Susceptor for use in an induction heating aerosol generator or system

Abstract

The present invention relates to an inductively heated susceptor (210) for use in an inductively heated aerosol generating device or system (100). The susceptor (210) comprises an open-porous, inductively heatable ceramic material for holding an aerosol-forming liquid (202) and heating the aerosol-forming liquid (202) under the influence of an alternating electromagnetic field. The present invention further relates to a cartridge (200) for use in an aerosol-generating device (100). The cartridge (200) comprises an aerosol-forming liquid (202) and a susceptor (210) of the present invention for holding at least a portion of the aerosol-forming liquid (202). The present invention further relates to an aerosol-generating device (100) for generating an aerosol by inductively heating the aerosol-forming liquid (202), the device comprising a susceptor (210) of the present invention.

Description

Technical Field

[0001] The present invention relates to a susceptor for holding and inductively heating an aerosol-forming liquid. The present invention further relates to a cartridge for use in an aerosol-generating device, and an aerosol-generating device and system for generating an aerosol by inductively heating an aerosol-forming liquid.

Background Art

[0002] Aerosol-generating systems based on the inductive heating of an aerosol-forming substrate are generally known from the prior art. These systems may comprise an induction source for generating an alternating electromagnetic field that induces at least one of eddy currents or hysteresis losses that generate heat within the susceptor. The susceptor thus heated is in thermal proximity to an aerosol-forming substrate that can release volatile compounds upon heating to form an aerosol. Depending on the type of aerosol-generating system, the susceptor and the aerosol-forming substrate may be provided together within an aerosol-generating article, particularly within a cartridge. The cartridge may be configured to be received within a recess of an aerosol-generating device that includes an induction source. Several susceptor configurations have been described in the art to ensure proper heating of the aerosol-forming substrate. However, in many cases, the susceptor only contacts a small portion of the aerosol-forming substrate. This can lead to non-uniform heating across the substrate volume such that the temperature of the substrate is partially too low to form an aerosol. As a result, only a small portion of the substrate is effectively utilized for the user experience. However, increasing the heating power to heat all parts of the substrate to the temperature required for aerosol formation may cause local overheating of those parts that are in direct contact with the susceptor.

[0003] Accordingly, it is desirable to have a susceptor, as well as a cartridge and an aerosol generating device comprising the susceptor, that have the advantages of prior art solutions but do not stop there. In particular, it is desirable to have a susceptor, cartridge and aerosol generating device that enable homogeneous heating of the aerosol-forming substrate without the risk of local overheating. SUMMARY OF THE INVENTION

[0004] According to the present invention, an induction heating susceptor for use in an aerosol generating device or system is provided. The susceptor comprises an open-porous induction heating ceramic material for holding an aerosol-forming liquid and heating the liquid under the influence of an alternating electromagnetic field. In particular, the susceptor may be made of or consist of this open-porous ceramic material.

[0005] The ceramic material according to the present invention can be characterized on the one hand by its open porosity or open pore structure and on the other hand by its ability to be heated under the influence of an alternating electromagnetic field. Thereby, the susceptor is advantageously both a storage medium for the aerosol-forming liquid to be heated and a heating element for inductively heating the liquid held therein. For this reason, the susceptor according to the present invention can be considered a dual-function susceptor. Advantageously, the open-porous structure of the ceramic material allows the entire susceptor material to be uniformly immersed in the aerosol-forming liquid. Accordingly, the susceptor is in direct contact with the aerosol-forming liquid throughout. At the same time, the entire volume of the susceptor can be heated homogeneously under the influence of an alternating electromagnetic field. For this reason, the susceptor according to the present invention can advantageously heat the entire aerosol-forming liquid stored therein homogeneously without the need to overheat. Furthermore, the susceptor according to the present invention can advantageously ensure a very consistent user experience because the amount of aerosol-forming liquid that can be heated is related to the porosity and total volume of the susceptor, which are well-controlled parameters.

[0006] The open porosity of the susceptor provides a high holding capacity for the liquid aerosol-forming material. Thus, the liquid aerosol-forming material is safely maintained or held within the susceptor. Advantageously, this reduces the risk of leakage, for example as compared to a liquid tank. In particular, this enables the susceptor and any aerosol-generating article, device or system comprising such a susceptor to be leak-proof. Furthermore, the open porosity of the susceptor material allows the aerosol-forming material vaporized upon heating to escape freely from the cartridge.

[0007] As used herein, the term "susceptor" means an element comprising a material capable of converting electromagnetic energy into heat. Thus, when positioned within an alternating electromagnetic field, the susceptor is heated. Generally, this can be the result of hysteresis losses and / or eddy currents induced within the susceptor, depending on the electrical and magnetic properties of the susceptor material. Hysteresis losses occur in ferromagnetic or ferrimagnetic susceptor materials by magnetic domains within the material that are switched under the influence of an alternating electromagnetic field. Eddy currents can be induced when the susceptor material is conductive. In the case of a conductive ferromagnetic or ferrimagnetic susceptor material, heat can be generated by both eddy currents and hysteresis losses. Thus, the open-porous induction-heating ceramic material according to the invention can be heated by at least one of hysteresis losses or eddy currents, depending on the electrical and magnetic properties of the open-porous ceramic material. Thus, the open-porous induction-heating ceramic material can be conductive. Alternatively or additionally, the open-porous induction-heating ceramic material may be ferromagnetic or ferrimagnetic. For example, the susceptor may comprise or consist of a conductive ceramic material such as lanthanum-doped strontium titanate or yttrium-doped strontium titanate. Similarly, the susceptor may comprise or consist of an open-porous ferromagnetic or ferrimagnetic ceramic material such as ceramic ferrite.

[0008] As used herein, the term "aerosol-forming liquid" relates to a liquid capable of releasing a volatile compound that can form an aerosol upon heating of the aerosol-forming liquid. The aerosol-forming liquid can include both solid and liquid aerosol-forming materials or components. The aerosol-forming liquid may include a tobacco-containing material that includes a volatile tobacco flavor compound released from the liquid upon heating. Alternatively, or in addition, the aerosol-forming substrate may include a non-tobacco material. The aerosol-forming liquid may further include an aerosol-forming body. Examples of suitable aerosol-forming bodies are glycerin and propylene glycol. The aerosol-forming substrate may also include other additives and components such as nicotine or flavorants. In particular, the aerosol-forming liquid may include water, a solvent, ethanol, a plant extract, and a natural or artificial flavor. The aerosol-forming liquid may also be a paste-like material, a sachet of a porous material containing the aerosol-forming substrate, or loose tobacco mixed with, for example, a gelling agent or an adhesive, which can include a common aerosol-forming body such as glycerin and is then compressed or formed into a plug.

[0009] The specific material and geometric shape of the susceptor can be selected to provide the desired heat generation and liquid absorption and retention effects. Generally, the susceptor can have any desired shape. The shape can be dependent on the particular operation and installation location when used in an aerosol-generating article, device or system. For example, the susceptor can be one of a cylindrical, disc, tube, cube or washer-shaped configuration.

