Heater management

Abstract

An electric aerosol generating system includes means for detecting negative conditions, such as a dry heater. The system includes at least one heating element for heating an aerosol forming substrate, a power source, an electric heater, and an electric circuit (109) connected to the power source and including a memory, wherein the electric circuit measures an initial electric resistance R1 of the electric heater; measures a subsequent electric resistance of the electric heater after measuring the initial electric resistance; determines a difference ΔR between the initial electric resistance and the subsequent electric resistance; determines a negative condition if the determined difference between the subsequent electric resistance and the initial electric resistance exceeds a maximum threshold value ΔRmax stored in memory or is less than a minimum threshold value ΔRmin; and is configured to control power supplied to the electric heater based on whether a negative condition is determined, or to provide an indication if a negative condition is determined.

Description

Technology Field

[0001] The present invention relates to heater management. Specific examples disclosed relate to heater management of an electric heating aerosol generation system. Aspects of the present invention relate to an electric heating aerosol generation system and a method of operating an electric heating aerosol generation system. Some described embodiments relate to a system capable of detecting abnormal changes in the electrical resistance of a heating element that may indicate an adverse condition in the heating element. An adverse condition may indicate, for example, a level of depletion of an aerosol-forming substrate within the system. In some described embodiments, the system may be effective when the heating element is made of different electrical resistances. In other embodiments, the detected characteristics of the electrical resistance may be used to determine or select how the system can be operated. Some aspects and features of the present invention may be applied to an electric heating smoking system. Background Technology

[0002] WO 2012 / 085203 discloses an electric heating smoking system comprising: a liquid storage unit for storing a liquid aerosol-forming substrate; an electric heater comprising at least one heating element for heating the liquid aerosol-forming substrate; and an electric circuit configured to determine the depletion of the liquid aerosol-forming substrate based on the relationship between power applied to the heating element and the resulting temperature change of the heating element. In particular, the electric circuit is configured to calculate the rate of temperature rise of the heating element, and a high rate of temperature rise indicates that the wick carrying the liquid aerosol-forming substrate to the heater has dried out. During manufacturing, the system compares the rate of temperature rise with a threshold value stored in memory. If the rate of temperature rise exceeds the threshold value, the system may stop the power supply to the heater.

[0003] The system of WO 2012 / 085203 can calculate the temperature of a heating element using its electrical resistance, which has the advantage of not requiring a dedicated temperature sensor. However, since the system still requires the storage of a threshold value that depends on the resistance of the heating element, it is optimized for heating elements with a specific electrical resistance or a range of resistance.

[0004] However, it may be desirable to enable the system to operate with different heaters. Typically, in systems of the type described in WO 2012 / 085203, the heater is provided as a single-use cartridge along with a supply of a liquid aerosol-forming material. The heating elements within different cartridges may have different electrical resistances. This may be the result of manufacturing tolerances in cartridges of the same type, or it may be because different cartridge designs may be used in the system to provide different user experiences. The system of WO 2012 / 085203 is optimized for a heater having a known specific electrical resistance to be used in the system, which is determined at the time of manufacturing the system.

[0005] In electric heating aerosol generation systems and especially in systems capable of operating with different heaters, it would be desirable to have an alternative system for determining the dryness of the heater or other negative conditions in the heater.

[0006] In an electric heating aerosol generating system having a permanent device part and a consumable part containing an aerosol-forming material, it would also be desirable to be able to easily determine whether the consumable part is "genuine" or a consumable part considered compatible with the device by the manufacturer of the device. This applies to both systems where the heater is part of the consumable and systems where the heater is part of the permanent device.

[0007] In the first aspect of the present invention, as an electric aerosol generating system,

[0008] An electric heater comprising at least one heating element for heating an aerosol-forming substrate;

[0009] Power; and

[0010] The electric circuit is connected to the electric heater and the power source and includes a memory, wherein the electric circuit is

[0011] Measure the initial electric resistance of the electric heater;

[0012] After measuring the initial electric resistance, measure the subsequent electric resistance of the electric heater;

[0013] Determine the difference between the initial electrical resistance and the subsequent electrical resistance;

[0014] It is determined as a negative condition if the determined difference between the subsequent electrical resistance and the initial electrical resistance exceeds the maximum threshold value stored in memory or is less than the minimum threshold value;

[0015] A system is provided that controls the power supplied to the electric heater based on whether a negative condition is determined, or provides an indication when a negative condition is determined.

[0016] One negative condition in an aerosol generation system or aerosol generation device is that the aerosol-forming material in the heater is insufficient or depleted. Generally speaking, the less aerosol-forming material is delivered to the heater to be vaporized, the higher the temperature of the heating element will be for a given applied power. When the power is fixed, the temperature development of the heating element during a heating cycle, or the change in temperature development over multiple heating cycles, can be used to detect whether the amount of aerosol-forming material in the heater is depleted, and in particular whether the aerosol-forming material in the heater is insufficient.

[0017] Another negative condition is the presence of a counterfeit, incompatible, or damaged heater in a system equipped with replaceable or disposable heaters. If the heating element resistance rises faster than expected for a given applied power, it may be because the heater is counterfeit and has different electrical characteristics from a genuine heater, or because the heater is damaged in some way. In either case, the electrical circuit can be configured to cut off the power supply to the heater.

[0018] Another negative condition is the presence of counterfeit, incompatible, old, or damaged aerosol-forming materials within the system. If the heating element resistance rises faster than expected for a given applied power, it may be because the aerosol-forming material is counterfeit or old, and therefore has a higher or lower moisture content than expected. For example, if a solid aerosol-forming material is used, it may dry out if it is very old or stored improperly. If the material is drier than expected, less energy will be used for vaporization than anticipated, and the heater temperature will rise faster. This will result in unexpected changes in the electrical resistance of the heating element.

[0019] By utilizing the difference between the initial and subsequent resistance measurements of an electric heater, the system does not need to determine the actual temperature of the heating element or possess any pre-stored knowledge regarding the heating element's resistance at a given temperature. This allows different approved heaters to be used in the system and permits deviations in absolute resistance caused by manufacturing tolerances of the same type of heater without triggering negative conditions. This also enables the detection of incompatible heaters.

[0020] The electrical circuit can be configured to measure the initial electrical resistance of the heating element and the electrical resistance of the heating element at a time following the initial power transfer from the power source to the electric heater. The initial electrical resistance can be measured prior to the first use of the heater. If the initial resistance is measured prior to the first use of the heater, it can be assumed that the heating element is at approximately room temperature at the time of measurement. Since the expected change in resistance over time may depend on the initial temperature of the heating element, measuring the initial resistance at or near room temperature allows for the establishment of a narrow band for the expected behavior.

[0021] The initial resistance can be calculated by subtracting the assumed parasitic resistance resulting from other electrical components and electrical contacts within the system from the initial measured resistance.

[0022] The system may include a device and a cartridge detachably coupled to the device, wherein the power supply and electrical circuits are within the device, and the electric heater and aerosol-forming material are within the detachable cartridge. As used herein, a cartridge "detachably coupled" to the device means that the cartridge and the device can be coupled and separated from each other without significantly damaging the device or said cartridge.

[0023] The electrical circuit may be configured to detect the insertion and removal of a cartridge from the device. The electrical circuit may be configured to measure the initial electrical resistance of the heater when the cartridge is first inserted into the device, but before any significant heating occurs. The electrical circuit may compare the measured initial resistance with a range of acceptable electrical resistances stored in memory. If the initial resistance is outside the acceptable resistance range, it may be considered counterfeit, incompatible, or damaged. In that case, the electrical circuit may be configured to cut off the power supply until the cartridge is removed and replaced with another cartridge.

[0024] Cartridges with different characteristics can be used with the device. For example, two different cartridges with heaters of different sizes can be used with the device. A larger heater can be used to deliver more aerosol to a user with that personal preference.

[0025] The cartridge may be rechargeable or configured to be disposed of when the aerosol-forming material is depleted.

[0026] An aerosol-forming substrate is a substrate capable of releasing a volatile compound capable of forming an aerosol. The volatile compound can be released by heating the aerosol-forming substrate.

[0027] The aerosol-forming substrate may comprise a plant-based material. The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds released from the aerosol-forming substrate when heated. The aerosol-forming substrate may alternatively comprise a non-tobacco-containing material. The aerosol-forming substrate may comprise a homogenized plant-based material. The aerosol-forming substrate may comprise a homogenized tobacco material. The aerosol-forming substrate may comprise at least one aerosol-forming agent. The aerosol-forming agent is any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol upon use and substantially withstands thermal sensitivity at the operating temperature of the system. Suitable aerosol-forming agents are well known in the art, but are not limited thereto, polyhydric alcohols such as triethylene glycol, 1,3-butanediol, and glycerin; esters of polyhydric alcohols such as glycerol mono-, di-, or triacetate; and includes aliphatic esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol-forming agents are polyhydric alcohols or mixtures thereof, such as triethylene glycol and 1,3-butanediol, and most preferably glycerin. The aerosol-forming agent may include other additives and components, such as flavoring agents.

[0028] The cartridge may comprise a liquid aerosol-forming substrate. For the liquid aerosol-forming substrate, specific physical properties, such as the vapor pressure or viscosity of the substrate, are selected in a manner suitable for use in an aerosol generating system. The liquid preferably comprises a tobacco-containing material containing volatile tobacco flavor compounds released from the liquid upon heating. Alternatively or additionally, the liquid may comprise a non-tobacco material. The liquid may comprise water, ethanol, or other solvents, plant extracts, nicotine solutions, and natural or artificial flavors. Preferably, the liquid further comprises an aerosol-forming agent. Examples of suitable aerosol-forming agents are glycerin and propylene glycol.

