Method and apparatus for aligning elongate susceptor elements in aerosol-forming substrate

Abstract

In a method of aligning elongated susceptor elements in an aerosol-forming substrate for use in an inductively heatable aerosol-generating article, the aerosol-forming substrate is provided in the form of a sheet material (4) to an alignment device (1) comprising at least one comb (5) having a plurality of teeth (6) arranged in a row. The aerosol-forming substrate comprises a plurality of elongate susceptor elements (3). The alignment device (1) and the sheet material (4) are moved relative to each other such that the elongate susceptor elements (3) passing between the teeth (6) of the at least one comb (5) are at least partially aligned relative to a reference axis of the sheet material (4).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method of aligning elongate susceptor elements in an aerosol-forming substrate for use in an inductively heatable aerosol-generating article. The present disclosure also relates to an apparatus for aligning elongate susceptor elements in an aerosol-forming substrate, in particular for use in the method according to the present disclosure. BACKGROUND

[0002] Aerosol-generating systems using inductive heating for generating an inhalable aerosol are well known from the prior art. Such systems can comprise an inductively heatable aerosol- generating device and a separate aerosol-generating article for use with the device. The article can comprise, among other components, an aerosol-forming substrate capable of forming an inhalable aerosol when heated, and an inductively heatable susceptor device in thermal proximity or direct physical contact with the substrate for heating the substrate. Inductive heating of the susceptor device is achieved by interaction of the susceptor device with an alternating magnetic field provided by the aerosol-generating device. In operation, the alternating magnetic field induces at least one of a heat-generating eddy current or magnetic hysteresis losses in the susceptor device, thereby heating the susceptor device to a temperature sufficient to release volatile compounds from the heated substrate, which can subsequently cool to form an aerosol.

[0003] Depending on the type of substrate and the shape of the article, different configurations of susceptor elements susceptor devices are known. As an example, the article can comprise a single solid susceptor element, such as a susceptor strip, embedded in a solid or gel-like aerosol-forming substrate within a substrate portion of the article. Although solid susceptor elements are readily available at low cost, they form a single central heat source which can lead to a non-uniform temperature distribution over the substrate portion. This is because direct heating of the substrate only occurs in the immediate vicinity of the susceptor element, while the peripheral regions of the substrate portion are only indirectly heated by means of heat conduction across adjacent substrate layers. In particular, the high temperature gradient can overheat the inner regions of the substrate portion in the vicinity of the susceptor element, while the temperature in the peripheral regions of the substrate portion can be too low to volatilize the substrate. Furthermore, the heating efficiency of this configuration is quite sensitive to the proper positioning of the susceptor element within the substrate. All of this can lead to a non-optimal utilization of the aerosol-forming substrate. Alternatively, articles comprising spherical or quasi-spherical susceptor particles uniformly dispersed throughout the aerosol-forming substrate have been proposed. Although leading to a more uniform heating of the substrate, the heating efficiency of this susceptor configuration is limited, which can also affect the extraction efficiency. Another alternative is to provide elongate susceptor elements distributed throughout the aerosol-forming substrate or deposited on a major surface of the aerosol-forming substrate. Although this leads to a more uniform heating of the aerosol-forming substrate, it has been found that the proper alignment of the elongate susceptor elements relative to the applied alternating magnetic field can further improve the heating efficiency. SUMMARY

[0004] It is therefore desirable to have an inductively heatable aerosol-forming substrate and an apparatus for manufacturing such an aerosol-forming substrate that has the advantages of the prior art solutions while mitigating their limitations. In particular, it is desirable to have an aerosol-forming substrate comprising elongated susceptor elements that are at least partially aligned so as to provide for a more efficient heating and utilization of the aerosol-forming substrate.

[0005] According to one aspect of the present disclosure, a method of aligning elongated susceptor elements in an aerosol-forming substrate for use in an inductively heatable aerosol-generating article is provided. The method comprises the step of providing the aerosol-forming substrate in the form of a sheet material to an alignment device, the aerosol-forming substrate comprising a plurality of elongated susceptor elements, the alignment device comprising at least one comb. The at least one comb comprises a plurality of teeth arranged in a row. The alignment device and the sheet material are moved relative to each other such that elongated susceptor elements passing between the teeth of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

[0006] The teeth of the at least one comb are configured such that the width of the space between two adjacent teeth (the width of the inter-tooth spacing) allows for elongated susceptor elements within a certain partial alignment range relative to the reference axis to pass. Elongated susceptor elements that lie outside the partial alignment range contact the teeth of the at least one comb and are oriented so as to be at least partially aligned, preferably relative to the reference axis of the sheet material, when passing between the teeth of the at least one comb. To this end, the teeth of the at least one comb can have any suitable cross-sectional shape, but preferably have or comprise a circular, oval, triangular or polygonal cross-sectional shape. To support the at least partial alignment of the elongated susceptor elements, the teeth can also have or comprise a sharp cross-sectional shape portion that contacts the elongated susceptor elements and facilitates the orientation of the elongated susceptor elements to achieve the at least partial alignment relative to the reference axis when the at least one comb is moved relative to the sheet material (or vice versa). By moving the alignment device and the sheet material relative to each other during the alignment of the elongated susceptor elements, the throughput of the method according to the present disclosure can be increased, thus allowing for the elongated susceptor elements to be at least partially aligned over a large portion of the sheet material. This is particularly advantageous when the sheet material is provided as a continuous substrate sheet. Preferably, the teeth of the at least one comb can be uniformly spaced along the row of teeth, meaning that the width of the inter-tooth spacing between adjacent teeth is the same for all teeth of the at least one comb.

[0007] As used herein, the term "elongated susceptor element" refers to a susceptor element having a greater extent in one principal dimension than in the two remaining dimensions perpendicular to the principal dimension. As such, an elongated susceptor element can also be denoted as a ID elongated susceptor element (synonym for one-dimensional elongated susceptor element) or quasi- ID susceptor element (synonym for quasi-one-dimensional susceptor element). In particular, the term "elongated susceptor element" can refer to a susceptor element whose length dimension is greater than any lateral dimension perpendicular to the length dimension. More particularly, a ID elongated susceptor element can be an elongate or oblong susceptor element.

[0008] As used herein, the term "width of the interdental space" refers to the smallest dimension of the space between adjacent teeth.

[0009] Although the present invention is described herein with respect to elongated susceptor elements whose length dimension is greater than any lateral dimension perpendicular to the length dimension (i.e., with respect to ID elongated susceptor elements having a greater extent in one principal dimension than in the two remaining dimensions perpendicular to the principal dimension), it is equally applicable to susceptor elements having a greater extent in two (perpendicular) principal dimensions than in the remaining dimension perpendicular to the principal dimensions. Such susceptor elements can also be denoted as 2D elongated susceptor elements. In particular, the present invention is equally applicable to susceptor elements whose length dimension and width dimension are greater than the thickness direction, wherein the length dimension can be greater than or substantially similar to the width dimension. More particularly, the present invention is equally applicable to susceptor elements having one of a oblong cylindrical shape (such as a coin shape), or an oblong elliptical shape (such as a lens shape), or a lamella shape or a plate shape. For these susceptor elements, the same features and advantages as described herein with respect to the (ID) elongated susceptor elements apply equally and can be stated equally by substantially replacing the term "maximum length dimension of the (ID) elongated susceptor element(s)" with "maximum extent of the 2D elongated susceptor element(s) in the two principal dimensions" and replacing "maximum lateral dimension of the (ID) elongated susceptor element(s)" with "maximum extent of the 2D elongated susceptor element(s) in the remaining (non-principal) dimension".

