Cartridge with Thermochromatic Thermally Conductive Elements - Patent application

Abstract

A replaceable cartridge is provided. The replaceable cartridge comprises a liquid storage portion including a liquid aerosol-forming substrate. The replaceable cartridge comprises a vaporizer configured to vaporize the liquid aerosol-forming substrate. The replaceable cartridge comprises a thermochromatic thermally conductive element in thermal contact with the vaporizer, the thermochromatic thermally conductive element having a temperature threshold above which it undergoes a color change.

Description

[Technical field]

[0001] The present invention relates to a cartridge in which an aerosol is generated by vaporizing a liquid aerosol-forming substrate using a vaporizer, and to an aerosol-generating system comprising such a cartridge. [Background technology]

[0002] One type of aerosol generating system is one that operates by heating a liquid aerosol-forming substrate to generate a vapor. Such liquid is usually called e-liquid. The vapor then cools and forms an aerosol. Most systems of this type use some form of liquid-holding material, such as a wick, to hold the liquid aerosol-forming substrate and typically deliver it to the heating element. However, as the amount of liquid aerosol-forming substrate decreases and the liquid-holding material dries, less liquid is delivered to the heating element, which may result in less aerosol being delivered and may lead to the heating element being overheated. Also, as the liquid-holding material dries, it becomes more susceptible to charring or burning. This can result in undesirable compounds in the generated aerosol. This can also result in a burnt odor or unpleasant flavor. Similarly, users may refill an empty cartridge with an unknown e-liquid, which can lead to contaminating the cartridge by using an incompatible e-liquid.

[0003] Cartridges and aerosol generating systems are known that provide protection against overheating and refilling with incompatible e-liquids. However, this type of protection can lead to increased costs for the cartridges and systems. It would be desirable to provide a cartridge and aerosol generating system that can overcome at least some of the above drawbacks in an efficient and inexpensive manner. Summary of the Invention

[0004] A replaceable cartridge may be provided. The replaceable cartridge may comprise a liquid storage portion including a liquid aerosol-forming substrate. The replaceable cartridge may comprise a vaporizer configured to vaporize the liquid aerosol-forming substrate. The vaporizer may comprise a wick configured to absorb the liquid aerosol-forming substrate. The replaceable cartridge may comprise a thermochromatic thermally conductive element in thermal contact with the vaporizer, the thermochromatic thermally conductive element having a temperature threshold above which it undergoes a color change. The replaceable cartridge may comprise a cartridge air inlet. The replaceable cartridge may comprise a cartridge air outlet, the cartridge air inlet and the cartridge air outlet being arranged to define an airflow path between the cartridge air inlet and the cartridge air outlet, the cartridge air outlet being configured to allow the vaporized liquid aerosol-forming substrate to exit.

[0005] A replaceable cartridge may be provided, the replaceable cartridge comprising: a liquid storage portion comprising a liquid aerosol-forming substrate; a vaporizer configured to vaporize a liquid aerosol-forming substrate, the vaporizer comprising a wick configured to absorb the liquid aerosol-forming substrate; a thermochromatic heat conductive element in thermal contact with the vaporizer, the thermochromatic heat conductive element having a temperature threshold above which it undergoes a color change; -Cartridge air intake, - a cartridge air outlet, the cartridge air inlet and the cartridge air outlet being arranged to define an airflow path between the cartridge air inlet and the cartridge air outlet, the cartridge air outlet being configured to allow the exit of vaporized liquid aerosol-forming substrate.

[0006] As used herein, the term "replaceable cartridge" refers to a cartridge that may not be refillable. Therefore, when the liquid in the liquid storage portion is depleted, the cartridge must be discarded. The cartridge can then be replaced with a new cartridge in the aerosol generation system.

[0007] Because the cartridge is replaceable, the risk of refilling the liquid reservoir with poor quality liquid aerosol-forming substrate is minimized.

[0008] The term "aerosol-forming substrate" as used herein relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate.

[0009] The liquid aerosol-forming substrate preferably has suitable physical properties (e.g. boiling point and vapor pressure) for use in the cartridge: if the boiling point is too high, the liquid may not heat, but if the boiling point is too low, the liquid may heat too easily.

[0010] The liquid aerosol-forming substrate may comprise nicotine. The nicotine-containing liquid aerosol-forming substrate may be a nicotine salt matrix. The liquid aerosol-forming substrate may comprise plant-derived material. The liquid aerosol-forming substrate may comprise tobacco. The liquid aerosol-forming substrate may comprise homogenized tobacco material. The liquid aerosol-forming substrate may comprise a non-tobacco containing material. The liquid aerosol-forming substrate may comprise homogenized plant-derived material.

[0011] The liquid aerosol-forming substrate may include at least one aerosol former. The aerosol former is any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol upon use. Suitable aerosol formers are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). The aerosol former may be a polyhydric alcohol or a mixture thereof (such as triethylene glycol, 1,3-butanediol, glycerin, etc.).

[0012] The liquid aerosol-forming substrate may contain other additives and ingredients, such as flavorants.

[0013] The liquid aerosol-forming substrate may comprise water.

[0014] The liquid aerosol-forming substrate may include nicotine and at least one aerosol former. The aerosol former may include glycerin. The aerosol former may include propylene glycol. The aerosol former may include both glycerin and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration of about 0.1 percent to about 10 percent.

[0015] The cartridge may comprise a liquid storage section for storing the liquid aerosol-forming substrate. The advantage of providing a liquid storage section is that the liquid in the liquid storage section is protected from ambient air, or light, or both air and light (as air generally cannot enter the liquid storage section), so that the risk of deterioration of the liquid is significantly reduced. Furthermore, a high level of hygiene can be maintained.

[0016] The liquid reservoir may have a capacity of about 1 mL to 5 mL.

[0017] The vaporizer of the replaceable cartridge may include a wick for absorbing the liquid aerosol-forming substrate.

[0018] The wick may be disposed in contact with the liquid aerosol-forming substrate in the liquid storage portion. The wick may extend into the liquid storage portion. The liquid aerosol-forming substrate may have physical properties, including surface tension and viscosity, that allow the liquid to be moved through the wick by capillary action or by any other physical law.

