Consumable Article for a Vapour Generating Device

Abstract

A consumable article for a vapour generating device includes: a store of liquid for vaporisation in the vapour generating device; and a shape memory foam having a compressed temporary shape in which pores of the shape memory foam are closed so as to prevent passage of the liquid through and out of the shape memory foam, wherein the shape memory foam is responsive to a stimulus to change from the temporary shape to an expanded permanent shape in which the pores are open so as to allow passage of the liquid through and out of the shape memory foam for the vaporisation.

Description

FIELD OF THE INVENTION

The present invention relates to vapour generating devices, and more particularly to consumable articles for vapour generating devices.

BACKGROUND TO THE INVENTION

Vapour generating devices such as electronic cigarettes have become popular as substitutes for traditional means of tobacco consumption such as cigarettes and cigars.

Devices for vaporisation or aerosolisation typically include a heating body arranged to heat a vaporisable product from an inlet surface to an outlet surface. In operation, the vaporisable product is heated and the constituents of the product are vaporised for the consumer to inhale. In some examples, the product may comprise tobacco in a capsule or may be similar to a traditional cigarette, in other examples the product may be a liquid, or liquid contents in a capsule.

Some vapour generating devices generate a vapour or aerosol from a vaporisable liquid, for example using a heater coil which applies heat to a liquid held in a wick in order to vaporise the liquid. It is important to ensure an adequate delivery of the liquid to the wick when the device is being used by the consumer, in order to avoid “dry puffs”. On the other hand, leakage of the liquid to the wick (or elsewhere in the device) when the device is not in use is undesirable, for example because the liquid will tend not to evaporate and may therefore saturate the unheated wick.

Thus there is a need to provide a liquid storage and delivery means which can supply sufficient liquid when the device is in use yet also prevent or minimise leakage of liquid when the device is not in use. The present invention aims to address this need.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a consumable article for a vapour generating device, comprising: a store of liquid for vaporisation in the vapour generating device; and a shape memory foam having a compressed temporary shape in which pores of the shape memory foam are closed so as to prevent passage of the liquid through and out of the shape memory foam, wherein the shape memory foam is responsive to a stimulus to change from the temporary shape to an expanded permanent shape in which the pores are open so as to allow passage of the liquid through and out of the shape memory foam for said vaporisation.

As used herein, a “vapour generating device” is a device arranged to heat a vapour generating product to produce a vapour for inhalation by a consumer. A vapour generating device can also be referred to as an aerosol generating device or an electronic cigarette. In the context of the present disclosure, the terms vapour and aerosol can be used interchangeably. The vapour generating product, or aerosol generating product, can be a liquid or a combination of a liquid and a solid such as a fibrous material. The vapour generating product may also be referred to as an e-liquid. The liquid or e-liquid may comprise colourants, flavourings, tobacco, and/or other chemical components.

As used herein, the word “consumable” takes its common meaning, that is to say a disposable product which is discarded having reached its end-of-life, typically after a short period of use.

As used herein, “shape memory foam” refers to a shape memory polymer (SMP) foam capable of being deformed and having an ability to return from the deformed condition to the original shape when induced by an external stimulus. With regard to the present invention, the shape memory foam undergoes a four-step thermomechanical cycle, as follows.

In the first step, the foam is heated above its glass transition temperature (Tg) and is compressed (i.e. under an applied force to cause mechanical deformation) while at this elevated temperature. It will be understood that the glass transition temperature is the temperature at which the foam changes from a crystalline (rigid) state to an amorphous (flexible) state. The value of the glass transition temperature (Tg) will depend on the type of shape memory foam used. Thus the foam is brought into a compressed condition in which the pores of the material are substantially closed. That is, the size of the pores is in the nanometre range such to prevent the passage of a liquid through the pores. The compressed shape of the material may be referred to as a “temporary shape” and the process of heating and compressing the material may be called “programming” of the foam.

In the second step, the foam is held under strain and is allowed to cool. In the third step, the strain is removed after the material has cooled to below the glass transition temperature.

In the fourth step, the foam is exposed to a stimulus, preferably a heat stimulus to raise the temperature of the material above the glass transition temperature, to cause the material to expand so as to recover its original (uncompressed) shape.

