HK40017007B - Cartridge having a susceptor material - Google Patents

Description

The present invention relates to a cartridge for an aerosol-generating system, the cartridge having a susceptor material. The present invention also relates to an aerosol-generating system comprising the cartridge, and a method of assembling the cartridge.

US 2017/055574 A1 describes a cartridge for use with apparatus for heating smokable material to volatilise at least one component of the smokable material, the cartridge comprising: a container defining a cavity, and smokable material located in the cavity. Preferably, the smokable material comprises tobacco. The cartridge also comprises heating material that is heatable by penetration with a varying magnetic field to heat the smokable material.

Aerosol-generating systems, such as e-cigarettes, that operate by heating a liquid formulation to generate an aerosol for inhalation by users are widely used. Typically they comprise a device portion and a cartridge. In some systems, the device portion contains a power supply and control electronics and the cartridge contains a liquid reservoir holding the liquid formulation, a heater for vaporising the liquid formulation, and a wick that transports the liquid from the liquid reservoir to the heater. While this type of system has become popular, it does have several disadvantages. One disadvantage is the potential for leakage of the liquid from the liquid reservoir both during transport and storage, and when the cartridge is connected to the device portion. The use of a wick to transport the liquid from the reservoir to the heater may add complexity to the system. Another disadvantage is the increased cost of the cartridge resulting from the incorporation of the heater within the cartridge.

It would be desirable to address at least some of these disadvantages with known aerosol-generating systems.

According to a first aspect of the present invention there is provided a cartridge for an aerosol-generating system, the cartridge comprising a container defining a cartridge cavity, a susceptor material positioned within the cartridge cavity, and an aerosol-forming substrate. The susceptor material defines a plurality of interconnected interstices and the aerosol-forming substrate is in the form of a gel that is solid at room temperature, wherein the gel is positioned within the plurality of interconnected interstices.

The term "susceptor" is used herein to refer to a material that is capable of being inductively heated. That is, a susceptor material is capable of absorbing electromagnetic energy and converting it to heat.

The gel is a solid at room temperature. "Solid" in this context means that the gel has a stable size and shape and does not flow. Room temperature in this context means 25 degrees Celsius.

Advantageously, contacting the aerosol-forming substrate with a susceptor material facilitates heating of the aerosol-forming substrate without requiring contact between the aerosol-forming substrate and an electrical heater. For example, the cartridge may be combined with an aerosol-generating device comprising an electrical heater in the form of an induction coil, wherein the induction coil heats the susceptor material by inductive heating. Advantageously, eliminating the need for direct contact between the aerosol-forming substrate and the electrical heater facilitates reuse of the aerosol-generating device with multiple cartridges without contaminating the electrical heater.

Advantageously, providing a susceptor material defining a plurality of interstices, wherein the aerosol-forming substrate is positioned within the plurality of interstices, increases the contact area between the susceptor material and the aerosol-forming substrate. Increasing the contact area between the susceptor material and the aerosol-forming substrate facilitates thermal transfer from the susceptor material to the aerosol-forming substrate. Advantageously, this may minimise the inductive heating of the susceptor material that is required to vaporise the aerosol-forming substrate.

Advantageously, providing a susceptor material with a plurality of interstices that are interconnected facilitates loading of the interstices with the aerosol-forming substrate during manufacture of the cartridge. For example, in embodiments in which the aerosol-forming substrate is inserted into the cartridge cavity in a liquid form, the aerosol-forming substrate may be drawn into the plurality of interconnected interstices by a capillary action.

Advantageously, providing a susceptor material with a plurality of interstices that are interconnected facilitates release of vaporised aerosol-forming substrate from the susceptor material during heating.

Advantageously, providing the aerosol-forming substrate in the form of a gel that is solid at room temperature facilitates retention of the aerosol-forming substrate within the plurality of interconnected interstices prior to heating of the susceptor material. That is, the aerosol-forming substrate cannot flow out of the plurality of interconnected interstices while the aerosol-forming substrate remains in a gel form.

