to be cooled; and

at least one path for venting utilised refrigerant away from the target area.

2. A cooling system as claimed in claim 1 , wherein at least part of the receiving portion of the heat exchanger is formed of a porous material.

3. A cooling system as claimed in claim 1 or 2, wherein the receiving portion of the heat exchanger is provided with a plurality of fins arranged to increase the flow path of refrigerant flowing via the receiving portion of the heat exchanger.

4. A cooling system as claimed in any preceding claim wherein the source of pressurised refrigerant comprises at least one membrane configured to retain refrigerant under pressure and wherein the release mechanism comprises means for piercing the at least one membrane to release said refrigerant.

5. A cooling system as claimed in any of claims 1 to 4 wherein the release mechanism comprises at least one valve.

6. A cooling system as claimed in claim 5 wherein the valve is in the form of a dosing valve configured to provide a preconfigured dose of refrigerant from said refrigerant source.

7. A cooling system as claimed in claim 5 wherein the valve is configured to provide a user controlled dose of refrigerant from said refrigerant source based on the length of time the valve is operated by a user.

8. A cooling system as claimed in claim 5 or 6, wherein the source of pressurised refrigerant comprises an aerosol container.

9. A cooling system as claimed in claim 5 or 6, wherein the source of pressurised refrigerant comprises a bag on valve container.

10. A cooling system as claimed in any of claims 1 to 6, wherein the source of pressurised refrigerant comprises a plurality of refrigerant portions each of which is configured to contain a separate dose of refrigerant under pressure and wherein the release mechanism is configured for releasing a dose of the refrigerant from at least one of said refrigerant portions whilst the dose in at least one other of said refrigerant portions remains contained under pressure.

11. A cooling system as claimed in claim 10, wherein the release mechanism and the source of pressurised refrigerant are configurable in any of a plurality of discrete configurations, relative to one another, wherein in each discrete configuration at least one refrigerant portion is arranged in a release position in which the release mechanism can engage with that at least one refrigerant portion to release any refrigerant contained therein, and at least one further refrigerant portion is arranged in a non-release position in which the release mechanism cannot engage with that at least one further refrigerant portion to release refrigerant contained therein.

12. A cooling system as claimed in claim 1 1 further comprising a mechanism for moving the refrigerant portions between said release and non-release positions wherein the refrigerant portion moving mechanism is configured to move a first of said refrigerant portions out of said release position and for moving a second of said refrigerant portions from a non-release position into said release position following engagement of said release mechanism with said first refrigerant portion to release refrigerant from said first refrigerant portion.

13. A cooling system as claimed in claim 12 wherein the mechanism for moving the refrigerant portions between said release and non-release positions is configured to inhibit movement of a previously used refrigerant portion from a non-release position into said release position.

14. A cooling system as claimed in claim 12 or 13 wherein the mechanism for moving the refrigerant portions between said release and non-release positions is configured to inhibit further movement of the refrigerant portions between release and non-release positions when all the refrigerant portions are exhausted.

15. A cooling system as claimed in any of claims 12 to 14 wherein the refrigerant portion moving mechanism is configured for manual operation by a user.

16. A cooling system as claimed in any of claims 12 to 14 wherein the refrigerant portion moving mechanism is configured for operation by an actuator.

17. A cooling system as claimed in any preceding claim further comprising a sound damping element arranged to dampen sound generated by vaporisation and expansion of refrigerant released from the source of pressurised refrigerant.

18. A cooling system as claimed in claim 17 wherein the sound damping element is provided as part of said release mechanism.

19. A cooling system as claimed in claim 17 or 18 wherein the sound damping element comprises at least one of a baffle and a porous material.

20. A cooling system as claimed in any preceding claim further comprising an interlock mechanism for inhibiting inadvertent activation of the release mechanism.

21. A cooling system as claimed in claim 20 wherein the interlock mechanism is configured to require a plurality of independent manual actions before the release mechanism can be activated.

22. A cooling system as claimed in any preceding claim wherein the cooling system is configured to receive a sensor input from a sensor for sensing at least one physical or physiological parameter, and to trigger operation of the system to provide a cooling effect when said sensor input indicates that the physical or physiological parameter meets at least one predetermined criterion (e.g. exceeds or falls below a predetermined threshold).

23. A cooling system as claimed in any preceding claim wherein the system is configured to receive a signal from a remote device and to trigger operation of the release mechanism responsive to receipt of said signal.

24. A cooling system as claimed in any preceding claim further comprising at least one vent for venting released refrigerant to atmosphere.

25. A cooling system as claimed in claim 24 wherein the at least one vent is arranged to vent the released refrigerant at a location and/or in a direction away from the application surface.

26. A cooling system as claimed in claim 24 or 25 wherein the at least one vent is arranged to baffle and supress the noise generated through system operation.

27. A cooling system as claimed in claim 24, 25 or 26 wherein the at least one vent is arranged to disperse the released refrigerant over a wide area.

28. A cooling system as claimed in any preceding claim wherein the receiving portion of the heat exchanger is arranged to be within a maximum distance of 2.5mm from a point at which the refrigerant leaves the source of pressurised liquid refrigerant when released, optionally within 1 mm.

29. A cooling system as claimed in any preceding claim wherein the source of pressurised liquid refrigerant is provided in a first part and the heat exchanger is provided in the second part wherein the first part and the second part are configured: for mutual engagement with one another to form an assembled device in which the heat exchanger arranged with the receiving portion positioned for receiving refrigerant when released from the refrigerant source; and

for mutual disengagement from one another to allow the second part to be separated from the first part and used, when separated, for application of the application surface of the heat exchanger to provide the localised cooling to the target area.

30. A cooling system as claimed in any claim 29 wherein the second part is configured to be a hand-held discrete device.

31. A cooling system as claimed in any of claims 1 to 29 wherein the system comprises an enclosure formed at least partially from the heat exchanger and a cover member in which the source of pressurised liquid refrigerant is housed in operation.

32. A cooling system as claimed in claim 31 wherein the cover member is configured to be opened to facilitate installation and replacement of the source of pressurised liquid refrigerant.

33. A cooling system as claimed in any claim 31 or 32 wherein the enclosure is configured to form a hand-held discrete device.