Field

The present disclosure relates to vapour provision systems such as nicotine delivery systems (e.g. electronic cigarettes and the like).

Background

Electronic vapour provision systems such as electronic cigarettes (e-cigarettes) generally contain a vapour precursor material, such as a reservoir of a source liquid containing a formulation, typically including nicotine, from which a vapour is generated for inhalation by a user, for example through heat vaporisation. Thus, a vapour provision system will typically comprise a vapour generation chamber containing a vaporiser, e.g. a heating element, arranged to vaporise a portion of precursor material to generate a vapour in the vapour generation chamber. As a user inhales on the device and electrical power is supplied to the vaporiser, air is drawn into the device through an inlet hole and along an inlet air channel connecting to the vapour generation chamber where the air mixes with vaporised precursor material to form a condensation aerosol. There is an outlet air channel connecting from the vapour generation chamber to an outlet in the mouthpiece and the air drawn into the vapour generation chamber as a user inhales on the mouthpiece continues along the outlet flow path to the mouthpiece outlet, carrying the vapour with it, for inhalation by the user. Some electronic cigarettes may also include a flavour element in the air flow path through the device to impart additional flavours. Such devices may sometimes be referred to as hybrid devices, and the flavour element may, for example, include a portion of tobacco arranged in the air flow path between the vapour generation chamber and the mouthpiece such that vapour / condensation aerosol drawn through the device passes through the portion of tobacco before exiting the mouthpiece for user inhalation.

For electronic cigarettes using a liquid vapour precursor (e-liquid) there is a risk of the liquid leaking. This is the case for non-hybrid electronic cigarettes and for hybrid devices. Liquid- based e-cigarettes will typically have a capillary wick for transporting liquid from within a liquid reservoir to a vaporiser located in the air channel connecting from the air inlet to the vapour outlet for the e-cigarette. Thus the wick typically passes through an opening in a wall that separates the liquid reservoir from the air channel in the vicinity of the vaporiser.

Figure 1 schematically shows a cross-section of a portion of an electronic cigarette in the vicinity of its vapour generation chamber 2, i.e. the region where vapour is generated during use. The electronic cigarette comprises a central air channel 4 through a surrounding annular liquid reservoir 6. The annular liquid reservoir 6 is defined by an inner wall 8 and an outer wall 10, which may both be cylindrical (the inner wall 8 separates the liquid reservoir 6 from the air channel, and so in that sense the inner wall 8 also defines the air channel). The electronic cigarette comprises a vaporiser 12 in the form of a resistive heating coil. The coil 12 is wrapped around a capillary wick 14. Each end of the capillary wick 14 extends into the liquid reservoir 6 through an opening 16 in the inner wall 8. The wick 14 is thus arranged to convey liquid from within the liquid reservoir 6 to the vicinity of the coil 12 by capillary action. During use an electric current is passed through the coil 12 so that it is heated and vaporises a portion of liquid from the capillary wick 14 adjacent the coil 12 to generate vapour in the vapour generation chamber 2 for user inhalation. The vaporised liquid is then replaced by more liquid being drawn along the wick 14 from the liquid reservoir 6 by capillary action.

Because the reservoir inner wall 8 has openings 16 to allow liquid to be drawn out of the reservoir 6 to the vaporiser 12, there is a corresponding risk of leakage from this part of the electronic cigarette. Leakage is undesirable both from the perspective of the end user naturally not wanting to get the e-liquid on their hands or other items, and also from a reliability perspective, since leakage has the potential to damage the electronic cigarette itself, for example due to corrosion of components which are not intended to come into contact with the liquid.

Various approaches are described herein which seek to help address or mitigate at least some of the issues discussed above.

Summary

According to a first aspect of certain embodiments there is provided a vapour provision system comprising: a housing containing a reservoir of liquid; a vaporiser; and a liquid transport element arranged to transport liquid from the reservoir to the vaporiser for vaporisation, wherein the liquid transport element comprises a first portion extending into the reservoir, a second portion arranged to deliver liquid to the vaporiser, and a third portion connecting between the first portion and the second portion, wherein the third portion is arranged to pass through a channel in the housing, wherein the channel has a cross-section that matches the cross-section of the liquid transport element in the channel and a length which is at least three times the width of the liquid transport element in the channel.

