JP7515470B2 - Smoking substitute consumables - Google Patents

Description

The present disclosure relates to consumables for use in smoking substitution systems, and more particularly, but not exclusively, to heat-not-burn (HNB) consumables.

Tobacco smoking is generally regarded as exposing smokers to potentially harmful substances. It is generally believed that significant amounts of potentially harmful substances are produced through the burning of tobacco and/or the heat caused by tobacco combustion, as well as through the burnt tobacco components in the tobacco smoke itself.

A conventional combustible smoking article, such as a cigarette, typically includes a cylindrical tobacco rod comprising strips of tobacco surrounded by a wrapper, and typically also includes a cylindrical filter axially aligned in abutting relationship with the rolled tobacco rod. The filter typically includes a filtration material circumscribed by a plug wrap. The rolled tobacco rod and filter are held together by a rolled strip of tipping paper that circumscribes the entire length of the filter and adjacent portions of the rolled tobacco rod. This type of conventional cigarette is used by lighting the end opposite the filter to burn the tobacco rod. The smoker receives mainstream smoke from his or her mouth by drawing on the mouth or filter end of the cigarette.

The combustion of organic materials such as tobacco is known to produce tar and other potentially harmful by-products. To avoid smoking tobacco, various smoking substitution systems (or "substitute smoking systems") have been proposed.

Such smoking substitution systems can form part of nicotine replacement therapy aimed at people wishing to quit smoking and overcome their dependence on nicotine.

Smoking substitution systems include electronic systems that allow a user to simulate the act of smoking by producing an aerosol (also called "vapor") that is drawn (inhaled) through the mouth into the lungs and then exhaled. The inhaled aerosol typically contains nicotine and/or flavorings without or with fewer odors and health risks associated with traditional smoking.

Generally, smoking substitution systems are intended to provide a substitute for the habitual behavior of smoking while providing users with an experience and satisfaction similar to that experienced with traditional smoking and combustible tobacco products. Some smoking substitution systems use smoking substitution articles, which are designed to resemble a traditional cigarette and are cylindrical in shape with a mouthpiece at one end.

The popularity and use of smoking-substitution systems has grown rapidly over the past few years. Although originally marketed as an aid to assist habitual smokers wishing to quit smoking tobacco, consumers increasingly view smoking-substitution systems as a desirable lifestyle accessory.

There are several different categories of smoking substitution systems, each of which utilizes a different smoking substitution approach.

One approach for smoking substitution systems is the so-called "heat-not-burn" ("HNB") approach, in which tobacco (not "e-liquid") is heated or warmed to release vapor. The tobacco may be leaf tobacco or reconstituted tobacco. The vapor may contain nicotine and/or flavorings. In the HNB approach, the intention is that the tobacco is heated without being burned, i.e., the tobacco does not undergo combustion.

A typical HNB smoking substitution system may include a device and a consumable. The consumable may include tobacco material. The device and consumable may be configured to be physically coupled together. In use, heat may be applied to the tobacco material by a heating element of the device, and airflow through the tobacco material causes moisture in the tobacco material to be released as vapor. The vapor may also be formed from the carrier (which may include, for example, propylene glycol and/or vegetable glycerin)/humectant in the tobacco material, as well as volatile compounds released from the tobacco. The released vapor may be entrained in the airflow drawn through the tobacco.

As the vapor passes through the consumable (entrained in the airflow) from the inlet to the mouthpiece (outlet), it cools and condenses to form an aerosol for inhalation by the user. The aerosol typically contains volatile compounds.

Known HNB consumables often result in insufficient mixing of the vapor components, i.e., incomplete mixing of nicotine and PG/VG, due to evaporation from tobacco at different temperatures. Unmixed nicotine gas can result in an unpleasant sensation for the user.

