阅读说明：本技术 可感应加热的气溶胶生成制品、用于制造此类制品的方法和用于制造此类制品的感受器的设备 (Inductively heatable aerosol-generating article, method for manufacturing such article and apparatus for manufacturing susceptor for such article ) 是由 R·N·巴蒂斯塔 Y·约迪尔 I·普雷斯蒂亚 于 2020-02-27 设计创作，主要内容包括：本发明涉及一种与感应加热式气溶胶生成装置一起使用的可感应加热的气溶胶生成制品。所述制品包括至少一个气溶胶形成基质和与气溶胶形成基质热接近或与气溶胶形成基质热接触的至少一个感受器。所述感受器包括膨胀金属片,所述膨胀金属片包括穿过所述片的多个开口。本发明还涉及一种用于制造这类可感应加热的气溶胶生成制品的方法。本发明还涉及一种用于制造此类制品的感受器的设备。(The present invention relates to an inductively heatable aerosol-generating article for use with an inductively heated aerosol-generating device. The article comprises at least one aerosol-forming substrate and at least one susceptor in thermal proximity to or in thermal contact with the aerosol-forming substrate. The susceptor comprises an expanded metal sheet comprising a plurality of openings through the sheet. The invention also relates to a method for manufacturing such an inductively heatable aerosol-generating article. The invention also relates to an apparatus for manufacturing a susceptor for such articles.)

1. An inductively heatable aerosol-generating article for use with an inductively heated aerosol-generating device, wherein the article comprises at least one aerosol-forming substrate and at least one susceptor in thermal proximity to or in thermal contact with the aerosol-forming substrate, wherein the susceptor comprises a flattened expanded metal sheet comprising a plurality of openings through the sheet.

2. The article of claim 1, wherein the plurality of openings are arranged in a periodic pattern.

3. The article of any one of the preceding claims, wherein one or more of the plurality of openings have a diamond shape.

4. The article of claim 3, wherein the diamond shape has a first diagonal connecting a first pair of opposing vertices of the diamond shape and a second diagonal connecting a second pair of opposing vertices of the diamond shape, wherein the first diagonal extends in an expansion direction of the expanded metal sheet.

5. The article of claim 4, wherein the first diagonal has a length in a range of 1.7 millimeters to 4.7 millimeters and the second diagonal has a length in a range of 0.3 millimeters to 3.1 millimeters.

6. The article of any one of the preceding claims, wherein one or more of the plurality of openings open laterally toward a side edge of the expanded metal sheet and have a triangular shape.

7. An article according to any preceding claim, wherein the aerosol-forming substrate is arranged at least partially around the susceptor.

8. An article according to any preceding claim, wherein the aerosol-forming substrate comprises non-tobacco plant material.

9. An article according to any preceding claim, wherein the aerosol-forming substrate comprises aerosol former in a proportion by weight in the range 12% to 20% by weight of the aerosol-forming substrate.

10. A method for manufacturing an inductively heatable aerosol-generating article according to any preceding claim, wherein the method comprises the steps of:

-providing an aerosol-forming substrate;

-providing a susceptor comprising an flattened expanded metal sheet comprising a plurality of openings, wherein providing the susceptor comprises the steps of:

-providing a metal sheet;

-creating a plurality of weakened areas in the metal sheet;

-stretching the weakened metal sheet at least in a first direction so as to produce an expanded metal sheet comprising a plurality of openings originating from the plurality of weakened areas; and

-flattening the expanded metal sheet after stretching;

-arranging the susceptor in thermal proximity to or in thermal contact with the aerosol-forming substrate.

11. The method of claim 10, wherein creating the plurality of weakened areas comprises creating a plurality of slits of limited length in the metal sheet, wherein at least a portion of each slit extends along a second direction that is transverse to the first direction.

12. The method of any one of claims 10 or 11, wherein one or more of the plurality of weakened areas may comprise one of: straight slits, curved slits, C-shaped slits, U-shaped slits, sickle-shaped slits, cross-shaped slits or T-shaped slits.

13. A device for manufacturing a susceptor for an aerosol-generating article according to any one of claims 1 to 9, the device comprising:

-a first pair of counter-rotating first rollers, wherein at least one of the first rollers comprises one or more cutting elements arranged on the outer circumferential surface of the respective roller, wherein the one or more cutting elements are configured to create a plurality of weakened areas, in particular a plurality of slits, in the metal sheet when the metal sheet passes between the first pair of first rollers;

-a second pair of counter-rotating second rollers arranged downstream of the first pair of first rollers, the second rollers being configured to convey the weakened metal sheet therebetween at a first conveying speed corresponding to the rotational speed of the second rollers;

-a third pair of counter-rotating third rollers arranged downstream of the second pair of second rollers, the third rollers being configured to convey the weakened metal sheet therebetween at a second conveying speed corresponding to the rotational speed of the third rollers, wherein the rotational speed of the third rollers is higher than the rotational speed of the second rollers, such that the weakened metal sheet, when conveyed by the second and third pairs of rollers, is stretched in the conveying direction, thereby becoming an expanded metal sheet comprising a plurality of openings through the sheet originating from the plurality of weakened areas; and

-a fourth pair of counter-rotating fourth rollers arranged downstream of the third pair of third rollers, the fourth rollers being configured to convey the expanded metal sheet therebetween at a third conveying speed corresponding to the rotational speed of the fourth rollers, wherein the rotational speed of the fourth rollers is higher than the rotational speed of the third rollers, such that the expanded metal sheet is straightened and flattened when conveyed by the third and fourth pairs of rollers.

Technical Field

The present invention relates to an inductively heatable aerosol-generating article for use with an inductively heated aerosol-generating device. The invention also relates to a method for manufacturing such an inductively heatable aerosol-generating article. The invention also relates to an apparatus for manufacturing a susceptor for such articles.

Background

Aerosol-generating articles comprising at least one aerosol-forming substrate capable of forming an inhalable aerosol upon heating are well known. To heat the substrate, the article may be received within an aerosol-generating device comprising an electrical heater. The heater may be an induction heater comprising an induction source. Depending on the electrical and magnetic properties of the susceptor, the induction source is configured to generate an alternating electromagnetic field to inductively heat the susceptor by at least one of eddy currents and hysteresis losses. The susceptor may be an integral part of the article and is arranged in thermal proximity to or in direct physical contact with the substrate to be heated. In operation of the device, volatile compounds are released from the heated aerosol-forming substrate in the article and become entrained in the airflow drawn through the article during the user's draw. As the released compound cools, the compound condenses to form an aerosol.

The susceptor may comprise or may consist of sheet metal. Although such sheet susceptors can be easily manufactured and provide broad thermal emission due to their two-dimensional nature, the overall mass of such susceptors may still generally not be proportional to the thermal emission surface. Therefore, resources are not efficiently utilized.

Accordingly, there would be a need to have an inductively heatable aerosol-generating article and a method for manufacturing such an article that have the advantages of the prior art solutions without their limitations. In particular, there would be a need for inductively heatable aerosol-generating articles and methods for manufacturing such articles with improved resource usage.

Disclosure of Invention

According to the present invention there is provided an inductively heatable aerosol-generating article for use with an inductively heated aerosol-generating device. The article comprises at least one aerosol-forming substrate and at least one susceptor in thermal proximity to or in thermal contact with the aerosol-forming substrate. The susceptor includes an expanded metal sheet including a plurality of openings through the sheet.

As used herein, the term "expanded metal sheet" refers to a type of metal sheet in which a plurality of weakened areas (in particular a plurality of perforations) has been produced and which has subsequently been stretched to form a regular pattern of openings resulting from stretching the plurality of weakened areas (in particular from the plurality of perforations).

The use of a susceptor comprising expanded metal sheets offers a number of advantages compared to other types of sheet-like susceptors.

First, due to the specific manufacturing process, the mass per unit area of the expanded metal sheet is reduced compared to a metal sheet without such openings. At the same time, the surface of the expanded metal sheet is still large enough to provide extensive heat emission. As a result, the ratio of the total mass of the susceptor comprising expanded metal sheet to the heat emitting surface is improved compared to a susceptor comprising metal sheet without any openings. Advantageously, this helps to save resources for manufacturing the article. In addition, the reduced mass per unit area may also be beneficial for a reduced overall mass of the article.

Secondly, the manufacture of expanded metal sheets comprising openings produced as described above (i.e. by weakening, in particular perforating and stretching the metal sheet) advantageously involves no waste of material compared to metal sheets comprising openings produced by material removal, for example by stamping. For this reason as well, the susceptor of the article according to the invention advantageously allows to save materials and production costs, and therefore resources.

Third, due to the openings, the susceptor of the article according to the invention is permeable, so that the air flow drawn through the article is enhanced compared to an article comprising an impermeable susceptor. In addition, the openings of the susceptor promote the release and entrainment of material volatilised from the heated aerosol-forming substrate into the airflow. Advantageously, both aspects promote aerosol formation.

Fourth, the susceptor comprising expanded metal sheets is stronger compared to the equivalent weight of a welded or woven susceptor mesh, since the sheet material, although weakened, in particular perforated and stretched, remains in one piece and thus retains its strength. At the same time, the expanded metal sheet is more flexible and less rigid than a metal sheet without any openings. Advantageously, this facilitates the supply of material during the manufacture of the aerosol-generating article.

