Aerosol-generating device for heating an aerosol-forming substrate - Patent Application 20070122997

Abstract

The present disclosure relates to an aerosol generating device comprising a device housing having a cavity for removably receiving at least a portion of an aerosol-generating article, the aerosol-forming substrate including an inductively heated susceptor for heating the aerosol-forming substrate. The device further comprises an induction heating arrangement configured to generate an alternating magnetic field within the cavity when the article is received in the cavity for inductively heating the susceptor of the article. Additionally, the device comprises a closure detector disposed and configured to detect at least one of when a closure of the device is in an open position covering an insertion opening of the cavity, or when the closure moves from a closed position in which the insertion opening is not obstructed by the closure to an open position. The apparatus further comprises a control circuit operatively connected to the induction heating arrangement and the closure detector and configured to: energize the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in an open position or moving from the closed position to the open position, respectively; determine, during energization of the induction heating arrangement, at least one characteristic or a change in at least one characteristic of the induction heating arrangement that depends on at least one of the type, presence, absence, position, and movement of the susceptor within the cavity; and detect at least one particular condition associated with the article based on the determined characteristic or change in the determined characteristic of the induction heating arrangement. The present invention further relates to an aerosol-generating system comprising such an apparatus and an aerosol-generating article.

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating device comprising a cavity for removably receiving at least a portion of an aerosol-generating article, the article including a susceptor and an aerosol-forming substrate that is heated by interaction of the susceptor with an alternating magnetic field generated by the device. The present invention further relates to an aerosol-generating system comprising such a device and an aerosol-generating article. [Background technology]

[0002] Aerosol-generating devices for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated are generally known in the prior art. Such devices may comprise a cavity for removably receiving at least a portion of an aerosol-generating article including the aerosol-forming substrate to be heated. To heat the substrate, the device may further comprise an induction heating arrangement configured to generate an alternating magnetic field within the cavity for inductively heating a susceptor that is part of the article, and to be in thermal proximity or direct physical contact with the substrate to be heated.

[0003] For various purposes, such devices may further comprise means for detecting one or more specific conditions related to the article based on a determined characteristic or change in a determined characteristic of the induction heating arrangement. For example, such means may detect the insertion of an article into the cavity or the type of article inserted into the cavity. Using the heating arrangement to detect such conditions typically requires the heating arrangement to be energized. This is associated with additional power consumption, which in turn may significantly reduce the operating time of the device.

[0004] It would therefore be desirable to have an aerosol generating device that possesses the advantages of prior art solutions while mitigating their limitations. In particular, it would be desirable to have an aerosol generating device that uses a heating arrangement to detect one or more specific conditions associated with an article that is an improvement over prior art solutions. Summary of the Invention

[0005] According to the present invention, there is provided an aerosol generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated. The device comprises a device housing including a cavity for removably receiving at least a portion of an aerosol-generating article, the article including an aerosol-forming substrate and an induction heating susceptor for heating the substrate. The cavity includes an insertion opening for inserting the article into the cavity. The device further comprises a closure reversibly movable relative to the device housing between a closed position in which the closure covers the insertion opening and an open position in which the insertion opening is not obstructed by the closure. The device further comprises an induction heating arrangement configured to generate an alternating magnetic field within the cavity when the article is received in the cavity for inductively heating the susceptor of the article. Additionally, the device comprises a closure detector arranged and configured to detect at least one of when the closure is in an open position or when the closure moves from the closed position to the open position. The device is operably connected to the induction heating arrangement and the closure detector, energizing the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in an open position or moving from a closed position to an open position, respectively; - determining at least one characteristic or a change in at least one characteristic of the induction heating arrangement depending on at least one of the type, presence, absence, position or movement of the susceptor within the cavity during energization of the induction heating arrangement; and - detecting at least one particular condition associated with the article based on the determined characteristic or change in the determined characteristic of the induction heating arrangement.

[0006] Such particular condition may be one of an article type, insertion, presence, absence, position, or displacement of an article within the cavity. Accordingly, the control circuitry may be configured to detect at least one of an article type, insertion, presence, absence, position, and displacement of an article within the cavity based on a determined characteristic or a change in a determined characteristic of the induction heating arrangement.

[0007] According to the present invention, the status detection is based on the fact that a particular article type, insertion, presence, removal, and / or absence of an article affects at least one characteristic of the induction heating arrangement, in particular at least one electrical and / or magnetic characteristic, since the magnetic field-induced interaction between the induction heating arrangement and the susceptor, its effect on the characteristic or change in at least one characteristic, depends on the particular characteristics of the susceptor (susceptor type), the presence or absence of the susceptor in the cavity, and the movement and actual position of the susceptor relative to the induction heating arrangement, in particular relative to the inductor of the induction heating arrangement.

[0008] The at least one characteristic of the induction heating arrangement may be any characteristic having an associated parameter that depends on at least one of the type, presence, absence, position, and movement of a susceptor within the cavity. For example, the at least one characteristic may be a characteristic that has a different value in the presence of a susceptor compared to a value in the absence of a susceptor. For example, the at least one characteristic may be a current, voltage, resistance, frequency, phase shift, magnetic flux, and inductance of the induction heating arrangement.

[0009] Preferably, the at least one property or change in at least one property determined by the control circuit is the current or change in current supplied to the induction heating arrangement.

[0010] Similarly, the at least one characteristic or change in the at least one characteristic may be at least one of the equivalent resistance or inductance of the induction heating arrangement, or a change in the equivalent resistance or a change in the inductance of the induction heating arrangement, respectively. As used herein, the term "equivalent resistance" refers to the real part of the complex impedance defined as the ratio of the AC voltage supplied to the induction heating arrangement to the measured AC current. Thus, the "equivalent resistance" may also be viewed as a resistive load of the induction heating arrangement. Similarly, as used herein, the term "inductance" refers to the imaginary part of the complex impedance defined as the ratio of the AC voltage supplied to the induction heating arrangement to the measured AC current. Inductance generally includes a characteristic of an electrical circuit that is susceptible to external electromagnetic influences.

[0011] A particular value of at least one characteristic or change in at least one characteristic of the induction heating arrangement can be attributed to a particular magnetic permeability and / or electrical resistivity of the susceptor. That is, the susceptor in the aerosol-generating article can include a material having a particular magnetic permeability and / or electrical resistivity. The susceptor preferably includes an electrically conductive material. For example, the susceptor can include a metallic material. The metallic material can be, for example, aluminum, nickel, iron, or one of their alloys, such as carbon steel or ferritic stainless steel. Aluminum has an electrical resistivity of approximately 2.65×10E-08 ohm-meter and a magnetic permeability of approximately 1.256×10E-06 henry / meter, measured at room temperature (20°C). Similarly, ferritic stainless steels have an electrical resistivity of approximately 6.9×10E-07 ohm-meters and a magnetic permeability ranging from 1.26×10E-03 henry / meter to 2.26×10E-03 henry / meter when measured at room temperature (20°C).

[0012] According to the present invention, it has been found that any condition detection involving the heating arrangement consumes the least amount of energy if it is actively energized only when condition detection is actually required. Furthermore, it has been found that many of the above-mentioned conditions are detected immediately before the actual heating operation of the device, i.e., at the beginning of the user experience, when the heating arrangement is not yet operational but is about to be used. Taking this into consideration, it has been concluded that for devices having a movable closure for reversibly covering and uncovering the insertion opening of the cavity, the opening of the closure may be a suitable indicator of the beginning of the user experience and therefore a very suitable trigger for initiating condition detection. Therefore, the present invention proposes initiating condition detection (by energizing the induction heating arrangement) only when the cavity closure is in the open position or when the closure has moved from the closed position to the open position, after which a signal indicating that the closure is in the open position or has moved from the closed position to the open position, respectively, is received.

[0013] Advantageously, using the opening of the closure as a trigger does not require additional user interaction with the device, such as pressing a button, etc. Instead, the trigger advantageously utilizes an action taken by the user at the start of the user experience in any event, i.e., to enable insertion of the aerosol-generating article into the cavity.

[0014] Furthermore, using the induction heating arrangement not only for heating purposes but also for condition detection advantageously also makes it possible to avoid additional assembly space for separate sensor means.

