Aerosol generator comprising an inductor

Abstract

To provide an electrically operated aerosol-generating device (100) for heating an aerosol-generating article (10) including an aerosol-forming substrate (20) by heating a susceptor element (30) positioned to heat the aerosol-forming substrate.SOLUTION: The device includes a housing (110) defining a chamber (120) to receive at least a portion of the aerosol-generating article, an inductor (200) including an inductor coil (210) disposed around at least a portion of the chamber, and a power source (140) connected to the inductor coil and configured to provide a high frequency electric current to the inductor coil such that, in use, the inductor coil generates a fluctuating electromagnetic field to heat the susceptor element and thereby heat the aerosol-forming substrate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electrically operated aerosol generating device for use in an electrically operated aerosol generating system, and an electrically operated aerosol generating system comprising such an electrically operated aerosol generating device.

Background Art

[0002] Several electrically - operated aerosol - generating systems have been proposed in the art that use an electric heater to heat an aerosol - forming substrate such as a tobacco plug. One objective of such aerosol - generating systems is to reduce known harmful smoke components of the type produced by the combustion and pyrolysis of tobacco in conventional cigarettes. Generally, the aerosol - generating substrate is provided as part of an aerosol - generating article that is inserted into a chamber or recess of the aerosol - generating device. In some known systems, a resistive heating element such as a heating blade is inserted into or around the aerosol - forming substrate when the article is received by the aerosol - generating device to heat the aerosol - forming substrate to a temperature at which volatile components capable of forming an aerosol can be released. In other aerosol - generating systems, an induction heater rather than a resistive heating element is used. An induction heater generally comprises an inductor forming part of the aerosol - generating device and a conductive susceptor element arranged to be in thermal proximity to the aerosol - forming substrate. The inductor generates a varying electromagnetic field that generates eddy currents and hysteresis losses within the susceptor element, which causes heating of the susceptor element and thereby heating of the aerosol - forming substrate. Inductive heating enables the generation of an aerosol without exposing the heater to the aerosol - generating article. This can improve the ease with which the heater can be cleaned. However, with inductive heating, the inductor can also cause eddy currents and hysteresis losses in adjacent components of the aerosol - generating device outside the inductor or in other conductive articles in proximity to the aerosol - generating device. This can reduce the efficiency of the inductor, thus reducing the efficiency of the aerosol - generating device and potentially causing unwanted heating of external components or adjacent articles.

[0003] It would be desirable to provide an electrically - operated aerosol - generating device that has improved efficiency and reduces the opportunity for unwanted heating of adjacent articles. SUMMARY OF THE INVENTION

[0004] According to a first aspect of the present invention, there is provided an electrically operated aerosol generating device for heating an aerosol generating article comprising an aerosol forming substrate by heating a susceptor element positioned to heat the aerosol forming substrate. The device comprises a device housing defining a chamber for receiving at least a portion of the aerosol generating article, an inductor comprising an inductor coil disposed around at least a portion of the chamber, and a power supply connected to the inductor coil and configured to provide a high frequency current to the inductor coil such that, in use, the inductor coil generates a varying electromagnetic field to heat the susceptor element and thereby heat the aerosol forming substrate. The inductor further comprises a magnetic flux concentrator disposed around the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil towards the chamber. The magnetic flux concentrator comprises a plurality of individual magnetic flux concentrator segments.

[0005] Advantageously, by distorting the electromagnetic field towards the chamber, the magnetic flux concentrator can concentrate or focus the electromagnetic field within the chamber. This can increase the level of heat generated within the susceptor for a given level of power passing through the inductor coil compared to an inductor without a magnetic flux concentrator provided. Thus, the efficiency of the aerosol generating device can be improved.

[0006] As used herein, the phrase "concentrate the electromagnetic field" means that the magnetic flux concentrator is capable of distorting the electromagnetic field such that the density of the electromagnetic field increases within the chamber.

[0007] Furthermore, by distorting the electromagnetic field towards the chamber, the flux concentrator can also reduce the extent to which the electromagnetic field propagates beyond the inductor. In other words, the flux concentrator can serve as an electromagnetic shield. This can reduce unwanted heating of adjacent conductive components of the device (for example, when a metal outer housing is used), or adjacent conductive articles external to the device. By reducing unwanted heating and losses from the inductor coil, the efficiency of the aerosol generating device can be further improved.

[0008] As used herein, the term "aerosol-forming substrate" relates to a substrate having the ability to release a volatile compound capable of forming an aerosol. Such volatile compounds can be released by heating the aerosol-forming substrate. The aerosol-forming substrate may conveniently be part of an aerosol-generating article.

[0009] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate having the ability to release 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 by sucking or smoking on a mouthpiece at the proximal or user side end of the system. The aerosol-generating article may be disposable. An article comprising an aerosol-forming substrate comprising tobacco is referred to as a tobacco stick.

[0010] As used herein, the term "aerosol generating device" refers to a device that interacts with an aerosol-generating article to generate an aerosol.

[0011] As used herein, the term "aerosol generating system" refers to a combination of an aerosol-generating article as further described and illustrated herein and an aerosol generating device as further described and illustrated herein. In the system, the article and the device cooperate to generate an aerosol suitable for respiration.

[0012] As used herein, the term "magnetic flux concentrator" refers to a component having a high relative permeability that functions to concentrate and direct the electromagnetic field or lines of electromagnetic force generated by an inductor coil.

[0013] As used herein and in the art, the term "relative permeability" refers to the ratio of the permeability of a material or medium, such as a magnetic flux concentrator, to the permeability of free space "μ 0 ", where μ 0 is 4π×10 -7 NA -2 .

[0014] As used herein, the term "high relative permeability" refers to a relative permeability of at least 5 (e.g., at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 80, or at least 100) at 25 degrees Celsius. These exemplary values preferably refer to relative permeability values at a frequency of 6 - 8 MHz and a temperature of 25 degrees Celsius.

[0015] As used herein, the term "high - frequency oscillating current" means an oscillating current having a frequency of 500 kHz to 10 MHz.

[0016] The magnetic flux concentrator preferably includes a material or combination of materials having a relative permeability of at least 5 at 25 degrees Celsius, preferably at least 20 at 25 degrees Celsius. The magnetic flux concentrator may be formed from a plurality of different materials. In such embodiments, the magnetic flux concentrator as an overall medium may have a relative permeability of at least 5 at 25 degrees Celsius, preferably at least 20 at 25 degrees Celsius. These exemplary values preferably refer to relative permeability values at a frequency of 6 - 8 MHz and a temperature of 25 degrees Celsius.

[0017] The magnetic flux concentrator may be formed from any suitable material or combination of materials. The magnetic flux concentrator preferably includes a ferromagnetic material (e.g., a ferrite material, ferrite powder held in a binder, etc.), or any other suitable material including a ferrite material such as ferrite iron, ferromagnetic steel, or stainless steel.

[0018] The thickness of the magnetic flux concentrator will depend on, among other things, the material or combination of materials from which it is made, the shape of the inductor coil and the magnetic flux concentrator, and the desired level of electromagnetic field distortion. Careful selection of the magnetic flux concentrator material and dimensions enables the shape and density of the electromagnetic field to be adjusted according to the heating and required power of the susceptor element or elements to which the inductor is coupled during use. This "adjustment" of the magnetic flux concentrator can enable a predetermined value of electromagnetic field strength to be achieved within the chamber. For example, the magnetic flux concentrator can have a thickness of from 0.3 mm to 5 mm, preferably from 0.5 mm to 1.5 mm. In certain embodiments, the magnetic flux concentrator comprises ferrite and has a thickness of from 0.3 mm to 5 mm, preferably from 0.5 mm to 1.5 mm.

[0019] As used herein, the term "thickness" refers to the transverse dimension along the length of, or at a particular location around, a component of the aerosol generating device or aerosol generating article. With particular reference to the magnetic flux concentrator, the term "thickness" refers to half the difference between the outer diameter and the inner diameter of the magnetic flux concentrator at a particular location.

