RU2823739C1 - Aerosol-generating electric device containing air flow detector in device - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: invention relates to an electrical aerosol generating device for generating an aerosol. Device comprises an air path passing through the device and configured to maintain an air flow in the device. Device additionally comprises a sound generating element arranged in fluid communication with the air path and configured to generate sound caused by the passage of air flow through the sound generating element when the device is used when the user puffs. Device additionally contains a puff detector containing a vibration sensor. Vibration sensor is fluidly separated from the air path and is configured to detect sound propagating from the sound generating element to the vibration sensor. Present invention further relates to an aerosol-generating system comprising such a device, and an aerosol-generating article comprising an aerosol-forming substrate.

EFFECT: improving the means for detecting the flow of air passing through the device, which indicates the user is taking a puff.

15 cl, 5 dwg

Description

The present invention relates to an electrical aerosol generating device for generating an aerosol, in particular for generating an aerosol by releasing a substance of an aerosol-forming substrate into an air flow, wherein the device comprises a means for detecting an air flow in the device. The present invention further relates to an aerosol generating system comprising such a device and to an aerosol generating article comprising an aerosol-forming substrate.

Electrically powered aerosol generating devices used to generate inhalable aerosols by releasing an aerosol-forming substrate substance into an air stream are well known in the art. For example, such devices may comprise an electrical heater for heating an aerosol-forming substrate capable of releasing volatile compounds that form an inhalable aerosol when heated. As another example, such devices may comprise a nebulizer for spraying particles or droplets of an aerosol-forming substrate into an air stream so as to form an inhalable aerosol.

In order for the user experience to be as uniform as possible, the release of the substance from the aerosol-forming substrate must be maintained at a certain level when the user inhales. However, the release of the substance may vary during consumption, in particular due to the air flow drawn through the system during the user's inhale. For this reason, proper puff detection is important for precise control of the release of the substance. Puff detection can be implemented, for example, by measuring the pressure drop in the air flow passing through the device when the user inhales. For this purpose, many devices include a pressure sensor in direct fluid communication with the air path passing through the device to directly detect the air flow indicating that the user is inhaling. However, with such an arrangement, the sensor is directly exposed to the conditions inside the air path, such as the heat and moisture caused by the formation of the aerosol. This can negatively affect proper air flow detection and can lead to inaccurate or even inoperative puff detection.

It would therefore be desirable to provide an electrical aerosol generating device comprising a puff detection means that utilizes the advantages of the prior art while eliminating the disadvantages thereof. In particular, it would be desirable to have an electrical aerosol generating device comprising an improved means for detecting an air flow passing through the device that indicates a puff by the user.

According to the present invention, an electrical aerosol generating device is provided for generating an aerosol, in particular an electrical aerosol generating device for generating an aerosol by releasing an aerosol-forming substrate substance into an air flow. The device comprises an air path passing through the device and configured to maintain an air flow in the device. The device further comprises a sound generating element located in fluid communication with the air path and configured to generate a sound caused by the air flow passing through the sound generating element when using the device, when the user takes a puff. In addition, the device comprises a puff detector comprising a vibration sensor. The vibration sensor is separated by a fluid medium, at least inside the device, from the air path and is configured to detect a sound propagating from the sound generating element to the vibration sensor. Accordingly, detecting the sound propagating from the sound generating element to the vibration sensor can make it possible to detect an air flow passing through the device that indicates a puff by the user.

According to the present invention, it has been recognized that the air flow, in particular changes in the air flow indicating that the user is taking a puff, can be reliably detected by using the air flow to generate air vibrations (sound) or vibrations of at least a part of the device that are propagated and can thus be detected by the vibration sensor. Due to the possibility of remotely detecting the propagated vibrations, the vibration sensor can be located separately in the fluid medium from the air path in the device. Advantageously, the separate fluid location of the vibration sensor makes the air flow and the detection of the puff less subject to errors and, thus, more reliable. In addition, it has been recognized that the use of a sound generating element can act as an amplifier of the air flow passing through the air path by generating vibrations transmitted to the remote vibration sensor.

In the context of this document, the term "sound" or "propagating vibrations" generally refers to a mechanical acoustic wave propagating through a gaseous, liquid or solid medium, in particular air or structural components (solid matter) of an aerosol generating device. The term "acoustic wave" refers to the type of energy propagation by adiabatic compression and compression reduction of the medium (air or solid matter of the device, respectively).

The terms "acoustic waves" or "sound" may refer to acoustic waves or sound that can be perceived/heard by humans using their auditory perception, in particular hearing. Frequencies that can be heard by humans typically range from 20 Hertz (Hz) to 20,000 Hertz (Hz). Similarly, the terms "acoustic waves" or "sound" may refer to acoustic waves or sound in a frequency range outside the frequency spectrum that humans can hear, in particular in the frequency range above 20,000 Hertz (Hz) or in the frequency range below 20 Hertz (Hz). Accordingly, the terms "acoustic waves" or "sound" may refer to ultrasonic waves or sound or infrasonic waves or sound.

In general, the sound generating element may be any mechanical element suitable for generating sound by an air flow passing through a vibrating sound generating element. In this regard, the sound generating element may also be called an "air flow driven sound generating element".

In order to generate a sound, the sound-generating element may comprise a sound-generating displacing structure, which is designed to partially displace an air flow as it passes through the sound-generating displacing structure. As in wind instruments using air displacement, such as trumpets, whistles and flutes, the air flow passing through the sound-generating displacing structure is divided and modified by the displacing structure in such a way as to create vibrations in the air flow, i.e. adiabatic compressions and reductions of the air flow compression. Typically, the sound-generating displacing structure may comprise one or more edges, in particular sharp edges, which the air flow encounters as it passes through the sound-generating displacing structure.

Preferably, the sound-generating displacing structure comprises at least one of the following: one or more grooves or one or more ribs, one or more recesses or one or more projections. When air passes along one or more grooves, recesses, projections or ribs, respectively, the laminar air flow contacting the one or more grooves, recesses, projections or ribs is transformed into a turbulent air flow due to collisions with one or more grooves or ribs, respectively. Accordingly, part of the kinetic energy of the air flow, i.e. the dynamic pressure, is transformed into static pressure. If the sound-generating displacing structure comprises several grooves or ribs, respectively, the partial displacement of the air flow creates several alternating high and low pressure regions in the air flow, which create vibrations in the air flow, i.e. the sound.

In general, the frequency and amplitude of the sound depend on the shape, height or depth and periodicity of the grooves, recesses, projections or ribs, respectively. In addition, the frequency and amplitude of the sound depend on the speed of the air flow passing along the vibrating displacement structure generating the sound. Accordingly, the shape, height or depth of the grooves, recesses, projections or ribs and, in the case of several grooves, recesses, projections or ribs, the periodicity of the grooves, recesses, projections or ribs can be designed in such a way as to selectively generate vibrations having a certain frequency (frequency spectrum) and amplitude.

The one or more grooves, or one or more ribs, or one or more grooves and one or more ribs may have any shape suitable for partially displacing the air flow. Preferably, the one or more grooves, or one or more ribs, or one or more grooves and one or more ribs may have one of the following shapes: a triangular shape, a curved shape, in particular a sinusoidal shape, or a rectangular shape. In the context of the present document, the shape of one or more grooves or ribs, respectively, refers to the shape of the section of the one or more grooves or ribs when viewed in a section perpendicular to the longitudinal extension of the one or more grooves or ribs, respectively.