In the expanded condition the pores of the foam are open. That is, the size of the pores is in the micrometre or millimetre range such to allow the passage of a liquid through the pores. Once expanded in this way, the foam will not tend to return to the compressed condition, unless acted upon by an external compressive force. Thus the expanded shape of the material may be referred to as a “permanent shape”.

Stimuli other than heat may be applied to trigger the recovery of the shape memory foam, for example light, magnetic field, pH, solvent, or electricity.

The shape memory capability of the foam allows for the pore size to be locked-in, either on the low nanometre-length scale or the near micrometre- or millimetre-length scale, with each state being favoured in a certain temperature range. When the shape memory foam is in the compressed condition it is substantially impermeable to the liquid, thus unwanted leakage in the inactive device is prevented. Conversely, when the shape memory foam is stimulated (e.g. heated) so as to be in the expanded condition the liquid can flow freely to the wick, ensuring that “dry puffs” are avoided in use.

The permeation of the liquid is determined by environmental conditions, i.e. the presence or absence of the stimulus which causes the porous shape memory foam to change from an OFF state in which the pores are closed to an ON state in which the pores are open. The change from the OFF state to the ON state may be substantially instantaneous or gradual, depending upon design factors such as the type and pore size of the shape memory foam, and the quantity and rate of the heat applied. Thus the wicking rate may be optimised in the design.

It is also possible to trap the liquid (or some portion of the liquid, or at least some of the components of the liquid) in a compressed shape memory foam. The trapped liquid can then be released when the foam relaxes (expands) in response to the stimulus, enabling a new type of consumable which can be conveniently inserted into a vapour generating device by a user thereof.

The shape memory foam can be manufactured in a number of ways, e.g. by gas foaming, particulate leaching, polymerized high internal phase emulsions, lyophilization, cryogellation, reticulation, or any other foaming methods known to persons skilled in the art, to obtain the final desired pore structure. Alternatively, the shape memory foam can be fabricated by coating a normal porous foam with no shape memory effects with a shape memory coating. For example, a regular PU sponge may be endowed with shape memory ability and a superlyophilic property by successively coating it with trans-1,4-polyisoprene (TPI) and lyophilic polydopamine/polyethylenimine (PDA/PEI). The wide range of available materials and the tunability of the transition temperature makes shape memory foams attractive candidates for the incorporation into e-vapour devices or consumables.

The consumable article may comprise a container which stores at least a portion of the liquid, the shape memory foam being located at an outlet of the container so that: in the compressed temporary shape the shape memory foam prevents passage of the liquid from the container; and in the expanded permanent shape the shape memory foam allows passage of the liquid from the container and through and out of the shape memory foam for said vaporisation.

A first portion (optionally a greater portion) of the liquid may be stored in the container; and a second portion (optionally a lesser portion) of the liquid may be stored within the shape memory foam when the shape memory foam is in the compressed temporary shape. Storing a portion or quantity of the liquid within the shape memory foam, when the shape memory foam is in the compressed temporary shape, may prevent the undesirable phenomenon of “dry puffs”, as will be explained in more detail later herein.

The consumable article may comprise a wick arranged to receive the liquid from the shape memory foam when the shape memory foam is in the expanded permanent shape.

The wick may be spaced from the shape memory foam when the shape memory foam is in the compressed temporary shape; and the shape memory foam may be arranged to expand into direct contact with the wick when the shape memory foam is changed from the compressed temporary shape to the expanded permanent shape, thereby to provide a path for the liquid from the container to the wick.

The wick may be arranged to be in direct contact with the shape memory foam when the shape memory foam is in the compressed temporary shape; and the shape memory foam may be arranged to expand into the container when the shape memory foam is changed from the compressed temporary shape to the expanded permanent shape, thereby to provide a path for the liquid from the container to the wick.

The shape memory foam may be partially embedded in the wick.

The consumable article may comprise a heater for vaporising the liquid received by the wick, the heater being arranged to provide a heat stimulus for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape.

The wick may be arranged to interface with a heater of the vapour generating device when the consumable article is coupled to the vapour generating device, in order to provide a heat stimulus to the shape memory foam for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape and to vaporise the liquid received by the wick.