Fifth, the openings of the expanded metal sheet may be filled with an aerosol-forming matrix during manufacture of the article. Advantageously, this may support the fixing of the susceptor within the aerosol-forming substrate. Thus, the positional accuracy and stability of the susceptor within the aerosol-forming substrate is significantly improved.

As used herein, the term "sheet" refers to a flat object having an extension in a first direction (in particular, a thickness extension) which is smaller than the extension in a second and third direction, in particular smaller than the width extension and the length extension, in particular at least 5 times smaller, preferably at least 20 times smaller, more preferably at least 50 times smaller, even more preferably at least 100 times smaller, most preferably at least 150 times smaller. Furthermore, the extension of the sheet in the second direction is preferably smaller than the extension of the sheet in the third direction. In particular, the width extension of the sheet may be smaller than the length extension of the sheet.

With regard to the dimensions of the susceptor, the expanded metal sheet may have a thickness extension in the range of 0.05 mm to 0.4 mm, in particular in the range of 0.15 mm to 0.35 mm. Likewise, the expanded metal sheet may have a width extension in the range of 2 to 8mm, in particular in the range of 3 to 6mm, preferably in the range of 4 to 5 mm.

As used herein, the terms "metal sheet" and "expanded metal sheet" refer to a sheet comprising at least one metal or metallic material. As such, the susceptor is electrically conductive and thus inductively heatable at least by eddy currents.

As used herein, the term "opening" is understood to be an opening extending along its thickness from one planar side of the expanded sheet material through the entire expanded sheet material to the opposite planar side. Likewise, the term "perforation" is to be understood as a perforation extending along its thickness from one planar side of the sheet material through the entire sheet material to the opposite planar side. The term "weakened area" refers to an area of the metal sheet having a reduced material thickness extending in a direction perpendicular to the main surface of the metal sheet, i.e. along the thickness of the metal. The reduction in material thickness is such that upon stretching the weakened metal sheet, the weakened area transforms into an opening through the entire expanded sheet material along its thickness extension.

Furthermore, the term "opening" may cover both types of openings, i.e. openings with closed boundaries and openings with partially open boundaries. The opening with the closed boundary is completely delimited along the periphery of the opening by the material of the expanded metal sheet. In contrast, an opening with a partially open boundary is only partially bounded by the material of the expanded metal sheet along the perimeter of the opening. One or more openings having a partially open border, if present, are located at the side edges of the expanded metal sheet. That is, such openings open laterally towards the side edges of the expanded metal sheet. If present, the opening or openings with a partially open border may be created by a weakened area, in particular a perforation, created in the metal sheet, which extends beyond the side edges of the metal sheet and is subsequently stretched.

Thus, the expanded metal sheet may comprise one of the following: a plurality of openings having closed boundaries; a plurality of openings having partially open boundaries; or one or more openings with closed boundaries and one or more openings with partially open boundaries.

The plurality of openings may be arranged in a periodic pattern. The periodic pattern may be advantageous in terms of its manufacture. In particular, the periodic pattern of openings may be achieved by creating a periodic pattern of weakened areas, in particular perforations, in the sheet material and subsequently stretching the weakened, in particular perforated, metal sheet at least in one direction, such that the periodic pattern of weakened areas, in particular perforations, is transformed into a periodic pattern of openings.

The periodic pattern of openings may be a one-dimensional periodic pattern. That is, the periodic pattern may have periodicity only along the first (along one) direction. Preferably, the periodic pattern is a two-dimensional periodic pattern. That is, the periodic pattern may have a periodicity along a first direction and a second direction, wherein the second direction is transverse, in particular perpendicular, to the first direction. In both configurations, the first direction may correspond to the direction of expansion of the expanded sheet material.

The periodic pattern of the plurality of openings may have a periodic length along the first direction in a range of 0.9 millimeters to 7.8 millimeters, preferably in a range of 1.4 millimeters to 4.8 millimeters. Likewise, the periodic pattern of the plurality of openings may have a periodic length along the second direction in a range of 3.4 millimeters to 9 millimeters, preferably in a range of 2.6 millimeters to 5.1 millimeters. Within these ranges, the periodicity along the first and second directions may provide a reasonable ratio between the total mass of the susceptor and the heat emitting surface.

The plurality of openings may be arranged in an offset arrangement, in particular a periodic offset arrangement. Advantageously, the offset arrangement allows a very compact arrangement of the openings, such that the density of openings per unit area is increased, which in turn enables an increase in the permeability of the susceptor and at the same time reduces the total mass per unit area of susceptor material. As mentioned above, the latter allows for more efficient use of resources. In particular, in the offset arrangement, the plurality of openings may be arranged in a plurality of rows along the first direction, wherein each row extends in a second direction perpendicular to the first direction and comprises one or more openings, and wherein one or more openings in one row are offset with respect to one or more openings in each adjacent row. The offset arrangement of the openings may be achieved by creating a corresponding offset arrangement of weakened areas, in particular perforations, wherein the plurality of weakened areas, in particular perforations, may be arranged in a plurality of rows along a first direction, wherein each row extends in a second direction perpendicular to the first direction and comprises one or more weakened areas, in particular perforations, and wherein one or more weakened areas, in particular perforations, in one row is offset with respect to one or more weakened areas, in particular perforations, in each adjacent row.

In general, the shape of the opening may depend on the manufacture of the expanded metal sheet, in particular on the shape of the weakened areas, e.g. perforations, in the metal sheet, and on the direction of expansion in which the weakened, e.g. perforated, metal sheet stretches in order to create the opening. As used herein, the term "shape of the opening" refers to the (cross-sectional) shape of the opening, as seen in a direction perpendicular to the main (planar) surface of the expanded metal sheet, i.e. along the direction of minimum extension of the expanded metal sheet, which is the thickness extension of the expanded metal sheet.

Preferably, one or more of the plurality of openings may have a diamond shape. Diamond shaped openings may be advantageous because they are easy to manufacture, in particular by creating straight slits of limited length in the metal sheet and subsequently by stretching the slit metal sheet in a direction extending transversely, in particular perpendicularly, to the length of the straight slits, which causes each slit to become a diamond shaped opening.

The diamond shape has a first diagonal connecting a first pair of opposing vertices of the diamond shape and a second diagonal connecting a second pair of opposing vertices of the diamond shape. Preferably, the first diagonal line extends in a first direction, which corresponds to an expansion direction of the expanded metal sheet. This can be easily achieved by stretching the metal sheet in a direction perpendicular to the longitudinal extension of the straight slits.

Preferably, the length of the second diagonal is greater than the length of the first diagonal, in particular in case the first diagonal corresponds to the expansion direction of the expanded metal sheet. The above configuration advantageously allows a reduction in the degree of expansion compared to a diamond shaped opening having the same opening area but equal diagonal lines, which makes the manufacture of the expanded metal sheet easier.

The length of the first diagonal may be in the range of 0.3 mm to 3.1 mm, preferably in the range of 0.5 mm to 2.5 mm. Likewise, the length of the second diagonal is in the range of 1.1 mm to 4.7 mm, preferably in the range of 1.7 mm to 3.1 mm.

Likewise, the length of the second diagonal may be in the range of 10% to 60%, in particular 20% to 50%, preferably 30% to 45% of the width extension of the expanded metal sheet.

If one or more of the aforementioned straight slits extend beyond the edge of the metal sheet, the stretching of such slits creates an opening with a partially open border as described above and in particular of triangular shape. In this connection, it should be noted that the partially open portions of the boundaries of the openings correspond to one of the edges of the triangular or triangular shape, respectively. Thus, one or more of the plurality of openings may open laterally towards the side edges of the expanded metal sheet and may have a triangular shape.

Preferably, the aforementioned straight slits extend in a direction perpendicular to the side edges of the metal sheet from which the expanded metal sheet is made, as described in more detail below. In particular, the slits may extend in a direction perpendicular to the length extension of the metal sheet from which the expanded metal sheet is made. The length extension of the metal sheet preferably corresponds to the expansion direction of the expanded metal sheet. Alternatively, the slits may extend at an angle in the range of 5 to 85 degrees, in particular 20 to 70 degrees, preferably 30 to 60 degrees, for example 45 degrees, with respect to the side edges or length of the metal sheet. Stretching these slits in a direction extending parallel to the side edges or length of the expanded metal sheet may result in a three-dimensional configuration of the expanded metal sheet having raised portions protruding in a direction perpendicular to the major (planar) surface of the expanded metal sheet. Advantageously, such elevated portions may support the fixing of the susceptor within the aerosol-forming substrate. The raised portion may be flattened if desired. That is, the susceptor may comprise a flattened expanded metal sheet comprising a plurality of openings through the sheet. In particular, the susceptor may comprise a flattened expanded metal sheet comprising a plurality of openings through the sheet and having no raised portions projecting in a direction perpendicular to a major planar surface of the expanded metal sheet.

The expanded metal sheet of the susceptor may be strip-shaped. As used herein, the term "strip-like" refers to the shape of an element having both a length extension and a width extension greater than a thickness extension. In addition, the length extension is preferably greater than the width dimension. The thickness extension may be in the range of 0.05 mm to 0.4 mm, in particular in the range of 0.15 mm to 0.35 mm. Likewise, the width extension may be in the range of 2 to 8mm, in particular in the range of 3 to 6mm, preferably in the range of 4 to 5 mm. Preferably, the strip-shaped expanded metal sheet has a rectangular cross-section, as seen in a plane extending perpendicular to its length. The length extension preferably corresponds to the expansion direction of the expanded metal sheet. A susceptor in the form of a strip or expanded metal sheet is advantageous in that it can be manufactured easily and at low cost.

