RU2822507C1 - Heating element having heat-conducting and capillary threads - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to a heating element for an aerosol generating system. Technical result is achieved by the fact that heating element (10) for the aerosol generating system comprises a plurality of first threads (16) and a plurality of second threads (18). Plurality of first threads (16) is configured to heat the aerosol-forming liquid substrate, and the plurality of second threads (18) is configured to carry the aerosol-forming liquid substrate for wetting at least a portion of heating element (10) with the liquid substrate. Multiple first threads (16) are in the first direction, and multiple second threads (18) are located in the second direction, and the second direction is transverse to the first direction.

EFFECT: providing improved wetting of the heating element with a liquid substrate.

12 cl, 11 dwg, 1 tbl

Description

The present invention relates to a heating element for an aerosol generating system. Particularly, but not exclusively, the present invention relates to a heating element for a hand held electrical aerosol generating system, which is configured to heat a liquid aerosol-forming substrate to generate an aerosol and deliver the aerosol to the user's mouth. The present invention also relates to a heater assembly for an aerosol generating system containing a heating element, a cartridge for an aerosol generating system, an aerosol generating system, and a method for manufacturing a heating element.

Hand-held electrical aerosol-generating devices and systems are known that consist of a device-like portion comprising a battery and control electronics, a portion for containing or receiving a liquid aerosol-forming substrate, and an electrical heater assembly for heating the aerosol-forming substrate to generate aerosol. The heater assembly typically includes a heating element in the form of a coil of wire that is wound around an elongated wick that transfers the aerosol-forming liquid substrate from the liquid storage portion to the heater. In use, an electrical current may be passed through a coil of wire to heat the heater assembly and thereby generate an aerosol from the aerosol-forming liquid substrate. There is also a mouthpiece through which the user can draw the aerosol into the mouth.

It is desirable that aerosol generating systems be capable of producing an aerosol that remains constant over a number of successive uses of the system and remains constant across different aerosol generating systems of the same type. Variations in the quality and quantity of aerosol generated can impair the user experience. In particular, it is desirable to reduce the likelihood of a "dry heating" situation occurring, i.e., a situation in which the heating element heats up when there is insufficient presence of aerosol-forming liquid substrate. This situation is also known as a “dry puff” and can result in overheating and potentially thermal decomposition of the liquid aerosol-forming substrate, which can result in the formation of unwanted by-products.

To produce a continuous aerosol, the heating element needs to be constantly wetted by the liquid aerosol-forming substrate each time the user draws from the aerosol-generating system. However, with traditional wick and coil heaters it can be difficult to achieve consistent wetting due to variation between different wicks. Wetting of the heating element also depends on the orientation of the aerosol generating system and the amount of aerosol-forming substrate remaining in the liquid storage portion.

In addition, the ability to produce heater assemblies well and consistently is important to maintaining reliable operation of different aerosol generating systems of the same type. For example, in heater assemblies that have a heating coil, the heating coils must be manufactured to uniform dimensions to reduce variation between products. In prior art systems, manufacturing the heater assembly may require a large number of manufacturing steps, some of which may require a worker to perform them manually. Manual assembly increases the likelihood of variation between different heater assemblies and also increases the cost and complexity of the manufacturing process.

It is desirable to provide a heating element for the aerosol generating system that allows for more consistent wetting of the heating element. It is also desirable to provide a heating element that can be manufactured in a simpler and more uniform manner.

According to one example of the present invention, a heating element is provided for an aerosol generating system. The heating element may include a first filament. The first thread may be configured to heat the liquid substrate to form an aerosol. The heating element may include a second filament. The second filament may be configured to carry a liquid aerosol-forming substrate to wet at least a portion of the heating element with the liquid aerosol-forming substrate.

According to one example of the present invention, a heating element is provided for an aerosol generating system. The heating element may comprise a plurality of first filaments. The plurality of first filaments may be configured to heat the liquid substrate to form an aerosol. The heating element may include a plurality of second filaments. The plurality of second filaments may be configured to carry a liquid aerosol-forming substrate to wet at least a portion of the heating element with the liquid aerosol-forming substrate.

According to one example of the present invention, there is provided a heating element for an aerosol generating system, the heating element comprising a plurality of first filaments and a plurality of second filaments, the plurality of first filaments configured to heat a liquid aerosol-generating substrate; and wherein the plurality of second filaments are configured to carry the liquid aerosol-forming substrate to wet at least a portion of the heating element with the liquid aerosol-forming substrate.

Thus, the heating element is a hybrid heating element containing two different types of filament; wherein the plurality of first threads is configured to heat the liquid aerosol-forming substrate, and the plurality of second threads is configured to carry the liquid aerosol-forming substrate. As an advantage, the plurality of second threads carries the aerosol-forming liquid substrate to and along the first threads. Thus, the second filaments serve as wicks within the body of the heating element and help wet the heating element with the liquid aerosol-forming substrate by increasing the area of the first filaments that is in contact with the liquid aerosol-forming substrate. The second filaments assist in distributing the aerosol-forming substrate over the heating element to achieve better wetting of the first filaments and increase the evaporation area. The heating element of the present invention helps to provide a constant area of the heating element that is wetted during each use of the aerosol generating system, and thus helps to generate a constant amount of aerosol over a number of successive uses and for different aerosol generating systems of the same type. The second threads may also help improve the incorporation of the heating element into a porous material or other form of transfer material used to transfer the aerosol-forming liquid substrate to the heating element. In addition, the second filaments help to increase the contact area between the heating element and the transfer material.

The heating element may be a fluid-permeable heating filament. The first filaments may be heating filaments. The second threads may be capillary threads.

The plurality of first threads may be formed from an electrically conductive material. The electrically conductive material allows the heating element to be resistively or inductively heated.

The plurality of first filaments may include electrically resistive heating filaments.

The plurality of first threads may be formed from a metallic material. The plurality of first threads may be made from any suitable electrically conductive material. Suitable materials include, but are not limited to: semiconductors such as doped ceramics, electrically conductive ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made from ceramic material and metallic material. Such composite materials may contain alloyed or unalloyed ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and platinum group metals. Examples of suitable metal alloys include stainless steel, constantan, nickel, cobalt, chromium, aluminum, titanium, zirconium, hafnium, niobium, molybdenum, tantalum, tungsten, tin, gallium, manganese - and iron-containing alloys, as well as superalloys based on nickel, iron, cobalt, stainless steel, Timetal®, alloys based on iron and aluminum, as well as alloys based on iron, manganese and aluminum. Timetal® is a registered trademark of Titanium Metals Corporation. Preferably, the plurality of first threads is made of stainless steel, more preferably 300 series stainless steel such as AISI 304, 312, 316, 304L, 316L, or 400 series stainless steel such as AISI 410, 420 or 430.

Additionally, the plurality of first threads may comprise combinations of the materials described above. A combination of materials can be used to improve resistance control of the heating element. For example, materials with high intrinsic resistance can be combined with materials with low intrinsic resistance. This may be advantageous if one of the materials is preferred for other reasons, such as cost, processability, or other physical and chemical parameters. Advantageously, high resistivity heaters enable more efficient use of battery energy.

The plurality of first threads may include wires. The plurality of first threads may include electrically conductive threads.

The plurality of second strands may be hydrophilic. The plurality of second threads may be made of a hydrophilic material. Alternatively, the plurality of second threads may be made of a different material and coated with a hydrophilic material. A hydrophilic material has an affinity for water and is more easily wetted by aqueous solutions compared to non-hydrophilic materials. The hydrophilic second filament helps carry the aerosol-forming liquid substrate within the heating element to wet the heating element.