[0015] The opening of the closure may be a highly suitable indicator of the start of a user experience, and the closing of the closure may be a highly suitable indicator of the end of a user experience and therefore a highly suitable trigger for de-energizing the induction heating arrangement. Accordingly, the closure detector may be arranged and configured to further detect at least one of when the closure is in the closed position or when the closure moves from the open position to the closed position. Accordingly, the control circuit may be configured to de-energize the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in the open position or when the closure moves from the closed position to the open position, respectively.

[0016] In particular, the closure detector may be configured to detect both the opening of the closure as well as the closing of the closure. Thus, the closure detector may be configured to detect at least one of when the closure is in the open position or when the closure moves from the closed position to the open position, and when the closure is in the closed position or when the closure moves from the open position to the closed position. More specifically, the closure detector may include a first closure detector configured to detect at least one of when the closure is in the open position or when the closure moves from the closed position to the open position, and a second closure detector configured to detect at least one of when the closure is in the closed position or when the closure moves from the open position to the closed position.

[0017] In general, the closure detector may be any detector capable of reliably detecting the position and / or movement of a closure. For example, the closure detector may include or be one of a magnetic closure detector, an optical closure sensor, a capacitive closure detector, an inductive closure detector, and an electromechanical switch.

[0018] Where the closure detector is or includes a magnetic closure detector, the magnetic closure detector may include at least one magnetic sensor fixedly disposed within the device housing and at least one associated permanent magnet attached to the closure such that the magnetic sensor senses the magnetic field of the associated permanent magnet when the closure is in or moved to the open position, particularly only when the closure is in the open position. In particular, the permanent magnet and magnetic sensor may be arranged such that the magnetic sensor senses the magnetic field of the associated permanent magnet only when the closure is in the open position.

[0019] Alternatively, the magnetic closure detector may include at least one magnetic sensor fixedly disposed within the device housing and at least one associated permanent magnet attached to the closure such that the magnetic sensor senses the magnetic field of the associated permanent magnet when the closure is in or moving to the closed position, particularly only when the closure is in the closed position.

[0020] According to another alternative, the magnetic closure detector may include at least one permanent magnet attached or arranged on / within the closure, and at least two magnetic sensors fixedly arranged within the device housing so that one of the magnetic sensors (in particular, the first magnetic sensor) senses the magnetic field of the permanent magnet when the closure is in the open position or moving to the open position, and the other of the magnetic sensors (in particular, the second magnetic sensor) senses the magnetic field of the permanent magnet when the closure is in the closed position or moving to the closed position, in particular only when the closure is in the closed position.

[0021] According to yet another alternative, the magnetic closure detector may include at least two permanent magnets attached or arranged on / within the closure, and at least two magnetic sensors fixedly arranged within the device housing so that one of the magnetic sensors (particularly the first magnetic sensor) senses the magnetic field of one of the permanent magnets only when the closure is in the open position or moving to the open position, particularly when the closure is in the open position, and so that the other of the magnetic sensors (particularly the second magnetic sensor) senses the magnetic field of the other of the permanent magnets only when the closure is in the closed position or moving to the closed position, particularly when the closure is in the closed position.

[0022] Advantageously, each of the above arrangements ensures that the opening and closing of the closure can be reliably detected, in particular without external interference.

[0023] To ensure interference-free detection of the opening movement or open position of the closure, each magnetic sensor for detecting the opening movement or open position of the closure may be arranged adjacent to the associated permanent magnet at a distance of at most 3 mm, in particular at most 2.5 mm when the closure is in the open position. In addition, each magnetic sensor for detecting the opening movement or open position of the closure may be separated from the associated permanent magnet by at least 5 mm, in particular at least 7.5 mm, preferably at least 10 mm, more preferably at least 15 mm when the closure is in the closed position.

[0024] Similarly, to ensure interference-free detection of the closing movement or closed position of the closure, each magnetic sensor for detecting the closing movement or closed position of the closure may be arranged adjacent to the associated permanent magnet at a distance of at most 3 mm, in particular at most 2.5 mm when the closure is in the open position. In addition, each magnetic sensor for detecting the closing movement or closed position of the closure may be separated from the associated permanent magnet by at least 5 mm, in particular at least 7.5 mm, preferably at least 10 mm, more preferably at least 15 mm when the closure is in the open position.

[0025] The magnetic sensors for the various configurations described above may preferably be Hall sensors.

[0026] If the closure detector is or includes an optical closure detector, the optical closure detector may include a light sensor for detecting light, particularly ambient light. The light sensor is preferably positioned so that it is at least partially covered by the closure or a cover attached / disposed on the closure when the closure is in either the open or closed position, respectively, and is not blocked by the closure or a cover attached / disposed on the closure when the closure is in the closed or open position. In this configuration, the closure or a cover attached / disposed on the closure advantageously functions as a light shutter in front of the light sensor, switching between a light-transmitting state and a light-blocking state depending on the movement of the closure. Thus, the light sensor may generate a first signal indicating that the closure is in the open position when the light sensor detects any light or light above a predetermined intensity threshold, and a second signal indicating that the closure is in the closed position when the light sensor detects no light or only light below a predetermined intensity threshold. The light detected by the light sensor is preferably ambient light. Therefore, no additional light source is required, which keeps the technical effort low.

[0027] Alternatively, the optical closure detector may be configured as a light barrier. To this end, the optical closure detector may include a light emitter and a light receiver for sensing light transmitted from the light emitter. The light emitter and light receiver may be arranged such that light transmitted from the light emitter to the light receiver is blocked by the closure or a cover attached / disposed on the closure when the closure is in the open position and is not blocked by the closure or a cover attached / disposed on the closure when the closure is in the closed position. Similarly, the light emitter and light receiver may be arranged such that light transmitted from the light emitter to the light receiver is blocked by the closure or a cover attached / disposed on the closure when the closure is in the closed position and is not blocked by the closure or a cover attached / disposed on the closure when the closure is in the open position. Advantageously, by using a light barrier with an internal light emitter, occlusion detection is independent of ambient light and therefore works in all lighting conditions, whether outdoors or indoors, and whether day or night.

[0028] If the closure detector is or includes an electromechanical switch, the electromechanical switch may be activated by the closure or by an actuator attached / disposed on the closure when the closure is in the open or closed position, respectively, and may be deactivated by the closure or by an actuator attached / disposed on the closure when the closure is in the closed or open position.

[0029] Alternatively or additionally, the electromechanical switch may be activated by the closure or by an actuator attached / disposed on the closure when the closure moves from the open position to the closed position or from the closed position to the open position. Similarly, the electromechanical switch may be deactivated by the closure or by an actuator attached / disposed on the closure when the closure moves from the closed position to the open position or from the open position to the closed position.

[0030] The closure detector may also include two electromechanical switches, one of which may be activated by the closure portion or by an actuator attached / disposed on the closure portion when the closure portion is in the open position or moves to the open position, and the other of which may be activated by the closure portion or by the same actuator attached / disposed on the closure portion when the closure portion is in the closed position or moves to the closed position.

[0031] In any of these configurations of electromechanical switches, the actuator attached / disposed on the closure may be a mechanical pusher, catch, or the like. Similarly, the closure itself or a portion of the closure may function as a mechanical pusher, catch, or the like. As used herein, the term "electromechanical switch" refers to a mechanically actuated electrical component that can disconnect or connect a conductive path in an electrical circuit, interrupting or diverting current from one conductor to another. In particular, an electromechanical switch may include one or more sets of movable electrical contacts connected to an external circuit. The switch therefore facilitates the generation of at least two signals, one indicating that the switch is activated and the other indicating that the switch is deactivated.

[0032] In general, the closure may be of any type suitable for opening and closing the insertion opening of the cavity.

