Electricly operated aerosol generator with airflow detection means within the device

Abstract

The present invention relates to an electrically operated aerosol generating device for generating an aerosol. The device includes an air path that extends through the device and is configured to support an airflow within the device. The device further includes a sound generating member arranged in fluid communication with the air path and configured to generate a sound caused by the airflow passing through the sound generating member when a user puffs upon use of the device. The device further includes a puff detector comprising a vibration sensor. The vibration sensor is fluidly separated from the air path and is configured to detect sound propagating from the sound generating member to the vibration sensor. The present invention also relates to an aerosol generating system comprising such a device and an aerosol generating article comprising an aerosol forming substrate.

Description

Technology Field

[0001] The present invention relates to an electrically operated aerosol generating device for generating an aerosol, in particular for generating an aerosol by releasing a material of an aerosol-forming substrate into an airflow, wherein the device comprises means for detecting the airflow within the device. The present invention also relates to an aerosol generating system comprising such a device and an aerosol generating article comprising an aerosol-forming substrate. Background Technology

[0002] Electricly operated aerosol generators used to generate inhalable aerosols by releasing a substance of an aerosol-forming substrate into an airflow are generally known from the prior art. For example, such a device may include an electric heater for heating an aerosol-forming substrate capable of releasing a volatile compound that forms an inhalable aerosol when heated. As another example, such a device may include a sprayer for dispersing particles or droplets of the aerosol-forming substrate into an airflow to form an inhalable aerosol, for instance.

[0003] To maintain the user experience as uniformly as possible, material release from the aerosol-forming substrate must be maintained at a specific level when the user puffs. However, material release can vary during consumption, particularly due to the airflow drawn through the system during the user's puff. For this reason, proper puff detection is important for the precise control of material release. Puff detection can be achieved, for example, by measuring the pressure drop of the airflow through the device when the user puffs. To this end, many devices include pressure sensors that are in direct fluid communication with the air path passing through the device to directly detect the airflow indicating the user taking the puff. However, in such arrangements, the sensors are directly exposed to conditions within the air path, for example, thermal and moisture effects resulting from aerosol formation. Consequently, proper airflow detection may be negatively affected, which could lead to defective or even non-functional puff detection.

[0004] Therefore, it would be desirable to provide an electric aerosol generator comprising means for puff detection by utilizing the advantages of conventional solutions while mitigating their limitations. In particular, it would be desirable to have an electric aerosol generator comprising improved means for detecting airflow through a device indicating a user's puff.

[0005] According to the present invention, an electric aerosol generating device for generating an aerosol is provided, in particular, an electric aerosol generating device for generating an aerosol by releasing a material of an aerosol-forming substrate into an airflow. The device includes an air path that extends through the device and is configured to support the airflow within the device. The device further includes a sound generating member arranged in fluid communication with the air path and configured to generate a sound caused by the airflow passing through the sound generating member when the user puffs. Additionally, the device includes a puff detector comprising a vibration sensor. The vibration sensor is fluidly separated from the air path—at least within the device—and is configured to detect sound propagating from the sound generating member to the vibration sensor. Thus, the detection of sound propagating from the sound generating member to the vibration sensor can enable the detection of the airflow through the device indicating the user's puff.

[0006] According to the present invention, it has been recognized that an indication that a user is taking a puff can be reliably detected by using the airflow to generate air vibrations (sound) or vibrations of at least a portion of the device being propagated, and thus can be remotely detected by a vibration sensor. Due to the possibility of remotely detecting propagating vibrations, the vibration sensor may be arranged to be fluidly separated from the air path within the device. Advantageously, the fluidly separated arrangement of the vibration sensor makes the detection of airflow and puffs less susceptible to error and thus more reliable. Additionally, it has been recognized that the use of a sound-generating member can act as an amplifier of the airflow through the air path in that it generates vibrations transmitted to the remote vibration sensor.

[0007] As used, the terms "sound" or "propagating vibration" essentially refer to mechanical sound waves propagating through a gaseous, fluid, or solid medium of an aerosol generating device, particularly air or structural components (solid materials). The term "sound wave" refers to a type of energy propagation caused by the adiabatic compression and decompression of a medium (the air or solid materials of the device, respectively).

[0008] The term "sound wave" or "sound" may relate to sound waves or sounds that are perceptible or audible to humans by auditory perception, particularly by hearing. The frequencies audible to humans are generally within the range of 20 Hertz (Hz) to 20,000 Hertz (Hz). Likewise, the term "sound wave" or "sound" may relate to sound waves or sounds in a frequency range exceeding the frequency spectrum audible to humans, particularly in a frequency range exceeding 20,000 Hertz (Hz) or in a frequency range below 20 Hertz (Hz). Thus, the term "sound wave" or "sound" may relate to ultrasound or sound, or infrasound or sound.

[0009] Generally, the sound generating member may be any mechanical member suitable for generating sound by an airflow passing through a vibration generating member. To this extent, the sound generating member may also be described as an airflow-driven sound generating member.

[0010] To generate sound, the sound-generating member may include a sound-generating displacement structure configured to partially displace an airflow as it passes through the sound-generating displacement structure. As in displacement aerophones such as pipes, whistles, and flutes, the airflow passing through the sound-generating displacement structure is divided and deformed by the displacement structure to cause vibration in the airflow, namely adiabatic compression and decompression of the airflow. Typically, the sound-generating displacement structure may include one or more edges, particularly sharp edges where the airflow meets as it passes through the sound-generating displacement structure.

[0011] Preferably, the sound-generating displacement structure comprises at least one of one or more grooves or one or more ridges, one or more dimples, or one or more protrusions. When air passes along one or more grooves, dimples, protrusions, or ridges, respectively, the layered airflow in contact with one or more grooves, dimples, protrusions, or ridges is converted into a turbulent airflow due to collision with one or more grooves or ridges. Thus, a portion of the kinetic energy of the airflow, i.e., dynamic pressure, is converted into static pressure. If the sound-generating displacement structure comprises a plurality of grooves or ridges, the partial displacement of the airflow creates a plurality of alternating high-pressure and low-pressure regions within the airflow, which cause vibration in the airflow, i.e., sound.

[0012] Generally, the frequency and amplitude of sound depend on the shape, height or depth, and periodicity of the grooves, dimples, protrusions, or ridges, respectively. Additionally, the frequency and amplitude of sound depend on the velocity of the airflow passing along the vibration-generating displacement structure. Thus, the shape, height, or depth of the grooves, dimples, protrusions, or ridges, and—in the case of multiple grooves, dimples, protrusions, or ridges—the periodicity of the grooves, dimples, protrusions, or ridges can be designed to selectively generate vibrations having a specific frequency (frequency spectrum) and amplitude, for example.

[0013] One or more grooves, or one or more ridges, or one or more grooves and one or more ridges may have any type of shape suitable for partially displacing airflow. Preferably, one or more grooves, or one or more ridges, or one or more grooves and one or more ridges may include one of a triangular shape, a curved shape, particularly a sinusoidal shape, or a rectangular shape. As used, the shape of one or more grooves or ridges refers to the cross-sectional shape of one or more grooves or ridges, as seen in a cross-section perpendicular to the length extension of each of the one or more grooves or ridges.