The plurality of second threads may be formed from a metallic material. The plurality of second threads may be formed from a non-metallic material. The plurality of second strands may be made of or coated with any suitable hydrophilic material. Suitable materials include, but are not limited to: polymers such as polyesters; cellulosic fibers such as cotton, rayon or other regenerated fibers made from wood and agricultural products; glass; ceramics and composite materials made from a combination of the above materials. In one example, the second threads may be made from a ductile material such as rayon, as opposed to more fragile materials such as glass, since ductile materials are more flexible and more suitable for mass production techniques.

The plurality of second threads may be fibrous. Each of the second threads may include one or more fibers. Each of the second threads may include a thread. The plurality of second threads may include fiberglass threads.

The plurality of second strands may be formed from a non-hydrophilic material or even from a hydrophobic material with a surface treated to increase the hydrophilicity of the material. Any suitable surface treatment that increases the surface energy of the material can be used, including, but not limited to, plasma treatment and sandblasting. In one example, the second filaments may be made of polyetheretherketone (PEEK), which is surface treated to make it hydrophilic and increase its wettability. The advantage of using PEEK filaments is that they can be used to incorporate a heating element into a heater mount that is also made of PEEK or other suitable polymer. By placing the heating element on the PEEK heater mount and heating both of them to at least the glass transition temperature of the PEEK, the PEEK strands of the heating element will bind to the PEEK heater mount and hold the heating element to the heater mount.

The plurality of first filaments may include induction heating filaments such that the plurality of first filaments are inductively heated when the heating element is placed in an alternating magnetic field. The plurality of first threads are preferably aligned with or substantially parallel to the direction of the alternating magnetic field.

The plurality of first threads may be formed from a current-receiving material. As used herein, the term "susceptible material" refers to a material that is capable of converting magnetic energy into heat. When the pantograph is placed in an alternating magnetic field, such as an alternating magnetic field generated by an induction coil, the pantograph heats up. Heating of the current collector may result from at least one of hysteresis losses and eddy currents induced in the current collector material, depending on the electrical and magnetic properties of the current collector material.

The current collector may be or may contain any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Preferred current collecting materials may be heated to temperatures in excess of 100, 150, 200 or 250 degrees Celsius. Preferred current collecting materials may be electrically conductive materials. Suitable current collecting materials include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel compounds, titanium and composite metal materials. Preferred current collecting materials may contain metal or carbon. Some preferred current collecting materials may be ferromagnetic, such as ferritic iron, a ferromagnetic alloy such as ferromagnetic steel or stainless steel, ferromagnetic particles and ferrite. The current collecting material may contain at least 5 percent, at least 20 percent, at least 50 percent, or at least 90 percent ferromagnetic or paramagnetic materials. Preferred current collecting materials may contain or be made from 400 series stainless steel, such as AISI 410, 420 or 430. Different materials will dissipate different amounts of energy when placed within electromagnetic fields having similar frequencies and field strengths. Thus, parameters of the current collector material, such as material type and size, can be changed to provide the desired power dissipation within a known electromagnetic field.

In one example, the plurality of first threads may be formed from a magnetic metallic material. The plurality of second strands may be formed from a non-metallic hydrophilic material. The heating element may further comprise a plurality of third filaments that are formed from a non-magnetic metallic material. Advantageously, by providing a plurality of third filaments formed from a non-magnetic material, a portion of the heating element is provided that is not inductively heated to a significant degree when placed in an alternating magnetic field, since the non-magnetic material does not generate a significant amount of heat compared to the magnetic material. This occurs because non-magnetic materials are heated due to eddy currents in the material, in particular, in the area of the material near its surface (the so-called “skin” effect), and magnetic materials are heated due to eddy currents in the “skin” layer and due to losses on hysteresis in magnetic material. Additional hysteresis losses in magnetic materials help generate more heat. For example, when stainless steel strands are placed in an alternating magnetic field with a frequency of approximately 6.78 megahertz and a field strength of approximately 1 to 10 amperes per meter, magnetic stainless steel generates approximately 10 times more heat than non-magnetic stainless steel. Multiple third strands may have a structural function. For example, the plurality of third filaments may form a portion of the heating element that is connected to or in contact with the heater mount or grid holder. This arrangement reduces the amount of heat from the heating element that is dissipated into the heater mount and also reduces the likelihood of heat damage to the heater mount. The frequency and field strength of the magnetic field can be adjusted depending on the materials used.

In another example, the plurality of first threads may be formed from a magnetic metallic material. The plurality of second threads may be formed from a magnetic metal material. The heating element may further comprise a plurality of third filaments that are formed from a non-magnetic metallic material. The plurality of third threads may extend in the same direction as the plurality of second threads. The plurality of third filaments may be arranged in two parts or groups on opposite sides of the heating element. The plurality of third filaments may form a portion of the heating element that is connected to or in contact with the heater mount or grid holder. The plurality of second heating elements may form a portion of the heating element that is located within or across the opening or channel of the heater or grid holder attachment. The plurality of second and third threads may be more closely spaced or denser than the plurality of first threads. Each strand of the plurality of second strands may be in contact with an adjacent strand of the plurality of second strands at one or more points along its length. Each strand of the plurality of third strands may be in contact with an adjacent strand of the plurality of third strands at one or more points along its length.

The plurality of first threads can be made from 400 series stainless steel, such as AISI 410, 420 or 430. 400 series stainless steel is usually magnetic. A variety of third strands can be made from 300 series stainless steel grades such as AISI 304, 312, 316, 304L, 316L. 300 series stainless steel is generally non-magnetic.

Each of the second threads may extend along a corresponding one of the first threads to help carry or draw the aerosol-forming liquid substrate along the first thread. Each of the second strands may extend in a space between two adjacent first strands to help carry or draw an aerosol-forming liquid substrate into the spaces between the adjacent first strands and along the first strands. Each of the second threads may substantially fill a gap between two adjacent first threads. The second filament can carry the liquid substrate forming an aerosol by capillary effect or capillarity. The second filament can transport a liquid substrate forming an aerosol by capillary effect or capillarity within the body of the filament itself, for example, between the fibers of the second filament. Alternatively or additionally, the space between the first filament and the second filament may act as a capillary channel that carries a liquid substrate forming an aerosol.

The plurality of first threads and the plurality of second threads may extend in the same direction. A plurality of first threads and a plurality of second threads may be intertwined. By “interlaced” is meant that a plurality of first threads and a plurality of second threads are arranged in a sequence alternating between the first and second threads. A plurality of first threads and a plurality of second threads may be arranged parallel to each other. This arrangement helps to transfer or draw the aerosol-forming liquid substrate into the spaces between and along the first filaments, which in turn helps wet the heating element. As a result, the area of the first filaments that is in contact with the aerosol-forming liquid substrate is increased, which promotes evaporation of the aerosol-forming liquid substrate.

The heating element may comprise a sequence of filaments or a web of filaments. In one example, a plurality of first threads may be arranged to form a mesh. As used herein, the term "mesh" refers to a network of filaments that has a plurality of pores or cells. The mesh may comprise a portion of the plurality of first threads located in a first direction and another portion of the plurality of first threads located in a second direction. The second direction may be transverse to the first direction. The second direction may be substantially perpendicular to the first direction. Individual strands of the plurality of second strands may be located between at least some of the first strands. The individual threads of the plurality of second threads may be located in at least one of the first or second directions. With this arrangement, the second filaments can help carry or draw the aerosol-forming liquid substrate into the pores or cells in the mesh of the first filaments and along the first filaments, which in turn helps wet the heating element.

The plurality of second threads may be located in only one of the first and second directions. The plurality of second threads may be located in both the first and second directions. A plurality of second threads may be positioned between a plurality of first threads such that each space between adjacent threads of the plurality of first threads contains a second thread.

In another example, the heating element may be arranged in such a way that it forms a grid. A plurality of first threads may be arranged in a first direction. A plurality of second threads may be located in the second direction. The second direction may be transverse to the first direction. The second direction may be substantially perpendicular to the first direction. This arrangement helps to transfer or draw the aerosol-forming liquid substrate into the heating element, which in turn helps wet the heating element.

