WO2021099491A1

WO2021099491A1 - Electronic cigarette

Info

Publication number: WO2021099491A1
Application number: PCT/EP2020/082732
Authority: WO
Inventors: Kyle ADAIR; Andrew Robert John ROGAN; Glenn Harrison; Eduardo Jose GARCIA GARCIA
Original assignee: Jt International Sa
Priority date: 2019-11-21
Filing date: 2020-11-19
Publication date: 2021-05-27
Also published as: TW202121999A

Abstract

An electronic cigarette (1) comprises a vaporizing unit (16) and a liquid store (18). The vaporizing unit (16) comprises a plurality of fluidic channels (20) configured to receive liquid from the liquid store (18) and a surface (20a) of the fluidic channels (20) is configured to be heated to vaporize liquid in the fluidic channels (20). The fluidic channels (20) are separated into a plurality of groups (G1 to Gi), each group (G1 to Gi) of fluidic channels (20) is thermally connected to a separate heating element (19), and the groups (G1 to Gi) of fluidic channels (20) have different cross-sectional areas.

Description

ELECTRONIC CIGARETTE

Technical Field

The present disclosure relates to electronic cigarettes, and in particular to a vaporizing unit for an electronic cigarette.

Technical Background

The term electronic cigarette, or e-cigarette, is usually applied to a handheld electronic device that simulates the feeling or experience of smoking tobacco in a traditional cigarette. Common e-cigarettes work by heating an aerosol-generating liquid to generate a vapor that cools and condenses to form an aerosol which is then inhaled by the user.

Accordingly, using e-cigarettes is also sometimes referred to as “vaping”. The aerosol-generating liquid in the electronic cigarette usually comprises nicotine, propylene glycol, glycerin and flavorings.

Typical electronic cigarette vaporizers, i.e. systems or sub-systems for vaporizing the liquid, utilize a cotton wick and heating element to produce vapor from liquid stored in a capsule or tank. When a user operates the e-cigarette, liquid that has soaked into the wick is heated by the heating element, producing a vapor which cools and condenses to form an aerosol which may then be inhaled. To facilitate the ease of use of e-cigarettes, cartridges are often used. These cartridges are configured as “cartomizers”, which means an integrated component formed from a liquid store, a fluid transfer element (a wick), a heater and electrical connectors to establish a connection between the heating element and the power supply unit. The complexity of these traditional cartridges is often associated with drawbacks, such as inconsistent vapor generation (and, hence, inconsistent aerosol delivery to the user) and inconsistent performance over time.

In view of the above, the present disclosure seeks to provide an electronic cigarette with a high controllability in terms of vapor generation and consistent performance over time. Embodiments of the present disclosure seek in particular to provide an electronic cigarette which can provide a variable and optimized heating temperature to improve the vaporization of different liquids and/or which can provide control over the volume of vapor that is generated and/or in which automatic cleaning of a vaporizing unit is facilitated.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided an electronic cigarette comprising a main body portion, a vaporizing unit and a liquid store, wherein: the vaporizing unit comprises a plurality of fluidic channels configured to receive liquid from the liquid store, a surface of the fluidic channels is configured to be heated to vaporize liquid in the fluidic channels, the fluidic channels are separated into a plurality of groups, each group of fluidic channels is thermally connected to a separate heating element, and the groups of fluidic channels have different cross-sectional areas.

The electronic cigarette provides a high degree of controllability in terms of vapor delivery and consistent performance over time. In particular, by separating the fluidic channels into a plurality of groups and by thermally connecting each group of fluidic channels to a separate heating element, it is possible to provide a variable and optimized heating temperature to improve the vaporization of different liquids. In addition, by providing groups of channels with different cross-sectional areas, the volume of vapor that is generated can be controlled.

As used herein, the term “electronic cigarette” may include an electronic cigarette configured to deliver an aerosol to a user, including an aerosol for smoking. An aerosol for smoking may refer to an aerosol with particle sizes of 0.5 to 10 pm. The particle size may be less than 10 or 7 pm. The electronic cigarette may be portable.