[0010] The susceptor may be a single body that includes or is made of an open-porous induction-heatable ceramic material. The single body may be a compact solid body. This configuration advantageously enables the provision of a compact single storage medium for the aerosol-forming liquid to be heated. In particular, the single susceptor body may be a single pellet or a pressed article.

[0011] Alternatively, the susceptor may comprise a plurality of susceptor elements, each susceptor element comprising or consisting of an open porous induction heating ceramic material. Similarly, each susceptor element may be a single unit, particularly a compact solid body. For example, the susceptor may be a solid bulk material of individual susceptor elements such as individual susceptor pellets. The susceptor may be susceptor fines.

[0012] The amount of aerosol-forming liquid held and heated by the susceptor is related to the porosity of the open porous ceramic material. The open porous induction heating ceramic material preferably has a porosity of 20% to 60%. This range of porosity is advantageous with respect to the amount of aerosol-forming liquid held and heated by the susceptor to provide a convenient user experience. The porosity can be selected such that the susceptor holds a predetermined amount of aerosol-forming liquid. The predetermined amount of liquid preferably corresponds to a predetermined number of puffs available when using the susceptor in an aerosol-generating device or system. Also, the porosity can be selected with respect to a particular airflow management through the susceptor. For example, the porosity can be selected to provide a particular draw resistance (RTD).

[0013] Heating of the aerosol-forming liquid is preferably based solely on hysteresis losses. Thus, heating of the susceptor, i.e., heating of the open porous induction heating ceramic material, may be mainly due to or solely due to hysteresis losses. Accordingly, the open porous ceramic material is preferably only ferromagnetic or ferrimagnetic. Thus, the open porous induction heating ceramic material is preferably non-conductive or, if conductive, has a very weak conductivity. As will be explained in more detail below, this may be desirable to limit the heatability of the susceptor to a temperature corresponding to the Curie temperature of the susceptor material. In non-conductive materials, eddy currents and heating due to eddy currents do not occur.

[0014] Ferromagnetic and ferrimagnetic materials are characterized by retaining spontaneous magnetization below the Curie temperature and not exhibiting magnetic order above this temperature. Thus, above their Curie temperature, ferromagnetic or ferrimagnetic materials become paramagnetic and no longer exhibit hysteresis losses. Therefore, if the open-porous ceramic material of the susceptor is non-conductive but only ferromagnetic or ferrimagnetic, its induction heating property completely disappears above the Curie temperature. This effect can be advantageously used to control the heating temperature of the susceptor. Thus, the open-porous induction heating ceramic material of the susceptor may have a Curie temperature selected to correspond to the maximum temperature to which the susceptor is heated, in order to avoid or at least reduce the possibility of rapid overheating. The Curie temperature can deviate from this maximum temperature by about 1% to 3%. The induction heating ceramic material of the susceptor may be selected to have a Curie temperature lower than 400 °C, preferably lower than 380 °C, or preferably lower than 360 °C. The induction heating ceramic material preferably has a Curie temperature of 150 °C to 300 °C. This is particularly applicable to a susceptor containing only a single ferromagnetic ceramic material.

[0015] As described above, the open-porous induction heating ceramic material is preferably a ceramic ferrite. As used herein, ferrite is a metal oxide such as hematite (Fe2O3) or magnetite (Fe3O4), as well as a ferrimagnetic ceramic compound derived from other metals. Usually, ferrite is non-conductive.

[0016] In particular, the open-porous induction heating ceramic material - contains at least one of manganese magnesium ferrite, - nickel zinc ferrite, or - cobalt zinc barium ferrite, or is at least one of them.

[0017] The above-mentioned nickel zinc ferrite is Mg x Mn yFe z It may contain or consist of an O4-type composition, where x = 0.4 - 1.1, y = 0.3 - 0.9, z = 1 - 2, and the atomic fractions x, y, and z of the metal cations Mg, Mn, and Fe are such that the total charge of the metal cations balances the total charge of the oxygen anions. In particular, the open-porous induction heating ceramic material is - having a Curie temperature of about -270 °C, Mg 0.77 Mn 0.58 Fe 1.65 O4, - having a Curie temperature of about -262 °C, Mg 0.55 Mn 0.88 Fe 1.55 O4, - having a Curie temperature of about -190 °C, Mg 1.03 Mn 0.35 Fe 1.37 O4, and may contain at least one of them, or may be at least one of them.

[0018] The above nickel zinc ferrite may contain or consist of a Ni x Zn 1-x Fe2O4-type composition, where x = 0.3 - 0.7, and the atomic fractions of the metal cations Ni, Zn, and Fe are such that the total charge of the metal cations balances the total charge of the oxygen anions. In particular, the open-porous induction heating ceramic material may contain, for example, Ni 0.5 Zn 0.5 Fe2O4 having a Curie temperature of about 258 °C, or may be it.

[0019] As described above, the cobalt zinc barium ferrite has a Curie temperature of about 279 °C, Co 1.75 Zn 0.25 Ba2Fe 12 O 22 and may contain or consist of it.

[0020] A method for manufacturing a susceptor containing the open-porous induction heating ceramic material according to the present invention is as follows: - Mixing the powdered raw components of the ceramic material; - Dissolving cellulose in a solvent; - Mixing the dissolved cellulose with the mixed raw components to obtain a slurry mixture; - Drying the slurry mixture; - Pressing the dried mixture to form pellets of a desired shape; - Firing the pellets to form open-porous pellets; - Annealing the open-porous pellets, may be included.

[0021] The step of mixing the powdered raw components of the ceramic material and the step of mixing the dissolved cellulose with the mixed raw components may be combined, i.e., the raw components of the ceramic material and the dissolved cellulose may be mixed together in one step.

[0022] Instead of using a solvent, the treatment of cellulose and the powdered raw material may alternatively be carried out in a dry state. Thus, an alternative method for manufacturing a susceptor containing an open-porous induction heating ceramic material according to the present invention may include the following: - Mixing the powdered raw components of the ceramic material and cellulose to obtain a dry mixture; - Pressing the dry mixture to form pellets of a desired shape; - Firing the pellets to form open-porous pellets; - Annealing the open-porous pellets, may be included.

[0023] As used herein, "firing" refers to a heat treatment process in an air or oxygen atmosphere at a temperature of 550°C to 1300°C. Firing can be carried out in a firing furnace. The firing furnace may be a steel cylinder that rotates within a heating furnace and performs indirect high-temperature treatment within a controlled atmosphere. Regarding the ceramic material according to the present invention, firing aims to burn cellulose and, if present, to remove the solvent. During this process, the desired open-porous structure of the ceramic material is formed. The pellets are preferably fired at a temperature of about 1200°C.

[0024] Cellulose has two functions. First, cellulose acts as a binder between the particles of the mixed raw components within the pellet. Second, the cellulose particles advantageously act as a displacer for forming an open-porous structure.

[0025] The pressure applied to the dried mixture to form pellets of the desired shape can range from 5 to 10 t / cm 2 (tons per square centimeter). For example, a load of 10 tons may be applied to a circular sample having a diameter of 13 mm.

