Electronic vapour provision device

Technical Field

0001The specification relates to electronic vapour provision devices.

Background

0002Electronic vapour provision devices, such as electronic cigarettes, are typically cigarette-sized and typically function by allowing a user to inhale a nicotine vapour from a liquid store by applying a suction force to a mouthpiece. Some electronic vapour provision devices have an airflow sensor that activates when a user applies the suction force and causes a heater coil to heat up and vaporise the liquid.

0003An electronic cigarette is known from <patcit id="pcit0001" dnum="EP2022349A1"><text>EP 2 022 349 A1</text></patcit>

Summary

0004According to an aspect of the present invention, there is provided an electronic vapour provision device comprising a power cell and a vaporiser, where the vaporiser comprises a heating element and a heating element support, wherein one or more gaps are provided between the heating element and the heating element support; wherein: the heating element is on a support circumferential outer surface of the heating element support; and the one or more gaps are provided between the heating element and the support circumferential outer surface, further wherein the heating element support is a rigid support comprising a porous ceramic material, and the support circumferential outer surface of the heating element support is pitted to form depressions that provide the gaps, further wherein the heating element is a coil wire having a diameter of 0.05 mm to 0.2 mm. The heating element and heating element support may form a heating rod.

0005According to another aspect of the present invention, there is provided a vaporiser, configured for use with the electronic vapour provision device, comprising: a heating element and a heating element support; wherein one or more gaps are provided between the heating element and the heating element support; the heating element is on a support circumferential outer surface of the heating element support; and the one or more gaps are provided between the heating element and the support circumferential outer surface, further wherein the heating element support is a rigid support comprising a porous ceramic material, and the support circumferential outer surface of the heating element support is pitted to form depressions that provide the gaps, further wherein the heating element is a coil wire having a diameter of 0.05 mm to 0.2 mm.

0006The electronic vapour provision device may comprise a liquid store; a wicking element configured to wick liquid from the liquid store to the heating element for vaporising liquid; an air outlet for vaporised liquid produced by the heating element; and the heating element support.

0007The electronic vapour provision device may include a power cell for powering the heating element.

Brief Description of the Drawings

0008For a better understanding of the disclosure, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which: <ul id="ul0001" list-style="none"><li><figref idref="f0001">Figure 1</figref> is a side perspective view of an electronic cigarette;</li><li><figref idref="f0002">Figure 2</figref> is a schematic sectional view of an electronic cigarette having a perpendicular coil;</li><li><figref idref="f0003">Figure 3</figref> is a schematic sectional view of an electronic cigarette having a parallel coil;</li><li><figref idref="f0004">Figure 3A</figref> shows a cross-section through the mouthpiece at the coil.</li><li><figref idref="f0005">Figure 4</figref> is a side perspective view of a heating element coil;</li><li><figref idref="f0005">Figure 5</figref> is a side perspective view of a cylindrical heating element support having a pitted surface;</li><li><figref idref="f0005">Figure 6</figref> is a side perspective view of a heating element coil and heating element support having a pitted surface;</li><li><figref idref="f0006">Figure 7</figref> is a side perspective view of a heating element support having channels;</li><li><figref idref="f0006">Figure 8</figref> is a side perspective view of a heating element coil and heating element support having channels;</li><li><figref idref="f0006">Figure 9</figref> is an end view of the heating element support of <figref idref="f0006">Figure 7</figref>;</li><li><figref idref="f0006">Figure 10</figref> is an end view of the heating element coil and support of <figref idref="f0006">Figure 8</figref>;</li><li><figref idref="f0007">Figure 11</figref> is an end view of a coil and a heating element support having a channel;</li><li><figref idref="f0007">Figure 12</figref> is an end view of a coil and a heating element support having a circular segment cross-section;</li><li><figref idref="f0007">Figure 13</figref> is an end view of a coil and a heating element support having an oval cross-section;</li><li><figref idref="f0007">Figure 14</figref> is an end view of a coil and a heating element support having a flat rectangular cross-section;</li><li><figref idref="f0007">Figure 15</figref> is an end view of a coil and a heating element support having a 4 arm cross, cross-section;</li><li><figref idref="f0007">Figure 16</figref> is an end view of a coil and a heating element support having an 8 arm cross, cross-section;</li><li><figref idref="f0008">Figure 17</figref> is an end view of a coil and a heating element support having an octagonal cross-section;</li><li><figref idref="f0008">Figure 18</figref> is an end view of a coil and a heating element support having a triangular cross-section;</li><li><figref idref="f0008">Figure 19</figref> is an end view of a coil and a heating element support having a square cross-section;</li><li><figref idref="f0008">Figure 20</figref> is an end view of a coil and a heating element support having a hexagonal cross-section;</li><li><figref idref="f0008">Figure 21</figref> is an end view of a coil and a heating element support having a pentagonal cross-section;</li><li><figref idref="f0008">Figure 22</figref> is an end view of a coil and a heating element support having cross-sectional shape of three circles joined together;</li><li><figref idref="f0009 f0010">Figure 23</figref> is a front view of a heating element support substrate and heating element; and</li><li><figref idref="f0009 f0010">Figure 24</figref> is a front view of a heating element support substrate and with a threaded heating element.</li></ul>

Detailed Description

0009In an embodiment there is provided an electronic vapour provision device comprising a power cell and a vaporiser, where the vaporiser comprises a heating element and a heating element support, wherein a gap is provided between the heating element and the heating element support.

