WO2023186606A1

WO2023186606A1 - Vapour generating systems

Info

Publication number: WO2023186606A1
Application number: PCT/EP2023/057074
Authority: WO
Inventors: Alec WRIGHT
Original assignee: Jt International Sa
Priority date: 2022-04-01
Filing date: 2023-03-20
Publication date: 2023-10-05
Also published as: CN118890978A

Abstract

An aerosol generating system comprises a cartridge (2) that contains a supply of aerosol generating material (15) and an aerosol generating device (4) for receiving the cartridge (2). When the cartridge (2) is received in the aerosol generating device (4), projections (38) on the cartridge (2) enter a set of recesses (40) in the device (4) and exert pressure on a pressure-responsive surface (20) disposed in the base of the recesses (40), whereby the correct insertion of an authentic cartridge (2) can be determined. The pressure-responsive surface (20) may be part of a plate (50) that moves in response to the exerted pressure to complete an electrical power circuit or a test circuit. Preferably, the pattern of recesses (40) requires the complementary projections (38) to be arranged in the shapes of letters, symbols or other patterns capable of conveying visual information, for example a trade mark of the supplier of authentic cartridges (2).

Description

VAPOUR GENERATING SYSTEMS

Technical Field

The present disclosure relates generally to aerosol generating systems configured to convert an aerosol generating material into an aerosol for inhalation by a user of the system. More specifically, it relates to ensuring that aerosol generating devices may only be used with authorized aerosol generating cartridges.

Technical Background

The term aerosol generating system (or more commonly electronic cigarette or e-cigarette) refers to handheld electronic apparatus that is intended to simulate the feeling or experience of smoking tobacco in a traditional cigarette. Electronic cigarettes typically work by heating an aerosol generating liquid to generate a vapour that cools and condenses to form an aerosol which is then inhaled by the user. Accordingly, the use of e-cigarettes is also sometimes referred to as “vaping”. The aerosol generating liquid usually comprises nicotine, propylene glycol, glycerine and flavourings.

Typical e-cigarettes comprise vaporizing units, i.e. systems or sub-systems for vaporizing the aerosol generating liquid by utilizing a heating element to produce vapour from liquid stored in a capsule, tank or reservoir. When a user operates the e- cigarette, liquid from the reservoir is transported through a liquid transfer element, e.g. a cotton wick or a porous ceramic block, and is heated by the heating element to produce a vapour, which cools and condenses to form an aerosol that can be inhaled. To facilitate the ease of use of e-cigarettes, removable cartridges are often employed. These cartridges are often configured as “cartomizers”, which means an integrated component comprising a liquid store, a liquid transfer element and a heater. Electrical connectors may also be provided to establish an electrical connection between the heating element and a power source. Such cartridges may be disposable, i.e. not intended to be capable of reuse after the supply of liquid in the reservoir has been exhausted. Alternatively, they may be reusable, being provided with means allowing the reservoir to be refilled with a new supply of vapour generating liquid.

By using alternative technologies such as jet heads or nebulizers, it may be possible to generate droplets directly from the liquid, which are of a suitable size to form an aerosol without the need to go through the intermediate stage of forming a vapour and perhaps without heating the liquid at all. In some cartridges, the aerosol generating liquid may be absorbed in a solid material or the aerosol generating material may itself be a solid, such as a gel, from which liquid or vapour can be evolved by heating. The use of such technologies is not excluded from the application of the present invention, which relates to authentication of the cartridge and not to the method of aerosol generation.

A cartridge for an e-cigarette typically comprises an air inlet at a first end and an air outlet at a second, opposite end. (Considered from the viewpoint of a user of the system, the first end of the cartridge may also be termed the distal end and the second end of the cartridge may also be termed the proximal end or mouth end.) The first end of the cartridge is configured to be releasably connected to a main body of the aerosol generating system, which may, for example, contain a power source and control electronics. A user inhales through a mouthpiece at the second end of the cartridge to draw air along an airflow path from the air inlet to the air outlet. The airflow path passes through an aerosol generating chamber, where vapour or droplets formed from the liquid are mixed with the air to form an aerosol.

In use, such a cartridge is received in an aerosol generating device to form the complete aerosol generating system. The aerosol generating device is typically not disposable, i.e. it is intended to be re-used multiple times with different cartridges. The device comprises a body by which it may be held by a user and contains a source of power for the heater in the cartridge, as well as control circuitry. The device may further comprise means such as buttons for the user to input commands to the aerosol generating system and/or means such as lights or a display screen for the system to output information to the user. Additionally or alternatively, the device may comprise means for communicating with an external device, such as a mobile phone, which provides an interface for the user to interact with the aerosol generating system.