Preferably, the susceptor consists only of expanded metal sheet, in particular a strip-shaped expanded metal sheet. That is, the susceptor is preferably an expanded metal sheet, in particular a strip-shaped expanded metal sheet.

In general, the term "susceptor" refers to an element comprising a material that can be inductively heated within an alternating electromagnetic field. This may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. In ferromagnetic or ferrimagnetic susceptors, hysteresis losses occur as magnetic domains within the material are switched under the influence of an alternating electromagnetic field. If the susceptor conducts electricity, eddy currents may be induced. In the case of an electrically conductive ferromagnetic susceptor or an electrically conductive ferrimagnetic susceptor, heat may be generated due to both eddy current and hysteresis losses.

In the present invention, the susceptor is inductively heatable at least by eddy currents, since the expanded metal sheet is electrically conductive due to its metallic nature. Thus, the susceptor according to the invention, in particular the expanded metal sheet, comprises at least one electrically conductive material. The conductive material may be paramagnetic. For example, the conductive material may be or may include aluminum. Alternatively, the conductive material may be ferromagnetic. In this case, the susceptor according to the invention can heat up due to both eddy currents and hysteresis losses. For example, the electrically conductive material may be or may comprise ferritic iron, ferromagnetic alloys, in particular ferromagnetic steel, preferably ferromagnetic stainless steel.

Preferred susceptors may be heated to a temperature of between about 40 degrees celsius and about 500 degrees celsius, particularly between about 50 degrees celsius and about 450 degrees celsius, preferably between about 100 degrees celsius and about 400 degrees celsius.

The susceptor may be a multi-material susceptor. In particular, the expanded metal sheet may be a multi-material expanded metal sheet. Thus, the susceptor or expanded metal sheet may comprise at least a first metallic material and a second metallic material, respectively. The first material is preferably optimized with respect to heat losses and thus heating efficiency. For example, the first material may be aluminum, or a ferrous material, such as stainless steel. In contrast, the second material is preferably used as a temperature marker. For this purpose, the second material is preferably ferromagnetic and is selected so as to have a curie temperature corresponding to a predefined heating temperature of the susceptor. At its curie temperature, the magnetic properties of the second material change from ferromagnetic to paramagnetic, with a temporary change in its electrical resistance. Thus, by monitoring the corresponding change in the current drawn by the induction source, it can be detected when the second material has reached its curie temperature, and thus when the predefined heating temperature has been reached. The curie temperature of the second material is preferably below the ignition point of the aerosol-forming substrate of the aerosol-generating article, i.e. preferably below 500 degrees celsius. Suitable materials for the second material may include nickel and certain nickel alloys. Depending on the nature of the impurities, nickel has a curie temperature in the range of about 354 degrees celsius to 360 degrees celsius. A curie temperature in this range is desirable because it is about the same as the temperature to which the susceptor should be heated in order to generate aerosol from the aerosol-forming substrate, but still low enough to avoid local overheating or burning of the substrate.

The susceptor may be a multi-layer susceptor. Also, the expanded metal sheet may be a multilayer expanded metal sheet. In particular, the multilayer susceptor comprises a plurality of layers of expanded metal sheet. The multilayer susceptor or the multilayer expanded metal sheet may comprise a first layer and a second layer, respectively, wherein the first layer comprises a first metallic material and the second layer comprises a second metallic material as previously described. For example, the first layer may comprise or may be made of ferromagnetic stainless steel, wherein at least one side of the first layer comprises a coating as the second layer, which coating may comprise or may be made of nickel or a nickel alloy.

Preferably, the susceptor is dimensionally stable. This means that during the manufacture of the aerosol-forming rod the susceptor remains substantially undeformed, or any deformation of the susceptor required to form the aerosol-forming rod remains elastic, so that when the deforming force is removed, the susceptor returns to its intended shape. For this purpose, the shape and material of the susceptor may be chosen so as to ensure sufficient dimensional stability. Advantageously, this ensures that the originally desired cross-sectional profile is retained throughout the manufacture of the aerosol-forming rod. High dimensional stability reduces variability in product performance. With regard to the forming device according to the invention and as described in further detail below, this means that the forming device is configured such that the susceptor remains substantially undeformed after passing through the forming device. This means that preferably any deformation of the susceptor required to form the continuous rod remains elastic, so that the susceptor returns to its intended shape when the deforming force is removed.

As used herein, the term "aerosol-forming substrate" refers to a substrate formed from or comprising an aerosol-forming material which upon heating is capable of releasing volatile compounds for use in generating an aerosol. The aerosol-forming substrate is intended to be heated, rather than combusted, to release aerosol-forming volatile compounds.

The aerosol-forming substrate may be a solid, paste-like or liquid aerosol-forming substrate. In any of these states, the aerosol-forming substrate may comprise both solid and liquid components.

The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating.

Alternatively or additionally, the aerosol-forming substrate may comprise a non-tobacco material, in particular a non-tobacco plant material, such as a cut plant material or plant expanded fibres or a plant fibre based porous substrate or foam or a combination thereof.

The aerosol-forming substrate may comprise, for example, one or more of a powder, granules, particles, flakes, rods, strips or sheets containing one or more of herbaceous plant leaf, tobacco vein segment, reconstituted tobacco, extruded tobacco and expanded tobacco, and combinations thereof.

The aerosol-forming substrate may also comprise at least one aerosol-former. The at least one aerosol former may be selected from polyols, glycol ethers, polyol esters, esters and fatty acids, and may include one or more of the following compounds: glycerol, erythritol, 1, 3-butanediol, tetraethylene glycol, triethylene glycol, triethyl citrate, propylene carbonate, ethyl laurate, glyceryl triacetate, meso-erythritol, a mixture of glycerol diacetate, diethyl suberate, triethyl citrate, benzyl benzoate, benzyl phenylacetate, ethyl vanillylate, glyceryl tributyrate, lauryl acetate, lauric acid, myristic acid, and propylene glycol.

One or more aerosol-formers may be combined to take advantage of one or more properties of the combined aerosol-former. For example, triacetin may be combined with glycerin and water to take advantage of the triacetin's ability to transport active components as well as the humectant properties of glycerin.

The aerosol former may also have humectant-type properties which assist in maintaining a desired level of moisture in the aerosol-forming substrate when the substrate is composed of a tobacco-based product comprising, in particular, tobacco particles. In particular, some aerosol-formers are hygroscopic materials that act as humectants, i.e., materials that help keep the tobacco substrate containing the humectant moist.

In particular, the aerosol-forming substrate may comprise one or more aerosol-forming substrates in a proportion by weight in the range 12% to 20%, preferably 16% to 20%, most preferably 17% to 18% by weight of the aerosol-forming substrate.

The aerosol-forming substrate may comprise other additives and ingredients. The aerosol-forming substrate preferably comprises nicotine. The aerosol-forming substrate may comprise flavourants, in particular additional tobacco or non-tobacco volatile flavour compounds, which are released upon heating of the aerosol-forming substrate. The aerosol-forming substrate may also contain capsules containing, for example, additional tobacco or non-tobacco volatile flavour compounds, and such capsules may melt during heating of the solid aerosol-forming substrate. The aerosol-forming substrate may comprise a binder material.

Preferably, the aerosol-forming substrate is an aerosol-forming tobacco substrate, i.e. a tobacco-containing substrate. The aerosol-forming substrate may contain volatile tobacco flavour compounds which are released from the substrate upon heating. The aerosol-forming substrate may comprise or consist of reconstituted tobacco, such as homogenized tobacco material. The homogenised tobacco material may be formed by agglomerating particulate tobacco. In particular, the aerosol-forming substrate may comprise or consist of a cut and mixed tobacco lamina. The aerosol-forming substrate may also comprise non-tobacco materials, for example homogenised plant-based materials other than tobacco. Preferably, the reconstituted tobacco is made as a large extension in the form of a sheet made from blended tobacco material, in particular lamina, processed stems and veins, homogenized plant material, for example using a casting or paper making process. Reconstituted tobacco may also include other post-cut filler tobacco, binders, fibers, or casings. The reconstituted tobacco may comprise at least 25% plant lamina, more preferably at least 50% plant lamina, still more preferably at least 75% plant lamina, and most preferably at least 90% plant lamina. Preferably, the plant material is one of tobacco, mint, tea and clove. However, the plant material may also be another plant material having the ability to release a substance which may subsequently form an aerosol upon application of heat.

