Aerosol-generating article for use with an induction-heated aerosol generator

Abstract

The present disclosure relates to an aerosol-generating article (100) for use with an inductively heated aerosol generator (10). The article comprises an aerosol-forming substrate (130) and a susceptor arrangement (120) for heating the aerosol-forming substrate through interaction of the susceptor arrangement with an alternating magnetic field provided by the aerosol-generating device. The susceptor arrangement comprises a plurality of elongated susceptor elements (121) comprised of a susceptor material dispersed throughout the aerosol-forming substrate. The elongated susceptor elements are aligned within the aerosol-forming substrate such that an angle between the length dimension of the elongated susceptor elements and a predetermined reference axis of the article, specifically the length axis of the article, is within a range of +30 degrees to -30 degrees. The present disclosure further relates to an aerosol-generating system comprising such an article and an inductively heated aerosol generator for use with the article.

Description

[Technical Field]

[0001] The present disclosure relates to aerosol-generating articles for use with inductively heated aerosol generators. The present disclosure also relates to aerosol-generating systems that include such articles and inductively heated aerosol generators for use with the articles. [Background technology]

[0002] Aerosol generating systems that use induction heating to generate inhalable aerosols are generally known in the prior art. These systems comprise an induction-heating aerosol generating device and a separate aerosol-generating article for use with the device. The article may include, among other components, an aerosol-forming substrate capable of forming an inhalable aerosol when heated, and an induction-heatable susceptor arrangement in thermal proximity or direct physical contact with the substrate to heat it. Induction heating of the susceptor arrangement is achieved by interaction of the susceptor arrangement with an alternating magnetic field provided by the aerosol generating device. During operation, the alternating magnetic field induces at least one of heat-generating eddy currents or hysteresis losses in the susceptor arrangement, causing it to heat to a temperature sufficient to release volatile compounds from the heated substrate, which can then be cooled to form an aerosol.

[0003] Different configurations of susceptor element-susceptor arrangements are known, depending on the type of substrate and the shape of the article. As an example, an article may include a single solid susceptor element, such as a susceptor strip, embedded within a solid or gel-like aerosol-forming substrate within the substrate portion of the article. While low-cost and readily available, solid susceptor elements create a single central heat source that can result in non-uniform temperature distribution across the substrate portion. This is because direct heating of the substrate occurs only in the immediate vicinity of the susceptor element, while the peripheral region of the substrate portion is heated only indirectly by heat conduction across adjacent substrate layers. In particular, high temperature gradients can overheat the internal region of the substrate portion near the susceptor element, while the temperature of the peripheral region of the substrate portion may be too low to volatilize the substrate. Furthermore, the heating efficiency of this configuration is highly sensitive to the proper positioning of the susceptor element within the substrate. All of this can result in suboptimal utilization of the aerosol-forming substrate. Alternatively, articles have been proposed that include spherical or quasi-spherical susceptor particles that are uniformly intercepted throughout the aerosol-forming substrate. While this leads to more uniform heating of the substrate, the heating efficiency of this susceptor configuration is limited, which can also affect extraction efficiency.

[0004] It would therefore be desirable to have inductively heatable aerosol-generating articles and aerosol-generating systems including such articles that have the advantages of prior art solutions but mitigate their limitations, and in particular, it would be desirable to have inductively heatable aerosol-generating articles and aerosol-generating systems including such articles that provide more efficient heating and utilization of the aerosol-forming substrate. Summary of the Invention

[0005] According to one aspect of the present invention, an aerosol-generating article for use in an induction-heated aerosol-generating device is provided. The article comprises an aerosol-forming substrate and a susceptor arrangement for heating the aerosol-forming substrate by interaction of the susceptor arrangement with an alternating magnetic field provided by the aerosol-generating device. The susceptor arrangement comprises a plurality of elongated susceptor elements, including or consisting of a susceptor material, dispersed throughout the aerosol-forming substrate. The elongated susceptor elements are aligned within the aerosol-forming substrate such that an angle between a length dimension of the elongated susceptor element and a predetermined reference axis of the article, particularly the length axis of the article, is in the range of +30 degrees to -30 degrees. In particular, the elongated susceptor elements are any one of fiber elements, wire elements, thread elements, particle elements, and rod elements. The fiber elements may be chopped fiber elements or milled fiber elements.

[0006] As used herein, the term "elongated susceptor element" refers to a susceptor element having a greater extent in one major dimension than in the two remaining dimensions perpendicular to the major dimension. Thus, an elongated susceptor element may be referred to as a 1D elongated susceptor element (synonymous with a one-dimensionally elongated susceptor element) or a quasi-1D susceptor element (synonymous with a quasi-one-dimensional susceptor element). Specifically, the term "elongated susceptor element" may refer to a susceptor element having a length dimension that is greater than any transverse dimension perpendicular to the length dimension. More specifically, a 1D elongated susceptor element may be an elongated susceptor element or a prolate susceptor element.

[0007] Compared to a single solid susceptor element, the use of multiple elongated susceptor elements dispersed throughout the aerosol-forming substrate advantageously results in a more uniform heat distribution across the substrate without significant temperature gradients across different substrate regions. Furthermore, if the susceptor material of the susceptor elements has high thermal conductivity, the uniformity of heat distribution is further enhanced by the fact that a substrate including multiple susceptor elements dispersed therein exhibits an equivalent increase in thermal conductivity compared to a substrate having no susceptor elements or only a single solid susceptor element. Furthermore, in achieving uniform heat distribution, the proposed susceptor arrangement is less sensitive to the positioning of the susceptor elements compared to a single solid susceptor element.

[0008] Most importantly, it has been found that the geometry, specifically the relative dimensions of the susceptor elements, has a significant impact on the substrate heating efficiency and, therefore, extraction efficiency. In this regard, it has been found that elongated susceptor elements are less prone to the demagnetizing effect than more uniformly sized susceptor elements, such as spherical or quasi-spherical susceptor particles. This can be explained as follows: When a susceptor element is placed in an external magnetic field, it is progressively magnetized. As the external magnetic field increases, the internal magnetization also increases. This process continues until the magnetization reaches the magnetic saturation point of the material, beyond which further magnetization cannot occur. As a result, the magnetization of the susceptor element causes a buildup of magnetic charge density at both ends of the susceptor element, as seen in the direction of the external magnetic field. As a result, the susceptor element generates a magnetic field that causes self-interaction with the material. This magnetic field is called the demagnetizing field because it is oriented in the same direction as the external magnetic field but opposite to it. The demagnetizing field depends on the geometry of the susceptor element but not on its absolute dimensions. When a susceptor element responds to a change in an external magnetic field, the demagnetizing field is generally assumed to be proportional to the magnetization in each direction, which is associated with a geometrically dependent proportionality constant known as the demagnetizing factor. The demagnetizing factor depends on the shape of the susceptor element as well as its relative orientation with respect to the external magnetic field. To this extent, it has been found that an external magnetic field passing through an elongated susceptor element, such as a susceptor element having the shape of a fiber or thin rod, whose length dimension is significantly greater than either of its transverse dimensions perpendicular to the length dimension, generates a weak or negligible demagnetizing field compared to a non-elongated (equidistant) susceptor element, such as a spherical or quasi-spherical susceptor element. This is intuitively understandable because in properly aligned elongated susceptor elements, the accumulated magnetic charge densities at both ends of the susceptor element are spatially separated from each other. This causes the demagnetizing field to have a significantly reduced strength and therefore less influence on the magnetizing field, which is the cause of power loss. As a result, power loss and therefore heating efficiency is greater in elongated susceptor elements compared to non-elongated (isometric) susceptor elements, such as spherical or quasi-spherical susceptor elements.This is particularly true when the magnetic field orientation is substantially parallel to the length of the elongated susceptor elements, which maximizes heating performance. However, it has been found that the elongated susceptor elements do not necessarily need to be perfectly parallel to the external magnetic field direction. Even when the susceptor elements are arranged at a certain range of angles relative to the external magnetic field orientation, the overall heating performance remains higher than that of a susceptor arrangement in which the susceptor elements are randomly oriented. Thus, it has been found that when the elongated susceptor elements are aligned within an aerosol-forming substrate such that the angle between the length of the elongated susceptor elements and a predetermined reference axis of the article is in the range of +30 degrees to -30 degrees, the heating efficiency of the substrate, and therefore the extraction efficiency, is still significantly increased. Preferably, the predetermined reference axis of the article is provided by the orientation of an alternating magnetic field provided by an aerosol-generating device used with the article. More specifically, the predetermined reference axis of the article may be defined by, i.e., correspond to, or be parallel to, the orientation of magnetic field lines at the location of the elongated susceptor elements when the aerosol-generating article is engaged with the device. For example, if, in use, the magnetic field lines at the location of the elongated susceptor elements within the article extend substantially parallel to the length axis of the article, the predetermined reference axis of the article may correspond to the length axis of the article. Thus, the elongated susceptor elements may be aligned within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor elements and the length axis of the article is within a range of +30 degrees to -30 degrees.

