Inductively coupled heater

Abstract

To provide an aerosol-generation device.SOLUTION: The invention relates to an aerosol-generating device comprising a main body (10) and a mouthpiece (20). The main body comprises a primary coil (12) and a power supply (14). The mouthpiece comprises a secondary coil (22), a heating chamber (26) for receiving an aerosol-forming substrate (28), and a resistive heating element (24) arranged at least partly around the heating chamber. The mouthpiece is detachably connectable to the main body. The aerosol generating device is configured such that the primary coil and the secondary coil are inductively coupled when the mouthpiece is connected to the main body. The invention further relates to an aerosol-generating system comprising the aerosol-generating device and an aerosol-generating article, and to a method for forming an aerosol in an aerosol-generating device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an aerosol generating device. The present disclosure further relates to an aerosol generating system comprising an aerosol generating device and an aerosol-generating article. The present disclosure further relates to a method of forming an aerosol in an aerosol generating device. [Background technology]

[0002] It is known to provide aerosol-generating devices for generating inhalable vapors. Such devices may heat an aerosol-forming substrate contained in the aerosol-generating article without combustion. The aerosol-generating article may have a shape suitable for insertion into the heating chamber of the aerosol-generating device. For example, the aerosol-generating article may have a rod shape. A heating element may be disposed in or around the heating chamber to heat the aerosol-forming substrate after the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.

[0003] It is known to provide a modular aerosol generating device comprising two or more sub-units removably mounted relative to one another, and electrical connectors may be provided for electrically connecting a power source in one sub-unit to electrical consumers in another sub-unit in the assembled state.

[0004] Electrical connectors often have sensible connection surfaces, e.g., metal surfaces that are brought into intimate physical contact to establish an electrical connection. Processes such as surface oxidation or the deposition of liquid or solid particles can lead to a reduction in the conductance of the metal surface, which can adversely affect the electrical connection.

[0005] These effects can be particularly severe in aerosol-generating systems in which the aerosol-forming substrate is heated but not combusted. Heat and moisture generated during aerosolization can promote surface oxidation of the connecting surface. Particles of the aerosol-forming substrate can be inadvertently deposited on the connecting surface.

[0006] Electrical connectors often include a material transition between a conductive and a non-conductive material (e.g., a metal surface adjacent to a plastic surface). The material transition may involve gaps or surface creases. Moisture may inadvertently enter the interior of the device through the gaps. Particulate matter may inadvertently deposit in surface creases.

[0007] Electrical connectors often require precise alignment of opposing conductive surfaces of the components to be connected. Summary of the Invention [Problem to be solved by the invention]

[0008] It would be desirable to provide a modular aerosol generator having durable electrical connectors. It would be desirable to provide a modular aerosol generator having stable, functioning electrical connections between subunits. It would be desirable to provide a modular aerosol generator that allows for attachment and detachment of subunits in an operationally simple manner. It would be desirable to provide a modular aerosol generator that is easy to clean. [Means for solving the problem]

[0009] According to one embodiment of the present invention, there is provided an aerosol generating device. The aerosol generating device may comprise a main body comprising a primary coil and a power source. The aerosol generating device may comprise a mouthpiece comprising a secondary coil and a heating element (preferably a resistive heating element). The mouthpiece may be removably connectable to the main body. The aerosol generating device may be configured such that when the mouthpiece is connected to the main body, the primary coil and the secondary coil are inductively coupled.

[0010] According to one embodiment of the present invention, there is provided an aerosol generating device comprising a main body. The main body comprises a primary coil and a power source. The aerosol generating device further comprises a mouthpiece. The mouthpiece comprises a secondary coil and a resistive heating element. The mouthpiece is removably connectable to the main body. The aerosol generating device is configured such that when the mouthpiece is connected to the main body, the primary coil and the secondary coil are inductively coupled.

[0011] Inductive coupling between the primary coil in the main body and the secondary coil in the mouthpiece may avoid the need for an electrical connector with a sensible connection surface (e.g., a metal surface) to connect the mouthpiece to the main body. Inductive coupling between the primary coil in the main body and the secondary coil in the mouthpiece may provide a modular aerosol generator with a durable electrical connector. A modular aerosol generator may make it possible to provide a stable and functional electrical connection between subunits. For example, the primary coil may be embedded in a plastic housing of the main body, and the secondary coil may be embedded in a plastic housing of the mouthpiece, so that open metal connector sides are not required.

[0012] The need for cleaning open metal connector sides may be avoided by inductive coupling. The modular aerosol generator may be easy to clean. Inductive coupling of the modular aerosol generator may allow attachment and detachment of sub-units in an operationally simple manner. For example, precise alignment of the respective metal electrical connectors of the main body and mouthpiece may not be required.

[0013] Power may be transferred inductively from the primary coil to the secondary coil, and therefore the primary coil may be the active coil and the secondary coil may be the passive coil of the inductive system.

[0014] Power transfer by inductive coupling is based on the physical principle of mutual inductance. The system of active and passive helical coils can essentially be considered as two air-core solenoids. The magnetic flux induced in the active coil induces an equal and opposite electromotive force (emf) "ε" in the passive coil.