Preferably, the tobacco plant material comprises lamina of one or more of flue-cured tobacco lamina, sun-cured tobacco, oriental tobacco and filler tobacco. Flue-cured tobacco is tobacco with generally large, light-colored leaves. Throughout this specification, the term "flue-cured tobacco" is used for tobacco that has been smoked. Examples of flue-cured tobacco are chinese, brazilian, usa, such as virginia, indian, tamsannia or other african flue-cured tobacco. The flue-cured tobacco is characterized by high sugar-nitrogen ratio. From an organoleptic point of view, flue-cured tobacco is a type of tobacco that is accompanied by a pungent and refreshing sensation after curing. As used herein, flue-cured tobacco is tobacco having a reducing sugar content of between about 2.5% and about 20% by dry weight of tobacco leaves and a total ammonia content of less than about 0.12% by dry weight of tobacco leaves. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonia salts. Sun-cured tobacco is tobacco with generally large dark leaves. Throughout this specification, the term "sun-cured tobacco" is used for tobacco that has been air cured. In addition, sun-cured tobacco can be fermented. Tobacco used primarily for chewing, snuff, cigar, and pipe blends is also included in this category. Typically, these sun-cured tobaccos are air-dried and allowed to ferment. From a sensory point of view, sun-cured tobacco is a type of tobacco that is accompanied by a dark cigar-type sensation of smoky flavor after baking. Sun-cured tobacco is characterized by a low sugar nitrogen ratio. Examples of sun-cured tobacco are malavist or other african burley, dark-baked Brazil papao, sun-cured or air-cured Indonesian spider orchid (Indonesian Kasturi). As used herein, sun-cured tobacco is tobacco having a reducing sugar content of less than about 5% by dry weight of tobacco leaves and a total ammonia content of up to about 0.5% by dry weight of tobacco leaves. Aromatic tobacco is tobacco that often has small, light-colored leaves. Throughout the specification, the term "flavourant tobacco" is used for other tobaccos having a high aromatic content, such as essential oils. From an organoleptic point of view, aromatic tobacco is a type of tobacco that is accompanied by a sensation of pungency and aroma after curing. Examples of oriental tobaccos are greek oriental, oriental turkey, semioriental tobaccos, and roasted american burley, such as perlix (pereque), yellow tobacco (Rustica), american burley, or moriland (Meriland). Filler tobacco is not a specific tobacco type, but it comprises tobacco types that are primarily used to supplement other tobacco types used in the blend and do not impart a specific characteristic aroma to the final product. Examples of filler tobacco are stems, midribs or stalks of other tobacco types. A particular example may be the smoked stem of the lower stem of brazil flue-cured tobacco.

Preferably, the aerosol-forming substrate may comprise a tobacco web, preferably a crimped web. The tobacco web can comprise a tobacco material, fibrous particles, a binder material, and an aerosol former. Preferably, the tobacco fibre web is a cast leaf. Cast lamina is a form of reconstituted tobacco formed from a slurry that includes tobacco particles. The cast leaf may also include fibrous particles or an aerosol former, or both fibrous particles and an aerosol former, and a binder and also, for example, a flavorant. Depending on the desired sheet thickness and the casting gap of the corresponding casting box, the tobacco particles may be in the form of tobacco dust having particles of about 10 to 250 microns, preferably about 20 to 80 microns or 50 to 150 microns or 100 to 250 microns. The casting gap affects the thickness of the sheet. The fibre particles may comprise tobacco stem material, stems or other tobacco plant material, and other cellulose based fibres, such as plant fibres, preferably wood fibres or flax fibres. The fiber particles may be selected based on the desire to produce sufficient tensile strength of the cast leaf relative to low impurity rates (e.g., impurity rates between about 2% and 15%). Alternatively, fibers such as vegetable fibers may be used together with the fiber particles. The aerosol former included in the slurry forming the cast leaf may be selected based on one or more characteristics. Functionally, the aerosol-former provides a mechanism that allows the aerosol-former to volatilize and deliver nicotine or flavor or both in the aerosol when heated above a particular volatilization temperature of the aerosol-former. Different aerosol-formers are usually vaporized at different temperatures. The aerosol former may be any suitable known compound or mixture of compounds which in use helps to form a stable aerosol. The stabilised aerosol is substantially resistant to thermal degradation at the operating temperature used to heat the aerosol-forming substrate. The aerosol former may be selected based on its ability to remain stable, e.g. at or near room temperature, but to volatilise at higher temperatures, e.g. between 40 and 450 degrees celsius, preferably between 40 and 250 degrees celsius.

The thickness of the crimped tobacco sheet (e.g., cast leaf) can be in a range between about 0.02 mm and about 0.5 mm, preferably between about 0.08 mm and about 0.2 mm.

In the case of a liquid aerosol-forming substrate, the aerosol-generating article may comprise a liquid retaining material comprising the liquid aerosol-forming substrate. As used herein, the term "liquid retaining material" refers to a high retention or High Release Material (HRM) for storing liquid. The liquid retaining material is configured to inherently retain at least a portion of the liquid, which in turn is unavailable for aerosolization prior to exit retention. Since the liquid aerosol-forming substrate is safely retained in the retaining material, the use of a liquid retaining material reduces the risk of spillage in the event of failure or rupture of the aerosol-generating article. Advantageously, this allows the aerosol-generating article to be leak-proof.

Within the aerosol-generating article, the aerosol-forming substrate may be arranged at least partially around the susceptor. In this configuration, the susceptor is at least partially surrounded by the aerosol-forming substrate in order to heat the substrate from inside. As such, the hottest part of the article, the susceptor, is shielded from the periphery of the article by the substrate. In addition, the susceptor is securely fixed and protected by at least partially surrounding the aerosol-forming substrate.

Alternatively, the susceptor may be arranged at least partially around the aerosol-forming substrate. This arrangement is advantageous for uniformly heating the surrounding aerosol-forming substrate from the outside, wherein the surrounding susceptor forms a heating chamber around the substrate.

In addition to the at least one aerosol-forming substrate and the at least one susceptor, the aerosol-generating article may comprise one or more further substrates. Likewise, the aerosol-generating article may comprise one or more further susceptors.

Furthermore, the aerosol-generating article may comprise different portions each comprising at least one of an aerosol-forming substrate, a flavouring material and a filling material.

As a first example, an aerosol-generating article may comprise:

-at least one cylindrical core portion comprising at least one of a first aerosol-forming substrate and a first flavouring material;

-at least one elongated susceptor comprising an expanded metal sheet comprising a plurality of openings traversing the sheet and laterally abutting the cylindrical core portion in a non-bonded manner extending along its length; and

-a sleeve portion arranged around the wick portion and the susceptor, wherein the sleeve comprises at least one of a filler material, a second aerosol-forming substrate and a second flavouring material.

As a second example, an aerosol-generating article may comprise:

-a first cylindrical core portion comprising a first aerosol-forming substrate and a first flavouring material;

-a second cylindrical wick portion separate from the first wick portion, the second cylindrical wick portion comprising at least one of a second aerosol-forming substrate and a second flavouring material;

-at least one elongated susceptor comprising an expanded metal sheet comprising a plurality of openings through the sheet and laterally abutting the first and second core portions in a non-bonded manner such that the susceptor is sandwiched between the first and second core portions; and

-a sleeve portion arranged around the first and second core portions and the susceptor, wherein the sleeve portion comprises at least one of a filler material, a third aerosol-forming substrate and a third flavouring material.

As a third example, an aerosol-generating article may comprise:

-at least one cylindrical core portion comprising at least one of a first aerosol-forming substrate and a first flavouring material;

-a first elongated susceptor comprising an expanded metal sheet comprising a plurality of openings through the sheet and laterally abutting, preferably in a non-bonded manner, the cylindrical core portion at a first side extending along its length;

-a second elongated susceptor comprising an expanded metal sheet comprising a plurality of openings through the sheet and extending along its length opposite the first side laterally abutting, preferably in a non-bonded manner, the cylindrical core portion at a second side such that the cylindrical core portion is sandwiched between the first and second elongated susceptors; and

-a sleeve portion arranged around the wick portion and the first and second susceptor, wherein the sleeve comprises at least one of a filler material, a second aerosol-forming substrate and a second flavouring material.

The aerosol-generating article, in particular at least one of the parts of the aforementioned first, second and third examples, may comprise at least one of:

-a porous tobacco fibre-based substrate or foam, wherein the tobacco fibres at least partially form a respective aerosol-forming substrate;

-a porous substrate or foam based on plant fibres, wherein the plant fibres at least partially form a corresponding aerosol-forming substrate;

-a filler comprising a cut tobacco material, wherein the cut tobacco material at least partially forms a respective aerosol-forming substrate;

-a filler comprising cut plant material, wherein the cut plant material at least partially forms a corresponding aerosol-forming substrate;

-a liquid retaining material comprising an aerosol-forming liquid, wherein the aerosol-forming liquid at least partially forms a respective aerosol-forming substrate.

Also, the aerosol-generating article, in particular at least one of the parts of the aforementioned first, second and third examples, may comprise at least one of:

-a liquid retaining material comprising at least one flavouring substance, wherein the flavouring substance at least partially forms a respective flavouring material;

-cellulose fibres or cellulose-based fibres (as filler material);

-cellulose fibres or cellulose-based fibres comprising at least one flavouring substance, wherein the flavouring substance at least partially forms a corresponding flavouring material;

-acetate tow bulking fibers (as a filler material);

-plant expanding fibres (as filling material); or

Paper (as filler material).

As used herein, a cut tobacco material can include at least one of tobacco lamina shreds, reconstituted tobacco, tobacco vein fragments, or tobacco stem fragments. Likewise, the cut plant material may comprise pieces of at least one plant lamina, pieces of a plant vein or pieces of a plant stem.

Typically, the aerosol-generating article may be a consumable, in particular a single use consumable. The aerosol-generating article may be a smoking article. In particular, the article may be a rod-like article similar to a cigarette.

Preferably, the inductively heatable aerosol-generating article has a circular cross-section, or an elliptical cross-section, or an oval cross-section. However, the article may also have a square cross-section, or a rectangular cross-section, or a triangular cross-section, or other polygonal cross-section.