[0026] The open-porous pellets are preferably annealed at a temperature in the range of 500°C to 700°C, particularly at a temperature of about 600°C.

[0027] Before the step of mixing the powdered raw components, the method may further include the step of sieving the raw components of the ceramic material to select powdered particles of the raw components having a specific particle size within a desired range. The specific particle size is preferably 50 μm to 80 μm.

[0028] The method may further include the step of pulverizing the raw components before mixing the raw components and, if provided, before sieving the raw components.

[0029] After the grinding step, the method may further include a step of drying the ground raw components before mixing the raw components and, if provided, before sieving the raw components.

[0030] The susceptor may be part of a consumable aerosol-generating article that is pre-impregnated with an aerosol-forming liquid or may be a consumable aerosol-generating article, so as to be prepared for use in an aerosol-generating device comprising an induction source. Thus, the susceptor may further comprise an aerosol-forming liquid retained within an open-porous induction-heating ceramic material. That is, the susceptor may comprise an open-porous induction-heating ceramic material that retains or is (pre-)impregnated with an aerosol-forming liquid. In particular, the open-porous induction-heating ceramic material may be retained or (pre-)impregnated with a predetermined amount of aerosol-forming liquid. The predetermined amount of liquid preferably corresponds to a predetermined number of inhalations made available when using the susceptor in an aerosol-generating device.

[0031] In another way, the susceptor may be an integral part of the aerosol-generating device. Accordingly, the present invention also provides an aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming liquid. The aerosol-generating device comprises an induction source including an induction coil for generating an alternating electromagnetic field. Further, the device comprises a susceptor according to and as described herein in the present invention, including an open-porous induction-heating ceramic material for holding and heating the aerosol-forming liquid. The susceptor is arranged relative to the induction coil so as to be inductively heated by the alternating electromagnetic field during operation of the device.

[0032] To generate an alternating electromagnetic field, the induction source may include an alternating current (AC) generator. The AC generator may be powered by the power supply of the aerosol generator. The AC generator is operably connected to an induction coil. The AC generator is configured to generate a high-frequency oscillating current that passes through the induction coil to generate an alternating electromagnetic field. As used herein, the term high-frequency oscillating current means an oscillating current having a frequency of 500 kHz to 30 MHz, preferably 1 MHz to 10 MHz, more preferably 5 MHz to 7 MHz.

[0033] The device may further comprise an electrical circuit, preferably including an AC generator. The electrical circuit can advantageously comprise a DC / AC inverter, which may include a class D or class E power amplifier. The electrical circuit may be connected to the power supply of the aerosol generator. The electrical circuit comprises a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application-specific integrated circuit (ASIC) or other electronic circuit having control capabilities. The electrical circuit may comprise further electronic components. The electrical circuit may be configured to regulate the current supply to the induction coil. The current can be supplied continuously to the induction coil after startup of the system, or intermittently (e.g., with each inhalation).

[0034] As described above, the aerosol generator advantageously comprises a power supply, preferably a battery such as a lithium iron phosphate battery. Alternatively, the power supply may be another form of charge storage device such as a capacitor. The power supply may need to be recharged and may have a capacity that allows sufficient energy storage for one or more user experiences. For example, the power supply may have a capacity sufficient to allow continuous generation of aerosol for about 6 minutes, or a multiple of 6 minutes. In another example, the power supply may have a capacity sufficient to allow a predetermined number of inhalations, or discontinuous activation of the induction coil.

[0035] The device may comprise a single induction coil or a plurality of induction coils. The number of induction coils may depend on the number of susceptor elements. The induction coil(s) may have a shape that conforms to the shape of the susceptor. Similarly, the induction coil(s) may have a shape that fits the shape of the housing of the aerosol generating device. For example, the induction coil(s) may be a helical coil or a flat spiral coil. The induction coil may be wound around a ferrite core. When used herein, the term "flat spiral coil" generally means a planar coil in which the axis of the coil winding is perpendicular to a surface on which the coil lies. The flat spiral induction may have any desired shape within the plane of the coil. For example, the flat spiral coil may have a circular shape or generally an oval or rectangular shape. However, when used herein, the term "flat spiral coil" encompasses not only planar coils but also flat spiral coils having a shape that conforms to a curved surface. The use of flat spiral coils enables the design of a compact device with a robust and inexpensive-to-manufacture simple design. The coil can be held within the housing of the device so as to prevent deposits on the coil and potential corrosion and need not be exposed to the generated aerosol. The induction coil may be covered by a corrosion-resistant coating or enclosure. The diameter of the induction coil may be 5 mm to 10 mm. The induction coil may be arranged on or adjacent to the surface of the recess closest to the power supply. This reduces the amount and complexity of the electrical connections within the device.

[0036] During use, it is advantageous to have a susceptor near the induction coil so that an alternating electromagnetic field reliably penetrates the open-porous induction heating ceramic material. Advantageously, the susceptor is arranged in the vicinity of the induction coil. Also, the distance between the induction coil and the susceptor is desirably substantially constant over the extent of the susceptor to ensure homogeneous heating. The minimum distance between the susceptor and the induction coil is preferably less than 2 mm, especially less than 1 mm, or less than 0.5 mm.

[0037] The aerosol generating device may comprise a device housing. The device housing may include a susceptor, an induction source, an induction coil, an AC generator, an electrical circuit, and a power source. As further described below, the device housing may further include a tank or a liquid holding element, or both, for storing the aerosol-forming liquid.

[0038] The device housing may further comprise a recess in which the susceptor can be at least partially disposed. The recess may have an inner surface. The induction coil can be disposed on or adjacent to the surface of the recess closest to the power source. The induction coil can have a shape that conforms to the inner surface of the recess. Alternatively, the induction coil may be within the recess. In particular, the recess may be an aerosol generation chamber.

[0039] The device housing may comprise a body and a mouthpiece portion. The recess can be within the body, and the mouthpiece portion can have an outlet through which the aerosol generated by the device can be drawn out. The induction coil can be disposed within the body, within the mouthpiece portion, or within both the body and the mouthpiece portion. As used herein, the term "mouthpiece portion" means a part of the device that is placed in the user's mouth for directly inhaling the aerosol generated by the aerosol generating system. The aerosol is conveyed to the user's mouth through the mouthpiece.

[0040] The device may comprise an air path extending from at least one air inlet to at least one air outlet. The air outlet is preferably the outlet of the mouthpiece. The air path passes through the outer surface of the susceptor, particularly an open porous ceramic material. The air path may pass through a recess. The air path may also pass through an induction coil. By enabling the air flow to pass through the coil through the device, a compact system can be achieved. The induction coil may be arranged adjacent to the susceptor. The air path may include an air flow path provided between the induction coil and the susceptor element. The vaporized aerosol-forming material can be entrained in the air flow within the air flow path, which then cools to form an aerosol, and the aerosol escapes through the air outlet.

