A susceptor assembly comprising one or more composite susceptor particles

Abstract

This invention relates to a receptor assembly comprising one or more composite receptor particles for inductively heating an aerosol forming matrix under the influence of an alternating magnetic field. Each of the one or more receptor particles comprises a particle core and a particle shell that completely encapsulates the particle core. The particle core comprises, or is made of, a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a temperature of 20 degrees Celsius for frequencies up to 10 kHz. The particle shell comprises or is made of a conductive shell material. This disclosure further relates to aerosol generating articles comprising such receptor assemblies, and to aerosol generating systems comprising such articles and aerosol generating apparatus. Additionally, this disclosure relates to a method of manufacturing such receptor assemblies.

Description

Technical Field

[0001] This invention relates to a receptor assembly comprising one or more composite receptor particles for inductively heating an aerosol-forming matrix under the influence of an alternating magnetic field. This disclosure further relates to aerosol-generating articles comprising such receptor assemblies, and to aerosol-generating systems comprising such articles and aerosol-generating apparatus. Additionally, this disclosure relates to a method of manufacturing such receptor assemblies. Background Technology

[0002] Generating inhalable aerosols by inductively heating an aerosol-forming matrix is ​​generally known in the prior art. For this purpose, the matrix can be arranged in thermal proximity or direct physical contact with a receptor capable of generating heat due to at least one of eddy currents or hysteresis losses when exposed to an alternating magnetic field. For example, the receptor may comprise one or more receptor particles embedded in the aerosol-forming matrix. The matrix and receptor together may be part of an aerosol-generating article configured to be inserted into an aerosol-generating apparatus including an induction source for generating the alternating magnetic field.

[0003] To control the temperature of the substrate, a sensor assembly has been proposed, comprising a first sensor and a second sensor made of different materials. The first sensor material can be optimized in terms of heat loss and therefore heating efficiency. In contrast, the second sensor material can be used as a temperature marker. For this purpose, the second sensor material is selected to have a Curie temperature corresponding to a predetermined operating temperature of the sensor assembly. At its Curie temperature, the magnetic properties of the second sensor change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a temporary change in its resistance. Therefore, by monitoring the corresponding change in the current absorbed by the sensing source, it is possible to detect when the second sensor material reaches its Curie temperature, and thus when it reaches the predetermined operating temperature. To avoid rapid overheating, the heating process must be controlled by actively reducing or shutting off the heating power when the operating temperature is reached. Summary of the Invention

[0004] It is desirable to have sensor components, aerosol generating articles, and aerosol generating systems that possess the advantages of existing technological solutions while mitigating their limitations. In particular, it is desirable to have sensor components, aerosol generating articles, and aerosol generating apparatus systems that offer improved heating efficiency and enhanced temperature control capabilities.

[0005] According to one aspect of the invention, a receptor assembly is provided for inductively heating an aerosol-forming matrix under the influence of an alternating magnetic field. The receptor assembly includes one or more composite receptor particles. Each of the one or more receptor particles includes a particle core and a particle shell that completely encapsulates the particle core. The particle core comprises, or is made of, a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a frequency of 10 kHz (kilohertz), particularly for frequencies up to 10 kHz (kilohertz), and at a temperature of 20 degrees Celsius. That is, the particle core comprises, or is made of, a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a temperature of 20 degrees Celsius when penetrated by an alternating magnetic field with a frequency of 10 kHz (kilohertz), particularly for frequencies up to 10 kHz (kilohertz). The particle shell comprises or is made of a conductive shell material.

[0006] According to the present invention, it has been found that sensor particles comprising a magnetic core with high permeability and a conductive shell provide both improved heating efficiency and improved temperature control with self-regulating characteristics. In this regard, the magnetic core with high permeability has been found to act as a flux concentrator that increases the magnetic flux through the particle shell. According to Faraday's law of induction, the increase in magnetic flux leads to an increase in the electromotive force around the closed path through the conductive shell material, which in turn increases the eddy current losses in the particle shell. Therefore, the high permeability of the magnetic core increases the heat generated in the particle shell during use. Advantageously, this also allows for a thinner particle shell, and thus saves on the materials and costs used in manufacturing the sensor particles.

[0007] Furthermore, it has been found that the magnetic core can be used to control the amount of heat generated in the particle shell, which varies with the actual temperature of the sensor assembly. This is because, at the Curie temperature of the core material, the magnetic properties of the particle core change from ferromagnetic or ferrimagnetic to paramagnetic. As a result, when the sensor assembly reaches the Curie temperature of the core material, the overall effective permeability of the composite sensor particles decreases to a uniform level. With the disappearance of hysteresis in the core material, heat generation in the particle core due to hysteresis losses ceases. More importantly, the change in permeability also affects heat generation in the particle shell, as the decrease in permeability reduces the magnetic flux through the conductive shell. This, in turn, leads to a decrease in electromotive force when the sensor assembly reaches the Curie temperature of the core material, and thus a reduction in eddy current losses of heat generation in the particle shell. In addition, the skin depth of the particle shell (a measure of the degree of conductivity occurring in the conductive shell material when exposed to an alternating magnetic field) depends on the overall effective permeability of the composite sensor particles. Therefore, the decrease in the overall effective permeability of the sensor particles caused by the decrease in permeability in the particle core leads to an increase in the skin depth in the shell. This, in turn, reduces the effective resistance of the conductive particle shell. Consequently, when the Curie temperature of the core material is reached, the reduced effective resistance also reduces eddy current losses in the shell material, thus reducing heat generation in the particle shell. Therefore, at the Curie temperature, the heat generated by eddy current losses in the particle shell is reduced due to both the reduced magnetic flux through the particle shell and the reduced effective resistance of the shell material. Furthermore, since hysteresis losses in the particle core disappear at the Curie temperature of the core material, overall heat generation is reduced. Most importantly, when the sensor assembly reaches the Curie temperature of the core material, a reduction in total heat generation is automatically achieved. As a result, rapid overheating of the aerosol-forming matrix can be effectively avoided, preferably eliminating the need for active temperature control.