0010Having a separate heating element and support allows a finer heating element to be constructed. This is advantageous because a finer heating element can be more efficiently heated. Providing a gap between the heating element and the heating element support allows liquid to be gathered and stored in the gap region for vaporisation. The gap can also act to wick liquid onto the heating element. Also, providing a gap between the heating element and support means that a greater surface area of the heating element is exposed thereby giving a greater surface area for heating and vaporisation.

0011The heating element support comprises a support outer surface and the gap is provided between the heating element and the support outer surface.

0012The heating element and heating element support may form a heating rod. The heating element support is a rigid support. The heating element support may be solid. This has the advantage that a rigid or solid support enables a more fragile, more efficient heating element to be used. The combination of the support and the heating element provides a more robust heating rod.

0013The heating element support is porous. The heating element support comprises a porous ceramic material. Having a porous support enables liquid to be stored in the porous support. Thus the liquid can be easily transferred to the heating element in contact with the support for vaporisation by the heating element. Also, the gap between the heating element and the support allows for wicking of liquid both from the porous support onto the heating element and into the porous support for storage.

0014The heating element can be formed around the heating element support. The heating element is a heating coil. Moreover, the heating coil may be coiled around the heating element support. The heating coil is a wire coil. The gap may be between a coil turn and the heating element support. Gaps may be between coil turns and the heating element support.

0015Having a heating element that wraps around the support provides a more sturdy construction. The support also facilitates the creation of a coil by enabling wire to be wrapped around the support. By providing a gap between a coil turn and the support, liquid can be wicked into the gap and held in the gap for vaporisation. In particular, liquid can be wicked by the spaces between coil turns and into the gap between a coil turn and the support.

0016The vaporiser can further comprise a vaporisation cavity configured such that in use the vaporisation cavity is a negative pressure region. At least part of the heating element may be inside the vaporisation cavity. Furthermore, the electronic vapour provision device can comprise a mouthpiece section and the vaporiser can be part of the mouthpiece section.

0017By having the heating element in the vaporisation cavity, which in turn is a negative pressure region when a user inhales through the electronic vapour provision device, the liquid is directly vaporised and inhaled by the user.

0018The heating element support may be elongated in a lengthwise direction. Furthermore, the heating element support may have a side channel running lengthwise along the support. Alternatively or additionally, the heating element support may comprise two or more side channels running lengthwise along the support. Moreover, the side channels may be distributed substantially evenly around the heating element support.

0019A channel in the support provides a natural gap between the support and the heating element. This is particularly the case when the heating element is a coil wound around the support. The channel therefore provides the necessary gap to wick and store liquid. The area of the heating element exposed is also increased along the channel leading to increased vaporisation in this region.

0020The heating element support may be non-cylindrical. The heating element support may be cylinder-like but non-cylindrical. The heating element support may have a non-circular cross-section. The heating element support has a pitted surface.

0021Since a coil is naturally cylindrical when formed due to the rigidity of the wire, a non-cylindrical support has the advantage that there will naturally be gaps between the coil and the support. These gaps lead to increased wicking, liquid storage and vaporisation. A cylinder-like support with a pitted surface provides gaps between the support and the coil in the pit regions. Cross-sections are sections perpendicular to the elongated lengthwise direction.

0022The cross-sectional shape of the heating element support can be a polygon. For example, the cross-sectional shape of the heating element support may have 3 sides, 4 sides, 5 sides, 6 sides or 8 sides.

0023Alternatively, the cross-sectional shape of the heating element support can be a flat rectangle. Alternatively, the cross-sectional shape of the heating element support can be an ellipse. Alternatively, the cross-sectional shape of the heating element support can be equivalent to three overlapping circles joined together.

0024Alternatively, the cross-sectional shape of the heating element support can be a cross. The cross-sectional shape of the heating element support may be a cross having 4 arms, or a cross having 8 arms.

0025Again, these various shapes of support provide natural gaps between the support and a heating element coil that is wound around the support. These gaps lead to increased wicking, liquid storage and vaporisation.

0026Alternatively, the heating element support may be a flat planar substrate. Moreover, the heating element can be on one surface of the heating element support. Furthermore, the heating element may be threaded in and out of the heating element support. The heating element may be wrapped around the heating element support. Moreover, the heating element support may comprise a substrate having holes.

0027In another embodiment there is provided an electronic vapour provision device comprising a liquid store; a wicking element configured to wick liquid from the liquid store to a heating element for vaporising liquid; an air outlet for vaporised liquid to pass out of; and a heating element support, wherein a gap is provided between the heating element and the heating element support. The electronic vapour provision device may comprise a power cell for powering the heating element.

