Aerosol generating device with axially movable induction heater

Abstract

The present invention relates to an aerosol-generating device (10) comprising a cavity (12) for receiving an aerosol-generating article including an aerosol-forming substrate. The device further comprises an induction heating device (14). The induction heating device comprises a susceptor device and an induction coil (16). The induction coil (16) is disposed so as to at least partially surround the susceptor device (14). The induction coil (16) is disposed so as to be axially movable along the susceptor device (14). The induction heating device comprises a guide element (42) configured to guide the axial movement of the induction coil (16).

Description

[Technical Field]

[0001] The present invention relates to an aerosol generating device. [Background technology]

[0002] It is known to provide aerosol-generating devices for generating inhalable vapors. Such devices may heat an aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate volatilize without burning the aerosol-forming substrate. The aerosol-forming substrate may be provided as part of an aerosol-generating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a cavity, such as a heating chamber, of the aerosol-generating device. A heating device may be disposed around the heating chamber to heat the aerosol-forming substrate when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. The heating device may be an induction heating device. The induction heating device may include a susceptor device and an induction coil. The heating device may be disposed around the cavity. The heat generated by the heating device may uniformly heat the aerosol-generating article received in the cavity. Uniform heating of the aerosol-generating article using a temperature high enough to produce a satisfactory aerosol may result in rapid depletion of the aerosol-forming substrate of the aerosol-generating article.

[0003] It would be desirable to have an aerosol-generating device that prevents premature depletion of the aerosol-forming substrate of an aerosol-generating article received within a cavity of the aerosol-generating device. It would be desirable to have an aerosol-generating device that allows for section-by-section heating of the aerosol-forming substrate of the aerosol-forming article. Summary of the Invention

[0004] According to an embodiment of the present invention, there is provided an aerosol-generating apparatus comprising a cavity for receiving an aerosol-generating article comprising an aerosol-forming substrate. The apparatus further comprises an induction heating apparatus comprising a susceptor apparatus and an induction coil. The induction coil is disposed at least partially surrounding the susceptor apparatus. The induction coil is disposed axially movable along the susceptor apparatus. The induction heating apparatus comprises a guide element configured to guide the axial movement of the induction coil.

[0005] The movable induction coil facilitates that portions of the susceptor device can be heated. Heating portions of the susceptor device results in heating of different portions of the substrate portion of the aerosol-generating article when the aerosol-generating article is received within the cavity. A heating region within the cavity associated with the position of the induction coil may be referred to as a heating zone. By configuring the induction coil to be movable, multiple heating zones may be provided. The heating zones may be disposed along the longitudinal axis of the cavity. The heating zones may be different from each other. The positions of the heating zones may be different from each other. The heating zones may be disposed adjacent to each other. Two heating zones may be provided. Three or more heating zones may be provided. The induction coil may be movable between two positions. The induction coil may be movable between three or more positions. The induction coil may be movable to a first position. The first position of the induction coil may correspond to a first heating zone. The induction coil may be movable to a second position. The second position may be different from the first position. The second position of the induction coil may correspond to a second heating zone. The first heating zone may be in a downstream region of the cavity. The second heating zone may be in an upstream region of the cavity. The guide element may be attached to the induction coil, or vice versa. The induction coil may be securely held within or adjacent to the guide element. The induction coil may be mounted on the guide element. The guide element may include a U-shaped recess for receiving the induction coil. The U-shaped recess may face toward the cavity. The guide element may partially surround the induction coil.

[0006] The term "axial" may refer to a direction parallel to or along the longitudinal axis of the aerosol-generating device. An axially movable induction coil may mean that only the induction coil, preferably together with the guide element, may be axially movable. The susceptor may be stationary.

[0007] The aerosol generating device may further include a housing. The housing may include a guide slot. The guide element may be engageable with or configured to engage with the guide slot. The induction heating device may be disposed inside the housing. The housing may include an inner housing and an outer housing. The guide slot may be provided in the inner housing. The guide slot may be configured as a female guide slot and the guide element as a male guide element, or vice versa. The guide element may be configured to engage with the guide slot. The guide element may be securely held within the guide slot. The guide element may have an H-shaped cross section. The guide element may extend through the guide slot. An outer portion of the guide element may be disposed radially outward of the guide slot. An inner portion of the guide element may be disposed radially inward of the guide slot. A bridge portion of the guide element may connect the inner portion of the guide element to the outer portion of the guide element. Radial movement of the guide element may be prevented by engagement between the guide element and the guide slot. Movement of the guide element may cause the induction coil to move.

[0008] The guide slot may be configured as a helical guide slot. A movement of the guide element may be allowed within the guide slot. A movement of the guide element may be allowed according to the shape of the guide slot. A helical guide slot may allow a helical movement of the guide element. A tangential movement of the guide element combined with an axial movement of the guide element may be allowed by the helical guide slot. Consequently, a tangential movement of the induction coil combined with an axial movement of the induction coil may be allowed by the helical guide slot.

[0009] The guide element and guide slot may be configured to allow rotational movement of the induction coil about the longitudinal axis of the aerosol generating device, thereby resulting in axial movement of the induction coil. Movement of the guide element within the guide slot may result in movement of the induction coil. This movement may result in axial movement of the induction coil. Movement of the guide element may facilitate movement of the induction coil between different positions, such as between a first position corresponding to a first heating zone and a second position corresponding to a second heating zone.

[0010] The susceptor unit may be disposed along the entire length of the cavity. The induction coil may partially surround the susceptor unit. The susceptor unit may be disposed along a portion of the cavity where a substrate portion of the aerosol-generating article is received when the aerosol-generating article is received in the cavity. The susceptor unit may surround the periphery of the cavity. The susceptor unit may completely surround the periphery of the cavity. The susceptor unit may completely surround the entire cavity. The induction coil may completely surround the susceptor unit. The induction coil may partially surround the susceptor unit. In particular, if the induction coil is configured to be movable, it may be desirable for the induction coil to partially surround the susceptor unit. Movement of the induction coil may result in the induction coil surrounding a different portion of the susceptor unit. Illustratively, the induction coil may be moved to a first position corresponding to a first heating zone, in which case the induction coil may surround a first portion of the susceptor unit. The induction coil may be moved to a second position corresponding to a second heating zone, where the induction coil may surround a second portion of the susceptor device. The first position of the induction coil may be referred to as a first heating position, and the second position of the induction coil may be referred to as a second heating position.

