Aerosol generating device and system with conductivity sensor

Abstract

An aerosol generating system comprises: a liquid storage portion for holding a liquid aerosol-forming substrate; an atomizer in fluid connection with the liquid storage portion; a conductivity sensor; a power supply; and control electronics. The conductivity sensor comprises at least two electrodes (104, 106) and is arranged to sense the conductivity of the liquid aerosol-forming substrate from the liquid storage portion. The control electronics are configured to: control power from the power supply to the atomizer to atomize the liquid aerosol-forming substrate from the liquid storage portion; and control power from the power supply to the electrodes (104, 106) of the conductivity sensor, the power being provided as an AC voltage to the conductivity sensor. The control electronics are further configured to: receive one or more measurements indicative of the conductivity of the liquid aerosol-forming substrate from the conductivity sensor; and determine a nicotine concentration of the liquid aerosol-forming substrate based on one or more of the measurements from the conductivity sensor.

Description

Technical Field

[0001] The present invention relates to an aerosol-generating system that atomizes an aerosol-forming substrate comprising nicotine to generate an aerosol. In particular, the present invention relates to an aerosol-generating system comprising a conductivity sensor. The present invention also relates to an aerosol-generating device comprising a conductivity sensor and a cartridge comprising the conductivity sensor. Background Art

[0002] Aerosol-generating systems, such as electronic cigarettes, that operate by heating a liquid formulation to generate an aerosol for inhalation by the user are widely used. These systems typically include a liquid storage portion that holds the liquid formulation, a heater for vaporizing the liquid formulation, a wick that transfers the liquid from the liquid storage portion to the heater, a power source, and control electronics. Some of these systems include a refillable liquid storage portion. Some of these systems include a device portion and a replaceable cartridge. In some systems, the device portion includes the power source and control electronics, and the cartridge contains the liquid storage portion that holds the liquid formulation, a heater for vaporizing the liquid formulation, and a wick that transfers the liquid from the liquid storage portion to the heater.

[0003] In a system comprising a refillable liquid storage portion, liquid formulations having different compositions can be introduced into the liquid storage portion, wherein the liquid storage portion is refilled. Similarly, in a system comprising a device portion and a replaceable cartridge, different cartridges can contain liquid formulations having different compositions. Specifically, different liquid formulations can include different amounts or concentrations of nicotine. Thus, an aerosol generated from one particular liquid formulation can contain a different amount or concentration of nicotine than an aerosol generated from a different liquid formulation. Summary of the Invention

[0004] It is desirable that an aerosol generating system be able to assess the nicotine concentration of a liquid formulation. It is also desirable that an aerosol generating system be able to control the nicotine concentration of aerosols generated from different liquid formulations. It is also desirable that the manufacture of aerosol generating systems be able to be standardized regardless of the aerosol-forming substrate used with the aerosol generating system.

[0005] According to the present disclosure, an aerosol generating system is provided, comprising: a liquid storage portion for holding a liquid aerosol-forming substrate; an atomizer in fluid connection with the liquid storage portion; a conductivity sensor; a power supply; and control electronics. The conductivity sensor comprises at least two electrodes and is arranged to sense the conductivity of the liquid aerosol-forming substrate from the liquid storage portion. The control electronics is configured to: control power from the power supply to the atomizer to atomize the liquid aerosol-forming substrate from the liquid storage portion; and control power from the power supply to electrodes of the conductivity sensor, the power being provided to the conductivity sensor as an AC voltage. The control electronics is further configured to: receive one or more measurements indicative of the conductivity of the liquid aerosol-forming substrate from the conductivity sensor; and determine a nicotine concentration of the liquid aerosol-forming substrate based on one or more of the measurements from the conductivity sensor.

[0006] A liquid aerosol-forming substrate may comprise three main components, typically nicotine, an aerosol-former, and water. Advantageously, the present inventors have recognized that the conductivity of the liquid aerosol-forming substrate may provide an indication of the nicotine concentration of the liquid aerosol-forming substrate. Specifically, the present inventors have recognized that a manufacturer of an aerosol-generating device may also manufacture or sell proprietary liquid aerosol-forming substrates having different nicotine concentrations and provide the aerosol-generating device with a conductivity sensor that may enable the device to determine which proprietary aerosol-forming substrate has been received in the device based on the conductivity of the aerosol-forming substrate.

[0007] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol. The volatile compounds can be released by heating the aerosol-forming substrate. The volatile compounds can be released by moving the aerosol-forming substrate through the channel of a vibratory element.

[0008] The aerosol-forming substrate is a liquid aerosol-forming substrate. The aerosol-forming substrate may comprise a mixture of a liquid component and a solid component. The aerosol-forming substrate comprises nicotine. Preferably, the aerosol-forming substrate comprises a nicotine salt. 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, which are released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may 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, in use, facilitates the formation of a dense and stable aerosol and is substantially resistant to thermal degradation at the operating temperature of the system. Suitable aerosol formers are well known in the art and include, but are not limited to, polyols such as triethylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols such as glycerol mono-, di-, or triacetate; and fatty acid esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanoic acid. Preferred aerosol formers are polyols or mixtures thereof, for example, triethylene glycol, 1,3-butylene glycol, and most preferably glycerol. The aerosol-forming matrix may include other additives and ingredients, such as fragrances.

[0009] In some preferred embodiments, the nicotine is in the form of a nicotine salt. In some particularly preferred embodiments, the nicotine salt may be the only electrolyte present in the liquid aerosol-forming substrate. In some embodiments, the nicotine electrolyte concentration may be significantly higher than the concentrations of other electrolytes in the liquid aerosol-forming substrate. Thus, the effect of changes in the concentrations of other components of the liquid aerosol-forming substrate on the conductivity of the substrate may be negligible.

[0010] Manufacturers of liquid aerosol-forming substrates can produce different proprietary aerosol-forming substrates with different concentrations of nicotine. In order to change the nicotine concentration in the aerosol-forming substrate, the manufacturer can increase or decrease the amount of nicotine in a given amount of substrate by reducing or increasing the amount of solvent (e.g., water) in the given amount of substrate. For example, a manufacturer can produce a low-nicotine aerosol-forming substrate and a high-nicotine aerosol-forming substrate, wherein the low-nicotine aerosol-forming substrate comprises a first amount of nicotine and a first amount of water for a given amount of substrate, and the high-nicotine aerosol-forming substrate comprises a second amount of nicotine greater than the first amount of nicotine and a second amount of water less than the first amount of water for a given amount of substrate. The low-nicotine aerosol-forming substrate can have a lower nicotine concentration than the high-nicotine aerosol-forming substrate. The low-nicotine aerosol-forming substrate can have a first conductivity, and the high-nicotine aerosol-forming substrate can have a second conductivity greater than the first conductivity. The difference between the first conductivity and the second conductivity can increase as the temperature increases.

[0011] The liquid aerosol-forming substrate may typically have a conductivity of between about 1 microSiemens / cm and about 500 microSiemens / cm at 20 degrees C, and preferably has a conductivity of between about 1 microSiemens / cm and about 400 microSiemens / cm at 20 degrees C. Preferably, the conductivity sensor is adapted to measure the conductivity of the aerosol-forming substrate within these ranges.

[0012] The conductivity sensor may be any suitable type of sensor for sensing the conductivity of the liquid aerosol-forming substrate in the system.

[0013] The conductivity sensor may be positioned at any suitable location in the aerosol generating system. The conductivity sensor may be positioned in the liquid storage portion. The conductivity sensor may be positioned at or around the liquid storage portion. The conductivity sensor may be positioned at or around the nebulizer. The conductivity sensor may be positioned between the liquid storage portion and the nebulizer. In some embodiments, the conductivity sensor is a separate component from the nebulizer. In some preferred embodiments, the nebulizer includes the conductivity sensor. In these preferred embodiments, the nebulizer may include one or more components, and at least one electrode of the conductivity sensor may include a component of the nebulizer.

[0014] The electrodes of the conductivity sensor may have any suitable form. For example, the electrodes may be coil electrodes comprising a plurality of filaments, ring electrodes, or mesh electrodes. In some embodiments, the electrodes may be arranged so as to contact the liquid aerosol-forming substrate. In some embodiments, the electrodes may be arranged so as not to contact the liquid aerosol-forming substrate. In other words, the electrodes may be separate from the liquid aerosol-forming substrate.

[0015] In some first preferred embodiments, the conductivity sensor comprises two electrodes. The conductivity sensors of these first preferred embodiments may be referred to as two-point conductivity sensors.

[0016] The two electrodes can be spaced apart so that a cavity is formed between the electrodes. For example, the two electrodes can be spaced apart by a distance between about 1 mm and about 20 mm. As used herein, the term "cavity" refers to any suitable gap or space between the two electrodes, including a two-dimensional space between two completely flat electrodes arranged in the same plane and a three-dimensional space between the two electrodes. The two electrodes can be arranged so that a liquid aerosol-forming substrate can be disposed in the cavity between the electrodes. Preferably, the two electrodes are arranged to contact the liquid aerosol-forming substrate from the liquid storage portion. The two electrodes can be arranged so that when the liquid aerosol-forming substrate is not disposed in the cavity between the two electrodes, the two electrodes are electrically insulated from each other.

[0017] In these first preferred embodiments, the control electronics may be configured to supply power to the electrodes at an alternating voltage from a power supply.The control electronics may also be configured to receive one or more measurements from the electrodes indicative of the electrical conductivity of the liquid aerosol-forming substrate.

[0018] In these first preferred embodiments, when the liquid aerosol-forming substrate is disposed in a cavity between the electrodes, applying an AC voltage across the two electrodes may cause an AC current to flow between the two electrodes, through the liquid aerosol-forming substrate in the cavity between the electrodes. The control electronics may be configured to measure the current between the two electrodes. The control electronics may be configured to measure the voltage between the two electrodes. One or more of the measured current and voltage may be used to determine the conductivity of the liquid aerosol-forming substrate disposed in the cavity between the two electrodes.

[0019] In these first preferred embodiments, the control electronics may be configured to supply an alternating voltage to the conductivity sensor at a frequency between about 1 kHz and about 500 kHz.

[0020] In some second preferred embodiments, the conductivity sensor comprises four electrodes. The conductivity sensors of these second preferred embodiments may be referred to as four-point conductivity sensors.

[0021] The conductivity sensor may include two inner electrodes and two outer electrodes. The two outer electrodes may be spaced apart to form an outer cavity between the two outer electrodes. For example, the two outer electrodes may be spaced apart by a distance between about 5 mm and about 20 mm. The two inner electrodes may be spaced apart to form an inner cavity between the two inner electrodes. For example, the two inner electrodes may be spaced apart by a distance between about 5 mm and about 20 mm. In some embodiments, the two inner electrodes are disposed in the outer cavity between the two outer electrodes. In these embodiments, the two inner electrodes may be spaced apart by a distance between about 1 mm and about 18 mm.