According to another aspect of certain embodiments there is provided vapour provision means comprising: housing means comprising reservoir means for liquid; vaporiser means; and liquid transport element means arranged to transport liquid from the reservoir means to the vaporiser means for vaporisation, wherein the liquid transport element means comprises a first portion extending into the reservoir means, a second portion arranged to deliver liquid to the vaporiser means, and a third portion connecting between the first portion and the second portion, wherein the third portion is arranged to pass through channel means in the housing means, wherein the channel means has a cross-section that matches the cross- section of the liquid transport element means in the channel and a length which is at least three times the width of the liquid transport element means in the channel means.

It will be appreciated that features and aspects of the disclosure described herein in relation to the first and other aspects of the disclosure are equally applicable to, and may be combined with, embodiments of the disclosure according to other aspects of the disclosure as appropriate, and not just in the specific combinations described above.

Brief Description of the Drawings

Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 represents a schematic cross-sectional cut-away view of a vapour generation region of a previously proposed vapour provision system;

Figure 2 represents a schematic cross-sectional cut-away view of a vapour provision system according to certain embodiments of the disclosure;

Figure 3A represents a schematic cross-sectional cut-away view of a portion of the vapour provision system of Figure 2;

Figure 3B represents a schematic cross-sectional cut-away view of the portion of the vapour provision system shown in Figure 3A with fewer elements shown;

Figure 4 represents a schematic cross-sectional cut-away view of the vapour provision system of Figures 2 in a plane perpendicular to its longitudinal axis at the location identified by X in Figure 3A;

Figure 5A represents a schematic cross-sectional cut-away view of a portion of a vapour provision system according to certain other embodiments of the disclosure;

Figure 5B represents a schematic cross-sectional cut-away view of the portion of the vapour provision system shown in Figure 5A with fewer elements shown; and

Figures 6 represents a schematic cross-sectional cut-away view of a portion of a vapour provision system according to certain other embodiments of the disclosure.

Detailed Description

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

The present disclosure relates to vapour provision systems, which may also be referred to as aerosol provision systems, such as e-cigarettes, and including hybrid systems (electronic cigarettes including tobacco or another flavour element separate from the vapour generation region). Throughout the following description the term“e-cigarette” or“electronic cigarette” may sometimes be used, but it will be appreciated this term may be used interchangeably with vapour provision system / device and electronic vapour provision system / device. Furthermore, and as is common in the technical field, the terms "vapour" and "aerosol", and related terms such as "vaporise", "volatilise" and "aerosolise", may generally be used interchangeably.

Vapour provision systems (e-cigarettes) often, though not always, comprise a modular assembly including both a reusable part (control unit part) and a replaceable (disposable) cartridge part. Often the replaceable cartridge part will comprise the vapour precursor material and the vaporiser and the reusable part will comprise the power supply (e.g.

rechargeable battery) and control circuitry. It will be appreciated these different parts may comprise further elements depending on functionality. For example, the reusable device part may comprise a user interface for receiving user input and displaying operating status characteristics, and the replaceable cartridge part may comprise a temperature sensor for helping to control temperature. Cartridges are electrically and mechanically coupled to a control unit for use, for example using a screw thread, latching or bayonet fixing with appropriately engaging electrical contacts. When the vapour precursor material in a cartridge is exhausted, or the user wishes to switch to a different cartridge having a different vapour precursor material, a cartridge may be removed from the control unit and a replacement cartridge attached in its place. Devices conforming to this type of two-part modular configuration may generally be referred to as two-part devices. It is also common for electronic cigarettes to have a generally elongate shape. For the sake of providing a concrete example, certain embodiments of the disclosure described herein will be taken to comprise this kind of generally elongate two-part device employing disposable cartridges. Flowever, it will be appreciated the underlying principles described herein may equally be adopted for different electronic cigarette configurations, for example single-part devices or modular devices comprising more than two parts, refillable devices and single-use disposable devices, as well as devices conforming to other overall shapes, for example based on so-called box-mod high performance devices that typically have a more box-like shape. More generally, it will be appreciated certain embodiments of the disclosure are based on approaches for seeking to help reduce the likelihood of leakage in accordance with the principles described herein, and other constructional and functional aspects of electronic cigarettes implementing approaches in accordance with certain embodiments of the disclosure are not of primary significance and may, for example, be implemented in accordance with any established approaches.