In general terms, a vapor is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapor can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapor’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

The cross-sectional area of the fluidic channels may be the same within each group of fluidic channels. Such an arrangement may provide consistent vapor generation and/or may facilitate manufacture of the vaporizing unit.

The length of the fluidic channels in one group may be different from the length of the fluidic channels in another group. Such an arrangement may provide even greater control over the volume of vapor that is generated.

The electronic cigarette may further comprise a controller configured to selectively operate one or more of the separate heating elements to selectively heat one or more of the corresponding groups of fluidic channels. With this arrangement, just one of the groups of fluidic channels can be heated or several of the groups of fluidic channels can be heated simultaneously, providing enhanced control over vapor generation.

The electronic cigarette may further comprise a control interface. The control interface may be configured to allow a user to select different heating profiles and the controller may be configured to receive instructions from the control interface and to selectively operate one or more of the heating elements corresponding to the selected heating profile. This arrangement allows the electronic cigarette to receive instructions directly from a user such that the vapor composition is modified according to his/her preferences based on a desired heating profile.

The electronic cigarette may further comprise a communication unit. The communication unit may enable connection and transfer of data from a computing device, the data comprising operating instructions for the heating elements. Such an arrangement may allow further display and configuration options to be provided so that a user has even greater control over the operation of the heating elements, while the structure and components of the electronic cigarette remain simple. The electronic cigarette may further comprise a cartridge detection unit, e.g. a cartridge reader, which may be configured to read an indicium on the cartridge and to send instructions to the controller about the type of cartridge. The indicium may comprise a computer-readable code. The cartridge may comprise a conductive label, which may be configured to be measured by the controller. Such arrangements facilitate the automatic selection of an appropriate heating profile which is adapted to the liquid contained in the cartridge.

The vaporizing unit may be a micro-electro-mechanical-systems (MEMS) vaporizing unit and may be located in the main body portion of the electronic cigarette.

The controller may be configured to execute a calibration cycle, for example to determine which heating element, or group of heating elements, should be activated. The controller may be configured to execute the calibration cycle by activating all of the heating elements and by measuring the electrical resistance of each heating element. Vapor generation can be enhanced by executing the calibration cycle.

The controller may be configured to sequentially activate the heating elements to sequentially heat the corresponding groups of fluidic channels and to indicate to a user which group of fluidic channels is being heated. This enables the user to select a preferred heating element or group of heating elements for activation via the control interface. This arrangement allows a test run to be performed, during which a user can select the mode that is the most satisfactory in terms of vapor production.

The controller may be configured to activate a variable number of heating elements in order to regulate the vapor volume. Such an arrangement allows the volume of vapor generated during use of the electronic cigarette to be carefully controlled and regulated. The vapor volume may be user-selectable. This may provide an enhanced user experience.

The controller may be configured to change the number of activated heating elements and corresponding groups of fluidic channels. Such an arrangement allows a consistent vapor volume to be provided over time, for example by activating one or more additional heating elements in the event that vapor production is diminished due to a build-up of debris/deposits in an already heated group of fluidic channels.

The volume of vapor generated by the electronic cigarette may be proportional to the energy supplied to the heating elements. Thus, the energy supplied to the heating elements after a ramp-up heating time may be indicative of the generated vapor volume. The resistance of the heating element(s) can be monitored at the same time to ensure that there is liquid supply to the fluidic channels and such that vaporization can occur.

Brief Description of the Drawings

Figures 1a and 1b are schematic views of an electronic cigarette according to an embodiment of the present disclosure configured to receive and enclose a replaceable cartridge;

Figure 1c is a schematic cross-sectional view of the electronic cigarette of Figures 1a and 1b;

Figure 2 is a schematic view of an electronic cigarette according to another embodiment of the present disclosure, which is adapted to receive a replaceable cartridge within a mouthpiece portion;

Figures 3a and 3b are schematic views of another embodiment of an electronic cigarette according to the present disclosure, which is provided with a refillable liquid store and a separate vaporizing unit;

Figures 4a and 4b are schematic perspective and side views respectively of different examples of vaporizing unit suitable for use in an electronic cigarette according to the present disclosure; and

Figure 5 is a schematic illustration of an electrical circuit for controlling one or more heating elements of an electronic cigarette according to the present disclosure. Detailed Description of Embodiments

Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings in which like features are denoted with the same reference numerals.