[0010] The use of multiple elongate susceptor elements dispersed throughout the aerosol-forming substrate advantageously results in a more uniform heat distribution across the substrate compared to a single solid susceptor element, without any significant temperature gradients across different substrate regions. Furthermore, in the case where the susceptor material of the susceptor elements has a high thermal conductivity, the uniformity of the heat distribution is further enhanced by the fact that a substrate including multiple susceptor elements dispersed therein exhibits an increased equivalent thermal conductivity compared to a substrate without susceptor elements or a substrate with only a single solid susceptor element. Moreover, the proposed susceptor arrangement is less sensitive to the positioning of the susceptor elements in achieving a uniform heat distribution compared to a single solid susceptor element.

[0011] Most importantly, it was found that the geometry, in particular the relative dimensions, of the susceptor elements have a significant impact on the heating efficiency and thus on the extraction efficiency of the substrate. In this regard, it was found that susceptor elements having an elongated shape are less susceptible to the demagnetization effect than comparably dimensioned 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, the susceptor element becomes gradually magnetized. With increasing external field, so does the internal magnetization. This process continues until the magnetization reaches the magnetic saturation point of the material, beyond which no further magnetization occurs. Thus, the magnetization of the susceptor element causes a build-up of magnetic charge density at the opposite ends of the susceptor element as seen in the direction of the external magnetic field. The susceptor element thus generates a magnetic field that causes a self-interaction with its material. This field is oriented in the same direction as the external magnetic field, but points in the opposite direction and is therefore referred to as the demagnetizing field. The demagnetizing field depends on the geometry of the susceptor element, but not on its absolute dimensions. Assuming that the susceptor element responds to a change in the external magnetic field, it is generally assumed that the demagnetizing field is proportional to the magnetization in each direction, which is related to a geometry-dependent proportionality constant referred to as the demagnetization factor. The demagnetization factor depends on the shape of the susceptor element as well as its relative orientation with respect to the external magnetic field. In this regard, it has been found that an external magnetic field produces a weaker or even negligible demagnetizing field for elongated susceptor elements, such as susceptor elements having the shape of a fiber or a thin rod, whose length dimension is significantly larger than any transverse dimension perpendicular to the length dimension, than for non-elongated (equi-dimensional) susceptor elements such as spherical or quasi-spherical susceptor elements. This can be intuitively understood because in a properly aligned elongated susceptor element, the build-up of magnetic charge density at the opposite ends of the susceptor element is spatially further apart from each other. This significantly reduces the demagnetizing field in its strength and thus its impact on the magnetization field that creates the power loss. Thus, for elongated susceptor elements, the power loss and thus the heating efficiency is greater than for non-elongated (equi-dimensional) susceptor elements such as spherical or quasi-spherical susceptor elements. This applies in particular to the case where the orientation of the magnetic field is substantially parallel to the length dimension of the elongated susceptor element, in which configuration the heating performance is at a maximum. However, it has been found that the elongated susceptor elements do not necessarily need to be aligned completely parallel to the direction of the external magnetic field. Even if the orientation of the susceptor elements with respect to the external magnetic field is aligned within a certain angular range, the overall heating performance is still higher than for susceptor devices having randomly oriented susceptor elements.

[0012] As mentioned above, the aerosol-forming substrate comprises a plurality of elongated susceptor elements. Preferably, the elongated susceptor elements can be deposited on the major surface of the sheet material prior to passing the elongated susceptor elements between the teeth of the at least one comb. In this particular case, the at least one comb can be arranged such that the free ends of the teeth of the at least one comb, meaning the ends of the teeth facing the sheet material, wipe the major surface of the sheet material to at least partially align the elongated susceptor elements passing between the teeth.

[0013] To increase the adhesion of the elongated susceptor elements to the major surface of the sheet material, an adhesive can be applied to the major surface of the sheet material. The adhesive can be applied prior to depositing the susceptor elements on the major surface of the sheet material. Alternatively, the adhesive can be applied to the major surface of the sheet material after at least partially aligning the elongated susceptor elements. Thus, the adhesive can advantageously avoid displacement of the at least partially aligned elongated susceptor elements during subsequent processing of the sheet material. Preferably, the adhesive comprises glycerol.

[0014] Alternatively or in addition to applying an adhesive, displacement of the elongated susceptor elements can also be avoided after at least partial alignment of the elongated susceptor elements by at least partially embedding the elongated susceptor elements into the sheet material, e.g. by means of a pressing device and / or a roller.

[0015] Alternatively or in addition, the elongated susceptor elements can be dispersed throughout the aerosol-forming substrate provided as a sheet material. In this case, the aerosol-forming substrate can be provided with a viscosity which allows the teeth of the at least one comb to be inserted into the sheet material such that the elongated susceptor elements dispersed in the sheet material can move when passing between the teeth of the at least one comb and are at least partially aligned. Preferably, after at least partially aligning the elongated susceptor elements, the aerosol-forming substrate is dried, hardened and / or cured in order to avoid displacement of the elongated susceptor elements during subsequent processing of the sheet material.

[0016] Since the overall heating performance of the elongated susceptor elements increases with decreasing deviation from an alignment substantially parallel to the alternating magnetic field for inductive heating, the elongated susceptor elements can preferably be aligned such that the angle between the length dimension of the elongated susceptor elements and the reference axis is in the range between +30 degrees and -30 degrees, preferably between +25 degrees and -25 degrees, in particular between +10 degrees and -10 degrees. Thus, an aerosol-forming substrate with improved heating performance can be provided. As used herein, the term “(at least) partially aligned” or “(at least) partially aligning” refers to such an alignment within the above-defined angular range.

[0017] As mentioned above, for a substantially parallel alignment, the heating performance is at a maximum. Therefore, the elongated susceptor elements are preferably aligned substantially parallel to the reference axis. As used herein, the term "substantially parallel" is understood as "parallel with a deviation of ± 5° from the parallel arrangement".

[0018] In general, the elongated susceptor elements can even be randomly oriented within the aerosol-forming substrate, although the overall heating performance is lower for a randomly oriented set of elongated susceptor elements compared to a set of elongated susceptor elements aligned at an angle within a certain angle range or substantially parallel to the alternating magnetic field. This is because the overall heating performance of a randomly oriented set of elongated susceptor elements is still higher than the overall heating performance of a set of non-elongated susceptor elements on a statistical average when considering the set of susceptor elements.

[0019] With the method (and device) according to the present disclosure, a method / device is provided which allows to easily at least partially align elongated susceptor elements deposited on a major surface of a sheet material and / or dispersed throughout an aerosol-forming substrate provided as a sheet material, thus allowing to manufacture an inductively heatable aerosol-generating article with improved heating performance.

[0020] Whenever in the present disclosure a number or a range is given for a plurality of objects, such as for a plurality of susceptor elements, this means that the number or range applies to at least 60%, in particular to at least 70%, more particularly to at least 80%, especially to at least 90% of all objects of the plurality of objects, preferably to all objects of the plurality of objects. For example, in case the present disclosure states that the elongated susceptor elements are aligned such that the angle between the length dimension of the elongated susceptor elements and the reference axis is within a range of +A degrees and -A degrees, this means that at least 60%, in particular at least 70%, more particularly at least 80%, especially at least 90% of all elongated susceptor elements are aligned such that the angle between the length dimension of the elongated susceptor elements and the reference axis is within a range of +A degrees and -A degrees.