[0011] The aerosol generating device may further include a motor for moving the induction coil. The aerosol generating device may be configured to automatically move the induction coil between the first heating position and the second heating position. The motor may be an electric motor. The motor may be a linear motor. When the aerosol-forming substrate of the aerosol-generating article heated by the induction coil is depleted, the induction coil may be automatically moved. Illustratively, the induction coil may initially be positioned at the first heating position. After the aerosol-forming substrate contained in the first heating zone corresponding to the first heating position is depleted, the induction coil may be automatically moved. The induction coil may be automatically moved to the second heating position to heat fresh aerosol-forming substrate contained in the second heating zone corresponding to the second heating position.

[0012] Control of the motor may be facilitated by a controller as described herein. The controller may be configured to control operation of the motor depending on the operation time of the induction coil. When the induction coil is positioned at a particular position, such as a first heating position, and operates for a time exceeding a predetermined threshold, the controller may control the motor to move the induction coil toward a further position, such as a second heating position.

[0013] The susceptor device may include at least a first susceptor and a second susceptor disposed at a distance from each other along a longitudinal axis of the aerosol-generating device, and the induction coil may be configured to be movable to surround the first susceptor corresponding to the first heating position and to surround the second susceptor corresponding to the second heating position.

[0014] The first susceptor may be disposed surrounding the first heating zone. The second susceptor may be disposed surrounding the second heating zone. The first susceptor may be disposed at a distance from the second susceptor. The first susceptor may completely surround the periphery of the cavity. The second susceptor may completely surround the periphery of the cavity. The longitudinal axis of the aerosol generating device may be the same as the longitudinal axis of the cavity.

[0015] The electrical insulating element may be disposed between the first susceptor and the second susceptor. The electrical insulating element may electrically insulate the first susceptor from the second susceptor. The electrical insulating element may be ring-shaped. The electrical insulating element may have a diameter corresponding to the diameter of the first susceptor and the diameter of the second susceptor. The electrical insulating element may be tubular.

[0016] The susceptor device may comprise at least two elongated susceptor devices parallel to the longitudinal axis of the aerosol-generating device. The susceptors may be blade-shaped. The susceptors may be disposed within a cavity of the tubular device such that the aerosol-generating article can be held between the susceptors.

[0017] Gaps may be provided between the susceptors, which may allow air to be drawn radially into the aerosol-generating article.

[0018] The susceptor may be disposed around the sidewall of a cavity within the tubular device.

[0019] The present invention further relates to an aerosol-generating apparatus having a cavity for receiving an aerosol-generating article including an aerosol-forming substrate. The apparatus further includes an induction heating apparatus. The induction heating apparatus includes a susceptor apparatus and at least a first induction coil and a second induction coil. The susceptor apparatus is disposed to at least partially surround the cavity. The first induction coil is disposed to surround a first region of the susceptor apparatus. The second induction coil is disposed to surround a second region of the susceptor apparatus.

[0020] The aerosol generating device may include a power source. The power source may be a direct current (DC) power source. The power source may be electrically connected to the first induction coil. In one embodiment, the power source is a DC power source having a DC supply voltage in the range of about 2.5 volts to about 4.5 volts and a DC supply current in the range of about 1 ampere to about 10 amperes (corresponding to a DC power supply in the range of about 2.5 watts to about 45 watts). The aerosol generating device may advantageously include a direct current to alternating current (DC / AC) inverter for converting the DC current provided by the DC power source into alternating current. The DC / AC converter may include a class D or class E power amplifier. The power source may be configured to provide the alternating current. The power source may be configured to power a motor for moving the induction coil.

[0021] The power source may be a battery, such as a rechargeable lithium-ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. The power source may have a capacity that allows for the storage of sufficient energy for one or more uses of the aerosol generating device. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, corresponding to the typical time it takes to smoke one conventional cigarette, or a multiple of six minutes. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffs or for discontinuous activation.

[0022] The power source may be configured to operate at a high frequency. As used herein, the term "high frequency oscillating current" refers to an oscillating current having a frequency between 500 kilohertz and 30 megahertz. The high frequency oscillating current may have a frequency between about 1 megahertz and about 30 megahertz, preferably between about 1 megahertz and about 10 megahertz, and more preferably between about 5 megahertz and about 8 megahertz.

[0023] The induction heating device may be configured to generate heat by induction. The induction heating device comprises an induction coil and a susceptor device. A single induction coil may be provided. A single susceptor device may be provided. Preferably, more than a single induction coil is provided. A first induction coil and a second induction coil may be provided. Preferably, more than a single susceptor device is provided. Preferably, a first susceptor device and a second susceptor device are provided, or the susceptor device comprises a first susceptor and a second susceptor. The induction coil may surround the susceptor device. The first induction coil may surround the first susceptor device or the first susceptor. The second induction coil may surround the second susceptor device or the second susceptor. Alternatively, at least two induction coils may be provided surrounding a single susceptor device. If two or more susceptor devices are provided, an electrical insulating element as described herein is preferably provided between the susceptor devices.

[0024] The susceptor device may include a susceptor. The susceptor device may include a plurality of susceptors. The susceptor device may include a blade-shaped susceptor. Alternatively, the susceptor device may include a tubular susceptor. The blade-shaped susceptor may be disposed surrounding a cavity. The blade-shaped susceptor may be disposed inside a cavity. The blade-shaped susceptor may be disposed to hold the aerosol-generating article when the aerosol-generating article is inserted into the cavity. The blade-shaped susceptor may have a flared downstream end to facilitate insertion of the aerosol-generating article into the blade-shaped susceptor. A similar arrangement of the susceptor may be utilized when the susceptor is provided having a tubular shape. The tubular susceptor may be disposed surrounding a cavity. The tubular susceptor may be disposed within the cavity.