[0019] The wick may be a capillary wick designed to transport the liquid aerosol-forming substrate by capillary action. When the wick is a capillary wick, it may have a fibrous or spongy structure. The capillary wick may comprise a bundle of capillaries. The capillary wick may comprise a plurality of fibers or threads, or other fine tubes. The capillary wick may comprise a sponge-like or foam-like material formed into a rod shape. The structure of the capillary wick may form a plurality of small holes or tubes through which liquid can be transferred by capillary action. The capillary wick may comprise any suitable material or combination of materials. Suitable materials may be capillary materials such as sponge or foam materials, ceramic- or graphite-based materials in the form of fibers or sintered powders, foamed metal or plastic materials, fibrous materials made of, for example, spun or extruded fibers (such as cellulose acetate, polyester, or bonded polyolefin, polyethylene, terylene or polypropylene fibers, nylon fibers or ceramics). The capillary wick may have any suitable capillarity and porosity to be used with liquid aerosol-forming substrates having different physical properties. The liquid aerosol-forming substrate may have physical properties including, but not limited to, viscosity, surface tension, density, thermal conductivity, boiling point and vapor pressure that allow the liquid aerosol-forming substrate to be moved through the capillary device by capillary action. The capillary wick must be suitable to absorb the amount of liquid required.

[0020] The wick may comprise a porous interface different from the capillary material for absorbing and transporting a desired amount of the liquid aerosol-forming substrate.

[0021] The liquid aerosol-forming substrate may be adsorbed, coated, impregnated or otherwise loaded onto any suitable carrier or support.

[0022] The wick may comprise a porous ceramic.The wick may comprise a solid open-cell porous ceramic.The porous ceramic allows the liquid aerosol-forming substrate to flow into the wick.

[0023] The vaporizer may include at least one heating element capable of heating the liquid aerosol-forming substrate by one or more of conduction, convection, and radiation.

[0024] The at least one heating element may be powered by a non-electrical power source, such as a combustible fuel. The at least one heating element may comprise a thermally conductive element, also known as a thermally conductive element, that is heated by combustion of a gaseous fuel. The at least one heating element may heat the aerosol-forming substrate by conduction and may be in at least partial thermal contact with a wick in which the substrate is imbibed.

[0025] The terms "thermally conductive" and "thermally conductive" as used herein refer to a material having a thermal conductivity of at least 10 W / mK, preferably at least 40 W / mK, and more preferably at least 100 W / mK at 23 degrees Celsius and 50% relative humidity. Preferably, a thermally conductive material has a material having a thermal conductivity of at least 40 W / mK, preferably at least 100 W / mK, more preferably at least 150 W / mK, and even more preferably at least 200 W / mK at 23 degrees Celsius and 50% relative humidity.

[0026] Heat from the at least one heating element may be conducted to a wick, which may heat the liquid aerosol-forming substrate. Heat from the at least one heating element may be conducted to the wick by an intermediate thermally conductive element. Heat from the at least one heating element may be conducted directly to the wick without any intermediate thermally conductive element.

[0027] The replaceable cartridge may be electrically operated and the vaporizer may include an electrical heating element for heating the aerosol-forming substrate. The electrical heating element may be powered by an electrical power supply.

[0028] The electric heating element may comprise a single heating element. The electric heating element may comprise two or more heating elements, for example two, or three, or four, or five, or six or more heating elements. The heating element or elements may be suitably arranged to most effectively heat the liquid aerosol-forming substrate.

[0029] When the at least one heating element comprises an electric heating element, the electric heating element may comprise an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, metal alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. Suitable doped ceramics may include doped silicon carbide. Suitable metals may include titanium, zirconium, tantalum, and platinum group metals. Suitable metal alloys may include stainless steel, constantan, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, iron-containing alloys, nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, iron-aluminum-based alloys, and iron-manganese-aluminum-based alloys. Timetal® is a registered trademark of Titanium Metals Corporation, 1999 Broadway Suite 4300, Denver Colorado. In composite materials, the electrically resistive material may be embedded in, encapsulated in, or coated with an insulating material, or vice versa, depending on the required energy transfer kinetics and external physicochemical properties. The heating element may include a metallic etched foil insulated between two layers of inert material. In that case, the inert material may include Kapton®, full-layer polyimide, or mica foil. Kapton® is a registered trademark of EI du Pont de Nemours and Company, 1007 Market Street, Wilmington, Delaware 19898, United States of America.

[0030] When the at least one heating element comprises an electric heating element, the electric heating element may comprise an infrared heating element, a photon source, or an induction heating element.

[0031] The electric heating element may be a disk heating element. The electric heating element may comprise a flexible sheet of material. The electric heating element may comprise a heating wire or filament (e.g., nickel-chromium (Ni-Cr), platinum, tungsten or alloy wire or heating plate). The electric heating element may be disposed in or on a rigid carrier material.

[0032] The electric heating element may comprise a heat sink or heat reservoir, which comprises a material capable of absorbing and storing heat, and then releasing heat over time to heat the liquid aerosol-forming substrate. The heat sink may be formed of any suitable material, such as a suitable metal or ceramic material. The material may have a high heat capacity (sensible heat storage material) or may be a material capable of absorbing heat and then releasing heat via a reversible process (such as a high temperature phase change). Suitable sensible heat storage materials include, but are not limited to, silica gel, alumina, carbon, glass mat, glass fiber, ceramic minerals, metals or alloys (such as aluminum, silver, or lead), and cellulosic materials. Other suitable materials that release heat by a reversible phase change include, but are not limited to, paraffin, sodium acetate, naphthalene, wax, polyethylene oxide, metals, metal salts, mixtures of eutectic salts, or alloys.

[0033] The heat sink may be in direct contact with the liquid aerosol-forming substrate and arranged so as to be able to transfer the stored heat directly to the substrate. The heat stored in the heat sink or heat store may also be transferred to the liquid aerosol-forming substrate by means of a thermal conductor such as a metal tube.

[0034] The wick may include a thermally conductive material, which may enable the wick to receive heat to vaporize the liquid aerosol-forming substrate absorbed by the wick. The heat may be received from a heating element in thermal contact with the wick.

[0035] The wick may be the heating element. When the wick is the heating element, it may be the only heating element of the vaporizer. Similarly, when the wick is the heating element, the vaporizer may include one or more heating elements in addition to the wick. When the wick is the heating element, it may include an electrically conductive material that can be heated when supplied with electrical current from a power source. The electrically conductive material may be a porous ceramic.

