Aerosol generating device with an inductor

Abstract

An electrically operated aerosol generating device (100) is provided 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) for receiving at least a portion of an aerosol-generating article, an inductor (200) having an inductor coil (210) arranged 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 current to the inductor coil so that, in use, the inductor coil generates a varying electromagnetic field to heat a susceptor element, thereby heating an aerosol-forming substrate.

Description

[Technical Field]

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

[0002] Several electrically operated aerosol generating systems have been proposed in the art, in which an aerosol generating device having an electric heater is used to heat an aerosol-forming substrate, such as a cigarette plug. One purpose 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. Typically, the aerosol-generating substrate is provided as part of an aerosol-generating article that is inserted into the chamber or cavity 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 capable of releasing volatile components capable of forming an aerosol. Other aerosol generating systems use induction heaters rather than resistance heating elements. An induction heater typically comprises an inductor that forms part of the aerosol generating device and a conductive susceptor element that is positioned in thermal proximity to the aerosol-forming substrate. The inductor generates a fluctuating electromagnetic field, generating eddy currents and hysteresis losses within the susceptor element, which causes the susceptor element to heat, thereby heating the aerosol-forming substrate. Induction heating allows aerosol generation without exposing the heater to the aerosol-generating article. This can improve the ease with which the heater can be cleaned. However, with induction heating, the inductor can also generate eddy currents and hysteresis losses in adjacent parts of the aerosol-generating device external to the inductor or in other conductive articles in close proximity to the aerosol-generating device. This can reduce the efficiency of the inductor and therefore the aerosol-generating device, and can also result in undesirable 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 chances of undesired heating of adjacent items. Summary of the Invention

[0004] According to a first aspect of the present invention, there is provided an electrically operated aerosol generating apparatus for heating an aerosol-generating article including an aerosol-forming substrate by heating a susceptor element positioned to heat the aerosol-forming substrate, the apparatus comprising: an apparatus housing defining a chamber for receiving at least a portion of the aerosol-generating article; an inductor having an inductor coil arranged around at least a portion of the chamber; and a power supply connected to the inductor coil and configured to provide high frequency current to the inductor coil so 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 magnetic flux concentrator comprising a plurality of individual magnetic flux concentrator segments.

[0005] Advantageously, by distorting the electromagnetic field toward the chamber, the magnetic flux concentrator may focus or concentrate the electromagnetic field within the chamber, which may increase the level of heat generated within the susceptor for a given level of power passing through the inductor coil compared to an inductor not provided with a magnetic flux concentrator, thus improving the efficiency of the aerosol generation device.

[0006] As used herein, the phrase "concentrating 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 toward the chamber, the magnetic flux concentrator may also reduce the extent to which the electromagnetic field propagates beyond the inductor. In other words, the magnetic flux concentrator may act as an electromagnetic shield. This may reduce undesired heating of adjacent conductive components of the device (e.g., if a metal outer housing is used) or adjacent conductive articles external to the device. By reducing undesired heating and losses from the inductor coil, the efficiency of the aerosol generating device may be further improved.

[0008] The term "aerosol-forming substrate", as used herein, relates to a substrate capable of releasing volatile compounds 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] The term "aerosol-generating article" as used herein 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.

[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 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 article and device cooperate to generate a respirable aerosol.

[0012] As used herein, the term "magnetic flux concentrator" refers to a component with high relative magnetic permeability that functions to concentrate and guide the electromagnetic field or lines of 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", where μ is 4π×10 -7 NA -2 is.

[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 ​​for frequencies between 6 and 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 between 500 kHz and 10 MHz.

[0016] Preferably, the magnetic flux concentrator comprises a material or combination of materials having a relative permeability of at least 5 at 25 degrees Celsius, and preferably at least 20 at 25 degrees Celsius. The magnetic flux concentrator may be formed from a number 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, and preferably at least 20 at 25 degrees Celsius. These exemplary values ​​preferably refer to relative permeability values ​​for frequencies between 6 and 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. Preferably, the magnetic flux concentrator comprises a ferromagnetic material (e.g., a ferrite material, a ferrite powder held in a binder, etc.) or any other suitable material, including a ferrite material such as ferritic iron, ferromagnetic steel, or stainless steel.

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

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

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

[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 a central portion of the magnetic flux concentrator from one end to the other or toward 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 to 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 periphery. In other examples, the thickness of the magnetic flux concentrator may vary around its periphery.

[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 along substantially 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 partially around the circumference of the inductor coil. Preferably, the magnetic flux concentrator is 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. If 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. Preferably, the magnetic flux concentrator 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 annulus.