The at least one aerosol-forming substrate and the at least one susceptor may be integral parts of an aerosol-forming rod. The aerosol-forming rod may be part of a rod-shaped aerosol-generating article. Likewise, the different parts and susceptor according to the three examples described hereinbefore may be an integral part of an aerosol-forming rod, which in turn may be part of a rod-shaped aerosol-generating article. Preferably, the length dimension of the susceptor substantially corresponds to the length dimension of the aerosol-forming rod as measured along the longitudinal axis of the aerosol-forming rod. However, it may be advantageous to have a susceptor in which the length dimension of the susceptor is less than the length dimension of the aerosol-forming rod.

In addition to the aerosol-forming substrate and susceptor, in particular in addition to the aerosol-forming rod, the article may also comprise one or more different elements, in particular one or more of the following: a support element having a central air passage, an aerosol-cooling element and a filter element. Any one or any combination of these elements may preferably be arranged in sequence to the aerosol-forming rod. Preferably, the aerosol-forming rod is arranged at the distal end of the article. Also, the filter element is preferably arranged at the proximal end of the article. Furthermore, these elements may have the same outer cross-section as the aerosol-forming rod. Preferably, the aerosol-forming rod, the filter element, the support element and the aerosol-cooling element have an outer diameter of between 5 and 10 millimetres, for example between 6 and 8 millimetres. In a preferred embodiment, the filter element has an outer diameter of 7.2mm +/-10%.

The filter element preferably acts as a mouthpiece, or as part of a mouthpiece together with the aerosol-cooling element. As used herein, the term "mouthpiece" refers to the portion of an article through which an aerosol exits an aerosol-generating article. The filter element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The outer diameter of the filter element may be between 5mm and 10mm, for example between 6mm and 8 mm. In a preferred embodiment, the filter element has an outer diameter of 7.2mm +/-10%, preferably 7.2mm +/-5%. The length of the filter element may be between 5mm and 25mm, with a preferred length being between 10mm and 17 mm. In a preferred embodiment, the filter element has a length of 12mm or 14 mm. In another preferred embodiment, the filter element has a length of 7 mm.

The support element may be immediately downstream of the aerosol-forming rod. The support element may abut the aerosol-forming rod. The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of: cellulose acetate, cardboard, crimped paper, such as crimped heat-resistant paper or crimped parchment, and polymeric materials, such as Low Density Polyethylene (LDPE). In a preferred embodiment, the support element is formed from cellulose acetate. The support element may comprise a hollow tubular element. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

Preferably, the outer diameter of the support element is substantially equal to the outer diameter of the aerosol-generating article. The outer diameter of the support element may be between 5mm and 12mm, for example between 5mm and 10mm or between 6mm and 8 mm. In a preferred embodiment, the support element has an outer diameter of 7.2mm +/-10%, preferably 7.2mm +/-5%. The support element may have a length of between 5 and 15mm, in particular between 6 and 12 mm. In a preferred embodiment, the support element has a length of 8 mm.

As used herein, the term "aerosol-cooling element" is used to describe an element having a large surface area and a low resistance to draw (e.g., 15 to 20 mmWG). In use, an aerosol formed from volatile compounds released from the aerosol-forming rod is drawn through the aerosol-cooling element before being delivered to the mouth end of the aerosol-generating article.

Preferably, the aerosol-cooling element has a porosity of more than 50% in the longitudinal direction. Preferably, the airflow path through the aerosol-cooling element is relatively uninhibited. The aerosol-cooling element may be a gathered sheet or a crimped and gathered sheet. The aerosol-cooling element may comprise a sheet material selected from the group consisting of: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), Cellulose Acetate (CA), and aluminum foil or a combination thereof.

In a preferred embodiment, the aerosol-cooling element comprises a gathered sheet of biodegradable material. For example, gathered sheets of non-porous paper or of biodegradable polymeric material, e.g. polylactic acid orGrade (a series of commercially available starch-based copolyesters).

Preferably, the aerosol-cooling element comprises a sheet of PLA, more preferably a rolled gathered sheet of PLA. The aerosol-cooling element may be formed from a sheet having a thickness of between 10 μm and 250 μm, in particular between 40 μm and 80 μm, for example 50 μm. The aerosol-cooling element may be formed from a gathered sheet of material having a width of between 150mm and 250 mm. The specific surface area of the aerosol-cooling element may be between 300 square millimetres per millimetre of length and 1000 square millimetres per millimetre of length, between 10 square millimetres per milligram of weight and 100 square millimetres per milligram of weight. In some embodiments, the aerosol cooling element can be formed from a gathered sheet of material having a specific surface area of about 35 square millimeters per kilogram weight. The outer diameter of the aerosol-cooling element may be between 5mm and 10mm, for example 7 mm.

In some preferred embodiments, the aerosol-cooling element has a length of between 10mm and 15 mm. Preferably, the length of the aerosol-cooling element is between 10mm and 14mm, for example 13 mm. In an alternative embodiment, the length of the aerosol-cooling element is between 15 and 25 millimetres. Preferably, the length of the aerosol-cooling element is between 16mm and 20mm, for example 18 mm.

The article may also include a wrapper that surrounds at least a portion of the various elements described above to hold them together and maintain the desired cross-sectional shape of the article. Preferably, the package forms at least a portion of the outer surface of the article. The wrapper may be, for example, a wrapping paper, in particular a wrapping paper made of cigarette paper. Alternatively, the package may be a foil, for example made of plastic. The wrapper is fluid permeable so as to allow the vapourised aerosol-forming substrate to be released from the article. The fluid permeable wrapper may also allow air to be drawn into the article through its circumference. Further, the wrapper may comprise at least one volatile material which will be activated upon heating and released from the wrapper. For example, the package may be impregnated with a volatile flavouring substance.

The invention further relates to an aerosol-generating system comprising an inductively heatable aerosol-generating article according to the invention and as described herein. The system also includes an inductively heated aerosol-generating device for use with the article. The aerosol-generating device comprises a receiving cavity for at least partially receiving the article in the receiving cavity. The aerosol-generating device further comprises an induction source comprising at least one induction coil for generating an alternating, in particular high frequency, electromagnetic field within the receiving cavity for inductively heating the susceptor of the article when the article is received in the receiving cavity. The at least one induction coil may be a helical induction coil arranged coaxially around the cylindrical receiving cavity.

The apparatus may further comprise a power supply and a controller for supplying power to and controlling the heating process. As mentioned herein, the alternating, in particular high frequency, electromagnetic field may be in the range between 500kHz and 30MHz, in particular between 5MHz and 15MHz, preferably between 5MHz and 10 MHz.

The aerosol-generating device may be, for example, a device as described in WO 2015/177256 a 1.

In use, the aerosol-generating article is engaged with the aerosol-generating device such that the susceptor is located within the fluctuating electromagnetic field generated by the inductor.

Further features and advantages of the aerosol-generating system according to the invention have been described with respect to aerosol-generating articles and are equally applicable.

The present invention also relates to a method for manufacturing an inductively heatable aerosol-generating article according to the present invention and as described herein. The method comprises the following steps:

-providing an aerosol-forming substrate;

-providing a susceptor comprising an expanded metal sheet comprising a plurality of openings, wherein providing the susceptor comprises the steps of:

-providing a metal sheet;

-creating a plurality of weakened areas in the metal sheet; and

-stretching the weakened metal sheet at least in a first direction so as to produce an expanded metal sheet comprising a plurality of openings originating from the plurality of weakened areas;

-arranging a susceptor in thermal proximity or thermal contact with the aerosol-forming substrate.

As used herein, the term "weakened area" refers to an area of the metal sheet that extends in a direction perpendicular to the major surface of the metal sheet, i.e., along the thickness of the metal, with a reduced material thickness. The reduction in material thickness is such that when the weakened metal sheet is stretched, the weakened area transforms into an opening through the entire expanded sheet material along its thickness extension.

In particular, the weakened region is a locally weakened region. Thus, when a plurality of weakened areas are created in the metal sheet, the metal sheet is a weakened, in particular locally weakened, metal sheet.

At the weakened areas, the material thickness may be reduced by at least 50%, in particular by at least 60%, in particular by at least 70%, in particular by at least 80%, in particular by at least 90%, in particular by at least 95%, of the material thickness of the metal sheet at the non-weakened areas. The weakened area may thus be a recess or a cut or a slit, wherein the recess, cut or slit, respectively, extends in a direction perpendicular to the main surface of the metal sheet, i.e. along the thickness of the metal, with a depth of at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%, in particular at least 95% of the material thickness of the metal sheet at the non-weakened area.

The weakened areas may also be perforations extending along their thickness from one planar side of the sheet material through the entire sheet material to the opposite planar side. Accordingly, the step of providing a susceptor comprises the steps of:

-providing a metal sheet;

-producing a plurality of perforations in the metal sheet; and

-stretching the perforated metal sheet at least in a first direction so as to produce an expanded metal sheet comprising a plurality of openings originating from the plurality of perforations.

As already described above with respect to the article, the step of creating a plurality of weakened areas, in particular a plurality of perforations, advantageously comprises the step of forming a plurality of slits of limited length into said metal sheet, wherein at least a portion of each slit extends along a second direction transverse, preferably perpendicular, to the first direction (i.e. transverse, preferably perpendicular, to the expansion direction). The slits may extend in a direction perpendicular to the main surface of the metal sheet, i.e. along the thickness of the metal, with a depth of at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%, in particular at least 95% of the material thickness of the metal sheet at the non-weakened areas. Preferably, the slit extends along its thickness from one planar side of the sheet material through the entire sheet material to the opposite planar side.