In general, several grooves or ribs may be uniformly or non-uniformly distributed along the sound-generating displacing structure. Preferably, the sound-generating displacing structure comprises a periodic pattern. In other words, the grooves or ribs or both the grooves and the ribs are arranged in a periodic pattern having a constant distance between each pair of adjacent grooves or ribs, respectively. The periodic pattern is advantageous for generating vibrations having a certain frequency spectrum, in particular a frequency spectrum with a narrow range.

Depending on the frequency of the generated sound, the periodic pattern may have a periodicity in the range from 0.5 ribs or grooves per millimeter to 10 ribs or grooves per millimeter, in particular from 1 rib or groove per millimeter to 5 ribs or grooves per millimeter, preferably from 2 ribs or grooves per millimeter to 4 ribs or grooves per millimeter. In other words, the periodic pattern may have a period length in the range from 0.1 millimeter to 2 millimeters, in particular from 0.2 millimeters to 1 millimeter, preferably from 0.25 millimeters to 0.5 millimeters. Accordingly, the sound-generating displacing structure may comprise several ribs or grooves, or both several ribs and several grooves, wherein the distance between each pair of adjacent grooves or ribs is in the range from 0.1 millimeters to 2 millimeters, in particular from 0.2 millimeters to 1 millimeter, preferably from 0.25 millimeters to 0.5 millimeters.

For example, if the periodic pattern of a sound-generating displacement structure has a period length of 0.25 mm and the air flow velocity through the sound-generating displacement structure is 10 meters per second, then a sound with a frequency of about 40 kilohertz (kHz) can be generated.

The periodic pattern may be a linear periodic pattern. The periodic pattern may be one-dimensional, such as a sequence of several parallel grooves or ribs. In other words, the pattern contains periodicity in only one direction. The periodic pattern may be multi-dimensional, in particular a two-dimensional pattern. In other words, the pattern contains periodicities in more than one direction, in particular in two directions. For example, the pattern may contain a first periodicity in a first direction and a second periodicity in a second direction. The first direction and the second direction may be transverse, in particular perpendicular to each other. As an example, the periodic pattern may contain a first sequence of several parallel first grooves or first ribs having a first periodicity in the first direction, and a second sequence of several parallel second grooves or second ribs having a second periodicity in the second direction. In particular, such a periodic pattern may be a cross pattern or a mesh pattern.

The periodic circuit may be a nonlinear periodic circuit. For example, the periodic circuit may contain several curved, in particular annular grooves or curved, in particular annular ribs. The periodic circuit may contain a circuit in the form of concentric rings formed by several annular grooves or several annular ribs. The circuit in the form of rings or the shape of the rings may be circular, elliptical, oval, rectangular, square or polygonal. From the point of view of symmetry, the circuit in the form of periodic rings may be advantageous in relation to the location of the displacing structure generating the sound on the far end surface of the cylindrical receiving cavity.

As another example, the periodic pattern may comprise a spiral pattern formed by a spiral groove or a spiral rib.

As another example, a periodic circuit may comprise a honeycomb pattern comprising a plurality of grooves or ridges forming the outline of the honeycomb pattern.

To improve sound generation, the lengthwise extension of at least one or more grooves or one or more ribs may be transverse, in particular perpendicular to the direction of air flow passing through the sound generating element when using the device.

At least one of the height of the ribs or the depth of the grooves varies, may be constant along the sound-generating displacing structure in the direction of the air flow passing through the sound-generating element when using the device. Alternatively, at least one of the height of the ribs or the depth of the grooves varies, may differ, in particular increases along the sound-generating displacing structure in the direction of the air flow passing through the sound-generating element when using the device. This may allow the sound generation to be adapted to the geometric shape and dimensions of the air path, for example, to ensure a certain resistance to draw (RTD).

Preferably, the sound-generating element, in particular the sound-generating displacing structure, is part of a wall-shaped element that forms at least part of the path for air passing through the device. This can advantageously simplify the manufacture and assembly of the device. In particular, the presence of the sound-generating displacing structure, made integral with the wall-shaped element of the device, ensures a compact design of the device. For example, the sound-generating displacing structure can comprise one or more grooves or one or more ribs, or one or more grooves and one or more ribs formed in the wall-shaped element of the device that forms at least part of the path for air passing through the device.

Similarly, the sound-generating element, in particular the sound-generating displacing structure, may be a separate part or element separate from the wall element forming at least part of the path for air passing through the device, in particular a separate part or element connected to the wall element.

The sound-generating displacing structure is preferably a rigid structure. Thus, neither the sound-generating displacing structure as a whole nor any structural components of the sound-generating displacing structure deviate from the center of mass. However, this does not exclude the possibility that sound may propagate through the sound-generating displacing structure.

As an alternative or in addition to the sound-generating displacement structure, the sound-generating element may comprise at least one air-driven vibration element for periodically interrupting the air flow passing through the vibration element. As in wind instruments using air flow interruption, in particular reed wind instruments such as oboes or clarinets, the air flow is directed onto a flexible vibration element, such as a thin plate or a pair of thin plates, which causes the vibration element to vibrate. Due to the air-driven vibrations of the flexible vibration element, the air flow passing through the vibration element is periodically interrupted, which sets the air in motion, thereby creating a sound.

Accordingly, at least one vibrating element may comprise a thin plate or tongue or a pair of tongues or a pair of thin plates.

In a similar manner, at least one vibrating element may comprise a limited movable element for periodically interrupting the air flow passing through the vibrating element. In order to limit the free movement of the movable element, it may be located in a fence, like a ball in a whistle with a ball. In a similar manner, the movable element may be limited by attaching the movable element to one end of the elastic element, while the other end of the elastic element is fixedly attached to the device.

It is of course possible for the sound generating element to contain several vibrating elements, such as several thin plates or tongues. The presence of several vibrating elements advantageously improves the amplitude of the generated sound, which in turn facilitates the propagation of the sound to the vibration sensor.

As mentioned above, the amplitude and frequency/frequency spectrum of the generated sound can be affected by the dimensions and configuration of the air path and the sound generating element. In order to make the generated sound inaudible to the user of the device, in particular in order to avoid unwanted noise exposure, the generated sound is preferably outside the frequency spectrum that a person can hear, even more preferably outside the frequency spectrum that many animals can hear, in particular pets such as dogs or cats. Accordingly, the air path and the sound generating element can be designed so that the sound generated when using the device is in the frequency range above 15 kilohertz (kHz), preferably above 20 kilohertz (kHz), more preferably above kilohertz (kHz).

In order for the vibration sensor to be separated by a fluid medium - at least within the device - from the air path passing through the device, the vibration sensor can be arranged in a compartment of the device which is separated by a fluid medium - at least within the device - from the air path passing through the device. As a result, the vibration sensor is not in direct fluid communication with the air path, in particular is not in direct contact with any fluids (air, aerosol, aerosol particles) passing through the air path. This does not exclude the vibration sensor being in indirect fluid communication with the air path passing through the device, for example by direct fluid communication with the ambient air outside the device, which in turn can be in direct fluid communication with the air path passing through the device, for example by an air inlet or an air outlet in the device. In this configuration, the vibration sensor is still sufficiently isolated from any fluids (air, aerosol, aerosol particles) passing along the air path.