[0021] In particular, during the alignment of the elongated susceptor elements, the sheet material can be moved continuously or stepwise in a transport direction relative to, in particular past, the alignment device. Preferably, the transport direction can be parallel to a plane defined by the sheet material or parallel to a plane tangential to the sheet material at the alignment position.

[0022] As used herein, the term "alignment position" refers to the current (surface) portion of the sheet material at which the elongated susceptor elements of the sheet material pass between the teeth of the at least one comb of the alignment device.

[0023] Preferably, the conveying direction can be substantially parallel to the reference axis of the sheet material. Thus, in particular by providing the sheet material as a continuous substrate sheet, it is possible to provide a sheet material having elongated susceptor elements which are at least partially aligned with respect to both the reference axis and the conveying direction, thereby allowing to improve the alignment performance when using the method according to the present disclosure.

[0024] Moving the sheet material continuously or stepwise in the conveying direction relative to, in particular past, the alignment device can be achieved by means of a substrate conveyor belt or one or more rollers.

[0025] Preferably, the alignment device can be arranged vertically above the sheet material at the alignment position.

[0026] As used herein, the term "vertically arranged above" is to be understood as being located above the plane of the sheet material, or in the projection of the plane tangential to the sheet material at the alignment position.

[0027] The alignment device can comprise a plurality of combs, wherein each comb can preferably have a different width of the tooth spacing, i.e. the lateral distance between adjacent teeth of the comb. The plurality of combs can be arranged in order of decreasing width of the tooth spacing along the reference axis of the sheet material.

[0028] By providing an alignment device comprising a plurality of combs, it is possible to further increase the at least partial alignment. The alignment device can comprise a plurality of combs having the same width of the tooth spacing. Alternatively, at least one comb of the plurality of combs can have a different width of the tooth spacing than the remaining combs, in particular a narrower width of the tooth spacing than the remaining combs. In particular, each comb can have a different width of the tooth spacing and be arranged such that its width of the tooth spacing decreases along the reference axis of the sheet material. This has proven to be particularly advantageous in case the plurality of combs is moved relative to the sheet material along the length extension of the alignment position, in particular along a travel direction opposite to the conveying direction of the sheet material, e.g. by means of a drive mechanism, such that the plurality of combs lifts off from the sheet material as the sheet material exits the alignment position. Thus, it is possible to reduce and / or avoid accumulation of elongated susceptor elements upstream of the combs and clogging of the combs. This is even more preferred when at least one comb of the plurality of combs has a different width of the tooth spacing than the remaining combs.

[0029] Thus, when the alignment device and the sheet material are moved relative to each other, the elongated susceptor elements can first pass between the widely spaced teeth of the first comb, then between the teeth of the second comb, whereby the width of the spacing of the teeth of the second comb can be smaller than the width of the spacing of the teeth of the first comb. Likewise, the elongated susceptor elements can then pass between the teeth of a third comb, a fourth comb, etc., until a desired at least partial alignment of the elongated susceptor elements relative to the reference axis is achieved. After passing between the teeth of the first comb, at least a partial alignment of the elongated susceptor elements can already be achieved, wherein further sequentially arranged combs can be used to further increase the at least partial alignment of the elongated susceptor elements. Alternatively, at least the first comb can be used to roughly orient the elongated susceptor elements relative to the reference axis, and one or more of the further sequentially arranged combs can be used to at least partially align the elongated susceptor elements.

[0030] The teeth of the at least one comb can be pre-stressed, in particular in a direction substantially parallel to the reference axis. The pre-stressing of the teeth can be achieved by providing a comb with flexible teeth or by configuring the teeth of the comb or the comb itself to be mechanically pre-stressed. Thereby preferably the teeth of the at least one comb are configured such that upon application of a force above a given threshold the pre-stress is overcome and thus the teeth can be flexed and / or moved by the applied force (and against the pre-stress). Accumulation of elongated susceptor elements upstream of the comb and / or clogging of the comb can thus be avoided, since it has been shown that the force applied to the teeth of the comb increases when elongated susceptor elements accumulate upstream of the comb, in particular due to clogging of the spaces between the teeth of the comb. Preferably, in an arrangement with pre-stressed teeth the alignment device comprises at least two sequentially arranged combs with the same width of the spacing of the teeth to ensure that the elongated susceptor elements also pass between the teeth of the combs in case of accumulation and / or clogging.

[0031] An additional or alternative measure to avoid accumulation of elongated susceptor elements upstream of the at least one comb and / or clogging of the spaces between the teeth of the at least one comb can be to provide a vibration generation for vibrating the at least one comb.

[0032] To align the elongated susceptor elements over the entire width of the sheet material, the alignment device can be configured such that the lateral dimension of the at least one comb substantially corresponds to the lateral dimension of the sheet material.

[0033] Preferably, the aerosol-forming substrate can be made from a substrate slurry cast into the form of a sheet material, wherein, in particular prior to drying the cast substrate slurry, elongated susceptor elements can be deposited on a major surface of the sheet material and / or can be dispersed throughout the sheet material. Depending on the firmness of the cast substrate slurry, the elongated susceptor elements can be at least partially embedded within the substrate sheet prior to the alignment step, after or during deposition.

[0034] As already mentioned above, the aerosol-forming substrate in the form of a sheet material can be a continuous substrate sheet, thus enabling a continuous alignment of elongated susceptor elements on / in the continuous substrate sheet and increasing the throughput of the method according to the present disclosure.

[0035] As discussed above, the geometry, in particular the relative dimensions, of the elongated susceptor elements have a significant impact on the heating efficiency and thus on the extraction efficiency of the substrate. Thus, the elongated susceptor elements can be selected such as to have a ratio of the length dimension to the maximum transversal dimension of greater than 4, in particular greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, most preferably greater than 35. As used herein, the term "maximum transversal dimension" refers to the maximum dimension of the elongated susceptor element perpendicular to the main dimension (length dimension). This ratio can also be expressed as aspect ratio or shape factor.

[0036] As used herein, the ratio of the maximum length dimension of the elongated susceptor element to the maximum transversal dimension of the elongated susceptor element perpendicular to the length dimension is also expressed as shape factor or aspect ratio. Thus, 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, most preferably greater than 35.

[0037] Preferably, the ratio of the maximum length dimension to the maximum transversal dimension (shape factor) not only has a lower limit but also an upper limit. Thus, the ratio of the maximum length dimension to the maximum transversal dimension perpendicular to the (maximum) length dimension of the elongated susceptor element (i.e. the shape factor of the elongated susceptor element) can be in the range between 4 and 500, in particular between 10 and 300, preferably between 20 and 200, more preferably between 30 and 100.

[0038] In absolute terms, the length dimension of the elongated susceptor element can be in the range between 20 micrometers and 50 millimeters, in particular between 100 micrometers and 16 millimeters, preferably between 0.5 millimeters and 5 millimeters. Such maximum length dimensions prove to be advantageous in the alignment aspect according to the present disclosure.