The liquid may be stored within the shape memory foam when the shape memory foam is in the compressed temporary shape.

The consumable article may comprise a wick arranged to receive the liquid from the shape memory foam when the shape memory foam is in the expanded permanent shape.

The consumable article may comprise a heater arranged to provide a heat stimulus for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape. Optionally said heater is further arranged for vaporising the liquid received by the wick, or an additional heater is arranged for vaporising the liquid received by the wick.

The consumable article may be arranged to interface with a heater of the vapour generating device when the consumable article is coupled to the vapour generating device, in order to provide a heat stimulus to the shape memory foam for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape and to vaporise the liquid received by the wick.

The compressed shape memory foam may be configured to be insertable into the vapour generating device.

The compressed shape memory foam may contained in an expandable protective pouch, the pouch being openable so as to allow passage of the liquid to a wick of the vapour generating device when the consumable article is inserted into the vapour generating device and the shape memory foam is in the expanded permanent shape.

According to another aspect of the invention there is provided a vapour generating device comprising a consumable article as described herein above.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples will now be described, by way of example, with reference to the accompanying figures in which:

FIG. 1a shows a vapour generating device comprising a consumable article according to a first example of the invention and FIGS. 1b and 1c show details thereof;

FIGS. 2a and 2b show details of a consumable article for a vapour generating device according to a second example of the invention;

FIGS. 3a and 3b show details of a consumable article for a vapour generating device according to a third example of the invention;

FIG. 4a shows a vapour generating device comprising a consumable article according to a fourth example of the invention and FIGS. 4b and 4c show details thereof;

FIGS. 5a and 5b show details of a consumable article for a vapour generating device according to a fifth example of the invention;

FIGS. 6a and 6b show details of a consumable article for a vapour generating device according to a sixth example of the invention;

FIGS. 7a and 7b show details of a consumable article for a vapour generating device according to a seventh example of the invention; and

FIGS. 8a-c show details of a consumable article for a vapour generating device according to an eighth example of the invention.

DETAILED DESCRIPTION

Referring to FIGS. 1a and 1b, in a first example a vapour generating device 10 comprises a reusable part 12 and a consumable part 14 which is connected or coupled to the reusable part 12. The reusable part 12 comprises a power source, (e.g. a battery) 12a, a controller 12b, and a through-channel 12c which is open to the environment so that ambient air can flow along the through-channel 12c (as indicated by the arrow).

The consumable part 14 comprises a tubular body having a bore which extends along a central longitudinal axis Z of the tubular body. In this example, the tubular body is constructed from plastics. An upper part of the tubular body comprises a mouthpiece configured for engagement with the mouth of a consumer or user of the device. A disc-shaped wick 16 is located at a lower part of the tubular body and extends across the bore in a transverse direction, i.e. substantially normal to the longitudinal axis Z. The wick is constructed from conventional materials, for example cotton or ceramic.

A storage reservoir or tank 18 containing an e-liquid L is formed within the wall of the tubular body. A shape memory foam 20 is located between the tank 18 and the wick 16. In this example, the shape memory foam 20 is ring-shaped and comprises an outer side surface which is in abutment with an outlet of the tank 18 and an inner side surface which is in abutment with the wick 16. The shape memory foam 20 is in a temporary shape, as has been described herein above. Thus the shape memory foam 20 is in a compressed condition so that pores of the shape memory foam 20 are substantially closed. Accordingly the shape memory foam 20 prevents or at least resists egress of the e-liquid L from the outlet of the tank 18. That is, the shape memory foam 20 seals the e-liquid L in the tank 18. In other words, the shape memory foam 20 acts as an e-liquid L retention material.

A metallic heater coil 22 extends around the wick 20 and is connected to the power source 21a. The heater coil 22 is operable to vaporise the e-liquid L when the e-liquid L is held by the wick 16. The bore defines a flow channel for flow of the vapour from the wick 16 to the mouthpiece for inhalation of the vapour by the user (as indicated by the arrow).