[0008] Furthermore, the heating efficiency of the composite sensor particles according to the present invention is greater than that of sensor particles made solely of ferromagnetic or ferrimagnetic core materials. This is because most of the heat in the shell material is generated due to enhanced eddy current losses.

[0009] The shell material can be paramagnetic. In this case, heat generation in the conductive shell material is solely caused by eddy currents. Similarly, the shell material can be ferromagnetic or ferrimagnetic. As a result, heat can also be generated in the shell material through hysteresis losses. Advantageously, this increases the heating efficiency of the sensor assembly. Preferably, if magnetic, the Curie temperature of the shell material is preferably lower than or equal to the Curie temperature of the ferromagnetic or ferrimagnetic core material. Advantageously, this ensures that heat generation in the shell material due to hysteresis losses occurs only below or at most at the Curie temperature of the core material, that is, only below or at most at the predetermined operating temperature. The Curie temperature of the shell material may also be higher than the Curie temperature of the ferromagnetic or ferrimagnetic core material.

[0010] The shell material can be one of aluminum, stainless steel, conductive carbon, or bronze. As will be described in more detail below, aluminum is particularly suitable because it allows for sintering at low temperatures, which in turn facilitates the manufacture of composite sensor particles.

[0011] Preferably, the core material is non-conductive. In this case, heat generation in the core material is caused solely by hysteresis losses. As a result, heat generation in the sensor core completely ceases when the Curie temperature of the core material is reached. This proves particularly advantageous for self-regulating temperature control of the sensor assembly. Alternatively, the core material may be conductive.

[0012] As mentioned above, the Curie temperature of the core material preferably corresponds to the predetermined operating temperature of the receptor assembly. The actual operating temperature depends on the specific type of aerosol-forming matrix to be heated. For solid aerosol-forming matrices containing tobacco material, the operating temperature range can be between 200°C and 360°C. For gel-like aerosol-forming matrices, the operating temperature range can be between 160°C and 240°C. Therefore, the Curie temperature range of the core material can be between 160°C and 400°C, particularly between 160°C and 360°C, preferably between 200°C and 360°C, or between 160°C and 240°C.

[0013] The heating efficiency of the sensor assembly increases with higher values ​​of relative permeability. Therefore, the core material can have a relative permeability even higher than 200. Thus, the relative permeability of the core material can be at least 300, or at least 400, or at least 500, or at least 700, particularly at least 1000, preferably at least 10000, or at least 50000, or at least 80000. These values ​​refer to the maximum relative permeability at a frequency of 10 kHz (kilohertz), particularly for frequencies up to 10 kHz (kilohertz) and a temperature of 25 degrees Celsius. As will be further described below, the alternating magnetic field used for the inductive heating sensor assembly can range from 500 kHz (kilohertz) to 30 MHz (megahertz), particularly between 5 MHz (megahertz) and 15 MHz (megahertz), preferably between 5 MHz (megahertz) and 10 MHz (megahertz). For these frequencies, the minimum relative permeability of the core material can be lower. For example, the core material may have a relative permeability of at least 80, particularly at least 100, and preferably at least 120 at a frequency of 7 MHz and a temperature of 25 degrees Celsius. Similarly, the core material may have a relative permeability of at least 40, particularly at least 50, and preferably at least 60 at a frequency of 15 MHz and a temperature of 25 degrees Celsius.

[0014] The core material may include or may be ferrite, particularly ferrite powder. As used herein, ferrite is a ceramic material prepared by mixing and firing a large proportion of iron(III)(Fe2O3) blended with one or more additional metallic elements (such as barium, manganese, nickel, and zinc).

[0015] For example, the core material can be one of manganese magnesium ferrite, nickel zinc ferrite, or cobalt zinc barium ferrite.

[0016] For example, the core material may include Mg x Mn y Fe z O4 type composition or composition thereof, wherein x = 0.4-1.1, y = 0.3-0.9, and z = 1-2, and wherein the atomic fractions x, y, and z of the metal cations Mg, Mn, and Fe balance the total charge of the metal cations with the total charge of the oxygen anions.

[0017] Specifically, the core material may include one of the following or may be one of the following:

[0018] -Mg 0.77 Mn 0.58 Fe 1.65 O4 has a Curie temperature of approximately 270 degrees Celsius;

[0019] -Mg 0.55 Mn 0.88 Fe 1.55 O4; it has a Curie temperature of approximately 262 degrees Celsius;

[0020] -Mg 1.03 Mn 0.35 Fe 1.37 O4; it has a Curie temperature of approximately 190 degrees Celsius.

[0021] As mentioned above, nickel-zinc ferrites may include Ni x Zn 1-x Fe₂O₄ type compositions or compositions thereof, wherein x = 0.3-0.7, and the atomic fractions of the metal cations Ni, Zn, and Fe balance the total charge of the metal cations with the total charge of the oxygen anions. In particular, the inductively heated open-pore ceramic material may include or may be, for example, Ni. 0.5 Zn 0.5 Fe2O4 has a Curie temperature of approximately 258 degrees Celsius.

[0022] As mentioned above, cobalt-zinc-barium ferrites may include Co 1.75 Zn 0.25 Ba2 Fe 12 O 22It may be composed of it, which has a Curie temperature of about 279 degrees Celsius.

[0023] Advantageously, ferrites are easy to manufacture and inexpensive. Furthermore, ferrites are non-conductive. Therefore, heat generation in the core material is solely due to hysteresis losses and is thus self-regulating upon reaching the Curie temperature. Moreover, ferrites are inert and therefore not critical for use in aerosol-generating articles comprising an aerosol-forming matrix.