[0014] Generally, multiple grooves or ridges may be distributed uniformly or non-uniformly along a sound-generating displacement structure. Preferably, the sound-generating displacement structure includes a periodic pattern. That is, the grooves or ridges, or both grooves and ridges, are arranged in a periodic pattern with a constant distance between each pair of adjacent grooves or ridges. The periodic pattern proves to be advantageous in relation to the generation of vibrations having a specific, particularly narrow-band frequency spectrum.

[0015] Depending on the frequency of the sound to be generated, the periodic pattern may have periodicity in the range of 0.5 ridges or grooves per millimeter to 10 ridges or grooves per millimeter, particularly 1 ridge or groove per millimeter to 5 ridges or grooves per millimeter, preferably 2 ridges or grooves per millimeter to 4 ridges or grooves per millimeter. That is, the periodic pattern may have a periodic length in the range of 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, preferably 0.25 mm to 0.5 mm. Accordingly, the generated displacement structure may include a plurality of ridges or grooves, or a plurality of ridges and grooves, having a distance between each pair of adjacent grooves or ridges in the range of 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, preferably 0.25 mm to 0.5 mm.

[0016] For example, if the periodic pattern of the sound-generating displacement structure has a period length of 0.25 mm and the speed of the airflow passing through the sound-generating displacement structure is 10 m / s, a sound with a frequency of about 40 kilohertz (kHz) can be generated.

[0017] The periodic pattern may be a linear periodic pattern. The periodic pattern may be one-dimensional, such as an array of multiple parallel grooves or ridges. That is, the pattern contains periodicity along only one direction. The periodic pattern may be multi-dimensional, particularly two-dimensional, that is, the pattern contains periodicity along more than one direction, particularly two directions. For example, the pattern may include a first periodicity along a first direction and a second periodicity along a second direction. The first direction and the second direction may be transverse directions, particularly perpendicular to each other. As an example, the periodic pattern may include a first array of multiple parallel first grooves or first ridges having a first periodicity along a first direction, and a second array of multiple parallel second grooves or second ridges having a second periodicity along a second direction. In particular, such a periodic pattern may be a cross pattern or a grid pattern.

[0018] The periodic pattern may be a non-linear periodic pattern. For example, the periodic pattern may include a plurality of curved, particularly ring-shaped grooves or curved, particularly ring-shaped ridges. The periodic pattern may include a concentric ring pattern forming a plurality of ring-shaped grooves or a plurality of ring-shaped ridges. The ring pattern or ring shape may be circular, elliptical, oval, rectangular, quadratic, or polygonal. Symmetrically, the periodic ring pattern may prove advantageous in relation to the arrangement of sound-generating displacement structures at the distal end surface of a cylindrical receiving cavity.

[0019] As another example, the periodic pattern may include a helical pattern formed by spiral grooves or ridges.

[0020] As another example, the periodic pattern may include a honeycomb pattern comprising a plurality of grooves or ridges that form the outline of the honeycomb pattern.

[0021] To improve sound generation, at least one length extension of one or more grooves or one or more ridges may be perpendicular to the transverse direction, particularly to the direction of airflow passing through the sound-generating member when the device is in use.

[0022] At least one of the height of the ridge or the depth of the groove may be constant along the sound-generating displacement structure in the direction of the airflow passing through the sound-generating member when the device is in use. Alternatively, at least one of the height of the ridge or the depth of the groove may be variable and may increase along the sound-generating displacement structure in the direction of the airflow passing through the sound-generating member when the device is in use. This may allow the sound generation to adapt to the geometry and dimensions of the air path, for example, to provide a specific resistance to suction (RTD).

[0023] Preferably, the sound-generating member, in particular the sound-generating displacement structure, is part of a wall member that defines at least a portion of the air path through the device. Advantageously, this can simplify the manufacture and assembly of the device. In particular, having a sound-generating displacement structure integral with the wall member of the device allows for a compact design of the device. For example, the sound-generating displacement structure may include one or more grooves, or one or more ridges, or one or more grooves and one or more ridges formed in the wall member of the device that defines at least a portion of the air path through the device.

[0024] Likewise, the sound-generating member, in particular the sound-generating displacement structure, may be a separate member or element attached to the wall member, in particular, separated from the wall member that defines at least a portion of the air path through the device.

[0025] The sound-generating displacement structure is preferably a rigid structure. As such, the sound-generating displacement structure as a whole, or the structural components of the sound-generating displacement structure, do not experience center of mass deflection. However, this does not exclude the possibility that sound can be propagated through the sound-generating displacement structure.

[0026] Alternatively or additionally to the sound-generating displacement structure, the sound-generating member may include at least one airflow-driven vibrating element for periodically blocking the airflow passing through the vibrating element. As in intermittent aerophones, particularly reed aerophones such as oboe or clarinet, the airflow is induced against a flexible vibrating element, such as a lamella or a pair of lamellas, causing the vibrating element to vibrate. Due to the airflow-driven vibration of the flexible vibrating element, the airflow passing through the vibrating element is periodically blocked, causing the air to move and produce sound.

[0027] Accordingly, at least one vibrating element may include a lamella or a reed or a pair of reeds or a pair of lamellas.

[0028] Likewise, at least one vibrating element may include a restricted movable element for periodically blocking the airflow passing through the vibrating element. To restrict free movement, the movable element may be arranged within a cage like the peas of a pea whistle. Likewise, the movable element may be restricted by coupling the movable element to one end of a spring element, where the other end of the spring element is fixedly attached within the device.

[0029] Of course, the sound-generating member may include multiple vibrating elements, for example, multiple lamellas or reeds. Having multiple vibrating elements advantageously enhances the amplitude of the generated sound, which ultimately facilitates sound propagation toward the vibration sensor.

[0030] As described above, the amplitude and frequency / frequency spectrum of the generated sound may be influenced by the dimensions and configuration of the air path and the sound generating member. In order to prevent the user of the device from perceiving the generated sound, particularly to avoid unwanted noise exposure, the generated sound is preferably outside the frequency spectrum audible to humans, and more preferably outside the frequency spectrum audible to many animals, especially pets such as dogs or cats. Accordingly, the air path and the sound generating member may be configured so that when the device is used, the generated sound is in a frequency range greater than 15 kilohertz (kHz), preferably greater than 20 kilohertz (kHz), and more preferably greater than kilohertz (kHz).

[0031] To have a vibration sensor fluidly separated from the air path through the device—at least within the device—the vibration sensor may be arranged within a compartment of the device that fluidly separates it from the air path through the device—at least within the device. As a result, the vibration sensor does not have direct fluid communication with the air path, and in particular, does not come into direct contact with the fluid (air, aerosol, aerosol particles) passing through the air path. This does not exclude the possibility that the vibration sensor and the air path through the device may have indirect fluid communication, for example, through direct fluid communication with the ambient air surrounding the device, which may eventually have direct fluid communication with the air path through the device, for example, through the air inlet or outlet of the device. In this configuration, the vibration sensor is still sufficiently insulated from any fluid (air, aerosol, aerosol particles) passing through the air path.

[0032] Therefore, the compartment of the device that is fluidly separated from the air path can fluidly communicate with the device environment, particularly the surrounding air surrounding the device.

[0033] Alternatively, the compartment of the device, which is fluidly separated from the air path through the device, can also be fluid-sealed from the device environment, particularly the ambient air surrounding the device.