Accordingly, a compartment of a device that is fluidly separated from an air path may be in fluid communication with a medium surrounding the device, in particular with ambient air outside the device.

Alternatively, the compartment of the device, fluidly separated from the path for air passing through the device, may also be hermetically fluidly separated from the environment surrounding the device, in particular from the ambient air outside the device.

Although the vibration sensor is separated by a fluid medium from the air path passing through the device, the sound generated at the sound generating element can easily propagate from the sound generating element to the vibration sensor through different media. In other words, the sound can propagate through the air inside the device, through the ambient air outside the device and through a solid substance of the device, such as a wall element of the device, for example through a wall element forming at least a part of the air path or a wall element separating the above-mentioned compartment from the air path. Depending on the properties associated with the propagation of sound of the different media and depending on the physical design and dimensions of the device, the sound can propagate from the sound generating element directly to the vibration sensor. Alternatively or additionally, the sound can propagate from the sound generating element to the vibration sensor through the medium surrounding the device. In other words, the sound can at least partially leave the device and re-enter the device before reaching the vibration sensor.

The vibration sensor may be located inside the device in such a way that the sound is transmitted to the vibration sensor from the air surrounding at least part of the vibration sensor. Accordingly, the vibration sensor may be located inside the device in such a way that it is at least partially surrounded by a fluid medium, in particular air.

In a similar manner, the vibration sensor may be arranged inside the device in such a way that the transmission of sound to the vibration sensor occurs from the solid substance of the device component with which the vibration sensor is in contact. For example, the vibration sensor may be arranged at a wall element of the device, such as a wall element of the device that separates the sensor from the air path in a fluid medium. In particular, the vibration sensor may be arranged at the wall element, in particular on the side of the wall element opposite to the side of the wall element that forms at least part of the air path passing through the device.

The vibration sensor may contain an electroacoustic transducer. The electroacoustic transducer is a device designed to convert sound energy into electrical energy. Depending on the nature of the sound transmission to the vibration sensor, the vibration sensor may contain, for example, a microphone, an accelerometer, a strain gauge, or a piezoelectric acoustic transducer or a magnetic acoustic transducer.

A piezoelectric acoustic transducer is a device that uses the piezoelectric effect to detect sound by measuring changes in pressure, acceleration, mechanical stress, or force caused by sound and converting the measured change into an electrical signal. Similarly, a magnetic acoustic transducer is a device that uses electromagnetic induction to detect sound by measuring changes in pressure, acceleration, mechanical stress, or force caused by sound and converting the measured change into an electrical signal.

Similarly, accelerometers or strain gauges can be used to measure the movement and vibration of a structure subjected to a dynamic load caused by sound attached to these types of sensors. A strain gauge is a sensor whose resistance changes depending on the applied force. It converts force, pressure, mechanical stress into a change in electrical resistance that can be measured. An accelerometer measures the proper acceleration of a sensing element, such as a membrane, which corresponds to variations in air pressure or vibrations/sound in a solid body to which the sensing element is mechanically connected.

The microphone may be an electromagnetic microphone (also known as a dynamic microphone or moving coil microphone), which uses magnetic induction to convert sound energy into electrical energy. Electromagnetic microphones are reliable, relatively inexpensive, and resistant to moisture. Electromagnetic microphones use the same dynamic principle as a loudspeaker, only in reverse. A small moving induction coil, located in the magnetic field of a permanent magnet, is attached to a diaphragm. When sound hits the microphone, the sound wave causes the diaphragm to move. When the diaphragm vibrates, the coil moves in the magnetic field, generating a changing current through electromagnetic induction. This type of microphone may also be called a magnetic acoustic transducer, or may be a specific example of a magnetic acoustic transducer.

The microphone may be an electrostatic microphone, such as a condenser microphone, an electret microphone, or a piezoelectric microphone. The latter may also be called a piezoelectric acoustic transducer, or may be a specific example of a piezoelectric acoustic transducer, which is described in detail below.

The microphone may be a fiber optic microphone. A fiber optic microphone converts acoustic waves into electrical signals by sensing changes in the intensity of light passing through an optical fiber. During operation, light from a light source travels through the optical fiber and illuminates the surface of a reflective diaphragm. Sound vibrations of the diaphragm modulate the intensity of light reflected from the diaphragm in a certain direction. The modulated light is transmitted through a second optical fiber to a photodetector, which converts the light with the modulated intensity into an electrical signal. Fiber optic microphones have a large dynamic and frequency range. Advantageously, fiber optic microphones do not create interference for electric, magnetic or electrostatic fields. Therefore, fiber optic microphones are ideal for use in electrical aerosol-generating devices, in particular inductively heated aerosol-generating devices.

The device may comprise a device housing that comprises an air path passing through the device. The device housing may be configured to receive an aerosol-forming substrate containing a substance intended to be released into an air stream passing through the air path.

In general, the aerosol generating device may comprise at least one air inlet, through which air may enter the air path passing through the device. Thus, the air inlet may be considered the starting point of the air path passing through the device. Similarly, the aerosol generating device may comprise at least one air outlet, through which air may exit the air path passing through the device. Thus, the air outlet may be considered the ending point of the air path passing through the device. The air outlet may be provided, for example, in the mouthpiece portion of the device.

The aerosol generating device may comprise a receiving cavity for retrievably receiving an aerosol generating substrate or at least a portion of an aerosol generating article containing the substrate.

The receiving cavity may comprise an insertion opening through which the aerosol-forming substrate or the aerosol-generating article can be inserted into the receiving cavity. In the context of this document, the direction in which the aerosol-forming substrate or the aerosol-generating article is inserted is referred to as the insertion direction. Preferably, the insertion direction corresponds to the extension of the length axis, in particular the central axis of the receiving cavity.

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, in particular for being contained in the user's mouth. Therefore, during use of the device, the insertion opening may be close to the user's mouth.

Accordingly, in the context of this document, sections that are close to the insertion opening or close to the user's mouth when using the device, respectively, are typically referred to as "near." Sections that are further away are typically referred to as "distal."

According to these conditions, the receiving cavity can be located or placed in the proximal part of the aerosol generating device. The insertion opening can be located or placed at the proximal end of the aerosol generating device, in particular, at the proximal end of the receiving cavity.

The air path passing through the device may at least partially pass through a wall forming at least a part of the receiving cavity. Such configurations are described, for example, in document WO 2013/102609 A2.

In addition or alternatively, the air path passing through the device may at least partially extend along the inner surface of the receiving cavity. For this purpose, the receiving cavity may comprise several projections extending into the inner space of the receiving cavity. Preferably, several projections are arranged at a distance from each other such that the air path or at least part of the air path passing through the device is formed between adjacent projections, i.e. is formed by gaps (free space) between adjacent projections. In addition, several projections may be configured to contact at least part of the aerosol-forming substrate or the aerosol-generating article to retain the substrate or article in the receiving cavity. Examples of such a configuration are described in document WO 2018/050735 A1.