[0009] Overall, the high available power, the increased thermal conductivity of the substrate, and the homogeneous heat distribution within the substrate allow for rapid heating of the aerosol-forming substrate. Advantageously, heating times may be less than 0.5 milliseconds. The reduced heating times and low thermal gradients across the substrate even make it possible to achieve on-demand smoking, based on low or no power being supplied to the substrate during the standby dwell time, and instantaneous or near-instantaneous power delivery to heat the substrate and generate an aerosol only when the user requests it.

[0010] Since the overall heating performance of the elongated susceptor elements increases as the deviation from a substantially parallel alignment to the alternating magnetic field used for induction heating decreases, the elongated susceptor elements may preferably be positioned within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor elements and a predetermined reference axis of the article, in particular the length axis of the article, is in the range of +25 degrees to -25 degrees, in particular in the range of +10 degrees to -10 degrees.

[0011] As mentioned above, heating performance is maximized in the case of substantially parallel alignment. Therefore, the elongated susceptor elements are preferably aligned within the aerosol-forming substrate substantially parallel to a predetermined reference axis of the article, specifically the length axis of the article. As used herein, the term "substantially parallel" is understood as "a deviation of ±5° from parallel arrangement."

[0012] In general, the elongated susceptor elements may be randomly arranged within the aerosol-forming substrate, but the random arrangement will result in a reduced overall heating performance compared to a collection of elongated susceptor elements aligned within a specific angular range or arranged substantially parallel to the alternating magnetic field, since when considering a collection of susceptor elements, the overall heating performance of a collection of randomly oriented elongated susceptor elements will still be higher, on statistical average, than the heating performance of a collection of non-elongated susceptor elements.

[0013] In the present disclosure, whenever a number or range is given for a plurality of objects, such as a plurality of susceptor elements, this means that the number or range applies to at least 60 percent of all objects of the plurality, specifically at least 70 percent, more specifically at least 80 percent, and particularly at least 90 percent, and preferably applies to all objects of the plurality. For example, when the present disclosure states that elongated susceptor elements are aligned within an aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor element and the predetermined reference axis of the article is within a range of +A degrees to −A degrees, this means that at least 60 percent, specifically at least 70 percent, more specifically at least 80 percent, and particularly at least 90 percent of the elongated susceptor elements of the susceptor arrangement are arranged within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor element and the predetermined reference axis of the article is within a range of +A degrees to −A degrees.

[0014] The heating efficiency of the substrate, and therefore the extraction efficiency, is particularly improved when the ratio of the maximum length dimension of the elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the (maximum) length dimension is greater than 4, in particular greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35. In this specification, the ratio of the maximum length dimension of the elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the length dimension is also referred to as the shape factor or aspect ratio. Therefore, the shape factor of the elongated susceptor element is greater than 4, in particular greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35.

[0015] Preferably, the ratio of the maximum length dimension to the maximum transverse dimension (geometry factor) has not only a lower limit but also an upper limit. Thus, the ratio of the maximum length dimension of an elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the (maximum) length dimension, i.e., the geometry factor of the elongated susceptor element, can be in the range of 4 to 500, specifically 10 to 300, preferably 20 to 200, and more preferably 30 to 100.

[0016] In absolute terms, the maximum length dimension of the elongated susceptor elements may be in the range of 0.02 micrometers to 50 millimeters, particularly 1 micrometer to 16 millimeters, and preferably 0.1 millimeters to 5 millimeters, which is advantageous for dispersing the susceptor elements throughout the aerosol-forming substrate.

[0017] Depending on the absolute value of each of the maximum length dimensions, the absolute value of each of the maximum transverse dimensions of the elongated susceptor elements is preferably selected so that the geometry factor exceeds the lower limit defined above and advantageously falls within the preferred range defined above. Thus, the maximum transverse dimension of the elongated susceptor elements may be 500 micrometers, in particular 100 micrometers, preferably 10 micrometers, and more preferably 1 micrometer or less. Similarly, the maximum transverse dimension of the elongated susceptor elements may be in the range of 0.005 micrometers to 500 micrometers, in particular 0.1 micrometers to 150 micrometers, and preferably 20 micrometers to 100 micrometers. By way of example, the elongated susceptor elements may have a length dimension of approximately 2 millimeters and a transverse dimension of approximately 25 micrometers.

[0018] The heating efficiency also depends on the density of the elongated susceptor elements within the aerosol-forming substrate. The higher the density, the greater the heating efficiency. The (volume) density of the elongated susceptor elements within the aerosol-forming substrate is preferably within the range of 0.001 susceptor elements per cubic millimeter to 30 susceptor elements per cubic millimeter, specifically 0.1 susceptor elements per cubic millimeter to 10 susceptor elements per cubic millimeter. Similarly, the mass density of the elongated susceptor elements within the aerosol-forming substrate may be within the range of 0.002 milligrams of susceptor mass per cubic millimeter to 0.3 milligrams of susceptor mass per cubic millimeter, specifically 0.01 milligrams of susceptor mass per cubic millimeter to 0.1 milligrams of susceptor mass per cubic millimeter.

[0019] In general, the susceptor elements may have any elongated geometric shape. Specifically, the elongated susceptor elements may have one of an elongated cylindrical shape or an oblate ellipsoid shape. That is, the elongated susceptor elements may have a rod-like shape or a particle-like shape.

[0020] By way of example, the elongated susceptor elements may be fiber elements, in particular chopped or milled fiber elements. As another example, the elongated susceptor elements may be wire elements, or thread elements, or particle elements, or filament elements, or rod elements. Advantageously, the fiber elements, or wire elements, or thread elements, or particle elements, or filament elements, or rod elements are made of an inductively heatable material, such as metal fiber, or metal wire, or metal thread, which is readily available at low cost.

[0021] As viewed in a plane perpendicular to the length dimension of the elongated susceptor element, the cross section of the elongated susceptor element may have a circular, oval, elliptical, triangular, rectangular, quadric, or polygonal shape. If the cross section is circular, the aforementioned maximum transverse dimension of the elongated susceptor element corresponds to the diameter of the susceptor element, which is greatest along the length dimension of the elongated susceptor element. If the cross section is oval or elliptical, the aforementioned maximum transverse dimension of the elongated susceptor element corresponds to the length of the semi-major axis of the oval or elliptical cross section, which is greatest along the length dimension of the elongated susceptor element. If the cross section is square or approximately rectangular, the aforementioned maximum transverse dimension of the elongated susceptor element corresponds to the length of the edge / long edge of the square / rectangular cross section.

[0022] Generally, the term "susceptor element" as used herein refers to an element comprising a susceptor material capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This may be the result of at least one of hysteresis loss and eddy currents induced in the susceptor material, depending on the electrical and magnetic properties of the susceptor material. Hysteresis loss occurs in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains in the material being switched under the influence of the alternating electromagnetic field. Eddy currents may be induced if the susceptor material is electrically conductive. In the case of an electrically conductive ferromagnetic susceptor or an electrically conductive ferrimagnetic susceptor, heat can be generated due to both eddy currents and hysteresis loss.

[0023] Thus, the susceptor material of the elongated susceptor elements is generally electrically conductive and at least one of ferromagnetic and / or ferrimagnetic. In particular, the susceptor material of the elongated susceptor elements may be non-conductive but may be ferromagnetic or ferrimagnetic. Alternatively, the susceptor material of the elongated susceptor elements may be electrically conductive but not ferromagnetic or ferrimagnetic.