[0025] Air may flow into the cavity through air openings in the base of the cavity. The air may then enter the aerosol-generating article at the upstream end face of the aerosol-generating article. Alternatively or additionally, air may flow between the sidewall of the cavity, preferably formed by a thermal insulating element, and a blade-shaped susceptor. The air may then enter the aerosol-generating article through the gaps between the blade-shaped susceptors. Uniform penetration of the aerosol-generating article by the air may be achieved in this way, thereby optimizing aerosol generation. If the susceptor is tubular, the tubular susceptor may have an inner diameter that corresponds to or is slightly smaller than the outer diameter of the aerosol-generating article. The aerosol-generating article may be held by the tubular susceptor. In this case, air may enter the aerosol-generating article primarily at the upstream end face of the aerosol-generating article, or only at the upstream end face of the aerosol-generating article. Alternatively, the tubular susceptor may have an inner diameter that is larger than the outer diameter of the aerosol-generating article. In this case, the air may enter the aerosol-generating article at the upstream end face of the aerosol-generating article, and in addition, the air may enter the aerosol-generating article radially from the outer periphery of the aerosol-generating article.

[0026] The aerosol generating device may include a magnetic flux concentrator. The magnetic flux concentrator may be made of a material with high magnetic permeability. The magnetic flux concentrator may be disposed surrounding the induction heating device. The magnetic flux concentrator may concentrate magnetic field lines inside the magnetic flux concentrator, thereby increasing the heating effect of the susceptor device by the induction coil. When multiple susceptor elements are provided, the magnetic flux concentrator may additionally or alternatively be disposed between the susceptor elements. The magnetic flux concentrator may be configured to concentrate magnetic field lines toward the susceptor elements surrounded by the induction coil. Exemplarily, when the induction coil is positioned at a first heating position surrounding a first susceptor element, the magnetic flux concentrator may be configured to concentrate magnetic field lines at the first susceptor. When the induction coil subsequently moves to a second heating position surrounding a second susceptor, the magnetic flux concentrator may be configured to concentrate magnetic field lines at the second susceptor. The magnetic flux concentrator is preferably stationary. It may be attached to a housing, preferably to the housing of the aerosol generating device. Alternatively, it may be movable. It may be attached to one or both of the induction coil and the guide element. It may be configured to move together with the induction coil.

[0027] The aerosol generating device may include a controller. The controller may be electrically connected to the induction coil. The controller may be electrically connected to the first induction coil and to the second induction coil. The controller may be configured to control the current supplied to the induction coil and therefore the magnetic field strength generated by the induction coil. The controller may be connected to a motor configured to move the induction coil. The controller may be configured to control the operation of the motor. The controller may be configured to control the supply of electrical energy from a power source to the motor.

[0028] The power supply and controller may be connected to the induction coils, preferably the first and second induction coils, and configured to provide alternating current to each of the induction coils independently of one another, such that, in use, each induction coil generates an alternating magnetic field. This means that the power supply and controller may be able to provide alternating current to the first induction coil alone, the second induction coil alone, or both induction coils simultaneously. Different heating profiles may be achieved in this manner. The heating profile may refer to the temperature of each induction coil. To heat to a high temperature, alternating current may be supplied to both induction coils simultaneously. To heat to a lower temperature or to heat only a portion of the aerosol-forming substrate of the aerosol-generating article, alternating current may be supplied only to the first induction coil. Thereafter, alternating current may be supplied only to the second induction coil.

[0029] A controller may be connected to the induction coil and the power source. The controller may be configured to control the supply of power from the power source to the induction coil. The controller may include a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit chip (ASIC) or other electronic circuit capable of providing control. The controller may include additional electronic components. The controller may be configured to regulate the current supply to the induction coil. Current may be supplied to one or both of the induction coils continuously after activation of the aerosol generating device, or may be supplied intermittently (such as with each puff).

[0030] The power supply and controller may be configured to independently vary the amplitude of the alternating current supplied to each of the first and second induction coils. In this configuration, the strength of the magnetic field generated by the first and second induction coils may be independently varied by varying the amplitude of the current supplied to each coil. This may advantageously facilitate a variable heating effect. For example, the amplitude of the current provided to one or both of the coils may be increased during startup to reduce the start-up time of the aerosol generator.

[0031] The first induction coil of the aerosol generating device may form part of a first circuit. The first circuit may be a resonant circuit. The first circuit may have a first resonant frequency. The first circuit may include a first capacitor. The second induction coil may form part of a second circuit. The second circuit may be a resonant circuit. The second circuit may have a second resonant frequency. The first resonant frequency may be different from the second resonant frequency. The first resonant frequency may be the same as the second resonant frequency. The second circuit may include a second capacitor. The resonant frequency of the resonant circuit depends on the inductance of each induction coil and the capacitance of each capacitor.

[0032] The cavity of the aerosol generating device may have an open end into which the aerosol-generating article is inserted. The cavity may have a closed end opposite the open end. The closed end may be the base of the cavity. The closed end may be closed except for the provision of an air opening disposed in the base. The base of the cavity may be flat. The base of the cavity may be circular. The base of the cavity may be disposed upstream of the cavity. The open end may be disposed downstream of the cavity. The longitudinal axis may extend between the open end and the closed end. The longitudinal axis of the cavity may be parallel to the longitudinal axis of the aerosol generating device.

[0033] The cavity may be configured as a heating chamber. The cavity may have a cylindrical shape. The cavity may have a hollow cylindrical shape. The cavity may have a circular cross section. The cavity may have an oval or rectangular cross section. The cavity may have a diameter corresponding to the diameter of the aerosol-generating article.

[0034] As used herein, the term "proximal" refers to the user end of the aerosol generating device or the mouth end of the aerosol generating device, and the term "distal" refers to the end opposite the proximal end. When referring to a cavity, the term "proximal" refers to the area closest to the open end of the cavity, and the term "distal" refers to the area closest to the closed end.