[0036] As used herein, "electrically conductive" refers to a material that has an electrical resistivity of less than or equal to 1×10-4 ohm-meter (Ω·m) at 20 degrees Celsius.

[0037] The wick may be arranged to act as a heat sink.

[0038] In use, the liquid aerosol-forming substrate may be transferred from the liquid storage portion into the wick and vaporized by the vaporizer to form a supersaturated vapor. The supersaturated vapor is mixed with air entering the replaceable cartridge through the cartridge air inlet and carried in the airflow path. During the flow, the vapor condenses to form an aerosol, which is carried through the cartridge air outlet toward the user's mouth.

[0039] The replaceable cartridge may include a thermochromatic thermally conductive element in thermal contact with the vaporizer, the thermochromatic thermally conductive element having a temperature threshold above which it undergoes a color change.

[0040] The thermochromatic heat conductive element may be in thermal contact with the core. The thermochromatic heat conductive element may be in thermal contact with at least one heating element.

[0041] Since the thermochromatic heat-conductive element has a temperature threshold above which it undergoes a color change and is in thermal contact with the vaporizer, the temperature threshold can be selected to correspond to the temperature above which the vaporizer overheats, for example due to an insufficient amount of liquid aerosol-forming substrate in the liquid storage portion. Thus, the color change may indicate that the vaporizer is overheating. As a result, the thermochromatic heat-conductive element may provide a reliable and inexpensive solution to prevent overheating of the vaporizer and an insufficient amount of liquid aerosol-forming substrate in the liquid storage portion. Since overheating of the vaporizer and an insufficient amount of liquid aerosol-forming substrate may result in undesirable compounds, odors, flavors, or combinations thereof in the generated aerosol and may result in aerosols with undesirable particle sizes, the provision of a thermochromatic heat-conductive element may be beneficial to improve the user's experience.

[0042] The color change may be irreversible, which is beneficial in ensuring that the indication that the vaporizer is overheating is not overturned by refilling a replaceable cartridge, thus reducing the risk of using an incompatible aerosol-forming substrate in the cartridge.

[0043] The liquid reservoir may be annular and may define an interior passageway surrounded by the liquid reservoir.

[0044] An annular liquid storage portion defining the inner passage may allow for a more compact and replaceable cartridge, as the inner passage is for the flow of vaporized liquid aerosol-forming substrate, while the surrounding liquid storage portion contains the pre-vaporized liquid aerosol-forming substrate.

[0045] The cartridge air outlet may be located at a downstream end of the inner passage.

[0046] The replaceable cartridge may comprise a mouthpiece. The mouthpiece may comprise a cartridge air outlet. The replaceable cartridge may comprise any suitable number of cartridge air outlets. The replaceable cartridge may comprise multiple cartridge air outlets.

[0047] The replaceable cartridge may include any suitable number of cartridge air inlets. The replaceable cartridge may include multiple cartridge air inlets.

[0048] The vaporizer may be located at the upstream end of the inner passageway, this arrangement being beneficial in facilitating absorption of the liquid aerosol-forming substrate in the wick and entrainment of the vaporized liquid aerosol-forming substrate in the airflow along the inner passageway.

[0049] As used herein, the terms "upstream," "front," "downstream," and "rear" are used to describe the relative location of components or portions of components of the replaceable cartridge and aerosol generation system with respect to the direction in which a user draws on the replaceable cartridge or aerosol generation system during use. Similarly, these terms are also used to describe the relative location of components or portions of components of the aerosol generation device with respect to the orientation of the aerosol generation device when assembled into the aerosol generation system.

[0050] The replaceable cartridge and aerosol generating system have a downstream end through which the aerosol exits the cartridge and system for delivery to a user in use. The aerosol generating device has a downstream end, which is the end configured to be closest to the downstream end of the aerosol generating system when the aerosol generating device is assembled into the aerosol generating system. The proximal end of the replaceable cartridge, aerosol generating system, aerosol generating device may also be referred to as the oral end. In use, a user breathes on the oral end of the replaceable cartridge and aerosol generating system. The oral end is downstream of and opposite the distal end. The distal end is also known as the upstream end. Components or portions of components of the replaceable cartridge, aerosol generating system, aerosol generating device may be described as being upstream or downstream of each other based on their relative location between the proximal and distal ends of the cartridge, aerosol generating system, aerosol generating device. The distal end of a component or portion of a component of the cartridge, aerosol generating system, aerosol generating device is the portion of the cartridge, aerosol generating system, aerosol generating device that is closest to the upstream end of the cartridge, aerosol generating system, aerosol generating device. The proximal end of a cartridge, aerosol generation system, component or portion of a component is the portion that is closest to the downstream end of the cartridge, aerosol generation system, aerosol generation device.

[0051] The term "longitudinal" as used herein refers to a direction corresponding to a major longitudinal axis of a replaceable cartridge, aerosol generation system, or aerosol generation device extending between the upstream and downstream ends of the replaceable cartridge, aerosol generation system, or aerosol generation device.

[0052] In use, air is drawn longitudinally through the replaceable cartridge, aerosol generation system, or aerosol generator. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross section" of the replaceable cartridge, aerosol generation system, or aerosol generator, or a component of the replaceable cartridge, aerosol generation system, or aerosol generator, refers to a transverse section, unless otherwise specified.

[0053] The term "length" refers to the dimension of a replaceable cartridge, aerosol generation system, or component of an aerosol generation device along its longitudinal axis.

[0054] The replaceable cartridge may have a length of about 1.5 cm to 2.75 cm. The replaceable cartridge may have a diameter of about 0.3 cm to 0.7 cm.

[0055] The thermochromatic thermally conductive element is a separate element from the liquid aerosol-forming substrate and is not suspended or dissolved in the liquid aerosol-forming substrate. The thermochromatic thermally conductive element may comprise a body. The body may comprise a porous ceramic. The thermochromatic thermally conductive element may comprise a layer of thermochromatic material on the body. The thermochromatic thermally conductive element may comprise a layer of thermochromatic material printed on the body. The layer of thermochromatic material may comprise an inorganic material or a leuco dye. The layer of thermochromatic material may comprise chromium (III) oxide.