The mesh can be woven or non-woven. The mesh can be formed using various types of woven or lattice structures.

The heating element may comprise an interlocking mesh. Weaving multiple first threads and multiple second threads helps increase the strength of the mesh. In addition, the interlacing mesh causes at least one of the plurality of first threads and the plurality of second threads to have a wave-like configuration when it is intertwined with the other plurality of threads. Such a wave-like configuration can facilitate the inclusion of a heating element in the transfer material since the wave-like portions of the filaments can be embedded in the transfer material.

When the heating element includes an interlocking mesh, the first thread direction may be a grain direction and the second thread direction may be a cross thread direction.

In an example in which the heating element filaments are made of the same material, the filaments located in the cross filament direction may have a diameter and thickness equal to or less than the diameter and thickness of the filaments located in the lobe filament direction. This arrangement results in the transverse threads being at least as flexible and deformable, and preferably more flexible and deformable, than the lobe threads. This ensures that the transverse threads are woven around the lobar threads.

In another example, in which the heating element contains both metallic and non-metallic filaments, the metallic filaments may be longitudinal and the non-metallic filaments may be transverse. In this case, non-metallic threads can be selected to be more flexible and deformable than metallic threads. This ensures that the transverse threads are woven around the lobar threads.

The mesh heating element may include a plurality of first filaments formed from a magnetic metal material. The mesh heating element may include a plurality of second filaments formed from a magnetic metal material. The mesh heating element may further comprise a plurality of third filaments formed from a non-magnetic metallic material such that the plurality of third filaments are not inductively heated to a significant degree when placed in an alternating magnetic field. A plurality of third threads may be woven in the same direction as the plurality of second threads. The plurality of third strands may define at least one portion of the heating element that is connected to or in contact with the heater mount or grid holder. This arrangement reduces heat loss from the heater mounting. The plurality of second heating elements may be included in a portion of the heating element that is located within or across the opening or passage of the heater or grid holder. The plurality of second and third threads may be more closely spaced or denser than the plurality of first threads. Each strand of the plurality of second strands may be in contact or in contact with an adjacent strand of the plurality of second strands at one or more points along its length. Each strand of the plurality of third strands may be in contact or in contact with an adjacent strand of the plurality of third strands at one or more points along its length. By placing multiple second and third threads in contact with each other, no gaps will be visible between the threads when viewed at an angle perpendicular to the plane of the mesh. This dense mesh pattern helps transport the aerosol-forming liquid substrate across the mesh.

The plurality of first threads may define pores or cells between the threads, and the pores may have a width of from 10 micrometers to 300 micrometers, preferably from 20 micrometers to 100 micrometers, preferably from 50 micrometers to 100 micrometers, more preferably about 70 micrometers.

The plurality of first threads can form a mesh ranging from 60 to 240 threads per centimeter (+/- 10 percent). Preferably, the mesh density is from 100 to 140 threads per centimeter (+/- 10 percent). More preferably, the mesh density is approximately 115 threads per centimeter.

The percentage of open area of the mesh, which is the ratio of the area of the pores or cells to the total area of the mesh, can be from 40 percent to 90 percent, preferably from 85 percent to 80 percent, more preferably about 82 percent.

Each of the first heating element filaments or wires may have an average diameter of at least 10, 16, 17, 25 or 30 microns. Each of the first filaments or wires may have an average diameter of less than 100, 90, 80, 70, 60, 50, 40 or 30 microns. Each of the first filaments or wires may have an average diameter of from 10 to 80 microns, preferably from 10 to 50 microns, and more preferably from 15 to 30 microns, for example about 25 microns.

The plurality of second threads may have a deformed or flattened cross-sectional profile. Each of the second threads may have a width that is approximately equal to the mesh size such that the second thread occupies substantially all or at least 80 percent of the space between adjacent first threads. Each of the second threads may have a thickness that is approximately equal to the diameter or thickness of the first threads.

The second threads or fibers may have an average diameter of from 80% to 120% of the average diameter of the first threads or wires. The first threads and the second threads may have substantially identical average diameters.

Each of the second threads or fibers may have an average diameter of at least 10, 16, 17, 25 or 30 microns. Each of the second threads or fibers may have an average diameter of less than 100, 90, 80, 70, 60, 50, 40, or 30 microns. Each of the second threads or fibers may have an average diameter of from 10 to 80 microns, preferably from 10 to 50 microns, and more preferably from 15 to 30 microns, for example about 25 microns.

The heating element may be substantially flat. The heating element may be substantially planar. As an advantage, the flat or planar heating element can be easily processed during manufacture and can provide a robust heater assembly design.

In the context of this document, the term "flat" is used to refer to an essentially two-dimensional topological manifold. Thus, a flat heating element can extend in two dimensions along the surface significantly more than in the third dimension. The dimensions of a flat heating element in two dimensions within a surface may be at least 2, 5 or 10 times larger than in a third dimension perpendicular to that surface. An example of a substantially planar heating element is a structure between two substantially parallel surfaces, wherein the distance between the two imaginary surfaces is substantially less than the extent within those surfaces. In some examples, a substantially flat heating element may engage the surface of a transfer material, such as a porous ceramic body.

In other examples, the heating element is curved along one or more dimensions, for example, forming a dome shape or a bridge shape.

The area of the heating element may be small, for example less than or equal to 50 square millimeters, preferably less than or equal to 25 square millimeters, more preferably about 15 square millimeters. The size is selected to incorporate the heating element into a hand-held system. A heating element size less than or equal to 50 square millimeters reduces the amount of total power required to heat the heating element while still providing sufficient contact of the heating element with the aerosol-forming liquid substrate. The heating element may, for example, have a rectangular shape and a length of from 2 millimeters to 10 millimeters and a width of from 2 millimeters to 10 millimeters. Preferably, the heating element has dimensions of approximately 5 millimeters by 3 millimeters.

The electrical resistance of the heating element can range from 0.3 Ohm to 4 Ohm. Preferably the electrical resistance is equal to or greater than 0.5 ohms. More preferably, the electrical resistance of the heating element is from 0.6 ohms to 0.8 ohms, and most preferably about 0.68 ohms. The electrical resistivity of the heating element is preferably at least an order of magnitude, and more preferably at least two orders of magnitude, greater than the electrical resistivity of any electrically conductive contact portions. This ensures that the heat generated by the flow of current through the electric heater is localized at the heating element. Advantageously, the heating element has a low overall resistance if the system is powered by a battery. The low resistance, high current system allows high power to be supplied to the heating element. This makes it possible for the heating element to quickly heat the electrically conductive threads to the required temperature.

According to one example of the present invention, a heater assembly is provided for an aerosol generating system. The heater assembly may include a heating element in accordance with any of the examples described above. The heater assembly may include transfer material for transferring the aerosol-forming liquid substrate to the heating element.

According to one example of the present invention, there is provided a heater assembly for an aerosol generating system, the heater assembly comprising a heating element according to any of the examples described above, and a transfer material for transferring a liquid aerosol-generating substrate to the heating element.

The transfer material may comprise capillary material. As used herein, "capillary material" refers to a material that transfers liquid from one end of the material to the other by capillary action. The capillary material may have a fibrous or porous structure. The capillary material preferably comprises a bundle of capillaries. For example, the capillary material may contain a plurality of fibers or threads, or tubes with narrow channels. The fibers or filaments may be generally aligned to move the aerosol-forming liquid substrate in a particular direction, for example, towards a heating element. Alternatively, the capillary material may comprise a sponge-like or foam-like material. The structure of the capillary material forms many small channels or tubes through which the aerosol-forming liquid substrate can be transported by capillary action. The capillary material may extend into pores or cells in the heater. The heater can draw the liquid substrate, forming an aerosol, into the specified pores or cells due to capillary effect.