[0035] As used herein, the term "length" refers to the major dimension along the longitudinal axis of an aerosol-generating device, an aerosol-generating article, or a component of an aerosol-generating device or an aerosol-generating article.

[0036] As used herein, the term "width" refers to the major transverse dimension of an aerosol-generating device, an aerosol-generating article, or a component of an aerosol-generating device or article at a particular location along its length. The term "thickness" refers to the transverse dimension perpendicular to the width.

[0037] As used herein, the term "aerosol-forming substrate" relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate is part of an aerosol-generating article.

[0038] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of emitting a volatile compound capable of forming an aerosol. For example, the aerosol-generating article may be an article that generates an aerosol that can be directly inhaled by a user sucking or puffing on a mouthpiece at the proximal or user end of the system. The aerosol-generating article may be disposable. An article comprising an aerosol-forming substrate containing tobacco is called a tobacco stick. The aerosol-generating article may be insertable into a cavity of an aerosol-generating device.

[0039] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-generating article to generate an aerosol.

[0040] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating article, as further described and illustrated herein, with an aerosol-generating device, as further described and illustrated herein, in which the aerosol-generating article and the aerosol-generating device cooperate to generate a respirable aerosol.

[0041] As used herein, "susceptor device" means an electrically conductive element that heats when subjected to a changing magnetic field. This may be the result of eddy currents induced within the susceptor device, hysteresis losses, or both eddy currents and hysteresis losses. During use, the susceptor device is positioned in thermal contact or close thermal proximity with an aerosol-forming substrate of an aerosol-generating article received within the cavity of the aerosol-generating device. In this manner, the aerosol-forming substrate is heated by the susceptor device, thereby forming an aerosol.

[0042] The susceptor device may preferably have a cylindrical shape structured by individual blade-shaped susceptors. The susceptor device may have a shape corresponding to the shape of the corresponding induction coil. The susceptor device may have a diameter smaller than the diameter of the corresponding induction coil so that the susceptor device can be disposed inside the induction coil. As an alternative to blade-shaped susceptors, the susceptor may be tubular. The susceptor may have a cylindrical shape. The susceptor may have a hollow cylindrical shape.

[0043] The term "heating zone" refers to a portion of the length of the cavity that is at least partially surrounded by an induction coil such that a susceptor device positioned within or around the heating zone can be inductively heated by the induction coil. The heating zone may comprise a first heating zone and a second heating zone. The heating zone may be divided into a first heating zone and a second heating zone. The first heating zone may be surrounded by a first induction coil. The second heating zone may be surrounded by a second induction coil. Three or more heating zones may be provided. A plurality of heating zones may be provided. An induction coil may be provided for each heating zone. One or more induction coils may be movably disposed to surround the heating zone and may be configured for segmented heating of the heating zone. In a preferred embodiment, a single induction coil is provided that is movable between different heating zones to surround each heating zone.

[0044] As used herein, the term "coil" is interchangeable throughout with the terms "inductive coil" or "induction coil" or "inductor" or "inductor coil." A coil may be a driven (primary) coil connected to a power source.

[0045] The heating effect may be varied by independently controlling the first induction coil and the second induction coil. By providing the first induction coil and the second induction coil with different configurations, the heating effect may be varied because the magnetic field generated by each coil under the same applied current is different. For example, by forming the first induction coil and the second induction coil from different types of wire, the heating effect may be varied because the magnetic field generated by each coil under the same applied current is different. By independently controlling the first induction coil and the second induction coil and by providing different configurations for the first induction coil and the second induction coil, the heating effect may be varied because the magnetic field generated by each coil under the same applied current is different.

[0046] The induction coils may each be disposed at least partially around a heating zone, the induction coils may extend only partially around the periphery of the cavity in the region of the heating zone, or the induction coils may extend completely around the periphery of the cavity in the region of the heating zone.

[0047] The induction coil may be a planar coil disposed around a portion of the perimeter of the cavity or around the entire perimeter of the cavity. As used herein, "planar coil" means a spirally wound coil with the axis of winding perpendicular to the surface on which the coil is placed. A planar coil may lie within a flat Euclidean plane. A planar coil may also lie on a curved surface. For example, a planar coil may be wound within a flat Euclidean plane and then bent to lie on a curved surface.

[0048] Advantageously, the induction coil is helical. The induction coil may be helical and may be wound around a central space in which the cavity is located. The induction coil may be arranged around the entire periphery of the cavity.

[0049] The induction coil may be helical and concentric. The first induction coil and the second induction coil may have different diameters. The first induction coil and the second induction coil may be helical and concentric and may have different diameters. In such embodiments, the smaller of the two coils may be at least partially positioned within the larger of the first induction coil and the second induction coil.

[0050] The windings of the first induction coil may be electrically isolated from the windings of the second induction coil.

[0051] The aerosol-generating apparatus may further include one or more additional induction coils. For example, the aerosol-generating apparatus may further include a third induction coil and a fourth induction coil, each preferably associated with an additional susceptor associated with a different heating zone. When multiple susceptors are provided, a respective plurality of electrical insulating elements may be provided between the susceptors.

[0052] Advantageously, the first induction coil and the second induction coil have different inductance values. The first induction coil may have a first inductance, and the second induction coil may have a second inductance that is smaller than the first inductance. This means that the magnetic fields generated by the first induction coil and the second induction coil will have different strengths for a given current. This may facilitate different heating effects by the first induction coil and the second induction coil while applying current of the same amplitude to both coils. This may reduce the control requirements of the aerosol generating device. When the first induction coil and the second induction coil are activated independently, the induction coil with the larger inductance may be activated at a different time than the induction coil with the smaller inductance. For example, the induction coil with the larger inductance may be activated during operation, such as during a puff, and the induction coil with the smaller inductance may be activated between operations, such as between puffs. Advantageously, this may facilitate maintaining a high temperature in the cavity between uses without requiring the same power as normal use. This "preheating" may reduce the time it takes for the cavity to return to a desired operating temperature once operation of the aerosol generating device is resumed. Alternatively, the first induction coil and the second induction coil may have the same inductance value.