One or more of the plurality of weakened areas, in particular one or more of the plurality of perforations, preferably all of the weakened areas, in particular all of the perforations, are straight slits. Straight slits are very easy to manufacture. As mentioned above in relation to the article, straight slits, in particular when extending in a direction perpendicular to the first direction, i.e. the expansion direction, result in diamond shaped openings when the weakened, in particular perforated, metal sheet is stretched in the first direction.

Other shapes of the openings may be achieved by selecting other shapes of the weakened areas, in particular perforations. For example, one or more of the plurality of weakened areas, in particular one or more of the plurality of perforations, preferably all of the weakened areas, in particular all of the perforations, may be curved slits, for example C-shaped slits or U-shaped slits or sickle-shaped slits. Likewise, one or more of the plurality of weakened areas, in particular one or more of the plurality of perforations, preferably all of the weakened areas, in particular all of the perforations, may be a cross-slit or a T-slit. With respect to the cross-shaped slits, one of the slits corresponding to one bar of the cross shape may extend perpendicular to the first direction, and the respective other slits corresponding to the other bar of the cross shape may extend parallel to the first direction. Alternatively, two slits (each of which corresponds to one of the cross-shaped strips) may extend transversely to the first direction and transversely to a direction perpendicular to the first direction.

The plurality of weakened areas, in particular the plurality of perforations, may be arranged in a periodic pattern so as to obtain a plurality of openings arranged in a periodic pattern when stretching the weakened, in particular perforated, metal sheet.

The step of creating a plurality of slits may comprise cutting the plurality of slits.

The step of creating a plurality of slits may be carried out by a slitting machine, in particular a slitting machine that is part of an apparatus, described below, for manufacturing a susceptor for aerosol-generating articles according to the invention. Similar to the apparatus described below, the slitting machine is preferably configured for a continuous through-feed (through-feed) process.

The slitting machine may comprise a first pair of counter-rotating first rollers, wherein at least one of the first rollers comprises one or more cutting elements arranged on an outer circumferential surface of the respective roller, wherein the one or more cutting elements are configured to produce a plurality of weakened areas, in particular a plurality of perforations, for example a plurality of slits, in the metal sheet when passing between said first pair of first rollers.

The step of stretching the weakened, in particular perforated, metal sheet may be achieved by an expansion unit, in particular an expansion unit being part of an apparatus, described below, for manufacturing a susceptor of an aerosol-generating article according to the invention, in particular in a continuous through-feed process. Thus, the expansion unit is preferably configured for a continuous through-feed process. Advantageously, the expansion unit is arranged downstream of the slitting machine described.

The expansion unit may comprise a second pair of counter-rotating second rollers, preferably arranged downstream of the first pair of first rollers, configured to convey the weakened, in particular perforated, metal sheet therebetween at a first conveying speed corresponding to the rotational speed of the second rollers. The expansion unit may further comprise a third pair of counter-rotating third rollers arranged downstream of the second pair, the third rollers being configured to convey a weakened, in particular perforated, metal sheet therebetween at a second conveying speed corresponding to the rotational speed of the third rollers, wherein the rotational speed of the third rollers is higher than the rotational speed of the second rollers, such that the weakened, in particular perforated, metal sheet is stretched in the conveying direction when conveyed by the second and third pairs of rollers, thereby becoming an expanded metal sheet comprising a plurality of openings of the perforated sheet originating from a plurality of weakened areas, in particular from a plurality of perforations.

The step of providing a susceptor may further comprise the step of flattening the expanded metal sheet after stretching.

This step may be achieved by a flattening unit, in particular a flattening unit that is part of an apparatus, described below, for manufacturing a susceptor of an aerosol-generating article according to the invention, in particular in a continuous through-feed process. Thus, the flattening unit is preferably configured for a continuous through-feed process. Advantageously, the flattening unit is arranged downstream of the aforementioned expansion unit.

The flattening unit may comprise a fourth pair of counter-rotating fourth rollers arranged downstream of the third pair of third rollers, the fourth rollers being configured to convey the expanded metal sheet therebetween at a third conveying speed corresponding to a rotational speed of the fourth rollers, wherein the rotational speed of the fourth rollers is higher than the rotational speed of the third rollers, such that the expanded metal sheet is straightened and flattened when conveyed by the third and fourth pairs of rollers.

The step of arranging the susceptor in thermal proximity or thermal contact with the aerosol-forming substrate may comprise arranging the aerosol-forming substrate at least partially around the susceptor.

Alternatively, the step of arranging the susceptor in thermal proximity or thermal contact with the aerosol-forming substrate comprises arranging the aerosol-forming substrate at least partially around the susceptor, or arranging the susceptor at least partially around the aerosol-forming substrate.

Advantageously, the method according to the invention or at least a part of the method according to the invention may be implemented as a continuous process, for example as described in WO 2016/184928 a1 or WO 2016/184929 a 1. In such a continuous process, the aerosol-forming substrate may be provided as a substrate web and the susceptor may be provided as a continuous susceptor profile (profile) as described previously. The latter may comprise a continuous expanded metal sheet comprising a plurality of openings. In particular, the continuous susceptor profile may be produced by a continuous through-feed process as previously described, for example, by using the apparatus described below.

As an example of a continuous process, the method according to the invention may comprise the following steps:

-providing a substrate web comprising an aerosol-forming substrate;

-providing a continuous susceptor profile comprising a continuous expanded metal sheet comprising a plurality of openings, wherein providing the continuous susceptor profile comprises the steps of:

-providing a continuous metal sheet;

-producing a plurality of weakened areas, in particular a plurality of perforations, in the continuous metal sheet; and

-stretching the weakened, in particular perforated, continuous metal sheet at least along a first direction so as to produce a continuous expanded metal sheet comprising a plurality of openings originating from the plurality of weakened areas, in particular from the plurality of perforations;

-gathering the matrix web around a susceptor profile so as to form a continuous rod-like sliver having a cylindrical shape with a constant cross-section;

-cutting the continuous rod-like sliver into individual aerosol-forming rods.

The aerosol-forming rod produced by this method may be used directly as an aerosol-generating article. Alternatively, the aerosol-forming rod may be used to form an aerosol-generating article, in particular a rod-shaped article as described above, which may comprise one or more of a support element having a central air passage, an aerosol-cooling element and a filter element in addition to the aerosol-forming rod.

The use of expanded metal sheet as susceptor in connection with the step of cutting the continuous rod-like sliver into individual aerosol-forming rods is advantageous, because less material will be cut than with a solid metal susceptor. As such, the cutting is less difficult because it requires less mechanical force. As a result, the positional accuracy and stability of the susceptor within the final bar is further improved. Furthermore, the reduced amount of material to be cut advantageously increases the service life of the cutting means used for this process step. Furthermore, the reduced amount of material to be cut reduces the risk of particles migrating into the aerosol-forming substrate. Such particle migration may be due to particle erosion from the susceptor or cutting device during the cutting process.

The method according to the specific example described above may further comprise the step of crimping the matrix web prior to positioning the susceptor profile and the matrix web relative to each other. In particular, the matrix web may be longitudinally crimped. That is, the matrix web may be provided with a longitudinal fold along the longitudinal axis of the continuous sheet (i.e., along the direction of transport of the matrix web). Preferably, the longitudinally folded structure provides the matrix with a zigzag or wavy cross-section. Advantageously, crimping the matrix web facilitates the step of gathering the matrix web in a transverse direction relative to its longitudinal axis into a final rod shape. In particular, the longitudinal folding structure supports a proper folding of the aerosol-forming substrate around the susceptor. This may be advantageous for manufacturing aerosol-forming rods with reproducible dimensions. Even more, the crimped matrix web facilitates precise positioning of susceptor materials having periodically spaced apart narrow portions in the matrix web. As a result, the positional accuracy and stability of the susceptor profile within the aerosol-forming substrate is significantly improved.

The steps of providing a continuous susceptor profile and a substrate web, positioning the susceptor profile and the substrate web relative to each other, gathering the substrate web around the susceptor profile and cutting the continuous rod-like filaments into individual aerosol-forming rods may in principle be realized in different ways, in particular by using one of the methods or apparatuses described in WO 2016/184928 a1 or WO 2016/184929 a 1.

Instead of a continuous process, the method may be implemented at least partly as a discontinuous process. In this case, the expanded metal may have a finite size. In particular, the metal sheets used for manufacturing the expanded metal sheet may have limited dimensions. Accordingly, the method may comprise the steps of:

-providing an aerosol-forming substrate;

-providing a susceptor comprising an expanded metal sheet of limited size comprising a plurality of openings, wherein providing a susceptor comprises the steps of:

-providing a metal sheet of limited dimensions;

-producing a plurality of weakened areas, in particular a plurality of perforations, in the metal sheet; and

-stretching the weakened, in particular perforated, metal sheet at least along a first direction so as to produce an expanded metal sheet of limited size comprising a plurality of openings originating from the plurality of weakened areas, in particular from the plurality of perforations;

-arranging a susceptor in thermal proximity or thermal contact with the aerosol-forming substrate.