The transfer material may comprise any suitable material or combination of materials. Examples of suitable materials are sponge or foam material, ceramic or graphite based materials in the form of fibers or sintered powders, foamed metal or plastic material, fiber material, for example made from twisted or extruded fibers such as cellulose acetate, polyester or bonded polyolefin, polyethylene , terylene or polypropylene fibers, nylon fibers or ceramics. The transfer material may have any suitable capillarity and porosity for its use with liquids having different physical properties. The liquid aerosol-forming substrate has physical properties, including, but not limited to, viscosity, surface tension, density, thermal conductivity, boiling point, and vapor pressure, that enable the liquid aerosol-forming substrate to be transferred by the liquid transfer material by capillary action. effect. The transfer material may comprise a porous ceramic body.

Portions of some of the plurality of second threads may be included in the transfer material. Some of the plurality of second filaments may have portions that extend from the plane or body of the heating element, which portions may be included in the transfer material. For example, some of the plurality of second threads may have waveforms or loops or loose ends that may be included or embedded in the transfer material. An advantage of including second filaments in the transfer material is that it helps improve contact between the heating element and the transfer material and transfer of the aerosol-forming liquid substrate to the heating element.

The heating element may be fixedly attached to the transfer material. The heating element may be welded or soldered to the transfer material. The heating element may be attached to the transfer material through bonding portions formed between the second thread portions and the transfer material. Binding sites can be formed by thermal melting. Alternatively, the transfer material may be deposited directly onto the heating element using some type of deposition process, chemical, vapor phase, or electrical.

The heater assembly may further comprise at least two electrical contacts for supplying electrical power to the heating element. Each electrical contact may be coupled to at least one of the plurality of first threads. Each electrical contact may be connected to a plurality of first threads. Each electrical contact may be connected to substantially all of the first threads. Electrical contacts may be connected directly to one or more of the first threads. Electrical contacts may be connected to one or more of the first threads by soldering.

If the heater assembly has a heating element in which electrical contacts are directly connected to one or more of the first filaments, a plurality of first filaments may be located in the direction of the transverse filament. As discussed above, the plurality of first filaments are heating filaments and filaments through which electric current is passed. By arranging a plurality of first threads as cross threads, the wavy nature of the cross threads around the lobe threads helps to bring the first threads into direct connection with the electrical contacts. This helps improve the electrical connection between the heating element and the electrical contacts and reduces heat loss that may be caused by an indirect connection.

Each electrical contact may be coupled to at least one of a plurality of third threads. The electrical contacts may be connected to a portion of the heating element that does not become appreciably hot during use. This reduces the temperature stress on the electrical contacts.

Electrical contacts may be located on opposite ends or sides of the heating element. The electrical contacts may comprise two electrically conductive contact pads. Electrically conductive contact pads may be located in the region of the edge of the heating element. Preferably, at least two electrically conductive contact pads may be located at the edges of the heating element. The electrically conductive pad may include a tin pad. Alternatively, the electrically conductive pad may be integral with the fluid-permeable heating element.

According to one example of the present invention, a cartridge is provided for an aerosol generating system. The cartridge may contain a heater assembly in accordance with any of the examples described above. The cartridge may include a liquid storage portion for holding a liquid aerosol-forming substrate.

According to one example of the present invention, there is provided a cartridge for an aerosol generating system, the cartridge comprising a heater assembly according to any of the examples described above, and a liquid storage portion for holding a liquid aerosol-generating substrate.

The terms “liquid storage portion” and “liquid storage compartment” are used interchangeably herein. The liquid storage portion or compartment may have first and second storage portions in communication with each other. The first storage portion of the liquid storage compartment may be on a side of the heater assembly opposite to the side on which the second storage portion of the liquid storage compartment is located. The aerosol-forming liquid substrate is contained in the first and second portions of the liquid storage compartment.

As an advantage, the first storage portion of the storage compartment is larger than the second storage portion of the liquid storage compartment. The cartridge may be configured to allow a user to draw or suction from the cartridge to inhale an aerosol generated in the cartridge. In use, the mouth end hole of the cartridge is generally positioned above the heater assembly, with the first storage portion of the storage compartment located between the mouth end hole and the heater assembly. Having the first storage portion of the liquid storage compartment above the second storage portion of the liquid storage compartment allows liquid to be delivered from the first storage portion of the liquid storage compartment to the second storage portion of the liquid storage compartment and thus to the heater assembly during use under gravity.

The cartridge may have a mouthpiece end through which a user can draw in the generated aerosol, and a connection end configured to connect to the aerosol generating device, with a first side of the heater assembly facing the mouthpiece end and a second side of the heater assembly facing the connection end. .

The cartridge may define a closed path or passage for air flow from the air inlet opening past a first side of the heater assembly to an opening at the mouth end of the cartridge. The closed passage for air flow may pass through the first or second storage portion of the liquid storage compartment. In one embodiment, the air flow path extends between the first and second storage portions of the liquid storage compartment. In addition, the air flow passage may extend through the first storage portion of the liquid storage compartment. For example, the first storage portion of the liquid storage compartment may have an annular cross-section, with an air flow passage extending from the heater assembly to the mouthpiece portion through the first storage portion of the liquid storage compartment. Alternatively, the air flow passage may extend from the heater assembly to a mouth end opening adjacent the first storage portion of the liquid storage compartment.

The cartridge may contain retention material for retaining the liquid substrate forming an aerosol. The holding material may be provided in the first storage portion of the liquid storage compartment, in the second storage portion of the liquid storage compartment, or in both the first and second storage portions of the liquid storage compartment. The holding material may be foam, sponge, or a collection of fibers. The retaining material may be formed from a polymer or copolymer. In one embodiment, the retention material is a twisted polymer. The aerosol-forming liquid substrate may be released into the containment material during use. For example, the aerosol-forming liquid substrate may be provided in a capsule.

The cartridge has the advantage of containing a liquid substrate that forms an aerosol. As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol. Volatile compounds may be released as a result of heating the substrate, forming an aerosol.

The aerosol-forming substrate may be liquid at room temperature. The aerosol-forming substrate may contain both liquid and solid components. The liquid substrate forming the aerosol may contain nicotine. The liquid substrate that forms the aerosol containing nicotine may be a matrix of nicotine salt. The aerosol-forming liquid substrate may contain material of plant origin. The aerosol-forming liquid substrate may contain tobacco. The liquid aerosol-forming substrate may comprise tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate when heated. The aerosol-forming liquid substrate may comprise homogenized tobacco material. The aerosol-forming liquid substrate may contain non-tobacco material. The aerosol-forming liquid substrate may contain homogenized plant material.

The liquid aerosol-forming substrate may contain one or more aerosol-forming substances. The aerosol forming agent is any suitable known compound or any mixture of compounds which, when used, promotes the formation of a dense and stable aerosol and is substantially resistant to thermal degradation at the operating temperature of the system. Examples of suitable aerosol-forming agents include glycerin and propylene glycol. Suitable aerosol-forming agents are well known in the art and include, but are not limited to: polyhydric alcohols such as triethylene glycol, 1,3-butanediol and glycerol, polyhydric alcohol esters such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The aerosol-forming liquid substrate may contain water, solvents, ethanol, plant extracts, and natural or artificial flavoring agents.

The liquid aerosol-forming substrate may contain nicotine and at least one aerosol-forming agent. The aerosol forming agent may be glycerin or propylene glycol. The aerosol-forming agent may contain both glycerin and propylene glycol. The concentration of nicotine in the liquid aerosol-forming substrate may range from about 0.5% to about 10%, such as about 2%.