[0039] The respective absolute value of the maximum transversal dimension of the elongated susceptor element is preferably chosen such that the form factor is above the lower limit defined above, advantageously also within the preferred range defined above, depending on the respective absolute value of the maximum length dimension. Thus, the maximum transversal dimension of the elongated susceptor element can be in the range between 5 micrometer and 500 micrometer, in particular between 10 micrometer and 150 micrometer, preferably between 80 micrometer and 120 micrometer. In particular, the maximum transversal dimension of the elongated susceptor element can be equal to or less than 500 micrometer, in particular equal to or less than 100 micrometer, preferably equal to or less than 50 micrometer, more preferably equal to or less than 25 micrometer.

[0040] To provide an efficient alignment of the elongated susceptor elements, the at least one comb can be configured to have a width of the tooth spacing in the range between 1 times and 5 times, in particular between 1 times and 3 times, more in particular between 1 times and 2 times, the maximum transversal dimension of the elongated susceptor elements. In terms of absolute values, the at least one comb can be configured to have a width of the tooth spacing in the range between 5 micrometer and 1000 micrometer, in particular between 5 micrometer and 500 micrometer or between 5 micrometer and 300 micrometer, more in particular between 5 micrometer and 150 micrometer, preferably between 10 micrometer and 120 micrometer or between 80 micrometer and 120 micrometer or between 20 micrometer and 240 micrometer or between 80 micrometer and 240 micrometer. Likewise, the at least one comb can be configured to have a width of the tooth spacing equal to or less than 1000 micrometer, in particular equal to or less than 500 micrometer, more in particular equal to or less than 200 micrometer, preferably equal to or less than 100 micrometer, more preferably equal to or less than 50 micrometer or 25 micrometer.

[0041] The heating efficiency also depends on the density of the elongated susceptor elements within the aerosol-forming substrate. The higher the density, the higher the heating efficiency. Preferably, the (volume) density of the elongated susceptor elements within the aerosol-forming substrate is in the range between 0.001 susceptor elements per cubic millimeter and 30 susceptor elements per cubic millimeter, in particular between 0.1 susceptor elements per cubic millimeter and 10 susceptor elements per cubic millimeter. Likewise, the mass density of the elongated susceptor elements within the aerosol-forming substrate can be in the range between 0.002 milligram susceptor mass per cubic millimeter and 0.3 milligram susceptor mass per cubic millimeter, in particular between 0.01 milligram susceptor mass per cubic millimeter and 0.1 milligram susceptor mass per cubic millimeter.

[0042] In general, the susceptor elements can have any geometry as long as they are elongated. In particular, the elongated susceptor elements can have one of a cylindrical shape or an oblong elliptical shape. That is, the elongated susceptor elements can have a strip-like shape or a granular shape.

[0043] As an example, the elongated susceptor element can be a fiber element, in particular a chopped fiber element or a ground fiber element. As another example, the elongated susceptor element can be a filament element or a thread element or a granule element or a strip element. Advantageously, the fiber element or the filament element or the thread element or the granule element or the filament element or the strip element is made of a material that can be inductively heated, such as metal fibers or metal filaments or metal threads that are readily available at low cost.

[0044] As seen in a plane perpendicular to the length dimension of the elongated susceptor element, the cross section of the elongated susceptor element can have a circular shape or an oval shape or an elliptical shape or a triangular shape or a rectangular shape or a quadric surface shape or a polygonal shape. If the cross section is circular, the above-mentioned maximum transverse dimension of the elongated susceptor element corresponds to the diameter of the susceptor element, wherein this diameter is at maximum along the length dimension of the elongated susceptor element. If the cross section is oval or elliptical, the above-mentioned maximum transverse dimension of the susceptor element corresponds to the length of the semi-major axis of the oval or elliptical cross section, wherein this length is at maximum along the length dimension of the elongated susceptor element. If the cross section is a quadric surface or generally rectangular, the above-mentioned maximum transverse dimension of the susceptor element corresponds to the length of the edge / main edge of the quadric surface / rectangular cross section.

[0045] Generally, the term "susceptor element" as used herein refers to an element comprising a susceptor material that is capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This can be the result of at least one of magnetic hysteresis losses and eddy currents induced in the susceptor material, depending on the electrical and magnetic properties of the susceptor material. In ferromagnetic or ferrimagnetic susceptor materials, magnetic hysteresis losses occur due to the switching of magnetic domains within the material under the influence of an alternating electromagnetic field. If the susceptor material is electrically conductive, eddy currents can be induced. In the case of an electrically conductive ferromagnetic or ferrimagnetic susceptor, heat can be generated due to both eddy currents and magnetic hysteresis losses.

[0046] Thus, the elongated susceptor element can generally be at least one of electrically conductive and ferromagnetic or ferrimagnetic. In particular, the susceptor material of the elongated susceptor element can be non-conductive, but ferromagnetic or ferrimagnetic. Alternatively, the susceptor material of the elongated susceptor element can be electrically conductive, but neither ferromagnetic nor ferrimagnetic.

[0047] Preferably, the susceptor material of the elongated susceptor element can comprise or consist of a metal, such as ferritic iron, or a stainless steel, in particular a 410-grade, 420-grade or 430-grade stainless steel, or a ferrimagnetic ceramic.

[0048] In addition to the susceptor material, the elongated susceptor element can comprise a ferromagnetic or ferrimagnetic temperature marker material.

[0049] While the susceptor material is optimized in terms of heat loss and thus heating efficiency, the temperature marker material is a magnetic (ferromagnetic or ferrimagnetic) material chosen so as to have a Curie temperature substantially corresponding to a predefined temperature point of the heating process.

[0050] The temperature marker material can have a Curie temperature below 500°C, preferably equal to or below 400°C, in particular equal to or below 390°C. For example, the temperature marker material of the elongated susceptor element can have a Curie temperature in the range between 180°C and 420°C, in particular between 210°C and 380°C, preferably between 250°C and 380°C. While the temperature marker material is a functional material that provides the temperature marker functionality mainly by its Curie temperature, it can also influence the inductive heating process of the susceptor device.

[0051] The temperature marker material of the elongated susceptor element can comprise or can consist of nickel or a nickel alloy.

[0052] The susceptor element can be formed such that the susceptor material is at least partially, preferably completely, surrounded or covered by the temperature marker material.

[0053] In addition, the elongated susceptor element can comprise an outer protective coating that surrounds the susceptor material and, if present, the temperature marker material. Preferably, the protective coating renders the elongated susceptor element resistant to external influences, in particular corrosive influences.

[0054] The provided elongated susceptor elements can have substantially the same properties, such as susceptor material, maximum range, shape ratio, temperature marker material, outer coating, etc. Alternatively, a mixture of elongated susceptor elements with different properties can be provided.

[0055] It is also possible that the susceptor material of the susceptor element itself has a temperature marker functionality. That is, the elongated susceptor element can comprise a single material that acts both as susceptor material and as temperature marker material.

[0056] The present disclosure also relates to an apparatus for aligning elongated susceptor elements in / on an aerosol-forming substrate. The apparatus can in particular be suitable for use in a method according to the present disclosure. Accordingly, the above description applies accordingly to the apparatus according to the present disclosure.

[0057] The apparatus can comprise an alignment device comprising at least one comb having a plurality of teeth arranged in a row. The aerosol-forming substrate comprising the elongated susceptor elements is provided to the apparatus as a sheet material. The alignment device and the sheet material are moved relative to each other such that the elongated susceptor elements passing between the teeth of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

[0058] Preferably, the elongated susceptor elements can be provided and supplied to the aerosol-forming substrate via a susceptor supply upstream of the alignment device. In particular, the susceptor supply can be a hopper.

