EP4669139A1

EP4669139A1 - METHOD AND DEVICE FOR APPLYING OLDER SUSCEPTOR ELEMENTS TO AN AEROSOL-GENERATING SUBSTRATE

Info

Publication number: EP4669139A1
Application number: EP24705531.2A
Authority: EP
Inventors: Oleg Mironov; Andreas Michael ROSSOLL; Alessio DI GIUSEPPE; Lorenzo BENASSI; Julien Vidal
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-02-22
Filing date: 2024-02-21
Publication date: 2025-12-31
Also published as: KR20250151642A; WO2024175654A1; CN120787121A; JP2026506731A

Abstract

The present invention relates to a method and an apparatus for applying elongate susceptor elements (3) to an aerosol-forming substrate (14) for use in an inductively heatable aerosol-generating article, the method comprising the steps of providing an aerosol-forming substrate (14) in the form of a sheet material; providing elongate susceptor elements (3); dispersing the elongate susceptor elements (3) in a fluid medium (4); supplying the elongate susceptor elements (3) dispersed in the fluid medium (4) to and passing them through an applicator comprising at least one convergent applicator nozzle (1) causing the elongate susceptor elements (3) dispersed in the fluid medium (4) to be discharged from the at least one convergent applicator nozzle (1) in at least partial alignment along a direction of discharge (D) of the at least one convergent applicator nozzle (1); depositing the elongate susceptor elements (3) dispersed in the fluid medium (4), being discharged from the at least one convergent applicator nozzle (1) in at least partial alignment, on a main surface of the sheet material.

Description

METHOD AND APPARATUS FOR APPLYING ELONGATE SUSCEPTOR ELEMENTS TO AN AEROSOL-FORMING SUBSTRATE

The present disclosure relates to a method of applying elongate susceptor elements to an aerosol-forming substrate for use in an inductively heatable aerosol-generating article. The disclosure further relates to an apparatus for applying elongate susceptor elements to an aerosolforming substrate, in particular for use in a method according to the present disclosure.

Aerosol-generating systems using induction heating for generating inhalable aerosols are generally known from prior art. Such systems may comprise an inductively heating aerosolgenerating device and a separate aerosol-generating article for use with the device. Among other components, the article may include an aerosol-forming substrate capable to form an inhalable aerosol when heated, and an inductively heatable susceptor arrangement in thermal proximity or direct physical contact with the substrate for heating the same. Inductive heating of the susceptor arrangement is accomplished by interaction of the susceptor arrangement with an alternating magnetic field that is provided by the aerosol-generating device. In operation, the alternating magnetic field induces at least one of heat-generating eddy currents or hysteresis losses in the susceptor arrangement, causing the latter to heat up to a temperature sufficient to release volatile compounds from the heated substrate, which subsequently can cool down to form an aerosol.

Depending on the type of substrate and the shape of the article, different configurations of susceptor element susceptor arrangements are known. As an example, the article may comprise a single solid susceptor element, such as a susceptor strip, that is embedded in a solid or gel-like aerosol-forming substrate within a substrate portion of the article. While solid susceptor element are easily available at low cost, they form a single central heat source which can result in inhomogeneous 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 peripheral regions of the substrate portions are heated only indirectly by means of heat conduction across adjacent substrate layers. In particular, the high temperature gradient may cause the inner regions of the substrate portion in the vicinity of the susceptor element to overheat, whereas the temperature in the peripheral regions of the substrate portion may be too low for volatilizing the substrate. Moreover, the heating efficiency of this configuration is rather sensitive to a proper positioning of the susceptor element within the substrate. All this may cause a non-optimal exploitation of the aerosol-forming substrate. Alternatively, articles have been proposed that comprise spherical or quasi-spherical susceptor particles homogenously disturbed throughout the aerosol-forming substrate. Whilst leading to a more homogenous heating of the substrate, the heating efficiency of this susceptor configuration is limited which may also impact the extraction efficiency. Therefore, it would be desirable to have an inductively heatable aerosol-forming substrate and an apparatus for manufacturing such an aerosol-forming substrate with the advantages of prior art solutions, whilst mitigating their limitations. In particular, it would be desirable to have an aerosol-forming substrate which provide a more efficient heating and exploitation of the aerosolforming substrate.

According to an aspect of the present invention, a method of applying elongate susceptor elements to an aerosol-forming substrate for use in an inductively heatable aerosol-generating article is disclosed.

The method comprises the step of providing an aerosol-forming substrate in the form of a sheet material.

The method further comprises the step of providing elongate susceptor elements.

The method further comprises the step of dispersing the elongate susceptor elements in a fluid medium.

The method further comprises the step of supplying the elongate susceptor elements dispersed in the fluid medium to an applicator and passing them through the applicator. The applicator comprises at least one convergent applicator nozzle causing the elongate susceptor elements dispersed in the fluid medium to be discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle.

The method further comprises the step of depositing the elongate susceptor elements dispersed in the fluid medium, being discharged from the at least one convergent applicator nozzle in at least partial alignment, on a main surface of the sheet material.

In general, the term "convergent applicator nozzle" as used herein refers to a nozzle with an inner channel for passing the fluid medium with the elongate susceptor elements therein along a flow path and discharging the fluid along a direction of discharge, wherein a cross-sectional area of the inner channel along the flow path is decreasing at least along a portion of the flow path. The convergent applicator nozzle has therefore a restriction portion at least along portion of the flow path.

The elongate susceptor elements dispersed in the fluid medium are passed through the inner channel of the at least one convergent applicator nozzle, wherein the dispersed elongate susceptor elements, when passing through the restriction portion of the convergent applicator nozzle, are at least partially aligned due to shear stress (shear-induced alignment) along a flow path of the convergent applicator nozzle. The convergent applicator nozzle is designed such that, after alignment of the dispersed elongate susceptor elements, the elongate susceptor elements are discharged from the convergent applicator nozzle and deposited on the main surface of the sheet material in at least partial alignment. As used herein, the term "elongate susceptor element" refers to a susceptor element having a greater extent in one predominant dimension than in the two remaining dimensions perpendicular to the predominant dimension. As such, the elongate susceptor element may also be denoted as I D-elongate susceptor element (synonym for one-dimensionally-elongate susceptor element) or quasi-1 D susceptor element (synonym for quasi-one-dimensional susceptor element). In particular, the term "elongate susceptor element" may refer to a susceptor element that has a length dimension greater than any transverse dimension perpendicular to the length dimension. More particularly, the I D-elongate susceptor element may be an elongate or a prolate susceptor element.

Although the present invention is described herein with respect to elongate susceptor elements having a length dimension greater than any transverse dimension perpendicular to the length dimension, that is, with respect to I D-elongate susceptor element having a greater extent in one predominant dimension than in the two remaining dimensions perpendicular to the predominant dimension, it equally applies to susceptor elements having a greater extent in two (perpendicular) predominant dimensions than in the remaining dimension perpendicular to the predominant dimensions. Such susceptor elements may also be denoted as 2D-elongate susceptor elements. In particular, the present invention equally applies to susceptor elements which have a length dimension and a width dimension greater than a thickness direction, wherein the length dimension may be either greater than or substantially similar to the width dimension. More particularly, the present invention equally applies to susceptor elements which have one of an oblate cylindrical shape, such as coin shape, or an oblate-ellipsoidal shape, such as a lens shape, or a flake shape or plate shape. For these susceptor elements, the same features and advantages as described herein with respect to (I D-)elongate susceptor element equally apply and can be equally formulated by basically replacing the term "maximum length dimension of the (I D-)elongate susceptor element(s)" by "maximum extent of the 2D-elongate susceptor element(s) in the two predominant dimensions" and "maximum transverse dimension of the (1 D- )elongate susceptor element(s)" by a "maximum extent of the 2D-elongate susceptor element(s) in the remaining (non-prominent) dimension".

As compared to a single solid susceptor element, usage of a plurality of elongate susceptor elements which are dispersed throughout the aerosol-forming substrate advantageously results in a more homogenous heat distribution over the substrate without any significant temperature gradients across different substrate regions. Furthermore, where the susceptor material of the susceptor elements has a high thermal conductivity, the homogeneity of the heat distribution is further enhanced by the fact that a substrate comprising a plurality of susceptor elements dispersed therein exhibits an increased equivalent thermal conductivity as compared to a substrate without susceptor elements or with a single solid susceptor element only. Moreover, in achieving a homogeneous heat distribution, the proposed susceptor arrangement is less sensitive to the positioning of the susceptor elements as compared to a single solid susceptor element.

