Atomiser assembly with dry-out protection

Abstract

An atomiser assembly for a vapour provision system comprises a heating element for vaporising aerosol-generating substrate; a porous member for delivering aerosol-generating substrate to the heating element; and a shape memory alloy component changeable from a first shape which maintains the heating element and the porous member in a first spatial relationship, to a second shape which places the heating element and the porous member in a second spatial relationship in which the heating element and the porous member have a greater separation than in the first spatial relationship, the second shape being assumed when the shape memory alloy component is heated to a threshold temperature.

Description

[0001] ATOMISER ASSEMBLY WITH DRY-OUT PROTECTION

[0002] Technical Field

[0003] The present disclosure relates to an atomiser assembly for a vapour provision system having dry-out protection, and components and vapour provision systems comprising such an atomiser assembly.

[0004] Background

[0005] Many electronic vapour provision systems, such as e-cigarettes and other electronic nicotine delivery systems that deliver nicotine via vaporised liquids, utilise an atomiser to generate vapour. In some systems, the atomiser comprises a heater in the form of one or more electrical heating elements which apply heat to an aerosolisable substrate material (typically in liquid form) in order to vaporise the liquid. The resulting vapour is entrained into a flow of air through the system which is produced by the user drawing air into the system by inhalation, to create an aerosol for delivery to the user through an aerosol outlet at the mouthpiece of the system. The aerosolisable substrate material is stored in a reservoir, and delivered to the heater to be vaporised. The delivery can be achieved by a porous member of which one or more parts extend into the reservoir and one or more other parts are in contact with or close to the heater. The porous member absorbs aerosolisable substrate material out of the reservoir, and transfers the aerosolisable substrate material by capillary action towards the heater, where the aerosolisable substrate material absorbs heat energy produced by the heater and is vaporised.

[0006] Under normal operation of the vapour provision system, the porous member transfers aerosolisable substrate material to the heater at an appropriate rate to replace the aerosolisable substrate material which has been removed by vaporisation, and an equilibrium exists. An appropriate amount of electrical power is applied to the heater to maintain the heater at a correct temperature for vaporisation, according to factors including the type of aerosolisable substrate material and the amount of vapour desired by the user; and heat energy from the heater is transferred to the aerosolisable substrate material held in the porous member.

[0007] However, if the supply of aerosolisable substrate material to the atomiser diminishes or fails, the heater can overheat. This can occur when the reservoir becomes empty, or a if a blockage or malfunction arises in the liquid pathway between the reservoir and the heater, or of the user puffs strongly or rapidly so that the production of vapour outstrips the capillary supply of new substrate, for example. When there is insufficient aerosolisable substrate material present in the porous member to take up the heat energy output by the heater, the electrical power supplied to the heater is instead utilised only to heat the heater, and the heater temperature will increase above its normal operating temperature. The close proximity of the heater to the porous member means that the porous member, now drying out due to a shortage of substrate, also becomes overheated, and can become scorched or burnt. This is particularly an issue for porous members susceptible to excess heat exposure, such a porous members made from materials such as cotton. The heat exposure can damage the porous member for subsequent use of the vapour provision system, and also may cause the vapour provision system to emit a burnt taste and / or a smell of burning, giving a poor experience for the user.

[0008] Existing solutions for protecting a vapour provision system from this problem, which is know as “dry-out”, include monitoring the liquid level in the reservoir or the temperature at the heater, and disabling the heater (by preventing the continued supply of electrical power) when it is detected that the reservoir is becoming or has become empty, or the heater is becoming too hot. However, this typically requires a dedicated sensor, uses more electrical power and therefore is a drain on the battery of the vapour provision system, and can be liable to inaccuracies.

[0009] Accordingly, alternative approaches to protecting atomisers in the event of dry-out are of interest.

[0010] Summary

[0011] According to a first aspect of some embodiments described herein, there is provided an atomiser assembly for a vapour provision system comprising: a heating element for vaporising aerosol-generating substrate; a porous member for delivering aerosol-generating substrate to the heating element; and a shape memory alloy component changeable from a first shape which maintains the heating element and the porous member in a first spatial relationship, to a second shape which places the heating element and the porous member in a second spatial relationship in which the heating element and the porous member have a greater separation than in the first spatial relationship, the second shape being assumed when the shape memory alloy component is heated to a threshold temperature.

[0012] According to a second aspect of some embodiments described herein, there is provided a component for a vapour provision system, the component comprising an atomiser assembly according to the first aspect.

[0013] According to a third aspect of some embodiments described herein, there is provided a vapour provision system comprising an atomiser assembly according to the first aspect or a component according to the second aspect.

[0014] According to a fourth aspect of some embodiments described herein, there is provided an atomiser assembly for a vapour provision system comprising: a heating element for vaporising aerosol-generating substrate; a porous member for delivering aerosolgenerating substrate to the heating element; and a shape memory polymer component changeable from a first shape which maintains the heating element and the porous member in a first spatial relationship, to a second shape which places the heating element and the porous member in a second spatial relationship in which the heating element and the porous member have a greater separation than in the first spatial relationship, the second shape being assumed when the shape memory polymer component is heated to a threshold temperature.

[0015] These and further aspects of the certain embodiments are set out in the appended independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with each other and features of the independent claims in combinations other than those explicitly set out in the claims. Furthermore, the approach described herein is not restricted to specific embodiments such as set out below, but includes and contemplates any appropriate combinations of features presented herein. For example, an atomiser assembly, and a component or vapour provision system comprising an atomiser assembly may be provided in accordance with approaches described herein which includes any one or more of the various features described below as appropriate.

[0016] Brief Description of the Drawings

[0017] Various embodiments of the invention will now be described in detail by way of example only with reference to the following drawings in which:

[0018] Figure 1 shows a simplified schematic longitudinal cross-section through an example vapour provision system to which aspects of the disclosure can be applied;

[0019] Figure 2 shows a temperature scale indicating a temperature regime suitable for implementation in examples of atomiser assemblies according to the present disclosure;

[0020] Figure 3A shows a simplified schematic side view of a first example atomiser assembly according to an aspect of the present disclosure, in a first spatial relationship;

[0021] Figures 3B, 3C and 3D show the atomiser assembly of Figure 3A arranged in a second spatial relationship according to different alternatives;

[0022] Figure 4A shows a simplified schematic side view of a second example atomiser assembly according to an aspect of the present disclosure, including a substrate;

[0023] Figure 4B shows a simplified schematic side view of a third example atomiser assembly according to an aspect of the present disclosure, including a substrate;

[0024] Figure 5 shows a simplified schematic side view of a fourth example atomiser assembly according to an aspect of the present disclosure, in a second spatial relationship;

[0025] Figure 6 shows a simplified perspective view of a fifth example atomiser assembly according to an aspect of the present disclosure;

[0026] Figures 7A-7D show simplified schematic side views of various examples of shape memory alloy components suitable for use in atomiser assemblies such as those of the first to fifth examples, in first and second shapes; Figures 8A and 8B show simplified schematic side views of a sixth example atomiser assembly according to an aspect of the present disclosure, in a first spatial relationship and a second spatial relationship;

[0027] Figure 9 shows a simplified perspective view of a seventh example atomiser assembly according to an aspect of the present disclosure;

[0028] Figure 10 shows a simplified end view of the atomiser assembly of Figure 9, with a heating element configured according to an example, in a first and a second spatial relationship; and

[0029] Figure 11 shows a perspective view of a further example heating element suitable for use in the atomiser assembly of Figure 10.

