RU2819620C2 - Device and system for generating aerosol with conductivity sensor - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: group of inventions relates to an aerosol generation system and a cartridge for an aerosol generation system. Aerosol-generating system comprises: a liquid storage portion for retaining a liquid aerosol-forming substrate; sprayer in fluid communication with the liquid storage portion; conductivity sensor; power supply unit; and control electronics. Conductivity sensor comprises at least two electrodes and is arranged to measure the conductivity of the aerosol-forming liquid substrate from the liquid storage part. Control electronics is configured to: control the supply of power from the power supply to the sprayer for spraying the aerosol-forming liquid substrate from the liquid storage portion; and controlling the power supply from the power supply to the conductivity sensor electrodes, wherein the power supply to the conductivity sensor is made in the form of alternating voltage. Control electronics is further configured to: receive one or more measurements indicative of the conductivity of the aerosol-forming liquid substrate from the conductivity sensor; and determining the nicotine concentration in the aerosol-forming liquid substrate based on one or more measurements from the conductivity sensor.

EFFECT: enabling assessment of the nicotine concentration in the liquid formulation and controlling the nicotine concentration in aerosols generated from different liquid formulations.

15 cl, 14 dwg

Description

The present invention relates to an aerosol generating system (aerosol generating system) that sprays an aerosol-forming substrate containing nicotine to generate an aerosol. In particular, the present invention relates to an aerosol generating system (aerosol generating system) comprising a conductivity sensor. The present invention also relates to an aerosol generating device (aerosol generating device) comprising a conductivity sensor and a cartridge containing a conductivity sensor.

Widely used are aerosol generating systems (aerosol generating systems), such as electronic cigarettes, which operate by heating a liquid formulation to generate an aerosol for inhalation by users. Typically, these systems include a liquid storage portion that holds the liquid formulation, a heater for vaporizing the liquid formulation, a wick that moves liquid from the liquid storage portion to the heater, a power supply, and control electronics. Some of these systems include a fluid storage portion that is refillable. Some of these systems contain a device part and a replaceable cartridge. In some systems, the device portion contains the power supply and control electronics, and the cartridge contains a liquid storage portion that holds the liquid formulation, a heater for vaporizing the liquid formulation, and a wick that moves liquid from the liquid storage portion to the heater.

In systems comprising a refillable liquid storage portion, liquid formulations having different compositions may be introduced into the liquid storage portion when refilling the liquid storage portion. Likewise, in systems comprising a device part and a replaceable cartridge, different cartridges may contain liquid formulations having different compositions. In particular, different liquid formulations may contain different amounts or concentrations of nicotine. Accordingly, an aerosol generated from one particular liquid composition may contain a different amount or concentration of nicotine than an aerosol generated from another liquid composition.

WO 2015/015431 A1 describes a flavored vapor generator used for an electronic smoking apparatus, comprising a housing; a liquid-retaining material that is filled, impregnated, or immersed in a flavored liquid and placed within the housing; an electric heater for heating the liquid holding material to produce flavored vapor; and a sensor for monitoring the impregnation or moisture conditions of the liquid holding material and for providing signals to determine whether the flavor liquid in the liquid holding material is exhausted or nearly exhausted.

US 2018/177229 A9 describes a cartridge for an aerosol generation system that includes a liquid storage portion configured to store a liquid aerosol generating substrate. The liquid storage portion includes one or more flexible walls and is configured to change at least one of the shape and size of the liquid storage portion when the volume of the liquid aerosol-forming substrate held in the liquid storage portion changes. The cartridge includes a sensor configured to detect physical property data. The data relates to at least one of an appropriately shaped and appropriately sized liquid storage portion such that the volume of the liquid aerosol-forming substrate held in the liquid storage portion can be determined based on the measured data.

It would be desirable for the aerosol generating system to be able to estimate the concentration of nicotine in a liquid formulation. It would also be desirable if the aerosol generating system could control the concentration of nicotine in aerosols generated from different liquid formulations. It would also be desirable to be able to standardize the manufacture of the aerosol generating system regardless of the aerosol generating substrate that will be used with the aerosol generating system.

According to the present invention, there is provided an aerosol generating system, comprising: a liquid storage portion for holding a liquid aerosol-generating substrate; a sprayer in fluid communication with the liquid storage portion; conductivity sensor; power unit; and control electronics. The conductivity sensor contains at least two electrodes and is arranged to measure the electrical conductivity of the aerosol-forming liquid substrate from the liquid storage portion. The control electronics are configured to: control the supply of power from the power supply to the atomizer for spraying a liquid substrate forming an aerosol from the liquid storage portion; and controlling the supply of power from the power supply to the electrodes of the conductivity sensor, wherein power is supplied to the conductivity sensor in the form of alternating voltage. The control electronics are further configured to: receive one or more measurements indicative of the conductivity of the aerosol-forming liquid substrate from the conductivity sensor; and determining the concentration of nicotine in the aerosol-forming liquid substrate based on one or more measurements from the conductivity sensor.

The liquid aerosol-forming substrate may contain three main components, typically nicotine, an aerosol-forming agent and water. Advantageously, the present inventors have realized that the electrical conductivity of the liquid aerosol-forming substrate can provide an indication of the concentration of nicotine in the liquid aerosol-forming substrate. In particular, the present inventors realized that a manufacturer of an aerosol generating device may also make or sell branded liquid aerosol substrates having different nicotine concentrations, and that providing the aerosol generating device with a conductivity sensor may allow the device to determine which branded liquid the aerosol-forming substrate is placed in the device based on the electrical conductivity of the aerosol-forming substrate.

As used herein, the term "aerosol-forming substrate" refers to a substrate that can release volatile compounds that can form an aerosol. Volatile compounds can be released by heating the substrate to form an aerosol. Volatile compounds can be released by moving the aerosol-forming substrate through the passages of the vibrating element.

The aerosol-forming substrate is a liquid aerosol-forming substrate. The aerosol-forming substrate may contain a mixture of liquid and solid components. The aerosol-forming substrate contains nicotine. Preferably, the aerosol-forming substrate contains a nicotine salt. The aerosol-forming substrate may contain material of plant origin. The aerosol-forming substrate may contain tobacco. The aerosol-forming substrate may comprise tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate when heated. The aerosol-forming substrate may comprise non-tobacco material. The aerosol-forming substrate may contain homogenized material of plant origin. The aerosol-forming substrate may comprise homogenized tobacco material. The aerosol-forming substrate may contain at least one aerosol-forming substance. An aerosol generating agent is any suitable known compound or mixture of compounds which, when used, promotes the formation of a dense and stable aerosol and which is substantially resistant to thermal degradation at the operating temperature of the system. Suitable aerosol-forming agents are well known in the art and include, but are not limited to: polyhydric alcohols such as triethylene glycol, 1,3-butanediol and glycerol; polyhydric alcohol esters such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol-forming agents are polyhydric alcohols or mixtures thereof, such as triethylene glycol, 1,3-butanediol, and most preferably glycerol. The aerosol-forming substrate may contain other additives and ingredients such as flavoring agents.

In some preferred embodiments, the nicotine is present 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 concentration of the nicotine electrolyte may be substantially higher than the concentration of other electrolytes in the aerosol-forming liquid substrate. Accordingly, it may be possible to neglect the effect of changes in the concentration of other components of the aerosol-forming liquid substrate on the electrical conductivity of the substrate.

A manufacturer of liquid aerosol-forming substrates may produce different branded aerosol-forming substrates having different nicotine concentrations. To vary the concentration of nicotine in the aerosol-forming substrate, the manufacturer may increase or decrease the amount of nicotine in a given amount of substrate by, conversely, decreasing or increasing the amount of solvent, such as water, in a given amount of substrate. For example, a manufacturer may produce a low nicotine aerosol substrate containing a first amount of nicotine and a first amount of water for a given amount of substrate, and a high nicotine aerosol substrate containing 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. An aerosol-forming substrate with a low nicotine content may have a lower nicotine concentration than an aerosol-forming substrate with a high nicotine content. The low nicotine aerosol-forming substrate may have a first electrical conductivity, and the high nicotine aerosol-forming substrate may have a second electrical conductivity greater than the first electrical conductivity. The difference between the first electrical conductivity and the second electrical conductivity may increase with temperature.

The aerosol-forming liquid substrate may typically have a conductivity at 20 degrees Celsius from about 1 microsiemens per centimeter to about 500 microsiemens per centimeter, and preferably a conductivity at 20 degrees Celsius from about 1 microsiemens per centimeter to about 400 microsiemens per centimeter. Preferably, the conductivity sensor is suitable for measuring electrical conductivity values of aerosol-forming substrates in these ranges.

The conductivity sensor may be any suitable type of sensor for measuring the electrical conductivity of the aerosol-forming liquid substrate in the system.

The conductivity sensor may be located at any suitable location in the aerosol generating system. The conductivity sensor may be located in the liquid storage portion. The conductivity sensor may be located on or around the liquid storage portion. The conductivity sensor may be located on or around the atomizer. A conductivity sensor may be located between the liquid storage portion and the atomizer. In some embodiments, the conductivity sensor is a separate component from the atomizer. In some preferred embodiments, the nebulizer includes a conductivity sensor. In these preferred embodiments, the atomizer may comprise one or more elements and at least one of the conductivity sensor electrodes comprises a nebulizer element.

The conductivity sensor electrodes can be of any suitable shape. For example, the electrodes may be coil electrodes, ring electrodes, or mesh electrodes containing multiple filaments. In some embodiments, the electrodes may be positioned to come into contact with a liquid substrate forming an aerosol. In some embodiments, the electrodes may be positioned such that the electrodes do not come into contact with the aerosol-forming liquid substrate. In other words, the electrodes can be isolated from the liquid substrate that forms the aerosol.

In some first preferred embodiments, the conductivity sensor comprises two electrodes. The conductivity sensor according to these first preferred embodiments may be called a two-point conductivity sensor.