[0059] Preferably, the aerosol-forming substrate in the form of a sheet material can be provided to or past the alignment device via a substrate supply. Preferably, the substrate supply can be configured to provide the sheet material vertically below the alignment device.

[0060] The substrate supply can preferably comprise a conveyor belt or one or more rollers for continuously or stepwise providing the aerosol-forming substrate in the form of a sheet material in a conveying direction to and / or past the alignment device. Preferably, the conveying direction can be parallel to a plane defined by the sheet material or parallel to a plane tangential to the sheet material at the alignment position.

[0061] The alignment device can preferably comprise a plurality of combs, wherein each comb preferably has a different width of the tooth spacing, and wherein the plurality of combs can be arranged along the reference axis of the sheet material in order of decreasing width of the tooth spacing.

[0062] In particular in a direction substantially parallel to the reference axis of the sheet material, the teeth of at least one comb can preferably be pre-stressed for counteracting an accumulation of elongated susceptor elements upstream of the at least one comb, in particular due to an accumulation of blockages.

[0063] As an alternative or additional feature for avoiding and / or reducing an accumulation of elongated susceptor elements upstream of at least one comb, the apparatus can preferably further comprise a vibration generator for vibrating the at least one comb.

[0064] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate capable of releasing volatile compounds upon being heated so as to form an aerosol. The aerosol-generating article can be a consumable, in particular a consumable which is discarded after a single use. For example, the article can be an elongated article or a rod-shaped article. The elongated or rod-shaped article can have a shape similar to the shape of a conventional cigarette. In particular, such an article can have a circular or elliptical or oval or square or rectangular or triangular or polygonal cross-section.

[0065] As used herein, the term "aerosol-forming substrate" denotes a substrate formed from or comprising aerosol-forming material, which is capable of releasing volatile compounds upon heating in order to generate an aerosol. Preferably, the aerosol-forming substrate is intended to be heated rather than combusted in order to release the volatile compounds forming the aerosol. Thus, such a substrate can be denoted as a heat-not-burn aerosol-forming substrate. Likewise, an aerosol-generating article comprising such an aerosol-forming substrate can be denoted as a heat-not-burn aerosol-generating article.

[0066] Generally, the aerosol-forming substrate can comprise at least one aerosol-forming agent and at least one sensate material, both of which are volatile upon being heated. The sensate material can comprise at least one of a tobacco-containing material, a nicotine-containing material, and a flavouring substance. Examples of suitable aerosol-forming agents are glycerol and propylene glycol. Examples of flavouring substances can be plant extracts and natural or artificial flavourings.

[0067] The aerosol-forming substrate can be a solid aerosol-forming substrate, a gel-like aerosol-forming substrate, or any combination thereof.

[0068] As mentioned above, the aerosol-forming substrate can comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. In particular, the aerosol-forming substrate can comprise a reconstituted tobacco material or a tobacco-containing pulp. Thus, the aerosol-generating article can be a tobacco-containing article. Alternatively or additionally, the aerosol-forming substrate can comprise a non-tobacco material. The aerosol-forming substrate can further comprise other additives and ingredients, such as nicotine or a flavourant.

[0069] The aerosol-forming substrate can also be a paste-like material, a small pouch of porous material comprising the aerosol-forming substrate, or loose tobacco, for example mixed with a gelling or binding agent, which can comprise a common aerosol-forming agent such as glycerol and which is compressed or moulded into a rod.

[0070] The aerosol-forming substrate is made from a sheet material. For example, the aerosol-forming substrate can be made from a crimped tobacco sheet comprising a tobacco material, organic fibres, a binder, an aerosol-forming agent. Alternatively, the aerosol-forming substrate can be made from a sheet material comprising a nicotine-containing material, organic fibres, a binder, an aerosol-forming agent. As yet another alternative, the aerosol-forming substrate can be made from a sheet material containing a cut filler of tobacco. In this regard, it has been found that if the elongated susceptor elements are applied to the aerosol-forming substrate and aligned while the aerosol-forming substrate is in the form of a sheet material, the aerosol-generating article is easy to manufacture, especially in terms of the preferred alignment of the elongated susceptor elements relative to a predefined reference axis of the article. This can be a result of the manufacturing process, which comprises depositing the elongated susceptor elements on an outer surface of the sheet material and / or dispersing the elongated susceptor elements within the sheet material during a primary process, in which the sheet material is produced, or during a secondary process, in which the sheet material is machined and combined with other semi-finished products to obtain the final product, if the elongated susceptor elements are deposited on a major surface of the sheet material. Thus, the elongated susceptor elements can end up on an outer surface of the sheet material, at least partially embedded in the sheet material close to an outer surface of the sheet material, or dispersed throughout the sheet material, in a manner at least partially aligned with each other and with the reference axis of the sheet material. This can be observed even if the sheet material is subsequently machined, for example crimped and gathered, in order to form a substrate rod in the final article.

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

[0072] Example Ex1 : A method of aligning elongated susceptor elements in an aerosol-forming substrate for use in an inductively heatable aerosol-generating article, the method comprising the steps of: providing an aerosol-forming substrate in the form of a sheet material to an alignment device, the aerosol-forming substrate comprising a plurality of elongated susceptor elements, the alignment device comprising at least one comb having a plurality of teeth arranged in a row; and moving the alignment device and the sheet material relative to each other such that the elongated susceptor elements passing between the teeth of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

[0073] Example Ex2: The method according to example Ex1, wherein the elongated susceptor elements are deposited on a major surface of the sheet material.

[0074] Example Ex3: The method according to Example Ex1 or Ex2, wherein an adhesive is applied to the major surface of the sheet material before or after depositing the susceptor elements on the major surface of the sheet material.

[0075] Example Ex4: The method according to Example Ex3, wherein the adhesive comprises glycerol.

[0076] Example Ex5: The method according to Example Ex1, wherein the elongated susceptor elements are dispersed throughout the aerosol-forming substrate provided as a sheet material.

[0077] Example Ex6: The method according to any one of the preceding examples, wherein the elongated susceptor elements are at least partially aligned such that an angle between a length dimension of the elongated susceptor elements and the reference axis is in a range between +30 degrees and -30 degrees, preferably between +25 degrees and -25 degrees, in particular between +10 degrees and -10 degrees.

[0078] Example Ex7: The method according to any one of the preceding examples, wherein the elongated susceptor elements are aligned substantially parallel to each other and parallel to the reference axis.

[0079] Example Ex8: The method according to any one of the preceding examples, wherein during the alignment of the elongated susceptor elements, the sheet material is moved relative to, in particular past, the alignment device in a conveying direction, the conveying direction being preferably parallel to a plane defined by the sheet material or parallel to a plane tangential to the sheet material at the alignment position.

[0080] Example Ex9: The method according to Example Ex8, wherein the conveying direction is substantially parallel to the reference axis.

[0081] Example Ex10: The method according to any one of Examples Ex8 or Ex9, wherein the sheet material is moved relative to, in particular past, the alignment device in the conveying direction by means of a substrate conveyor belt or by means of one or more rollers.

[0082] Example Ex11 : The method according to any one of the preceding examples, wherein the alignment device is arranged vertically above the sheet material at the alignment position.

[0083] Example Ex12: The method according to any one of the preceding examples, wherein the alignment device comprises a plurality of combs, wherein each comb preferably has a different width of tooth spacing, and wherein the plurality of combs are arranged along the reference axis of the sheet material in an order of decreasing width of tooth spacing.