Referring to Figures 1a to 1c, there is shown an electronic cigarette 1 according to an embodiment of the present disclosure. The electronic cigarette 1 comprises a mouthpiece portion 2, a power supply portion 4 and an exterior housing 5. The power supply portion 4 can also be referred to as a main body 4 of the electronic cigarette 1, and is advantageously configured as a re-usable unit. The main body 4 comprises a power supply unit 9 and control circuitry 7 to operate the electronic cigarette 1.

The mouthpiece portion 2 comprises a liquid store 18 containing an aerosol generating liquid and a mouthpiece 6 having an outlet 8 for delivering vapor or aerosol to the user. The mouthpiece portion 2 may further comprise a cartridge seating 10 configured to receive a replaceable cartridge 12 which includes the liquid store 18. The mouthpiece portion 2 can be provided with a separate mouthpiece housing 5a which is configured to connect to a separable main body housing 5b such that the cartridge 12 is enclosed inside the housing 5 of the electronic cigarette 1. The mouthpiece portion 2 and the main body 4 are connectable to each other by a releasable connection 14. The releasable connection 14 can, for example, be a threaded connection or a bayonet connection.

In another embodiment illustrated in Figure 2, the cartridge 12 may be provided with a mouthpiece 6 and a cartridge connector 11 for releasably attaching to a cartridge seating 10 of the main body 4 of the electronic cigarette 1.

Alternatively, as illustrated in Figures 3a and 3b, the electronic cigarette 1 may, instead of the cartridge seating 10 and the cartridge 12, be provided with a refillable liquid store 18 located in the mouthpiece portion 2 of the electronic cigarette 1. The liquid contained inside the liquid store 18 can, for example, be propylene glycol or glycerin and may additionally contain other active ingredients such as nicotine, additives (such as acids) and flavors.

The electronic cigarette 1 further comprises a vaporizing unit 16 configured to vaporize the liquid from the liquid store 18 by heating the liquid to a temperature at which vaporization occurs (typically between 190°C and 290°C). The vaporizing unit 16 can be integrated inside a cartridge 12 together with the liquid store 18, as illustrated in Figure 2. Alternatively, and as illustrated in Figure 3b, the vaporizing unit 16 can be a separate component.

As best seen in Figures 4a and 4b which show different examples of a vaporizing unit 16 suitable for use with the electronic cigarettes 1 described above with reference to Figures 1 to 3, the vaporizing unit 16 is fluidically connectable to the liquid store 18 and comprises at least one heating element 19, and preferably a plurality of heating elements 19. The vaporizing unit 16 also comprises a plurality of fluidic channels 20, for example capillary channels. The vaporizing unit 16 can be configured as a separate part from the cartridge 12 and as a replaceable disposable unit attachable to a vaporizer seating 22 of the main body 4, as shown in Figure 3b. It can be advantageous to exclude the vaporizing unit 16 from the cartridge 12, as this simplifies the structure of the cartridge 12, makes it more economical to produce and facilitates recycling (due to the a more homogenous material construction with a limited amount of metals). However, it is also possible to provide the cartridge 12 with a combined liquid store 18 and an integrated vaporizing unit 16.

