Patent Description:
Many electronic vapour provision systems, such as e-cigarettes and other electronic nicotine delivery systems, are formed from two main components - a cartomiser and a control unit. The cartomiser generally includes a reservoir of liquid and an atomiser for vaporising the liquid. The atomiser is often implemented as an electrical (resistive) heater, such as a coil of wire. The control unit generally includes a battery for supplying power to the atomiser. In operation, the control unit may be activated, for example by detecting when a user inhales on the device and/or when the user presses a button, to provide electrical power from the battery to the heater. This activation causes the heater to vaporise a small amount of liquid from the reservoir, which is then inhaled by the user.

This type of e-cigarette therefore generally incorporates two consumables, firstly the liquid to be vaporised, and secondly power in the battery. Regarding the former, once the reservoir of liquid has been exhausted, the cartomiser may be discarded to allow replacement with a new cartomiser. Regarding the latter, the control unit may provide some form of electrical connector for receiving power from an external source, thereby allowing the battery within the e-cigarette to be re-charged.

Although e-cigarettes have developed rapidly over the past few years, there remain areas where it is desirable to improve the operability and user experience for such devices.

<CIT> relates to an aerosol generating system for heating a liquid aerosol-forming substrate, the system comprising: an aerosol-forming chamber; and a leakage prevention means configured to prevent or reduce leakage of liquid aerosol condensate from the aerosol generating system.

The disclosure is defined in the appended claims.

Some embodiments provide a cartomiser for a vapour provision system, the cartomiser including: a container for holding a reservoir of free liquid to be vaporised; an atomising chamber; a porous wick (e.g. a fibrous wick or comprising a porous solid, e.g. ceramic, material) extending from inside the container, through an aperture in a wall of the atomising chamber, to inside the atomising chamber in order to convey the liquid from the reservoir to the inside of the atomising chamber for vaporisation; and a resilient seal contained in said aperture to restrict / prevent the liquid from entering the atomising chamber from the reservoir except by travelling along the wick.

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

<FIG> is a cross-section through an e-cigarette <NUM> in accordance with some embodiments of the invention. The e-cigarette comprises two main components, namely a cartomiser <NUM> and a control unit <NUM>. As discussed in more detail below, cartomiser includes a chamber <NUM> containing a reservoir of liquid, a heater to act as an atomiser or vaporiser, and a mouthpiece. The liquid in the reservoir (sometimes referred to as the e-liquid) typically includes nicotine in an appropriate solvent, and may include further constituents, for example, to aid aerosol formation, and/or for additional flavouring. The cartomiser <NUM> further includes a wick/heater assembly <NUM>, which includes a wick or similar facility to transport a small amount of liquid from the reservoir to a heating location on or adjacent the heater. The control unit <NUM> includes a re-chargeable cell or battery <NUM> to provide power to the e-cigarette <NUM>, a printed circuit board (PCB) for generally controlling the e-cigarette (not shown in <FIG>), and a microphone <NUM> for detecting a user inhalation (via a pressure drop). When the heater receives power from the battery, as controlled by the PCB in response to the microphone <NUM> detecting a user puff on the e-cigarette <NUM>, the heater vaporises the liquid from the wick and this vapour is then inhaled by a user through the mouthpiece.

For ease of reference, the x and y axes are marked in <FIG>. The x axis will be referred to herein as the width of the device (from side to side), while the y axis will be referred to herein as the height axis, where the cartomiser <NUM> represents the upper portion of the e-cigarette <NUM> and the control unit <NUM> represents the lower portion of the e-cigarette. Note that this orientation reflects how a user holds the e-cigarette <NUM> during normal operation of the device, given that the wick is located in the lower part of the reservoir in the cartomiser <NUM>. Therefore holding the e-cigarette <NUM> in this orientation ensures that the wick is in contact with liquid at the bottom of the reservoir.

We further assume a z axis (not shown in <FIG>) which is perpendicular to the x and y axes shown in <FIG>. The z axis will be referred to herein as the depth axis. The depth of e-cigarette <NUM> is significantly less than the width of the e-cigarette, thereby resulting in a generally flat or planar configuration (in the x-y plane). Accordingly, the z axis can be considered as extending from face to face of the e-cigarette <NUM>, where one face may be regarded (arbitrarily) as the front face of the e-cigarette and the opposing face as the back face of the e-cigarette <NUM>.

The cartomiser <NUM> and the control unit <NUM> are detachable from one another by separating in a direction parallel to the y-axis, but are joined together when the device <NUM> is in use so as to provide mechanical and electrical connectivity between the cartomiser <NUM> and the control unit <NUM>. When the e-liquid in cartomiser reservoir <NUM> has been depleted, the cartomiser <NUM> is removed and a new cartomiser is attached to the control unit <NUM>. Accordingly, the cartomiser <NUM> may sometimes be referred to as the disposable portion of the e-cigarette <NUM>, while the control unit <NUM> represents the re-usable portion.

<FIG> is an isometric external view of the cartomiser of the e-cigarette of <FIG> in accordance with some embodiments of the invention. This external view confirms that the depth of the cartomiser <NUM> (and the e-cigarette <NUM> as a whole), as measured parallel to the z axis, is significantly less than the width of the cartomiser <NUM> (and the e-cigarette <NUM> as a whole), as measured parallel to the x axis. Note that overall, the external appearance of the cartomiser <NUM> is relatively smooth and uncluttered.

The cartomiser <NUM> comprises two main portions (at least from an external viewpoint). In particular, there is a lower or base portion <NUM> and an upper portion <NUM>. The upper portion <NUM> provides the mouthpiece <NUM> of the e-cigarette, as described in more detail below. When the cartomiser <NUM> is assembled with the control unit <NUM>, the base portion <NUM> of the cartomiser sits within the control unit <NUM>, and hence is not externally visible, whereas the upper portion <NUM> of the cartomiser protrudes above the control unit <NUM>, and hence is externally visible. Accordingly, the depth and width of the base portion <NUM> are smaller than the depth and width of the upper portion <NUM>, to allow the base portion to fit within the control unit <NUM>. The increase in depth and width of the upper portion <NUM> compared with the base portion <NUM> is provided by a lip or rim <NUM>. When the cartomiser <NUM> is inserted into the control unit <NUM>, this lip or rim <NUM> abuts against the top of the control unit.

As shown in <FIG>, the side wall of base portion <NUM> includes a notch or indentation <NUM> for receiving a corresponding latching member from the control unit <NUM>. The opposite side wall of the base portion <NUM> is provided with a similar notch or indentation to likewise receive a corresponding latching member from the control unit <NUM>. It will be appreciated that this pair of notches <NUM> on the base portion <NUM> (and the corresponding latching members of the control unit) provide a latch or snap fit connection for securely retaining the cartomiser <NUM> within the control unit <NUM> during operation of the device. Adjacent to the notch <NUM> is a further notch or indentation <NUM>, which is utilised in the formation of the cartomiser <NUM>, as described in more detail below.

As also shown in <FIG>, the bottom wall <NUM> of the base portion <NUM> includes two larger holes 212A, 212B on either side of a smaller hole <NUM> for air inlet. The larger holes 212A and 212B are used to provide positive and negative electrical connections from the control unit <NUM> to the cartomiser <NUM>. Thus when a user inhales through the mouthpiece <NUM> and the device <NUM> is activated, air flows into the cartomiser <NUM> through the air inlet hole <NUM>. This incoming air flows past the heater (not visible in <FIG>), which receives electrical power from the battery in the control unit <NUM> so as to vaporise liquid from the reservoir (and more especially from the wick). This vaporised liquid is then incorporated or entrained into the airflow through the cartomiser, and hence is drawn out of the cartomiser <NUM> through mouthpiece <NUM> for inhalation by the user.