In the HNB smoking substitution system, it is believed that heating, as opposed to burning, tobacco material results in fewer or lower amounts of more harmful compounds typically produced during smoking. As a result, the HNB approach can reduce odor and/or health risks that can result through tobacco burning, tobacco combustion, and pyrolytic degradation.

Improved designs of HNB consumables are needed to enhance the user experience and improve the functionality of HNB smoking substitution systems, for example to improve the mixing of vapour components.

This disclosure was devised in light of the above problems.

Most generally, the present disclosure relates to an aerosol-forming article, such as a smoking substitute article, such as an HNB consumable, having a flow restrictor element located downstream of an aerosol-forming substrate.

According to a first aspect, there is provided a heat-not-burn (HNB) consumable comprising an aerosol-forming substrate and a flow restrictor element located downstream of the aerosol-forming substrate.

In a second aspect, an aerosol-forming article (e.g., a smoking substitute article such as an HNB consumable) is provided that includes an aerosol-forming substrate, an upstream filter element, a spacer element, and a terminal filter element in an axial flow arrangement, at least one of the filter elements being a hollow filter element, and the article further includes a flow restrictor element located upstream of the terminal filter element and downstream of the aerosol-forming substrate.

By providing a flow restrictor element downstream of the aerosol-forming substrate, the various components of the vapour share the same location, thus mixing these components as they pass through the flow restrictor element. This means that the user is not exposed to unmixed nicotine vapour.

Optional features are described below. These may be applied alone or in any combination with any aspect.

The flow restrictor element may include a disk or rod having at least one axial perforation or channel. For example, the flow restrictor element may include a disk or rod having a single perforation or channel, for example in its axial center. The or each perforation/channel may have a diameter of 0.5-1.5 mm, for example about 1 mm.

During manufacture of the consumable/article, the size of the perforations/channels can be selected depending on the desired delivery of a nicotine "hit."

The flow restrictor element may be formed from a vapor impermeable material, for example a metal foil (e.g., aluminum foil) or a plastic material. In other embodiments, the flow restrictor element may be formed from extruded tobacco or activated carbon.

The HNB consumable of the first aspect preferably includes, in an axial flow arrangement, an aerosol-forming substrate, an upstream filter element, a spacer element, and a terminal filter element, at least one of the filter elements being a hollow filter element, and a flow restrictor element being provided upstream of the terminal filter element and downstream of the aerosol-forming substrate.

In both the first and second aspects, a flow restrictor element may be provided upstream of the spacer element. This allows expansion of the restricted vapor flow into a mixing chamber defined by the spacer element, further improving mixing of the vapor components. In some embodiments, the restrictor element is provided immediately upstream of the spacer element, i.e., interposed between the upstream filter element and the spacer element.

The aerosol-forming article of the second aspect is preferably a heat-not-burn (HNB) consumable product.

The aerosol-forming substrate is capable of being heated to release at least one volatile compound capable of forming an aerosol. The aerosol-forming substrate may be located at the upstream end of the article/consumable.

As used herein, the terms "upstream" and "downstream" are intended to refer to the flow direction of the vapor/aerosol, i.e., the downstream end of the article/consumable is the mouth end or outlet where the aerosol exits the article/consumable for inhalation by the user. The upstream end of the article/consumable is the end opposite the downstream end. The term "axial flow direction" refers to the direction from the upstream end to the downstream end of the article/consumable.

To generate an aerosol, the aerosol-forming substrate comprises at least one volatile compound that is intended to be vaporized/aerosolized and that, when inhaled, can provide a recreational and/or medicinal effect to the user. Suitable chemically and/or physiologically active volatile compounds include the group consisting of nicotine, cocaine, caffeine, opiates and opioids, cathine and cathinones, kavalactones, mysticin, beta-carboline alkaloids, salvinorin A, together with any combinations, functional equivalents, and/or synthetic substitutes of the above.