As illustrated in Figures 4a and 4b, different forms of the vaporizing unit 16 are possible, as the fluidic channels 20 can be formed by different methods. Common for all illustrated embodiments is that the plurality of fluidic channels 20 is separated into a plurality of groups G1, G2, G3...Gi, wherein each group of fluidic channels G1 to Gi is thermally connected to a separate heating element 19, which can be individually heated to heat a surface 20a of the fluidic channels 20. This configuration is advantageous as it ensures high controllability of the vaporizing unit 16, and a consistent capacity and performance of the vaporizing unit 16 over a longer time period compared to prior art vaporizing units with fluidic channels 20 that are simultaneously heated and not divided into groups that can be heated separately. This is due to the fact that the flow of aerosol generating liquid from the liquid store 18 and through the fluidic channels 20 is reduced as a function of the activation time the vaporizing unit 16, due to debris/deposits building up over time in the fluidic channels 20.

In a first example illustrated in Figure 4a, the fluidic channels 20 can be configured as tubular (closed) channels 20 arranged inside a block-shaped component 24. The block-shaped component 24 may be formed from electrically conductive material such as silicon, doped ceramic, metal-ceramic, filter ceramic, semiconductor, germanium, graphite, semi-metal and/or metal. The fluidic channels 20 can be heated along their entire length via their outer surface 20a, or alternatively only at their outlets 26. In the former case, resistive heating elements 19 can be embedded in the block-shaped component 24 so that they extend along the length of the fluidic channels 20 and are substantially parallel thereto. The vaporizing unit 16 may also comprise electrical connectors (not shown), configured to electrically connect the vaporizing unit 16 to the power supply unit 9 and control circuitry 7.

In a second example illustrated in Figure 4b, the fluidic channels 20 can be formed by plates 32. The plates 32 are provided at a distance d from each other in order to create a gap sufficient to draw liquid into the fluidic channels 20 from the liquid store 18 by capillary action. One or more of the plates 32 are preferably heatable and can be provided in a high-resistivity material, for instance Titanium, Nickel, Chrome, Stainless steel or an alloy including at least one of these materials. The plates 32 are provided with a first end 34 configured for electrical connection to the power supply unit 9 and control circuitry 7 and a second end 36 configured as a vapor outlet. The vaporizing unit 16 can thus be formed as an elongate extension of heatable plates 32. The plates 32 may be held together as a stack by at least one insulating element 40. The stacked structure can be easily assembled as plates 32 stacked side-by-side and enables small fluidic channels 20 to be formed in a simple manufacturing process and with precision. To enable groups of the fluidic channels 20 to be separately heated, the vaporizing unit 16 comprises fluidic channels 20 thermally connected together in at least three different groups; a first group G1, a second group G2 and a third group G3. However, there can be more than three groups, if desired, for example as shown in Figure 4a. Each group G1 to Gi may comprise any desired number of fluidic channels 20.

To achieve an accurate control of the vaporizing unit 16, the vaporizing unit 16 and the control circuitry 7 may be configured as a micro-electro-mechanical-systems (MEMS) component. The MEMS component structure provides a compact control circuitry to control the flow and vaporization from the fluidic channels 20. This further enables the electronic cigarette 1 to precisely control parameters such as vapor volumes and particle size.

Each group G1 to Gi of fluidic channels 20 is preferably configured to be operated (or heated) in a uniform way. To this effect, each group G1 to Gi of fluidic channels 20 is preferably heated by a corresponding one of the heating elements 19 (H1 to Hi).

The control circuitry 7 is further configured to set the heating elements H1 to Hi into different operating states, the operating states comprising activation, standby and deactivation. The control circuitry 7 is also configured to change the operating states of the different heating elements H1 to Hi over time.

The plurality of groups G1 to Gi of fluidic channels 20 enable the electronic cigarette 1 to provide a consistent amount and composition of vapor over time. This addresses the problem that over time, some of the fluidic channels 20 may become obstructed due to debris/deposits building up within the fluidic channels 20. If an obstructed fluidic channel 20 continues to be heated, a reduced amount of vapor is produced while the temperature increases (due to reduced flow of aerosol generating liquid through the fluidic channel 20) and the composition of the vapor may degrade and become unpleasant to the user. Having a plurality of groups G1 to Gi of fluidic channels 20 enables a sequential activation, thus creating a backup capacity in the vaporizing unit 16.