[0029] An advantage of providing a liquid storage unit is that the liquid within the storage unit is protected from ambient air. In some embodiments, ambient light cannot enter the liquid storage unit, so light-induced deterioration of the liquid can be avoided. Furthermore, a high level of hygiene can be maintained.

[0030] Preferably, the liquid reservoir is positioned to retain liquid for a predetermined number of puffing cycles. If the liquid reservoir is not refillable and all the liquid within it is consumed, the user must replace the liquid reservoir. During this replacement, contamination of the user by the liquid must be prevented. Alternatively, the liquid reservoir may be refillable. In that case, the aerosol generating system may be replaced after the liquid reservoir has been refilled a specific number of times.

[0031] Alternatively, the aerosol-forming substrate may be a solid substrate. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds released from the substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol-forming agent. Examples of suitable aerosol-forming agents are glycerin and propylene glycol.

[0032] Where the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise one or more of powders, granules, pellets, shreds, spaghetti, strips, or sheets containing, for example, one or more of herbal leaves, tobacco leaves, tobacco rib pieces, reconstituted tobacco, homogenized tobacco, extruded tobacco, cast leaf tobacco, and puffed tobacco. The solid aerosol-forming substrate may be in the form of a roll-your-own cigarette or may be provided in a suitable container or cartridge. Optionally, the solid aerosol-forming substrate may contain additional tobacco or non-tobacco volatile flavor compounds to be released upon heating of the substrate. The solid aerosol-forming substrate may also contain capsules containing, for example, additional tobacco or non-tobacco volatile flavor compounds, and such capsules may melt during heating of the solid aerosol-forming substrate.

[0033] As used herein, homogenized tobacco refers to a material formed by aggregating fine tobacco. Homogenized tobacco may be in the form of a sheet. The homogenized tobacco material may have an aerosol-forming agent content exceeding 5% by dry weight. Alternatively, the homogenized tobacco material may have an aerosol-forming agent content of 5% to 30% by dry weight. A sheet of the homogenized tobacco material may be formed by aggregating fine tobacco obtained by crushing or otherwise subdividing either or both of the leaf lamina and the leaf stem. Alternatively or additionally, the sheet of the homogenized tobacco material may comprise one or more of tobacco powder, tobacco fines, and other fine tobacco by-products formed, for example, during the processing, handling, and delivery of tobacco. A sheet of homogenized tobacco material may comprise one or more endogenous binders that are tobacco endogenous binders that aid in the aggregation of fine tobacco particles, one or more exogenous binders that are tobacco exogenous binders, or a combination thereof; alternatively or additionally, a sheet of homogenized tobacco material may comprise other additives including, but not limited to, tobacco and non-tobacco fibers, aerosol-forming agents, wetting agents, plasticizers, flavoring agents, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0034] Optionally, the solid aerosol-forming substrate may be provided on a thermally stable carrier or embedded in the carrier. The carrier may take the form of powder, granules, pellets, shreds, spaghetti, strips, or sheets. Alternatively, the carrier may be a tubular carrier in which a thin layer of the solid substrate is deposited on the inner surface, the outer surface, or both the inner and outer surfaces. Such a tubular carrier may be formed from, for example, paper, paper-like materials, carbon fiber nonwoven mats, low-mass open-mesh metal screens, or perforated metal foils or any other thermally stable polymer matrix.

[0035] The solid aerosol-forming substrate may be deposited on the surface of a carrier in the form of, for example, a sheet, foam, gel, or slurry. The solid aerosol-forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern to deliver non-uniform flavor during use.

[0036] The electrical circuit may be configured to detect the insertion and removal of an aerosol-forming substrate from the device. The electrical circuit may be configured to measure the initial electrical resistance of the heater when the aerosol-forming substrate is first inserted into the device but before significant heating occurs. The electrical circuit may compare the measured initial resistance with a range of acceptable electrical resistances stored in memory. If the initial resistance is outside the acceptable resistance range, the aerosol-forming substrate may be considered counterfeit, incompatible, or damaged. In that case, the electrical circuit may be configured to cut off the power supply until the aerosol-forming substrate is removed and replaced.

[0037] The electric heater may include a single heating element. Alternatively, the electric heater may include more than one heating element, for example, two, or three, or four, or five, or six or more heating elements. The heating elements or heating elements may be appropriately arranged to heat the liquid aerosol-forming substrate most effectively.

[0038] At least one electric heating element preferably comprises an electrically resistive material. Suitable electrically resistive materials include, but are not limited to: semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic and metal materials. Such composite materials may include doped ceramics or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. 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-, gold-, and iron-containing alloys, and superalloys based on nickel, iron, cobalt, and stainless steel, Timetal®, iron-aluminum alloys, and iron-manganese-aluminum alloys. Timetal® is a registered trademark of Titanium Metals Corporation. In the composite material, the electrically resistive material may be optionally embedded in the insulating material, encapsulated or coated with the insulating material, or vice versa, depending on the energy transfer rate and required external physicochemical properties. The heating element may comprise a metal etched foil insulated between two layers of inert material. In that case, the inert material may include Kapton®, all-polyimide, or mica foil. Kapton® is a registered trademark of EI du Pont de Nemours and Company.

[0039] At least one electric heating element may take any suitable form. For example, at least one electric heating element may take the form of a heating blade. Alternatively, the at least one electric heating element may take the form of a casing or substrate having different conductive parts, or an electrically resistive metal tube. The liquid reservoir may include a disposable heating element. Alternatively, one or more heating needles or rods operating through a liquid aerosol-forming substrate may also be suitable. Alternatively, at least one electric heating element may include a flexible sheet material. Other alternatives include a heating wire or filament, for example, a Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire or a heating plate. Optionally, the heating element may be deposited in or on a rigid carrier material.

[0040] In one embodiment, the heating element comprises a mesh, array, or fabric of conductive filaments. The conductive filaments may define gaps between the filaments, and these gaps may have a width of 10 μm to 100 μm.

[0041] The conductive filament can form a mesh with a size of 160 to 600 Mesh US (± 10%) (i.e., 160 to 600 filaments per inch (± 10%)). The gap width is preferably 75 µm to 25 µm. The percentage of the open area of ​​the mesh, which is the ratio of the gap area to the total area of ​​the mesh, is preferably 25% to 56%. The mesh can be formed using different types of weave or lattice structures. Alternatively, the conductive filament consists of an array of filaments arranged parallel to each other.

[0042] The conductive filament may have a diameter of 10 μm to 100 μm, preferably 8 μm to 50 μm, more preferably 8 μm to 39 μm. The filament may have a round cross-section or a flattened cross-section.

[0043] The area of ​​the mesh, array, or fabric of conductive filaments may be small, preferably 25 mm. 2 It may be less than or equal to and may be included in a handheld system. The mesh, array, or fabric of conductive filaments may be, for example, rectangular and may have dimensions of 5 mm x 2 mm. Preferably, the mesh or array of conductive filaments covers an area of ​​10% to 50% of the area of ​​the heater assembly. More preferably, the mesh or array of conductive filaments covers an area of ​​15% to 25% of the area of ​​the heater assembly.

[0044] Filaments can be formed by etching a sheet material such as foil. This can be particularly advantageous when the heater assembly comprises an array of parallel filaments. When the heating element comprises a mesh or fabric of filaments, the filaments can be formed individually or woven together.

[0045] Preferred materials for conductive filaments are 304, 316, 304L, and 316L stainless steel.

[0046] At least one heating element can heat a liquid aerosol-forming substrate by conduction. The heating element may be in at least partial contact with the substrate. Alternatively, heat from the heating element may be conducted to the substrate by a heat-conducting element.

[0047] Preferably, the aerosol-forming substrate comes into contact with a heating element during use.

[0048] Preferably, the electric aerosol generating system further includes a capillary material for transporting a liquid aerosol forming substrate from a liquid storage unit to an electric heating element.

[0049] Preferably, the capillary material is arranged to come into contact with the liquid in the liquid reservoir. Preferably, the capillary wick extends into the liquid reservoir. In that case, when in use, the liquid is transferred from the liquid reservoir to an electric heater by the capillary action of the capillary wick. In one embodiment, the capillary wick has a first end and a second end, the first end extends into the liquid reservoir to come into contact with the liquid inside, and the electric heater is positioned to heat the liquid in the second end. When the heating element is activated, the liquid in the second end of the capillary wick is vaporized by at least one heating element of the heater to form supersaturated vapor. The supersaturated vapor is mixed with an airflow and transported. While flowing, the vapor condenses to form an aerosol, and the aerosol is returned toward the user's mouth. The liquid aerosol forming material has physical properties including viscosity and surface tension, which cause the liquid to be transported through the capillary wick by capillary action.

[0050] The capillary wick may have a fibrous or sponge structure. The capillary wick preferably comprises a capillary bundle. For example, the capillary wick may comprise a plurality of fibers or threads, or other microbore tubes. The fibers or threads may be aligned entirely along the longitudinal direction of the aerosol generating system. Alternatively, the capillary wick may comprise a sponge-like or foam-like material formed in a rod shape. The rod shape may extend along the longitudinal direction of the aerosol generating system. The structure of the wick forms a plurality of small bores or tubes through which liquid can be transported by capillary action. The capillary wick may comprise any suitable material or combination of materials. Examples of suitable materials are capillary materials, for example, sponge or foamed materials; ceramic or graphite-like materials in the form of fibers or sintered powders; foamed metal or plastic materials; fibrous materials such as cellulose acetate, polyester, or combined polyolefins, for example, spun or extruded fibers, polyethylene, tylene or polypropylene fibers, nylon fibers, or ceramics. Capillary wicks can have any suitable capillary action and porosity to be used with different liquid physical properties. Liquids possess physical properties including, but not limited to, viscosity, surface tension, density, thermal conductivity, boiling point, and vapor pressure, which enable the liquid to be transported through a capillary device by capillary action.