Preferably, the susceptor material comprises a ferromagnetic metallic material. The susceptor material may comprise at least one of ferritic iron, ferromagnetic steel, stainless steel, and aluminium. Different materials will generate different amounts of heat when positioned within electromagnetic fields having similar values of frequency and field strength. Therefore, the susceptor material may be selected to provide a desired power dissipation within a known electromagnetic field.

In embodiments in which the susceptor material comprises stainless steel, the susceptor material may comprise at least one 400 series stainless steel. Suitable 400 series stainless steels include grade 410, grade 420, and grade 430.

The susceptor material may comprise a metallic wool. The metallic wool may be formed from any of the metallic susceptor materials described herein. Preferably, the metallic wool comprises a bundle of metallic filaments, wherein spaces between the metallic filaments form the plurality of interconnected interstices.

The susceptor material may comprise a metallic foam. The metallic foam may be formed from any of the metallic susceptor materials described herein. Preferably, the metallic foam is an open-cell foam, wherein the open cells form the plurality of interconnected interstices.

The susceptor material may comprise a protective coating encapsulating the surface of the susceptor material. The protective coating may prevent direct contact between the susceptor material and the aerosol-forming substrate positioned within the plurality of interconnected interstices. Advantageously, this may prevent undesirable chemical reactions between the susceptor material and the aerosol-forming substrate. The protective coating may comprise at least one of a glass and a ceramic.

Preferably, the cartridge cavity is a blind cavity having a closed end and an open end. Advantageously, providing a blind cartridge cavity may facilitate filling of the cartridge cavity with the susceptor material and the aerosol-forming substrate during manufacture of the cartridge.

Preferably, the cartridge further comprises a seal extending across the open end of the cartridge cavity so that the susceptor material and the aerosol-forming substrate are sealed within the cartridge cavity by the seal. The seal may comprise at least one of a polymeric film and a foil. The seal may comprise a metallic material. The seal may be secured to the container with at least one of an adhesive and a weld, such as an ultrasonic weld. The seal may be secured to the container about a periphery of the open end of the cartridge cavity.

The seal may comprise at least one frangible barrier. In embodiments in which the seal comprises a frangible barrier, the cartridge may be configured for use with an aerosol-generating device comprising a piercing element for rupturing the frangible barrier.

The seal may comprise at least one removable barrier.

The seal may comprise a vapour permeable element configured to allow the release of vapour from the cartridge cavity through the vapour permeable element. The vapour permeable element may comprise at least one of a membrane or a mesh.

The seal may comprise a pressure activated valve that allows for the release of vapour through the valve when a pressure difference across the valve exceeds a threshold pressure difference.

Preferably, the gel is a thermoreversible gel. The term "thermoreversible" is used herein to mean that the gel will become fluid when heated to a melting temperature and will set into a gel again at a gelation temperature. The gelation temperature is preferably at or above room temperature and atmospheric pressure. Atmospheric pressure means a pressure of 1 atmosphere. The melting temperature is preferably higher than the gelation temperature.

Preferably, the gel has a melting temperature of at least about 50 degrees Celsius, more preferably at least about 60 degrees Celsius, more preferably at least about 70 degrees Celsius, more preferably at least about 80 degrees Celsius. The melting temperature in this context means the temperature at which the gel is no longer solid and begins to flow.

Preferably, the gel comprises a gelling agent. The gel may comprise at least one of agar, agarose, or sodium alginate. The gel may comprise Gellan gum. The gel may comprise a mixture of materials. The gel may comprise water.

The gel may comprise an aerosol-former. As used herein, the term "aerosol-former" refers to any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. An aerosol-former is substantially resistant to thermal degradation at the operating temperature of the cartridge. Suitable aerosol-formers are well known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, 1,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as triethylene glycol, 1,3-butanediol and, most preferred, glycerine or polyethylene glycol.