<FIG> is a collection of five external views of the cartomiser <NUM> of <FIG> in accordance with some embodiments of the invention. In particular, the bottom view shows the cartomiser from underneath, the top view shows the cartomiser from above, the central view shows a face view of the cartomiser (from front or back), and on either side of the central view are respective side views of the cartomiser. Note that since the cartomiser is symmetric front/back (i.e. with respect to the z axis), the front face of the cartomiser and the back face of the cartomiser both correspond to the central view of <FIG>. In addition, the cartomiser is also symmetric in the width direction (i.e. with respect to the x axis), hence the two side views to the left and right of the central view are the same.

<FIG> illustrates the various features of the cartomiser already discussed above with respect to <FIG>. For example, the central view clearly shows the top portion <NUM> and the bottom portion <NUM> of the cartomiser. The lower view shows the bottom wall of the base portion <NUM>, including the two larger holes 212A and 212B, which are used to provide positive and negative electrical connections from the control unit <NUM> to the cartomiser <NUM>, plus the smaller hole <NUM> for air inlet into the cartomiser. In addition, the two side views show the two notches in each side wall, an upper notch 261A, 261B, and a lower notch 260A, 260B, the latter being used to fasten the cartomiser <NUM> to the control unit <NUM>.

The top view further shows a hole <NUM> in the mouthpiece <NUM> which represents the air outlet from the cartomiser <NUM>. Thus in operation, when a user inhales, air enters the cartomiser at the bottom through inlet <NUM>, flows through the atomiser, including past the heater, where it acquires vapour, and then travels up the centre of the cartomiser to exit through air outlet <NUM>.

<FIG> provides dimensions of the cartomiser <NUM>, showing a maximum height (in the y direction) of <NUM>, a maximum width (in the x direction) of <NUM>, and a maximum depth of <NUM> (parallel to the z direction). Note that these maximum width and depth measurements relate to the upper portion <NUM> of the cartomiser; the width and depth of the base portion <NUM> are somewhat smaller, in order to allow the base portion to be received into the control unit <NUM>. The difference in width and depth between the upper portion <NUM> and the base portion <NUM> is accommodated by the rim or flange <NUM>, as described above.

It will be appreciated that the dimensions shown in <FIG> are provided by way of example only, and may vary between embodiments. Nevertheless, the dimensions given do confirm that the e-cigarette <NUM>, including the cartomiser, has an approximately flat or planar shape, with one relatively small dimension (the z direction) perpendicular to the planar shape. This planar shape is extended by the control unit <NUM>, which in effect extends the height (y dimension of the cartomiser), but shares substantially the same width and depth.

<FIG> also gives a clear indication of the size and shape of the mouthpiece <NUM>. In contrast to many e-cigarettes, which provide a circular mouthpiece akin to a straw or conventional cigarette, the mouthpiece <NUM> has a very different and distinctive shape. In particular, the mouthpiece comprises a pair of large, relatively flat, opposing faces. One of these mouthpiece faces is denoted as face <NUM> in the central view of <FIG>, and there is a corresponding, opposing face to the rear of the device. (Note that the labelling of front and back for the cartomiser is arbitrary, since it is symmetric with respect to the z axis, and can be fitted either way around onto the control unit <NUM>).

The front and rear faces provide relatively large surfaces onto which the lips of a user can be placed. For example, we can consider the front face to provide a surface for engaging the upper lip, and the rear face to provide a surface for engaging the lower lip. In this configuration, we can regard the height (y axis) of the e-cigarette <NUM> defining a longitudinal axis extending away from the user's mouth, the width of the e-cigarette <NUM> (the x axis) as running parallel to the line between a user's upper and lower lips, and the depth of the e-cigarette <NUM> (the z axis) as running parallel to the direction of separation of the user's upper and lower lips.

The height of the front and rear mouthpiece faces (approximately <NUM> in the particular embodiment of <FIG>) is broadly comparable to the typical thickness of a lip, and therefore large enough to readily accommodate in this direction a lip placed on the surface. Similarly, the width of the front and rear mouthpiece faces (approximately <NUM> in the particular embodiment of <FIG>) represents a significant proportion (very approximately half) of the typical width of lips (from one side of the mouth to the other).

This shape and sizing of the mouthpiece <NUM> allows the lips of user to engage the mouthpiece for inhalation with much less distortion from the normal resting position of the mouth - e.g. there is no need to purse the lips, as for a straw or conventional cigarette having a small circular mouthpiece. This makes using the mouthpiece <NUM> of the e-cigarette <NUM> a more relaxing experience, and also may help to ensure a more consistent seal between the mouth and the mouthpiece.

In addition, e-cigarette <NUM> (like many other e-cigarettes) uses a sensor to detect airflow through the device, i.e. a user puff, which can then trigger operation of the heater to vaporise the liquid. The device has to discriminate between the airflow caused by a user puff, and other forms of airflow or pressure changes that arise due to other actions or circumstances - e.g. movement of the e-cigarette through the air, being on a railway train which enters a tunnel etc. Having a consistent seal between the mouth and the mouthpiece <NUM> can help the device provide better discrimination of an actual inhalation, and so reduce the risk of unintentional activation of the heater.

Furthermore, some e-cigarettes use sensor measurements of the airflow through the device not only to initiate activation of the heater, but also to provide dynamic control of the heater (or other components of the e-cigarette). For example, as the measured airflow increases, the heater may be provided with more power, firstly to compensate for the cooling effect of the increased airflow, and/or secondly to vaporise more liquid into the increased airflow. Having a consistent seal between the mouth and the mouthpiece <NUM> can again help to improve the reliability and accuracy of this dynamic control.

In addition, with reference to the side views of <FIG>, it can be seen that the front and back faces of the mouthpiece generally slope towards one another at the top of the device. In other words, the depth or separation of the opposing faces (as measured in the z direction) decreases towards the air outlet hole <NUM> (i.e. as the y axis increases). This slope is relatively gentle - approximately <NUM> degrees with respect to the y axis. This incline helps to provide a natural and comfortable engagement between the faces of the mouthpiece <NUM> and the lips of a user.

As can be seen in <FIG>, the front and back faces <NUM> do not converge completely at the top of the mouthpiece, but rather overhang to provide a small valley <NUM> which extends in the x-direction of the device. The opening <NUM>, which allows air and vapour to exit from the cartomiser <NUM>, is formed in the centre of this valley <NUM>. Having this small overhang, so that the mouthpiece opening <NUM> is located in the groove or valley <NUM>, helps to protect the mouthpiece opening from physical contact, and hence from potential damage and dirt.

<FIG> is an exploded view of the cartomiser <NUM> of the e-cigarette of <FIG> in accordance with some embodiments of the invention. The cartomiser includes a shell <NUM>, a vent seal <NUM>, an inner frame <NUM>, a heating coil <NUM> located on a wick <NUM>, a primary seal <NUM> (also referred to as the cartomiser plug), a printed circuit board (PCB) <NUM> and an end cap <NUM>. The view of <FIG> shows the above components exploded along the longitudinal (height or y) axis of the cartomiser <NUM>.

The cap <NUM> is formed from substantially rigid plastic such as polypropylene and provides the base portion <NUM> of the cartomiser. The cap is provided with two holes <NUM>, <NUM> on each side (only one side is visible in <FIG>, but the side which is not visible is the same as the side that is visible). The lower hole <NUM> is for latching the cartomiser <NUM> to the control unit <NUM>, while the upper hole <NUM> is for latching the end cap <NUM> to the shell <NUM>. As described in more detail below, latching the cap <NUM> and the shell <NUM> in effect completes the assembly of the cartomiser, and retains the various components shown in <FIG> in the correct position.