[0022] The two outer electrodes may be arranged such that the liquid aerosol-forming substrate may be provided in the outer cavity between the two outer electrodes.The two outer electrodes may be arranged such that the two outer electrodes are electrically insulated from each other when the liquid aerosol-forming substrate is not provided in the outer cavity between the outer electrodes.

[0023] The two inner electrodes may be arranged such that the liquid aerosol-forming substrate may be disposed in the inner cavity between the two inner electrodes. The two inner electrodes may be arranged such that when the liquid aerosol-forming substrate is not disposed in the inner cavity between the two inner electrodes, the two inner electrodes are electrically insulated from each other. The two inner electrodes may also be arranged such that when the liquid aerosol-forming substrate is not disposed in the inner cavity between the two inner electrodes, the two inner electrodes are electrically insulated from the two outer electrodes.

[0024] Preferably, the two outer electrodes and the two inner electrodes are arranged to be in contact with the liquid aerosol-forming substrate from the liquid storage portion.

[0025] In these second preferred embodiments, the control electronics may be configured to supply power to the outer electrode at an AC voltage from a power supply. The control electronics may be configured to receive one or more measurements indicative of the electrical conductivity of the liquid aerosol-forming substrate from the outer electrode. The control electronics may be configured to receive one or more measurements indicative of the electrical conductivity of the liquid aerosol-forming substrate from the inner electrode.

[0026] In these second preferred embodiments, when the liquid aerosol-forming substrate is disposed in the outer cavity between two outer electrodes, applying an AC voltage to the two outer electrodes can cause an AC current to flow between the two outer electrodes, through the liquid aerosol-forming substrate disposed in the outer cavity. When the liquid aerosol-forming substrate is disposed in the outer cavity, the liquid aerosol-forming substrate is also disposed in the inner cavity between the two inner electrodes. When the AC current flows between the two outer electrodes, it also flows between the two inner electrodes, thereby establishing an AC voltage across the two inner electrodes.

[0027] The control electronics may be configured to measure a voltage drop between the two inner electrodes. The measured voltage drop between the two inner electrodes may be used to determine the conductivity of the liquid aerosol-forming substrate disposed in the inner cavity between the two inner electrodes. The control electronics may be configured to measure a current between the two outer electrodes. The measured current between the two outer electrodes may be used to determine the conductivity of the liquid aerosol-forming substrate disposed in the outer cavity. In some particularly preferred embodiments, the control electronics are configured to determine the conductivity of the liquid aerosol-forming substrate using the measured voltage drop between the two inner electrodes and the measured current between the two outer electrodes. The conductivity of the liquid aerosol-forming substrate may be proportional to the applied current.

[0028] Advantageously, a four-point conductivity sensor can minimize the effects of parasitic resistance on voltage measurements made by the conductivity sensor. Parasitic resistance in a conductivity sensor (e.g., contact resistance between leads contacting electrodes) can cause errors in voltage measurements. Advantageously, the four-electrode arrangement of the second preferred embodiment enables voltage measurement to be separated from current measurement. Separating voltage measurement from current measurement can minimize the effects of parasitic resistance on voltage measurements.

[0029] In the four-point conductivity sensor of the second preferred embodiment, the inner electrodes are arranged so that the current between the inner electrodes is substantially the same as the current driven between the outer electrodes. If the voltage across the inner electrodes is measured to have a high impedance, a negligible current can be drawn through the leads connected to the inner electrodes compared to the current between the inner electrodes. Because the current through the leads connected to the inner electrodes is negligible compared to the current across the inner electrodes, the voltage drop across the leads connected to the inner electrodes due to parasitic resistance is negligible compared to the voltage drop across the inner electrodes. Consequently, the voltage measurement across the inner electrodes can include minimal or negligible contribution from the parasitic resistance.

[0030] Additionally, since the measurement of the voltage across the two inner electrodes draws negligible current, the polarisation of the liquid aerosol-forming substrate at the two inner electrodes is also negligible, minimising the effect of polarisation on the voltage measurement in the four-electrode arrangement of the second preferred embodiment.

[0031] In these second preferred embodiments, the control electronics may be configured to supply an alternating voltage to the conductivity sensor at a frequency between about 1 kHz and about 500 kHz.

[0032] In some of these second preferred embodiments, the two inner electrodes may be susceptor elements. As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is located in an alternating electromagnetic field, the susceptor is heated. The heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. Therefore, applying an AC voltage to the two outer electrodes to heat the outer electrodes may induce current in the two inner electrodes. The current induced in the two inner electrodes may be sufficient to heat the two inner electrodes.

[0033] The susceptor element may comprise any suitable material. The susceptor element may be formed from any material capable of being inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for the elongated susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and metal composites. Preferably, the susceptor element comprises metal or carbon. Advantageously, the susceptor element may comprise or be composed of a ferromagnetic material, such as ferritic iron, ferromagnetic alloys (e.g., ferromagnetic steel or stainless steel), ferromagnetic particles, and ferrites.

[0034] In some third preferred embodiments, the conductivity sensor includes two electrodes, namely a first electrode and a second electrode. Preferably, each electrode forms a coil. The first electrode is arranged to induce a current in the second electrode when an AC voltage is supplied to the first electrode. The two electrodes may be spaced apart such that a cavity is formed between the electrodes. The two electrodes may be arranged such that the two electrodes are electrically insulated from each other.

[0035] Where the first electrode and the second electrode form a coil, the first electrode coil may be wound around the first inner cavity. The second electrode coil may be wound around the second inner cavity. The first electrode and the second electrode may be arranged such that the first inner cavity is aligned with the second inner cavity. The first inner cavity and the second inner cavity may define an inner cavity. The inner cavity may define a passage through which the liquid aerosol-forming substrate may flow.

[0036] The conductivity sensors of these third preferred embodiments may be referred to as inductive conductivity sensors.

[0037] In these third preferred embodiments, the control electronics may be configured to supply an alternating voltage to the first electrode.The control electronics may further be configured to receive one or more measurements indicative of the electrical conductivity of the liquid aerosol-forming substrate from the second electrode.

[0038] In these third preferred embodiments, when a liquid aerosol-forming substrate is disposed in the inner cavity between a first electrode and a second electrode, application of an alternating voltage to the first electrode may generate an alternating current in the second electrode by induction. The alternating voltage applied to the first electrode generates a fluctuating magnetic field that causes a current to flow through the liquid aerosol-forming substrate disposed in the inner cavity. The amplitude and direction of the current flowing through the liquid aerosol-forming substrate disposed in the inner cavity affect the alternating current generated in the second electrode. The control electronics may be configured to measure the current or voltage induced in the second electrode. The measured current or voltage may be used to determine the electrical conductivity of the liquid aerosol-forming substrate disposed in the inner cavity between the first electrode and the second electrode. The current induced in the second electrode may be proportional to the electrical conductivity of the liquid aerosol-forming substrate.

[0039] In these third preferred embodiments, the first electrode and the second electrode may be shielded or isolated from the aerosol-forming matrix. In other words, the first electrode and the second electrode may be arranged such that the first electrode and the second electrode are not in contact with the liquid aerosol-forming matrix. The first electrode and the second electrode may be arranged in a conductivity sensor housing. The conductivity sensor housing may define an inner cavity, including a first inner cavity and a second inner cavity. The conductivity sensor housing may be made of any suitable material. The conductivity sensor housing may be made of a material that is substantially impermeable to the liquid aerosol-forming matrix. The conductivity sensor housing may be made of an electrically insulating material. For example, suitable electrically insulating materials include glass, plastic, and ceramic materials. As used herein, an electrically insulating material refers to a material having a conductivity greater than about 1 x 10 at 20°C. 6 Ωm, usually around 1x 10 9 Ωm is about 1x 10 21 Materials with a volume resistivity between Ωm.

[0040] The inductive conductivity sensor may be arranged at any suitable location in the aerosol generating system. Preferably, the inductive conductivity sensor is arranged in the liquid storage portion. Preferably, the inductive conductivity sensor is arranged in the liquid storage portion, and the liquid aerosol-forming substrate contained in the liquid storage portion is able to flow through the lumen between the first electrode and the second electrode.

[0041] In these third preferred embodiments, the control electronics may be configured to supply an alternating voltage to the conductivity sensor at a frequency between about 1 MHz and about 100 MHz.

[0042] In these third preferred embodiments, the first electrode coil may have any suitable number of turns. The second electrode coil may have any suitable number of turns. Preferably, the second electrode coil has the same number of turns as the first electrode coil. The first electrode coil may have any suitable form. For example, the first electrode coil may be a spiral coil or a toroidal coil. The second electrode coil may have any suitable form. For example, the second electrode coil may be a spiral coil or a toroidal coil. Preferably, the second electrode coil has the same form as the first electrode coil. Particularly preferably, the first electrode coil and the second electrode coil comprise identical toroidal coils.

[0043] The control electronics controls the supply of power from the power supply to the electrodes of the conductivity sensor. The power supplied to the conductivity sensor is provided as an alternating voltage. The alternating voltage may be supplied to the electrodes of the conductivity sensor at any suitable frequency.

[0044] The control electronics are configured to determine the nicotine concentration of the liquid aerosol-forming substrate based on one or more of the measurements from the conductivity sensor. The control electronics may be configured to determine the nicotine concentration in any suitable manner. In one example, the predetermined functional relationship between conductivity and nicotine concentration may be known. An appropriate algorithm may be stored in a memory of the control electronics, and the control electronics may be configured to calculate the nicotine concentration by applying the measured values ​​of conductivity to the stored algorithm. In another example, predetermined conductivity values ​​of aerosol-forming substrates of known nicotine concentrations may be stored in a lookup table in the memory of the control electronics, and the measured values ​​of conductivity may be compared to the stored values ​​of conductivity to determine the nicotine concentration of the aerosol-forming substrate. The predetermined conductivity values ​​of aerosol-forming substrates of known nicotine concentrations may be determined by calibration, typically performed at the factory before the aerosol generating system is provided to a user for use.

[0045] It should be understood that determining an indication of the nicotine concentration in the liquid aerosol-forming substrate may not necessarily involve calculating a nicotine concentration value, or storing a nicotine concentration value in a lookup table stored in a memory of the control electronics. For example, in some embodiments according to the present invention, determining the nicotine concentration in the liquid aerosol-forming substrate includes using a conductivity measurement to determine a specific power to supply to the atomizer. In these embodiments, using the conductivity measurement to determine the power to supply to the atomizer is based on a predetermined relationship between the nicotine concentration of the liquid aerosol-forming substrate and the conductivity.

[0046] In some embodiments, the control electronics are further configured to control the supply of power from the power source to the atomizer to aerosolize the liquid aerosol-forming substrate based on the determined nicotine concentration of the liquid aerosol-forming substrate. Advantageously, this may enable the aerosol-generating system to control the amount of aerosol generated by the system based on the nicotine concentration of the aerosol-forming substrate.