0028Referring to <figref idref="f0001">Figure 1</figref> there is shown an embodiment of the electronic vapour provision device 1 in the form of an electronic cigarette 1 comprising a mouthpiece 2 and a body 3. The electronic cigarette 1 is shaped like a conventional cigarette having a cylindrical shape. The mouthpiece 2 has an air outlet 4 and the electronic cigarette 1 is operated when a user places the mouthpiece 2 of the electronic cigarette 1 in their mouth and inhales, drawing air through the air outlet 4. Both the mouthpiece 2 and body 3 are cylindrical and are configured to connect to each other coaxially so as to form the conventional cigarette shape.

0029<figref idref="f0002">Figures 2</figref> shows an example of the electronic cigarette 1 of <figref idref="f0001">Figure 1</figref>. The body 3 comprises two detachable parts, comprising a battery assembly 5 part and a vaporiser 6 part, and the mouthpiece 2 comprises a liquid store 7. The electronic cigarette 1 is shown in its assembled state, wherein the detachable parts 2, 5, 6 are connected in the following order: mouthpiece 2, vaporiser 6, battery assembly 5. Liquid wicks from the liquid store 7 to the vaporiser 6. The battery assembly 5 provides electrical power to the vaporiser 6 via mutual electrical contacts of the battery assembly 5 and the vaporiser 6. The vaporiser 6 vaporises the wicked liquid and the vapour passes out of the air outlet 4. The liquid may for example comprise a nicotine solution.

0030The battery assembly 5 comprises a battery assembly casing 8, a power cell 9, electrical contacts 10 and a control circuit 11.

0031The battery assembly casing 8 comprises a hollow cylinder which is open at a first end 12. For example, the battery assembly casing 8 may be plastic. The electrical contacts 10 are located at the first end 12 of the casing 8, and the power cell 9 and control circuit 11 are located within the hollow of the casing 8. The power cell 9 may for example be a Lithium Cell.

0032The control circuit 11 includes an air pressure sensor 13 and a controller 14 and is powered by the power cell 9. The controller 14 is configured to interface with the air pressure sensor 13 and to control provision of electrical power from the power cell 9 to the vaporiser 6.

0033The vaporiser 6 comprises a vaporiser casing 15, electrical contacts 16, a heating element 17, a wicking element 18, a vaporisation cavity 19 and a heating element support 20.

0034The vaporiser casing 15 comprises a hollow cylinder which is open at both ends with an air inlet 21. For example, the vaporiser casing 15 may be formed of an aluminium alloy. The air inlet 21 comprises a hole in the vaporiser casing 15 at a first end 22 of the vaporiser casing 15. The electrical contacts 16 are located at the first end 22 of the vaporiser casing 15.

0035The first end 22 of the vaporiser casing 15 is releasably connected to the first end 12 of the battery assembly casing 8, such that the electrical contacts 16 of the vaporiser are electrically connected to the electrical contacts 10 of the battery assembly. For example, the device 1 may be configured such that the vaporiser casing 15 connects to the battery assembly casing 8 by a threaded connection.

0036The heating element 17 is formed of a single wire and comprises a heating element coil 23 and two leads 24, as is illustrated in <figref idref="f0005">Figures 4 and 6</figref>. For example, the heating element may be formed of Nichrome. The coil 23 comprises a section of the wire where the wire is formed into a helix about an axis A. At either end of the coil 23, the wire departs from its helical form to provide the leads 24. The leads 24 are connected to the electrical contacts 16 and are thereby configured to route electrical power, provided by the power cell 9, to the coil 23.

0037The wire of the coil 23 is approximately 0.12 mm in diameter. The coil 23 is approximately 25 mm in length, has an internal diameter of approximately 1 mm and a helix pitch of approximately 420 micrometers. The void between the successive turns of the coil is therefore approximately 300 micrometers.

0038The heating element 17 is located towards the second end 25 of the vaporiser casing 15 and is orientated such that the axis A of the coil 23 is perpendicular to the cylindrical axis B of the vaporiser casing 15. The heating element 17 is thus perpendicular to the longitudinal axis C of the electronic cigarette 1. Moreover, the device 1 is configured such that the axis A of the coil is substantially perpendicular to airflow through the device when a user sucks on the device. Use of the device 1 by a user is later described in more detail.

0039The wicking element 18 extends from the vaporiser casing 15 into contact with the liquid store 7 of the mouthpiece 2. The wicking element 18 is configured to wick liquid in the direction W from the liquid store 7 of the mouthpiece 2 to the heating element 17. In more detail, the wick 18 comprises an arc of porous material extending from a first end of the coil 23, out past the second end 25 of the vaporiser casing 15 and back to a second end of the coil. For example, the porous material may be nickel foam, wherein the porosity of the foam is such that the described wicking occurs.

0040The vaporisation cavity 19 comprises a region within the hollow of the vaporiser casing 15 in which liquid is vaporised. The heating element 17, heating element support 20 and portions 26 of the wicking element 18 are situated within the vaporisation cavity 19.