[0053] The first induction coil and the second induction coil may be formed from the same type of wire. Advantageously, the first induction coil is formed from a first type of wire, and the second induction coil is formed from a second type of wire that is different from the first type of wire. For example, the wire compositions or cross sections may be different. In this manner, the inductances of the first induction coil and the second induction coil may be different even when the overall coil geometry is the same. This may allow the same or similar coil geometries to be used for the first induction coil and the second induction coil. This may facilitate a more compact arrangement.

[0054] The first type of wire may include a first wire material, and the second type of wire may include a second wire material that is different from the first wire material. The electrical properties of the first wire material may differ from the electrical properties of the second wire material. For example, the first type of wire may have a first resistivity, and the second type of wire may have a second resistivity that is different from the first resistivity.

[0055] Suitable materials for the induction coil include copper, aluminum, silver, and steel. Preferably, the induction coil is formed from copper or aluminum.

[0056] When the first induction coil is formed from a first type of wire and the second induction coil is formed from a second type of wire that is different from the first type of wire, the first type of wire may have a different cross-section than the second type of wire. The first type of wire may have a first cross-section, and the second type of wire may have a second cross-section that is different from the first cross-section. For example, the first type of wire may have a first cross-sectional shape, and the second type of wire may have a second cross-sectional shape that is different from the first cross-sectional shape. The first type of wire may have a first thickness, and the second type of wire may have a second thickness that is different from the first thickness. The cross-sectional shapes and thicknesses of the first type of wire and the second type of wire may be different.

[0057] The susceptor device may be formed from any material that can be inductively heated to a temperature sufficient to aerosolize the aerosol-forming substrate. Suitable materials for the susceptor device include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Preferred susceptor devices include metal or carbon. Advantageously, the susceptor device may include or consist of ferromagnetic materials, such as ferritic iron, ferromagnetic steel, or stainless steel, ferromagnetic particles, and ferrite. Suitable susceptor devices may be or include aluminum. The susceptor device may include more than 5 percent ferromagnetic or paramagnetic material, preferably more than 20 percent ferromagnetic or paramagnetic material, and more preferably more than 50 percent or more than 90 percent ferromagnetic or paramagnetic material. Preferred susceptor devices may be heated to temperatures exceeding 250 degrees Celsius.

[0058] The susceptor device may be formed from a single layer of material, which may be a steel layer.

[0059] The susceptor device may include a non-metallic core having a metallic layer disposed thereon. For example, the susceptor device may include a ceramic core or a metallic track formed on the outer surface of the substrate.

[0060] The susceptor device may be formed from a layer of austenitic steel. One or more layers of stainless steel may be disposed on the layer of austenitic steel. For example, the susceptor device may be formed from a layer of austenitic steel with a layer of stainless steel on each of its upper and lower surfaces. The susceptor device may comprise a single susceptor material. The susceptor device may include a first susceptor material and a second susceptor material. The first susceptor material may be disposed in intimate physical contact with the second susceptor material. The first susceptor material and the second susceptor material may be in intimate contact to form a single, indestructible susceptor. In one particular embodiment, the first susceptor material is stainless steel and the second susceptor material is nickel. The susceptor device may have a two-layer structure. The susceptor device may be formed from a stainless steel layer and a nickel layer.

[0061] The intimate contact between the first susceptor material and the second susceptor material may be achieved by any suitable means. For example, the second susceptor material may be plated, deposited, coated, clad, or welded onto the first susceptor material. Preferred methods include electroplating, galvanizing, and cladding.

[0062] The second susceptor material may have a Curie temperature below 500 degrees Celsius. The first susceptor material may be primarily used to heat the susceptor when it is placed in an alternating electromagnetic field. Any suitable material may be used. For example, the first susceptor material may be aluminum or an iron-based material such as stainless steel. Preferably, the second susceptor material is primarily used to indicate when the susceptor reaches a specific temperature (the Curie temperature of the second susceptor material). The Curie temperature of the second susceptor material can be used to regulate the temperature of the entire susceptor during operation. Therefore, the Curie temperature of the second susceptor material should be below the ignition point of the aerosol-forming substrate. Suitable materials for the second susceptor material may include nickel and certain nickel alloys. The Curie temperature of the second susceptor material may be selected to be preferably less than 400°C, preferably less than 380°C, or even less than 360°C. The second susceptor material is preferably a magnetic material selected to have a Curie temperature substantially equal to the desired maximum heating temperature. That is, the Curie temperature of the second susceptor material is preferably approximately equal to the temperature to which the susceptor must be heated to generate an aerosol from the aerosol-forming substrate. The Curie temperature of the second susceptor material may be, for example, in the range of 200°C to 400°C, or in the range of 250°C to 360°C. In some embodiments, it may be preferable for the first susceptor material and the second susceptor material to be co-laminated. The co-laminarization may be formed by any suitable means. For example, strips of the first susceptor material may be welded or diffusion bonded to strips of the second susceptor material. Alternatively, a layer of the second susceptor material may be deposited or plated onto the strip of the first susceptor material.

[0063] The aerosol generating device is preferably portable. The aerosol generating device may have a size comparable to a conventional cigar or cigarette. The system may be an electrically operated smoking system. The system may be a handheld aerosol generating system. The aerosol generating device may have a total length of approximately 30 millimeters to approximately 150 millimeters. The aerosol generating device may have an outer diameter of approximately 5 millimeters to approximately 30 millimeters.

[0064] The housing may be elongated. The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composites containing one or more of these materials, or thermoplastics suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. Preferably, the material is light and not brittle.

[0065] The housing may include a mouthpiece. The mouthpiece may include at least one air inlet and at least one air outlet. The mouthpiece may include two or more air inlets. One or more of the air inlets may reduce the temperature of the aerosol before it is delivered to the user and may reduce the concentration of the aerosol before it is delivered to the user.

[0066] Alternatively, the mouthpiece may be provided as part of the aerosol-generating article.

[0067] As used herein, the term "mouthpiece" refers to the portion of an aerosol generating device that is placed into the user's mouth for direct inhalation of aerosol generated by the aerosol generating device from an aerosol-generating article received within a cavity of the housing.