[0051] The heating element may be in the form of a heating wire or filament encircling and optionally supports a capillary wick. The capillary properties of the wick combined with the properties of the liquid ensure that the wick remains wet in the heating zone at all times during normal use with a high amount of aerosol-forming material.

[0052] Alternatively, as described, the heating element may comprise a mesh formed of a plurality of conductive filaments. A capillary material may extend into the gaps between the filaments. The heater assembly may draw a liquid aerosol-forming substrate into the gaps by capillary action.

[0053] The housing may contain two or more different capillary materials, wherein the first capillary material in contact with the heating element has a high thermal decomposition temperature, and the second capillary material in contact with the first capillary material but not with the heating element has a low thermal decomposition temperature. The first capillary material effectively acts as a spacer separating the heating element from the second capillary material so that the second capillary material is not exposed to a temperature exceeding its thermal decomposition temperature. As used herein, "thermal decomposition temperature" refers to the temperature at which a material begins to decompose and lose mass due to the generation of gaseous byproducts. The second capillary material may advantageously occupy a larger volume than the first capillary material and may hold more aerosol-forming substrates than the aerosol-forming substrates of the first capillary material. The second capillary material may have superior wicking performance compared to the first capillary material. The second capillary material may be less expensive or have higher filling performance than the first capillary material. The second capillary material may be polypropylene.

[0054] The power source may be any suitable power source, for example, a DC voltage source. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power source may be a nickel-metal hybrid battery, a nickel-cadmium battery, or a lithium-based battery, for example, a lithium-cobalt, lithium-iron-phosphate, lithium titanate, or lithium-polymer battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require charging and may have a capacity that allows for the storage of sufficient energy for one or more aerosol generation experiences; for example, the power source may have a capacity sufficient to allow for continuous aerosol generation for a period of about 6 minutes, or a period that is a multiple of 6 minutes, corresponding to the usual time taken to smoke a conventional cigarette. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffings or individual activations of the heater.

[0055] Preferably, the aerosol generating system comprises a housing. Preferably, the housing is elongated. 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 these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. Preferably, the material is lightweight and non-brittle.

[0056] Preferably, the electric heating aerosol generating system is portable. The electric heating aerosol generating system may have a size comparable to a conventional cigar or cigarette. The aerosol generating system may have a total length of approximately 30 mm to approximately 150 mm. The electric aerosol generating system may have an outer diameter of approximately 5 mm to approximately 30 mm.

[0057] The electrical circuit preferably includes a microprocessor, more preferably a programmable microprocessor. The system may include a data input port or a wireless receiver that allows software to be uploaded to the microprocessor. The electrical circuit may include additional electrical components. The system may include a temperature sensor.

[0058] When a negative condition is detected, the system may only provide the user with an indication that a negative condition has been detected. This may be done by providing a visual, auditory, or tactile warning. Alternatively or additionally, the electrical circuit may automatically limit or otherwise control the power supplied to the heater when a negative condition is detected.

[0059] If negative conditions are detected, there are many possible ways for the electric circuit to control the power supplied to the electric heater. If an insufficient amount of aerosol-forming material is delivered to the heating element or if the solid aerosol-forming material dries out, it may be desirable to reduce or stop the power supply to the heater. This can ensure a consistent and pleasant experience for the user and mitigate both the possibility of overheating and the potential for the formation of undesirable compounds in the aerosol. The power supply to the heater may be interrupted or limited. The power supply to the heater may be interrupted or limited for a short period of time. However, preferably, the power supply may be interrupted or limited until the heater or the aerosol-forming material is replaced.

[0060] For example, a 6 W pulse may be supplied to the heater initially during puffing. If a negative condition is determined during puffing, the power supply may be limited to a 5 W pulse during the remaining puffing. In some embodiments, the electrical circuit may be configured to supply an unrestricted 6 W pulse to the heater during subsequent puffing until an additional negative condition is determined. However, in other preferred embodiments, the electrical circuit may be configured to supply a limited 5 W pulse to the heater during subsequent puffing until the heater or the aerosol-forming substrate is replaced.

[0061] The smoking system may include a puffing detector for detecting when a user is puffing the smoking system, the puffing detector is connected to an electrical circuit, the electrical circuit is configured to supply power from the power source to the heating element when puffing is detected by the puffing detector, and the electrical circuit is configured to determine whether there is a negative condition during each puff.

[0062] The puffing detector may be a dedicated puffing detector that directly measures airflow through a device such as a microphone-based puffing detector, or it may detect puffing indirectly based, for example, on temperature changes within the device or changes in the electrical resistance of a heating element.

[0063] The electrical circuit may be configured to supply a predetermined power to the heating element during a period Δt1 following the initial detection of puffing or the initial power supply to the heater, and the electrical circuit may be configured to determine the change in the electrical resistance of the heating element based on the electrical resistance measurement of the heating element at time t1 during each puffing process. The period Δt1 may be selected to be immediately after the initial detection of puffing or immediately after the first power application to the heater. This is particularly advantageous during the first use after replacement of a consumable cartridge, in cases where the circuit detects a non-compatible or counterfeit heater or aerosol-forming material. For example, a typical puffing may have a duration of 3 seconds, and the response time of the puffing detector may be about 100 ms. Then, Δt1 may be selected to be between 100 ms and 500 ms during the period of puffing before the heater temperature stabilizes. Alternatively, the period Δt1 may be selected when the temperature of the heating element is expected to stabilize.

[0064] The electric circuit may be configured to cut off the power supply from the power source to the heating element when a negative condition is determined for a predetermined number of sequential or continuous user puffings. The predetermined number of sequential or continuous puffings may be any suitable number. For example, the predetermined number of sequential or continuous puffings may be 1, 2, 3, 4, 5, or 6 times. Preferably, the predetermined number of sequential or continuous puffings is 3 times.

[0065] The electric circuit may be configured to continuously determine whether a negative condition exists, and when a negative condition exists, to limit or cut off the power supply to the heater, and to continue cutting off or reducing the power supply to the heating element until no more negative conditions exist.

[0066] In liquid and wick-based systems, excessive puffing can cause the wick to dry out because the liquid cannot be replaced sufficiently quickly near the heater. In these situations, it is advisable to limit the power supply to the heater to prevent it from becoming too hot or generating undesirable aerosol components. As soon as adverse conditions are detected, power to the heater may be cut off until the user performs subsequent puffing.

[0067] Likewise, if puffing is excessive, the heater cannot be cooled as expected between puffings, so the heater temperature may gradually rise undesirably as puffing continues. This applies to systems based on liquid or solid aerosol forming substrates. When a negative condition is determined, in order to delay the undesirable rise in heater temperature caused by continued puffing, the electrical circuit may be configured to cut off or limit the power supply for the remaining puffing and to limit the power supply to the heater for subsequent puffing until there is no longer a negative condition. If a negative condition occurs during a predetermined number of sequential or consecutive user puffs, the electrical circuit may be further configured to render the heater unusable or to permanently or irreversibly cut off or suppress the power supply from the power source to the heater. As used herein, 'unusable' refers to rendering the heater inoperable. For example, if a negative condition is determined during three consecutive puffs, the electrical circuit may be configured to short-circuit a fuse connected to the heater.

[0068] The electric circuit can be configured to cut off the power supply to the heating element for a predetermined interruption period when negative conditions are present.

[0069] The electric circuit may be configured to cut off the power supply to the heater until the consumable part containing the aerosol-forming substrate or heater is replaced.

[0070] Alternatively or additionally, the electrical circuit may be configured to continuously calculate whether the difference between the initial resistance and the subsequent resistance has reached a maximum or minimum threshold, and to compare the time taken for the difference to reach the threshold with a stored time value; if the time taken to reach the threshold is less than the stored time value or if the difference does not reach the threshold within an expected period, it may be configured to determine that a negative condition exists and to cut off or reduce the power supply to the heater. If the threshold is reached sooner than expected, it may indicate a dry heating element or dry substrate, or an incompatible, counterfeit, or damaged heater. Likewise, if the threshold is not reached within an expected period, it may indicate a counterfeit or damaged heater or substrate. This may enable a rapid determination of a counterfeit, damaged, or incompatible heater or substrate.

[0071] The detection of negative conditions may indicate not only a dry state in the heating element but also a heater exhibiting electrical characteristics outside the expected range. This could be due to defects in the heater caused by material accumulation over its lifespan, or because the heater is an unauthorized or counterfeit heater. For example, if a manufacturer uses stainless steel heating elements, these elements can be expected to have an initial electrical resistance at room temperature within a specific resistance range. Furthermore, the difference between the heater's initial electrical resistance and subsequent resistance can be expected to have a specific value, as this is related to the material of the heating element. The electrical circuit can be configured to determine a negative condition when the difference between the heater's initial and subsequent resistances falls outside the expected range, and to limit or cut off the power supply to the heater based on the result. This can prevent the use of unauthorized heaters.