Above the end cap is located the PCB <NUM>, which includes a central air hole <NUM> to allow air to flow through the PCB into the atomiser (the end cap <NUM> is likewise provided with a central air hole, not visible in <FIG>) to support this air flow into the atomiser. In accordance with some embodiments, the PCB does not contain any active electrical components, but rather provides a circuit or conductive path between the control unit <NUM> and the heater <NUM>.

Above the PCB <NUM> is located the primary seal <NUM>, which has two main portions, an upper portion which defines (in part) an atomizer chamber <NUM>, and a lower portion <NUM> which acts as an end seal for the reservoir <NUM>. Note that in the assembled cartomiser <NUM>, the reservoir of e-liquid is located around the outside of the atomizer chamber, and the e-liquid is prevented from leaving the cartomiser (at least in part) by the lower portion <NUM> of the cartomiser plug <NUM>. The cartomiser plug is made from a material that is slightly deformable. This allows the lower portion <NUM> to be compressed a little when inserted into the shell <NUM>, and hence provide a good seal to retain the e-liquid in reservoir <NUM>.

Two opposing side walls of the atomiser chamber <NUM> are provided with respective slots <NUM> into which the wick <NUM> is inserted. This configuration thereby ensures that the heater <NUM>, which is positioned on the wick, is located near the bottom of the atomiser chamber to vaporise liquid introduced into the atomiser chamber <NUM> by wick <NUM>. In some embodiments, the wick <NUM> is made of glass fibre rope (i.e. filaments or strands of glass fibre twisted together), and the heater coil <NUM> is made of nichrome (an alloy of nickel and chromium). However, various other types of wick and heater are known and could be used in the cartomiser <NUM>, such as a wick made out of porous ceramic, and/or some form of planar heater (rather than a coil). Note that although <FIG> suggests that the heater coil <NUM> has a loop of wire dropping down from the wick at each end, in practice there is just a single lead at each end (as described in more detail below).

The cartomiser plug <NUM> and the wick/heater assembly are surmounted by the inner frame <NUM>, which has three main sections. The inner frame is substantially rigid, and may be made of a material such as polybutylene terephthalate. The lowermost section <NUM> of the inner frame <NUM> covers the lower portion <NUM> of the cartomiser plug <NUM>, while the middle section <NUM> completes the atomiser chamber <NUM> of the cartomiser plug. In particular, the inner frame provides the top wall of the atomiser chamber, and also two side walls that overlap with the two side walls of the atomising chamber <NUM> of the cartomiser plug. The final section of the inner frame is an airflow tube <NUM> that leads upwards from the top wall of the atomising chamber (part of the middle section <NUM>) and connects with the mouthpiece hole <NUM>. In other words, tube <NUM> provides a passage for vapour produced in the atomising chamber <NUM> to be drawn out of the e-cigarette <NUM> and inhaled through mouthpiece <NUM>.

Since the inner frame is substantially rigid, the vent seal <NUM> is provided at (inserted around) the top of the airflow tube <NUM> to ensure a proper seal between the inner frame and the mouthpiece exit hole <NUM>. The vent seal <NUM> is made of a suitably deformable and resilient material such as silicone. Lastly, the shell <NUM> provides the external surface of the upper portion <NUM> of the cartomiser <NUM>, including the mouthpiece <NUM>, and also the lip or flange <NUM>. The shell <NUM>, like the end cap, is formed of a substantially rigid material, such as polypropylene. The lower section <NUM> of the shell <NUM> (i.e. below the lip <NUM>) sits inside the end cap <NUM> when the cartomiser has been assembled. The shell is provided with a latch tab <NUM> on each side to engage with hole <NUM> on each side of the end cap <NUM>, thereby retaining the cartomiser <NUM> in its assembled condition.

In the example shown in <FIG>, the top surface of the latch tab <NUM> is horizontal - i.e. in the x-z plane, perpendicular to the wall of the shell <NUM>. In some implementations, this top surface of latch tab <NUM> slopes downwards and inwards towards the shell <NUM>, for example at an angle of up to <NUM> degrees to the horizontal - e.g. at an angle of <NUM> degrees. This slope can help to give more secure latching between the shell <NUM> and the end cap <NUM>.

The airflow passage through the cartomiser enters a central hole in the cap <NUM> (not visible in <FIG>) and then passes through a hole <NUM> in the PCB. The airflow next passes up into the atomiser chamber <NUM>, which is formed as part of the cartomiser plug <NUM>, flows around the wick and heater assembly <NUM> and through the tube <NUM> of the inner frame <NUM> (and through vent seal <NUM>), and finally exits through the hole <NUM> in the mouthpiece <NUM>.

The reservoir <NUM> of e-liquid is contained in the space between this airflow passage and the outer surface of the cartomiser <NUM>. Thus shell <NUM> provides the outer walls (and top) of the housing for the reservoir <NUM>, while the lower section <NUM> of the inner frame in conjunction with the base portion <NUM> of the primary seal <NUM> and end cap <NUM> provide the bottom or floor of the housing for the reservoir of e-liquid. The inner walls of this housing are provided by the atomising chamber <NUM> of the primary seal <NUM>, in cooperation with the middle section <NUM> of the inner frame, and also the airflow tube <NUM> of the inner frame <NUM> and the vent seal <NUM>. In other words, the e-liquid is stored in the reservoir space between the outer walls and the inner walls. However, the e-liquid should not penetrate inside the inner walls, into the airflow passage, except via wick <NUM>, otherwise there is a risk that liquid would leak out of the mouthpiece hole <NUM>.

The capacity of this space is typically of the order of <NUM> in accordance with some embodiments, although it will be appreciated that this capacity will vary according to the particular features of any given design. Note that unlike for some e-cigarettes, the e-liquid reservoir <NUM> is not provided with any absorbent material (such as cotton, sponge, foam, etc) for holding the e-liquid. Rather, the reservoir chamber only contains the liquid, so that the liquid can move freely around the reservoir <NUM>. This has certain advantages, such as generally supporting a larger capacity, and also making the filling procedure less complex. One potential disadvantage with having a free liquid in the reservoir (i.e. not holding the liquid in a sponge or other absorbent structure) is that the liquid can flow more easily, and hence might be more likely to leak in an undesirable manner from the reservoir <NUM> into the airflow passage. However, such leakage is generally prevented by the vent seal <NUM> and the primary seal <NUM>.

<FIG> illustrate the wick/heater assembly being fitted into the cartomiser plug in accordance with some embodiments of the invention. The wick/heater assembly <NUM> is formed from the heater wire <NUM> and the wick <NUM>. As noted above, the wick comprises glass fibres formed into a generally cylindrical or rod shape. The heater <NUM> comprises a coil of wire <NUM> wound around the wick. At each end of the coil there is a contact wire 552A, 552B, which together act as the positive and negative terminals to allow the coil to receive electrical power.

As visible in <FIG>, the primary seal <NUM> includes the base portion <NUM> and the atomising chamber <NUM>. The base portion is provided with two outwardly directed ribs. When the shell <NUM> is fitted over the base portion, these ribs are compressed slightly in order to fit inside the shell <NUM>. This compression and the resulting slight resilient deformation of the ribs helps to ensure a good seal for the e-liquid at the base of the cartomiser reservoir.

Also visible in <FIG>, the atomising chamber <NUM> comprises four walls in a rectangular arrangement, a pair of opposing side walls <NUM>, and a pair of opposing front and back walls <NUM>. Each of the opposing side walls <NUM> includes a slot <NUM> which has an open end at the top (and in the centre) of the side wall, and a closed end <NUM> relatively near the bottom of the atomising chamber <NUM> - i.e. the two slots <NUM> extend more than halfway down their respective side walls <NUM>.