[0047] Preferably, the control electronics are configured to control the power supplied from the power source to the atomizer based on the determined nicotine concentration of the liquid aerosol-forming substrate, by comparing the determined nicotine concentration with a predetermined threshold, to atomize the liquid aerosol-forming substrate. The control electronics may also be configured to supply a first power to the atomizer when the determined nicotine concentration is equal to or below the predetermined threshold. The control electronics may also be configured to supply a second power, lower than the first power, to the atomizer when the determined nicotine concentration exceeds the predetermined threshold. This configuration may allow a relatively large amount of aerosol to be generated during a user experience when the determined nicotine concentration is relatively low, and may allow a relatively small amount of aerosol to be generated when the determined nicotine concentration is relatively high. Varying the amount of aerosol generated during a user experience may vary the amount of nicotine delivered to the user during the user experience. Advantageously, this may enable the aerosol-generating system to deliver a consistent amount of nicotine to the user during the user experience, regardless of the nicotine concentration of the liquid aerosol-forming substrate.

[0048] The control electronics may be configured to control the power supplied from the power supply to the atomizer in discrete increments. For example, a plurality of discrete power settings may be stored in a lookup table in a memory of the control electronics, each power setting associated with a specific predetermined nicotine concentration and conductivity. The control electronics may be configured to compare the conductivity measurement value with the conductivity values ​​stored in the lookup table and apply power from the power supply to the atomizer based on the power setting associated with the stored conductivity value that matches the conductivity measurement value.

[0049] The control electronics may be configured to control the power supplied continuously from the power supply to the atomizer. The control electronics may be configured to control the power supplied from the power supply to the atomizer based on conductivity. A predetermined algorithm may be stored in a memory of the control electronics, and the conductivity measurement may be applied to the predetermined algorithm to determine the power to be supplied from the power supply to the atomizer.

[0050] The control electronics may be configured to supply power from the power supply to the electrodes of the conductivity sensor at any suitable time. Preferably, the control electronics are configured to supply power from the power supply to the electrodes of the conductivity sensor before supplying power from the power supply to the atomizer to atomize the liquid aerosol-forming substrate. Advantageously, this may enable the control electronics to control the power supplied from the power supply to the atomizer based on the determined nicotine concentration of the liquid aerosol-forming substrate.

[0051] The electrical conductivity of a liquid aerosol-forming substrate may vary depending on the temperature of the aerosol-forming substrate.

[0052] In some embodiments, the aerosol generating device may include a temperature sensor. The control electronics may be configured to receive one or more temperature measurements from the temperature sensor. The control electronics may also be configured to adjust the determination of the nicotine concentration based on one or more of the temperature measurements from the temperature sensor.

[0053] The temperature sensor may be any suitable type of temperature sensor for sensing the temperature of the liquid aerosol-forming substrate. Suitable types of temperature sensors include thermocouples, thermistors and resistance temperature sensors, among others.

[0054] The temperature sensor may be arranged to sense the temperature of the liquid aerosol-forming substrate. The temperature sensor may be arranged at any suitable location relative to the conductivity sensor. Preferably, the temperature sensor is arranged at or around the conductivity sensor to minimize the temperature difference between the liquid aerosol-forming substrate sensed by the temperature sensor and the liquid aerosol-forming substrate sensed by the conductivity sensor. The temperature sensor may be arranged in the liquid storage portion. The temperature sensor may be arranged at or around the atomizer. The temperature sensor may be arranged between the liquid storage portion and the atomizer. In some embodiments, the temperature sensor is a separate component from the atomizer. In some embodiments, the atomizer includes the temperature sensor.

[0055] The control electronics may adjust the determination of nicotine concentration in any suitable manner based on the temperature measurement.

[0056] In one example, the predetermined functional relationship between temperature and conductivity is known. An algorithm may be stored in a memory of the control electronics, and the control electronics may be configured to calculate the nicotine concentration by applying the measurements of conductivity and temperature to the stored algorithm.

[0057] In another example, predetermined aerosol-forming substrate conductivity values ​​for known nicotine concentrations at specific temperatures may be stored in a look-up table in the memory of the control electronics, and measured values ​​of conductivity and temperature may be compared to the stored values ​​of conductivity and temperature to determine the nicotine concentration of the aerosol-forming substrate.

[0058] In some embodiments, the aerosol generating system may include a heater. The heater may be arranged to heat the liquid aerosol-forming substrate from the liquid storage portion. The heater may be configured to heat the liquid aerosol-forming substrate to a predetermined temperature. The power supply may be configured to supply power to the heater. The control electronics may be configured to supply power from the power supply to the heater to heat the liquid aerosol-forming substrate from the liquid storage portion to the predetermined temperature.

[0059] The heater may be arranged at any suitable location relative to the conductivity sensor. Preferably, the heater is arranged at or around the conductivity sensor to minimize the temperature difference between the liquid aerosol-forming substrate heated by the heater and the liquid aerosol-forming substrate sensed by the conductivity sensor. The heater may be arranged in the liquid storage portion. The heater may be arranged at or around the atomizer. The heater may be arranged between the liquid storage portion and the atomizer. Typically, the heater is arranged upstream of the conductivity sensor so that the heater can heat the liquid aerosol-forming substrate to a predetermined temperature before the liquid aerosol-forming substrate reaches the conductivity sensor. In some embodiments, the heater is a component separate from the atomizer. In some embodiments, the atomizer includes the heater.

[0060] The control electronics may be configured to supply power from the power supply to the heater at any suitable time. In some embodiments, the control electronics is configured to supply power from the power supply to the heater continuously to maintain the temperature of the liquid aerosol-forming substrate at a predetermined temperature. In some embodiments, the control electronics is configured to supply power from the power supply to the heater for a predetermined period of time before a conductivity measurement is taken to ensure that the liquid aerosol-forming substrate has sufficient time to reach the predetermined temperature before a conductivity measurement is taken.

[0061] The predetermined temperature may be any suitable temperature. Typically, the predetermined temperature is above the expected ambient temperature so that the ambient temperature does not affect the temperature of the liquid aerosol-forming substrate at the conductivity sensor. For example, the predetermined temperature may be at least about 60 degrees Celsius, at least about 70 degrees Celsius, or at least about 80 degrees Celsius. The predetermined temperature is below the boiling point of the liquid aerosol-forming substrate.

[0062] In embodiments comprising a heater for heating the aerosol-forming substrate to a predetermined temperature, it may not be necessary to provide a temperature sensor for sensing the temperature of the liquid aerosol-forming substrate, as it can be reasonably assumed that the temperature of the liquid aerosol-forming substrate sensed by the conductivity sensor is at the predetermined temperature.

[0063] The aerosol generating system may include a housing. The housing may be formed from any suitable material or combination of materials. Suitable materials include, but are not limited to, aluminum, polyetheretherketone (PEEK), polyimide (e.g. ), polyethylene terephthalate (PET), polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), epoxy resin, polyurethane resin, vinyl resin, liquid crystal polymer (LCP) and modified LCP such as LCP with graphite or glass fiber.

[0064] The housing may define a liquid storage portion. The liquid storage portion may be any suitable shape and size for holding sufficient liquid aerosol-forming substrate for multiple user experiences. For example, the liquid storage portion may have a sufficient capacity to allow continuous aerosol generation for a period of approximately six minutes, or for a multiple of six minutes. In another example, the liquid storage portion may have a capacity sufficient to allow a predetermined number of puffs or discontinuous activation of the nebulizer.

[0065] In some embodiments, a porous carrier material may be disposed within the liquid storage portion. The liquid aerosol-forming substrate may be adsorbed or otherwise loaded onto the porous carrier material. The porous carrier material may be formed from any suitable adsorbent plug or body. For example, a suitable adsorbent plug or body may be a foamed metal or plastic material, polypropylene, polyester, nylon fiber, or ceramic.

[0066] The aerosol generating system may further comprise a liquid transport element. The liquid transport element may be configured such that, in use, the liquid aerosol-forming substrate is transported from the liquid storage portion to the atomizer along the liquid transport element by capillary action. In embodiments where the liquid storage portion comprises a porous carrier material, the liquid transport element is configured to transport the liquid aerosol-forming substrate from the porous carrier material to the atomizer. The liquid transport element may comprise a capillary material. A capillary material is a material that actively transports liquid from one end of the material to the other end. The capillary material may advantageously be oriented in the liquid storage portion to transport the liquid aerosol-forming substrate to the atomizer.

[0067] The liquid transport element may comprise any suitable material or combination of materials capable of transporting the liquid aerosol-forming substrate along its length. The liquid transport element may be formed from a porous material, but need not be so. The liquid transport element may be formed from a material having a fibrous or sponge-like structure. The liquid transport element preferably comprises a bundle of capillaries. For example, the liquid transport element may comprise a plurality of fibers or filaments, or other fine-pored tubes. The liquid transport element may comprise a sponge-like or foam-like material. Preferably, the structure of the liquid transport element forms a plurality of pores or tubes through which the liquid aerosol-forming substrate may be transported by capillary action. Particularly preferred materials will depend on the physical properties of the liquid aerosol-forming substrate. The example of suitable capillary material comprises sponge or foam material, ceramic or graphite-based material in the form of fiber or sintered powder, foam metal or plastic material, for example, fibrous material made by spinning or extruding fiber, for example cellulose acetate, polyester or bonding polyolefin, polyethylene, terylene or polypropylene fiber, nylon fiber, ceramic, glass fiber, silica glass fiber, carbon fiber, for example metal fiber of medical grade stainless steel alloys such as austenitic 316 stainless steel and martensitic 440 and 420 stainless steel. The liquid transport element can have any suitable capillary property, so that it can be used together with different liquid physical properties. The liquid aerosol forms a matrix with physical properties, including but not limited to viscosity, surface tension, density, thermal conductivity, boiling point and vapor pressure, which allows the liquid aerosol to form a matrix and be transported via the liquid transport element. The liquid transport element can be formed by heat-resistant material. The liquid transport element can comprise a plurality of fiber strands. The plurality of fiber strands can be aligned substantially along the length of the liquid transport element.

[0068] In embodiments wherein the liquid storage section comprises a porous carrier material, the porous carrier material and the liquid transport element may comprise the same material.Preferably, the porous carrier material and the liquid transport element comprise different materials.

[0069] The nebulizer can be any suitable type of nebulizer. For example, the nebulizer can be a sonic nebulizer. By using vibrations, typically at ultrasonic frequencies, a sonic nebulizer can move an aerosol-forming substrate through a plurality of nozzles to release volatile compounds from the aerosol-forming substrate. In another example, the nebulizer can be a thermal nebulizer. A thermal nebulizer can release volatile compounds from the aerosol-forming substrate by heating the aerosol-forming substrate.