In this configuration, the air inlet of the device is preferably implemented in an insertion opening in the receiving cavity used to insert a substrate or an article into the cavity. When the substrate or the article is inserted into the cavity, air can be drawn into the receiving cavity at the edge of the insertion opening and further through a portion of the air path formed between the inner surface of the receiving cavity and the outer circumference of the aerosol-forming substrate or the aerosol-generating article.

Preferably, a portion of the air path passes through an aerosol-forming substrate or an aerosol-generating article. From there, the air path may directly pass into the user's mouth. Alternatively, the air path may pass through the mouthpiece portion of the device, where air exits the device through an air outlet in the mouthpiece portion.

The aerosol generating device may comprise one or more end stops located inside the receiving cavity, in particular at the distal end of the receiving cavity. The one or more end stops are preferably configured to limit the depth of introduction of the aerosol-forming substrate or the 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 the aerosol-generating article from adjoining the distal end surface of the receiving cavity opposite the opening for introduction in the receiving cavity located at the proximal end of the receiving cavity. Thus, the one or more end stops advantageously provide free space inside the distal part of the receiving cavity, ensuring an unimpeded air flow between the distal end of the receiving cavity and the distal end of the aerosol-generating article, when the substrate or the article is placed in the receiving cavity. One or more end stops may comprise a contact surface to which an aerosol generating article, in particular a distal end of the aerosol generating article, may abut when the article is positioned in the receiving cavity.

Preferably, the aerosol generating device may comprise several separate end stops, for example three end stops, located inside the receiving cavity, in particular at the distal end of the receiving cavity.

Several end stops can be arranged symmetrically relative to the length axis, in particular the central axis of the receiving cavity. Preferably, several end stops can be arranged at an equal distance from the length axis, in particular the central axis of the receiving cavity. As described above, this ensures an unimpeded air flow around the end stops and the product placed in the receiving cavity.

In general, 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 the aerosol-generating article placed therein. Preferably, the receiving cavity may have a substantially cylindrical shape or a tapering shape, for example, a substantially conical shape or a substantially truncated conical shape.

Similarly, the receiving cavity may have any suitable cross-section when viewed in a plane perpendicular to the length axis of the receiving cavity or perpendicular to the direction of insertion of the article. In particular, the cross-section of the receiving cavity may correspond to the shape of the aerosol-generating article placed therein. Preferably, the receiving cavity has a substantially circular cross-section. Alternatively, the receiving cavity may have a substantially elliptical cross-section, or a substantially oval cross-section, or a substantially square cross-section, or a substantially rectangular cross-section, or a substantially triangular cross-section, or a substantially polygonal cross-section. In the context of this document, the above-mentioned shapes and cross-sections preferably refer to the shape or cross-section of the receiving cavity without taking into account any protrusions.

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 generating device. This advantageously provides the possibility of modular assembly of the aerosol generating device.

Alternatively, at least part of the receiving cavity may be formed as a single unit with the main body. By providing at least part of the receiving cavity as part of the main body, it is possible to reduce the number of parts required to create the aerosol generating device.

The sound generating element may be located in the distant end portion of the receiving cavity, in particular on the distant end surface of the receiving cavity. The distant end surface of the receiving cavity may be formed by an element in the form of a wall separating the receiving cavity from other parts of the device, in particular from the part of the device containing a vibration sensor and/or electronic components (electrical circuit, controller, power supply). Preferably, the vibration sensor is located on the side of such an element in the form of a wall opposite to the side of the element in the form of a wall forming the distant end surface of the receiving cavity.

In addition to the vibration sensor, the puff detector may further comprise an electrical circuit for converting the output signal of the vibration sensor into a signal indicating a sound. The electrical circuit may comprise at least one of the following: a current-controlled voltage amplifier for converting current into voltage, a signal conversion amplifier, an unbalanced-to-differential signal converter, an analog-to-digital converter, and a microcontroller.

The puff detector or the electrical circuit may further comprise one or more electronic filters for filtering the output signal of the vibration sensor. Advantageously, the filtering may allow for the reduction of various types of noise, in particular parasitic noise detected by the vibration sensor.

In general, aerosol generation, in particular the release of a substance from an aerosol-forming substrate into an air stream passing through the device, can be implemented in a variety of ways, as described in more detail above.

For example, the device may comprise a nebulizer for dispersing particles or droplets of an aerosol-forming substrate into an air stream so as to form an inhalable aerosol. The nebulizer may be an ultrasonic nebulizer.

Alternatively, the aerosol generating device may comprise an electrical heater for heating an aerosol forming substrate capable of releasing volatile compounds that form an inhalable aerosol when heated and released into an air stream.

The electric heater of the aerosol generating device may be an induction heater. The induction heater may comprise an induction source comprising an inductor configured to generate an alternating, in particular high-frequency, electromagnetic field inside the device, in particular inside the receiving cavity of the device, as described above. The alternating, in particular high-frequency, electromagnetic field may be in the range from 500 kHz (kilohertz) to 30 MHz (megahertz), in particular from 5 MHz to 15 MHz, preferably from 5 MHz to 10 MHz. The alternating electromagnetic field is used for inductive heating of the current collector, which is in thermal contact with the heated aerosol-forming substrate, or in thermal proximity to it. The inductor may be arranged so as to surround the current collector and at least part of the aerosol-forming substrate during use of the device. The inductor may be an induction coil, for example a helical coil, arranged in the side wall of the receiving cavity. For example, the inductor may be positioned to surround at least a portion of the receiving cavity.

Alternatively, the heater may be a resistive heater comprising a resistive heating element. The resistive heating element is configured to heat up when an electric current passes through it, due to the inherent ohmic resistance or resistive load of the resistive heating element. For example, the resistive heating element may comprise a resistive heating wire, a resistive heating track, a resistive heating grid or a resistive heating mesh. During use of the device, the resistive heating element is in thermal contact with the heated substrate forming the aerosol, or in thermal proximity to it.

The aerosol generating device may further comprise a controller operatively connected to the puff detector for determining a puff of the user based on signals provided by the vibration sensor, in particular based on a signal provided by the puff detector that indicates an air flow passing along the air path in the device.

The controller may be further configured to control the entire operation of the aerosol-generating device, in particular the heating process. Based on the signal indicating the air flow, the controller may in particular be configured to control the release of the substance from the aerosol-forming substrate into the air flow. For example, if the aerosol-generating device comprises an electric heater for heating the aerosol-forming substrate, the controller may be operatively connected to the heater and configured to control the heating process in order to maintain the heating temperature at a certain level when the user takes a puff.

The controller and at least parts of the puff detector can be formed as a single unit with the general electrical circuit of the aerosol generating device.

The aerosol generating device may comprise a power supply, preferably a battery such as a lithium iron phosphate battery. Alternatively, the power supply may be another type of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that allows storing sufficient energy for one or more user consumption sessions. For example, the power supply may have a capacity sufficient to enable continuous aerosol generation for a period of approximately six minutes or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to enable a given number of puffs or individual activations of the heating device.

The present invention further 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 intended for heating by the device, wherein at least a part of the article is removably positioned or is removably positioned in the device, in particular in a receiving cavity of the device.

The aerosol-generating article may be a consumable, in particular intended for single use. 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 conventional cigarettes.

The article may comprise one or more of the following elements: a filter element, a cooling element, a first support element, an element in the form of a substrate, and an optional second support element. Preferably, the aerosol-generating article comprises at least a first support element, a second support element, and an element in the form of a substrate located between the first support element and the second support element.