Figures 2 to 4 schematically represent different views of an example e-cigarette 20 in accordance with certain embodiments of the disclosure. In particular, Figure 2 schematically represents a cut-away cross-sectional view of the e-cigarette 20 and Figure 3A

schematically represents a magnified view around a vapour generation region 73 of the e- cigarette 20 (the region indicated by the dashed box labelled A in Figure 2). As described further below, the e-cigarette 20 includes a wick 66 and a wire heater coil 68 and the cross- sectional views of Figures 2 and 3A are in a plane containing the wick and the longitudinal axis of the e-cigarette. Figure 3B is similar to Figure 3A but without the wick 66 and heater 68 being shown. Figure 4 schematically represents a cut-away cross-sectional view of the e- cigarette in a plane perpendicular to the longitudinal axis of the e-cigarette at the positon marked as X in Figure 3A. The view direction for Figure 4 is from top-to-bottom for the orientation represented in Figure 3A.

The e-cigarette 20 comprises two main components, namely a reusable part 22 and a replaceable / disposable cartridge part 24. In normal use the reusable part 22 and the cartridge part 24 are releasably coupled together at an interface 26. When the cartridge part is exhausted or the user simply wishes to switch to a different cartridge part, the cartridge part may be removed from the reusable part and a replacement cartridge part attached to the reusable part in its place. The interface 26 provides a structural, electrical and air path connection between the two parts and may be established in accordance with conventional techniques, for example based around a screw thread, latch mechanism, or bayonet fixing with appropriately arranged electrical contacts and openings for establishing the electrical connection and air path between the two parts as appropriate. The specific manner in which the cartridge part 24 mechanically couples to the reusable part 22 is not significant to the principles described herein, but for the sake of a concrete example is assumed here to comprise a latching mechanism, for example with a portion of the cartridge being received in a corresponding receptacle in the reusable part with cooperating latch engaging elements (not represented in Figures 2 to 4). It will also be appreciated the interface 26 in some implementations may not support an electrical and / or air path connection between the respective parts. For example, in some implementations a vaporiser may be provided in the reusable part rather than in the cartridge part, or the transfer of electrical power from the reusable part to the cartridge part may be wireless (e.g. based on electromagnetic induction), so that an electrical connection between the reusable part and the cartridge part is not needed. Furthermore, in some implementations the airflow through the electronic cigarette might not go through the reusable part so that an air path connection between the reusable part and the cartridge part is not needed.

The cartridge part 24 may in accordance with certain embodiments of the disclosure be broadly conventional apart from where modified in accordance with the approaches described herein. The cartridge part 24 comprises a cartridge housing 62 formed of a plastics material. The cartridge housing 62 supports other components of the cartridge part and provides the mechanical interface 26 with the reusable part 22. In this example the cartridge housing is generally circularly symmetric and connects to the reusable part 22 along the direction of its longitudinal axis (i.e. its axis of longest extent / main direction along which air flows in the cartridge during use). In this example the cartridge part has a length of around 4 cm and a diameter of around 1 .8 cm. However, it will be appreciated the specific geometry, and more generally the overall shape and materials used, may be different in different implementations.

Within the cartridge housing 62 is a reservoir 64 that contains liquid vapour precursor material. The liquid vapour precursor material may be conventional, and may be referred to as e-liquid. The liquid reservoir 64 in this example has an annular shape which is generally circularly symmetric and the cartridge housing 62 includes an outer wall 65 and an inner wall 63 that defines an air path 72 through the cartridge part 24. The reservoir 64 is closed at each end by end walls to contain the e-liquid with the end wall nearest the reusable part including openings for a wick to enter the reservoir as discussed further below. The end wall of the reservoir nearest the interface end of the cartridge is provided by a base portion 69 of the cartridge. The cartridge housing 62 may be formed in accordance with conventional manufacturing techniques, for example using single- or multi-part plastics moulding techniques.