The two electrodes can be spaced apart so that a cavity is formed between the electrodes. For example, the two electrodes may be separated by a distance of from about 1 millimeter to about 20 millimeters. As used herein, the term “cavity” refers to any suitable gap or space between two electrodes, including both the two-dimensional space between two completely planar electrodes located in the same plane and the three-dimensional space between two electrodes. The two electrodes may be positioned such that the aerosol-forming liquid substrate may be present in the cavity between the electrodes. Preferably, two electrodes are arranged in contact with an aerosol-forming liquid substrate from the liquid storage portion. The two electrodes may be arranged such that the two electrodes are electrically isolated from each other when the aerosol-forming liquid substrate is not present in the cavity between the electrodes.

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

In these first preferred embodiments, when the liquid aerosol-forming substrate is located in the cavity between the electrodes, applying an alternating voltage to the two electrodes can cause an alternating 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 sense a current between two electrodes. The control electronics may be configured to sense a voltage between two electrodes. One or more of the measured current and voltage may be used to determine the electrical conductivity of the aerosol-forming liquid substrate located in the cavity between the two electrodes.

In these first preferred embodiments, the control electronics may be configured to apply an alternating voltage to the conductivity sensor with a frequency of from about 1 kHz to about 500 kHz.

In some second preferred embodiments, the conductivity sensor includes four electrodes. The conductivity sensor according to these second preferred embodiments may be referred to as a four-point conductivity sensor.

The conductivity sensor may include two internal electrodes and two external electrodes. The two outer electrodes may be spaced apart such that an outer cavity is formed between the two outer electrodes. For example, the two outer electrodes may be spaced apart from about 5 millimeters to about 20 millimeters. The two inner electrodes may be spaced apart to form an internal cavity between the two inner electrodes. For example, the two inner electrodes may be spaced apart from about 5 millimeters to about 20 millimeters. In some embodiments, two inner electrodes are located in an outer cavity between two outer electrodes. In these embodiments, the two inner electrodes may be spaced apart from about 1 millimeter to about 18 millimeters.

The two outer electrodes may be positioned such that the aerosol-forming liquid substrate may be contained in an outer cavity between the two outer electrodes. The two outer electrodes may be arranged such that the two outer electrodes are electrically isolated from each other when the aerosol-forming liquid substrate is not located in the outer cavity between the outer electrodes.

The two inner electrodes may be positioned such that the aerosol-forming liquid substrate may be contained in an internal cavity between the two inner electrodes. The two inner electrodes may be positioned such that the two inner electrodes are electrically isolated from each other when the aerosol-forming liquid substrate is not located in the inner cavity between the inner electrodes. The two inner electrodes may also be arranged such that the two inner electrodes are electrically isolated from the two outer electrodes when the aerosol-forming liquid substrate is not located in the inner cavity between the inner electrodes.

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

In these second preferred embodiments, the control electronics may be configured to supply power from the power supply to the external electrodes in the form of an alternating voltage. The control electronics may be configured to receive from the external electrodes one or more measurements indicative of the conductivity of the aerosol-forming liquid substrate. The control electronics may be configured to receive from the internal electrodes one or more measurements indicative of the conductivity of the aerosol-forming liquid substrate.

In these second preferred embodiments, when the liquid aerosol-forming substrate is located in the outer cavity between the two outer electrodes, applying an alternating voltage to the two outer electrodes can cause an alternating current to flow between the two outer electrodes through the liquid aerosol-forming substrate located in the outer cavity . When the aerosol-forming liquid substrate is in the outer cavity, the aerosol-forming liquid substrate is also in the inner cavity between the two inner electrodes. When alternating current flows between the two outer electrodes, alternating current also flows between the two inner electrodes, creating an alternating voltage across the two inner electrodes.

The control electronics may be configured to measure the voltage drop between the two internal electrodes. The measured voltage drop between the two inner electrodes can be used to determine the electrical conductivity of the aerosol-forming liquid substrate located in the internal cavity between the two inner electrodes. The control electronics may be configured to sense a current between two external electrodes. The measured current between the two outer electrodes can be used to determine the electrical conductivity of the aerosol-forming liquid substrate located in the outer cavity. In some particularly preferred embodiments, the control electronics are configured to use the measured voltage drop between the two inner electrodes and the measured current between the two outer electrodes to determine the electrical conductivity of the aerosol-forming liquid substrate. The electrical conductivity of the liquid substrate forming the aerosol may be proportional to the applied current.

Advantageously, a four-point conductivity sensor can minimize the effect of parasitic resistances on the conductivity sensor's voltage measurements. Parasitic resistances in a conductivity sensor, such as contact resistances between leads in contact with the electrodes, can cause errors in voltage measurements. The advantageous four-electrode arrangement of the second preferred embodiments allows voltage measurements to be separated from current measurements. Separating voltage measurements from current measurements can minimize the influence of parasitic resistances on voltage measurements.

In the four-point conductivity sensors of second preferred embodiments, the inner electrodes are arranged such that the current between the inner electrodes is substantially the same as the current passed between the outer electrodes. If the voltage across the internal electrodes is measured at high impedance, then little current may flow through the terminals connected to the internal electrodes compared to the current between the internal electrodes. Since the current through the terminals connected to the internal electrodes is negligible compared to the current between the internal electrodes, the voltage drop across the terminals connected to the internal electrodes caused by parasitic resistances may be negligible compared to the voltage drop across the internal electrodes. As a result, voltage measurements at the internal electrodes may include minimal or negligible contributions from parasitic resistances.

In addition, since voltage measurements at the two inner electrodes cause negligible current to flow, the polarization of the aerosol-forming liquid substrate at the two inner electrodes may also be negligible, thereby minimizing the influence of polarization on voltage measurements in a four-electrode arrangement according to second preferred embodiments. .

In these second preferred embodiments, the control electronics may be configured to apply an alternating voltage to the conductivity sensor with a frequency of from about 1 kHz to about 500 kHz.

In some of these second preferred embodiments, the two inner electrodes may be current collector-type elements. As used herein, the term "susceptor element" refers to an element containing a material that can convert electromagnetic energy into heat. When an element in the form of a pantograph is in an alternating electromagnetic field, the pantograph heats up. Heating of the pantograph element may result from at least one of hysteresis losses and eddy currents induced in the pantograph, depending on the electrical and magnetic properties of the pantograph material. Accordingly, applying an alternating voltage to the two outer electrodes to heat the outer electrodes can induce a current in the two inner electrodes. The current induced in the two inner electrodes may be sufficient to heat the two inner electrodes.

The current collector element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for the elongated current collector element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel compounds, titanium and composite metal materials. Preferred current collector elements comprise metal or carbon. Advantageously, the current collector element may comprise or consist of a ferromagnetic material, for example ferritic iron, a ferromagnetic alloy such as ferromagnetic steel or stainless steel, ferromagnetic particles and ferrite.

In some third preferred embodiments, the conductivity sensor includes two electrodes: a first electrode and a second electrode. Preferably, each electrode forms a winding. The first electrode is positioned to induce current in the second electrode when an alternating voltage is applied to the first electrode. The two electrodes can be spaced apart so that a cavity is formed between the electrodes. The two electrodes may be arranged such that the two electrodes are electrically isolated from each other.

When the first and second electrodes form windings, the winding of the first electrode may be wound around the first inner cavity. A winding of the second electrode may be wound around the second internal cavity. The first electrode and the second electrode may be positioned such that the first internal cavity is aligned with the second internal cavity. The first internal cavity and the second internal cavity may define an internal cavity. The internal cavity may define a passage through which a liquid substrate may flow to form an aerosol.

The conductivity sensor according to these third preferred embodiments may be called an inductive conductivity sensor.

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

In these third preferred embodiments, when the liquid aerosol-forming substrate is located in the internal cavity between the first electrode and the second electrode, application of an alternating voltage to the first electrode may cause an alternating current to be generated in the second electrode by induction. An alternating voltage applied to the first electrode generates a varying magnetic field that causes current to flow through the liquid substrate forming an aerosol located in the internal cavity. The magnitude and direction of the electrical current flowing through the aerosol-forming liquid substrate located in the internal cavity affects the alternating current generated in the second electrode. The control electronics may be configured to measure a current or voltage induced in the second electrode. The measured current or voltage can be used to determine the electrical conductivity of the aerosol-forming liquid substrate located in the internal cavity between the first and second electrodes. The current induced in the second electrode may be proportional to the electrical conductivity of the liquid substrate forming the aerosol.

In these third preferred embodiments, the first and second electrodes may be shielded or isolated from the aerosol-forming substrate. In other words, the first and second electrodes may be positioned such that the first and second electrodes do not come into contact with the aerosol-forming liquid substrate. The first and second electrodes may be located in a conductivity sensor housing. The conductivity sensor body may define an internal cavity, including a first internal cavity and a second internal cavity. The body of the conductivity sensor can be made of any suitable material. The conductivity sensor body may be made of a material that is substantially impermeable to the aerosol-forming liquid substrate. The body of the conductivity sensor can be made of electrically insulating material. For example, suitable electrical insulating materials include glasses, plastics and ceramic materials. As used herein, electrical insulating material refers to a material having a volume resistivity at 20°C greater than about 1×10 ⁶ ohm⋅m, typically from about 1×10 ⁹ ohm⋅m to about 1×10 ²¹ ohm⋅m .

Inductive conductivity sensors can be located at any suitable location in the aerosol generating system. Preferably, inductive conductivity sensors are located in the liquid storage portion. Preferably, inductive conductivity sensors are located in the liquid storage portion, and an aerosol-forming liquid substrate held in the liquid storage portion may flow through the internal cavity between the first and second electrodes.

In these third preferred embodiments, the control electronics may be configured to apply an alternating voltage to the conductivity sensor with a frequency of from about 1 MHz to about 100 MHz.