[0024] The susceptor material of the elongated susceptor elements preferably comprises or consists of a metal, such as ferritic iron, or stainless steel, particularly stainless steel grade 410, grade 420, or grade 430. Alternatively, the susceptor material of the elongated susceptor elements may comprise a ferrimagnetic ceramic.

[0025] In addition to the susceptor material, the elongated susceptor element may further include a ferromagnetic or ferrimagnetic temperature marker material. The susceptor material is optimized for heat loss and therefore heating efficiency, while the temperature marker material is a magnetic (ferromagnetic or ferrimagnetic) material selected to have a Curie temperature that essentially corresponds to a predetermined temperature point in the heating process. When the temperature of the susceptor arrangement and the aerosol-forming substrate reaches the Curie temperature of the temperature marker material, the magnetic permeability of the temperature marker material decreases to 1, resulting in a change in its magnetic property from ferromagnetic or ferrimagnetic to paramagnetic. The change in magnetic property is achieved by a temporary change in the electrical resistance of the susceptor arrangement and a temporary change in the inductance of the induction heating arrangement. Therefore, by monitoring the corresponding change in the current through the induction heating arrangement used to heat the susceptor arrangement, which generates the alternating magnetic field, it is possible to detect when the temperature marker material reaches its Curie temperature, and therefore the predetermined temperature point.

[0026] Specifically, the temperature maker material may be selected to have a Curie temperature that essentially corresponds to a predetermined maximum heating temperature of the susceptor arrangement. The maximum desired heating temperature may be defined to be approximately the temperature to which the susceptor arrangement should be heated to generate an aerosol from the aerosol-forming substrate. However, the maximum desired heating temperature should be low enough to avoid local overheating or even combustion of the aerosol-forming substrate. Preferably, the Curie temperature of the temperature maker material should be below the ignition point of the aerosol-forming substrate to be heated.

[0027] The temperature maker material may have a Curie temperature of less than 500° C., preferably less than or equal to 400° C., specifically less than or equal to 390° C. For example, the temperature maker material of the elongated susceptor element may have a Curie temperature in the range of 180° C. to 420° C., specifically 210° C. to 380° C., preferably 250° C. to 380° C. The temperature maker material is primarily a functional material that provides a temperature marker by virtue of its Curie temperature and may also contribute to the inductive heating of the susceptor arrangement.

[0028] The temperature maker material of the elongated susceptor elements may comprise or consist of nickel or a nickel alloy. As an example, the temperature maker material of the elongated susceptor elements may be a Ni-Fe alloy, specifically a Ni-Fe alloy containing 75% to 85% by weight of Ni and 10% to 25% by weight of Fe, more specifically 79% to 82% by weight of Ni and 13% to 15% by weight of Fe, or - 79% to 82% by weight of Ni, 4% to 6% by weight of Mo, less than 1% by weight of Si and Mn combined together, and 13% to 15% by weight of Fe, or - may comprise or consist of a Ni-Fe alloy comprising 77% by weight of Ni, 16% by weight of Fe, 5% by weight of Cu, and one of 2% by weight of Cr and Mo, or 77% by weight of Ni, 14-15% by weight of Fe, 4% by weight of Cu, and one of 4% by weight of Mo.

[0029] As another example, the temperature marker material may be an Fe—Ni—Cr alloy, specifically 50% by weight Ni, 11% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 210, which has a Curie temperature of about 210°C), or 50% by weight Ni, 10% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 230, which has a Curie temperature of about 230°C), or 50% by weight Ni, 9% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 260, which has a Curie temperature of about 260°C), or - 50% by weight Ni, 9% by weight Cr, max. 1% by weight Si, and max. 1% by weight Mn, the balance being Fe, or - 50% by weight Ni, 10% by weight Cr, max. 1% by weight Si, and max. 1% by weight Mn, the balance being Fe, or - may comprise or consist of an Fe-Ni-Cr alloy containing one of the following by weight: 50% Ni, 11% Cr, max. 1% Si and max. 1% Mn, the remainder being Fe.

[0030] As yet another example, the temperature maker material of the elongated susceptor elements may include or consist of a Ni-Fe alloy available from Hitachi under the designation "MS-10" having a Ni content of 36.1% by weight and a Curie temperature of 213° C. Similarly, the temperature maker material of the elongated susceptor elements may include or consist of a Ni-Fe alloy available from Hitachi under the designation "MS-16" having a Ni content of 36.4% by weight and a Curie temperature of 221.5° C.

[0031] The susceptor element may be formed such that the susceptor material is at least partially, preferably completely, surrounded or covered by the temperature maker material. That is, the temperature maker material may be a coating or layer that at least partially, preferably completely, surrounds or covers the susceptor material. Vice versa, the susceptor element may be formed such that the temperature maker material is at least partially, preferably completely, surrounded or covered by the susceptor material. That is, the susceptor material may be a coating or layer that at least partially, preferably completely surrounds and covers the temperature maker material.

[0032] Advantageously, the temperature maker material and the susceptor material may be intimately coupled to one another. For example, one of the temperature maker material and the susceptor material may be plated, deposited, coated, clad, or welded onto the other material. In particular, one of the temperature maker material and the susceptor material may be applied onto the other layer by spraying, dip coating, roll coating, electroplating, or cladding. Any of the above configurations fall within the scope of the term "intimately coupled" as used herein.

[0033] It is also possible for the susceptor material of the susceptor element itself to have the temperature marker function. That is, the elongated susceptor element may include a single material that acts both as a susceptor material and as a temperature marker material. For example, this single material may be the susceptor material plus one of the materials described above with respect to the susceptor temperature marker material.

[0034] Instead of, or in addition to, temperature marker material as part of the elongated susceptor elements, the susceptor arrangement may include one or more sensitive temperature maker elements in addition to a plurality of elongated susceptor elements.

[0035] Like the susceptor element, the one or more temperature maker elements may comprise or consist of a ferromagnetic or ferrimagnetic temperature maker material. Like the temperature maker material of the susceptor element, the ferromagnetic or ferrimagnetic temperature maker material of the one or more temperature maker elements may be selected to have a Curie temperature that essentially corresponds to a predetermined temperature point in the heating process, specifically a predetermined maximum heating temperature of the susceptor arrangement. Thus, the sensitive temperature maker material of the one or more temperature maker elements may have a Curie temperature of less than 500°C, preferably 400°C or less, specifically 390°C or less. For example, the temperature maker material of the temperature maker element may have a Curie temperature in the range of 180°C to 420°C, specifically 210°C to 380°C, preferably 250°C to 380°C.

[0036] The ferromagnetic or ferrimagnetic temperature maker material of the one or more temperature maker elements may be one of the materials disclosed above with respect to the temperature maker material of the susceptor element. That is, the ferromagnetic or ferrimagnetic temperature maker material of the one or more temperature maker elements may comprise or consist of nickel or a nickel alloy. By way of example, the temperature maker material of the one or more temperature maker elements may be a Ni-Fe alloy, in particular a Ni-Fe alloy containing 75% to 85% by weight Ni and 10% to 25% by weight Fe, more particularly 79% to 82% by weight of Ni and 13% to 15% by weight of Fe, or - 79% to 82% by weight of Ni, 4% to 6% by weight of Mo, less than 1% by weight of Si and Mn combined together, and 13% to 15% by weight of Fe, or 77% by weight of Ni, 16% by weight of Fe, 5% by weight of Cu, and 2% by weight of one of Cr and Mo, or - comprising or consisting of a Ni-Fe alloy containing one of the following by weight: 77% Ni, 14-15% Fe, 4% Cu and 4% Mo.