The aerosol-forming substrate may include plant material. Amaranthus dubius, Arctostaphylos uvā-ursi (Bearberry), Argemone mexicana, Amica, Artemisia vulgaris, Yellow Tees, Galea zacatechichi, Canavalia maritima (Baybean), Cecropia mexicana (Guamura), Cestrum noctum, Cynoglossum virginianum (wild comfrey), Cytisus scoparius, Damiana, Entada rheedii, Eschscholzia califomica (California Poppy), Fittonia albivenis, Hippobroma longiflora, Humulus japonica (Japanese Hops), Humulus lupulus (Hops), Lactuca virosa (Lettuce Opium), Laggera alata, Leonotis leonurus, Leonurus cardiaca (Motherwort), Leonurus sibiricus (Honeyweed), Lobelia cardinalis, Lobelia inflata (Indian-tobacco), Lobelia siphilitica, Nepeta cataria (Catnip), Nicotiana species (Tobacco), Nymphaea alba (White Lily), Nymphaea caerulea (Blue Lily), Opium poppy, Passiflora incamata (Passionflower), Pedicularis densiflora (Indian Warrior), Pedicularis groenlandica (Elephant's Head), Salvia divinorum, Salvia dorrii (Tobacco Sage), Salvia species (Sage), Scutellaria galericulata, Scutellaria lateriflora, Scutellaria nana, Scutellaria species (Skullcap), Sida acuta (Wireweed), Sida rhombifolia, Silene capensis, Syzygium At least one plant material selected from the list including: Aralia aromaticum (Clave), Tagetes lucida (Mexican Tarragon), Tarchonanthus camphoratus, Tumera diffusa (Damiana), Verbascum (Mullein), Zamia latifolia (Maconha Brava), together with any combination, functional equivalent, and/or synthetic alternative of the above.

Preferably, the plant material is tobacco. Any type of tobacco may be used, including, but not limited to, flue-cured, burley, Maryland, dark air-cured, oriental, dark fire-cured, perique, and rustica. This also includes blends of the tobaccos mentioned above.

Any suitable part of the tobacco plant may be used, including the leaves, stems, roots, bark, seeds, and flowers.

The tobacco may include one or more of leaf tobacco, stem tobacco, tobacco powder, tobacco dust, tobacco derivatives, expanded tobacco, homogenized tobacco, cut tobacco, extruded tobacco, cut rag tobacco, and/or reconstituted tobacco (e.g., slurry recon or paper recon).

The aerosol-forming substrate may include a homogenous (e.g. paper/slurry recon) tobacco collecting sheet, or collecting strips/strips formed from such a sheet.

In some embodiments, the sheet used to form the aerosol-forming substrate has a basis weight of 100 g/m ² or more, for example 110 g/m ² or more, such as 120 g/m ² or more.

The sheet may have a basis weight of 300 g/ ^m2 or less, such as 250 g/ ^m2 or less, or 200 g/ ^m2 or less.

The sheets may have a basis weight of 120 to 190 g/m ² .

The aerosol-forming substrate may comprise at least 50% by weight of plant material, such as at least 60% by weight of plant material, for example about 65% by weight of plant material. The aerosol-forming substrate may comprise up to 80% by weight of plant material, for example up to 75 or 70% by weight of plant material.

The aerosol-forming substrate may include one or more additives selected from humectants, flavorings, fillers, aqueous/non-aqueous solvents, and binders.

Humectants are provided as a source of vapor generation and the resulting vapor helps retain volatile active compounds and increases the visible vapor. Suitable humectants include polyhydric alcohols (e.g., propylene glycol (PG), triethylene glycol, 1,2-butanediol, and vegetable glycerin (VG)) and their esters (e.g., glycerol monoacetate, diacetate, or triacetate). The humectant may be present in an amount of 1-50% by weight in the aerosol-forming substrate.

The humectant content of the aerosol-forming substrate can have a lower limit of at least 1% by weight of the plant material, such as at least 2% by weight, such as at least 5% by weight, such as at least 10% by weight, such as at least 20% by weight, such as at least 30% by weight, or such as at least 40% by weight.