[0084] Example Ex13: A method according to any of the preceding examples, wherein the teeth of the at least one comb are pre-stressed, in particular in a direction substantially parallel to a reference axis of the sheet material.

[0085] Example Ex14: A method according to any of the preceding examples, wherein the at least one comb is vibrated by means of a vibration generator.

[0086] Example Ex15: A method according to any of the preceding examples, wherein the lateral dimension of the at least one comb substantially corresponds to the lateral dimension of the sheet material.

[0087] Example Ex16: A method according to any of the preceding examples, wherein the aerosol-forming substrate is made from a substrate slurry cast into the form of the sheet material.

[0088] Example Ex17: A method according to Example Ex16, wherein the elongate susceptor element is deposited on a major surface of the sheet material or dispersed throughout the sheet material prior to drying the cast substrate slurry.

[0089] Example Ex18: A method according to any of the preceding examples, wherein the aerosol-forming substrate in the form of the sheet material is a continuous substrate sheet.

[0090] Example Ex19: A method according to any of the preceding examples, wherein the ratio of the length dimension to the maximum transverse dimension of the elongate 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, most preferably greater than 35.

[0091] Example Ex20: A method according to any of the preceding examples, wherein the ratio of the length dimension to the maximum transverse dimension of the elongate susceptor element is in the range between 4 and 500, in particular between 10 and 300, preferably between 20 and 200, more preferably between 30 and 100.

[0092] Example Ex21 : A method according to any of the preceding examples, wherein the length dimension of the elongate susceptor element is in the range between 20 micrometres and 50 millimetres, in particular between 100 micrometres and 16 millimetres, preferably between 0.5 millimetres and 5 millimetres.

[0093] Example Ex22: A method according to any of the preceding examples, wherein the maximum transverse dimension of the elongate susceptor element is in the range between 5 micrometres and 500 micrometres, in particular between 10 micrometres and 150 micrometres, preferably between 80 micrometres and 120 micrometres.

[0094] Example Ex23: The method according to any one of the preceding examples, wherein the elongated susceptor element has a maximum lateral dimension equal to or less than 500 micrometers, in particular equal to or less than 100 micrometers, preferably equal to or less than 50 micrometers, more preferably equal to or less than 25 micrometers.

[0095] Example Ex24: The method according to any one of the preceding examples, wherein the elongated susceptor element has one of a cylindrical shape or an oblong elliptical shape.

[0096] Example Ex25: The method according to any one of the preceding examples, wherein the elongated susceptor element is one of a fiber element, or a filament element, or a thread element, or a particle element, or a strip element, the fiber element in particular being a chopped fiber element or a milled fiber element.

[0097] Example Ex26: The method according to any one of the preceding examples, wherein a cross-section of the elongated susceptor element in a plane perpendicular to a length dimension of the susceptor element has a circular shape or an oval shape or an elliptical shape or a triangular shape or a rectangular shape or a quadric surface shape or a polygonal shape.

[0098] Example Ex27: The method according to any one of the preceding examples, wherein the elongated susceptor element comprises a susceptor material, the susceptor material being at least one of electrically conductive, and ferromagnetic or ferrimagnetic.

[0099] Example Ex28: The method according to example Ex27, wherein the susceptor material of the elongated susceptor element comprises or consists of a metal or a ferrimagnetic ceramic, the metal being for example ferritic iron, or a stainless steel, in particular a 410-grade, 420-grade or 430-grade stainless steel.

[0100] Example Ex29: The method according to any one of examples Ex27 or Ex28, wherein the elongated susceptor element comprises, in addition to the susceptor material, a ferromagnetic or ferrimagnetic temperature marker material.

[0101] Example Ex30: The method according to example Ex29, wherein the temperature marker material of the elongated susceptor element comprises or consists of nickel or a nickel alloy.

[0102] Example Ex31 : The method according to any one of the preceding examples, wherein the at least one comb is configured to have a width of the tooth spacing in a range between 1 times and 5 times, in particular between 1 times and 3 times, more particularly between 1 times and 2 times, of a maximum lateral dimension of the elongated susceptor element.

[0103] Example Ex32: The method according to any of the preceding examples, wherein the at least one comb is configurable to have a width of the tooth spacing in a range between 5 micrometers and 1000 micrometers, in particular between 5 micrometers and 500 micrometers or between 5 micrometers and 300 micrometers, more particularly between 5 micrometers and 150 micrometers, preferably between 10 micrometers and 120 micrometers or between 80 micrometers and 120 micrometers or between 20 micrometers and 240 micrometers or between 80 micrometers and 240 micrometers.

[0104] Example Ex33: The method according to any of the preceding examples, wherein the at least one comb is configurable to have a width of the tooth spacing equal to or less than 1000 micrometers, in particular equal to or less than 500 micrometers, more particularly equal to or less than 200 micrometers, preferably equal to or less than 100 micrometers, more preferably equal to or less than 50 micrometers or 25 micrometers.

[0105] Example Ex34: An apparatus for aligning elongated susceptor elements in / on an aerosol- forming substrate, in particular for use in a method according to any of the preceding examples, the apparatus comprising an alignment device comprising at least one comb having a plurality of teeth arranged in a row, wherein an aerosol-forming substrate comprising elongated susceptor elements is provided to the apparatus as a sheet material, wherein the alignment device and the sheet material are moved relative to each other such that the elongated susceptor elements passing between the teeth of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

[0106] Example Ex35: The apparatus according to example Ex34, further comprising a susceptor supply configured for providing and supplying elongated susceptor elements to the aerosol-forming substrate upstream of the alignment device.

[0107] Example Ex36: The apparatus according to any of examples Ex34 or Ex35, further comprising a substrate supply for providing the aerosol-forming substrate in the form of a sheet material to or past the alignment device, in particular vertically below the alignment device.

[0108] Example Ex37: The apparatus according to example Ex36, wherein the substrate supply comprises a substrate conveyor belt or one or more rollers for providing the aerosol-forming substrate in the form of a sheet material to or past the alignment device in a conveying direction.

[0109] Example Ex38: The apparatus according to any one of the preceding examples Ex34 to Ex37, wherein the alignment device comprises a plurality of combs, wherein each comb preferably has a different width of the inter-dental spacing, and wherein the plurality of combs are arranged along the reference axis of the sheet material in order of decreasing width of the inter-dental spacing.

[0110] Example Ex39: The apparatus according to any one of the preceding examples Ex34 to Ex38, wherein the teeth of the at least one comb are pre-stressed, in particular in a direction substantially parallel to the reference axis of the sheet material.

[0111] Example Ex39: The apparatus according to any one of the preceding examples Ex34 to Ex39, wherein the apparatus further comprises a vibration generator for vibrating the at least one comb. BRIEF DESCRIPTION OF DRAWINGS

[0112] Examples will now be further described with reference to the drawings in which:

[0113] Figure 1A An alignment device according to the present application is schematically illustrated in top view;

[0114] Figure 1B Details of an aligned elongate susceptor element are schematically illustrated;

[0115] Figure 1C Details of a partially aligned elongate susceptor element are schematically illustrated;

[0116] Figure 2 An alignment device according to another embodiment of the present application is schematically illustrated in top view;

[0117] Figure 3 An alignment device according to the present application is schematically illustrated in side view;

[0118] Figure 4A A comb device according to the present application is schematically illustrated;

[0119] Figure 4B A comb device according to another embodiment of the present application is schematically illustrated;

[0120] Figure 5 An alignment device according to another embodiment of the present application is schematically illustrated in side view;

[0121] Figure 6 A flowchart of a method according to the present application is schematically illustrated; and

[0122] Figure 7 A substrate element comprising an elongate susceptor element is schematically and in detail illustrated.