[0025] The magnetic flux concentrator comprises a plurality of individual magnetic flux concentrator segments positioned adjacent to one another. Thus, the magnetic flux concentrator is an assembly of a plurality of individual components. This allows tuning the magnetic flux concentrator, and therefore the degree to which the electromagnetic field is distorted, by removing 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 magnetic permeability, such as plastic, to reduce the degree to which the electromagnetic field is distorted by the magnetic flux concentrator. This "tuning" of the magnetic flux concentrator may allow a predetermined value of electromagnetic field strength to be achieved within the chamber, for example, at the position where the susceptor element will be located during use.

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

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

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

[0029] Where the magnetic flux concentrator comprises multiple individual magnetic flux concentrator segments positioned adjacent to one another, the individual magnetic flux concentrator segments may be formed from the same material or combination of materials as one another. In such an embodiment, the magnetic flux concentrator may be tailored by using magnetic 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, the first and second materials having different values ​​of relative permeability. This allows the magnetic flux concentrator to be adjusted during assembly to achieve a desired level of induction from the inductor coil and a desired level of electromagnetic flux within the chamber without necessarily changing the dimensions of the magnetic flux concentrator. Each of the magnetic flux concentrator segments can be made from different materials, from the same material, or any combination thereof.

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

[0032] In certain embodiments, the multiple magnetic flux concentrator segments are tubular and 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 coil's length. The tubular magnetic flux concentrator segments may be cylindrical. In other embodiments, the thickness of one or more of the tubular segments may vary along its length. When the magnetic flux concentrator segments are tubular, they may have any suitable cross-section. For example, the tubular magnetic flux concentrator segments may have a square, oval, rectangular, triangular, pentagonal, hexagonal, or similar cross-sectional shape depending on the desired shape of the resulting magnetic flux concentrator. Preferably, each tubular magnetic flux concentrator segment has a circular cross-sectional shape. For example, the tubular magnetic flux concentrator segments may have an annular cylindrical shape. In other words, each tubular magnetic flux concentrator segment may form a cylindrical annulus.

[0033] In certain other embodiments, the multiple magnetic flux concentrator segments are elongated and positioned around the periphery of the magnetic flux concentrator. As used herein, the term "elongated" refers to a component having a length 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, oval, rectangular, triangular, pentagonal, hexagonal, or similar cross-sectional shape depending on 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 arc-shaped 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 external shape of the inductor coil, reducing the overall dimensions of the inductor and the device itself.

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

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

[0036] The magnetic flux concentrator segments can be attached directly to the inductor coil, for example, using an adhesive. The inductor can further include one or more intermediate components between the inductor coil and the magnetic flux concentrator segments, which hold the segments in place relative to the inductor coil. For example, the inductor can further include an outer sleeve surrounding the inductor coil to which the segments are attached. The outer sleeve can have several slots or recesses in which the segments are held. If the magnetic flux concentrator segments are annular, the recesses can be annular and positioned to hold the annular segments.

[0037] When the multiple 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 multiple longitudinal slots within which the elongated magnetic flux concentrator segments are held.

[0038] The elongated magnetic flux concentrator segments may be fixed in place relative to the outer sleeve, for example, the segments may be attached to the outer sleeve using an adhesive.

[0039] The elongated magnetic flux concentrator segments are preferably slidably retained in the longitudinal slots so that the longitudinal position of the elongated magnetic flux concentrator segments relative to the inductor coil can be selectively varied. This may allow for further adjustment of the magnetic flux concentrator to achieve a desired electromagnetic field within the chamber. The elongated magnetic flux concentrator segments may be slidably retained in the longitudinal slots by one or more non-adhesive retention means associated with each longitudinal slot and positioned to engage an outer surface of the elongated segment received in the slot and prevent radial removal of the segment from the slot. For example, the outer sleeve may include one or more non-adhesive retention means for each longitudinal slot in the form of retention tabs or clips extending partially across the width of the slot, or retention strips extending the entire width of the slot, which retain the radial position of the segment relative to the outer sleeve while allowing longitudinal movement of the segment relative to the outer sleeve.

[0040] Preferably, the longitudinal slots have a length greater than the length of the elongated segments. This configuration allows the segments to be supported by the slots even when their longitudinal positions relative to the outer sleeve are changed. In other examples, the slots may be open-ended, so that the segments can extend partially beyond the slots when their longitudinal positions are changed.

[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 a segment may taper or decrease from a central portion of the segment from one end to the other or toward both ends. In a preferred embodiment, the elongated magnetic flux concentrator segments are wedge-shaped, meaning 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 disposed on the outer sleeve such that they are separated from one another 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 into the housing of the device, for example, the inductor coil and 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 can define a sidewall of the chamber along at least a portion of the length of the chamber. The inner sleeve can be made of any suitable material, such as plastic. The inner sleeve can form part of the device housing. The inner sleeve can be a separate component connected to the device housing. The inner sleeve can be removable from the device housing, for example, to allow for repair or replacement of the inductor assembly.