0041The heating element support 20 is configured to support the heating element 17 and to facilitate vaporisation of liquid by the heating element 17. The heating element support 20 is an inner support and is illustrated in <figref idref="f0005">Figures 5 and 6</figref>. The support 20 comprises a rigid cylinder of ceramic material. The support 20 is situated coaxially within the helix of the heating element coil 23 and is slightly longer than the coil 23, such that the ends of the support 20 protrude from the ends of the coil 23. The diameter of the cylindrical support 20 is similar to the inner diameter of the helix. As a result, the wire of the coil 23 is substantially in contact with the support 20 and is thereby supported, facilitating maintenance of the shape of the coil 23. The heating element coil 23 is thus coiled, or wrapped, around the heating element support 20. The combination of the support 20 and the coil 23 of the heating element 17 provides a heating rod 27, as illustrated in <figref idref="f0005">Figures 5 and 6</figref>. The heating rod is later described in more detail with reference to <figref idref="f0005">Figures 5 and 6</figref>.

0042The surface 28 of the support 20 provides a route for liquid from the wick element 18 to wick onto and along, improving the provision of liquid to the vicinity of the heating element 17 for vaporisation. The surface 28 of the support 20 also provides surface area for exposing wicked liquid to the heat of the heating element 17.

0043The mouthpiece 2 comprises a mouthpiece casing 29. The mouthpiece casing 29 comprises a hollow cylinder which is open at a first end 30, with the air outlet 4 comprising a hole in the second end 31 of the casing. For example, the mouthpiece casing may be formed of plastic.

0044The liquid store 7 is situated within the hollow of the mouthpiece casing 29. For example, the liquid store may comprise foam, wherein the foam is substantially saturated in the liquid intended for vaporisation. The cross-sectional area of the liquid store 7 is less than that of the hollow of the mouthpiece casing so as to form an air passageway 32 between the first end 30 of the mouthpiece casing 29 and the air outlet 4.

0045The first end 30 of the mouthpiece casing 29 is releasably connected to the second end 25 of the vaporiser casing 15, such that the liquid store 7 is in contact with a portion 33 of the wicking element 18 which protrudes from the vaporiser 6.

0046Liquid from the liquid store 7 is absorbed by the wicking element 18 and wicks along route W throughout the wicking element 18. Liquid then wicks from the wicking element 18 onto and along the coil 23 of the heating element 17, and onto and along the support 20.

0047There exists a continuous inner cavity 34 within the electronic cigarette 1 formed by the adjacent hollow interiors' of the mouthpiece casing 29, the vaporiser casing 15 and the battery assembly casing 8.

0048In use, a user sucks on the second end 31 of the mouthpiece 2. This causes a drop in the air pressure throughout the inner cavity 34 of the electronic cigarette 1, particularly at the air outlet 4.

0049The pressure drop within the inner cavity 34 is detected by the pressure sensor 13. In response to detection of the pressure drop by the pressure sensor, the controller 14 triggers the provision of power from the power cell 9 to the heating element 17 via the electrical contacts 10, 16. The coil of the heating element 17 therefore heats up. Once the coil 17 heats up, liquid in the vaporisation cavity 19 is vaporised. In more detail, liquid on the heating element 17 is vaporised, liquid on the heating element support 20 is vaporised and liquid in portions 26 of the wicking element 18 which are in the immediate vicinity of the heating element 17 may be vaporised.

0050The pressure drop within the inner cavity 34 also causes air from outside of the electronic cigarette 1 to be drawn, along route F, through the inner cavity from the air inlet 21 to the air outlet 4. As air is drawn along route F, it passes through the vaporisation cavity 19 and the air passageway 32. The vaporised liquid is therefore conveyed by the air movement along the air passageway 32 and out of the air outlet 4 to be inhaled by the user.

0051As the air containing the vaporised liquid is conveyed to the air outlet 4, some of the vapour may condense, producing a fine suspension of liquid droplets in the airflow. Moreover, movement of air through the vaporiser 6 as the user sucks on the mouthpiece 2 can lift fine droplets of liquid off of the wicking element 18, the heating element 17 and/or the heating element support 20. The air passing out of the outlet may therefore comprise an aerosol of fine liquid droplets as well as vaporised liquid.

0052The pressure drop within the vaporisation cavity 19 also encourages further wicking of liquid from the liquid store 7, along the wicking element 18, to the vaporisation cavity 19.

0053<figref idref="f0003">Figure 3</figref> shows a further example of the electronic cigarette 1 of <figref idref="f0001">Figure 1</figref>. The body 3 is a single part, referred to herein as a battery assembly 50, and the mouthpiece 2 comprises a liquid store 51 and a vaporiser 52. The electronic cigarette 1 is shown in its assembled state, wherein the detachable parts 2, 50 are connected. Liquid wicks from the liquid store 51 to the vaporiser 52. The battery assembly 50 provides electrical power to the vaporiser 52 via mutual electrical contacts of the battery assembly 50 and the mouthpiece 2. The vaporiser 52 vaporises the wicked liquid and the vapour passes out of the air outlet 4. The liquid may for example comprise a nicotine solution.