Most important, it was found that the geometry, in particular the relative dimensions of the susceptor elements have a major 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 elongate shape are less prone to demagnetization effects as compared to rather equidimensional susceptor elements, such as spherical or quasi-spherical susceptor particles. This can be explained as follows: When placing a susceptor element in an external magnetic field, it becomes progressively magnetized. As the external field increases, so does the internal magnetization. This process continues until the magnetization reaches the magnetic saturation point of the material, beyond which no further magnetization can occur. As a result, the magnetization of the susceptor element causes an accumulation of magnetic charge density at opposite ends of the susceptor element as seen in the direction of the external magnetic field. As a consequence, the susceptor element generates a magnetic field that causes a self-interaction with its material. This field lies along the same direction as the external magnetic field, but points opposite to it, and thus is termed the demagnetization field. The demagnetizing field depends on the geometrical shape of the susceptor element, but not on its absolute dimensions. Provided the susceptor element responds to the external magnetic field changes, the demagnetizing field is generally assumed to be proportional to the magnetization in each direction, related by a geometry dependent constant of proportionality that is known as the demagnetization factor. The demagnetization factor depends on the shape of the susceptor element as well as on its relative orientation to the external magnetic field. To this extent, it has been found that an external magnetic field running through an elongate susceptor element, such as a susceptor element having the shape of a fiber or a thin rod, with a length dimension significantly greater than any transverse dimension perpendicular to the length dimension, generates a weaker or even negligible demagnetization field as compared to a non-elongate (equidimensional) susceptor element, such as a spherical or quasi-spherical susceptor element. This can be intuitively understood since in a properly aligned elongate susceptor element the accumulated magnetic charge densities at the opposite ends of the susceptor element are more spatially distanced from each other. This causes the demagnetizing field to significantly reduce its intensity and thus to have a lesser impact on the magnetization field, which is responsible for the power losses. As a result, power losses and thus heating efficiency is greater than for an elongate susceptor element than for a non-elongate (equidimensional) susceptor element, such as spherical or quasi- spherical susceptor element. This applies especially where the orientation of the magnetic field is substantially parallel to the length dimension of the elongate susceptor element, in which configuration the heating performance is at maximum. Yet, it has been found that the elongate susceptor elements do not necessarily need to be in perfect parallel alignment with the external magnetic field direction. Even if the susceptor elements are aligned in a certain angular range about the orientation of the external magnetic field, the overall heating performance is still higher than for a susceptor arrangement with randomly oriented susceptor elements.

With a method/apparatus according to the present disclosure, there is provided a method/apparatus that allows to at least partially align the elongate susceptor elements prior to the deposition of the elongate susceptor elements such that the at least partially aligned elongate susceptor elements can be discharged in at least partial alignment and deposited on the main surface of the sheet material in at least partial alignment.

Since the overall heating performance of the elongate susceptor elements increases with a decreasing deviation from an alignment substantially parallel to the alternating magnetic field used for induction heating, the elongate susceptor elements may be aligned preferably such that an angle between the length dimension of the elongate susceptor elements and the direction of discharge 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. Therefore, the elongate susceptor elements may be deposited on the main surface of the sheet material in a similar alignment, thereby increasing the heating performance. As used herein, the terms "(at least) partial alignment" or "(at least) partially aligned" refer to this kind of alignment, in particular in the above-defined angular ranges.

As used herein, the term “direction of discharge” may refer to the flow direction of the elongate susceptor elements dispersed in the fluid medium when exiting from the nozzle.

As stated above, the heating performance is at maximum for a substantially parallel alignment. Accordingly, the elongate susceptor elements are preferably aligned substantially parallel to the direction of discharge. As used herein, the term "substantially parallel" is understood as "parallel ± 5° degrees deviation from a parallel arrangement".

The convergent applicator nozzle is preferably arranged vertically above the sheet material at a place of deposition on the main surface. By providing the convergent applicator nozzle arranged vertically above the sheet material, the elongate susceptor elements may be easily deposited on the main surface of the sheet material by gravity. As used herein, the term “arranged vertically above” is understood as lying in a projection of a plane of the sheet material or a projection of a plane tangent to the sheet material at the place of deposition above the sheet material when the convergent applicator nozzle is operational conditions.

As used herein, the term “place of deposition” may refer to the current surface portion of the sheet material where the elongate susceptor elements are deposited at given time during the discharge and deposition process when discharged from the convergent applicator nozzle along the direction of discharge. Alternatively, the convergent applicator nozzle may be arranged vertically below the sheet material at a place of deposition on the main surface. Therefore, elongate susceptor elements that have not been correctly deposited on the main surface and/or are not adhering to the main surface as desired, for example elongate susceptor elements deposited at least partially overlapping other elongate susceptor elements, would fall off the main surface by gravity.

According to another alternative, the convergent applicator nozzle may be preferably arranged horizontally beside the sheet material at a place of deposition on the main surface. As used herein, the term “arranged horizontally beside” is understood as lying in a projection of a plane of the sheet material or a projection of a plane tangent to the sheet material at the place of deposition lateral to the sheet material when the convergent applicator nozzle is operational conditions.

Whenever in this disclosure a number or a range is given for a plurality of a objects, such as for the plurality of susceptor elements, this means that the number or the range applies to at least 60 percent, in particular at least 70 percent, more particularly at least 80 percent, especially at least 90 percent of all objects out of the plurality of a objects, preferably for all objects out of the plurality of a objects. For example, where the present disclosure states that the elongate susceptor elements are aligned such that an angle between the length dimension of the elongate susceptor elements and direction of discharge is in a range between +A degrees and -A degrees, this means that at least 60 percent, in particular at least 70 percent, more particularly at least 80 percent, especially at least 90 percent of all elongate susceptor elements are aligned such that an angle between the length dimension of the elongate susceptor elements and the direction of discharge is in a range between +A degrees and -A degrees.

During deposition the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle and the sheet material may be moved relative to each other.

The sheet material may be moved relative to (in particular past) the at least one convergent applicator nozzle in a conveying direction, either continuously or stepwise. The conveying direction may preferably be parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition. This improves the manufacturing process by allowing deposition of the elongate susceptor elements on a continuous substrate sheet.

A projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition may be preferably substantially parallel to the conveying direction.

The sheet material may be moved relative to (in particular past) the at least one convergent applicator nozzle in the conveying direction, either continuously or stepwise, by means of a conveyor belt or by means of one or more rollers. Moving the sheet material relative (in particular past) the at least one convergent applicator nozzle has the advantage that the relative movement of the at least one convergent applicator nozzle relative to the sheet material also improves the deposition in at least partial alignment of the elongate susceptor elements on the main surface of the sheet material.

During deposition of the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle may be moved relative (in particular across) to the sheet material in a direction transverse, preferably perpendicular to the conveying direction. This allows for a deposition of the elongate susceptor elements on the sheet material without the need of providing convergent applicator nozzles over the whole width of the sheet material.

During deposition of the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle may be preferably moved relative to (in particular across) the sheet material in a plane parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition, especially in a direction transverse to the direction of discharge and/or in a direction parallel to a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition. This preferred embodiment also allows for a deposition of the elongate susceptor elements on the sheet material without the need of providing convergent applicator nozzles over the whole width of the sheet material. This preferred embodiment allows also for deposition of the elongate susceptor elements, in particular on a continuous substrate sheet.

During deposition of the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle may, in another preferred embodiment, oscillate in a pendulum movement around a pendulum axis.

The pendulum axis may be preferably aligned transverse, in particular perpendicular, to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition. This enables the deposition of the elongate susceptor elements on the main surface of the sheet material over a greater surface compared to a fixedly arranged convergent applicator nozzle.

The applicator may comprise a plurality of convergent applicator nozzles. During deposition of the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the convergent applicator nozzles may oscillate in a pendulum movement around a common pendulum axis. Alternatively, during deposition of the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, each of the convergent applicator nozzles may oscillate in a pendulum movement around a respective pendulum axis associated to each of the convergent applicator nozzles. The common pendulum axis or each of the respective pendulum axis may be preferably aligned transverse, in particular perpendicular, to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition.