Referring now to <FIG>, this shows the wick/heater assembly <NUM> now fitted into the atomising chamber <NUM> of the cartomiser plug. In particular, the wick/heater assembly is positioned so that it extends between, and protrudes out of, the two opposing slots 569A, 569B. The wick is then lowered until it reaches the closed end <NUM> of each slot. Note that in this position, the coil <NUM> is located entirely in the atomizing chamber <NUM> - it is only the wick itself <NUM> that extends out of the slots into the reservoir area <NUM>. It will be appreciated that this arrangement allows the wick to draw e-liquid from the reservoir <NUM> into the atomizing chamber <NUM> for vaporisation by the wire heater coil <NUM>. Having the wick located near the bottom of the atomizing chamber, and more particularly also near the bottom of the reservoir <NUM>, helps to ensure that the wick retains access to liquid in the reservoir even as the e-liquid is consumed, and hence the level of the e-liquid in the reservoir drops. <FIG> also shows the heater contact wires 552A, 552B extending below the primary seal <NUM>.

<FIG> illustrates the underside of the base portion <NUM> of the primary seal <NUM>. This view shows that the base portion includes two holes 582A, 582B, which are used for filing the reservoir <NUM> with e-liquid, as described in more detail below. The underside further includes a rectangular indentation <NUM> for receiving the PCB <NUM>. A central hole <NUM> is provided in this indentation <NUM> to provide an air passage from underneath (and outside) the cartomiser into the atomisation (vaporisation) chamber <NUM>. It will be appreciated that after assembly, this central hole <NUM> in the cartomiser plug is aligned with the corresponding central hole <NUM> in the PCB.

There are also two much smaller holes 587A, 587B formed in the rectangular indentation <NUM> of the lower portion of the cartomiser plug <NUM>, one on either side of the central hole <NUM>. The contact wires 552A and 552B extend downwards from the heater <NUM> and pass respectively through these two holes, 587A, 587B, in order to exit the vaporising chamber <NUM>.

A slit 590A, 590B is formed in each of the front and back walls of the rectangular indentation <NUM>. After extending through the two holes 587A, 587B, each contact wire from the heater is bent flat onto the underside of the cartomiser plug, and then leaves the rectangular indentation via the respective slits 590A, 590B. Thus contact wire 552A passes out of the atomising chamber <NUM> through hole 587A, and then exits the rectangular indentation <NUM> via slot 590A; likewise, contact wire 552B passes out of the atomising chamber <NUM> through hole 587B, and then exits the rectangular indentation <NUM> via slot 590B. The remaining portion of each wire 552A, 552B is then bent upwards towards the atomising chamber <NUM> in order to sit within a respective groove <NUM> in the cartomiser plug <NUM> (see <FIG>). In some examples there may not be respective grooves <NUM> in the cartomiser plug <NUM> and the remaining portions of the each wire 552A, 552B may instead be simply bent to run alongside the side of cartomiser plug <NUM>.

<FIG> illustrate the inner frame and the vent seal being fitted into the cartomiser plug in accordance with some embodiments of the invention. Thus as previously described, the inner frame <NUM> comprises a base section <NUM>, a middle section <NUM> and air tube <NUM> located at the top of the inner frame. The base section contains two slots 671A, 671B extending in a horizontal sideways direction (parallel to the x axis). As the base section <NUM> of the inner frame is lowered down past the atomizing chamber <NUM>, the portions of the wick <NUM> that extend out from each side of the atomizing chamber <NUM> pass through these slots 671A, 671B, thereby allowing the base section of the inner frame to be lowered further until it is received in the lower portion <NUM> of the cartomiser plug.

As noted above, the middle section <NUM> of the inner frame complements and completes the atomizing chamber <NUM> of the cartomiser plug <NUM>. In particular, the middle section provides two opposing side walls <NUM> and a top wall or roof <NUM>. The latter closes the top of the atomizing chamber <NUM>, except in respect of the air tube <NUM> which extends up from the atomizing chamber <NUM> to the exit hole <NUM> of the mouthpiece <NUM>.

Each of the opposing side walls <NUM> includes a slot 669A, 669B which extends upwards (parallel to the y axis) from the bottom of the side wall to the closed end of the respective slot. Accordingly, as the base section <NUM> of the inner frame is lowered down past the atomizing chamber <NUM>, the portions of the wick <NUM> that extend out from each side of the atomizing chamber <NUM> pass through these slots 669A, 669B (in addition to slots 671A, 671B). This therefore allows the side walls <NUM> of the inner frame <NUM> to overlap the side walls <NUM> of the cartomiser plug. Further downward movement of the inner frame <NUM> is prevented once the closed end of slots 669A, 669B contacts the wick <NUM>, which coincides with the base section <NUM> of the inner frame being received into the lower portion <NUM> of the cartomiser plug. At this stage, the combination of cartomiser plug <NUM>, heater/wick assembly <NUM>, and inner frame <NUM>, as shown in <FIG> has been formed, and the vent seal <NUM> can now be fitted onto the air tube (pipe) <NUM> of the inner frame <NUM>.

<FIG> illustrates the combination of the inner frame <NUM>, wick/heater assembly <NUM>, and primary seal <NUM> being fitted into the shell <NUM>. As this insertion occurs, the slot <NUM> in each of the front and back faces of the lower portion <NUM> of the shell <NUM> accommodates a portion of wire <NUM> that has passed through slot <NUM> and has been wrapped back up around the outside of the cartomiser plug <NUM> and into groove <NUM>. Furthermore, the deformable ribs <NUM> around the lower portion <NUM> of the primary seal are slightly compressed by the inside wall of the lower portion <NUM> of the shell <NUM> during the insertion, and thereby form a seal to retain the e-liquid in the resulting reservoir <NUM>. Accordingly, as illustrated in <FIG>, the cartomiser <NUM> is now ready for filling with the e-liquid. This filling is performed, as indicated by arrows 701A, 701B, through holes 582A and 582B in the primary seal <NUM>, and through slots 671A, 671B in the inner frame (not visible in <FIG>).

<FIG> illustrates the PCB <NUM> being fitted into the rectangular indentation <NUM> in the underside of the primary seal <NUM>. This fitting aligns the central hole <NUM> in the PCB with the central hole <NUM> in the primary seal <NUM> in order to provide the main airflow channel into the cartomiser <NUM>.

As previously described, the rectangular indentation <NUM> is provided with a pair of holes <NUM>, located on either side of the central hole <NUM>. Each hole allows egress of a respective contact wire 552A, 552B from the vaporiser chamber <NUM>. The contact wires 552A, 552B are bent flat against the floor of the rectangular indentation <NUM>, and then exit the rectangular indentation <NUM> via respective slots 590A, 590B in the front and back walls of the rectangular indentation. The final portion of each heater contact wire 552A, 552B, is then bent upwards, back towards the top of the cartomiser and mouthpiece <NUM>, and located in a corresponding groove or channel <NUM> formed in the cartomiser plug. In addition, the base portion of the shell also includes a slot <NUM> on each of the front and back faces to accommodate a respective heater contact wire 552A, 552B.

In accordance with some embodiments, the PCB <NUM> does not contain any active components, but rather provides two large contact pads 810A, 810B on either side of the central hole <NUM>. These contact pads are visible in <FIG> on the lower face of the PCB, i.e. the side facing the control unit <NUM> after assembly. The opposite face of the PCB, i.e. the upper side which is received into the rectangular indentation <NUM> and faces the heater <NUM>, is provided with a similar, corresponding configuration of contact pads (not visible in <FIG>). The heater contact wires 552A, 552B are in physical, and hence electrical, contact with a respective contact pad on the upper side of the PCB.