0054The battery assembly 50 comprises a battery assembly casing 53, a power cell 54, electrical contacts 55 and a control circuit 56.

0055The battery assembly casing 53 comprises a hollow cylinder which is open at a first end 57. For example, the battery assembly casing may be plastic. The electrical contacts 55 are located at the first end 57 of the casing 53, and the power cell 54 and control circuit 56 are located within the hollow of the casing 53. The power cell 54 may for example be a Lithium Cell.

0056The control circuit 56 includes an air pressure sensor 58 and a controller 49 and is powered by the power cell 54. The controller 49 is configured to interface with the air pressure sensor 58 and to control provision of electrical power from the power cell 54 to the vaporiser 52, via the electrical contacts 55.

0057The mouthpiece 2 further comprises a mouthpiece casing 59 and electrical contacts 60. The mouthpiece casing 59 comprises a hollow cylinder which is open at a first end 61, with the air outlet 4 comprising a hole in the second end 62 of the casing 59. The mouthpiece casing 59 also comprises an air inlet 63, comprising a hole near the first end 61 of the casing 59. For example, the mouthpiece casing may be formed of aluminium.

0058The electrical contacts 60 are located at the first end of the casing 59. Moreover, the first end 61 of the mouthpiece casing 59 is releasably connected to the first end 57 of the battery assembly casing 53, such that the electrical contacts 60 of the mouthpiece are electrically connected to the electrical contacts 55 of the battery assembly. For example, the device 1 may be configured such that the mouthpiece casing 59 connects to the battery assembly casing 53 by a threaded connection.

0059The liquid store 51 is situated within the hollow mouthpiece casing 59 towards the second end 62 of the casing 59. The liquid store 51 comprises a cylindrical tube of porous material saturated in liquid. The outer circumference of the liquid store 51 matches the inner circumference of the mouthpiece casing 59. The hollow of the liquid store 51 provides an air passageway 64. For example, the porous material of the liquid store 51 may comprise foam, wherein the foam is substantially saturated in the liquid intended for vaporisation.

0060The vaporiser 52 comprises a heating element 17, a wicking element 65, a heating element support 20 and a vaporisation cavity 66.

0061The wicking element 65 comprises a cylindrical tube of porous material and is situated within the mouthpiece casing 59, towards the first end 61 of the casing 59, such that it abuts the liquid store 51. The outer circumference of the wicking element 65 matches the inner circumference of the mouthpiece casing 59. The wicking element 65 is configured to wick liquid in the direction W from the liquid store 51 of the mouthpiece 2 to the heating element 17. For example, the porous material of the wicking element 65 may be nickel foam, wherein the porosity of the foam is such that the described wicking occurs. Once liquid wicks W from the liquid store 6 to the wicking element 65, it can be stored in the porous material of the wicking element 65. Thus, the wicking element 65 is an extension of the liquid store 51.

0062The heating element 17 is formed of a single wire and comprises a heating element coil 23 and two leads 24, as is illustrated in <figref idref="f0005">Figures 4 and 6</figref>. For example, the heating element may be formed of Nichrome. The coil 23 comprises a section of the wire where the wire is formed into a helix about an axis A. At either end of the coil 23, the wire departs from its helical form to provide the leads 24. The leads 24 are connected to the electrical contacts 60 and are thereby configured to route electrical power, provided by the power cell 54, to the coil 23.

0063The wire of the coil 23 is approximately 0.12 mm in diameter. The coil 23 is approximately 25 mm in length, has an internal diameter of approximately 1 mm and a helix pitch of approximately 420 micrometers. The void between the successive turns of the coil is therefore approximately 300 micrometers

0064The heating element 17 is located inside the tube of the wicking element 65 and is orientated such that the axis of the coil 23 is aligned with the cylindrical axis B of the mouthpiece casing 59. The axis A of the heating element coil 23 is thus parallel to the longitudinal axis C of the electronic cigarette 1. Moreover, the device 1 is configured such that the axis A of the coil 23 is substantially parallel to airflow F through the device when a user sucks on the device. Use of the device 1 by a user is later described in more detail.

0065<figref idref="f0004">Figure 3a</figref> shows a cross-section through the mouthpiece 2 at the coil 23. As is illustrated in <figref idref="f0004">Figure 3a</figref>, the cross-sectional profile of the wicking element 65 is configured such that parts 65a of the inner surface 65b of the wicking element 65 are in contact with the coil 23. This provides a route for liquid to wick from the wicking element 65 to the coil 23.

0066The vaporisation cavity 66 comprises a region within the hollow of the mouthpiece casing 59 in which liquid is vaporised. The heating element 17, heating element support 20 and a portion 67 of the wicking element 65 are situated within the vaporisation cavity 66.