In a preferred embodiment, an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane defined by the sheet material may be in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, more preferably between 10 degrees and 45 degrees. Alternatively, an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane tangent to the sheet material at a place of deposition may be in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, more preferably between 10 degrees and 45 degrees. The preferred angles also allow for an optimal deposition of the elongate susceptor elements in at least partial alignment on the main surface of the sheet material, in particular when the sheet material is moved relative (in particular past) the at least one convergent applicator nozzle.

Preferably, the at least one convergent applicator nozzle may be a wide jet applicator nozzle. A wide jet applicator nozzle is particularly preferred since it allows deposition of the elongate susceptor elements over a great width of the sheet material, therefore reducing the amount of necessary convergent applicator nozzles, in particular where the sheet material is moved relative (in particular past) the at least one convergent applicator nozzle.

The wide jet applicator nozzle may comprise a partition defining a plurality of applicator nozzle channels.

A minimum cross-sectional area of the at least one convergent applicator nozzle may have a circular shape or a rectangular shape or an elliptical shape or a quadratic shape or a polygonal shape. As used herein, the term “minimum cross-sectional area” is understood as the cross- sectional area of the inner channel of the convergent applicator nozzle with the lowest cross- sectional area compared to other cross-sectional areas along the flow path and may be alternatively referred to as the minimum cross-sectional area of the restriction portion of the convergent applicator nozzle. In particular when the elongate susceptor elements are provided as 2D-elongate susceptor elements, a rectangular shape having a greater extent in its transverse dimension compared to its height dimension is particularly advantageous for providing at least partial alignment of the 2D-elongate susceptor elements.

Depending on elongate susceptor elements provided to the convergent applicator nozzle and in particular the maximum extent of the length dimension, the minimum cross-sectional area of the at least one convergent applicator nozzle may be chosen such to have the optimal shape for providing the desired at least partial alignment of the elongate susceptor elements.

A transverse dimension of a minimum cross-sectional area of the at least one convergent applicator nozzle may be preferably in a range between 0.5 and 1.5, in particular between 0.75 and 1.25, more preferably between 0.9 and 1.1 times a length dimension, preferably a mean length dimension, of the elongate susceptor elements.

A transverse dimension of a minimum cross-sectional area of the at least one convergent applicator nozzle may also be in a range between 0.1 millimeter and 20 millimeters, in particular 0.25 millimeter and 10 millimeters, preferably between 0.5 millimeter and 5 millimeters. It has been shown that these values of the minimum cross-sectional area of the at least one convergent nozzle allow for very good results with regard to alignment of the elongate susceptor elements.

Preferably, the elongate susceptor elements may be dispersed in the fluid medium upstream of the at least one convergent applicator nozzle. Alternatively or additionally, the elongate susceptor elements may be dispersed in the fluid medium in the convergent applicator nozzle upstream of the restriction portion.

The fluid medium may be one of water, glycerine, air, nitrogen, and ethanol. Combinations thereof may also be possible.

The aerosol-forming substrate may be preferably made from a substrate slurry casted into the form of the sheet material, wherein the elongate susceptor elements are deposited on the casted substrate slurry. Depending on the firmness of the casted substrate slurry, the elongate susceptor elements may be at least partially embedded within the substrate sheet after or during deposition.

The elongate susceptor elements may be preferably deposited on the main surface of the sheet material prior to drying the casted substrate slurry. This is in particular done for achieving improved bonding of the elongate susceptor elements with the sheet material during subsequent drying.

The aerosol-forming substrate in the form of the sheet material may preferably be a continuous substrate sheet. As has been already described above, a continuous substrate sheet is particularly advantageous with respect to manufacturing, in particular when the continuous substrate sheet is moved relative to (in particular past) the at least one convergent applicator nozzle.

To further improve manufacturing of the aerosol-forming substrate, the elongate susceptor elements may be deposited on the main surface of the sheet material during or after crimping the continuous substrate sheet, in particular during or after crimping the continuous substrate sheet in a longitudinal direction. The longitudinal direction may be a machine direction of the continuous substrate sheet, preferably parallel to the conveying direction. Deposition of the elongate susceptor elements during or after crimping has the advantage that, since the sheet material is corrugated, the created corrugations are particularly advantageous for accommodating the elongate susceptor elements during depositing, thereby simplifying depositing and also improving alignment and distribution of the elongate susceptor elements.

As discussed above, the geometry, in particular the relative dimensions of the elongate susceptor elements have a major impact on the heating efficiency and thus on the extraction efficiency of the substrate. Therefore, the elongate susceptor elements may be selected such as having a ratio of a length dimension to a maximum transverse dimension 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. The term “maximum transverse dimension” as used herein refers to a greatest dimension of the susceptor wire perpendicular to the predominant dimension (length dimension). This ratio may also be denoted as aspect ratio or form factor.

Preferably, the aspect ratio or the form factor does not only have a lower limit but also an upper limit. Accordingly, the aspect ratio of the maximum extent of the elongate susceptor elements in the length dimension to the maximum extent in the remaining (non-predominant) dimensions is in a range between 4 and 500, in particular between 10 and 300, preferably between 20 and 200, more preferably between 30 and 100.

The maximum extent of the elongate susceptor elements in the length dimension may be in a range between 20 micrometer and 50 millimeter, in particular 100 micrometer and 16 millimeter, preferably between 0.5 millimeter and 5 millimeter. Such maximum extents in the length dimension are advantageous with regard to dispersing the elongate susceptor elements in the fluid medium and at least partially aligning the elongate susceptor elements when passing through the convergent applicator nozzle.

Depending on the respective absolute values of the length dimension, the respective absolute value of the maximum extent in the remaining (non-predominant) dimensions is preferably chosen such that the form factor is above the above-defined lower limit, Accordingly, the maximum extent of the elongate susceptor elements in the remaining (non-predominant) dimensions is equal to or smaller than 500 micrometer, in particular 100 micrometer, preferably 50 micrometer, more preferably 25 micrometer. Likewise, the maximum extent of the elongate susceptor elements in the remaining (non-predominant) dimensions is in a range between 5 micrometer and 500 micrometer, in particular 10 micrometer and 150 micrometer, preferably 80 micrometer and 120 micrometer. As an example, an elongate susceptor element may have a length dimension (maximum extent in the predominant dimension) of about 2 millimeter and a maximum transverse extent (maximum extent in the two remaining (non-prominent) dimensions) of about 25 micrometer.

In general, the elongate susceptor elements may have any geometrical shape, as long as it is elongate in one dimension. In particular, the elongate susceptor elements may have one of an elongate cylindrical shape or a prolate-ellipsoidal shape. As an example, the elongate susceptor elements may be fiber elements, in particular chopped fiber elements or milled fiber elements. As another example, the elongate susceptor elements may be wire elements or thread elements or grain elements or rod elements. Advantageously, the fiber elements or the wire elements or the thread elements or the grain elements or the filament elements or the rod elements are made of a material that is inductively heatable, such as metal fibers, or metal wires or metal threads, are easily available at low cost.

Preferably, a cross-section of the elongate susceptor elements in a plane perpendicular to the predominant dimension, that is the length dimension of the elongate susceptor element, may have a circular shape or an oval shape or an elliptical shape or a triangular shape or a rectangular shape or a quadratic shape or polygonal shape. If the cross-section is circular, the above- mentioned maximum extent of the elongate susceptor elements in the remaining (non- predominant) dimensions corresponds to the diameter of the elongate susceptor elements, where it is at maximum along the predominant dimension, that is, the length dimension of the elongate susceptor elements. If the cross-section is oval or elliptical, the above-mentioned maximum extent of the elongate susceptor elements corresponds to the length of the semimajor axis of the oval or elliptical cross-section, where it is at maximum along the predominant dimension, that is, the length dimension of the elongate susceptor elements. If the cross-section is quadratic or in general rectangular, the above-mentioned maximum extent of the elongate susceptor elements corresponds to the length of the edge/major edge of the quadratic/rectangular cross-section.