[0030] Detailed Description

[0031] Aspects and features of certain examples and embodiments are discussed I described herein. Some aspects and features of certain examples and embodiments may be implemented conventionally and these are not discussed I described in detail in the interests of brevity. It will thus be appreciated that aspects and features of apparatus discussed herein which are not described in detail may be implemented in accordance with any conventional techniques for implementing such aspects and features.

[0032] As described above, the present disclosure relates to electronic aerosol or vapour provision systems, such as e-cigarettes. Throughout the following description the terms “e- cigarette” and “electronic cigarette” may sometimes be used; however, it will be appreciated these terms may be used interchangeably with aerosol (vapour) provision system or device. The systems are intended to generate an inhalable aerosol by vaporisation of an aerosolforming substrate in the form of a liquid or gel which may or may not contain nicotine. Additionally, hybrid systems may comprise a liquid or gel substrate plus a solid substrate which is also heated. The solid substrate may be for example tobacco or other non-tobacco products, which may or may not contain nicotine. The term “aerosolisable substrate material” as used herein is intended to refer to substrate materials which can form an aerosol, either through the application of heat or some other means. The term “aerosol” may be used interchangeably with “vapour”.

[0033] As used herein, the term “component” is used to refer to a part, section, unit, module, assembly or similar of an electronic cigarette or similar device that incorporates several smaller parts or elements, possibly within an exterior housing or wall. An electronic cigarette may be formed or built from one or more such components, and the components may be removably or separably connectable to one another, or may be permanently joined together during manufacture to define the whole electronic cigarette. The present disclosure is applicable to (but not limited to) systems comprising two components separably connectable to one another and configured, for example, as an aerosolisable substrate material carrying component holding liquid or another aerosolisable substrate material (a cartridge, cartomiser or consumable), and a control unit or device component having a battery for providing electrical power to operate an element for generating vapour from the substrate material. For the sake of providing a concrete example, in the present disclosure, a cartridge or cartomiser is described as an example of the aerosolisable substrate material carrying portion or component, but the disclosure is not limited in this regard and is applicable to any configuration of aerosolisable substrate material carrying portion or component. Also, such a component may include more or fewer parts than those included in the examples.

[0034] The present disclosure is relevant to vapour provision systems and components thereof that utilise aerosolisable substrate material in the form of a liquid or a gel which is held in a reservoir, tank, container or other receptacle comprised in the system. An arrangement for delivering the substrate material from the reservoir for the purpose of providing it for vapour I aerosol generation is included. The terms “liquid”, “gel”, “fluid”, “source liquid”, “source gel”, “source fluid” and the like may be used interchangeably with “aerosolisable substrate material” and “substrate material” to refer to aerosolisable substrate material that has a form capable of being stored and delivered in accordance with examples of the present disclosure.

[0035] Figure 1 is a highly schematic diagram (not to scale) of a generic example aerosol / vapour provision system such as an e-cigarette 10, presented for the purpose of showing the relationship between the various parts of a typical system and explaining the general principles of operation. The e-cigarette 10 has a generally elongate shape in this example, extending along a longitudinal axis indicated by a dashed line, and comprises two main components, namely a control or power component, section or unit 20, and a cartridge assembly or section 30 (sometimes referred to as a cartomiser or clearomiser) carrying aerosolisable substrate material and operating as a vapour-generating component.

[0036] The cartomiser 30 includes a reservoir 3 containing a source liquid or other aerosolisable substrate material comprising a formulation such as liquid or gel from which an aerosol is to be generated, for example containing nicotine. As an example, the source liquid may comprise around 1 to 3% nicotine and 50% glycerol, with the remainder comprising roughly equal measures of water and propylene glycol, and possibly also comprising other components, such as flavourings. Nicotine-free source liquid may also be used, such as to deliver flavouring. A solid substrate (not illustrated), such as a portion of tobacco or other flavour element through which vapour generated from the liquid is passed, may also be included. The reservoir 3 has the form of a storage tank, being a container or receptacle in which source liquid can be stored such that the liquid is free to move and flow within the confines of the tank. For a consumable cartomiser, the reservoir 3 may be sealed after filling during manufacture so as to be disposable after the source liquid is consumed, otherwise, it may have an inlet port or other opening through which new source liquid can be added by the user. The cartomiser 30 also comprises an electrically powered heating element or heater 4 located externally of the reservoir tank 3 for generating the aerosol by vaporisation of the source liquid by heating. Of relevance to the current disclosure a liquid transfer or delivery arrangement (liquid transport element) such as a wick or other porous element or member 6 is provided to deliver source liquid from the reservoir 3 to the heater 4. A wick 6 may have one or more parts located inside the reservoir 3, or otherwise be in fluid communication with the liquid in the reservoir 3, so as to be able to absorb source liquid and transfer it by wicking or capillary action to other parts of the wick 6 that are adjacent or in contact with the heater 4. This liquid is thereby heated and vaporised, to be replaced by new source liquid from the reservoir for transfer to the heater 4 by the wick 6. The wick may be thought of as a bridge, path or conduit between the reservoir 3 and the heater 4 that delivers or transfers liquid from the reservoir to the heater. Terms including conduit, liquid conduit, liquid transfer path, liquid delivery path, liquid transfer mechanism or element, and liquid delivery mechanism or element may be used to in this context, but in the context of the present disclose a porous member is used, which is formed from a material susceptible to heat damage, of which cotton is an example (other materials are not excluded). For convenience herein the term “wick” may be used interchangeably with “porous member” or “porous element”.

[0037] A heater and wick (or similar) combination is sometimes referred to as an atomiser or atomiser assembly, and the reservoir with its source liquid plus the atomiser may be collectively referred to as an aerosol source. Other terminology may include a liquid delivery assembly or a liquid transfer assembly, where in the present context these terms may be used interchangeably to refer to a vapour-generating element (vapour generator) plus a wicking or similar component or structure (porous member) that delivers or transfers liquid obtained from a reservoir to the vapour generator for vapour I aerosol generation. Various designs are possible, in which the parts may be differently arranged compared with the highly schematic representation of Figure 1. In general, an atomiser can be considered as one or more elements that implement the functionality of a vapour-generating or vaporising element able to generate vapour from source liquid delivered to it, and a liquid transport or delivery element able to deliver or transport liquid from a reservoir or similar liquid store to the vapour generator by a wicking action I capillary force. In the present context, however, an atomiser comprises a wick 6 which is a distinct part or structure different from the heater or heating element 4, and arranged in contact with or in close proximity to the heater 4. In an electrical or electronic device, the vapour generating element may be an electrical heating element that operates by ohmic / resistive (Joule) heating or by inductive heating. An atomiser is typically but not essentially housed in a cartomiser component of a vapour generating system. Embodiments of the disclosure are applicable to all and any such configurations which are consistent with the examples and description herein.