In these third preferred embodiments, the first electrode winding may have any suitable number of turns. The second electrode winding may have any suitable number of turns. Preferably, the winding of the second electrode has the same number of turns as the winding of the first electrode. The winding of the first electrode may have any suitable shape. For example, the winding of the first electrode may be a helical coil or a toroid. The winding of the second electrode may have any suitable shape. For example, the winding of the second electrode may be a helical coil or a toroid. Preferably, the winding of the second electrode has the same shape as the winding of the first electrode. Particularly preferably, the winding of the first electrode and the winding of the second electrode are identical toroids.

The control electronics control the supply of power from the power supply to the electrodes of the conductivity sensor. The power supplied to the conductivity sensor is in the form of alternating voltage. An alternating voltage may be applied to the electrodes of the conductivity sensor at any suitable frequency.

The control electronics are configured to determine the concentration of nicotine in the aerosol-forming liquid substrate based on one or more measurements from the conductivity sensor. The control electronics may be configured to determine the nicotine concentration in any suitable manner. In one example, a predetermined functional relationship between electrical conductivity and nicotine concentration may be known. A suitable algorithm may be stored in a memory of the control electronics, and the control electronics may be configured to calculate nicotine concentration by applying conductivity measurements to the stored algorithm. In another example, predetermined conductivity values of the aerosol-forming substrate for known nicotine concentrations may be stored in a lookup table in the control electronics memory, and the conductivity measurements may be compared with the stored conductivity values to determine the nicotine concentration of the aerosol-forming substrate. Predetermined conductivities of the aerosol-generating substrate for known nicotine concentrations can be determined by calibration, typically performed at the factory before the aerosol-generating system is made available to the user for use.

It will 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 include stored nicotine concentration values in a lookup table stored in a memory of the control electronics. For example, in some embodiments of the present invention, determining the nicotine concentration in a liquid aerosol-forming substrate involves using electrical conductivity measurements to determine the specific power to be applied to the atomizer. In these embodiments, determining the power to be supplied to the atomizer using electrical conductivity measurements is based on a predetermined relationship between the nicotine concentration and the electrical conductivity of the aerosol-forming liquid substrate.

In some embodiments, the control electronics are further configured to control the supply of power from the power supply to the atomizer to atomize the liquid aerosol substrate based on the determined concentration of nicotine in the liquid aerosol substrate. Advantageously, this may allow the aerosol generating system to control the amount of aerosol generated by the system based on the concentration of nicotine in the aerosol generating substrate.

Preferably, the control electronics are configured to control the supply of power from the power supply to the atomizer for atomizing the liquid aerosol-forming substrate based on a determined concentration of nicotine in the liquid aerosol-forming substrate by comparing the determined nicotine concentration to a predetermined threshold value. The control electronics may be further configured to apply a first power to the atomizer when the determined nicotine concentration is equal to or below a predetermined threshold value. The control electronics may be further configured to apply a second power to the atomizer that is less than the first power when the determined nicotine concentration exceeds a predetermined threshold value. Such a configuration can generate a relatively large amount of aerosol during user use when the determined nicotine concentration is relatively low, and can generate a relatively small amount of aerosol when the determined nicotine concentration is relatively high. Changing the amount of aerosol generated during user application may change the amount of nicotine delivered to the user during user application. Advantageously, this may enable the aerosol generating system to deliver a stable amount of nicotine to the user during use by the user, regardless of the concentration of nicotine in the liquid aerosol-generating substrate.

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 the memory of the control electronics, wherein each power setting is associated with a particular predetermined nicotine concentration and conductivity, and the control electronics may be configured to compare the conductivity measurement with the stored conductivity values in the lookup table and submit supplies power from the power supply to the atomizer based on a power setting associated with a stored conductivity value that corresponds to a conductivity measurement.

The control electronics may be configured to control the power supplied from the power supply to the atomizer continuously. The control electronics may be configured to control power supplied from the power supply to the atomizer according to a function of electrical conductivity. The predefined algorithm may be stored in the control electronics memory, and conductivity measurements may be applied to the predefined algorithm to determine the power to be supplied from the power supply to the atomizer.

The control electronics may be configured to supply power from the power supply to the electrodes of the conductivity sensor at any appropriate time. Preferably, the control electronics are configured to supply power from the power supply to the electrodes of the conductivity sensor before power is supplied from the power supply to the atomizer for atomizing the liquid substrate forming an aerosol. Advantageously, this may allow the control electronics to control the power supplied from the power supply to the atomizer based on a specific nicotine concentration in the aerosol-forming substrate.

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

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 be further configured to adjust the nicotine concentration determination based on one or more temperature measurements from the temperature sensor.

The temperature sensor may be any suitable type of temperature sensor for measuring the temperature of the liquid substrate forming the aerosol. Suitable temperature sensor types include, but are not limited to, thermocouples, thermistors, and RTDs.

The temperature sensor may be positioned to measure the temperature of the liquid substrate forming the aerosol. The temperature sensor may be located at any suitable location relative to the conductivity sensor. Preferably, the temperature sensor is located on or around the conductivity sensor to minimize the temperature difference between the liquid aerosol-forming substrate measured by the temperature sensor and the liquid aerosol-forming substrate measured by the conductivity sensor. The temperature sensor may be located in the liquid storage portion. The temperature sensor may be located on or around the atomizer. A temperature sensor may be located 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 nebulizer includes a temperature sensor.

The control electronics may adjust the determination of nicotine concentration based on temperature measurements in any suitable manner.

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

In another example, predetermined conductivity values of the aerosol-forming substrate at specific temperatures for known nicotine concentrations may be stored in a lookup table in the control electronics memory, and conductivity and temperature measurements may be compared with the stored conductivity and temperature values to determine the nicotine concentration of the aerosol-forming substrate. .

In some embodiments, the aerosol generating system may include a heater. The heater may be positioned to heat the aerosol-forming liquid 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 aerosol-forming liquid substrate from the liquid storage portion to a predetermined temperature.

The heater may be located at any suitable location relative to the conductivity sensor. Preferably, the heater is located on 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 measured by the conductivity sensor. The heater may be located in the liquid storage portion. The heater may be located on or around the atomizer. The heater may be located between the liquid storage portion and the atomizer. Typically, the heater is located upstream of the conductivity sensor such that the heater can heat the aerosol-forming liquid substrate to a predetermined temperature before the aerosol-forming liquid substrate reaches the conductivity sensor. In some embodiments, the heater is a separate component from the atomizer. In some embodiments, the nebulizer includes a heater.

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

The predetermined temperature may be any suitable temperature. Typically, the predetermined temperature is higher than the expected ambient temperature, so that the ambient temperature does not affect the temperature of the aerosol-forming liquid 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 substrate forming the aerosol.

In embodiments comprising a heater for heating the aerosol-forming substrate to a predetermined temperature, there may be no need to provide a temperature sensor for measuring the temperature of the liquid aerosol-forming substrate, since it may be reasonable to assume that the temperature of the liquid aerosol-forming substrate measured by the conductivity sensor equal to a predetermined temperature.

The aerosol generating system may include a housing. The housing may be made of any suitable material or combination of materials. Suitable materials include, but are not limited to, aluminum, polyetheretherketone (PEEK), polyimides such as Kapton®, polyethylene terephthalate (PET), polyethylene (PE), high density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), epoxy resins, polyurethane resins, vinyl resins, liquid crystal polymers (LCP) and modified LCP such as graphite fiber or glass fiber LCP.

The housing may form a liquid storage portion. The liquid storage portion may be of any suitable shape and size to hold a sufficient aerosol-forming liquid substrate for multiple uses by the user. For example, the liquid storage portion may have sufficient capacity to allow continuous generation of the aerosol for a period of approximately six minutes, or for a period of multiples of six minutes. In another example, the liquid storage portion may have sufficient capacity to allow a predetermined number of puffs or individual activations of the nebulizer.

In some embodiments, a porous carrier material may be provided in the liquid storage portion. The aerosol-forming liquid substrate may be sorbed or otherwise loaded into a porous carrier material. The porous carrier material can be made from any suitable absorbent plug or body. For example, the absorbent plug or body may be metal or plastic foam, polypropylene, terylene, nylon fibers, or ceramic.

The aerosol generating system may further comprise a liquid transfer element. The liquid transfer member may be configured such that, in use, the aerosol-forming liquid substrate is transferred by capillary action along the liquid transfer member from the liquid storage portion to the atomizer. In embodiments in which the liquid storage portion comprises a porous carrier material, the liquid transfer member is configured to move a liquid aerosol-forming substrate from the porous carrier material to the atomizer. The liquid transfer element may comprise capillary material. A capillary material is a material that actively moves liquid from one end of the material to the other. The capillary material may be advantageously oriented in the liquid storage portion so as to transport the aerosol-forming liquid substrate toward the nebulizer.

The liquid transfer element may comprise any suitable material or combination of materials that are suitable for transporting an aerosol-forming liquid substrate along its length. The liquid transfer element may be formed from a porous material, but this is not required. The liquid transfer element may be formed from a material having a fibrous or sponge structure. The liquid transfer element preferably comprises a bank of capillaries. For example, the liquid transfer element may comprise a plurality of fibers or filaments or other tubes with thin channels. The liquid transfer element may comprise a sponge-like or foam-like material. Preferably, the structure of the liquid transfer element defines a plurality of small channels or tubes through which the aerosol-forming liquid substrate can be transferred by capillary action. The specific material or materials preferred will depend on the physical properties of the liquid substrate forming the aerosol. Examples of suitable capillary materials include sponge or foam material, ceramic or graphite based materials in the form of fibers or sintered powders, foamed metal or plastic material, fiber material, for example made from spun or extruded fibers such as cellulose acetate, polyester or bonded polyolefin, polyethylene , terylene or polypropylene fibers, nylon fibers, ceramics, glass fibers, glass-ceramic fibers, carbon fibers, metal fibers from medical grade stainless steel alloys such as austenitic grade 316 stainless steel and martensitic grade 440 and 420 stainless steels. The fluid transfer element can have any suitable capillarity in order to be used with different physical properties of the liquid. The liquid aerosol-forming substrate has physical properties, including, but not limited to, viscosity, surface tension, density, thermal conductivity, boiling point, and vapor pressure, that enable movement of the liquid aerosol-forming substrate through the liquid transfer element. The liquid transfer element may be formed from a heat-resistant material. The liquid transfer element may comprise a plurality of fiber strands. The plurality of fiber strands may be generally aligned along the length of the fluid transfer element.