[0123] All instances shown in the figures are schematic and not drawn to scale. DETAILED DESCRIPTION

[0124] In Figure 1A , an instance of the alignment device 1 is shown schematically in a top view. The susceptor supply 2 is arranged upstream of the alignment arrangement comprising the comb 5 to provide the elongated susceptor elements 3 to the aerosol-forming substrate provided as a sheet material 4. In Figure 4A , the comb 5 is shown schematically. The comb 5 comprises a plurality of teeth 6 arranged in a row, whereby a plurality of tooth spacings T is defined between adjacent teeth 6 of the comb 5, and each tooth 6 has a free end 7. The comb 5 is arranged vertically above the sheet material 5, in Figure 1A , in a top view above the plane of the sheet material 4. For the sake of clarity, in the instance shown in Figure 1A , the elongated susceptor elements 3 are shown as deposited on the major surface of the sheet material 4, but according to other possible instances, the elongated susceptor elements 3 can be dispersed throughout the aerosol-forming substrate provided as the sheet material 4. The sheet material 4 is conveyed in the conveying direction C by means of the susceptor supply, which will be described in more detail later.

[0125] As shown in Figure 4A , the comb 5 is arranged such that the free ends 7 of the teeth 6 of the comb 5 contact the major surface of the sheet material 4. Alternatively, as shown in Figure 4B , in case the elongated susceptor elements 3 are dispersed throughout the aerosol-forming substrate provided as the sheet material, the free ends 7 of the teeth 6 of the comb 5 can be arranged below the major surface of the sheet material 4. As the sheet material 4 is conveyed in the conveying direction C and the elongated susceptor elements 3 move along with the sheet material, the elongated susceptor elements 3 pass between the teeth 6 of the comb 6, wherein depending on the original orientation of the elongated susceptor elements, they can pass without contacting the teeth 6 of the comb 5, or they can contact the teeth 6 of the comb 5, whereby they are reoriented. The width of the tooth spacing T is chosen such that the elongated susceptor elements 3 passing between the teeth 6 of the comb 5 are at least partially aligned with respect to the reference axis R of the sheet material 4. In the instance shown in Figure 1A , the elongated susceptor elements 3 are conveyed from left to right along the conveying direction C. Thus, the elongated susceptor elements 3 on the right side of Figure 1A are aligned substantially parallel to each other and also substantially parallel to the reference axis R of the sheet material 4, in contrast to the elongated susceptor elements 3 on the left side of Figure 1A , which have passed between the teeth 6 of the comb 5. Figure 1BAs shown in more detail, the reference axis R is parallel to the conveying direction C. In this case, the elongated susceptor element 3 can also be aligned in an at least partially aligned manner with the projection of the elongated susceptor element 3 on the plane tangential to the sheet material 4 at the alignment position substantially parallel to the conveying direction C.

[0126] Alternatively, as shown in more detail in Figure 1C , the elongated susceptor element 3 can be aligned in an at least partially aligned manner, wherein the angle alpha (a) between the length dimension of the elongated susceptor element 3 and the reference axis R parallel to the conveying direction C is in the range between +30 degrees and -30 degrees, in particular between +25 degrees and -25 degrees, preferably between +10 degrees and -10 degrees. Thus, the elongated susceptor element 3 can be aligned in an at least partially aligned manner with the projection of the elongated susceptor element 3 on the plane tangential to the sheet material 4 at the alignment position and the conveying direction C.

[0127] Figure 2 Another example of an alignment device 1 is schematically shown in a top view. Figure 2 The alignment device 1 shown in Figure 1A corresponds essentially to the alignment device 1 shown in Figure 2 , with the difference that the alignment means comprise a plurality of combs, in the example shown in Figure 2 three combs 5, 5', 5''. The combs 5, 5' and 5'' are arranged in sequence along the conveying direction C and thus along the reference axis R of the sheet material 4. The width of the tooth spacing T of the comb 5 is greater than the width of the tooth spacing T of the comb 5'. Likewise, the width of the tooth spacing T of the comb 5' is greater than the width of the tooth spacing T of the comb 5''. Thus, the elongated susceptor element 3 is conveyed along with the sheet material 4 in the conveying direction C and first passes between the teeth 6 of the comb 5, then between the teeth 6 of the comb 5' and finally between the teeth of the comb 5''. Since the width of the tooth spacing T decreases along the conveying direction C, the elongated susceptor element 3 is aligned to a greater extent with each passage between the teeth 6 of the combs 5, 5' and 5'', respectively, until the desired at least partial alignment (in the case shown in Figure 1C , a substantially parallel alignment to each other and parallel alignment to the reference axis R) has been achieved. In other words, the angle alpha (a) between the length dimension of the elongated susceptor element 3 and the reference axis R (as shown in decreases with each passage between the teeth 6 of the combs 5, 5' and 5''. The combs 5, 5' and 5'' do not necessarily need to have different widths of the tooth spacing T. As an example, the combs 5 and 5' can have the same width of the tooth spacing T which is greater than the width of the tooth spacing T of the comb 5''. Likewise, the combs 5' and 5'' can have the same width of the tooth spacing T which is smaller than the width of the tooth spacing T of the comb 5.

[0128] Figure 3 InIn Fig. 1 a schematic simplified side view of an alignment device 1 according to the present application and comprising a substrate supply as mentioned above is shown. The sheet material 4 is conveyed in a conveying direction C parallel to a plane defined by the sheet material 4. The sheet material 4 can be conveyed in the conveying direction C continuously or stepwise by means of one or more rollers 8 and / or one or more conveyor belts 9. The combs 5 are arranged vertically above the sheet material 4 as shown in Figure 4A Fig. 2, such that the free ends 7 of the teeth 6 of the combs 5 contact the main surface of the sheet material, but can also be arranged with the free ends 7 of the teeth 6 of the combs 5 below the main surface of the sheet material 4 as shown in Figure 4B Fig. 3. In Fig. 4 a schematic simplified side view of another embodiment of an alignment device 1 according to the present application is shown. The substrate supply corresponds to the substrate supply as shown in Fig. 1 and can comprise one or more rollers 8 and / or one or more conveyor belts 9. The alignment device comprises a plurality of combs 5 arranged on a drive mechanism 10 for moving the combs 5 relative to the sheet material 4. During alignment of the elongated susceptor element 3, meaning when the free ends 7 of the teeth 6 are arranged at the alignment position as shown in

[0129] Fig. 5, the combs 5 are moved relative to the sheet material 4 along a travel direction D which can be opposite to the conveying direction C of the sheet material 4. As explained with respect to the alignment device of Figure 5 Fig. 6, the plurality of combs 5 can have the same width of the tooth spacing T or can have different widths of the tooth spacing T. For example, the plurality of combs can be a sequential arrangement of combs 5, 5' and 5'' followed by another sequential arrangement of the same sequence 5, 5' and 5''. As another example, the combs can be arranged alternatingly with a comb 5 arranged between two combs 5' and vice versa. Figure 3 Figure 4A Figure 4B Figure 2

[0130] Figure 5 ​​​The alignment device 1 can be configured such that the sheet material 4 is conveyed stepwise while the drive mechanism 10 can be operated continuously. The elongated susceptor elements 3 located at the alignment position are at least partially aligned by passing between the teeth 6 of the comb 5. After alignment, the sheet material 4 is conveyed in the conveying direction until the at least partially aligned elongated susceptor elements 3 are outside the alignment position and the conveying of the sheet material 4 is stopped, wherein a next portion of the sheet material 4 is subjected to the moving comb 5 to at least partially align the elongated susceptor elements 3. Then, the process is repeated. Preferably, however, the alignment device 1 is configured such that the sheet material 4, preferably a continuous substrate sheet, is continuously conveyed in the conveying direction C past the comb 5 at which the elongated susceptor elements 3 are at least partially aligned. This embodiment has the advantage that clogging of the comb 5 can be avoided since the comb 5 lifts off the sheet material when the sheet material moves outside the alignment position, in particular when the alignment means comprise multiple combs having different widths of the teeth spacing T.