[0070] In some embodiments, the nebulizer includes a conductivity sensor. In these embodiments, the nebulizer may include one or more conductive elements. One or more electrodes of the conductivity sensor may include one or more conductive elements of the nebulizer. Advantageously, combining the nebulizer and conductivity sensor can reduce the number of components of the aerosol generating system, thereby reducing manufacturing cost and complexity.

[0071] In some preferred embodiments, the atomizer is a thermal atomizer. The thermal atomizer may be an electric heater. The thermal atomizer may include one or more heating elements. Preferably, the thermal atomizer includes multiple heating elements.

[0072] In some particularly preferred embodiments, the atomizer is a thermal atomizer comprising a plurality of heating elements, and each electrode of the conductivity sensor comprises a heating element of the thermal atomizer. In these particularly preferred embodiments, the control electronics may further be configured to supply a first power from the power supply to the electrodes of the conductivity sensor to measure the conductivity of the liquid aerosol-forming substrate; and to supply a second power from the power supply to the plurality of heating elements of the atomizer to atomize the liquid aerosol-forming substrate. The second power is greater than the first power. The first power may be sufficient to enable the control electronics to receive a conductivity measurement from the conductivity sensor without raising the temperature of the heating elements to a temperature sufficient to release volatile compounds from the liquid aerosol-forming substrate. The second power may be sufficient to raise the temperature of the heating elements to a temperature sufficient to release volatile compounds from the liquid aerosol-forming substrate.

[0073] The thermal atomizer may include a resistive heating coil. The thermal atomizer may include a plurality of resistive heating coils.

[0074] The thermal atomizer may include a resistive heating grid. The thermal atomizer may include a plurality of resistive heating grids.

[0075] The resistive heating mesh can include a plurality of conductive filaments. The conductive filaments can be substantially flat. As used herein, "substantially flat" means formed in a single plane and not coiled or otherwise conformed to a curved or other non-planar shape. A flat heating mesh can be easier to handle during manufacturing and provide a robust construction.

[0076] The electrically conductive filaments may define spaces between the filaments, and the spaces may have a width of between about 10 micrometers and about 100 micrometers. Preferably, the filaments create capillary action in the spaces so that, in use, the liquid aerosol-forming substrate is drawn into the spaces, thereby increasing the contact area between the heater assembly and the liquid.

[0077] The conductive filaments can form a mesh having a size between about 160 US mesh and about 600 US mesh (+ / - 10%) (i.e., between about 160 and about 600 filaments per inch (+ / - 10%)). The width of the gaps is preferably between about 75 microns and about 25 microns. The percentage of open area of ​​the mesh, that is, the ratio of the area of ​​the gaps to the total area of ​​the mesh, is preferably between about 25% and about 56%. Different types of braided or mesh structures can be used to form the mesh. The conductive filaments can be an array of filaments arranged parallel to each other.

[0078] The conductive filaments may have a diameter between about 8 microns and about 100 microns, preferably between about 8 microns and about 50 microns, and more preferably between about 8 microns and about 39 microns.

[0079] The resistive heating grid can cover an area less than or equal to about 25 square millimeters. The resistive heating grid can be rectangular. The resistive heating grid can be square. The resistive heating grid can have dimensions of about 5 millimeters by about 2 millimeters.

[0080] The conductive filaments may comprise any suitable conductive material. Suitable materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made from ceramic and metallic materials. Such composite materials may comprise doped 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-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, and iron-containing alloys; as well as superalloys based on nickel, iron, cobalt, stainless steel, Alloys based on iron and aluminum and alloys based on iron, manganese and aluminum. is a registered trademark of Titanium Metals Corporation. The filaments may be coated with one or more insulators. Preferred materials for the conductive filaments are 304, 316, 304L and 316L stainless steels, and graphite.

[0081] The resistance of the resistive heating grid is preferably between about 0.3 and about 4 ohms. More preferably, the resistance of the grid is between about 0.5 and about 3 ohms, and more preferably about 1 ohm.

[0082] In embodiments where the thermal atomizer includes a resistive heating coil, the spacing of the coils is preferably between about 0.5 mm and about 1.5 mm, and most preferably about 1.5 mm. The spacing of the coils refers to the spacing between adjacent coil turns. The coil may include fewer than six turns, and preferably has fewer than five turns. The coil may be formed from a resistive wire having a diameter between about 0.10 mm and about 0.15 mm, and preferably about 0.125 mm. The resistive wire is preferably formed from 904 or 301 stainless steel. Examples of other suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of other suitable metal alloys include constantan, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, and iron-containing alloys, as well as superalloys based on nickel, iron, cobalt, stainless steel, Alloys based on iron and aluminum and alloys based on iron, manganese and aluminum.The resistance heating coil may also comprise a metal foil, such as aluminum foil, provided in the form of a ribbon.

[0083] In embodiments where the thermal atomizer includes a resistive heating coil, the resistive heating coil may be wrapped around the liquid delivery material.

[0084] The power source may comprise any suitable type of power source. For example, the power source may comprise a battery. The power source may comprise a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery, such as a lithium cobalt battery, a lithium iron phosphate battery, or a lithium polymer battery. The power source may comprise another form of charge storage device, such as a capacitor. The power source may require recharging. The power source may have a capacity that allows sufficient energy to be stored to be used by the aerosol generating system over multiple use experiences. For example, the power source may have sufficient capacity to allow continuous aerosol generation for a period of approximately six minutes or an integral multiple of six minutes. In another example, the power source may have a capacity sufficient to allow a predetermined number of puffs or discontinuous activation of the nebulizer.

[0085] The control electronics may include a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit (ASIC), or other electronic circuitry capable of providing control. The control electronics may include additional electronic components. The control electronics are configured to regulate power to the heater assembly. Power may be supplied to the heater assembly continuously after system startup, or may be supplied intermittently, such as on a puff-by-puff basis. Power may be supplied to the heater assembly in the form of current pulses.

[0086] The control electronics may advantageously comprise a DC / AC inverter, which may comprise a power amplifier of class D or class E. The DC / AC inverter may enable the control electronics to supply an alternating voltage from the power supply to the conductivity sensor.

[0087] The conductivity sensor may be arranged at any suitable location in the aerosol generating system.

[0088] In some embodiments, the conductivity sensor is arranged in the liquid storage portion. Specifically, an inductive conductivity sensor can be arranged in the liquid storage portion.

[0089] In some embodiments, the system includes one or more porous carrier materials for holding and optionally transporting the liquid aerosol-forming substrate. Where the system includes a porous carrier material containing the liquid aerosol-forming substrate, one or more electrodes of the conductivity sensor may be arranged at or around the porous carrier material. The one or more electrodes of the conductivity sensor may be arranged in contact with the porous carrier material. The one or more electrodes of the conductivity sensor may be arranged in contact with an end of the porous carrier material.

[0090] In some embodiments, the conductivity sensor is arranged between the liquid storage portion and the nebulizer.In these embodiments, the at least two electrodes of the conductivity sensor may be arranged in or around a flow path of the liquid aerosol-forming substrate extending between the liquid storage portion and the nebulizer.

[0091] In some embodiments, the atomizer can include a conductivity sensor. In other words, at least two electrodes of the conductivity sensor can be included in the atomizer. In some preferred embodiments, the atomizer includes multiple elements, such as a heating element, and at least one of the at least two electrodes of the conductivity sensor can include an element of the atomizer. In some embodiments, each electrode of the conductivity sensor includes an element of the atomizer.

[0092] In embodiments where the nebulizer includes a conductivity sensor, the control electronics may be connected to the nebulizer and the conductivity sensor in any suitable manner. The control electronics may include an aerosol generation circuit and a conductivity measurement circuit. The aerosol generation circuit may control power to components of the nebulizer to aerosolize the liquid aerosol-forming substrate. The conductivity measurement circuit may control power to electrodes of the conductivity sensor to measure the conductivity of the liquid aerosol-forming substrate.

[0093] In some embodiments, the control electronics include separate aerosol generation circuitry and conductivity measurement circuitry. In these embodiments, each element of the atomizer that is also configured as an electrode of the conductivity sensor may include at least one electrical contact electrically connecting the element to the aerosol generation circuitry and at least one electrical contact electrically connecting the element to the conductivity measurement circuitry. Preferably, each element of the atomizer that is also configured as an electrode of the conductivity sensor includes two electrical contacts electrically connecting the element to the aerosol generation circuitry and one electrical contact electrically connecting the element to the conductivity measurement circuitry.

[0094] In some embodiments, the control electronics include a shared aerosol generation circuit and a shared conductivity measurement circuit. In these embodiments, each element of the atomizer that is also configured as an electrode of the conductivity sensor may include at least one electrical contact electrically connecting the element to the aerosol generation circuit and the conductivity measurement circuit. Preferably, each element of the atomizer that is also configured as an electrode of the conductivity sensor includes two electrical contacts electrically connecting the element to the aerosol generation circuit and the conductivity measurement circuit.

[0095] In some embodiments, the aerosol generating system comprises a device and a cartridge. The cartridge can be removably received in the device. Typically, the cartridge includes a liquid storage portion, and the device includes a power supply and control electronics. In these embodiments, the conductivity sensor can be disposed in the device or in the cartridge. In some embodiments, the nebulizer is disposed in the device. In some preferred embodiments, the nebulizer is disposed in the cartridge.

[0096] According to the present disclosure, there is provided an aerosol generating system as described above, comprising a device portion and a cartridge portion, wherein the cartridge portion is removably received in the device portion. The device portion comprises a power supply and control electronics, and the cartridge portion comprises a liquid storage portion, a nebulizer, and a conductivity sensor.

[0097] Advantageously, providing an aerosol-generating system with a conductivity sensor in the device or in the cartridge may enable manufacturers to standardize cartridge and device manufacturing, regardless of the aerosol-forming substrate to be contained in the liquid storage portion of the cartridge or device. In other words, providing an aerosol-generating system with a conductivity sensor may enable manufacturers to produce identical cartridges and identical devices, regardless of the liquid aerosol-forming substrate to be contained in the liquid storage portion of the cartridge or device. Such standardization may reduce the cost and complexity of manufacturing cartridges and devices.

[0098] In some embodiments, the conductivity sensor is provided in the device. Advantageously, providing the conductivity sensor in the device can reduce the number of components in the cartridge, and in particular can reduce the number of relatively expensive electrical components in the cartridge, thereby reducing the cost and complexity of manufacturing the cartridge.

[0099] In some embodiments, the conductivity sensor is arranged in the barrel. In some preferred embodiments in which the atomizer is a thermal atomizer comprising a plurality of heating elements and each electrode of the conductivity sensor is formed by a heating element of the atomizer, the conductivity sensor can be arranged in the barrel. In these preferred embodiments, the thermal atomizer is arranged in the barrel. Such barrels are commonly referred to as atomizer cartridges (cartomisers). The atomizer cartridges can make it possible to maintain a high level of hygiene in the aerosol generating system because the parts in contact with the aerosol-forming substrate can be replaced regularly, and the user is not exposed to the parts in contact with the aerosol-forming substrate.