[0015] In one embodiment, the active coil completely coaxially surrounds the passive coil, and both coils have the same number of turns and the same length perpendicular to the diameter of the turns. If we further assume that there is no flux leakage and that the two coils are perfectly magnetically coupled, the flux of the active coil is JPEG2025175060000002.jpg7170 is the flux of the passive coil JPEG2025175060000003.jpg7170, which can be estimated as follows:

number

[0016] The effective coil magnetic field strength "B" is given by equation (2).

number

[0017] JPEG2025175060000006.jpg6170 is the magnetic constant, "I" is the current, "N" is the number of turns in the coil, and "l" is the length of the coil. Then the effective coil flux is JPEG2025175060000007.jpg7170. "A" is the cross-sectional area of ​​the coil in the direction perpendicular to its length. Assuming a circular cross section and a radius of turns R,

number

[0018] The mutual inductance "M" is the link inductance in the two coils. As a result of the perfect magnetic linkage, the inductance passing through the passive coil can then be written as:

number

[0019] The induced emf "ε" in the passive coil can then be simply stated to be equal to:

number

[0020] Obviously, this is an ideal model, there may be losses in the system and the induced emf will be less than that calculated. The losses are calculated using the linear efficiency coefficient JPEG2025175060000011.jpg6170. Thus, the final equation for the voltage induced in the passive coil can be written by combining equations 2, 3, 4, and 5:

number

[0021] Exemplary dimensions for the two coils are a 5 mm turn radius "R" for the active coil, a 4 mm turn radius for the passive coil coaxially disposed within the active coil, 15 turns "N" for each coil, and a 10 mm length "l" for both coils. Using these dimensions and a linear efficiency factor of 0.85, JPEG2025175060000013.jpg6170 Further assuming, we can calculate the relationship between the emf in the passive coil and the rate of change of the active current.

number

[0022] Using equation (7), it is now possible to look up the circuit requirements of the system.

[0023] It is clear from the digits in "M" that a high frequency is required to induce an emf capable of powering a heater, with a typical value of, say, about 4 watts. For a typical peak-to-peak current in the active circuit, say, about 6 amps, it is possible to construct the governing equations for the circuit and plot the power transfer in the passive side against the frequency of the system. The leakage current in the passive side JPEG2025175060000015.jpg6170 is the coupling constant, which is the component of the passive inductance that is not linked to the active side It can be calculated using JPEG2025175060000016.jpg6170.

number

[0024] The device will need to compensate for the leakage inductance loss on the passive side. JPEG2025175060000018.jpg6160 is 6·10 -7With a simple reference circuit on the passive side with a passive coil and load resistor, the losses in the passive side of the circuit are approximately 50% at a desired operating power of 4 watts.

number

[0025] Parallel compensation inductor across the load If a 200 nanohenry inductor is introduced, it can be calibrated to offset the effects of leakage inductance. Adding a 200 nanohenry inductor results in a passive coil with approximately 96% efficiency at a 4 watt operating point. A simple circuit operating at 20 kHz and a compensated circuit at 57 kHz require a higher system frequency to reach the same transferred power. Therefore, it may be desirable to build a device with a 200 nanohenry compensation inductor and operate it at a frequency of 57 kHz.

[0026] The primary coil may be wired to a power source. The secondary coil may be wired to a resistance heating element. The primary coil and power source may form part of a primary wired circuit housed within the main body. The secondary coil and resistance heating element may form part of a secondary wired circuit housed within the mouthpiece. Power may be transferred inductively from the primary wired circuit to the secondary wired circuit.

[0027] In some embodiments, only the main body comprises the power source, in other words, in some embodiments, the mouthpiece does not comprise the power source.

[0028] In some embodiments, there is no wired connection between the main body and the mouthpiece, in other words, in some embodiments, the only electrical connection between the main body and the mouthpiece is established via inductive coupling of the primary and secondary coils.

[0029] The aerosol generating device may be configured such that power transferred from the primary coil to the secondary coil via inductive coupling is used to heat the resistive heating element.

[0030] The aerosol generating device may be configured such that the power used to heat the resistive heating element is supplied to the resistive heating element from the secondary coil by a wired connection.

[0031] The aerosol generating device preferably includes a power supply configured to provide power to the heating element. The power supply preferably includes a power source. The power source is preferably a battery, such as a 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. For example, the power supply may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, or a multiple of six minutes. In another example, the power supply may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heater assembly.

[0032] The power supply may comprise control electronics. The control electronics may comprise a microcontroller. Preferably, the microcontroller is a programmable microcontroller. The electrical circuit may comprise further electronic components. The electrical circuit may be configured to regulate the supply of power to the primary coil. Power may be supplied to the primary coil continuously after activation of the system, or may be supplied intermittently (e.g., with each puff). Power may be supplied to the primary coil in the form of current pulses.

[0033] The aerosol generator may be configured to supply alternating current (AC) to the primary coil.

[0034] The control electronics may include a DC / AC converter for converting direct current (DC) provided by the power supply into AC to be supplied to the primary coil. The control electronics may include a DC / AC converter including two transistors in a half-bridge configuration. The control electronics may include a DC / AC converter including a full-bridge configuration with four transistors operating in pairs. The full-bridge configuration may advantageously allow for stronger amplification of the power entering the DC / AC converter from the power supply. This may allow for the use of smaller batteries with lower voltages. The DC / AC converter may include an LC filter.

[0035] The aerosol generation may comprise one or both of a half-bridge driver and a half-bridge. The aerosol generation may comprise an LC filter. The aerosol generation may comprise a half-bridge driver and a half-bridge and an LC filter.

[0036] The aerosol generating device may be configured to induce an alternating current in the secondary coil.

[0037] The aerosol generator may be configured to supply AC induced in the secondary coil to the resistive heating element.

[0038] The mouthpiece may include a rectifier disposed in electrical connection between the secondary coil and the resistive heating element to supply direct current to the resistive heating element, the rectifier being connected in series between the secondary coil and the resistive heating element.