[0033] According to a first embodiment, the closure may be a sliding closure slidably guided on the device housing between an open position and a closed position. For example, the sliding closure may be slidably guided on the device housing by one or more guide rails, in particular one or more pairs of corresponding guide rails, where one guide rail of the pair of guide rails is arranged on the closure and the other corresponding guide rail of the pair of guide rails is arranged on the device housing. Similarly, the sliding closure may be slidably guided on the device housing by one or more guide grooves and correspondingly formed guide members slidably guided in the guide grooves in a form-fitting manner. For example, the closure may include one or more guide members, each of which is slidably guided in a form-fitting manner in a correspondingly formed guide groove on the device housing. Conversely, one or more guide members may be arranged on the device housing, each of which is slidably guided in a correspondingly formed guide groove on the closure.

[0034] According to a second embodiment, the closure may be a pivoting closure pivotally attached to the device housing, and to this end the aerosol generating device may comprise a pivoting mechanism, such as one or more hinges or one or more pivoting arms, pivotally connecting the closure to the device housing.

[0035] According to a third embodiment, the closure may be an iris diaphragm closure.

[0036] At least one characteristic or a change in at least one characteristic of the induction heating arrangement may be observed by measuring a change in a parameter of the induction heating arrangement. The parameter may be measured directly or indirectly. For example, the presence or absence of an article may be determined by measuring such a parameter and observing that the parameter has a different value in the presence of the article, i.e., in the presence of a susceptor, compared to the value in the absence of the article, i.e., in the absence of a susceptor.

[0037] Preferably, the parameter may be a current. Likewise, the current may be the property itself that is determined by the control circuit. In particular, the at least one property or a change in the at least one property that is determined by the control circuit may be a current or a change in current supplied to the induction heating arrangement. Thus, the control circuit may be configured to detect the presence of a susceptor in the cavity when (or in response to) the current or a change in current supplied to the induction heating arrangement breaches or reaches a threshold value, for example, when the current or a change in current exceeds or falls below a threshold value.

[0038] If the characteristic or characteristic-indicative parameter is current, the control circuit may include a measuring device for measuring a current corresponding to or indicative of at least one characteristic or a change in at least one characteristic of the induction heating arrangement. The characteristic or characteristic-indicative parameter may be a current supplied from a power source of the apparatus, particularly a DC current supplied from a DC power source of the apparatus to the induction heating arrangement. Accordingly, the control circuit may include a current measuring device arranged and configured to measure the current supplied from a power source of the apparatus, particularly a DC current supplied from a DC power source of the apparatus to the induction heating arrangement. The measuring device may include a current measuring device, particularly a DC current measuring device, arranged in series between the power source of the apparatus, particularly a DC power source, and the induction heating arrangement. For example, the measuring device may include a resistor and a shunt amplifier. In use, when an aerosol-generating article is inserted into the cavity of the aerosol-generating device, the susceptor is or becomes present in the cavity, increasing the equivalent resistance due to an increased resistive load. This results in a reduction in the (DC) current supplied to the induction heating arrangement. The reduction in (DC) current is detected by a current measuring device in the control circuit, which can then activate the heating operation of the induction heating arrangement to heat the substrate. Conversely, when an aerosol-generating article is not present in the cavity, the equivalent resistance is lower due to a lower resistive load in the absence of the susceptor. This results in a higher (DC) current supplying the induction heating arrangement, which can be detected by a current measuring device in the control circuit, and therefore indicates the absence of the article from the cavity. Similarly, when the aerosol-generating article is displaced within the cavity, the equivalent resistance may change to a higher or lower value due to a respective change in resistive load related to the actual position of the heating arrangement, particularly the susceptor, relative to the inductor of the heating arrangement. The change in resistive load causes a change in the (DC) current supplying the induction heating arrangement, which, again, can be detected by a current measuring device, and therefore indicates the displacement or specific position of the article within the cavity.

[0039] To further reduce power consumption and thus further increase the overall operating time of the apparatus compared to other solutions, the induction heating arrangement may be operated in a pulsed mode for condition detection purposes. Accordingly, the control circuit may be configured to intermittently generate power pulses, particularly to periodically turn on the induction heating arrangement, and determine at least one characteristic or a change in at least one characteristic of the induction heating arrangement during one or more power pulses. To generate such power pulses, the control circuit may include a switch configured and arranged to control the supply of power from a power source of the apparatus, particularly a DC power source, to the induction heating arrangement. The switch may be intermittently opened and closed to intermittently turn on the induction heating arrangement to enable detection of at least one specific condition related to the article based on the determined characteristic and change in the determined characteristic of the induction heating arrangement.

[0040] Depending on the particular condition detected by the control circuit, the control circuit may be configured to take further action, particularly to initiate, enable, or disable various modes of operation, for example, heating operation.

[0041] Preferably, the control circuit is configured to initiate a heating operation of the induction heating arrangement in response to detecting the insertion of an article into the cavity. Advantageously, this enhances user convenience, as the heating operation begins automatically upon insertion of the article into the cavity, without the need for further user input. In particular, the user experience begins immediately, as is known from conventional cigarettes. Additionally or alternatively, the heating operation of the induction heating arrangement can be initiated manually, i.e., by user input, for example, by pressing a button.

[0042] The control circuit may be further configured to disable heating operation of the induction heating arrangement in response to detecting at least one of the absence of an article from the cavity, displacement of an article within the cavity, or insertion of an improper article type into the cavity. Advantageously, this prevents a user of the device from initiating heating operation without an article present in the cavity, or without an article properly positioned within the cavity, or with an improper article type. As a result, damage and malfunction of the device can be effectively prevented.

[0043] The control circuitry may be further configured to terminate heating operation of the induction heating arrangement under various conditions. In particular, the control circuitry may be configured to terminate heating operation of the device in response to at least one of detecting a predetermined number of puffs, detecting the lapse of a predetermined heating time, or receiving user input.

[0044] The control circuit may also be configured to verify the insertion of an item into or removal of an item from the cavity by energizing the induction heating arrangement, in particular by generating at least one verification power pulse a predetermined period after first detecting a change in at least one characteristic of the induction heating arrangement, and by redetecting the change in at least one characteristic of the induction heating arrangement.

[0045] When the control circuit is configured to energize the induction heating arrangement in a pulsed mode by generating power pulses to intermittently turn on the induction heating arrangement, the control circuit may include a switch constructed and arranged to control the supply of power from a power source of the apparatus, in particular a DC power source, to the induction heating arrangement. To this end, the switch may be intermittently opened and closed to intermittently turn on the induction heating arrangement.

[0046] The generation of power pulses may also be used to achieve pulse heating operation, in which the induction heating arrangement is intermittently turned on and off to heat the susceptor in a pulsed mode. The aforementioned switches in the control circuit may also be used for this purpose. In particular, the heating mode may include pulse width modulation of the heating power pulses to control the heating temperature.

[0047] It is also possible to permanently close the switch and continuously apply DC voltage from the DC power supply to the induction heating arrangement during heating operation of the device, and therefore this mode may be referred to as continuous heating operation.

[0048] During heating operation, the control circuit may also be able to detect the removal of the aerosol-generating article from the cavity by detecting a change in at least one characteristic of the induction heating arrangement due to the susceptor being absent from the cavity when the article is removed from the cavity.

[0049] A power pulse generated to detect at least one particular condition associated with an article may be referred to as a probe power pulse, and the control circuit may be configured to generate the probe power pulse accordingly. Similarly, a power pulse generated to heat a susceptor in a pulse mode may be referred to as a heating power pulse, and the control circuit may be configured to generate the heating power pulse accordingly.

[0050] In general, the probe power pulse and the heating power pulse may be identical. Alternatively, the probe power pulse and the heating power pulse may differ from each other by at least one characteristic of the power pulse, in particular by at least one of the pulse pattern, the amplitude of the power pulse, the pulse duration, and the time interval between two consecutive power pulses. In particular, the amplitude of the heating power pulse may be greater than the amplitude of the probe power pulse. Additionally, the probe power pulse may have a fixed pulse pattern, in particular a fixed periodicity. In contrast, the heating power pulse may have a non-fixed, in particular a variable pulse pattern, for example to realize pulse width modulation of the heating power.

[0051] In general, the pulse duration and time interval between two consecutive power pulses, especially the probe power pulse, should be selected to balance the impact of energy depletion and the performance of the user experience. The pulse duration should be kept as short as possible, but long enough to provide a reliable measurement of at least one characteristic, or a change in at least one characteristic, of the induction heating arrangement. Similarly, the longer the time interval between two consecutive power pulses, especially the probe power pulse, the less energy depletion there will be. However, the time interval between two consecutive power pulses, especially the probe power pulse, should not be too long, otherwise condition detection may take too long.