[0038] Returning to Figure 1 , the cartomiser 30 also includes a mouthpiece or mouthpiece portion 35 having an opening or aerosol outlet through which a user may inhale the aerosol generated by the atomiser 4.

[0039] The power component or control unit or, simply, device or device component 20 includes a cell or battery 5 (referred to herein after as a battery, and which may be rechargeable) to provide power for electrical components of the e-cigarette 10, in particular to operate the heater 4. Additionally, there is a controller 28 such as a printed circuit board and / or other electronics or circuitry for generally controlling the e-cigarette. The control electronics / circuitry 28 operates the heater 4 using power from the battery 5 when vapour is required, for example in response to a signal from an air pressure sensor or air flow sensor (not shown) that detects an inhalation on the system 10 during which air A enters through one or more air inlets 26 in the wall of the control unit 20. When the heating element 4 is operated, the heating element 4 vaporises source liquid delivered from the reservoir 3 by the liquid delivery element 6 to generate the aerosol, and this is then inhaled by a user through the opening in the mouthpiece 35. The aerosol is carried from the aerosol source to the mouthpiece 35 along one or more air flow channels (not shown) that connect the air inlet(s) 26 to the aerosol source to the aerosol outlet when a user inhales on the mouthpiece 35. Since in this example the air inlets 26 to the system are located in the device component 20, the cartomiser 30 has its own air inlet(s) in air flow communication with the device component 20 so that air drawn in through the device air inlet(s) 26 can reach the interior of the cartomiser 30, and the atomiser. In other designs, air inlets may be located in the outer wall of the cartomiser 30 so that air enters directly into the cartomiser 30 instead of arriving there via the device component 20.

[0040] The device component (control unit) 20 and the cartomiser (cartridge assembly) 30 are, in this example, separate connectable parts detachable from one another by separation in a direction parallel to the longitudinal axis, as indicated by the solid arrows in Figure 1. The components 20, 30 are joined together when the device 10 is in use by cooperating engagement elements 21, 31 (for example, a screw or bayonet fitting) which provide mechanical and in some cases electrical connectivity between the power section 20 and the cartridge assembly 30. Electrical connectivity is required if the heater 4 operates by ohmic heating, so that current can be passed through the heater 4 when it is connected to the battery 5. In systems that use inductive heating, electrical connectivity can be omitted if no parts requiring electrical power are located in the cartomiser 30. An inductive work coil can be housed in the power section 20 and supplied with power from the battery 5, and the cartomiser 30 and the power section 20 shaped so that when they are connected, there is an appropriate exposure of the heater 4 to flux generated by the coil for the purpose of generating current flow in the material of the heater. Also, apertures for air flow from the device component 20 to the cartomiser 30 are included at the interfacing parts of the two components 20, 30. The Figure 1 design is merely an example arrangement, and the various parts and features may be differently distributed between the power section 20 and the cartridge assembly section 30, and other components and elements may be included. The two sections may connect together end-to-end in a longitudinal configuration as in Figure 1, or in a different configuration such as a parallel, side-by-side arrangement. The system may or may not be generally cylindrical and / or have a generally longitudinal shape. Either or both sections or components may be intended to be disposed of and replaced when exhausted (the reservoir is empty or the battery is flat, for example), or be intended for multiple uses enabled by actions such as refilling the reservoir and recharging the battery. In other examples, the system 10 may be unitary, in that the parts of the control unit 20 and the cartomiser 30 are comprised in a single housing and cannot be separated. Embodiments and examples of the present disclosure are applicable to any of these configurations and other configurations of which the skilled person will be aware.

[0041] Where an atomiser assembly of a vapour provision system comprises an electrical heater or heating element and a porous member or wick, there is a risk of overheating of the heater if the aerosolisable substrate material or liquid in the wick becomes depleted. This can occur if the flow of liquid from the reservoir to the wick is diminished or interrupted, due to an empty reservoir or a blockage, or if the user is puffing very strongly or rapidly on the vapour provision system so that the rate at which new liquid is drawn into the wick is less than the rate at which liquid is vaporised from the wick. In these situations, the wick become dry, there is a shortage of liquid to be vaporised, and the power supplied to operate the heater is consumed to increase the heater temperature above its normal operating temperature, rather than to vaporise the liquid. The overheated heater can then scorch, char or burn the wick, particularly if the wick comprises a material prone to heat damage of this kind, such as cotton.

[0042] The present disclosure proposes to address this by including a shape memory alloy (SMA) component in the atomiser assembly. The SMA component is formed from a shape memory alloy configured to change its shape from a first shape when the SMA component is a first, lower temperature to a second shape when the SMA component is heated to a second, higher temperature. The SMA component is arranged such that the shape change implemented by an increase to the higher temperature (which can be designated as a threshold temperature) causes a rearrangement of the spatial configuration of the atomiser assembly. At the lower temperature the first shape of the SMA component maintains the heating element and the wick in a first spatial relationship, and the change to the second shape when the SMA component reaches the threshold temperature places the heating element and the wick into a second spatial relationship in which the heating element and the wick have a greater separation from one another than in the first spatial relationship. The first spatial relationship can be an operational spatial relationship in which the heating element, when running at its usual operating temperature (or within an operating temperature range) for vaporising aerosolisable substrate material, is enabled to vaporise aerosolisable substrate material present in the porous member. For example, the heating element is in contact with, or in close proximity to, the porous member. The second spatial relationship includes a spacing or an increased spacing between the heating element and the porous member such that the porous member experiences reduced exposure to heat output by the heating element, and the risk of burning of the porous member by an overheated heating element is reduced or avoided. The threshold temperature is preferably higher than the operating temperature of the heating element, and the SMA component is located such that it is heated by the heat output from the heating element. If the heating element undergoes overheating to a temperature above its operating temperature, such as due to a shortage of aerosolisable substrate material in the porous element, some of the excess heat in the heating element is transferred to the SMA component. The SMA component increases in temperature and when the threshold temperature is reached the SMA component transforms to the second shape. This causes a relative movement between the heating element and the porous member which increases their separation from one another and protects the porous wick from excessive heat exposure from the overheated heater. In addition to overheating caused by liquid depletion, this can also protect the porous wick in the event of electrical malfunction or user error that may increase the power supply to the heating element above the level required for safe operation, causing overheating of the heating element.

[0043] The proposed use of SMA to protect the wick from excess heat exposure uses an effectively automatic process that converts thermal energy, produced directly when overheating of the heating element occurs, into mechanical energy used to separate the wick from the heating element. It does not rely on dedicated power use to operate a sensor or detector or to implement electronic processing, and therefore does not place a drain on the power supply of the vapour provision system.