[0041] The open porous ceramic material of the susceptor may be (pre-) impregnated with a predetermined amount of aerosol-forming liquid, for example, for single use of the device. However, multiple uses of the device and the susceptor incorporated therein may also be preferred. Thus, the device may be configured to repeatedly or continuously immerse the susceptor in the aerosol-forming liquid. For this purpose, the aerosol-generating device may further comprise a tank for holding or storing the aerosol-forming liquid. The tank may be replaceable or refillable. The tank may be arranged within the housing of the device, particularly within the body of the device. To (re-) immerse the susceptor with the aerosol-forming liquid, the tank is in fluid communication with the susceptor, for example, via a fluid channel or a fluid pipe.

[0042] The movement of the aerosol-forming liquid from the tank to the susceptor preferably occurs by gravity. Alternatively, the liquid movement may occur by capillary action, such as via a capillary wick element between the tank and the susceptor. The aerosol-generating device may also include a pumping device, such as a micropump, for moving the aerosol-forming liquid from the tank to the susceptor.

[0043] The aerosol generating device may be configured such that immersing the susceptor in the aerosol-forming liquid from the tank occurs only at a specific location of the device, for example, the vertical or overhead position of the device. As used herein, the position of the device primarily refers to the orientation of the device in space, particularly with respect to gravity. In other words, the aerosol generating device may be configured such that immersing the susceptor in the aerosol-forming liquid from the tank requires orienting the device in a specific position. The specific position may be referred to as the "immersion position". Advantageously, this reduces the risk of unwanted immersion or over-immersing the susceptor beyond its capacity.

[0044] The aerosol generating device may be configured such that the movement of the aerosol-forming liquid from the tank to the susceptor occurs only by gravity. For this purpose, the relative arrangement between the susceptor and the tank may be such that, at the specific immersion position of the device, the susceptor is arranged at a level lower than the level of the tank. In contrast, during operation of the device, i.e., during aerosol generation, the susceptor is preferably arranged at a level above the level of the tank. Thus, at the operating position, there is no movement of the aerosol-forming liquid from the tank to the susceptor. If there is movement, any excess aerosol-forming liquid may flow back from the susceptor or the fluid path / fluid pipe to the tank at the operating position.

[0045] As an alternative or in addition, the fluid communication between the susceptor and the tank can be blocked or released. In particular, the aerosol generating device can be configured such that the tank is in fluid communication with the susceptor only at a specific immersion position of the device. At least at the operating position of the device and at any position other than the immersion position, the fluid communication can be disabled, released, interrupted or stopped. To achieve a blockable or releasable fluid communication, the aerosol generating device can comprise a valve for controlling the fluid communication between the tank and the susceptor. The valve can be a gravity-actuated valve that opens only at a specific position of the device, such as the upper or lower position or the overhead position of the device. The valve can be a controllable solenoid valve. The solenoid valve can be manually controllable, for example, by a switch. As an alternative, the solenoid valve can be coupled to the electrical circuit of the aerosol generating device to control the closing and opening of the valve. The electrical circuit can further comprise a position sensor, such as a microchip package MEMS gyroscope, for determining the position of the aerosol generating device. Thus, the electrical circuit can be configured to open the solenoid valve only when it detects that the aerosol generating device is in a specific position. When the position sensor detects any other position, the valve is closed by the electrical circuit.

[0046] The aerosol generating device can be further configured such that heating of the susceptor is disabled while the susceptor is immersed in the aerosol-forming liquid. Advantageously, this prevents unintentional gas formation in the tank.

[0047] The aerosol generating device can be configured such that the aerosol passage leading to the aerosol output of the aerosol generating device is closed while the susceptor is immersed in the aerosol-forming liquid. Advantageously, this prevents unintentional absorption of the aerosol-forming liquid by the user of the device.

[0048] Due to the open porous structure of the ceramic material, the susceptor already provides a high liquid holding capacity. Nevertheless, the aerosol generating device may further comprise a liquid holding element for holding additional aerosol forming liquid. The liquid holding element may comprise a high holding material or a high release material (HRM) for storing the liquid aerosol forming substrate. Advantageously, the liquid holding element may be a storage medium for the aerosol forming liquid for immersing the susceptor. For this reason, it is preferred that the liquid holding element is in direct contact with the susceptor. Thus, the aerosol forming liquid stored within the liquid holding element can be easily transferred to the susceptor, for example, by capillary action. It is preferred that the aerosol forming liquid held within the liquid holding element is not available for atomization until it leaves the holding element. The liquid holding element may be non-conductive. The liquid holding element may also be paramagnetic or diamagnetic. It is preferred that the liquid holding element is non-inductively heated. The liquid holding element may be arranged in the aerosol generating device such that it is not affected or minimally affected by the alternating electromagnetic field of the induction coil.

[0049] The aerosol generating device may comprise both a liquid holding element and a tank for the aerosol forming liquid. The tank is preferably in fluid communication with the liquid holding element, which in turn may be in fluid communication with the susceptor. Thus, the liquid holding element is (re)filled from the tank and the susceptor is immersed from the liquid holding element.

[0050] As described above, the susceptor may be part of a consumable aerosol generating article that is pre-impregnated with an aerosol-forming liquid so as to be ready for use in an aerosol generating device including an induction source, or may be a consumable aerosol generating article. The aerosol generating article may be part of a cartridge for use in an aerosol generating device, or may be a cartridge. Accordingly, the present invention also provides a cartridge for use in an inductively heated aerosol generating device. The cartridge includes an aerosol-forming liquid and an inductive heating susceptor according to and as described herein. The susceptor comprises, is made of, or consists of, the open-porous inductive heating ceramic material described herein that holds at least a portion of the aerosol-forming liquid contained within the cartridge. In addition to holding at least a portion of the aerosol-forming liquid, the inductive heating ceramic material enables the aerosol-forming liquid held therein to be inductively heated under the influence of an alternating electromagnetic field.

[0051] The cartridge is a consumable, particularly a disposable aerosol generating article. It is configured to be received within a recess of the aerosol generating device, which in turn comprises an induction source for inductively heating the susceptor of the cartridge when received within the recess. During operation, the induction source generates an alternating electromagnetic field that penetrates the susceptor of the cartridge received within the recess. Depending on the electrical and magnetic properties of the inductive heating ceramic material, the alternating electromagnetic field causes at least one of eddy currents or hysteresis losses within the susceptor. As a result, the susceptor is heated and vaporizes the aerosol-forming liquid held therein. Due to the open-porous structure of the ceramic material, the vaporized aerosol-forming liquid can pass through the susceptor and then be cooled to form an aerosol.

[0052] The susceptor that holds the aerosol-forming liquid preferably consists essentially of a cartridge, i.e., a consumable aerosol-generating article. In this case, the susceptor can hold the entire aerosol-forming liquid of the cartridge. In other words, the cartridge according to the present invention may consist only of a susceptor immersed in the aerosol-forming liquid. Advantageously, such cartridges are simple, inexpensive and robust.

[0053] Furthermore, the cartridge may include a cartridge housing that at least partially surrounds the immersed susceptor. Preferably, the cartridge housing completely surrounds the susceptor, i.e., the susceptor can be within the cartridge housing.

