Method and apparatus for applying elongated susceptor elements to an aerosol-forming substrate - Patent Application 20070122997

Abstract

The present invention relates to a method and apparatus (9) for applying elongated susceptor elements (3) 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 (15), providing elongated susceptor elements (3), feeding the elongated susceptor elements (3) to and passing them through a screening device (1) comprising a screen (4) having a plurality of elongated screen openings (5) arranged parallel to their longitudinal axes along an alignment axis of the screen (4), and depositing the elongated susceptor elements (3) that have exited the screen (4) in at least partial alignment on a major surface of the sheet material (15), preferably under the influence of gravity.

Description

[Technical Field]

[0001] The present disclosure relates to a method for applying elongated susceptor elements to an aerosol-forming substrate for use in an inductively heatable aerosol-generating article. The present disclosure further relates to an apparatus for applying elongated susceptor elements to an aerosol-forming substrate, particularly for use in a method according to the present disclosure. [Background technology]

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

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

[0004] It would therefore be desirable to have an inductively heatable aerosol-forming substrate and an apparatus for producing such an aerosol-forming substrate that has the advantages of the prior art solutions but reduces their limitations, and in particular, it would be desirable to have an aerosol-forming substrate that provides for more efficient heating and utilization of the aerosol-forming substrate. Summary of the Invention

[0005] According to one aspect of the present disclosure, a method for applying elongated susceptor elements to an aerosol-forming substrate for use in an inductively heatable aerosol-generating article is provided. The method includes providing an aerosol-forming substrate in the form of a sheet material and providing elongated susceptor elements. The provided elongated susceptor elements are then fed into a screening device including a screen having a plurality of elongated screen openings arranged parallel to their longitudinal axes along the screen's alignment axis, and then pass through the plurality of elongated screen openings. The elongated susceptor elements then exit the screen at least partially aligned and are deposited on a major surface of the sheet material, particularly under the influence of gravity. The sheet material may be provided as a finite sheet material or as a continuous substrate sheet. The screen thus functions as a sieve, and depending on the dimensions and orientation of the elongated screen openings, only elongated susceptor elements within a given alignment range can pass through the screen and are consequently exited at least partially aligned on the major surface of the sheet material.

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

[0007] Although the present invention is described herein with respect to elongated susceptor elements having a length dimension greater than any transverse dimension perpendicular to the length dimension, i.e., 1D-elongated susceptor elements greater in one major dimension than in two remaining dimensions perpendicular to the major dimension, this definition equally applies to susceptor elements having two (perpendicular) major dimensions greater than the remaining dimensions perpendicular to the major dimension. Such susceptor elements may also be referred to as 2D-elongated susceptor elements. In particular, the present invention equally applies to susceptor elements having a width dimension greater than the length and thickness dimensions, and the length dimension may be greater than or substantially similar to the width dimension. More specifically, the present invention equally applies to susceptor elements having one of the following shapes: an obtuse cylindrical shape, such as a coin shape, an obtuse elliptical shape, such as a lens shape, or a flake or plate shape. For these susceptor elements, the same features and advantages described herein with respect to (1D-) elongated susceptor elements apply equally and can essentially be expressed similarly by replacing the term "maximum length dimension of the (1D-) elongated susceptor element" with "maximum dimension in the two major dimensions of the 2D-elongated susceptor element" and "maximum transverse dimension of the (1D-) elongated susceptor element" with "maximum dimension in the remaining (non-major) direction of the 2D-elongated susceptor element".

[0008] Compared to a single solid susceptor element, the use of multiple elongated susceptor elements distributed throughout the aerosol-forming substrate advantageously results in a more uniform heat distribution across the substrate without any significant temperature gradients across different substrate regions. Furthermore, if the susceptor material of the susceptor elements has a high thermal conductivity, the uniformity of the heat distribution is further enhanced by the fact that a substrate containing multiple susceptor elements distributed therein exhibits an increased equivalent thermal conductivity compared to a substrate without susceptor elements or having only a single solid susceptor element. Furthermore, to achieve a uniform heat distribution, the proposed susceptor arrangement is less sensitive to the positioning of the susceptor elements compared to a single solid susceptor element.

[0009] Most importantly, it has been found that the geometry of the susceptor element, particularly its relative dimensions, has a significant impact on heating efficiency and, therefore, substrate extraction efficiency. In this regard, it has been found that susceptor elements with elongated shapes are less prone to demagnetization effects than susceptor elements with more equidimensional dimensions, such as spherical or quasi-spherical susceptor particles. This can be explained as follows: When a susceptor element is placed in an external magnetic field, it is progressively magnetized. As the external magnetic field increases, the internal magnetization also increases. This process continues until the magnetization reaches the magnetic saturation point of the material, beyond which no further magnetization occurs. As a result, the magnetization of the susceptor element causes a buildup of magnetic charge density at both ends of the susceptor element, as seen in the direction of the external magnetic field. As a result, the susceptor element generates a magnetic field that causes self-interaction with the material. This magnetic field is along the same direction as the external magnetic field but at a point opposite to it, and is therefore called a demagnetizing field. The demagnetization field depends on the geometry of the susceptor element but not its absolute dimensions. When a susceptor element responds to an external magnetic field change, the demagnetization field is generally assumed to be proportional to the magnetization in each direction, related by a geometrically dependent proportionality constant known as the demagnetization factor. The demagnetization factor depends not only on the shape of the susceptor element but also on its relative orientation with respect to the external magnetic field. To this extent, it has been found that an external magnetic field running through an elongated susceptor element, such as a susceptor element having the shape of a fiber or thin rod with a length dimension significantly greater than any transverse dimension perpendicular to the length dimension, generates a weak or negligible demagnetization field compared to a non-elongated (similarly sized) susceptor element, such as a spherical or quasi-spherical susceptor element. This is intuitively understandable, since in properly aligned elongated susceptor elements, the magnetic charge densities accumulated at both ends of the susceptor element are spatially separated from each other. This causes the demagnetizing field to have a significantly reduced strength and therefore less effect on the magnetizing field, which is the source of power loss. As a result, power loss and therefore heating efficiency is greater in elongated susceptor elements compared to non-elongated (of equal dimensions) susceptor elements, such as spherical or quasi-spherical susceptor elements.This is especially true when the magnetic field orientation is substantially parallel to the length dimension of the elongated susceptor elements, and in this configuration, heating performance is maximized. However, it has been found that the elongated susceptor elements do not necessarily need to be aligned perfectly parallel to the external magnetic field direction. Even if the susceptor elements are arranged at a certain range of angles relative to the orientation of the external magnetic field, the overall heating performance will still be higher than a susceptor arrangement in which the susceptor elements are randomly oriented.