In embodiments in which the liquid storage section comprises a porous media material, the porous media material and the liquid transfer member may comprise the same material. Preferably, the porous carrier material and the liquid transfer element comprise different materials.

The atomizer may be any suitable type of atomizer. For example, the nebulizer may be an acoustic nebulizer. An acoustic nebulizer can release volatile compounds from an aerosol-forming substrate by moving the aerosol-forming substrate through a plurality of nozzles using vibrations, typically at ultrasonic frequencies. In another example, the atomizer may be a thermal atomizer. A thermal nebulizer can release volatile compounds from an aerosol-forming substrate by heating the aerosol-forming substrate.

In some embodiments, the nebulizer includes a conductivity sensor. In these embodiments, the atomizer may include one or more electrically conductive elements. The one or more conductivity sensor electrodes may comprise one or more electrically conductive elements of the atomizer. Advantageously, combining a nebulizer and a conductivity sensor can reduce the number of components of an aerosol generating system, reducing cost and manufacturing complexity.

In some preferred embodiments, the nebulizer is a thermal nebulizer. The thermal nebulizer may be an electric heater. The thermal atomizer may contain one or more heating elements. Preferably, the thermal atomizer contains a plurality of heating elements.

In some particularly preferred embodiments, the atomizer is a thermal atomizer comprising a plurality of heating elements, and each of the conductivity sensor electrodes comprises a thermal atomizer heating element. In these particularly preferred embodiments, the control electronics may be further configured to supply first power from the power supply to the conductivity sensor electrodes for measuring the conductivity of the aerosol-forming liquid substrate; and supplying second power from the power supply to a plurality of heating elements of the atomizer to atomize the liquid substrate to form an aerosol. 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 aerosol-forming liquid 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 aerosol-forming liquid substrate.

The thermal atomizer may include a resistive heating coil. The thermal atomizer may contain a plurality of resistive heating coils.

The thermal atomizer may comprise a resistive heating grid. The thermal atomizer may contain a plurality of resistive heating grids.

The resistive heating grid may contain a plurality of electrically conductive filaments. The electrically conductive threads may be substantially flat. As used herein, "substantially flat" means formed in a single plane and not wrapped around or otherwise adapted to conform to a curved or other non-flat shape. The flat heating grid can be easily handled during manufacture and provides a strong structure.

The electrically conductive threads may define spaces between the threads, and these spaces may have a width of from about 10 micrometers to about 100 micrometers. Preferably, the filaments create capillary action in the interstices such that, when used, the aerosol-forming liquid substrate is drawn into the interstices, increasing the contact area between the heater assembly and the liquid.

The electrically conductive filaments can form a mesh ranging from about 160 US mesh to about 600 US mesh (+/- 10%) (i.e., from about 160 to about 600 threads per inch (+/- 10%)) . The width of the spaces is preferably from about 75 micrometers to about 25 micrometers. The percentage of open mesh area, which is the ratio of the area of the interstices to the total area of the mesh, is preferably from about 25 percent to about 56 percent. The mesh can be formed using various types of woven or lattice structures. The electrically conductive threads can be a matrix of threads arranged parallel to each other.

The electrically conductive filaments may have a diameter of from about 8 micrometers to about 100 micrometers, preferably from about 8 micrometers to about 50 micrometers, and more preferably from about 8 micrometers to about 39 micrometers.

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

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

The electrical resistance of the resistive heating grid is preferably from about 0.3 to about 4 ohms. More preferably, the electrical resistance of the grid is from about 0.5 to about 3 ohms, and more preferably about 1 ohm.

In embodiments in which the thermal atomizer includes a resistive heating coil, the coil pitch is preferably from about 0.5 millimeters to about 1.5 millimeters, and most preferably about 1.5 millimeters. Coil pitch refers to the distance between adjacent turns of a coil. The coil may contain less than six turns and preferably has less than five turns. The coil may be formed from electrically resistive wire with a diameter of from about 0.10 millimeters to about 0.15 millimeters, preferably about 0.125 millimeters. The electrically resistive wire is preferably made 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, cobalt, chromium, aluminum, titanium, zirconium, hafnium, niobium, molybdenum, tantalum, tungsten, tin, gallium, manganese and iron-containing alloys, as well as superalloys based on nickel, iron, cobalt, stainless steel, Timetal®, alloys based on iron and aluminum, and alloys based on iron, manganese and aluminum. The resistive heating coil may also comprise metal foil, such as aluminum foil, which is shaped as a strip.

In embodiments in which the thermal atomizer includes a resistive heating coil, the resistive heating coil may be wrapped around the material to move liquid.

The power supply may include any suitable type of power supply. For example, the power supply may contain a battery. The power supply 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 supply may contain another type of charge storage device, such as a capacitor. The power supply may require recharging. The power supply may have a capacity that allows sufficient energy to be stored to operate the aerosol generating system for multiple uses by the user. For example, the power supply may have sufficient capacity to enable continuous generation of the aerosol for a period of approximately six minutes, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to allow a predetermined number of puffs or individual activations of the atomizer to occur.

The control electronics may comprise a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit (ASIC) or other electronic circuit capable of providing control. The control electronics may contain additional electronic components. The control electronics are configured to regulate the power supply to the heater assembly. Power may be supplied to the heater assembly continuously once the system is activated, or may be supplied intermittently, such as from puff to puff. Power may be supplied to the heater assembly in the form of pulses of electrical current.

The control electronics may advantageously comprise a DC to AC converter, which may include a Class D or Class E power amplifier. The DC to AC converter may enable the control electronics to supply an alternating voltage from the power supply to the conductivity sensor.

The conductivity sensor may be located at any suitable position in the aerosol generating system.

In some embodiments, the conductivity sensor is located in the liquid storage portion. In particular, an inductive conductivity sensor may be located in the liquid storage portion.

In some embodiments, the system comprises one or more porous carrier materials for holding, and optionally moving, a liquid aerosol-forming substrate. When the system contains a porous carrier material that contains an aerosol-forming liquid substrate, one or more conductivity sensor electrodes may be located on or around the porous carrier material. One or more conductivity sensor electrodes may be positioned in contact with a porous carrier material. One or more electrodes of the conductivity sensor may be positioned in contact with the end of the porous carrier material.

In some embodiments, the conductivity sensor is located between the liquid storage portion and the atomizer. In these embodiments, at least two conductivity sensor electrodes may be located on or around the flow path of the aerosol-forming liquid substrate between the liquid storage portion and the atomizer.

In some embodiments, the nebulizer may include a conductivity sensor. In other words, at least two conductivity sensor electrodes may be included in the atomizer. In some preferred embodiments, the atomizer comprises a plurality of elements, such as heating elements, and at least one of the at least two conductivity sensor electrodes may comprise a nebulizer element. In some embodiments, each conductivity sensor electrode includes an atomizer element.

In embodiments in which the atomizer includes a conductivity sensor, the control electronics may be coupled to the atomizer and the conductivity sensor in any suitable manner. The control electronics may include circuitry for generating the aerosol and circuitry for measuring conductivity. The aerosol generating circuitry may control the supply of power to the elements of the atomizer to atomize the liquid substrate to form the aerosol. The conductivity measurement circuitry may control the application of power to the electrodes of the conductivity sensor to measure the electrical conductivity of the liquid substrate forming the aerosol.

In some embodiments, the control electronics comprise separate aerosol generation circuitry and conductivity measurement circuitry. In these embodiments, each nebulizer element, which is also configured as a conductivity sensor electrode, may include at least one electrical contact electrically connecting the element to the aerosol generating circuitry and at least one electrical contact electrically connecting the element to the conductivity sensing circuitry. Preferably, each atomizer element, which is also configured as a conductivity sensor electrode, includes two electrical contacts electrically connecting the element to the aerosol generating circuitry and one electrical contact electrically connecting the element to the conductivity sensing circuitry.

In some embodiments, the control electronics comprise general aerosol generation circuitry and conductivity measurement circuitry. In these embodiments, each nebulizer element, which is also configured as a conductivity sensor electrode, may include at least one electrical contact electrically connecting the element to the aerosol generating circuitry and the conductivity measurement circuitry. Preferably, each atomizer element, which is also configured as a conductivity sensor electrode, includes two electrical contacts electrically connecting the element to the aerosol generating circuit and the conductivity measuring circuit.

In some embodiments, the aerosol generating system includes a device and a cartridge. The cartridge may be configured to be placed in and removed from the device. Typically, the cartridge contains a liquid storage portion and the device contains a power supply and control electronics. In these embodiments, the conductivity sensor may be provided either in the device or in the cartridge. In some embodiments, a nebulizer is provided in the device. In some preferred embodiments, the atomizer is provided in a cartridge.

According to the present invention, there is provided an aerosol generating system as described above, the aerosol generating system includes a device part and a cartridge part, the cartridge part being configured to be accommodated in and removed from the device part. The device part contains the power supply and control electronics, and the cartridge part contains the liquid storage part, the atomizer and the conductivity sensor.

Advantageously, providing the aerosol generating system with a conductivity sensor either in the device or in the cartridge may enable the manufacturer to standardize the manufacture of the cartridges and the manufacture of the devices regardless of the aerosol generating substrate that needs to be retained in the liquid storage portion of the cartridge or device. In other words, providing an aerosol generating system with a conductivity sensor may enable a manufacturer to produce identical cartridges and identical devices regardless of the aerosol-generating substrate that must be retained in the liquid storage portion of the cartridge or device. This standardization can reduce the cost and complexity of cartridge and device manufacturing.

In some embodiments, a conductivity sensor is provided in the device. Advantageously, providing a 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, reducing the cost and complexity of manufacturing the cartridge.