[0100] According to the present disclosure, there is provided a cartridge for an aerosol generating system, the cartridge comprising: a liquid storage portion for holding a liquid aerosol-forming substrate; an atomizer fluidically connected to the liquid storage portion; and a conductivity sensor arranged to sense the conductivity of the liquid aerosol-forming substrate from the liquid storage portion.

[0101] In some particularly preferred embodiments, the conductivity sensor of the cartridge includes two electrodes disposed in the liquid storage portion, namely a first electrode and a second electrode, each electrode forming a coil, wherein when an alternating voltage is supplied to the first electrode, the first electrode is arranged to induce a current in the second electrode. In other words, the cartridge may include an inductive conductivity sensor, as described above.

[0102] The cartridge can have a simple design. The cartridge can have a housing that defines a liquid storage portion. The cartridge housing is preferably a rigid housing comprised of a liquid-impermeable material. As used herein, "rigid housing" means a self-supporting housing. The device can also have a housing. Preferably, the device housing is a rigid housing. The cartridge housing and the device housing can be made of the same material. The device can have a cavity for receiving the cartridge.

[0103] Where the cartridge includes an atomizer, the device may include electrical contacts for electrically connecting a power supply and control electronics in the device to the atomizer in the cartridge. Where the cartridge includes a conductivity sensor, the electrical contacts of the device may electrically connect the control electronics and power supply in the device to the conductivity sensor in the cartridge.

[0104] An aerosol-generating system may include a mouthpiece upon which a user can draw to receive aerosol generated by the aerosol-generating system. In some systems comprising a device and a cartridge, the device includes the mouthpiece. In some systems comprising a device and a cartridge, the cartridge includes the mouthpiece. Advantageously, providing a mouthpiece on the cartridge can help maintain a high level of hygiene in the system, as the cartridge can be discarded and replaced more frequently than the device.

[0105] It will be appreciated that features described with reference to one embodiment may also apply to other embodiments. For example, features described with reference to a cartridge may equally apply to an aerosol generating system, and in particular to an aerosol generating system comprising a cartridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0107] Figure 1a shows a schematic diagram of an aerosol generating system comprising an aerosol generating device and a cartridge inserted into the aerosol generating device;

[0108] Figure 1b Shown Figure 1a Schematic diagram of an aerosol generating system, wherein the cartridge is received in an aerosol generating device;

[0109] Figure 2 A schematic diagram showing an end portion of a liquid delivery element of an aerosol generating system according to an embodiment of the present invention, the end portion of the liquid delivery element having an atomizer and a conductivity sensor;

[0110] Figure 3 shows a schematic diagram of an atomizer and a conductivity sensor according to another embodiment of the present invention;

[0111] Figure 4 A schematic diagram showing an end portion of a liquid delivery element of an aerosol generating system according to another embodiment of the present invention, wherein the end portion of the liquid delivery element has an atomizer and a conductivity sensor;

[0112] Figure 5 Shown Figure 4 a schematic diagram of an end portion of a liquid delivery element comprising an atomizer and electrical connections between a conductivity sensor and control electronics of an aerosol generating device;

[0113] Figure 6a 、 6b , 6c and 6d show suitable Figure 4 a schematic diagram of elements of an embodiment of control electronics for use with an atomizer and conductivity sensor;

[0114] Figure 7 shows a schematic diagram of a four-point conductivity sensor according to another embodiment of the present invention;

[0115] Figure 8 Shown Figure 7 Schematic diagram of a first side of a four-point conductivity sensor;

[0116] Figure 9 A schematic diagram showing an inductive conductivity sensor according to another embodiment of the present invention; and

[0117] Figure 10 Shown by Figure 9 Schematic diagram of a cross-section of the length of an inductive conductivity sensor. DETAILED DESCRIPTION

[0118] Figure 1a and 1b is a schematic diagram of an exemplary aerosol generating system comprising a cartridge, in which a conductivity sensor according to embodiments of the present invention may be provided. Figure 1a and 1b They are from international patent application publication number WO 2015 / 117702A1 Figure 1a and 1d.

[0119] Figure 1a is a schematic diagram of an aerosol generating device 10 and a separate cartridge 20 which together form an aerosol generating system.

[0120] The cartridge 20 contains the aerosol-forming substrate and is configured to be received within the device in the cavity 18. When the aerosol-forming substrate provided in the cartridge 20 is exhausted, the cartridge should be replaceable by the user. Figure 1a The cartridge 20 is shown just before insertion into the device, wherein Figure 1a The arrow 1 in the figure indicates the direction of insertion of the cartridge.

[0121] The cartridge 20 comprises a generally cylindrical housing 24 having a size and shape selected to be received in the chamber 18. The housing contains a capillary material (not shown) immersed in a liquid aerosol-forming matrix. In this example, the aerosol-forming matrix comprises 39% by weight of glycerol, 39% by weight of propylene glycol, 20% by weight of water and flavorings, and 2% by weight of nicotine. The capillary material is a material that actively transmits liquid from one end to the other, and can be made of any suitable material. In this example, the capillary material is formed by polyester.

[0122] The housing has an open end to which a heater assembly 30 is secured. The heater assembly 30 includes a substrate having an opening formed therein, a pair of electrical contacts secured to the substrate and separated from each other by a gap, and a plurality of electrically conductive heater filaments spanning the opening and secured to the electrical contacts on opposite sides of the opening.

[0123] The heater assembly 30 is covered by a removable cover 26. The cover comprises a liquid-impermeable plastic sheet that is glued to the heater assembly but can be easily peeled off. Tabs are provided on the sides of the cover to allow the user to grasp the cover while peeling off the tabs. It will now be apparent to one of ordinary skill in the art that while gluing is described as a method of securing the impermeable plastic sheet to the heater assembly, other methods familiar to those skilled 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.

[0124] The aerosol generating device 10 is portable and has a size comparable to a conventional cigar or cigarette. The device 10 comprises a body 11 and a mouthpiece portion 12. The body 11 contains a battery 14 (e.g., a lithium iron phosphate battery), control electronics 16, and a chamber 18. The mouthpiece portion 12 is connected to the body 11 by a hinge connection 21 and can be used in various positions, such as in a conventional cigar or cigarette. Figure 1a The open position shown in Figure 1bThe mouthpiece portion 12 is placed in the open position to allow insertion and removal of the cartridge 20, and is placed in the closed position when the system is to be used to generate an aerosol, as will be described. The mouthpiece portion includes a plurality of air inlets 13 and outlets 15. In use, the user sucks or draws on the outlets to inhale air from the air inlets 13, through the mouthpiece portion to the outlets 15, and then into the user's mouth or lungs. An internal baffle 17 is provided to force air to flow through the cartridge 20 and through the mouthpiece portion 12, as will be described.

[0125] Cavity 18 has a circular cross-section and is sized to receive housing 24 of cartridge 20. Electrical connectors 19 are provided at the sides of cavity 18 to provide electrical connection between control electronics 16 and battery 14 and corresponding electrical contacts on cartridge 20.

[0126] The tube 20 is inserted into the cavity 18 and the cap 26 is removed from the tube. In this position, the electrical connector is placed against the electrical contacts on the tube, as will be described. The mouthpiece portion 12 is then moved to the closed position.

[0127] Figure 1b The system is shown with the mouthpiece portion 12 in a closed position. The mouthpiece portion 12 is held in the closed position by a clip mechanism (not shown).

[0128] The mouthpiece portion 12 in the closed position maintains electrical contact between the cartridge and the electrical connector 19, ensuring a good electrical connection during use, regardless of the orientation of the system. The mouthpiece portion 12 may include an annular resilient element that engages the surface of the cartridge and is compressed between the rigid mouthpiece housing element and the cartridge when the mouthpiece portion 12 is in the closed position. This ensures that a good electrical connection is maintained despite manufacturing tolerances. Of course, other mechanisms for maintaining a good electrical connection between the cartridge and the device may be employed.

[0129] Figure 2 is used in aerosol generating systems (e.g. Figure 1a and 1b Schematic diagram of an exemplary nebulizer and conductivity sensor 100 for an aerosol generating system (e.g., an ionizer). The nebulizer and conductivity sensor 200 are configured as a two-point conductivity sensor.

[0130] Figure 2 A plan view of a combined nebulizer and conductivity sensor 100 of a cartridge is shown received in an aerosol generating device and electrically connected to the device's control electronics 110. The cartridge comprises a liquid storage portion including a generally cylindrical body of capillary material 102 in which a liquid aerosol-forming substrate is retained. Figure 2The nebulizer and conductivity sensor 100 shown in FIG are arranged over and in contact with an end of a generally cylindrical body of capillary material 102. The capillary material 102 is configured such that a liquid aerosol-forming substrate held in the capillary material is drawn by capillary action to the end of the capillary body that is in contact with the nebulizer and conductivity sensor 100.

[0131] The nebulizer and conductivity sensor 100 includes two electrodes, a first electrode 104 and a second electrode 106. Each of the first electrode 104 and the second electrode 106 includes a resistive heating grid comprising a plurality of electrically conductive heater filaments. The first electrode 104 is spaced apart from the second electrode 106 such that a cavity 108 exists between the first electrode 104 and the second electrode 106. The cavity 108 between the first electrode 104 and the second electrode 106 is sufficiently wide to electrically insulate the first electrode 104 from the second electrode 106 on the capillary material 102 when no liquid aerosol-forming substrate is present in the capillary material 102.

[0132] The first electrode 104 and the second electrode 106 are configured such that the liquid aerosol-forming substrate at the end of the capillary body contacts the first electrode 104 and the second electrode 106 .

[0133] exist Figure 2 In the embodiment shown, the first electrode 104 and the second electrode 106 are electrically connected to an aerosol generating device (not shown) (e.g. Figure 1a and 1b The control electronics of the aerosol generating device are configured to control the supply of power to the first electrode 104 and the second electrode 106 from a power supply of the device.

[0134] In this embodiment, the control electronics of the aerosol-generating device comprise separate conductivity measurement circuitry 111 and aerosol generation circuitry 112. Each of the conductivity measurement circuitry 111 and aerosol generation circuitry 112 comprises electrical contacts in the form of resilient pin contacts for providing a reliable electrical connection between the control electronics of the aerosol-generating device and the first electrode 104 and the second electrode 106 when the cartridge is received in the device.

[0135] Each of the first electrode 104 and the second electrode 106 is electrically connected to the conductivity measurement circuit 111 through a single electrical contact. Thus, the conductivity measurement circuit includes two electrical contacts, one for each electrode 104,106.