[0044] An appropriate separation of the heating element and the porous member in the second spatial relationship can be selected according to the design of the atomiser assembly, the form and shape of the heating element and the porous member, the material of the porous member and its vulnerability to excessive heat exposure, and the likely temperature achieved by the heating element when overheated. For many designs of atomiser assembly, a separation up to about 0.5 mm can be adequate. For example a separation in the range of 0.1 - 0.5 mm may be suitable. Larger separations may be implemented if space allows, and for example if suitable existing SMA components that will produce a larger separation are available. A separation of up to 1 mm might be arranged, for example. Smaller or larger separations than these examples are not excluded, however. The numerical value of the separation can be defined as a minimum separation (minimum distance between the heating element and the porous member) in the second spatial relationship, in configurations in which the design of the heating element and / or the wick, and / or their relative positions in the second spatial relationship, gives a non-uniform space between the two parts when they are separated. In other configurations, the distance between the heating element and the porous member when separated in the second spatial relationship may be substantially the same at all points. The SMA component can be shaped, sized, designed, positioned and associated with the heating element and the porous member to produce the required separation or minimum separation when it adopts its second shape.

[0045] Shape memory alloys are metal-containing alloy materials that can exist in two different phases, arising from three different crystal structures: twinned martensite, detwinned martensite, and austenite. For the purposes of the present disclosure, these can be considered as two crystal structures: martensite and austenite. The shape-memory properties arise from thermo-mechanical behaviour governed by a phase transformation between the martensite and austenite crystal structures. The crystals are oriented differently in the two crystal structures, causing different external shapes of the material. A transformation between the crystal structures can be achieved by applied stress (mechanical load) or a change in temperature. Accordingly, a temperature change across a relevant temperature boundary or threshold applied to a shape memory alloy component causes the component to change between a shape adopted with the martensite crystal structure and a shape adopted with the austenite crystal structure. The transformation is not timedependent, so the material is considered to have a “shape memory”, retaining one shape under a constant temperature above or below the temperature boundary, and attaining a different shape when its temperature crosses the boundary.

[0046] For the presently proposed application, a shape memory component is configured to have a first shape, corresponding to the martensite crystal structure, at or below a first, lower temperature (the martensite temperature, Mt), and a second shape, corresponding to the austenite crystal structure, at or above a second, higher temperature (the austenite temperature, At). Since these temperatures vary according to the type of SMA (the metals in the alloy) the component is formed from an SMA for which the boundary between the first temperature and the second temperature corresponds to a temperature above the intended operating temperature of the heating element. For normal operation of the atomiser, the heater and the SMA will be at or below the martensite temperature, and in its first shape. The SMA component is configured, and associated with the heating element and the porous member, such that the first shape maintains the atomiser in the first spatial relationship, for vapour generation. When a situation occurs that causes the heating element to overheat, and produces a temperature rise in the associated SMA component, the SMA component heats above the martensite temperature and begins to adopt its second shape, which is attained with the temperature reaches the austenite temperature, and the SMA component is transformed to the second shape. This changes the spatial configuration of the atomiser to the second spatial relationship, and the separation of the heating element and the porous member is increased compared to the first spatial relationship.

[0047] To achieve this, the SMA component can be configured such that the change from the first shape to the second shape causes an increase in at least one external dimension of the SMA component. This increase is employed such that the SMA component acts on or within one or both of the heating element and the porous member to move one or both of the heating element and the porous member away from the other, by situating the SMA component within the atomiser such that the change of shape produces the required movement.

[0048] Figure 2 shows a schematic representation of a suitable temperature regime for implementing an atomiser assembly according to an example of the disclosure. A temperature scale for the temperature T of the heating element and / or the SMA component is indicated. At the lower end of the scale, there is an operating temperature range ATo within which the heating element heats and vaporises aerosolisable substrate material from the porous element. Purely as an example, a typical range of operating temperatures for a heating element in the atomiser of a vapour provision system may be 260°C - 280°C. The vapour provision system may be configured to allow the user to adjust the operating temperature (via the amount of supplied electrical power) within the operating temperature range, and / or the system may experience normal fluctuations in operating temperature such as caused by slight variability in the rate of liquid supply at the porous element, for example. When the atomiser is working within the operating temperature range, or when the vapour provision system is not operational and the heating element is cool or cooling from the operating temperature, the SMA component will be in its first shape. The martensite temperature Mt is at (in this example) or slightly above (more generally) the highest temperature in the defined operating temperature range ATo, when the SMA component will begin to transform or change shape to the second shape. Hence, the SMA component begins to change shape if the heating element begins to overheat above its maximum intended operating temperature. The shape change of the SMA component continues as the temperature increases until the austenite temperature At is reached, at which the SMA assumes its second shape. The heating element and the porous member are now separated by a distance sufficient to protect the porous member by avoiding at least some heat damage of the porous member caused by exposure to the overheated heating element. This reduced risk of heat damage may be enabled over a protected temperature range ATp which extends upwardly from the austenite temperature. Depending on the size of the protective separating gap between the heating element and the porous member, and the material of porous member, there may be a temperature Tb above the upper limit of ATp at which the separation in no longer large enough to offer useful protection of the porous element. Usefully, therefore, the SMA component is configured to provide a large enough separation such that Tb is a higher temperature than the heating element is able to reach (due to power limitations of the battery, or failure of the heating element at elevated temperatures, for example). Alternatively the vapour provision system may be configured to disable the supply of power to the heating element when it is detected that the heating element has overheated, so that Tb is not reached (by use of a temperature sensor to monitor the heating element, for example).

[0049] The austenite temperature At can be defined as the threshold temperature at which the SMA component assumes its second shape. The alloy used for the SMA component may be selected such that the austenite temperature corresponds to a temperature at which the porous element would begin to experience heat damage if not separated from the heating element. Purely as an example, for a cotton porous element, this temperature might be at or around 300°C. Accordingly, the SMA component will have fully assumed the second shape and placed the porous element in a position of reduced risk of thermal damage as the temperature at which such damage starts to occur is reached. A margin may be introduced by having the austenite temperature below this temperature at which heat damage would otherwise occur. The shape transformation is not an instantaneous effect; rather there is a temperature range between the martensite temperature Mt (below which the SMA component has the first shape) and the austenite temperature At (above which the SMA component has the second shape) during which the shape change occurs. This is indicated by the hashed region in Figure 2. In other examples, the threshold temperature might be defined as lying between the martensite temperature and the austenite temperature, as the SMA approaches its final second shape. Taking the above numerical values, and generalising somewhat to accommodate different designs of vapour provision systems and different types of aerosolisable substrate material having different vaporisation temperatures, the threshold temperature might be chosen to be in the range of 260°C - 300°C, purely as an example. For instance, the threshold temperature might be at least 280°C. The temperature Tb might be around 350°, also as an example. Other values are not excluded however, and will be apparent to the skilled person according to the design of the atomiser. The aim is that the threshold temperature at which the SMA component assumes the second shape is a temperature reached by the heating element when it has overheated above its normal operating temperature and acquired a temperature at or above which the porous member, when drying out or dried out, is liable to damage from heat exposure.