[0072] Multiple different threshold values ​​may be used to generate different control strategies for different conditions. For example, a maximum threshold and a minimum threshold may be used to set a critical point at which replacement of the substrate heater is required before additional power is supplied. If the difference exceeds the maximum threshold or falls below the minimum threshold, the electrical circuit may be configured to cut off power to the heater until the heater or the aerosol-forming substrate is replaced. One or more intermediate thresholds may be used to detect excessive puffing behavior resulting in a dry state in the heater. The electrical circuit may be configured to cut off power to the heater for a specific period or until subsequent user puffing if the intermediate threshold is exceeded but the maximum threshold is not. One or more intermediate thresholds may also be used to indicate to the user that the aerosol-forming substrate is nearly depleted and needs to be replaced soon. If the intermediate threshold is exceeded but the maximum threshold is not, the electrical circuit may be configured to provide an indication that may be visible, audible, or tactile.

[0073] One method of detecting a counterfeit, damaged, or non-compatible heater is to check the resistance of the heater or the rate of change of the heater's resistance when the heater is first used or inserted into a device or system. An electrical circuit may be configured to measure the initial resistance of the heating element within a specified period after power is supplied to the heater. The specified period may be a short period and may be from 50 ms to 200 ms. In the case of a heater comprising a mesh heating element, the specified period may be about 100 ms. Preferably, the specified period is from 50 ms to 150 ms. The electrical circuit may be configured to measure the initial resistance of the heater as an individual routine of supplying power to the heater to heat the aerosol-forming substrate using much lower power, or may measure the initial resistance of the heater during the first brief moment when the heater is activated before significant heating occurs. The electric circuit may be configured to compare the initial resistance of the heater with a range of acceptable values, and if the initial resistance is outside the range of acceptable values, the electric circuit may be configured to cut off the power supply to the electric heater or provide an indication until the heater or aerosol-forming substrate is replaced.

[0074] If the initial resistance is within the range of acceptable values, the electric circuit may be configured to determine whether there is an acceptable heater and to control the supply of power to the electric heater based on whether there is an acceptable heater, or to provide an indication if there is no acceptable heater.

[0075] The electric circuit can be configured to determine whether there is an acceptable heater within 1 second from the time power is first supplied to the heater.

[0076] As a heater assembly for use in an electric aerosol generating system or electric aerosol generating device, such as the electric aerosol generating system of the first embodiment in the second embodiment,

[0077] An electric heater comprising at least one heating element; and

[0078] It includes an electric circuit connected to an electric heater and containing a memory, wherein the electric circuit is:

[0079] Measure the initial electric resistance of the electric heater;

[0080] After measuring the initial electric resistance, measure the subsequent electric resistance of the electric heater;

[0081] Determine the difference between the initial electrical resistance and the subsequent electrical resistance;

[0082] Determining when the determined difference between the subsequent electric resistance and the initial electric resistance of the electric heater exceeds the maximum threshold value stored in memory or is less than the minimum threshold value;

[0083] A heater assembly is provided that is configured to control the power supplied to an electric heater based on whether a negative condition is determined, or to provide an indication when a negative condition is determined.

[0084] The heater assembly can be configured for use in an aerosol generation system and can be configured to heat an aerosol-forming substrate when in use.

[0085] In a third embodiment, as an electric aerosol generating device for use in an electric aerosol generating system such as the electric aerosol generating system of the first embodiment.

[0086] Power; and

[0087] The electrical circuit includes an electrical circuit connected to a power source and containing memory, wherein the electrical circuit is,

[0088] When in use, it is connected to the electric heater of the above-mentioned electric aerosol generating system;

[0089] Measure the initial electric resistance of the electric heater;

[0090] After measuring the initial electric resistance, measure the subsequent electric resistance of the electric heater;

[0091] Determine the difference between the initial electrical resistance and the subsequent electrical resistance;

[0092] It is determined that a negative condition exists if the determined difference between the subsequent electrical resistance and the initial electrical resistance exceeds the maximum threshold value stored in memory or is less than the minimum threshold value;

[0093] An electric aerosol generator is provided that is configured to control the power supplied to an electric heater based on whether a negative condition is determined, or to provide an indication when a negative condition is determined.

[0094] In a fourth aspect of the present invention, an electric circuit for an electric aerosol generating system such as the electric aerosol generating system of the first aspect, or an electric aerosol generating device such as the electric aerosol generating device of the third aspect, is connected to an electric heater and a power source when in use, and includes a memory,

[0095] Measure the initial electric resistance of the electric heater;

[0096] After measuring the initial electric resistance, measure the subsequent electric resistance of the electric heater;

[0097] Determine the difference between the initial electrical resistance and the subsequent electrical resistance;

[0098] It is determined as a negative condition if the determined difference between the subsequent electrical resistance and the initial electrical resistance exceeds the maximum threshold value stored in memory or is less than the minimum threshold value;

[0099] An electric heater is provided that is configured to control the power supplied to the electric heater based on whether a negative condition is determined, or to provide an indication if a negative condition is determined.

[0100] When in use, the electrical circuit is further connected to a puffing detector to detect when the user puffs on the system, and

[0101] Determine when the electric circuit is connected to the electric heater;

[0102] Measure the initial resistance of the electric heater within a predetermined period after the electric heater is connected to the electric circuit;

[0103] When puffing is detected by a puffing detector, power is supplied from the power source to the heating element;

[0104] Measure the subsequent resistance of the electric heater within a predetermined period after power supply from the power source to the electric heater has commenced;

[0105] Determine the difference between the subsequent resistance and the initial resistance;

[0106] Compare the difference between the subsequent resistance and the initial resistance with at least one of the maximum threshold and minimum threshold stored in memory;

[0107] It is determined that a negative condition exists if the difference exceeds the maximum threshold or is below the minimum threshold;

[0108] If a negative condition is determined, it is further configured to limit the power supplied to the electric heater during puffing, or to cut off the power supply to the electric heater during the remaining puffing based on whether a negative condition is determined.

[0109] In some embodiments, the electric circuit is,

[0110] Store the determination value of the negative condition in memory;

[0111] Based on the determined value of the stored negative condition, the number of times the negative condition is determined consecutively is determined;

[0112] It can be further configured to disable the cartridge if the number of times determined as a negative condition exceeds the maximum threshold.

[0113] The electrical circuit may be configured to render the cartridge unusable by any suitable means. For example, the electrical circuit may be configured to short-circuit a fuse connected to an electric heater.

[0114] In a fifth embodiment, a method for controlling the supply of power to an electric heater of an electric aerosol generating system, such as the electric aerosol generating system of the first embodiment, or an electric aerosol generating device, such as the electric aerosol generating device of the third embodiment, wherein the system or device is an electric heater comprising at least one heating element for heating an aerosol forming substrate, and includes a power source for supplying power to the electric heater, wherein the method comprises:

[0115] Step of supplying power to the electric heater;

[0116] Step of measuring the initial electric resistance of an electric heater;

[0117] Step of measuring the subsequent electric resistance of the electric heater after measuring the initial electric resistance;

[0118] Step of determining the difference between initial electrical resistance and subsequent electrical resistance;

[0119] A step of determining a negative condition if the determined difference between the subsequent electrical resistance and the initial electrical resistance exceeds a maximum threshold value or is less than a minimum threshold value; and

[0120] A method is provided that includes the step of controlling the power supplied to an electric heater based on whether a negative condition is determined, or providing an indication if a negative condition is determined.

[0121] The above method may include the step of measuring the initial electrical resistance of a heating element and the step of measuring the electrical resistance of a heating element at a time after the initial power transfer from a power source to an electric heater.

[0122] The above method may include the step of supplying a constant power to the heater when power is supplied. Alternatively, variable power may be supplied depending on other operating parameters. In that case, the threshold value may be dependent on the power supplied to the heater.

[0123] The above method may include a step of determining the initial electrical resistance prior to the first use of the heater. If the initial resistance is determined prior to the first use of the heater, it can be assumed that the heating element is at approximately room temperature. Since the expected change in resistance over time may depend on the initial temperature of the heating element, measuring the initial resistance at or near room temperature allows for the establishment of a narrow band for the expected behavior.

[0124] The above method may include the step of calculating the initial resistance as the value obtained by subtracting the assumed parasitic resistance resulting from other electrical components and electrical contacts within the system from the initial measured resistance.

[0125] An electric aerosol generating system may include a puffing detector for detecting when a user puffs the system, and the method may include the steps of supplying power from a power source to a heating element when puffing is detected by the puffing detector, determining whether a negative condition exists during each puffing, and cutting off the power supply from the power source to the heating element if a negative condition exists for a predetermined number of sequential user puffs.

[0126] The above method may include a step of cutting off the supply of power from the power source to the heating element when negative conditions exist.

[0127] The above method may include the step of continuously determining whether a negative condition exists, and the step of cutting off the power supply to the heater when a negative condition exists and continuously cutting off the power supply to the heating element until no more negative conditions exist.

[0128] The above method may include a step of cutting off the power supply to the heating element for a predetermined interruption period when negative conditions exist.

[0129] Alternatively or additionally, the method may include the step of continuously calculating whether the difference exceeds a maximum threshold value or is less than a minimum threshold value, and the step of comparing the time taken to reach the threshold value with a stored time value, and if the time taken to reach the threshold value is less than the stored time value, a negative condition is determined and the power supply to the heater is controlled.