[0010] Because the overall heating performance of the elongated susceptor elements increases as the deviation from an alignment substantially parallel to the alternating magnetic field used for induction heating decreases, the elongated susceptor elements may preferably be aligned such that the angle between the length dimension of the elongated susceptor elements and the alignment axis of the screen is within the range of +30° to −30°, preferably +25° to −25°, and specifically +10° to −10°. Accordingly, the elongated susceptor elements may be deposited on a major surface of the sheet material in a similar alignment, thereby increasing heating performance. As used herein, the terms “(at least) partially aligned” or “(at least) partially aligned” refer to this type of alignment in the angular range defined above.

[0011] As mentioned above, heating performance is maximized with a substantially parallel alignment. Therefore, the elongated susceptor elements preferably exit the screen substantially parallel to the screen's alignment axis. As used herein, the term "substantially parallel" is understood to mean "a deviation of ±5° from parallel orientation."

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

[0013] In the method / apparatus according to the present disclosure, a method / apparatus is provided that allows elongated susceptor elements to be at least partially aligned prior to deposition thereof, such that the at least partially aligned elongated susceptor elements can be ejected at least partially aligned and deposited on a major surface of a sheet material at least partially aligned.

[0014] In the present disclosure, whenever a number or range is given for a plurality of objects, such as a plurality of susceptor elements, this means that the number or range applies to at least 60 percent, particularly at least 70 percent, more particularly at least 80 percent, and particularly at least 90 percent of the plurality of objects, and preferably all of the plurality of objects. For example, the present disclosure states that the elongated susceptor elements are aligned such that the angle between the length dimension of the elongated susceptor element and the alignment axis of the screen is within a range of +A degrees to -A degrees, which means that at least 60 percent, particularly at least 70 percent, more particularly at least 80 percent, and particularly at least 90 percent of all elongated susceptor elements are aligned such that the angle between the length dimension of the elongated susceptor element and the alignment axis of the screen is within a range of +A degrees to -A degrees.

[0015] In order to discharge the elongated susceptor elements on the main surface of the sheet material, in particular by gravity alone, a screen may preferably be arranged vertically above the sheet material at the deposition location on the main surface.

[0016] As used herein, the term "vertically disposed above" is understood to be in the projection of a plane of the sheet material or in the projection of a plane tangent to the sheet material at the deposition location above the sheet material.

[0017] As used herein, the term "deposition site" refers to the current surface portion of the sheet material on which the elongated susceptor elements are deposited at a given time during the ejection and deposition process on a major surface of the sheet material.

[0018] By providing a screen positioned vertically above the sheet material, the elongated susceptor elements can be simply deposited by gravity onto a major surface of the sheet material.

[0019] In order to deposit the elongated susceptor elements onto a large surface area of ​​the sheet material, the screen and the sheet material may be moved relative to one another during deposition of the elongated susceptor elements onto a major surface of the sheet material, which is particularly advantageous when the sheet material is provided as a continuous substrate sheet.

[0020] In particular, during the deposition of the elongate susceptor elements onto a major surface of the sheet material, the sheet material may be moved continuously or stepwise relative to (in particular through) the screen in a conveying direction, which is preferably parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at the deposition location.

[0021] In order to provide optimal alignment of the elongated susceptor elements on the major surface of the sheet material, the projection of the alignment axis of the screen onto a plane defined by the sheet material or onto a plane tangent to the sheet material at the deposition location may be substantially parallel to the conveying direction.

[0022] In a preferred arrangement, the alignment axis of the screen may be substantially parallel to the transport direction.

[0023] The continuous or stepwise movement of the sheet material relative to (and especially through) the screen in the conveying direction may preferably be achieved by a conveyor belt or by one or more rollers.

[0024] Again, in order to deposit the elongated susceptor elements onto a large surface area of ​​the sheet material, the screen may be moved relative to (in particular across) the sheet material in a transverse direction, preferably perpendicular to the conveying direction, while the elongated susceptor elements are being deposited onto the major surface of the sheet material.

[0025] In particular, to deposit the elongated susceptor elements on a large surface area of ​​the sheet material, the screen may be moved relative to (in particular transverse to) the sheet material in a plane parallel to the plane defined by the sheet material or parallel to the plane tangent to the sheet material at the deposition location while the elongated susceptor elements are being deposited on a major surface of the sheet material. The movement may in particular be in a direction transverse to the alignment axis of the screen and / or parallel to the alignment axis of the screen or parallel to the projection of the alignment axis of the screen onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the deposition location.

[0026] Good performance in terms of alignment of the elongated susceptor elements can be achieved in particular in configurations where the screen is positioned horizontally or inclined along the alignment axis relative to the horizontal, thereby also using gravity for the purpose of aligning and discharging the elongated susceptor elements. The angle of inclination may in particular be in the range of 2° to 45°, preferably 2° to 20°, more preferably 5° to 10°.

[0027] For best results with respect to alignment and discharge of the elongated susceptor elements, the screen may preferably be configured so that the maximum lateral dimension of the elongated screen openings perpendicular to their longitudinal axes is in the range of 0.5 to 1.5 times, in particular 0.75 to 1.25 times, preferably 0.9 to 1.1 times the average linear dimension of the elongated susceptor elements.

[0028] The cross section of the elongated screen opening may have a rectangular, elliptical or oval shape. As used herein, the cross section of the elongated screen opening may be understood as the outline of the elongated screen opening as seen in plan view on the plane of the screen.

[0029] Defined in absolute terms, the maximum lateral dimension of the elongate screen openings perpendicular to the longitudinal axis may be in the range of 0.1 mm to 20 mm, in particular 0.25 mm to 10 mm, preferably 0.5 mm to 5 mm.

[0030] The screening device may preferably be a vibrating screening device, and the screen may accordingly be a vibrating screen. The screening device may preferably include a vibration generator configured to vibrate the screen. The vibration generator may in particular be an ultrasonic vibration generator. A vibrating screen is particularly advantageous for transporting and distributing the elongated susceptor elements onto the screen and for sieving the elongated susceptor elements through the elongated screen openings, which can avoid clogging of the elongated screen openings and increase the throughput of the elongated susceptor elements through the screen.

[0031] This may be further supported by a screening device comprising a brushing member movably arranged relative to the screen over the upstream side of the screen (the side of the screen on which the elongated susceptor elements are provided). The brushing member may be configured to assist the elongated susceptor elements in passing through the elongated screen openings. The brushing element may move randomly on the upstream side of the screen, particularly as a result of vibration of the screen.

[0032] To avoid clogging or solidification of the elongated susceptor elements, the screening device may be configured to avoid electrostatic charging and / or magnetization of the elongated susceptor elements. In particular, the screening device may include or consist of an antistatic and / or diamagnetic material.

[0033] Another possibility for depositing elongated susceptor elements over a large surface area of ​​the sheet material may be the construction of a screen having lateral dimensions that substantially correspond to the lateral dimensions of the sheet material.

[0034] The aerosol-forming substrate may be made from a substrate slurry cast in the form of a sheet material, and the elongated susceptor elements are preferably deposited on the cast substrate slurry, particularly before drying the cast substrate slurry. Depending on the hardness of the cast substrate slurry, the elongated susceptor elements may be at least partially embedded in the substrate sheet after or during deposition.