The gel may comprise at least one of nicotine or a tobacco product. Additionally, or alternatively, the gel may comprise another target compound for delivery to a user. In embodiments in which the gel comprises nicotine, the nicotine may be included in the gel with an aerosol-former. Advantageously, providing the nicotine in the gel can prevent leakage of the nicotine from the cartridge at room temperature when compared to alternative cartridges in which the nicotine is provided in a liquid at room temperature. This is particularly advantageous since nicotine is irritating to the skin and can be toxic.

When agar is used as a gelling agent, the gel preferably comprises between about 0.5 percent and about 5 percent by weight agar, more preferably between about 0.8 percent and about 1 percent by weight agar. The gel may further comprise between about 0.1 percent and about 2 percent by weight nicotine. The gel may further comprise between about 30 percent and about 90 percent by weight glycerine, preferably between about 70 percent and about 90 percent by weight glycerin. A remainder of the gel may comprise water and any flavourings.

When Gellan gum is used as a gelling agent, the gel preferably comprises between about 0.5 percent and about 5 percent by weight Gellan gum. The gel may further comprise between about 0.1 percent and about 2 percent by weight nicotine. The gel may further comprise between about 30 percent and about 99.4 percent by weight glycerin. A remainder of the gel may comprise water and any flavourings.

In one embodiment, the gel comprises 2 percent by weight nicotine, 70 percent by weight glycerol, 27 percent by weight water and 1 percent by weight agar. In another embodiment, the gel comprises 65 percent by weight glycerol, 20 percent by weight water, 14.3 percent by weight tobacco and 0.7 percent by weight agar.

The cartridge may have any suitable shape. Preferably, the cartridge is substantially cylindrical. As used herein with reference to the present invention, the terms "cylinder" and "cylindrical" refer to a substantially right circular cylinder with a pair of opposed substantially planar end faces.

The cartridge may have any suitable size.

The cartridge may have a length of, for example, between about 5 millimetres and about 30 millimetres. In certain embodiments the cartridge may have a length of about 12 millimetres.

The cartridge may have a diameter of, for example, between about 4 millimetres and about 10 millimetres. In certain embodiments the cartridge may have a diameter of about 7 millimetres.

Suitable materials for forming the container include, but are not limited to, metal, aluminium, polymer, polyether ether ketone (PEEK), polyimides, such as Kapton®, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), epoxy resins, polyurethane resins and vinyl resins.

The container may be formed by any suitable method. Suitable methods include, but are not limited to, deep drawing, injection moulding, blistering, blow forming and extrusion.

The cartridge may comprise a mouthpiece configured to allow a user to puff on the mouthpiece to draw aerosol into their mouth or lungs. Where the cartridge comprises a mouthpiece, the mouthpiece may comprise a filter. The filter may have a low particulate filtration efficiency or very low particulate filtration efficiency. Alternatively, the mouthpiece may comprise a hollow tube. The mouthpiece may comprise an airflow modifier, for example a restrictor.

The cartridge may be provided within a mouthpiece tube. The mouthpiece tube may comprise an aerosol-forming chamber. The mouthpiece tube may comprise an airflow restrictor. The mouthpiece tube may comprise a filter. The mouthpiece tube may comprise a cardboard housing. The mouthpiece tube may comprise one or more vapour impermeable elements within the cardboard tube. The mouthpiece tube may have a diameter similar to a conventional cigarette, for example about 7 millimetres. The mouthpiece tube may have a mouth end configured to be placed in a user's mouth for inhalation of aerosol therethrough. The cartridge may be held in the mouthpiece tube, for example at an opposite end to the mouth end.

According to a second aspect of the present invention, there is provided an aerosol-generating system comprising an aerosol-generating device and a cartridge according to the first aspect of the present invention, in accordance with any of the embodiments described herein. The aerosol-generating device comprises a housing defining a device cavity for receiving the cartridge, and an electrical heater comprising an inductive heating element arranged to heat the susceptor material when the cartridge is received within the device cavity. The aerosol-generating device further comprises an electrical power supply and a controller for controlling a supply of electrical power from the electrical power supply to the electrical heater.

The inductive heating element may comprise at least one induction coil extending around at least a portion of the device cavity. The induction coil may extend completely around the device cavity. The induction coil may be wound around the device cavity with a plurality of windings.