In some embodiments, the conductivity sensor is provided in a cartridge. In some preferred embodiments, in which the atomizer is a thermal atomizer comprising a plurality of heating elements and each conductivity sensor electrode is formed from a heating element of the atomizer, the conductivity sensor may be provided in a cartridge. In these preferred embodiments, the thermal atomizer is provided in a cartridge. Such a cartridge is usually called a “cartomizer”. Cartomizers can provide the ability to maintain a high level of hygiene in an aerosol generating system because components that come into contact with the aerosol-generating substrate can be regularly replaced and the user is not exposed to components that come into contact with the aerosol-generating substrate.

According to the present invention, there is provided a cartridge for an aerosol generating system, the cartridge comprising: a liquid storage portion for holding a liquid aerosol-generating substrate; a sprayer in fluid communication with the liquid storage portion; and a conductivity sensor arranged to measure the electrical conductivity of the aerosol-forming liquid substrate from the liquid storage portion.

In some particularly preferred embodiments, the cartridge conductivity sensor comprises two electrodes, a first electrode and a second electrode, located in a liquid storage portion, each electrode defining a winding wherein the first electrode is positioned to induce current in the second electrode when the first electrode is supplied with AC voltage. In other words, the cartridge may contain an inductive conductivity sensor as described above.

The cartridge may have a simple design. The cartridge may have a housing defining a liquid storage portion. The cartridge body is preferably a rigid body containing a liquid impermeable material. As used herein, "rigid housing" means a housing that is self-supporting. The device may also have a housing. The device housing is preferably a rigid housing. The cartridge body and the device body can be made of the same material. The device may have a cavity to accommodate the cartridge.

When the cartridge contains an atomizer, the device may include electrical contacts for electrically connecting the power supply and control electronics in the atomizer device in the cartridge. When the cartridge contains a conductivity sensor, the device's electrical contacts may electrically connect the control electronics and power supply in the device to the conductivity sensor in the cartridge.

The aerosol generating system may include a mouthpiece through which a user can puff to obtain an aerosol generated by the aerosol generating system. In some systems containing devices and cartridges, the device contains a mouthpiece. In some systems containing devices and cartridges, the cartridge contains a mouthpiece. Advantageously, providing the mouthpiece on the cartridge can help maintain a high level of hygiene in the system since the cartridge can be disposable and replaced more frequently than the device.

It will be understood that features described with respect to one embodiment may also be applied to other embodiments. For example, the features described with respect to a cartridge may be equally applicable to an aerosol generating system, and in particular to an aerosol generating system including a cartridge.

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

in fig. 1a is a schematic diagram of an aerosol generating system comprising an aerosol generating device and a cartridge insertable into the aerosol generating device;

in fig. 1b is a schematic representation of the aerosol generating system shown in FIG. 1a, in which the cartridge is housed in an aerosol generating device;

in fig. 2 is a schematic illustration of the end of a liquid transfer element of an aerosol generating system, wherein the end of the liquid transfer element has a nebulizer and a conductivity sensor according to an embodiment of the present invention;

in fig. 3 is a schematic illustration of a nebulizer and conductivity sensor in accordance with another embodiment of the present invention;

in fig. 4 is a schematic illustration of the end of a liquid transfer element of an aerosol generating system, the end of the liquid transfer element having a nebulizer and a conductivity sensor according to another embodiment of the present invention;

in fig. 5 is a schematic view of the end of the liquid transfer element shown in FIG. 4, including an electrical connection between the nebulizer and the conductivity sensor and the control electronics of the aerosol generating device;

in fig. 6a. 6b, 6c and 6d show schematic representations of elements of an embodiment of control electronics suitable for use with the atomizer and conductivity sensor shown in FIG. 4;

in fig. 7 is a schematic diagram of a four-point conductivity sensor according to another embodiment of the present invention;

in fig. 8 is a schematic view of the first side of the four-point conductivity sensor shown in FIG. 7;

in fig. 9 is a schematic diagram of an inductive conductivity sensor according to another embodiment of the present invention; And

in fig. 10 is a schematic cross-sectional view through the length of the inductive conductivity sensor shown in FIG. 9.

In fig. 1a and 1b are schematic diagrams of an exemplary aerosol generating system comprising a cartridge in which a conductivity sensor may be provided, in accordance with embodiments of the present invention. Fig. 1a and 1b respectively represent FIGS. 1a and 1d from the publication of the international patent application number WO 2015/117702 A1.

In fig. 1a shows a schematic view of an aerosol generating device 10 and a separate cartridge 20, which together form an aerosol generating system.

The cartridge 20 contains an aerosol-forming substrate and is configured to be placed in a cavity 18 within the device. The cartridge 20 must be replaceable by the user when the aerosol-forming substrate provided in the cartridge is depleted. In fig. 1a shows the cartridge 20 just before insertion into the device, with arrow 1 shown in FIG. 1a indicates the insertion direction of the cartridge.

The cartridge 20 includes a generally circular cylindrical body 24 that is sized and shaped to fit within the cavity 18. The body contains a capillary material (not shown) that is impregnated with a liquid aerosol-forming substrate. In this example, the aerosol-forming substrate contains 39% by weight glycerin, 39% by weight propylene glycol, 20% by weight water and flavorings, and 2% by weight nicotine. The capillary material is a material that actively conducts liquid from one end to the other, and can be made of any suitable material. In this example, the capillary material is made of polyester.

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

The heater assembly 30 is covered with a removable cover 26. The cover includes a liquid-impervious sheet of plastic that is adhered to the heater assembly but which can be easily removed. A tab is provided on the side of the cover to allow the user to grasp the cover when removing it. It will now be apparent to one skilled in the art that while bonding is described as a method of attaching an impervious sheet of plastic to the heater assembly, other methods known to those skilled in the art may be used, including heat sealing or ultrasonic welding, provided that the coating can be easily removed by the consumer.

The aerosol generating device 10 is portable and has a size comparable to that of a traditional cigar or cigarette. The device 10 includes a main body 11 and a mouthpiece 12. The main body 11 contains a battery 14, such as a lithium iron phosphate battery, control electronics 16, and a cavity 18. The mouthpiece 12 is connected to the main body 11 by a hinge joint 21 and is movable between open position, which is shown in Fig. 1, and the closed position, which is shown in FIG. 1b. The mouthpiece portion 12 is positioned in an open position to allow insertion and removal of cartridges 20 and is positioned in a 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 inlet holes 13 and an outlet hole 15. In use, the user draws or puffs on the outlet hole to draw air through the air inlet holes 13 through the mouthpiece portion into the outlet hole 15 and then into the mouth or lungs of the user. Internal baffles 17 are provided to force air to flow through the mouthpiece portion 12 past the cartridge 20, as will be described.

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

Cartridge 20 is inserted into cavity 18 and cover 26 is removed from the cartridge. In this position, the electrical connectors are opposite the electrical contacts on the cartridge, as will be described. The mouthpiece portion 12 is then moved to the closed position.

In fig. 1b shows the system with the mouth piece 12 in a closed position. The mouth piece 12 is held in the closed position by a locking mechanism (not shown).

The mouthpiece 12, in the closed position, holds the cartridge in electrical contact with the electrical connectors 19 so that a good electrical connection is maintained during use regardless of the orientation of the system. The mouthpiece 12 may include an annular elastomeric element that contacts the surface of the cartridge and is compressed between the rigid mouthpiece body member and the cartridge when the mouthpiece 12 is in the closed position. This ensures that a good electrical connection is maintained despite manufacturing tolerances. Of course, other mechanisms may be used to maintain a good electrical connection between the cartridge and the device.

In fig. 2 is a schematic diagram of an exemplary nebulizer and conductivity sensor 100 for an aerosol generating system, such as the aerosol generating system shown in FIG. 1a and 1b. The atomizer and conductivity sensor 200 are configured as a two-point conductivity sensor.

In fig. 2 is a top view of an integrated atomizer and cartridge conductivity sensor 100 housed in the aerosol generating device and electrically coupled to the device control electronics 110. The cartridge includes a liquid storage portion comprising a generally cylindrical body of capillary material 102 in which a liquid substrate forming an aerosol is retained. The atomizer and conductivity sensor 100 shown in FIG. 2 are located above and in contact with the end of the generally cylindrical body of capillary material 102. The capillary material 102 is configured such that the aerosol-forming liquid substrate contained in the capillary material is drawn by capillary action toward the end of the capillary body in contact with the atomizer and conductivity sensor 100 .

The atomizer and conductivity sensor 100 include two electrodes, a first electrode 104 and a second electrode 106. Each of the first electrode 104 and the second electrode 106 contains a resistive heating grid that contains 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 wide enough to electrically isolate the first electrode 104 from the second electrode 106 on the capillary material. 102 when there is no aerosol-forming liquid substrate in the capillary material 102.

The first and second electrodes 104, 106 are configured such that the aerosol-forming liquid substrate at the end of the capillary body comes into contact with the first and second electrodes 104, 106.

In the embodiment shown in FIG. 2, the first and second electrodes 104, 106 are electrically coupled to the control electronics of an aerosol generating device (not shown), such as the aerosol generating device shown in FIG. 1a and 1b. The control electronics of the aerosol generating device is configured to control the supply of power from the device's power supply to the first electrode 104 and the second electrode 106.

In this embodiment, the control electronics of the aerosol generating device includes a separate conductivity measurement circuit 111 and a circuit 112 for generating the aerosol. Each of the conductivity measurement circuit 111 and the aerosol generating circuit 112 includes electrical contacts in the form of resilient pin contacts to provide a reliable electrical connection between the control electronics of the aerosol generating device and the first and second electrodes 104, 106 when the cartridge is positioned in the device.

Each of the first and second electrodes 104, 106 is electrically connected to the conductivity measuring circuit 111 by one electrical contact. Accordingly, the conductivity measurement circuit contains two electrical contacts, one for each electrode 104, 106.