The cartridge part 22 further comprises a wick (liquid transport element) 66 and a heater (vaporiser) 68. The central portion of the wick 66 extends transversely across the cartridge air path 72 and the respective ends of the wick extend into the reservoir 64 of e-liquid through extended channels 67 which, in this example, pass through the base portion 69 of the cartridge part 24 (the channels 67 can be most clearly seen in Figure 3B). As discussed further herein, in accordance with certain embodiments of the disclosure the channels 67 have a length of at least three times the diameter of the wick and a cross-section that is matched (in size and shape) to the wick such that the wick 66 fills the channels 67, for example with the wick being slightly compressed by the walls of the channels 67. In this example each channel 67 has a generally circular cross-section and comprises a first section 67A that extends through the base part 69 in a direction that is perpendicular to the longitudinal axis of the e-cigarette (i.e. extending away from the air flow path 72 in a sideways direction for the orientation shown in Figure 3B) and a second section 67B that extends through the base part 69 in a direction that is parallel to the longitudinal axis of the e-cigarette (i.e. connecting into the bottom end wall of the reservoir 64 in a vertical direction for the orientation shown in Figure 3B). That is to say, in this example, the respective channels each include a change in direction in the base part 69. In the example represented in Figures 2 to 4 the change in direction of the channels is shown as a relatively sharp turn, but in practice a more rounded turn might be used.

During assembly the respective ends of the wick 66 may be threaded through the respective channels 67. In some cases the base part 69 may comprise two components joined at an interface, for example at the interface 77 indicated by a dotted line in Figure 3A. In this case the channels 67 may be defined by cooperating grooves in the upper and lower parts of the base portion 69 at the interface 77. Thus, during assembly, each end of the wick may be fed into the reservoir through the portions of the channel formed in the upper part of the base portion 69 (i.e. the part above the interface for the orientation in Figure 3A) and the middle part of the wick may be aligned with the groove in the upper part of the base portion 69. The lower part of the base portion 69 (i.e. the part below the interface 77) may then be attached so the grooves in the two parts cooperate to form the channels 67 around the wick. This approach of in effect clamping the wick between two components during manufacture may in some cases be considered to simplify assembly. Flowever, it will be appreciated the specific manner in which the channels 67 are formed in the base portion 69 and the manner in which the wick is assembled into the channels 67 is not of primary significance to the principles described herein.

The central portion of the wick 66 and the heater 68 are arranged in the cartridge air path 72 such that a region of the cartridge air path 72 around the wick 66 and heater 68 in effect defines a vaporisation region 73 for the cartridge part. E-liquid in the reservoir 64 infiltrates the wick 66 through the ends of the wick extending into the reservoir 64 and is drawn along the wick (i.e. through the channels 67) by surface tension / capillary action (i.e. wicking). The heater 68 in this example comprises an electrically resistive wire coiled around the wick 66.

In this example the heater 68 comprises a nickel chrome alloy (Cr20Ni80) wire and the wick 66 comprises a glass fibre bundle, but it will be appreciated the specific heater configuration and wick material is not of primary significance to the principles described herein. For example, in some implementations the wick may comprise a plurality of fibres of a different material, for example cotton, or may comprise a non-fibrous material, for example the wick formed of a porous ceramic. In use electrical power may be supplied to the heater 68 to vaporise an amount of e-liquid (vapour precursor material) delivered to the heater 68 by the portion of the wick 66 adjacent the heater 68. Vaporised e-liquid may then become entrained in air drawn along the cartridge air path 72 from the vaporisation region 73 towards the mouthpiece outlet 70 for user inhalation.

The rate at which e-liquid is vaporised by the vaporiser (heater) 68 will generally depend on the amount (level) of power supplied to the heater 68. Thus electrical power can be applied to the heater 66 to selectively generate vapour from the e-liquid in the cartridge part 24, and furthermore, the rate of vapour generation can be changed by changing the amount of power supplied to the heater 68, for example through pulse width and/or frequency modulation techniques.

The reusable part 22 may be conventional and comprises an outer housing 32 with an opening that defines an air inlet 48 for the e-cigarette, a battery 46 for providing operating power for the electronic cigarette, control circuitry 38 for controlling and monitoring the operation of the electronic cigarette, a user input button 34 and a visual display 44.