[0045] The inner sleeve preferably includes at least one protrusion on its outer surface at one or both ends of the inductor coil for retaining the inductor coil on the inner sleeve. The at least one protrusion prevents or reduces longitudinal movement of the inductor coil relative to the inner sleeve. Preferably, the at least one protrusion is provided on the inner sleeve at both ends of the inductor coil. The at least one protrusion may, for example, include multiple protrusions at either end of the inductor coil arranged in a pattern. The multiple protrusions may include a single protrusion at either end of the inductor coil. The at least one protrusion may include a protrusion extending around the entire circumference of the inner sleeve at either end of the inductor coil.

[0046] At least one protrusion extends radially from the outer surface. Preferably, the at least one protrusion extends above the outer surface a distance greater than the thickness of the inductor coil. In this manner, the at least one protrusion extends above the inductor coil, thereby preventing longitudinal movement of the inductor coil beyond the at least one protrusion. If the inductor further includes an outer sleeve to which the plurality of magnetic flux concentrator segments are connected, the at least one protrusion is preferably positioned to hold the outer sleeve in place. For example, the at least one protrusion preferably extends above the outer surface a distance greater than the combined thickness of the inductor coil and outer sleeve. In this manner, the at least one protrusion may abut either or both ends of both the outer sleeve and the inductor coil to prevent any longitudinal movement relative to the inner sleeve.

[0047] The aerosol generating device is preferably portable. The aerosol generating device may be comparable in size to 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. 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 device. For example, the power source may have a capacity sufficient to allow for continuous production of aerosol for approximately six minutes, or a multiple of six minutes, corresponding to the typical time it takes to smoke a conventional cigarette. In another example, the power source may have a capacity sufficient to allow for a predetermined number of puffs or for discontinuous activation.

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

[0050] The apparatus may include one or more susceptor elements within the chamber, which are arranged to heat the aerosol-forming substrate of an aerosol-generating article received in the chamber. For example, the apparatus may include one or more susceptor elements formed in the same manner as described below in connection with the aerosol-generating article. The apparatus may include one or more external susceptor elements that remain outside 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 the inductor coil. For example, the one or more external susceptor elements may extend at least partially around the aerosol-generating article. The apparatus may include one or more internal susceptor elements that extend at least partially 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 the inductor coil. For example, the 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. The one or more susceptor elements may include susceptor blades within the chamber. The apparatus may include one or more external susceptor elements and one or more internal susceptor elements as described above.

[0051] When the apparatus includes one or more susceptor elements within the chamber, the one or more susceptor elements may be attached to the apparatus. One or more susceptor elements may be removable from the apparatus. This may allow one or more susceptor elements to be replaced independently of the apparatus. For example, one or more susceptor elements may be removable as one or more individual components or as part of a removable inductor assembly. The apparatus may include multiple susceptor elements within the chamber. The multiple susceptor elements within the chamber may be fixed within the chamber. One or more of the multiple susceptor elements may be removable from the apparatus so that they can be replaced. The multiple 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 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 lightweight and not brittle.

[0053] The device 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 delivery to the user and may reduce the concentration of the aerosol before delivery to the user. As used herein, the term "mouthpiece" refers to the portion of the aerosol-generating device that is placed in the mouth of a user to directly inhale the aerosol generated by the aerosol-generating device from an aerosol-generating article received in the chamber of the housing.

[0054] The aerosol-generating device may include a user interface for activating the device, such as a button to initiate heating of the device, or a display that indicates the status of the device or the aerosol-forming substrate.

[0055] According to a second aspect of the present invention, there is provided an electrically operated aerosol generation system comprising an electrically operated aerosol generating device according to any of the embodiments described above, 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.

[0056] Preferably, the aerosol-forming substrate comprises a tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating. However, the aerosol-forming substrate may also comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former that promotes the formation of a dense, 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 upon use. Preferably, a suitable aerosol former is 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 assemblage 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 include 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. In use, changing the electromagnetic field generated by the inductor coil heats the susceptor element, which then transfers heat to the aerosol-forming substrate of the aerosol-forming article primarily 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 shape, type, distribution, and arrangement of the susceptor may be selected according to the needs of the user.

[0060] A susceptor element may 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 may be described as an elongated susceptor element. The susceptor element is disposed substantially longitudinally within the rod. This means that the length dimension of the elongated susceptor element is disposed approximately parallel to the longitudinal axis of the rod, for example, within ±10 degrees of 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 extend along the longitudinal axis of the rod.