The inductive heating element may comprise at least one planar induction coil. Preferably, each planar induction coil comprises a flat spiral induction coil.

As used herein a "flat spiral induction coil" means a coil that is generally planar, wherein the axis of winding of the coil is normal to the surface in which the coil lies. In some embodiments, the flat spiral coil may be planar in the sense that it lies in a flat Euclidean plane. However, the term "flat spiral induction coil" as used herein covers coils that are shaped to conform to a curved plane or other three dimensional surface. For example, a flat spiral coil may be shaped to conform to a cylindrical housing or cavity of the device. The flat spiral coil can then be said to be planar but conforming to a cylindrical plane, with the axis of winding of the coil normal to the cylindrical plane at the centre of the coil. If the flat spiral coil conforms to a cylindrical plane or non-Euclidian plane, preferably, the flat spiral coil lies in a plane having a radius of curvature in the region of the flat spiral coil greater than a diameter of the flat spiral coil.

The power source may be a battery, such as a rechargeable lithium ion battery. Alternatively, the power source may be another form of charge storage device such as a capacitor. The power source may require recharging. The power source may have a capacity that allows for the storage of enough energy for one or more uses of the device. For example, the power source may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes, corresponding to the typical time taken to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power source may have sufficient capacity to allow for a predetermined number of puffs or discrete activations.

Preferably, the controller and the electrical power supply are configured so that, during, use, a high frequency oscillating current is passed through the inductive heating element to generate an alternating magnetic field that induces a voltage in the susceptor material. As used herein, a "high frequency oscillating current" means an oscillating current having a frequency of between about 125 kilohertz and about 30 megahertz. The high frequency oscillating current may have a frequency of between about 1 megahertz and about 30 megahertz, preferably between about 1 megahertz and about 10 megahertz and more preferably between about 5 megahertz and about 7 megahertz.

Preferably, the aerosol-generating device is portable. The aerosol-generating device may have a size comparable to a conventional cigar or cigarette. The aerosol-generating device may have a total length between approximately 30 millimetres and approximately 150 millimetres. The aerosol-generating device may have an external diameter between approximately 5 millimetres and approximately 30 millimetres.

According to a third aspect of the present invention, there is provided a method of assembling a cartridge for an aerosol-generating system, the method comprising providing a container defining a cartridge cavity and inserting a susceptor material into the cartridge cavity, the susceptor material defining a plurality of interconnected interstices. The method also comprises inserting a liquid aerosol-forming substrate into the cartridge cavity and gelating the liquid aerosol-forming substrate to form a gel that is solid at room temperature, wherein the gel is positioned within the plurality of interconnected interstices. Preferably, the cartridge is a cartridge according to the first aspect of the present invention, in accordance with any of the embodiments described herein.

The term "gelating" is used herein to refer to the conversion of a liquid into a gel.

Advantageously, inserting the aerosol-forming substrate into the cartridge cavity in a liquid form facilitates flow of the aerosol-forming substrate into the plurality of interconnected interstices. For example, the liquid aerosol-forming substrate may be drawn into the plurality of interconnected interstices by a capillary action.

Preferably, during the step of inserting the liquid aerosol-forming substrate into the cartridge cavity, the liquid aerosol-forming substrate is at an elevated temperature above room temperature. Preferably, the liquid aerosol-forming substrate is at a temperature of at least about 50 degrees Celsius.

The step of gelating the liquid aerosol-forming substrate may comprise cooling the liquid aerosol-forming substrate. In embodiments in which the liquid aerosol-forming substrate is inserted into the cartridge cavity at an elevated temperature, preferably the liquid aerosol-forming substrate is cooled to room temperature during the gelating step. Preferably, the gel is a thermoreversible gel, as described herein with respect to the first aspect of the present invention. Preferably, the liquid aerosol-forming substrate comprises a gelling agent, as described herein with respect to the first aspect of the present invention.