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

According to the present invention, a susceptor material of the elongate susceptor elements is ferromagnetic or ferrimagnetic. In addition, the susceptor material of the elongate susceptor elements may be electrically conductive.

Preferably the susceptor material of the elongate susceptor elements comprises or consists of a metal, for example ferritic iron, or stainless steel, in particular a grade 410, grade 420, or grade 430 stainless steel. Alternatively, the susceptor material of the elongate susceptor elements may comprise a ferrimagnetic ceramic. In addition to the susceptor material, the elongate susceptor elements may further comprise a ferromagnetic or ferrimagnetic temperature marker material.

While the susceptor material is optimized with regard to heat loss and thus heating efficiency, the temperature marker material is a magnetic (ferro- or ferrimagnetic) material that is chosen such as to have a Curie temperature which essentially corresponds to a predefined temperature point of the heating process.

The temperature marker material may 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 elongate susceptor elements may have a Curie temperature in a range between 180 °C and 420 °C, in particular between 210 °C and 380 °C, preferably between 250 °C and 380 °C. Even though the temperature marker material primarily is a functional material providing a temperature marker by its Curie temperature, it may also contribute to the inductive heating process of the susceptor arrangement.

The temperature marker material of the elongate susceptor elements may comprise or may consist of nickel or a nickel alloy

The susceptor elements may be formed such that the susceptor material is surrounded or covered at least partially, preferably entirely by the temperature marker material.

In addition, the elongate susceptor elements may comprise an outer protective coating surrounding the susceptor material and - if present - the temperature marker material. Preferably, the protective coating is an anti-corrosion coating. Advantageously, the protective coating makes the elongate susceptor elements resistant to external influences, especially corrosive influences.

The elongate susceptor elements provided to the at least one convergent applicator nozzle may have substantially identical characteristics such as susceptor material, maximum extent, form ratio, temperature marker material, outer coating etc. Alternatively, a mixture of elongate susceptor elements may be dispersed in the fluid medium, for example a mixture of susceptor elements with different characteristics such as susceptor material, maximum extent, form ratio, temperature marker material, outer coating etc.

It is also possible that the susceptor material of the susceptor elements itself has a temperature marker function. That is, the elongate susceptor elements may comprise a single material which acts both as a susceptor material and as a temperature marker material.

The present invention also relates to an apparatus for applying elongate susceptor elements to an aerosol-forming substrate. The apparatus may be used preferably in combination with a method for applying elongate susceptor elements to an aerosol-forming substrate described above. Therefore, the above description of preferred embodiments of the method for applying elongate susceptor elements to an aerosol-forming substrate and their advantages are analogously valid for the apparatus according to the present invention. The apparatus comprises a susceptor supply for providing the elongate susceptor elements and a fluid medium supply for providing a fluid medium.

The apparatus further comprises a mixer coupled to the susceptor supply and the fluid medium supply for dispersing the elongate susceptor elements in the fluid medium.

An applicator comprising at least one convergent applicator nozzle is also comprised by the apparatus. The at least one convergent applicator nozzle is configured such that the elongate susceptor elements dispersed in the fluid medium are discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle. As cited above with respect to the method according to the present invention, the mixer may be arranged upstream of the at least one convergent applicator nozzle or may be arranged in the at least one convergent applicator nozzle, upstream of the restriction portion.

The apparatus may further comprise a substrate supply for providing an aerosol-forming substrate in the form a sheet material to or past the at least one convergent applicator nozzle, enabling the at least one convergent applicator nozzle to deposit the elongate susceptor elements dispersed in the fluid medium in at least partial alignment on the main surface of the sheet material.

The substrate supply may preferably comprise a conveyer belt or one or more rollers for providing the aerosol-forming substrate in the form the sheet material, past the at least one convergent applicator nozzle in a conveying direction, either continuously or stepwise. The conveying direction may be preferably parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition when being provided past the convergent applicator nozzle. This particular embodiment is particularly advantageous when a continuous substrate sheet is provided to the apparatus.

The at least one convergent applicator nozzle may be preferably configured and arranged such that a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition when being provided past the convergent applicator nozzle is substantially parallel to the conveying direction.

The at least one convergent applicator nozzle may be preferably configured and arranged to be moved relative to (in particular across) the sheet material in a direction transverse, preferably perpendicular to the conveying direction.

The at least one convergent applicator nozzle may be preferably configured to be moved relative to (in particular past) the sheet material in a plane parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle, especially in a direction transverse to the direction of discharge and/or in a direction parallel to a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition when being provided to or past the convergent applicator nozzle.

Preferably, the at least one convergent applicator nozzle may be configured to oscillate in a pendulum movement around a pendulum axis.

The pendulum axis may be preferably aligned transverse, more preferred perpendicular, to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle.

The applicator may preferably comprise a plurality of convergent applicator nozzles. The convergent applicator nozzles being preferably configured to oscillate in a pendulum movement around a common pendulum axis. Alternatively, each of the convergent applicator nozzles may be configured to oscillate in a pendulum movement around a respective pendulum axis associated to each of the convergent applicator nozzles.

The common pendulum axis or each of the respective pendulum axis may be aligned transverse, in particular perpendicular, to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzles.

An angle between the direction of discharge of the at least one convergent applicator nozzle and a plane defined by the sheet material when being provided to or past the convergent applicator nozzle may be preferably in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, more preferred between 10 degrees and 45 degrees. Alternatively, an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle may be in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, more preferred between 10 degrees and 45 degrees.

The at least one convergent applicator nozzle may be preferably a wide jet applicator nozzle, and may in particular comprise a partition defining a plurality of applicator nozzle channels.

As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate that is capable of releasing volatile compounds when heated in order to form an aerosol. The aerosol-generating article may be a consumable, in particular a consumable to be discarded after a single use. For example, the article may be an elongate article or a rod-shaped article. The elongate or rod-shaped article may have a shape resembling the shape of conventional cigarettes. In particular, such an article may have a circular or elliptical or oval or square or rectangular or triangular or a polygonal cross-section. As another example, the article may be a cartridge including a liquid aerosol-forming substrate to be heated. As used herein, the term "aerosol-forming substrate" denotes a substrate formed from or comprising an aerosol-forming material that 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 aerosol-forming volatile compounds. Accordingly, such a substrate may be denoted as a heat-not-burn aerosol-forming substrate. Likewise, an aerosol-generating article comprising such an aerosol-forming substrate may be denoted as a heat-not-burn aerosol-generating article.

In general, the aerosol-forming substrate may comprise at least one aerosol former and at least one sensorial material both of which are volatilizable when heated. The sensorial material may comprise at least one of a tobacco-containing material, a nicotine-containing material and a flavoring substance. Examples of suitable aerosol formers are glycerin and propylene glycol. Examples of flavoring substance may be plant extracts and natural or artificial flavors.

The aerosol-forming substrate may be a solid aerosol-forming substrate or a gel-like aerosol-forming substrate, or any combination thereof.

As mentioned above, the aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds, which are released from the substrate upon heating. I. In particular, the aerosol-forming substrate may comprise reconstituted tobacco material or a tobacco-containing slurry. Accordingly, the aerosol-generating article may be a tobacco containing article. Alternatively or additionally, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may also comprise other additives and ingredients, such as nicotine or flavourants.

The aerosol-forming substrate may also be a paste-like material, a sachet of porous material comprising aerosol-forming substrate, or, for example, loose tobacco mixed with a gelling agent or sticky agent, which could include a common aerosol former such as glycerin, and which is compressed or molded into a plug.

The aerosol-forming substrate is made from a sheet material. For example, the aerosolforming substrate may be made from a crimped tobacco sheet comprising a tobacco material, organic fibers, a binder, an aerosol former. Alternatively, the aerosol-forming substrate may be made from a sheet material including a nicotine-containing material, organic fibers, a binder, an aerosol former. As yet another alternative, the aerosol-forming substrate may be made from a sheet material containing tobacco cut filler. To this extent, it has been found that the aerosolgenerating article is easy to manufacture, especially with respect to a preferred alignment of the elongate susceptor elements relative to a pre-defined reference axis of the article, if the susceptor elements are applied to the aerosol-forming substrate when it is in the form of a sheet material. This may be the result of a manufacturing process including the deposition of the susceptor elements on an outer surface of a sheet material, either during a primary process, in which the sheet material is produced, or during a secondary process, where the sheet material is machined and combined with other semi-finished goods to obtain the final product. As a result of this, the elongate susceptor elements may be finally disposed on an outer surface of the sheet material or at least partially embedded in the sheet material close to an outer surface of the sheet material. This can be observed even if the sheet material is subsequently machined, for example, crimped and gathered such as to form a substrate plug in the final article.