With reference to the schematic illustration of the electrical circuit shown in Figure 5, this is achieved by a controller 50 in the control circuitry 7 which is connected to and configured to selectively activate switches S1 to Si connected to a corresponding one of the heating elements H1 to Hi. The control circuitry 7 can comprise a first switch S1 that automatically deactivates the heating element H1 when the fluidic channels 20 in the corresponding first group G1 are determined to be obstructed.

Initially a first group G1 of fluidic channels 20 can be heated by closing the switch S1 to activate the corresponding heating element H1, while a second group G2 and a third group G3 of fluid channels 20 are deactivated. Then, once the first group G1 of fluidic channels 20 is determined to be obstructed, the at least one heating element H 1 in thermal contact with the first group G1 of fluidic channels 20 can be switched to a deactivated/standby state by opening the switch S1 and a second heating element H2 in thermal contact with a second group G2 of fluidic channels 20 can be activated by closing the switch S2. During this time, the third group of fluidic channels G3 can be in a standby mode which ensures the production of vapor for another, later, time interval.

The control circuitry 7 can be configured to determine the amount of time for which each group G1 to Gi of fluidic channels 20 should be heated by the corresponding heating elements H1 to Hi.

According to a first embodiment, the controller 50 can determine the obstruction of the fluidic channels 20 by measuring the period of time for which each group G1 to Gi of fluidic channels 20 has been heated. The control circuitry 7 further comprises a memory 52 configured to store a time threshold. The time threshold may advantageously be based on historical data of the vaporizing unit 16 and for different types of aerosol generating liquids to provide threshold data on the average time that the fluidic channels 20 typically take to become obstructed. Additionally, to provide an even more accurate estimation, the applied temperature setting and variations thereof over time can be measured by the controller 50 and included in the data to be compared against the threshold data. The temperature has an impact on the obstruction, as the higher the temperature used, the more debris is usually formed in the fluidic channels 20.

Alternatively, the memory 52 of the control circuitry 7 may contain instructions regarding the selection of type of operating mode and the duration. This will automatically enable the execution of a program determining a default program of how long each group G1 to Gi of fluidic channels 20 could be heated before they are deemed to be obstructed and should be disabled by the controller 50. Hence, the controller 50 is configured to calculate an allowable amount of operating time based on a plurality of characteristics (including, e.g., temperature setting and liquid type) and to disable the corresponding heating element H1 to Hi via the corresponding switch S1 to Si once the time has elapsed. This saves processing capacity from the control circuitry 7, as no continuous measurement other than time is needed.

As another alternative, the control circuitry 7 may be configured to measure the electrical resistance of a heating circuit associated with each of the groups G1 to Gi of fluidic channels 20 in operation and to compare a measured resistance value Rm with a reference value Rv. The measured resistance value Rm is indicative of the level of obstruction in the fluidic channels 20. The electrical resistance of the heating circuit increases with a higher temperature. Hence, an increased temperature (and increased resistance) is indicative of an absence of liquid or an obstruction in the fluidic channel 20, as liquid present in the fluidic channels 20 tends to cool the heating element H1 to Hi as energy from the heating element H1 to Hi is consumed in the vaporization of the liquid. The controller 50 may therefore be configured to measure the current flow and/or the electrical resistance of each group of heating circuits. This has the advantage that both the vapor production and the presence of liquid can be precisely monitored.

In the embodiment where the controller 50 is configured to measure the electrical resistance of the heating element H1 to Hi, the memory 52 contains a resistance threshold, such that the controller 50 can disable the heating element H1 to Hi when the measured resistance corresponds to the threshold.

In yet another embodiment, the electronic cigarette may further comprise a communication unit 56, via which data comprising operating instructions for the heating elements H1 to Hi can be transferred from a computing device to the controller 50.

Another advantage of the present disclosure is that the vapor volume can be modified by the controller 50. The user may for instance want to vary the amount of vapor or aerosol delivered by the electronic cigarette 1. The controller 50 may therefore also be configured to activate a variable number of groups H1 to Hi of heating elements 19 to simultaneously heat a plurality of groups G1 to Gi of fluidic channels 20.