Referring now to FIG. 1c, in operation the heater coil 22 is activated, either automatically or manually, to cause the wick 16 to be heated. Heat from the wick 16 is transferred (conducted) to the shape memory foam 20. This heat stimulus causes the temperature of the shape memory foam 20 to be raised above the glass transition temperature, as has been described herein above. Accordingly the shape memory foam 20 expands so as to recover its original (uncompressed) shape. The direction of expansion of the shape memory foam 20 is into the tank 18 containing the e-liquid L (i.e. to the right in the sense of FIG. 1c), since the shape memory foam 20 is generally constrained from expansion in other directions by the wick 16 and the surrounding structure of the consumable part 14. The structure may comprise a solid wall which will not allow the passage of e-liquid L. Alternatively the structure may comprise a wall including perforations or apertures which will allow e-liquid to pass through while still preventing the shape memory foam 20 from expanding toward the wall.

Thus the pores of the shape memory foam 20 are opened and the shape memory foam 20 is in its expanded “permanent shape”. As a result, the e-liquid L flows or permeates from the tank 18 into the pores of the shape memory foam 20 at the outer side surface thereof by means of capillary action (as indicated by the arrow in FIG. 1c). The e-liquid L progresses through the shape memory foam 20 to the inner side surface thereof and is received by the wick 16 by means of capillary action. Thus the hot wick 16 absorbs and vaporises the e-liquid L for inhalation by the user.

It will therefore be understood that the shape memory foam 20 has an OFF state, i.e. when the material is compressed such as to block flow or prevent permeation of the e-liquid L from the tank 18, and an ON state, i.e. when the material is expanded such as to allow flow or permeation of the e-liquid L from the tank 18. Furthermore the duration of the transition from the OFF state to the ON state can be predetermined, for example by carefully selecting the type and pore size of the shape memory foam 20 and by controlling the quantity and rate of the heat applied. In this way it is possible to control the rate at which the e-liquid L passes through the shape memory foam 20 and the wick 16. In other words, the wicking rate can be controlled.

The shape memory foam 20 itself acts a wick when expanded, i.e. by means of capillary action. Thus the expanded shape memory foam 20 can be thought of as a second wick, or as an extension of the first wick 16 that is in engagement with the heater coil 22. Together the first wick 16 and the shape memory foam 20 may be thought of as a composite wick. It may be advantageous to make the shape memory foam 20 relatively narrow and the wick 16 relatively wide, in order to save cost on the more expensive shape memory foam material.

Turning now to FIGS. 2a and 2b, a second example of the invention differs from the above-described first example in that there is provided a lateral gap G (see FIG. 2a) between the wick 16 and the inner side surface of the shape memory foam 20. The gap G prevents fluid communication between the e-liquid L and the wick 16 when the shape memory foam 20 is in the OFF state. This is advantageous in the event that some quantity of the e-liquid L escapes through or around the shape memory foam 20 when in the OFF state, for example due to accidental damage to the shape memory foam 20 or the tank 18, or due to capillary action over a long period of time.

The gap G is carefully sized, such as to be large enough to prevent fluid communication between the e-liquid L and the wick 16 (see FIG. 2a), and small enough to allow heat transfer from the heated wick 16 to the shape memory foam 20 and also for the shape memory foam 20 to bridge the gap to reach the wick 16 when expanded (see FIG. 2b). It will be understood that the heat produced by the heater coil 22 is transferred from the wick 16 to the shape memory foam 20 via the connecting structure of the consumable part 14 as well as the air in the gap G.

This example also comprises a rigid mesh or grid 24 located at the outlet of the tank 18 and in contact with the e-liquid L. The mesh 24 constrains the shape memory foam 20 such that expansion of the activated shape memory foam 20 is toward the wick 16 (to the left in the sense of FIG. 2b). Of course the e-liquid L is able to flow through the mesh 22 in order to enter the expanded pores of the shape memory foam 20.

Referring next to FIGS. 3a and 3b, a third example of the invention differs from the above-described first and second examples in that the shape memory foam 20 is made comparatively more shallow so as to be partially embedded in the wick 16. Thus portions of the upper and lower surfaces as well as the inner side surface of the shape memory foam 20 are in contact with the wick 16. The greater surface areas in contact with each other are advantageous in that they allow a more rapid transfer of heat from the wick 16 to the shape memory foam 20 when the heater coil 22 is activated.