[0034] Although the vibration sensor is fluidly separated from the air path through the device, sound generated by the sound-generating member can easily propagate from the sound-generating member toward the vibration sensor through different media. That is, sound can propagate through the air within the device, through the ambient air surrounding the device, and through solid materials of the device, such as, for example, wall members of the device, such as wall members defining at least a portion of the air path or wall members separating the aforementioned compartment from the air path. Depending on the sound propagation characteristics of different media and the physical structure and dimensions of the device, sound can propagate directly from the sound-generating member toward the vibration sensor. Alternatively or additionally, sound can propagate from the sound-generating member to the vibration sensor through the device environment. That is, sound can at least partially exit the device and re-enter the device before reaching the vibration sensor.

[0035] A vibration sensor may be arranged within a device such that sound transmission into the vibration sensor occurs from the air surrounding at least a portion of the vibration sensor. Accordingly, the vibration sensor may be arranged within a device such that it is at least partially surrounded by, for example, a fluid, particularly air.

[0036] Likewise, the vibration sensor may be arranged within the device such that the transmission of sound into the vibration sensor occurs from the solid material of the device component that the vibration sensor contacts. For example, the vibration sensor may be arranged on a wall member of the device, such as a wall member of the device that fluidly separates the sensor from the air path. In particular, the vibration sensor may be arranged on the side of a wall member facing the side of the wall member that defines at least a portion of the air path through the device.

[0037] A vibration sensor may include an electro-acoustic transducer. An electro-acoustic transducer is a device configured to convert acoustic energy into electrical energy. Depending on the nature of sound transmission into the vibration sensor, the vibration sensor may include, for example, a microphone, an accelerometer, a strainometer, or a piezoelectric acoustic transducer or a magnetoacoustic transducer.

[0038] A piezoelectric acoustic transducer is a device that uses the piezoelectric effect to measure changes in pressure, acceleration, deformation, or force caused by sound, and detects sound by converting the measured changes into electrical signals. Similarly, a magnetoacoustic transducer is a device that uses electromagnetic induction to measure changes in pressure, acceleration, deformation, or force caused by sound, and detects sound by converting the measured changes into electrical signals.

[0039] Similarly, accelerometers or strainometers can be used to measure the movement and vibration of structures exposed to dynamic loads caused by sound coupling to these types of sensors. A strainometer is a sensor whose resistance varies according to the applied force. It converts force, pressure, or tension into a change in electrical resistance that can be measured. An accelerometer measures the appropriate acceleration of a sensing mass, such as a membrane, that responds to oscillations in air pressure or to vibrations / acoustics in a solid body to which the sensing mass is mechanically coupled.

[0040] The microphone can be an electromagnetic microphone (also known as a dynamic or moving coil microphone) that uses electromagnetic induction to convert acoustic energy into electrical energy. Electromagnetic microphones are robust, relatively inexpensive, and moisture-resistant. Electromagnetic microphones use the same dynamic principle as loudspeakers, but in the opposite way. A small moving induction coil is attached to a diaphragm, positioned within the magnetic field of a permanent magnet. When sound enters the microphone, the sound waves move the diaphragm. As the diaphragm vibrates, the coil moves within the magnetic field, generating a variable current within the coil through electromagnetic induction. This type of microphone can also be referred to as a magnetoacoustic transducer or be a specific example of a magnetoacoustic transducer.

[0041] The microphone may be an electrostatic microphone, such as a condenser microphone, an electret microphone, or a piezoelectric microphone. The latter may also be indicated as a piezoelectric acoustic transducer or be a specific example of a piezoelectric acoustic transducer, the details of which will be described later.

[0042] The microphone may be a fiber optic microphone. A fiber optic microphone converts sound waves into electrical signals by detecting changes in the intensity of light passing through an optical fiber. During operation, light from a laser light source travels through the optical fiber to illuminate the surface of a reflective diaphragm. The sound vibrations of the diaphragm regulate the intensity of the light reflected from the diaphragm in a specific direction. The regulated light is transmitted through a second optical fiber to a photodetector, which converts the intensity-regulated light into an electrical signal. Fiber optic microphones have a high dynamic and frequency range. Advantageously, fiber optic microphones do not interfere with electric, magnetic, or electrostatic fields. Therefore, fiber optic microphones are ideal for use in electrically operated aerosol generators, particularly in induction heating aerosol generators.

[0043] The device may include a device housing that includes an air path through the device. The device housing may be configured to accommodate an aerosol-forming substrate that includes a substance to be released into an airflow through the air path.

[0044] Generally, an aerosol generator may include at least one air inlet through which air can enter an air path. As such, the air inlet can be considered as the starting point of the air path through the device. Similarly, the aerosol generator may include at least one air outlet through which air can leave the air path through the device. As such, the air outlet can be considered as the ending point of the air path through the device. The air outlet may be provided, for example, in the mouthpiece portion of the device.

[0045] An aerosol generating device may include a receiving cavity for removably receiving at least a portion of an aerosol generating article comprising an aerosol forming substrate or a substrate.

[0046] The receiving cavity may include an insertion opening into which an aerosol-forming substrate or an aerosol-generating article can be inserted. As used herein, the direction in which the aerosol-forming substrate or an aerosol-generating article is inserted is indicated as the insertion direction. Preferably, the insertion direction corresponds to an extension of the longitudinal axis of the receiving cavity, particularly the central axis.

[0047] When inserted into the receiving cavity, at least a portion of the aerosol-generating article may still extend outward through the insertion opening. The portion extending outward is preferably provided for interaction with the user, particularly to be taken into the user's mouth. Thus, during use of the device, the insertion opening may be close to the user's mouth.

[0048] Accordingly, 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 generally designated with the prefix "proximal." The section positioned further away is designated with the prefix "distal."

[0049] In relation to this practice, the receiving cavity may be arranged or located within the proximal part of the aerosol generator. The insertion opening may be arranged or located at the proximal end of the aerosol generator, particularly at the proximal end of the receiving cavity.

[0050] The air path through the device may extend at least partially through a wall that defines at least a portion of the receiving cavity. Such a configuration is described, for example, in WO 2013 / 102609 A2.

[0051] Additionally or alternatively, an air path through the device may extend at least partially along the inner surface of the receiving cavity. To this end, the receiving cavity may include a plurality of protrusions extending into the interior of the receiving cavity. Preferably, the plurality of protrusions are spaced apart from each other so that at least a portion of the airflow passage or the airflow passage through the device is formed between neighboring protrusions, that is, formed by a gap (free space) between neighboring protrusions. Furthermore, the plurality of protrusions may be configured to contact at least a portion of an aerosol-forming substrate or an aerosol-generating article to hold a substrate or article within the receiving cavity. An example of such a configuration is described in WO 2018 / 050735 A1.

[0052] In connection with this configuration, the air inlet of the device is preferably realized at an insertion opening of a receiving cavity used to insert a substrate or article into the cavity. When the substrate or article is received into the cavity, air is drawn into the receiving cavity from the rim of the insertion opening and further drawn through that part of the air path formed between the inner surface of the receiving cavity and the outer circumference of the aerosol-forming substrate or aerosol-generating article.

[0053] Preferably, a portion of the air passage is extended through an aerosol-forming substrate or article. Thereby, the air passage can pass directly into the user's mouth. Alternatively, the air passage may be extended through a mouthpiece portion of the device leaving an air outlet within the mouthpiece portion.