[0037] In another embodiment, the temperature marker material of one or more of the temperature maker elements is an Fe—Ni—Cr alloy, specifically 50% by weight Ni, 11% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 210, which has a Curie temperature of about 210°C), or 50% by weight Ni, 10% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 230, which has a Curie temperature of about 230°C), or 50% by weight Ni, 9% by weight Cr, and the remainder Fe (an alloy sold under the trade name Phytherm 260, which has a Curie temperature of about 260°C), or - 50% by weight Ni, 9% by weight Cr, max. 1% by weight Si, and max. 1% by weight Mn, the balance being Fe, or - 50% by weight Ni, 10% by weight Cr, max. 1% by weight Si, and max. 1% by weight Mn, the balance being Fe, or - may comprise or consist of an Fe-Ni-Cr alloy containing one of the following by weight: 50% Ni, 11% Cr, max. 1% Si and max. 1% Mn, the remainder being Fe.

[0038] As yet another example, the temperature maker material of one or more temperature maker elements may include or consist of a Ni-Fe alloy available from Hitachi under the designation "MS-10" having a Ni content of 36.1 wt. % and a Curie temperature of 213° C. Similarly, the temperature maker material of the elongated susceptor elements may include or consist of a Ni-Fe alloy available from Hitachi under the designation "MS-16" having a Ni content of 36.4 wt. % and a Curie temperature of 221.5° C.

[0039] Similar to the susceptor elements, the temperature maker elements may be dispersed throughout the aerosol-forming substrate.

[0040] Conversely, the susceptor arrangement may include a single temperature maker element disposed within the aerosol-generating article such that the aerosol-generating article experiences an alternating magnetic field provided by the aerosol-generating device with which it is used.

[0041] Generally, the one or more temperature maker elements may be particulate, isodimensional, oblate, or elongated temperature maker elements, specifically elongated temperature maker elements having the same shape and / or dimensions as the elongated susceptor element. When the susceptor arrangement includes a single temperature maker element, the single temperature maker element may have or be one of the following shapes: rod, pin, blade, particle, sheet, mesh, thread, fiber, wire, or filament. When the susceptor arrangement includes multiple temperature maker elements, the temperature maker element may have or be one of the following shapes: particle, thread, fiber, wire, or filament, spherical or quasi-spherical, oblate cylindrical, or oblate ellipsoid, or flake or plate.

[0042] When the thermal marker elements have an elongated shape, they may be dispersed throughout the aerosol-forming substrate, similar to the elongated susceptor elements, either randomly oriented, within a certain angular range, or oriented parallel to a predetermined reference axis of the article. Specifically, the thermal marker elements may be aligned within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor element and the predetermined reference axis of the article, specifically the length axis of the article, is within a range of +30° to −30°, specifically +25° to −25°, or more specifically +10° to −10°. Again, the predetermined reference axis of the article is preferably provided by the orientation of an alternating magnetic field provided by an aerosol-generating device used with the article.

[0043] Similar to the elongated susceptor elements, the one or more temperature maker elements may include an outer protective coating, in particular an outer anti-corrosion coating, to make the one or more temperature maker elements resistant to external influences, in particular corrosive influences.

[0044] Although the present invention is described herein with respect to elongated susceptor elements having a length dimension greater than either transverse dimension perpendicular to the length dimension, i.e., 1D elongated susceptor elements having a greater extent in one major dimension than in the other two dimensions perpendicular to the major dimension, it equally applies to susceptor elements having a greater extent in two (perpendicular) major dimensions than in the other dimensions perpendicular to the major dimension. Such susceptor elements are also referred to as 2D elongated susceptor elements. Specifically, the present invention also applies to susceptor elements having length and width dimensions greater than the thickness direction, and the length dimension may be greater than or substantially equal to the width dimension. More specifically, the present invention also applies to susceptor elements having either an oblate cylindrical shape (e.g., coin-shaped), an oblate ellipsoid shape (e.g., lens-shaped), or a flake or plate-like shape. For these susceptor elements, the same features and advantages described herein with respect to (1D) elongated susceptor elements can be expressed in a similar manner by essentially replacing the term "maximum length dimension of the (1D) elongated susceptor element" with "maximum extent in two major dimensions of the 2D elongated susceptor element" and replacing "maximum transverse dimension of the (1D) elongated susceptor element" with "maximum extent in the remaining (non-major) dimension of the 2D elongated susceptor element."

[0045] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate capable of releasing a volatile compound when heated to form an aerosol. The aerosol-generating article may be a consumable product, particularly a consumable product that is discarded after a single use. For example, the article may be an elongated or rod-shaped article. The elongated or rod-shaped article may have a shape similar to that of a conventional cigarette. Specifically, such an article may have a circular, oval, elliptical, square, rectangular, triangular, or polygonal cross section. As another example, the article may be a cartridge containing a liquid aerosol-forming substrate to be heated.

[0046] As used herein, the term "aerosol-forming substrate" refers to a substrate formed from or including an aerosol-forming material capable of releasing a volatile compound upon heating to generate an aerosol. Preferably, the aerosol-forming substrate is intended to be heated, rather than combusted, to release the aerosol-forming volatile compound. Such a substrate may therefore be referred to as a heat-non-combustion aerosol-forming substrate. Similarly, an aerosol-generating article comprising such an aerosol-forming substrate may be referred to as a heat-non-combustion aerosol-generating article.

[0047] Generally, the aerosol-forming substrate may include at least one aerosol former and at least one sensory material, both of which are volatilizable when heated. The sensory material may include at least one of a tobacco-containing material, a nicotine-containing material, and a flavoring material. Examples of suitable aerosol formers include glycerin and propylene glycol. Examples of flavoring materials may include plant extracts and natural or artificial flavors.

[0048] The aerosol-forming substrate may be a solid aerosol-forming substrate, a liquid aerosol-forming substrate, a gel-like aerosol-forming substrate, or any combination thereof. For example, the aerosol-forming substrate may include both solid and liquid components.

[0049] As described above, the aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. For example, the aerosol-forming substrate may comprise a porous substrate or foam based on a filler including tobacco fiber or cut tobacco material. Specifically, the aerosol-forming substrate may comprise a reconstituted tobacco material or a tobacco-containing slurry. Thus, the aerosol-generating article may be a tobacco-containing article. Alternatively, or additionally, the aerosol-forming substrate may comprise a non-tobacco material. For example, the aerosol-forming substrate may comprise a porous substrate or foam based on plant fiber, or a filler including chopped plant material, or cellulose or cellulosic fiber containing a flavoring substance. The aerosol-forming substrate may also comprise other additives and ingredients (such as nicotine or flavoring agents).

[0050] As another example, the article may comprise a plurality of elongated susceptor elements in combination with an aerosol-forming substrate comprising a nicotine-containing material, organic fibers, a binder, and an aerosol former. According to yet another example, the article may comprise a plurality of elongated susceptor elements in contact with a substrate comprising tobacco cut filler. As yet another example, the article may comprise a plurality of elongated susceptor elements embedded within a gel-like aerosol-forming substrate. In particular, the aerosol-forming substrate may also be a paste-like material, a sachet of porous material comprising the aerosol-forming substrate, or loose tobacco mixed with, for example, a gelling agent or adhesive, which may include a common aerosol former such as glycerin, which is compressed or molded into a plug.

[0051] The aerosol-forming substrate is preferably made from a sheet material. For example, the aerosol-forming substrate may be made from a crimped tobacco sheet containing tobacco material, organic fibers, a binder, and an aerosol former. Alternatively, the aerosol-forming substrate may be made from a sheet material containing a nicotine-containing material, organic fibers, a binder, and an aerosol former. As yet another alternative, the aerosol-forming substrate may be made from a sheet material containing tobacco cut filler. In this regard, it has been found that the aerosol-generating article is simple to manufacture when the susceptor elements are applied to the aerosol-forming substrate in the form of a sheet material, particularly with regard to the preferred alignment of the elongated susceptor elements with respect to the predetermined reference axis of the article. This may be the result of a manufacturing process that includes deposition of susceptor elements on the outer surface of the sheet material, either during a primary process in which the sheet material is manufactured, or during a secondary process in which the sheet material is machined and combined with other semi-finished products to obtain the final product. As a result of this, the elongated susceptor elements may ultimately be disposed on the outer surface of the sheet material or may be at least partially embedded within the sheet material near its outer surface. This may be observed even when the sheet material is subsequently machined, for example, crimped and assembled, such as to form a substrate plug in the final article. If present, one or more temperature maker elements may also be disposed on the outer surface of the sheet material or may be at least partially embedded within the sheet material near its outer surface, as described above with respect to the elongated susceptor elements.