[0035] As already mentioned above, the aerosol-forming substrate in the form of a sheet material may be a continuous substrate sheet, thus allowing for the continuous deposition of elongated susceptor elements on the continuous substrate sheet.

[0036] To further improve the production of aerosol-forming substrates, elongated susceptor elements may be deposited on a major surface of the sheet material during or after crimping the continuous substrate sheet. In particular, during or after crimping the continuous substrate sheet in the longitudinal direction, which may be the machine direction of the continuous substrate sheet, preferably parallel to the transport direction. Depositing the elongated susceptor elements during or after crimping has the advantage that, because the sheet material is corrugated, the formed corrugations are particularly advantageous for accommodating the elongated susceptor elements during deposition, thereby simplifying deposition and improving alignment and distribution of the elongated susceptor elements.

[0037] To improve retention of the elongated susceptor elements and to avoid displacement of the elongated susceptor elements, an adhesive may be applied to a major surface of the sheet material before depositing the elongated susceptor elements thereon. The adhesive may in particular comprise glycerol.

[0038] As mentioned above, the geometry, particularly the relative dimensions, of the elongated susceptor elements have a significant impact on the heating efficiency and, therefore, the extraction efficiency of the substrate. Therefore, the elongated susceptor elements may be selected so that the ratio of their length dimension to their maximum transverse dimension is greater than 4, particularly greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35. As used herein, the term "maximum transverse dimension" refers to the largest dimension of the elongated susceptor element perpendicular to its major dimension (the length dimension). This ratio may also be referred to as the aspect ratio or form factor.

[0039] As used herein, the ratio of the maximum length dimension of an elongated susceptor element to the maximum transverse dimension of the elongated susceptor element perpendicular to the length dimension is also referred to as the form factor or aspect ratio. Thus, the form factor of an elongated susceptor element is greater than 4, particularly greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35.

[0040] The ratio of the maximum linear dimension to the maximum transverse dimension (form factor) preferably has an upper as well as a lower limit. Thus, the ratio of the maximum linear dimension of an elongated susceptor element to the maximum transverse dimension perpendicular to the (maximum) linear dimension, i.e., the form factor of the elongated susceptor element, may be in the range of 4 to 500, in particular 10 to 300, preferably 20 to 200, and more preferably 30 to 100.

[0041] In absolute values, the length dimension of the elongated susceptor elements may be in the range of 20 micrometers to 50 millimeters, in particular 100 micrometers to 16 millimeters, preferably 0.5 millimeters to 5 millimeters. Such maximum length dimension is advantageous for deposition according to the present disclosure.

[0042] Depending on the respective absolute values ​​of the maximum length dimensions, the respective absolute values ​​of the maximum transverse dimensions of the elongated susceptor elements are advantageously also selected within the preferred ranges defined above, such that the form factor is above the lower limit defined above. Thus, the maximum transverse dimension of the elongated susceptor elements may be in the range of 5 micrometers to 500 micrometers, in particular 10 micrometers to 150 micrometers, and preferably 80 micrometers to 120 micrometers. In particular, the maximum transverse dimension of the elongated susceptor elements may be 500 micrometers or less, in particular 100 micrometers, preferably 50 micrometers, and more preferably 25 micrometers.

[0043] The heating efficiency also depends on the density of the elongated susceptor elements in the aerosol-forming substrate. The higher the density, the greater the heating efficiency. The (volume) density of the elongated susceptor elements in the aerosol-forming substrate is preferably in the range of 0.001 susceptor elements per cubic millimeter to 30 susceptor elements per cubic millimeter, in particular 0.1 susceptor elements per cubic millimeter to 10 susceptor elements per cubic millimeter. Similarly, the mass density of the elongated susceptor elements in the aerosol-forming substrate may be in the range of 0.002 milligrams of susceptor mass per cubic millimeter to 0.3 milligrams of susceptor mass per cubic millimeter, in particular 0.01 milligrams of susceptor mass per cubic millimeter to 0.1 milligrams of susceptor mass per cubic millimeter.

[0044] In general, the susceptor elements may have any elongated geometric shape. In particular, the elongated susceptor elements may have one of a cylindrical shape or an oblong shape. That is, the elongated susceptor elements may have a rod-like shape or a particle-like shape.

[0045] By way of example, the elongated susceptor elements may be fiber elements, in particular chopped or milled fiber elements. As another example, the elongated susceptor elements may be wire elements, or thread elements, or particle elements, or rod elements. Advantageously, the fiber elements, or wire elements, or thread elements, or particle elements, or filament elements, or rod elements are made of an inductively heatable material, such as metal fiber, wire, or thread, which is readily available at low cost.

[0046] As viewed in a plane perpendicular to the length dimension of the elongated susceptor element, the cross-section of the elongated susceptor element may have a circular, oval, elliptical, triangular, rectangular, square, or polygonal shape. If the cross-section is circular, the aforementioned maximum transverse dimension of the elongated susceptor element corresponds to the diameter of the susceptor element, which is greatest along the length dimension of the elongated susceptor element. If the cross-section is oval or elliptical, the aforementioned maximum transverse dimension of the susceptor element corresponds to the length of the semi-major axis of the oval or elliptical cross-section, which is greatest along the length dimension of the elongated susceptor element. If the cross-section is square or generally rectangular, the aforementioned maximum transverse dimension of the susceptor element corresponds to the length of the edge / major edge of the square / rectangular cross-section.

[0047] Generally, the term "susceptor element" as used herein refers to an element comprising a susceptor material capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This may be the result of at least one of hysteresis loss or eddy currents induced in the susceptor material depending on the electrical and magnetic properties of the susceptor material. Hysteresis loss occurs in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains in the material being switched under the influence of the alternating electromagnetic field. Eddy currents may be induced if the susceptor material is electrically conductive. In the case of an electrically conductive ferromagnetic susceptor or an electrically conductive ferrimagnetic susceptor, heat can be generated due to both eddy currents and hysteresis loss.

[0048] Thus, the elongated susceptor elements may generally be electrically conductive and / or either ferromagnetic or ferrimagnetic. In particular, the susceptor material of the elongated susceptor elements may be non-conductive but ferromagnetic or ferrimagnetic. Alternatively, the susceptor material of the elongated susceptor elements may be electrically conductive but neither ferromagnetic nor ferrimagnetic.

[0049] Preferably, the susceptor material of the elongated susceptor elements may comprise or consist of a metal, such as ferritic iron, or stainless steel, in particular grade 410, grade 420, or grade 430 stainless steel, or a ferrimagnetic ceramic.

[0050] In addition to the susceptor material, the elongated susceptor elements further include a ferromagnetic or ferrimagnetic marker material.

[0051] The susceptor material is optimized for heat loss and therefore heating efficiency, while the temperature marker material is a magnetic (ferromagnetic or ferrimagnetic) material chosen to have a Curie temperature that essentially corresponds to a predetermined temperature point in the heating process.