[0052] Taking these factors into consideration, the power pulse, particularly the probe power pulse, may have a pulse duration within the range of 1 microsecond to 500 microseconds, particularly 10 microseconds to 300 microseconds, preferably 15 microseconds to 120 microseconds, and most preferably 30 microseconds to 10 microseconds. The term "pulse duration" as used herein refers to the time interval during which power is supplied to the heating arrangement, particularly during which the aforementioned switch is closed. The time interval between two consecutive power pulses, particularly the probe power pulses, may be within the range of 50 milliseconds to 2 seconds, particularly 100 milliseconds to 2 seconds, and preferably 500 milliseconds to 1 second. The sum of the pulse duration and the time interval between two consecutive power pulses may be expressed as the polling time, i.e., the difference in time between the start of one pulse and the start of the next pulse. The polling time may be within the range of 50 milliseconds to 2.5 seconds, particularly 51 milliseconds to 2.5 milliseconds, more particularly 100 milliseconds to 2 seconds, and preferably 500 milliseconds to 1 second.

[0053] The power pulses used for condition detection, particularly probe power pulses, are preferably generated for a predetermined period of time. That is, condition detection may last for a finite, predetermined period of time. In the event of a particular condition, for example, if insertion of an item into the cavity is not detected within the predetermined period of time, condition detection may be stopped, i.e., power pulse generation may be turned off to conserve power, as described above. Similarly, if a particular condition is detected within the predetermined period of time, condition detection, and therefore power pulse generation, may be stopped, particularly immediately, in response to the detection of the particular condition.

[0054] The induction heating arrangement may be configured to generate a high frequency alternating magnetic field, which as referred to herein may be in the range of 500 kHz (kilohertz) to 30 MHz (megahertz), particularly 5 MHz (megahertz) to 15 MHz (megahertz), preferably 5 MHz (megahertz) to 10 MHz (megahertz).

[0055] To generate the alternating magnetic field, the induction heating arrangement may include a DC / AC converter connected to the DC power source. The DC / AC converter may include an LC network. For example, the DC / AC converter may include a class C power amplifier, a class D power amplifier, or a class E power amplifier. In particular, the DC / AC converter may include a transistor switch, a transistor switch driver circuit, and an LC network. The LC network may include a series connection of a capacitor and an inductor, the inductor configured and arranged to generate an alternating magnetic field in the cavity, particularly for inductive heating of the susceptor and for article detection. The LC network may further include a shunt capacitor in parallel with the transistor switch. In addition, the DC / AC converter may include a choke inductor for supplying a DC supply voltage +V_DC to the DC power source.

[0056] The inductor for generating the alternating magnetic field in the cavity may include at least one induction coil, particularly a single induction coil, or multiple induction coils. The number of induction coils may depend on the size and / or number of susceptors. The induction coil or multiple induction coils may have a shape that matches the shape of one or more susceptors in the aerosol-generating article. Similarly, the single or multiple induction coils may have a shape that matches the shape of the housing of the aerosol-generating device. The at least one induction coil may be a spiral coil or a flat planar coil, particularly a pancake coil or a curved planar coil. The at least one induction coil may be wound around a preferably cylindrical coil support, such as a ferrite core.

[0057] The control circuitry may further be configured to control the overall operation of the aerosol generating device, and the control circuitry and at least part of the induction heating arrangement may be integral parts of the overall electrical circuitry of the aerosol generating device.

[0058] The control circuitry may include a microprocessor, such as a programmable microprocessor, microcontroller, or application specific integrated circuit chip (ASIC) or other electronic circuitry capable of providing control. The microprocessor may be configured to at least one of control switches used to generate power pulses to intermittently turn on the induction heating arrangement, read measurement devices to measure current supplied from the power source to the induction heating arrangement (if present), and control transistor switch driver circuits of the induction heating arrangement (if present).

[0059] The control circuit may be the overall controller of the aerosol generating device or may be part of the overall controller of the aerosol generating device. The controller and at least part of the induction source, particularly the induction source apart from the inductor, may be arranged on a common printed circuit board. This is particularly advantageous with regard to a compact design of the heating arrangement.

[0060] The aerosol generating device is preferably a smoke suction device for generating an aerosol that can be directly inhaled by a user through the user's mouth. Specifically, the aerosol generating device is a handheld aerosol generating device.

[0061] As mentioned above, the aerosol generating device preferably includes a power source, particularly a DC power source such as a battery. The power source may require recharging, i.e., the power source may be rechargeable. The power source may have a capacity that allows for storage of energy sufficient for one or more user experiences. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, or a multiple of six minutes. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffs, or for discontinuous activation of the induction source.

[0062] As used herein, the direction in which the aerosol-generating article is inserted into the cavity is referred to as the insertion direction. The insertion direction preferably corresponds to an extension of the length axis, particularly the central axis, of the cavity. After insertion into the cavity, at least a portion of the aerosol-generating article may still extend outward through the insertion opening. The outwardly extending portion is preferably provided for interaction with a user, particularly for entry into the user's mouth. Thus, during use of the device, the insertion opening may be close to the user's mouth. Consequently, as used herein, the section closest to the insertion opening or the section closest to the user's mouth during use of the device is denoted with the prefix "proximal." A section disposed further away is denoted with the prefix "distal." In accordance with this convention, the cavity may be disposed or located in the proximal portion of the aerosol-generating device. The insertion opening may be disposed or located at the proximal end of the aerosol-generating device, particularly at the proximal end of the cavity. The cavity may include a bottom at the distal end, opposite the insertion opening.

[0063] The aerosol-generating device may have an air path extending from at least one air inlet into the cavity. That is, the aerosol-generating device may have at least one air inlet in fluid communication with the cavity. When an aerosol-generating article is inserted into the cavity, the air path may further extend through an aerosol-forming substrate within the article and a mouthpiece of the article into the user's mouth. Preferably, the air inlet is realized at an insertion opening of the cavity used to insert the article into the cavity. Thus, when the article is received in the cavity, air can be drawn into the cavity at the rim of the insertion opening and further through an airflow passage formed between the outer periphery of the aerosol-generating article and at least one portion of the inner surface of the cavity.

[0064] In general, the cavity may have any suitable shape. In particular, the shape of the cavity may correspond to the shape of the aerosol-generating article to be received therein. Preferably, the cavity may have a substantially cylindrical or tapered shape, for example, a substantially conical or substantially frusto-conical shape. The cavity may have any suitable cross-section as viewed in a plane perpendicular to the longitudinal axis of the cavity or perpendicular to the direction of insertion of the article. Specifically, the cross-section of the cavity may correspond to the shape of the aerosol-generating article to be received therein. Preferably, the cavity has a substantially circular cross-section. Alternatively, the cavity may have a substantially elliptical cross-section, a substantially oval cross-section, a substantially square cross-section, a substantially rectangular cross-section, a substantially triangular cross-section, or a substantially polygonal cross-section. As used herein, the above-mentioned shapes and cross-sections preferably refer to the shape or cross-section of the cavity without taking into account any protrusions on the inner surface of the cavity.

[0065] The inductor may be disposed so as to surround at least a portion of the cavity or at least a portion of the inner surface of the cavity, respectively. The inductor may be, for example, a helical coil disposed within a sidewall of the cavity. In particular, the inductor may be integrated into a wall defining the cavity. For example, the inductor may be integrated into a sidewall of the cavity so as to surround at least a portion of the interior of the cavity.

[0066] The cavity may include a plurality of protrusions extending into the interior of the cavity. Preferably, the protrusions are separated from one another so that an airflow passage is formed between adjacent protrusions, i.e., by a gap (free space) between adjacent protrusions. In addition, the plurality of protrusions may be configured to contact at least a portion of the aerosol-generating article to retain the aerosol-generating article within the cavity. The plurality of protrusions may include or be formed as ribs. Preferably, the one or more ribs extend along the length axis, particularly along the central axis of the cavity.