[0052] Preferably, the aerosol-generating article may be a rod-shaped article. Specifically, the cylindrical article may comprise one or more of a distal forward plug element, a base element, a first tube element, a second tube element, and a filter element. The base element preferably comprises at least one heated aerosol-forming substrate and a susceptor arrangement having a plurality of elongated susceptor elements dispersed throughout the substrate. The base element may have a length of 10 to 14 millimeters, for example 12 millimeters. The susceptor arrangement may extend along the entire length of the base element, or the length of the extension may be shorter than the length of the base element.

[0053] The first tube element is distal to the second tube element. Preferably, the first tube element is proximal to the base element, and the second tube element is proximal to the first tube element and distal to the filter element, i.e., between the first tube element and the filter element. At least one of the first tube element and the second tube element may comprise a central air passage. The cross-section of the central air passage of the second tube element may be larger than the cross-section of the central air passage of the first tube element. Preferably, at least one of the first tube element and the second tube element may comprise a hollow cellulose acetate tube. At least one of the first tube element and the second tube element may have a length of 6 to 10 millimeters, for example 8 millimeters.

[0054] The filter element preferably functions as a mouthpiece or is part of a mouthpiece together with a second tube element. As used herein, the term "mouthpiece" refers to the portion of the article through which the aerosol exits the aerosol-generating article. The filter element may have a length of 10 to 14 millimeters, for example 12 millimeters.

[0055] The distal front plug element may be used to cover and protect the distal front end of the base element. The distal front plug element may have a length of 3 to 6 millimeters, for example 5 millimeters. The distal front plug element may be made of the same material as the filter element.

[0056] All of the aforementioned elements may be disposed consecutively along the longitudinal axis of the article in the order described above, with the distal front plug element preferably disposed at the distal end of the article and the filter element preferably disposed at the proximal end of the article. Each of the aforementioned elements may be substantially cylindrical. Specifically, all of the elements may have the same external cross-sectional shape and / or dimensions.

[0057] Additionally, the elements may be surrounded by one or more outer wrappers to hold the elements together, maintain the desired cross-sectional shape of the rod-shaped article, etc. The wrappers are preferably made of paper. The wrappers may further comprise an adhesive that bonds the overlapping free ends of the wrappers to one another. For example, the distal forward plug element, the base element, and the first tubing element may be surrounded by a first wrapper, and the second tubing element and the filter element may be surrounded by a second wrapper. The second wrapper may also surround at least a portion of the first tubing element (i.e., after being wrapped on top of the first wrapper) to connect the distal forward plug element, the base element, and the first tubing element surrounded by the first wrapper to the second tubing element and the filter element. The second wrapper may comprise perforations around its circumference.

[0058] According to further aspects of the present invention, there is also provided an aerosol generating system comprising an aerosol-generating article according to the present invention and as described herein, and an inductively heated aerosol generator for use with the aerosol-generating article.

[0059] The term "aerosol-generating device," as used herein, describes an electrically operated device for interaction with an aerosol-generating article to generate an aerosol within the article by heating an aerosol-forming substrate through interaction of a susceptor arrangement with an alternating magnetic field provided by the device. The aerosol-generating device is preferably a smoking device for generating an aerosol that can be directly inhaled by a user through the user's mouth. Specifically, the aerosol-generating device is a handheld aerosol-generating device.

[0060] The device may comprise a receiving cavity for removably receiving at least a portion of each aerosol-generating article.

[0061] The aerosol generating device may further comprise an induction heating arrangement constructed and arranged to generate an alternating magnetic field within the receiving cavity to inductively heat the susceptor arrangement when an article is received within the cavity.

[0062] To generate the alternating magnetic field, the induction heating arrangement may include at least one induction coil surrounding at least a portion of the susceptor arrangement used in the system. The at least one induction coil may be a helical coil or a flat, planar coil, specifically a pancake coil or a curved, planar coil. The aerosol generating device and aerosol-generating article are preferably configured so that the susceptor arrangement is disposed within a cavity of the device, specifically within the interior space of the at least one induction coil, such that the article experiences the alternating magnetic field when received within the aerosol generating device. The induction heating arrangement may further include an alternating current (AC) generator. The AC generator may be powered by a power supply of the aerosol generating device. The AC generator is operably coupled to the 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 that passes through the at least one induction coil to generate the alternating magnetic field. The AC current may be supplied to the at least one induction coil continuously after activation of the system, or intermittently (e.g., with each puff). The induction heating arrangement preferably comprises a DC / AC converter including an LC network, the LC network preferably comprising a series connection of a capacitor and an inductor, and the DC / AC converter may be connected to a DC power source.

[0063] The induction heating arrangement is preferably configured to generate a high frequency magnetic field, as referred to herein, the frequency of which may be in the range of 500 kHz (kilohertz) to 30 MHz (megahertz), in particular 5 MHz (megahertz) to 15 MHz (megahertz), preferably 5 MHz (megahertz) to 10 MHz (megahertz).

[0064] The aerosol generating device may further include a controller configured to control the operation of the heating process. The controller may be the overall controller of the aerosol generating device or may be part of the overall controller of the aerosol generating device. The controller may include a microprocessor (e.g., a programmable microprocessor), a microcontroller, or an application specific integrated circuit (ASIC) or other electronic circuit capable of providing control. The controller may include additional electronic components, such as at least one DC / AC converter and / or a power amplifier (e.g., a class C power amplifier, a class D power amplifier, or a class E power amplifier). Specifically, the induction source may be part of the controller.

[0065] The aerosol generating device may also include a power source, specifically a DC power source configured to provide a DC supply voltage and a DC supply current to the induction source. The power source is preferably a battery, such as a lithium iron phosphate battery. The power source may be rechargeable. The power source may have a capacity that allows for storage of energy sufficient for one or more user experiences. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, or a multiple of six minutes. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffs, or for discontinuous activation of the induction source.

[0066] Further features and advantages of the aerosol-generating system are described with respect to the aerosol-generating article and therefore apply equally. [Example]