The opposing pairs of contact pads on either side of the PCB <NUM> are connected by respective sets of one or more vias 820A, 820B. In other words, vias 820A provide a conductive path between one contact pad on the lower face of the PCB and a corresponding contact pad on the upper face of the PCB, and vias 820B provide a conductive path between the other contact pad on the lower face of the PCB and its corresponding contact pad on the upper face of the PCB. Accordingly, when the control unit is connected to the cartomiser, pins from the control unit touch the contact pads on the lower side of the PCB <NUM>, and electrical current flows to/from the heater <NUM> through the respective vias, contact pads on the upper side of the PCB <NUM>, and respective heater contact wires 552A, 552B.

<FIG> illustrates the end cap <NUM> being fitted to the cartomiser <NUM> in accordance with some embodiments of the invention. In particular, the end cap <NUM> is fitted over the end of the cartomiser plug <NUM> and the lower section <NUM> of the shell <NUM>, and is retained in this position by the protruding member <NUM> provided on each side of the lower section <NUM> of the shell engaging into the corresponding hole or slot <NUM> on each side of the end cap. In this fully assembled state (see <FIG>), the end cap <NUM> covers and therefore closes the holes 582A, 582B in the cartomiser plug that were used for filling the liquid reservoir <NUM>. Indeed, as can be seen in <FIG>, the end cap <NUM> is provided with two upwardly directed plugs 870A and 870B that respectively penetrate and close the filling holes 582A, 582B. Accordingly, the reservoir <NUM> is now fully sealed, apart from the opening on each side of the atomising chamber <NUM> through which the wick <NUM> passes into the atomising chamber <NUM>.

As previously discussed, the end cap includes three holes, a central hole <NUM> and two holes 212A, 212B located on either side of this central hole. The fitting of the end cap <NUM> aligns the central hole <NUM> of the end cap with the central hole <NUM> in the PCB and with the central hole <NUM> in the primary seal <NUM> in order to provide the main airflow channel into the cartomiser <NUM>. The two side holes 212A, 212B allow pins from the control unit <NUM>, acting as positive and negative terminals, to pass through the end cap <NUM> and make contact with respective contact pads 810A, 810B on the lower side of the PCB, thereby enabling the battery <NUM> in the control unit <NUM> to supply power to the heater <NUM>.

In accordance with some embodiments, the primary seal <NUM>, which as noted above is made of a resilient deformable material such as silicone, is held in a compressed state between the inner frame <NUM> and the end cap <NUM>. In other words, the end cap is pushed onto the cartomiser <NUM> and compresses the primary seal <NUM> slightly before the latch components <NUM> and <NUM> engage with one another. Consequently, the primary seal remains in this slightly compressed state after the end cap <NUM> and shell <NUM> are latched together. One advantage of this compression is that the end cap acts to push the PCB <NUM> onto the heater contact wires 552A, 550B, thereby helping to ensure a good electrical connection without the use of solder.

<FIG> is a top view looking down onto the control unit <NUM> of the e-cigarette of <FIG> in accordance with some embodiments of the invention. The control unit includes external walls <NUM> that rise above the rest of the control unit (as best seen in <FIG>) to define a cavity for accommodating the lower portion <NUM> of the cartomiser. Each side of these walls <NUM> is provided with a spring clip 931A, 931B that engages with the hole or slot <NUM> on each side of the cartomiser <NUM> (see <FIG>), thereby retaining the cartomiser in engagement with the control unit <NUM> to form the assembled e-cigarette <NUM>.

At the bottom of the cavity formed by the upper portion of control unit walls <NUM> (but otherwise at the top of the main body of the control unit <NUM>) is a battery seal <NUM> (see also <FIG>). The battery seal <NUM> is formed from a resilient (and compressible) material such as silicone. The battery seal <NUM> helps to mitigate one potential risk with an e-cigarette <NUM>, which is that e-liquid leaks from the reservoir <NUM> into the main air passage through the device (this risk is greater where there is free liquid in the reservoir, rather than the liquid being held by a foam or other such material). In particular, if e-liquid were able to leak into the portion of the control unit containing the battery <NUM> and control electronics, then this might short circuit or corrode such components. Furthermore, there is also a risk that the e-liquid itself would then become contaminated before returning into the cartomiser <NUM> and then exiting through the mouthpiece hole <NUM>. Accordingly, if any e-liquid does leak into the central air passage of the cartomiser, the battery seal <NUM> helps to prevent such leakage progressing into the portion of the control unit that contains the battery <NUM> and control electronics. (The small holes <NUM> in the battery seal <NUM> do provide very limited fluid communication with the microphone <NUM> or other sensor device, but the microphone <NUM> itself can then act as a barrier against any such leakage progressing further into the control unit.

As shown in <FIG>, there is a small groove or spacing <NUM> around the perimeter between the top of the battery seal <NUM> and the inside of the walls <NUM> of the control unit; this is primarily formed by the rounded corner of the battery seal <NUM>. The battery seal is further provided with a central groove <NUM> from front to back, which connects at both ends (front and back) with the perimeter groove <NUM> to support airflow into the cartomiser, as described in more detail below. Immediately adjacent to central groove <NUM> are two holes 908A, 908B, one on either side of the groove <NUM>. These air holes extend down to the microphone <NUM>. Thus when a user inhales, this causes a drop in pressure within the central air passage through the cartomiser <NUM>, as defined by air tube <NUM>, the central hole <NUM> in the primary seal <NUM>, etc, and also within the central groove <NUM>, which lies at the end of this central air passage. The drop in pressure further extends through holes 908A, 908B to the microphone <NUM>, which detects the drop in pressure, and this detection is then used to trigger activation of the heater <NUM>.

Also shown in <FIG> are two contact pins, 912A, 912B, which are linked to the positive and negative terminals of the battery <NUM>. These contact pins 912A, 912B pass through respective holes in the battery seal <NUM> and extend through holes 212A, 212B of the end cap to make contact with contact pads 810A, 810B respectively on the PCB. Accordingly, this then provides an electrical circuit for supplying electrical power to the heater <NUM>. The contact pins may be resiliently mounted within the battery seal (sometimes referred to as "pogo pins"), such that the mounting is under compression when the cartomiser <NUM> is latched to the control unit <NUM>. This compression causes the mounting to press the contact pins against the PCB contact pads 810A, 810B, thereby helping to ensure good electrical connectivity. It will be appreciated that approaches other than using pogo pins could be used. For example, in some cases the contact pins may not be spring mounted, but may instead accommodate a degree of resilient deflection when assembled to facilitate a biased contract with the PCB contact pads. In another cases, the contact pins may themselves be rigid and carried by a resiliently mounted support.

The battery seal <NUM>, which as noted above is made of a resilient deformable material such as silicone, is held in a compressed state between the cartomiser <NUM> and the control unit <NUM>. In other words, inserting the cartomiser into the cavity formed by walls <NUM> causes the end cap <NUM> of the cartomiser to compress the battery seal <NUM> slightly before the spring clips 931A, 931B of the control unit engage with the corresponding holes 260A, 260B in the lower portion <NUM> of the cartomiser. Consequently, the battery seal <NUM> remains in this slightly compressed state after the cartomiser <NUM> and the control unit <NUM> are latched together, which helps to provide protection against any leakage of e-liquid, as discussed above.

<FIG> are cross-sections respectively (a) from side to side, and (b) from front to back, showing the airflow through the e-cigarette of <FIG> in accordance with some embodiments of the invention. The airflow is denoted in <FIG> by the heavy black, dashed arrows. (Note that <FIG> only shows air flow on one side of the device, but there is an analogous air flow on the other side as well - having multiple such air inlets reduces the risk that a user will accidentally block the air inlets with their fingers while holding the device).