The outer housing 32 may be formed, for example, from a plastics or metallic material and in this example has a circular cross-section generally conforming to the shape and size of the cartridge part 24 so as to provide a smooth transition between the two parts at the interface 26. In this example, the reusable part has a length of around 8 cm so the overall length of the e-cigarette when the cartridge part and reusable part are coupled together is around 12 cm. However, and as already noted, it will be appreciated that the overall shape and scale of an electronic cigarette implementing an embodiment of the disclosure is not significant to the principles described herein.

The air inlet 48 connects to an air path 50 through the reusable part 22. The reusable part air path 50 in turn connects to the cartridge air path 72 across the interface 26 when the reusable part 22 and cartridge part 24 are connected together. Thus, when a user inhales on the mouthpiece opening 70, air is drawn in through the air inlet 48, along the reusable part air path 50, across the interface 26, through the vapour generation region in the vapour generation region 73 in the vicinity of the atomiser 68 (where vaporised e-liquid becomes entrained in the air flow), along the cartridge air path 72, and out through the mouthpiece opening 70 for user inhalation.

The battery 46 in this example is rechargeable and may be of a conventional type, for example of the kind normally used in electronic cigarettes and other applications requiring provision of relatively high currents over relatively short periods. The battery 46 may be recharged through a charging connector in the reusable part housing 32, for example a USB connector (not shown). The user input button 34 in this example is a conventional mechanical button, for example comprising a spring mounted component which may be pressed by a user to establish an electrical contact. In this regard, the input button may be considered an input device for detecting user input and the specific manner in which the button is implemented is not significant. For example, other forms of mechanical button(s) or touch-sensitive button(s) (e.g. based on capacitive or optical sensing techniques) may be used in other

implementations.

The display 44 is provided to provide a user with a visual indication of various characteristics associated with the electronic cigarette, for example current power setting information, remaining battery power, and so forth. The display may be implemented in various ways. In this example the display 44 comprises a conventional pixilated LCD screen that may be driven to display the desired information in accordance with conventional techniques. In other implementations the display may comprise one or more discrete indicators, for example LEDs, that are arranged to display the desired information, for example through particular colours and / or flash sequences. More generally, the manner in which the display is provided and information is displayed to a user using the display is not significant to the principles described herein. For example, some embodiments may not include a visual display and may include other means for providing a user with information relating to operating characteristics of the electronic cigarette, for example using audio signalling or haptic feedback, or may not include any means for providing a user with information relating to operating characteristics of the electronic cigarette.

The control circuitry 38 is suitably configured / programmed to control the operation of the electronic cigarette to provide functionality in accordance with the established techniques for operating electronic cigarettes. For example, the control circuitry 38 may be configured to control a supply of power from the battery 46 to the heater / vaporiser 68 to generate vapour from a portion of the e-liquid in the cartridge part 24 for user inhalation via the mouthpiece outlet 70 in response to user activation of the input button 34, or in other implementations in response to other triggers, for example in response to detecting user inhalation. As is conventional, the control circuitry (processor circuitry) 38 may be considered to logically comprise various sub-units / circuitry elements associated with different aspects of the electronic cigarette's operation, for example user input detection, power supply control, display driving, and so on. It will be appreciated the functionality of the control circuitry 38 can be provided in various different ways, for example using one or more suitably programmed programmable computer(s) and / or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s) configured to provide the desired functionality. As will be understood from the above discussion, a difference between the vapour provision system / electronic cigarette represented in Figures 2 to 4 and previously proposed electronic cigarettes is the manner in which the liquid transport element / wick 66 couples with the reservoir 64 containing liquid for vaporisation. In particular, in accordance with certain embodiments of the disclosure, respective portions of the liquid transport element 66 pass along respective channels 67 running between the vapour generation region and the reservoir 64. The inventors have recognised that arranging the wick so that it passes through such an extended channel can help reduce the risk of liquid escaping from the reservoir (leakage).