The invention is defined in the claims. However, below there 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 another example, embodiment, or aspect described herein.

Example Ex1 : A method of applying elongate susceptor elements to 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; providing elongate susceptor elements; dispersing the elongate susceptor elements in a fluid medium; supplying the elongate susceptor elements dispersed in the fluid medium to and passing them through an applicator comprising at least one convergent applicator nozzle causing the elongate susceptor elements dispersed in the fluid medium to be discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle; depositing the elongate susceptor elements dispersed in the fluid medium, being discharged from the at least one convergent applicator nozzle in at least partial alignment, on a main surface of the sheet material.

Example Ex2: The method according to example Ex1 , wherein the at least partial alignment is such that an angle between a length dimension of the elongate susceptor elements and the direction of discharge is in a range between +30 degrees and -30 degrees, in particular +25 degrees and -25 degrees, more particularly between +10 degrees and -10 degrees.

Example Ex3: The method according to example Ex1 , wherein the elongate susceptor elements dispersed in the fluid medium are discharged from the at least one convergent applicator nozzle in substantially parallel alignment to each other and to the direction of discharge.

Example Ex4: The method according to any one of the preceding examples, wherein the convergent applicator nozzle is arranged vertically above the sheet material at a place of deposition on the main surface.

Example Ex5: The method according to any one of the preceding examples, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle and the sheet material are moved relative to each other.

Example Ex 6: The method according to any one of the preceding examples, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the sheet material is moved relative to (in particular past) the at least one convergent applicator nozzle in a conveying direction, the conveying direction preferably being parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition.

Example Ex7: The method according to example Ex6, wherein a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition is substantially parallel to the conveying direction.

Example Ex8: The method according to any one of examples Ex6 or Ex7, wherein the sheet material is moved relative to (in particular past) the at least one convergent applicator nozzle in the conveying direction by means of a conveyor belt or by means of one or more rollers.

Example Ex9: The method according to any one of examples Ex6 to Ex8, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle is moved relative (in particular across) to the sheet material in a direction transverse, preferably perpendicular to the conveying direction.

Example Ex10: The method according to any one of the preceding examples, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle is moved relative to (in particular across) the sheet material in a plane parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition, especially in a direction transverse to the direction of discharge and/or in a direction parallel to a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition.

Example Ex11 : The method according to any one of the preceding examples, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the at least one convergent applicator nozzle oscillates in a pendulum movement around a pendulum axis.

Example Ex12: The method according to example Ex11 , wherein the pendulum axis is aligned transverse, preferably perpendicular to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition.

Example Ex13: The method according to any one of claims 1 to 10, wherein the applicator comprises a plurality of convergent applicator nozzles, and wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the convergent applicator nozzles oscillate in a pendulum movement around a common pendulum axis; or wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, each of the convergent applicator nozzles oscillates in a pendulum movement around a respective pendulum axis associated to each of the convergent applicator nozzles.

Example Ex14: The method according to example Ex13, wherein the common pendulum axis or each of the respective pendulum axis is aligned transverse, preferably perpendicular to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition.

Example Ex15: The method according to any one of the preceding examples, wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane defined by the sheet material is in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, preferably between 10 degrees and 45 degrees; or wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane tangent to the sheet material at a place of deposition is in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, preferably between 10 degrees and 45 degrees.

Example Ex16: The method according to any one of the preceding examples, wherein the at least one convergent applicator nozzle is a wide jet applicator nozzle.

Example Ex17: The method according to example Ex16, wherein the wide jet applicator nozzle comprises a partition defining a plurality of applicator nozzle channels.

Example Ex18: The method according to any one of the preceding examples, wherein a minimum cross-sectional area of the at least one convergent applicator nozzle has a circular shape or a rectangular shape or an elliptical shape or a quadratic shape or polygonal shape.

Example Ex19: The method according to any one of the preceding examples, wherein a transverse dimension of a minimum cross-sectional area of the at least one convergent applicator nozzle is in a range between 0.5 and 1.5, in particular between 0.75 and 1.25, preferably between 0.9 and 1.1 times a mean length dimension of the elongate susceptor elements.

Example Ex20: The method according to any one of the preceding examples, wherein a transverse dimension of a minimum cross-sectional area of the at least one convergent applicator nozzle is in a range between 0.1 millimeter and 20 millimeter, in particular 0.25 millimeter and 10 millimeter, preferably between 0.5 millimeter and 5 millimeter.

Example Ex21 : The method according to any one of the preceding examples, wherein the elongate susceptor elements are dispersed in the fluid medium upstream of the at least one convergent applicator nozzle.

Example Ex22: The method according to any one of the preceding examples, wherein the fluid medium is one of water, glycerine, air, nitrogen, and ethanol.

Example Ex23: The method according to any one of the preceding examples, wherein the aerosol-forming substrate is made from a substrate slurry casted into the form of the sheet material, wherein the elongate susceptor elements are deposited on the casted substrate slurry.

Example Ex24: The method according to example Ex23, wherein the elongate susceptor elements are deposited on the main surface of the sheet material prior to drying the casted substrate slurry.

Example Ex25: The method according to any one of the preceding examples, wherein the aerosol-forming substrate in the form of the sheet material is a continuous substrate sheet.

Example Ex26: The method according to example Ex25, wherein the elongate susceptor elements are deposited on the main surface of the sheet material after crimping the continuous substrate sheet, especially after crimping the continuous substrate sheet in a longitudinal direction, in particular in a machine direction of the continuous substrate sheet.

Example Ex27: The method according to any one of the preceding examples, wherein the elongate susceptor elements have a greater extent in one length dimension than in the two transverse dimensions, and wherein an aspect ratio of a maximum extent of the elongate susceptor elements in the length dimension to a maximum extent of the elongate susceptor elements in the transverse dimensions 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.

Example Ex28: The method according to any one of the preceding examples, wherein the aspect ratio of the maximum extent of the elongate susceptor elements in the length dimension to the maximum extent in the transverse dimensions is in a range between 4 and 500, in particular between 10 and 300, preferably between 20 and 200, more preferably between 30 and 100.

Example Ex29: The method according to any one of the preceding examples, wherein the maximum extent of the elongate susceptor elements in the length dimension is in a range between 20 micrometer and 50 millimeter, in particular 100 micrometer and 16 millimeter, preferably between 0.5 millimeter and 5 millimeter.

Example Ex30: The method according to any one of the preceding examples, wherein the maximum extent of the elongate susceptor elements in the transverse dimensions is a range between 5 micrometer and 500 micrometer, in particular 10 micrometer and 150 micrometer, preferably 80 micrometer and 120 micrometer.

Example Ex31 : The method according to any one of the preceding examples, wherein the maximum extent of the elongate susceptor elements in the transverse dimensions is equal to or smaller than 500 micrometer, in particular 100 micrometer, preferably 50 micrometer, more preferably 25 micrometer.

Example Ex32: The method according to any one of the preceding examples, wherein the elongate susceptor elements have one of an elongate cylindrical shape or a prolate-ellipsoidal shape. Example Ex33: The method according to any one of the preceding examples, wherein the elongate susceptor elements are one of fiber elements, in particular chopped fiber elements or milled fiber elements, or wire elements, or thread elements, or grain elements or rod elements.

Example Ex34: The method according to any one of the preceding examples, wherein a cross-section of the elongate susceptor elements in a plane perpendicular to the length dimension has a circular shape or an oval shape or an elliptical shape or a triangular shape or a rectangular shape or a quadratic shape or polygonal shape.

Example Ex35: The method according to any one of the preceding examples, wherein a susceptor material of the elongate susceptor elements is electrically conductive or non- conductive, and either ferromagnetic or ferrimagnetic.

Example Ex36: The method according to Example Ex35, wherein the susceptor material of the elongate susceptor elements comprises or consists of a metal, for example ferritic iron, or stainless steel, in particular a grade 410, grade 420, or grade 430 stainless steel; or a ferrimagnetic ceramic.