There exists a desire that certain aerosol generating devices should be capable of use only with authentic cartridges, which originate from or are authorized by the manufacturer or supplier of the device. This is not only to protect the supplier’s market in the sale of replacement cartridges. It also allows the supplier to ensure that the device is able to control the operation of the cartridge in an appropriate way, which complies with accepted safety standards for the user (e.g. relating to the operating temperature of the cartridge and the substances contained in the aerosol that is generated) and does not risk damage to the device itself (e.g. by drawing excess current from the power supply or by leakage of aerosol generating liquid from a poorly designed cartridge). Preferably, a system that allows an aerosol generating device to detect or disable inauthentic cartridges, would also allow such inauthentic cartridges to be detected by visual inspection by humans.

A prior art aerosol generating system that is capable of detecting an inauthentic cartridge is disclosed in Chinese utility model CN 212306822 U. Authentication of the cartridge is performed by a camera assembly in the device, which records an “anti-fake sign indicating number” on a mating face of the cartridge. The provision of a camera and of software that is capable of identifying whether the imaged number represents an authentic cartridge would add significantly to the cost of the device. A cheaper and simpler system is therefore desirable.

Summary of the invention

The invention provides an aerosol generating system comprising a cartridge that contains a supply of aerosol generating fluid, and an aerosol generating device for receiving the cartridge; wherein the cartridge comprises one or more projections; the aerosol generating device comprises one or more recesses configured to receive the one or more projections when the cartridge is received in the aerosol generating device; and the aerosol generating device further comprises a pressure-responsive surface disposed in the base of a first set of one or more of the recesses for detecting pressure exerted by one or more of the projections when received in the first set of recesses. In preferred embodiments, the pressure-responsive surface is a surface of a plate that is configured to move in response to pressure applied to the pressure-responsive surface and thereby to complete an electrical circuit.

In order for the projections of the cartridge to exert pressure on the pressure-responsive surface disposed in the base of the recesses, the pattern of the projections must complement the pattern of the recesses. This provides a way of ensuring that with any given aerosol generating device, only cartridges that comprise a complementary set of conducting elements can be used. If an inauthentic cartridge with a different pattern of conducting elements is used, either the cartridge will not fit to the device at all or, for example, if the projections are simply omitted from the cartridge to avoid interference, then no pressure will be applied to the pressure-responsive surface and the device will be able to determine that an inauthentic cartridge has been attached. The controller of the device can then take appropriate action, such as issuing a warning to the user or blocking the supply of power to the cartridge. While forming the projections, recesses, and control electronics capable of responding to pressure applied to the pressure- responsive surface will add somewhat to the complexity and cost of assembling the device and the cartridge, these are simple mechanical/ electrical components that can be easily integrated into a conventional assembly process. The invention does not require the addition of expensive components such as cameras or significant additional software or processing power.

The plate may be mounted so that pressure applied unevenly to the pressure-responsive surface may cause the plate to tilt and thereby fail to complete the electrical circuit. This arrangement may thus be able to determine not only whether the total pressure exerted by the projections of the cartridge has reached a predetermined level but also whether the pressure is exerted with the expected distribution across the area of the pressure-responsive surface. This has the advantage that the device can identify if an inauthentic cartridge is attached, which comprises some but not all of the required pattern of projections. In common with many known aerosol generating systems, the cartridge may comprise an electrically powered aerosol generator, such as a heater, and the aerosol generating device may comprise a source of electrical power. In preferred embodiments of the invention, in which a plate that is configured to move in response to pressure applied to the pressure-responsive surface and thereby to complete an electrical circuit, the electrical circuit may be configured, when complete, to supply current from the power source to the aerosol generator. Accordingly, if the device is used with an inauthentic cartridge, such that the projections of the cartridge are not in a pattern complementary to the recesses of the device, the electrical circuit will not supply current from the power source to the aerosol generator. It follows that the inauthentic cartridge will automatically be prevented from being used with the device to generate an aerosol.