The humectant content of the aerosol-forming substrate may have an upper limit of at most 50% by weight of the plant material, such as at most 40% by weight, such as at most 30% by weight, or such as at most 20% by weight.

Preferably, the humectant content is 1-40% by weight of the aerosol-forming substrate, such as 1-20% by weight.

Suitable binders are known in the art and can act to bind together the components that form the aerosol-forming substrate. Binders can include starch and/or cellulose binders such as methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, and methylcellulose; gums such as xanthan gum, guar gum, gum arabic, and/or locust bean gum; organic acids and their salts such as alginic acid/sodium alginate, agar, and pectin.

Preferably, the binder content is 5-10% by weight of the aerosol-forming substrate, for example about 6-8% by weight.

Suitable fillers are known in the art and can act to enhance the aerosol-forming substrate. Fillers can include fibrous (non-tobacco) fillers such as cellulose fibers, lignocellulosic fibers (e.g., wood fibers), jute fibers, and combinations thereof.

Preferably, the filler content is 5-10% by weight of the aerosol-forming substrate, for example about 6-9% by weight.

The aerosol-forming substrate may comprise an aqueous and/or non-aqueous solvent. In some embodiments, the aerosol-forming substrate has a moisture content of 5-10% by weight, for example 6-9% by weight, such as 7-9% by weight.

The flavorings may be provided in solid or liquid form. The flavorings may include menthol, licorice, chocolate, fruit flavors (including, for example, citrus, cherry, etc.), vanilla, spices (e.g., ginger, cinnamon), and tobacco flavors. The flavorings may be uniformly dispersed throughout the aerosol-forming substrate or may be provided at discrete locations and/or varying concentrations throughout the aerosol-forming substrate.

The aerosol-forming substrate may be formed in a substantially cylindrical shape such that the article/consumable resembles a conventional cigarette. The aerosol-forming substrate may have a diameter of 5-10 mm, for example 6-9 mm or 6-8 mm, for example about 7 mm. The aerosol-forming substrate may have an axial length of 10-15 mm, for example 11-14 mm, such as about 12 or 13 mm.

The aerosol-forming substrate may be circumscribed by a wrap layer, for example a paper wrap layer. The wrap layer may overlie an inner foil layer or may comprise a paper/foil laminate (foil innermost).

The HNB consumable of the first aspect can include an upstream filter element and a terminal filter element, and the article of the second aspect includes an upstream filter element and a terminal filter element. The upstream filter element is located upstream of the terminal filter element (but downstream of the aerosol-forming substrate). The terminal filter element may be located at the downstream/mouth end of the article/consumable.

One or both of the filter elements may be constructed from cellulose acetate or polypropylene tow. One or both of the filter elements may be constructed from activated carbon. One or both of the filter elements may be constructed from paper. One or both of the filter elements may be circumscribed by a respective plug wrap, e.g., a paper plug wrap.

The filter elements may each have a substantially cylindrical shape, the diameter of which substantially corresponds to the diameter of the aerosol-forming substrate (with or without its associated wrap layer). The axial length of the or each filter element may be less than 20 mm, e.g., 8-15 mm, e.g., 9-13 mm, e.g., 10-12 mm.

At least one of the filter elements is a hollow filter element. In some embodiments, both filter elements are hollow filter elements. The or each hollow filter may have a diameter of 1 to 5 mm, for example 2 to 4 mm, or 2 to 3 mm. If the upstream filter element is a hollow filter element, the diameter is preferably larger than the diameter of the perforations in the flow restrictor, i.e. preferably larger than 1.5 mm.

The upstream filter element may be at least partially (e.g. entirely) circumscribed by a (paper) wrap layer.