Example Ex37: The method according to any one examples Ex35 or Ex36, wherein the elongate susceptor elements further comprise a ferromagnetic or ferrimagnetic temperature marker material in addition to the susceptor material, in particular with a Curie temperature in a range between 180 °C and 420 °C, in particular between 210 °C and 380 °C, preferably between 250 °C and 380 °C.

Example Ex38: The method article according to example Ex37, wherein the temperature marker material of the elongate susceptor elements comprises or consists of nickel or a nickel alloy.

Example Ex39: An apparatus for applying elongate susceptor elements to an aerosolforming substrate, in particular for use in a method according to any one of the preceding examples, the apparatus comprising: a susceptor supply for providing the elongate susceptor elements; a fluid medium supply for providing a fluid medium; a mixer coupled to the susceptor supply and the fluid medium supply for dispersing the elongate susceptor elements in the fluid medium; an applicator comprising at least one convergent applicator nozzle which is configured such that the elongate susceptor elements dispersed in the fluid medium are discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle.

Example Ex 40: The apparatus according to example Ex39, further comprising a substrate supply for providing an aerosol-forming substrate in the form a sheet material to or past the at least one convergent applicator nozzle, enabling the at least one convergent applicator nozzle to deposit the elongate susceptor elements dispersed in the fluid medium in at least partial alignment on the main surface of the sheet material. Example Ex41 : The apparatus according to example Ex40, wherein the substrate supply comprises a conveyer belt or one or more rollers for providing the aerosol-forming substrate in the form the sheet material past the at least one convergent applicator nozzle in a conveying direction, the conveying direction preferably being parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition when being provided past the convergent applicator nozzle.

Example Ex42: The apparatus according to example Ex41 , wherein the at least one convergent applicator nozzle is configured and arranged such that a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition when being provided past the convergent applicator nozzle is substantially parallel to the conveying direction.

Example Ex43: The apparatus according to any one of examples Ex41 or Ex42, wherein the at least one convergent applicator nozzle is configured and arranged to be moved relative to (in particular across) the sheet material in a direction transverse, preferably perpendicular to the conveying direction.

Example Ex44: The apparatus according to any one of examples Ex39 to Ex43, wherein the at least one convergent applicator nozzle is configured to be moved relative to (in particular past) the sheet material in a plane parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle, especially in a direction transverse to the direction of discharge and/or in a direction parallel to a projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition when being provided to or past the convergent applicator nozzle.

Example Ex45: The apparatus according to any one of examples Ex39 to Ex44, wherein the at least one convergent applicator nozzle is configured to oscillate in a pendulum movement around a pendulum axis.

Example Ex46: The apparatus according to example Ex45, wherein the pendulum axis is aligned transverse, preferably perpendicular to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle.

Example Ex47: The apparatus according to any one of examples Ex39 to Ex46 wherein the applicator comprises a plurality of convergent applicator nozzles, and wherein the convergent applicator nozzles are configured to oscillate in a pendulum movement around a common pendulum axis or wherein each of the convergent applicator nozzles is configured to oscillate in a pendulum movement around a respective pendulum axis associated to each of the convergent applicator nozzles. Example Ex48: The apparatus according to example Ex47, wherein the common pendulum axis or each of the respective pendulum axis is aligned transverse, preferably perpendicular to a plane defined by the sheet material or to a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzles.

Example Ex49: The method according to any one of examples Ex39 to Ex48, wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane defined by the sheet material when being provided to or past the convergent applicator nozzle is in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, preferably between 10 degrees and 45 degrees; or wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle is in a range between 0 degrees and 90 degrees, in particular between 0 degrees and 80 degrees, preferably between 10 degrees and 45 degrees.

Example Ex50: The apparatus according to any one of examples Ex39 to Ex49, wherein the at least one convergent applicator nozzle is a wide jet applicator nozzle.

Example Ex51 : The apparatus according to example Ex50, wherein the wide jet applicator nozzle comprises a partition defining a plurality of applicator nozzle channels.

Examples will now be further described with reference to the figures in which:

Fig. 1A shows schematically an exemplary embodiment of a convergent applicator nozzle;

Fig. 1 B shows schematically the at least partial alignment of the elongated susceptor elements;

Fig. 2 shows schematically an exemplary embodiment of an apparatus according to the present invention;

Fig. 3 shows schematically another exemplary embodiment of an apparatus according to the present invention;

Fig. 4 shows schematically a detail of another exemplary embodiment of an apparatus according to the present invention;

Fig. 5 shows schematically yet another exemplary embodiment of an apparatus according to the present invention;

Fig. 6 shows schematically in a simplified lateral view an apparatus according to the present invention;

Fig.7 shows schematically in a simplified lateral view another embodiment of an apparatus according to the present invention;

Fig. 8 shows a flowchart of an embodiment of the method according to the present invention; and

Fig. 9 shows schematically a detail of an aerosol-generating article comprising an aerosol- forming substrate and elongate susceptor elements manufactured according to the present invention.

All the examples shown in the figures are schematic and not to scale.

In Fig. 1 A, an example of a convergent applicator nozzle 1 attached to a conduit 2 is shown schematically in cross-section. The conduit 2 is provided upstream of the convergent applicator nozzle 1 for providing elongate susceptor elements 3 dispersed in a fluid medium 4. The convergent applicator nozzle 1 comprises a hollow body 5 defining an inner channel 6 for flowing the fluid 4 and the elongate susceptor elements 3 dispersed therein along a flow path F denoted schematically by the arrow F. The convergent applicator nozzle 1 further comprises a restriction portion 7 with a decreasing cross-sectional area along the flow path F, as compared to the second portion 8 with a constant cross-sectional area along the flow path F.

The elongate susceptor elements 3 dispersed in the fluid medium 4 are passed through the inner channel 6 of the convergent applicator nozzle 1. When passing through the restriction portion 7 of the convergent applicator nozzle 1 , the dispersed elongate susceptor elements 3 are at least partially aligned due to shear stress (shear-induced alignment) along the flow path F of the convergent applicator nozzle 1 . The convergent applicator nozzle 1 is designed such that, after at least partial alignment of the dispersed elongate susceptor elements 3, the elongate susceptor elements 3 are discharged from the convergent applicator nozzle 1 along a direction of discharge D, denoted schematically by the arrow D. In the example of Fig. 1 A, the flow path F and the direction of discharge D are parallel to each other, but, depending on the design of the convergent applicator nozzle 1 , the direction of discharge D may be angled with respect to the flow path F. In the example shown in Fig. 1A, the elongate susceptor elements 3 are discharged in substantially parallel alignment to each other and to the direction of discharge D. Accordingly, the elongate susceptor elements 3 may be deposited in substantially parallel alignment to each other on a main surface of an aerosol forming substrate provided as a sheet material. In this case, the elongate susceptor elements 3 may be also deposited substantially parallel to a projection of the direction of discharge onto a plane defined by the sheet material or onto a plane tangent to the sheet material at a place of deposition.

Alternatively, as shown in the detail of Fig. 1 B, the elongate susceptor elements 3 may be discharged in at least partial alignment, wherein an angle alpha a between a length dimension, of the elongated susceptor elements 3 and the direction of discharge D is in a range between +30 degrees and -30 degrees, in particular +25 degrees and -25 degrees, preferably between +10 degrees and -10 degrees. Accordingly, the elongate susceptor elements 3 may be deposited in a least partial alignment to a projection of the direction of discharge onto a plane defined by the sheet material or onto a plane tangent to the sheet material at a place of deposition. In this case, the angle alpha a is the angle between a length dimension of the elongated susceptor elements 3 and the projection of the direction of discharge onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the place of deposition.