[0068] The air intake port may be configured as a semi-open inlet. A semi-open inlet preferably allows air to enter the aerosol generating device. Air or liquid may be prevented from exiting the aerosol generating device through the semi-open inlet. The semi-open inlet may be, for example, a semi-permeable membrane that is permeable to air in only one direction but is airtight and liquid-tight in the opposite direction. The semi-open inlet may also be, for example, a one-way valve. A semi-open inlet preferably allows air to pass through the inlet only when certain conditions are met, such as a minimum pressure on the aerosol generating device or the amount of air passing through the valve or membrane.

[0069] Operation of the heating device may be triggered by a puff detection system. Alternatively, the heating device may be triggered by pressing an on / off button and maintained for the duration of the user's puff. The puff detection system may be provided as a sensor, which may be configured as an airflow sensor to measure airflow velocity. Airflow velocity is a parameter that characterizes the amount of air per time drawn by the user through the airflow path of the aerosol generating device. The onset of a puff may be detected by the airflow sensor when the airflow exceeds a predetermined threshold. Onset may also be detected when the user activates a button.

[0070] The sensor may also be configured as a pressure sensor for measuring the pressure of air inside the aerosol-generating device that is drawn through the airflow path of the device by the user during a puff. The sensor may be configured to measure the pressure difference or pressure drop between the pressure of the ambient air outside the aerosol-generating device and the pressure of the air drawn through the device by the user. The air pressure may be detected at the air inlet, the mouthpiece of the device, or a cavity (such as a heating chamber or any other passage or chamber within the aerosol-generating device through which air flows). When a user draws on the aerosol-generating device, a negative pressure or vacuum is created inside the device, and this negative pressure may be detected by the pressure sensor. The term "negative pressure" is understood as a pressure that is relatively lower than the pressure of the ambient air. In other words, when a user draws on the device, the air drawn through the device has a pressure that is lower than the pressure of the ambient air outside the device. The start of a puff may be detected by the pressure sensor when the pressure difference exceeds a predetermined threshold.

[0071] The aerosol generating device may include a user interface for activating the aerosol generating device, such as a button to initiate heating of the aerosol generating device, or a display that indicates the status of the aerosol generating device or the aerosol-forming substrate.

[0072] An aerosol generating system is a combination of an aerosol generating device and one or more aerosol generating articles for use with the aerosol generating device, but may also include additional components, such as an electrically operated aerosol generating device or a charging unit for recharging an on-board power supply in an electric aerosol generating device.

[0073] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix. The aerosol-forming substrate may comprise a plant-derived material. The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may comprise a tobacco-containing material comprising volatile tobacco flavour compounds that are released from the aerosol-forming substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise a homogenized plant-derived material. The aerosol-forming substrate may comprise a homogenized tobacco material. The homogenized tobacco material may be formed by agglomerating particulate tobacco. In a particularly preferred embodiment, the aerosol-forming substrate may comprise an assembly of a crimped sheet of homogenized tobacco material. As used herein, the term "crimped sheet" means a sheet having a plurality of substantially parallel ridges or corrugations.

[0074] The aerosol-forming substrate may include at least one aerosol former. The aerosol former is any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol during use and is substantially resistant to thermal decomposition at the operating temperatures of the system. Suitable aerosol formers are well known in the art and include, but are not limited to, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate). Preferred aerosol formers are polyhydric alcohols or mixtures thereof (e.g., triethylene glycol, 1,3-butanediol, etc.). Preferably, the aerosol former is glycerin. When present, the homogenized tobacco material may have an aerosol former content of 5 weight percent or more on a dry weight basis, and preferably has an aerosol former content of 5 weight percent to 30 weight percent on a dry weight basis. The aerosol-forming substrate may also include other additives and ingredients, such as flavorants.

[0075] In any of the above embodiments, the aerosol-generating article and the cavity of the aerosol-generating device may be arranged such that the aerosol-generating article is partially received within the cavity of the aerosol-generating device, or the aerosol-generating device and the cavity of the aerosol-generating article may be arranged such that the aerosol-generating article is completely received within the cavity of the aerosol-generating device.

[0076] The aerosol-generating article may be substantially cylindrical in shape. The aerosol-generating article may be substantially elongated. The aerosol-generating article may have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may be provided as an aerosol-forming segment containing the aerosol-forming substrate. The aerosol-forming segment may be substantially cylindrical in shape. The aerosol-forming segment may be substantially elongated. The aerosol-forming segment may also have a length and a circumference substantially perpendicular to the length.

[0077] The aerosol-generating article may have an overall length of approximately 30 millimeters to approximately 100 millimeters. In one embodiment, the aerosol-generating article has an overall length of approximately 45 millimeters. The aerosol-generating article may have an outer diameter of approximately 5 millimeters to approximately 12 millimeters. In one embodiment, the aerosol-generating article may have an outer diameter of approximately 7.2 millimeters.

[0078] The aerosol-forming substrate may be provided as an aerosol-forming segment having a length of about 7 millimeters to about 15 millimeters. In one embodiment, the aerosol-forming segment may have a length of approximately 10 millimeters. Alternatively, the aerosol-forming segment may have a length of approximately 12 millimeters.

[0079] The aerosol-generation segment preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The outer diameter of the aerosol-forming segment may be from approximately 5 millimeters to approximately 12 millimeters. In one embodiment, the aerosol-forming segment may have an outer diameter of approximately 7.2 millimeters.

[0080] The aerosol-generating article may include a filter plug. The filter plug may be located at the downstream end of the aerosol-generating article. The filter plug may be a cellulose acetate filter plug. The filter plug may be a hollow cellulose acetate filter plug. In one embodiment, the filter plug is approximately 7 millimeters long, but may have a length of approximately 5 millimeters to approximately 10 millimeters.

[0081] As used herein, the terms "upstream" and "downstream" are used to describe the relative location of a component or portion of a component of an aerosol generating device with respect to the direction in which a user draws on the aerosol generating device during use.