[0039] The primary coil and secondary coil may be made of the same material. The primary coil and secondary coil may be made of different materials. Suitable materials for one or both of the primary coil and secondary coil may be metals and alloys commonly known to those skilled in the art to be used for inductor coils. Exemplary materials are copper or steel.

[0040] The thickness of the coiled wire of the primary coil and the secondary coil may be the same or different, and may be 0.05 mm to 3 mm, preferably 0.1 mm to 1 mm.

[0041] The primary coil and the secondary coil may be helical coils. One or both of the primary coil and the secondary coil may have multiple turns. Either one of the primary coil and the secondary coil may have 5 to 25 turns, preferably 10 to 20 turns, more preferably 13 to 17 turns, and most preferably 15 turns. The primary coil and the secondary coil may have different numbers of turns. In some embodiments, the number of turns of the primary coil differs from the number of turns of the secondary coil by less than 5 turns, or less than 4 turns, or less than 3 turns, or less than 2 turns. The primary coil and the secondary coil may have the same number of turns. The primary coil and the secondary coil may have the same number of turns, or may have 5 to 25 turns, preferably 10 to 20 turns, more preferably 13 to 17 turns, and most preferably 15 turns.

[0042] Either the primary coil or the secondary coil may have a length perpendicular to the winding diameter of 1 to 30 mm, preferably 5 to 20 mm, more preferably 8 to 12 mm, and most preferably about 10 mm. The primary coil and the secondary coil may have different lengths. The primary coil and the secondary coil may have the same length perpendicular to the winding diameter. The primary coil and the secondary coil may have the same length perpendicular to the winding diameter, and the length may be 1 to 30 mm, preferably 5 to 20 mm, more preferably 8 to 12 mm, and most preferably about 10 mm.

[0043] Either the primary coil or the secondary coil may have a winding diameter of 1 to 30 mm, preferably 5 to 15 mm, and more preferably 8 to 10 mm.

[0044] The primary coil and secondary coil may have different winding diameters. The primary coil may be disposed coaxially around the secondary coil when the mouthpiece is connected to the main body, and the primary coil may have a winding diameter of about 10 millimeters, and the secondary coil may have a winding diameter of about 8 millimeters. In some embodiments, the primary coil is disposed coaxially around the secondary coil when the mouthpiece is connected to the main body, and the primary coil has a winding diameter of about 10 millimeters and the secondary coil has a winding diameter of about 8 millimeters, and the primary coil and secondary coil each have 15 turns and each have a length perpendicular to the winding diameter of about 10 millimeters.

[0045] The secondary coil may be disposed coaxially around the primary coil when the mouthpiece is connected to the main body, and the secondary coil may have a winding diameter of about 10 millimeters, and the primary coil may have a winding diameter of about 8 millimeters. In some embodiments, the secondary coil is disposed coaxially around the primary coil when the mouthpiece is connected to the main body, the secondary coil has a winding diameter of about 10 millimeters, and the primary coil has a winding diameter of about 8 millimeters, and the primary and secondary coils each have 15 turns and each have a length perpendicular to the winding diameter of about 10 millimeters.

[0046] The aerosol generating device may be configured to operate the primary coil with an alternating current at an operating frequency between 1 kHz and 50 kHz, preferably between 10 kHz and 30 kHz, more preferably between 15 kHz and 25 kHz, and most preferably around 20 kHz.

[0047] The aerosol generating device may include a parallel compensation inductor. The compensation inductor may be calibrated to offset the effects of leakage inductance. This may advantageously help to compensate for leakage inductance losses in the passive side. The compensation inductor may be a 10-5000 nanohenry inductor, preferably a 100-300 nanohenry inductor, and more preferably a 200 nanohenry inductor.

[0048] The aerosol generating device may include a 200 nanohenry compensation inductor and may be configured to operate the primary coil with alternating current using an operating frequency between 1 kHz and 100 kHz, preferably between 47 kHz and 67 kHz, more preferably between 55 kHz and 60 kHz, and most preferably about 57 kHz.

[0049] The power supply may provide about 6 amps peak-to-peak AC, and the aerosol generator may be configured to deliver about 4 watts to the resistive heating element.

[0050] The mouthpiece may include a heating chamber for receiving the aerosol-forming substrate. The resistive heating element may be disposed at least partially around the heating chamber. The primary and secondary coils may be disposed near a distal end of the heating chamber relative to a longitudinal axis of the device. The primary and secondary coils may be disposed at a distal end of the heating chamber relative to a longitudinal axis of the device.

[0051] The primary coil and the secondary coil may be helical coils. The primary coil and the secondary coil may be arranged coaxially when the mouthpiece is connected to the main body. This allows one of the primary coil and the secondary coil to be inserted into the other coil at any rotational position relative to the insertion axis when the main unit is attached to the mouthpiece. This may also allow for easy attachment and detachment of the sub-units.

[0052] The primary coil and secondary coil may be coaxially disposed about a central longitudinal axis of the device when the mouthpiece is connected to the main body. The primary coil may be coaxially disposed about the secondary coil when the mouthpiece is connected to the main body. The secondary coil may be coaxially disposed about the primary coil when the mouthpiece is connected to the main body.

[0053] The secondary coil may be disposed at least partially around the primary coil when the mouthpiece is connected to the main body. The secondary coil may be disposed entirely around the primary coil when the mouthpiece is connected to the main body. This may improve efficient inductive power transfer from the primary coil to the secondary coil. The secondary coil may be disposed entirely around the primary coil when the mouthpiece is connected to the main body, and both coils may have substantially the same length perpendicular to the winding diameter. This may additionally improve efficient inductive power transfer from the primary coil to the secondary coil.