[0052] The temperature marker material may have a Curie temperature of less than 500° C., preferably less than or equal to 400° C., specifically less than or equal to 390° C. For example, the temperature marker material of the elongated susceptor element may have a Curie temperature in the range of 180° C. to 420° C., specifically 210° C. to 380° C., preferably 250° C. to 380° C. The temperature marker material is primarily a functional material that provides a temperature marker by virtue of its Curie temperature, but may also contribute to the induction heating process of the susceptor arrangement.

[0053] The temperature marker material of the elongated susceptor element may comprise or consist of nickel or a nickel alloy.

[0054] The susceptor element may be formed such that the susceptor material is at least partially, and preferably completely, surrounded or covered by the temperature marker material.

[0055] Furthermore, the elongate susceptor elements may comprise an outer protective coating surrounding the susceptor material and, if present, the temperature marker material, which protective coating preferably makes the elongate susceptor elements resistant to external influences, in particular corrosive influences.

[0056] The provided elongated susceptor elements may have substantially the same characteristics, such as susceptor material, maximum dimension, feature ratio, temperature marker material, outer coating, etc. Alternatively, a mixture of elongated susceptor elements having different characteristics may be provided.

[0057] It is also possible for the susceptor material of the susceptor element itself to have the temperature marker function, i.e. the elongate susceptor element may comprise a single material that acts as both susceptor material and temperature marker material.

[0058] The present disclosure also relates to an apparatus for applying elongated susceptor elements to an aerosol-forming substrate. The apparatus may be particularly suitable for use in a method according to the present disclosure. Accordingly, the above description applies accordingly to the apparatus according to the present disclosure.

[0059] The apparatus may comprise a screening device, which itself comprises a screen having a plurality of elongated screen openings arranged parallel to their longitudinal axes along an alignment axis of the screen.

[0060] The elongated susceptor elements may preferably be provided via a susceptor source, which may in particular be a hopper, which may be coupled to a screening device for providing and feeding the elongated susceptor elements.

[0061] Preferably, the aerosol-forming substrate in the form of a sheet material can be provided to or through the screen via a substrate supply, either continuously or stepwise. The sheet material may in particular be provided vertically below the screen, preferably under the influence of gravity, allowing at least partially aligned elongated susceptor elements discharged from the screen to be deposited on a major surface of the sheet material. As used herein, the term "to or through the screen" is understood to mean the downstream side of the screen, i.e., the side of the screen from which the susceptor elements exit the screen as they pass through the elongated screen openings.

[0062] The substrate source may preferably comprise a conveyor belt or one or more rollers for providing, either continuously or in stages, the aerosol-forming substrate in the form of a sheet material passed through a screen in a conveying direction which may preferably be parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at the deposition location.

[0063] For optimal deposition of the elongated susceptor elements onto the sheet material, the screen may preferably be configured and arranged so that the projection of the alignment axis of the screen onto a plane defined by the sheet material or onto a plane tangent to the sheet material at the deposition location is substantially parallel to the conveying direction.

[0064] The screening apparatus may be configured so that the screen is movable relative to (in particular across) the sheet material in a direction transverse, preferably perpendicular, to the conveying direction.

[0065] To further improve the deposition of the elongated susceptor elements onto a large surface area of ​​the sheet material, the screening device may in particular be configured so that the screen is movable relative to (in particular transverse to) the sheet material in a plane parallel to the plane defined by the sheet material or parallel to the plane tangent to the sheet material at the deposition location. The movement may preferably be in a direction transverse to the alignment axis of the screen and / or parallel to the alignment axis of the screen or parallel to the projection of the alignment axis of the screen onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the deposition location.

[0066] In a preferred configuration, the screen may be arranged horizontally along an alignment axis relative to the horizontal or tilted, particularly at an angle of tilt in the range of 2 degrees to 45 degrees, preferably 2 degrees to 20 degrees, more preferably 5 degrees to 10 degrees.

[0067] The maximum lateral dimension of the elongate screen openings perpendicular to their longitudinal axis may be in the range of 0.5 to 1.5 times, in particular 0.75 to 1.25 times, preferably 0.9 to 1.1 times the average length dimension of the elongate susceptor elements.

[0068] The maximum lateral dimension of the elongate screen opening perpendicular to its longitudinal axis may be in the range 0.1 mm to 20 mm, in particular 0.25 mm to 10 mm, preferably 0.5 mm to 5 mm.

[0069] The screening device may in a preferred configuration be a vibrating screening device and the screen may be a vibrating screen.

[0070] The screening device may in particular comprise a vibration generator configured to vibrate the screen, which may preferably be an ultrasonic vibration generator.

[0071] The screening apparatus may further comprise a brushing member movable relative to the screen over an upstream side of the screen, the brushing member configured to assist the elongated susceptor elements in passing through the elongated screen openings.

[0072] To avoid clogging or solidification of the elongated susceptor elements, the screening device may be configured to avoid electrostatic charging and / or magnetization of the elongated susceptor elements. In particular, the screening device may include or consist of an antistatic and / or diamagnetic material.

[0073] Preferably, the lateral dimensions of the screen may substantially correspond to the lateral dimensions of the sheet material.

[0074] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate capable of releasing a volatile compound when heated to form an aerosol. The aerosol-generating article may be a consumable product, particularly a consumable product that is discarded after a single use. For example, the article may be an elongated or rod-shaped article. The elongated or rod-shaped article may have a shape similar to that of a conventional cigarette. Specifically, such an article may have a circular, oval, elliptical, square, rectangular, triangular, or polygonal cross section. As another example, the article may be a cartridge containing a liquid aerosol-forming substrate to be heated.

[0075] As used herein, the term "aerosol-forming substrate" refers to a substrate formed from or including an aerosol-forming material capable of releasing a volatile compound upon heating to generate an aerosol. Preferably, the aerosol-forming substrate is intended to be heated, rather than combusted, to release the aerosol-forming volatile compound. Such a substrate may therefore be referred to as a heat-non-combustion aerosol-forming substrate. Similarly, an aerosol-generating article comprising such an aerosol-forming substrate may also be referred to as a heat-non-combustion aerosol-generating article.

[0076] Generally, the aerosol-forming substrate may include at least one aerosol former and at least one sensory material, both of which are volatilizable when heated. The sensory material may include at least one of a tobacco-containing material, a nicotine-containing material, and a flavoring material. Examples of suitable aerosol formers include glycerin and propylene glycol. Examples of flavoring materials may include plant extracts and natural or artificial flavors.

[0077] The aerosol-forming substrate may be a solid aerosol-forming substrate, a gel-like aerosol-forming substrate, or any combination thereof.

[0078] As mentioned above, the aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. Specifically, the aerosol-forming substrate may comprise a reconstituted tobacco material or a tobacco-containing slurry. Thus, the aerosol-generating article may be a tobacco-containing article. Alternatively, or additionally, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may also comprise other additives and ingredients, such as nicotine or flavoring agents.