All the above-mentioned elements can be arranged sequentially along the length axis of the article in the above-described order, wherein the first supporting element is preferably arranged at the far end of the article, and the filter element is preferably arranged at the near end of the article. Each of the above-described elements can be substantially cylindrical. In particular, all the elements can have the same external cross-sectional shape. In addition, the elements can be surrounded by an external wrapper to hold the elements together and maintain the desired cross-sectional shape of the rod-shaped article. Preferably, the wrapper is made of paper.

In the case of an inductively heated aerosol generating system, the article may further comprise a current collector. The current collector is located in thermal proximity to the aerosol forming substrate or in thermal contact with it, as a result of which, in use, the induction heating device is capable of inductively heating the current collector when the article is placed in the cavity of the device. For example, the current collector may be a strip current collector, or a plate current collector, or a tube current collector, or a sleeve current collector. The current collector may be part of an element in the form of a substrate. In the context of this document, the term "current collector" means an element that can convert electromagnetic energy into heat when exposed to an alternating magnetic field. This may be a result of hysteresis losses and/or eddy currents induced in the current collector, depending on the electrical and magnetic properties of the current collector material. Hysteresis losses occur in ferromagnetic or ferrimagnetic current collectors due to the reversal of magnetic domains within the material under the influence of an alternating electromagnetic field. Eddy currents can be induced if the current collector is electrically conductive. In the case of an electrically conductive ferromagnetic or ferrimagnetic current collector, heat can be generated by both eddy currents and hysteresis losses.

At least one of the first support element and the second support element may comprise a central air passage. Preferably, at least one of the first support element and the second support element may comprise a hollow tube made of cellulose acetate. Alternatively, the first support element may be used to close and protect the distal front end of the element in the form of a substrate.

The aerosol cooling element is an element having a large surface area and low draw resistance, for example, from 15 mm H2O to 20 mm H2O. In use, the aerosol formed by volatile compounds released from the element as a substrate is drawn through the aerosol cooling element, allowing the aerosol to be formed and cooled before moving to the proximal end of the aerosol generating article.

The filter element preferably serves as a mouthpiece or as part of a mouthpiece together with an aerosol cooling element. In the context of this document, the term "mouthpiece" refers to the part of the article through which the aerosol exits the aerosol-generating article.

Similarly, the aerosol generating article may be a capsule containing an aerosol-forming powder (as an aerosol-forming substrate) intended to be sprayed into an air stream to create an aerosol.

Additional features and advantages of the aerosol generating system and aerosol generating article according to the present invention have already been described above in relation to the aerosol generating device and are equally applicable.

In the context of this document, the term "aerosol-forming substrate" refers to a substrate that can release volatile compounds that can form an aerosol.

In particular, the aerosol-forming substrate may be a substrate capable of releasing volatile compounds that can form an aerosol upon heating. Such an aerosol-forming substrate is designed to be heated, rather than burned, to release the volatile compounds that form an aerosol. The aerosol-forming substrate may be a solid aerosol-forming substrate, or a liquid aerosol-forming substrate, or a gel-like aerosol-forming substrate, or any combination thereof. In other words, the aerosol-forming substrate may contain, for example, both solid and liquid components. The aerosol-forming substrate may contain 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 contain a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol-forming substance. Examples of suitable aerosol-forming substances are glycerol and propylene glycol. The aerosol-forming substrate may also comprise other additives and ingredients, such as nicotine or flavoring agents. The aerosol-forming substrate may also be a paste-like material, a pouch of porous material containing an aerosol-forming substrate, or, for example, loose tobacco mixed with a gelling agent or adhesive, which may comprise a conventional aerosol-forming substance, such as glycerol, and which is pressed or molded into a rod.

Similarly, the aerosol-forming substrate may be an aerosol-forming powder. The aerosol-forming powder may comprise nicotine. The term "nicotine" refers to 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 monopyruvate, nicotine hydrochloride, and combinations thereof.

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

The nicotine powder particles may be surface modified, for example, nicotine salt particles may be coated. A preferred coating material is L-leucine. Particularly suitable nicotine powder particles comprise nicotine bitartrate coated with L-leucine, nicotine glutamate coated with L-leucine, and aspartate coated with L-leucine.

The capsule preferably contains from about 5 to about 20 milligrams of nicotine powder, in particular about 10 milligrams of nicotine powder. Preferably, the capsule contains a sufficient amount of nicotine powder to deliver it to the user in about 10 to about 30 puffs.

The nicotine powder described herein does not contain carriers. The absence of carriers may allow the nicotine powder to be inhaled and delivered to the user's lungs at inhalation or air flow rates that are similar to inhalation or air flow rates in a typical smoking mode. In addition, since the nicotine powder does not contain carriers, the air flow path in the inhaler may have a simple geometry or a simple configuration.

However, the aerosol-forming powder may further comprise carrier particles which serve to enhance the fluidization of the active particles and to improve the uniformity of the dose by acting as a diluent or bulking agent in the formulation.

As an alternative or in addition to the nicotine powder, the aerosol-forming powder may also contain another active agent or ingredient, such as an active pharmaceutical material. This active agent or ingredient may be mixed in the same capsule. The second active agent or ingredient may have a similar average particle diameter range to the nicotine powder described above.

The following is a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1: An electrically powered aerosol generating device for generating an aerosol by releasing an aerosol forming substrate substance into an air stream, the device comprising:

an air path passing through the device and configured to maintain air flow in the device;

a sound generating element located in fluid communication with an air path and configured to generate a sound caused by an air flow passing through the sound generating element during use of the device when the user takes a puff; and

a puff detector comprising a vibration sensor, wherein the vibration sensor is fluidly separated from the air path and is configured to detect sound propagating from the sound generating element to the vibration sensor, thereby allowing detection of air flow passing through the device indicative of a user puff.

Example Ex2: An aerosol generating device according to example Ex 1, wherein the sound generating element comprises a sound generating displacing structure for at least partially displacing the air flow as it passes through the sound generating displacing structure.

Example Ex3: An aerosol generating device according to example Ex2, wherein the sound generating displacing structure comprises at least one of one or more grooves or one or more ribs, one or more recesses or one or more projections.

Example Ex4: An aerosol generating device according to example Ex3, wherein the longitudinal extent of one or more grooves, or the longitudinal extent of one or more ribs, or the longitudinal extent of one or more grooves and the longitudinal extent of one or more ribs is transverse, in particular perpendicular, relative to the direction of air flow passing through the sound generating element when the device is used.

Example Ex5: An aerosol generating device according to any of examples Ex3-Ex4, wherein one or more grooves, or one or more ribs, or one or more grooves and one or more ribs have one of the following shapes: a triangular shape, a sinusoidal shape, or a rectangular shape.

Example Ex6: An aerosol generating device according to any of examples Ex3-Ex5, wherein at least one of the height of the ribs or the depth of the grooves varies, in particular increases, along the sound generating displacing structure in the direction of the air flow passing through the sound generating element when the device is used.

Example Ex7: An aerosol generating device according to any of examples Ex3-Ex6, wherein a plurality of grooves, ribs, recesses or projections are uniformly or non-uniformly distributed along the air passage.