[0054] The primary coil may be disposed at least partially around the secondary coil when the mouthpiece is connected to the main body. The primary coil may be disposed entirely around the secondary coil when the mouthpiece is connected to the main body. This may improve efficient inductive power transfer from the primary coil to the secondary coil. The primary coil may be disposed entirely around the secondary coil when the mouthpiece is connected to the main body, and both coils may have substantially the same length perpendicular to the winding diameter. This may additionally improve efficient inductive power transfer from the primary coil to the secondary coil.

[0055] The aerosol-generating device may include a temperature sensor. The temperature sensor may be operably coupled to the control electronics of the aerosol-generating device to control the temperature of one or more heating elements. The temperature sensor may be located in any suitable location. For example, the temperature sensor may be configured to monitor the temperature of the aerosol-forming substrate being heated. The sensor may send a signal related to the sensed temperature to the control electronics, which may adjust the power or frequency supplied to the primary coil to achieve the appropriate temperature at the sensor. The temperature sensor may include a thermocouple.

[0056] The temperature sensor may be provided within the main body. The primary coil may be disposed coaxially around the temperature sensor. The temperature sensor may be located near a proximal end of the primary coil relative to the longitudinal axis of the device. The temperature sensor may be located at a proximal end of the primary coil relative to the longitudinal axis of the device.

[0057] In some embodiments, the aerosol-forming substrate is heated to a temperature in the range of about 230°C to about 400°C, preferably about 250°C to about 350°C.

[0058] The aerosol generating device may be a handheld device.

[0059] The aerosol-generating device may be a non-combustion type device, which heats the aerosol-forming substrate without burning it, and which heats the aerosol-forming substrate to a temperature below its combustion temperature.

[0060] The mouthpiece may be removably connectable to the main body by an interference fit connection, a magnetic connection, a threaded connection, or a bayonet lock.

[0061] The present invention further relates to an aerosol-generating system comprising an aerosol-generating device as described herein and an aerosol-forming substrate. The aerosol-forming substrate may be part of an aerosol-generating article. The aerosol-forming substrate, or the aerosol-generating article, may be configured to be at least partially inserted into a heating chamber of the aerosol-generating device.

[0062] The aerosol-forming substrate may be any type of aerosol-forming substrate as described herein. The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosol-forming substrate may comprise one or both of cast leaf and reconstituted tobacco. The aerosol-forming substrate may comprise a gel.

[0063] The present invention further relates to a mouthpiece as described herein for use with a main body as described herein.The present invention further relates to a main body as described herein for use with a mouthpiece as described herein.

[0064] The present invention further relates to a method for forming an aerosol in an aerosol generating device. The method includes generating an alternating current in a primary coil housed within a main body of the aerosol generating device. The method includes inducing a current in a secondary coil inductively coupled to the primary coil and housed within a mouthpiece of the aerosol generating device, with an alternating magnetic field generated by the alternating current in the primary coil, the secondary coil being inductively coupled to the primary coil and housed within a mouthpiece of the aerosol generating device, the mouthpiece being removably connected to the main body. The method includes resistively heating a resistive heating element wired to the secondary coil with the current induced in the secondary coil. The method includes generating an aerosol from an aerosol-forming substrate in thermal contact with the resistive heating element.

[0065] The aerosol generating device may include one or more heating elements. One or both of the primary and secondary coils may function as resistive heating elements in addition to their function as active or passive coils in an induction system. The function of a coil as a resistive heating element may be determined by the coil's specific electrical resistance. For example, a higher specific resistance of the coil may lead to more heat generation within the coil.

[0066] The secondary coil and the resistive heating element provided within the mouthpiece may be one and the same component, and in such an embodiment, the secondary coil is configured to function as a resistive heating element due to its inherent resistivity when power is inductively transferred from the primary coil to the secondary coil.

[0067] A resistive heating element provided within the mouthpiece may be an additional component that is wired to the secondary coil.

[0068] The resistive heating element may be formed from one or more resistive heating tracks. The resistive heating tracks may be provided on a flexible substrate. The resistive heating tracks may be printed on the flexible substrate, for example using a metallic ink. The resistive heating tracks may act as an electrical resistance heater. The flexible substrate may be electrically insulating. The flexible substrate may be a flexible dielectric substrate. The flexible substrate may comprise polyimide. An example of a suitable material is a polyimide film such as Kapton®.

[0069] In all aspects of the present disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, alloys, and composites made of ceramic and metallic materials. Such composites may comprise doped or undoped ceramics. An example of a suitable doped ceramic is doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum platinum, gold, and silver. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, gold-containing, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys. In the composite material, the electrically resistive material may optionally be embedded in, encapsulated in, or coated with the insulating material, or vice versa, depending on the required energy transfer kinetics and external physicochemical properties.

[0070] As noted, in any of the aspects of the present disclosure, the heating element may be part of the aerosol-generating device. The aerosol-generating device may include an internal heating element, an external heating element, or both an internal and an external heating element, where "internal" and "external" refer to the aerosol-forming substrate. The internal heating element may take any suitable form. For example, the internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different conductive portions or an electrically resistive metal tube. Alternatively, the internal heating element may be one or more heated needles or rods that pass through the center of the aerosol-forming substrate. Other alternatives include a heated wire or filament, such as Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire or heating plate. Optionally, the internal heating element may be disposed in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal with a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed into tracks on a suitable insulating material, such as a ceramic material, and then sandwiched in another insulating material, such as glass. A heater formed in this manner may be used to both heat the heating element and monitor its temperature during operation.