[0056] The thermochromatic thermally conductive element may comprise a porous layer. The porous layer may include a temperature sensitive material, such as a PTC thermistor or an NTC thermistor.

[0057] PTC and NTC thermistors are heat-sensitive resistors that can be heated when an electric current is applied to them. When a PTC or NTC thermistor is heated, the temperature and resistance of the PTC or NTC thermistor can change according to functions related to both parameters.

[0058] In a PTC thermistor, there is a stabilization temperature range within which the resistance of the PTC thermistor increases as the temperature of the PTC thermistor increases within the stabilization temperature range. Similarly, in an NTC thermistor, there is a stabilization temperature range within which the resistance of the NTC thermistor decreases as the temperature of at least one PTC thermistor increases within the stabilization temperature range.

[0059] Within the stabilization temperature range, the increase or decrease in the resistance of a PTC or NTC thermistor as its temperature increases is typically rapid enough to allow for very slow fluctuations in the temperature of the PTC or NTC thermistor. As used herein, "stabilization temperature range" should be interpreted as the range of temperature of a PTC or NTC thermistor over which the temperature is not necessarily constant, even though the change in temperature of the PTC or NTC thermistor may be negligible relative to the change in resistance of the PTC or NTC thermistor.

[0060] Thus, the at least one PTC thermistor may stabilize at substantially a reference temperature (or a temperature slightly above or below the reference temperature) within the stabilization temperature range for a period of time that may be longer than the normal operating period of the replaceable cartridge of the present disclosure.

[0061] A thermochromatic heat conductive element comprising a porous layer with a temperature sensitive material (such as a PTC thermistor or an NTC thermistor) may be less susceptible to overheating, since the temperature of the temperature sensitive material may not significantly exceed the reference temperature. The reference temperature of the thermochromatic heat conductive element may be selected to be similar to, and preferably slightly higher than, the temperature threshold of the thermochromatic heat conductive element. This may avoid overheating of the thermochromatic heat conductive element when the vaporizer overheats.

[0062] The wick may have a peripheral wall extending along a longitudinal axis of the replaceable cartridge. The thermochromatic thermally conductive element may be disposed at least partially about the peripheral wall of the wick.

[0063] By disposing the thermochromatic thermally conductive element at least partially around a peripheral wall of the core, thermal contact between the thermochromatic thermally conductive element and the core may be facilitated.

[0064] The thermochromatic thermally conductive element may include an absorbent material, which may allow the liquid aerosol-forming substrate to flow from the liquid storage portion to the wick through the thermochromatic thermally conductive element, even when the thermochromatic thermally conductive element is at least partially disposed around a peripheral wall of the wick.

[0065] The replaceable cartridge may include a housing. The housing may include a transparent portion that allows the thermochromatic thermally conductive element to be visible from an exterior of the replaceable cartridge.

[0066] The transparent portion may allow a user to perceive a color change in the thermochromatic thermal conductivity and therefore interpret the vaporizer as overheating.

[0067] The transparent portion may correspond to a section of the housing. The transparent portion may correspond to the entire housing.

[0068] An aerosol generation system may also be provided that may comprise any of the replaceable cartridges described above and a reusable aerosol generation device that may comprise a power source configured to provide power to the vaporizer.

[0069] As used herein, the term "aerosol generating device" refers to a device that includes a power source configured to interact with an aerosol-forming substrate of a cartridge to generate an aerosol. A "reusable aerosol generating device" refers to an aerosol generating device that is configured to form an aerosol generating system with a replaceable cartridge such that when the replaceable cartridge is depleted and discarded, the reusable aerosol generating device can be combined with a new replaceable cartridge.

[0070] As used herein, the term "aerosol generating system" refers to the combination of an aerosol generating device and a cartridge that contains an aerosol-forming substrate.

[0071] Because the aerosol generation system comprises the replaceable cartridge described above, the advantages identified above for the replaceable cartridge also apply to the system itself.

[0072] The aerosol generating device may comprise a control unit.

[0073] The control unit may be any suitable control unit. The control unit may comprise any suitable electrical circuitry and electrical components. The control unit may comprise a processor and a memory.

[0074] The control unit may be configured to control the supply of power (eg, current) from the power source to the vaporizer of the replaceable cartridge.

[0075] The control unit may comprise an electrical circuit connected to the power source and the vaporizer. The electrical circuit may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontrol unit, an application specific integrated circuit chip (ASIC), or other electronic circuit capable of providing control. The electrical circuit may comprise further electronic components. The control unit may be configured to continuously provide power to the vaporizer after activation of the aerosol generating device. The control unit may be configured to intermittently provide power to the vaporizer. The control unit may be configured to provide power to the vaporizer on a puff-by-puff basis.

[0076] The control unit may be configured to determine or estimate a temperature of the vaporizer, or the thermochromatic thermally conductive element, or both the vaporizer and the thermochromatic thermally conductive element, and to discontinue supply of power from the power source to the vaporizer when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0077] Determining or estimating the temperature of the vaporizer, or the thermochromatic heat conductive element, or both the vaporizer and the thermochromatic heat conductive element, and cutting off the power supply when the determined or estimated temperature exceeds a predefined threshold stored in the control unit, may be beneficial to ensure that the aerosol generating system does not operate when the vaporizer overheats. This may reduce the risk of using the aerosol generating system when the vaporizer overheats, for example due to an insufficient supply of liquid aerosol-forming substrate to the wick. This may reduce the risk of inhaling undesirable compounds, or aerosols with undesirable odors, flavors or particle sizes, or combinations thereof, thus improving the user's experience.

[0078] The temperature of the vaporizer, or the thermochromatic thermally conductive element, or both the vaporizer and the thermochromatic thermally conductive element, may be determined or estimated as a function of the electrical conductivity of the components of the vaporizer, or the thermochromatic thermally conductive element, or both the vaporizer and the thermochromatic thermally conductive element, relying on known relationships between electrical conductivity and temperature of certain materials. This may provide an accurate and inexpensive method of determining or estimating the temperature of the vaporizer, or the thermochromatic thermally conductive element, or both the vaporizer and the thermochromatic thermally conductive element.

[0079] The component of the thermochromatic thermally conductive element whose conductivity is measured may be the porous layer.The component of the vaporizer whose conductivity is measured may be the heating element.