[0136] The conductivity measurement circuit 111 is configured to supply an alternating voltage between two electrical contacts of the conductivity measurement circuit, which in turn establishes an alternating voltage between the first electrode 104 and the second electrode 106. The alternating voltage between the first electrode 104 and the second electrode 106 drives an alternating current across the cavity 108 between the first electrode 104 and the second electrode 106 through the liquid aerosol-forming substrate disposed in the cavity 108. The conductivity measurement circuit 111 is further configured to measure the current between the first electrode 104 and the second electrode 106 and, based on the measured current, determine the conductivity of the liquid aerosol-forming substrate disposed in the cavity 108. The conductivity of the liquid aerosol-forming substrate provides an indication of the nicotine concentration in the liquid aerosol-forming substrate.

[0137] Each of the first electrode 104 and the second electrode 106 is also electrically connected to an aerosol generating circuit 112 via two electrical contacts. Each of the first electrode 104 and the second electrode 106 is electrically connected to a first electrical contact at a first end of the electrode and to a second electrical contact at a second end of the electrode opposite the first end. The aerosol generating circuit 112 is configured to supply a voltage between the first electrical contact and the second electrical contact of each of the first electrode 104 and the second electrode 106. The voltage on the first electrode 104 between the first and second electrical contacts drives a current through the first electrode 104 between the first and second electrical contacts. The voltage on the second electrode 204 between the first and second electrical contacts drives a current through the second electrode 204, driving a current through the second electrode 106 between the first and second electrical contacts. The current passing through each electrode is suitable for heating the electrode. The aerosol generating circuit 112 is configured to supply direct current in pulses between the two electrical contacts of each electrode 104, 106. The aerosol generating circuit 112 is configured to vary the duty cycle of the pulses of direct current to vary the temperature of the electrodes 104 , 106 .

[0138] The conductivity measurement circuit 111 is configured to supply a first power to the first electrode 104 and the second electrode 106, and the aerosol generation circuit 112 is configured to supply a second power to the first electrode 104 and the second electrode 106. Preferably, the first power is insufficient to heat the heater filaments of the electrodes 104, 106 and insufficient to vaporize the liquid aerosol-forming substrate in contact with the heater filaments. The second power is sufficient to heat the heater filaments of the first electrode 104 and the second electrode 106 to vaporize the liquid aerosol-forming substrate in contact with the heater filaments. The aerosol generation circuit 112 is configured to vary the second power based on the conductivity of the liquid aerosol-forming substrate determined by the conductivity measurement circuit 111, the conductivity providing an indication of the nicotine concentration in the liquid aerosol-forming substrate.

[0139] In this embodiment, the conductivity measurement circuit 111 is configured to supply a first power to the first electrode 104 and the second electrode 106, and to measure the conductivity of the liquid aerosol-forming substrate disposed in the cavity 108 before the aerosol generation circuit 112 supplies a second power to the first electrode 104 and the second electrode 106 to heat the liquid aerosol-forming substrate. This enables the aerosol generation circuit 112 to adjust the second power in response to the nicotine concentration of the liquid aerosol-forming substrate determined before each aerosol generation cycle (e.g., each time a user puffs on the aerosol generating system to receive aerosol from the system).

[0140] Figure 3 is a schematic diagram of another exemplary nebulizer and conductivity sensor 200 for an aerosol generating system. The nebulizer and conductivity sensor 200 is configured as a two-point conductivity sensor.

[0141] In this embodiment, the tube (not shown) includes a liquid delivery element 202 in the form of a wick having at least one end that contacts the liquid aerosol-forming substrate in the liquid storage portion of the tube. The combined atomizer and conductivity sensor 200 of this embodiment includes two electrodes 204 and 206 in the form of coils arranged at a portion of the liquid delivery material 202 outside the liquid storage portion. The liquid delivery material 202 is arranged to draw the liquid aerosol-forming substrate from the liquid storage portion to the first coil electrode 204 and the second coil electrode 206 of the combined atomizer and conductivity sensor 200. Each coil electrode 204 and 206 includes a resistive heating wire concentrically wound in a spiral around a portion of the wick outside the liquid storage portion. The two coil electrodes 204 and 206 are substantially identical, wound together in the same direction around the wick and including the same number of turns. The second coil 206 is offset from the first coil 204 along the wick so that the cavity 208 is disposed between the corresponding turns of the first coil 204 and the second coil 206. The cavity between corresponding turns of the first coil 204 and the second coil 206 allows the liquid aerosol-forming substrate in the wick to be drawn into the cavity 208 and disposed between the coil electrodes 204 , 206 .

[0142] The first coil electrode 204 and the second coil electrode 206 are configured such that the liquid aerosol-forming substrate in the cavity 208 between the first coil electrode 204 and the second coil electrode 206 is in contact with the first coil electrode 204 and the second coil electrode 206 .

[0143] exist Figure 3 In the embodiment shown, the first coil electrode 204 and the second coil electrode 206 are electrically connected to an aerosol generating device (not shown) (e.g. Figure 1a and 1bThe control electronics of the aerosol generating device are configured to control the supply of power to the first electrode 204 and the second electrode 206 from a power supply of the device.

[0144] In this embodiment, the control electronics of the aerosol generating device comprise a shared conductivity measurement circuit 211 and an aerosol generating circuit 212. The conductivity measurement circuit 211 and the aerosol generating circuit 212 comprise shared electrical contacts.

[0145] Each of the first coil electrode 204 and the second coil electrode 206 is electrically connected to the aerosol generating circuit 212 by two electrical contacts, one at each end of the coil electrode. The aerosol generating circuit 212 is configured to supply a voltage between the contacts at opposite ends of each coil, so that a voltage is established across each of the first electrode 204 and the second electrode 206. The voltage on the first electrode 204 drives a current through the first electrode 204 to heat the electrode. The voltage on the second electrode 206 drives a current through the second electrode 206 to heat the electrode. The aerosol generating circuit 212 is configured to supply a direct current in pulses through each of the first electrode 204 and the second electrode 206. The aerosol generating circuit 212 is configured to vary the duty cycle of the pulses of the direct current to vary the temperature of the first electrode 204 and the second electrode 206.

[0146] In this embodiment, the conductivity measurement circuit 211 shares electrical contacts with the aerosol generation circuit 212. Each of the first coil electrode 204 and the second coil electrode 206 is electrically connected to the conductivity measurement circuit 211 by one electrical contact. The conductivity measurement circuit 211 is electrically connected to the first coil electrode 204 by an electrical contact at a first end of the first coil electrode 204, and is electrically connected to the second coil electrode 206 by an electrical contact at a second end of the second coil electrode 206 (being the end of the second coil electrode 206 farthest from the first end of the first coil electrode 204). Thus, the conductivity measurement circuit 211 includes two electrical contacts, one for each coil electrode 204, 206.

[0147] The conductivity measurement circuit 211 is configured to supply an AC voltage between two electrical contacts of the conductivity measurement circuit 211, which in turn establishes an AC voltage between the first coil electrode 204 and the second coil electrode 206. The AC voltage between the first coil electrode 204 and the second coil electrode 206 drives an AC current across the cavity 208 between the first electrode 204 and the second electrode 206 through the liquid aerosol-forming substrate disposed in the cavity 208. The conductivity measurement circuit 211 is further configured to measure the current between the first coil electrode 204 and the second coil electrode 206 and, based on the measured current, determine the conductivity of the liquid aerosol-forming substrate disposed in the cavity 208. The conductivity of the liquid aerosol-forming substrate provides an indication of the nicotine concentration in the liquid aerosol-forming substrate.

[0148] The conductivity measurement circuit 211 is configured to supply a first power to the first coil electrode 204 and the second coil electrode 206, and the aerosol generation circuit 212 is configured to supply a second power to the first electrode 204 and the second electrode 206. Preferably, the first power is insufficient to heat the coil electrodes 204, 206 and insufficient to vaporize the liquid aerosol-forming substrate in contact with the coil electrodes. The second power is sufficient to heat the first coil electrode 204 and the second coil electrode 206 and vaporize the liquid aerosol-forming substrate in contact with the coil electrodes. The aerosol generation circuit 212 is configured to vary the second power based on the conductivity of the liquid aerosol-forming substrate determined by the conductivity measurement circuit 211, the conductivity providing an indication of the nicotine concentration in the liquid aerosol-forming substrate.

[0149] It should be understood that in other embodiments, the first coil electrode 204 and the second coil electrode 206 can be arranged in the same manner as described above with respect to Figure 2 The described atomizer and the first electrode 104 and the second electrode 106 of the conductivity sensor are similarly and separately electrically connected to the conductivity measurement circuitry and the aerosol generation circuitry of the aerosol generating device.

[0150] Figure 4 and Figure 5 is used in aerosol generating systems (e.g. Figure 1a and 1b Schematic diagram of another exemplary nebulizer and conductivity sensor 300 of an aerosol generating system (e.g., an aerosol generating system). The nebulizer and conductivity sensor 300 is configured as a four-point conductivity sensor.

[0151] Figure 4 A plan view of a combined atomizer and conductivity sensor 300 of a cartridge is shown, Figure 5 A plan view of a cartridge is shown received in an aerosol generating device and electrically connected to the control electronics 310 of the device.

[0152] The cartridge comprises a liquid storage portion comprising a generally cylindrical body of capillary material 302 in which a liquid aerosol-forming substrate is retained. Figure 4 and Figure 5 The nebulizer and conductivity sensor 300 shown in FIG are arranged above and in contact with an end of a generally cylindrical body of capillary material 302. The capillary material 302 is configured such that a liquid aerosol-forming substrate held in the capillary material is drawn by capillary action to the end of the capillary body that is in contact with the nebulizer and conductivity sensor 300.

[0153] The atomizer and conductivity sensor 300 includes four electrodes, a pair of outer electrodes 304 and a pair of inner electrodes 306. Each of the electrodes 304, 306 includes a resistive heating grid comprising a plurality of electrically conductive heater filaments.

[0154] The pair of outer electrodes 304 are spaced apart such that an outer cavity 308 exists between the outer electrodes 304. The outer cavity 308 between the outer electrodes 304 is wide enough to electrically insulate the outer electrodes 304 on the capillary material 302 from each other when no liquid aerosol-forming substrate is present in the capillary material 302.

[0155] The pair of inner electrodes 306 are disposed between the pair of outer electrodes 304, within the outer cavity 308. The pair of inner electrodes 306 are sufficiently spaced apart from the pair of outer electrodes 304 to electrically insulate the inner electrodes 306 on the capillary material 302 from the outer electrodes 304 when no liquid aerosol-forming substrate is present in the capillary material 302. The pair of inner electrodes 306 are spaced apart such that an inner cavity 309 exists between the inner electrodes 306. The inner cavity 309 between the inner electrodes 306 is sufficiently wide to electrically insulate the inner electrodes 306 on the capillary material 302 from each other when no liquid aerosol-forming substrate is present in the capillary material 302.