Alternatively, the metal sheet used for manufacturing the limited expanded metal sheet may be a continuous metal sheet which, after the drawing step, may be cut into a plurality of expanded metal sheets of limited size. Accordingly, the method may comprise the steps of:

-providing an aerosol-forming substrate;

-providing a susceptor comprising an expanded metal sheet of limited size comprising a plurality of openings, wherein providing a susceptor comprises the steps of:

-providing a continuous metal sheet;

-producing a plurality of weakened areas, in particular a plurality of perforations, in the continuous metal sheet; and

-stretching the weakened, in particular perforated, continuous metal sheet at least along a first direction so as to produce a continuous expanded metal sheet comprising a plurality of openings originating from the plurality of weakened areas, in particular from the plurality of perforations;

-cutting the continuous expanded metal sheet into a plurality of expanded metal sheets of limited size, one of the expanded metal sheets being used to provide the susceptor;

-arranging a susceptor in thermal proximity or thermal contact with the aerosol-forming substrate.

Further features and advantages of the method for manufacturing an inductively heatable aerosol-generating article have been described in relation to aerosol-generating articles according to the present invention and are equally applicable.

The invention also relates to an apparatus for manufacturing a susceptor for manufacturing aerosol-generating articles according to the invention, in particular in a continuous process. The apparatus comprises:

-a first pair of counter-rotating first rollers, wherein at least one of the first rollers comprises one or more cutting elements arranged on the outer circumferential surface of the respective roller, wherein the one or more cutting elements are configured to create a plurality of weakened areas, in particular a plurality of perforations, for example a plurality of slits, in the metal sheet when passing between said first pair of first rollers;

-a second pair of counter-rotating second rollers arranged downstream of the first pair of first rollers, the second rollers being configured to convey the weakened, in particular perforated, metal sheet therebetween at a first conveying speed corresponding to the rotational speed of the second rollers; and

-a third pair of counter-rotating third rollers arranged downstream of the second pair of second rollers, the third rollers being configured to convey the weakened, in particular perforated, metal sheet therebetween at a second conveying speed corresponding to the rotational speed of the third rollers, wherein the rotational speed of the third rollers is higher than the rotational speed of the second rollers, such that the weakened, in particular perforated, metal sheet is stretched in the conveying direction when conveyed by the second and third pairs of rollers, thereby becoming an expanded metal sheet comprising a plurality of openings through the sheet originating from the plurality of weakened areas, in particular from the plurality of perforations.

Preferably, the rotational speed of the first roller is equal to the rotational speed of the second roller, such that no expansion occurs between the first pair of first rollers and the second pair of second rollers.

Further, the apparatus may comprise a fourth pair of counter-rotating fourth rollers arranged downstream of the third pair of third rollers, the fourth rollers being configured to convey the expanded metal sheet therebetween at a third conveying speed corresponding to a rotational speed of the fourth rollers, wherein the rotational speed of the fourth rollers is higher than the rotational speed of the third rollers, such that the expanded metal sheet is straightened and flattened when conveyed by the third and fourth pairs of rollers.

As described above in relation to the method according to the invention, the first pair of first rollers may be part of a slitting machine or may form a slitting machine. Likewise, the second and third pairs of rolls may be part of or may form an expansion unit, while the fourth pair of rolls, possibly in combination with the third pair of rolls, may be part of or may form a flattening unit.

The apparatus may further comprise an adjustment mechanism for at least one, and preferably each, of the first, second, third and fourth pairs of rollers. The respective adjustment mechanism may be configured to adjust at least one of a distance and an orientation between the rollers or the rollers of the respective pair, in particular an inclination of a rotational axis of each roller of the respective pair of rollers. The respective adjustment mechanism may be part of the respective unit described above.

Preferably, the apparatus may be used for performing at least part of the method according to the invention and as described herein, in particular if the method is implemented as a continuous process or at least part of a discontinuous process.

Further features and advantages of the device have been described in relation to the aerosol-generating article and method according to the invention, and are equally applicable.

Drawings

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

figure 1 is a schematic illustration of an inductively heatable aerosol-generating article according to an exemplary embodiment of the present invention;

figure 2 is a schematic diagram of an exemplary embodiment of an aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article according to figure 1;

figure 3 shows a further exemplary embodiment of a susceptor that may be used to form an aerosol-generating article according to figure 1; and

figure 4 schematically shows an exemplary embodiment of an apparatus for manufacturing a susceptor that can be used to form an aerosol-generating article according to the present invention.

Detailed Description

Figure 1 schematically shows an exemplary embodiment of an inductively heatable aerosol-generating article 1 according to the present invention. The aerosol-generating article 1 has substantially the shape of a rod and comprises four elements arranged in sequence in coaxial alignment: an aerosol-forming stem 10 comprising a susceptor 20 and an aerosol-forming substrate 30, a support element 40, an aerosol-cooling element 50, and a filter element 60. The aerosol-forming rod 10 is arranged at the distal end 2 of the article 1, while the filter element 60 is arranged at the proximal end 3 of the article 1. The support element 40 may comprise a cartoon or cellulose based tube with a central air channel 41 that allows mixing and homogenization of any aerosol generated inside the aerosol-forming rod 10. Alternatively, the support element 40 may be used to keep separate different aerosols generated at different locations inside the aerosol-forming rod separate until reaching the aerosol-cooling element 50. The aerosol-cooling element 50 is primarily used to reduce the aerosol temperature towards the proximal end 3 of the article 1. The aerosol-forming element may for example comprise a biodegradable polymeric material, a cellulose-based material with low porosity or a combination of these and other materials. The filter element 60 may, together with at least a portion of the aerosol-cooling element 50, act as a mouthpiece through which the aerosol exits the aerosol-generating article 1. The filter element 60 may comprise standard filter material, such as low density acetate tow. Each of the four elements 10, 40, 50, 60 is substantially cylindrical, all of which have substantially the same diameter or circumference. Further, the four elements are surrounded by an outer wrapper 70 in order to hold the four elements together and maintain the desired circular cross-sectional shape of the rod-shaped article 1. The wrapper 70 is preferably made of paper.

The rod-shaped aerosol-generating article 1 may have a length of between 30 mm and 110 mm, preferably between 40 mm and 60 mm. Also, the diameter of the article 1 may be between 3 and 10mm, preferably between 5.5 and 8 mm. In addition to the details of the susceptor 20 within the rod 10, further details of the article, in particular further details of the four elements, are disclosed in WO 2015/176898 a 1.

As shown in fig. 2, the aerosol-generating article 1 is configured for use with an inductively heated aerosol-generating device 80. The device 80 and the article 1 together form an aerosol-generating system 90. The aerosol-generating device 80 comprises a cylindrical receiving cavity 82 defined within a distal portion of the device housing 81 for receiving at least a distal portion of the article 1 therein. The device 80 further comprises an induction source comprising an induction coil 83 for generating an alternating, in particular high frequency, electromagnetic field. In the present embodiment, the induction coil 83 is a helical coil circumferentially surrounding the cylindrical receiving cavity 82, such that the susceptor 20 of the article 1 can experience the electromagnetic field of the coil when the article 1 is received in the cavity 82. Thus, upon activation of the induction source, the susceptor element 20 heats up until a temperature is reached which is sufficient to release material from the aerosol-forming substrate 30 surrounding the susceptor 20.

As can also be seen in fig. 2, the device 80 further comprises a power source 85 and a controller 84 (only schematically shown in fig. 2) for powering and controlling the heating process. Preferably, the induction source is at least partially an integral part of the controller 84.

According to the invention, the susceptor 20 is in thermal contact with the aerosol-forming substrate 30. In the embodiment of the article 1 shown in fig. 1 and 2, the aerosol-forming substrate 30 surrounds the susceptor 20 so as to define the generally cylindrical shape of the rod 10. The elongated susceptor 20 is substantially strip-like and arranged along the central axis of the article 1.

The strip-like susceptor 20 has a rectangular cross-sectional profile, as seen in a plane perpendicular to the central axis of the article 1, wherein the thickness extension of the susceptor 20 is smaller than the width extension 27, which in turn is smaller than the length extension 28 along the central axis. As can be seen in fig. 1 and 2, the length 28 is substantially the same as the length of the aerosol-forming substrate 30, i.e. the length of the rod 10.

According to the invention, the susceptor comprises an expanded metal sheet 21 comprising a plurality of openings 22, 23 extending through the sheet 21 along its thickness. As will be described in more detail below, the openings 22, 23 in the expanded metal sheet 21 are caused by: locally weakened, in particular perforated, and subsequently stretched, the metal sheet such that a regular pattern of openings originating from the expansion of the locally weakened areas of the metal sheet, in particular from the perforations in the metal sheet, is formed.

As described above, the use of expanded metal sheet as susceptor 20 advantageously allows saving material and production costs, and therefore resources. In addition, due to the plurality of openings 22, 23, the susceptor 20 is permeable such that the air flow drawn through the article 1 is enhanced compared to an article comprising an impermeable susceptor. In addition, the openings 22, 23 facilitate the release and entrainment of material volatilised from the heated aerosol-forming substrate 30 into the airflow through the article 1.

In the present embodiment, the expanded metal sheet 21 of the susceptor 20 comprises two types of openings, namely an opening 22 with a closed boundary, i.e. which is completely delimited by the material of the expanded metal sheet 21, and an opening 23 with a partially open boundary, i.e. which is only partially delimited by the material of the expanded metal sheet 21. The latter are located at both side edges of the strip-like susceptor 20. That is, the openings 23 open laterally toward the respective side edges.