[0071] The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foils can be shaped to fit the periphery of the substrate-receiving cavity. Alternatively, the external heating element may take the form of metal grid(s), flexible printed circuit boards, molded circuit components (MIDs), ceramic heaters, flexible carbon fiber heaters, or may be formed using coating techniques such as plasma deposition on a suitably shaped substrate. The external heating element may also be formed using a metal that has a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating material. An external heating element formed in this manner may be used both to heat the external heating element and to monitor the temperature of the external heating element during operation.

[0072] The heating element advantageously heats the aerosol-forming substrate by conduction. The heating element may be in at least partial contact with the substrate or at least partial contact with a carrier on which the substrate is deposited. Alternatively, heat from either an internal or external heating element may be conducted to the substrate by a thermally conductive element.

[0073] In operation, the aerosol-forming substrate may be completely contained within the aerosol-generating device, in which case the user may puff on the mouthpiece of the aerosol-generating device. Alternatively, in operation, the smoking article containing the aerosol-forming substrate may be partially contained within the aerosol-generating device, in which case the user may puff on the smoking article directly.

[0074] The term "aerosol-forming substrate" as used herein refers to a substrate capable of releasing a volatile compound capable of forming an aerosol. The volatile compound may be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases the volatile compound may be released by a chemical reaction or by mechanical stimulation such as ultrasound. The aerosol-forming substrate may be solid or liquid, or may contain both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article.

[0075] The aerosol-forming substrate preferably comprises a plant material and an aerosol former, the plant material preferably being an alkaloid-containing plant material, more preferably being a nicotine-containing plant material, and more preferably being a tobacco-containing material.

[0076] Preferably, the aerosol-forming substrate comprises at least 70 weight percent plant material on a dry weight basis, more preferably at least 90 weight percent plant material. Preferably, the aerosol-forming substrate comprises less than 95 weight percent plant material on a dry weight basis, such as 90-95 weight percent plant material on a dry weight basis.

[0077] The aerosol-forming substrate preferably comprises at least 5 weight percent aerosol formers on a dry weight basis, more preferably at least 10 weight percent aerosol formers. Preferably, the aerosol-forming substrate comprises less than 30 weight percent aerosol formers on a dry weight basis, such as 5 to 30 weight percent aerosol formers on a dry weight basis.

[0078] In some particularly preferred embodiments, the aerosol-forming substrate comprises a plant material and an aerosol former, the substrate having an aerosol former content of 5-30% by weight on a dry weight basis. The plant material is preferably an alkaloid-containing plant material, more preferably a nicotine-containing plant material, and more preferably a tobacco-containing material. Alkaloids are a class of naturally occurring nitrogen-containing organic compounds. Alkaloids are primarily found in plants, but are also found in bacteria, fungi, and animals. Examples of alkaloids include, but are not limited to, caffeine, nicotine, theobromine, atropine, and tubocurarine. A preferred alkaloid is nicotine, which may be found in tobacco.

[0079] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise tobacco, for example, a tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may comprise a homogenized tobacco material, for example, cast leaf tobacco. The aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0080] The term "cast leaf" is used herein to refer to a sheet product made by a casting process based on casting a slurry containing plant particles (e.g., clove particles, or tobacco particles and clove particles in a mixture) and a binder (e.g., guar gum) onto a support surface (such as a belt conveyor), drying the slurry, and removing the dried sheet from the support surface. One example of a casting or cast leaf process is described, for example, in U.S. Pat. No. 5,724,998, for the production of cast leaf tobacco. In the cast leaf process, particulate plant material is mixed with a liquid component (typically water) to form a slurry. Other added components in the slurry may include fibers, binders, and aerosol formers. The particulate plant material may be agglomerated in the presence of a binder. The slurry is cast onto a support surface and dried to form a sheet of homogenized plant material.

[0081] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of emitting a volatile compound that can form an aerosol. The aerosol-generating article may be disposable.

[0082] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating device may interact with one or both of an aerosol-generating article including the aerosol-forming substrate and a cartridge including the aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate release of volatile compounds from the substrate. An electrically operated aerosol-generating device may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.

[0083] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of an aerosol-generating device with an aerosol-generating article. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.

[0084] The aerosol-forming substrate may include a gel. The gel may be tobacco-free. The gel may include nicotine or a tobacco product, or another target compound, for delivery to a user. Nicotine may be included in the gel along with the aerosol former. Additional tobacco or non-tobacco volatile flavor compounds may be included that are released upon heating.

[0085] The gel may be solidified at room temperature. In this context, "solidified" means that the gel has a stable size and shape and does not flow. In this context, room temperature means 25 degrees Celsius. The gel may include an aerosol former as described herein.

[0086] The gel may comprise a gelling agent. Preferably, the gel comprises agar or agarose or sodium alginate. The gel may comprise gellan gum. The gel may comprise a mixture of materials. The gel may comprise water.

[0087] The gel may comprise a thermoreversible gel, meaning that the gel becomes fluid when heated to its melting temperature and becomes a gel again at its gelation temperature. The gelation temperature is preferably above room temperature and above atmospheric pressure. Atmospheric pressure means a pressure of 1 atmosphere. The melting temperature is preferably higher than the gelation temperature. The melting temperature of the gel is preferably above 50°C, or 60°C, or 70°C, and more preferably above 80°C. Melting temperature in this context means the temperature at which the gel is no longer solidified and begins to flow.