Fig. 2 schematically shows an apparatus 9 according to the present invention in top view. The apparatus 9 comprises a susceptor supply 10 and a fluid medium supply 11 , schematically denoted by a line, coupled to a mixer 12. The mixer 12 is configured for mixing the elongate susceptor elements 3 provided via the susceptor supply 10 with the fluid medium 4 provided via the fluid medium supply 11 and dispersing the elongate susceptor elements 3 in the fluid medium 4. The mixer 12 is coupled via the conduit 8 to at least one convergent applicator nozzle 1. The convergent applicator nozzle 1 is mounted on a beam 13. An aerosol-forming substrate 14 is provided in form of a sheet material 15 to the apparatus 9 below the convergent applicator nozzle 1 and may be conveyed past the convergent applicator nozzle 1 in a conveying direction C. The conveying direction C in the example of Fig.2 is parallel to a plane defined by the sheet material 15 (corresponding to the drawing plane). A projection of the direction of discharge D onto the plane defined by the sheet material 15 is also parallel to the conveying direction C. The convergent applicator nozzle 1 is movably mounted on the beam 13 and is moved transversely across the sheet material 15 in a transverse direction T perpendicular to the conveying direction C, schematically denoted by the double-arrow. The sheet material 15 may be a continuous substrate sheet, as schematically shown in Fig. 2, or a finite substrate sheet. The sheet material 15 may be conveyed in the conveying direction C past the convergent applicator nozzle 1 continuously or stepwise. The movement of the convergent applicator nozzle 1 along the transverse direction T allows for the deposition of the elongate susceptor elements 3 over the whole width of the sheet (which lies in the drawing plane and is perpendicular to the conveying direction C) with a reduced amount of convergent applicator nozzles 1. As an example, one convergent applicator nozzle 1 as shown in Fig. 2 may be provided, wherein the convergent applicator nozzle 1 moves along the transverse direction T over the whole width of the sheet material 15 and is configured for depositing the elongate susceptor elements 3 over the whole width of the sheet material 15. Alternatively, two or more convergent applicator nozzles 1 may be provided mounted on the beam 13, each of the convergent applicator nozzles 1 being movable along the transverse direction T and configured for depositing the elongate susceptor elements 3 on a respective width portion of the sheet material 15. The elongate susceptor elements 3 are therefore discharged in at least a partial alignment and deposited on a main surface of the sheet material 15 in at least partial alignment as shown in Fig. 1A and 1 B.

Fig. 3 schematically shows another example of an apparatus 19 according to the present invention in top view. The apparatus 19 comprises the susceptor supply 10 and the fluid medium supply 11 coupled to the mixer 12. The mixer 12 is configured for mixing the elongate susceptor elements 3 provided via the susceptor supply 10 with the fluid medium 4 provided via the fluid medium supply 11 and dispersing the elongate susceptor elements 3 in the fluid medium 4. The mixer 12 is coupled via the conduit 8 to the al least one convergent applicator nozzle 1. The convergent applicator nozzle 1 is mounted on the beam 13. The aerosol-forming substrate 14 is provided in form of a sheet material 15 to the apparatus 19 below the convergent applicator nozzle 1 and may be conveyed past the convergent applicator nozzle in the conveying direction C. The conveying direction C in the example of Fig.3 is parallel to a plane defined by the sheet material 15 (corresponding to the drawing plane). The convergent applicator nozzle 1 is movably mounted on the beam 13 and oscillates in a pendulum movement P, schematically denoted by the doublearrow, around a pendulum axis 16. The pendulum axis 16 is arranged perpendicular to the plane defined by the sheet material 15. The direction of discharge D is perpendicular to the pendulum axis 16. The sheet material 15 may be a continuous substrate sheet, as schematically shown in Fig. 3, or a finite substrate sheet. The sheet material 15 may be conveyed in the conveying direction C past the convergent applicator nozzle 1 continuously or stepwise. Alternatively, two or more convergent applicator nozzles 1 may be provided mounted on the beam 13, each of the convergent applicator nozzles 1 being movable around a pendulum axis 16 in a pendulum movement P and configured for depositing the elongate susceptor elements 3 on a respective width portion of the sheet material 15. Alternatively or additionally, two or more convergent applicator nozzles 1 may have a common pendulum axis 16 and may be moved around the common pendulum axis 16 in a pendulum movement P. The elongate susceptor elements 3 are therefore discharged in at least a partial alignment and deposited on a main surface of the sheet material 15 in at least partial alignment as shown in Fig. 1A and 1 B.

The transverse movement of the at least one convergent applicator nozzle 1 across the sheet material 15 in the transverse direction T, as shown in Fig. 2, and the pendulum movement P around the pendulum axis 16 may be combined, as shown schematically in Fig. 4 with one convergent applicator nozzle 1 . Configurations with more than one convergent applicator nozzle 1 , as described with respect to Figs. 2 and 3, may be also possible. In the case where a plurality of convergent applicator nozzles 1 are comprised by the apparatus, each of the convergent applicator nozzles 1 may be moved around a respective pendulum axis 16 in a pendulum movement P. Alternatively or additionally, two or more convergent applicator nozzles 1 may have a common pendulum axis 16 and may be moved around the common pendulum axis 16 in a pendulum movement P. In the example Figs, 2, 3 and 4 with a plurality of convergent applicator nozzles 1 , the beam 13 may be moved around the pendulum axis 16 in the pendulum movement P, therefore moving the plurality of convergent applicator nozzles 1 around a common pendulum axis 16.

Fig 5 shows another example of an apparatus 29 according to the present invention in top view. The apparatus 29 comprises the susceptor supply 10 and the fluid medium supply 11 coupled to the mixer 12. The mixer 12 is configured for mixing the elongate susceptor elements 3 provided via the susceptor supply 10 with the fluid medium 4 provided via the fluid medium supply 11 and dispersing the elongate susceptor elements 3 in the fluid medium 4. The mixer 12 is coupled via the conduit 8 to a plurality of convergent applicator nozzles 1. The convergent applicator nozzles 1 are mounted on the beam 13 with their respective direction of discharge D arranged parallel to each other. An aerosol-forming substrate 14 is provided in the form of a sheet material 15 to the apparatus 29 below the convergent applicator nozzle 1 and may be conveyed past the convergent applicator nozzle in a conveying direction C. The conveying direction C in the example of Fig.5 is parallel to a plane defined by the sheet material 15 (corresponding to the drawing plane). A projection of the direction of discharge D onto the plane defined by the sheet material 15 is also parallel to the conveying direction C. The sheet material 15 may be a continuous substrate sheet, as schematically shown in Fig. 5, or a finite substrate sheet. The sheet material 15 may be conveyed in the conveying direction C past the convergent applicator nozzle 1 continuously or stepwise. Providing a plurality of convergent applicator nozzles 1 , as shown in Fig. 5, allows for the deposition of the elongate susceptor elements 3 over the whole width of the sheet material 15 without the need of providing movement of the convergent applicator nozzle(s) 1 as shown in Figs. 2, 3 and 4. Such a combination is however possible. The elongate susceptor elements 3 are therefore discharged in at least a partial alignment and deposited on a main surface of the sheet material 15 in at least partial alignment as shown in Fig. 1A and 1 B.

Additionally or alternatively, the beam 13 may be moved relative to the sheet material 15. In the examples shown in Figs. 2, 3 4 and 5, the beam 13 may be moved in a beam direction parallel to the conveying direction C, even in the case where the sheet material 15 is not conveyed, as shown schematically by the double arrow B.

In Fig. 6, a schematic, simplified lateral view of an apparatus according to the present invention is shown. The apparatus of Fig. 6 may be constructed according to the apparatuses 9, 19 and 29 of Figs 2, 3, 4 and 5. The at least one convergent applicator nozzle 1 is arranged above the sheet material 15 on the beam 13. The sheet material 15 is conveyed in the conveying direction C parallel to a plane defined by the sheet material 15. The sheet material 15 may be conveyed by means or one or more rollers 17 and/or one or more conveyor belts 18 in the conveying direction C, either continuously or stepwise. The convergent applicator nozzle 1 is arranged at an angle 20 between the direction of discharge D and the plane of the sheet material 15. Preferably, the angle 20 is in a range between 0 degrees and 90 degrees, more preferred between 0 and 80 degrees, and even more preferred between 0 degrees and 45 degrees.