[0054] The aerosol generating device may include one or more end stops arranged within a receiving cavity, particularly at the distal end of the receiving cavity. The one or more end stops are preferably configured to limit the insertion depth of an aerosol-forming substrate or aerosol-generating article into the receiving cavity. In particular, the one or more end stops may be configured to prevent the aerosol-forming substrate or aerosol-generating article from coming into contact with the distal end surface of the receiving cavity facing the insertion opening of the receiving cavity at the proximal end of the receiving cavity. Thus, the one or more end stops advantageously provide free space within the distal portion of the receiving cavity, thereby allowing free airflow between the distal end of the receiving cavity and the distal end of the aerosol-generating article when the substrate or article is received within the receiving cavity. The one or more end stops may include a contact surface that the aerosol-generating article, particularly the distal end of the aerosol-generating article, may come into contact with when the article is received within the receiving cavity.

[0055] Preferably, the aerosol generating device may include a plurality of separate end stops arranged within the receiving cavity, particularly at the distal end of the receiving cavity, for example, three end stops.

[0056] Multiple end stops may be symmetrically arranged around the longitudinal axis of the receiving cavity, particularly the central axis. Preferably, the multiple end stops may be arranged equally spaced around the longitudinal axis of the receiving cavity, particularly the central axis. As previously mentioned, this enables free airflow around the end stops and the article received within the receiving cavity.

[0057] Generally, the receiving cavity may have any suitable shape. In particular, the shape of the receiving cavity may correspond to the shape of the aerosol-forming substrate or aerosol-generating article to be received therein. Preferably, the receiving cavity may have a substantially cylindrical shape or a tapered shape, with respect to a substantially conical or substantially truncated conical shape.

[0058] Likewise, the receiving cavity may have any suitable cross-section as seen in a plane perpendicular to the longitudinal axis of the receiving cavity or perpendicular to the insertion direction of the article. In particular, the cross-section of the receiving cavity may correspond to the shape of the aerosol-generating article to be received therein. Preferably, the receiving cavity has a substantially circular cross-section. Alternatively, the receiving cavity may have a substantially elliptical cross-section, a substantially ovate 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 foregoing shapes and cross-sections refer to the shape or cross-section of the receiving cavity, preferably without considering any protrusions.

[0059] The receiving cavity can be formed as a receiving cavity module, in particular, as a tubular sleeve, which can be inserted into the main body of the aerosol generator. Advantageously, this allows for a modular assembly of the aerosol generator.

[0060] Alternatively, at least a portion of the receiving cavity may be formed integrally with the main body. By providing at least a portion of the receiving cavity as part of the main body, the amount of part required to construct the aerosol generating device may be reduced.

[0061] A sound-generating member may be located at the distal end portion of the receiving cavity, in particular on the distal end surface of the receiving cavity. The distal end surface of the receiving cavity may be formed by a wall member that separates the receiving cavity from other parts of the device, in particular a part of the device including a vibration sensor and / or electronic components (electrical circuit, controller, power supply). Preferably, a vibration sensor is arranged on the side of the wall member facing the side of the wall member defining the distal end surface of the receiving cavity.

[0062] In addition to the vibration sensor, the puff detector may further include an electrical circuit for converting the output signal of the vibration sensor into a signal representing sound. The electrical circuit may include at least one of a transimpedance amplifier for current-voltage conversion, an inverting signal amplifier, a differential-single-stage converter, an analog-to-digital converter, and a microcontroller.

[0063] The puff detector or electrical circuit may further include one or more electronic filters for filtering the output signal of the vibration sensor. Advantageously, the filtering may allow for the reduction of different types of noise, particularly parasitic noise detected by the vibration sensor.

[0064] Generally, aerosol generation, particularly the release of material from an aerosol-forming substrate into an airflow through a device, can be realized in different ways as further described above.

[0065] For example, the device may include a nebulizer for dispersing particles or droplets of an aerosol-forming substrate into an airflow to form, for instance, an inhalable aerosol. The nebulizer may be an ultrasonic nebulizer.

[0066] Alternatively, the aerosol generating device may include an electric heater for heating an aerosol-forming substrate capable of releasing a volatile compound that forms an inhalable aerosol when heated and released into an airflow.

[0067] The electric heater of the aerosol generating device may be an inductive heater. The inductive heater may include an inductor configured to generate an alternating, particularly high-frequency electromagnetic field within the device, particularly within the receiving cavity of the device as described above. The alternating, particularly high-frequency electromagnetic field may be in the range of 500 kHz (kilohertz) to 30 MHz (megahertz), particularly 5 MHz to 15 MHz, preferably 5 MHz to 10 MHz. The alternating electromagnetic field is used to inductively heat a susceptor that is in thermal contact with or thermally close to the aerosol-forming substrate to be heated. The inductor may be arranged, for example, to surround at least a portion of the susceptor and the aerosol-forming substrate during use of the device. The inductor may be an inductor coil, for example, a helical coil, arranged within the sidewall of the receiving cavity. For example, the inductor may be arranged to surround at least a portion of the receiving cavity.

[0068] Alternatively, the heater may be a resistive heater comprising a resistive heating element. The resistive heating element is configured to heat up when current passes through it due to the inherent ohmic resistance or resistive load of the resistive heating element. The resistive heating element may include at least one of a resistive heating wire, a resistive heating track, a resistive heating grid, or a resistive heating mesh. When the device is in use, the resistive heating element is in thermal contact with or thermally close to an aerosol-forming substrate to be heated.

[0069] The aerosol generating device may further include a controller operably coupled with a puff detector to determine the user's puff based on a signal provided by a vibration sensor, in particular based on a signal provided by a puff detector indicating airflow through the device's air passage.

[0070] The controller may be further configured to control the overall operation of the aerosol generator, in particular the heating process. Based on signals representing n airflows, the controller may be configured to control the release of material, in particular, from the aerosol-forming substrate into the airflow. For example, if the aerosol generator includes an electric heater for heating the aerosol-forming substrate, the controller may be operably coupled to the heater and configured to control the heating process to maintain the heating temperature at a specific level when the user puffs.

[0071] At least a portion of the controller and puff detector may be an integral part of the entire electrical circuit of the aerosol generator.

[0072] The aerosol generator may include a power supply, preferably a battery such as a lithium iron phosphate battery. Alternatively, the power supply may be another form of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that allows for the storage of sufficient energy for one or more user experiences. For example, the power supply may have a capacity sufficient to continuously generate aerosols for a period of about 6 minutes, or for a period of several times 6 minutes. In another example, the power supply may have a capacity sufficient to allow for the individual activation of a predetermined number of puffs or heating devices.

[0073] The present invention also relates to an aerosol generating system comprising an aerosol generating device according to the present invention and as described herein. The system further comprises an aerosol generating article comprising at least one aerosol forming substrate to be heated by the device, wherein at least a portion of the article is removablely accommodated in the device, particularly in a receiving cavity of the device.

[0074] The aerosol-generating article may be a consumable intended for single use, in particular. 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.

[0075] The article may include one or more of the following elements, a filter element, a cooling element, a first support element, a substrate element, and an optional second support element. Preferably, the aerosol generating article includes at least a first support element, a second support element, and a substrate element located between the first support element and the second support element.

[0076] All of the aforementioned elements may be arranged sequentially along the longitudinal axis of the article in the order described above, wherein the first support element is preferably arranged at the distal end of the article and the filter element is preferably arranged at the proximal end of the article. Each of the aforementioned elements may be substantially cylindrical. In particular, all elements may have the same external cross-sectional shape. Furthermore, the elements may be surrounded by an external wrapper, for example, to hold the elements together and maintain the desired cross-sectional shape of the rod-shaped article. Preferably, the wrapper is made of paper.