[0080] The vaporizer, or the thermochromatic thermally conductive element, or both the vaporizer and the thermochromatic thermally conductive element components whose conductivity is measured may form a feedback loop with the control unit, which may facilitate measurement of the conductivity of the components and, as a result, a determination or estimation of the temperature of the components.

[0081] The aerosol generating device may be equipped with a display or an audible alarm, and the control unit may be configured to modify a warning signal issued by the display or the audible alarm when the determined or estimated temperature exceeds a predefined threshold stored in the control unit.

[0082] A change in the warning signal may be advantageous to provide an indication to the user that the replaceable cartridge needs to be replaced. The warning signal may be used in addition to providing a thermochromatic thermally conductive element, thus providing a dual indication as to the suitability of the replaceable cartridge.

[0083] The predetermined temperature threshold stored in the control unit may be substantially the same as the temperature threshold of the thermochromatic thermally conductive element, which may provide a consistent dual indication of the suitability of the replaceable cartridge.

[0084] The temperature threshold of the thermochromatic thermally conductive element may be between about 240 degrees Celsius and 250 degrees Celsius, preferably 245 degrees Celsius.

[0085] The predetermined temperature threshold stored in the control unit may be between about 240 degrees Celsius and 250 degrees Celsius, preferably 245 degrees Celsius.

[0086] The electrical circuitry may be operable to permanently disable the replaceable cartridge when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0087] Permanently disabling a replaceable cartridge may provide greater user safety: by permanently disabling a replaceable cartridge, the cartridge cannot be refilled and reused, although there may be a risk that the cartridge could be refilled with an inferior, and possibly incompatible, substance.

[0088] The power source may be any suitable type of power source. The power source may be a DC power source. The power source may be a battery, such as a rechargeable lithium ion battery. The power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. The power source may have a capacity that allows for the storage of sufficient energy for one or more uses of the device. For example, the power source may have a capacity sufficient to allow for continuous generation of aerosol for about 6 minutes, or a multiple of 6 minutes, corresponding to the typical time it takes to smoke one conventional cigarette. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of uses of the device, or for discontinuous activation. The power source is a DC power source having a DC supply voltage in the range of about 2.5 volts to about 4.5 volts and a DC supply current in the range of about 1 amp to about 10 amps (corresponding to a DC power source in the range of about 2.5 watts to about 45 watts).

[0089] The aerosol generating device may advantageously comprise a DC / AC inverter, which may comprise a class C, class D or class E power amplifier.

[0090] The aerosol generating device may further include a DC / DC converter between the power supply and the DC / AC converter.

[0091] The aerosol generating device may include a device housing. The device housing may be elongated. As used herein, the term "elongated" means that an element has a length dimension that is greater than its width dimension or its diameter dimension, for example, a length dimension that is more than twice its width dimension or its diameter dimension.

[0092] The device housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composites containing one or more of these materials, or thermoplastics suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), polyethylene. The material may be lightweight and not brittle.

[0093] The device housing may include a device air inlet. The device air inlet may be configured to allow ambient air to enter the device housing. The device may include any suitable number of device air inlets. The device may include multiple device air inlets.

[0094] The device housing may include a device air outlet. The device air outlet may be configured to allow air to exit the device housing for delivery to the air inlet of the replaceable cartridge. The device may include any suitable number of device air outlets. The device may include multiple device air outlets.

[0095] The device air inlet may comprise the air inlet of the aerosol generation system.The cartridge air outlet may comprise the air outlet of the aerosol generation system.

[0096] The aerosol generating device may include an airflow sensor for detecting airflow indicative of a user taking a puff. The airflow sensor may be an electromechanical device. The airflow sensor may be any of a mechanical device, an optical device, an opto-mechanical device, and a microelectromechanical system (MEMS) based sensor. The aerosol generating device may include a manually operable switch for a user to initiate a puff.

[0097] The aerosol generating device may comprise an indicator for indicating when the at least one heating element is activated. The indicator may comprise a light that is activated when the at least one heating element is activated.

[0098] The aerosol generating device may include at least one electrical connector. The at least one electrical connector may be configured to charge the power source. The at least one electrical connector may be configured to be connected to another electrical device. The at least one electrical connector may include an outer plug or socket with at least one outer electrical contact that allows the aerosol generating device to be connected to another electrical device. For example, the aerosol generating device may include a USB plug or socket that allows the aerosol generating device to be connected to another USB-enabled device. For example, the USB plug or socket may allow the aerosol generating device to be connected to a USB charging device to charge a rechargeable power source within the aerosol generating device. The USB plug or socket may support data transfer to the aerosol generating device, data transfer from the aerosol generating device, or both data transfer to and from the aerosol generating device. Similarly, the aerosol generating device may be connected to a computer to transfer data, such as a new heating profile, to the device.

[0099] When the aerosol generating device comprises a USB plug or USB socket, the aerosol generating device may further comprise a removable cover for covering the USB plug or USB socket when not in use. When the USB plug or USB socket is a USB plug, the USB plug may be selectively retractable within the device.

[0100] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or disclosure described herein. EXAMPLES

[0101] Example 1 A replaceable cartridge, comprising: a liquid storage portion comprising a liquid aerosol-forming substrate; a vaporizer configured to vaporize a liquid aerosol-forming substrate; a thermochromatic heat conductive element in thermal contact with the vaporizer, the thermochromatic heat conductive element having a temperature threshold above which it undergoes a color change; -Cartridge air intake, and a cartridge air outlet, the cartridge air inlet and the cartridge air outlet being arranged to define an airflow path between the cartridge air inlet and the cartridge air outlet, the cartridge air outlet being configured to allow vaporized liquid aerosol-forming substrate to exit.

[0102] Example 2 The replaceable cartridge of example 1, wherein the vaporizer comprises a wick.

[0103] Example 3 The replaceable cartridge of example 2, wherein the wick comprises a capillary material.

[0104] Example 4 A replaceable cartridge according to any one of Examples 2-3, wherein the wick comprises a porous interface.

[0105] Example 5 The replaceable cartridge of any one of Examples 2-4, wherein the wick comprises a thermally conductive material.

[0106] Example 6 The replaceable cartridge of any one of Examples 2-5, wherein the wick comprises a porous ceramic.