[0020] As used herein, the term "longitudinal direction" is used to describe the direction along the main axis of the aerosol generating device or aerosol generating article, and the term "transverse direction" is used to describe the direction that is perpendicular to the longitudinal direction.

[0021] The thickness of the magnetic flux concentrator may be substantially constant along its length. In other examples, the thickness of the magnetic flux concentrator may be substantially constant along its length. For example, the thickness of the magnetic flux concentrator may taper or decrease from the central portion of the magnetic flux concentrator towards one end and the other, or towards both ends. When the thickness of the magnetic flux concentrator varies along its length, either the outer diameter or the inner diameter may remain substantially constant along the length of the magnetic flux concentrator. In certain embodiments, the inner diameter of the magnetic flux concentrator is substantially constant along its length while the outer diameter decreases from one end of the magnetic flux concentrator towards the other. Such a magnetic flux concentrator may be referred to as having a "wedge-shaped" longitudinal cross-section.

[0022] The thickness of the magnetic flux concentrator may be substantially constant around its perimeter. In other examples, the thickness of the magnetic flux concentrator may vary around its perimeter.

[0023] The magnetic flux concentrator may have any suitable shape based on the shape of the inductor coil and the desired level of distortion of the electromagnetic field. The magnetic flux concentrator may extend along only a portion of the length of the inductor coil. Preferably, the magnetic flux concentrator extends substantially along the entire length of the inductor coil. The magnetic flux concentrator may extend beyond the inductor coil at one or both ends of the inductor coil.

[0024] The magnetic flux concentrator may extend only to a portion around the inductor coil. The magnetic flux concentrator is preferably tubular. In such an embodiment, the magnetic flux concentrator completely surrounds the inductor coil along at least a portion of the length of the coil. The magnetic flux concentrator may be cylindrical. In such an embodiment, the magnetic flux concentrator is tubular and its thickness is substantially constant along its length. When the magnetic flux concentrator is tubular, it may have any suitable cross-section. For example, the magnetic flux concentrator may have a square, elliptical, rectangular, triangular, pentagonal, hexagonal or similar cross-sectional shape. The magnetic flux concentrator preferably has a circular cross-sectional shape. For example, the magnetic flux concentrator may have an annular cylindrical shape. In other words, the magnetic flux concentrator may be a cylindrical annular part.

[0025] The magnetic flux concentrator comprises a plurality of individual magnetic flux concentrator segments positioned adjacent to each other. Thus, the magnetic flux concentrator is an assembly of a plurality of individual components. This makes it possible to adjust the magnetic flux concentrator, and thus the degree to which the electromagnetic field is distorted, by removing one or more magnetic flux concentrator segments from the magnetic flux concentrator or adding one or more magnetic flux concentrator segments to the magnetic flux concentrator. For example, one or more magnetic flux concentrator segments may be replaced with segments formed from a material having a low relative permeability such as plastic, to reduce the degree to which the electromagnetic field is distorted by the magnetic flux concentrator. This "adjustment" of the magnetic flux concentrator may, for example, make it possible to achieve a predetermined value of electromagnetic field strength within the chamber at the position where the susceptor element is placed during use.

[0026] As used herein, the term "adjacent to" is used to mean "next to" or "beside". This includes configurations where the segments are in direct contact, as well as configurations where two or more of the segments are separated by a gap such as a void or a gap including one or more intermediate components between adjacent segments.

[0027] Any number of individual flux concentrator segments may be provided based on a desired level of adjustment. For example, providing a large number of small segments to form a flux concentrator can allow for a refined adjustment of the electromagnetic field distortion provided by the flux concentrator compared to a flux concentrator with a smaller number of larger segments. The plurality of flux concentrator segments can comprise two individual flux concentrator segments, or more than two (e.g., three, four, five, six, seven, eight, nine, ten or more) flux concentrator segments.

[0028] The plurality of flux concentrator segments may have a uniform size and shape. In other examples, one or more of the plurality of flux concentrator segments may have a different size, shape, or size and shape compared to one or more of the other flux concentrator segments. This allows for a simple adjustment of the flux concentrator by replacing one or more of the segments with segments having different dimensions.

[0029] If the flux concentrator comprises a plurality of individual flux concentrator segments positioned adjacent to each other, the individual flux concentrator segments may be formed from the same material or combination of materials as each other. In such embodiments, the flux concentrator can be adjusted by using flux concentrator segments having different dimensions.

[0030] Preferably, the plurality of magnetic flux concentrator segments includes a first magnetic flux concentrator segment formed from a first material and a second magnetic flux concentrator segment formed from a second different material, and the first and second materials have different values of relative permeability. This allows the magnetic flux concentrator to be adjusted during assembly without necessarily changing the dimensions of the magnetic flux concentrator, thereby achieving a desired level of induction from the inductor coil and a desired level of electromagnetic flux within the chamber. Each of the magnetic flux concentrator segments can be made from different materials, or the same material, or any number of combinations thereof.

[0031] The shape of the magnetic flux concentrator segments is selected based on the desired shape of the resulting magnetic flux concentrator.

[0032] In certain embodiments, the plurality of magnetic flux concentrator segments are tubular and are positioned coaxially along the length of the magnetic flux concentrator. In such embodiments, the resulting magnetic flux concentrator is tubular and completely surrounds the inductor coil along at least a portion of the length of the coil. The tubular magnetic flux concentrator segments can be cylindrical. In other embodiments, the thickness of one or more of the tubular segments can vary along their length. When the magnetic flux concentrator segments are tubular, they can have any suitable cross-section. For example, the tubular magnetic flux concentrator segments can have a square, elliptical, rectangular, triangular, pentagonal, hexagonal or similar cross-sectional shape according to the desired shape of the resulting magnetic flux concentrator. Each tubular magnetic flux concentrator segment preferably has a circular cross-sectional shape. For example, the tubular magnetic flux concentrator segments can have an annular cylindrical shape. In other words, each of the tubular magnetic flux concentrator segments can form an annular portion of a cylinder.

[0033] In certain other embodiments, the plurality of magnetic flux concentrator segments are elongated and positioned around the magnetic flux concentrator. As used herein, the term "elongated" means a component having a length that is greater than (e.g., twice as great as) both its width and thickness. The elongated magnetic flux concentrator segments can have any suitable cross-section. For example, the elongated magnetic flux concentrator segments can have a square, elliptical, rectangular, triangular, pentagonal, hexagonal, or similar cross-sectional shape, according to the desired shape of the resulting magnetic flux concentrator. The elongated magnetic flux concentrator segments can have a planar or flat cross-sectional area. The elongated magnetic flux concentrator segments can have an arcuate cross-section. This can be particularly beneficial when the inductor coil has a curved outer surface, e.g., when the inductor coil has a circular cross-section, as it allows the elongated magnetic flux concentrator segments to closely follow the outer shape of the inductor coil, reducing the overall dimensions of the inductor and the device itself.

[0034] When the plurality of magnetic flux concentrator segments are elongated and positioned around the magnetic flux concentrator, the elongated segments can be arranged such that their respective longitudinal axes are non-parallel. In a preferred embodiment, the plurality of elongated magnetic flux concentrator segments are arranged such that their longitudinal axes are substantially parallel. The plurality of elongated magnetic flux concentrator segments can be arranged such that their longitudinal axes have an angle with respect to the magnetic axis of the inductor coil, i.e., are non-parallel thereto. For example, the elongated segments can be arranged such that their respective longitudinal axes are non-parallel to each other and non-parallel to the magnetic axis.

[0035] In a preferred embodiment, the plurality of elongated magnetic flux concentrator segments are arranged such that their longitudinal axes are substantially parallel to the magnetic axis of the inductor coil.

[0036] A plurality of magnetic flux concentrator segments can be directly attached to the inductor coil, for example, using an adhesive. The inductor may further comprise one or more intermediate components between the inductor coil and the magnetic flux concentrator segments, whereby the segments are held in a predetermined position relative to the inductor coil. For example, the inductor may further comprise an outer sleeve surrounding the inductor coil to which the segments are attached. The outer sleeve may have several slots or depressions in which the segments are held. If the magnetic flux concentrator segment is annular, the depression may be annular and arranged to hold the annular segment.