[0024] The core particles are preferably solid. In particular, the core particles may be spherical. Similarly, the shell particles are preferably solid. In particular, the particles may have spherical shells.

[0025] The equivalent particle diameter of each of the one or more receptor particles can range from 10 micrometers to 500 micrometers, particularly from 20 micrometers to 250 micrometers, and even more particularly from 35 micrometers to 75 micrometers, for example, 55 micrometers. The equivalent sphere diameter is used in combination with irregularly shaped particles and is defined as the diameter of a sphere of equivalent volume. The particle size can depend particularly on the aerosol-forming matrix to be heated. Additionally, for safety reasons, the particle size should be large enough that the receptor particles will not pass through filters in which the receptor particles may be used in aerosol-generating articles. Therefore, the particle diameter of each of the one or more receptor particles can be at least 20 micrometers, preferably at least 35 micrometers.

[0026] Therefore, the equivalent spherical core diameter of the particle core can range from 5 micrometers to 499 micrometers, particularly from 15 micrometers to 220 micrometers, and even more particularly from 30 micrometers to 55 micrometers, for example, 35 micrometers. The equivalent particle diameter can be primarily determined by the equivalent spherical core diameter. Equivalent spherical core diameters in the range of 30 to 55 micrometers are particularly suitable because such particles are small enough to be almost invisible in the matrix, yet still large enough to prevent them from passing through the filter in which the aerosol-generating articles might be used by the sensor particles.

[0027] Due to the flux-enhancing effect of the core material within the shell, the shell thickness can be quite small. Advantageously, this allows for savings in materials and costs used in manufacturing the receptor particles. The shell thickness of the particles can range from 2.5 micrometers to 15 micrometers, particularly between 5 micrometers and 12 micrometers, for example, 10 micrometers. The shell thickness can depend particularly on the material of the particle shell, especially on the induction heating rate and the specific requirements of the material used to produce the shell. For example, for aluminum, the shell thickness can be 10 micrometers, while for steel, the shell thickness can be less than 10 micrometers. Larger shell thicknesses are particularly suitable for particle shells with porous or sintered structures.

[0028] The values ​​above may refer to the average core diameter, average shell thickness, and average particle diameter of all receptor particles in the receptor assembly. Therefore, some receptor particles may have at least one of a smaller core diameter, smaller shell thickness, or smaller particle diameter than other receptor particles in the receptor assembly.

[0029] Preferably, the shell and core of the pellet are in physical contact. This allows for good heat exchange between the shell and core, ensuring that they are at approximately the same temperature.

[0030] The core particles can be sintered. Specifically, the core material can be a sintered material. Sintering is a process of compacting and forming a solid material substance through heat or pressure without melting it to its liquefaction point. Advantageously, sintering allows for the production of core particles with virtually any shape and size. Sintering also results in receptor particles with good strength properties. Furthermore, sintered core particles facilitate good bonding between the core and the shell.

[0031] Therefore, it is preferable that the particle shell is firmly bonded to the particle core. That is, there can be a material-to-material bond between the particle shell and the particle core. A strong bond provides good mechanical stability and good heat exchange between the particle shell and the particle core.

[0032] Specifically, the shell material can be plated, deposited, coated, or encapsulated onto the particle core to form a particle shell.

[0033] The sensor assembly according to the invention is preferably configured to be driven by an alternating, particularly high-frequency, magnetic field. As mentioned herein, the high-frequency magnetic field can range from 500 kHz to 30 MHz, particularly between 5 MHz and 15 MHz, and preferably between 5 MHz and 10 MHz.

[0034] Receptor particles may include a covering, particularly a protective covering. The covering may be formed of glass, ceramic, or inert metal, and may be formed or coated onto at least a portion of the receptor particles. Advantageously, the covering may be configured to: prevent the aerosol-forming matrix from adhering to the surface of the receptor assembly, or conversely increase the adhesion of the aerosol-forming matrix (particularly a liquid aerosol-forming matrix) to the receptor assembly; provide a porous surface (particularly for storing flavor substances or liquid aerosol-forming matrix); provide a flavor substance or aerosol-enhancing covering; prevent material diffusion (e.g., metal diffusion) from the receptor material into the aerosol-forming matrix; or improve the mechanical strength of the receptor particles. To provide a flavor substance or aerosol-enhancing covering, the covering may include a flavor substance or aerosol-enhancing substance. Preferably, the covering is non-conductive.

[0035] As used herein, the term "receptor particle" refers to a component capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This may result from at least one of hysteresis loss or eddy currents induced in the receptor particle, depending on the electrical and magnetic properties of the material incorporated into the receptor particle. In ferromagnetic or ferrimagnetic receptor materials, hysteresis loss occurs due to the switching of magnetic domains within the material under the influence of an alternating electromagnetic field. If the receptor material is conductive, eddy currents can be induced. In the case of conductive ferromagnetic or ferrimagnetic receptor materials, heat can be generated due to both eddy currents and hysteresis loss.

[0036] According to another aspect of the invention, an aerosol generation article is provided for use with an induction-heated aerosol generation apparatus. The article comprises at least one aerosol-forming matrix and a receptor assembly according to the invention and as described herein. One or more receptor particles of the receptor assembly are embedded in the aerosol-forming matrix.

[0037] Receptor particles can be distributed throughout the aerosol-forming matrix. The receptor particles can be distributed equally throughout the aerosol-forming matrix, that is, uniformly. Alternatively, they can be distributed throughout the aerosol-forming matrix as local concentration peaks or according to a concentration gradient (e.g., a distribution gradient from the central axis of the aerosol-forming article to its periphery).