Alternatively, if the aerosol generating device comprises a source of electrical power and a controller, the controller may be configured to supply current from the power source to the electrical circuit to verify that the cartridge is received correctly in the aerosol generating device. Thus the electrical circuit serves as a test circuit. If the device is used with an inauthentic cartridge, such that the projections of the cartridge are not in a pattern complementary to the recesses of the device, a continuous conductive path will not be formed through the electrical circuit. If the controller does not detect the flow of current through the test circuit it can determine that the cartridge is not authentic or that it has not been inserted correctly and it can take appropriate action, such as disabling the supply of power to the cartridge and/or generating a warning to the user.

The test circuit is not necessarily distinct from the circuit for supplying power to the heater. If a common circuit is used then, when the cartridge has been inserted into the device, the controller would first attempt to send a small test current through the test/power circuit in order to confirm whether the cartridge is authentic and has been inserted correctly. Only if those conditions are satisfied will the controller deliver the higher current required to power the heater. Providing the pressure-responsive surface as the surface of a plate is technically simple and therefore potentially cheap to manufacture. However, it can act like an on/off switch to indicate simply whether a required level of pressure is applied, rather than being capable of outputting a measurement of the pressure. In an alternative embodiment, the pressure-responsive surface may form part of a pressure sensor or may be engaged with a pressure sensor, which is configured to generate a signal when pressure is applied to the pressure-responsive surface. Pressure sensors are now available that are small and relatively cheap so they provide a practical and efficient way of determining the pressure applied by the projections of the cartridge on the pressure-responsive surface of the device.

Such a pressure sensor may be capable of generating different signals when pressure is applied to different regions of the pressure-responsive surface. Thus the sensor may be able to discriminate not only the total pressure exerted by the projections of the cartridge but, at least at low resolution, the distribution of pressure across the area of the pressure-responsive surface. This has the advantage that the device can identify if an inauthentic cartridge is attached, which comprises some but not all of the required pattern of projections.

The aerosol generating device preferably comprises a controller, the controller being configured to activate the aerosol generating system selectively in response to a signal from the pressure sensor. Providing a pressure sensor that can convert the presence or absence of pressure (and optionally the amount of the pressure) to an electronic signal makes it easy for an electronic control circuit to receive, process and respond appropriately to the signal.

In some embodiments of the invention, the first set of recesses comprises a plurality of recesses, and may comprise all the recesses. Thus there is only a single pressure- responsive surface disposed in the base of one or more of the recesses, which extends across the bases of the one or more of the recesses. This operates as previously described. Alternatively, the aerosol generating system may comprise a second pressure- responsive surface disposed at the base of a second set of one or more of the recesses for detecting pressure exerted by one or more of the projections when received in the second set of recesses, the second set of recesses being distinct from the first set of recesses. Thus, whether the pressure-responsive surfaces are configured as pressure sensors or as pressure-sensitive switches, they are respectively associated with different sets of the recesses. This arrangement is capable of determining whether the pressure exerted by the projections of the cartridge has reached a predetermined level on each of the two or more pressure-responsive surfaces. This has the advantage that, to be recognized as authentic, a cartridge must comprise projections that correspond to each set of the recesses. Therefore it becomes harder of a manufacture of inauthentic devices to circumvent the verification by omitting some of the projections.

Preferably, the projections are in the shapes of letters, symbols or other patterns capable of conveying visual information. From the information conveyed by the pattern of recesses, a human observer can easily recognize whether or not the cartridge is authentic. For example, the pattern might be a distinctive name, logo or other sign by which the supplier of authentic cartridges is recognized. This example provides the further advantage that such a sign can often be legally protected as a registered trade mark or through other intellectual property rights such as copyright. Therefore, in order for a competing manufacturer to supply inauthentic cartridges that are capable of operating with a genuine device, that manufacturer must necessarily form the projections of the cartridge that in a pattern that replicates the protected sign. Intellectual property laws can thereby be used to prevent the distribution and sale of the inauthentic cartridges.

The invention further provides a method of activating an aerosol generating system that comprises a cartridge, which contains a supply of aerosol generating material and comprises one or more projections; and an aerosol generating device for receiving the cartridge, the aerosol generating device comprising one or more recesses and a pressure-responsive surface disposed in the base of a first set of one or more of the recesses; the method comprising inserting the cartridge into the aerosol generating device such that one or more of the projections are received in the first set of recesses; and activating the aerosol generating system when the pressure-responsive surface detects pressure exerted by the projections received in the first set of recesses.