[0077] When induction heating an aerosol generating system, the article may further comprise a susceptor. The susceptor is positioned in thermal proximity or thermal contact with the aerosol generating substrate so that, when the article is received within the cavity of the device, the susceptor can be induction heated by an induction heating array upon use. For example, the susceptor may be a susceptor strip, a susceptor blade, a susceptor tube, or a susceptor sleeve. The susceptor may be part of a substrate element. As used herein, the term “susceptor” refers to an element capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This may result from hysteresis losses and / or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. Hysteresis losses occur in ferromagnetic or ferrimagnetic susceptors due to magnetic domains within the material that are switched under the influence of an alternating electromagnetic field. Eddy currents may be induced when the susceptor is electrically conductive. In the case of electrically conductive ferromagnetic or ferrimagnetic susceptors, heat can be generated due to both eddy currents and hysteresis losses.

[0078] At least one of the first support element and the second support element may include a central air passage. Preferably, at least one of the first support element and the second support element may include a hollow cellulose acetate tube. Alternatively, the first support element may be used to cover and protect the distal anterior end of the substrate element.

[0079] The aerosol cooling element is an element having a large surface area and low suction resistance, for example, 15 mmWG to 20 mmWG. When in use, the aerosol formed by volatile compounds released from the base element is drawn through the aerosol cooling element, which allows for the formation and cooling of the aerosol, before being delivered to the proximal end of the aerosol generating article.

[0080] The filter element, preferably, acts as part of the mouthpiece, or together with the aerosol cooling element. As used herein, the term "mouthpiece" refers to the part of the article through which the aerosol exits the aerosol-generating article.

[0081] Likewise, the aerosol generating article may be a capsule containing an aerosol-forming powder (as an aerosol-forming substrate) to be dispersed within an airflow to generate an aerosol.

[0082] Additional features and advantages of the aerosol generating system and aerosol generating article according to the present invention have already been described in relation to an aerosol generating device and apply equally.

[0083] As used herein, the term "aerosol-forming substrate" relates to a substrate capable of releasing a volatile compound capable of forming an aerosol.

[0084] In particular, the aerosol-forming substrate may be a substrate capable of releasing a volatile compound capable of forming an aerosol when heated. Such an aerosol-forming substrate is intended to be heated rather than burned to release the aerosol-forming volatile compound. The aerosol-forming substrate may be a solid aerosol-forming substrate, a liquid aerosol-forming substrate, a gel-type aerosol-forming substrate, or any combination thereof. That is, the aerosol-forming substrate may include, for example, both solid and liquid components. The aerosol-forming substrate may include a tobacco-containing material containing a volatile tobacco flavor compound released from the substrate upon heating. Alternatively or additionally, the aerosol-forming substrate may include a non-tobacco material. The aerosol-forming substrate may further include an aerosol-forming agent. Examples of suitable aerosol-forming agents are glycerin and propylene glycol. The aerosol-forming substrate may also include other additives and components, such as nicotine or flavoring agents. The aerosol-forming material may also be a paste-type material, a sachet of porous material containing the aerosol-forming material, or loose tobacco that is mixed with a gelling agent or adhesive, which may include a common aerosol-forming agent such as glycerin, for example, and compressed or molded into a plug.

[0085] Likewise, the aerosol-forming substrate may be an aerosol-forming powder. The aerosol-forming powder may include nicotine powder. The term "nicotine" means nicotine and nicotine derivatives such as nicotine salts. Accordingly, the nicotine powder may be a nicotine salt or a nicotine salt hydrate. Suitable nicotine salts or nicotine salt hydrates include, for example, nicotine tartrate, nicotine aspartate, nicotine lactate, nicotine glutamate, nicotine bitartrate, nicotine salicylate, nicotine fumarate, nicotine mono-pyruvate, nicotine hydrochloride, and combinations thereof.

[0086] Nicotine powder may have any suitable particle size distribution for lung delivery of nicotine to the user. In particular, at least about 90 weight percent (wt%) of the nicotine powder may have a particle size of about 10 µm or less, preferably about 7 µm or less. The nicotine powder preferably has an average diameter in the range of about 0.1 to about 10 µm, more preferably about 1 to about 7 µm, and particularly preferably about 2 to about 6 µm.

[0087] Nicotine powder particles can be surface modified, such as by coating nicotine salt particles. A preferred coating material is L-leucine. Particularly suitable nicotine powder particles include L-leucine coated nicotine deuterium, L-leucine coated nicotine glutamate, and L-leucine coated aspartate.

[0088] The capsule contains, preferably, about 5 to about 20 mg of nicotine powder, particularly about 10 mg of nicotine powder. Preferably, the capsule contains an amount of nicotine powder sufficient for a user to make about 10 to about 30 puffs.

[0089] The nicotine powder described herein is preferably free of a carrier. The absence of a carrier allows the nicotine powder to be inhaled or delivered to the user's lungs at an inhalation or airflow velocity similar to that of a conventional smoking system. Additionally, because the nicotine powder is free of a carrier, the airflow path of the inhaler may have a simple shape or simple configuration.

[0090] Nevertheless, the aerosol-forming powder may additionally contain carrier particles that increase the fluidity of the active particles and improve dosage uniformity by acting as a diluent or bulking agent within the formulation.

[0091] Alternatively or additionally to the nicotine powder, the aerosol-forming powder may include another active agent or component, such as an active pharmaceutical material. This active agent or component may be blended within the same capsule. The second active agent or component may have an average diameter size range similar to that of the nicotine powder described herein.

[0092] A non-limiting, non-comprehensive list of embodiments is provided below. Any one or more features of these embodiments may be combined with any one or more features of other embodiments, embodiments, or aspects described herein.

[0093] Example Ex1: An electrically operated aerosol generating device for generating an aerosol by releasing a substance of an aerosol-forming substrate into an air stream, wherein the device comprises:

[0094] An air path extending through the above device and configured to support the airflow within the above device;

[0095] A sound generating member arranged in fluid communication with the above air path and configured to generate a sound caused by an airflow passing through a sound generating member when the user puffs the device; and

[0096] An aerosol generating device comprising a puff detector including a vibration sensor, wherein the vibration sensor is fluidly separated from the air path and configured to detect sound propagating from the sound generating member to the vibration sensor, thereby enabling detection of airflow through the device representing a user's puff.

[0097] Example Ex2: An aerosol generating device in Example Ex 1, wherein the sound generating member comprises a sound generating displacement structure for displacing the airflow at least partially when passing through the sound generating displacement structure.

[0098] Example Ex3: An aerosol generating device according to Example Ex2, wherein the sound-generating displacement structure comprises at least one of one or more grooves or one or more ridges, one or more dimples, or one or more protrusions.

[0099] Example Ex4: An aerosol generating device according to Example Ex3, wherein the one or more groove length extensions, or the one or more ridge length extensions, or the one or more groove length extensions and the one or more ridge length extensions are perpendicular to the transverse direction, particularly to the direction of the airflow passing through the sound generating member when the device is in use.

[0100] Example Ex5: An aerosol generating device in any one of Examples Ex3 to Ex4, wherein the one or more grooves, or the one or more ridges, or the one or more grooves and the one or more ridges comprise one of a triangular shape, a sinusoidal shape, or a rectangular shape.