[0038] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming matrix that releases volatile compounds capable of forming aerosols upon heating. Preferably, the aerosol-generating article is a heated aerosol-generating article. That is, the aerosol-generating article comprises at least one aerosol-forming matrix intended to be heated rather than burned in order to release volatile compounds capable of forming aerosols. The aerosol-generating article may be a consumable, particularly a consumable to be discarded after a single use. For example, the article may be a tube comprising a gel-like aerosol-forming matrix to be heated. Alternatively, the article may be a rod-shaped article, particularly a tobacco article, similar to a conventional cigarette.

[0039] As used herein, the term "aerosol forming matrix" refers to a matrix formed by or comprising an aerosol forming material that, upon heating, releases volatile compounds to generate aerosols. The aerosol forming matrix is ​​intended to be heated, rather than burned, to release the volatile compounds that form the aerosols. An aerosol forming matrix can be a solid aerosol forming matrix, a liquid aerosol forming matrix, or a gel-like aerosol forming matrix, or any combination thereof. That is, an aerosol forming matrix may include, for example, both solid and liquid components. An aerosol forming matrix may include tobacco-containing material containing volatile tobacco flavor compounds that are released from the matrix upon heating. Alternatively or additionally, an aerosol forming matrix may include non-tobacco materials. An aerosol forming matrix may also include an aerosol forming agent. Examples of suitable aerosol forming agents are glycerol and propylene glycol. An aerosol forming matrix may also include other additives and ingredients, such as nicotine or flavorings. The aerosol forming matrix can also be a paste-like material, including porous material pouches of the aerosol forming matrix, or loose tobacco mixed with a gelling agent or adhesive, which may include common aerosol forming agents such as glycerol, and is compressed or molded into rods.

[0040] For example, an aerosol-generating article may include the following elements: a matrix element, a support element, a cooling element, and a filter element. All of the aforementioned elements may be arranged sequentially along the length axis of the article in the order described above, with the matrix element located at the distal end of the article and the filter element located at the proximal end. Specifically, the matrix element is located downstream of the support element relative to the airflow passing through the article during use of the system. Each of the aforementioned elements may be substantially cylindrical. In particular, all elements may have the same external cross-sectional shape. Additionally, the elements may be enclosed by an outer packaging to hold the elements together and maintain the desired cross-sectional shape of the rod-shaped article. Preferably, the packaging is made of paper.

[0041] The matrix element preferably includes at least one aerosol-forming matrix to be heated and a receptor assembly, that is, one or more receptor particles embedded in the aerosol-forming matrix.

[0042] The support element may include a hollow cellulose acetate tube with a free-center air passage.

[0043] Aerosol cooling elements can be elements with a large surface area and low suction resistance (e.g., 15 mmWG (millimeter water meter) to 20 mmWG (millimeter water meter)). In use, the aerosol formed by volatile compounds released from the matrix element is drawn through the aerosol cooling element before being delivered to the proximal end of the aerosol-generating article.

[0044] The filter element is preferably used as a mouthpiece, or as part of a mouthpiece together with an aerosol cooling element. As used herein, the term "mouthpiece" refers to a portion of an article through which aerosol exits to form the article.

[0045] According to another example, an aerosol-generating article may include the following elements: a distal support element, a matrix element, a proximal support element, a cooling element, and a filter element. All the aforementioned elements may be arranged sequentially along the length axis of the article in the order described above, wherein the distal support element is located at the distal end of the article, and the filter element is located at the proximal end of the article. That is, the matrix element is located between the proximal and distal support elements. Specifically, the matrix element is located downstream of the proximal support element and upstream of the distal end support element relative to the airflow passing through the article during use. Each of the aforementioned elements may be substantially cylindrical. In particular, all elements may have the same external cross-sectional shape. Additionally, the elements may be surrounded by an outer packaging to hold the elements together and maintain the desired cross-sectional shape of the rod-shaped article. Preferably, the packaging is made of paper.

[0046] The matrix element, cooling element, and filter element may correspond to the respective elements according to the foregoing examples.

[0047] The distal and proximal support elements may include hollow cellulose acetate tubes with a free-center air passage. Alternatively, the distal support element may include a cellulose acetate rod (without a free-center air passage). The cellulose acetate rod may be used to cover and protect the distal tip of the matrix element.

[0048] Other features and advantages of the aerosol-generating articles according to the invention have been described above with respect to the receptor components according to the invention, and are equally applicable.

[0049] According to another aspect of the invention, an aerosol generation system is provided, comprising an aerosol generation article according to the invention and as described herein, and an induction heating aerosol generation apparatus for use with the aerosol generation article.

[0050] As used herein, the term "induction-heated aerosol generating device" describes an electrically operated apparatus capable of interacting with at least one aerosol generating article comprising at least one aerosol-forming matrix to generate an aerosol via an induction-heated sensor assembly and thus the aerosol-forming matrix within the article. Preferably, the aerosol generating device is a suction device for generating an aerosol that can be directly inhaled by a user through the user's mouth. In particular, the aerosol generating device is a handheld aerosol generating device.

[0051] The device may include a receiving cavity for removably receiving at least a portion of the aerosol-generated article.

[0052] An induction heating aerosol generating apparatus may include at least one induction source configured and arranged to generate an alternating magnetic field in a receiving cavity so that, when an article is received in the aerosol generating apparatus, the induction heating aerosol generating aerosol in the article forms a matrix.

[0053] To generate an alternating magnetic field, the induction source may include at least one inductor, preferably at least one induction coil arranged around the receiving cavity. The induction coil may be arranged to surround the sensor assembly, that is, one or more sensor particles, when the article of mass is received in the receiving cavity.