0067The heating element support 20 is configured to support the heating element 17 and to facilitate vaporisation of liquid by the heating element 17. The heating element support is an inner support and is illustrated in <figref idref="f0005">Figures 5 and 6</figref>. The support 20 comprises a rigid cylinder of ceramic material. The support 20 is situated coaxially within the helix of the heating element coil 23 and is slightly longer than the coil 23, such that the ends of the support 20 protrude from the ends of the coil 23. The diameter of the cylindrical support 20 is similar to the inner diameter of the helix. As a result, the wire of the coil 23 is substantially in contact with the support 20 and is thereby supported, facilitating maintenance of the shape of the coil 23. The heating element coil 23 is thus coiled, or wrapped, around the heating element support 20. The combination of the support 20 and the coil 23 of the heating element 17 provides a heating rod 27, as illustrated in <figref idref="f0005">Figures 5 and 6</figref>. The heating rod 27 is later described in more detail with reference to <figref idref="f0005">Figures 5 and 6</figref>.

0068The surface 28 of the support 20 provides a surface for liquid from the wicking element 65 to wick onto and along, improving the provision of liquid to the vicinity of the heating element 17 for vaporisation. The surface 28 of the support 20 also provides surface area for exposing wicked liquid to the heat of the heating element 17.

0069There exists a continuous inner cavity 68 within the electronic cigarette 1 formed by the adjacent hollow interiors' of the mouthpiece casing 59 and the battery assembly casing 53.

0070In use, a user sucks on the second end 62 of the mouthpiece casing 59. This causes a drop in the air pressure throughout the inner cavity 68 of the electronic cigarette 1, particularly at the air outlet 4.

0071The pressure drop within the inner cavity 68 is detected by the pressure sensor 58. In response to detection of the pressure drop by the pressure sensor 58, the controller 49 triggers the provision of power from the power cell 54 to the heating element 17 via the electrical contacts 55, 60. The coil of the heating element 17 therefore heats up. Once the coil 17 heats up, liquid in the vaporisation cavity 66 is vaporised. In more detail, liquid on the heating element 17 is vaporised, liquid on the heating element support 20 is vaporised and liquid in the portions 67 of the wicking element 65 which are in the immediate vicinity of the heating element 17 may be vaporised.

0072The pressure drop within the inner cavity 68 also causes air from outside of the electronic cigarette 1 to be drawn, along route F, through the inner cavity from the air inlet 63 to the air outlet 4. As air is drawn along route F, it passes through the vaporisation cavity 66, picking up vaporised liquid, and the air passageway 64. The vaporised liquid is therefore conveyed along the air passageway 64 and out of the air outlet 4 to be inhaled by the user.

0073As the air containing the vaporised liquid is conveyed to the air outlet 4, some of the vapour may condense, producing a fine suspension of liquid droplets in the airflow. Moreover, movement of air through the vaporiser 52 as the user sucks on the mouthpiece 2 can lift fine droplets of liquid off of the wicking element 65, the heating element 17 and/or the heating element support 20. The air passing out of the air outlet may therefore comprise an aerosol of fine liquid droplets as well as vaporised liquid.

0074With reference to <figref idref="f0005">Figures 5 and 6</figref>, the circumferential outer surface 28 of the heating element support 20 is pitted, such that a plurality of depressions 70, or recesses, exist in the surface 28. When considering the presence of the plurality of depressions 70, the support 20 is substantially cylindrical.

0075Gaps 80 are formed between the heating element support 20 and the coil 23 where the coil 23 overlaps depressions 70 in the surface 28. In more detail, where the wire of the coil 23 passes over a depression 70 in the surface 28, a gap 80 is provided between the wire and the area of the surface 28 immediately under the wire due to the wire substantially maintaining its helical form. The gaps 80 are therefore disposed in a radial direction from the axis A of the coil, between the surface 28 of the support 20 and the wire of the coil 23. The distance between the wire and the surface 28 at each gap 80 is in the range of 10 micrometers to 500 micrometers. The gaps 80 are configured to facilitate the wicking of liquid onto and along the length of the support 20 through capillary action at the gaps 80.

0076The depressions 70 in the circumferential surface 28 and/or the gaps 80 provide areas in which liquid can gather on the surface 28 of the support 20 prior to vaporisation, and thereby provide areas for liquid to be stored prior to vaporisation. The depressions 70 also increase the surface area of the support 20, thus increasing the additional surface area for exposing liquid to the coil 23 for vaporisation provided by the support 20. The depressions 70 also expose more of the coil 23 for increased vaporisation in these areas.

0077Many alternatives and variations to the embodiments described above are possible. For example, <figref idref="f0006 f0007 f0008 f0009 f0010">Figures 7 to 24</figref> show different configurations of heating element 17 and heating element support 20. In each case, a gap 80 or gaps 80 are provided between the outer surface 28 of the support 20 and the wire of the coil 23. These gaps 80 provide the advantages already described. <figref idref="f0006 f0007 f0008">Figures 7 to 22</figref> illustrate how gaps 80 can be provided by one or more inward deviations 81 in the cross-sectional profile of a support 20, where that profile otherwise follows the cross-sectional inner profile of a coil 23.