As schematically represented in Figures 2 to 4, in accordance with certain embodiments of the disclosure the cross-sectional area of the channels 67 is matched to the cross-sectional area of the wick within the channels. By this it is meant the wick substantially fills the volume of the channel, for example so a major part of the outer surface of the wick within the channel is in contact with / adjacent to the walls defining the channel. In this regard the wick may be considered to be in contact with / adjacent to the walls defining the channel if a gap between the wick and the channel walls is too small to allow bulk liquid flow (i.e. non capillary flow) because of surface tension effects in this region. In some examples the cross- sectional area of each channel may be broadly consistent along its length, and may be slightly less than the uncompressed cross-sectional area of the portions of the wick passing through the channels so that the wick is compressed by the channel walls. For example, in accordance with certain embodiments of the disclosure the wick may be compressed in the channels by such an amount that its cross-sectional area is reduced compared to its uncompressed cross-sectional area outside the channels by an amount of at least around 5%, for example at least around 10%, for example at least around 15%, for example at least around 20%, for example at least around 25%, for example at least around 30%. More generally, the amount of compression may be different in different implementations. For example, in some cases there may be no compression such that the cross-section of the channels 67 is the same size and shape as the nominal cross-section for the wick, whereas in other cases there may be more than 30% areal compression. The amount of compression may be selected to establish an appropriate compromise between helping to ensure there is a desired degree of sealing between the outer surface of the wick and the inner wall of the channels without unduly restricting fluid flow along the length of the wick. An appropriate degree of compression may, for example, be determined through empirical testing.

The inventors have found the likelihood of leakage can be reduced if the channels have a length is which relatively long compared with a characteristic diameter (width) of the liquid transport element. For example, in accordance with certain embodiments the channels 67 may have a length which is greater than a characteristic diameter (width) of the liquid transport element by a factor of at least around 3, for example at least around 3.5, for example at least around 4, for example at least around 4.5, for example at least around 5.

It will be appreciated the wick will in general not have a strictly circular cross-section, and in that regard, references herein to the diameter / width of the wick may be taken to correspond to the diameter of a circle having the same cross-sectional area as the wick in a plane perpendicular to its axis of extent (i.e. characteristic diameter / width = 2 ^* sqrt(cross- sectional area / pi)). It will also be appreciated the characteristic diameter of the wick material will most likely vary to some extent along the length of the wick material, and in that sense the characteristic diameter / width may be considered to be a length-averaged characteristic diameter (e.g. averaged over a length is greater than the expected scale of typical variations in diameter, for example over two or three centimetres). Thus, while the terms diameter and width may be used herein for simplicity, it will be appreciated this should be interpreted as a reference to a length-averaged characteristic diameter. For example, a diameter corresponding to that of a circle having the same length-average cross-sectional area of the wick material, e.g. averaged over the typical length of a wick in a vaporiser assembly comprising the wick material, for example, averaged over around 1 cm, 2 cm, 3 cm, or more. In that sense the diameter of a section of uncompressed wick material may in some respects be characterised as the diameter of a cylinder having the same length and volume as the uncompressed wick material, and likewise for a section of compressed wick material. Similarly, it will be appreciated the channels may in some cases not have a truly circular cross-section, and in that regard, references herein to the diameter / width of a channel may be taken to correspond to the diameter of a circle having the same cross- sectional area as the channel in a plane perpendicular to its axis of extent (noting the axis of extent may change direction along the channel).

In terms of absolute length, in accordance with certain embodiments of the disclosure the respective channels may each have a length of at least around 5 mm, for example at least around 6 mm, for example at least around 7 mm, for example at least around 8 mm, for example at least around 9 mm, for example at least around 10 mm.

These channel lengths may, for example, be appropriate for use with a wick having a diameter within the channel of between around 1 mm and around 3 mm, for example between around 1.2 mm and around 2.8 mm, for example between around 1 .4 mm and around 2.6 mm, for example between around 1 .5 mm and around 2.5 mm, for example between around 1.7 mm and around 2.3 mm. For the sake of providing a concrete example, it is assumed for the implementation represented in Figures 2 to 4 that the wick has a nominal uncompressed diameter of 2 mm and each channel has a length of around 6 mm and an inner diameter of around 1.8 mm (i.e. so the cross section of the wick is compressed in the channel by around 20%). In examples in which a channel is not straight, for example as in Figures 2 to 4, the channel length may be measured along its centreline. The width of the air channel 72 traversed by the wick in this example is around 5 mm and the respective ends of the wick extend into the reservoir by around 5 mm. Thus, the overall length of the wick in this example is around 27 mm. One characteristic of arrangements in accordance with certain embodiments of the disclosure is that the length of the portions of the wick extending into the reservoir is smaller than the length of the channels through which the wick passes into the reservoir.