[0054] At least one induction coil may be a helical coil or a planar coil, particularly a disc coil or a curved planar coil. The use of a flat helical coil allows for robust and inexpensive manufacturing of compact designs. The use of a helical induction coil advantageously allows for the generation of a uniform alternating magnetic field. As used herein, "flat helical coil" means a generally planar coil in which the axis of the coil winding is perpendicular to the surface on which the coil is situated. A flat helical induction coil may have any desired shape within the plane of the coil. For example, a flat helical coil may have a circular shape, or it may have a generally oblong or rectangular shape. However, when used herein, the term "flat helical coil" encompasses both planar coils and flat helical coils shaped to conform to a curved surface. For example, the induction coil may be a "curved" planar coil arranged around the circumference of a preferably cylindrical coil support (e.g., a ferrite core). Furthermore, a flat helical coil may comprise, for example, two four-turn flat helical coil layers or a single four-turn flat helical coil layer. The at least one induction coil may be held within either the body or the housing of the aerosol generating apparatus.

[0055] The induction source may include an alternating current (AC) generator. This AC generator may be powered by the power source of the aerosol generating device. The AC generator is operatively coupled to at least one induction coil. Specifically, the at least one induction coil may be an integral part of the AC generator. The AC generator is configured to generate a high-frequency oscillating current to pass through the at least one induction coil to generate an alternating magnetic field. The AC current may be continuously supplied to the at least one induction coil after system activation, or it may be supplied intermittently, for example, on a per-port suction basis.

[0056] Preferably, the sensing source includes a DC / AC converter connected to a DC power supply comprising an LC network, wherein the LC network comprises a series connection of capacitors and inductors.

[0057] The induction source is preferably configured to generate a high-frequency magnetic field. As mentioned herein, the high-frequency magnetic field can range from 500 kHz to 30 MHz, particularly from 5 MHz to 15 MHz, and preferably from 5 MHz to 10 MHz.

[0058] The aerosol generating apparatus may also include a controller configured, preferably in a closed-loop configuration, to control the operation of the heating process, particularly for controlling the heating of the aerosol forming matrix to a predetermined operating temperature. The operating temperature range for heating the aerosol forming matrix is ​​between 200°C and 360°C, particularly between 160°C and 240°C. These temperatures are typical operating temperatures for heating but not burning the aerosol forming matrix.

[0059] The controller may be the overall controller of the aerosol generating apparatus, or a part of the overall controller. The controller may include a microprocessor, such as a programmable microprocessor, microcontroller, or application-specific integrated circuit (ASIC), or other electronic circuitry capable of providing control. The controller may include other electronic components, such as at least one DC / AC inverter and / or power amplifier, such as a Class C power amplifier, or a Class D power amplifier, or a Class E power amplifier. In particular, the sensing source may be part of the controller.

[0060] The aerosol generation device may include a power source, particularly a DC power source, configured to provide a DC power supply voltage and a DC power supply current to the induction source. Preferably, the power source is a battery, such as a lithium iron phosphate battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require charging; that is, the power source may be rechargeable. The power source may have a capacity that allows sufficient energy to be stored for one or more user experiences. For example, the power source may have sufficient capacity to allow continuous aerosol generation in time intervals of approximately six minutes or multiples of six minutes. In another example, the power source may have sufficient capacity to allow a predetermined number of suctions or discrete activation of the induction source.

[0061] The aerosol generating apparatus may further include a flux concentrator arranged around at least a portion of the induction coil and configured to distort the alternating magnetic field of at least one induction source toward the receiving cavity. Thus, when the article is received in the receiving cavity, the alternating magnetic field is distorted toward an inductively heated liquid conduit (if present). Preferably, the flux concentrator comprises a flux concentrator foil, particularly a multilayer flux concentrator foil.

[0062] Other features and advantages of the aerosol generation system according to the invention have been described with respect to the sensor assembly and aerosol generation article according to the invention, and are therefore equally applicable.

[0063] According to the present invention, a method for manufacturing a receptor assembly comprising one or more composite receptor particles for use in an induction-heated aerosol forming matrix is ​​also provided, wherein each of the one or more receptor particles comprises a particle core and a particle shell that fully encapsulates the particle core. The method includes:

[0064] - Provide one or more granular cores comprising or made of ferromagnetic or ferrimagnetic core materials;

[0065] - Encapsulate each of one or more particle cores with a conductive shell material to form a particle shell around each of the one or more particle cores.

[0066] As further described above regarding the sensor assembly according to the invention, the particle core may be a sintered particle core. Therefore, providing one or more particle cores may include:

[0067] - One or more green blanks are formed from ferromagnetic or ferrimagnetic core material, the shape of which corresponds to the shape of the granular core;

[0068] - Sinter one or more green blanks by heating one or more green blanks.

[0069] As further described above regarding the sensor assembly according to the invention, the shell material can be plated, deposited, coated, or encapsulated onto the particle core to form a particle shell. Therefore, encapsulating each of one or more particle cores with a conductive shell material can include plated, deposited, coated, or encapsulated onto one or more particle cores. In particular, the conductive shell material can be applied to the particle core by vapor deposition, in a slurry, or by rolling in a horizontal fluid bath, wherein the slurry and horizontal fluid bath comprise the shell material to be applied.

[0070] Other features and advantages of the method according to the invention have been described above with respect to the receptor assembly according to the invention, and are equally applicable.

[0071] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0072] Example Ex1: A receptor assembly for induction heating aerosol formation matrix under the influence of an alternating magnetic field, the receptor assembly comprising one or more composite receptor particles, wherein each of the one or more receptor particles comprises a particle core and a particle shell completely encapsulating the particle core, wherein the particle core comprises or is made of a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a frequency of 10 kHz (kilohertz), particularly for frequencies up to 10 kHz (kilohertz), and at a temperature of 20 degrees Celsius, and wherein the particle shell comprises or is made of a conductive shell material.

[0073] Example Ex2: The sensor assembly according to Example Ex1, wherein the shell material is paramagnetic.