[0101] Example Ex6: An aerosol generating device in any one of Examples Ex3 to Ex5, wherein at least one of the height of the ridge or the depth of the groove is variable and, in particular, increases along the sound generating displacement structure in the direction of the airflow passing through the sound generating member when the device is used.

[0102] Example Ex7: An aerosol generating device in any one of Examples Ex3 to Ex6, wherein the plurality of grooves, ridges, dimples, or protrusions are distributed uniformly or non-uniformly along the air passage.

[0103] Example Ex8: An aerosol generating device in any one of Examples Ex1 to Ex7, wherein the sound generating member, in particular the sound generating displacement structure, is part of a wall member defining at least a portion of the air path through the device or is integral with the wall member.

[0104] Example Ex9: An aerosol generating device in any one of Examples Ex2 to Ex8, wherein the sound generating displacement structure comprises a periodic pattern.

[0105] Example Ex10: An aerosol generating device in Example Ex9, wherein the periodic pattern has a periodic length in the range of 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, preferably 0.25 mm to 0.5 mm.

[0106] Example Ex11: An aerosol generating device in any one of Examples Ex8 to Ex10, wherein the periodic pattern is a linear periodic pattern or a non-linear periodic pattern.

[0107] Example Ex12: An aerosol generating device in any one of Examples Ex8 to Ex11, wherein the periodic pattern is a one-dimensional periodic pattern, in particular an array of a plurality of parallel grooves or ridges.

[0108] Example Ex13: An aerosol generating device in any one of Examples Ex8 to Ex11, wherein the periodic pattern comprises a first array of a plurality of parallel first grooves or first ridges having a first periodicity along a first direction, and a second array of a plurality of parallel second grooves or second ridges having a second periodicity along a second direction.

[0109] Example Ex14: An aerosol generating device according to Example Ex 13, wherein the first direction and the second direction are transverse directions, particularly perpendicular to each other.

[0110] Example Ex15: An aerosol generating device in any one of Examples Ex8 to Ex10, wherein the periodic pattern comprises at least one of one or more curved, particularly ring-shaped grooves or one or more curved, particularly ring-shaped ridges.

[0111] Example Ex16: An aerosol generating device in any one of Examples Ex8 to Ex10, wherein the periodic pattern comprises a concentric ring pattern in which a plurality of ring-shaped grooves or a plurality of ring-shaped ridges are formed.

[0112] Example Ex17: An aerosol generating device in any one of Examples Ex8 to Ex10, wherein the periodic pattern comprises a spiral pattern having spiral-shaped grooves or ridges formed therein.

[0113] Example Ex18: An aerosol generating device in any one of Examples Ex3 to Ex10, wherein the periodic pattern may include a honeycomb pattern comprising a plurality of grooves or ridges forming the contour of a honeycomb pattern.

[0114] Example Ex19: An aerosol generating device in any one of Examples Ex2 to Ex18, wherein the sound-generating displacement structure is a rigid structure.

[0115] Example Ex20: An aerosol generating device in any one of the above-described embodiments, wherein the sound generating member, in particular the sound generating displacement structure, is a separate member or element attached to the wall member, in particular separated from the wall member defining at least a portion of the air path through the device.

[0116] Example Ex21: An aerosol generating device in any one of the above-described embodiments, wherein the sound generating member comprises at least one airflow-driven vibrating element configured to periodically block the airflow passing through the vibrating element.

[0117] Example Ex22: An aerosol generating device in Example Ex21, wherein at least one vibrating element comprises a lead or a lamellar or a pair of leads or a pair of lamellas.

[0118] Example Ex23: An aerosol generating device in any one of the above-described embodiments, wherein the air path and the sound generating member are configured such that the sound generated when the device is used is in a frequency range greater than 15 kilohertz (kHz), preferably 20 kilohertz (kHz), more preferably greater than kilohertz (kHz).

[0119] Example Ex24: An aerosol generating device in any one of the above-described embodiments, wherein the vibration sensor is arranged within a compartment of the device that is fluidly separated from the air path through the device.

[0120] Example Ex25: An aerosol generating device in which, in Example Ex 24, the partition of the device that is fluidly separated from the air path is fluidly in communication with the device environment.

[0121] Example Ex26: An aerosol generating device in which the compartment of the device, fluidly separated from the air path in Example Ex 24, is fluidly sealed from the device environment, particularly from the ambient air surrounding the device.

[0122] Example Ex27: An aerosol generating device in any one of the above-described embodiments, wherein the vibration sensor comprises a microphone, an accelerometer, a strain sensor, or a piezoelectric transducer or a magnetoacoustic transducer.

[0123] Example Ex28: An aerosol generating device in any one of the above-described embodiments, wherein the vibration sensor is arranged on the side of a wall member facing the side of the wall member that defines at least a portion of the air path through the device.

[0124] Example Ex29: An aerosol generating system in any one of the above-described examples, wherein the device comprises a receiving cavity for removably receiving at least a portion of an aerosol-forming substrate or an aerosol-generating article comprising said substrate.

[0125] Example Ex30: An aerosol generating device in Example Ex29, wherein the receiving cavity may include an insertion opening into which an aerosol forming substrate or an aerosol generating article can be inserted into the receiving cavity.

[0126] Example Ex31: An aerosol generating device in any one of Examples Ex29 to Ex30, wherein the air path extends at least partially along the inner surface of the receiving cavity and / or through a wall surface defining at least a portion of the receiving cavity.

[0127] Example Ex32: An aerosol generating device in any one of Examples Ex29 to Ex31, wherein the sound generating member is located on the distal end of the receiving cavity, particularly on the surface of the distal end of the receiving cavity.

[0128] Example Ex33: An aerosol generating device in any one of the above-described embodiments, wherein the puff detector comprises one or more electronic filters for filtering the output signal of the vibration sensor.

[0129] Example Ex34: An aerosol generating device, wherein, in any one of the above-described examples, it further comprises a sprayer for dispersing particles or droplets of an aerosol-forming substrate into an air stream to form, for example, an inhalable aerosol.

[0130] Example Ex35: An aerosol generating device comprising, in any one of Examples Ex1 to Ex33, an electric heater for heating an aerosol-forming substrate.

[0131] Example Ex36: An aerosol generating device in Example Ex35, wherein the electric heater comprises an inductive heater or a resistive heater.

[0132] Example Ex37: The aerosol generating device according to Example Ex35, wherein the inductive heater comprises an inductor, in particular an induction coil, for generating an alternating magnetic field within the device, in particular within the receiving cavity of the device.

[0133] An aerosol generating system comprising an aerosol generating device according to any one of the embodiments and an aerosol generating article comprising an aerosol forming substrate, wherein at least a portion of the article is removablely accommodated or removablely accommodated within the device, particularly within a receiving cavity of the device. Brief explanation of the drawing

[0134] Embodiments of the present invention will be further described with reference to the accompanying drawings. FIG. 1 schematically illustrates a first exemplary embodiment of an aerosol generating device according to the present invention in a cross-sectional view; FIG. 2 shows details of an aerosol generating device according to FIG. 1; FIG. 3 shows additional details of the sound generating member of the aerosol generating device according to FIG. 1; FIG. 4 shows details of a sound generating member of an aerosol generating device according to FIG. 1; and FIG. 5 schematically shows a cross-sectional view of a second exemplary embodiment of an aerosol generating device according to the present invention. Specific details for implementing the invention

[0135] Fig. 1 The figure schematically illustrates a first exemplary embodiment of an aerosol generating system (1) according to the present invention. The system (1) comprises two main components: an electrically operated aerosol generating device (100) and an aerosol generating article (190) for use with the device (100). The device (100) is configured to heat an aerosol forming substrate (191) contained within the article (190). The substrate (191) can release a volatile compound that forms an inhalable aerosol when heated and released into an airflow passing through the system (1) during use.