[0050] A large variety of shape memory alloys are known, with a range of properties. In particular, properties that can vary between different SMAs are the value of the martensite temperature and the value of the austenite temperature. An SMA for the shape memory alloy component should therefore be selected with reference to the intended operating temperature of the atomiser. The choice of SMA should be such that the shape change from the first shape to the second shape begins at a temperature above the intended operating temperature or operating temperature range of the heating element, so that the first spatial relationship of the atomiser is maintained during normal operating conditions. However, the temperature of the shape change should be only a relatively small amount above the intended operating temperature or operating temperature range so that the shape change is completed (the second spatial relationship of the atomiser is in place) before the excess heat from the overheated heating element can cause unwanted damage to the porous member. Hence, the martensite temperature is preferably at or only slightly above the maximum intended operating temperature of the heating element, and the austenite temperature is preferably not substantially higher than the martensite temperature. For example, an SMA is which the martensite temperature and the austenite temperature are separated by not more than 10°C, or not more than 15°C, or not more than 20°C, or not more than 25°C could be used.

[0051] A shape memory alloy may be a two-way effect shape memory alloy, or a one-way effect shape memory alloy, and both these types of SMA may be used to implement the currently proposed concept. A two-way effect shape memory alloy is a SMA in which the shape change between the first shape and the second shape occurs in both directions. The shape change is reversible under heating and cooling. When the SMA component is below the martensite temperature, it maintains its first shape. Above the martensite temperature the SMA component begins to change towards the second shape, and the second shape is assumed when the SMA component reaches the austenite temperature. Above the austenite temperature the second shape is maintained. If the SMA component cools below the austenite temperature, it begins to change back to the first shape, and when the martensite temperature is reached, the first shape is assumed. Note that the change of shape during heating from the martensite temperature and the austenite temperature is at a different rate from the change of shape during cooling from the austenite temperature to the martensite temperature. The rates of change effectively follow a hysteresis-like loop. In the context of the present disclosure, a SMA component formed from two-way effect shape memory alloy enables an atomiser to be reused after overheating of the heating element has occurred. The overheating heats the SMA component, which adopts its second shape and places the atomiser into the second spatial relationship to protect the porous element. Later, as the heating element cools (after the power supply to the heating element has been interrupted, or the user’s puffing rate decreases, for example), the SMA component also cools and resumes its first shape, placing the atomiser back in the first spatial relationship. Subsequent vaporisation can then take place. The atomiser can be protected from dry-out damage repeatedly over its lifetime, allowing the reservoir to be refilled multiple times after it has emptied and caused a reduced amount of aerosolisable substrate material in the porous member, for example.

[0052] In contrast, a one-way effect shape memory alloy is a SMA in which the shape change from the first shape to the second shape occurs in one direction only, and is not reversible under subsequent temperature changes. As with a two-way effect SMA, the SMA component maintains its first shape when below the martensite temperature, and begins to change towards the second shape when the martensite temperature is exceeded. The SMA component assumes its second shape when the austenite temperature is reached. The second shape is maintained above the austenite temperature, but is also maintained when the SMA component cools below the austenite temperature. There is no return to the first shape even below the martensite temperature.

[0053] In the context of the present disclosure, a SMA component formed from one-way effect shape memory alloy allows an atomiser to be permanently disabled when overheating of the heating element has occurred. This may be useful in the context of a cartridge or cartomiser component which is intended to be disposable (a consumable component). The cartridge contains an atomiser comprising a one-way effect SMA component, and a reservoir which is intended not be refilled once all the aerosolisable substrate material within it has been consumed. When the reservoir becomes empty, the supply of aerosolisable substrate material to the heating element ceases, the porous element becomes dry, the heating element overheats above its operating temperature, and the SMA component reconfigures the atomiser into the second spatial relationship. In the second spatial relationship, the atomiser is effectively inoperable, since the heating element is separated from the porous element by too great a distance for effective vaporisation of any aerosolisable substrate material in the porous element. Hence, if the user contrives to refill the reservoir so that the supply of aerosol substrate material to the atomiser is restored, the cartridge cannot by used for further aerosol generation. This can be used to prevent the re-use of disposable cartridges, in order to protect the use of unauthorised, and potentially unsuitable aerosolisable substrate material, for example. Examples of suitable shape memory alloys include CuZnAI (two-way effect SMA), NiTi (two-way effect SMA) and NiAl (one-way effect SMA). Other SMAs are not excluded and may be used as preferred. The alloy formula of an SMA can be modified, and a component made from the SMA can be trained in order to achieve shape transformation at the required temperature or in the required temperature range, as will be understood by the skilled person.

[0054] The atomiser may comprise one or more SMA components, as considered most convenient and effective for producing the desired increased separation between the heating element (or heating elements) and the porous member when the second spatial configuration is adopted.

[0055] In some example configurations, the SMA component or components is / are distinct from the heating element and the porous member. In such examples, the SMA component(s) may be arranged between the heating element and the porous member, and configured so that the change to the second shape increases the size of the SMA component along a direction that causes a relative movement of the heating element and the porous member away from one another. In other words, the change to the second shape pushes the heating element and the porous member apart from one another. The SMA component(s) may be mounted directly between the heating element and the porous member. Alternatively, one of the heating element and the porous member may be supported on a substrate which also supports the SMA component(s), and the other of the heating element and the porous member may be mounted on the SMA component. The heating element and the porous member may be arranged substantially parallel to one another when in the first, operational, spatial relationship. The heating element and the porous member may have generally elongate shapes, and be arranged with their longitudinal axes parallel, for example. In other examples, the heating element and the porous member may have substantially planar shapes (or the heating element may be shaped wire or stamped metal heating element with various bends or curves within the same plane to give an overall planar shape), and be arranged in parallel planes.

[0056] Figure 3A shows a simplified schematic representation (side view) of a first example of an atomiser assembly configured with two distinct SMA components. The atomiser assembly comprises a heating element 4 of a generally elongate or planar format, and a porous member 6 also of a generally elongate or planar format. The heating element 4 and the porous member 6 are arranged substantially parallel to one another. Either or both of the heating element 4 and the porous member 6 may be mounted on a supported substrate (not shown). Two SMA components 25, indicated highly schematically in a generalised form, are arranged between the heating element 4 and the porous member 6, one SMA component 25 towards one end or side of the atomiser assembly and the other SMA component towards the opposite end or side of the atomiser assembly. The atomiser assembly is shown with the heating element 4 and the porous member 6 in a first spatial relationship, in which the SMA components are in their first shape, maintaining the heating element 4 and the porous member 6 at a first separation S1, which is small, or may be zero so that the heating element 4 and the porous member 6 are in contact with one another. The close proximity of the heating element 4 and the porous member 6 renders the atomiser assembly operational in that heat energy from the heating element 4 is able to vaporise aerosolisable substrate material absorbed in the porous member 6. Note that electrical contacts or connections required for the provision of electrical power to the heating element in order to operate the atomiser assembly for vapour generation are omitted for clarity here and elsewhere but should be assumed to be provided where not specifically indicated.