[0156] The liquid aerosol-forming substrate at the end of the capillary body that contacts the nebulizer and conductivity sensor 300 contacts the inner electrode 204 and the outer electrode 206 .

[0157] Providing four electrodes in this arrangement enables the combined atomizer and conductivity sensor 300 of this embodiment to function as a four-point conductivity sensor, as described in more detail below.

[0158] exist Figure 5 , an aerosol generating device (not shown) (e.g., Figure 1a and 1b The inner electrode 304 and the outer electrode 306 are electrically connected to control electronics 310 of an aerosol generating device. The control electronics 310 of the aerosol generating device is configured to control power supply to the outer electrode 304 and the inner electrode 306 from a power supply of the device.

[0159] In this embodiment, the control electronics 310 of the aerosol generating device include shared conductivity measurement circuitry and aerosol generation circuitry, as described below with reference to Figure 6a -d is described in more detail. In this embodiment, the conductivity measurement circuit and the aerosol generation circuit include shared electrical contacts in the form of spring pin contacts, which are used to provide a reliable electrical connection between the control electronics 310 of the aerosol generating device and the inner electrode 304 and the outer electrode 306. It will be appreciated that in other embodiments, the aerosol generation circuit and the conductivity measurement circuit may include separate electrical contacts.

[0160] In this embodiment, each of the inner electrode 304 and the outer electrode 306 is electrically connected to the control circuit 310 by two electrical contacts. Each of the inner electrode 304 and the outer electrode 306 is electrically connected to a first electrical contact at a first end of the electrode and to a second electrical contact at a second end of the electrode opposite the first end.

[0161] Figure 6a -d schematically shows the combination Figure 4 and Figure 5 Some components of an exemplary embodiment of control electronics 310 for a combined nebulizer and conductivity sensor aerosol generating device.

[0162] The control electronics are configured to operate in two different modes, conductivity measurement mode and heating mode. In conductivity measurement mode, an AC voltage is supplied between the two outer electrodes 304 and the voltage across the two inner electrodes 306 is measured. In heating mode, a pulsed DC current is supplied to each of the inner and outer electrodes 304, 306, respectively, to heat the heater filaments of the electrodes and vaporize the liquid aerosol-forming substrate in contact with the heater filaments.

[0163] In this embodiment, the control electronics 310 generally comprises a DC power supply V DC , a microcontroller 320 and a plurality of transistor switches. The transistor switches are field effect transistors (FETs) controlled by control electronics to power the combined atomizer and conductivity sensor according to conductivity measurement mode and heating mode.

[0164] exist Figure 6a -d, the first outer electrode among the outer electrodes is shown as E1, the second outer electrode among the outer electrodes is shown as E4, the first inner electrode among the inner electrodes is shown as E2, and the second inner electrode among the inner electrodes is shown as E3. Figure 6a As shown in 1- E4 is connected to the control electronics by two electrical contacts spaced apart at opposite ends of the electrode. Each electrode E1-E4 is connected to the control electronics by a first transistor switch T 1a -T4a The first electrical contact is connected to a DC power source. Each electrode is also connected to a second transistor switch T by a second electrical contact. 1b -T 4b With the third transistor switch T 1c -T 4c The first transistor switch T 1a -T 4a This enables the control electronics to individually isolate each of the electrodes from the power supply when the transistor is off. The second transistor switch T is discussed in further detail below. 1b -T 4b and the third transistor switch T 1c -T 4c function.

[0165] In conductivity measurement mode, the control electronics supplies a high-frequency AC switching voltage to the first and second transistors T of the outer electrodes. 1a 、T 1b 、T 4a 、T 4b The base of each of them makes that during half a cycle, transistor T 1a and T 4b The transistor T is turned on and 1b and T 4a turns off, and during the other half cycle, transistor T 1b and T 4a The transistor T is turned on and 1a and T 4b Shut down.

[0166] Figure 6b shows that the transistor T 1a and T 4b The combined nebulizer and conductivity sensor is connected to the power supply during the first half of the conduction cycle in conductivity measurement mode. Figure 6b The arrangement shown in may be considered to include a first drive circuit operative to provide a first periodic voltage drop across the outer electrodes E1 , E4, the first periodic voltage drop having a selected frequency F and having an amplitude ranging from a first value to a second value lower than the first value.

[0167] Figure 6c shows that the transistor T 4a and T 1c The combined nebulizer and conductivity sensor is connected to the power supply during the second half of the conduction cycle in conductivity measurement mode. Figure 6c The arrangement shown in can be viewed as providing a second periodic voltage drop across the outer electrodes E1 , E4 having the same frequency and amplitude as the first periodic voltage drop but opposite polarity and completely out of phase with the first periodic voltage drop.

[0168] The first periodic voltage drop and the second periodic voltage drop have opposite polarities to each other, where opposite polarity in this article refers to the relative position of the high voltage side and the low voltage side, rather than requiring positive and negative voltages. Since the first periodic voltage drop and the second periodic voltage drop are applied from opposite electrodes in the outer electrode. Since the first periodic voltage drop and the second periodic voltage drop have opposite polarities and are completely out of phase, an AC voltage is effectively supplied to the outer electrode. The first periodic voltage drop and the second periodic voltage drop can have any suitable waveform. For example, the two waveforms can be square waves that are completely out of phase with each other. Advantageously, the control electronics can be configured to provide a dead time period of at least a few nanoseconds between the end of one voltage drop and the beginning of the next voltage drop in the opposite direction to avoid burning out the switch.

[0169] In the first half period, the second transistor T of the second external electrode E4 4b The microprocessor 220 is configured to measure a voltage V3 across the resistor R2 and determine a current flowing between the first and second external electrodes E1 and E4 based on the measured voltage V3 and the known resistance R2.

[0170] In the second half period, the second transistor T of the first external electrode E1 1b The control electronics are configured to measure a voltage V1 across the resistor R1 and to determine a current flowing between the second external electrode E4 and the first external electrode E1 based on the measured voltage V1 and the known resistance R1.

[0171] During the conductivity measurement mode, the control electronics is further configured to provide a second crystal T of the two inner electrodes E2, E3 1b 、T 2b The base of each of the two inner electrodes E2, E3 is supplied with a voltage so that the second transistor T 1b 、T 2b In conductivity measurement mode, the control electronics does not supply voltage to the third transistors of any inner or outer electrode, so that all third transistors remain off.

[0172] The second transistor T of the inner electrodes E2 and E3 2b 、T 3b Each of provides a path to the input of a differential amplifier 322, the output of which is supplied to the microprocessor 320 to provide the microprocessor 320 with a measurement of the voltage V2 across the inner electrodes E2, El.

[0173] The microprocessor 320 can be configured in a number of different ways to use the measured voltages V1, V2, and V3 to determine an indication of the nicotine concentration in the liquid aerosol-forming substrate between the electrodes of the combined atomizer and conductivity sensor. In this embodiment, the microprocessor 320 is configured to use the measured voltages V1, V3 to determine the current between the outer electrodes E1, E4, and to use the determined current and the measured voltage V2 across the inner electrodes E2, E3 to determine the conductivity of the liquid aerosol-forming substrate and to determine an indication of the nicotine concentration in the liquid aerosol-forming substrate.

[0174] In heating mode, the control electronics supplies a high frequency AC switching voltage to the first transistors T of all electrodes E1, E2, E3, E4. 1a 、T 2a 、T 3a 、T 4a The control electronics also supplies voltage to the base of each of the electrodes E1, E2, E3, E4, so that all first transistors alternate periodically between being on and off. 2c 、T 3c 、T 4c The base of each of the third transistors is turned on. 1c 、T 2c 、T 3c 、T 4c Provides a path to electrical ground.

[0175] Figure 6d shows that the transistor T 1a 、T 2a 、T 3a 、T 4a 、T 1c 、T 2c 、T 3c and T 4c In the on state, the combination atomizer and conductivity sensor 300 is connected to the power source in the heating mode. Figure 6d The arrangement shown in may be considered to include a third drive circuit operative to supply current across each of the electrodes.

[0176] The control electronics supplies pulsed direct current to each of the electrodes by periodically switching the first transistor between on and off and by maintaining the third transistor on. The control electronics is configured to control the duty cycle of the pulses to control the temperature to which the electrodes are heated. Preferably, the control electronics is configured to control the duty cycle in the heating mode based on an indication of nicotine concentration determined in the conductivity measurement mode.

[0177] It will be appreciated that in other embodiments, the control electronics of the aerosol generating device may not be arranged to directly supply power to the inner electrode to heat the inner electrode, but rather the control electronics may be arranged to heat the inner electrode by induction. In these embodiments, an oscillating voltage is applied to the outer electrode, which induces a current in the inner electrode. In order to heat the inner electrode to a sufficient temperature, it is preferred that the inner electrode be a susceptor element formed of a magnetic material, such as AISI 4xx stainless steel. While the outer electrode may be formed of a magnetic material, this is not a necessary requirement in these embodiments.

[0178] Figure 7 and Figure 8 A schematic diagram of another exemplary conductivity sensor 400 is shown. In this embodiment, the conductivity sensor 400 is not combined with a nebulizer. In this embodiment, the conductivity sensor is configured as a four-point conductivity sensor that is arranged in the liquid storage portion of the cartridge of the aerosol generating device.

[0179] The cartridge includes a housing 401 defining a substantially cubic liquid storage portion. The housing is formed of a rigid electrically insulating material (e.g., PEEK). The conductivity sensor 400 includes four electrodes, namely, two outer electrodes 404 and two inner electrodes 406. A first outer electrode of the outer electrodes 404 and a first inner electrode of the inner electrodes 406 are arranged on a first inner surface of the cartridge housing 401, and a second outer electrode of the outer electrodes 404 and a second inner electrode of the inner electrodes 406 are arranged on a second inner surface of the cartridge housing 401 opposite to the first surface, such that the first outer electrode and the first inner electrode face the second outer electrode and the second inner electrode opposite the liquid storage portion.

[0180] The outer electrode 404 comprises an identical ring-shaped electrode defining an outer electrode cavity 407. The inner electrode 406 comprises an identical circular electrode. Figure 8 As shown in FIG, at a first inner surface of the cartridge housing 401, a first outer electrode 404 and a first inner electrode 406 are concentrically arranged, wherein the first inner electrode 406 is arranged in an outer electrode cavity 405 of the first outer electrode 404. Similarly, at a second inner surface of the cartridge housing 401, the first outer electrode 404 and the first inner electrode 406 are concentrically arranged, wherein the second inner electrode 406 is arranged in the outer electrode cavity 405 of the second outer electrode 404. The outer diameter of the inner electrode 406 is smaller than the inner diameter of the outer electrode 404, such that a cavity is provided between the inner electrode 404 and the outer electrode 406. When no liquid aerosol-forming substrate is provided in the cavity, the cavity between the inner electrode 404 and the outer electrode 406 electrically insulates the inner electrode 406 from the outer electrode 404.