Flowever, it will be appreciated the specific geometry for the wick may vary for different implementations. For example, in a relatively high power electronic cigarette that is able to generate a relatively large amount of vapour, a larger wick, and correspondingly larger channels, may be used to help maintain a sufficient supply of liquid to the vaporiser.

Conversely, in a relatively low power electronic cigarette that generates a relatively small amount of vapour, a smaller wick, and correspondingly smaller channels, may be considered more appropriate.

Figures 5A and 5B schematically show a cross-section of a portion of the electronic cigarette / vapour provision system 20 in the vicinity of its vapour generation chamber 73 in accordance with another example embodiment. Various aspects of Figures 5A and 5B are similar to, and will be understood from, corresponding aspects of Figures 3A and 3B and are not described in detail again in the interest of brevity. Flowever, the example of Figures 5A and 5B differs from the example of Figures 3A and 3B in that at least part of the wall of each channel 67 is defined by an insert 82 which is formed separately from the housing. The insert may, for example, comprise a non-wicking resilient material, for example an elastomeric material, which can help with applying a uniform compressive force to the wick 66 within the channel 67. The insert may comprise adhesive to facilitate sealing to the cartridge housing and / or the wick.

Thus in the examples of Figures 2 to 5 the cartridge housing 62 comprises a base part 69 that defines an end (bottom) wall of the reservoir 64 and a side wall of the vapour generation region 73 around the vaporiser 38, and the respective channels extend from an opening in the side wall of the vapour generation region to an opening in the end wall of the reservoir. Flowever, other approaches may be used for providing an extended channel through which the wick passes between the air channel and the reservoir. For example, in some cases, rather than have the channels formed in a base part of the cartridge housing, a channel may instead be formed by a tube connected to / through an opening in a side wall of the reservoir, for example as schematically shown in Figure 6.

Figure 6 schematically shows a cross-section of a portion of an electronic cigarette / vapour provision system in the vicinity of its vapour generation chamber 173 in accordance with another example embodiment. Various aspects of the electronic cigarette / vapour provision system represented in Figure 6 (including aspects which are not themselves shown in Figure 6) are similar to, and will be understood from corresponding aspects of the electronic cigarette / vapour provision system represented in Figure 2 to 4 and are not described in detail again in the interest of brevity. Thus aspects of the electronic cigarette / vapour represented in Figure 6 which are not specifically discussed herein may be implemented in accordance with conventional approaches and / or the approaches discussed elsewhere herein.

Thus Figure 6 represents a portion of a cartridge part of an electronic cigarette according to certain embodiments of the disclosure. The cartridge part may be broadly conventional apart from where modified in accordance with the approaches described herein. The cartridge part comprises a cartridge housing 162 formed of a plastics material. The cartridge housing 162 supports other components of the cartridge part and provides a mechanical interface to a reusable part (e.g. in a similar manner to that described above with reference to Figure 2). In this example the cartridge housing 162 is again generally circularly symmetric and connects to the reusable part along the direction of its longitudinal axis (i.e. its axis of longest extent / main direction along which air flows in the cartridge during use).

Within the cartridge housing 162 is a reservoir 164 that contains liquid vapour precursor material. The liquid vapour precursor material may be conventional, and may be referred to as e-liquid. The liquid reservoir 164 in this example has an annular shape which is generally circularly symmetric and the cartridge housing 162 includes an outer wall 165 and an inner wall 163 that defines an air path 172 through the cartridge part. The reservoir 164 is closed at each end by end walls to contain the e-liquid. The cartridge housing 62 may be formed in accordance with conventional manufacturing techniques, for example using single- or multi part plastics moulding techniques.