The airflow enters through a gap at the sides of the e-cigarette <NUM>, in between the top of the walls <NUM> of the control unit, and the flange or rim <NUM> of the cartomiser shell <NUM>. The airflow then passes down a slight spacing between the inside of the walls <NUM> and the outside of the lower portion <NUM> of the cartomiser <NUM>, past the spring clips <NUM>, and hence into perimeter groove <NUM> (as shown in <FIG>). The airflow is then drawn around the perimeter groove <NUM>, and hence out of the plane of <FIG> (so that this portion of the airflow path is therefore not visible in these two diagrams). Note that there is typically some space above the groove <NUM> between the inside of the control unit walls and the outside of the cartomiser end cap, so the airflow is not necessarily constrained to the groove <NUM> per se.

After travelling an angle of approximately <NUM> degrees around the perimeter groove <NUM>, the airflow passes into the central groove <NUM>, from where it travels to and through the central hole <NUM> of the end cap <NUM> and hence into the central air passage of the cartomiser. Note that <FIG> shows this airflow along the central groove <NUM> into the central air passage, and then the flow of air up through the central air passage is shown in both <FIG>. In contrast to groove <NUM>, the space above groove <NUM> is not open, but rather the battery seal <NUM> is compressed against the end cap <NUM> of the cartomiser <NUM>. This configuration results in the end cap covering the groove to form a closed channel having a confined space. This confined channel can be utilised to help control the draw resistance of the e-cigarette <NUM>, as described in more detail below.

There are various benefits associated with the overall airflow path such as shown in <FIG>. The airflow detector, such as microphone <NUM>, is generally located in the control unit <NUM>. This reduces cost because the microphone is therefore in the reusable portion of the device, and so there is no need to include a microphone in every cartomiser (the disposable component). In addition, having the microphone <NUM> in the control unit <NUM> allows the microphone to be readily connected to the battery <NUM> and to the control processor of the control unit (not shown in the Figures).

On the other hand, it is generally desirable to reduce or avoid an airflow past electronics components, for example, because such electronics components tend to become warm with use, and may potentially shed volatiles. It will be appreciated that the airflow path shown in <FIG> largely bypasses the electronic components of the control unit, with only the small holes <NUM> branching off this main airflow to allow the microphone <NUM> to detect a change in pressure. This avoidance of airflow past the main electronic components of the control unit has been achieved despite the fact that the cartomiser sits quite deeply within the control unit (which helps to reduce the overall length of the device).

Furthermore, in many existing e-cigarettes, the overall air path is not tightly controlled. For example, air may leak into the air path at joins between various components (such as between the cartomiser and control unit), rather than just at the dedicated air inlet(s). This leakage (as well as various other manufacturing variations) may result in significant variation in the draw resistance of the device, where the draw resistance in effect represents the pressure difference needed to produce a given air flow through the device. This variation in draw resistance can prevent a consistent user experience and can also effect the operation of the device. For example, if the draw resistance is high, it is likely that the flow of air through the device may be reduced, which in turn reduces the amount of air cooling experienced by the heater.

Accordingly, the approach described herein provides an e-cigarette device including: an atomiser for vaporising a liquid; an air passage through the atomiser, the air passage exiting the e-cigarette at a mouthpiece; at least one air inlet joined by a channel to the air passage through the vaporiser; and at least one resilient seal which acts to prevent air from the air inlet travelling to the air passage except through the channel.

For example, in the implementation described above, the air flow entering the central air passage through the vaporiser must first travel along groove <NUM>. This groove, in conjunction with the bottom of the end cap <NUM> that in effect provides a top surface or closure for the groove, defines the airflow channel through the control unit into the cartomiser.

In such a device, air from the air inlet must necessarily travel through the channel to reach the air passage (because the seal prevents other routes). Accordingly, the channel provides a point of control for the draw resistance - especially if the channel provides the majority of the draw resistance for the air path through the whole device. In particular, as long as the draw resistance for the channel (which is determined largely by the size of the channel) is reasonably constant between devices (and between different usages of the same device), then the draw resistance for the device as a whole will likewise be reasonably constant.

In some implementations, the e-cigarette may further comprise a facility to alter the predetermined draw resistance for the e-cigarette. This facility may allow a user to set the predetermined draw resistance for the e-cigarette to one of a limited number of discrete values according to individual preference, etc. For example, for the e-cigarette described herein, there may be two successive latch positions between the cartomiser <NUM> and the control unit <NUM>, which result in a lower or greater compression of the battery seal <NUM>. The lower compression will generally allow groove <NUM> to expand slightly, and hence provide a lower draw resistance than the latch position which produces the higher compression of the battery seal. Another way of implementing this facility would be to provide some baffle that can be moved into the channel or groove <NUM> to partly obstruct the airflow by a desired amount.

The seal may be formed of a resilient material, such as silicone, and the channel is formed at least in part by the seal material itself. For example, in some embodiments, the channel is defined by a resilient material compressed against a surface of a rigid material, such as the battery seal <NUM> pressing against the end cap <NUM>, and the surface of the rigid material may include a hole, such as hole <NUM> in end cap <NUM>, that connects from the channel <NUM> into the air passage through the atomiser. Note that the channel may in fact comprises a network of multiple (sub)channels as appropriate, according to the particular implementation.

As described above, the device may include a cartomiser <NUM> and a control unit <NUM>, and the resilient seal is provided as part of the control unit that contacts the exterior of the cartomiser when the cartomiser is joined to the control unit. The resilient material may be held under compression between the cartomiser and the control unit when the cartomiser is joined to the control unit, such as by a latch mechanism. This compression of the resilient material helps to provide an air-tight seal around the edges of the seal.

A further consideration is that for some e-cigarettes, there is a risk that the e-liquid may leak <NUM> into main air passage. In such a situation, the seal helps to ensure that the e-liquid is only able to travel from the air passage into the air channel, thereby helping to prevent the e-liquid coming into contact with the battery and other electrical components. Furthermore, the air channel may be sufficiently narrow to prevent significant flow of e-liquid through the channel, which further helps to constrain any leaked e-liquid.

<FIG> are a side view and a perspective view respectively of another implementation of the cartomiser plug or primary seal in accordance with some embodiments of the invention. The cartomiser plug 460A shown in these Figures can be used, if so desired, as a replacement for the cartomiser plug <NUM> previously described. The cartomiser plug 460A is further illustrated in <FIG>, which provides a detailed view of a portion of the cartomiser plug 460A of <FIG> in accordance with some embodiments of the invention, and also in <FIG>, which is a perspective view of the cartomiser plug 460A of <FIG> assembled with a wick in accordance with some embodiments of the invention.

Cartomiser plug 460A shares many features with the cartomiser plug <NUM> previously described, including: a base portion <NUM> with ribs 563A, 563B and grooves <NUM> for the upturned heater contact wires; and an atomising chamber <NUM> with front and back walls <NUM>, side walls <NUM>, and slots 569A, 569B for receiving wick <NUM>. The cartomiser plug 460A differs from cartomiser plug <NUM> in three main aspects.

Firstly, the shape of the slots <NUM> has been modified slightly, in that the slots no longer have parallel sides or edges descending to a U-shaped closed end, such as shown in <FIG>. Rather, each slot now comprises two portions, a stem portion <NUM> that leads downwards from the open end of the slot to a wick retaining portion <NUM> located at the closed end of the slot. The sides or edges of the stem portion <NUM> are no longer parallel, but rather open out towards to the top of the slot <NUM>, i.e. towards the open end of the slot. It will be appreciated that this opening out of portion stem <NUM> helps to allow the wick <NUM> to be inserted into the slot <NUM> more easily. Conversely, the sides or edges of the stem portion <NUM> approach one another in the depth direction towards the closed end of the slot <NUM>. Typically therefore, the wick <NUM> will be slightly compressed by this narrowing stem <NUM> (in a direction perpendicular to the main longitudinal axis of the wick) as the wick <NUM> is inserted down the slot <NUM>.