[0079] The aerosol-forming substrate may also be a paste-like material, a sachet of porous material containing the aerosol-forming substrate, or loose tobacco mixed with, for example, a gelling or adhesive agent, which may include a common aerosol former such as glycerin, which is compressed or molded into a plug.

[0080] The aerosol-forming substrate is made from a sheet material. For example, the aerosol-forming substrate may be made from a crimped tobacco sheet containing tobacco material, organic fibers, a binder, and an aerosol former. Alternatively, the aerosol-forming substrate may be made from a sheet material containing a nicotine-containing material, organic fibers, a binder, and an aerosol former. As yet another alternative, the aerosol-forming substrate may be made from a sheet material containing tobacco cut filler. In this regard, it has been found that the aerosol-generating article is easy to manufacture, particularly when the susceptor elements are applied to the aerosol-forming substrate when in the form of a sheet material, with respect to the preferred alignment of the elongated susceptor elements with respect to the predefined reference axis of the article. This may be the result of a manufacturing process that includes deposition of the susceptor elements on the outer surface of the sheet material, either during a primary process in which the sheet material is manufactured, or during a secondary process in which the sheet material is machined and combined with other semi-finished products to obtain the final product. As a result, the elongated susceptor elements may ultimately be disposed on the outer surface of the sheet material or may be at least partially embedded in the sheet material near its outer surface, even when the sheet material is subsequently machined, for example, crimped and assembled to form a substrate plug in the final article. [Example]

[0081] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features described above, for example, with any one or more features of other examples, embodiments, or aspects described herein.