The cartridge may include a housing. The body may be made from a molded plastic material such as polypropylene (PP) or polyethylene terephthalate (PET). The housing may partially or completely form the wall of one or both portions of the liquid storage compartment. The housing and the liquid storage compartment can be formed as a single unit. Alternatively, the liquid storage compartment may be provided separately from the housing and connected to the housing.

According to one example of the present invention, an aerosol generating system is provided. The aerosol generating system may comprise a cartridge in accordance with any of the examples described above. The aerosol generating system may comprise an aerosol generating device. The cartridge can be configured to be detachably connected to the aerosol generating device. The aerosol generating device may further comprise a power source for supplying electrical power to the heating element.

According to one example of the present invention, there is provided an aerosol generating system comprising: a cartridge according to any of the examples described above; and an aerosol generating device, wherein the cartridge is releasably coupled to the aerosol generating device, the aerosol generating device including a power source for supplying electrical power to the heating element.

The aerosol generating device may further comprise a control circuit configured to control the supply of electrical power to the heater assembly.

The aerosol generating device may be configured to inductively heat the heating element. The aerosol generating device may include an inductor for inductively heating the heating element. The inductor may be an induction coil.

The control circuit may include a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit (ASIC) or other electronic circuit capable of providing control. The control circuit may contain additional electronic components. For example, in some embodiments, the control circuit may include any of the following: sensors, switches, display elements. Power may be supplied to the heater assembly continuously upon activation of the device, or may be supplied intermittently, such as from puff to puff. Power may be supplied to the heater assembly in the form of pulses of electrical current, such as through pulse width modulation (PWM).

The power source may be a DC power supply. The power source may be a battery. The battery may be a lithium-based battery, such as a lithium cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery. The battery may be a nickel metal hydride battery or a nickel cadmium battery. The power source may be another type of charge storage device, such as a capacitor. The power source may be rechargeable and configured to perform multiple charge and discharge cycles. The power source may have a capacity that allows sufficient energy to be stored for one or more uses by the user; for example, the power source may have sufficient capacity to allow continuous generation of the aerosol for a period of approximately six minutes, which corresponds to the typical time spent smoking a traditional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have a capacity sufficient to permit a specified number of puffs or individual activations of the heater assembly.

The aerosol generating device may include a housing. The body may be oblong. The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of such materials, or thermoplastic materials suitable for use in the food or pharmaceutical industries, such as polypropylene, polyetheretherketone (PEEK) and polyethylene. The material is preferably light and non-fragile.

The aerosol generating system may be a hand held aerosol generating system. The aerosol generating system may be a hand-held aerosol generating system configured to allow a user to draw from a mouthpiece to draw the aerosol through an opening at the mouthpiece end. The aerosol generating system can be of a size comparable to a traditional cigar or cigarette. The aerosol generating system may have an overall length of from about 30 mm to about 150 mm. The aerosol generating system may have an outer diameter of from about 5 mm to about 30 mm.

According to one example of the present invention, there is provided a method for manufacturing a heating element for an aerosol generating system. The method may include providing a plurality of first threads. The plurality of first filaments may be configured to heat the liquid substrate to form an aerosol. The method may include providing a plurality of second threads. The plurality of second filaments may be configured to carry a liquid aerosol-forming substrate along at least a portion of their length to distribute the liquid aerosol-forming substrate along at least a portion of the heating element.

According to one example of the present invention, there is provided a method of making a heating element for an aerosol generating system, the method comprising: providing a plurality of first filaments configured to heat a liquid aerosol generating substrate; and providing a plurality of second filaments configured to carry a liquid aerosol-forming substrate along at least a portion of their length to distribute the liquid aerosol-forming substrate along at least a portion of the heating element.

As an advantage, the plurality of second threads are configured to carry a liquid aerosol-forming substrate to and through the first threads. Thus, the second filaments serve as wicks, but within the main body of the heating element, and help wet the heating element with the liquid aerosol-forming substrate by increasing the area of the first filaments that is in contact with the liquid aerosol-forming substrate. The second filaments assist in distributing the aerosol-forming substrate over the heating element to achieve better wetting of the first filaments and increase the evaporation area. The heating element of the present invention helps to provide a constant area of the heating element that is wetted during each use of the aerosol generating system, and thus helps to generate a constant amount of aerosol over a number of successive uses and for different aerosol generating systems of the same type. The second threads may also help improve the incorporation of the heating element into a porous material or other form of transfer material used to transfer the aerosol-forming liquid substrate to the heating element. In addition, the second filaments help to increase the contact area between the heating element and the transfer material.

As an advantage, by including multiple second filaments in the heating element, consistency of aerosol delivery can be improved and inter-item variation reduced. The heating element can also be manufactured in a simple and uniform manner using mass production techniques.

In one example, the heating element may comprise a mesh. The method may include alternately arranging a first thread and a second thread in a first direction and arranging the first thread in a second direction. Alternatively, the method may include alternately positioning the first thread and the second thread in a second direction.

In another example, the heating element may comprise a mesh. The method may include arranging a plurality of first threads in a first direction and arranging a plurality of second threads in a second direction.

The features described in relation to one of the above examples can be equally applied to other examples according to the present invention.

The present invention is defined by the claims. However, the following is a non-exhaustive list of non-limiting examples. Any one or more features of these examples can be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1: Heating element for an aerosol generating system, the heating element comprising: a first filament configured to heat a liquid aerosol-generating substrate; and a second filament configured to carry a liquid aerosol-forming substrate to wet at least a portion of the heating element with the liquid aerosol-forming substrate.

Example Ex2: A heating element according to Example Ex1, wherein the heating element includes a plurality of first filaments and a plurality of second filaments.

Example Ex3: Heating element according to example Ex1 or Ex 2, wherein the first thread(s) is/are formed from an electrically conductive material.

Example Ex4: Heating element according to any one of Examples Ex1 to Ex 3, wherein the first filament(s) is/are formed of a metallic material.

Example Ex5: Heating element according to any previous example, wherein the second thread(s) is/are hydrophilic.

Example Ex6: Heating element according to any previous example, wherein the second filament(s) is/are formed of a non-metallic material.

Example Ex7: A heating element according to Example Ex2, wherein a plurality of first filaments is formed of a magnetic metal material and a plurality of second filaments is formed of a non-metallic hydrophilic material, and wherein the heating element further comprises a plurality of third filaments which are formed of a non-magnetic metal material.

Example Ex8: The heating element according to any one of Examples Ex2 to Ex7, wherein the plurality of first filaments and the plurality of second filaments extend in the same direction and are intertwined.

Example Ex9: A heating element according to any one of Examples Ex2 to Ex7, wherein the plurality of first filaments are arranged to form a mesh in which a portion of the plurality of first filaments is disposed in a first direction and another portion of the plurality of first filaments is disposed in a second direction transverse to the first direction direction, and wherein individual threads of the plurality of second threads are located between at least some of the first threads in at least one of the first or second directions.

Example Ex10: Heating element according to Example Ex9, wherein a plurality of second filaments can be arranged in both the first and second directions.

Example Ex11: A heating element according to Example Ex9 or Ex10, wherein a plurality of second filaments may be disposed between a plurality of first filaments such that each space between adjacent filaments of the plurality of first filaments contains a second filament.

Example Ex12: A heating element according to any one of Examples Ex2 to Ex7, wherein the heating element is arranged to form a grid, the plurality of first filaments being disposed in a first direction, and the plurality of second filaments being disposed in a second direction, the second direction being transverse to the first direction direction.

Example Ex13: A heating element according to any one of Examples Ex9 to Ex12, wherein the heating element comprises an interlocking mesh.

Example Ex14: A heating element according to any previous example, wherein each of the first filaments has an average diameter of 10 to 80 microns, preferably 10 to 50 microns, and more preferably approximately 25 microns.

Example Ex15: Heating element according to any previous example, wherein each of the second filaments has an average diameter of 10 to 80 microns, preferably 10 to 50 microns, and more preferably approximately 25 microns.