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

Each of the first and second electrodes 104, 106 is also separately electrically connected to the aerosol generating circuit 112 by two electrical contacts. Each of the first and second electrodes 104, 106 is electrically connected to a first electrical contact at a first end of the electrode and electrically connected to a second electrical contact at a second end of the electrode opposite the first end. The aerosol generating circuit 112 is configured to apply a voltage between the first and second electrical contacts to each of the first and second electrodes 104, 106. The voltage across 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 across the second electrode 204 between the first and second electrical contacts drives a current through the second electrode 204 drives 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 a direct current between two electrical contacts of each electrode 104, 106 in the form of pulses. The aerosol generating circuit 112 is configured to change the duty cycle of the DC pulses to change the temperature of the electrodes 104, 106.

The conductivity measurement circuit 111 is configured to supply a first power to the first and second electrodes 104, 106, and the aerosol generating circuit 112 is configured to provide a second power to the first and second electrodes 104, 106. Preferably, the first power is not sufficient to heat the heater filaments of the electrodes 104 , 106 and evaporation of the liquid substrate, forming an aerosol, in contact with the heater filaments. The second power is sufficient to heat the heater filaments of the first and second electrodes 104, 106 to vaporize the aerosol-forming liquid substrate in contact with the heater filaments. The aerosol generating circuit 112 is configured to vary the second power based on the electrical conductivity of the aerosol-forming liquid substrate determined by the conductivity measurement circuit 111, which provides an indication of the nicotine concentration in the aerosol-forming liquid substrate.

In this embodiment, the conductivity measuring circuit 111 is configured to apply first power to the first and second electrodes 104, 106 and measure the electrical conductivity of the liquid aerosol-forming substrate located in the cavity 108 before the aerosol generating circuit 112 applies the second power to the first and second electrodes 104, 106 for heating the liquid substrate to form an aerosol. This allows the aerosol generating circuit 112 to adjust the second power in response to a certain nicotine concentration of the aerosol-generating liquid substrate prior to each aerosol generating cycle, such as each time a user takes a puff on the aerosol generating system to obtain an aerosol from the system.

In fig. 3 shows a schematic diagram of another exemplary atomizer and conductivity sensor 200 for an aerosol generating system. The atomizer and conductivity sensor 200 are designed as a two-point conductivity sensor.

In this embodiment, the cartridge (not shown) includes a liquid moving member 202 in the form of a wick having at least one end in contact with a liquid aerosol-forming substrate in the liquid storage portion of the cartridge. The combined atomizer and conductivity sensor 200 of this embodiment includes two coil-type electrodes 204, 206 located on a liquid transfer material portion 202 outside the liquid storage portion. The liquid transfer material 202 is arranged to draw the aerosol-forming liquid substrate from the liquid storage portion to the first and second coil electrodes 204, 206 of the combined atomizer and conductivity sensor 200. Each coil electrode 204, 206 includes a resistive heating wire wound concentrically in a spiral around a portion of the wick outside the liquid storage portion. Two coil electrodes 204, 206 wound together around a wick in the same direction and containing the same number of turns are substantially identical. The second coil 206 is offset from the first coil 204 along the wick such that a cavity 208 is provided between the respective turns of the first and second coils 204, 206. The cavity between the corresponding turns of the first and second coils 204, 206 is such that the aerosol-forming liquid substrate in the wick can be drawn into the cavity 208 and located between the coil electrodes 204, 206.

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

In the embodiment shown in FIG. 3, the first and second coil electrodes 204, 206 are electrically coupled to the control electronics of an aerosol generating device (not shown), such as the aerosol generating device shown in FIG. 1a and 1b. The control electronics of the aerosol generating device are configured to control the supply of power from the device's power supply to the first electrode 204 and the second electrode 206.

In this embodiment, the control electronics of the aerosol generating device includes a general conductivity measurement circuit 211 and an aerosol generating circuit 212. The conductivity measurement circuit 211 and the aerosol generation circuit 212 contain common electrical contacts.

Each of the first and second coil electrodes 204, 206 is electrically coupled to the aerosol generating circuit 212 by two electrical contacts, one electrical contact at each end of the coil electrode. The aerosol generating circuit 212 is configured to apply a voltage between contacts at opposite ends of each coil such that a voltage is established at each of the first and second electrodes 204, 206. The voltage at the first electrode 204 drives a current through the first electrode 204 to heat the electrode. The voltage across 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 through each of the first and second electrodes 204, 206 in the form of pulses. The aerosol generating circuit 212 is configured to vary the duty cycle of the DC pulses to vary the temperature of the first and second electrodes 204, 206.

In this embodiment, conductivity measurement circuit 211 shares electrical contacts with aerosol generation circuit 212. Each of the first and second coil electrodes 204, 206 is electrically connected to the conductivity measuring circuit 211 by one electrical contact. The conductivity measuring circuit 211 is electrically connected to the first coil electrode 204 through an electrical contact at the first end of the first coil electrode 204 and electrically connected to the second coil electrode 206 through an electrical contact at the second end of the second coil electrode 206, which is the outermost end of the second coil electrode 206 from the first end of the first coil electrode 204. Accordingly, the conductivity measurement circuit 211 includes two electrical contacts, one for each coil electrode 204, 206.

The conductivity measuring circuit 211 is configured to apply an alternating voltage between two electrical contacts of the conductivity measuring circuit 211, which in turn establishes an alternating voltage between the first and second coil electrodes 204, 206. The alternating voltage between the first and second coil electrodes 204, 206 triggers alternating current through the cavity 208 between the first and second electrodes 204, 206, through the aerosol-forming liquid substrate located in the cavity 208. The conductivity measurement circuit 211 is further configured to measure the current between the first and second coil electrodes 204, 206 and determine the electrical conductivity of the liquid substrate , forming an aerosol located in the cavity 208, based on the measured current. The electrical conductivity of the liquid aerosol substrate provides an indication of the concentration of nicotine in the liquid aerosol substrate.

The conductivity measurement circuit 211 is configured to apply a first power to the first and second coil electrodes 204, 206, and the aerosol generating circuit 212 is configured to provide a second power to the first and second electrodes 204, 206. Preferably, the first power is not sufficient to heat the coil electrodes 204 , 206 and evaporation of the liquid substrate, forming an aerosol, in contact with the coil electrodes. The second power is sufficient to heat the first and second coil electrodes 204, 206 to vaporize the aerosol-forming liquid substrate in contact with the coil electrodes. The aerosol generating circuit 212 is configured to vary the second power based on the electrical conductivity of the aerosol-forming liquid substrate determined by the conductivity measurement circuit 211, which provides an indication of the nicotine concentration in the aerosol-forming liquid substrate.

It will be understood that in other embodiments, the first and second coil electrodes 204, 206 may be separately electrically coupled to the conductivity measurement circuitry and aerosol generation circuitry of the aerosol generating device, similar to the first and second electrodes 104, 106 of the atomizer and conductivity sensor described above. in relation to fig. 2.

In fig. 4 and 5 show schematic diagrams of another exemplary nebulizer and conductivity sensor 300 for an aerosol generating system, such as the aerosol generating system shown in FIG. 1a and 1b. The atomizer and conductivity sensor 300 are designed as a four-point conductivity sensor.

In fig. 4 is a top view of the combined atomizer and cartridge conductivity sensor 300, and FIG. 5 is a top view of the cartridge housed in the aerosol generating device and electrically coupled to control electronics 310 of the device.

The cartridge includes a liquid storage portion comprising a generally cylindrical body of capillary material 302 in which a liquid substrate forming an aerosol is retained. The atomizer and conductivity sensor 300 shown in FIG. 4 and 5 are located above and in contact with the end of the generally cylindrical body of capillary material 302. The capillary material 302 is configured such that the aerosol-forming liquid substrate contained in the capillary material is drawn by capillary action toward the end of the capillary body in contact with the atomizer and conductivity sensor 300 .

The atomizer and conductivity sensor 300 include 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 that contains a plurality of electrically conductive heater filaments.

The pair of outer electrodes 304 are spaced such that there is an outer cavity 308 between the outer electrodes 304. The outer cavity 308 between the outer electrodes 304 is wide enough to electrically isolate the outer electrodes 304 from each other on the capillary material 302 when there is no liquid substrate in the capillary material 302 , forming an aerosol.

A pair of inner electrodes 306 are located between a pair of outer electrodes 304, in an outer cavity 308. A pair of inner electrodes 306 are sufficiently spaced from a pair of outer electrodes 304 to electrically isolate the inner electrodes 306 from the outer electrodes 304 on the capillary material 302 when there is no liquid in the capillary material 302. aerosol-forming substrate. The pair of internal electrodes 306 are spaced apart such that an internal cavity 309 is provided between the internal electrodes 306. The internal cavity 309 between the internal electrodes 306 is wide enough to electrically isolate the internal electrodes 306 from each other on the capillary material 302 when there is no liquid substrate present in the capillary material 302 , forming an aerosol.

The aerosol-forming liquid substrate at the end of the capillary body in contact with the atomizer and conductivity sensor 300 comes into contact with the inner and outer electrodes 204, 206.

Providing four electrodes in such an arrangement allows the combined atomizer and conductivity sensor 300 of this embodiment to be used as a four-point conductivity sensor, as described in more detail below.

In fig. 5, the inner and outer electrodes 304, 306 are shown in electrical connection with the control electronics 310 of an aerosol generating device (not shown), such as the aerosol generating device shown in FIG. 1a and 1b. The control electronics 310 of the aerosol generating device is configured to control the supply of power from the device's power supply to the external electrodes 304 and the internal electrodes 306.

In this embodiment, the aerosol generating device control electronics 310 includes common conductivity measurement circuitry and aerosol generating circuitry, as described in more detail below with reference to FIG. 6. In this embodiment, the conductivity measurement circuit and the aerosol generating circuit comprise common electrical contacts in the form of resilient pin contacts to provide a reliable electrical connection between the control electronics 310 of the aerosol generating device and the internal and external electrodes 304, 306. It will be appreciated that in other embodiments, the aerosol generation circuit and the conductivity measurement circuit may comprise separate electrical contacts.