[0057] Figure 3B shows the atomiser assembly of Figure 3A in a second spatial relationship. The heating element 4 has increased in temperature above its maximum intended operational temperature. The SMA components 25 are in contact with (or otherwise in a thermal transfer relationship with) the heating element 4 and have also increased in temperature so that a change of shape to their second shape when the temperature of the SMA components 25 reaches their threshold temperature has been produced. When in the second shape, the SMA components have a greater dimension along the direction orthogonal to the planes of the heating element 4 and the porous member 6, so that the heating element 4 and the porous member 6 have been pushed apart and now have a greater separation S2 than when in the first spatial relationship S1 of Figure 3A. The porous member 6 is now further from the heating element 4 and is at a reduced risk of heat damage. In this example, the heating element 4 is held fixed (by the design of the mounting or securing of the atomiser assembly with the cartridge of the vapour provision system) and the porous member 6 is unfixed other than by its association with the SMA components 25. Therefore, the porous member 6 has been moved away from the heating element 4 by the change of shape and corresponding dimensional increase of the SMA components 25. This is indicated by the bold arrow.

[0058] Figure 3C shows a modification of the atomiser assembly of Figure 3A. As in Figure 3B, the atomiser assembly is shown with the heating element 4 and the porous member 6 in the second spatial relationship. In this case, however, the porous member 6 is held fixed, and the heating element 4 is unfixed other than by its association with the SMA components 25. For example, the heating element 4 is mounted on an end of each SMA component 25 via a thermally conductive coupling so that heat transfers from the heating element 6 to the SMA components 25. Therefore, in this case the heating element 4 has been moved away from the porous member 6 by the change in shape and corresponding dimensional increase of the SMA components 25. This is indicated by the bold arrow. Figure 3D shows another modification of the atomiser assembly of Figure 3A. Again, as in 3B, the atomiser assembly is shown with the heating element 4 and the porous member 6 in the second spatial relationship. In this case, however, neither the porous member 6 or the heating element 4 is fixed other than by its association with the SMA components 25. Therefore, in this case both the porous member 6 and the heating element 4 has been moved, each away from the other to increase their separation, by the change in shape and corresponding dimensional increase of the SMA components 25. This is indicated by the bold arrow.

[0059] Figure 4A shows a simplified schematic representation (side view) of another example of an atomiser assembly configured with two distinct SMA components. In this example, the atomiser assembly additionally comprises a substrate 26 on which the heating element 4 is mounted or otherwise supported. The substrate 26 has a substantially flat or planar upper (in the orientation depicted, which may not be the orientation of the atomiser assembly within the cartridge) surface (or other shape appropriate for the shape of the heating element 4) on which heating element 4 is received, placed or formed. The heating element 4 may or may not be in contact with the substrate 26, and may or may not be secured thereto via one or more mounts or electrical contacts. A substrate 26 may be useful is the heating element 4 has a relatively flimsy configuration which is not well self-supported, such being formed from a thin wire, for example. In other examples, the heating element 4 may be printed onto the surface of the substrate 26. The SMA components 25 are arranged on the upper surface of the heating element 4, in thermal contact therewith. In other examples, the SMA components may be mounted onto the upper surface, or the side surfaces, of the substrate 26 externally of the heating element 4. Thermal conduction may be provided between the heating element 4 and the substrate 26 by additional thermal conducting elements (not shown) or by the SMA components being in contact with edges of the heating element 4. The porous member 6 is mounted onto or otherwise coupled to the upper ends or upper portions of the SMA components 26.

[0060] Figure 4B shows a simplified schematic representation (side view) of another example of an atomiser assembly with distinct SMA components and a substrate. In this example, the porous member 6 is mounted or otherwise held or supported on the upper surface of the substrate 26. Two SMA components 25 are provided, one towards each side of the upper surface of the substrate 26, and arranged directly on, or coupled to, the substrate (on its upper or side surfaces) externally of the porous member 6. In other examples, the SMA components might be located on the upper surface of the porous member 6 (similarly to how the SMA components are on the upper surface of the heating element in Figure 4A). The heating element 4 is mounted or otherwise coupled to the upper ends or upper portions of the SMA components 25. In the preceding examples, a pair of SMA components is provided, at substantially opposite sides or ends of the atomiser assembly. If the SMA components are of the same design as one another so that they display the same dimensional increase when changed to their second shape, the separation introduced between the heating element and the porous member in the second spatial relationship will be substantially uniform and of constant depth for the depicted parallel arrangements of the heating element and the porous member. In this way, all parts of the porous member are moved away from the heating element by the same amount and are offered the same protection from heat exposure, assuming the heating element has a uniform configuration and hence a uniform heat output (uniform heating profile). Additional SMA components may be added at other positions in order to assist with placing the atomiser into the second spatial configuration.

[0061] In other designs, for example if the heating element has a non-uniform heating profile and / or the heating element and / or porous member has a more complex shape, it may be appropriate or sufficient to implement a non-constant depth of separation between the heating element and the porous member. This can be achieved by an irregular distribution of SMA components that move part(s) of the porous member or the heating element more than other parts, for example. This could be used to produce a tilted position of one of the heating element or the porous member relative to the other, where the separation is greater near to the SMA component(s).

[0062] Figure 5 shows a simplified schematic representation (side view) of an example of an atomiser assembly configured for a non-uniform separation of the heating element and the porous member. The atomiser assembly is shown in its second spatial relationship, having a single SMA component 25 shown in its second shape. The SMA component 25 is arranged between the heating element 4 and the porous member 6 which substantially parallel to one another in the first spatial relationship, as before, and located at one end or side of the atomiser assembly. Hence, the increase in size of the SMA component 25 when it adopts its second shape lifts one side or edge or corner of the porous member 6 (assuming a fixed heating element 4) only. The separation from the heating element is increased a maximum amount near the SMA component 25, and increased less away from the SMA component; the porous member 6 is thereby titled or angled with respect to the heating element 4.

[0063] In another example (not shown) a single SMA component may be located substantially centrally between the heating element 4 and the porous member 6 so that the movement caused by the shape change is applied at or near the midpoint of one or both parts, and a substantially uniform separation is produced in the second spatial relationship (assuming a parallel heating element 4 and porous member 6 in the first spatial relationship).