The terminal filter element (the downstream end of the article/consumable) can be joined to the upstream element by a circumscribing tipping layer, e.g., a tipping paper layer, to form the article/consumable. The tipping paper can have an axial length that is greater than the axial length of the terminal filter element, such that the tipping paper completely circumscribing the terminal filter element and the wrap layer surrounding the adjacent upstream element, e.g., the adjacent upstream spacer element.

In an embodiment where only one of the filter elements is a hollow filter element, the other (solid) filter element may contain a capsule, e.g. a crushable capsule (crush ball), containing a liquid flavourant, e.g. any of the flavourants listed above. The capsule can be crushed by the user to release the flavourant during smoking of the article/consumable. The capsule may be located in the axial centre of the (solid) filter element.

The spacer element defines a space or cavity or chamber between the aerosol-forming substrate and the downstream end of the article/consumable. The spacer acts to allow both cooling and mixing of the aerosol. The spacer element may comprise a paper tube. The spacer element may be at least partially (e.g. entirely) circumscribed by a (paper) wrap layer.

The spacer element may have an outer diameter of 5-10 mm, e.g., 6-9 mm or 6-8 mm, e.g., about 7 mm. The spacer element may have an axial length of 10-15 mm, e.g., 12-14 mm or 13-14 mm, e.g., about 14 mm.

In some embodiments, the article/consumable may further include an aerosol cooling element adapted to cool the aerosol generated (by heat exchange) from the aerosol-forming substrate before it is inhaled by the user.

The aerosol cooling element is located downstream from the aerosol-forming substrate. For example, the aerosol cooling element may be between the aerosol-forming substrate and an upstream filter element, or between two filter elements. The aerosol cooling element may be at least partially (e.g. completely) circumscribed by a (paper) wrap layer.

The aerosol cooling element may be formed from a plastic material selected from the group consisting of polylactic acid (PLA), polyvinyl chloride (PVC), polyethylene (PE), and polyethylene terephthalate (PET). The aerosol cooling element may be formed from a crimped/collected sheet of material to form a high surface area structure with multiple longitudinal channels to maximize heat exchange and cooling of the aerosol.

In a third aspect, there is provided a smoking substitution system comprising an HNB consumable according to the first aspect or an aerosol-forming article according to the second aspect and a device including a heating element.

The device may be an HNB device, i.e. a device adapted to heat an aerosol-forming substrate without combustion.

The device may include a body for housing a heating element. The heating element may include an elongated, e.g., rod, tubular, or blade heating element. The heating element may protrude into or surround a cavity in the body for receiving the article/consumable as described above.

The device (e.g., the main body) may further include a power source, e.g., a (rechargeable) battery, for supplying power to the heating element. The device may further include a control unit for controlling the supply of power to the heating element.

In a fourth aspect, there is provided a method of using a smoking substitution system according to the second aspect, the method comprising:
Inserting an item/consumable into the device;
and heating the item/consumable using the heating element.

In some embodiments, the method includes inserting the article/consumable into a cavity within the body and penetrating a heating element into the article/consumable as the article/consumable is inserted. For example, the heating element can penetrate an aerosol-forming substrate within the article/consumable.

Those skilled in the art will recognize that, unless mutually exclusive, any feature or parameter described in connection with any one of the above aspects may also be applied to any other aspect. Furthermore, unless mutually exclusive, any feature or parameter described herein may be applied to any aspect and/or may be combined with any other feature or parameter described herein.

So that the invention may be understood and further aspects and features thereof may be realized, embodiments illustrating the principles of the invention will now be discussed in more detail with reference to the accompanying drawings.

FIG. 1 illustrates a first embodiment of an HNB consumable. FIG. 2 illustrates a second embodiment of an HNB consumable. FIG. 13 illustrates a third embodiment of an HNB consumable. FIG. 2 illustrates a first embodiment of a device forming an HNB system.

As shown in FIG. 1, the HNB consumable 1 includes an aerosol-forming substrate 2 at the upstream end of the consumable 1.