[0067] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0068] Example 1: 1. An aerosol-generating article for use with an induction-heated aerosol-generating device, the article comprising an aerosol-forming substrate and a susceptor arrangement for heating the aerosol-forming substrate by interaction of the susceptor arrangement with an alternating magnetic field provided by the aerosol-generating device, the susceptor arrangement comprising a plurality of elongated susceptor elements comprising a susceptor material dispersed throughout the aerosol-forming substrate, the elongated susceptor elements being aligned within the aerosol-forming substrate such that an angle between a length dimension of the elongated susceptor element and a predetermined reference axis of the article, in particular the length axis of the article, is in the range of +30 degrees to -30 degrees. Example 2: An aerosol-generating article as described in Example 1, wherein the elongated susceptor elements are aligned within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor elements and a predetermined reference axis of the article, in particular the length axis of the article, is within the range of +25 degrees to -25 degrees, preferably +10 degrees to -10 degrees. Example 3: 3. An aerosol-generating article according to any one of Examples 1 or 2, wherein the elongated susceptor elements are aligned within the aerosol-forming substrate substantially parallel to a predetermined reference axis of the article, specifically the length axis of the article. Example 4: An aerosol-generating article as described in any one of Examples 1 to 3, wherein the ratio of the maximum linear dimension of the elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the (maximum) linear dimension is greater than 4, preferably greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35. Example 5: An aerosol-generating article according to any one of Examples 1 to 4, wherein the ratio of the maximum length dimension of the elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the (maximum) length dimension is in the range of 4 to 500, specifically 10 to 300, preferably 20 to 200, more preferably 30 to 100. Example 6: An aerosol-generating article according to any one of Examples 1 to 5, wherein the maximum linear dimension of the elongated susceptor elements is in the range of 0.02 micrometers to 50 millimeters, specifically 1 micrometer to 16 millimeters, preferably 0.1 millimeters to 5 millimeters. Example 7: 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein the maximum transverse dimension of the elongated susceptor elements is in the range of 0.005 micrometers to 500 micrometers, particularly 0.1 micrometers to 150 micrometers, and preferably 20 micrometers to 100 micrometers. Example 8: An aerosol-generating article according to any one of Examples 1 to 7, wherein the elongate susceptor elements have a maximum transverse dimension of 500 micrometers, particularly 100 micrometers, preferably 10 micrometers, more preferably 1 micrometer or less. Example 9: 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the density of the elongated susceptor elements in the aerosol-forming substrate is in the range of 0.001 susceptor elements per cubic millimeter to 30 susceptor elements per cubic millimeter, specifically 0.1 susceptor elements per cubic millimeter to 10 susceptor elements per cubic millimeter, or the mass density of the elongated susceptor elements in the aerosol-forming substrate is in the range of 0.002 milligrams of susceptor mass per cubic millimeter to 0.3 milligrams of susceptor mass per cubic millimeter, specifically 0.01 milligrams of susceptor mass per cubic millimeter to 0.1 milligrams of susceptor mass per cubic millimeter. Example 10: 10. An aerosol-generating article according to any one of Examples 1 to 9, wherein the elongated susceptor element has one of an elongated cylindrical shape or an oblate ellipsoid shape. Example 11: An aerosol-generating article described in any one of Examples 1 to 10, wherein the elongated susceptor elements are one of fiber elements, particularly chopped fiber elements or milled fiber elements, or wire elements, or thread elements, or particle elements, or rod elements. Example 12: An aerosol-generating article according to any one of Examples 1 to 11, wherein the cross section of the elongated susceptor element in a plane perpendicular to the length dimension of the elongated susceptor element has a circular, oval, elliptical, triangular, rectangular, quadric, or polygonal shape. Example 13: 13. An aerosol-generating article according to any one of Examples 1 to 12, wherein the susceptor material of the elongated susceptor elements is electrically conductive and at least one of ferromagnetic and ferrimagnetic. Example 14: An aerosol-generating article according to any one of Examples 1 to 13, wherein the susceptor material of the elongated susceptor element comprises or consists of a metal, such as ferritic iron, or stainless steel, particularly grade 410, grade 420, or grade 430 stainless steel, or a ferrimagnetic ceramic. Example 15: 15. The aerosol-generating article of any one of Examples 1 to 14, wherein the elongated susceptor element further comprises a ferromagnetic or ferrimagnetic temperature maker material in addition to the susceptor material. Example 16: 16. The aerosol-generating article of example 15, wherein the temperature maker material of the elongated susceptor element comprises or consists of nickel or a nickel alloy. Example 17: 17. The aerosol-generating article of any one of Examples 15-16, wherein the temperature maker material of the elongated susceptor element has a Curie temperature in the range of 180°C to 420°C, specifically 210°C to 380°C, preferably 250°C to 380°C. Example 18: 18. The aerosol-generating article of any one of Examples 15-17, wherein the susceptor material is surrounded by a temperature maker material. Example 19: 19. The aerosol-generating article of any one of Examples 1 to 18, wherein the elongated susceptor element comprises an outer protective coating surrounding the susceptor material and, if present, the temperature marker material. Example 20: 20. An aerosol-generating article according to any one of Examples 1 to 19, wherein in addition to the plurality of elongated susceptor elements, the susceptor arrangement comprises one or more temperature maker elements comprising a ferromagnetic or ferrimagnetic temperature maker material. Example 21: 21. The aerosol-generating article of Example 20, wherein the temperature maker element is dispersed throughout the aerosol-forming substrate. Example 22: 22. An aerosol-generating article according to any one of Examples 20 or 21, wherein the temperature maker material of the one or more temperature maker elements comprises or consists of nickel or a nickel alloy. Example 23: 23. An aerosol-generating article according to any one of Examples 20 to 22, wherein the temperature maker material of one or more temperature maker elements has a Curie temperature in the range of 180°C to 420°C, specifically 210°C to 380°C, preferably 250°C to 380°C. Example 24: 24. The aerosol-generating article of any one of Examples 20-23, wherein the one or more temperature maker elements include an outer protective coating. Example 25: An aerosol-generating article described in any one of Examples 20 to 24, wherein one or more temperature maker elements are particulate temperature maker elements, or isodimensional temperature maker elements, or oblate temperature maker elements or elongated temperature makers, specifically elongated temperature maker elements having the same shape and / or the same dimensions as the elongated susceptor elements. Example 26: An aerosol-generating article described in any one of Examples 1 to 25, wherein the aerosol-forming substrate is made from a sheet material and the elongated susceptor elements are disposed on an outer surface of the sheet material or are at least partially embedded within the sheet material near the outer surface of the sheet material. Example 27: 27. An aerosol-generating article according to any one of Examples 1 to 26, wherein the aerosol-forming substrate comprises at least one aerosol former and at least one sensate material that is volatilizable when heated. Example 28: An aerosol generating system comprising the aerosol-generating article according to any one of Examples 1 to 27 and an induction heating aerosol generator for use with the article.

[0069] The embodiments will now be further described with reference to the figures. [Brief explanation of the drawings]

[0070] [Figure 1] FIG. 1 illustrates schematically one exemplary embodiment of an inductively heatable aerosol-generating article according to the present invention, comprising a susceptor arrangement having a plurality of elongated susceptor elements. [Figure 2] FIG. 2 illustrates schematically an exemplary embodiment of an aerosol-generating system comprising an aerosol-generating article according to FIG. [Figure 3] FIG. 3 shows a detail of the susceptor arrangement of the article according to FIG. [Figure 4] FIG. 4 shows details of another embodiment of the susceptor arrangement. [Figure 5] FIG. 5 shows details of yet another embodiment of a susceptor arrangement. [Figure 6] FIG. 6 shows details of yet another embodiment of a susceptor arrangement. [Figure 7] FIG. 7 shows details of an alternative embodiment of an elongated susceptor element. [Figure 8] FIG. 8 shows details of another alternative embodiment of the elongated susceptor element. [Figure 9] FIG. 9 shows a detail of the base element of the article according to FIG. DETAILED DESCRIPTION OF THE INVENTION

[0071] FIG. 1 illustrates, in a schematic representation (not to scale), one exemplary embodiment of an inductively heatable aerosol-generating article 100 according to the present invention. The aerosol-generating article 100 is a substantially rod-shaped consumable product comprising five elements arranged consecutively in coaxial alignment: a distal forward plug element 150, a base element 110, a first tube element 140, a second tube element 145, and a filter element 160. The distal forward plug element 150 is disposed at the distal end 102 of the article 100 and covers and protects the distal forward end of the base element 110, while the filter element 160 is disposed at the proximal end 103 of the article 100. Both the distal forward plug element 150 and the filter element 160 may be made of the same filter material. The filter element 160 preferably functions as a mouthpiece, particularly as part of the mouthpiece together with the second tube element 145. The filter element may have a length of 10 to 14 millimeters, for example 12 millimeters, and the distal front plug element 150 may have a length of 3 to 6 millimeters, for example 5 millimeters. Each of the first and second tube elements 140, 145 is a hollow cellulose acetate tube having a central air passage 141, 146, the cross section of the central air passage 146 of the second tube element 145 being larger than the cross section of the central air passage 141 of the first tube element 140. The first tube element 140 and the second tube element 145 may have a length of 6 to 10 millimeters, for example 8 millimeters. The substrate element 110 includes a heated aerosol-forming substrate 130 and a susceptor arrangement 120 for heating the substrate 130. According to the present invention, the susceptor arrangement 120 includes a plurality of elongated susceptor elements 121 comprising a ferromagnetic or ferrimagnetic susceptor material dispersed throughout the aerosol-forming substrate 130 to achieve uniform heating of the substrate 130. The substrate elements 110 may have a length of 10 millimeters to 14 millimeters, e.g., 12 millimeters. Each of the aforementioned elements 150, 110, 140, 145, and 160 may be substantially cylindrical. Specifically, all of the elements 150, 110, 140, 145, and 160 may have the same external cross-sectional shape and dimensions.Additionally, the elements may be surrounded by one or more outer wrappers, such as to hold the elements together and to maintain the desired cross-sectional shape of the rod-shaped article. In this embodiment, the distal forward plug element 150, the base element 110, and the first tube element 140 are surrounded by the first wrapper 140, while the second tube element 145 and the filter element 160 are surrounded by the second wrapper 172. The second wrapper 172 also surrounds at least a portion of the first tube element 140 (after being wrapped by the first wrapper 171) and connects the distal forward plug element 150, the base element 110, and the first tube element 140, which are surrounded by the first wrapper 171, to the second tube element 145 and the filter element 160. The first wrapper 171 and the second wrapper 172 are preferably made of paper. Additionally, the second wrapper 172 may be provided with perforations around its periphery (not shown). The wrappers 171, 172 may further include an adhesive that adheres the overlapping free ends of the wrappers to one another.