[0181] like Figure 7, the first inner electrode and the first outer electrode at the first inner side of the cartridge housing 401 are aligned with the second inner electrode and the second outer electrode at the second inner side of the cartridge housing 401. Thus, the first and second outer electrodes 404 are substantially separated by the width of the liquid storage portion, thereby forming a cavity 408, and the first and second inner electrodes 406 are also substantially separated by the cavity 408, which is formed by the width of the liquid storage portion.

[0182] When the liquid aerosol-forming substrate is disposed in the liquid storage portion, the liquid aerosol-forming substrate may be disposed in the cavity 408 and in contact with the first electrode 404 and the second electrode 406. In this embodiment, the liquid aerosol-forming substrate is free to move within the liquid storage portion. However, in other embodiments, a carrier material may be disposed in the liquid storage portion to retain the liquid aerosol-forming substrate. Such a carrier material is typically a porous, electrically insulating material disposed in the cavity 408 in contact with the inner electrode 404 and the outer electrode 406.

[0183] like Figure 7 As shown in FIG, each of the outer electrodes 404 is electrically connected to the control electronics 410 of the aerosol generating device. Similarly, each of the inner electrodes 406 is electrically connected to the control electronics 410 of the aerosol generating device. Each electrode 404, 406 is electrically connected to the control electronics 410 by one electrical contact.

[0184] The control electronics 410 is configured to supply an AC voltage to the outer electrodes 404, which can drive an AC current through the liquid aerosol-forming substrate in the cavity 408 disposed between the first and second outer electrodes 404. The control electronics is configured to measure the current between the first and second outer electrodes 404.

[0185] An alternating current driven by the control electronics 410 between the first and second outer electrodes 404 establishes an alternating voltage between the first and second inner electrodes 406. The control electronics 410 is configured to measure the voltage across the first and second inner electrodes. The control electronics are further configured to use the current and voltage measurements to determine the conductivity of the liquid aerosol-forming substrate disposed in the cavity 408. The control electronics 410 may also determine the nicotine concentration in the liquid aerosol-forming substrate based on the determined conductivity.

[0186] It should be understood that in other embodiments, the four-point conductivity sensor 400 may be replaced by a two-point conductivity sensor having a first electrode at a first side of the liquid storage portion and a second electrode at a second side of the liquid storage portion.

[0187] In this embodiment, the conductivity sensor 400 is disposed in the liquid storage portion of the cartridge; however, it will be appreciated that in other embodiments the conductivity sensor 400 may be disposed in the liquid storage portion of the aerosol generating device or in a conduit between the liquid storage portion and the nebulizer.

[0188] Figure 9 and Figure 10 A schematic diagram of another exemplary conductivity sensor 500 is shown. In this embodiment, the conductivity sensor 500 is not combined with a nebulizer. In this embodiment, the conductivity sensor 500 is an inductive conductivity sensor arranged in the liquid storage portion of the cartridge of the aerosol generating device.

[0189] Conductivity sensor 500 includes two electrodes 504, 506 in the form of annular coils. A first of the coil electrodes is a drive coil 504 wound around a first loop 505 of ferromagnetic material. A second of the coil electrodes is a receive coil 506 wound around a second loop 507 of ferromagnetic material. The receive coil 506 and loop 507 are substantially identical to the drive coil 504 and loop 505, specifically, have the same number of turns and are wound in the same direction.

[0190] Each of the drive coil 504 and the receiving coil 506 has an internal cavity through which the aerosol-forming substrate can flow. The receiving coil 506 is aligned with the drive coil 504 on the axis and is spaced apart from the drive coil 504 along the axis so that the receiving coil cavity and the drive coil cavity are aligned to form a substantially continuous cylindrical cavity through which the liquid aerosol-forming substrate can flow. The drive coil 504 is arranged and configured to induce a current in the receiving coil 506 when an alternating current voltage is supplied to the drive coil 504.

[0191] Each end of the drive coil 504 and the receiver coil 506 is electrically connected to the control electronics 510 of the aerosol generating device.

[0192] The driving coil 504 and the ferromagnetic ring 505 as well as the receiving coil 506 and the ferromagnetic ring 507 are embedded in an annular cylindrical body 512 of an electrically insulating material (e.g., a plastic material) that is substantially impermeable to the liquid aerosol-forming matrix. Therefore, the body 512 has the form of a cylindrical tube having an inner cavity 514 extending through the body 512 and open at both ends. The body 512 is provided to protect the coil electrodes from the influence of the liquid aerosol-forming matrix. The body 512 is configured to be arranged in the liquid storage portion of the barrel so that the liquid aerosol-forming matrix in the liquid storage portion can flow through the inner channel 514 and flow around the outer surface of the body 501.

[0193] In use, the control electronics 510 are configured to supply power in the form of an AC voltage to the drive coil 504. The AC voltage in the drive coil 504 generates a magnetic field which induces a current in the liquid aerosol-forming substrate disposed in the inner cavity 514. The current in the inner cavity 514 is generated by Figure 7 506 . The current 516 induced in the liquid aerosol-forming substrate also generates a magnetic field, which induces a current in the receiving coil 506 . The conductivity of the liquid aerosol-forming substrate affects the magnitude of the current 516 induced in the liquid aerosol-forming substrate, which in turn affects the magnitude of the current induced in the receiving coil 506 . The control electronics 510 is configured to measure one or both of the voltage and current induced in the receiving coil, and is further configured to determine the conductivity of the liquid aerosol-forming substrate based on one or more of the measured current and voltage induced in the receiving coil. The control electronics may also determine the concentration of nicotine in the liquid aerosol-forming substrate based on the determined conductivity.

Claims

1. An aerosol generating system comprising: a liquid storage portion for holding a liquid aerosol-forming substrate; an atomizer, the atomizer being fluidly connected to the liquid storage portion; a conductivity sensor arranged to sense the conductivity of the liquid aerosol-forming substrate from the liquid storage portion, the conductivity sensor comprising at least two electrodes; power supply; and Control electronics configured to: controlling power from the power source to the nebulizer to nebulize the liquid aerosol-forming substrate from the liquid storage portion; controlling the supply of power from the power supply to the electrodes of the conductivity sensor, the power being provided to the conductivity sensor as an AC voltage; receiving one or more measurements indicative of the conductivity of the liquid aerosol-forming substrate from the conductivity sensor; as well as The nicotine concentration of the liquid aerosol-forming substrate is determined based on one or more of the measurements from the conductivity sensor.

2. An aerosol-generating system according to claim 1 , wherein the control electronics is further configured to control the supply of power from the power supply to the atomizer to aerosolize the liquid aerosol-forming substrate based on the determined nicotine concentration of the liquid aerosol-forming substrate.

3. An aerosol generating system according to claim 2, wherein the control electronics is configured to control the power supplied from the power source to the atomizer to aerosolize the liquid aerosol-forming substrate based on the determined nicotine concentration of the liquid aerosol-forming substrate by comparing the determined nicotine concentration with a predetermined threshold value, supplying a first power to the atomizer when the determined nicotine concentration is equal to or lower than the predetermined threshold value, and supplying a second power, which is lower than the first power, to the atomizer when the determined nicotine concentration exceeds the predetermined threshold value.

4. An aerosol generating system according to any one of claims 1 to 3, wherein the aerosol generating system further comprises a heater arranged to heat the aerosol-forming substrate from the liquid storage portion, and wherein the control electronic device is configured to supply power from the power supply to the heater to heat the liquid aerosol-forming substrate from the liquid storage portion to a predetermined temperature.

5. An aerosol generating system according to any one of claims 1 to 3, wherein: The system further comprises a temperature sensor arranged to sense the temperature of the liquid aerosol-forming substrate from the liquid storage portion; and The control electronics are further configured to: receiving one or more measurements of the temperature of the liquid aerosol-forming substrate at the conductivity sensor from the temperature sensor; and The determination of the nicotine concentration is adjusted based on one or more of the temperature measurements.

6. An aerosol-generating system according to any one of claims 1 to 3, wherein each electrode of the conductivity sensor is arranged to contact liquid aerosol-forming substrate from the liquid storage portion.

7. An aerosol-generating system according to claim 6, wherein the conductivity sensor comprises two electrodes, and wherein the two electrodes are spaced apart to form a cavity, the liquid aerosol-forming substrate from the liquid storage portion being disposed in the cavity.

8. An aerosol generating system according to claim 7, wherein the nebulizer is a thermal nebulizer comprising a plurality of heating elements, and wherein each electrode of the conductivity sensor is formed by a heating element of the nebulizer.

9. An aerosol generating system according to claim 8, wherein the control electronics is further configured to: supplying a first power to electrodes of the conductivity sensor to measure the conductivity of the liquid aerosol-forming substrate; and A second power is supplied to a plurality of heating elements of the atomizer to atomize the liquid aerosol-forming substrate, the second power being greater than the first power.

10. An aerosol generating system according to claim 6, wherein: The conductivity sensor includes two inner electrodes and two outer electrodes; the two outer electrodes being spaced apart to form an outer cavity, the liquid aerosol-forming substrate from the liquid storage portion being disposed in the outer cavity; the two inner electrodes are arranged in the outer cavity, between the two outer electrodes, and spaced apart to form an inner cavity, in which the liquid aerosol-forming substrate from the liquid storage portion is disposed; and The control electronics are further configured to: supplying power from the power source to the outer electrode, the power being supplied to the outer electrode as an AC voltage; and One or more measurements indicative of the electrical conductivity of the liquid aerosol-forming substrate are received from the inner electrode.

11. An aerosol generating system according to claim 10, wherein the nebulizer is a thermal nebulizer comprising a plurality of heating elements, and wherein each electrode of the conductivity sensor is formed by a heating element of the nebulizer.

12. An aerosol generating system according to claim 11, wherein the control electronics is further configured to: supplying a first power to an outer electrode of the conductivity sensor to measure the conductivity of the liquid aerosol-forming substrate; and A second power is supplied to a plurality of heating elements of the atomizer to atomize the liquid aerosol-forming substrate, the second power being greater than the first power.

13. An aerosol generating system according to any one of claims 1 to 3, wherein the conductivity sensor comprises two electrodes, namely a first electrode and a second electrode, each electrode forming a coil, wherein the control electronic device is configured to supply an alternating voltage to the first electrode, and the control electronic device is configured to receive one or more measurement values ​​indicative of the conductivity of the liquid aerosol-forming substrate from the second electrode, and wherein the first electrode is arranged to induce a current in the second electrode when the alternating voltage is supplied to the first electrode.

14. An aerosol generating system according to claim 13, wherein the first electrode and the second electrode are arranged in the liquid storage portion.

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