[0136] The aerosol generating device (100) has an elongated shape and includes a distal portion (101) and a proximal portion (102). Within the proximal portion (102), the device (100) includes a receiving cavity (120) formed in the device housing (110) to accommodate at least a portion of an aerosol generating article (190). Within the distal portion (101), the device (100) includes an electrical circuit (151) comprising an electronic device, in particular a power source (150) and a controller (152), for supplying power to the aerosol generating device (100) and controlling the operation of the aerosol generating device.

[0137] The article (190) has a rod shape similar to the shape of a conventional cigarette. In this embodiment, the article (190) comprises four elements arranged in succession in coaxial alignment: a base element (192), a support element (193), an aerosol cooling element (194), and a filter plug (195). The base element (192) is arranged at the distal end of the article (190) and comprises an aerosol-forming base (191) to be heated. The aerosol-forming base (191) may comprise, for example, a coiled sheet of homogenized tobacco material containing glycerin as an aerosol-forming agent. The support element (193) comprises a hollow core forming a central air passage. The cooling element (194) has a large surface area and low suction resistance, which allows the aerosol formed by the volatile compound released from the base element (192) to be cooled before being transported to the proximal end of the article (190). The filter element (195) functions as a mouthpiece and may include, for example, cellulose acetate fibers for filtering aerosols. The four elements (192, 193, 194, and 195) are substantially cylindrical in shape and have approximately the same diameter. The elements are surrounded by an outer wrapper (196) made of cigarette paper, for example, to form a cylindrical rod. The outer wrapper (196) may be wrapped around the aforementioned elements such that the free ends of the wrapper overlap each other. The wrapper may further include an adhesive to bond the overlapping free ends of the wrapper together.

[0138] To heat the substrate (191) within the article (190), the aerosol generating device (100) according to the present invention includes an induction heating device. The induction heating device includes an induction coil (140) for generating an alternating, particularly high-frequency magnetic field within the receiving cavity (120). Preferably, the high-frequency magnetic field 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). In this embodiment, the induction coil (140) is a helical coil arranged within the device housing (110). The coil (140) is aligned coaxially with the longitudinal axis of the receiving cavity (120) and circumferentially surrounds a portion of the cylindrical cavity (120). The alternating magnetic field is used to inductively heat a susceptor (141) arranged within an aerosol-forming substrate (191) of an article (190) so as to experience a magnetic field generated by an induction coil (140) when the article (190) is received within a cavity (120), for example. In this embodiment, the susceptor (140) is a susceptor blade arranged within a substrate element (192) along the longitudinal axis of the article (190) so as to be in direct physical contact with, for example, the aerosol-forming substrate (191).

[0139] Accordingly, when the induction heating device is operated, high-frequency alternating current passes through the induction coil (140) to generate an alternating magnetic field within the cavity (120). Depending on the magnetic and electrical properties of the susceptor material, the alternating magnetic field induces at least one of eddy current or hysteresis loss in the susceptor (141). Consequently, the susceptor (141) is heated until it reaches a temperature sufficient to vaporize a volatile compound from the aerosol-forming substrate (191). The vaporized compound is released and entrained into an airflow passing through the article (190) from the substrate element (192) at the distal end of the article (190) toward the filter element (195) through the support element (193) and the cooling element (194). In this manner, the vaporized material is cooled to form an inhalable aerosol, which can subsequently escape from the article (190) through a filter element (195) at the proximal end of the article (190).

[0140] According to the present invention, an aerosol generating device (100) includes an air path (180) for providing an airflow through a system (1), wherein a material of an aerosol forming substrate may be released to form an inhalable aerosol. As indicated by the curved arrow (180) in FIG. 1, the aerosol generating article system (1) of the present embodiment includes an air path starting from an insertion opening (122) at the proximal end of a receiving cavity (120), which is used to insert an aerosol generating article (190) into a cavity (120). Thus, the insertion opening (122) also serves as an air inlet for the device (100). The air path (180) extends further along the inner surface of the receiving cavity (120) toward the distal end surface (bottom) of the receiving cavity (120). The latter part of the air path is formed between the inner surface of the receiving cavity (120) and the outer circumference of the aerosol generating article (190) when inserted into the cavity (120). As previously described, the latter part of the air path may be provided, for example, by a gap (free space) between protrusions (not shown) that are part of the inner surface of the receiving cavity (120) and are used to provide clamping retention of the article (190) within the cavity (120). At the distal end surface (bottom) of the receiving cavity (120), the air path is redirected proximally—as illustrated by the curved arrow (181) in FIG. 1—to enter, for example, into the substrate element (192) of the aerosol generating article (190). From this, the air path is further extended through various elements (192, 193, 194 and 195) of the article (190), where it finally leaves the system (1) as described above in relation to the aerosol-generating article (190).

[0141] Accordingly, when the user puffs, that is, when negative pressure is applied to the filter element (195) of the article (190) contained within the cavity (120), for example, air is drawn into the receiving cavity (120) from the rim of the insertion opening (122) and further drawn into the lower portion along the airflow passage from the distal end of the receiving cavity (120). The airflow enters the aerosol generating article (190) through the substrate element (192), further passes through the support element (193), the aerosol cooling element (194), and the filter element (195), where the airflow finally exits the article (190). When the induction heating device is turned on, the vaporized material from the aerosol-forming substrate is entrained into the airflow through the substrate element (192) and subsequently cooled in an additional manner through the support element (193), the aerosol cooling element (194), and the filter element (195) to form, for example, an aerosol.

[0142] In order to enable proper re-induction of airflow into an aerosol generating article (190) at the lower portion of the receiving cavity (120), the aerosol generating device (100) may include one or more end stops (not shown) that can be arranged at the distal end of the receiving cavity (130) to limit the insertion depth of the article (190) into the cavity (120), and thus prevent the article (190) from coming into contact with the distal end surface (123) of the receiving cavity (120).

[0143] As further mentioned above, proper puff detection is important to ensure accurate control of the heating process. To this end, the aerosol generating device (100) according to the present embodiment includes a puff detector comprising a vibration sensor (170) for detecting sound caused by airflow through the air path (180, 181) of the device (100), which in turn indicates that a user is puffing. In the present embodiment, the vibration sensor (170) is a microphone, for example, a moving coil microphone. As can be seen in FIG. 1, the vibration sensor (170) is arranged outside the fluid-separated receiving cavity (120) from the air path (180, 181) passing through the device (100). Due to the separated arrangement, the vibration sensor (170) is not exposed to conditions of the air path, such as temperature and moisture. In particular, the vibration sensor (170) is insulated from suspended particles or droplets resulting from aerosol formation and is therefore protected from any deposits. In this embodiment, the vibration sensor (170) is arranged in a compartment (125) within a distal portion (101) that also includes an electrical circuit (151) comprising a power source (150) and a controller (152) as described above. The compartment (125) is fluidly separated from the receiving cavity (120) within the proximal portion (102) of the device (100).