The aerosol-forming substrate includes reconstituted tobacco, which includes nicotine as a volatile compound.

The aerosol-forming substrate 2 comprises 65% by weight tobacco provided in the form of collected shreds produced from a slurry/paper recon tobacco sheet. The tobacco has 20% by weight of a humectant, such as propylene glycol (PG) or vegetable glycerin (VG), attached thereto and has a moisture content of 7-9% by weight. The aerosol-forming substrate further comprises a cellulose pulp filler and a guar gum binder.

The aerosol-forming substrate 2 is formed in a substantially cylindrical shape such that the consumable resembles a conventional cigarette. The aerosol-forming substrate 2 has a diameter of about 7 mm and an axial length of about 12 mm.

The aerosol-forming substrate 2 is circumscribed by a paper wrap layer 3.

The consumable 1 includes an upstream filter element 4 and a downstream (terminal) filter element 5. The two filter elements 4, 5 are spaced apart by a paper tube spacer 6. Both filter elements 4, 5 are formed from cellulose acetate tow and are wrapped with respective paper plug layers (not shown).

Both filter elements have a substantially cylindrical shape. The diameter of the upstream filter 4 corresponds to the diameter of the aerosol-forming substrate 2. The diameter of the terminal filter element 5 is slightly larger and corresponds to the combined diameter of the aerosol-forming substrate 2 and the wrap layer 3. The upstream filter element is slightly shorter in axial length than the terminal filter element, with an axial length of 10 mm compared to 12 mm for the terminal filter element.

The paper tube spacer 6 is longer than each of the two filter sections and has an axial length of approximately 14 mm.

Each filter element 4, 5 is a hollow filter element having a hollow bore extending in the longitudinal direction. The diameter of the bore in the upstream filter is slightly larger than the diameter of the bore in the terminal filter, having a diameter of 3 mm compared to 2 mm for the terminal filter element.

The paper tube spacer 6 and the upstream filter portion 4 are circumscribed by the wrap layer 3.

The terminal filter element 5 is joined to the upstream element by a circumscribing paper tip layer 7 to form the consumable. The tip layer 7 surrounds the terminal filter portion and has an axial length of about 20 mm, thus overlapping a portion of the paper tube spacer 6.

A flow restrictor element 13 in the form of a foil disc having a single perforation 14 of 1 mm diameter is provided downstream of the upstream filter element 4, i.e. interposed between the upstream filter element 4 and the paper tube spacer 6.

Figure 2 shows a second embodiment of the consumable 1', which is the same as that shown in Figure 1, except that the terminal filter element 5 is a solid filter element and includes a crushable capsule 8 (crush ball) having a shell wall containing liquid menthol or cherry or vanilla flavoring. The capsule 8 is spherical and has a diameter of 3.5 mm. The capsule 8 is positioned in the axial center of the terminal filter portion 5.

Figure 3 shows a third embodiment of consumable 1", which is the same as the first embodiment, except that wrap layer 3 does not completely circumscribe paper tube spacer 6, and therefore an annular gap 9 exists between tip layer 7 and paper tube spacer 6 downstream of the end of wrap layer 3.

Figure 4 shows a first embodiment inserted into an HNB device 10 that includes a rod-shaped heating element (not shown). The heating element protrudes into a cavity 11 within the body 12 of the device.

The consumable 1 is inserted into the cavity 11 of the body 12 of the device 10 so that the heating rod penetrates the aerosol-forming substrate 2. Heating of the reconstituted tobacco in the aerosol-forming substrate 2 is achieved by supplying power to the heating element (e.g., by a rechargeable battery (not shown)). As the tobacco is heated, moisture and nicotine from within the tobacco and humectant are released as vapor and are entrained in the airflow generated by inhalation by the user at the terminal filter portion 5.