[0131] In Figure 6 In the following, a flow chart of the method according to the present application is shown. The method of aligning elongated susceptor elements in an aerosol-forming substrate can be performed with the alignment device 1 according to the present application as described above. In a first step 20, an aerosol-forming substrate is provided in the form of a sheet material 4, wherein the aerosol-forming substrate comprises elongated susceptor elements 3 deposited on a main surface of the sheet material 4 and / or dispersed throughout the aerosol-forming substrate provided as sheet material 4. In step 20, the sheet material 4 comprising the elongated susceptor elements 3 is provided to an alignment means comprising at least one comb 5 having a plurality of teeth 6 arranged in a row. In a second step 21, the sheet material 4 comprising the elongated susceptor elements 3 is moved relative to the alignment means such that the elongated susceptor elements 3 passing between the teeth 6 of the at least one comb 5 are at least partially aligned relative to a reference axis R of the sheet material 4.

[0132] Figure 7A perspective view showing a portion of a substrate element 110 forming a portion of a rod-shaped aerosol-generating article, including a detailed view of its internal structure, in particular of the structure of the aerosol-forming substrate and the elongated susceptor elements 3 (lower right). As can be seen from both the perspective view and the detailed view, the aerosol-forming substrate is made of a sheet material 4 which has been gathered into the cylindrical shape of the substrate element 110 after aligning the elongated susceptor elements 3. For example, the aerosol-forming substrate 4 can be made of a crimped tobacco sheet comprising a tobacco material, organic fibers, a binder, aerosol. As can be further seen from the detailed view, at least some of the elongated susceptor elements 3 can be observed even though the sheet material 4 is crimped and gathered. According to the present invention, this can be a result of a manufacturing process comprising depositing the elongated susceptor elements 3 on a major surface of the sheet material 4 and subsequently at least partially aligning the elongated susceptor elements 3 during a primary process in which the sheet material 4 is produced or during a secondary process in which the sheet material 4 is machined, and / or dispersing the elongated susceptor elements 3 throughout the aerosol-forming substrate provided as sheet material 4 and subsequently at least partially aligning the elongated susceptor elements 3. The elongated susceptor elements 3 within the substrate element 110 are all aligned along their length dimension (main dimension) substantially parallel to a predefined reference axis of the aerosol-generating article (corresponding to the reference axis R of the sheet material) (here the length axis 101 of the article), the predefined reference axis being chosen such that, in use, it coincides with the orientation M of the field lines of an alternating magnetic field used to inductively heat the elongated susceptor elements 3, for example when the aerosol-generating article is engaged with an aerosol-generating device providing the alternating magnetic field. As previously mentioned, if the elongated susceptor elements 3 are all aligned parallel to the orientation M of the alternating magnetic field, the heating efficiency is at a maximum.

[0133] For purposes of this specification and accompanying claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about." Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges, unless otherwise indicated. Accordingly, in this context, a number A is understood as A ± 5% of A. In this context, a number A can be considered to include values within the general standard error of a measurement of a property modified by the number A. In certain instances in the appended claims, the number A can deviate from the percentage listed above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed application. Additionally, all ranges include the maximum and minimum points disclosed and include any intermediate ranges, unless otherwise indicated.

Claims

1. A method of aligning elongate susceptor elements in an aerosol-forming substrate for use in an inductively heatable aerosol-generating article, the method comprising the steps of: - providing an aerosol-forming substrate in the form of a sheet material to an alignment device, the aerosol-forming substrate comprising a plurality of elongate susceptor elements, the alignment device comprising at least one comb having a plurality of teeth arranged in a row; and - moving the alignment device and the sheet material relative to each other such that the elongate susceptor elements passing between the teeth of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

2. A method according to claim 1, wherein the elongate susceptor elements are deposited on a major surface of the sheet material.

3. A method according to claim 1, wherein the elongate susceptor elements are dispersed throughout the aerosol-forming substrate provided as a sheet material.

4. A method according to any one of the preceding claims, wherein the elongate susceptor elements are at least partially aligned such that an angle between a length dimension of the elongate susceptor elements and the reference axis is in the range of +30 degrees and -30 degrees, preferably +25 degrees and -25 degrees, in particular +10 degrees and -10 degrees.

5. A method according to any one of the preceding claims, wherein the elongate susceptor elements are aligned substantially parallel to each other and parallel to the reference axis.

6. A method according to any one of the preceding claims, wherein during the alignment of the elongate susceptor elements, the sheet material is moved relative to, in particular past, the alignment device in a transport direction, the transport direction being preferably parallel to a plane defined by the sheet material or parallel to a plane tangential to the sheet material at an alignment position.

7. A method according to claim 6, wherein the transport direction is substantially parallel to the reference axis.

8. A method according to any one of claims 6 or 7, wherein the sheet material is moved relative to, in particular past, the alignment device in the transport direction by means of a substrate conveyor belt or by means of one or more rollers.

9. A method according to any one of the preceding claims, wherein the alignment device comprises a plurality of combs, wherein each comb preferably has a different width of tooth spacing, and wherein the plurality of combs are arranged along the reference axis of the sheet material in an order of decreasing width of tooth spacing.

10. A method according to any one of the preceding claims, wherein the teeth of the at least one comb are pre-stressed, in particular in a direction substantially parallel to the reference axis of the sheet material.

11. A method according to any one of the preceding claims, wherein the aerosol-forming substrate is made from a substrate slurry cast into the form of the sheet material.

12. A method according to claim 11, wherein the elongate susceptor elements are deposited on a major surface of the sheet material or dispersed throughout the sheet material prior to drying the cast substrate slurry.

13. A method according to any one of the preceding claims, wherein the aerosol-forming substrate in the form of the sheet material is a continuous substrate sheet.

14. A method according to any one of the preceding claims, wherein the ratio of the length dimension to the largest transverse dimension of the elongate 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, most preferably greater than 35.

15. An apparatus for aligning elongate susceptor elements in / on an aerosol-forming substrate, in particular for use in a method according to any one of the preceding claims, the apparatus comprising: an alignment device comprising at least one comb having a plurality of tines arranged in a row; and a substrate supply for providing an aerosol-forming substrate in the form of a sheet material to or past the alignment device, the aerosol-forming substrate comprising elongate susceptor elements, wherein the apparatus is configured to move the alignment device and the sheet material relative to each other such that the elongate susceptor elements passing between the tines of the at least one comb are at least partially aligned relative to a reference axis of the sheet material.

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