The more shallow form of the shape memory foam 20 also means that the outer side surface of the shape memory foam 20, which is in contact with the e-liquid L, has a smaller surface area in comparison to the first and second examples. This is advantageous with respect to the rapid transfer of heat from the wick 16 to the shape memory foam 20 because less heat will be lost to the e-liquid L (which has a large thermal mass) through the shape memory foam 20.

Similar to the first example, in this third example the direction of expansion of the shape memory foam 20 is into the tank 18 containing the e-liquid L (i.e. to the right in the sense of FIG. 3b), since the shape memory foam 20 is generally constrained from expansion in other directions by the wick 16 and the surrounding structure of the consumable part 14.

In each of the first, second and third examples described herein above, the interface between the wick 16 and the inner side surface of the shape memory foam 20 is configured so that the temperature at the inner side surface does not exceed the melting/degradation temperature of the shape memory foam 20.

While in each of the three examples described herein above a metallic heater coil 22 is provided in the consumable part 14 of the vapour generating device 10, in other examples a heating means is provided in a reusable part of such a device, as follows.

Referring to FIGS. 4a and 4b, in a fourth example a vapour generating device 10 comprises a reusable part 12′ and a consumable part 14′ which is connectable to the reusable part 12′. The reusable part 12′ comprises a power source (e.g. a battery) 12a′, a controller 12b′, and a heater element 22′.

The consumable part 14′ comprises a tubular body having a bore which extends along a central longitudinal axis Z of the tubular body. In this example, the tubular body is constructed from plastics. An upper part of the tubular body comprises a mouthpiece configured for engagement with the mouth of a consumer or user of the device. A through-channel 14a is open to the environment so that ambient air can flow along the through-channel 14a to the bore (as indicated by the arrows).

A disc-shaped wick 16′ is located at a lower part of the tubular body and extends across the bore in a transverse direction, i.e. substantially normal to the longitudinal axis Z. In this example the wick is constructed from a temperature-resistant ceramic material. The wick may alternatively be constructed from cotton.

A storage reservoir or tank 18′ containing an e-liquid L is formed within the wall of the tubular body. A shape memory foam 20′ is located between an outlet of the tank 18′ and the wick 16′. In this example, the shape memory foam 20′ is ring-shaped. Each of an outer side surface and an upper surface of the shape memory foam 20′ is located in the tank 18′ so as to be in contact with the e-liquid L therein. A radially-inner portion of the lower surface of the shape memory foam 20′ is in abutment with the upper surface of the wick 16′, while a radially-outer portion of said lower surface is in abutment with the structure of the consumable part 14′ which forms the base of the tank 18′.

Still referring to FIGS. 4a and 4b, the shape memory foam 20′ is in a temporary shape, as has been described herein above. Thus the shape memory foam 20′ is in a compressed condition so that pores of the shape memory foam 20′ are substantially closed. Accordingly the shape memory foam 20′ prevents or at least resists egress of the e-liquid L from the tank 18′. In other words, the shape memory foam 20′ seals the e-liquid L in the tank 18′.

When the consumable part 14′ is connected or coupled to the reusable part 12′, the upper surface of the heater element 22′ is brought into abutment with the lower surface of the wick 16′. In this condition the heater element 22′ is operable to vaporise the e-liquid L when the e-liquid L is held by the wick 16′. The bore defines a flow channel for flow of the vapour from the wick 16′ to the mouthpiece for inhalation by the user (as indicated by the arrow).

Referring now to FIG. 4c, in operation the heater element 22′ is activated, either automatically or manually, to cause the wick 16′ to be heated. Heat from the wick 16′ is transferred (conducted) to the shape memory foam 20′. This heat stimulus causes the temperature of the shape memory foam 20′ to be raised above the glass transition temperature, as has been described herein above. Accordingly the shape memory foam 20′ expands so as to recover its original (uncompressed) shape. The direction of expansion of the shape memory foam 20′ is into the tank 18′ containing the e-liquid L (i.e. to the left and right and upward in the sense of FIG. 4a), the shape memory foam 20′ being constrained from expansion toward the wick 16′ by the wick 16′ itself.