[0054] When the cartridge housing is received in the recess of the aerosol-generating device, the housing is preferably non-conductive.

[0055] The susceptor may fill at least a portion of the internal space of the cartridge housing.

[0056] The cartridge housing may be at least partially or completely removable so as to at least partially or completely open the susceptor. During operation, this allows the vaporized aerosol-forming liquid to escape freely from the cartridge and vice versa, allowing air to enter the susceptor. In particular, when the cartridge constitutes a consumable aerosol-generating article consisting essentially of a susceptor immersed in the aerosol-forming liquid, the cartridge housing can be at least partially or completely removed before engaging the cartridge with the aerosol-generating device, i.e., before engaging the partially or completely open susceptor with the aerosol-generating device, and can serve as an envelope or cover for the susceptor.

[0057] The cartridge housing may include at least one fluid permeable portion. As used herein, "fluid permeable portion" refers to a portion of the cartridge housing that allows gases, preferably liquids as well, to penetrate therethrough. In particular, at least one fluid permeable portion of the cartridge housing may allow aerosol-forming liquid to penetrate therethrough in either the gas phase or both the gas phase and the liquid phase. The cartridge housing may have a plurality of fluid permeable portions. At least a portion of these portions of the cartridge housing that cover or contact the susceptor may be fluid permeable. The entire cartridge housing may be fluid permeable. The latter configuration is advantageous with respect to a cartridge that is completely filled with a susceptor immersed in aerosol-forming liquid or a cartridge that consists essentially of a susceptor immersed in aerosol-forming liquid.

[0058] Due to the high holding capacity of the susceptor material, the susceptor itself may also form at least a part of the cartridge housing. The susceptor may form the complete cartridge housing. As an example, the cartridge may be a hollow cylinder having a circumferential wall and two end walls. The circumferential wall and the end walls form the housing of the cartridge. At least one end wall or at least a portion of the circumferential wall, or both, may be formed by the susceptor.

[0059] The susceptor may only partially fill the volume of the cartridge housing. Advantageously, the internal void volume of the cartridge can be used as a tank or reservoir filled with the aerosol-forming liquid. A portion of the surface of the susceptor facing the interior of the cartridge may be in direct contact with the aerosol-forming liquid. Thus, the heated aerosol-forming liquid held within the susceptor is vaporized and released from the cartridge through the open porous structure of the ceramic susceptor material. At the same time, the susceptor is continuously refilled or re-dipped by the aerosol-forming liquid stored within the cartridge tank or reservoir. A cartridge having a void volume filled with the aerosol-forming liquid has a longer operating time compared to a cartridge in which the susceptor completely fills the cartridge volume. This is due to the liquid storage capacity of the susceptor volume being low compared to a free volume of equal size.

[0060] The entire surface corresponding to the outer contour of the susceptor body present on the outer surface of the cartridge can be about 25 mm 2 or so.

[0061] Further features and advantages of the cartridge according to the present invention are described above with respect to the susceptor and will not be repeated.

[0062] According to the present invention, there is also provided an aerosol generation system for generating an aerosol by inductively heating an aerosol-forming liquid. The system comprises an aerosol generation device and a cartridge according to the present invention and described herein. Accordingly, the cartridge comprises an aerosol-forming liquid and an inductive heating susceptor according to the present invention and described herein for holding at least a portion of the aerosol-forming liquid. The cartridge is configured to engage with the aerosol generation device so as to be used in the aerosol generation device, i.e., to generate an aerosol by inductively heating the aerosol-forming liquid contained within the cartridge. For this purpose, the aerosol generation device comprises a device housing including a recess for receiving at least a portion of the cartridge. The aerosol generation device further comprises an induction source within the device housing including an induction coil for generating an alternating electromagnetic field. The aerosol generation device and the cartridge are configured such that the susceptor is disposed relative to the induction coil so as to be inductively heatable by the alternating electromagnetic field when the cartridge is received within the recess.

[0063] The induction coil may be disposed on or adjacent to the inner surface of the recess. The induction coil may be shaped to conform to the inner surface of the recess. Alternatively, the induction coil may be within the recess. In some embodiments, the induction coil may be within the internal passage of the cartridge when the cartridge is engaged with the device.

[0064] The device housing may comprise a body and a mouthpiece portion. The recess may be within the body, and the mouthpiece portion may have an outlet through which the aerosol generated by the system is drawn. The induction coil may be within the mouthpiece portion or within the body. Alternatively, the mouthpiece portion may be provided as a part of the cartridge.

[0065] The device may comprise an air path extending from at least one air inlet to at least one air outlet. The air outlet is preferably the outlet of the mouthpiece. The air path passes through the susceptor, in particular the outer surface of an open porous ceramic material. The air path may pass through a recess. The air path may also pass through an induction coil. By enabling the air flow to pass through the coil through the device, a compact system can be achieved. In use, the induction coil may be arranged adjacent to the susceptor when the cartridge is engaged with the device, i.e., when received within the recess. The air path may include an air flow path provided between the induction coil and the susceptor element when the cartridge is received within the recess. The vaporized aerosol-forming material can be entrained in the air flow within the air flow path, which then cools to form an aerosol, and the aerosol can escape through the air outlet.

[0066] Compared with the aerosol generating device described above, the aerosol generating device described herein does not comprise an internal reservoir for the aerosol-forming liquid such as an internal susceptor and a liquid tank. However, otherwise, the aerosol generating device described herein may be similar or identical to the aerosol generating device described above.

[0067] In particular, the induction source and the induction coil of the aerosol generating device described herein may be similar or identical to the induction source and the induction coil of the aerosol generating device described above. Similarly, the aerosol generating device described herein may also comprise at least one of an AC generator, an electrical circuit, and a power source as described above.

[0068] Further features and advantages of the aerosol generating device described herein, in particular the features and advantages of the induction source, the induction coil, the AC generator, the electrical circuit, and the power source, have been described with respect to the aerosol generating device described above and will not be repeated. The present invention will be further described by way of illustration only with reference to the accompanying drawings.

Brief Description of the Drawings

[0069]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

DETAILED DESCRIPTION OF THE INVENTION

[0070] FIG. 1 is a schematic view of an aerosol generating system 1 according to a first embodiment of the present invention. The system comprises an aerosol generating device 100 and a cartridge 200 for engaging with the aerosol generating device 100. The device body 100 comprises a main body having a main body housing 101 containing a lithium-ion battery as a power source 102, and a control electronic circuit 104. The main body housing 101 defines a recess 112 therein for receiving the cartridge 200. The device 100 also includes a mouthpiece portion 120 including an outlet 124. The housing of the mouthpiece portion 120 and the main body housing 101 together form the housing of the device 100. The mouthpiece portion can be connected to the main body by any type of connection, such as a hinged connection, a snap-on attachment or a screw attachment. An air inlet 122 is defined within the main body housing 101.