In Fig. 7, a schematic, simplified lateral view of an apparatus according to the present invention is shown. The apparatus of Fig. 7 may be constructed according to the apparatuses 9, 19 and 29 of Figs 2, 3, 4 and 5. The at least one convergent applicator nozzle 1 is arranged above the sheet material 15 on the beam 13. The sheet material 15 is conveyed in the conveying direction C parallel to a plane 21 tangent to the sheet material 15 at a place of deposition 22. The sheet material 15 may be conveyed by means or one or more rollers 17 and/or one or more conveyor belts 18 in the conveying direction C, either continuously or stepwise. The convergent applicator nozzle 1 is arranged at an angle 20 between the direction of discharge D and the plane 21 tangent to the sheet material 15 at the place of deposition 22. Preferably, the angle 20 is in a range between 0 degrees and 90 degrees, more preferred between 0 and 80 degrees, and even more preferred between 0 degrees and 45 degrees.

In Fig. 8, a flow chart of a method according to the present invention is shown. The method of applying elongate susceptor elements 3 to an aerosol-forming substrate 14 for use in an inductively heatable aerosol-generating article according to the present invention may be performed with an apparatus according to the present invention, as described above.

In a first step 23, an aerosol-forming substrate 14 is provided in the form of a sheet material 15. In a second step 24, elongate susceptor elements 3 are provided. The elongate susceptor elements 3 provided in step 24 are then dispersed in a fluid medium 4 in a subsequent step 25. In step 26, the elongate susceptor elements 3 dispersed in the fluid medium 4 provided in step 25 are passed through an applicator comprising at least one convergent applicator nozzle 1. Passing through the at least one convergent applicator nozzle 1 , as described above, causes the elongate susceptor elements 3 dispersed in the fluid medium 4 to be discharged from the at least one convergent applicator nozzle 1 in at least partial alignment along a direction of discharge D of the at least one convergent applicator nozzle. The elongate susceptor elements 3 dispersed in the fluid medium 4, discharged from the at least one convergent applicator nozzle 1 in at least partial alignment in step 26 are then deposited, in step 27, on a main surface of the sheet material 15, in at least partial alignment.

Fig. 9 shows a perspective view of a portion of a substrate element 110 forming part of a rod-shaped aerosol-generating article, including a detailed view (bottom right) of its inner structure, in particular the structure of aerosol-forming substrate 14 and the elongate susceptor elements 3. As can be seen from both, the perspective view and the detailed view, the aerosolforming substrate 14 is made from a sheet material 15 that has been gathered into the cylindrical shape the substrate element 110 upon having deposited elongate susceptor elements 2 thereon. For example, the aerosol-forming substrate 14 may be made from a crimped tobacco sheet comprising a tobacco material, organic fibers, a binder, an aerosol former. As can be further seen from the detailed view, the elongate susceptor elements 3 are deposited on the main surface of the sheet material 15 which can be still observed even though the sheet material 15 is crimped and gathered. This may be the result of a manufacturing process including the deposition of the susceptor elements 3 on a main surface of the sheet material 15 according to the present invention, either during a primary process, in which the sheet material 15 is produced, or during a secondary process, where the sheet material 15 is machined. The elongate susceptor elements 3 within the substrate element 110 are all aligned along their length dimension (predominant dimension) substantially in parallel with a pre-defined reference axis of the aerosol-generating article, here the length axis 101 of the article, which is 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 susceptor elements 3, for example when the aerosol-generating article is engaged with an aerosol-generating device providing the alternating magnetic field. As mentioned before, the heating efficiency is at maximum if the elongate susceptor elements 3 are all aligned in parallel to the orientation M of the alternating magnetic field.

For the purpose of the present description and of the appended claims, except where 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 therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1 . A method of applying elongate susceptor elements to 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;

- providing elongate susceptor elements;

- dispersing the elongate susceptor elements in a fluid medium;

- supplying the elongate susceptor elements dispersed in the fluid medium to and passing them through an applicator comprising at least one convergent applicator nozzle causing the elongate susceptor elements dispersed in the fluid medium to be discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle;

- depositing the elongate susceptor elements dispersed in the fluid medium, being discharged from the at least one convergent applicator nozzle in at least partial alignment, on a main surface of the sheet material.

2. The method according to claim 1 , wherein the at least partial alignment is such that an angle between a length dimension of the elongate susceptor elements and the direction of discharge is in a range between +30 degrees and -30 degrees, in particular +25 degrees and -25 degrees, more particularly between +10 degrees and -10 degrees.

3. The method according to claim 1 , wherein the elongate susceptor elements dispersed in the fluid medium are discharged from the at least one convergent applicator nozzle in substantially parallel alignment to each other and to the direction of discharge.

4. The method according to any one of the preceding claims, wherein during depositing the elongate susceptor elements dispersed in the fluid medium on the main surface of the sheet material, the sheet material is moved relative to (in particular past) the at least one convergent applicator nozzle in a conveying direction, the conveying direction preferably being parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at a place of deposition.

5. The method according to any one of the preceding claims, wherein a transverse dimension of a minimum cross-sectional area of the at least one convergent applicator nozzle is in a range between 0.5 and 1.5, in particular between 0.75 and 1.25, preferably between 0.9 and 1.1 times a mean length dimension of the elongate susceptor elements.

6. The method according to any one of the preceding claims, wherein the aerosol-forming substrate is made from a substrate slurry casted into the form of the sheet material, wherein the elongate susceptor elements are deposited on the casted substrate slurry.

7. The method according to claim 6, wherein the elongate susceptor elements are deposited on the main surface of the sheet material prior to drying the casted substrate slurry.

8. The 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.

9. The method according to any one of claims 1 to 5, wherein the aerosol-forming substrate in the form of the sheet material is a continuous substrate sheet, and wherein the elongate susceptor elements are deposited on the main surface of the sheet material after crimping the continuous substrate sheet, especially after crimping the continuous substrate sheet in a longitudinal direction, in particular in a machine direction of the continuous substrate sheet.

10. The method according to any one of the preceding claims, wherein the elongate susceptor elements have a greater extent in a length dimension than in the two transverse dimensions, and wherein an aspect ratio of a maximum extent of the elongate susceptor elements in the length dimension to a maximum extent of the elongate susceptor elements in the transverse dimensions 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.

11 . The method according to any one of the preceding claims, wherein the aspect ratio of the maximum extent of the elongate susceptor elements in the length dimension to the maximum extent in the transverse dimensions is in a range between 4 and 500, in particular between 10 and 300, preferably between 20 and 200, more preferably between 30 and 100.

12. The method according to any one of the preceding claims, wherein the maximum extent of the elongate susceptor elements in the length dimension is in a range between 20 micrometer and 50 millimeter, in particular 100 micrometer and 16 millimeter, preferably between 0.5 millimeter and 5 millimeter.

13. The method according to any one of the preceding claims, wherein the maximum extent of the elongate susceptor elements in the transverse dimensions is a range between 5 micrometer and 500 micrometer, in particular 10 micrometer and 150 micrometer, preferably 80 micrometer and 120 micrometer.

14. The method according to any one of the preceding claims, wherein the maximum extent of the elongate susceptor elements in the transverse dimensions is equal to or smaller than 500 micrometer, in particular 100 micrometer, preferably 50 micrometer, more preferably 25 micrometer.

15. An apparatus for applying elongate susceptor elements to an aerosol-forming substrate, in particular for use in a method according to any one of the preceding claims, the apparatus comprising: a susceptor supply for providing the elongate susceptor elements; a fluid medium supply for providing a fluid medium; a mixer coupled to the susceptor supply and the fluid medium supply for dispersing the elongate susceptor elements in the fluid medium; an applicator comprising at least one convergent applicator nozzle which is configured such that the elongate susceptor elements dispersed in the fluid medium are discharged from the at least one convergent applicator nozzle in at least partial alignment along a direction of discharge of the at least one convergent applicator nozzle.

16. The apparatus according to claim 15, further comprising a substrate supply for providing an aerosol-forming substrate in the form of a sheet material to or past the at least one convergent applicator nozzle, enabling the at least one convergent applicator nozzle to deposit the elongate susceptor elements dispersed in the fluid medium in at least partial alignment on the main surface of the sheet material.

17. The apparatus according to claim 15 or 16, wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane defined by the sheet material when being provided to or past the convergent applicator nozzle is in a range between 0 degrees and 80 degrees, or wherein an angle between the direction of discharge of the at least one convergent applicator nozzle and a plane tangent to the sheet material at a place of deposition when being provided to or past the convergent applicator nozzle is in a range between 0 degrees and 80 degrees.