Thus the pores of the shape memory foam 20′ are opened and the shape memory foam 20′ is in its expanded “permanent shape”. As a result, the e-liquid L flows or permeates from the tank 18′ into the pores of the shape memory foam 20′ at the outer side surface and the upper surface thereof by means of capillary action. The e-liquid L progresses through the shape memory foam 20′ to the radially-inner portion of the lower surface thereof and is received by the wick 16′ by means of capillary action. Thus the hot wick 16′ absorbs and vaporises the e-liquid L for inhalation by the user.

It will therefore be understood that the shape memory foam 20′ has an OFF state, i.e. when the material is compressed such as to block flow or prevent permeation of the e-liquid L from the tank 18′, and an ON state, i.e. when the material is expanded such as to allow flow or permeation of the e-liquid L from the tank 18′.

Furthermore the duration of the transition from the OFF state to the ON state can be predetermined, for example by carefully selecting the type and pore size of the shape memory foam 20′ and by controlling the quantity and rate of the heat applied. In this way it is possible to control the rate at which the e-liquid L passes through the shape memory foam 20′ and the wick 16′. In other words, the wicking rate can be controlled.

The shape memory foam 20′ itself acts a wick when expanded, i.e. by means of capillary action. Thus the expanded shape memory foam 20′ can be thought of as a second wick, or as an extension of the first wick 16′ that is in engagement with the heater element 22′. Together the first wick 16′ and the shape memory foam 20′ may be thought of as a composite wick. Furthermore the composite wick may be described as being a vertically-stacked composite wick.

In this fourth example, the ceramic material of the wick 16′ should be made thin enough to allow the shape memory foam 20′ to achieve a temperature above the glass transition temperature of the shape memory foam 20′, but not so high as to cause thermal degradation thereof. The wick 16′ should be between 0.5 mm and 10 mm thick. The lower surface of the wick 16′ may comprise a plurality of surface structures or projections 16′a (see FIGS. 4b and 4c) for contact with the heater element 22′. This allows for air and vapour flow control and also further control of wicking rate. The density of these structures can also be used to control the rate of heat transfer through the wick 16′ to the shape memory foam 20′. The contact surface percentage of the wick 16′ to the heater element 22′ should preferably be between 25% and 80%.

In each of the first, second, third and fourth examples described herein above, heat is transferred (conducted) from the wick 16, 16′ to the shape memory foam 20, 20′ when the heater coil 22/heater element 22′ is activated. There is a risk that the user might initially experience a “dry puff”, since the dry shape memory foam 20, 20′ (and the dry wick 16, 16′) is a relatively poor conductor of heat and so the e-liquid might not reach the wick 16, 16′ at the first puff. This may be overcome by providing a quantity of e-liquid L within the compressed shape memory foam 20, 20′ itself, in addition to the e-liquid in the separate reservoir or tank.

This is achieved by wetting (e.g. fully or partially saturating) the shape memory foam 20, 20′ with the e-liquid, prior to carrying out the first step (heating and compression) of the four-step thermomechanical cycle described herein above. Thus a quantity or portion of e-liquid L is trapped in the shape memory foam 20, 20′ when the shape memory foam 20′ is in the compressed condition.

The trapped e-liquid L will act as a thermal bridge (i.e. improving heat conduction) and ensure the entire shape memory foam 20, 20′ (along with the wick 16, 16′) is heated rapidly and evenly. In this way, it is possible to avoid potential dry puffs during the first use of the device, while still preventing escape of e-liquid before use since the pores of the shape memory foam 20, 20′ will still be too small for any flow prior to heater activation.

Turning now to FIG. 5a, a fifth example of the invention differs from the above-described fourth example, in that the e-liquid L is provided within the compressed shape memory foam 20′ itself, rather than in a separate reservoir or tank. This is achieved by wetting (e.g. saturating) the shape memory foam 20′ with the e-liquid, prior to carrying out the first step (heating and compression) of the four-step thermomechanical cycle described herein above. Thus the e-liquid L is trapped in the shape memory foam 20′ when the shape memory foam 20′ is in the compressed condition. In other words, the compressed shape memory foam 20′ is loaded with the e-liquid L.