[0071] A flat spiral induction coil 110 is disposed within the recess 112. The coil 110 is operatively connected to the control electrical circuit 104. The coil 110 is also illustrated in FIG. 2. The coil 110 is formed by stamping or cutting a spiral coil from a copper plate. The coil 110 is disposed proximate to the inner surface of the recess 112 opposite the end face of the cartridge 200 at the level of the air inlet 122. Thus, the air drawn through the inlet 122 towards the outlet 124 passes through the passage formed between the coil 112 and the end face of the cylindrical cartridge 200. Advantageously, the flat spiral coil allows for a simple interface between the device and the cartridge, enabling a simple and inexpensive cartridge design.

[0072] In this embodiment, the cartridge 200 is of a circular cylindrical shape. The cylindrical cartridge 200 includes a cartridge housing 204 containing an aerosol-forming liquid 202. The aerosol-forming liquid can be retained by a capillary material. The cartridge housing 204 is fluid-impermeable but has an open end covered by a susceptor 210. Further details of the cartridge 200 are illustrated in FIGS. 4 and 5. In this embodiment, the susceptor 210 is a compact solid susceptor body made of an open-porous ferromagnetic ceramic material, for example, Ni 0.5 Zn 0.5 Fe2O4. The susceptor body 210 is of a cylindrical shape and is inserted into the open end of the cartridge housing 204. Thus, the susceptor 210 forms at least a part of the cartridge housing 204. The cylindrical susceptor body 210 has an axial length of 3 mm to 6 mm, preferably having an axial length of 4 to 5 mm. The entire surface corresponding to the outer cylindrical contour of the susceptor body 21 can be about 25 mm 2 or so.

[0073] The inner end surface of the cylindrical susceptor body 210 faces the inside of the cartridge housing 204 so as to be in direct contact with the aerosol-forming liquid 202 contained within the cartridge 200. Due to the open-porous structure of the ceramic material, the susceptor is immersed in the aerosol-forming liquid 202. Accordingly, the susceptor 210 retains at least a part of the aerosol-forming liquid 202 contained within the cartridge 200. The outer end surface of the cylindrical susceptor body 210 forms the outer surface of the cartridge 200. Thus, there may be a case where the heated aerosol-forming liquid held within the susceptor is vaporized and freely escapes from the cartridge 200 through the outer end surface of the open-porous susceptor body 210.

[0074] The open porous structure is such as to provide a high holding capacity for the liquid aerosol forming material. Thus, the aerosol forming liquid is safely maintained or held within the susceptor 210. Advantageously, this enables the cartridge 200 to be leak-proof with respect to the aerosol forming liquid 202 contained therein even if a part of the cartridge housing is made of an open porous material. Conversely, the open porosity of the susceptor material is such as to allow the aerosol forming material vaporized upon heating to be freely released from the cartridge.

[0075] When the cartridge 200 engages with the aerosol generating device 100 and is received within the recess 112, the susceptor element 210 is disposed adjacent to the flat spiral coil 110. The cartridge 200 may include keyed features to ensure that it cannot be inserted upside down into the device.

[0076] In use, the user inhales through the mouthpiece portion 120, drawing air through the air inlet 122 into the recess 112 and the mouthpiece portion 120 and out of the outlet 124 into the user's mouth. The device may include a smoking sensor 106 in the form of a microphone for detecting when the user is smoking on the mouthpiece. The smoking sensor 106 may be part of the control electrical circuit 104. The smoking sensor 106 may be disposed within the recess near the air inlet 122. When smoking is detected, the electrical circuit 104 supplies a high-frequency oscillating current to the coil 110. This generates an oscillating magnetic field that passes through the susceptor 210. As a result, the susceptor 210 is heated by hysteresis losses to a temperature sufficient to vaporize the aerosol forming liquid held within the open pores of the susceptor material. The vaporized aerosol forming material is mixed with the air flowing from the air inlet 122 towards the air outlet 124. In this process, the vapor is cooled to form an aerosol within the mouthpiece portion 120 and then escapes through the outlet 124. The control electronic circuit 104 supplies an oscillating current to the coil 110 for a predetermined duration (5 seconds in this example) when an inhalation is detected, after which the current is turned off until a new inhalation is detected.

[0077] Figure 3 is a schematic view of an aerosol generation system 1 according to a second embodiment of the present invention. The system 1 includes an aerosol generator 100 and a cartridge 200. Except for the induction coil, this second embodiment is the same as the first embodiment shown in FIG. 1. Therefore, in both embodiments, the same features of the aerosol generator and the cartridge are denoted by the same reference numerals. Instead of the flat spiral induction coil, the aerosol generator 100 according to the second embodiment includes a helical induction coil 170 disposed within the recess 112 such that when the cartridge is received within the recess 112, the susceptor 210 is disposed within the helical induction 170. By applying a high-frequency oscillating current to the coil 170, a substantially homogeneous oscillating magnetic field is generated within the helical coil 170. Thus, when the cartridge 200 engages the aerosol generator 100, the susceptor 120 is uniformly affected by the oscillating magnetic field, which is advantageous with respect to the uniform heating of the susceptor. Alternatively, the helical induction 170 may also be disposed on the inner surface of the recess 112 or within the wall of the body housing 101, which allows for a simple and compact design of the aerosol generator 100.

[0078] The cartridge 200 according to the embodiments shown in FIGS. 1-5 has a simple and robust design that can be manufactured at a lower cost compared to commercially available cartomisers. However, as shown in FIGS. 6-16, other configurations are possible.

[0079] 6 and 7 show schematic diagrams of an alternative cartridge design having a hollow cylindrical shape. The susceptor 210 is a compact susceptor body made of an open-porous ferrimagnetic ceramic material that forms a peripheral portion of the circumferential wall of the cartridge housing 204. Thus, the susceptor 220 is tubular in shape. The interior of the hollow cartridge 200 contains an aerosol-forming liquid, a portion of which is held within the susceptor 210. The cartridge shown in FIGS. 6 and 7 can be designed to engage with an aerosol generator comprising a helical induction coil as shown in FIG. 3. The aerosol generator is preferably designed such that when the cartridge engages with the aerosol generator, the susceptor is coaxially positioned within the interior of the helical coil. Thus, the heating of the susceptor is advantageously very homogeneous. Furthermore, the active heating volume of the cartridge design shown in FIGS. 6 and 7 is larger compared to the cartridge design shown in FIGS. 4 and 5, leading to a more intense user experience.

[0080] FIG. 8 shows a schematic cross-sectional view of another cartridge design in which the cartridge is completely filled by the susceptor 210. In this embodiment, the susceptor 210 is a compact susceptor body made of an open-porous ferrimagnetic ceramic material that provides high retention to the liquid aerosol-forming substrate. Thus, the cartridge 200 of this embodiment advantageously reduces the risk of spillage, for example, compared to a liquid tank. In case of cartridge crack failure, the high retention material of the susceptor avoids unintended contact of the aerosol-forming liquid and the active electrical components of the device with biological tissue.

[0081] The cartridge 200 comprises a cartridge housing 204 that at least partially surrounds a susceptor 210. During use, vaporized aerosol-forming substrate may escape the cartridge through those portions of the susceptor that are not covered by the cartridge housing.