[0064] Figure 6 shows a simplified perspective view of an example atomiser assembly having a substrate. The substrate 26 is planar, and the heating element 4 is arranged on the upper surface of the substrate. The heating element 4 is a linear element having a zig-zag or serpentine shape, formed from wire, or from stamped metal, or printed onto the substrate 26. The porous member 6 is planar, and is arranged over the heating element 4, parallel to the plane of the heating element 4 and the upper surface of the substrate 26. Two SMA components 25 are located between the heating element 4 and the porous member, towards opposite ends of the heating element 4, and directly over the heating element 4 so as to be in thermal contact with the heating element 4. The porous member 6 is supported on the upper ends of the SMA components 25. In other examples, more or fewer SMA components 25 might be included. Also, the SMA components 25 might be located away from the heating element 4, but still provided with thermal coupling to the heating element 4, such as by thermally conducting tracks connecting the SMA components 25 to the heating element 4, or by the substrate itself being thermally conductive.

[0065] The heating element may have any shape, and is not limited to the example shown in Figure 6. A linear heating element may have other bent or curved shapes, in two or three dimensions, or may be straight. The heating element may have a planar or block format rather than being linear, or a curved two-dimensional shape. The heating element may be formed from a mesh or grid of conductive fibres or wires, such as metallic fibres or wires. The heating element is provided with suitable electrical contacts or connections for receiving electrical power from the battery of the vapour provision system.

[0066] The SMA component or components, in the examples where the components are distinct from the heating element and the porous member, may be configured with any first shape and second shape that correspond to a suitably sized increase in the dimension of the SMA component along the direction in which the heating element and the porous member are required to be separated. Dimensional increases in other directions may also occur, depending on the configuration chosen for the SMA components. Some examples will now be described. However, these are in no way limiting, and the skilled person will readily appreciate that other first and second shapes can readily be employed which will produce the required movement of the heating element and the porous member to an increased separation.

[0067] Figure 7A shows a schematic side view of a first example of a suitable SMA component. In this example, the SMA component 25 has the form of a coil or helical spring. In the first shape, the coil spring has its turns wound at a first, smaller, pitch, corresponding to a shorter length or height of the spring S1. When the coil spring is heated it transforms to its second shape, indicated by the arrow. Now, the coil spring has its turns wound at a second, larger, pitch, giving a greater length or height S2 to the spring. Coil springs formed from shape memory alloys are readily available so may be convenient choice of shape for the current proposal. In other examples, the SMA component may have a simpler curved or bent format, that increases its dimension in its second shape by decreasing the amount of curvature or bending. The following are some possibilities.

[0068] Figure 7B show a schematic side view of a second example of a suitable SMA component. The SMA component 25 comprises two straight arm portions connected at an angled joint having an angle size 0. In the first shape, the angle 0 is small, so that the arms are close together and the SMA component 25 has a small height S1. When heated, the transformation to the second shape opens up the angled joint to a larger value of 0, so the arms pivot further away from one another, and the SMA component assumes a larger height S2.

[0069] Figure 7C shows a schematic side view of a third example of a suitable SMA component. The SMA component 25 is similar to that of Figure 7B, but in this case the two arm portions are curved or arcuate instead of straight, but are again connected at an angled joint of angle size 0. The SMA component 25 therefore has a form similar to a leaf spring. As in the Figure 7B example, in the first shape, the angle 0 is smaller, the arms are close and the height S1 is small. The transformation to the second shape increases the angle 0 of the joint to give a large height S2 for the SMA component 25.

[0070] Figure 7D shows a schematic side view of a fourth example of a suitable SMA component. In this example, the SMA component 25 has the form of a curved bar or rod in its first shape, with a corresponding height S1 given by the separation of its two ends. The change to the second shape, when heated, decreases the curvature of the bar until the bar is straight, now having a correspondingly greater height S2 because the ends of the bar are now separated by the complete length of the rod. Other second shapes in which the bar straightens only partially are further alternatives.

[0071] In other examples, the SMA component or components are integral with the heating element. Shape memory alloy may form at least part of the heating element, such as one part or several parts, or the whole of the heating element may be formed from shape memory alloy. Hence, all or part of the heating element provides the SMA component(s) in these examples. This is feasible since shape memory alloys are a metallic material and therefore electrically conductive, so can be formed and operated as electrical heating elements in the same manner as electrical heating elements formed from other metals. Shape memory alloy is integrated into one or more parts of heater so that when the SMA component(s) change to their second shape, the heating element as a whole changes its shape into a configuration that places it at a greater distance or separation from the porous member. It will be apparent to the skilled person that the heating element may be configured in various shapes and designs that can operate in this way, and the disclosure is not limited in this regard. Some examples will be described, but other examples may be readily conceived.

[0072] Figure 8A shows a simplified schematic representation of a first example of an atomiser assembly in which SMA components are integrated with the heating element. The atomiser assembly comprises a substrate 26 supporting a porous member 6. A heating element 4 is configured to have the shape of a bridge that spans the porous member 6, passing over the porous member 6 with a small or zero clearance spacing S1 in the depicted first spatial relationship. The heating element 4 comprise a leg part or supporting part at each end, which is mounted on the substrate 26 to hold the heating element 4 in position over the porous member 6. The legs are formed from shape memory alloy, and indeed the whole of the heating element 4 may be formed from shape memory alloy, so that the legs provide the SMA components 25 of the atomiser assembly. The legs are provided with electrical connections or contacts 27 by which electrical current is fed through the heating element 4 in order to operate the atomiser, so that the legs, formed from shape memory alloy, are part of the heating element. The SMA components 25 formed to have a bent or folded configuration in their first shape, which retain the remainder of the heating element 4 in close proximity above the porous member 6.

[0073] Figure 8B shows the atomiser assembly of Figure 8A in its second spatial relationship, in which the SMA components 25 are in their second shape, assumed after overheating of the heating element 4. The second shape is a straight shape, in which the bent configuration of the first shape is straightened. In this way, the height of the legs of the heating element 4 is increased, and the heating element 4 is raised higher above the porous member 6. The separation of the heating element 4 from the porous member 6 is thereby increased to a larger separation S2.

[0074] Figure 9 shows a simplified perspective view of a further example of an atomiser assembly in which SMA components are integrated with the heating element. In this example, the heating element 4 has a generally tubular shape, and surrounds the porous member 6, which has a generally elongate shape arranged along the longitudinal axis of the hollow tubular heating element 4. The heating element 4 is represented schematically only but may take any of several formats, such as a series of loops, turns or coils around the porous member, a tube of conductive (metallic) mesh material, or a tube of sheet metal, the cross section of the heating element 4 may be circular as shown or some other shape. The heating element 4 is configured to comprise one or more portions formed from shape memory to provide one or more SMA components (not indicated here). When the SMA components are in their first shape, the tubular heating element has a first perimeter or circumference which is relatively small so that the tube is narrow and the heating element 4 is closely spaced or in contact with the surface of the porous member 6 for vaporising operation. This is the first spatial relationship of the atomiser assembly. When the SMA components are in their second shape, the perimeter or circumference of the tube is expanded so that the tube is wider and the heating element 4 is spaced further apart from the porous member 6 at some or points around its perimeter. This is the second spatial relationship of the atomiser assembly.