[0107] Example 7. The replaceable cartridge of any one of Examples 6, wherein the porous ceramic is a solid open-cell porous ceramic.

[0108] Example 8. A replaceable cartridge according to any one of Examples 1 to 7, wherein the liquid storage portion is annular and defines an inner passage surrounded by the liquid storage portion, the airflow path comprises the inner passage, and the cartridge air outlet is disposed at a downstream end of the inner passage.

[0109] Example 9. The replaceable cartridge of example 8, wherein the vaporizer is disposed at the upstream end of the inner passage.

[0110] Example 10. The replaceable cartridge of any one of Examples 1 to 9, wherein the vaporizer comprises at least one heating element.

[0111] Example 11 The replaceable cartridge of example 10, wherein the at least one heating element comprises an electric heating element.

[0112] Example 12 The replaceable cartridge of example 11, wherein the electrical heating element is a resistive heating element.

[0113] Example 13 The replaceable cartridge of any one of Examples 11-12, wherein the electric heating element is a disc heating element.

[0114] Example 14 The replaceable cartridge of any one of Examples 11 to 13, wherein the electric heating element comprises a heat sink or a heat reservoir.

[0115] Example 15 A replaceable cartridge according to any one of Examples 10 to 14 when dependent on claim 2, wherein the wick is a heating element of the at least one heating element.

[0116] Example 16. A replaceable cartridge according to any one of Examples 1 to 15, wherein the thermochromatic thermally conductive element comprises a body, preferably wherein the thermochromatic thermally conductive element comprises a layer of thermochromatic material printed on the body.

[0117] Example 17. The replaceable cartridge of example 16, wherein the body comprises a porous ceramic.

[0118] Example 18 The replaceable cartridge of any one of Examples 1-17, wherein the thermochromatic thermally conductive element comprises a porous layer.

[0119] Example 19. The replaceable cartridge of Example 18, wherein the porous layer comprises a temperature sensitive material.

[0120] Example 20. The replaceable cartridge of example 19, wherein the temperature sensitive material is a positive temperature coefficient material or a negative temperature coefficient material.

[0121] Example 21 The replaceable cartridge of any one of Examples 2-20 when dependent on Example 2, wherein the thermochromatic thermally conductive element is in thermal contact with the wick.

[0122] Example 22 The replaceable cartridge of any one of Examples 10-21 when dependent on Example 10, wherein the thermochromatic thermally conductive element is in thermal contact with at least one heating element.

[0123] Example 23 The replaceable cartridge of any one of Examples 1 to 22, wherein the color change is irreversible.

[0124] Example 24 The replaceable cartridge of any one of Examples 1-23, wherein the thermochromatic thermally conductive element comprises an absorbent material.

[0125] Example 25. A replaceable cartridge according to any one of Examples 2 to 24 when dependent on Example 2, wherein the wick has a peripheral wall extending along the longitudinal axis of the replaceable cartridge, and the thermochromatic thermally conductive element is disposed at least partially around the peripheral wall of the wick.

[0126] Example 26. A replaceable cartridge as described in any one of Examples 1 to 25, further comprising a housing having a transparent portion, the transparent portion allowing the thermochromatic thermally conductive element to be viewed from outside the replaceable cartridge.

[0127] Example 27. A replaceable cartridge according to any one of Examples 1 to 26, wherein the liquid aerosol-forming substrate comprises nicotine.

[0128] Example 28. A replaceable cartridge as described in Example 27, wherein the liquid aerosol-forming substrate comprises a nicotine salt matrix.

[0129] Example 29. A replaceable cartridge according to any one of Examples 1 to 28, wherein the liquid aerosol-forming substrate comprises a plant-derived material.

[0130] Example 30. The replaceable cartridge of any one of Examples 29, wherein the plant-derived material is a homogenized plant-derived material.

[0131] Example 31. A replaceable cartridge according to any one of Examples 1 to 30, wherein the liquid aerosol-forming substrate comprises a non-tobacco material.

[0132] Example 32 An aerosol-generating article as described in any one of Examples 1 to 31, wherein the liquid aerosol-forming substrate comprises a tobacco material.

[0133] Example 33. A replaceable cartridge according to any one of Examples 1 to 32, wherein the liquid aerosol-forming substrate comprises water.

[0134] Example 34. The replaceable cartridge of any one of Examples 1 to 33, wherein the liquid aerosol-forming substrate comprises an aerosol forming body.

[0135] Example 35 The replaceable cartridge of example 34, wherein the aerosol former comprises glycerin, or propylene glycol, or both glycerin and propylene glycol.

[0136] Example 36. A reusable aerosol generation device comprising a power source configured to provide power to a vaporizer of a replaceable cartridge according to any one of Examples 1 to 35.

[0137] Example 37. A reusable aerosol generating device as described in Example 36, wherein a power source is configured to be electrically connected to the vaporizer of the replaceable cartridge as described in any one of Examples 1 to 35.

[0138] Example 38. A reusable aerosol generating device according to any one of Examples 36 to 37, further comprising a control unit.

[0139] Example 39. A reusable aerosol generating device according to any one of Examples 36 to 38, further comprising a device housing.

[0140] Example 40. A reusable aerosol generating device according to any one of Examples 36 to 39, further comprising an apparatus air inlet and an apparatus air outlet.

[0141] Example 41. A reusable aerosol generating device as described in Example 40 when dependent on Example 39, wherein the device housing comprises a device air inlet and a device air outlet.

[0142] Example 42. A reusable aerosol generating device described in any one of Examples 36 to 41 when dependent on Example 38, wherein the control unit is configured to control the power supply from the power source to the vaporizer of the replaceable cartridge described in any one of Examples 1 to 35.

[0143] Example 43. A reusable aerosol generating device described in any one of Examples 36 to 42, further comprising a sensor configured to detect airflow indicative of a user taking a puff.

[0144] Example 44. A reusable aerosol generating device according to any one of Examples 36 to 43, further comprising at least one electrical connector.

[0145] Example 45. A reusable aerosol generating device as described in any one of Examples 44, wherein at least one electrical connector comprises an external plug or socket, such as a USB plug or USB socket.

[0146] Example 46 An aerosol generating system comprising the replaceable cartridge according to any one of Examples 1 to 35 and the reusable aerosol generating device according to any one of Examples 36 to 45.