[0130] In some embodiments, the electric aerosol generating system further comprises a removable cartridge and a device configured to removablely receive the removable cartridge, wherein the removable cartridge comprises an electric heater and a liquid aerosol forming substrate, and the device comprises a power source and an electrical circuit, and the electrical circuit is connected to a puffing detector for detecting when a user puffs on the system. In such embodiments, the method comprises:

[0131] A step of measuring the initial electric resistance of an electric heater before puffing is detected by a puffing detector;

[0132] A step of supplying power from the power source to the heating element when puffing is detected by a puffing detector;

[0133] A step of measuring the subsequent resistance of the electric heater within a predetermined period after power supply from the power source to the electric heater has commenced;

[0134] Step of determining the difference between subsequent resistance and initial resistance;

[0135] A step of comparing the difference between the subsequent resistance and the initial resistance with at least one of the maximum threshold value and the minimum threshold value stored in memory;

[0136] A step of determining that a negative condition exists if the difference exceeds a maximum threshold or is less than a minimum threshold; and

[0137] If a negative condition is determined, the method may further include a step of limiting the power supplied to the electric heater during puffing, or if a negative condition is determined, cutting off the power supply to the electric heater during the remaining puffing.

[0138] In some embodiments, the above method is:

[0139] A step of determining when the electric circuit is connected to the electric heater; and

[0140] It further includes the step of measuring the initial resistance of the electric heater within a predetermined period after being connected to the electric heater.

[0141] In a sixth aspect of the present invention, a method for detecting an incompatible or damaged heater in an electric aerosol generating system, such as the electric aerosol generating system of the first aspect, or an electric aerosol generating device, such as the electric aerosol generating device of the third aspect, wherein the system or device is an electric heater comprising at least one heating element for heating an aerosol forming substrate, and comprises a power source for supplying power to the electric heater, the method comprising:

[0142] Step of supplying power to the heater;

[0143] Step of measuring the initial electric resistance of an electric heater;

[0144] Step of measuring the subsequent electric resistance of the electric heater after measuring the initial electric resistance;

[0145] Step of determining the difference between initial electrical resistance and subsequent electrical resistance;

[0146] A method is provided comprising the step of determining an incompatible or damaged heater when the difference between the subsequent electrical resistance and the initial electrical resistance exceeds a maximum threshold or is less than a minimum threshold, or reaches a threshold stored in memory at a time other than the expected period.

[0147] The above method may include the step of cutting off the power supply to the electric heater or providing an indication until the heater or aerosol-forming substrate is replaced when it is determined to be an incompatible heater.

[0148] The above method may further include the steps of measuring the initial resistance of the heater or the rate of change of the initial resistance of the heater within a predetermined period after power is supplied to the heater, comparing the initial resistance of the heater or the rate of change of the initial resistance of the heater with a range of acceptable values, and, if the initial resistance or the rate of change is outside the range of acceptable values, cutting off the power supply to the electric heater or providing an indication until the heater or the aerosol-forming substrate is replaced.

[0149] The predetermined period may be a short period and may be 50 ms to 200 ms. For a heater including a mesh heating element, the predetermined period may be about 100 ms. Preferably, the predetermined period is 50 ms to 150 ms.

[0150] Determination of the initial resistance change rate over a specified period can be achieved by taking multiple resistance measurements at different times over the specified period and calculating the resistance change rate based on the multiple resistance measurements.

[0151] The above method may further include a step of detecting when a heater or an aerosol-forming substrate is inserted into the system. The above method may be performed immediately after detecting that the heater or an aerosol-forming substrate has been inserted into the system.

[0152] In a seventh aspect of the present invention, a computer program product capable of being directly loaded into the internal memory of a microprocessor is provided, the product comprises a software code portion for performing the steps of a fifth aspect or a sixth aspect when the product is operated on a microprocessor of an electric aerosol generating system, the system comprises an electric heater comprising at least one heating element for heating an aerosol forming substrate and a power source for supplying power to the electric heater, and the microprocessor is connected to the electric heater and the power source.

[0153] Computer program products may be provided as downloadable parts of software or recorded on computer-readable storage media.

[0154] According to the eighth aspect of the present invention, a computer-readable storage medium is provided in which a computer program according to the seventh aspect is stored.

[0155] The features described in connection with one aspect of the present invention may be applied to other aspects of the present invention. In particular, the features described in connection with the first aspect may be applied to the second, third, and fourth aspects of the present invention. The features described in connection with the first, second, third, and fourth aspects of the present invention may also be applied to the fifth, sixth, and seventh aspects of the present invention. Brief explanation of the drawing

[0156] The present invention will be further explained merely by example with reference to the accompanying drawings, wherein: FIGS. 1a to 1d are schematic diagrams of a system according to an embodiment of the present invention; FIG. 2 is an exploded view of a cartridge for use in a system as illustrated in FIG. 1a to 1d; FIG. 3 is a detailed view of a heater filament illustrating the meniscus of a liquid aerosol-forming substrate between the filaments; Figure 4 is a schematic diagram of the change in resistance of the heater during user puffing; FIG. 5 is an electrical circuit diagram illustrating a method by which the resistance of a heating element can be measured; FIG. 6 illustrates the control process after the detection of negative conditions; FIG. 7 is a schematic diagram of a first alternative aerosol generation system; FIG. 8 is a schematic diagram of a second alternative aerosol generation system; FIG. 9 is a flowchart illustrating a method for detecting unauthorized, damaged, or incompatible heaters. Specific details for implementing the invention

[0157] FIGS. 1a to 1d are schematic diagrams of an electric heating aerosol generating system including a cartridge according to an embodiment of the present invention. FIG. 1a is a schematic diagram of an aerosol generating device (10) and individual cartridges (20) together forming an electric heating aerosol generating system.

[0158] The cartridge (20) includes an aerosol-forming material and is configured to be received within a cavity (18) in the device. The cartridge (20) must be replaceable by the user when the aerosol-forming material provided in the cartridge is depleted. FIG. 1a illustrates the cartridge (20) immediately before being inserted into the device, and the arrow (1) in FIG. 1a indicates the insertion direction of the cartridge.

[0159] The aerosol generating device (10) is portable and has a size comparable to a conventional cigar or cigarette. The device (10) includes a main body (11) and a mouthpiece (12). The main body (11) includes a battery (14), such as a lithium iron phosphate battery, an electrical circuit (16), and a cavity (18). The electrical circuit (16) includes a programmable microprocessor. The mouthpiece (12) is connected to the main body (11) by a hinged connection (21) and can move between an open position, such as the bar shown in FIG. 1, and a closed position, such as the bar shown in FIG. 1d. The mouthpiece (12) is placed in an open position to allow insertion and removal of a cartridge (20), and is placed in a closed position when the system is used to generate an aerosol. The mouthpiece includes a plurality of air inlets (13) and outlets (15). When in use, the user places their mouth over the outlet and sucks or puffs to draw air from the air inlet (13) through the mouthpiece to the outlet (15), and then draws it into the user's mouth or lungs. The internal partition (17) forces the air flowing through the mouthpiece (12) to pass through the cartridge.

[0160] The cavity (18) has a circular cross-section and is sized to accommodate the housing (24) of the cartridge (20). An electrical connector (19) is provided on the side of the cavity (18) to provide an electrical connection between the control electronic device (16) and the corresponding electrical contacts on the battery (14) and the cartridge (20).

[0161] FIG. 1b illustrates the system of FIG. 1a in which a cartridge is inserted into a cavity (18) and a cover (26) is removed. In this position, an electrical connector is placed on an electrical contact on the cartridge.

[0162] FIG. 1c illustrates the system of FIG. 1b in which the cover (26) is completely removed and the mouthpiece part (12) moves to a closed position.

[0163] FIG. 1d illustrates the system of FIG. 1c in which the mouthpiece portion (12) is in a closed position. The mouthpiece portion (12) is held in a closed position by a latching mechanism. The mouthpiece portion (12) in the closed position holds a cartridge in electrical contact with the electrical connector (19), thereby maintaining a good electrical connection during use regardless of the orientation of the system.

[0164] FIG. 2 is an exploded view of a cartridge (20). The cartridge (20) comprises a generally circular cylindrical housing (24) having a size and shape selected to be accommodated within a cavity (18). The housing contains a capillary material (27, 28) immersed in a liquid aerosol forming substrate. In this embodiment, the aerosol forming substrate comprises 39 wt% glycerin, 39 wt% propylene glycol, 20 wt% water and flavoring agent, and 2 wt% nicotine. The capillary material is a material that actively transfers liquid from one end to the other and may be made from any suitable material. In this embodiment, the capillary material is formed of polyester.

[0165] The housing has an open end to which the heater assembly (30) is fixed. The heater assembly (30) comprises a substrate (34) having a hole (35) formed inside, a pair of electrical contacts (32) fixed to the substrate and separated from each other by a gap (33), and a plurality of conductive heater filaments (36) connecting the hole and fixed to the electrical contacts on opposite sides of the hole (35).

[0166] The heater assembly (30) is covered by a removable cover (26). The cover comprises a liquid-impermeable plastic sheet that is bonded to the heater assembly with adhesive but can be easily peeled off. Tabs are provided on the sides of the cover so that a user can grasp the cover when peeling it off. Although the use of adhesive is described as a method of securing the impermeable plastic sheet to the heater assembly, it will be obvious to those skilled in the art that other methods similar to those in the art, including heat sealing or ultrasonic welding, may also be used as long as the cover can be easily removed by the consumer.