[0082] The cartridge housing 204 may also completely surround the susceptor 210. In this case, at least a portion of the cartridge housing 204 may be fluid permeable to allow the vaporized aerosol-forming substrate to escape from the cartridge. The complete cartridge housing 204 is preferably fluid permeable as shown in FIG. 9. Advantageously, this allows for the best user experience.

[0083] Alternatively, the susceptor 210 may be contained within an impermeable cartridge housing 204 that completely surrounds the susceptor 210, as shown in FIG. 10. Advantageously, this prevents the immersed susceptor from drying out. As shown in FIG. 11, at least a portion of the cartridge housing 204 may be removable or openable before engaging the cartridge with the aerosol generating device, i.e., before engaging the partially or fully open susceptor with the aerosol generating device. In the embodiment of FIG. 11, the cartridge housing 204 may be removable at the end face. Removing the end face portion of the cartridge housing 204 allows the partially open cartridge to engage with the aerosol generating device. During operation, the vaporized aerosol-forming substrate may escape from the cartridge through the open end face.

[0084] Similarly, the cartridge design according to FIGS. 4 and 5 or FIGS. 6 and 7 may include a cartridge housing 204 that also covers the outer surface of the susceptor 210. A portion of the cartridge housing 204 that covers the susceptor is removed or opened before engaging the cartridge with the aerosol generating device. The removable or openable portion of the cartridge housing may be considered a protective cover for the susceptor. The outer surface susceptor may be flush with the outer surface of the remaining portion of the cartridge housing, or may be recessed such that the outer surface of the cartridge housing is smooth.

[0085] Figures 12 and 13 schematically illustrate another cartridge design where the complete cartridge housing 204 is a protective cover or a packing sleeve that is removed before the remainder of the cartridge engages with the aerosol generating device. Such a cover or sleeve may be advantageous with respect to a cartridge that consists essentially of a compact susceptor body (see Figure 12) or a cartridge with a closed surface or a hollow susceptor body that encloses the aerosol-forming liquid (see Figure 13). In both embodiments, the susceptor body essentially constitutes a consumable aerosol-generating article that engages with the aerosol generating device upon removal of the packing sleeve 204 that surrounds the article. As shown in Figures 12 and 13, the surrounding packing sleeve 204 may be open at the end faces to allow removal of the susceptor body. With respect to the susceptor design shown in Figure 13, the closed susceptor surface may be regarded as the remaining housing for these cartridge parts that engage with the aerosol generating device.

[0086] Instead of a single-piece susceptor body, the susceptor may comprise a plurality of susceptor elements 211. As illustrated in Figure 14, the susceptor elements may be individual susceptor pellets 211 that are impregnated with an aerosol-forming liquid to form susceptor fines. The susceptor elements 211 may be contained within the cartridge housing 204, at least a portion of which is fluid permeable. For example, the cartridge housing or a portion of the complete cartridge housing may be of a mesh-like configuration and may be made of, for example, stainless steel mesh. In Figure 14, the complete cartridge housing 204 is fluid permeable. Advantageously, such a cartridge housing 204 holds the individual susceptor elements together while allowing the vaporized aerosol-forming substrate to escape from the cartridge.

[0087] Alternatively, as shown in FIG. 15, the susceptor element 211 may be contained within an impermeable cartridge housing 204. Advantageously, this prevents the immersed pellets from drying. As illustrated in FIG. 16, at least a portion of the cartridge housing may be removable or openable such that an individual susceptor element (see FIG. 17) that can subsequently be filled into the recess of the aerosol generating device can be removed. When the individual susceptor elements are received into the aerosol generating device as a bulk material without a cartridge housing, i.e., as a loose commodity, the aerosol generating device may comprise a container for receiving the susceptor elements into the recess and holding the susceptor elements securely. At least a portion of the container may be fluid permeable to allow the vaporized aerosol forming substrate to escape from the container. The container may comprise a filling port. The filling port may be closable, for example, by a lid or by the mouthpiece of the aerosol generating device.

[0088] Figure 18 schematically illustrates a first embodiment of an aerosol generating device 100 according to another aspect of the present invention. Instead of being engagable with a separate cartridge containing a susceptor to be heated and an aerosol-forming liquid, the aerosol generating device 100 itself comprises a susceptor 180 according to and as described herein in the present invention, which is an internal susceptor made of an open porous ferromagnetic ceramic material. Similar to the aerosol generating devices shown in Figures 1 and 3, the device 100 according to Figure 13 comprises a body having a body housing 101 that includes a battery 102 and a control electrical circuit 104. The body housing 101 defines a recess 112 within which the internal susceptor 180 is disposed. The device 100 also includes a mouthpiece portion 120 that includes an outlet 124. The housing of the mouthpiece portion 120 and the body housing 101 together form the housing of the device 100. The mouthpiece portion is removably connected to the body. An air inlet 122 is defined within the body housing. Within the recess 112 is a helical induction coil 170. The coil 170 is operably connected to the control electrical circuit 104 and surrounds the cylindrical susceptor body 180. When the electrical circuit 104 supplies a high-frequency oscillating current to the coil 170, an oscillating magnetic field is generated that passes through the susceptor 180. As a result, the susceptor 180 is heated by hysteresis losses, causing vaporization of the aerosol-forming liquid retained within the open porous structure of the susceptor 180. The vaporized aerosol-forming material is entrained in the air flow created when the user draws air through the air inlet 122, into the recess 112 and the mouthpiece portion 120, and out of the outlet 124.

[0089] In this embodiment, the axial length extension of the helical coil 170 essentially corresponds to the axial length extension of the cylindrical susceptor 180. Of course, the coil 170 may also be configured to surround only the axial portion of the susceptor 180. Advantageously, the amount of aerosol-forming liquid to be heated and vaporized can be preset using the degree of overlap between the coil and the susceptor 180 in order to optimize the user experience.

[0090] To repeatedly (re)fill the susceptor 180 with the aerosol-forming liquid, the aerosol-generating device 100 further comprises a tank 185 for the aerosol-forming liquid. The tank may be replaceable or refillable. The tank 185 is arranged within the main housing 101 of the device 100. The tank 185 is in fluid communication with the susceptor 180 via a fluid channel 186. A controllable valve 187 is arranged together with the fluid channel 186. The valve 187 is operably coupled to the electrical circuit 104 to control the stopping and opening of the valve. The aerosol-generating device 100 is configured to open the valve 186 only in the upright or overhead position of the device. Thus, immersing the susceptor 180 with the aerosol-forming liquid from the tank 185 requires orienting the device 100 in this specific “immersion” position. Advantageously, this reduces the risk of unnecessary immersion and over-immersing the susceptor 180 beyond its capacity. The movement of the aerosol-forming liquid from the tank 185 to the susceptor 180 preferably occurs by gravity. To detect the respective positions of the device, the device 100 may comprise a position sensor (not shown) as part of the electrical circuit 104. Further, the electrical circuit 104 may be configured to deactivate the heating process in the “immersion” position to prevent unintentional gas formation. Further, the electrical circuit 104 may be configured to block the air path towards the outlet 124 during the (re)filling of the susceptor 180 to prevent unintentional absorption of the aerosol-forming liquid by the user. For this purpose, the device 100 may comprise a shutter (not shown). The device 100 may also be configured to allow heating of the susceptor 180 only in one or more predetermined “use” positions.