[0147] Example 47. An aerosol generation system as described in Example 46 when dependent on Example 38, wherein the control unit is configured to determine or estimate the temperature of the vaporizer and to stop the supply of power from the power source to the vaporizer when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0148] Example 48. The aerosol generation system of Example 47, wherein the temperature of the vaporizer is determined or estimated as a function of the conductivity of a component of the vaporizer.

[0149] Example 49: An aerosol generation system as described in Example 48 when dependent on Example 10, wherein the vaporizer component is at least one heating element.

[0150] Example 50. An aerosol generation system according to any one of Examples 48-49, wherein the vaporizer components and the control unit form a feedback loop.

[0151] Example 51 An aerosol generation system described in any one of Examples 46 to 50 when dependent on Example 38, wherein the control unit is configured to determine or estimate the temperature of the thermochromatic thermally conductive element, and to stop the supply of power from the power source to the vaporizer when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0152] Example 52. The aerosol generating system of Example 51, wherein the temperature of the thermochromatic thermally conductive element is determined or estimated as a function of the electrical conductivity of the components of the thermochromatic thermally conductive element.

[0153] Example 53 An aerosol generating system according to Example 52 when dependent on Example 18, wherein the component of the thermochromatic thermally conductive element is a porous layer.

[0154] Example 54: An aerosol generating system described in any one of Examples 52 to 53, wherein the components of the thermochromatic thermally conductive element and the control unit form a feedback loop.

[0155] Example 55 An aerosol generating system described in any one of Examples 47 to 54, wherein the predetermined threshold value stored in the control unit is substantially the same as the temperature threshold value of the thermochromatic thermally conductive element.

[0156] Example 56: An aerosol generating system described in any one of Examples 47 to 55, wherein the aerosol generating device is provided with a display or an audible alarm, and the control unit is configured to change the warning signal issued by the display or audible alarm when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0157] Example 57 An aerosol generation system described in any one of Examples 47 to 56, wherein the control unit comprises an electrical circuit that may be operable to permanently disable the replaceable cartridge when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

[0158] These and other features and advantages of the present invention will become more apparent in the light of the following detailed description of preferred embodiments, given by way of illustrative and non-limiting example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0159] [Figure 1] FIG. 1 shows a replaceable cartridge with a thermochromatic heat conductive element. [Diagram 2] FIG. 2 illustrates the replaceable cartridge of FIG. 1 when the thermochromatic heat conductive element has undergone a color change. [Diagram 3] FIG. 3 illustrates an aerosol generation system including the replaceable cartridge of FIGS. [Figure 4] FIG. 4 illustrates the aerosol generating system of FIG. 3 when the thermochromatic heat conductive element undergoes a color change and the display issues a warning signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0160] 1 shows a replaceable cartridge 1 comprising a liquid storage portion 2, a vaporizer 10, and a thermochromatic heat-conductive element 20. The liquid storage portion 2 contains a liquid aerosol-forming substrate 3.

[0161] The vaporizer 10 is configured to vaporize a liquid aerosol-forming substrate 3 and comprises a wick 11 configured to absorb the liquid aerosol-forming substrate 3 and deliver the liquid aerosol-forming substrate 3 to an area of ​​the vaporizer 10 where it is vaporized. In this embodiment, the vaporizer 10 comprises a disk resistive heating element 12 in thermal contact with the wick 11. The resistive heating element 12 is electrically connected to a first electrical pin 13 and a second electrical pin 14 configured to receive an electric current from a power supply. The wick 11 comprises a thermally conductive material, such as a thermally conductive porous ceramic. Hence, heat generated by the resistive heating element 12 when an electric current is supplied is transferred by thermal conduction to the wick 11, and the liquid aerosol-forming substrate 3 absorbed by the wick 11 is vaporized.

[0162] The thermochromatic heat conductive element 20 is in thermal contact with the vaporizer 10. In particular, in the embodiment of Figure 1, the wick 11 includes a peripheral wall 15 that extends along a longitudinal axis of the replaceable cartridge 1, and the thermochromatic heat conductive element 20 is in thermal contact with the wick 11 and is disposed partially around the peripheral wall 15 of the wick 11.

[0163] 1, the liquid storage portion 2 is annular and defines an inner passage 7 surrounded by the liquid storage portion 2. The cartridge air outlet 4 is disposed at a downstream end of the inner passage 7 and the vaporizer 10 is disposed at an upstream end of the inner passage 7.

[0164] The replaceable cartridge 1 has a cartridge air inlet 5, and the cartridge air inlet 5 and the cartridge air outlet 4 are arranged to define an airflow path between the cartridge air inlet 5 and the cartridge air outlet 4. The airflow path passes through the wick 11 such that the liquid aerosol-forming substrate 3 vaporized in the wick 11 is entrained in air entering the replaceable cartridge 1 through the cartridge air inlet 5 and flows along the inner passage 7 towards the cartridge air outlet 4. The cartridge air outlet 4 allows the vaporized liquid aerosol-forming substrate 3 to exit.

[0165] Thermochromatic thermally conductive element 20 comprises a body 21 comprising a porous ceramic and a layer of thermochromatic material printed on the body 22. Thermochromatic thermally conductive element 20 also comprises a porous layer (not shown) comprising a temperature sensitive material.

[0166] 2 illustrates the replaceable cartridge 1 of FIG. 1 when the liquid storage portion 2 contains a reduced amount of liquid aerosol-forming substrate 3. In such a case, when the replaceable cartridge 1 is being used, an insufficient amount of liquid aerosol-forming substrate 3 is absorbed by and heated in the wick 11, which causes the vaporizer 10 to overheat. Because the thermochromatic heat-conductive element 20 is in thermal contact with the wick 11 and the resistive heating element 12, the temperature of the thermochromatic heat-conductive element 20 increases. The thermochromatic heat-conductive element 20 has a temperature threshold above which the thermochromatic heat-conductive element 20 undergoes a color change. The color characteristics of the thermochromatic heat-conductive element 20 are selected such that the thermochromatic heat-conductive element 20 undergoes a color change when the temperature of the thermochromatic heat-conductive element 20 corresponds to a temperature of the vaporizer 10 (such as the temperature of the wick 11 or the resistive heating element 12) at which the vaporizer 10 overheats.