[0074] Example Ex3: A sensor assembly according to any of the preceding examples, wherein the shell material is one of aluminum, stainless steel, conductive carbon, or bronze.

[0075] Example Ex4: A sensor assembly according to any of the preceding examples, wherein the core material is non-conductive.

[0076] Example Ex5: A sensor assembly according to any of the foregoing examples, wherein the Curie temperature of the core material is between 160 degrees Celsius and 400 degrees Celsius, particularly between 160 degrees Celsius and 360 degrees Celsius, preferably between 200 degrees Celsius and 360 degrees Celsius, or between 160 degrees Celsius and 240 degrees Celsius.

[0077] Example Ex6: A sensor assembly according to any of the preceding examples, wherein the core material is ferrite powder.

[0078] Example Ex7: A sensor assembly according to any of the preceding examples, wherein the core material is manganese magnesium ferrite, nickel zinc ferrite or cobalt zinc barium ferrite.

[0079] Example Ex8: According to any of the preceding examples, each of the one or more receptor particles is substantially spherical.

[0080] Example Ex9: A receptor assembly according to any of the preceding examples, wherein the equivalent spherical particle diameter of each of the one or more receptor particles is in the range of 10 micrometers to 500 micrometers, particularly between 20 micrometers and 250 micrometers, and more particularly between 35 micrometers and 75 micrometers, for example 55 micrometers.

[0081] Example Ex10: A sensor assembly according to any of the foregoing examples, wherein the equivalent spherical core diameter of the particle core is in the range of 5 micrometers to 499 micrometers, particularly between 15 micrometers and 220 micrometers, and even more particularly between 30 micrometers and 55 micrometers, for example 35 micrometers.

[0082] Example Ex11: The sensor assembly according to any of the foregoing examples, wherein the shell thickness of the particle shell is in the range of 1 micrometer to 100 micrometers, particularly between 2.5 micrometers and 15 micrometers, more particularly between 5 micrometers and 12 micrometers, for example 10 micrometers.

[0083] Example Ex12: A sensor assembly according to any of the foregoing examples, wherein the particle core is a sintered particle core, and in particular, wherein the core material is a sintered material.

[0084] Example Ex13: A sensor assembly according to any of the preceding examples, wherein the particle shell is in physical contact with the particle core.

[0085] Example Ex14: A sensor assembly according to any of the preceding examples, wherein the particle shell is firmly bonded to the particle core.

[0086] Example Ex15: A sensor assembly according to any of the preceding examples, wherein the shell material is coated, deposited, coated or encapsulated onto the particle core to form the particle shell.

[0087] Example Ex16: An aerosol generating article for use with an induction heating aerosol generating apparatus, wherein the article comprises at least one aerosol forming matrix and a receptor assembly according to any of the foregoing examples, wherein one or more receptor particles of the receptor assembly are embedded in the aerosol forming matrix, particularly distributed throughout the aerosol forming matrix, for example, uniformly distributed, or distributed with local concentration peaks, or distributed with a distribution gradient particularly from the central axis of the aerosol forming article to its periphery.

[0088] Example Ex17: An aerosol generation system comprising an aerosol generation article according to any of the foregoing examples, and an induction heating aerosol generation apparatus for use with the aerosol generation article.

[0089] Example Ex18: A method for manufacturing a receptor assembly comprising one or more composite receptor particles for use in an induction-heated aerosol forming matrix, wherein each of the one or more receptor particles comprises a particle core and a particle shell that fully encapsulates the particle core, the method comprising:

[0090] - Provide one or more granular cores comprising or made of ferromagnetic or ferrimagnetic core materials;

[0091] - Each of the one or more particle cores is encapsulated with a conductive shell material to form a particle shell around each of the one or more particle cores.

[0092] Example Ex19: According to the method of Example Ex18, providing the one or more particle cores includes:

[0093] - One or more green blanks are formed from ferromagnetic or ferrimagnetic core material, the shape of which corresponds to the shape of the granular core;

[0094] - Sinter the one or more green blanks by heating them.

[0095] Example Ex20: The method according to any one of Examples Ex18 or Ex19, wherein encapsulating each of the one or more particle cores with a conductive shell material includes plating, depositing, coating or covering the shell material onto the one or more particle cores.

[0096] Example Ex21: The method according to any one of Examples Ex18 to Ex20, wherein encapsulating each of the one or more particle cores with a conductive shell material comprises applying the shell material to the particle core by vapor deposition, in a slurry, or by rolling in a flat fluid bath, wherein the slurry and the flat fluid bath comprise the shell material to be applied. Attached Figure Description

[0097] Several examples will now be described further with reference to the accompanying drawings, in which:

[0098] Figure 1 The illustration schematically shows a heatable aerosol-generating article according to a first exemplary embodiment of the present invention, including a sensor assembly;

[0099] Figure 2 The diagram schematically illustrates an aerosol generating device and, according to... Figure 1 Exemplary embodiments of an aerosol generation system for aerosol-generated articles;

[0100] Figure 3 It shows that it includes according to Figure 1 A receptor particle in a receptor assembly of an aerosol-generating article; and

[0101] Figure 4 An inductively heated aerosol generating article according to a second exemplary embodiment of the present invention is illustrated schematically. Detailed Implementation

[0102] Figure 1A first exemplary embodiment of an inductively heated aerosol-generating article 100 according to the present invention is schematically shown. The aerosol-generating article 100 is substantially rod-shaped and includes four elements arranged sequentially and coaxially: an aerosol-forming rod segment 110, a support element 140 having a central air passage 141, an aerosol cooling element 150, and a filter element 160 serving as a mouthpiece. The aerosol-forming rod segment 110 is disposed at the distal end 102 of the article 100, while the filter element 160 is disposed at the distal end 103 of the article 100. Each of the four elements is substantially cylindrical, and they all have substantially the same diameter. Furthermore, the four elements are surrounded by an outer packaging material 170 to hold the four elements together and maintain the desired circular cross-sectional shape of the rod-shaped article 100. The packaging material 170 is preferably made of paper.