[0067] The present invention further relates to an aerosol generation system comprising an aerosol generating device according to any one of the preceding claims and an aerosol-generating article for use in the aerosol generating device, the aerosol-generating article being removably receivable within a cavity of the device and including at least one aerosol-forming substrate and at least one inductively heated susceptor for heating the substrate by interaction of the susceptor with an alternating magnetic field provided by an inductive heating arrangement of the device.

[0068] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate that, when heated, releases a volatile compound capable of forming an aerosol. Accordingly, an aerosol-generating article may be referred to as a heated aerosol-generating article or a heating aerosol-generating article. That is, an aerosol-generating article preferably comprises at least one aerosol-forming substrate that is intended to be heated, rather than combusted, to release a volatile compound capable of forming an aerosol. An aerosol-generating article may also be a consumable product, particularly one that is discarded after a single use.

[0069] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds capable of forming an aerosol when heated. The aerosol-forming substrate may be a solid aerosol-forming substrate, a gel-like aerosol-forming substrate, or a liquid aerosol-forming substrate, or a combination thereof. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. Alternatively, or additionally, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol. The aerosol-forming substrate may also contain other additives and ingredients, such as nicotine or flavoring substances. In particular, the liquid aerosol-forming substrate may comprise water, a solvent, ethanol, a plant extract, and a natural or artificial flavor. The aerosol-forming substrate may also be a paste-like material, a sachet of porous material containing the aerosol-forming substrate, or, for example, loose tobacco mixed with a gelling or adhesive agent, which may include a common aerosol former such as glycerin, and then compressed or shaped into a plug.

[0070] The aerosol-generating article may be a tobacco article. In particular, the article may be a rod-shaped article, preferably a cylindrical rod-shaped article which may resemble a conventional cigarette. The aerosol-generating article may have a circular, elliptical, oval, square, rectangular, triangular or polygonal cross-section.

[0071] In one embodiment, the aerosol-generating article may be a rod-shaped article, specifically a cylindrical article comprising one or more of a distal forward plug element, a base element, a first tube element, a second tube element, and a filter element.

[0072] The substrate element preferably comprises at least one aerosol-forming substrate to be heated and a susceptor in thermal contact with or in thermal proximity to the aerosol-forming substrate. The substrate element may have a length of 10 mm to 14 mm, for example 12 mm.

[0073] As used herein, the term "susceptor" refers to an element comprising a material capable of being inductively heated in an alternating magnetic field, which may be the result of at least one of hysteresis losses or eddy currents induced within the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0074] The first tube element is distal to the second tube element. Preferably, the first tube element is proximal to the base element, and the second tube element is proximal to the first tube element and distal to the filter element, i.e., between the first tube element and the filter element. At least one of the first tube element and the second tube element may comprise a central air passage. The cross-section of the central air passage of the second tube element may be larger than the cross-section of the central air passage of the first tube element. Preferably, at least one of the first tube element and the second tube element may comprise a hollow cellulose acetate tube. At least one of the first tube element and the second tube element may have a length of 6 to 10 millimeters, for example 8 millimeters.

[0075] The filter element preferably functions as a mouthpiece or is part of a mouthpiece together with a second tube element. As used herein, the term "mouthpiece" refers to the portion of the article through which the aerosol exits the aerosol-generating article. The filter element may have a length of 10 to 14 millimeters, for example 12 millimeters.

[0076] The distal front plug element may be used to cover and protect the distal front end of the base element. The distal front plug element may have a length of 3 to 6 millimeters, for example 5 millimeters. The distal front plug element may be made of the same material as the filter element.

[0077] All of the aforementioned elements may be disposed consecutively along the longitudinal axis of the article in the order described above, with the distal front plug element preferably disposed at the distal end of the article and the filter element preferably disposed at the proximal end of the article. Each of the aforementioned elements may be substantially cylindrical. Specifically, all of the elements may have the same external cross-sectional shape and / or dimensions.

[0078] Additionally, the elements may be surrounded by one or more outer wrappers to hold the elements together, maintain the desired cross-sectional shape of the rod-shaped article, etc. The wrappers are preferably made of paper. The wrappers may further comprise an adhesive that bonds the overlapping free ends of the wrappers to one another. For example, the distal forward plug element, the base element, and the first tubing element may be surrounded by a first wrapper, and the second tubing element and the filter element may be surrounded by a second wrapper. The second wrapper may also surround at least a portion of the first tubing element (after being wrapped by the first wrapper) to connect the distal forward plug element, the base element, and the first tubing element surrounded by the first wrapper to the second tubing element and the filter element. The second wrapper may comprise perforations around its circumference.

[0079] Further features and advantages of the aerosol generating system and aerosol generating article according to the invention have already been described above in relation to the aerosol generating device of the invention and apply equally. [Example]

[0080] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0081] Example 1 1. An aerosol generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated, the device comprising: a device housing including a cavity for removably receiving at least a portion of an aerosol-generating article, the article including an aerosol-forming substrate and an induction-heated susceptor for heating the substrate, the cavity including an insertion opening for inserting the article into the cavity; and a closure part reversibly movable relative to the device housing between a closed position in which the closure part covers the insertion opening and an open position in which the insertion opening is not obstructed by the closure part; an induction heating arrangement configured to generate an alternating magnetic field within the cavity for inductively heating a susceptor of an article when the article is received within the cavity; a closure detector arranged and configured to detect at least one of when the closure is in an open position or when the closure moves from a closed position to an open position; operatively connected to the induction heating arrangement and the closure detector; energizing the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in an open position or moving from a closed position to an open position, respectively; - determining at least one characteristic or a change in at least one characteristic of the induction heating arrangement depending on at least one of the type, presence, absence, position, and movement of the susceptor within the cavity during energization of the induction heating arrangement; - detecting at least one particular condition associated with the item based on a determined characteristic or a change in a determined characteristic of the induction heating arrangement. Example 2 An aerosol generating device as described in Example 1, wherein the control circuit is configured to detect at least one of the item type, insertion, presence, absence, position, and displacement of an item within the cavity based on a determined characteristic or a change in a determined characteristic of the induction heating arrangement. Example 3 An aerosol generating device as described in any one of the preceding embodiments, wherein the control circuit is configured to generate power pulses to intermittently turn on the induction heating arrangement and determine at least one characteristic or change in at least one characteristic of the induction heating arrangement during one or more power pulses. Example 4 An aerosol generating device as described in any one of the preceding embodiments, wherein the closure detector is arranged and configured to further detect at least one of when the closure is in a closed position or when the closure moves from an open position to a closed position. Example 5 An aerosol generating device as described in Example 4, wherein the control circuit is configured to stop energizing the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in a closed position or when the closure moves from an open position to a closed position, respectively. Example 6 10. The aerosol generating device of any one of the preceding embodiments, wherein the occlusion detector comprises one of a magnetic occlusion detector, an optical occlusion sensor, a capacitive occlusion detector, an inductive occlusion detector, and an electromechanical switch. Example 7 An aerosol generating device as described in Example 6, wherein the magnetic closure detector includes at least one magnetic sensor fixedly arranged within the device housing to detect when the closure is in an open position or when the closure moves from a closed position to an open position, and at least one associated permanent magnet attached to the closure so that the magnetic sensor senses the magnetic field of the associated permanent magnet only when the closure is in an open position or moves to an open position, particularly when the closure is in the open position. Example 8 An aerosol generating device as described in Example 7, wherein at least one magnetic sensor is arranged adjacent to at least one associated permanent magnet at a distance of up to 3 millimeters, particularly up to 2.5 millimeters, when the closure is in the open position. Example 9 An aerosol generating device described in either Example 7 or Example 8, wherein at least one magnetic sensor is separated from its associated permanent magnet by at least 5 millimeters, in particular at least 7.5 millimeters, preferably at least 10 millimeters, and more preferably at least 15 millimeters when the closure is in the closed position. Example 10 An aerosol generating device as described in Example 6, wherein the optical closure detector includes an optical sensor for detecting light, particularly ambient light, and the optical sensor is arranged so that it is at least partially covered by the closure or by a cover attached or disposed on the closure when the closure is in the open position or the closed position, respectively, and is not obstructed by the closure or by a cover attached or disposed on the closure when the closure is in the closed position or the open position. Example 11 An aerosol generating device as described in Example 6, wherein the optical closure detector includes a light emitter and a light receiver for sensing light transmitted from the light emitter, and the light emitter and light receiver are blocked by the closure or by a cover attached or disposed on the closure when the closure is in an open position or a closed position, respectively, and are not blocked by the closure or by a cover attached to the closure when the closure is in a closed position or an open position. Example 12 An aerosol generating device as described in Example 6, wherein the electromechanical switch is activated by the closure or by an actuator attached or disposed on the closure when the closure is in the open position or the closed position, respectively, and is stopped by the closure or by an actuator attached to the closure when the closure is in the closed position or the open position. Example 13 An aerosol generating device as described in Example 6, wherein the electromechanical switch is activated by the closure or by an actuator attached to or disposed on the closure when the closure moves from an open position to a closed position or when the closure moves from a closed position to an open position. Example 14 An aerosol generating device as described in Example 13, wherein the electromechanical switch is stopped by the closure portion or by an actuator attached to or disposed on the closure portion when the closure portion moves from a closed position to an open position or when the closure portion moves from an open position to a closed position. Example 15 15. An aerosol generating device according to any one of Examples 1 to 14, wherein the closure is a sliding closure that is slidably guided on the device housing between an open position and a closed position. Example 16 15. An aerosol generating device according to any one of Examples 1 to 14, wherein the closure is a pivoting closure pivotally attached to the device housing. Example 17 15. An aerosol generating device according to any one of Examples 1 to 14, wherein the closure is an iris diaphragm closure. Example 18 10. An aerosol generating device according to any one of the preceding embodiments, wherein the at least one characteristic or change in the at least one characteristic determined by the control circuit is a current or a change in current supplied to the induction heating arrangement. Example 19 An aerosol generating device according to any one of the preceding embodiments, wherein the control circuit includes a measuring device for measuring a current corresponding to or indicative of at least one characteristic or a change in at least one characteristic of the induction heating arrangement. Example 20 An aerosol generating device described in either Example 18 or Example 19, wherein the control circuit is configured to detect the presence of a susceptor in the cavity when (or in response to) the current or change in current supplied to the induction heating arrangement exceeds or reaches a threshold, for example, when the current or change in current exceeds or falls below the threshold. Example 21 10. An aerosol generating device according to any one of the preceding embodiments, wherein the control circuit is configured to initiate heating operation of the induction heating arrangement in response to detecting insertion of an item into the cavity. Example 22 An aerosol generating device according to any one of the preceding embodiments, wherein the control circuit is configured to disable heating operation of the induction heating arrangement in response to detecting removal of the article from the cavity. Example 23 An aerosol generation system comprising an aerosol generating device according to any one of the preceding embodiments and an aerosol-generating article for use in the aerosol generating device, the aerosol-generating article being removably receivable within a cavity of the device and including at least one aerosol-forming substrate, and at least one inductively heated susceptor for heating the substrate by interaction of the susceptor with an alternating magnetic field provided by an inductive heating arrangement of the device.