Preferably, the cartridge cavity is a blind cavity having a closed end and an open end. Preferably, the method further comprises positioning a seal across the open end of the cartridge cavity and sealing the seal to the container so that the susceptor material and the gel are sealed within the cartridge cavity by the seal. The seal may be positioned across the open end of the cartridge cavity before or after the gelating step. The seal may comprise any of the optional or preferred features described herein with respect to the first aspect of the present invention.

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

• Figure 1 shows a cross-sectional view of a cartridge according to an embodiment of the present invention;
• Figure 2 shows a side view of an aerosol-generating system according to an embodiment of the present invention;
• Figure 3 shows a cross-sectional view of the aerosol-generating system of Figure 2; and
• Figure 4 shows a flow diagram illustrating a method of assembling a cartridge according to an embodiment of the present invention.

Figure 1 shows a cross-sectional view of a cartridge 10 according to an embodiment of the present invention. The cartridge 10 comprises a container 12 defining a cartridge cavity 14 having an open end 16 and a closed end 18. Positioned within the cartridge cavity 14 is a susceptor material 20 that defines a plurality of interconnected interstices 22. In the embodiment shown in Figure 1 the susceptor material 20 comprises steel wool and the spaces between filaments of the steel wool form the plurality of interconnected interstices 22.

An aerosol-forming substrate 24 is also positioned within the cartridge cavity 14, the aerosol-forming substrate 24 positioned within the plurality of interconnected interstices 22 of the susceptor material 20. At room temperature, the aerosol-forming substrate 24 is in the form of a gel, which prevents the aerosol-forming substrate 24 flowing out of the plurality of interconnected interstices 22. The gel is a thermoreversible gel so that heating the gel to at least 50 degrees Celsius melts the gel such that the aerosol-forming substrate 24 has a liquid form.

The cartridge 10 also comprises a seal 26 extending across the open end 16 of the cartridge cavity 14, the seal comprising a frangible barrier and secured to the container 12 about a periphery of the open end 16 by an ultrasonic weld.

Figures 2 and 3 show an aerosol-generating system 100 according to an embodiment of the present invention. The aerosol-generating system 100 comprises the cartridge 10 of Figure 1, a mouthpiece 102 having a piercing element 104 extending therefrom, and an aerosol-generating device 106. Figure 2 shows the mouthpiece 102 separated from the aerosol-generating device 106 and Figure 3 shows the mouthpiece 102 connected to the aerosol-generating device 106.

The aerosol-generating device 106 comprises a housing 108 defining a device cavity 110 for receiving the cartridge 10. When the cartridge 10 is received within the device cavity 110 and the mouthpiece 102 is connected to the aerosol-generating device 106, the piercing element 104 ruptures the seal 26 of the cartridge 10 so that at least a portion of the piercing element 104 is received within the cartridge cavity 14.

The aerosol-generating device 106 also comprises an electrical heater comprising an inductive heating element 112. The inductive heating element 112 comprises an induction coil positioned within the housing 108 and wrapped around the device cavity 110. Also positioned within the housing 108 are a controller 114 and an electrical power supply 116. During use, the controller 114 controls a supply of an oscillating electrical current from the electrical power supply 116 to the inductive heating element 112. The oscillating electrical current within the inductive heating element generates an alternating magnetic field that induces a voltage within the susceptor material 20 of the cartridge 10. The induced voltage heats the susceptor material 20, which heats the aerosol-forming substrate 24. The heated aerosol-forming substrate melts and vaporises to form a vapour within the cartridge cavity 14. A user may draw on the mouthpiece 102 to draw air into the aerosol-generating system 100 via an airflow inlet 118. The air entering the airflow inlet 118 flows into the cartridge cavity 14 via a first airflow aperture in the piercing element 104, and out of the cartridge cavity 14 via a second airflow aperture in the piercing element 104. As the air flows through the cartridge cavity 14, the vaporised aerosol-forming substrate 24 is entrained in the airflow. The airflow and the vapour entrained therein flow from the second airflow aperture to the user's mouth via an airflow outlet 120 in the mouthpiece 102.