Example Ex8: An aerosol generating device according to any of examples Ex1-Ex7, wherein the sound generating element, in particular the sound generating displacing structure, is part of a wall element forming at least part of the path for air passing through the device, or is formed as a single unit with this element.

Example Ex9: An aerosol generating device according to any of examples Ex2-Ex8, wherein the sound generating displacing structure comprises a periodic circuit.

Example Ex10: An aerosol generating device according to example Ex9, wherein the periodic circuit has a period length in the range from 0.1 millimetres to 2 millimetres, in particular from 0.2 millimetres to 1 millimetre, preferably from 0.25 millimetres to 0.5 millimetres.

Example Ex11: An aerosol generating device according to any of examples Ex8-Ex10, wherein the periodic circuit is a linear periodic circuit or a non-linear periodic circuit.

Example Ex12: An aerosol generating device according to any of examples Ex8-Ex11, wherein the periodic pattern is a one-dimensional periodic pattern, in particular a sequence of several parallel grooves or ribs.

Example Ex13: An aerosol generating device according to any one of examples Ex8-Ex11, wherein the periodic pattern comprises a first sequence of several parallel first grooves or first ribs having a first periodicity in a first direction, and a second sequence of several parallel second grooves or second ribs having a second periodicity in a second direction.

Example Ex14: An aerosol generating device according to example Ex 13, wherein the first direction and the second direction are transverse, in particular perpendicular, to each other.

Example Ex15: An aerosol generating device according to any of examples Ex8-Ex10, wherein the periodic pattern comprises at least one or more curved, in particular annular, grooves or one or more curved, in particular annular, ribs.

Example Ex16: An aerosol generating device according to any one of examples Ex8 to Ex10, wherein the periodic pattern comprises a concentric ring pattern formed by a plurality of annular grooves or a plurality of annular ribs.

Example Ex17: An aerosol generating device according to any of examples Ex8 to Ex10, wherein the periodic pattern comprises a spiral pattern formed by a spiral groove or a spiral rib.

Example Ex18: An aerosol generating device according to any one of examples Ex3 to Ex10, wherein the periodic circuit may comprise a honeycomb-shaped circuit comprising a plurality of grooves or ribs forming the outline of the honeycomb-shaped circuit.

Example Ex19: An aerosol generating device according to any of examples Ex2-Ex18, wherein the sound generating displacing structure is a rigid structure.

Example Ex20: An aerosol generating device according to any of the previous examples, wherein the sound generating element, in particular the sound generating displacing structure, is a separate part or element separate from the wall element forming at least part of the path for air passing through the device, in particular a separate part or element connected to the wall element.

Example Ex21: An aerosol generating device according to any of the previous examples, wherein the sound generating element comprises at least one air flow driven vibrating element configured to periodically interrupt the air flow passing through the vibrating element.

Example Ex22: An aerosol generating device according to example Ex21, wherein at least one vibrating element comprises a tongue, or a thin plate, or a pair of tongues, or a pair of thin plates.

Example Ex23: An aerosol generating device according to any of the previous examples, wherein the air path and the sound generating element are designed such that the sound generated when the device is used is in a frequency range above 15 kilohertz (kHz), preferably above 20 kilohertz (kHz), more preferably above kilohertz (kHz).

Example Ex24: An aerosol generating device according to any of the previous examples, wherein the vibration sensor is located in a compartment of the device that is fluidly separated from the path of air passing through the device.

Example Ex25: An aerosol generating device according to example Ex 24, wherein a compartment of the device which is fluidly separated from the air path is in fluid communication with the environment outside the device.

Example Ex26: An aerosol generating device according to example Ex 24, wherein the compartment of the device which is fluidly separated from the air path is hermetically fluidly separated from the environment surrounding the device, in particular from the ambient air outside the device.

Example Ex27: An aerosol generating device according to any of the previous examples, wherein the vibration sensor comprises a microphone, an accelerometer, a strain gauge or a piezoelectric transducer or a magnetic acoustic transducer.

Example Ex28: An aerosol generating device according to any of the previous examples, wherein the vibration sensor is located on a side of the wall element opposite to the side of the wall element forming at least part of the path for air passing through the device.

Example Ex29: An aerosol generating device according to any of the previous examples, wherein the device comprises a receiving cavity for removably receiving an aerosol-generating substrate or at least a portion of an aerosol-generating article containing the substrate.

Example Ex30: An aerosol generating device according to example Ex29, wherein the receiving cavity may comprise an insertion opening through which an aerosol-forming substrate or an aerosol-generating article can be inserted into the receiving cavity.

Example Ex31: An aerosol generating device according to any of examples Ex29-Ex30, wherein the air path extends at least partially along the inner surface of the receiving cavity and/or through a wall forming at least part of the receiving cavity.

Example Ex32: An aerosol generating device according to any of examples Ex29-Ex31, wherein the sound generating element is located in the distal end portion of the receiving cavity, in particular on the distal end surface of the receiving cavity.

Example Ex33: An aerosol generating device according to any of the previous examples, wherein the puff detector comprises one or more electronic filters for filtering the output signal of the vibration sensor.

Example Ex34: An aerosol generating device according to any of the previous examples further comprises a nebulizer for spraying particles or droplets of an aerosol-forming substrate into an air stream so as to form an inhalable aerosol.

Example Ex35: The aerosol generating device according to any of the examples Ex1-Ex33 further comprises an electric heater for heating the aerosol forming substrate.

Example Ex36: An aerosol generating device according to example Ex35, wherein the contained electric heater is an induction heater or a resistive heater.

Example Ex37: An aerosol generating device according to example Ex35, wherein the induction heater comprises an inductor, in particular an induction coil, for generating an alternating magnetic field inside the device, in particular inside the receiving cavity of the device.

Example Ex38: An aerosol generating system comprising an aerosol generating device according to any of the examples and an aerosol generating article comprising an aerosol forming substrate, where at least a part of the article is removably positioned or is removably positioned in the device, in particular in a receiving cavity of the device.

Examples of the present invention will be described below with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic sectional view of a first illustrative embodiment of an aerosol generating device according to the present invention;

Fig. 2 shows details of the aerosol generating device according to Fig. 1;

Fig. 3 shows additional details of the sound generating element of the aerosol generating device according to Fig. 1;

Fig. 4 shows details of the sound generating element of the aerosol generating device according to Fig. 1; and

Fig. 5 shows a schematic sectional view of a second illustrative embodiment of an aerosol generating device according to the present invention.

Fig. 1 schematically shows a first exemplary embodiment of an aerosol generating system 1 according to the present invention. The system 1 comprises two main components: an electrical device 100 generating an aerosol 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 in the article 190. The substrate 191 is capable of releasing volatile compounds that form an inhalable aerosol when heated and released into an air stream passing through the system 1 during use.

The aerosol generating device 100 has an elongated shape and comprises a distant part 101 and a near part 102. Inside the near part 102, the device 100 comprises a receiving cavity 120 formed in the body 110 of the device for accommodating at least a part of the aerosol generating article 190. Inside the distant part 101, the device 100 comprises electronic components, in particular a power supply unit 150 and an electrical circuit 151 containing a controller 152 for powering and controlling the operation of the aerosol generating device 100.