[0082] The invention will now be described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0083] [Figure 1] FIG. 1 shows a schematic diagram of an exemplary embodiment of an aerosol generation system according to the present invention, including an aerosol generating device and an aerosol-generating article for use in the device. [Figure 2] FIG. 2 shows a schematic diagram of an exemplary embodiment of an aerosol generation system according to the present invention, including an aerosol generating device and an aerosol-generating article for use in the device. [Figure 3a] FIG. 3a shows the aerosol generating device of the system according to FIGS. 1 and 2 with the cavity closure in the closed position. [Figure 3b] FIG. 3b shows the aerosol generating device of the system according to FIGS. 1 and 2 with the cavity closure in the closed position. [Figure 4a] FIG. 4a shows the aerosol generating device of the system according to FIGS. 1 and 2 with the cavity closure in the open position. [Figure 4b] FIG. 4b shows the aerosol generating device of the system according to FIGS. 1 and 2 with the cavity closure in the open position. [Figure 5] FIG. 5 shows a schematic illustration of an induction heating arrangement for an aerosol generating device according to FIGS. [Figure 6] FIG. 6 shows details of the pulsed operation of the induction heating arrangement shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0084] 1 and 2 show schematically an exemplary embodiment of an aerosol-generating system 1 according to the present invention configured to generate an inhalable aerosol by heating an aerosol-forming substrate 21. The system 1 comprises an aerosol-generating article 10 including the substrate 21 to be heated, and an elongated aerosol-generating device 100 for heating the substrate 21 upon engagement of the article 10 with the device 100.

[0085] As can be particularly seen in Figure 1, the aerosol-generating article 10 has a substantially rod-shaped configuration similar to that of a conventional cigarette. In this embodiment, the article 10 comprises five elements arranged consecutively in coaxial alignment: a distal front plug element 40, a base element 20, a first tube element 50, a second tube element 55, and a filter element 60 disposed as a mouthpiece at the proximal end of the article 10. The base element 20 includes an aerosol-forming substrate 21 to be heated and an induction heating susceptor 30 in direct physical contact with the substrate 21 for heating the substrate 21 through interaction of the induction heating susceptor 30 with the alternating magnetic field provided by the apparatus 100. The induction heating process is described in more detail below. All of the aforementioned elements 20, 40, 50, 55, and 60 have a substantially cylindrical shape with substantially the same diameter. 1 and 2, the five elements 20, 40, 50, 55 and 60 are surrounded by an outer wrapper 70 to hold the elements together and maintain the desired circular cross-sectional shape of the rod-like article 10. The wrapper 70 is preferably made of paper.

[0086] The aerosol-generating device 100 comprises a device housing 101 including a cavity 103 in a proximal portion 102 of the device 100 configured to removably receive at least a portion of an aerosol-generating article 10. For inserting the article 10 into the cavity 103, the device 100 comprises an insertion opening 105 in a proximal end face of the device housing 101.

[0087] As shown in Figures 1 and 2, 3a, 3b, and 4a and 4b, the aerosol generating device of this embodiment includes a closure 107 that is reversibly movable relative to the device housing 101 between a closed position in which the closure 107 covers the insertion opening 105 (see Figures 3a and 3b) and an open position in which the insertion opening 105 is not obstructed by the closure 107 (see Figures 4a and 4b, and Figures 1 and 2). Advantageously, the closure 107 tightly closes the cavity 103, thus preventing debris from unintentionally entering the cavity when no article 10 is present in the cavity 103, particularly when the device 100 is not in use. In this embodiment, the closure 107 is a sliding closure that is slidably guided on the device housing 101. To this end, the closure may include one or more guide members (not shown), each of which is slidably guided in a form-fitting manner in a correspondingly formed guide groove 106 on the device housing 101.

[0088] Within device housing 101, device 100 includes a DC power supply 150 and a controller 160 for powering and controlling the operation of device 100.

[0089] To heat the substrate 21 within the article 10, the apparatus 100 includes an induction heating arrangement 110 including an induction coil 118 for generating a high-frequency alternating magnetic field within the cavity 103. In this embodiment, the induction coil 118 is a helical coil disposed within the proximal portion 102 of the apparatus so as to circumferentially surround the cylindrical cavity 103. The coil 118 is disposed such that the susceptor 30 of the aerosol-generating article 10 experiences the magnetic field as the article 10 is engaged with the apparatus 100. As described above, the alternating magnetic field is used to inductively heat the susceptor 30 within the aerosol-generating article 10 when the aerosol-generating article 10 is received within the cavity 103 (see FIG. 2 ). Therefore, the alternating magnetic field may induce at least one of eddy currents and hysteresis losses within the susceptor 30, depending on the magnetic and electrical properties of the particular susceptor material. As a result, the susceptor 30 is heated to a temperature sufficient to vaporize the aerosol-forming substrate 21 surrounding the susceptor 30 within the article 10 .