As previously explained, this ensures that with any given aerosol generating device, one can only use authentic cartridges, which comprise a set of projections that is complementary to the pattern of recesses of the device. Other cartridges will not apply the expected pressure to the pressure-responsive surface and can thereby be identified as inauthentic.

Preferably, the pressure-responsive surface is a surface of a plate that is configured to move in response to pressure applied to the pressure-responsive surface and thereby to complete an electrical circuit. The step of activating the aerosol generating system may be carried out in response to completion of the electrical circuit.

Alternatively, the pressure-responsive surface is part of a pressure sensor or is engaged with a pressure sensor; and the step of activating the aerosol generating system is carried out in response to a signal generated by the pressure sensor.

In this specification, “authentication” or “verification” is the process of determining whether a cartridge received in the aerosol generating device is an authentic cartridge according to criteria determined by the manufacturer or supplier of the device. The outcome of authentication or verification may accordingly be positive or negative.

Description of the drawings

Figure 1 is a schematic diagram of an aerosol generating system according to the prior art, of a kind with which the present invention may be used.

Figure 2 is a schematic section through a cartridge and part of a device according to a first embodiment of the invention, before insertion of the cartridge into the device. Figure 3 is an end view of the cartridge of Fig. 2.

Figure 4 is an end view of the device of Fig. 2. Figure 5 is a schematic section through part of a device according to a second embodiment of the invention.

Figure 6 is a schematic section through part of a device according to a third embodiment of the invention.

Figure 7 is a schematic section through part of a device according to a fourth embodiment of the invention.

Figure 1 illustrates the general arrangement of an aerosol generating system, of a kind with which the present invention may be used. The system comprises a replaceable cartridge 2, which is removably attached to or received in an aerosol generating device 4. The aerosol generating device 4 comprises a housing 6, which contains a power source 8, such as a rechargeable battery, and a control circuit 10, which receives power from the power source 8 and selectively delivers it to a pair of electrical terminals 12 facing the cartridge 2. The device 4 may further comprise components that are not illustrated, including (without limitation) any or all of the following:

• buttons, switches or a touch-sensitive screen on the exterior of the housing 6, by which the user can input commands to the aerosol generating system;

• indicator lights or a display screen on the exterior of the housing 6, by which the aerosol generating system can output information to the user;

• communication means, e.g. a port or a wireless antenna, by which the aerosol generating system can exchange data with an external device such as a user’s mobile phone or a manufacturer’s customer support system.

The cartridge 2 is engaged with the aerosol generating device 4, to which it may be removably secured by magnetic and/or mechanical means (not illustrated) such as magnets, clips, a bayonet and/or screw fitting. The cartridge 2 may be fitted onto the housing 6 of the device 4 in an end-to-end arrangement as shown, or it may be received in a cavity in the housing 6, for example behind a cover (not illustrated).

The cartridge 2 comprises a reservoir 14, which contains a supply of aerosol generating liquid 15. The cartridge 2 further comprises an airflow path 16 from an air inlet 18 to a mouthpiece 20. The mouthpiece 20 may be integral with the cartridge 2, may be removably attached to the cartridge 2 or, in systems in which the cartridge 2 is received inside the housing 6 of the device 4, the mouthpiece 20 may form part of the device 4.

The cartridge 2 further comprises electrically powered means for generating an aerosol from the liquid 15. In the illustrated embodiments of the invention, the aerosol generator comprises a simple resistance heater 22 with a coil wrapped around a liquid- permeable wick 23. The heater 22 is disposed in the airflow path 16, possibly in a dedicated heating chamber (not illustrated). Liquid 15 from the reservoir 14 steadily permeates through to the surface of the wick 23, where it is heated by the heater 22 and evaporates as a vapour into the airflow path 16. As inhaled air flows along the airflow path 16 from the heater 22 towards the mouthpiece 20, the vapour mixes with it, cools and condenses into droplets, forming an aerosol that is suitable for the user to breathe in. Even with a resistance heater 22, the cartridge 2 and its components may be configured in ways very different from that illustrated. Moreover, other resistive heating solutions, such as ceramic heaters, planar die cut or printed resistive heaters or heating technologies and corresponding heater elements or systems, such as induction, may be used instead of the represented coil and wick resistive heater 22 to increase the temperature of the liquid. Aerosol generation may further be based on alternative aerolization technologies, such as nebulization, which do not necessarily require heating of the liquid 15 and that generate or inj ect suitably sized droplets of the liquid 15 directly into the airflow path to form an aerosol without heating the liquid. All of these variants are intended to fall within the scope of the invention, which is not concerned with the particular apparatus or method by which the aerosol is generated.