[0037] When a plurality of magnetic flux concentrator segments are elongated and positioned around the magnetic flux concentrator, the inductor preferably further comprises an outer sleeve surrounding the inductor coil and having a plurality of longitudinal slots in which the elongated magnetic flux concentrator segments are held.

[0038] The elongated magnetic flux concentrator segments can be fixed in a predetermined position relative to the outer sleeve. For example, the segments can be attached to the outer sleeve using an adhesive.

[0039] The elongated flux concentrator segment is preferably slidably held in the longitudinal slot such that the longitudinal position of the elongated flux concentrator segment relative to the inductor coil can be selectively varied. This allows for further adjustment of the flux concentrator and can achieve a desired electromagnetic field within the chamber. The elongated flux concentrator segment can be slidably held in the longitudinal slot by one or more non-adhesive retaining means associated with each longitudinal slot and arranged to engage the outer surface of the elongated segment received in the slot to prevent radial withdrawal of the segment from the slot. For example, the outer sleeve may include one or more non-adhesive retaining means for each longitudinal slot in the form of retaining tabs or clips that extend partially across the width of the slot, or retaining strips that extend across the full width of the slot, which allow longitudinal movement of the segment relative to the outer sleeve while retaining the radial position of the segment relative to the outer sleeve.

[0040] The longitudinal slot preferably has a length greater than the length of the elongated segment. With this configuration, the segment can be supported by the slot even when its longitudinal position relative to the outer sleeve is varied. In other examples, the slots may be open at the ends, such that the segments can extend partially beyond the slots when their longitudinal positions are varied.

[0041] The elongated segments may have a substantially constant thickness along their respective lengths. In other examples, the thickness of the elongated segments may vary along their respective lengths. For example, the thickness of the segment may taper or decrease from the central portion of the segment towards one end or towards both ends. In a preferred embodiment, the elongated magnetic flux concentrator segments are wedge-shaped. This means that the thickness gradually decreases along the length of the segment from one end to the other. With this configuration, the level of electromagnetic field distortion provided by the magnetic flux concentrator can be varied by changing the longitudinal position of one or more of the elongated segments relative to the outer sleeve.

[0042] The elongated magnetic flux concentrator segments may be arranged on the outer sleeve such that they are separated from each other by gaps. In other examples, two or more of the magnetic flux concentrator segments may be in direct contact with one or both of the adjacent magnetic flux concentrator segments.

[0043] In any of the above embodiments, the inductor may be incorporated within the housing of the device. For example, the inductor coil and the magnetic flux concentrator may be molded into the material from which the housing is formed.

[0044] Preferably, the inductor further comprises an inner sleeve having an outer surface on which the inductor coil is supported. With this configuration, the inductor coil can be wound around the inner sleeve during assembly. The inner surface of the inner sleeve may define the sidewall of the chamber along at least a portion of the length of the chamber. The inner sleeve may be made of any suitable material such as plastic. The inner sleeve may form part of the device housing. The inner sleeve may be an individual component connected to the device housing. The inner sleeve may be removable from the device housing, thereby enabling, for example, the repair or replacement of the inductor assembly.

[0045] The inner sleeve preferably comprises at least one protrusion on its outer surface at one or both ends of the inductor coil for holding the inductor coil on the inner sleeve. The at least one protrusion prevents or reduces the movement of the inductor coil in the longitudinal axis direction with respect to the inner sleeve. The at least one protrusion is preferably provided on the inner sleeve at both ends of the inductor coil. The at least one protrusion may comprise a plurality of protrusions at either end of the inductor coil arranged, for example, in a pattern. The plurality of protrusions may comprise a single protrusion at either end of the inductor coil. The at least one protrusion may comprise a protrusion extending around the entire circumference of the inner sleeve at either end of the inductor coil.

[0046] The at least one protrusion extends radially from the outer surface. The at least one protrusion preferably extends above the outer surface by a distance greater than the thickness of the inductor coil. Thus, the at least one protrusion extends above the inductor coil, thereby preventing the movement of the inductor coil in the longitudinal axis direction beyond the at least one protrusion. When the inductor further comprises an outer sleeve to which a plurality of magnetic flux concentrator segments are connected, the at least one protrusion is preferably arranged to hold the outer sleeve in place. For example, the at least one protrusion preferably extends above the outer surface by a distance greater than the combined thickness of the inductor coil and the outer sleeve. Thus, the at least one protrusion can abut against either or both ends of both the outer sleeve and the inductor coil to prevent any movement in the longitudinal axis direction with respect to the inner sleeve.

[0047] The aerosol generating device is preferably portable. The aerosol generating device may be of a size comparable to that of a conventional cigar or cigarette. The overall length of the aerosol generating device may be between approximately 30 mm and approximately 150 mm. The outer diameter of the aerosol generating device may be between approximately 5 mm and approximately 30 mm.

[0048] The power source may be a battery such as a rechargeable lithium-ion battery. As another method, 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 accumulation of sufficient energy for one or more uses of the device. For example, the power source may have a capacity sufficient to allow for the continuous generation of aerosol for about six minutes, or a multiple of six minutes, corresponding to the typical time taken to smoke one conventional cigarette. In another example, the power source may have a capacity sufficient to allow for a predetermined number of puffs, or discontinuous activations.

[0049] The aerosol generating device may further comprise an electronic device configured to control the power supply from the power source to the inductor. The electronic device may be configured to disable the operation of the device by blocking the power supply to the inductor, or may be configured to enable the operation of the device by allowing the power supply to the inductor.

[0050] The device may comprise one or more susceptor elements within the chamber, which are arranged to heat the aerosol-forming substrate of the aerosol-generating article received in the chamber. For example, the device may comprise one or more susceptor elements formed in the same manner as those described below in relation to the aerosol-generating article. The device may comprise one or more external susceptor elements that remain external to the aerosol-generating article received in the recess and are configured to heat the aerosol-forming substrate of the aerosol-generating article when activated by an inductor coil. For example, one or more external susceptor elements may at least partially extend around the aerosol-generating article. The device may comprise one or more internal susceptor elements that at least partially extend within the aerosol-generating article received in the recess and are configured to heat the aerosol-forming substrate of the aerosol-generating article when activated by an inductor coil. For example, one or more internal susceptor elements may be arranged to penetrate the aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received in the chamber. One or more susceptor elements may comprise susceptor blades within the chamber. The device may comprise one or more external susceptor elements and one or more internal susceptor elements as described above.

[0051] If the device comprises one or more susceptor elements within the chamber, the one or more susceptor elements may be attached to the device. The one or more susceptor elements may be removable from the device. This may allow the one or more susceptor elements to be replaced independently of the device. For example, the one or more susceptor elements may be removable as one or more individual components or as part of a removable inductor assembly. The device may comprise a plurality of susceptor elements within the chamber. The plurality of susceptor elements within the chamber may be fixed within the chamber. One or more of the plurality of susceptor elements may be removable from the device such that they may be replaced. The plurality of susceptor elements may be removable individually or together with one or more of the other susceptor elements.

[0052] The device housing may be elongated. The housing may comprise any suitable material or combination of materials. Suitable materials include, for example, metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications such as, for example, polypropylene, polyetheretherketone (PEEK), and polyethylene. The material is preferably lightweight and not brittle.

[0053] The device housing may comprise a mouthpiece. The mouthpiece may comprise at least one air inlet and at least one air outlet. The mouthpiece may comprise two or more air inlets. One or more of the air inlets can reduce the temperature of the aerosol before it is delivered to the user and can reduce its concentration before it is delivered to the user. As used herein, the term "mouthpiece" refers to the part of an aerosol generating device that is placed in the user's mouth to directly inhale the aerosol generated by the aerosol generating device from an aerosol generating article received in a chamber of the housing.