Figure 4 shows a method 200 of assembling a cartridge for an aerosol-generating system, in accordance with an embodiment of the present invention. In a first step 202 a container is provided, the container defining a cartridge cavity. In a second step 204, a susceptor material is inserted into the cartridge cavity. The susceptor material defines a plurality of interconnected interstices. In a third step 206, a liquid aerosol-forming substrate is inserted into the cartridge cavity so that the liquid aerosol-forming substrate is positioned within the plurality of interconnected interstices. In a fourth step 208, the liquid aerosol-forming substrate is gelated to form a gel. In a fifth step 210, a seal is positioned across an open end of the cavity. In a sixth step 212, the seal is sealed to the container.

Claims (15)

1. A cartridge (10) for an aerosol-generating system (100), the cartridge (10) comprising:

   a container (12) defining a cartridge cavity (14);

   a susceptor material (20) positioned within the cartridge cavity (14), the susceptor material (20) defining a plurality of interconnected interstices (22); and

   an aerosol-forming substrate (24) in the form of a gel that is solid at room temperature, wherein the gel is positioned within the plurality of interconnected interstices (22).
2. A cartridge (10) according to claim 1, wherein the susceptor material (20) comprises a ferromagnetic metallic material.
3. A cartridge (10) according to claim 1 or 2, wherein the susceptor material (20) comprises at least one of ferritic iron, ferromagnetic steel, stainless steel, and aluminium.
4. A cartridge (10) according to claim 1, 2 or 3, wherein the susceptor material (20) comprises a metallic wool.
5. A cartridge (10) according to claim 4, wherein the metallic wool comprises a bundle of metallic filaments, and wherein spaces between the metallic filaments form the plurality of interconnected interstices (22).
6. A cartridge (10) according to any preceding claim, wherein the susceptor material (20) comprises a metallic foam.
7. A cartridge (10) according to claim 6, wherein the metallic foam is an open-cell foam, and wherein the open cells form the plurality of interconnected interstices (22).
8. A cartridge (10) according to any preceding claim, wherein the cartridge cavity (14) is a blind cavity having a closed end (18) and an open end (16).
9. A cartridge (10) according to claim 8, further comprising a seal (26) extending across the open end (16) of the cartridge cavity (14) so that the susceptor material (20) and the aerosol-forming substrate (24) are sealed within the cartridge cavity (14) by the seal (26).
10. A cartridge (10) according to any preceding claim, wherein the gel is a thermoreversible gel.
11. A cartridge (10) according to any preceding claim, wherein the gel has a melting temperature of at least 50 degrees Celsius.
12. A cartridge (10) according to any preceding claim, wherein the gel comprises at least one of nicotine or a tobacco product.
13. An aerosol-generating system (100) comprising:

    a cartridge (10) according to any preceding claim; and

    an aerosol-generating device (106) comprising:

    a housing (108) defining a device cavity (110) for receiving the cartridge (10);

    an electrical heater comprising an inductive heating element (112) arranged to heat the susceptor material (20) when the cartridge (10) is received within the device cavity (110);

    an electrical power supply (116); and

    a controller (114) for controlling a supply of electrical power from the electrical power supply (116) to the electrical heater.
14. A method of assembling a cartridge (10) for an aerosol-generating system (100), the method comprising:

    providing a container (12) defining a cartridge cavity (14);

    inserting a susceptor material (20) into the cartridge cavity (14), the susceptor material (20) defining a plurality of interconnected interstices (22);

    inserting a liquid aerosol-forming substrate (24) into the cartridge cavity (14); and

    gelating the liquid aerosol-forming substrate (24) to form a gel that is solid at room temperature, wherein the gel is positioned within the plurality of interconnected interstices (22).
15. A method according to claim 14, wherein the cartridge cavity (14) is a blind cavity having a closed end (18) and an open end (16), the method further comprising:

    positioning a seal (26) across the open end (16) of the cartridge cavity (14); and

    sealing the seal (26) to the container (12) so that the susceptor material (20) and the gel are sealed within the cartridge cavity (14) by the seal (26).