[0088] The gel may be provided as a single block or may be provided as multiple gel elements (eg, beads or capsules).

[0089] When agar is used as the gelling agent, the gel preferably contains 0.5 to 5% by weight (more preferably 0.8 to 1% by weight) of agar. The gel may further contain 0.1 to 2% by weight of nicotine. The gel may further contain 30 to 90% by weight (more preferably 70 to 90% by weight) of glycerin. The remainder of the gel may contain water and optional flavoring agents.

[0090] When gellan gum is used as a gelling agent, the gel preferably contains 0.5 to 5% by weight of gellan gum. The gel may further contain 0.1 to 2% by weight of nicotine. The gel may further contain 30 to 99.4% by weight of glycerin. The remainder of the gel may contain water and optional flavoring agents.

[0091] In one embodiment, the gel comprises 2% nicotine, 70% glycerol, 27% water, and 1% agar by weight, while in another embodiment, the gel comprises 65% glycerol, 20% water, 14.3% tobacco, and 0.7% agar by weight.

[0092] As used herein, the term "longitudinal" is used to describe a direction along the major axis of the aerosol generating device, and the term "transverse" is used to describe a direction perpendicular to the longitudinal direction.

[0093] In certain embodiments, the longitudinal axis of the heating chamber is parallel to the longitudinal axis of the aerosol-generating device. For example, the open end of the chamber is located at the proximal end of the aerosol-generating device. In other embodiments, the longitudinal axis of the heating chamber is at an angle to the longitudinal axis of the aerosol-generating device, for example, transverse to the longitudinal axis of the aerosol-generating device. For example, the open end of the heating chamber is located along one side of the aerosol-generating device, such that the aerosol-generating article can be inserted into the heating chamber in a direction perpendicular to the longitudinal axis of the aerosol-generating device.

[0094] As used herein, the term "proximal" refers to the user end (also the mouth end of the aerosol generating device), and the term "distal" refers to the end opposite the proximal end. When referring to the heating chamber or inductor coil, the term "proximal" refers to the area closest to the open end of the heating chamber, and the term "distal" refers to the area closest to the closed end. The ends of the aerosol generating device or heating chamber may also be referred to in relation to the direction of air flow through the aerosol generating device. The proximal end may be referred to as the "downstream end," and the distal end may be referred to as the "upstream end."

[0095] As used herein, the term "length" refers to the major dimension along the longitudinal axis of a heating chamber, the longitudinal axis of an aerosol-generating device, the longitudinal axis of an aerosol-generating article, or the longitudinal axis of a component of an aerosol-generating device or aerosol-generating article.

[0096] As used herein, the term "width" refers to the major dimension across a heating chamber, across an aerosol-generating device, across an aerosol-generating article, or across a component of an aerosol-generating device or article at a particular location along its length. The term "thickness" refers to the dimension in the transverse direction perpendicular to the width.

[0097] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0098] Example A: An aerosol generating device comprising: a main body including a primary coil and a power source; a mouthpiece including a secondary coil and a resistive heating element; the mouthpiece is removably connectable to the main body; and An aerosol generating device, wherein the device is configured such that the primary coil and secondary coil are inductively coupled when the mouthpiece is connected to the main body. Example B: An aerosol generating device as described in Example A, wherein the primary coil and power source form part of a primary wired circuit housed within the main body, and the secondary coil and resistive heating element form part of a secondary wired circuit housed within the mouthpiece. Example C: An aerosol generating device according to Example A or Example B, wherein the primary coil is wired to a power source and the secondary coil is wired to a resistive heating element. Example D: An aerosol generating device according to any one of Examples A to C, in which only the main body is provided with a power source. Example E: An aerosol generating device according to any of Examples A to D, wherein there is no wired connection between the main body and the mouthpiece. Example F: An aerosol-generating device according to any of Examples A to E, wherein the mouthpiece comprises a heated chamber for receiving the aerosol-forming substrate. Example G: The aerosol generating device of Example F, wherein the resistive heating element is disposed at least partially around the heating chamber. Example H: An aerosol generating device according to Example F or Example G, wherein the primary and secondary coils are disposed at the distal end of the heating chamber relative to the longitudinal axis of the device. Example I: An aerosol generating device according to any of Examples A to H, wherein the primary coil and secondary coil are arranged coaxially when the mouthpiece is connected to the main body. Example J: An aerosol generating device as described in Example I, wherein the primary coil and secondary coil are coaxially disposed about the longitudinal central axis of the device when the mouthpiece is connected to the main body. Example K: An aerosol generating device described in any of Examples A to J, wherein the secondary coil is disposed at least partially around the primary coil when the mouthpiece is connected to the main body. Example L: An aerosol generating device described in any of Examples A to K, wherein the device is configured so that power transferred from the primary coil to the secondary coil via inductive coupling is used to heat the resistive heating element. Example M: ​​An aerosol generating device according to example L, wherein the device is configured such that the power used to heat the resistive heating element is supplied from the secondary coil to the resistive heating element by a wired connection. Example N: An aerosol generating device according to any one of Examples A to M, wherein the device is configured to supply an alternating current induced in the secondary coil to the resistive heating element. Example O: An aerosol generating device as described in Example N, wherein the mouthpiece comprises a rectifier disposed in electrical connection between the secondary coil and the resistive heating element. Embodiment P: An aerosol generating device according to any of embodiments A to O, wherein the primary and secondary coils are helical coils, preferably both coils having the same number of turns. Example Q: The aerosol generating device according to any one of Examples A to P, which is equipped with a temperature sensor. Example R: The aerosol generating device of example Q, wherein the temperature sensor comprises a thermocouple. Example S: The aerosol generating device of Example Q or Example R, wherein the primary coil is disposed coaxially around the temperature sensor. Example T: An aerosol generating device according to any one of Examples Q to S, wherein the temperature sensor is located at the proximal end of the primary coil relative to the longitudinal axis of the device. Example U: An aerosol generating device according to any one of Examples A to T, comprising one or both of a half-bridge driver and a half-bridge. Example V: An aerosol generating device according to any one of Examples A to U, comprising an LC filter. Example W: An aerosol generating device according to any one of Examples A to V, wherein the aerosol generating device is a handheld device. Example X: An aerosol-generating device according to any one of Examples A to W, wherein the aerosol-generating device is a heating non-combustion type device. Example Y: An aerosol generating system comprising an aerosol generating device according to any one of Examples A to X and an aerosol-generating article including an aerosol-forming substrate, the aerosol-generating article configured to be at least partially inserted into the heating chamber of the aerosol generating device. Example Z: An aerosol-generating system as described in example Y, wherein the aerosol-forming substrate is a solid aerosol-forming substrate. Example ZA: The aerosol-generating system of example Z, wherein the aerosol-forming substrate comprises one or both of cast leaf and reconstituted tobacco. Example ZB: A method for forming an aerosol in an aerosol generating device, comprising: generating an alternating current in a primary coil housed within a main body of the aerosol generating device; inducing a current in a secondary coil inductively coupled to the primary coil and housed within a mouthpiece of the aerosol generating device by an alternating magnetic field generated by the alternating current in the primary coil, the mouthpiece being removably connected to the main body; Resistively heating a resistance heating element connected to the secondary coil by a wire using a current induced in the secondary coil; generating an aerosol from an aerosol-forming substrate in thermal contact with a resistive heating element.