[0072] As shown in FIG. 2 , the aerosol-generating article 100 is configured for use with an induction heating aerosol generating device 10. The device 10 and the article 100 together form an aerosol generation system 1 according to the present invention. The aerosol generating device 10 comprises a cylindrical receiving cavity 20 defined within a proximal portion 12 of the device 10, for receiving at least a distal portion of the article 100 therein. The device 10 further comprises an induction heating arrangement including an induction coil 30 for generating a high-frequency alternating magnetic field within the cavity 20. In this embodiment, the induction coil 30 is a helical coil that circumferentially surrounds the cylindrical receiving cavity 20. Due to the cylindrical shape of the helical coil 30, the alternating magnetic field within the cavity is substantially homogenous within the space enclosed by the helical coil induction coil 30, with the magnetic field lines extending substantially parallel to the longitudinal axis of the cavity 20. The induction coil 30 is arranged so that the substrate portion 110 of the article 100, including the susceptor arrangement 120, is exposed to an alternating magnetic field as the article 100 is inserted into the cavity 20 of the apparatus 10. Thus, upon activation of the induction heating arrangement, the susceptor elements 121 of the susceptor arrangement 120 heat due to eddy currents and / or hysteresis losses induced by the alternating magnetic field, depending on the magnetic and electrical properties of the susceptor material of the susceptor elements 121. The susceptor arrangement 120 is heated to a temperature sufficient to vaporize the aerosol-forming substrate 130. As a result, volatile compounds are released from the aerosol-forming substrate 130 within the substrate element 110 to form an aerosol that can be drawn through the first and second tube elements 140, 145, and the filter element 160 toward the proximal end 103 of the article 100. Within the distal portion 13, the aerosol generating device 10 further comprises a DC power supply 40 and a controller 50 (shown only diagrammatically in FIG. 2) for supplying power and controlling the heating process. Apart from the induction coil 30, the induction heating arrangement is preferably an at least partially integral part of the controller 50.

[0073] FIG. 3 shows a detailed view (not to scale) of a portion of the substrate element 110 used in the aerosol-generating article 100 shown in FIG. 1 . As described above, the substrate element 110 includes a plurality of elongated susceptor elements 121, i.e., susceptor elements having a greater extent in one major dimension than in the two remaining dimensions. In this embodiment, the elongated susceptor elements 121 are chopped fiber elements having a substantially cylindrical shape. In accordance with the present invention, it has been found that substrate heating efficiency, and therefore extraction efficiency, is particularly enhanced when the susceptor elements have an elongated shape, i.e., a shape in which the length dimension of the susceptor element predominates over any transverse dimension perpendicular to the length dimension. As further explained above, the improved heating efficiency results from the fact that the strength of the demagnetizing field induced in the susceptor elements when exposed to the external alternating magnetic field of the induction heating arrangement is enhanced for elongated shapes compared to, for example, spherical shapes. The heating efficiency of a multi-element susceptor arrangement increases the more elements are aligned along their length dimension parallel to the external alternating magnetic field of the induction heating arrangement.

[0074] The heating efficiency of the substrate, and therefore the extraction efficiency, is particularly improved when the ratio of the maximum length dimension of the elongated susceptor elements to the maximum transverse dimension of the elongated susceptor elements perpendicular to the length dimension is greater than 4, in particular greater than 10, preferably greater than 20, and more preferably greater than 25. In the embodiment according to Figures 1 and 3, the chopped fiber elements have a maximum length dimension L in the range of 0.8 millimeters to 1.2 millimeters (average of about 1 millimeter) and a maximum transverse dimension T perpendicular to the length dimension L, i.e., a diameter T of about 25 micrometers. As a result, in the embodiment shown in Figures 1, 2, and 3, the ratio of the maximum length dimension L to the maximum transverse dimension T of the elongated susceptor elements 121 (geometry factor) is on average about 40, which is well above the preferred threshold of 4.

[0075] As mentioned above, heating efficiency is greatest when the elongated susceptor elements 121 are all aligned parallel to the orientation M of the alternating magnetic field. Accordingly, all of the elongated susceptor elements 121 in the base element 110 shown in Figures 1 and 3 are aligned along their length dimension substantially parallel to a predetermined reference axis of the article, here the length axis 101 of the article 100, which coincides with the orientation M of the magnetic field lines at the location of the base element 110 in the cavity 20 when the article 100 according to Figure 1 is engaged with the aerosol generating device shown in Figure 2.

[0076] The elongated susceptor elements 121 do not need to be aligned perfectly parallel to the length axis 101 of the article 100 and the orientation M of the magnetic field lines at the location of the substrate element 110 within the cavity 20. Even when the elongated susceptor elements 121 are aligned at a certain angular range about the length axis 101 of the article as shown in FIG. 4, the overall heating performance is still higher than for a susceptor arrangement having randomly oriented elongated susceptor elements. As shown in FIG. 4, the elongated susceptor elements 121 can be advantageously aligned within the aerosol-forming substrate 130 such that the angle β between the length dimension of the elongated susceptor elements and a predetermined reference axis of the article, specifically, the length axis 101 of the article 100, is in the range of +30 degrees to −30 degrees, specifically +25 degrees to −25 degrees, and more specifically +10 degrees to −10 degrees.

[0077] Nevertheless, when considering a collection of susceptor elements, the overall heating performance of a collection of elongated susceptor elements 121 is still higher on statistical average than that of a collection of equal-sized susceptor elements, even when the elongated susceptor elements 121 are not all parallel-aligned within a certain angular range, but are randomly oriented as shown in FIG. 5. Thus, the overall heating performance of the proposed susceptor arrangement 120 of elongated susceptor elements 121 is higher than for a similar configuration of equal-sized susceptor elements, regardless of whether the elongated susceptor elements are distributed throughout the substrate in a random orientation, or within a certain angular range, or parallel to the orientation M of the alternating magnetic field used for induction heating.

[0078] In addition to the plurality of elongated susceptor elements 121, the susceptor arrangement 120 according to the embodiment shown in FIGS. 1-6 includes a plurality of temperature maker elements 122 in the form of chopped fiber elements similar to the chopped fiber elements forming the elongated susceptor elements 121. The temperature maker elements 122 comprise a ferromagnetic temperature maker material selected to have a Curie temperature substantially corresponding to a predetermined maximum heating temperature of the susceptor arrangement 120. When the temperature of the susceptor arrangement 120 and the aerosol-forming substrate 130 reaches the Curie temperature of the temperature maker material, the magnetic permeability of the temperature maker material decreases to 1, resulting in a change in its magnetic property from ferromagnetic to paramagnetic. The change in magnetic property is achieved by a temporary change in the electrical resistance of the susceptor arrangement 120 as well as a temporary change in the inductance of the induction heating arrangement. Therefore, by monitoring the corresponding change in current through the induction heating arrangement of the apparatus 10, it is possible to detect when the temperature maker material reaches its Curie temperature, and therefore when a predetermined temperature point has been reached. Advantageously, the Curie temperature is below 500°C, in particular below 400°C, more particularly below 390°C, to avoid local overheating or even combustion of the aerosol-forming substrate 130. For example, the temperature maker material of the temperature maker elements may have a Curie temperature in the range of 180°C to 420°C, in particular between 210°C and 380°C, preferably between 250°C and 380°C. Preferably, the ferromagnetic or ferrimagnetic temperature maker material of the temperature maker elements 122 may comprise or consist of nickel or a nickel alloy. By way of example, the temperature maker material of one or more temperature maker elements may comprise or consist of a Ni-Fe alloy, in particular a Ni-Fe alloy containing 75% to 85% by weight of Ni and 10% to 25% by weight of Fe. As can be further seen from Figures 3-6, the temperature marker elements 122, like the susceptor elements 121, can be dispersed throughout the aerosol-forming substrate 130 either in a random orientation (Figure 5), or within a range of angles (Figure 4), or parallel to the orientation M of the alternating magnetic field used for induction heating (Figures 3 and 6).