At the closed end of the slot is the wick retaining portion <NUM>, which forms a curved aperture. The curvature of the wick retaining portion <NUM> slightly exceeds a total of <NUM> degrees, hence the slot <NUM> has in effect a narrowed region or neck where the wick retaining portion <NUM> joins the stem portion <NUM>. It will be appreciated that this configuration of the slot <NUM>, including the wick retaining portion <NUM> with the neck of reduced thickness, helps to maintain the wick <NUM> in the correct position at the closed, bottom end of the slot <NUM>, since the wick <NUM> would generally have to be compressed again in order to pass back upwards through the neck above the wick retaining portion <NUM>.

A second difference between the cartomiser plug 460A and the cartomiser plug <NUM> is that for the former, the inner walls or edges of the slot <NUM> are provided with a lip seal <NUM>. In particular, this lip seal <NUM> comprises a slight ridge that protrudes from the inner walls of the slot <NUM>, and hence is directed inwardly with respect to the slot itself. The ridge runs down both sides of the stem portion <NUM> of the slot <NUM>, and also runs around the curved inner surface of the wick retaining portion <NUM>.

The lip seal is made of a resilient material, such as silicone, and when the wick is inserted into the slot <NUM>, the lip seal <NUM> is compressed and/or deflected sideways (in effect, bent over) in order to accommodate the wick. In this compressed or deflected state, the lip seal is therefore biased against the wick <NUM>. This helps to provide a more effective seal between the reservoir <NUM> and the atomising chamber <NUM>, in that there is no space between the lip seal <NUM> and the wick <NUM> for liquid to flow directly from the reservoir <NUM> into the atomising chamber <NUM>. Rather, any transfer of e-liquid from the reservoir <NUM> into the atomising chamber must occur in a controlled manner via the wick <NUM>, whereby the material of the wick itself constrains such flow. In particular, the wick <NUM> holds the liquid in the atomising chamber <NUM> until this liquid is vaporised by the heater <NUM>, in which case the wick <NUM> will draw replacement e-liquid into the atomising chamber from reservoir <NUM>. Such a configuration therefore helps to reduce the risk of free liquid being leaked into the main airflow passage of the e-cigarette <NUM>.

Note that the wick <NUM> itself is compressible to some extent, since it is formed of multiple glass fibres (or other fibrous material). If a very tight seal were to be formed around the wick, such that the wick and fibres are tightly compressed, such a tight seal might well be effective as a seal, but it would also degrade the performance of the wick, making it much harder for the wick to transport e-liquid from the reservoir <NUM> into the atomising chamber. The resilience of the lip seal <NUM> is therefore arranged to ensure that the bias force resulting from the compression or deflection of the lip seal has comparatively little effect on the wick, and so does not impact the performance of the latter as regards transporting liquid into the atomizing chamber for vaporisation. For example, if the lip seal is relatively thin, then it can be deflected by the wick with relatively little reaction force being created back onto the wick.

Although the lip seal of cartomiser 460A is formed from a single ridge, it will be appreciated that in some implementations multiple ridges may be utilised instead. Furthermore a lip seal could also be provided if so desired in the corresponding slots 669A, 669B of the inner frame and/or on pedestal <NUM> (instead of or in additional to the lip seal <NUM> in slots <NUM>).

A third difference between the cartomiser plug 460A and the cartomiser plug <NUM> is that for the former, a pedestal <NUM> is provided adjacent each side wall <NUM>, outside the atomising chamber. When the wick <NUM> is inserted into the slots <NUM>, and in particular, with the wick located in the wick retaining portion <NUM> of the slots <NUM>, the wick <NUM> rests on surface <NUM> located at the top of each pedestal <NUM>. Supporting the wick in this manner at each end by the pedestals <NUM> helps to avoid distortion of the wick, either caused by the weight of the end regions of the wick itself, and/or by the inner frame <NUM> pressing down on the wick <NUM>, for example as part of the assembly step shown in <FIG>. The prevention of such distortion of the wick <NUM> generally helps to maintain an appropriate and consistent flow of e-liquid into the atomizing chamber, and also helps to reduce the risk of liquid leakage that might otherwise occur from such distortion of the wick <NUM>.

Although various embodiments have been described in detail herein, this is by way of example only, it will be appreciated that a channel to constrain airflow into a device may be utilised in many different configurations. For example, this approach might be used for a one-piece or three-piece device (rather than a two-piece device, i.e. cartomiser and control unit, as described here). Similarly, this approach could be utilised with electronic vapour provision systems that includes material derived from tobacco plants which is provided in any suitable form (powder, paste, shredded leaf material, etc, i.e. not liquid), and then heated to produce volatiles for inhalation by a user. This approach could also be used with various types of heater for the e-cigarette, various types of airflow configuration, various types of connection between the cartomiser and the control unit (such as screw or bayonet) etc. The skilled person will be aware of various other forms of electronic vapour provision system which might utilise a channel for restricting the airflow as described herein.

Furthermore, it will be appreciated the manner of cartomiser assembly set out above is merely one example, and an assembly process comprising different steps, or a similar steps performed in a different order may also be adopted. For example, with reference to the steps set out in relation to <FIG>, <FIG>, in another example instead of fitting the vent seal <NUM> to the air tube (pipe) <NUM> of the inner frame (<FIG>) before placing the combined assembly in the shell <NUM> (<FIG>), the vent seal <NUM> might first be mounted in position in the shell <NUM> so that it mounts to the air tube (pipe) <NUM> of the inner frame when the inner frame <NUM>, wick/heater assembly <NUM>, and primary seal <NUM> are together fitted into the shell <NUM>. Similarly, with reference to the steps set out in relation to <FIG>, in another example instead of placing the PCB <NUM> in its indentation <NUM> in the cartomiser plug <NUM> before attaching the cap <NUM> to complete the cartomiser assembly, the PCB <NUM> might first be mounted in position in the cap <NUM>, and then the cap <NUM>, with PCB <NUM> attached, connected to the shell <NUM>. The PCB <NUM> may mount to the cap <NUM> by a friction / press fit, for example. The cap may include locating pegs, or other guide mechanism, to help position the PCB in the cap so it is aligned with the indentation <NUM> in the cartomiser plug when the cap is attached to the shell.

<FIG> onwards (through to <FIG>) illustrate a further variation on certain aspects of the cartomiser described above. The implementation of <FIG> onwards generally comprises the same components as the implementation shown in <FIG> (for example), but there are some slightly changes to the individual components. For ease of reference, components in <FIG> onwards are given the same reference number as in the previous Figures, but preceded by a "<NUM>", so that (for example) the vent seal of <FIG> has reference numeral <NUM>, while the vent seal of <FIG> has reference numeral <NUM>. Note that corresponding components, such as the vent seal <NUM> and the vent seal <NUM>, generally have the same structure, material, functionality, etc as each other unless otherwise indicated. Furthermore, it will be appreciated that some implementations may adopt certain components or features from <FIG> in combination with certain components or features from <FIG> onwards (having regard as appropriate to any inter-dependencies between the various components and features).

<FIG> shows a side view of the internal cartomiser components (analogous to <FIG> after the vent seal has been assembled onto the inner frame). In particular, <FIG> shows a vent seal <NUM> located on top of an airflow tube <NUM> of the inner frame <NUM>. The inner frame <NUM> further comprises a middle section <NUM>, which surrounds part of the atomising chamber, and a base portion <NUM>. The middle section <NUM> includes opposing side walls <NUM>, plus top wall <NUM> (at the bottom of airflow tube <NUM>); together side walls <NUM> and top wall <NUM> define in part the atomising chamber. A wick <NUM> is inserted into the inner frame (from underneath), and passes through the atomising chamber. The cartomiser plug <NUM> is also inserted into the inner frame (again from underneath) to hold the wick in position. The cartomiser plug comprises an upper section <NUM> which completes the atomising chamber (in conjunction with the inner frame <NUM>), and a lower portion <NUM> that provides an end seal for the liquid reservoir <NUM>. Note that the inner frame <NUM> and the cartomiser plug <NUM> are provided with slots (not visible in <FIG>, but analogous to those shown in <FIG>) for receiving and retaining the wick <NUM> in the atomising chamber.