[0061] The susceptor elements are preferably in the form of pins, rods, blades, or plates. The susceptor elements are preferably 5 mm to 15 mm in length, e.g., 6 mm to 12 mm, or 8 mm to 10 mm. The susceptor elements are preferably 1 mm to 5 mm in width and 0.01 mm to 2 mm in thickness, e.g., 0.5 mm to 2 mm. Preferred embodiments may have a thickness of 10 micrometers to 500 micrometers, with 10 to 100 micrometers being even more preferred. When the susceptor elements have a constant cross-section, e.g., a circular cross-section, the preferred width or diameter may 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 include metal or carbon. Preferred susceptor elements can include ferromagnetic materials, such as ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements can be or include aluminum. Preferred susceptor elements can be formed from 400 series stainless steel, such as grade 410, grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in an electromagnetic field having similar values ​​of frequency and field strength. Thus, any of the susceptor element parameters, such as material type, length, width, and thickness, can be varied to provide a desired power distribution within a known electromagnetic field.

[0063] Preferred susceptor elements are capable of being heated to temperatures in excess of 250 degrees Celsius. Suitable susceptor elements may comprise a non-metallic core having disposed thereon a metallic layer, for example a metallic band formed on the surface of the ceramic core.

[0064] The susceptor element may have a protective outer layer, such as a protective ceramic or glass layer, that encapsulates the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor material.

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

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

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

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

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

[0070] The aerosol-forming substrate may 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 may have a length of approximately 10 mm. Alternatively, the aerosol-forming segment may have a length of approximately 12 mm.

[0071] 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 about 5 mm to about 12 mm. In one embodiment, the aerosol-forming segment may have an outer diameter of about 7.2 mm.

[0072] 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. In one embodiment, the length of the filter plug is approximately 7 mm, but may be between approximately 5 mm and approximately 10 mm.

[0073] The aerosol-generating article may comprise an outer paper wrapper. Additionally, the aerosol-generating article may comprise a separation between the aerosol-forming substrate and the filter plug. The separation may be approximately 18 mm, but may also range from 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, although the aerosol generating system may also include additional components, such as a charging unit for recharging an on-board power supply in an electrically operated or 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 that is removable from the rest 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, comprising: an inductor coil defining a chamber for receiving at least a portion of an aerosol-generating article and arranged around at least a portion of the chamber; and a magnetic flux concentrator arranged around the inductor coil and configured to distort a varying electromagnetic field generated by the inductor coil toward the chamber during use, wherein the magnetic flux concentrator comprises a plurality of individual magnetic flux concentrator segments positioned adjacent to one another.

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

[0078] According to a fourth aspect of the present invention, there is provided an electrically operated aerosol generating apparatus for heating an aerosol-generating article including an aerosol-forming substrate by heating a susceptor element positioned so as to heat the aerosol-forming substrate, the apparatus comprising: an apparatus housing defining a chamber for receiving at least a portion of the aerosol-generating article; an inductor having an inductor coil arranged 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 so 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 positioned around the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil towards the chamber during use; and the inductor further comprises a buffer element positioned between the magnetic flux concentrator and the apparatus housing.

[0079] As used herein, the term "cushioning element" refers to a resilient component configured to deform during a collision to absorb kinetic energy, thereby reducing the severity of the shock transmitted by the device housing to the magnetic flux concentrator during the collision.

[0080] With this configuration, the buffer element reduces the risk of damage to the magnetic flux concentrator during manufacturing, transportation, handling, and use. Furthermore, it may also allow the thickness of the magnetic flux concentrator to be reduced. Reducing the thickness of the magnetic flux concentrator may allow the overall size and weight of the aerosol generating device to be reduced, and may allow such devices to be manufactured more cost-effectively and using less raw materials.

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

[0082] In certain embodiments, the cushioning 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 of the circumference of the magnetic flux concentrator, preferably at least 95 percent, and more preferably at least 97 percent of the circumference of the magnetic flux concentrator. In such embodiments, the cushioning element may comprise one or more resilient O-rings extending around the circumference of the magnetic flux concentrator.

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

[0084] With this configuration, relative movement between the magnetic flux concentrator and the buffering element can be avoided to ensure proper performance of the buffering element. Furthermore, by bonding the buffering element to the magnetic flux concentrator, the performance of the magnetic flux concentrator can be maintained even if the magnetic flux concentrator accidentally breaks off during a collision because the broken pieces of the magnetic flux concentrator are held by the buffering element in substantially the same position as before the breakage.