After the vapor passes through the upstream filter 4, the nicotine, moisture, and humectant pass through the perforations 14 in the flow restrictor element 13, so they are forced to share the same location, thus resulting in good mixing. Then, within the paper tube spacer 6, the cross-sectional area of the vapor flow path increases, resulting in more efficient mixing of the vapor components.

As the vapor cools within the paper tube spacer 6, it condenses and forms an aerosol containing the volatile compounds for inhalation by the user.

The features disclosed in the above description, or in the following claims, or in the accompanying drawings, are appropriately expressed in their specific form, or in terms of means for performing a disclosed function, or a method or process for obtaining a disclosed result, and may be utilized separately or in any combination of such features to realize the invention in its many and varied forms.

While the present invention has been described in conjunction with the exemplary embodiments set forth above, many equivalent modifications and variations will be apparent to those of ordinary skill in the art given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative rather than limiting. Various changes may be made to the described embodiments without departing from the scope of the invention.

For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purpose of improving the understanding of the reader. The inventors do not wish to be bound by any of these theoretical explanations.

All headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

Throughout this specification, including the claims which follow, unless the context otherwise requires, the words "have," "comprise," and "include," as well as variations such as "having," "comprises," "comprising," and "including," will be understood to imply the inclusion of a stated whole or step, or group of wholes or steps, but not the exclusion of any other whole or step, or group of wholes or steps.

As used herein and in the appended claims, it should be noted that the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, ranges may be expressed as "about" one particular value and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, by use of the prefix "about," when values are expressed as approximations, it will be understood that the particular value forms another embodiment. The term "about" in connection with numerical values is optional and means, for example, ±10%.

The words "preferred" and "preferably" are used herein to refer to embodiments of the invention that may provide certain benefits, under some circumstances. It is to be understood, however, that other embodiments may also be preferred, under the same or different circumstances. Thus, reference to one or more preferred embodiments does not mean or imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the disclosure or the claims.

Claims (13)

An aerosol-forming article comprising an aerosol-forming substrate, an upstream filter element, a spacer element, and a terminal filter element in an axial flow arrangement, wherein at least one of the filter elements is a hollow filter element, and the aerosol-forming article further comprises a flow restrictor element upstream of the terminal filter element and downstream of the aerosol-forming substrate;
the flow restrictor element comprises a disk or rod having at least one axial perforation or channel;
the upstream filter element is a hollow filter element having a bore diameter larger than a diameter of the at least one axial bore or channel of the flow restrictor element;
Aerosol forming articles. 2. The aerosol-forming article of claim 1 , wherein the flow restrictor element has a single perforation or channel at its axial center having a diameter of 0.5 to 1.5 mm. 3. The aerosol-forming article of claim 1 or 2 , wherein the flow restrictor element is formed from a vapor impermeable material. 3. The aerosol-forming article of claim 1 or 2 , wherein the flow restrictor element is formed from extruded tobacco. The aerosol-forming article of claim 1 , wherein the flow restrictor element is provided upstream of the spacer element. The aerosol-forming article of claim 5 , wherein the flow restrictor element is interposed between the upstream filter element and the spacer element. 7. The aerosol-forming article of any one of claims 1 to 6 , wherein the upstream filter element has an aperture greater than 1.5 mm. 8. The aerosol-forming article of claim 1 , wherein the upstream and terminal filter elements are both hollow filter elements. The aerosol-forming article of claim 1 , wherein the aerosol-forming article is a heat-without-burn (HNB) consumable product. 10. A system comprising the aerosol-forming article of any one of claims 1 to 9 and a device comprising a heating element. The system of claim 10 , wherein the device includes a body for housing the heating element, the heating element comprising an elongated heating element. A method of using a system according to claim 10 or 11 , comprising the steps of:
Inserting the aerosol-forming article into the device; and
heating the aerosol-forming article using the heating element. 13. The method of claim 12 , comprising inserting the aerosol-forming article into a cavity in a body of the device and penetrating the heating element into the aerosol- forming article as the aerosol-forming article is inserted.

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