[0099] Features described with respect to one embodiment may equally apply to other embodiments of the invention.

[0100] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0101] [Figure 1] FIG. 1 shows the aerosol generating device in an exploded configuration. [Figure 2] FIG. 2 shows the aerosol generating device in an assembled configuration. [Figure 3] FIG. 3 shows the aerosol generating device in an exploded configuration. [Figure 4] FIG. 4 shows the aerosol generating device in an assembled configuration. [Figure 5] FIG. 5 shows a diagram of the electrical circuit. DETAILED DESCRIPTION OF THE INVENTION

[0102] Figures 1 and 2 show a cross-sectional side view of an aerosol generating device, which is shown with the mouth end of the device on the right side of the figure.

[0103] Figure 1 shows the aerosol generating device in an exploded configuration. The aerosol generating device comprises a main body 10. The main body 10 comprises a primary coil 12 and a power source 14. The main body 10 further comprises a temperature sensor 16. The main body 10 further comprises control electronics 18 that are wired to both the primary coil 12 and power source 14, and the temperature sensor 16. The control electronics 18 controls the operation of the aerosol generating device.

[0104] The primary coil 12 is disposed coaxially around a temperature sensor 16. The temperature sensor 16 is located at the proximal end of the primary coil 12 relative to the longitudinal axis of the aerosol generating device.

[0105] The aerosol generating device further comprises a mouthpiece 20. The mouthpiece 20 comprises a secondary coil 22 and a resistive heating element 24. The resistive heating element 24 comprises conductive tracks on a flexible insulating substrate. The conductive tracks are wired to the secondary coil 22. The mouthpiece 20 further comprises a heating chamber 26. The resistive heating element 24 coaxially surrounds the heating chamber 26. The heating chamber 26 is configured to receive a cylindrical aerosol-generating article 28 comprising an aerosol-forming substrate.

[0106] The mouthpiece 20 is removably connectable to the main body 10. A detached configuration is shown in Figure 1. In this configuration, the primary coil 12 and secondary coil 22 are not inductively coupled.

[0107] Figure 2 shows the aerosol generating device of Figure 1 in an assembled configuration. In Figure 2, the mouthpiece 20 is connected to the main body 10. In this configuration, the secondary coil 22 coaxially surrounds the primary coil 12, thereby inductively coupling the primary coil 12 and the secondary coil 22. The primary coil 12 and the secondary coil 22 are disposed at the distal end of the heating chamber 26 relative to the longitudinal axis of the aerosol generating device. As shown in Figure 2, the primary coil 12 and the secondary coil 22 are coaxially disposed about the central longitudinal axis of the aerosol generating device when the mouthpiece 10 is connected to the main body 20.

[0108] In use, power supply 14 provides power to primary coil 12 under the control of control electronics 18. Power is then transferred from primary coil 12 to secondary coil 22 via inductive coupling. The power transferred from primary coil 12 to secondary coil 22 via inductive coupling is then supplied by wire connection from secondary coil 22 to resistive heating element 24 and used to heat resistive heating element 24. Resistive heating element 24 heats an aerosol-generating article 28 located within heating chamber 26.

[0109] Control electronics 18 may be configured to supply alternating current to primary coil 12. The alternating current may be induced in secondary coil 22. Mouthpiece 20 may include a rectifier disposed in electrical connection between secondary coil 22 and resistive heating element 24 to supply direct current to resistive heating element 24.

[0110] Figures 3 and 4 show a cross-section of an aerosol generating device in side view. The aerosol generating device of Figures 3 and 4 is shown with the mouth end of the device on the right side of the figure. Figure 3 shows the aerosol generating device in an exploded configuration. Figure 4 shows the aerosol generating device of Figure 3 in an assembled configuration. In the embodiment of Figures 3 and 4, the same reference numbers are used for features similar to those in the embodiment of Figures 1 and 2.