[0082] Example 1: A method for applying elongated 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 elongated susceptor elements; feeding the elongated susceptor elements to and passing them through a screening device having a screen having a plurality of elongated screen openings arranged parallel to their longitudinal axes along an alignment axis of the screen; and depositing the elongated susceptor elements emerging from the screen in at least partially aligned state onto a major surface of the sheet material, preferably under the influence of gravity. Example 2: The method of example 1, wherein the at least partial alignment is such that the angle between the length dimension of the elongated susceptor elements and the alignment axis of the screen is in the range of +30 degrees to -30 degrees, preferably +25 degrees to -25 degrees, in particular +10 degrees to -10 degrees. Example 3: The method of example 1, wherein the elongated susceptor elements exiting the screen are aligned substantially parallel to the alignment axis of the screen. Example 4: 4. The method of any one of claims 1 to 3, wherein the screen is disposed vertically above the sheet material at a deposition location on a major surface. Example 5: The method of any one of Examples 1 to 4, wherein the screen and the sheet material are moved relative to one another while the elongated susceptor elements are deposited on the major surfaces of the sheet material. Example 6: 6. The method according to any one of the preceding embodiments, wherein, during the deposition of the elongated susceptor elements onto a main surface of the sheet material, the sheet material is moved relative to (in particular through) the screen in a conveying direction, the conveying direction being preferably parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at the deposition location. Example 7: 7. The method of example 6, wherein the projection of the alignment axis of the screen onto a plane defined by or tangent to the sheet material at the deposition location is substantially parallel to the conveying direction. Example 8: 8. The method of any one of Examples 6 or 7, wherein the alignment axis of the screen is substantially parallel to the conveying direction. Example 9: 9. The method of any one of Examples 6 to 8, wherein the sheet material is moved relative to (in particular through) the screen in the conveying direction by a conveyor belt or by one or more rollers. Example 10: 10. The method according to any one of Examples 6 to 9, wherein the screen is moved relative to (in particular across) the sheet material transversely, preferably perpendicularly, to the conveying direction while the elongated susceptor elements are deposited on the main surface of the sheet material. Example 11: 11. The method according to any one of claims 1 to 10, wherein, during deposition of the elongated susceptor elements on the main surface of the sheet material, the screen is moved relative to (in particular transversely) the sheet material in a plane parallel to a plane defined by the sheet material or a plane tangent to the sheet material at the deposition location, in particular in a direction transverse to the alignment axis of the screen and / or in a direction parallel to the alignment axis of the screen or in a direction parallel to the projection of the alignment axis of the screen onto the plane defined by the sheet material or the plane tangent to the sheet material at the deposition location. Example 12: The method according to any one of Examples 1 to 11, wherein the screen is arranged horizontally along the alignment axis relative to the horizontal or tilted, in particular with a tilt angle in the range of 2° to 45°, preferably 2° to 20°, more preferably 5° to 10°. Example 13: 13. The method according to any one of Examples 1 to 12, wherein the maximum lateral dimension of the elongate screen openings perpendicular to their longitudinal axes is in the range of 0.5 to 1.5 times, in particular 0.75 to 1.25 times, preferably 0.9 to 1.1 times the average length dimension of the elongate susceptor elements. Example 14: 14. The method of any one of Examples 1 to 13, wherein the cross section of the elongated screen opening has a rectangular shape, or an oval shape, or an elliptical shape. Example 15: 15. The method according to any one of Examples 1 to 14, wherein the maximum lateral dimension of the elongate screen openings perpendicular to the longitudinal axis is in the range of 0.1 mm to 20 mm, in particular 0.25 mm to 10 mm, preferably 0.5 mm to 5 mm. Example 16: 16. The method of any one of Examples 1 to 15, wherein the screening apparatus is a vibrating screening apparatus and the screen is a vibrating screen. Example 17: 17. The method according to any one of Examples 1 to 16, wherein the screening apparatus comprises a vibration generator, preferably an ultrasonic vibration generator, configured to vibrate the screen. Example 18: 18. The method of any one of Examples 1 to 17, wherein the screening device comprises a brushing member movable relative to the screen across an upstream side of the screen and configured to assist the elongated susceptor elements in passing through the elongated screen openings. Example 19: 19. The method of any one of embodiments 1 to 18, wherein the lateral dimension of the screen perpendicular to the axis of alignment corresponds substantially to the lateral dimension of the sheet material. Example 20: 20. The method of any one of Examples 1 to 19, wherein the aerosol-forming substrate is made from a substrate slurry cast in the form of a sheet material, and the elongated susceptor elements are deposited on the cast substrate slurry. Example 21: The method of example 20, wherein elongated susceptor elements are deposited on a major surface of the sheet material before drying the cast substrate slurry. Example 22: 22. The method according to any one of embodiments 1 to 21, wherein the aerosol-forming substrate in the form of a sheet material is a continuous substrate sheet. Example 23: The method of Example 22, wherein the elongated susceptor elements are deposited on a major surface of the sheet material during or after crimping the continuous substrate sheet, particularly during or after crimping the continuous substrate sheet in the longitudinal direction, particularly in the machine direction of the continuous substrate sheet. Example 24: The method of any one of Examples 1 to 23, wherein an adhesive is applied to the sheet material before depositing the elongated susceptor elements thereon. Example 25: The method of example 24, wherein the adhesive comprises glycerol. Example 26: The method according to any one of Examples 1 to 25, wherein the ratio of the length dimension to the maximum transverse dimension of the elongated susceptor elements is greater than 4, in particular greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35. Example 27: The method according to any one of Examples 1 to 26, wherein the ratio of the length dimension to the maximum transverse dimension of the elongate susceptor elements is in the range of 4-500, in particular 10-300, preferably 20-200, more preferably 30-100. Example 28: The method according to any one of the preceding embodiments, wherein the length dimension of the elongated susceptor elements is in the range of 20 micrometers to 50 millimeters, in particular 100 micrometers to 16 millimeters, preferably 0.5 millimeters to 5 millimeters. Example 29: The method according to any one of Examples 1 to 28, wherein the maximum transverse dimension of the elongated susceptor elements is in the range of from 5 micrometers to 500 micrometers, in particular from 10 micrometers to 150 micrometers, preferably from 80 micrometers to 120 micrometers. Example 30: The method according to any one of Examples 1 to 29, wherein the elongate susceptor elements have a maximum transverse dimension of 500 micrometers or less, in particular 100 micrometers, preferably 50 micrometers, more preferably 25 micrometers. Example 31: The method of any one of Examples 1-30, wherein the elongated susceptor elements have one of a cylindrical shape or an oblong shape. Example 32: 32. The method according to any one of the preceding embodiments, wherein the elongated susceptor elements are one of fiber elements, in particular chopped or milled fiber elements, or wire elements, or thread elements, or particle elements or rod elements. Example 33: 33. The method of any one of claims 1 to 32, wherein the cross-section of the elongated susceptor element in a plane perpendicular to the length dimension of the susceptor element has a circular shape, or an elliptical shape, or an elliptical shape, or a triangular shape, or a rectangular shape, or a quadrilateral shape, or a polygonal shape. Example 34: 34. The method of any one of embodiments 1-33, wherein the elongated susceptor elements comprise a susceptor material that is electrically conductive and at least one of either ferromagnetic or ferrimagnetic. Example 35: 35. The method of claim 34, wherein the susceptor material of the elongated susceptor elements comprises or consists of a metal, such as ferritic iron, or stainless steel, particularly grade 410, grade 420, or grade 430 stainless steel, or a ferrimagnetic ceramic. Example 36: 36. The method of any one of Examples 34 or 35, wherein the elongated susceptor element further comprises a ferromagnetic or ferrimagnetic temperature marker material in addition to the susceptor material. Example 37: 37. The method of example 36, wherein the temperature marker material of the elongated susceptor element comprises or consists of nickel or a nickel alloy. Example 38: 10. An apparatus for applying elongated susceptor elements to an aerosol-forming substrate, particularly for use in a method according to any one of the preceding claims, the apparatus comprising a screening device comprising a screen having a plurality of elongated screen openings arranged parallel to their longitudinal axes along an alignment axis of the screen. Example 39: 39. The apparatus of example 38, further comprising a susceptor source, particularly a hopper, coupled to the screening apparatus for providing and feeding the screening apparatus. Example 40: 40. An apparatus according to any one of Examples 38 or 39, further comprising a substrate source for providing an aerosol-forming substrate in the form of a sheet material to or through the screen (downstream side of the screen), in particular allowing elongated susceptor elements to be deposited vertically below the screen (downstream side of the screen), and preferably ejected from the screen at least partially aligned on a major surface of the sheet material under the influence of gravity. Example 41: 41. The apparatus of example 40, wherein the substrate source comprises a conveyor belt or one or more rollers for providing an aerosol-forming substrate in the form of a sheet material passing through the screen (downstream of the screen) in a conveying direction, the conveying direction being preferably parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at the deposition location. Example 42: An apparatus as described in Example 41, wherein the screen is configured and arranged so that the projection of the alignment axis of the screen onto a plane defined by the sheet material or onto a plane tangent to the sheet material at the deposition location is substantially parallel to the conveying direction, in particular so that the alignment axis of the screen is substantially parallel to the conveying direction. Example 43: 43. Apparatus according to any one of Examples 41 or 42, wherein the screening device is configured so that the screen is movable relative to (in particular across) the sheet material transversely, preferably perpendicularly, to the conveying direction. Example 44: An apparatus described in any one of Examples 38 to 43, wherein the screening device is configured so that the screen is movable relative to (in particular across) the sheet material in a plane parallel to the plane defined by the sheet material or a plane parallel to the plane tangent to the sheet material at the deposition location, in particular in a direction transverse to the alignment axis of the screen and / or in a direction parallel to the alignment axis of the screen or in a direction parallel to the projection of the alignment axis of the screen onto the plane defined by the sheet material or the plane tangent to the sheet material at the deposition location. Example 45: 45. The apparatus according to any one of Examples 38 to 44, wherein the screen is arranged horizontally or inclined along an aligned axis relative to the horizontal, in particular at an inclination angle in the range of 2° to 45°, preferably 2° to 20°, more preferably 5° to 10°. Example 46: 46. ​​The apparatus according to any one of Examples 38 to 45, wherein the maximum lateral dimension of the elongated screen openings perpendicular to their longitudinal axes is in the range of 0.5 to 1.5 times, in particular 0.75 to 1.25 times, preferably 0.9 to 1.1 times the average length dimension of the elongated susceptor elements. Example 47: 47. An apparatus according to any one of Examples 38 to 46, wherein the maximum lateral dimension of the elongate screen openings perpendicular to the longitudinal axis is in the range of 0.1 mm to 20 mm, in particular 0.25 mm to 10 mm, preferably 0.5 mm to 5 mm. Example 48: 48. The apparatus of any one of Examples 38 to 47, wherein the screening apparatus is a vibrating screening apparatus and the screen is a vibrating screen. Example 49: 49. The apparatus of any one of Examples 38 to 48, wherein the screening apparatus comprises a vibration generator, preferably an ultrasonic vibration generator, configured to vibrate the screen. Example 50: An apparatus described in any one of Examples 38 to 49, wherein the screening device comprises a brushing member movable relative to the screen across the upstream side of the screen and configured to assist the elongated susceptor elements in passing through the elongated screen openings. Example 51: 51. The apparatus of any one of Examples 38 to 50, wherein a lateral dimension of the screen perpendicular to the axis of alignment substantially corresponds to a lateral dimension of the sheet material.

[0083] The embodiments will now be further described with reference to the figures. [Brief explanation of the drawings]

[0084] [Figure 1] Figure 1A shows a schematic top view of a screening device according to the present invention, Figure 1B shows a schematic detail of substantially parallel aligned susceptor elements, and Figure 1C shows a schematic detail of partially aligned susceptor elements. [Figure 2] FIG. 2 shows a schematic top view of an apparatus according to one embodiment of the present invention. [Figure 3] FIG. 3 shows a schematic top view of an apparatus according to another embodiment of the invention. [Figure 4] FIG. 4 shows a schematic side view of an apparatus according to an embodiment of the present invention. [Figure 5] FIG. 5 shows a schematic side view of an apparatus according to another embodiment of the invention. [Figure 6] FIG. 6 shows a schematic flow chart of the method according to the invention. [Figure 7] FIG. 7 shows, in schematic detail, a substrate element comprising an elongated susceptor element.