[0075] Figure 10 shows a simplified schematic end view of an atomiser assembly of the type shown in Figure 9. As can be seen, the porous member 6 is disposed centrally at the centre of the hollow tubular heating element 4. The heating element is comprised off two arcuate portions (which may or may not be formed of shape memory alloy) which are joined to each other along adjacent edges by connecting portions of shape memory alloy providing SMA components 25. In the first spatial relationship the SMA components each have a first shape which is folded, the two ends of the folded shape joined to the arcuate portions of the heating element. The fold has a small angle so that the ends of the SMA components 25 are close together. The arcuate portions of the heating element 4 are therefore also close together, and the heating element 4 has a small perimeter that gives it a small separation S1 from the porous member 6 at its centre. Upon heating the SMA components assume their second shape, the transformation indicated by the arrow. In the second shape, the SMA components 25 unfold and become straight (or straighter). The ends therefore move further apart and push the arcuate portions of the heating element away from one another. The perimeter of the heating element 4 is thereby increased, and its separation from the porous member 6 is also increased to S2. This is the second spatial relationship of the atomiser. The SMA components 25 can be thought of as pleats in the heating element 4 which can be folded and unfolded to move the heating element 4 away from or closer to the porous member 6. More pleats may be provided than the two shown in Figure 10..

[0076] Folded, bent or curved portions can be otherwise incorporated into a tubular heating element such that unfolding or unbending or a general increase in bend angles or curvatures causes an expansion or increase in the perimeter of the heating element.

[0077] Figure 11 show a perspective view of an example heating element configured in this way, which can be entirely formed from shape memory alloy. A plurality of curves or bends are formed in a continuous sequence in strips or thin portions of shape memory alloy which are joined to form a complete circle or other tubular shape. Opening of the curves or bends increases the perimeter of the tubular heating element, as before.

[0078] While a variety of shapes and configurations of SMA components have been described herein, alternatives which perform the same function will be readily apparent to the skilled person and not excluded.

[0079] In addition to shape memory alloys, shape memory polymers (SMPs) are also known. Currently known SMPs generally transform at temperatures which are lower than the vaporisation temperatures of currently used aerosol generating substrates, but in the event that higher temperature SMPs and / or lower temperature aerosol generating substrates become readily available, it will be possible to also implement the presently proposed concept with components formed from SMPs rather than SMAs. Accordingly, atomiser assembly designs with SMP components are also included in the scope of the present disclosure, where various features described in the context of SMA components are also applicable to SMP components.

[0080] In conclusion, in order to address various issues and advance the art, this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and / or exclusive. They are presented only to assist in understanding and to teach the claimed invention(s). It is to be understood that advantages, embodiments, examples, functions, features, structures, and / or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claims. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. other than those specifically described herein. The disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

Claims1. An atomiser assembly for a vapour provision system comprising: a heating element for vaporising aerosol-generating substrate; a porous member for delivering aerosol-generating substrate to the heating element; and a shape memory alloy component changeable from a first shape which maintains the heating element and the porous member in a first spatial relationship, to a second shape which places the heating element and the porous member in a second spatial relationship in which the heating element and the porous member have a greater separation than in the first spatial relationship, the second shape being assumed when the shape memory alloy component is heated to a threshold temperature.

2. An atomiser assembly according to claim 1 , wherein the first spatial relationship enables the heating element, when heated to an operating temperature, to vaporise aerosolgenerating substrate in the porous member.

3. An atomiser assembly according to claim 1 or claim 2, wherein the threshold temperature is higher than an operating temperature of the heating element during vaporisation of the aerosol-generating substrate.

4. An atomiser assembly according to any one of claims 1 to 3 wherein the threshold temperature is in the range of 260°C to 300°C.

5. An atomiser assembly according to any one of claims 1 to 3, wherein the threshold temperature is at least 280°C.

6. An atomiser assembly according to any preceding claim, wherein in the second spatial relationship the heating element and the porous member have a separation in the range of 0.1 mm to 0.5 mm.

7. An atomiser assembly according to any preceding claim, wherein the shape memory alloy component is formed from CuZnAI, NiTi or NiAI.

8. An atomiser assembly according to any one of claims 1 to 6, wherein the shape memory alloy component is formed from a two-way effect shape memory alloy configured toresume the first shape from the second shape when the shape memory alloy component cools to a temperature below the threshold temperature.

9. An atomiser assembly according to any one of claims 1 to 6, wherein the shape memory alloy component is formed from a one-way effect shape memory alloy configured to maintain the second shape when the shape memory alloy component cools below the threshold temperature.

10. An atomiser assembly according to any one of claims 1 to 9, wherein the shape memory alloy component is distinct from the heating element and the porous member.

11. An atomiser assembly according to claim 10, wherein the shape memory alloy component is arranged between the heating element and the porous member, or between the heating element or porous member and a substrate supporting the other of the heating element or porous member.

12. An atomiser assembly according to claim 10 or claim 11 , wherein the porous member is fixed, and the change of the shape memory alloy component to the second shape moves the heating element away from the porous member.

13. An atomiser assembly according to claim 10 or claim 11, wherein the heating element is fixed, and the change of the shape memory alloy component to the second shape moves the porous member away from the heating element.

14. An atomiser assembly according to claim 10 or claim 11, wherein the change of the shape memory alloy component to the second shape moves both the porous member and the heating element to increase their separation.

15. An atomiser assembly according to any one of claims 10 to 14, wherein the shape memory alloy component is formed as a spring.

16. An atomiser assembly according to any preceding claim, wherein the heating element and / or the porous member has a planar shape.

17. An atomiser assembly according to any one of claims 1 to 9, wherein shape memory alloy component forms at least part of the heating element.

18. An atomiser assembly according to claim 17, wherein the heating element has a generally tubular shape and is disposed around the porous member.

19. An atomiser assembly according to claim 18, wherein the change of the shape memory alloy component to the second shape causes an increase in the perimeter of the heating element to move the heating element outwardly from the porous member.

20. An atomiser assembly according to any preceding claim, further comprising one or more additional shape memory components.

21. An atomiser assembly according to any preceding claim, wherein the heating element has a mesh structure.

22. An atomiser assembly according to any preceding claim, wherein the porous element comprises cotton.

23. A component for a vapour provision system, the component comprising an atomiser assembly according to any one of claims 1 to 22.

24. A vapour provision system comprising an atomiser assembly according to any one of claims 1 to 21 or a component according to claim 23.

25. An atomiser assembly for a vapour provision system comprising: a heating element for vaporising aerosol-generating substrate; a porous member for delivering aerosol-generating substrate to the heating element; and a shape memory polymer component changeable from a first shape which maintains the heating element and the porous member in a first spatial relationship, to a second shape which places the heating element and the porous member in a second spatial relationship in which the heating element and the porous member have a greater separation than in the first spatial relationship, the second shape being assumed when the shape memory polymer component is heated to a threshold temperature.

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