0078<figref idref="f0006">Figures 7 to 10</figref> show a different example of a heating element support 20. <figref idref="f0006">Figures 7 and 9</figref> illustrate different views of the heating element support 20 alone. <figref idref="f0006">Figures 8 and 10</figref> illustrate different views of the heating rod 29, comprising the coil 23 wrapped around the support 20. Here, the heating element support 20 is substantially cylindrical in shape and has channels 82, or longitudinal grooves 82, in the outer surface 28 of the support 20 running along its length. Each channel 82 is a depression 70, 81 in the surface of the heating element support 20 running along the length of the support 20. Four channels 82 are spaced evenly around the circumference of the heating element support 20.

0079As shown in <figref idref="f0006">Figure 8 and Figure 10</figref>, when the coil 23 is wound around the heating element support 20, gaps 80 are provided between the surface 28 of the support 20 at the channels 82 and the wire of the coil 23 sections overlapping the channels 82.

0080<figref idref="f0007 f0008">Figures 11 to 22</figref> each show an example of an elongated heating element support 20 with a coil 23 wound around it and a gap 80 or gaps 80 provided between the coil 23 and the heating element support 20 by virtue of the cross-sectional shape of the support 20. Each example has a different cross-sectional shape as will be described. Cross-sections are sections perpendicular to the elongated lengthwise direction of the support 20.

0081In the example shown in <figref idref="f0007">Figure 11</figref>, the heating element support 20 is substantially cylindrical with a depression 70 comprising a single channel 82 running along its length. Thus the cross-sectional shape of the heating element support 20 is a circle with a small indent 81 for the channel 82. Gaps 80 are provided where the coil 23 overlaps the channel 82.

0082In the example shown in <figref idref="f0007">Figure 12</figref>, the heating element support 20 has a cross-sectional shape being a major segment of a circle. This corresponds to an otherwise cylindrical shape with a longitudinal depression 70, 81, and results in a flat face running along the length of the heating element support 20. The coil 23 is wound around the heating element support 20 but the rigidity of the coil 23 wire prevents the coil 23 from following the shape of the heating element support 20 in the flat region. Thus a gap 80 is provided between the heating element support 20 and the coil 23 in the area of the flat region.

0083In the example shown in <figref idref="f0007">Figure 13</figref>, the heating element support 20 has a cross-sectional shape being an ellipse. The coil 23 is wound around the heating element support 20 but the rigidity of the coil 23 wire causes the coil 23 to form a more rounded shape than the ellipse, thereby providing gaps 80 between the heating element support 20 and the coil 23.

0084In the example shown in <figref idref="f0007">Figure 14</figref>, the heating element support 20 is a flat bar having a cross-sectional shape being a flat rectangle. The coil 23 is wound around the heating element support 20 but the rigidity of the coil 23 wire causes the coil 23 to form a more rounded shape than the rectangle, thereby providing gaps 80 between the heating element support 20 and the coil 23.

0085In the example shown in <figref idref="f0007">Figure 15</figref>, the heating element support 20 has a cross-sectional shape being a 4-arm cross, where the arms are spaced evenly apart. The coil 23 is wound around the heating element support 20 and gaps 80 are provided between adjacent arm sections and the coil 23.

0086In the example shown in <figref idref="f0007">Figure 16</figref>, the heating element support 20 has a cross-sectional shape being an 8-arm cross, where the arms are spaced evenly apart. The coil 23 is wound around the heating element support 20 and gaps 80 are provided between adjacent arm sections and the coil 23. <figref idref="f0008">Figures 17 to 21</figref> show examples where the heating element support 20 has a cross-sectional shape being a regular polygon. Each of these has a different number of sides <figref idref="f0008">Figure 17</figref> is an octagon, <figref idref="f0008">Figure 18</figref> is a triangle, <figref idref="f0008">Figure 19</figref> is a square, <figref idref="f0008">Figure 20</figref> is a hexagon and <figref idref="f0008">Figure 21</figref> is a pentagon. The coil 23 is wound around the heating element support 20 and is in contact with the heating element support 20 at the edges of the support 20 corresponding to the corners of the cross-sectional shapes. In this way, polygons with more sides have more contact with the coil 23 and provide a greater number of smaller gaps 80 between the coil 23 and the heating element support 20. This enables a cross-sectional shape to be selected that gives an optimum amount of contact between the heating element support 20 and the coil 23, and optimum gap 80 formation.

0087In the example shown in <figref idref="f0008">Figure 22</figref>, the heating element support 20 has a cross-sectional shape corresponding to three overlapping circles joined together. The coil 23 is wound around the heating element support 20 and gaps 80 are provided between adjacent circle sections and the coil 23.

0088The distance between the wire and the surface 28 at each gap 80 is described above as being in the range of 10 micrometers to 500 micrometers. However, other gap 80 sizes are possible.

0089The wire of the coil 23 is described above as being approximately 0.12 mm thick. However, other wire diameters are possible. The diameter of the coil 23 wire is in the range of 0.05 mm to 0.2 mm. Moreover, the coil 23 length may be different to that described above. For example, the coil 23 length may be in the range of 20 mm to 40 mm.

0090The internal diameter of the coil 23 may be different to that described above. For example, the internal diameter of the coil 23 may be in the range of 0.5 mm to 2 mm.