Example Ex16: Heating element according to any previous example, wherein the heating element is substantially flat.

Example Ex17: A heater assembly for an aerosol generating system, the heater assembly comprising a heating element according to any of the previous examples and a transfer material for transferring a liquid aerosol-generating substrate to the heating element.

Example Ex18: The heater assembly according to Example Ex17, with portions of some of the plurality of second filaments included in the transfer material.

Example Ex19: A heater assembly according to Example Ex17 or Ex18, further comprising at least two electrical contacts for supplying electrical power to the heating element, each of the electrical contacts being connected to at least one of the plurality of first filaments.

Example Ex20: A cartridge for an aerosol generating system, the cartridge comprising a heater assembly according to any one of Examples Ex17 to Ex19 and a liquid storage portion for holding a liquid aerosol generating substrate.

Example Ex21: An aerosol generating system comprising: a cartridge according to Example Ex20; and an aerosol generating device, wherein the cartridge is releasably coupled to the aerosol generating device, the aerosol generating device including a power source for supplying electrical power to the heating element.

Example Ex22: A method of making a heating element for an aerosol generating system, the method comprising: providing a plurality of first filaments configured to heat a liquid aerosol generating substrate; and providing a plurality of second filaments configured to carry a liquid aerosol-forming substrate along at least a portion of their length to distribute the liquid aerosol-forming substrate along at least a portion of the heating element.

Example Ex23: The method according to Example Ex22, wherein the heating element comprises a mesh, and the method further includes alternately arranging the first filament and the second filament in a first direction and arranging the first filament in a second direction.

Example Ex24: A method according to Example Ex22 or Ex23, wherein the method further includes alternately arranging the first thread and the second thread in the second direction.

Example Ex25: The method according to Example Ex22, wherein the heating element comprises a mesh and the method includes arranging a plurality of first filaments in a first direction and arranging a plurality of second filaments in a second direction.

In the following, examples will be further described with reference to the figures, in which:

in fig. 1 is a schematic top view of a heating element according to one example of the present invention.

In fig. 2 is a schematic top view of a heating element according to another example of the present invention.

In fig. 3A is a schematic representation of one filament arrangement of the heating element of FIG. 2.

In fig. 3B is a schematic representation of another filament arrangement of the heating element of FIG. 2.

In fig. 4 is a perspective view of a heater assembly according to one example of the present invention.

In fig. 5 is a top view of a heater assembly according to another example of the present invention.

In fig. 6A is an enlarged cross-sectional view through a portion of a heater assembly in accordance with one example of the present invention.

In fig. 6B is an enlarged cross-sectional view through a portion of a heater assembly according to another example of the present invention.

In fig. 7 is a schematic diagram of an example of an aerosol generating system comprising a cartridge and an aerosol generating device according to one example of the present invention.

In fig. 8A is a schematic illustration of an apparatus used to measure the capillary properties of a heating element.

In fig. 8B is a graph depicting the absorption of aerosol-forming liquid substrate as a function of time for three different heating element samples.

With reference to FIG. 1 is a schematic top view of a heating element 1. The heating element 1 is a hybrid heating element comprising a plurality of first filaments 2 that are configured to heat an aerosol-forming liquid substrate (not shown) and a plurality of second filaments 4 that are configured to transfer a liquid aerosol-forming substrate for wetting at least a portion of the heating element 1 with the liquid aerosol-forming substrate. A plurality of first threads 2 and a plurality of second threads 4 extend in the same direction and are intertwined. In other words, each of the second threads 4 is located between adjacent threads of a plurality of first threads 2. The plurality of first threads 2 and the plurality of second threads 4 are held in place by attaching them to an underlying substrate or transfer material (not shown).

The plurality of first threads 2 are electrically conductive and made of stainless steel wire. The plurality of second threads 4 are made of glass fiber threads which are hydrophilic. The aerosol-forming liquid substrate is carried or drawn along the length of the plurality of second filaments 4 by capillary action between the fibers of the glass fiber filaments. This, in turn, helps to pull or carry the liquid aerosol-forming substrate along the plurality of first threads 2. In addition, the spaces 6 between the first 2 and second 4 threads serve as capillary channels that help to carry and pull the liquid aerosol-forming substrate, along the plurality of first filaments 2. Thus, the plurality of second filaments 4 help to continuously wet the heating element 1 by distributing the aerosol-forming liquid substrate within or across the heating element 1.

In use, the plurality of first filaments 2 of the heating element 1 may be inductively or resistively heated. The heat generated by the plurality of first filaments 2 evaporates the liquid substrate, forming an aerosol, which is released from the heating element 1 in the spaces 6 between the first 2 and second 4 filaments. The glass fiber strands of the plurality of second strands 4 are capable of withstanding the temperatures of the plurality of first strands 2 during heating.

In fig. 2 is a schematic top view of another example of a heating element 10. The heating element 10 includes an interlocking mesh 12 having a plurality of first filaments and a plurality of second filaments having pores or cells 14. FIG. 3A and 3B show different arrangements of multiple first and second filaments of the heating element 10. In each of FIGS. 3A and 3B show only a portion of the heating element 10, which has been enlarged for clarity. Similar to heating element 1 in FIG. 1, a plurality of first threads is made of electrically conductive stainless steel wire and is configured to heat a liquid substrate forming an aerosol (not shown). The plurality of second filaments 14b are made of hydrophilic fiberglass filaments and are configured to carry a liquid aerosol-forming substrate to wet at least a portion of the heating element 1 with the liquid aerosol-forming substrate.

When arranged as in FIG. 3A, a plurality of first filaments 16a, 16b, i.e. heating filaments, are arranged in a mesh configuration. Half of the plurality of first threads 16a is located in a first weave direction, and the other half of the plurality of first threads 16b is located in a second weave direction, which is substantially perpendicular to the first direction. The cells 14 are located between and limited by the plurality of first threads 16a, 16b.

When arranged as shown in FIG. 3A, a plurality of second filaments 18a, 18b, i.e., capillary filaments, are disposed between a plurality of first filaments 16a, 16b in both first and second directions such that each space between adjacent filaments of the plurality of first filaments 16a, 16b contains a second filament 18a , 18b. In other words, the interlocking mesh heating element of FIG. 3A includes alternating first 16a and second 18a threads in a first direction and alternating first 16b and second 18b threads in a second direction. The first and second directions are substantially perpendicular to each other. A plurality of second filaments 18a, 18b intersect in cells 14 between a plurality of first filaments 16a, 16b and occupy at least a portion of the area of each of the cells 14. In this arrangement, the plurality of second filaments 18a, 18b help to carry or draw the aerosol-forming liquid substrate into the pores or cells 14 between and across the plurality of first filaments 16a, 16b, which in turn helps wet the heating element 10.

When arranged as shown in FIG. 3B, the heating element 10 is configured in a mesh configuration. A plurality of first filaments 16, ie heating filaments, are arranged in a first direction, and a plurality of second filaments 18, ie capillary filaments, are disposed in a second direction. The second direction is substantially perpendicular to the first direction. With this arrangement, the plurality of second filaments 18 help to carry or pull the aerosol-forming liquid substrate into the spaces 14 between the plurality of first filaments 16, which helps wet the heating element 10.

It should be noted that FIG. 1, 2, 3A and 3B are schematic and not to scale. For clarity, the figures have been simplified and the size of their elements has been changed. For example, the threads have been enlarged and their aspect ratio changed. In addition, fewer filaments are shown than would be present in an actual heating element.

In fig. 4 is a perspective view of the heater assembly 100 including the mesh heating element 10 of FIG. 2 and transfer material 102. The mesh heating element 10 may have an arrangement of threads or as shown in FIG. 3A, or as shown in FIG. 3B as described above. The transfer material is made of porous ceramic. Any suitable ceramic can be used for the transfer material. The heating element 10 is fixedly attached to the top surface of the transfer material 102. Any suitable fixation method may be used to attach the heating element 10 to the transfer material.