[0054] The aerosol generating device may include a user interface for activating the device, such as a button to start heating the device, or a display indicating the state of the device or the aerosol forming substrate.

[0055] According to a second aspect of the invention, there is provided an electrically operated aerosol generating system comprising an electrically operated aerosol generating device according to any of the above embodiments, an aerosol generating article comprising an aerosol forming substrate, and a susceptor element positioned to heat the aerosol forming substrate during use, wherein the aerosol generating article is at least partially received in and disposed within a chamber such that the susceptor element is inductively heatable by an inductor of the aerosol generating device, thereby heating the aerosol forming substrate of the aerosol generating article received in the chamber.

[0056] The aerosol-forming substrate preferably comprises a tobacco-containing material containing volatile tobacco flavor compounds released from the aerosol-forming substrate upon heating. However, the aerosol-forming substrate may contain non-tobacco materials. The aerosol-forming substrate may further comprise an aerosol former that promotes the formation of a high-density and stable aerosol. As used herein, the term "aerosol former" is used to describe any suitable known compound or mixture of compounds that promotes the formation of an aerosol during use. Suitable aerosol formers are preferably substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating article. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0057] The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components.

[0058] In a particularly preferred embodiment, the aerosol-forming substrate comprises an assembly of crimped sheets of homogenized tobacco material. As used herein, the term "crimped sheet" means a sheet having a plurality of substantially parallel ridges or wrinkles.

[0059] The aerosol-generating article may comprise a susceptor element positioned to heat the aerosol-forming substrate during use. The susceptor element is a conductor that can be inductively heated. The susceptor element can absorb electromagnetic energy and convert it into heat. During use, the susceptor element is heated by changing the electromagnetic field generated by the inductor coil, which then transfers heat to the aerosol-forming substrate of the aerosol-forming article mainly by conduction. The susceptor element may be configured to heat the aerosol-forming substrate by at least one of conductive heat transfer, convective heat transfer, radiative heat transfer, and combinations thereof. For this purpose, the susceptor is in thermal proximity to the material of the aerosol-forming substrate. The form, type, distribution, and arrangement of the susceptor can be selected according to the needs of the user.

[0060] The susceptor element can have a length dimension that is greater than its width dimension or its thickness dimension, for example greater than twice its width dimension or its thickness dimension. Thus, the susceptor element can be depicted as an elongated susceptor element. The susceptor element is disposed substantially in the longitudinal direction within the rod. This means that the length dimension of the elongated susceptor element is disposed substantially parallel to the longitudinal axis of the rod, for example within ±10 degrees parallel to the longitudinal axis of the rod. In a preferred embodiment, the elongated susceptor element may be located at a radially central position within the rod and extends along the longitudinal axis of the rod.

[0061] The susceptor element is preferably in the form of a pin, rod, blade or plate. The susceptor element is preferably 5 mm to 15 mm in length, for example 6 mm to 12 mm, or 8 mm to 10 mm. The susceptor element preferably has a width of 1 mm to 5 mm and preferably has a thickness of 0.01 mm to 2 mm, for example 0.5 mm to 2 mm. A preferred embodiment can have a thickness of 10 micrometers to 500 micrometers, but is even more preferably 10 to 100 micrometers. If the susceptor element has a constant cross-section, such as a circular cross-section, the preferred width or diameter can be 1 mm to 5 mm.

[0062] The susceptor element can be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptor elements contain metal or carbon. Preferred susceptor elements can include ferromagnetic materials, such as ferrite iron, or ferromagnetic steel or stainless steel. A suitable susceptor element can be aluminum or can contain aluminum. Preferred susceptor elements can be formed from 400 series stainless steels, such as grade 410, or grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when positioned within an electromagnetic field having similar values of frequency and magnetic field strength. Thus, any of the parameters of the susceptor element, such as the type of material, length, width, and thickness, can be varied to provide the desired power dissipation within a known electromagnetic field.

[0063] A preferred susceptor element can be heated to a temperature exceeding 250 degrees Celsius. A suitable susceptor element can comprise a non-metallic core with a metal layer, such as a metal strip, disposed on the surface of a ceramic core.

[0064] The susceptor element may have a protective outer layer enclosing the susceptor element, such as a protective ceramic layer or a protective glass layer. The susceptor element can comprise a protective coating formed of glass, ceramic, or an inert metal, formed on top of the core of the susceptor material.

[0065] The susceptor element is disposed in thermal contact with the aerosol-forming substrate. Thus, when the temperature of the susceptor element increases, the aerosol-forming substrate is heated and an aerosol is formed. The susceptor element is preferably disposed in physical direct contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0066] The aerosol-generating article can include a single susceptor element. Alternatively, the aerosol-generating article can comprise two or more elongated susceptor elements.

[0067] The aerosol-generating article and the chamber of the device can be arranged such that the article is partially received within the chamber of the aerosol-generating device. The chamber of the device and the aerosol-generating article can be arranged such that the article is entirely received within the chamber of the aerosol-generating device.

[0068] The aerosol-generating article can have a substantially cylindrical shape. The aerosol-generating article can be substantially elongated. The aerosol-generating article can also have a length and a perimeter substantially orthogonal to the length. The aerosol-forming substrate can be provided as an aerosol-forming segment comprising the aerosol-forming substrate. The aerosol-forming segment can have a substantially cylindrical shape. The aerosol-forming segment can be substantially elongated. The aerosol-forming segment can have a length and a perimeter substantially orthogonal to the length.

[0069] The overall length of the aerosol-generating article can be approximately 30 mm to approximately 100 mm. In one embodiment, the overall length of the aerosol-generating article is approximately 45 mm. The outer diameter of the aerosol-generating article may be approximately 5 mm to approximately 12 mm. In one embodiment, the aerosol-generating article can have an outer diameter of approximately 7.2 mm.

[0070] The aerosol-forming substrate can be provided as an aerosol-forming segment having a length of about 7 mm to about 15 mm. In one embodiment, the aerosol-forming segment can have a length of approximately 10 mm. Alternatively, the aerosol-forming segment can have a length of approximately 12 mm.

[0071] The aerosol-generating segment preferably has an outer diameter substantially equal to the outer diameter of the aerosol-generating article. The outer diameter of the aerosol-forming segment may be approximately 5 mm to approximately 12 mm. In one embodiment, the aerosol-forming segment can have an outer diameter of approximately 7.2 mm.

[0072] The aerosol-generating article can include a filter plug. The filter plug can be located at the downstream end of the aerosol-generating article. The filter plug may be a cellulose acetate filter plug. In one embodiment, the length of the filter plug is approximately 7 mm, but can also be approximately 5 mm to approximately 10 mm.

[0073] The aerosol-generating article can include an outer paper wrapper. Further, the aerosol-generating article may include a separation portion between the aerosol-forming substrate and the filter plug. The separation portion may be approximately 18 mm, but can also be in the range of approximately 5 mm to approximately 25 mm.

[0074] 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. However, the aerosol generating system may include additional components, such as a charging unit for electrically operating or recharging an on-board power supply within an electric aerosol generating device.

[0075] The aerosol generating device includes an inductor comprising an inductor coil and a magnetic flux concentrator disposed around the inductor coil. The inductor may be an integral part of the aerosol generating device. The inductor may be a separate component removable from other parts of the aerosol generating device. This allows the inductor to be replaced independently of the remaining components of the aerosol generating device.

[0076] According to a third aspect of the present invention, there is provided an inductor assembly for an electrically operated aerosol generating device, the inductor assembly defining a chamber for receiving at least a portion of an aerosol generating article, an inductor coil disposed around at least a portion of the chamber, and a magnetic flux concentrator disposed around the inductor coil and configured to distort a variable electromagnetic field generated by the inductor coil towards the chamber during use, the magnetic flux concentrator comprising a plurality of individual magnetic flux concentrator segments positioned adjacent to each other.