The heater 22 or other aerosol generator is coupled between a pair of terminals 24 on an external surface of the cartridge 2 that faces towards the device 4. Thereby, when the cartridge 2 is received in the device 4, the respective terminals 12,24 are brought into contact and complete a circuit that can deliver power from the power source 8 in the device 4 to aerosol generator 22 in the cartridge under the control of the control circuit 10. Figure 2 schematically shows a cartridge 2 according to a first embodiment of the invention, together with the proximal end of a device 4 that is to receive the cartridge 2. As in Figure 1, the cartridge 2 comprises a reservoir 14 that delivers a supply of aerosol generating liquid 15 to a wick 23. A heater 22 vaporizes the liquid 15 from the surface of the wick 23 such that the generated vapour mixes with air in an airflow path 16 and condenses to form an aerosol. The air inlet of the airflow path 16 is not visible in Figure 2 because it lies outside the plane of the drawing. Also as in Figure 1, the heater 22 is electrically connected to a power source in the device 4 (not shown in Figure 2) via a pair of terminals 24 on the cartridge 2 that engage with a respective pair of terminals 12 on the device 4. The device terminals 12 may be in the form of springmounted “pogo pins” to ensure good contact pressure at the junction of terminals 12,24.

In accordance with the invention, the engagement between the cartridge 2 and the device 4 comprises a set of projections 38 on the cartridge 2 that are received in a complementary set of recesses 40 in the device 4. The projections 38 on the cartridge 2 form a distinctive pattern such as a word or logo: in this case, the word “Logic”, as seen in Figure 3. The recesses 40 in the device 4 form the complementary pattern, namely the inverted word “Logic”, as seen in Figure 4. In order for a cartridge 2 to operate with the device 4, it must comprise a pattern of projections 38 that are complementary to the recesses 40, therefore it must bear the same word “Logic”, which can be read by an observer viewing the distal end of the cartridge when not in use. Figure 2 shows the projections 38 and the recesses 40 being of substantially equal width. Of course, the recesses 40 must be slightly wider than the projections 38 in order to accommodate them. It is preferred that the recesses 40 should not be too much wider than the projections 38 because this would permit a greater range of variation in the pattern of the projections 38.

The distinctive pattern of the recesses 40 that is required for the cartridge 2 to operate with the device preferably comprises letters or symbols that convey information about the cartridge 2. For example, the pattern may be a brand name or logo that identifies the supplier both of the device 4 and of authentic cartridges 2 for use with it, whereby a potential purchaser or any other person can immediately recognize whether a given cartridge is capable of use with the device 4. Preferably, the pattern is one that has legal protection through intellectual property rights, such as a registered trade mark or a copyright work. Thereby, if an inauthentic cartridge 2 is provided with the pattern of projections 38 required to fit to the device 4, it will infringe those rights and the rights owner can take legal action to prevent the supply of such cartridges 2.

In accordance with the invention, the aerosol generating device 4 further comprises a pressure-responsive surface 20 disposed in the base of one or more of the recesses 40. In the embodiment of Figure 2, the pressure-responsive surface 20 extends across the bases of all the recesses 40 and is the active surface of a pressure sensor 30. The projections 38 of the cartridge 2 are slightly longer than the depth of the recesses 40 so that, when the cartridge 2 is correctly coupled to the device 4, the projections 38 exert pressure on the pressure-responsive surface 20, which can be detected by the sensor 30. The preferred type of sensor 30 is a capacitive pressure sensor because they are low power and are sensitive at low pressure. They are also robust, low cost and can be made on the MEMS scale making them suitable for this application. Piezoelectric sensors may also be suitable; they have a higher sensitivity but higher complexity and cost.

Figure 2 schematically shows a pair of terminals 32 by which the pressure sensor 30 can communicate with the control circuit 10, in particular to communicate the output of the pressure sensor 30 to control circuit 10, which can thereby make a determination of whether the cartridge is authentic and can activate or disable the heater 22 to generate an aerosol upon demand by the user. Because a simple yes or no determination is needed, it may be sufficient for the sensor 30 to emit a binary signal representing the presence or absence of pressure. In practice, most pressure sensors 30 emit a signal that represents the level of pressure applied. From this, the control circuit can determine that an authentic cartridge 2 is attached when the detected pressure exceeds a predetermined threshold.