The electronic cigarette 1 may also be configured to heat different groups G1 to Gi of fluidic channels 20 simultaneously, but at different temperatures. This would enable the rinsing of some channels 20 in a ‘cleaning mode’ while the main vapor volume is generated by heating aerosol generating liquid flowing through one or more other groups G1 to Gi of the fluidic channels 20.

The electronic cigarette 1 may be further configured to provide different heating profiles for different types of liquids and flavors. The aerosol generating liquid typically comprises a mix of propylene glycol (PG) and vegetable glycerin (VG). When these liquids are mixed, the boiling point of the composition corresponds to a combination of the respective boiling points. The new boiling point of the combined liquid formulation is then different from the individual boiling points of the original liquids.

Typically, propylene glycol has a boiling point 188.2°C and a viscosity of 0.042 Pa s. Glycerin on the other hand has a boiling point 290°C and a viscosity of 1.412 Pa s. Capillary penetration in the fluidic channels 20 is resisted by viscous forces. These significant differences impact the ease with which the liquid can flow through the fluidic channels 20.

Because of the variation of vaporization temperature between liquids, the temperature setting of the heating elements 19 should preferably be adapted to the vaporization temperature of the liquid composition.

To accommodate aerosol generating liquids having different viscosities, the fluidic channels 20 can be arranged in groups G1 to Gi where each group is provided with a different cross-sectional area. For example, one group G1 of fluidic channels 20 could work best with a first liquid and another group G2 with a second liquid. This allows the vaporizer to adapt to different liquid compositions, as Propylene Glycol and Vegetable Glycerin and combinations thereof have widely spread different viscosities and boiling temperatures. Each of the different groups G1 to Gi of fluidic channels 20 may include channels 20 having different diameters.

The control circuitry 7 of the electronic cigarette 1 is further configured to enable selective activation of the groups of channels G1 to Gi depending on the type of liquid.

The type of liquid can either be manually inputted on a control interface 54 of the electronic cigarette 1, or on a remote computing device (e.g. a smartphone-type device with Bluetooth connection) connected via wired or wireless link to the control circuitry 7 of the electronic cigarette 1. Alternatively, the electronic cigarette 1 may comprise a cartridge detection unit 60 configured to sense the type of cartridge and thus the type of liquid. For example, the cartridge detection unit 60 may comprise a cartridge reader which is configured to read an indicium (such as a computer- readable code) on a cartridge 12 and to send instructions to the controller 50 about the type of cartridge 12.

Furthermore, the use of different flavors also has an impact on the vaporization temperature, because each type of flavor has a different ideal vaporization temperature. This is because larger particle sizes stay in the sensory area in the user’s mouth, while smaller sized particles travel deeper into the user’s lungs.

Different particle sizes can be achieved by controlling any one or more of:

• the size (e.g. cross-sectional area) of the fluidic channels 20;

• the length of the fluidic channels 20;

• the temperature of the heating elements 19 (and, hence, the vaporization temperature);

• the temperature of the generated vapor (because when the temperature decreases, the vapor condenses by particles adhering to each other); and

• the flow of vapor, e.g. the speed of vapor in the fluidic channels 20.

The use of different flavors in combination with different ratios of propylene glycol and vegetable glycerin have different optimal temperatures where the sensory effect is best experienced.

The vaporizing unit 16 is configured to produce a consistent and controlled particle size. The temperature and the size of outlets 26 of the fluidic channels 20 define the particle size. The vaporizing unit 16 can therefore be provided with groups G1 to Gi of fluidic channels 20 having different sized (e.g. diameter) outlets 26. The length of the fluidic channels 20 may also be different from one group of channels 20 to another.

The memory 52 can also include indications of which liquid type is to be used with which heating element H1 to Hi, i.e. , with which group G1 to Gi of fluidic channels 20.