[0103] Regarding the present invention, the aerosol forming rod segment 110 includes an aerosol forming matrix 130 and a receptor assembly 120 for heating the matrix 130 when exposed to an alternating magnetic field. For example... Figure 1 As can be seen, the receptor assembly 120 includes a plurality of receptor particles 123 equally distributed throughout the aerosol-forming matrix 130. Due to their particulate nature, the receptor particles 123 exhibit a large surface area over the surrounding aerosol-forming matrix 130, which advantageously enhances heat transfer. Reference will be made below. Figure 3 To further describe the details of receptor particle 123 in more detail.

[0104] like Figure 2 As shown, the aerosol generating article 100 is configured for use with an induction-heated aerosol generating apparatus 10. The apparatus 10 and the article 100 together form an aerosol generating system 1 according to the invention. The aerosol generating apparatus 10 includes a cylindrical receiving cavity 20 defined within a proximal portion 12 of the apparatus 10 for receiving at least a distal portion of the article 100 therein. The apparatus 10 further includes an induction source comprising an induction coil 30 for generating an alternating high-frequency magnetic field. In this embodiment, the induction coil 30 is a helical coil circumferentially surrounding the cylindrical receiving cavity 20. The coil 30 is arranged such that the sensor assembly 120 of the aerosol generating article 100 experiences an alternating magnetic field when the article 100 is engaged with the apparatus 10. Therefore, when the induction source is activated, the sensor assembly 120 is heated due to induction heating. As will be discussed below regarding... Figure 3 In further detail 123, the sensor assembly 120 is heated until it reaches an operating temperature sufficient to evaporate the aerosol forming matrix 130 in the aerosol forming rod segment 110. Within the distal portion 13, the aerosol generating apparatus 10 also includes a DC power supply 40 and a controller 50 (only in...). Figure 2(Illustrated schematically) for supplying power to the heating process and controlling the heating process. In addition to the induction coil 30, the induction source is preferably at least partially integrated into the controller 50 of the device 10.

[0105] Figure 3 It shows the way Figure 1 The image shows a detailed cross-sectional view of one of the receptor particles 123 used within the aerosol-generating article. According to the invention, each receptor particle in the receptor particles 123 includes a particle core 121 and a particle shell 122 that completely encapsulates the particle core 121. The particle core 121 comprises, or is made of, a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a temperature of 20 degrees Celsius for frequencies up to 10 kHz (kilohertz). In this embodiment, the particle core 121 is made of nickel-zinc ferrite, that is, of a non-conductive ferrimagnetic material. In contrast, the particle shell 122 is made of a conductive shell material. In this embodiment, the particle shell 122 is made of paramagnetic aluminum. Therefore, generally, when exposed to the alternating magnetic field of the induction coil 32, the particle shell 122 heats up due to eddy currents, while the particle core 121 heats up due to hysteresis losses.

[0106] According to the invention, the magnetic core has another important function: due to its high permeability, the particle 121 acts as a flux concentrator that increases the magnetic flux through the particle shell 122. According to Faraday's law of induction, the increase in magnetic flux leads to an increase in eddy current losses in the particle shell 122. Therefore, the high permeability of the magnetic particle core 121 increases the heat generated in the particle shell during use. Advantageously, this also allows for a thinner particle shell, and thus saves on materials and costs used in manufacturing the sensor particles.

[0107] When the core material reaches approximately its Curie temperature, the magnetic properties of the core 121 change from ferrimagnetic to paramagnetic. As a result, the overall effective permeability of the magnetic core 121 decreases to a uniform level. With the disappearance of hysteresis in the core material, heat generation in the core 121 ceases. More importantly, the change in permeability also affects heat generation in the shell 122, because the decrease in the permeability of the magnetic core 121 reduces the magnetic flux through the conductive shell 122. This, in turn, leads to a decrease in electromotive force when the sensor assembly reaches the Curie temperature of the core material, and consequently, a decrease in eddy current losses due to heat generation in the shell 122.

[0108] Furthermore, as further described above, the decrease in permeability increases the skin depth in the particle shell 122, thus affecting heat generation in the particle shell 122. This, in turn, reduces the effective resistance of the aluminum particle shell 122. Therefore, when the Curie temperature of the core material is reached, the decrease in effective resistance also reduces eddy current losses in the shell material, thereby reducing heat generation in the particle shell 122.

[0109] Therefore, at the Curie temperature, the heat generated by eddy current losses in the particle shell 122 is reduced due to both the decrease in magnetic flux through the particle shell and the decrease in the effective resistance of the shell material. Furthermore, since the hysteresis losses in the particle core 121 disappear at the Curie temperature of the core material, overall heat generation is reduced. In particular, the automatic reduction in total heat generation effectively prevents rapid overheating of the aerosol-forming matrix, preferably eliminating the need for active temperature control.

[0110] Preferably, a specific core material is selected to have a Curie temperature approximately at a predetermined operating temperature of the receptor assembly 120, which will heat the aerosol forming matrix 130. For solid aerosol forming matrices containing tobacco material, the operating temperature range can be between 200 degrees Celsius and 360 degrees Celsius.

[0111] like Figure 3 As further observed, the receptor particles 123 are substantially spherical. The particle diameter 124 can range from 50 micrometers to 75 micrometers. In this embodiment, the average particle diameter of all receptor particles 123 is about 555 micrometers, which is generated by a particle core 121 having a core diameter 125 of about 35 micrometers and a particle shell 122 having a shell thickness 126 of about 10 micrometers.