A simple pressure sensor 30 may be insensitive to where on the pressure-responsive surface 20 the pressure is applied. Therefore, it might be possible for an inauthentic cartridge to circumvent the authentication process by being provided with a reduced number of projections that apply pressure to only some parts of the surface 20. The pattern of such projections 38 might not match the protected pattern that is exclusive to the manufacturer of authentic cartridges. More sophisticated pressure sensors 30 may avoid this problem by giving an output that represents both the level of pressure and its location or distribution on the pressure-responsive surface 20. For the highest security, a control circuit 10 responsive to such a sensor could be configured to authenticate the cartridge 2 based on recognizing, at some desired level of resolution, the two- dimensional pattern of the pressure exerted by the projections 38. Figure 5 shows an alternative solution, in which first and second pressure sensors 30 are provided at the bases of respective first and second sets of the recesses 40. The output of each pressure sensor 30 is communicated independently to the control circuit 10, which may determine that an authentic cartridge 2 has been inserted in the device only if pressure is simultaneously detected by both sensors 30. Thereby the cartridge must comprise at least some projections 38 in locations corresponding to recesses 40 of the first set and the second set. It will easily be understood how this concept could be extended to an array of more than two pressure sensors 30 disposed across the bases of respective sets of the recesses 40 in different regions of the pattern. With an increasing number of pressure sensors 30, it becomes increasingly difficult for a counterfeiter to design a pattern of projections 38 that differs substantially from the protected pattern, while remaining capable of activating all the pressure sensors 30 simultaneously.

Figure 6 schematically shows a further embodiment of the invention, which differs from the previous embodiments in that the pressure responsive surface 20 is a surface of a movable plate 50. The plate 50 is mounted on one or more biasing elements 52 in a cavity 54 in the device 4 and is configured to move against the restoring force of the biasing elements 52 when pressure is exerted on the pressure-responsive surface 20. The biasing elements 52 are illustrated as coil springs but may be other elastic or resilient elements that will deform when pressure is applied to the pressure-responsive surface 20 and return the movable plate 50 to its initial position when the pressure is released. An electrical conductor 56 extends across the movable plate 50. Two terminals 58 of a test circuit are exposed in the cavity 54 such that, when the plate 50 moves in response to applied pressure, the conductor 56 can be brought into contact with the two terminals 58 and complete the test circuit. The test circuit is coupled to the control circuit 10 (not shown in Figure 6), which can thereby apply a voltage to the test circuit. If current is able to flow through the test circuit, the control circuit 10 can make a determination that an authentic cartridge 2 has been inserted in the device 4, such that its projections 38 have pushed the conductor 56 of the movable plate 50 into contact with the terminals 58.

Means (not illustrated) may be provided to guide the movable plate 50 such that it remains parallel. However, it is preferred that the movable plate 50 should be able to tilt if the applied pressure is not evenly distributed across the pressure-responsive surface 20. This reduces the opportunity for the manufacturer of an inauthentic cartridge to circumvent the verification process by providing its cartridge 2 with only a limited set of the projections 38 that do not closely reproduce the protected pattern that is exclusive to the manufacturer of authentic cartridges. The terminals 58 of the test circuit do not necessarily have to be on opposite sides of the cavity 54, as shown, but are preferably disposed on opposite sides of the axis about which the plate 50 is expected to tilt. If the plate 50 is capable of tilting about more than one axis, a second pair of terminals 58 could be provided on opposite sides of the second axis. The movable plate 50 would then comprise first and second conductors 56, each configured to connect between two of the terminals 58 (not necessarily an opposite pair). Each pair of terminals could be part of a separate test circuit but, more efficiently, a single test circuit could be arranged so that its conductive path crosses the plate 50 twice, via both of the conductors 56.

Figure 7 schematically shows a further embodiment of the invention, which is generally similar to Figure 6, with the movable plate 50 being mounted in the same way to move in response to pressure applied to the pressure-responsive surface when the projections 38 of an authentic cartridge 2 are inserted into the recesses 40 of the device 40. This embodiment differs in its electrical connections, whereby the conductor 56 on the movable plate 50 is capable of forming an electrical coupling between two terminals 60 of the circuit that supplies power from the battery 8 in the device 4 to the heater 22 in the cartridge 2. Thus, if the inserted cartridge 2 is not authentic, the power circuit will not be completed and the heater 22 in the cartridge 2 cannot be operated. This embodiment does not comprise any distinct test circuit. However, before the control circuit 10 of the device 4 attempts to supply power sufficient to operate the heater 22, it may first apply a low voltage to the power circuit to test whether current is able to flow so that it can make a preliminary determination of whether an authentic cartridge is attached.