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

In fig. 6a-d schematically illustrate certain components of an exemplary embodiment of aerosol generating device control electronics 310 in connection with the combined atomizer and conductivity sensor shown in FIG. 4 and 5.

The control electronics are designed to operate in two different modes - conductivity measurement mode and heating mode. In conductivity measurement mode, an alternating voltage is applied between two outer electrodes 304 and a voltage is measured at the two inner electrodes 306. In the heating mode, a pulsed direct current is applied through each of the inner and outer electrodes 304, 306 separately to heat the electrode heater filaments and evaporate the aerosol-forming liquid substrate in contact with the heater filaments.

In this embodiment, the control electronics 310 generally includes a _DC power supply VDC, a microcontroller 320, and a plurality of transistor switches. Transistor switches are field-effect transistors (FETs) controlled by control electronics to supply power to the combined atomizer and conductivity sensor according to the conductivity mode and heating mode.

In fig. 6a-d, the first of the outer electrodes is shown as E ₁ , the second of the outer electrodes is shown as E ₄ , the first of the inner electrodes is shown as E ₂ and the second of the inner electrodes is shown as E ₃ . As shown in FIG. 6a, each electrode E ₁ -E ₄ is connected to the control electronics by two electrical contacts spaced at opposite ends of the electrode. Each electrode E ₁ -E ₄ is connected by a first electrical contact to the DC power supply via a first transistor switch T _1a -T _4a . Each electrode is further connected by a second electrical contact to a position between the second transistor switch T _1b -T _4b and the third transistor switch T _1c -T _4c . The first transistor switches T _1a -T _4a allow the control electronics to individually isolate each of the electrodes from the power supply when the transistors are off. The function of the second and third transistor switches T _1b -T _4b , T _1c -T _4c will be described in more detail below.

In conductivity measurement mode, the control electronics apply a high-frequency alternating switching voltage to the gate of each of the first and second transistors of the external electrodes T _1a , T _1b , T _4a , T _4b so that during one half cycle, transistors T _1a and T _4b are conducting, and transistors T _1b and T _4a are off, and during the other half cycle, transistors T _1b and T _4a are conducting and transistors T _1a and T _4b are off.

In fig. 4b shows the connection of the combined atomizer and conductivity sensor to the power supply in conductivity mode during the first half cycle in which transistors T _1a and T _4b are conducting. The arrangement shown in FIG. 4b may be considered to include a first control circuit that operates to provide a first periodic voltage drop across the external electrodes E ₁ , E ₄ at a selected frequency F and having an amplitude ranging from a first value to a second value less than the first value.

In fig. 4c shows the connection of the combined atomizer and conductivity sensor to the power supply in conductivity mode during the second half cycle, in which transistors T _4a and T _1c are conducting. The arrangement shown in FIG. 4c can be viewed as providing a second periodic voltage drop across the outer electrodes E ₁ , E ₄ with the same frequency and amplitude as the first periodic voltage drop, but with the opposite polarity and directly out of phase with the first periodic voltage.

The first and second periodic voltage drops have opposite polarities relative to each other, with opposite polarity in this context referring to the relative positions of the high and low voltage sides rather than the requirement of a positive voltage and a negative voltage. Since the drops of the first and second periodic voltages are applied from opposite external electrodes. Since the first and second periodic voltage drops are of opposite polarity and are directly out of phase, the AC voltage is effectively applied to the external electrodes. The first and second periodic voltage drops may have any suitable waveform. For example, two waveforms may be square waves that are directly out of phase with each other. Advantageously, the control electronics may be configured to provide a latency period of at least a few nanoseconds between the end of one voltage drop and the start of the next voltage drop in the opposite direction to avoid burning out the switches.

In the first half cycle, the second transistor T _4b of the second outer electrode E ₄ is conductive and provides a path to electrical ground through a resistor having a known resistance R ₂ . Microprocessor 220 is configured to sense the voltage V ₃ across resistor R ₂ and can determine the current flowing between the first external electrode E ₁ and the second external electrode E ₄ from the measured voltage V ₃ and the known resistance R ₂ .

In the second half cycle, the second transistor T _1b of the first external electrode E ₁ is conductive and provides a path to electrical ground through a resistor having a known resistance R ₁ . The control electronics are configured to measure the voltage V ₁ across the resistor R ₁ and can determine the current flowing between the second external electrode E ₄ and the first external electrode E ₁ from the measured voltage V ₁ and the known resistance R ₁ .

During the conductivity measurement mode, the control electronics are further adapted to apply a voltage to the gate of each of the second transistors T _1b , T _2b of the two internal electrodes E ₂ , E ₃ , so that the second transistors T _1b , T _2b of the two internal electrodes E ₂ , E ₃ are conductive. In conductivity mode, the control electronics do not apply voltage to the third transistors of any of the internal or external electrodes, so that all third transistors remain off.

Each of the second transistors T _2b , T _3b of the internal electrodes E ₂ , E ₃ provides a path to the input of a differential amplifier 322, the output of which is provided to the microprocessor 320 to provide the microprocessor 320 with a measurement of the voltage V ₂ at the internal electrodes E ₂ , E ₁ .

Microprocessor 320 may be configured in a variety of different ways to determine the nicotine concentration of the liquid aerosol substrate between the electrodes of the combined atomizer and conductivity sensor using the measured voltages V ₁ , V ₂ , and V ₃ . In this embodiment, the microprocessor 320 is adapted to determine the current between the outer electrodes E ₁ , E ₄ using the measured voltages V ₁ , V ₃ and to use the determined current and the measured voltage V ₂ at the inner electrodes E ₂ , E ₃ to determine the electrical conductivity of the liquid aerosol-forming substrate and determining the concentration of nicotine in the aerosol-forming liquid substrate.

In heating mode, the control electronics apply a high-frequency alternating switching voltage to the gate of each of the first transistors T _1a , T _2a , T _3a , T _4a of all electrodes E ₁ , E ₂ , E ₃ , E ₄ , so that all the first transistors periodically alternate between conducting and off states. The control electronics also apply voltage to the gate of each of the third transistors T _1c , T _2c , T _3c , T _4c of all electrodes E ₁ , E ₂ , E ₃ , E ₄ so that the third transistors are conductive. The third electrodes T _1c , T _2c , T _3c , T _4c provide a path to electrical ground.

In fig. 4d shows the connection of the combined atomizer and conductivity sensor 300 to the power supply in heating mode, with transistors T _1a , T _2a , T _3a , T _4a , T _1c , T _2c , T _3c , and T _4c conducting. The arrangement shown in FIG. 4d may be considered to include a third control circuit that operates to drive current through each of the electrodes.

By periodically switching the first transistors between conductive and off states and maintaining the third transistors conductive, the control electronics apply a pulsed direct current through each of the electrodes. The control electronics are configured to control the duty cycle of the pulses in order to control the temperature to which the electrodes are heated. Preferably, the control electronics are configured to control the duty cycle in the heating mode based on the nicotine concentration determined in the conductivity measurement mode.

It will be understood that in other embodiments, the control electronics of the aerosol generating device may not be adapted to directly supply power to the internal electrodes to heat the internal electrodes, but rather the control electronics may be adapted to heat the internal electrodes by induction. In these embodiments, an oscillating voltage is applied to the outer electrode, which induces a current in the inner electrodes. To ensure that the internal electrodes are heated to a sufficient temperature, it is preferable that the internal electrodes are susceptor-type elements made of magnetic material such as AISI 4xx stainless steel. Although the outer electrodes can be made of magnetic material, this is not an essential requirement in these embodiments.

In fig. 7 and 8 show schematic diagrams of another exemplary conductivity sensor 400. In this embodiment, the conductivity sensor 400 is not integrated with the atomizer. In this embodiment, the conductivity sensor is configured as a four-point conductivity sensor, which is located in the liquid storage portion of the cartridge of the aerosol generating device.

The cartridge includes a housing 401 defining a substantially cuboidal liquid storage portion. The housing is made of a rigid electrical insulating material such as PEEK. The conductivity sensor 400 includes four electrodes, two outer electrodes 404 and two inner electrodes 406. The first of the outer electrodes 404 and the first of the inner electrodes 406 are located on the first inner surface of the cartridge body 401, and the second of the outer electrodes 404 and the second of the inner electrodes 406 are located on a second inner surface of the cartridge body 401 opposite the first surface so that the first outer and inner electrodes face the second outer and inner electrodes on opposite sides of the liquid storage portion.

The outer electrodes 404 contain identical annular electrodes defining an outer electrode cavity 407. Inner electrodes 406 contains identical ring electrodes. As shown in FIG. 8, on the first inner surface of the cartridge body 401, the first outer electrode 404 and the first inner electrode 406 are arranged concentrically, with the first inner electrode 406 located in the outer electrode cavity 405 of the first outer electrode 404. Likewise, on the second inner surface of the cartridge body 401, the first outer electrode 404 and the first inner electrode 406 are arranged concentrically, with the second inner electrode 406 located in the outer electrode cavity 405 of the second outer electrode 404. The outer diameters of the inner electrodes 406 are smaller than the inner diameters of the outer electrodes 404, so that a space is provided between the inner and outer electrodes 404, 406. cavity. The cavity between the inner and outer electrodes 404, 406 electrically isolates the inner electrodes 406 from the outer electrodes 404 when no aerosol-forming liquid substrate is present in the cavity.

As shown in FIG. 7, the first inner and outer electrodes on the first inner side of the cartridge body 401 are aligned with the second inner and outer electrodes on the second inner side of the cartridge body 401. As such, the first and second outer electrodes 404 are substantially separated by the width of the liquid storage portion defining the cavity 408, and the first and second inner electrodes 406 are also substantially separated by the cavity 408 defined by the width of the liquid storage portion.