Referring to FIG. 5b, in operation the heater element 22′ is activated, either automatically or manually, to cause the wick 16′ to be heated. Heat from the wick 16′ is transferred (conducted) to the shape memory foam 20′ and the e-liquid contained therein. This heat stimulus causes the temperature of the shape memory foam 20′ to be raised above the glass transition temperature, as has been described herein above. Accordingly the shape memory foam 20′ expands so as to recover its original (uncompressed) shape. The direction of expansion of the shape memory foam 20′ is away from the wick 16′ (i.e. upward in the sense of FIG. 5b), the shape memory foam 20′ being constrained from radial expansion by the walls of the tubular body.

Thus the pores of the shape memory foam 20′ are opened and the shape memory foam 20′ is in its expanded “permanent shape”. As a result, the e-liquid L flows or permeates from the external surfaces of the shape memory foam 20′ and is received by the wick 16′ by means of capillary action. Thus the hot wick 16′ absorbs and vaporises the e-liquid L for inhalation by the user.

Turning now to FIG. 6a, a sixth example of the invention differs from the above-described fifth example, in that the consumable part 14′ comprises one or more heaters 26 for heating the shape memory foam 20′ above the glass transition temperature. In this example the heaters 26 are provided in the wall of the tubular body such as to form a heated compartment or chamber for holding the shape memory foam 20′. The heaters 26 are connectable to the power source 12a′ in the reusable part 12′.

Referring to FIG. 6b, the heaters 26 may be used alone to heat the shape memory foam 20′ above the glass transition temperature, or in conjunction with the heater element 22′, in order to expand the shape memory foam 20′ as has been described herein above.

Turning now to FIG. 7a, a seventh example of the invention differs from the above-described fifth and sixth examples, in that the compressed shape memory foam 20′ which is pre-loaded with the e-liquid L is a distinct element that is provided separately from the other parts of the vapour generating device 10′. In this example, the compressed shape memory foam 20′ is sized and configured to be received in the tubular body (as indicated by the arrow in FIG. 7a). The compressed shape memory foam 20′ may be inserted into the vapour generating device 10′ by the user of the device 10′. Thus the compressed shape memory foam 20′ may be referred to as an insert for the vapour generating device 10′.

Referring also to FIG. 7b, the compressed shape memory foam 20′ is inserted into the tubular body and is heated, in the manner described herein above with respect to the fifth or sixth example, in order to expand the shape memory foam 20′ as has been described.

Turning now to FIG. 8a, an eighth example of the invention differs from the above-described seventh example, in that the compressed shape memory foam 20′ which is pre-loaded with the e-liquid L (i.e. the insert) comprises an outer pouch 28 which generally covers or encapsulates the compressed shape memory foam 20′. The pouch 28 provides a protective layer for the compressed shape memory foam 20′ and prevents the e-liquid L from leaking from the compressed shape memory foam 20′, for example if the compressed shape memory foam 20′ is inadvertently exposed to heat or is left in storage for a long period of time.

Referring also to FIG. 8b, a portion of the pouch 28 is removed (e.g. cut, pierced, or peeled away) from the lower surface of the compressed shape memory foam 20′ and the pouch 28 is inserted into the tubular body so that said lower surface is brought into abutment with the wick 16′. Referring next to FIG. 8c, the pouch 28 is heated in order to expand the shape memory foam 20′ as has been described herein above. The pouch 28 is constructed from an elastic material in order to accommodate the expansion of the activated shape memory foam 20′ within the pouch. The absence of said removed portion of the pouch 28 at the lower surface of the compressed shape memory foam 20′ allows for the e-liquid L which is released from the compressed shape memory foam 20′ to be received by the wick 16′.

In each of the fourth, fifth, sixth, seventh and eighth examples described herein above, the consumable part 14′ may comprise a thermal interface material at the lower surface of the wick 16′. Thus when the consumable part 14′ is coupled to the reusable part 12′, the thermal interface material will be located between and in abutment with the wick 16′ and the heater element 22′.

With regard to each of the above-described examples, the glass transition temperature (Tg) of the shape memory foam is preferably between about 30° C. and 90° C., more preferably between about 40° C. and 70° C., and most preferably between about 50° C. and 60° C. If the glass transition temperature is too low, the transition may be triggered prematurely during storage in a hot environment. If it is too high, a longer heat-up time will become necessary and the energy efficiency will be reduced.