[0077] There is also provided a kit comprising an aerosol generating device according to a first aspect of the present invention and a plurality of inductor assemblies according to a third aspect of the present invention.

[0078] According to a fourth aspect of the present invention, there is provided an electrically operated aerosol generating device for heating an aerosol generating article comprising an aerosol forming substrate by heating a susceptor element positioned to heat the aerosol forming substrate. The device comprises a device housing defining a chamber for receiving at least a portion of the aerosol generating article, an inductor comprising an inductor coil disposed around at least a portion of the chamber, and a power supply connected to the inductor coil and configured to provide a high-frequency current to the inductor coil such that, in use, the inductor coil generates a varying electromagnetic field to heat the susceptor element and thereby heat the aerosol forming substrate. The inductor further comprises a magnetic flux concentrator disposed around the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil towards the chamber in use, and the inductor further comprises a buffer element positioned between the magnetic flux concentrator and the device housing.

[0079] As used herein, the term "buffer element" refers to an elastic component configured to be deformed during a collision to absorb kinetic energy and thereby reduce the intensity of the impact transmitted by the device housing to the magnetic flux concentrator during the collision.

[0080] This configuration reduces the risk of breakage of the magnetic flux concentrator during manufacture, transportation, operation and use. Furthermore, it may be possible to reduce the thickness of the magnetic flux concentrator. Reducing the thickness of the magnetic flux concentrator can make it possible to reduce the overall size and weight of the aerosol generating device, and can make it possible for such devices to be manufactured more cost-effectively and with less raw material usage.

[0081] The buffer element may comprise a single component or a plurality of individual buffer elements. The buffer element may comprise a plurality of individual buffer elements arranged at regular intervals around the magnetic flux concentrator. The buffer element may comprise a plurality of individual buffer elements arranged at regular intervals along the length of the magnetic flux concentrator.

[0082] In certain embodiments, the buffer element extends substantially around the entire circumference of the magnetic flux concentrator. The term "substantially around the entire circumference of the magnetic flux concentrator" means at least 90 percent, preferably at least 95 percent, more preferably at least 97 percent of the outer circumference of the magnetic flux concentrator. In such embodiments, the buffer element may comprise one or more elastic o-rings extending around the outer circumference of the magnetic flux concentrator.

[0083] In a preferred embodiment, the buffer element is adhered substantially over the entire outer surface of the magnetic flux concentrator. The term "substantially over the entire outer surface of the magnetic flux concentrator" refers to at least 90 percent, preferably at least 95 percent, more preferably at least 97 percent of the outer surface area of the magnetic flux concentrator.

[0084] This configuration can avoid relative movement between the magnetic flux concentrator and the buffer element to ensure proper performance of the buffer element. Further, by adhering the buffer element to the magnetic flux concentrator, the performance of the magnetic flux concentrator can be maintained even if the magnetic flux concentrator accidentally breaks during a collision. This is because the broken piece of the magnetic flux concentrator is held by the buffer element at substantially the same position as before breaking.

[0085] In a particularly preferred embodiment, the magnetic flux concentrator is encapsulated within a buffer element. As used herein, the term "encapsulated" means that the magnetic flux concentrator is enclosed within the buffer element in a close relationship such that relative movement between the magnetic flux concentrator and the buffer element is substantially prevented. This configuration has been found to provide a specific protective environment for the magnetic flux concentrator.

[0086] The magnetic flux concentrator may be in direct contact with the buffer element or may be in indirect contact via one or more intermediate layers. For example, if the aerosol generating device or inductor assembly according to the present invention comprises a conductive shield disposed around the magnetic flux concentrator, the buffer element may be in contact with the magnetic flux concentrator via the conductive shield. In other words, when the inductor is mounted within the aerosol generating device, the buffer element is disposed between the device housing and both the magnetic flux concentrator and the conductive shield.

[0087] The buffer element may be formed from any suitable single elastic material or a plurality of elastic materials.

[0088] In certain embodiments, the buffer element is formed from one or more of silicone, epoxy resin, rubber or another elastomer.

[0089] According to a fifth aspect of the present invention, there is provided an electrically operated aerosol generating system comprising an electrically operated aerosol generating device according to any of the above-described embodiments related to the fourth aspect of the present invention, an aerosol generating article comprising an aerosol forming substrate, and a susceptor element positioned to heat the aerosol forming substrate during use, wherein the aerosol generating article is at least partially received within and disposed within a chamber such that the susceptor element is inductively heatable by an inductor of the aerosol generating device, thereby heating the aerosol forming substrate of the aerosol generating article received within the chamber.

[0090] According to a sixth aspect of the present invention, there is provided an inductor assembly for an electrically operated aerosol generator, the inductor assembly defining a chamber for receiving at least a portion of an aerosol generating article, an inductor coil disposed around at least a portion of the chamber, and a magnetic flux concentrator disposed around the inductor coil and configured to distort a variable electromagnetic field generated by the inductor coil during use towards the chamber, and a buffer element positioned on an outer surface of the magnetic flux concentrator.

[0091] The buffer element may comprise a single component or a plurality of individual buffer elements. The buffer element may comprise a plurality of individual buffer elements arranged at regular intervals around the magnetic flux concentrator. The buffer element may comprise a plurality of individual buffer elements arranged at regular intervals along the length of the magnetic flux concentrator.

[0092] In certain embodiments, the buffer element extends substantially around the entire circumference of the magnetic flux concentrator. In such embodiments, the buffer element may comprise one or more elastic o-rings extending around the outer circumference of the magnetic flux concentrator. In a preferred embodiment, the buffer element is substantially adhered to the entire outer surface of the magnetic flux concentrator. In a particularly preferred embodiment, the magnetic flux concentrator is encapsulated within the buffer element.

[0093] There is also provided a kit comprising an aerosol generator according to a fourth aspect of the present invention and a plurality of inductor assemblies according to a sixth aspect of the present invention.

[0094] According to a seventh aspect of the present invention, there is provided an electrically operated aerosol generating device for heating an aerosol generating article comprising an aerosol forming substrate by heating a susceptor element positioned to heat the aerosol forming substrate. The device comprises a device housing defining a chamber for receiving at least a portion of the aerosol generating article, an inductor comprising an inductor coil disposed around at least a portion of the chamber, and a power supply connected to the inductor coil and configured to provide a high-frequency current to the inductor coil such that, in use, the inductor coil generates a varying electromagnetic field to heat the susceptor element and thereby heat the aerosol forming substrate. The inductor further comprises a magnetic flux concentrator disposed around the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil during use towards the chamber. The inductor further comprises a conductive shield disposed around the magnetic flux concentrator.

[0095] The conductive shield is configured to change the direction of the electromagnetic field in a direction opposite to the region of the inductor outside the shield.

[0096] With this configuration, the shield functions to reduce the distortion of the electromagnetic field by a conductive or highly magnetically sensitive material in the immediate vicinity of the device or in the housing of the device itself. This may enable the electromagnetic field generated by the inductor coil to be more uniform. Further, it may enable the inductor to be calibrated with respect to a constant desired level of performance without the need to consider the material from which the outer housing of the device is made. For example, a metal shield may enable an inductor of the same configuration to produce substantially the same results whether used in a device having a plastic housing or a device having a metal housing. In other words, the provision of the conductive shield means that the influence of the device housing based on the electromagnetic field generated by the inductor coil is minimal.

[0097] The shield may comprise or be formed from any suitable conductive material. For example, the shield can be formed from a conductive polymer. The conductive shield may be a metal shield. For example, the conductive shield may be a metal foil extending around the magnetic flux concentrator. The shield may be a conductive coating applied to a component extending around the magnetic flux concentrator. For example, the shield may be a metal coating applied to the surface of a non-metallic sleeve extending around the magnetic flux concentrator. The metal coating can be applied in any suitable manner, such as by a metal paint, metal ink, or a vapor deposition process. In a preferred embodiment, the conductive shield is applied to the outer surface of the magnetic flux concentrator as a conductive foil, a conductive coating, or both.