[0090] The system is configured so that upon insertion of the article 10 into the cavity 103 and activation of the heating arrangement 110, a user can puff on the filter element 60, thereby drawing air into the cavity 103 at the rim of the insertion opening 105. The airflow extends further toward the distal end of the cavity 103 along a passage formed between the inner surface of the cylindrical cavity 103 and the outer surface of the cylindrical article 10. At the distal end of the cavity 103, the airflow enters the aerosol-generating article 10 through the distal front plug element 40 and further passes through the base element 20, the first and second tube elements 50 and 55, and the filter element 60, before finally exiting the article 10 and entering the user's mouth. Thus, material vaporized from the aerosol-forming substrate 21 during operation of the device can be entrained in the airflow through the base element 20. Thereafter, as it passes through the first tube element 50, the second tube element 55, and the filter element 60, the airflow containing the vaporized material is cooled to form an aerosol that exits the article 10 through the filter element 60.

[0091] FIG. 5 shows further details of the induction heating arrangement 110. According to this embodiment, the induction heating arrangement 110 comprises a DC / AC inverter connected to the DC power supply 150 shown in FIGS. 1 and 2. The DC / AC inverter includes a class-E power amplifier including the following components: a transistor switch 111 including a field-effect transistor (FET), e.g., a metal-oxide semiconductor field-effect transistor (MOSFET), a transistor switch supply circuit indicated by arrow 112 for supplying a switching signal (gate-source voltage) to the transistor switch 111, and an LC load network 113 including a shunt capacitor C1 and a series connection of a capacitor C2 and an inductor L2. Inductor L2 corresponds to induction coil 118 shown in FIGS. 1 and 2 for generating an alternating magnetic field in cavity 103. Additionally, a choke L1 is provided for supplying a DC supply voltage +V_DC to the DC power supply 150. 5, the ohmic resistance R representing the total equivalent resistance or total resistive load 114 when the system is in use, i.e. when an item is inserted into the cavity 103 of the apparatus 100, is the sum of the ohmic resistance of the inductor coil 118 marked L2 and the ohmic resistance of the susceptor. Otherwise, when no item is inserted into the cavity 103, the equivalent resistance or resistive load 114 corresponds only to the ohmic resistance of the inductor coil 118. Further details of the induction heating arrangement 110 according to this embodiment, in particular with regard to its operating principle, are disclosed, for example, in WO 2015 / 177046 A1.

[0092] For various purposes, it may be desirable to detect certain conditions related to the aerosol-generating articles received in the cavity 103, particularly to automatically initiate or disable the heating process. Such conditions may be, for example, the type of article, insertion, presence, absence, position, or displacement of the article in the cavity 103. According to the present invention, this type of condition detection is achieved via the heating arrangement 110, which advantageously makes it possible to avoid additional assembly space for a separate sensor means. The basic concept for detecting one or more of these conditions is to detect at least one characteristic or a change in at least one characteristic of the induction heating arrangement 110 that depends on at least one of the type, presence, absence, position, and movement of the susceptor 30 of the article 10 in the cavity 103. In this embodiment, it is the total resistive load 114 of the heating arrangement 110 that is used as a characteristic of the induction heating arrangement that indicates, among other things, the presence or absence of the article 10 in the cavity 103. As explained above, the value of the total equivalent resistance or total resistive load 114 depends on the presence or absence of the susceptor 30 near the induction coil 118. When an article is inserted into the cavity 103 of the apparatus 100, the total equivalent resistance 118 corresponds to the sum of the ohmic resistance of the inductor coil 118 and the ohmic resistance of the susceptor 30, and when no article is received in the cavity 103, the total equivalent resistance 118 corresponds to the ohmic resistance of the inductor coil 118.

[0093] This change in equivalent resistance 118 can be detected via the DC current I_DC provided from the DC power supply 150 to the induction heating arrangement 110, i.e., the LC load network 113. To this end, the aerosol-generating apparatus includes a current measuring device 140 arranged in series between the DC power supply 150 and the LC load network 113 (see FIG. 5 ). Thus, when the aerosol-generating article 10 is inserted into the cavity 103 of the apparatus 100, the presence of the susceptor 30 increases the equivalent resistance 118 of the heating arrangement due to the high resistive load 114 in the presence of the susceptor 30. This results in a reduction in the DC current supplied to the induction heating arrangement 110. The reduction in DC current I_DC is detected by the current measuring device 140, which can then be used as a trigger signal to initiate a heating operation to heat the substrate 21. Conversely, when the aerosol-generating article 10 is removed from the cavity 103, the absence of the susceptor 30 is associated with a lower value of the equivalent resistance 118 of the heating arrangement 110 due to the lower resistive load 114 in the absence of the susceptor 30. This results in a lower value of the DC current supplied to the induction heating arrangement 110. The decrease and increase in DC current, or the respective high or low values ​​ΔI_DC, I_NA, I_A, may be detectable by the current measuring device 140 (see FIG. 6).

[0094] When the aerosol generating device 100 is in the status detection mode, the heating assembly is preferably operated in a pulsed mode rather than a continuous mode to reduce overall power consumption. To this end, the device 100 according to this embodiment includes a switch 130 arranged and configured to control the power supply from the DC power source 150 to the induction heating arrangement 110. As shown in FIG. 5 , the switch 130 is arranged in series between the DC power source 150 and the LC load network 113. During the status detection, the switch 130 is intermittently opened and closed to generate power pulses for intermittently turning on the induction heating arrangement 110. During the subsequent heating operation, the switch 130 may be permanently closed to continuously apply a DC voltage from the DC power source to the induction heating arrangement 110 to continuously heat the susceptor 30. Alternatively, the switch 130 may be intermittently opened and closed during the heating operation to generate heating power pulses, for example, for pulsed heating of the susceptor 30.

[0095] As further shown in FIG. 3 , both switch 130 and current measuring device 140 are part of a control circuit that also includes microprocessor 160. Microprocessor 160 is configured to control switch 130, for example, to read measuring device 140 to measure the current I_DC supplied from the DC power supply to induction heating arrangement 110, as well as to control transistor switch driver circuit 112 to generate a power pulse. The control circuit may be part of or may be the overall controller of aerosol generation device 100. During condition detection, microprocessor 160 initiates activation of switch 130 by closing switch 130 for a predetermined closure time interval, thereby generating a current pulse having a pulse duration T1 corresponding to the closure time interval. Pulse duration T1 may be in the range of 1 microsecond to 500 microseconds, particularly 10 microseconds to 300 microseconds, preferably 15 microseconds to 120 microseconds, and most preferably 30 microseconds to 100 microseconds. At the end of the closed time interval, the microprocessor 160 reopens the switch 130 for a predetermined open time interval, thereby interrupting the passage of current to the heating arrangement 110. The open time interval corresponds to the time interval between two consecutive power pulses, which for item detection may be in the range of 50 milliseconds to 2 seconds, particularly 100 milliseconds to 2 seconds, and preferably 500 milliseconds to 1 second. The opening and closing of the switch 130 may occur at regular time intervals to generate periodic power pulses for periodically powering the induction heating arrangement 110. Thus, the sum of the closed time interval and the open time interval, or the sum of the pulse duration and the time interval between two consecutive power pulses, corresponds to the periodicity of the series of pulses. Generally, the time interval T2 between two consecutive probe power pulses should be selected to balance the effects of energy depletion and the performance of the user experience. The pulse duration T1 should be as short as possible while still being sufficient to provide a reliable measurement of the current pulse.

[0096] FIG. 6 is a graph showing an exemplary embodiment of a series of current pulses I_DC over time t, with a pulse duration T1 of 100 microseconds and a time interval T2 between two successive power pulses of 1 second. Of course, these values ​​are merely exemplary and may vary. As long as no aerosol-generating article is inserted, the current measuring device 140 measures a current having a value I_NA for each pulse (where "NA" stands for "no article"). As explained, the measured value I_NA depends on the ohmic load 114, which is equal to the ohmic resistance of the inductor L2. In contrast, when a user inserts an article 10 into the cavity 103, the ohmic load 114 increases because the ohmic load is equal to the ohmic resistance of the inductor L2 and the ohmic resistance of the susceptor 30. Due to the increased ohmic load, the current absorbed by the heating assembly decreases. Therefore, the current measuring device 140 measures a current pulse having a value I_A that is lower than I_NA (where "A" stands for "article inserted"). The difference ΔI_DC between I_NA and I_A is recorded by the microcontroller 160 which triggers the start of the heating mode.