The article 190 has a rod-shaped form resembling the form of a conventional cigarette. In the present embodiment, the article 190 comprises four elements arranged sequentially one after the other in a coaxial alignment: an element 192 in the form of a substrate, a support element 193, an element 194 cooling an aerosol, and a filter element 195. The element 192 in the form of a substrate is located at the far end of the article 190 and comprises an aerosol-forming substrate 191 intended for heating. The aerosol-forming substrate 191 may comprise, for example, a corrugated sheet of homogenized tobacco material containing glycerin as an aerosol-forming substance. The support element 193 comprises a hollow core forming a central passage for air. The cooling element 194 has a large surface area and a low resistance to draw, allowing the aerosol formed by the volatile compounds released from the element 192 in the form of a substrate to cool before being transported to the proximal end of the article 190. The filter element 195 serves as a mouthpiece and can contain, for example, cellulose acetate fibers for filtering the aerosol. The four elements 192, 193, 194 and 195 have a substantially cylindrical shape and 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 can be wrapped around the above-mentioned elements so that the free ends of the wrapper overlap each other. The wrapper can further contain glue that glues together the free ends of the wrapper, overlapping each other.

In order to heat the substrate 191 inside the article 190, the aerosol generating device 100 according to the present invention comprises an induction heating device. The induction heating device comprises an induction coil 140 for generating an alternating, in particular high-frequency, magnetic field inside the receiving cavity 120. Preferably, the high-frequency magnetic field can exist in the range from 500 kHz (kilohertz) to 30 MHz (megahertz), in particular from 5 MHz (megahertz) to 15 MHz (megahertz), preferably from 5 MHz (megahertz) to 10 MHz (megahertz). In the present embodiment, the induction coil 140 is a spiral coil located inside the housing 110 of the device. The coil 140 surrounds a part of the cylindrical cavity 120 in a coaxial alignment with the length axis of the receiving cavity 120. The alternating magnetic field is used to inductively heat the current collector 141 located inside the substrate 191 forming the aerosol of the article 190, so as to experience the effect of the magnetic field generated by the induction coil 140, when the article 190 is placed in the cavity 120. In the present embodiment, the current collector 140 is a current collector in the form of a plate, located inside the element 192 in the form of a substrate along the length axis of the article 190 so as to be in direct physical contact with the substrate 191 forming the aerosol.

Accordingly, when the induction heating device is activated, a high-frequency alternating current passes through the induction coil 140, generating an alternating magnetic field inside the cavity 120. Depending on the magnetic and electrical properties of the material of the current collector, the alternating magnetic field causes at least one of eddy currents or hysteresis losses in the current collector 141. As a result, the current collector 141 is heated until it reaches a temperature sufficient to evaporate the volatile compounds from the substrate 191 forming the aerosol. The vaporized compounds are released and captured by an air flow passing through the article 190 from the substrate element 192 at the distal end of the article 190, through the support element 193 and the cooling element 194 to the filter element 195. Along this path, the vaporized substances cool and form an inhalable aerosol, which can subsequently exit the article 190 through the filter element 195 at the proximal end of the article 190.

According to the present invention, the aerosol generating device 100 comprises an air path 180 for passing an air flow through the system 1, into which the substances of the aerosol forming substrate can be released to form an inhalable aerosol. As indicated by the curved arrows 180 in Fig. 1, the aerosol generating system 1 according to the present embodiment comprises an air path that starts at an insertion opening 122 at the near end of the receiving cavity 120 used to insert the aerosol generating article 190 into the cavity 120. Thus, the insertion opening 122 also serves as an air inlet of the device 100. The air path 180 then extends along the inner surface of the receiving cavity 120 to the far end surface (towards the bottom) of the receiving cavity 120. The last 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 after it has been inserted into the cavity 120. As described in more detail above, the last part of the air path can be formed, for example, by gaps (free space) between projections (not shown) that are part of the inner surface of the receiving cavity 120 and are used to hold the article by clamping 190 in the cavity 120. At the far end surface (at the bottom) of the receiving cavity 120, the air path is redirected in the near direction, as shown by the curved arrows 181 in Fig. 1, so as to enter the element 192 in the form of a substrate of the article 190 generating an aerosol. From there, the air path passes further through the various elements 192, 193, 194 and 195 of the article 190, where it eventually leaves the system 1, as described above in relation to the article 190 generating an aerosol.

Accordingly, when the user takes a puff, that is, when a negative pressure is applied to the filter element 195 of the article 190 received in the cavity 120, air is drawn into the receiving cavity 120 at the edge of the insertion opening 122 and further along the air path to the bottom at the distal end of the receiving cavity 120. There, the air flow enters the aerosol generating article 190 through the substrate element 192 and passes further through the support element 193, the aerosol cooling element 194 and the filter element 195, through which it ultimately leaves the article 190. Consequently, when the induction heating device is turned on, vaporized material from the aerosol generating substrate is captured by the air flow passing through the substrate element 192 and is subsequently cooled during its further path through the support element 193, the aerosol cooling element 194 and the filter element 195 so as to form an aerosol.

In order to ensure proper redirection of the air flow into the aerosol generating article 190 at the bottom of the receiving cavity 120, the aerosol generating device 100 may comprise one or more end stops (not shown) that may be positioned at the distal end portion of the receiving cavity 130 so as to limit the depth of insertion of the article 190 into the cavity 120 and thus prevent the article 190 from adjoining the distal end surface 123 of the receiving cavity 120.

As described in more detail above, proper puff detection is important for ensuring accurate control of the heating process. For this purpose, the aerosol generating device 100 according to the present embodiment comprises a puff detector comprising a vibration sensor 170 for detecting a sound caused by the passage of an air flow through the air path 180, 181 of the device 100, which in turn indicates that the user is taking a puff. In the present embodiment, the vibration sensor 170 is a microphone, for example a microphone with a moving coil. As can be seen in Fig. 1, the vibration sensor 170 is located outside the receiving cavity 120 and is fluidly separated from the air path 180, 181 passing through the device 100. Due to the separate placement, the vibration sensor 170 is not affected by the conditions inside the air path, such as temperature and humidity. In particular, the vibration sensor 170 is isolated from suspended particles or droplets appearing due to the formation of an aerosol, and is thus protected from the formation of any sediments. In the present embodiment, the vibration sensor 170 is located in the compartment 125 in the distant part 101, which also contains the power supply unit 150 and the electrical circuit 151, containing the controller 152, as mentioned above. The compartment 125 is separated by fluid medium from the receiving cavity 120 in the near part 102 of the device 100.

In order to enhance the sound effects indicating the air flow passing through the device 100 and used to identify the user's puff, the aerosol generating device 100 further comprises a sound generating element 160. The sound generating element 160 is arranged in fluid communication with the air path 180, 181 described above and is configured to generate a sound caused by the air flow passing through the sound generating element 160 when the user takes a puff. In the present embodiment, the sound generating element 160 comprises a sound generating displacing structure configured to at least partially displace the air flow 181 when it passes through the sound generating displacing structure.

Fig. 2 , Fig. 3 and Fig. 4 show details of the sound-generating displacing structure 161 implemented in the device according to Fig. 1. In the present embodiment, the sound-generating displacing structure 161 comprises a one-dimensional series of ribs 162 arranged in a periodic pattern at the far end of the receiving cavity 120 (Figs. 2-4 are not shown to scale). Grooves 163 are formed between every two adjacent ribs 106. The cross-sectional shape of the ribs 162 is substantially triangular, so that the upper part of each rib 162 has a sharp edge.