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

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

[0087] The cushioning element may be formed from any suitable elastic material or materials.

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

[0089] According to a fifth aspect of the present invention, there is provided an electrically operated aerosol generation system comprising an electrically operated aerosol generating apparatus according to any embodiment described above in relation 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 apparatus, thereby heating the aerosol-forming substrate of an aerosol-generating article received in the chamber.

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

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

[0092] In certain embodiments, the cushioning element extends substantially around the entire periphery of the magnetic flux concentrator. In such embodiments, the cushioning element may comprise one or more resilient O-rings extending around the periphery of the magnetic flux concentrator. In preferred embodiments, the cushioning element is adhered to substantially the entire outer surface of the magnetic flux concentrator. In particularly preferred embodiments, the magnetic flux concentrator is encased within the cushioning element.

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

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

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

[0096] With this configuration, the shielding acts to reduce distortion of the electromagnetic field by conductive or highly magnetically susceptible materials in the immediate vicinity of the device or in the housing of the device itself. This may allow the electromagnetic field generated by the inductor coil to be more consistent. Furthermore, it may allow the inductor to be calibrated for a certain desired level of performance without having to consider the material from which the device's outer housing is made. For example, the metal shielding may allow an inductor of the same configuration to produce substantially the same results whether used in a device with a plastic housing or a device with a metal housing. In other words, providing a conductive shield means that the effect of the device housing on the electromagnetic field generated by the inductor coil is negligible.

[0097] The shield may include or be formed from any suitable conductive material. For example, the shield may be formed from a conductive polymer. The conductive shield may be a metallic shield. For example, the conductive shield may be a metal foil that extends around the magnetic flux concentrator. The shield may be a conductive coating applied to a component that extends around the magnetic flux concentrator. For example, the shield may be a metal coating applied to a surface of a non-metallic sleeve that extends around the magnetic flux concentrator. The metal coating may be applied in any suitable manner, such as, for example, with a metallic paint, a metallic ink, or by 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 magnetic 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 must be at least 1x10 -2 Ωm, preferably at least 1x10 -4 Ωm, more preferably at least 1x10 -6 It is preferably made of a material having a resistivity of Ωm.

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

[0101] According to an eighth aspect of the present invention, there is provided an electrically operated aerosol generation system comprising an electrically operated aerosol generating apparatus according to any embodiment described above in relation 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 apparatus, thereby heating the aerosol-forming substrate of an aerosol-generating article received in the chamber.

[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 comprising: an inductor coil defining a chamber for receiving at least a portion of an aerosol-generating article and 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 in use towards the chamber; and a conductive shield disposed around the magnetic flux concentrator, the shield being configured to redirect the electromagnetic field away from a region outside 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.

[0104] Features described with respect to one or more aspects may be equally applicable to the other aspects of the invention. In particular, features described with respect to the apparatus of the first aspect may equally be applied to the apparatus 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. [Brief explanation of the drawings]

[0105] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0106] [Figure 1] FIG. 1 is a schematic longitudinal cross-sectional view of an electrically actuated aerosol generating system according to the present invention. [Figure 2] 2 is a longitudinal cross-sectional view of a first embodiment of an inductor for the aerosol generation system of FIG. 1. FIG. [Figure 3] FIG. 3 is a perspective view of the inductor of FIG. [Figure 4] Figure 4A is a longitudinal cross-sectional view of the inductor of Figure 2, showing an exemplary electromagnetic field generated in the top half of the inductor and with the inner sleeve omitted for clarity. Figure 4B is a longitudinal cross-sectional view of a prior art inductor, showing an exemplary electromagnetic field generated in the top half of the inductor. [Figure 5] FIG. 5 is a longitudinal cross-sectional view of a second embodiment of an inductor for the aerosol generation system of FIG. [Figure 6] FIG. 6 is a perspective view of the inductor of FIG. [Figure 7] FIG. 7 is a longitudinal cross-sectional view of a third embodiment of an inductor for the aerosol generation system of FIG. [Figure 8] FIG. 8 is a perspective view of the inductor of FIG. [Figure 9] FIG. 9 is a cross-sectional view of the inductor taken along line 9-9 of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0107] FIG. 1 shows a schematic cross-sectional view of an electrically operated aerosol generating device 100 and an aerosol-generating article 10, which together form an electrically operated aerosol generation system. The electrically operated aerosol generating device 100 includes a device housing 110 defining a chamber 120 for receiving the aerosol-generating article 10. The proximal end of the housing 110 has an insertion opening 130 through which the aerosol-generating article 10 can be inserted into and removed from the chamber 120. An inductor 200 is disposed within the device 100 between the outer wall of the housing 110 and the chamber 120. The inductor 200 includes a helical inductor coil having a magnetic axis that corresponds to the longitudinal axis of the chamber 120, which in this embodiment also corresponds to the longitudinal axis of the device 100. As shown in FIG. 1 , the inductor 200 is positioned adjacent to a distal portion of the chamber 120 and, in this embodiment, extends along a portion of the length of the chamber 120. In other embodiments, inductor 200 may extend along the entire or substantially the entire length of chamber 120, or may extend along a portion of the length of chamber 120, for example, positioned adjacent a proximal portion of chamber 120 and away from a distal portion of chamber 120. Inductor 200 is further described below in connection with FIG. 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 having circuitry, etc.), both located in a distal region of the housing 110. Both the electronic device 150 and the inductor 200 receive power from the power source 140 via electrical connections (not shown) extending through the housing 110. The chamber 120 is preferably separated from the inductor 200 and the distal region of the housing 110 containing the power source 140 and the electronic device 150 by a liquid-tight separator. Thus, the electrical components within the device 100 can remain isolated from aerosols or residues generated within the chamber 120 by the aerosol-generating process. This can also facilitate cleaning of the device 100, as the chamber 120 can be completely empty when no aerosol-generating article is present. Furthermore, because potentially fragile elements are not exposed within the chamber 120, the risk of damage to the device, either during insertion of an aerosol-generating article or during cleaning, can be reduced. Ventilation holes (not shown) may be provided in the walls of the housing 110 to allow airflow into the chamber 120 .