[0167] In the cartridge of FIG. 2, there are two individual capillary materials (27, 28). A disc of the first capillary material (27) is provided to contact a heating element (36, 32) when in use. A larger body of the second capillary material (28) is provided on the side opposite the first capillary material (27) with respect to the heater assembly. Both the first capillary material and the second capillary material possess a liquid aerosol-forming substrate. The first capillary material (27), which is in contact with the heating element, has a higher thermal decomposition temperature (at least 160°C) than the second capillary material (28). o C or more, for example, approximately 250 oC) has. The first capillary material (27) effectively acts as a spacer separating the heating element (36, 32) from the second capillary material (28) so that the second capillary material is not exposed to a temperature exceeding its thermal decomposition temperature. A thermal gradient across the first capillary material causes the second capillary material to be exposed to a temperature below its thermal decomposition temperature. The second capillary material (28) may be selected to have superior moisture carrying performance than the first capillary material (27), may hold more liquid per unit volume than the first capillary material, and may be cheaper than the first capillary material. In this embodiment, the first capillary material is a heat-resistant material such as fiberglass or a fiberglass-containing material, and the second capillary material is a polymer such as a suitable capillary material. An exemplary suitable capillary material includes the capillary material described herein, and in an alternative embodiment, may include high-density polyethylene (HDPE) or polyethylene terephthalate (PET).

[0168] The capillary material (27, 28) is advantageously oriented within the housing (24) to transport the liquid to the heater assembly (30). When a cartridge is assembled, the heater filaments (36, 37, 38) may come into contact with the capillary material (27), so that the aerosol-forming substrate may be transported directly to the mesh heater. FIG. 3 is a detailed view of the filaments (36) of the heater assembly showing the meniscus (40) of the liquid aerosol-forming substrate between the heater filaments (36). It can be seen that most of the heat generated by the heater assembly is transferred directly to the aerosol-forming substrate by the aerosol-forming substrate coming into contact with most of the surface of each filament.

[0169] Therefore, in normal operation, the liquid aerosol forming material comes into contact with most of the surface of the heater filament (36). However, when most of the liquid material in the cartridge is used, less liquid aerosol forming material will be delivered to the heater filament. As the liquid vaporizes less, less energy is used by the enthalpy of vaporization, and more energy supplied to the heating filament is directed toward raising the temperature of the heating filament. Thus, as the heating element dries out, the rate of temperature increase of the heating element for a given applied power will increase. The heating element may dry out because the aerosol forming material in the cartridge is almost completely consumed, or because the user takes very long or very frequent puffing, and the liquid cannot be delivered to the heater filament as quickly as it vaporizes.

[0170] When in use, the heater assembly operates by resistance heating. Current passes through the filament (36) under the control of the control electronic device (16) to heat the filament within a desired temperature range. The mesh or array of filaments has a significantly larger electrical resistance than the electrical contact (32) and electrical connector (19), so that the high temperature is confined to the filament. In such an embodiment, the system is configured to generate heat by providing current to the heater assembly in response to user puffing. In another embodiment, the system may be configured to generate heat continuously while the device is in the "on" state. Different materials for the filament may be suitable for different systems. For example, in a continuous heating system, Ni-Cr filaments are suitable because they have a relatively low specific heat capacity and are compatible with low-current heating. In a puffing operation system where heat is generated in short bursts using high-current pulses, stainless steel filaments with a high specific heat capacity may be more suitable.

[0171] The system includes a puffing sensor configured to detect when a user inhales air through the mouthpiece. The puffing sensor (not shown) is connected to a control electronic device (16), and the control electronic device (16) is configured to supply current to the heater assembly (30) only when it is determined that the user is puffing the device. Any suitable airflow sensor may be used as a puffing sensor, such as a microphone or a pressure sensor.

[0172] To detect an increase in the rate of such temperature change, the electric circuit (16) is configured to measure the electrical resistance of the heater filament. In such an embodiment, the heater filament is formed of stainless steel and thus has a positive resistance temperature coefficient. This means that as the temperature of the heater filament rises, its electrical resistance increases. In another embodiment, the heater filament may be formed of a material having a negative resistance coefficient, and it will be understood that the electrical resistance decreases as the temperature of the heater filament rises.

[0173] FIG. 4 is a schematic diagram of the change in resistance of the heater during user puffing. The x-axis represents the time after the initial detection of user puffing and the subsequent power supply to the heater. The y-axis represents the electrical resistance of the heater assembly. It can be seen that the heater assembly has an initial resistance (R1) before any heating occurs. R1 is the parasitic resistance (R) resulting from the electrical contact (32), the electrical connector (19), and the contact between them. P It consists of the resistance (R0) of the heater filament and the heater filament. When power is applied to the heater during user puffing, the temperature of the heater filament rises, and consequently, the electrical resistance of the heater filament rises. As shown, at time t1, after a period Δt1 from the power supply from the power source to the heater, the resistance of the heater assembly is R2. Therefore, the change in the electrical resistance of the heater assembly from the initial resistance to the resistance at time t1 is ΔR = R2 - R1.

[0174] In this embodiment, parasitic resistance R P It is assumed that it does not change when the heater filament is heated. This is R P This is because it is attributed to non-heating components such as electric contacts (32) and electric connectors (19). R P The value of is assumed to be the same for all cartridges, and the value is stored in the memory of the electrical circuit.

[0175] To detect a rapid temperature rise of the heater filament indicating the drying state of the heater filament, a change in the resistance of the heater filament can be monitored. The electrical circuit can be configured to determine the change in resistance by determining the difference between the measurement of the initial electrical resistance R1 of the heater filament before power is supplied to the heating element—that is, before puffing—and the measurement of the electrical resistance R2 of the heater filament after a predetermined period Δt1 from the time power is supplied to the heater filament. Additionally, the electrical circuit determines the difference ΔR of the change in resistance to a predetermined maximum threshold value ΔR max It can be configured to determine whether it indicates an unacceptable rapid temperature rise by comparing with.

[0176] Both R2 and R1 are measured values, and ΔR max It is stored in memory. Ideally, the value of R1 is measured before any heating occurs, that is, before the heater is initially activated. This initial measurement can be used for all subsequent puffings to avoid any errors caused by residual heat from previous puffings. In this way, the electrical resistance initially measured before any heating occurs is R 1ref It can be referred to as.

[0177] R 1refR1 can be measured only once for each cartridge, and the detection system used to determine when a new cartridge is inserted, or R1, can be measured whenever the system is turned on. However, preferably, the electrical circuit updates R after a predetermined period during which power is not supplied to the heater filament. 1ref It is configured to periodically take measurements of. The specified period is typically 3 minutes, but may be any appropriate time required for the heater filament to cool from the operating temperature to room temperature. R 1ref Periodic updates to it can recalibrate the electrical circuit to compensate for changes in ambient temperature and changes in the state of the heater filament.

[0178] In this embodiment, software operating on a microprocessor within an electrical circuit performs the following comparison to determine a negative condition:

[0179] R2> R 1ref + ΔR max On this side, a dry state exists in the heater. (1)

[0180] Other negative conditions besides dry heater conditions can be detected in a similar manner. For example, if a cartridge having a heater formed of a material having a different resistance temperature coefficient is used in the system, the electrical circuit can detect negative conditions and be configured not to supply power to the heater. In this embodiment, the heater is formed of stainless steel. A cartridge having a heater formed of Ni-Cr may have a lower resistance temperature coefficient, which means that its resistance may rise more slowly with increasing temperature. As such, the minimum threshold value ΔR min (This corresponds to the lowest temperature rise during the expected period Δt1 for the stainless steel heater) can be stored in the electrical circuit's memory. The electrical circuit determines the minimum threshold value ΔR for the resistance change between R2 and R1ref. minIf less than, it can be configured to determine negative conditions corresponding to unauthorized cartridges present in the system.

[0181] Therefore, the system consists of R2 and R 1ref It can be configured to determine negative conditions by comparing the high threshold value and the low threshold value stored between them. R 1ref It can also be compared to thresholds to verify whether it is within the expected range. These may involve different actions taken depending on whether even one stored high threshold is exceeded or if that high threshold is exceeded. For example, if the highest threshold is exceeded, the circuit may cut off the additional supply of power until the heater and / or substrate is replaced. This may indicate a completely depleted substrate or a damaged or incompatible heater. A lower threshold can be used to determine when the substrate is nearly depleted. If such a lower threshold is exceeded but the higher threshold is not, the circuit may simply provide an indicator, such as a light LED, to show that the substrate needs to be replaced soon.

[0182] R to determine whether the heater cools sufficiently between puffing 1ref The difference between and R2 can be continuously monitored. If the user puffs too frequently and the difference does not fall below a cooling threshold between puffs, the electrical circuit may cut off or limit the power supply to the heater until the difference falls below the cooling threshold. Alternatively, to determine whether sufficient cooling is occurring, a comparison can be made between the maximum value of the difference during puffing and the minimum value of the difference after puffing.

[0183] In addition, the difference between R1 and R2 is continuously monitored, and the time to reach the threshold can be compared with the time threshold. R 1refIf the difference between and R2 reaches the threshold much faster or slower than expected, it may indicate a negative condition, such as a non-compatible heater. The rate of change can also be determined and compared to the threshold. If it rises very quickly or very slowly, it may indicate a negative condition. These techniques can enable the detection of non-compatible heaters very quickly.

[0184] FIG. 5 is a schematic electrical circuit diagram showing a method for measuring the resistance of a heating element. In FIG. 5, the heater (501) is voltage ( V2 It is connected to a battery (503) that provides ). The heater resistance to be measured at a specific time is R 히터 is. In series with the heating element (501), a known resistance ( r An additional resistor (505) having ) is connected to ground and voltage ( V2 The voltage that is in the middle between ) V1 It is inserted and connected to ). The microprocessor (507) of the heater (501) R 히터 To measure the resistance, both the current passing through the heater (501) and the voltage across the heater (501) can be determined. Then, the resistance can be determined using the following well-known formula:

[0185] (2)

[0186] In Fig. 5, the voltage across the heater is V2-V1 The current passing through the heater is I is. Therefore:

[0187] (3)

[0188] An additional resistor (505) with a known resistance (r) is above (2) It is used again to determine the current (I). The current passing through the resistor (505) is I, and the voltage across the resistor (505) is V1. Therefore:

[0189] (4)

[0190] So, food (5) and (6) Combining them gives the following:

[0191] (5)

[0192] Therefore, when the aerosol generating system is in use, the microprocessor (507) V2 and V1 It can measure, r If the value of is known, the heater resistance at different times is R 히터 can decide.