Therefore, when the air flow 182 passes through the sound-generating displacing structure 161, the air flow 182 is partially displaced due to collisions with the ribs 162 of the displacing structure 161, which lead to turbulence of a part of the air flow 180, as indicated in Fig. 2. Due to this, part of the kinetic energy of the air flow, that is, the dynamic pressure, is converted into static pressure, which leads to the appearance of several alternating regions 185, 186 of high pressure and low pressure, as shown in Fig. 3. The alternating pattern of adiabatic compressions and compression reductions in the air flow 180 results in the appearance of an acoustic wave, i.e. sound, which propagates through the device 100. The acoustic wave is formed by the sound-generating displacing element 161 and propagates, among other things, through the wall element 111, which separates the receiving cavity 120 from the compartment 125 in terms of the fluid medium. The acoustic wave propagates further through the air inside the compartment 125 until it reaches the vibration sensor 170. There, the acoustic wave (sound) is detected, which thus indicates the presence of an air flow passing through the device 100, which in turn indicates that the user is taking a puff. The sound-generating displacing structure 161 is thus part of the wall element, i.e. the wall element 111, which forms at least part of the path for the air passing through the device 100.

In addition to the vibration sensor 170, the puff detector further comprises an electrical circuit operatively connected to the vibration sensor 170 and configured to convert the output signal of the vibration sensor 170 into a signal indicating the presence of an air flow in the receiving cavity 120. The electrical circuit may further comprise one or more electronic filters for filtering the output signal of the vibration sensor. Advantageously, the filtering may allow reducing different types of noise, in particular parasitic noise detected by the vibration sensor 170. The electrical circuit of the puff detector may be implemented as a single whole with the electrical circuit 151 comprising the controller 152. Based on the signal indicating the presence of an air flow passing through the device 100, the controller 152 may control the heating process in order to maintain the heating temperature of the substrate 191 in the article 190 at a certain level when the user takes a puff.

The length 164 of the periodic pattern of the displacing structure 161 generating sound, as shown in Fig. 4, is selected in such a way as to generate sound in a certain frequency range depending on the speed of the air flow 182. For example, if the speed of the air flow 182 at the displacing structure 161 generating sound is approximately 10 meters per second, and the displacing structure 161 contains ribs 162 every 0.25 millimeters, the sound has a frequency of approximately 40 kilohertz (kHz). This frequency is outside the frequency range that people can hear, and also outside the frequency range that many animals can hear, in particular pets, such as dogs or cats.

Fig. 5 shows a second embodiment of the aerosol generating device 100 according to the present invention. In this embodiment, the vibration sensor 270 is connected to the wall element 211, which fluidly separates the receiving cavity 220 from the compartment 225. In other words, the vibration sensor 270 is located on the side of the wall element 211 opposite the side of this wall element 211, which forms at least part of the path for air passing through the device 200, and which also forms or at least supports the expelling structure 261, generating sound. As a consequence, the vibration sensor 270 is located closer to, in particular directly connected to, the expelling structure 261, generating sound, that is to say to the sound source. Advantageously, this configuration improves the possibility of detecting the sound propagating through the device 100. In addition, the embodiment according to Fig. 5 is identical to the first embodiment shown in Figs. 1-3. Accordingly, identical or similar features are designated by the same reference numbers, but increased by 100.

For the purposes of the present description and the appended claims, except where otherwise indicated, all numbers expressing quantities, amounts, percentages, etc., are to be understood as modified in all instances by the term "about." Furthermore, all ranges include the disclosed minimum and maximum points and include any intermediate ranges therein that may or may not be specifically recited herein. Accordingly, in this context, the number A is to be understood as A ± 5% of A.

Claims (19)

1. An electrical device that generates an aerosol, the device comprising: a receiving cavity for removably accommodating an aerosol-forming substrate or at least a portion of an aerosol-generating article containing the aerosol-forming substrate; an air path passing through the device and configured to maintain air flow in the device; a sound generating element located in fluid communication with the air path and configured to generate a sound caused by the passage of an air flow through the sound generating element when said device is used, when the user takes a puff, wherein the sound generating element is located at the distal end of the receiving cavity; and a puff detector comprising a vibration sensor, wherein the vibration sensor is separated by a fluid medium from the air path and is configured to detect sound propagating from the sound generating element to the vibration sensor. 2. An aerosol generating device according to claim 1, characterized in that the sound generating element comprises a sound generating displacing structure for at least partially displacing the air flow as it passes through the sound generating displacing structure. 3. An aerosol generating device according to claim 2, characterized in that the sound generating displacing structure comprises at least one of the following: one or more grooves or one or more ribs, one or more recesses or one or more projections. 4. An aerosol generating device according to claim 3, characterized in that the lengthwise extension of one or more grooves, or the lengthwise extension of one or more ribs, or the lengthwise extension of one or more grooves and the lengthwise extension of one or more ribs is perpendicular to the direction of air flow passing through the sound generating element when using the device. 5. An aerosol generating device according to any one of paragraphs 3, 4, characterized in that one or more grooves, or one or more ribs, or one or more grooves and one or more ribs have one of the following shapes: a triangular shape, a sinusoidal shape, or a rectangular shape. 6. An aerosol generating device according to any one of claims 3 to 5, characterized in that at least one of the height of the ribs or the depth of the grooves varies, in particular increases, along the sound-generating displacing structure in the direction of the air flow passing through the sound-generating element when the device is used. 7. An aerosol generating device according to any one of claims 2 to 6, characterized in that the sound generating displacing structure is part of a wall element forming at least part of the path for air passing through the device. 8. An aerosol generating device according to any one of paragraphs 2-7, characterized in that the sound-generating displacing structure contains a periodic circuit. 9. An aerosol generating device according to claim 8, characterized in that the periodic circuit has a period length in the range from 0.1 millimeters to 2 millimeters, in particular from 0.2 millimeters to 1 millimeter, preferably from 0.25 millimeters to 0.5 millimeters. 10. An aerosol generating device according to any one of the preceding claims, characterized in that the sound generating element comprises at least one air-driven vibrating element configured to periodically interrupt the air flow passing through the vibrating element. 11. An aerosol generating device according to claim 10, characterized in that at least one vibrating element comprises a tongue, or a thin plate, or a pair of tongues, or a pair of thin plates. 12. An aerosol generating device according to any one of the preceding claims, characterized in that the air path and the sound generating element are designed such that the sound generated when using the device is in a frequency range above 15 kilohertz, preferably above 20 kilohertz, more preferably above 40 kilohertz. 13. An aerosol generating device according to any of the preceding claims, characterized in that the vibration sensor comprises a microphone, an accelerometer, a strain gauge, or a piezoelectric transducer or a magnetic acoustic transducer. 14. An aerosol generating device according to any one of the preceding claims, characterized in that the vibration sensor is located on the side of the wall element opposite the side of the wall element forming at least part of the path for air passing through the device. 15. An aerosol generating device according to any of the preceding paragraphs, characterized in that the sound generating element is located on the far end surface of the receiving cavity.