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

[0110] When the device 100 is activated, a high-frequency alternating current passes through the inductor coil of the inductor 200, causing the inductor 200 to generate a varying electromagnetic field within the distal portion of the chamber 120 of the device 100. The frequency of the electromagnetic field varies between 1 and 30 MHz, preferably between 2 and 10 MHz, e.g., between 5 and 7 MHz. When the aerosol-generating article 10 is properly positioned within the chamber 120, the susceptor 30 of the article 10 is positioned within this varying electromagnetic field. The varying electromagnetic field generates eddy currents within the susceptor 30, which then heats up. Further heating is provided by magnetic hysteresis losses within the 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 a user. Such actuation can be manual or can occur automatically in response to a user inhaling the aerosol-generating article 10.

[0111] 2 and 3, inductor 200 is tubular and comprises a helically wound, cylindrical inductor coil 210 surrounding a tubular inner sleeve 220. Both inductor coil 210 and inner sleeve 220 are surrounded by a tubular magnetic flux concentrator 230 that extends along the length of inductor coil 210. Inductor 200 may further include a cushioning element (not shown) within which magnetic flux concentrator 230 is encased to provide shock resistance to the magnetic flux concentrator. The cushioning element is in the form of a silicone rubber sleeve within which the magnetic flux concentrator is held. Inductor 200 may further include a conductive shield (not shown) disposed around magnetic flux concentrator 230 and further encased within the cushioning element. The shield is configured to redirect the electromagnetic field away from the area outside inductor 200. The conductive shield is provided as a metallic coating deposited on 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 wire 212 and has multiple turns or turns extending along its length. The wire 212 may have any suitable cross-sectional shape, such as square, oval, or triangular. In this embodiment, the wire 212 has a circular cross-sectional shape. In other embodiments, the wire may have a flat cross-sectional shape. For example, the inductor coil may be formed from wire having a rectangular cross-sectional shape and wound such that the maximum width of the wire's cross section extends parallel to the magnetic axis of the inductor coil. Such a flat inductor coil may allow the outer diameter of the inductor, and therefore the outer diameter of the device, to be minimized.

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

[0114] The magnetic flux concentrator 230 is mounted around the inductor coil 210 and is held in place by a protrusion 226 on the outer surface 222 of the sleeve 220. The magnetic flux concentrator 230 is formed from a material having a high relative magnetic permeability, so that the electromagnetic field generated by the inductor coil 210 is attracted to and guided by the magnetic flux concentrator 230. This is illustrated 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, so 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 acts as a magnetic shield. This may reduce undesired heating of or interference with external objects compared to the prior art inductor 400. The electromagnetic field lines within the interior 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 may increase the current generated in a susceptor placed within the chamber. In this manner, the electromagnetic field is concentrated toward the chamber, thereby allowing for more efficient heating of the susceptor.