[0098] The shield is preferably formed from a material having a relative permeability of at least 5, preferably at least 20, at a frequency of 6 - 8 MHz and a temperature of 25 degrees Celsius.

[0099] The shield has a -2 specific resistance of at least 1 x 10 -4 Ωm, preferably at least 1 x 10 -6 Ωm, and more preferably at least 1 x 10

[0100] Suitable materials for the shield include aluminum, copper, tin, steel, gold, silver, or any combination thereof. The shield preferably includes aluminum or copper.

[0101] According to an eighth aspect of the present invention, there is provided an electrically operated aerosol generating device according to any of the above-described embodiments related to the fourth aspect of the present invention, an aerosol generating article including an aerosol forming substrate, and a susceptor element positioned to heat the aerosol forming substrate during use, wherein the aerosol generating article is at least partially received in and disposed within a chamber such that the susceptor element is inductively heatable by an inductor of the aerosol generating device, thereby heating the aerosol forming substrate of the aerosol generating article received in the chamber. An electrically operated aerosol generating system is provided.

[0102] According to a ninth aspect of the present invention, there is provided an inductor assembly for an electrically operated aerosol generating device, the inductor assembly defining a chamber for receiving at least a portion of an aerosol generating article, an inductor coil disposed around at least a portion of the chamber, and a magnetic flux concentrator disposed around the inductor coil and configured to distort a varying electromagnetic field generated by the inductor coil during use towards the chamber, and a conductive shield disposed around the magnetic flux concentrator, wherein the shield is configured to change the direction of the electromagnetic field in a direction opposite to an outer region of the inductor assembly.

[0103] There is also provided a kit comprising an aerosol generating device according to the seventh aspect of the present invention and a plurality of inductor assemblies according to the ninth aspect of the present invention.

[0104] The features described in relation to one or more aspects may equally apply to other aspects of the present invention. Specifically, the features described in relation to the device of the first aspect may equally apply to the devices of the fourth and seventh aspects, the systems of the second, fifth and eighth aspects, and the inductor assemblies of the third, sixth and ninth aspects, and vice versa.

[0105] The present invention will be further described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0106]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0107] Figure 1 shows a schematic cross-sectional view of an electrically actuated aerosol generator 100 and an aerosol article 10 that together form an electrically actuated aerosol generation system. The electrically actuated aerosol generator 100 includes a device housing 110 that defines a chamber 120 for receiving the aerosol article 10. The proximal end of the housing 110 has an insertion opening 130 through which the aerosol article 10 can be inserted into and removed from the chamber 120. An inductor 200 is disposed inside the device 100 between the outer wall of the housing 110 and the chamber 120. The inductor 200 includes a helical inductor coil that corresponds to the longitudinal axis of the chamber 120, which also corresponds to the longitudinal axis of the device 100 in this embodiment, and has a magnetic axis. As shown in Figure 1, the inductor 200 is positioned adjacent to the distal portion of the chamber 120 and, in this embodiment, extends along a portion of the length of the chamber 120. In other embodiments, the inductor 200 may extend along the entire length, or substantially the entire length, of the chamber 120, or may extend along a portion of the length of the chamber 120 and be positioned, for example, adjacent to the proximal portion of the chamber 120 and away from the distal portion of the chamber 120. The inductor 200 is further described below in connection with Figure 2.

[0108] The device 100 also includes an internal power source 140 (e.g., a rechargeable battery, etc.) and an electronic device 150 (e.g., a printed circuit board with circuits, etc.) that are both located in the distal region of the housing 110. Both the electronic device 150 and the inductor 200 receive power from the power source 140 via an electrical connection (not shown) that extends through the housing 110. The chamber 120 is preferably separated from the inductor 200 and the distal region of the housing 110 that includes the power source 140 and the electronic device 150 by a liquid-tight separation. Thus, the electrical components within the device 100 can remain separated from the aerosol or residues generated within the chamber 120 by the aerosol generation process. This can also facilitate the cleaning of the device 100 since the chamber 120 can be completely empty when no aerosol-generating article is present. Further, since potential breakable elements are not exposed within the chamber 120, the risk of damage to the device during either the insertion of the aerosol-generating article or during cleaning can be reduced. A ventilation hole (not shown) may be provided in the wall of the housing 110, which allows air flow into the chamber 120.

[0109] The aerosol-forming article 10 includes, for example, an aerosol-forming segment 20 that houses an aerosol-forming substrate, such as a plug that includes a tobacco material and an aerosol former, and a susceptor element 30 for heating the aerosol-forming substrate 20. As shown in FIG. 1, the susceptor 30 is disposed within the aerosol-generating article such that it can be inductively heated by the inductor 200 when the aerosol-generating article 10 is received in the chamber 120.

[0110] When device 100 operates, a high-frequency alternating current passes through the inductor coil of inductor 200. Thereby, inductor 200 generates a fluctuating electromagnetic field within the distal portion of chamber 120 of device 100. The frequency of the electromagnetic field preferably varies from 1 to 30 MHz, preferably from 2 to 10 MHz, for example from 5 to 7 MHz. When the aerosol-generating article 10 is correctly positioned within chamber 120, susceptor 30 of article 10 is located within this fluctuating electromagnetic field. The fluctuating electromagnetic field generates eddy currents within susceptor 30, as a result of which it is heated. Further heating is provided by magnetic hysteresis losses within susceptor 30. The heated susceptor 30 heats the aerosol-forming substrate 20 of the aerosol-generating article 10 to a temperature sufficient to form an aerosol. The aerosol is drawn downstream through the aerosol-generating article 10 and can be inhaled by the user. Such operation may be manual or may occur automatically in response to the user inhaling the aerosol-generating article 10.

[0111] Referring to FIGS. 2 and 3, inductor 200 is tubular and comprises a cylindrical inductor coil 210 wound in a helical manner surrounding an inner tubular sleeve 220. Both the inductor coil 210 and the inner sleeve 220 are surrounded by a tubular magnetic flux concentrator 230 extending along the length of the inductor coil 210. Inductor 200 may further include a cushioning element (not shown) in which the magnetic flux concentrator 230 is enclosed to provide impact resistance to the magnetic flux concentrator. The cushioning element is in the form of a silicone rubber sleeve in which the magnetic flux concentrator is held. Inductor 200 may further include a conductive shield (not shown) disposed around the magnetic flux concentrator 230 and further enclosed within the cushioning element. The shield is configured to change the direction of the electromagnetic field in the opposite direction of the region outside the inductor 200. The conductive shield is provided as a metal coating adhered onto the outer surface of the magnetic flux concentrator such that it extends through substantially the entire outer surface of the magnetic flux concentrator.

[0112] The inductor coil 210 is formed from a wire 212 and has a plurality of turns or windings extending along its length. The wire 212 can have any suitable cross-sectional shape, such as square, elliptical, or triangular. In this embodiment, the wire 212 has a circular cross-sectional shape. In other embodiments, the wire can have a flat cross-sectional shape. For example, the inductor coil can be formed from a wire having a rectangular cross-sectional shape and wound such that the maximum width of the cross-section of the wire extends parallel to the magnetic axis of the inductor coil. Such flat inductor coils can make it possible to minimize the outer diameter of the inductor and thus the outer diameter of the device.

[0113] The inner sleeve 220 has an outer surface 222 on which the inductor coil is disposed and an inner surface 224. The inner surface 224 defines the side wall of the chamber of the device in the distal region of the chamber. In this way, the inductor coil 210 surrounds the chamber along at least a portion of its length. The outer surface 222 has a pair of annular protrusions 226 extending around the inner sleeve 220. The protrusions 226 are located at either end of the inductor coil 210 and hold the coil 210 in place on the inner sleeve 220. The inner sleeve can be made of any suitable material, such as plastic.