[0079] As an alternative to the temperature maker element 122 shown in FIGS. 1-5, the susceptor element itself may comprise a ferromagnetic or ferrimagnetic temperature marker material having a Curie temperature selected to correspond to a predetermined maximum heating temperature of the susceptor arrangement. For example, as shown in FIG. 7, the elongated susceptor element 321 may be formed as a fiber element having a susceptor material 323 forming a fiber core surrounded by a temperature marker material 324. That is, the temperature marker material 324 may be a coating or layer surrounding the susceptor material 323. Advantageously, the temperature marker material 324 and the susceptor material 323 are intimately coupled to one another. For example, the temperature marker material 324 may be coated onto the susceptor material 323, such as by dip coating. As further shown in FIG. 7, the elongated susceptor element 321 may include an outer protective coating 325 surrounding the susceptor material 323 and the temperature marker material 324. The protective coating 325 is preferably an anti-corrosion coating that makes the susceptor element 321 resistant to external influences, in particular corrosive influences.

[0080] Instead of the chopped fiber elements shown in Figures 1-5, the susceptor arrangement 220 may include a plurality of elongated susceptor elements 221 in the form of thread or filament elements. This is shown in Figure 6. As in Figure 3, the thread or filament elements are arranged substantially parallel to the length axis 201 of the article, which in turn coincides with the orientation M of the magnetic field lines at the location of the substrate element for use with the aerosol generating device. The thread or filament elements may extend along the entire length dimension of the substrate element.

[0081] As an alternative to fiber, thread, or filament elements, the susceptor arrangement may include a plurality of elongated susceptor elements 421 in the form of particle elements. FIG. 8 shows an exemplary embodiment of such particle elements. The particle-like susceptor elements 421 have an oblate ellipsoid shape with a length dimension L of approximately 4.5 millimeters and a maximum transverse direction T of 1 millimeter, i.e., a shape factor of approximately 4.5. The susceptor elements 421 may be made, for example, of a ferrimagnetic ceramic material with a Curie temperature of less than 400° C. The particle-like susceptor elements 421 may be dispersed throughout the aerosol-forming substrate either randomly oriented, within a certain angular range, or parallel to the orientation M of the alternating magnetic field used for induction heating.

[0082] FIG. 9 shows a perspective view of a portion of the substrate element 110 included in the article 100 according to FIG. 1, including a detailed view (bottom right) of its internal structure, particularly the structure of the aerosol-forming substrate 130 and the susceptor arrangement 120. As can be seen from both the perspective view and the detailed view, the aerosol-forming substrate 130 is made from a sheet material. For example, the aerosol-forming substrate 130 may be made from a crimped tobacco sheet containing tobacco material, organic fibers, a binder, and an aerosol former assembled into the cylindrical shape of the substrate element 110. As can be further seen from the detailed view, the elongated susceptor elements 121 and the temperature marker elements 122 are disposed on the outer surface of the sheet material, where they can still be observed, even though the sheet material is crimped and assembled. This may be the result of a manufacturing process that includes deposition of the susceptor elements 121 and the temperature marker elements 122 on the outer surface of the sheet material, either during a primary process in which the sheet material is produced, or during a secondary process in which the sheet material is machined. In this regard, preferred alignment of the elongated susceptor elements 121 and temperature marker elements 122 relative to a predetermined reference axis of the article, here the longitudinal axis 101 of the final article 100, is particularly easy to achieve when the elongated susceptor elements 121 and temperature marker elements 122 are applied to the aerosol-forming substrate 130 when in the form of sheet material.

[0083] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5%. Within this context, the number A may be considered to include a numerical value that is within the typical standard error for measurement of the property that the number A modifies. In some cases, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. An aerosol-generating article for use with an induction-heated aerosol generating device, comprising: the article comprising an aerosol-forming substrate and a susceptor arrangement for heating the aerosol-forming substrate by interaction of the susceptor arrangement with an alternating magnetic field provided by the aerosol-generating device; the susceptor arrangement comprises a plurality of elongated susceptor elements including a susceptor material dispersed throughout the aerosol-forming substrate; the elongated susceptor elements are one of fiber elements, in particular chopped fiber elements or milled fiber elements, or wire elements, or thread elements, or particle elements, or rod elements; the elongated susceptor elements are aligned within the aerosol-forming substrate such that an angle between a length dimension of the elongated susceptor elements and a predetermined reference axis of the article, in particular the length axis of the article, is in the range of +30 degrees to -30 degrees; Aerosol-generating items.

2. 2. The aerosol-generating article of claim 1, wherein the elongated susceptor elements are aligned within the aerosol-forming substrate such that the angle between the length dimension of the elongated susceptor elements and the predetermined reference axis of the article, in particular the length axis of the article, is in the range of +25 degrees to -25 degrees, preferably +10 degrees to -10 degrees.

3. 3. The aerosol-generating article of claim 1, wherein the elongated susceptor elements are aligned within the aerosol-forming substrate substantially parallel to a predetermined reference axis of the article, specifically the length axis of the article.

4. 4. An aerosol-generating article according to claim 1, wherein the ratio of the maximum length dimension of the elongated susceptor elements to the maximum transverse dimension perpendicular to said length dimension is greater than 4, particularly greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35; or wherein the ratio of the maximum length dimension of the elongated susceptor elements to the maximum transverse dimension perpendicular to said length dimension is in the range from 4 to 500, particularly from 10 to 300, preferably from 20 to 200, and more preferably from 30 to 100.

5. 5. An aerosol-generating article according to any one of claims 1 to 4, wherein the maximum linear dimension of the elongated susceptor elements is in the range of 0.02 micrometers to 50 millimeters, particularly 1 micrometer to 16 millimeters, preferably 0.1 millimeters to 5 millimeters.

6. 6. An aerosol-generating article according to any one of claims 1 to 5, wherein the elongated susceptor elements have a maximum transverse dimension in the range of 0.005 micrometers to 500 micrometers, particularly 0.1 micrometers to 150 micrometers, preferably 20 micrometers to 100 micrometers, or wherein the maximum transverse dimension of the elongated susceptor elements is 500 micrometers, particularly 100 micrometers, preferably 10 micrometers, more preferably 1 micrometer or less.

7. 7. The aerosol-generating article of claim 1, wherein the elongated susceptor element has one of an elongated cylindrical shape or an oblate ellipsoid shape.

8. 8. The aerosol-generating article of claim 1, wherein the cross section of the elongated susceptor element in a plane perpendicular to the length dimension of the elongated susceptor element has a circular, oval, elliptical, triangular, rectangular, quadric, or polygonal shape.

9. 9. An aerosol-generating article according to any one of claims 1 to 8, wherein the susceptor material of the elongated susceptor elements is at least one of electrically conductive and either ferromagnetic or ferrimagnetic.

10. 10. An aerosol-generating article according to any one of claims 1 to 9, wherein the susceptor material of the elongated susceptor elements comprises or consists of a metal, such as ferritic iron, or stainless steel, in particular grade 410, grade 420 or grade 430 stainless steel, or a ferrimagnetic ceramic.

11. 11. An aerosol-generating article according to any preceding claim, wherein the elongated susceptor element further comprises, in addition to the susceptor material, a ferromagnetic or ferrimagnetic temperature maker material.

12. 12. The aerosol-generating article of claim 11, wherein the susceptor material is surrounded by the temperature maker material.

13. 13. An aerosol-generating article according to any preceding claim, wherein the elongated susceptor element comprises an outer protective covering surrounding the susceptor material and, if present, temperature marker material.

14. 14. An aerosol-generating article according to any preceding claim, wherein in addition to the plurality of elongated susceptor elements, the susceptor arrangement comprises one or more temperature maker elements comprising a ferromagnetic or ferrimagnetic temperature maker material.

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