The transfer material 102 is configured to transfer a liquid aerosol-forming substrate (not shown) to the mesh heating element 10. As described above with respect to FIGS. 2, a plurality of pores or cells are defined between the filaments of the mesh heating element 10. During heating, a vaporized aerosol-forming substrate may be released from the heater assembly 100 through the aerosol generating cells.

The heater assembly 100 further includes a pair of electrical contacts 104 for supplying electrical power to the heating mesh element 10. The electrical contacts 104 include a pair of tin pads that are attached directly to the heating mesh element 10 and located on opposite sides of the mesh. Although the electrical contacts cover a portion of the mesh heating element 10, a sufficient portion of the mesh heating element 10 remains exposed so that aerosol generation is not affected.

In fig. 5 is a top view of another example of a heater assembly 200 including a heater mount 202 and an interlocking mesh heating element 204. A rectangular opening 206 is formed at the upper end 202a of the heater mount 202 and extends through the upper end 202a of the heater mount 202 into an interior compartment (not shown). which contains a liquid substrate that forms an aerosol (not shown). The liquid aerosol-forming substrate may pass through the rectangular opening 206 to the mesh heating element 204. A transfer material (not shown) may be positioned in the rectangular opening 206 in contact with the mesh heating element 204 to transfer the liquid aerosol-forming substrate to the heating mesh. element 204. The mesh heating element 204 extends through the rectangular opening 206 and is fixedly attached to the top surface 202a of the heater mount 202 on opposite sides of the heater mount 202. Any suitable fastening method may be used to secure the heating element 204 to the heater mount 202. The heater mount 202 is made of PEEK.

The heater mount 202 is configured to receive an induction coil (not shown) of an aerosol generating device (not shown) so that the mesh heating element 204 can be inductively heated. The mesh heating element 204 includes a plurality of first filaments 204a, which are made of magnetic stainless steel wire such as AISI 430. The plurality of first filaments 204a are inductively heated to heat a liquid substrate to form an aerosol. A plurality of first filaments 204a are disposed in a first direction of the interlocking mesh heating element 204, the first direction of which is aligned with the direction of the applied alternating magnetic field generated by the induction coil. The mesh heating element 204 also includes a plurality of second filaments 204b, which are made of glass fiber filaments. The plurality of second filaments 204b are configured to carry a liquid aerosol-forming substrate to wet at least a portion of the mesh heating element 204 with the liquid aerosol-forming substrate. A plurality of second threads 204b are located in a second direction of the interlocking mesh heating element 204. The second direction is substantially perpendicular to the first direction. The mesh heating element 204 further includes two sets of third filaments 204c, which are made of non-magnetic stainless steel wire, such as AISI 304. The plurality of third filaments 204c are designed not to be subject to induction heating. A plurality of third filaments 204c are also located in a first direction of the interlocking mesh heating element 204 and are placed on both sides of a portion of the mesh heating element 204 formed by the plurality of first filaments 204a.

The mesh heating element 204 is fixedly attached to the heater mount in the portions of the mesh heating element 204 formed by the plurality of third threads 204c. The plurality of third filaments 204c, made of non-magnetic stainless steel wire, are not heated by the induction coil of the aerosol generating device, and thus the portions of the mesh heating element 204 formed by the plurality of third filaments 204c are prevented from becoming significantly heated. This helps reduce heat and thermal stress in areas where the mesh heating element 204 is statically attached to the heater mount 202, which in turn helps reduce damage to the heater mount 202 caused by heating the mesh heating element 204.

In fig. 6A is an enlarged cross-sectional view through a portion of an example heater assembly 300a including the mesh heating element 10 of FIG. 2 and transfer material 302. The mesh heating element 10 has the arrangement of threads as shown in FIG. 3B as described above. In other words, the mesh heating element 10 includes a plurality of first, or heating, threads 16 located in a first (lobar) direction and a plurality of second, or capillary, threads 18, located in a second (transverse) direction, which is substantially perpendicular to the first direction. However, the thread arrangement shown in FIG. 3B or any other suitable thread arrangement. The transfer material is made of porous ceramic. Any suitable ceramic can be used for the transfer material. The heating element 10 is fixedly attached to the top surface 302a of the transfer material 302. Any suitable fixation method may be used to attach the heating element 10 to the transfer material 302.

A plurality of second filaments 18 carry or capillary transfer the liquid aerosol-forming substrate from the transfer material 302 into the spaces 14 between the plurality of first filaments 16 of the mesh heating element 10, as indicated by arrows A in FIG. 6A. This promotes wetting of the mesh heating element 10 and improves contact between the plurality of first filaments 16 and the transfer material 302, which improves the transfer of the aerosol-forming liquid substrate from the transfer material 302 to the plurality of first filaments 16. The plurality of first filaments 16 heats and vaporizes the liquid substrate , and the vaporized aerosol-forming substrate exits the heater assembly 300a through spaces 14 in the mesh heating element 10. The mesh heating element 10 is continuously wetted between uses, which helps produce an improved and more consistent aerosol.

In fig. 6B is an enlarged cross-sectional view through a portion of another example of heater assembly 300b. Location according to Fig. 6B is similar to the arrangement in FIG. 6A, except that the mesh heating element 10 is included or embedded in the ceramic transfer material 302 such that the top surface 302a of the transfer material 302 is now in contact with a plurality of first filaments 16, i.e., heating filaments. Portions of the plurality of second threads 18, ie capillary threads, which are below the plurality of first threads 16, are embedded within the ceramic. The wave-like shape of the plurality of second filaments 18 assists in incorporating the mesh heating element 10 into the transfer material since it provides portions that can be embedded in the ceramic. Portions of the plurality of second threads 18 below the plurality of first threads 16 may be embedded in the pores of the porous ceramic transfer material, or the transfer material may be provided with recesses or recesses to receive portions of the plurality of second threads 16. Alternatively, the transfer material may be applied directly onto the underside of the mesh heating element 10 through some type of physical deposition, vapor deposition, or electrodeposition process.

In fig. 7 is a schematic representation of an example of an aerosol generating system. The aerosol generating system includes two main components, a cartridge 400 and a main body or aerosol generating device 500. The connecting end 415 of the cartridge 400 is removably connected to the corresponding connecting end 505 of the aerosol generating device 500. Both the connecting end 415 of the cartridge 400 and the connecting end 505 of the aerosol generating device 500 have electrical contacts or connections (not shown) that are compatible to provide an electrical connection between the cartridge 400 and the aerosol generating device 500. The aerosol generating device 500 includes a power source in the form of a battery 510, which in this example is a rechargeable lithium-ion battery, and a control circuit 520. The aerosol generating system is portable and comparable in size to a traditional cigar or cigarette. The mouthpiece 425 is located at the end of the cartridge 400 opposite the connecting end 415.

The cartridge 400 includes a housing 405 containing the heater assembly 100 of FIG. 4 and a liquid storage compartment or portion having a first storage portion 430 and a second storage portion 435. The liquid storage compartment holds the liquid substrate to form an aerosol. Although in FIG. 7, not shown, the first storage portion 430 of the liquid storage compartment is connected to the second storage portion 435 of the liquid storage compartment so that the liquid contained in the first storage portion 430 is allowed to flow into the second storage portion 435. The heater assembly 100 receives liquid from the second liquid storage compartment storage portion 435. At least a portion of the ceramic transfer material of the heater assembly 100 extends into the second storage portion 435 of the liquid storage compartment for contact with the aerosol-forming liquid substrate therein.

An air flow passage 440, 445 extends through the cartridge 400 from an air inlet 450 formed on the side of the housing 405, past the mesh heating element of the heater assembly 100, and from the heater assembly 100 to a mouthpiece hole 410 formed in the housing 405 at the end cartridge 400 opposite the connecting end 415.