[0114] The magnetic flux concentrator 230 is attached around the inductor coil 210 and held in place by the protrusions 226 on the outer surface 222 of the sleeve 220. The magnetic flux concentrator 230 is formed from a material having a high relative permeability, such that the electromagnetic field generated by the inductor coil 210 is attracted to and guided by the magnetic flux concentrator 230. This is shown with reference to FIG. 4A, which shows the electromagnetic field lines generated by the upper portion of the inductor 200 of the first embodiment, and FIG. 4B, which shows the electromagnetic field lines generated by the upper portion of a prior art inductor 400 having an inductor coil 410 but no magnetic flux concentrator. Comparing FIGS. 4A and 4B, it can be seen that the electromagnetic field is distorted by the magnetic flux concentrator 230, such that the electromagnetic field lines do not propagate beyond the outer diameter of the inductor 200 to the same extent as in the inductor 400 of FIG. 4B. Thus, the magnetic flux concentrator 230 serves as a magnetic shield. This can reduce unwanted heating of, or interference with, external objects as compared to the prior art inductor 400. The electromagnetic field lines within the internal volume defined by the inductor 200 are also distorted by the magnetic flux concentrator such that the density of the electromagnetic field within the chamber is increased. This can increase the current generated within a susceptor placed within the chamber. In this way, the electromagnetic field is concentrated towards the chamber, thereby enabling more efficient heating of the susceptor.

[0115] The magnetic flux concentrator 230 may be made of any suitable single or plurality of materials having a high relative permeability. For example, the magnetic flux concentrator may be formed from one or more ferromagnetic materials (such as ferrite materials, ferrite powder held in a binder, etc.), or any other suitable material including a ferrite material such as ferrite iron, ferromagnetic steel or stainless steel.

[0116] The magnetic flux concentrator is preferably made of a single material or a plurality of materials having a high relative permeability. It is a material having a relative permeability of at least 5 (for example, at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 80 or at least 100) when measured at 25 degrees Celsius. These exemplary values can mean the relative permeability of the magnetic flux concentrator material for a frequency of 6 to 8 MHz and a temperature of 25 degrees Celsius. In this embodiment, the magnetic flux concentrator is a single component. In other embodiments, the magnetic flux concentrator can be formed from a layer of sheet material or a plurality of individual segments as described below in connection with FIGS. 5-9. In this example, the thickness of the magnetic flux concentrator is substantially constant along its length and is selected based on the material used for the magnetic flux concentrator and the amount of electromagnetic field distortion required. For example, when the magnetic flux concentrator is made of ferrite, its thickness can range from 0.3 mm to 5 mm, preferably from 0.5 mm to 1.5 mm.

[0117] FIG. 5 and FIG. 6 show an inductor 500 according to a second embodiment. The inductor 500 of the second embodiment is similar to the first embodiment of the inductor 200 shown in FIGS. 1 to 4A in terms of structure and operation, and like reference numerals are used where the same features exist. However, unlike the inductor 200 of the first embodiment, in the inductor 500 of the second embodiment, the magnetic flux concentrator 530 is not a single component. Instead, it is formed from a plurality of magnetic flux concentrator segments 531, 532, 533, 534, 535 that are positioned adjacent to each other. The magnetic flux concentrator segments 531, 532, 533, 534, 535 are tubular and are coaxially positioned along the length of the magnetic flux concentrator 530. In this example, the magnetic flux concentrator segments have an annular cylindrical shape. As a result, the magnetic flux concentrator 530 also has an annular cylindrical shape. However, of course, other shapes may be achieved by selecting different shapes for one or more of the magnetic flux concentrator segments. In this example, the magnetic flux concentrator segments are positioned directly adjacent to each other such that they are in abutting coaxial arrangement. In other examples, two or more of the magnetic flux concentrator segments may be separated from adjacent magnetic flux concentrator segments by a gap.

[0118] Advantageously, the use of individual flux concentrator segments to form the flux concentrator 530 allows the flux concentrator to be assembled using different segments having different relative permeability values. For example, the flux concentrator can be formed from one or more flux concentrator segments made of a first material having a first relative permeability and one or more flux concentrator segments made of a second material having a second relative permeability. This allows the flux concentrator to be "finely tuned" during assembly, thereby achieving a desired level of induction from the inductor coil and a desired level of electromagnetic flux within the chamber in which the susceptor of the aerosol generating article is positioned during use. Each of the flux concentrator segments can be made from different materials, or the same material, or any number of combinations thereof.

[0119] Similar to the inductor 200 of the first embodiment, the inductor 500 includes an inner sleeve 520 having a plurality of protrusions 526 on its outer surface 522 by which the inductor coil 510 and the flux concentrator 530 are held in place.

[0120] Furthermore, similar to the inductor 200 of the first embodiment, the inductor 500 may further include a buffer element (not shown) in which individual segments of the flux concentrator 530 are encapsulated, thereby providing shock resistance to the flux concentrator, and may further include a conductive shield disposed around the flux concentrator 530 and configured to change the direction of the electromagnetic field in the opposite direction of the region external to the inductor 500. As the flux concentrator 530 is provided as a plurality of individual segments, so too are the conductive shield and the buffer element. This allows the flux concentrator to be finely tuned by replacing the flux concentrator segments together with their corresponding conductive shield segments and buffer element segments.

[0121] Figures 7 to 9 show an inductor 700 according to a third embodiment. The inductor 700 of the third embodiment is similar to the first and second embodiments of the inductor shown in FIGS. 1 to 6 in terms of structure and operation, and similar reference numerals are used when there are identical features. Similar to the inductor 500 of the second embodiment, the magnetic flux concentrator 730 is not a single component, but instead is formed from a plurality of magnetic flux concentrator segments 731, 732, 733, 734, 735 that are positioned adjacent to each other. Different from the magnetic flux concentrator 530 of the second embodiment, the magnetic flux concentrator segments 731, 732, 733, 734, 735 are elongated and are positioned around the magnetic flux concentrator 730 such that their longitudinal axes are substantially parallel to the magnetic axis of the inductor coil 710. The magnetic flux concentrator 730 further includes an outer sleeve 736 that surrounds the inductor coil 710 and is used to hold the magnetic flux concentrator segments in place. To achieve this purpose, the outer sleeve 736 includes a plurality of longitudinal slots 737 in which the magnetic flux concentrator segments are slidably held. In this embodiment, the outer sleeve 736 has an annular cylindrical shape, and the magnetic flux concentrator segments have an arcuate cross-section corresponding to the outer shape of the outer sleeve. As a result, the magnetic flux concentrator 730 also has an annular cylindrical shape. However, of course, other shapes may be achieved by selecting different shapes for the outer sleeve and the magnetic flux concentrator segments. The longitudinal slots 737 have a length greater than the length of the magnetic flux concentrator segments. As a result, each of the magnetic flux concentrator segments can slide within their respective slots 737, thereby staying within their respective slots while changing their respective longitudinal positions. This enables the electromagnetic field to be adjusted by changing the longitudinal position of one or more of the elongated magnetic flux concentrator segments. In this embodiment, the elongated magnetic flux concentrator segments have a substantially constant thickness. In other embodiments, the elongated magnetic flux concentrator segments may be wedge-shaped.That is, the thickness of each of the magnetic flux concentrator segments can increase along its length from one end to the other. This allows for further adjustment of the electromagnetic field by adjusting the longitudinal position of one or more of the elongated magnetic flux concentrator segments within their respective slots according to a desired level of induction.

[0122] In this example, the elongated magnetic flux concentrator segments are disposed on the outer sleeve 736 such that they are separated by a narrow gap 738. In other examples, two or more of the magnetic flux concentrator segments can be in direct contact with one or both of the magnetic flux concentrator segments at any of their sides.

[0123] Similar to the inductors 200, 500 of the first and second embodiments, the inductor 700 includes an inner sleeve 720 having a plurality of protrusions 726 on its outer surface 722 by which the inductor coil 710 and the magnetic flux concentrator 730 are held in place. The protrusions 726 are positioned on both sides of the inductor coil 710 and the outer sleeve 736 and hold the magnetic flux concentrator 730 in place by preventing longitudinal movement of the outer sleeve 736.