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

[0116] The magnetic flux concentrator is preferably made from a single material or materials having a high relative magnetic permeability, i.e., a material having a relative magnetic 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) when measured at 25°C. These exemplary values ​​may refer to the relative magnetic permeability of the magnetic flux concentrator material for frequencies between 6 and 8 MHz and a temperature of 25°C. In this embodiment, the magnetic flux concentrator is a single component. In other embodiments, the magnetic flux concentrator may be formed from a layer of sheet material or from multiple individual segments, as described below in connection with Figures 5-9. In this example, the thickness of the magnetic flux concentrator is substantially constant along its length and is selected based on the materials used for the magnetic flux concentrator and the amount of electromagnetic field distortion required. For example, if the magnetic flux concentrator is made from ferrite, its thickness may range from 0.3 mm to 5 mm, preferably from 0.5 mm to 1.5 mm.

[0117] FIGS. 5 and 6 illustrate a second embodiment of inductor 500. Second embodiment inductor 500 is similar in structure and operation to the first embodiment of inductor 200 shown in FIGS. 1-4A, and like reference numerals are used where identical features are present. However, unlike first embodiment inductor 200, second embodiment inductor 500 includes a magnetic flux concentrator 530 that is not a single component. Instead, the magnetic flux concentrator segments 531, 532, 533, 534, and 535 are formed adjacent to one another. Magnetic flux concentrator segments 531, 532, 533, 534, and 535 are tubular and positioned coaxially along the length of magnetic flux concentrator 530. In this example, the magnetic flux concentrator segments have an annular cylindrical shape. As a result, magnetic flux concentrator 530 also has an annular cylindrical shape. However, it should be understood that 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 one another such that they abut in a 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 magnetic flux concentrator segments to form the magnetic flux concentrator 530 allows the magnetic flux concentrator to be assembled using different segments having different relative magnetic permeability values. For example, a magnetic flux concentrator can be formed from one or more magnetic flux concentrator segments made from a first material having a first relative magnetic permeability and one or more magnetic flux concentrator segments made from a second material having a second relative magnetic permeability. This allows the magnetic flux concentrator to be "fine-tuned" during assembly to achieve a desired level of induction from the inductor coil and a desired level of electromagnetic flux within a chamber in which the susceptor of the aerosol-generating article is located during use. Each of the magnetic flux concentrator segments can be made from different materials, from the same material, or any combination thereof.

[0119] Similar to the first embodiment inductor 200, 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 magnetic flux concentrator 530 are held in place.

[0120] Additionally, similar to the first embodiment inductor 200, inductor 500 may further include a cushioning element (not shown) within which individual segments of magnetic flux concentrator 530 are encased, thereby providing shock resistance to the magnetic flux concentrator, and may further include a conductive shield disposed around magnetic flux concentrator 530 and configured to redirect the electromagnetic field away from areas outside inductor 500. As magnetic flux concentrator 530 is provided as a plurality of individual segments, so too are the conductive shield and cushioning element. This allows the magnetic flux concentrator to be finely tuned by replacing magnetic flux concentrator segments with their corresponding conductive shield segments and cushioning element segments.

[0121] FIGS. 7-9 illustrate an inductor 700 according to a third embodiment. The third embodiment inductor 700 is similar in structure and operation to the first and second inductor embodiments shown in FIGS. 1-6, and like reference numerals are used where identical features are present. Like the second embodiment inductor 500, the magnetic flux concentrator 730 is not a single component but instead is formed from multiple magnetic flux concentrator segments 731, 732, 733, 734, and 735 positioned adjacent to one another. Unlike the second embodiment magnetic flux concentrator 530, the magnetic flux concentrator segments 731, 732, 733, 734, and 735 are elongated and 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 this end, outer sleeve 736 includes a plurality of longitudinal slots 737 in which the magnetic flux concentrator segments are slidably retained. In this embodiment, outer sleeve 736 has an annular cylindrical shape, and the magnetic flux concentrator segments have arcuate cross sections corresponding to the outer shape of the outer sleeve. As a result, magnetic flux concentrator 730 also has an annular cylindrical shape. However, it should be appreciated that 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, the magnetic flux concentrator segments each slide within their respective slots 737, thereby changing their respective longitudinal positions while remaining within their respective slots. This allows 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 may increase along its length from one of its ends to the other, allowing for further tailoring 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 the desired level of induction.