[0082] The aerosol-generating article may include an outer paper wrapper. Additionally, the aerosol-generating article may include a separation between the aerosol-forming substrate and the filter plug. The separation may be approximately 18 millimeters, but may also be in the range of approximately 5 millimeters to approximately 25 meters.

[0083] Features described with respect to one embodiment may equally apply to other embodiments of the invention.

[0084] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0085] [Figure 1] FIG. 1 shows an exemplary diagram of an aerosol generating device of the present invention. [Figure 2] FIG. 2 shows an exemplary diagram of the aerosol generating device of FIG. 1 with a moved induction coil. [Figure 3] FIG. 3 shows the aerosol generating device of FIGS. 1 and 2 with guide slots in the housing of the aerosol generating device. [Figure 4] FIG. 4 shows the aerosol generating device of any of FIGS. 1 to 3 during heating operation. [Figure 5] FIG. 5 shows the aerosol generating apparatus of any of FIGS. 1-4 with details regarding the susceptor arrangement. [Figure 6] FIG. 6 shows a further embodiment of an aerosol generating device having a blade-shaped susceptor. [Figure 7] FIG. 7 shows an embodiment of an aerosol generating device with two induction coils. DETAILED DESCRIPTION OF THE INVENTION

[0086] Figure 1 shows the proximal or downstream portion of an aerosol-generating device. The aerosol-generating device comprises a cavity 10 for insertion of an aerosol-generating article 12. The aerosol-generating article 12 is illustrated in Figures 2, 4, and 6. The cavity 10 is configured as a heating chamber.

[0087] Disposed inside the cavity 10 is a susceptor device 14. The inner diameter of the susceptor device 14 may correspond to or be slightly smaller than the outer diameter of the aerosol-generating article 12. The aerosol-generating article 12 may be held by the susceptor device 14 after insertion of the aerosol-generating article 12 into the cavity 10. Alternatively, the inner diameter of the susceptor device 14 may be larger than the outer diameter of the aerosol-generating article 12. The susceptor device 14 may have a tubular shape.

[0088] The susceptor device 14 is part of an induction heating device. The induction heating device includes an induction coil 16. The induction coil 16 is disposed so as to at least partially surround the cavity 10. Alternatively, the induction coil 16 may be disposed within the cavity 10. The induction coil 16 surrounds the entire circumference of the cavity 10. The induction coil 16 is disposed so as to surround the susceptor device 14. The induction coil 16 surrounds the portion of the cavity 10 in which the substrate portion 18 of the aerosol-generating article 12 is received. A filter portion 20 of the aerosol-generating article 12 protrudes from the cavity 10 after the aerosol-generating article 12 is inserted into the cavity 10. A user draws on the filter portion 20.

[0089] The induction coil 16 surrounds only a portion of the cavity 10. This portion of the cavity 10 surrounded by the induction coil 16 is called a heating zone. As seen in FIG. 1 , the induction coil 16 surrounds a downstream portion of the cavity 10. The induction coil 16 surrounds a first susceptor 22. The first susceptor 22 is disposed to surround the downstream portion of the cavity 10. The first susceptor 22 is disposed to surround a first heating zone corresponding to the space of the cavity 10 surrounded by the first susceptor 22.

[0090] The susceptor unit 14 includes multiple susceptors, three of which are shown in FIG. 1 . In addition to the first susceptor 22, a second susceptor 30 and a third susceptor 34 are also shown. The induction coil 16 is configured to be movable between different heating positions. Each heating position of the induction coil 16 corresponds to a position surrounding a susceptor 22, 30, or 34. An electrical insulating element 36 is disposed between each individual susceptor 22, 30, or 34. The electrical insulating element 36 is ring-shaped. The electrical insulating element 36 is tubular. At the upstream end of the susceptor unit 14, an electrical insulating element 36 is provided between the last susceptor 34 and the base 28 of the cavity 10. This upstream electrical insulating element 36 prevents electrical contact between the last susceptor 34 and the base 28 of the cavity 10. 1, three susceptors 22, 30, 34 are shown. However, this number is chosen for illustrative reasons. A greater or lesser number of susceptors may be provided depending on the number of heating zones desired. The number of induction coil 16 positions preferably corresponds to the number of susceptors provided.

[0091] The aerosol generating device includes additional elements not shown in the figure, such as a controller for controlling the induction heating device. If the induction heating device includes more than one induction coil 16, the controller is configured to separately control each individual coil. The aerosol generating device includes a power source, such as a battery. The controller is configured to control the supply of electrical energy from the power source to the induction coil 16, or to each individual induction coil 16.

[0092] An air opening is provided at the base 28 of the cavity 10. The air opening has an elongated extension parallel to the longitudinal axis of the aerosol generating device. The air opening allows air to enter the cavity 10 at the upstream end 32 of the cavity 10. A thermal insulating element is provided surrounding or forming the side wall of the cavity 10. The thermal insulating element prevents air from entering the cavity 10 laterally.

[0093] An air inlet is provided to allow ambient air to enter the cavity 10. The air inlet is disposed at the downstream end of the housing 24. Alternatively, the air inlet is located on the periphery of the housing 24 of the aerosol generating device.

[0094] In Figure 1, a resilient sealing element 38 is shown at the downstream end of the cavity 10. The resilient sealing element 38 is disposed surrounding the downstream end of the cavity 10. The resilient sealing element 38 has a circular shape. The resilient sealing element 38 has a funnel shape that facilitates insertion of the aerosol-generating article 12. After insertion, the resilient sealing element 38 applies pressure to the aerosol-generating article 12 to hold the aerosol-generating article 12 in place. The resilient sealing element 38 is air-impermeable to prevent air from escaping from the cavity 10 except through the aerosol-generating article 12.

[0095] A guide element 42 is provided to facilitate movement of the induction coil 16. The guide element 42 engages with a guide slot 44 in the aerosol generating device housing 24. The guide element 42 partially surrounds the induction coil 16. The induction coil 16 is mounted on the guide element 42. The guide element 42 is movable within the guide slot 44. Movement of the guide element 42 within the guide slot 44 results in movement of the induction coil 16 from the position shown in FIG. 1 to the position shown in FIG. 2.