As shown in fig. 1 and 2, the opening 22 has a substantially diamond shape, and the opening 23 has a substantially triangular shape. In the present embodiment, both types of openings 22, 23 are produced as a result of the expansion of the perforations that have been produced in the metal sheet prior to expansion. The perforations are essentially straight slits of limited length that have been cut into the metal sheet prior to expansion. The slit which, when expanded, creates a partially unbounded opening 23 has been cut so as to extend beyond the side edges of the metal sheet. In contrast, the slit that creates the bounded opening 22 has been cut so as to be entirely within the boundaries of the metal sheet. In the present embodiment, both types of slits are oriented perpendicular to the direction along which the metal sheet has been expanded, which is the length extension of the expanded metal sheet 21.

As can also be seen in fig. 1 and 2, the expanded metal sheet 21 comprises a single row of diamond-shaped openings 22 along the centre line (i.e. extending parallel to its length) of the strip-like susceptor 20. Between each adjacent diamond shaped opening 22, two partially bounded openings 23 are arranged in an offset configuration at opposite side edges of the strip-like susceptor 20. Due to this periodic pattern of deflection of the openings 22, 23, the susceptor 20 advantageously has an increased density of openings per unit area, which results in a high permeability per unit area and a low overall mass. The diamond shaped openings 22 have a first diagonal connecting a first pair of opposing vertices of the diamond shape and a second diagonal connecting a second pair of opposing vertices of the diamond shape. As described above, the first diagonal line extends in a first direction, which corresponds to the expansion direction of the expanded metal sheet, which in turn extends perpendicular to the length of the straight slits that produce the diamond-shaped openings 22 when expanded. The length of the first diagonal may be in the range of 0.3 mm to 3.1 mm, preferably in the range of 0.5 mm to 2.5 mm. Likewise, the length of the second diagonal is in the range of 1.7 mm to 4.7 mm, preferably in the range of 1.1 mm to 3.1 mm. The shortest distance between the rhombus-shaped opening of the susceptor 20 and the nearest side edge of the strip-shaped metal sheet 21 may be in the range of 1.7 mm to 4.3 mm, preferably in the range of 1.5 mm to 2.0 mm. The length of the opening edge of the triangular opening 23 along the side edge of the susceptor 20 may be in the range of 0.2 mm to 2.7 mm, preferably in the range of 0.3 mm to 1.1 mm.

Depending on the width of the strip-like susceptor and the size of the openings, the susceptor may comprise more than one row of fully bounded openings. This configuration is shown in fig. 3, which shows an alternative embodiment of a strip-like susceptor 120. The strip-shaped susceptor 120 according to this embodiment comprises two rows of diamond-shaped openings 122 symmetrically arranged along a center line of the susceptor 120 extending parallel to its length. Between each adjacent diamond-shaped opening 122, the susceptor 120 includes a central diamond-shaped opening 124 and two partially bounded openings 123 at opposite side edges of the susceptor 120. The central diamond-shaped opening 124 and the two partially bounded openings 123 are arranged in an offset configuration relative to the diamond-shaped openings 122 in respective adjacent rows.

With regard to both embodiments of the susceptor 20, 120, the respective expanded metal sheet 21, 121 is preferably a double-layer sheet comprising a first layer made of ferromagnetic stainless steel, the first layer comprising on at least one side a nickel coating forming a second layer of the double-layer sheet. Due to the magnetic and electrical properties of ferromagnetic stainless steel, the first layer is inductively heated due to both eddy currents and hysteresis losses. Thus, the first layer is optimized with respect to heat loss and thus provides the main heating. In contrast, the second layer serves primarily as a temperature marker. This is based on the magnetic properties of nickel, which has a curie temperature that is about the same as the temperature to which the susceptor 20 should be heated in order to generate an aerosol from the substrate 30, but is still low enough to avoid local overheating or burning of the substrate 30.

Fig. 4 schematically shows an exemplary embodiment of an apparatus 200 for manufacturing a susceptor 120, which may be used to form an aerosol-generating article according to the present invention.

Preferably, the device 200 may be used for performing at least part of a method according to the invention for manufacturing an inductively heatable aerosol-generating article, in particular performing the step of providing a susceptor comprising an expanded metal sheet comprising a plurality of openings.

The upper part of fig. 4 shows the device 200 itself, while the lower part of fig. 4 shows the functions and results of the different units of the device 200 and of the different sub-steps of providing the susceptor 120.

The step of providing the susceptor 120 according to the present invention begins with providing a metal sheet 190. Preferably, the metal sheet 190 is provided as a continuous metal sheet, for example as a metal strip provided on a coil former. To this end, the apparatus may comprise an unwinding unit to unwind the continuous metal sheet from the coil former (not shown).

Next, the step of providing the susceptor 120 comprises the step of creating a plurality of weakened areas in the sheet of metal. In an embodiment, the weakened area is a perforation in the metal sheet. To this end, the apparatus 200 comprises a splitting machine 201. The slitting machine 201 comprises a first pair 210 of counter-rotating first rollers 211, 212 between which the metal sheet 190 is fed at the upstream end of the apparatus 200. At least one of the first rollers 211, 212 comprises one or more cutting elements arranged on the outer circumferential surface of the respective roller 211, 212 (not shown). The one or more cutting elements are configured to create a plurality of perforations in the metal sheet 190 as the metal sheet 190 passes between the first rollers 211, 212. Thus, the process produces a perforated metal sheet 180 at the downstream end of the slitter 201. In the current embodiment of the apparatus 200, the cutting elements of the slitting machine 201 are configured to produce a periodic pattern of straight slits 182, 183 that extend perpendicular to the direction of travel of the sheet metal through the apparatus 200. As shown in the lower portion of fig. 4 (the second sub-figure from the right), the resulting perforated metal sheet 180 includes a slit 182 completely within the boundaries of the metal sheet, and a slit 183 extending beyond the side edges of the metal sheet.

Next, the step of providing the susceptor 120 comprises the step of stretching the weakened, in particular perforated, metal sheet 180 at least in a first direction so as to produce an expanded metal sheet 190 comprising a plurality of openings originating from the plurality of perforations 182, 183. To this end, the apparatus 200 comprises an expansion unit 202.

The expansion unit 202 comprises a second pair 220 of counter-rotating second rollers 221, 222 arranged downstream of the first pair 210 of first rollers 211, 212. The second rollers 221, 222 are configured to convey the weakened, in particular perforated, metal sheet 180 therebetween at a first conveying speed V1 corresponding to the rotational speed of the second rollers 221, 222. Preferably, the rotational speed of the first rollers 211, 212 is equal to the rotational speed of the second rollers 221, 222, such that no stretching occurs between the first pair 210 of first rollers 211, 212 and the second pair 220 of second rollers 221, 222.

Downstream of the second pair 220 of second rollers 221, 222, the expansion unit 202 comprises a third pair 230 of counter-rotating third rollers 231, 232 configured to convey the weakened, in particular perforated, metal sheet 180 therebetween at a second conveying speed V2 corresponding to the rotation speed of the third rollers 231, 232. The third rollers 231, 232 have a higher rotational speed than the second rollers 221, 222, so that the weakened, in particular perforated, metal sheet 180 is stretched in the conveying direction when conveyed by the second pair of rollers 220 and the third pair of rollers 230. Thereby, the weakened, in particular perforated, metal sheet 180 becomes an expanded metal sheet 170 comprising a plurality of openings 172, 173 originating from a plurality of perforations 182, 183.

Downstream of the third pair 230 of third rollers 231, 232, the apparatus 200 comprises a flattening unit 203. The flattening unit 203 comprises a fourth pair 240 of counter-rotating fourth rollers 241, 242 configured to convey the expanded metal sheet 170 therebetween at a third conveying speed V3 corresponding to the rotation speed of the fourth rollers 241, 242. The rotational speed of the fourth rollers 241, 242 is selected to be higher than the rotational speed of the third rollers 231, 232 so that the expanded metal sheet 170 is straightened and flattened as it is conveyed by the third and fourth pairs of rollers 230, 240.

At the downstream end of the device 200, the above-described steps ultimately produce a (continuously) flattened expanded metal sheet 200 that can be used to form the susceptor 120 as shown in fig. 3.

As also shown in fig. 4, the apparatus 200 may further include an adjustment mechanism 215, 225, 235, 245 for each of the first, second, third, and fourth pairs of rollers 210, 220, 230, 240. The respective adjustment mechanism 215, 225, 235, 245 is configured to adjust the distance and orientation between the rollers of the respective pair 210, 220, 230, 240, in particular the inclination of the rotational axis of each roller of the respective pair 210, 220, 230, 240.

As described above, the device 200 is preferably used for performing the steps of providing the sensor of the method according to the invention, in particular if the method is implemented as a continuous process. According to this aspect, the method may further comprise the step of providing a substrate web comprising an aerosol-forming substrate in parallel, before or after providing the susceptor. Subsequently, the method may comprise the step of gathering the substrate web around a susceptor profile so as to form a continuous rod-like sliver having a cylindrical shape with a constant cross-section, and then the step of cutting the continuous rod-like sliver into individual aerosol-forming rods. The aerosol-forming rod produced by this method may be used directly as an aerosol-generating article. Alternatively, the aerosol-forming rod 10 may be used to form an aerosol-generating article 1 as shown in figure 1.