[0193] The electric circuit can control the power supply to the heater in some different way after a negative condition is detected. Alternatively or additionally, the electric circuit can simply provide the user with an indication that a negative condition has been detected. The system may include an LED or a display, or a microphone, and these components can be used to issue a warning of the negative condition to the user.

[0194] FIG. 6 illustrates a control process for a puffing operation system according to the present invention. FIG. 6 illustrates four consecutive puffings, P1, P2, P3, and P4. The first puffing P1 is a normal puffing without abnormal conditions. The three subsequent puffings P2, P3, and P4 all have a high threshold value ΔR max It is abnormal puffing that exceeds .

[0195] Each puffing is detected at time t1, when power is supplied to the heater filament. At time t1, the resistance of the heater filament is denoted as R1. The initial resistance R1 of the heater filament for the first puffing P1 is the initial reference resistance R measured before heating begins. 1refIt is identical to. The subsequent abnormal puffings P2, P3, and P4 are the initial reference resistance R at time t1. 1ref It exhibits a higher initial resistance R1. This indicates that the heater filament does not have sufficient time to cool back to room temperature between puffings. The resistance of the heater filament is measured at time t2 after a predetermined time Δt1 following the detection of puffing. Each puffing ends at time t3, and the total duration is Δt puff am.

[0196] In the control process of Fig. 6, the electric circuit stops supplying power to the heater as soon as it detects that a high threshold has been exceeded, until the user's puffing ends. This applies to time t during the second, third, and fourth puffings P2, P3, and P4. h It appears in. This can be useful for preventing the heater from getting very hot, even if the user is puffing excessively. In addition to cutting off power, it can provide an indication that a threshold has been reached.

[0197] When a new user puff is detected, power is restored to the heater. This is illustrated in puffs P3 and P4. While one example exceeding the threshold may result from a very long user puff, some continuous puffing while exceeding a high threshold is more likely to result in the cartridge becoming empty. Therefore, in this embodiment, for a specific number of continuous puffs, typically 3 puffs, ΔR is the threshold ΔR max If this value is exceeded, the fuse inside the cartridge short-circuits, rendering the cartridge unusable. For example, the cartridge may be unusable in other ways, such as the electrical circuit cutting off the supply of additional power to the heater filament until the cartridge is replaced or refilled, or until the user performs a reset operation.

[0198] In most embodiments, the cartridge is detachable from the device. The user can remove the cartridge from the device to discard or refill the cartridge when the liquid aerosol-forming material in the cartridge is empty. The user can also remove a cartridge that is partially empty and still contains the liquid aerosol-forming material.

[0199] The user can insert a used cartridge into the device. For example, the user can insert a refilled or partially empty cartridge into the device. If the user inserts a recently used cartridge into the device, there may not be enough time for the heater to cool to room temperature after previous use. When the heater filament is still hot, the device's electrical circuit [determines] the initial resistance R of the heater filament 1ref If measured, this can distort the determination of negative conditions by the electric circuit and result in the heater filament being heated to an undesirable temperature.

[0200] Therefore, the electric circuit can be configured to determine whether the temperature of the heater in the recently inserted cartridge is stable. In other words, the electric circuit can be configured to determine whether the recently inserted cartridge is at a cooling temperature or at room temperature. This is because when the heater filament is hot, the electric circuit determines the initial resistance R of the heater filament. 1ref It can effectively block or suppress the measurement of.

[0201] In most embodiments, the electrical circuit is configured to determine when the cartridge is received within the device. As such, the electrical circuit is configured to determine when the cartridge is removed from the device and when the cartridge is inserted into the device.

[0202] When the electrical circuit determines that the cartridge is inserted into the device, the electrical circuit determines the preliminary resistance R of the heater filament p1It can be configured to measure the subsequent preliminary resistance R of the heater filament after a predetermined time ΔT2, typically about 1 second to about 2 seconds. p2 It can be configured to measure.

[0203] The electrical circuit is the measured preliminary resistance R p1 , R p2 The difference between them ΔR p It can be configured to determine. When the temperature of the heater filament stabilizes, the size difference │R p │ must be less than or equal to 0. However, the magnitude of the difference |ΔR p If | is relatively large, this indicates that the heater filament temperature is unstable. Difference |ΔR p If | is relatively large, this indicates that the heater filament is at a high temperature and cools over the period ΔT2. The electrical circuit is the difference ΔR p ΔR is the minimum threshold value pmin It can be configured to compare with and determine whether the temperature of the heater filament is stable based on the comparison. The electric circuit is the difference |ΔR p | is the minimum threshold value ΔR pmin If it is larger, it can be configured to determine that the temperature of the heater filament is unstable. The electrical circuit can be configured to perform the following comparison:

[0204] |R p2 - R p1 |> ΔR pmin If so, the heater temperature is not stable. (6)

[0205] R p2 and R p1 Both are measured values, and ΔR pmin It is stored in memory.

[0206] In some embodiments, the electric circuit has the magnitude of the difference |ΔR p | is the minimum threshold value ΔR pminYou will understand that it can be configured to compare with. The electric circuit is the difference |ΔR p The magnitude of | is the minimum threshold value ΔR pmin In the case of a larger value, it can be configured to determine that the temperature of the heater filament is not stable.

[0207] If the electric circuit determines that the temperature of the heater filament is not stable, the electric circuit can block the supply of power to the heater filament, and the initial resistance R 1ref It cannot be measured and stored. The electrical circuit periodically or continuously has a subsequent reserve resistance R p2 Measure the initial preliminary resistance R p1 Difference ΔR for p Determine the difference ΔR until there is a difference within the expected level for the heater filament at a stable temperature. p The minimum threshold value ΔR as close to zero as possible pmin It can be configured to be compared with.

[0208] When the electric circuit determines that the temperature of the heater filament is stable, the electric circuit has an initial reference resistance R 1ref It can be configured to determine and perform the aforementioned conventional process.

[0209] In some embodiments, the electrical circuit has a single reserve resistor R after the insertion of a new cartridge. p1 It measures periodically, and the previous resistance R, which is measured and stored before the previous cartridge is removed, is measured. 1ref and preliminary resistance R p1 The difference ΔR between them p It can be configured to determine.

[0210] Although the present invention has been described with reference to a cartridge-based system having a mesh heater, the same negative condition detection method can be used in other aerosol generation systems.

[0211] FIG. 7 illustrates an alternative system that also uses a liquid substrate and a capillary material according to the present invention. The electric heating aerosol generating system (100) of FIG. 7 comprises a housing (101) having a mouthpiece end (103) and a body end (105). At the body end, a power source in the form of a battery (107) and an electric circuit (109) is provided. A puffing detection system (111) is also provided in cooperation with the electric circuit (109). At the mouthpiece end, a liquid reservoir in the form of a liquid (115) containing cartridge (113), a capillary wick (117), and a heater (119) is provided. Note that the heater is schematically shown only in FIG. 7. One end of the capillary wick (117) extends into the cartridge (113), and the other end of the capillary wick (117) is surrounded by the heater (119). The heater is connected to an electrical circuit via a connection part (121), which can pass along the outside of the cartridge (113) (not shown in FIG. 7). The housing (101) includes an air inlet (123), an air outlet (125) at the end of the mouthpiece, and an aerosol chamber (127).

[0212] When in use, the operation is as follows. Liquid (115) is transported by capillary action from the cartridge (113) to the other end of the wick (117) that extends into the cartridge, and to the other end of the wick surrounded by the heater (119). When the user inhales the aerosol generating system at the air outlet (125), ambient air is drawn in through the air inlet (123). In the arrangement shown in FIG. 7, the puffing detection system (111) detects puffing and activates the heater (119). The battery (107) supplies electrical energy to the heater (119) to heat the end of the wick (117) surrounded by the heater. The liquid within the end of the wick (117) is vaporized by the heater (119) to produce supersaturated vapor. At the same time, the vaporized liquid is replaced by additional liquid that moves along the wick (117) by capillary action. The generated supersaturated vapor is mixed with the airflow and transported from the air inlet (123) to the airflow. In the aerosol chamber (127), the vapor condenses to form an inhalable aerosol, and the aerosol is transported toward the outlet (125) into the user's mouth.

[0213] In the embodiment shown in FIG. 7, the electric circuit (109) and the puffing detection system (111) are programmable as in the embodiments of FIG. 1a through 1d.

[0214] Capillary wicks can be manufactured from various porous or capillary materials and preferably possess known, established capillary phenomena. Examples include ceramic or graphite-based materials in the form of fibers or calcined powders. By using wicks of different porosity, different liquid properties such as density, viscosity, surface tension, and vapor pressure can be accommodated. When the liquid reservoir contains a sufficient amount of liquid, the wick must be suitable for delivering the required amount of liquid to the heater.

[0215] The heater includes at least one heating wire or filament extending around a capillary wick.

[0216] As in the system described with reference to FIGS. 1 to 3, when the liquid in the cartridge is completely consumed or the user takes a very long and deep puff, the capillary material forming the wick may dry out near the heater wire. In the same manner as described with reference to the system of FIGS. 1 to 3, the change in resistance of the heater wire during the first part of each puff can be used to determine whether negative conditions, such as a dry wick, are present.