[0085] All embodiments shown in the figures are schematic and not to scale. DETAILED DESCRIPTION OF THE INVENTION

[0086] In FIG. 1A, an example of a screening apparatus 1 is shown schematically in a top view. A hopper 2 is disposed upstream of the screening apparatus 1 for providing elongated susceptor elements 3 to a screen 4. The screen 4 includes a plurality of elongated screen openings 5, only three of which are provided with reference numerals. The elongated screen openings 5 ​​are arranged parallel to an alignment axis D of the screen 4. The screen 4 is preferably vibrated so that the provided elongated susceptor elements 3 pass through the elongated screen openings 5 ​​of the screen 4 and are discharged therefrom. The screen openings 5 ​​are arranged and configured such that the provided elongated susceptor elements 3 pass through the screen openings in at least partial alignment. The elongated screen openings 5 ​​have a rectangular cross-section, but may also be provided with different shapes, such as oval or elliptical, depending on the shape of the elongated susceptor elements 3.

[0087] 1B, the elongated susceptor elements 3 are discharged in alignment substantially parallel to one another with respect to the alignment axis D of the screen 4 onto a major surface of the aerosol-forming substrate, which is provided as a sheet material. In this case, the elongated susceptor elements 3 may also be deposited substantially parallel to the projection of their longitudinal axis direction D onto a plane defined by the sheet material or onto a plane tangent to the sheet material at the deposition location.

[0088] Alternatively, as shown in detail in FIG. 1C , the elongated susceptor elements 3 may be ejected with at least partial alignment, where the angle alpha (α) between the length dimension of the elongated susceptor elements 3 and the alignment axis D is in the range of +30° to −30°, in particular +25° to −25°, and preferably +10° to −10°, and deposited on a major surface of an aerosol-forming substrate provided as a sheet material. Thus, the elongated susceptor elements 3 may be ejected and deposited at least partially aligned with the projection of the alignment axis D onto a plane defined by the sheet material or a plane tangent to the sheet material at the deposition location. In this case, the angle alpha (α) is the angle between the length dimension of the elongated susceptor elements 3 and the projection of the alignment axis onto the plane defined by the sheet material or a plane tangent to the sheet material at the deposition location.

[0089] FIG. 2 shows a schematic top view of an apparatus 9 according to the present invention. The apparatus 9 comprises a screening apparatus 1 with a screen 4 supplied by a hopper 2 mounted on a beam 13, as shown in FIG. 1. The screen is provided with a plurality of elongated screen openings 5. An aerosol-forming substrate 14 is provided to the apparatus 9 below the screening apparatus 1 in the form of a sheet material 15, which may be conveyed through the screening apparatus 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 withdrawal plane). The projection of the alignment axis D onto the plane defined by the sheet material 15 is also parallel to the conveying direction C. The screening apparatus 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, as shown diagrammatically by a double arrow. The sheet material 15 may be a continuous substrate sheet, as shown diagrammatically in FIG. 2, or a finite substrate sheet. The sheet material 15 may be conveyed continuously or stepwise through the screening device 1 in the conveying direction C. The movement of the screening device 1 along the transverse direction T allows for the deposition of elongated susceptor elements 3 across the entire width of the sheet using a reduced amount of screening device 1 (which is located in the withdrawal plane and perpendicular to the conveying direction C). As an example, one screening device 1 as shown in FIG. 2 may be provided, configured to move along the transverse direction T across the entire width of the sheet material 15 and deposit elongated susceptor elements 3 across the entire width of the sheet material 15. Alternatively, two or more screening devices 1 mounted on the beam 13 may be provided, each of which is movable along the transverse direction T and configured to deposit elongated susceptor elements 3 on a respective width portion of the sheet material 15. The elongated susceptor elements 3 pass through the elongated screen openings 5 ​​and are deposited in at least partial alignment on the major surface of the sheet material 15, as shown in FIGS. 1A, 1B, and 1C.

[0090] FIG. 3 shows a top view of another embodiment of an apparatus 29 according to the invention. The apparatus 29 comprises a screening device 1 with a screen 4 mounted on a beam 13. In the embodiment shown in FIG. 3, the screen 4 has lateral dimensions corresponding to the lateral dimensions of the sheet material 15, meaning that the screen covers the entire width of the sheet material 15. The aerosol-forming substrate 14 is provided in the apparatus 29 below the screening device 1 in the form of a sheet material 15, which may be conveyed through the screening device 1 in a conveying direction C. The conveying direction C in the embodiment of FIG. 3 is parallel to the plane defined by the sheet material 15 (corresponding to the withdrawal plane). The projection of the alignment axis 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 shown schematically in FIG. 3, or a finite substrate sheet. The sheet material 15 may be conveyed in the conveying direction C through the screening device 1 continuously or in stages. As shown in Figure 3, providing a screen 4 having lateral dimensions corresponding to the lateral dimensions of the sheet material 15 allows for the deposition of elongated susceptor elements 3 across the entire width of the sheet material 15 without having to provide for movement of the screening apparatus 1 as shown in Figure 2. However, such combinations are possible. Thus, the elongated susceptor elements 3 are conveyed at least partially aligned towards the discharge end 5 of the guide channel 4 and deposited at least partially aligned on a major surface of the sheet material 15, as shown in Figures 1A and 1B.

[0091] Additionally or alternatively, the beam 13 may be moved relative to the sheet material 15. In the embodiment shown in Figures 2 and 3, the beam 13 may be moved in a beam direction parallel to the conveying direction C, as shown diagrammatically by the double arrow B, even when the sheet material 15 is not being conveyed.

[0092] FIG. 4 shows a schematic, simplified side view of an apparatus according to the present invention. The apparatus of FIG. 4 may be constructed in accordance with the apparatuses 9 and 29 of FIGS. 2 and 3. At least one screening apparatus 1 is disposed above the sheet material 15 on a beam 13. The sheet material 15 is transported in a conveying direction C parallel to a plane defined by the sheet material 15. The sheet material 15 may be transported in the conveying direction C either continuously or stepwise by one or more rollers 17 and / or one or more conveyor belts 18. The screen 4 of the screening apparatus 1 is disposed at an angle 20 between the alignment axis D and the plane of the sheet material 15, which corresponds to the horizontal plane. The angle 20 is preferably in the range of 2 to 45 degrees, more preferably 2 to 20 degrees, and even more preferably 5 to 20 degrees.