[0112] The particle core can be manufactured by sintering a green blank of ferromagnetic or ferrimagnetic core material and then applying a shell material to the particle core 121, for example by vapor deposition, in order to provide a particle shell 122 that is firmly bonded to the particle core 121.

[0113] Figure 4 A second embodiment of the aerosol-generating article 200 according to the present invention is shown. Generally, according to Figure 4 Aerosol-generating products 200 and Figure 1 and 2 The aerosol-generating article 100 shown is very similar. Therefore, identical or similar features are indicated by the same reference numerals, only incremented by 100. Figure 1 Compared to the first embodiment shown, according to Figure 4The article 400 has a particle distribution of receptor particles 223 with a distribution gradient from the central axis 207 of the aerosol forming article 200 to its periphery (in particular with local concentration maximum along the central axis 207 of the article 200) so that the aerosol forming matrix 230 is heated mainly in the central portion of the rod segment 210.

[0114] For the purposes of this specification and the appended claims, unless otherwise stated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term "about" in all cases. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 5% A. In this context, the number A can be considered as a value within the general standard error for the measurement of the attribute modified by the number A. In some cases as used in the appended claims, the number A may deviate from the percentages listed above, provided that the amount of deviation from A does not significantly affect the fundamental and novel features of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein.

Claims

1. A sensor assembly for inductively heating an aerosol-forming matrix under the influence of an alternating magnetic field, the sensor assembly comprising one or more composite sensor particles, each of the one or more composite sensor particles comprising a particle core and a particle shell completely encapsulating the particle core, wherein the particle core comprises or is made of a ferromagnetic or ferrimagnetic core material having a relative permeability of at least 200 at a frequency of up to 10 kHz and at a temperature of 20 degrees Celsius, and wherein the particle shell comprises or is made of a conductive shell material.

2. The receptor assembly of claim 1, wherein the shell material is paramagnetic.

3. The receptor assembly according to claim 1 or 2, wherein the shell material is one of aluminum, stainless steel, conductive carbon, or bronze.

4. The sensor assembly according to claim 1 or 2, wherein the core material is non-conductive.

5. The receptor assembly according to claim 1 or 2, wherein the Curie temperature of the core material is between 160 degrees Celsius and 400 degrees Celsius.

6. The receptor assembly of claim 5, wherein the Curie temperature of the core material is between 160 degrees Celsius and 360 degrees Celsius.

7. The receptor assembly of claim 6, wherein the Curie temperature of the core material is in the range of 200 degrees Celsius to 360 degrees Celsius.

8. The receptor assembly of claim 6, wherein the Curie temperature of the core material is in the range of 160 degrees Celsius to 240 degrees Celsius.

9. The sensor assembly according to claim 1 or 2, wherein the core material is ferrite powder.

10. The sensor assembly according to claim 1 or 2, wherein the core material is manganese magnesium ferrite, nickel zinc ferrite or cobalt zinc barium ferrite.

11. The receptor assembly according to claim 1 or 2, wherein each of the one or more composite receptor particles is substantially spherical.

12. The receptor assembly of claim 1 or 2, wherein the equivalent spherical particle diameter of each of the one or more composite receptor particles ranges from 10 micrometers to 500 micrometers.

13. The receptor assembly of claim 12, wherein the equivalent spherical particle diameter of each of the one or more composite receptor particles ranges from 20 micrometers to 250 micrometers.

14. The receptor assembly of claim 13, wherein the equivalent spherical particle diameter of each of the one or more composite receptor particles ranges from 35 micrometers to 75 micrometers.

15. The receptor assembly of claim 14, wherein the equivalent spherical particle diameter of each of the one or more composite receptor particles is 55 micrometers.

16. The receptor assembly according to claim 1 or 2, wherein the equivalent spherical core diameter of the particle core ranges from 5 micrometers to 499 micrometers.

17. The sensor assembly of claim 16, wherein the equivalent spherical core diameter of the particle core ranges from 15 micrometers to 220 micrometers.

18. The receptor assembly of claim 17, wherein the equivalent spherical core diameter of the particle core ranges from 30 micrometers to 55 micrometers.

19. The sensor assembly of claim 18, wherein the equivalent spherical core diameter of the particle core is 35 micrometers.

20. The receptor assembly according to claim 1 or 2, wherein the shell thickness of the particle shell is in the range of 1 micrometer to 100 micrometers.

21. The receptor assembly of claim 20, wherein the shell thickness of the particle shell is in the range of 2.5 micrometers to 15 micrometers.

22. The sensor assembly of claim 21, wherein the shell thickness of the particle shell is in the range of 5 micrometers to 12 micrometers.

23. The receptor assembly of claim 22, wherein the shell thickness of the particle shell is 10 micrometers.

24. The sensor assembly according to claim 1 or 2, wherein the particle core is a sintered particle core.

25. The sensor assembly of claim 24, wherein the core material is a sintered material.

26. The receptor assembly of claim 1 or 2, wherein the shell material is coated, deposited, coated or encapsulated onto the particle core to form the particle shell.

27. An aerosol generating article for use with an induction heating aerosol generating apparatus, wherein the aerosol generating article comprises at least one aerosol forming matrix and a receptor assembly according to any one of claims 1 to 26, wherein the one or more composite receptor particles of the receptor assembly are embedded in the aerosol forming matrix.

28. The aerosol-generating article of claim 27, wherein the one or more composite receptor particles of the receptor assembly are distributed throughout the aerosol-forming matrix.

29. The aerosol-generating article of claim 27 or 28, wherein the one or more composite receptor particles of the receptor assembly are distributed throughout the aerosol-forming matrix in a distribution gradient from the central axis of the aerosol-generating article to the periphery of the aerosol-generating article.

30. An aerosol generation system comprising an aerosol generation article according to any one of claims 27 to 29, and an induction heating aerosol generation apparatus for use with said aerosol generation article.

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