Alternatively, the controller 50 can be configured to calibrate the vaporizing unit 16 to determine which heating elements H1 to Hi should be used for heating the aerosol generating liquid. This can be achieved by a calibration cycle in which all of the heating elements H1 to Hi are activated to heat all of the corresponding groups G1 to Gi of fluidic channels 20, and wherein the resistance and temperature is defined. Alternatively, a test run can be activated during which the user can select the mode that is the most satisfactory.

The skilled person will realize that the present disclosure is by no means is limited to the described exemplary embodiments. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Moreover, the expression "comprising" does not exclude other elements or steps. Other non-limiting expressions include that "a" or "an" does not exclude a plurality and that a single unit may fulfil the functions of several means. Any reference signs in the claims should not be construed as limiting the scope. Finally, while the disclosure has been illustrated in detail in the drawings and in the foregoing description, such illustration and description is considered illustrative or exemplary and not restrictive; the disclosure is not limited to the disclosed embodiments.

Claims

1. An electronic cigarette (1) comprising a vaporizing unit (16) and a liquid store (18), wherein: the vaporizing unit (16) comprises a plurality of fluidic channels (20) configured to receive liquid from the liquid store (18), a surface (20a) of the fluidic channels (20) is configured to be heated to vaporize liquid in the fluidic channels (20), the fluidic channels (20) are separated into a plurality of groups (G1 to Gi), each group (G1 to Gi) of fluidic channels (20) is thermally connected to a separate heating element (19), and the groups (G1 to Gi) of fluidic channels (20) have different cross-sectional areas.

2. The electronic cigarette according to claim 1, wherein the length of the fluidic channels (20) in one group is different from the length of the fluidic channels (20) in another group.

3. The electronic cigarette according to claim 1 or claim 2, further comprising a controller (50) configured to selectively operate one or more of the separate heating elements (19) to selectively heat one or more of the corresponding groups (G1 to Gi) of fluidic channels (20).

4. The electronic cigarette according to claim 3, further comprising a control interface (54) configured to allow a user to select different heating profiles and wherein the controller (50) is configured to receive instructions from the control interface (54) and selectively operate one or more of the heating elements (19) corresponding to the selected heating profile.

5. The electronic cigarette according to claim 4, further comprising a communication unit (56) enabling transfer of data from a computing device, said data comprising operating instructions for the heating elements (19).

6. The electronic cigarette according to any of claims 3 to 5, further comprising a cartridge detection unit (60), configured to read an indicium on a cartridge (12) and send instructions to the controller (50) about the type of cartridge (12).

7. The electronic cigarette according to claim 6, wherein the indicium comprises a computer-readable code.

8. The electronic cigarette according to any of claims 3 to 7, wherein the cartridge (12) comprises a conductive label, configured to be measured by the controller (50).

9. The electronic cigarette according to any of claims 3 to 8, wherein the controller (50) is configured to execute a calibration cycle to determine which heating element (19), or group of heating elements (19), should be activated.

10. The electronic cigarette according to claim 9, wherein the controller (50) is configured to execute the calibration cycle by activating all of the heating elements (19) and by measuring the electrical resistance of each heating element (19).

11. The electronic cigarette according to claim 10, wherein the controller (50) is configured to sequentially activate the heating elements (19) to sequentially heat the corresponding groups (G1 to Gi) of fluidic channels (20) and to indicate to a user which group (G1 to Gi) of fluidic channels (20) is being heated, enabling the user to select a preferred heating element (19) or group of heating elements for activation via the control interface (54).

12. The electronic cigarette according to any of claims 3 to 11, wherein the controller (50) is configured to activate a variable number of heating elements (19) in order to regulate the vapor volume.

13. The electronic cigarette according to claim 12, wherein the vapor volume is user-selectable.

14. The electronic cigarette according to claim 12 or claim 13, wherein the controller (50) is configured to change the number of activated heating elements (19) and corresponding groups (G1 to Gi) of fluidic channels (20) in order to provide a consistent vapor volume over time.