The cartridge part further comprises a wick (liquid transport element) 166 and a heater (vaporiser) 168. The central portion of the wick 166 extends transversely across the cartridge air path 172 and the respective ends of the wick extend into the reservoir 164 of e- liquid through extended channels 167 which, in this example, are formed by tubes which extend into the liquid reservoir from an opening in the side wall of the housing 162 separating the reservoir 164 from the air path 172 as shown in Figure 6. As discussed elsewhere herein, in accordance with certain embodiments of the disclosure the channels 167 have a length of at least three times the diameter of the wick and a cross-section that is matched (in size and shape) to the wick such that the wick 166 broadly fills the channels 167, for example with the wick being slightly compressed by the walls of the channels 167 in the same manner as discussed above. In this example each channel 167 again has a generally circular cross-section. During assembly the respective ends of the wick 166 may be threaded from the air channel 172 into the reservoir 164 through the respective channels 167.

The central portion of the wick 166 and heater 168 are arranged in the cartridge air path 172 in the same manner as for the corresponding elements of the examples discussed above with reference to Figures 2 to 5.

Despite the channels being provided in a different manner in Figure 6 as compared with the examples of Figures 2 to 5 (i.e. as tubes extending into the liquid reservoir, as opposed to passageways through a base portion of the housing), it will be appreciated the underlying principles of operation, for example in terms of helping to reduce leakage, are the same for the different examples. It will also be appreciated there are other ways in which an extended channel may be provided in accordance with other examples. For example, whereas in the example of Figure 6 the channels 167 are straight, in other examples they may be bent, for example to allow for a longer length within a given width of reservoir. Furthermore, in other examples a tube forming a channel need not terminate at the side wall, but may extend into the air channel. More generally, it will be appreciated that the specific manner in which the channel is formed is not significant to the principle of passing a wick through a channel with a length of at least three times the diameter of the wick between a liquid reservoir and a vaporiser to seek to help reduce leakage.

While the above-described embodiments have in some respects focussed on some specific example vapour provision systems, it will be appreciated the same principles can be applied for vapour provision systems using other technologies. That is to say, the specific manner in which various aspects of the vapour provision system function are not directly relevant to the principles underlying the examples described herein.

For example, while various example configurations have been discussed above, it will be appreciated the specific manner in which the channels are formed is not of primary significance to the principles described herein, and channels through which the wick extends from the vapour generation region to the reservoir may be provided differently in different implementations. Furthermore, it will be appreciated that whereas in the examples described herein the wick is assumed to have both ends extending into the liquid reservoir, it will be appreciated the same principles may be applied in respect of a wick having only one end extending into a liquid reservoir, or indeed a wick having multiple arms (e.g. a cross-like form) with more than two ends extending into a liquid reservoir.

Furthermore, whereas the above-described embodiments have primarily focused on aerosol provision systems comprising a vaporiser comprising a resistance heater coil, in other examples the vaporiser may comprise other forms of heater, for example a planar heater, in contact with a liquid transport element. Furthermore, in other implementations a heater- based vaporised might be inductively heated. In yet other examples, the principles described above may be adopted in devices which do not use heating to generate vapour, but use other vaporisation technologies, for example piezoelectric excitement.

Furthermore still, and as already noted, whereas the above-described embodiments have focused on approaches in which the aerosol provision system comprises a two-part device, the same principles may be applied in respect of other forms of aerosol provision system which do not rely on replaceable cartridges, for example refillable or one-time use devices.

More generally, apart from the modifications associated with the introduction of the extended channels, it will be appreciated electronic cigarettes in accordance with certain embodiments of the invention may be otherwise conventional, both in terms of structural configuration and functional operation.

Thus there has been described a vapour provision system comprising: a housing containing a reservoir of liquid; a vaporiser; and a liquid transport element arranged to transport liquid from the reservoir to the vaporiser for vaporisation, wherein the liquid transport element comprises a first portion extending into the reservoir, a second portion arranged to deliver liquid to the vaporiser, and a third portion connecting between the first portion and the second portion, wherein the third portion is arranged to pass through a channel in the housing, wherein the channel has a cross-section that matches the cross-section of the liquid transport element in the channel and a length which is at least three times the width of the liquid transport element in the channel.

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 practised. 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, and it will thus be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims. The disclosure may include other inventions not presently claimed, but which may be claimed in future.