[0144] To enhance the sound effect used to identify a user's puff and to indicate the airflow through the device (100), the aerosol generating device (100) further includes a sound generating member (160). The sound generating member (160) is arranged in fluid communication with the aforementioned air path (180, 181) and is configured to generate a sound caused by the airflow passing through the sound generating member (160) when the user puffs. In this embodiment, the sound generating member (160) includes a sound generating displacement structure, which is configured to displace the airflow (181) at least partially when passing through the sound generating displacement structure.

[0145] Fig. 2 , Fig. 3 and Fig. 4 This shows details of a sound-generating displacement structure (161) implemented in the device according to FIG. 1. In this embodiment, the sound-generating displacement structure (161) comprises a one-dimensional array of ridges (162) arranged in a periodic pattern at the distal end of the receiving cavity (120) (Figs. 2 through 4 are not made to actual size). Grooves (163) are formed between each of two adjacent ridges (106). The cross-sectional shape of the ridges (162) is substantially triangular so that each ridge (162) has a sharp edge at its top.

[0146] Accordingly, when the airflow (182) passes through the sound-generating displacement structure (161), the airflow (182) is partially displaced due to collision with the ridge (162) of the displacement structure (161), so that part of the airflow (180) becomes turbulent, as shown in FIG. 2. As a result, part of the kinetic energy of the airflow, i.e., dynamic pressure, is converted into static pressure, resulting in a plurality of alternating high-pressure and low-pressure regions (185, 186), as shown in FIG. 3. The alternating pattern of adiabatic compression and release in the airflow (180) generates sound waves, i.e., sound, that propagate through the device (100). Sound waves originating from the sound-generating displacement member (161) are propagated—among other things—through the wall member (111) that fluidly separates the receiving cavity (120) from the partition (125). The sound waves propagate further through the air within the compartment (125) until they reach the vibration sensor (170). Here, the sound waves (sound) are detected, indicating the presence of airflow through the device (100), which consequently indicates that the user is taking puffing. Thus, the sound-generating displacement structure (161) is part of the wall member, i.e., the wall member (111), and defines at least a portion of the air path passing through the device (100).

[0147] In addition to the vibration sensor (170), the puff detector further includes an electrical circuit operably coupled to the vibration sensor (170) and configured to convert the output signal of the vibration center (170) into a signal indicating the presence of airflow within the receiving cavity (120). The electrical circuit may further include one or more electronic filters for filtering the output signal of the vibration sensor. Advantageously, the filtering can reduce different types of noise, particularly parasitic noise detected by the vibration sensor (170). The electrical circuit of the puff detector may be an integral part of the electrical circuit (151) including a controller (152). Based on the signal indicating the presence of airflow through the device (100), the controller (152) may adjust the control of the heating process to maintain the heating temperature of the material (191) within the article (190) at a specific level when the user puffs.

[0148] As illustrated in FIG. 4, the length (164) of the periodic pattern of the sound-generating displacement structure (161) is selected to generate sound in a specific frequency range, for example, depending on the speed of the airflow (182). For example, if the speed of the airflow (182) in the sound-generating displacement structure (161) is about 10 m / s and the displacement structure (161) includes ridges (162) that appear at 0.25 mm each, the sound has a frequency of about 40 kilohertz (kHz). This frequency is outside the range of frequencies that humans can hear, and is also outside the range of frequencies that many animals, especially pets, for example, dogs or cats, can hear.

[0149] Fig. 5Figure 5 illustrates a second embodiment of an aerosol generating device (100) according to the present invention. In this embodiment, a vibration sensor (270) is attached to a wall member (211) that fluidly separates the receiving cavity (220) from the partition (225). That is, the vibration sensor (270) is arranged on the side of the wall member (211) facing the side of the wall member (211) that defines at least a portion of the air path through the device (200) and also forms or at least supports the sound generating displacement structure (261). Consequently, the vibration sensor (270) is coupled closer to, and particularly directly to, the sound generating displacement structure (261), i.e., the source of sound. Advantageously, this configuration improves the detectability of sound propagating through the device (100). Apart from this, the embodiment according to Figure 5 is identical to the first embodiment shown in Figures 1 through 3. Therefore, identical or similar features are displayed with the same reference number, increasing by 100.

[0150] For the purposes of this description and the appended claims, all numbers expressing amounts, quantities, percentages, etc., unless otherwise indicated, shall be understood as modified by the term “about” in all cases. Additionally, all ranges include the disclosed maximum and minimum points and include any intermediate ranges that may or may not be specifically enumerated herein. Accordingly, in this context, the number A is understood as A ± 5% of A.

Claims

Claim 1 An electrically operated aerosol generating device for generating an aerosol, wherein the device comprises: - a receiving cavity for removably receiving at least a portion of an aerosol generating article comprising an aerosol forming material or an aerosol generating article comprising an aerosol forming material; - an air path extending through the device and configured to support an airflow within the device; - a sound generating member arranged in fluid communication with the air path and configured to generate a sound caused by an airflow passing through a sound generating member when a user puffs the device, the sound generating member positioned at the distal end of the receiving cavity; and - a puff detector comprising a vibration sensor, wherein the vibration sensor is fluidly separated from the air path and configured to detect sound propagating from the sound generating member to the vibration sensor. Claim 2 An aerosol generating device according to claim 1, wherein the sound generating member comprises a sound generating displacement structure for displacing the airflow at least partially when passing through the sound generating displacement structure. Claim 3 An aerosol generating device according to paragraph 2, wherein the sound generating displacement structure comprises at least one of one or more grooves, one or more ridges, one or more dimples, or one or more protrusions. Claim 4 An aerosol generating device according to paragraph 3, wherein the one or more groove length extension portions, or the one or more ridge length extension portions, or the one or more groove length extension portions and the one or more ridge length extension portions are perpendicular to the direction of the airflow passing through the sound generating member when the device is used. Claim 5 An aerosol generating device according to paragraph 3, wherein the one or more grooves, or the one or more ridges, or the one or more grooves and the one or more ridges comprise one of a triangular shape, a sinusoidal shape, or a rectangular shape. Claim 6 An aerosol generating device according to paragraph 3, wherein at least one of the height of the ridge or the depth of the groove is variable or increases along the sound generating displacement structure in the direction of the airflow passing through the sound generating member when the device is used. Claim 7 In claim 6, the sound-generating displacement structure is part of a wall member defining at least a portion of the air path through the device, an aerosol generating device. Claim 8 In paragraph 6, the sound-generating displacement structure comprises an aerosol generating device having a periodic pattern. Claim 9 In claim 8, the aerosol generating device, wherein the periodic pattern has a periodic length in the range of 0.1 mm to 2 mm. Claim 10 An aerosol generating device according to claim 1, wherein the sound generating member comprises at least one airflow-driven vibrating element configured to periodically block the airflow passing through the vibrating element. Claim 11 An aerosol generating device according to claim 10, wherein at least one vibrating element comprises a reed or a lamellar or a pair of reeds or a pair of lamellas. Claim 12 An aerosol generating device according to claim 1, wherein the air path and the sound generating member are configured such that the sound generated when the device is used is in a frequency range greater than 15 kHz. Claim 13 An aerosol generating device according to claim 1, wherein the vibration sensor comprises a microphone, an accelerometer, a strain sensor, or a piezoelectric transducer or a magnetoacoustic transducer. Claim 14 An aerosol generating device according to claim 1, wherein the vibration sensor is arranged on the side of a wall member facing the side of a wall member that defines at least a portion of the air path through the device. Claim 15 In claim 1, the sound generating member is located on the distal end surface of the receiving cavity, an aerosol generating device.

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