[0217] The system of the type illustrated in Fig. 7 may have significant variations in heater resistance even between cartridges of the same type due to variations in the length of the heater wire wrapping around the wick. The present invention is particularly advantageous because it does not require the electrical circuit to store a maximum heater resistance value as a threshold; instead, this is an increase in resistance relative to the initial measured resistance used.

[0218] FIG. 8 illustrates another aerosol generating system capable of implementing the present invention. An embodiment of FIG. 8 is an electric heating tobacco device in which a tobacco-based solid substrate is heated but not burned to generate an aerosol for inhalation. In FIG. 8, the components of the aerosol generating device (700) are illustrated in a simplified manner and are not illustrated at actual scale. Elements irrelevant to understanding such an embodiment are omitted to simplify FIG. 8.

[0219] An electric heating aerosol generator (200) comprises a housing (203) and an aerosol forming substrate (210), for example, a cigarette. The aerosol forming substrate (210) is pushed into a cavity (205) formed by the housing (203) and is thermally close to a heater (201). The aerosol forming substrate (210) emits a wide range of volatile compounds at different temperatures. By controlling the operating temperature of the electric heating aerosol generator (200) to be below the emission temperature of some volatile compounds, the emission or formation of smoke components can be avoided.

[0220] Inside the housing (203) is an electric power source (207), for example, a rechargeable lithium-ion battery. An electric circuit (209) is connected to the heater (201) and the electric power source (207). The electric circuit (209) controls the power supplied to the heater (201) to control the temperature of the heater. An aerosol-forming substrate detector (213) can detect the presence and identity of an aerosol-forming substrate (210) that is thermally close to the heater (201) and signal the presence of the aerosol-forming substrate (210) to the electric circuit (209). The provision of the substrate detector is optional. An airflow sensor (211) is provided within the housing and connected to the electric circuit (209) to detect the speed of the airflow passing through the device.

[0221] In the described embodiment, the heater (201) is an electric resistance track or tracks deposited on a ceramic substrate. The ceramic substrate is in the form of a blade and is inserted into an aerosol-forming substrate (210) when in use. The heater forms part of the device and can be used to heat many different substrates. However, the heater may be a replaceable component, and the replacement heater may have different electric resistances.

[0222] The type of system described in Fig. 8 may be a continuous heating system in which the temperature of the heater is maintained at a target temperature while the system is turned on, or a puffing operating system in which the temperature of the heater is raised by supplying more power during the period when puffing is detected.

[0223] In the case of a puffing operating system, the operation is very similar to that described with reference to the previous embodiment. When the substrate is dried near the heater, the heater resistance will rise faster for a given applied power than when the substrate still contains an aerosol-forming agent that can be vaporized at a relatively low temperature.

[0224] In the case of a continuous heating system, there will be an initial temperature drop of the heater when puffing is used on the system due to the cooling effect of the airflow passing through the heater. The heater resistance can be measured when puffing is first detected and recorded as R1, and the subsequent resistance R2 when the system returns the heater to the target temperature can be measured during the period Δt1 after puffing detection in a manner similar to that described above. ΔR can be calculated as described above and can be compared to a stored threshold value as described above to determine whether the substrate is dry near the heater. The substrate may be dry because it has been depleted through use, is old, has been improperly stored, or is a counterfeit and has a different moisture content from the genuine aerosol-forming substrate.

[0225] The system of Fig. 8 includes a warning LED (215) within an electrical circuit (209) that is illuminated when a negative condition is detected.

[0226] FIG. 9 is a flowchart illustrating a method for detecting an unauthorized, damaged, or incompatible heater. In the first step (300), the insertion of a cartridge containing a heater into the device is detected. Then, the electrical resistance R of the heater 1refThis is measured at this step (300). This occurs for a predetermined period, e.g., 100 ms, after power is supplied to the heater. At step (320), the measured resistance R1 is compared to a range of expected or acceptable resistances. The acceptable resistance range takes into account manufacturing tolerances and deviations between the genuine heater and the substrate. If R1 is outside the expected range, the process proceeds to step (330), where an indication such as an audible alarm is provided, and power is cut off to the heater because it is considered incompatible with the device. Afterward, the process returns to step (300) to wait for the insertion of a new cartridge.

[0227] Initial resistance R in step (300) 1ref As an alternative to or in addition to the measurement, the initial resistance change rate may be measured within a predetermined time, e.g., 100 ms, after power is supplied to the heater. This may be done by taking multiple resistance measurements at different times during a predetermined period and then calculating the initial resistance change rate from the multiple resistance measurements and the time at which these measurements were taken. In the same way that a specific design of the heater is expected to have an initial resistance within a range of acceptable values, a specific design of the heater may be expected to have an initial resistance change rate for a given applied power within a range of acceptable rates of change of resistance values. The calculated initial resistance change rate may be compared with an acceptable range of rates of change of resistance values, and if the calculated resistance change rate is outside the acceptable range, the process proceeds to step (330).

[0228] R in step (320) 1refIf it is determined that the resistance is within the expected range, the process proceeds to step (340). In step (340), power is applied to the heater for a period Δt1, after which the difference ΔR is calculated. Advantageously, Δt1 is selected to be a short period before significant aerosol generation. In step (350), the value of ΔR is compared to a range of expected or acceptable values. The range of expected values ​​takes into account deviations during the manufacture of the heater and substrate assembly. If the value of ΔR is outside the expected range, the heater is considered incompatible, and the process proceeds to step (330) as described above and then returns to step (300). If the value of ΔR is within the expected range, the process proceeds to step (360), where power is supplied to the heater to allow aerosol generation when requested by the user.

[0229] Although the present invention has been described with reference to three different types of electric heating aerosol generating systems, it should be apparent that it is applicable to other electric heating aerosol generating systems.

[0230] Furthermore, it should be apparent that the present invention may be implemented as a computer program product for execution in a programmable controller within an existing aerosol generation system. The computer program product may be provided as downloadable software or on a computer-readable medium such as a compact disc.

[0231] The exemplary embodiments described above are exemplary but not limiting. Considering the exemplary embodiments discussed above, other embodiments consistent with said exemplary embodiments will now become apparent to those skilled in the art.

Claims

Claim 1 An aerosol generating system comprising: a main body configured to accommodate an aerosol forming substrate; a cartridge including a heater, wherein the cartridge is configured to be coupled with the main body; the heater configured to heat the aerosol forming substrate; a power source configured to supply current to the heater; and an electrical circuit connected to the heater and the power source, wherein the electrical circuit includes a memory, and the electrical circuit is configured to detect coupling of the cartridge to the main body, determine an initial resistance of the heater and a subsequent resistance of the heater in response to the detection of coupling of the cartridge to the main body, and determine the presence of a negative condition based on a change in the resistance of the heater compared with a threshold value stored in the memory, wherein the change in the resistance of the heater is based on the determined initial resistance and the subsequent resistance, and the threshold value includes a low threshold value and a high threshold value. Claim 2 An aerosol generating system according to claim 1, further comprising an aerosol generating device, wherein the aerosol generating device comprises the main body, the power source, and the electrical circuit. Claim 3 In paragraph 2, the aerosol generating system is further configured such that the cartridge is inserted into the aerosol generating device and holds the aerosol forming substrate. Claim 4 In paragraph 3, the aerosol generating system is configured such that the aerosol generating device and the cartridge are detachable from the aerosol generating device after the cartridge is inserted. Claim 5 In paragraph 3, the aerosol generating system comprises a cartridge configured to deliver the aerosol forming substrate to the heater. Claim 6 In paragraph 5, the above-mentioned capillary material comprises a first material and a second material, an aerosol generating system. Claim 7 In paragraph 6, the first material is an aerosol generating system located between the heater and the second material. Claim 8 In claim 6, the aerosol generating system wherein the first material has a higher thermal decomposition temperature than the second material. Claim 9 In claim 6, the aerosol generating system is configured such that the second material holds more liquid per unit volume than the first material. Claim 10 In paragraph 2, the aerosol generating device further comprises a puff detector configured to detect a puff, the power supply configured to supply current to the heater when a puff is detected by the puff detector, and the electric circuit configured to detect the presence of the negative condition during the puff, an aerosol generating system. Claim 11 In claim 1, the aerosol generating system, wherein the heater comprises a plurality of filaments. Claim 12 In claim 11, the aerosol generating system wherein the plurality of filaments are in the shape of a mesh. Claim 13 In paragraph 12, the above mesh defines gaps configured to exhibit capillary action, an aerosol generating system. Claim 14 An aerosol generating system according to claim 1, wherein the resistance change includes the resistance difference between the initial resistance and the subsequent resistance of the heater. Claim 15 In claim 14, the aerosol generating system is further configured such that the electric circuit measures the initial resistance of the heater before the current is supplied and measures the subsequent resistance after the current is supplied. Claim 16 An aerosol generating system according to claim 14, wherein the electric circuit is further configured to detect the presence of an electrical connection between the electric circuit and the heater, and to measure the initial resistance of the heater after the electrical connection is detected. Claim 17 delete Claim 18 An aerosol generating system according to claim 1, wherein the electric circuit is further configured to provide an indication of the negative condition when the resistance change is higher than the low threshold value and lower than the high threshold value. Claim 19 An aerosol generating system according to claim 1, wherein the electric circuit is further configured to reduce or suppress the current to the heater when the resistance change is higher than the high threshold value. Claim 20 An aerosol generating system according to claim 1, wherein the electric circuit is further configured to store the determinations of the negative conditions in the memory, determine the number of consecutive determinations of the negative conditions, and disable the heater based on the number of consecutive determinations of the negative conditions.

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