[0097] According to the present invention, it has been found that any condition detection involving the heating arrangement 110 consumes the least amount of energy if it is actively energized only when the condition detection is actually needed. Typically, condition detection is primarily needed at the beginning of a user experience, immediately prior to the actual heating operation of the device 100, i.e., when the heating arrangement 110 is not yet operational but is about to be used. To provide a suitable trigger for activating the condition detection, the present invention proposes using the position and / or movement of the closure 107, particularly the open position and / or movement to the open position, because it is a highly suitable indicator of the beginning of a user experience. Conversely, closing the closure 107 of the cavity may be a highly suitable indicator of the end of a user experience and therefore a highly suitable trigger for stopping the heating operation of the device. Advantageously, using the position and / or movement of the closure 107 as a trigger does not require additional user interaction with the device, such as pressing a button. Instead, the trigger advantageously utilizes an action taken by the user, whether at the beginning or end of a user experience.

[0098] To enable the position and / or movement of the closure 107 to be used as a trigger, the aerosol generating device 100 includes a closure detector 108 arranged and configured to detect at least one of when the closure 107 is in an open position or when the closure 107 moves from a closed position to an open position. The closure detector 108 is operably connected to control circuitry of the device 100, which is then configured to initiate condition detection by energizing the induction heating arrangement 110 in response to a signal from the closure detector 108 indicating that the closure is in an open position or moving from a closed position to an open position, respectively.

[0099] In this embodiment, the closure detector 108 is a magnetic closure detector 108 including a permanent magnet 108a attached to the closure part 107 and a magnetic sensor 108b fixedly arranged within the device housing 101 such that the magnetic sensor 108b senses the magnetic field of the permanent magnet 108a when the closure part 107 is in the open position or moves to the open position (see FIGS. 4a and 4b). In particular, the permanent magnet 108a and the magnetic sensor 100b may be arranged such that the magnetic sensor 100b senses the magnetic field of the permanent magnet 108a only when the closure part 107 is in the open position. Advantageously, this arrangement ensures that the opening can be reliably detected, particularly without external interference. To ensure such interference-free detection, the permanent magnet 108a is preferably arranged adjacent to the magnetic sensor 108b at a distance of at most 3 millimeters, particularly at most 2.5 millimeters, when the closure part 107 is in the open position (see FIGS. 4a and 4b). Conversely, the permanent magnet 108a is preferably at least 40 millimeters away from the magnetic sensor 108b when the closure 107 is in the closed position (see Figures 3a and 3b).

[0100] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5%. Within this context, the number A may be considered to include values ​​that are within the typical standard error for the measurement of the property that it modifies. In some instances, the number A, as used in the appended claims, may deviate by the percentages recited above, as long as the deviation does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. An aerosol generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated, said device comprising: an apparatus housing including a cavity for removably receiving at least a portion of an aerosol-generating article, said article including said aerosol-forming substrate and an induction-heated susceptor for heating said substrate, said cavity including an insertion opening for inserting said article into said cavity; a closure portion reversibly movable relative to the device housing between a closed position in which the closure portion covers the insertion opening and an open position in which the insertion opening is not obstructed by the closure portion; an induction heating arrangement configured to generate an alternating magnetic field within the cavity for inductively heating the susceptor of an article when the article is received within the cavity; a closure detector disposed and configured to detect at least one of when the closure is in the open position or when the closure moves from the closed position to the open position; operatively connected to the induction heating arrangement and the closure detector; energizing the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in the open position or moving from the closed position to the open position, respectively; - determining at least one characteristic or a change in at least one characteristic of the induction heating arrangement depending on at least one of the type, presence, absence, position and movement of the susceptor within the cavity during energization of the induction heating arrangement; - detecting at least one particular condition associated with the item based on the determined characteristic or a change in the determined characteristic of the induction heating arrangement.

2. The aerosol generating device of claim 1, wherein the control circuit is configured to detect at least one of the item type, insertion, presence, absence, position, and displacement of an item in the cavity based on the determined characteristic or a change in the determined characteristic of the induction heating arrangement.

3. 3. An aerosol generating device as described in any one of claims 1 or 2, wherein the control circuit is configured to generate power pulses to intermittently turn on the induction heating arrangement and to determine the at least one characteristic or the change in the at least one characteristic of the induction heating arrangement during one or more power pulses.

4. An aerosol generating device as described in any one of claims 1 to 3, wherein the closure detector is arranged and configured to further detect at least one of when the closure portion is in the closed position or when the closure portion moves from the open position to the closed position.

5. 5. The aerosol generating device of claim 4, wherein the control circuit is configured to stop energizing the induction heating arrangement in response to a signal from the closure detector indicating that the closure is in the closed position or when the closure moves from the open position to the closed position.

6. 6. The aerosol generating device of claim 1, wherein the occlusion detector comprises one of a magnetic occlusion detector, an optical occlusion sensor, a capacitive occlusion detector, an inductive occlusion detector, and an electromechanical switch.

7. The aerosol generating device of claim 6, wherein the magnetic closure detector includes at least one magnetic sensor fixedly arranged within the device housing to detect when the closure is in the open position or when the closure moves from the closed position to the open position, and at least one associated permanent magnet attached to the closure so that the magnetic sensor senses the magnetic field of the associated permanent magnet only when the closure is in the open position or moves to the open position, particularly when the closure is in the open position.

8. 8. The aerosol generating device of claim 7, wherein the at least one magnetic sensor is arranged adjacent to the at least one associated permanent magnet at a distance of at most 3 millimeters, in particular at most 2.5 millimeters, when the closure is in the open position, and / or the at least one magnetic sensor is separated from the associated permanent magnet by at least 5 millimeters, in particular at least 7.5 millimeters, preferably at least 10 millimeters, more preferably at least 15 millimeters, when the closure is in the closed position.

9. The aerosol generating device of claim 6, wherein the optical closure detector includes a light sensor for detecting light, particularly ambient light, and the light sensor is arranged so that it is at least partially covered by the closure or by a cover attached or disposed on the closure when the closure is in the open position or the closed position, respectively, and is not obstructed by the closure or by the cover attached or disposed on the closure when the closure is in the closed position or the open position.

10. The aerosol generating device of claim 6, wherein the optical closure detector includes a light emitter and a light receiver for sensing light transmitted from the light emitter, and the light emitter and the light receiver are blocked by the closure or by a cover attached or disposed on the closure when the closure is in the open position or the closed position, respectively, and are not blocked by the closure or by the cover attached to the closure when the closure is in the closed position or the open position.

11. 7. The aerosol generating device of claim 6, wherein the electromechanical switch is activated by the closure or by an actuator attached or disposed on the closure when the closure is in the open position or the closed position, respectively, and is stopped by the closure or by the actuator attached to the closure when the closure is in the closed position or the open position.

12. The aerosol generating device of claim 6, wherein the electromechanical switch is activated by the closure portion or by an actuator attached or disposed on the closure portion when the closure portion moves from the open position to the closed position or when the closure portion moves from the closed position to the open position, and preferably the electromechanical switch is stopped by the closure portion or by the actuator attached or disposed on the closure portion when the closure portion moves from the closed position to the open position or when the closure portion moves from the open position to the closed position.

13. The closure portion is a sliding closure part slidably guided on the device housing between the open position and the closed position; a pivoting closure pivotally mounted on the device housing; - an iris diaphragm closure.

14. The control circuit - initiating a heating operation of the induction heating arrangement in response to detecting the insertion of an article into the cavity; - disabling the heating operation of the induction heating arrangement in response to detecting the absence of an item from the cavity.

15. 15. An aerosol generation system comprising: an aerosol generating device according to any one of claims 1 to 14; and an aerosol-generating article for use in the aerosol generating device, the aerosol-generating article being removably receivable within the cavity of the device and including at least one aerosol-forming substrate, and at least one induction heating susceptor for heating the substrate by interaction of the susceptor with an alternating magnetic field provided by the induction heating arrangement of the device.

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