When the aerosol-forming liquid substrate is located in the liquid storage portion, the aerosol-forming liquid substrate can be located in the cavity 408 and contact the first and second electrodes 404, 406. In this embodiment, the aerosol-forming liquid substrate can move freely in the liquid storage section. However, in other embodiments, a carrier material may be provided in the liquid storage portion to hold the liquid aerosol-forming substrate. Such carrier material is typically a porous electrically insulating material that is located in the cavity 408 in contact with the inner and outer electrodes 404, 406.

As shown in FIG. 7, each of the external electrodes 404 is electrically coupled to the control electronics 410 of the aerosol generating device. Likewise, each of the internal electrodes 406 is electrically coupled 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.

The control electronics 410 is configured to apply an alternating voltage to the external electrodes 404, which can drive an alternating current through a liquid aerosol-forming substrate located in the cavity 408 between the first and second external electrodes 404. The control electronics are configured to sense a current between the first and second external electrodes 404.

The 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 sense a voltage across the first and second inner electrodes. The control electronics are further configured to use current and voltage measurements to determine the electrical conductivity of the liquid aerosol substrate located in cavity 408. The control electronics 410 may further determine the nicotine concentration of the liquid aerosol substrate based on the determined electrical conductivity.

It will 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 on a first side of the liquid storage portion and a second electrode on a second side of the liquid storage portion.

In this embodiment, the conductivity sensor 400 is located in the liquid storage portion of the cartridge; however, it will be understood that in other embodiments, the conductivity sensor 400 may be located in the liquid storage portion of the aerosol generating device or in a channel between the liquid storage portion and the nebulizer.

In fig. 9 and 10 show schematic diagrams of another exemplary conductivity sensor 500. In this embodiment, the conductivity sensor 500 is not integrated with the atomizer. In this embodiment, the conductivity sensor 500 is an inductive conductivity sensor that is located in the liquid storage portion of the cartridge of the aerosol generating device.

The conductivity sensor 500 contains two electrodes 504, 506 in the form of toroidal coils. The first of the coil electrodes is a field winding 504 wound around a first ring 505 of ferromagnetic material. The second of the coil electrodes is a receiving winding 506 wound around a second ring 507 of ferromagnetic material. Receiver winding 506 and ring 507 are substantially identical to field winding 504 and ring 505, including having the same number of turns and being wound in the same direction.

Each of the field winding 504 and the receiving winding 506 has an internal cavity through which the aerosol-forming substrate can flow. Receiver winding 506 is aligned with axial field winding 504 and spaced axially with field winding 504 such that the internal cavity of the receiving winding and the internal cavity of the field winding are aligned to substantially form a continuous cylindrical internal cavity through which a liquid substrate can flow to form aerosol. The field winding 504 is located and configured to induce a current in the receiving winding 506 when an alternating voltage is applied to the field winding 504.

Each end of the drive winding 504 and the receive winding 506 is electrically coupled to the control electronics 510 of the aerosol generating device.

The field winding 504 and ferromagnetic ring 505 and the receiving winding 506 and ferromagnetic ring 507 are embedded in an annular cylindrical housing 512 of an electrically insulating material, such as a plastic material, that is substantially impervious to the aerosol-forming liquid substrate. Accordingly, the housing 512 is in the form of a cylindrical tube having an internal cavity 514 that extends through the housing 512 and is open at both ends. The housing 512 is provided to protect the coil electrodes from the aerosol-forming liquid substrate. The housing 512 is configured to accommodate the liquid storage portion of the cartridge so that the aerosol-forming liquid substrate in the liquid storage portion is allowed to flow through the internal passage 514 and around the outer surfaces of the housing 501.

In use, the control electronics 510 is adapted to supply power to the field winding 504 in the form of an alternating voltage. The alternating voltage in the drive winding 504 creates a magnetic field that induces a current in the aerosol-forming liquid substrate located in the internal cavity 514. The current in the internal cavity 514 is indicated by arrow 516 in FIG. 7. The induced current 516 in the aerosol-forming liquid substrate also generates a magnetic field, which induces a current in the receiving winding 506. The electrical conductivity of the aerosol-forming liquid substrate affects the amount of current 516 induced in the aerosol-forming liquid substrate, which in turn influences the amount of current induced in the receiving winding 506. The control electronics 510 is configured to measure one or both of the voltage and current induced in the receiving winding, and is further configured to determine the electrical conductivity of the aerosol-forming liquid substrate based on one or more of measured induced current and voltage in the receiving winding. The control electronics can further determine the nicotine concentration in the aerosol-forming liquid substrate based on the determined electrical conductivity.

Claims (40)

1. A system for generating an aerosol, containing: a liquid storage portion for holding a liquid substrate forming an aerosol; a sprayer in fluid communication with the liquid storage portion; a conductivity sensor arranged to measure the electrical conductivity of the aerosol-forming liquid substrate from the liquid storage portion, the conductivity sensor comprising at least two electrodes; power unit; And control electronics configured to: controlling the supply of power from the power supply to the atomizer for spraying a liquid substrate forming an aerosol from the liquid storage portion; controlling the supply of power from the power supply to the electrodes of the conductivity sensor, while power is supplied to the conductivity sensor in the form of alternating voltage; receiving one or more measurements indicating the conductivity of the aerosol-forming liquid substrate from the conductivity sensor; And determining the concentration of nicotine in the aerosol-forming liquid substrate based on one or more measurements from the conductivity sensor. 2. The aerosol generating system according to claim 1, wherein the control electronics are further configured to control the supply of power from the power supply to the atomizer for atomizing the liquid aerosol-forming substrate based on a certain concentration of nicotine in the liquid aerosol-forming substrate. 3. The aerosol generating system according to claim 2, wherein the control electronics are configured to control the supply of power from the power supply to the atomizer for atomizing the aerosol-forming liquid substrate based on a certain concentration of nicotine in the aerosol-forming liquid substrate by comparison a certain concentration of nicotine with a predetermined threshold value, applying a first power to the atomizer when the determined nicotine concentration is equal to or lower than the predetermined threshold value, and applying a second power to the atomizer that is less than the first power when the determined nicotine concentration is greater than the predetermined threshold value. 4. System for generating an aerosol according to any one of paragraphs. 1-3, characterized in that it further comprises a heater arranged to heat the aerosol-forming substrate from the liquid storage portion, and wherein the control electronics is configured to supply power from the power supply to the heater for heating the liquid aerosol-forming substrate, from the liquid storage part to a predetermined temperature. 5. System for generating an aerosol according to any one of paragraphs. 1-4, characterized in that it further comprises a temperature sensor positioned to measure the temperature of the aerosol-forming liquid substrate from the liquid storage portion; And The control electronics are additionally designed to: receiving one or more temperature measurements of the aerosol-forming liquid substrate at the conductivity sensor from the temperature sensor; And adjusting the determination of nicotine concentration based on one or more temperature measurements. 6. System for generating an aerosol according to any one of paragraphs. 1-5, characterized in that each electrode of the conductivity sensor is arranged to come into contact with an aerosol-forming liquid substrate from the liquid storage portion. 7. The aerosol generating system according to claim 6, wherein the conductivity sensor comprises two electrodes, and wherein said two electrodes are spaced apart to form a cavity in which an aerosol-generating liquid substrate is located from the liquid storage portion. 8. The aerosol generating system according to claim 7, wherein the atomizer is a thermal atomizer comprising a plurality of heating elements, and wherein each of the conductivity sensor electrodes is formed from a heating element of the atomizer. 9. System for generating an aerosol according to claim 8, characterized in that the control electronics are additionally configured to: applying first power to electrodes of the conductivity sensor to measure the electrical conductivity of the liquid substrate forming the aerosol; And supplying a second power to a plurality of heating elements of the atomizer to atomize the liquid substrate to form an aerosol, the second power being greater than the first power. 10. System for generating an aerosol according to claim 6, characterized in that: the conductivity sensor contains two internal electrodes and two external electrodes; two outer electrodes are spaced apart from each other to form an outer cavity in which an aerosol-forming liquid substrate from the liquid storage portion is disposed; two inner electrodes are located in an outer cavity between the two outer electrodes and spaced apart from each other to form an inner cavity in which an aerosol-forming liquid substrate from the liquid storage portion is located; And The control electronics are additionally designed to: supplying power from the power supply to the external electrodes, while power is supplied to the external electrodes in the form of alternating voltage; And receiving one or more measurements indicating the conductivity of the aerosol-forming liquid substrate from the internal electrodes. 11. The aerosol generating system of claim 10, wherein the atomizer is a thermal atomizer comprising a plurality of heating elements, and wherein each of the conductivity sensor electrodes is formed from a heating element of the atomizer. 12. System for generating an aerosol according to claim 11, characterized in that the control electronics are additionally configured to: applying first power to external electrodes of the conductivity sensor to measure the conductivity of the liquid substrate forming the aerosol; And supplying a second power to a plurality of heating elements of the atomizer to atomize the liquid substrate to form an aerosol, the second power being greater than the first power. 13. System for generating an aerosol according to any one of paragraphs. 1-5, characterized in that the conductivity sensor includes two electrodes, a first electrode and a second electrode, wherein each electrode forms a coil, wherein the control electronics are configured to apply an alternating voltage to the first electrode and the control electronics are configured to receive one or more measurements indicating the conductivity of the aerosol-forming liquid substrate from the second electrode, and wherein the first electrode is positioned to induce a current in the second electrode when an alternating voltage is applied to the first electrode. 14. The aerosol generating system according to claim 13, characterized in that the first electrode and the second electrode are located in the liquid storage portion. 15. A cartridge for a system for generating an aerosol, the cartridge containing: a liquid storage portion for holding a liquid substrate forming an aerosol; a sprayer in fluid communication with the liquid storage portion; And a conductivity sensor disposed to measure the electrical conductivity of the aerosol-forming liquid substrate from the liquid storage portion, wherein the conductivity sensor comprises two electrodes, a first electrode and a second electrode, disposed in the liquid storage portion, each electrode defining a coil, wherein the first electrode arranged to induce a current in the second electrode when an alternating voltage is applied to the first electrode.