[0093] In Figure 5 a schematic and simplified side view of an apparatus according to the invention is shown. The apparatus of Figure 6 may be constructed in accordance with the apparatuses 9 and 29 of Figures 2 and 3. The screen 4 of the screening apparatus 1 is arranged horizontally and parallel to the plane defined by the sheet material 15.

[0094] FIG. 6 shows a flow chart of a method according to the present invention. A method for applying elongated 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 carried out using an apparatus according to the present invention, as described above. In a first step 23, the aerosol-forming substrate 14 is provided in the form of a sheet material 15. In a second step 24, elongated susceptor elements 3 are provided. In a subsequent step 25, the elongated susceptor elements 3 provided in step 24 are then fed to a screening apparatus 1 comprising a screen 4. The screen 4 is provided with a plurality of elongated screen openings 5 ​​arranged parallel to an alignment axis D of the screen 4, and the elongated susceptor elements 3 pass through the elongated screen openings 5. In step 26, the elongated susceptor elements 3 are discharged from the screen 4 in at least partial alignment 4 on a major surface of the sheet material 15, particularly under the influence of gravity.

[0095] FIG. 7 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 internal structure, particularly the structure of the aerosol-forming substrate 14 and the elongated susceptor elements 3. As can be seen from both the perspective view and the detailed view, the aerosol-forming substrate 14 is made from a sheet material 15 that assembles into the cylindrical shape of the substrate element 110 when the elongated susceptor elements are deposited thereon. For example, the aerosol-forming substrate 14 may be made from a crimped tobacco sheet containing tobacco material, organic fibers, a binder, and an aerosol. As can be further seen from the detailed view, the elongated susceptor elements 3 are deposited on a major surface of the sheet material 15, which is still visible even after the sheet material 15 has been crimped and assembled. This may be the result of a manufacturing process according to the present invention that includes deposition of the susceptor elements 3 on a major surface of the sheet material 15, either during a primary process in which the sheet material 15 is manufactured, or during a secondary process in which the sheet material 15 is machined. All of the elongated susceptor elements 3 within the base element 110 are aligned along their length dimension (major dimension) substantially parallel to a predetermined reference axis of the aerosol-generating article, where the length axis 101 of the article is selected to coincide with the direction M of the magnetic field lines of an alternating magnetic field that is used to inductively heat the elongated susceptor elements 3 in use, for example, when the aerosol-generating article is engaged with an aerosol-generating device that provides the alternating magnetic field. As previously mentioned, heating efficiency is maximized when all of the elongated susceptor elements 3 are aligned parallel to the direction M of the alternating magnetic field.

[0096] For purposes of this specification and the appended claims, unless otherwise indicated, all numerical values ​​expressing amounts, quantities, percentages, and the like are to be understood as being modified in all instances by the term "about." Also, all ranges include the maximum and minimum values ​​disclosed, as well as any intermediate ranges contained therein, whether or not specifically recited herein. Thus, in this context, a numerical value A would be understood as A ± 5%. In this context, a numerical value A can be considered to include numerical values ​​that fall within the typical standard error of measurement for the property that A modifies. In some instances, as used in the appended claims, a numerical value A may deviate by the percentages recited above, so long as the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the maximum and minimum values ​​disclosed, as well as any intermediate ranges contained therein, whether or not specifically recited herein.

Claims

1. 1. A method for applying an elongated susceptor element to an aerosol-forming substrate for use in an inductively heatable aerosol-generating article, said method comprising: - providing an aerosol-forming substrate in the form of a sheet material; - providing an elongated susceptor element; - feeding said elongated susceptor elements into and passing through a screening device comprising a screen having a plurality of elongated screen openings arranged parallel to their longitudinal axes along an alignment axis of the screen; depositing, preferably under the influence of gravity, on a major surface of the sheet material, the elongated susceptor elements which exit the screen in at least partial alignment; A method comprising:

2. 2. The method of claim 1, wherein the at least partial alignment is such that an angle between a length dimension of the elongated susceptor elements and the alignment axis of the screen is in the range of +30 degrees to -30 degrees, preferably +25 degrees to -25 degrees, in particular +10 degrees to -10 degrees.

3. The method of claim 1 , wherein the elongated susceptor elements exiting the screen are aligned substantially parallel to the alignment axis of the screen.

4. 4. The method according to claim 1, wherein, during the deposition of the elongated susceptor elements onto the main surface of the sheet material, the sheet material is moved relative to (in particular through) the screen in a conveying direction, the conveying direction being preferably parallel to a plane defined by the sheet material or parallel to a plane tangent to the sheet material at the deposition location.

5. 5. The method of claim 4, wherein the projection of the alignment axis of the screen onto the plane defined by the sheet material or onto the plane tangent to the sheet material at the deposition location is substantially parallel to the conveying direction.

6. 6. The method according to claim 1, wherein the aerosol-forming substrate is made from a substrate slurry cast in the form of a sheet material, and the elongated susceptor elements are deposited on the cast substrate slurry.

7. The method of claim 6 , wherein the elongated susceptor elements are deposited on the major surfaces of the sheet material prior to drying the cast substrate slurry.

8. A method according to any one of claims 1 to 7, wherein the aerosol-forming substrate in the form of a sheet material is a continuous substrate sheet.

9. 6. The method according to any one of claims 1 to 5, wherein the aerosol-forming substrate in the form of a sheet material is a continuous substrate sheet, and the elongated susceptor elements are 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 the longitudinal direction, specifically in the machine direction of the continuous substrate sheet.

10. 10. The method according to any one of claims 1 to 9, wherein the ratio of the length dimension to the largest transverse dimension of the elongated susceptor elements is greater than 4, in particular greater than 10, preferably greater than 20, more preferably greater than 25, even more preferably greater than 30, and most preferably greater than 35.

11. 11. The method according to any one of claims 1 to 10, wherein the ratio of the length dimension to the largest transverse dimension of the elongate susceptor elements is in the range of 4 to 500, in particular 10 to 300, preferably 20 to 200, more preferably 30 to 100.

12. The method according to any one of the preceding claims, wherein the length dimension of the elongated susceptor elements is in the range of 20 micrometers to 50 millimeters, in particular 100 micrometers to 16 millimeters, preferably 0.5 millimeters to 5 millimeters.

13. The method according to any one of the preceding claims, wherein the elongated susceptor elements have a maximum transverse dimension in the range of from 5 micrometers to 500 micrometers, in particular from 10 micrometers to 150 micrometers, preferably from 80 micrometers to 120 micrometers.

14. A method according to any one of the preceding claims, wherein the elongate susceptor elements have a maximum transverse dimension of 500 micrometers or less, in particular 100 micrometers, preferably 50 micrometers, more preferably 25 micrometers.

15. 15. Apparatus for applying elongated susceptor elements to an aerosol-forming substrate, particularly for use in a method according to any one of claims 1 to 14, comprising an aerosol-generating substrate source, an elongated susceptor source, and a screening device comprising a screen having a plurality of elongated screen openings arranged parallel to its longitudinal axis along an alignment axis of the screen.

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