[0091] FIG. 19 schematically illustrates a second embodiment of an aerosol generating device 100 comprising an internal susceptor 180. This embodiment is essentially the same as the embodiment shown in FIG. 18. Accordingly, in both embodiments, the same features of the aerosol generating device are denoted by the same reference numerals. Further, the device 100 according to FIG. 19 comprises a liquid holding element 190 made of a high retention material or high release material (HRM). The liquid holding element 190 functions as a storage medium for the aerosol forming liquid for continuously immersing the susceptor 180. For this reason, the liquid holding element 190 is in direct contact with the susceptor 180. The aerosol forming liquid stored in the liquid holding element 190 is moved to the susceptor 180 by capillary action. The liquid holding element 190 is non-conductive and paramagnetic and is thus non-inductive heating. For this reason, the induction coil 170 surrounds only the susceptor 180. The liquid holding element is in fluid communication with the tank 185 via the fluid channel 186 and is filled with the aerosol forming liquid from the tank 185. Further advantages of the embodiment shown in FIG. 19 have been described with respect to the embodiment shown in FIG. 18 and will not be repeated.

[0092] 1. An induction heating susceptor for use in an aerosol generating device or system, wherein the susceptor is made of an open-porous induction heating ceramic material for holding an aerosol forming liquid and heating the aerosol forming liquid under the influence of an alternating electromagnetic field, the susceptor comprising a compact solid body or a plurality of susceptor elements, each susceptor element being a compact solid body comprising the open-porous induction heating ceramic material. 2. The susceptor according to 1, wherein the open-porous induction heating ceramic material comprises - manganese magnesium ferrite, - nickel zinc ferrite, or - cobalt zinc barium ferrite, or consists of at least one of them. 3. The susceptor according to either 1 or 2, wherein the open-porous induction heating ceramic material has a porosity of 20% to 60%. 4. The susceptor according to any one of 1 to 3, wherein the open porous induction heating ceramic material has a Curie temperature of 150°C to 400°C. 5. The susceptor according to any one of 1 to 4, wherein the open porous induction heating ceramic material is a non-conductive material. 6. The susceptor according to any one of 1 to 5, further comprising an aerosol-forming liquid held within the open porous induction heating ceramic material. 7. An aerosol generator for generating an aerosol by inductively heating an aerosol-forming liquid, the apparatus comprising: - an induction source including an induction coil for generating an alternating electromagnetic field; - a susceptor according to any one of 1 to 6 for holding and heating the aerosol-forming liquid, the susceptor being arranged relative to the induction coil so as to be inductively heated by the alternating electromagnetic field. 8. The aerosol generator according to 7, further comprising a replaceable or refillable tank for holding the aerosol-forming liquid, the tank being releasably in fluid communication with the susceptor for immersing the susceptor in the aerosol-forming liquid. 9. The aerosol generator according to either 7 or 8, further comprising a liquid holding element for holding the aerosol-forming liquid, the liquid holding element being in direct contact with the susceptor. 10. A cartridge for use in an aerosol generator, the cartridge comprising an aerosol-forming liquid and an induction heating susceptor according to any one of 1 to 6 for heating the aerosol-forming liquid, the susceptor holding at least a portion of the aerosol-forming liquid. 11. The cartridge according to 10, wherein the cartridge comprises a cartridge housing surrounding the susceptor, the cartridge housing being at least partially removable or comprising at least one fluid-permeable portion. 12. The cartridge according to claim 10, wherein the cartridge comprises a cartridge housing, and the susceptor forms at least a part of the cartridge housing. 13. An aerosol generation system for generating an aerosol by inductively heating an aerosol-forming liquid, the system comprising an aerosol generator and a cartridge according to any one of claims 10 to 12 for use in the aerosol generator, the aerosol generator comprising a device housing including a recess for receiving at least a part of the cartridge, an induction source within the device housing including an induction coil for generating an alternating electromagnetic field, an aerosol generation system, wherein the susceptor of the cartridge is arranged within the recess relative to the induction coil such that the susceptor is inductively heated by the alternating electromagnetic field.

Claims

1. A cartridge for use in an aerosol generating device or system, said cartridge comprising an inductive heating susceptor, said susceptor comprising an open-porous inductive heating ceramic material for holding an aerosol-forming liquid and heating said aerosol-forming liquid under the influence of an alternating electromagnetic field, said susceptor being a single body or said susceptor comprising a plurality of susceptor elements, each susceptor element being a single body comprising said open-porous inductive heating ceramic material, said open-porous inductive heating ceramic material being inductively heatable by at least one of hysteresis losses or eddy currents within said open-porous inductive heating ceramic material.

2. said open-porous inductive heating ceramic material being - manganese magnesium ferrite, - nickel zinc ferrite, or - cobalt zinc barium ferrite, and comprising at least one of or consisting of the cartridge according to claim 1.

3. said open-porous inductive heating ceramic material having a porosity of 20% to 60%, the cartridge according to claim 1 or 2.

4. said open-porous inductive heating ceramic material having a Curie temperature of 150 ° C to 400 ° C, the cartridge according to any one of claims 1 to 3.

5. said open-porous inductive heating ceramic material being a non-conductive material, the cartridge according to any one of claims 1 to 4.

6. further comprising an aerosol-forming liquid held in said open-porous inductive heating ceramic material, the cartridge according to any one of claims 1 to 5.

7. The cartridge according to any one of claims 1 to 6, wherein the cartridge includes a cartridge housing surrounding the susceptor, and the cartridge housing is at least partially removable or includes at least one fluid-permeable part.

8. The cartridge according to claim 7, wherein the cartridge includes a cartridge housing, and the susceptor forms at least a part of the cartridge housing.

9. The cartridge according to claim 8, wherein the susceptor only partially fills the volume of the cartridge housing.

10. The cartridge according to any one of claims 1 to 9, wherein the susceptor is immersed in the aerosol-forming liquid.

11. An aerosol generation system for generating an aerosol by inductively heating an aerosol-forming liquid, the system comprising an aerosol generator and a cartridge according to any one of claims 1 to 10 used in the aerosol generator, the aerosol generator comprising a device housing including a recess for receiving at least a part of the cartridge, an induction source including an induction coil for generating an alternating electromagnetic field, An aerosol generation system, wherein the susceptor of the cartridge is arranged relative to the induction coil so as to be inductively heated by the alternating electromagnetic field.

12. The aerosol generation system according to claim 11, wherein the device further includes a replaceable or refillable tank for holding the aerosol-forming liquid, and the tank is releasably in fluid communication with the susceptor for immersing the susceptor in the aerosol-forming liquid.

13. The aerosol generation system according to claim 11 or 12, wherein the device further comprises a liquid holding element for holding an aerosol-forming liquid, and the liquid holding element is in direct contact with the susceptor.

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