Alternative means could be provided, by which the control circuit 10 could detect the movement of the plate 50 under pressure exerted by the projections 38. For example, a capacitive sensor or a mechanical or magnetic switch.

Although all the illustrated embodiments of the invention show an aerosol generator 22 - specifically, a heater - that forms part of the disposable cartridge 2, that is not essential to the invention. It may not be desirable to dispose of the aerosol generator 22 each time a cartridge 2 is replaced, especially if the generator 22 is based on more complex technology such as a j et head. Therefore, the aerosol generator 22 may instead form part of the reusable device 4, with the cartridge 2 serving only as a source of the aerosol generating material. It remains possible for a power circuit supplying such a generator 22 to pass through a conductive path that is completed only when the projections 38 of the cartridge 2 exert pressure on the pressure-responsive surface 20 in the device 4. Alternatively, the control circuit 10 may be configured to supply power to such an aerosol generator 22 only if it determines that a test circuit has been correctly established, as described in relation to Figure 7 or if it receives the required signal from one or more pressure sensors, as described in relation to Figures 2 to 5.

Claims

1. An aerosol generating system comprising: a cartridge (2) that contains a supply of aerosol generating material (15); and an aerosol generating device (4) for receiving the cartridge (2); wherein: the cartridge (2) comprises one or more projections (38); the aerosol generating device (4) comprises one or more recesses (40) configured to receive the one or more projections (38) when the cartridge (2) is received in the aerosol generating device (4); and the aerosol generating device (4) further comprises a pressure-responsive surface (20) disposed in the base of a first set of one or more of the recesses (40) for detecting pressure exerted by one or more of the projections (38) when received in the first set of recesses (40), wherein the pressure-responsive surface (20) is a surface of a plate that is configured to move in response to pressure applied to the pressure- responsive surface (20) and thereby to complete an electrical circuit.

2. An aerosol generating system according to claim 1 , wherein the plate is mounted such that pressure applied unevenly to the pressure-responsive surface (20) may cause the plate to tilt and thereby fail to complete the electrical circuit.

3. An aerosol generating system according to claim 1 or claim 2, wherein: the cartridge (2) comprises an electrically powered aerosol generator (22); the aerosol generating device (4) comprises a source of electrical power (8); and the electrical circuit is configured, when complete, to supply current from the power source (8) to the aerosol generator (22).

4. An aerosol generating system according to claim 1 or claim 2, wherein: the aerosol generating device (4) comprises a source of electrical power (8) and a controller (10); and the controller (10) is configured to supply current from the power source (8) to the electrical circuit to verify that the cartridge (2) is received correctly in the aerosol generating device (4).

5. An aerosol generating system according to any of claims 1 to 4, wherein the first set of recesses (40) comprises all the recesses (40).

6. An aerosol generating system according to any of claims 1 to 4, comprising a second pressure-responsive surface (21) disposed at the base of a second set of one or more of the recesses (40) for detecting pressure exerted by one or more of the projections (38) when received in the second set of recesses (40), the second set of recesses (40) being distinct from the first set of recesses (40).

7. An aerosol generating system according to any preceding claim, wherein the projections (38) are in the shapes of letters, symbols or other patterns capable of conveying visual information.

8. A method of activating an aerosol generating system that comprises: a cartridge (2), which contains a supply of aerosol generating material (15) and comprises one or more projections (38); and an aerosol generating device (4) for receiving the cartridge (2), the aerosol generating device (4) comprising one or more recesses (40) and a pressure-responsive surface (20) disposed in the base of a first set of one or more of the recesses (40), wherein the pressure-responsive surface (20) is a surface of a plate that is configured to move in response to pressure applied to the pressure-responsive surface (20) and thereby to complete an electrical circuit; the method comprising: inserting the cartridge (2) into the aerosol generating device (4) such that one or more of the projections (38) are received in the first set of recesses (40); and activating the aerosol generating system when the pressure-responsive surface (20) detects pressure exerted by the projections (38) received in the first set of recesses (40).

9. A method according to claim 8, wherein the step of activating the aerosol generating system is carried out in response to completion of the electrical circuit.