[0124] Further, similar to the inductor 200 of the first and second embodiments, the inductor 700 may further include a cushioning element (not shown) in which individual segments of the magnetic flux concentrator 570 are encapsulated, thereby providing impact resistance to the magnetic flux concentrator, disposed around the magnetic flux concentrator 730, and may further include a conductive shield configured to change the direction of the electromagnetic field in the opposite direction of the region external to the inductor 700. As the magnetic flux concentrator 730 is provided as a plurality of individual segments, so are the conductive shield and the cushioning element. This allows for fine adjustment of the magnetic flux concentrator by replacing the magnetic flux concentrator segments together with their corresponding conductive shield segments and cushioning element segments.

[0125] The use of individual magnetic flux concentrator segments to form the magnetic flux concentrator 730 allows the magnetic flux concentrator to be assembled using different segments having different relative permeability values. For example, the magnetic flux concentrator can be formed from one or more elongated magnetic flux concentrator segments made of a first material having a first relative permeability and one or more elongated magnetic flux concentrator segments made of a second material having a second relative permeability. This allows the magnetic flux concentrator to be "finely tuned" during assembly, thereby achieving a desired level of induction from the inductor coil and a desired level of electromagnetic flux within the chamber in which the susceptor of the aerosol-generating article is positioned during use. To achieve this purpose, each of the elongated magnetic flux concentrator segments can be made from different materials, or the same material, or any number of combinations thereof.

[0126] It is not intended to limit the claims by the above exemplary embodiments. Other embodiments consistent with the above exemplary embodiments will be apparent to those skilled in the art.

[0127] For example, in the above embodiments, the inductor comprises an inner sleeve that forms the side wall of the chamber around which the inductor coil is wound. In such embodiments, the tubular sleeve may be an integral part of the housing or may be removable from the housing together with other parts of the inductor. In other embodiments, the inductor coil and the magnetic flux concentrator may be molded, for example, into the material from which the housing is formed and incorporated within the housing of the device. In such embodiments, an inner sleeve is not required.

[0128] In the above-described embodiment, the magnetic flux concentrator in each case is generally a cylindrical annular portion. That is, the magnetic flux concentrator has a circular cross-section and a substantially uniform thickness along its length. However, it will be understood that the magnetic flux concentrator may have any suitable shape, which may depend, for example, on the shape of the inductor coil and the desired electromagnetic field shape. For example, the magnetic flux concentrator may have a square, elliptical, or rectangular cross-section. The magnetic flux concentrator may also vary in thickness along its length or around its circumference. For example, the thickness of the magnetic flux concentrator may taper uniformly towards one or both of its ends.

[0129] Furthermore, the magnetic flux concentrator has been described as being formed as a single component or from a plurality of tubular magnetic flux concentrator segments or elongated magnetic flux concentrator segments. However, it will be understood that the magnetic flux concentrator segments may have any suitable shape or configuration. For example, the magnetic flux concentrator may comprise a combination of both elongated magnetic flux concentrator segments and tubular magnetic flux concentrator segments.

Claims

1. An electrically operated aerosol generating device for heating an aerosol generating article comprising an aerosol forming substrate by heating a susceptor element positioned to heat the aerosol forming substrate, a device housing defining a chamber for receiving at least a portion of the aerosol generating article, an inductor comprising an inductor coil disposed around at least a portion of the chamber, a power supply connected to the inductor coil and configured to provide a high-frequency current to the inductor coil such that, in use, the inductor coil generates a varying electromagnetic field to heat the susceptor element and thereby heat the aerosol forming substrate, the inductor further comprising a magnetic flux concentrator arranged around the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil towards the chamber during use, the inductor further comprising a conductive shield arranged around the magnetic flux concentrator, the inductor further comprising an inner sleeve having an outer surface on which the inductor coil is supported, the inner sleeve comprising protrusions on its outer surface at one or both ends of the inductor coil for holding the inductor coil on the inner sleeve, an electrically operated aerosol generating device.

2. The electrically operated aerosol generating device according to claim 1, wherein the conductive shield is a metal foil extending around the magnetic flux concentrator or a metal coating applied to a component extending around the magnetic flux concentrator.

3. The electrically operated aerosol generating device according to claim 1 or 2, wherein the conductive shield is formed from a material having a relative permeability of at least 5 at a frequency of 6 to 8 MHz and a temperature of 25 degrees Celsius.

4. The electrically operated aerosol generating device according to any one of claims 1 to 3, wherein the conductive shield is formed from a material having a specific resistance of at least 1 x 10-2 Ωm.

5. The electrically - actuated aerosol generator according to any one of claims 1 to 4, wherein the magnetic flux concentrator is formed from a single material or a plurality of materials having a relative permeability of at least 5 at a frequency of 6 - 8 MHz and a temperature of 25 degrees Celsius.

6. The electrically - actuated aerosol generator according to any one of claims 1 to 5, wherein the magnetic flux concentrator comprises a single ferromagnetic material or a plurality of ferromagnetic materials.

7. The electrically - actuated aerosol generator according to any one of claims 1 to 6, wherein the magnetic flux concentrator has a thickness of 0.3 mm to 5 mm.

8. The aerosol generator according to any one of claims 1 to 7, wherein the magnetic flux concentrator has a thickness that varies along its length, or around its perimeter, or in both along its length and around its perimeter.

9. The aerosol generator according to any one of claims 1 to 8, wherein the magnetic flux concentrator comprises a plurality of individual magnetic flux concentrator segments positioned adjacent to each other.

10. The electrically - actuated aerosol generator according to claim 9, wherein the plurality of magnetic flux concentrator segments includes a first magnetic flux concentrator segment formed from a first material and a second magnetic flux concentrator segment formed from a second, different material, and the first and second materials have different values of relative permeability.

11. The electrically - actuated aerosol generator according to claim 9 or 10, wherein the plurality of magnetic flux concentrator segments are tubular and are positioned coaxially along the length of the magnetic flux concentrator.

12. The electrically - actuated aerosol generator according to claim 9 or 10, wherein the plurality of magnetic flux concentrator segments are elongated and are positioned around the perimeter of the magnetic flux concentrator.

13. The electrically - actuated aerosol generator according to claim 12, wherein the plurality of elongated magnetic flux concentrator segments are arranged such that their longitudinal - axis directions are substantially parallel to the magnetic axis of the inductor coil.

14. The electrically actuated aerosol generator according to claim 12 or 13, further comprising an outer sleeve, wherein the inductor surrounds the inductor coil and has a plurality of longitudinal slots in which the elongated magnetic flux concentrator segments are held therein.

15. The electrically actuated aerosol generator according to claim 14, wherein the elongated magnetic flux concentrator segment is slidably held in the longitudinal slot such that the longitudinal position of the elongated magnetic flux concentrator segment relative to the inductor coil can be selectively varied.

16. An electrically actuated aerosol generation system comprising: an electrically actuated aerosol generator according to any one of claims 1 to 15; an aerosol generating article comprising an aerosol forming substrate; and a susceptor element positioned to heat the aerosol forming substrate during use, wherein the aerosol generating article is at least partially received in and disposed within the chamber such that the susceptor element can be inductively heated by the inductor of the aerosol generator, thereby heating the aerosol forming substrate of the aerosol generating article.

17. The electrically actuated aerosol generation system according to claim 16, wherein the aerosol forming substrate comprises a tobacco-containing material comprising a volatile tobacco flavor compound released from the aerosol forming substrate upon heating.

18. An inductor assembly for an electrically actuated aerosol generator, defining a chamber for receiving at least a portion of an aerosol generating article, an inductor coil disposed around at least a portion of the chamber, a magnetic flux concentrator disposed around the inductor coil and configured to distort a varying electromagnetic field generated by the inductor coil during use towards the chamber, a conductive shield disposed around the magnetic flux concentrator, and an inner sleeve having an outer surface on which the inductor coil is supported, the inner sleeve comprising protrusions on its outer surface at one or both ends of the inductor coil for holding the inductor coil on the inner sleeve.

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