<FIG> shows a top view of the vent seal <NUM>, inner frame <NUM> and wick <NUM> (but without the cartomiser plug <NUM>). In addition to the features mentioned above in respect of <FIG> also shows openings 1671A and 1671B on either side of the lower portion <NUM> of the inner frame. These openings allow the wick <NUM> to pass through the lower portion <NUM> of the inner frame during assembly. Also visible in <FIG>) are two arches 1437A and 1437B, which are formed integrally with the inner frame <NUM> and extend outwards from the side walls <NUM> of the inner frame <NUM>. These arches are positioned at the end of the slots for receiving the wick <NUM>, such that they can be considered as a lateral extension (in the X-dimension) of the roof of these slots. In other words, the inside of each arch forms a continuous surface with the roof of the adjacent slot, shaped to match and accommodate the cylindrical surface of the wick <NUM> as received into the slots. The addition of arches 1437A,B helps to retain the wick <NUM> in the correct location in the atomising chamber, and also helps to reduce liquid leakage from the reservoir <NUM> surrounding the inner frame into the atomising chamber (i.e. so that the only flow from reservoir <NUM> into the atomising chamber is along wick <NUM> itself).

<FIG> present side views of the inner frame <NUM>. More particularly, <FIG> shows the inner frame <NUM> in combination with the vent seal <NUM>, wick <NUM> and cartomiser plug <NUM>, whereas <FIG> shows just the inner frame. It can be seen from <FIG> that the arch <NUM> extending from side wall <NUM> is generally in the shape of an upside-down "U", where the curved portion of the arch is semi-circular in shape for receiving the circular wick <NUM>, and the two short straight walls of each arch descend downwards (away from the mouthpiece end). The inner surface of the arch <NUM> is generally aligned (and continuous) with the roof of adjacent slot <NUM> formed in side wall <NUM>. As shown in <FIG>, these two short straight walls of the arch taper slightly outwards from one another at the bottom (furthest from the curved roof of the arch), and thereby act as a guide to help receive the wick <NUM> into the arch <NUM>. Furthermore, the walls of the arch <NUM> may also extend to, and contact, pedestal <NUM> of the cartomiser plug (see <FIG>). In effect therefore, the wick <NUM> is surrounded by arch <NUM> in combination with pedestal <NUM>, and as noted above, this configuration can help to reduce leakage and retain the wick in position (e. g by resisting rotation of the wick about its main longitudinal axis and/or or displacement of the wick parallel to its main axis).

Returning to <FIG>, the front wall <NUM> (and analogous back wall - not visible in <FIG>) of cartomiser plug <NUM> is slightly different from front wall <NUM> of cartomiser plug <NUM>, such as shown in <FIG>. In particular, front wall <NUM> of cartomiser plug <NUM> comprises three horizontal ribs or ridges. In contrast, the front wall <NUM> of cartomiser plug <NUM> comprises two horizontal ribs or ridges, plus two vertical ribs on either side of the front wall <NUM>. Moreover, the two vertical ribs are joined by a cross ridge (also termed a bump ridge) <NUM> at the top of the front wall <NUM>. There is a similar structure on the back wall of the cartomiser plug <NUM> (not visible in <FIG>).

<FIG> is a cross-section through the cartomiser plug <NUM> (by itself) in a plane normal to the main longitudinal axis of the wick (i.e. the Y-Z plane of <FIG>), passing through the centre of the atomising chamber. This Figure includes dimensions of the cartomiser (in millimetres), but these are given only by way of example, and may vary from one implementation to another. A cartomiser slot <NUM> for receiving wick <NUM> is formed in a side wall <NUM> of the atomising chamber. The wick <NUM> is received into this slot and sits at the end <NUM> of the slot <NUM>. Note that slot <NUM> is generally similar to slot <NUM> (such as described in relation to <FIG>).

Also visible in <FIG> is the bump ridge <NUM>, located along the top of each side wall <NUM>. The bump ridge <NUM> helps to give additional strength and stability to this top portion of the cartomiser plug when assembled with the inner frame <NUM>. For example, the bump ridge can help to improve the seal between the top of the cartomiser plug <NUM> and the inner frame <NUM> to further reduce leakage from the liquid reservoir <NUM> into the atomising chamber.

<FIG> shows two views of the vent seal <NUM> by itself, the drawing to the left is a front (or back) view, while the drawing to the right is a side view. Compared with the vent seal <NUM> shown in <FIG> (for example), it can be seen that vent seal <NUM> is slightly longer (in the main axial direction of the device, i.e. parallel to the Y axis). In addition, the cross-section of the vent seal <NUM> is oval in shape (rather than circular) and the vent seal tapers inwards towards the mouthpiece. This oval shape is also apparent from the top view of <FIG>.

<FIG> and <FIG> show that the airflow tube <NUM> of the inner frame <NUM> has a corresponding shape to the vent seal <NUM>, in that it is again oval in cross-section (in the X-Z plane, perpendicular to the main airflow direction), and tapers towards the mouthpiece <NUM> of the device. It will be appreciated that this correspondence in shape between the vent <NUM> and the inner frame <NUM> allows the vent seal <NUM> to fit onto the inner frame <NUM>. Note also that the airflow tube <NUM> of the inner frame <NUM> shown in <FIG> and <FIG> is slightly shorter than the airflow tube <NUM> of the inner frame <NUM> shown in <FIG>. This reduced height of the airflow tube <NUM> (compared with airflow tube <NUM>) compensates for the increased height of the vent seal <NUM> (compared with vent seal <NUM>), such that the overall height of the cartomiser <NUM> is substantially unchanged.

<FIG> is a top view of the mouthpiece <NUM>, which comprises two primary curved faces <NUM> (analogous to curved faces <NUM> of mouthpiece <NUM> shown in <FIG>). The mouthpiece <NUM> differs from mouthpiece <NUM> in having slight indentations or holes <NUM> on either side of the mouthpiece. These indentations represent a form of texturing, and can be used to hold the mouthpiece more easily, as well as reducing the thickness of the mouthpiece <NUM> in this region (which can assist with moulding). In addition, the mouthpiece <NUM> includes an airflow exit hole <NUM> within a valley region <NUM>. However, compared to the hole <NUM> in valley region <NUM> of mouthpiece <NUM>, which is circular, hole <NUM> is elongated in the width direction (X-axis) of the mouthpiece <NUM>, and hence has an oval or elliptical shape. This increase in size of the mouthpiece hole <NUM> allows the vent seal <NUM> to be visible through the mouthpiece hole <NUM>.

Claim 1:
A cartomiser (<NUM>) for a vapour provision system, the cartomiser including
a container for holding a reservoir (<NUM>) of free liquid to be vaporised;
an atomising chamber (<NUM>);
a porous wick (<NUM>) extending from inside the container, through an aperture in a wall of the atomising chamber, to inside the atomising chamber in order to convey the liquid from the reservoir to the inside of the atomising chamber for vaporisation;
and a resilient seal provided in said aperture to restrict the liquid from entering the atomising chamber from the reservoir except by travelling along the wick;
wherein said resilient seal is provided as a lip seal (<NUM>) comprising a resilient ridge formed on the inside of the aperture and protruding at least partly into the aperture, wherein the lip seal is compressed and/or deflected when the wick is located in the aperture; and
wherein the resilience of the seal is such as to restrict liquid from entering the atomising chamber around the wick without significantly impacting the ability of the wick itself to transfer liquid from the reservoir into the atomising chamber (<NUM>).