0091The pitch of the helical coil 23 may be different to that described above. For example, the pitch may be between 120 micrometers and 600 micrometers.

0092Furthermore, although the distance of the voids between turns of the coil is described above as being approximately 300, different void distances are possible. For example, the void may be between 20 micrometers and 500 micrometers.

0093The size of the gaps 80 may be different to that described above.

0094Where channels 82 are provided in the heating element support 20, a number other than one or four can be used.

0095Channels 82 have been described as longitudinal grooves along the surface 28 of cylindrical supports 20. However, the channels 82 may, for example, alternatively or additionally comprise helical grooves in the surface 28 of a cylindrical support 20, spiralling about the axis of the support. Alternatively or additionally the channels 82 may comprise circumferential rings around the surface 28 of the support 20.

0096In embodiments, the support 20 is described as being slightly longer than the coil 23, such that it protrudes from either end of the coil 23. Alternatively, the support 20 may be shorter in length than the coil 23 and may therefore reside entirely within the bounds of the coil.

0097The heating element 17 is not restricted to being a coil 23, and may be another wire form such as a zig-zag shape.

0098Heating rods 29 are described above comprising an elongated heating element support 20 with a coil 23 wound around it and a gap 80 or gaps 80 provided between the coil 23 and the heating element support 20 by virtue of the cross-sectional shape of the support 20 comprising a polygon. In this case, the cross-sectional shape of the heating element support 20 may for example be a 3 sided, 4 sided, 5 sided, 6 sided or an 8 sided polygon.

0099The heating element support 20 may be cylinder-like but non-cylindrical.

0100<figref idref="f0009 f0010">Figures 23 and 24</figref> show examples of a further type of heating element support 20. Again, in each case the shape of support 20 provides natural gaps 80 between the support 20 and a heating element 17. These gaps 80 facilitate increased wicking, liquid storage and vaporisation.

0101In <figref idref="f0009 f0010">Figure 23</figref>, a heating element support 20 and heating element 17 is shown. The heating element support 20 is a substantially flat substrate and the heating element 17 is arranged on the surface of the substrate in a zig-zag configuration to maximize the length of the heating element 17 for a given surface area of substrate. The heating element support 20 has substrate apertures 83, and gaps 80 are formed between the heating element support 20 and the heating element 17 when the heating element 17 overlaps the substrate apertures 83.

0102<figref idref="f0009 f0010">Figure 24</figref> shows an example similar to that shown in <figref idref="f0009 f0010">Figure 23</figref>. A heating element support 20 is a flat substrate comprising substrate apertures 83 and a zig-zag heating element 17. In this example, the substrate apertures 83 are located at the turning points of the zig-zag heating element 17 and the heating element 17 wire is threaded in and out of the substrate apertures 83 on respective turns such that the heating element 17 lies of both surfaces of the flat substrate. Gaps 80 are provided between the heating element 17 and the substrate at the substrate aperture 83 locations.

0103The heating element support 20 comprises a porous material which is a porous ceramic to allow liquid storage within the support 20.

0104An electronic vapour provision device comprising an electronic cigarette 1 is described herein. However, other types of electronic vapour provision device are possible.

0105The electronic cigarette 1 is not restricted to the sequence of components described and other sequences could be used such as the control circuit 11, 56 being in the tip of the device or the liquid store 7,51 being in the electronic cigarette 1 body 3 rather than the mouthpiece 2.

0106The vaporiser 6, 52 may form part of the electronic cigarette 1 body 3.

0107Where the heating element support 20 is a substrate, the heating element 17 could be wrapped around the substrate. Furthermore, the heating element 17 may be threaded in and out of the heating element support 20.

0108An air pressure sensor 13, 58 is described herein. In embodiments, an airflow sensor may alternatively or additionally be used to detect that a user is sucking on the device 1.

0109Reference herein to a vaporisation cavity 19, 66 may be replaced by reference to a vaporisation region.

0110The electronic cigarette 1 of <figref idref="f0002">Figure 2</figref> is described as comprising three detachable parts, the mouthpiece 2, the vaporiser 6 and the battery assembly 5. Alternatively, the electronic cigarette 1 may be configured such these parts 2, 6, 5 are combined into a single integrated unit. In other words, the mouthpiece 2, the vaporiser 6 and the battery assembly 5 may not be detachable. As a further alternative, the mouthpiece 2 and the vaporiser 6 may comprise a single integrated unit, or the vaporiser 6 and the battery assembly 5 may comprise a single integrated unit.

0111The electronic cigarette 1 of <figref idref="f0003">Figure 3</figref> is described as comprising two detachable parts, the mouthpiece 2 and the body comprising the battery assembly 50. Alternatively, the electronic cigarette 1 may be configured such these parts 2, 50 are combined into a single integrated unit. In other words, the mouthpiece 2 and the body 3 may not be detachable.

0112Although examples have been shown and described it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention.

0113In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced and provide for superior electronic vapour provision. 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 teach the claimed features. 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, and that other embodiments may be utilised and modifications may be made without departing from the scope of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. Any feature of any embodiment can be used independently of, or in combination with, any other feature.