The components of the cartridge 400 are arranged such that the first liquid storage compartment storage portion 430 is located between the heater assembly 100 and the mouthpiece hole 410, and the second liquid storage compartment storage portion 435 is located on the opposite side of the heater assembly 100 from the mouthpiece hole 410 In other words, the heater assembly 100 lies between the two liquid storage compartment portions 430, 435 and receives the liquid from the second storage portion 435. The first liquid storage compartment storage portion 430 is closer to the mouthpiece hole 410 than the second liquid storage compartment storage portion 435. An air flow passage 440, 445 extends past the heating mesh element of the heater assembly 100 and between the first 430 and second 435 portions of the liquid storage compartment.

The aerosol generating system is configured such that the user is able to puff or draw through the mouthpiece 425 of the cartridge to draw the aerosol into his mouth through the mouthpiece opening 410. In operation, when the user puffs through the mouthpiece 425, air is drawn through the passage 440, 445 to flow air from air inlet 450 past heater assembly 100 to mouthpiece 410. Control circuitry 520 controls the supply of power from battery 510 to cartridge 400 when the system is activated. This, in turn, controls the amount and properties of steam produced by the heater assembly 100. The control circuit 520 may include an air flow sensor (not shown), and the control circuit 520 may provide power to the heater assembly 100 when the air flow sensor detects user tightening. This type of control arrangement is traditional in aerosol-generating systems such as inhalers and e-cigarettes. When a user draws from the tip opening 410 of the cartridge 400, the heater assembly 100 is activated and generates vapor that is entrained in the air flow passing through the air flow passage 440. The vapor is cooled in the air flow in passage 445 to form an aerosol, which is then drawn into the user's mouth through mouthpiece opening 410.

In operation, the mouthpiece opening 410 is typically the highest point of the system. The design of the cartridge 400, and in particular the positioning of the heater assembly 100 between the first and second liquid storage compartment storage portions 430, 435, provides an advantage in that gravity is used to ensure delivery of the liquid substrate to the heater assembly 100 even when the liquid storage compartment is emptied, but this prevents excess liquid supply to the heater assembly 100, which would cause liquid to leak into the air flow passage 440.

In fig. 8A shows a schematic representation of an apparatus 600 used to measure the capillary properties of mesh heating element 602. A rectangular sample of mesh heating element 602 measuring 10 mm by 5 mm is prepared. A sample of mesh heating element 602 is suspended vertically by one of its narrow edges from a scale 604, which is capable of accurately measuring the weight of objects weighing up to 0.0001 grams. The scale can be connected to a computer (not shown), which records the weight measurement over a period of time. A container 606 containing an amount of liquid aerosol-forming substrate 608 is positioned beneath a sample heating mesh element 602. The heating mesh 602 is lowered until the lower horizontal narrow edge 602a of the sample mesh heating element 602 comes into contact with the liquid substrate 608, forming an aerosol in container 606. The amount of liquid absorbed by the mesh heating element 602 is then recorded as a function of the time elapsed since capillary transfer began, i.e., from the time a sample of mesh heating element 602 came into contact with the liquid substrate , forming an aerosol. The absorption of liquid by the sample mesh heating element 602 occurs due to the vertical wetting of the heating element 602 by the liquid substrate, forming an aerosol.

In fig. 8B shows a graph of aerosol-forming liquid substrate absorption in grams versus elapsed time in milliseconds for three different mesh heating element samples. The samples have the materials and dimensions shown in Table 1 below.

Sample Materials and sizes Sample 1 AISI 430 stainless steel wire, wire diameter 63 microns, mesh size 80 microns Sample 2 AISI 312 stainless steel wire, wire diameter 25 microns, mesh size 100 microns Sample 3 AISI 312 stainless steel wire, wire diameter 25 microns, mesh size 100 microns, glass fiber threads added in one direction of the mesh (in Fig. 8A they are in the vertical direction), the width of the thread is approximately equal to the mesh size, i.e. . approximately 100 microns, the thickness of the thread is approximately equal to the diameter of the wire, i.e. approximately 25 microns

Table 1

As can be seen from Table 1, samples 1 and 2 are made of the same material. However, sample 3 is a hybrid mesh and contains both stainless steel wire as the first threads and fiberglass threads as the second threads.

The graph in Fig. 8B shows the relative efficiency of samples 1-3. As can be seen from the graph, the hybrid mesh according to sample 3 shows significantly higher efficiency compared to samples 1 and 2 in terms of liquid absorption rate and amount of liquid absorbed. Sample 3 has a higher absorption rate of the aerosol-forming liquid substrate compared to Samples 1 and 2. This means that the mesh heating element of Sample 3 will rewet the previous puff faster than the other two samples. In addition, after 500 milliseconds, the amount of liquid absorbed by the hybrid network according to sample 3 is approximately twice that of sample 2, the closest competitor, indicating that the capillarity and wetting properties of sample 3 are better and that fast capillary transfer and wetting. Thus, from FIG. 8B, it can be concluded that the provision of a hybrid network improves the capillarity and wetting properties. This helps achieve more consistent aerosol generation between successive puffs and between aerosol generating devices of the same type.

Claims (19)

1. A heating element for an aerosol generating system, the heating element comprising a plurality of first filaments and a plurality of second filaments, the plurality of first filaments being configured to heat a liquid aerosol-generating substrate; wherein the plurality of second filaments are configured to carry a liquid aerosol-forming substrate to wet at least a portion of the heating element with the liquid aerosol-forming substrate; And wherein the heating element is arranged so as to form a grid, with a plurality of first filaments located in a first direction, and a plurality of second filaments located in a second direction, and wherein the second direction is transverse to the first direction. 2. The heating element according to claim 1, characterized in that the plurality of first filaments is formed from an electrically conductive material. 3. A heating element according to any of the previous paragraphs, characterized in that the plurality of second filaments are hydrophilic. 4. The heating element according to any of the previous paragraphs, characterized in that the plurality of second filaments is formed from a non-metallic material. 5. The heating element according to claim 1, wherein the plurality of first filaments is formed of a magnetic metal material, and the plurality of second filaments is formed of a non-metallic hydrophilic material, and the heating element further comprises a plurality of third filaments, which are formed of a non-magnetic metal material. 6. Heating element according to any previous paragraph, characterized in that the heating element contains an interwoven mesh. 7. A heater assembly for an aerosol generating system, the heater assembly comprising a heating element as defined in any one of the preceding claims and a transfer material for transferring the aerosol generating liquid substrate to the heating element. 8. The heater assembly of claim 7, wherein portions of some of the plurality of second filaments are included in the transfer material. 9. The heater assembly according to claim 7 or 8, characterized in that it further comprises at least two electrical contacts for supplying power to the heating element, each of the electrical contacts being connected to at least one of the plurality of first filaments. 10. A cartridge for an aerosol generating system, wherein the cartridge contains a heater assembly according to any one of claims. 7-9 and a liquid storage portion for holding the liquid substrate forming an aerosol. 11. An aerosol generating system containing: cartridge according to claim 10; And an aerosol generating device, wherein the cartridge is removably connected to the aerosol generating device, wherein the aerosol generating device comprises a power source for supplying electrical power to the heating element. 12. A method for manufacturing a heating element for an aerosol generating system, the method comprising the steps of: provide a plurality of first filaments configured to heat a liquid substrate forming an aerosol; providing a plurality of second filaments configured to carry a liquid aerosol-forming substrate along at least a portion of their length to distribute the liquid aerosol-forming substrate along at least a portion of the heating element; And the heating element is positioned such that it forms a grid, with a plurality of first filaments located in a first direction, and a plurality of second filaments located in a second direction, the second direction being transverse to the first direction.

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