[0122] In this example, the elongated magnetic flux concentrator segments are disposed on 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 may be in direct contact with one or both of the magnetic flux concentrator segments on either 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 either side 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] Additionally, similar to inductor 200 of the first and second embodiments, inductor 700 may further include a cushioning element (not shown) within which individual segments of magnetic flux concentrator 570 are encased, thereby providing shock resistance to the magnetic flux concentrator, and may further include a conductive shield disposed around magnetic flux concentrator 730 and configured to redirect the electromagnetic field away from areas outside inductor 700. As magnetic flux concentrator 730 is provided as a plurality of individual segments, so too are the conductive shield and cushioning element. This allows the magnetic flux concentrator to be finely tuned by replacing magnetic flux concentrator segments 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 magnetic permeability values. For example, the magnetic flux concentrator may be formed from one or more elongated magnetic flux concentrator segments made from a first material having a first relative magnetic permeability and one or more elongated magnetic flux concentrator segments made from a second material having a second relative magnetic permeability. This allows the magnetic flux concentrator to be "fine-tuned" during assembly to achieve a desired level of induction from the inductor coil and a desired level of electromagnetic flux within a chamber in which the susceptor of the aerosol-generating article is located during use. To this end, each of the elongated magnetic flux concentrator segments may be made from different materials, from the same material, or any combination thereof.

[0126] The above exemplary embodiments are not intended to limit the scope of the claims, and other embodiments consistent with the above exemplary embodiments will be apparent to those skilled in the art.

[0127] For example, in the embodiments described above, the inductor includes an inner sleeve that forms the sidewall of the chamber and 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 along with the rest of the inductor. In other embodiments, the inductor coil and magnetic flux concentrator may be incorporated into the housing of the device, for example, molded into the material from which the housing is formed. In such embodiments, an inner sleeve is not required.

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

[0129] Additionally, the magnetic flux concentrator has been described as a single component or as being formed from multiple tubular or elongated magnetic flux concentrator segments. However, it will be appreciated 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 and tubular magnetic flux concentrator segments.

Claims

1. 1. An electrically operated aerosol generating apparatus for heating an aerosol-generating article including an aerosol-forming substrate by heating a susceptor element positioned to heat the aerosol-forming substrate, comprising: 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 the aerosol-forming substrate; the inductor further comprising a magnetic flux concentrator disposed about the inductor coil and configured to distort the varying electromagnetic field generated by the inductor coil toward the chamber during use, the magnetic flux concentrator comprising a plurality of individual magnetic flux concentrator segments positioned adjacent to one another; the plurality of magnetic flux concentrator segments are tubular and positioned coaxially along the length of the inductor coil; or the plurality of magnetic flux concentrator segments are elongated and positioned around the inductor coil; An electrically operated aerosol generator.

2. 10. The electrically operated aerosol generating device of claim 1, wherein the magnetic flux concentrator is formed from a single material or multiple materials having a relative magnetic permeability of at least 5 at a frequency of 6-8 MHz and a temperature of 25 degrees Celsius.

3. 3. The electrically operated aerosol generating device of claim 1, wherein the magnetic flux concentrator comprises a single ferromagnetic material or multiple ferromagnetic materials.

4. 4. An electrically operated aerosol generating device according to claim 1, wherein the magnetic flux concentrator has a thickness of between 0.3 mm and 5 mm.

5. 5. An aerosol generating device according to any preceding claim, wherein the magnetic flux concentrator has a thickness that varies along its length, or varies around its circumference, or varies both along its length and around its circumference.

6. 6. An electrically operated aerosol generating device as described in any one of claims 1 to 5, 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, the first and second materials having different values ​​of relative magnetic permeability.

7. An electrically operated aerosol generating device as described in any of claims 1 to 6, wherein the plurality of magnetic flux concentrator segments are elongated and positioned around the inductor coil, and the plurality of elongated magnetic flux concentrator segments are arranged so that their longitudinal axes are substantially parallel to the magnetic axis of the inductor coil.

8. 8. An electrically operated aerosol generating device according to claim 1, wherein the inductor further comprises an inner sleeve having an outer surface on which the inductor coil is supported.

9. 9. The electrically operated aerosol generating device of claim 8, wherein the inner sleeve comprises protrusions on its outer surface at one or both ends of the inductor coil for retaining the inductor coil on the inner sleeve.

10. 10. An electrically operated aerosol generation system comprising: an electrically operated aerosol generating device according to any one of claims 1 to 9; 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 the chamber such that the susceptor element is inductively heatable by the inductor of the aerosol generating device, thereby heating the aerosol-forming substrate of the aerosol-generating article.

11. 11. The electrically operated aerosol generating system of claim 10, wherein the aerosol-forming substrate comprises a tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating.

12. 1. 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; a magnetic flux concentrator disposed around the inductor coil and configured to distort a varying electromagnetic field generated by the inductor coil toward the chamber during use, the magnetic flux concentrator comprising a plurality of individual magnetic flux concentrator segments positioned adjacent to one another; the plurality of individual magnetic flux concentrator segments are tubular and positioned coaxially along the length of the inductor coil; or the plurality of individual magnetic flux concentrator segments are elongated and positioned around the inductor coil; Inductor assembly.

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