[0111] Unlike the embodiment of Figures 1 and 2, the primary coil 12 and secondary coil 22 of the embodiment of Figures 3 and 4 are each designed with the resistivity required for resistive heating. Both the primary coil 12 and the secondary coil 22 are thereby configured to perform an additional resistive heating function in addition to the inductive coupling function. The aerosol-generating article 28 includes a recess for inserting the primary coil 12 and the temperature sensor 16. The primary coil 12 transfers power to the secondary coil 22 by inductive coupling. In addition, the primary coil 12 functions as a resistive heating element for internally heating the aerosol-generating article 28 when the primary coil 12 is inserted into the recess of the aerosol-generating article 28, as shown in Figure 4.

[0112] The secondary coil 22 receives power from the primary coil 12 by inductive coupling and, in addition, functions as a resistive heating element for externally heating the aerosol-generating article 28 when the aerosol-generating article 28 is inserted into the heating chamber 24, as shown in FIG.

[0113] Figure 5 shows a diagram of the electrical circuit of the aerosol generating device. There is no wired connection between the main body 10 and the mouthpiece 20. The main body 10 only contains the power source 14. The mouthpiece 20 does not contain a power source.

[0114] The primary coil 12 is wired to a power source 14. The primary coil 12 and power source 14 form part of a primary wired circuit housed within the main body 10. The secondary coil 22 and resistance heating element 24 form part of a secondary wired circuit housed within the mouthpiece 20. During use, power is transferred from the primary coil 12 to the secondary coil 22 via inductive coupling between the primary coil 12 and secondary coil 22. The power transferred to the secondary coil 22 via inductive coupling is used to heat the resistance heating element 24.

[0115] Resistive heating element 24 may be an additional component wired to secondary coil 22, such as a conductive track on a flexible insulating substrate wrapped around heating chamber 26, as shown in the embodiment of Figures 1 and 2. Alternatively, secondary coil 22 itself may function as the resistive heating element, as shown in the embodiment of Figures 3 and 4.

[0116] Optionally, an additional resistor 30 may be included within the main body 10. If present, the resistor 30 may represent the inherent resistance of the primary coil 12, which may function as a resistive heating element, as shown in the embodiment of Figures 3 and 4. Alternatively, the resistor 30 may be an additional component (e.g., an additional resistive heating element) wired to the primary coil 12.

Claims

1. An aerosol generating device, comprising: a main body including a primary coil and a power source; A mouthpiece, A secondary coil; A resistance heating element; a mouthpiece comprising: a heating chamber for receiving an aerosol-forming substrate, the resistive heating element being disposed at least partially around the heating chamber; the mouthpiece is removably connectable to the main body; and An aerosol generating device, wherein the device is configured such that when the mouthpiece is connected to the main body, the primary coil and the secondary coil are inductively coupled.

2. 10. The aerosol generating device of claim 1, wherein there is no wired connection between the main body and the mouthpiece.

3. 3. The aerosol generating device according to claim 1, wherein the primary coil and the secondary coil are disposed at a distal end of the heating chamber relative to the longitudinal axis of the device.

4. An aerosol generating device according to any one of claims 1 to 3, wherein when the mouthpiece is connected to the main body, the primary coil and the secondary coil are arranged coaxially around the longitudinal central axis of the device.

5. 5. An aerosol generating device according to claim 1, wherein the secondary coil is disposed at least partially around the primary coil when the mouthpiece is connected to the main body.

6. 6. An aerosol generating device according to any one of claims 1 to 5, wherein the device is configured so that power transferred from the primary coil to the secondary coil via inductive coupling is used to heat the resistance heating element.

7. 7. The aerosol generating device of claim 6, wherein the device is configured such that the power used to heat the resistive heating element is supplied from the secondary coil to the resistive heating element by a wired connection.

8. 8. An aerosol generating device according to claim 1, wherein the device is configured to supply an alternating current induced in the secondary coil to the resistance heating element.

9. 9. The aerosol generating device of claim 8, wherein the mouthpiece comprises a rectifier disposed in electrical connection between the secondary coil and the resistive heating element.

10. 10. An aerosol generating device according to any preceding claim, wherein the primary coil and the secondary coil are helical coils, preferably both coils having the same number of turns.

11. The aerosol generating device according to any one of claims 1 to 10, which is a heating non-combustion type device.

12. An aerosol generation system comprising the aerosol generating device according to any one of claims 1 to 11 and an aerosol-generating article including the aerosol-forming substrate, wherein the aerosol-generating article is configured to be at least partially inserted into a heating chamber of the aerosol generating device.

13. 13. The aerosol-generating system of claim 12, wherein the aerosol-forming substrate is a solid aerosol-forming substrate.

14. 1. A method for forming an aerosol in an aerosol generating device, comprising: generating an alternating current in a primary coil housed within a main body of the aerosol generating device; inducing a current in a secondary coil inductively coupled to the primary coil and housed within a mouthpiece of the aerosol generating device by an alternating magnetic field generated by the alternating current in the primary coil, the mouthpiece being removably connected to the main body and comprising a heating chamber for receiving an aerosol-forming substrate; resistively heating a resistance heating element wired to the secondary coil by the current induced in the secondary coil, the resistance heating element being disposed at least partially around the heating chamber; generating an aerosol from an aerosol-forming substrate in thermal contact with said resistive heating element.

Images