[0096] 2 shows a diagram of an aerosol-generating device in which an aerosol-generating article 12 is inserted into a cavity 10. A substrate portion 18 of the aerosol-generating article 12 is received within the cavity 10. A filter portion 20 of the aerosol-generating article 12 may protrude from the cavity 10 for a user to inhale the aerosol-generating article 12.

[0097] In addition to the inserted aerosol-generating article 12, FIG. 2 also shows the induction coil 16 moved to the second heating position. In the second heating position, the induction coil 16 surrounds the second susceptor 30 of the susceptor device 14. Movement from the first heating position to the second heating position is automatically facilitated by a motor. In particular, movement from the first heating position to the second heating position is facilitated when the aerosol-forming substrate of the aerosol-generating article 12 in the first heating zone corresponding to the first heating position of the induction coil 16 is depleted. After this depletion of the aerosol-forming substrate, the induction coil 16 is automatically moved to the second heating position in several ways. Instead of automatically moving the induction coil 16 by a motor, movement can also be initiated by a user, in particular by rotation of the outer portion of the guide element 42 so that the guide element 42 slides within the guide slot 44. The aerosol-generating device may also include means for indicating to a user that the aerosol-forming substrate in the first heating zone has been depleted. Illustratively, the aerosol generating device may be equipped with optical means to indicate to the user that the induction coil 16 should be moved.

[0098] 3 shows the guide slot 44 in more detail. The guide slot 44 preferably has a helical shape, so that rotational movement of the guide element 42 results in axial movement of the induction coil 16.

[0099] FIG. 4 illustrates operation of the induction coil 16 in the second heating position to heat the aerosol-forming substrate of the aerosol-forming article 12 in the second heating zone.

[0100] Figure 5 shows a detailed view of the susceptor apparatus 14. In particular, the first susceptor 22, the second susceptor 30, and the third susceptor 34 are illustrated in Figure 5. Figure 5 is an exploded view of the susceptor apparatus 14. Electrical insulating elements 36 may be disposed between the individual susceptors 22, 30, 34. Slots 46 are provided in the electrical insulating elements 36 to allow airflow through the electrical insulating elements 36 into the cavity 10.

[0101] 6 shows an embodiment of a different configuration of the susceptor device 14. In this embodiment, the susceptor device 14 is configured as a blade-shaped susceptor. The blade-shaped susceptor is elongated and extends parallel to the longitudinal axis of the cavity 10. In this embodiment, gaps 40 are provided between the blade-shaped susceptors to allow radial airflow to the aerosol-generating articles between the individual blade-shaped susceptors. The inner diameter of the blade-shaped susceptor corresponds to or is slightly smaller than the outer diameter of the aerosol-generating article 12, so that the susceptor holds the aerosol-generating article 12 in place after it is received within the cavity 10.

[0102] More than one induction coil 16 may be provided. In addition to the induction coil 16, a second induction coil 48 may be provided. Preferably, two induction coils 16, 48, or three or more induction coils are provided. The induction coils 16, 48 are part of an induction heating device. The induction coils 16, 48 are separately controllable to enable heating of separate heating zones within the cavity 10. An embodiment of two induction coils 16, 48 is illustrated in FIG. 7. Preferably, both induction coils 16, 48 are attached to a guide element 42 so that they can be moved simultaneously. The combination of providing multiple induction coils 16, 48 and configuring the induction coils 16, 48 to be movable enables a variety of potential heating regimes. Separately controlling the individual induction coils 16, 48 already enables separate heating of at least two heating zones. Additionally, movement of the induction coils 16, 48 by movement of the guide element 42 within the guide slot 44 allows the induction coils 16, 48 to be moved to different heating zones. Independent control of the individual induction coils 16, 48 as well as movement of the induction coils 16, 48 to different heating locations may be combined as desired.

Claims

1. An aerosol generating device, comprising: a cavity for receiving an aerosol-generating article comprising an aerosol-forming substrate; an induction heating device comprising: a susceptor device and an induction coil, the induction coil arranged to at least partially surround the susceptor device, the induction coil arranged to be axially movable along the susceptor device, the induction heating device comprising a guide element configured to guide the axial movement of the induction coil, the induction coil configured to be movable to at least a first heating position and a second heating position around the cavity, the susceptor device comprising at least a first susceptor and a second susceptor arranged at a distance from each other along a longitudinal axis of the aerosol generating device, the induction coil configured to be movable to surround the first susceptor corresponding to the first heating position and to surround the second susceptor corresponding to the second heating position, wherein the first and second susceptors have a hollow cylindrical shape.

2. 2. The aerosol generating device of claim 1, further comprising a housing, the housing comprising a guide slot, and the guide element being engageable with or configured to be engaged with the guide slot.

3. 3. The aerosol generating device of claim 2, wherein the guide slot is configured as a spiral guide slot.

4. 4. The aerosol generating device of claim 2 or 3, wherein the guide element and the guide slot are configured to allow rotational movement of the induction coil around the longitudinal axis of the aerosol generating device, thereby resulting in the axial movement of the induction coil.

5. 5. The aerosol generating device according to claim 1, wherein the susceptor device is disposed along the entire length of the cavity, and the induction coil partially surrounds the susceptor device.

6. An aerosol generating device according to any one of claims 1 to 5, further comprising a motor for moving the induction coil, and configured to automatically move the induction coil between the first heating position and the second heating position.

7. 7. The aerosol generating device according to claim 1, wherein an electrically insulating element is disposed between the first susceptor and the second susceptor.

8. 8. An aerosol generating device according to claim 1, wherein the induction coil is configured to be movable relative to a housing of the aerosol generating device.

9. 9. The aerosol generation device according to claim 1, wherein the susceptor device comprises at least two elongated susceptor devices arranged parallel to the longitudinal axis of the aerosol generation device.

10. 10. An aerosol generating device according to any one of claims 1 to 9, wherein a gap is provided between the susceptors.

11. 11. The aerosol generating device according to claim 1, wherein the susceptor is arranged in a tubular arrangement around a side wall of the cavity.

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