With regard to each of the fifth, sixth, seventh and eighth examples described herein above, it will be understood that “pre-loading” of the shape memory foam 20′ with e-liquid L is beneficial for efficient heat conduction and can help to avoid the risk of “dry puffs”, as has been described herein above in connection with the first, second, third and fourth examples.

It should be understood that the invention has been described in relation to its preferred embodiments and may be modified in many different ways without departing from the scope of the invention as defined by the accompanying claims.

Claims

1. A consumable article for a vapour generating device, comprising: a store of liquid for vaporisation in the vapour generating device; anda shape memory foam having a compressed temporary shape in which pores of the shape memory foam are closed so as to prevent passage of the liquid through and out of the shape memory foam,wherein the shape memory foam is responsive to a stimulus to change from the compressed temporary shape to an expanded permanent shape in which the pores are open so as to allow passage of the liquid through and out of the shape memory foam for said vaporisation.

2. The consumable article according to claim 1, further comprising a container which stores at least a portion of the liquid, the shape memory foam being located at an outlet of the container so that: in the compressed temporary shape the shape memory foam prevents passage of the liquid from the container; andin the expanded permanent shape the shape memory foam allows passage of the liquid from the container and through and out of the shape memory foam for said vaporisation.

3. The consumable article according to claim 2, wherein: a first portion of the liquid is stored in the container; anda second portion of the liquid is stored within the shape memory foam when the shape memory foam is in the compressed temporary shape.

4. The consumable article according to claim 2, further comprising a wick arranged to receive the liquid from the shape memory foam-when the shape memory foam is in the expanded permanent shape.

5. The consumable article according to claim 2, wherein: the wick is spaced from the shape memory foam when the shape memory foam is in the compressed temporary shape; andthe shape memory foam is arranged to expand into direct contact with the wick when the shape memory foam is changed from the compressed temporary shape to the expanded permanent shape,thereby to provide a path for the liquid from the container to the wick.

6. The consumable article according to claim 4, wherein: the wick is arranged to be in direct contact with the shape memory foam when the shape memory foam is in the compressed temporary shape; andthe shape memory foam is arranged to expand into the container when the shape memory foam is changed from the compressed temporary shape to the expanded permanent shape,thereby to provide a path for the liquid from the container to the wick.

7. The consumable article according to claim 6, wherein the shape memory foam is partially embedded in the wick.

8. The consumable article according to claim 4, further comprising a heater for vaporising the liquid received by the wick, the heater being arranged to provide a heat stimulus for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape.

9. The consumable article according to claim 4, wherein the wick is arranged to interface with a heater of the vapour generating device when the consumable article is coupled to the vapour generating device, in order to provide a heat stimulus to the shape memory foam for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape and to vaporise the liquid received by the wick.

10. A The consumable article according to claim 1, wherein the liquid is stored within the shape memory foam when the shape memory foam is in the compressed temporary shape.

11. A The consumable article according to claim 10, further comprising a wick arranged to receive the liquid from the shape memory foam when the shape memory foam is in the expanded permanent shape.

12. A The consumable article according to claim 11, further comprising a heater arranged to provide a heat stimulus for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape.

13. The consumable article according to claim 11, wherein the wick is arranged to interface with a heater of the vapour generating device-when the consumable article is coupled to the vapour generating device, in order to provide a heat stimulus to the shape memory foam for said change of the shape memory foam from the compressed temporary shape to the expanded permanent shape and to vaporise the liquid received by the wick.

14. The consumable article according to claim 10, wherein the shape memory foam in the compressed temporary shape is configured to be insertable into the vapour generating device.

15. A vapour generating device comprising the consumable article according to claim 1.

16. The consumable article according to claim 12, wherein said heater is further arranged for vaporising the liquid received by the wick.

17. The consumable article according to claim 12, wherein an additional heater is arranged for vaporising the liquid received by the wick.

18. The consumable article according to claim 14, wherein the shape memory foam in the compressed temporary shape is contained in an expandable protective pouch, the pouch being openable so as to allow passage of the liquid to a wick of the vapour generating device when the consumable article is inserted into the vapour generating device and the shape memory foam is in the expanded permanent shape.