[0167] Thus, at the point in Fig. 2 where an insufficient amount of liquid aerosol-forming substrate 3 leads to overheating of wick 11 and resistive heating element 12, thermochromatic thermally conductive element 20 undergoes a color change, which is represented by a dot in Fig. 2. The color change is interpreted by the user as an indication that replaceable cartridge 1 is no longer suitable to provide a satisfactory user experience. The user may then discard replaceable cartridge 1 and replace it with a new cartridge in the aerosol generating system.

[0168] In the embodiment of Figure 2, the replaceable cartridge 1 comprises a housing 6 with a transparent portion that allows the thermochromatic thermally conductive element 20 to be seen from the exterior of the replaceable cartridge 1. In Figure 2, the transparent portion is the outer peripheral wall of the housing 6.

[0169] Figure 3 illustrates an aerosol generation system 200 comprising the replaceable cartridge 1 of Figures 1 and 2 and a reusable aerosol generation device 100. The reusable aerosol generation device 100 comprises a power source 101 configured to provide electrical current to the resistive heating element 12 via the first electrical pin 13 and the second electrical pin 14.

[0170] The aerosol generating device 100 comprises a control unit 102 configured to control the supply of electrical current from a power source 101 to the resistive heating element 12 .

[0171] The power supply 101 and the control unit 102 are all contained within the device housing 107. The control unit 102 is disposed at the proximal end of the device 100. The electrical connector 103 is disposed at the distal end of the device housing 107.

[0172] The control unit 102 comprises a DC / AC inverter including a class D power amplifier. The control unit 102 is also configured to control the recharging of the power source 101 from the electrical connector 103. The control unit 102 further comprises a sensor (not shown) configured to sense when a user is inhaling the aerosol generation system 200.

[0173] The control unit 102 is configured to determine or estimate the temperature of the vaporizer 10, or the thermochromatic thermally conductive element 20, or both the vaporizer 10 and the thermochromatic thermally conductive element 20, and to stop supplying current from the power source 101 to the vaporizer 10 when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit 102.

[0174] The aerosol generating device 100 comprises a display 104. The control unit 102 is configured to modify a warning signal emitted by the display 104 when the determined or estimated temperature exceeds a predefined threshold stored in the control unit 102.

[0175] Figure 4 shows the aerosol generating system of Figure 3 when there is an insufficient amount of liquid aerosol-forming substrate 3 in the liquid storage portion 2. This leads to overheating of the vaporizer 10. As mentioned above, the thermally conductive element 20 undergoes a color change and the display 104 emits a warning signal, represented by a blinking line in Figure 4. Thus, two independent systems for indicating overheating of the vaporizer 10 are provided in the aerosol generating system 200. This improves the robustness of the protection against overheating.

[0176] Advantageously, the predetermined temperature threshold stored in the control unit 102 is substantially the same as the temperature threshold of the thermochromatic thermally conductive element 20. This may provide a consistent dual indication of the compatibility of the replaceable cartridge by the color change of the thermochromatic thermally conductive element 20 and the warning signal emitted by the display 104.

[0177] Furthermore, because the control unit 102 stops supplying current from the power source 101 to the vaporizer 10, the risk of using the aerosol generation system 200 when the vaporizer 10 overheats is further reduced, even if the user overlooks or ignores the color change of the thermochromatic thermally conductive element 20 and the warning signal on the display 104.

Claims

1. A replaceable cartridge, a liquid reservoir containing a liquid aerosol-forming substrate; a vaporizer configured to vaporize the liquid aerosol-forming substrate, the vaporizer comprising a wick configured to absorb the liquid aerosol-forming substrate; a thermochromatic heat-conducting element in thermal contact with said vaporizer, said thermochromatic heat-conducting element having a temperature threshold above which it undergoes a color change; - a cartridge air inlet; a cartridge air outlet, wherein the cartridge air inlet and the cartridge air outlet are arranged to define an airflow path between the cartridge air inlet and the cartridge air outlet, the cartridge air outlet being configured to allow vaporized liquid aerosol-forming substrate to exit, and the thermochromatic thermally conductive element comprising a body.

2. 2. The replaceable cartridge of claim 1, wherein the liquid storage portion is annular and defines an inner passage surrounded by the liquid storage portion, the air flow path comprises the inner passage, and the cartridge air outlet is located at a downstream end of the inner passage.

3. 3. The replaceable cartridge of claim 2, wherein a vaporizer is disposed at the upstream end of the inner passage.

4. The replaceable cartridge of claim 1 , wherein the thermochromatic thermally conductive element comprises a layer of thermochromatic material printed on the body.

5. The replaceable cartridge of claim 1 , wherein the body comprises a porous ceramic.

6. The replaceable cartridge of claim 1 , wherein the thermochromatic thermally conductive element comprises a porous layer, the porous layer comprising a temperature-sensitive material.

7. The replaceable cartridge of claim 1 , wherein the wick comprises a thermally conductive material.

8. The replaceable cartridge of claim 1 , wherein the thermochromatic thermally conductive element comprises an absorbent material.

9. 2. The replaceable cartridge of claim 1, wherein the wick includes a peripheral wall extending along a longitudinal axis of the replaceable cartridge, and the thermochromatic thermally conductive element is disposed at least partially around the peripheral wall of the wick.

10. The replaceable cartridge of claim 1 , wherein the color change is irreversible.

11. - a replaceable cartridge according to claim 1; a reusable aerosol generator comprising a power source configured to provide power to said vaporizer.

12. 12. The aerosol generation system of claim 11, wherein the aerosol generation device comprises a control unit configured to control the supply of power from the power source to the vaporizer.

13. 13. The aerosol generating system of claim 12, wherein the control unit is configured to determine or estimate the temperature of the vaporizer, or the thermochromatic thermal conductive element, or both the vaporizer and the thermochromatic thermal conductive element, and to stop power supply from the power source to the vaporizer when the determined or estimated temperature exceeds a predetermined threshold stored in the control unit.

14. 14. The aerosol generating system of claim 13, wherein the aerosol generating device is provided with a display or an audible alarm, and the control unit is configured to change the warning signal emitted by the display or audible alarm when the determined or estimated temperature exceeds the predetermined threshold stored in the control unit.

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