Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
  • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
  • H05B6/108—Induction heating apparatus, other than furnaces, for specific applications using a susceptor for heating a fluid
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
  • A24F40/46—Shape or structure of electric heating means
  • A24F40/465—Shape or structure of electric heating means specially adapted for induction heating
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/20—Devices using solid inhalable precursors
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
  • A24F40/53—Monitoring, e.g. fault detection
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
  • A24F40/57—Temperature control
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/28—Coils; Windings; Conductive connections
  • H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/06—Control, e.g. of temperature, of power
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
  • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/36—Coil arrangements
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/36—Coil arrangements
  • H05B6/44—Coil arrangements having more than one coil or coil segment

Definitions

• a resistive heating element such as a heating blade is inserted into or around the aerosol-forming substrate when the article is received in the aerosol-generating device.
• an inductive heater is used rather than a resistive heating element.
• the inductive heater typically comprises an inductor coil forming part of the aerosol-generating device and a susceptor arranged such that it is in thermal proximity to the aerosol-forming substrate.
• the inductor generates a varying magnetic field to generate eddy currents and hysteresis losses in the susceptor, causing the susceptor to heat up, thereby heating the aerosol-forming substrate.
• Inductive heating allows aerosol to be generated without exposing the heater to the aerosol generating article. This can improve the ease with which the heater may be cleaned.
• an aerosol-generating device comprising: an inductive heating arrangement configured to heat an aerosol-forming substrate, the inductive heating arrangement comprising: a susceptor arrangement that is heatable by penetration with a varying magnetic field to heat the aerosol-forming substrate, a first LC circuit, the first LC circuit at least comprising a first inductor coil and a first capacitor, wherein the first LC circuit has a first resonance frequency, and a second LC circuit, the second LC circuit at least comprising a second inductor coil and a second capacitor, wherein the second LC circuit has a second resonance frequency different from the first resonance frequency of the first LC circuit.
• the resonance frequency of an LC circuit depends upon the inductance of the inductor coil of the LC circuit and upon the capacitance of the capacitor of the LC circuit.
• the first resonance frequency being different from the second resonance frequency means that the inductance of the first inductor coil is different from the inductance of the second inductor coil.
• the first resonance frequency being different from the second resonance frequency means that the capacitance of the first capacitor is different from the capacitance of the second capacitor.
• the first resonance frequency being different from the second resonance frequency means that the inductance of the first inductor coil is different from the inductance of the second inductor coil and the capacitance of the first capacitor is different from the capacitance of the second capacitor.
• the aerosol-generating device may further comprise a controller, wherein the controller is configured to drive the first LC circuit with a first AC current for generating a first alternating magnetic field for heating a first portion of the susceptor arrangement, wherein the controller is configured to drive the second LC circuit with a second AC current for generating a second alternating magnetic field for heating a second portion of the susceptor arrangement, and wherein the controller is configured to supply the first AC current with a frequency corresponding to the first resonance frequency of the first LC circuit and to supply the second AC current with a frequency corresponding to the second resonance frequency of the second LC circuit.
• the controller may be configured to supply the first AC current to the first LC circuit during a second phase to decrease the temperature of the first portion of the susceptor arrangement from the first operating temperature to a second operating temperature, wherein the controller is configured to supply the first AC current with a frequency different from the first resonance frequency of the first LC circuit during the second phase.
• the controller may be configured to supply the second AC current to the second LC circuit during the first phase to increase the temperature of the second portion of the susceptor arrangement from an initial temperature to a third operating temperature, lower than the first operating temperature, wherein the controller is configured to supply the second AC current with a frequency different from the second resonance frequency of the second LC circuit during the first phase.
• the controller may be configured to supply the second AC current to the second LC circuit during the second phase to increase the temperature of the second portion of the susceptor arrangement from the third operating temperature to a fourth operating temperature, higher than the second operating temperature, wherein the controller is configured to supply the second AC current with a frequency corresponding to the second resonance frequency of the second LC circuit during the second phase.
• the aerosol-generating device may further comprise a power supply for providing power to the inductive heating arrangement.
• the microcontroller may be configured to utilize the clock frequency of the microcontroller as the alternating frequency of the first AC current or of the second AC current.
• the aerosol-generating device may further comprise an oscillator for generating one or both of the alternating frequency of the first AC current and of the second AC current.
• the controller may further comprise an oscillator for generating one or both of the alternating frequency of the first AC current and of the second AC current.
• an aerosol-generating system comprising an aerosol-generating device according to the invention and an aerosol-generating article comprising an aerosol-forming substrate.
• a method of controlling an aerosol generating device comprising: an inductive heating arrangement configured to heat an aerosol-forming substrate, the inductive heating arrangement comprising: a susceptor arrangement that is heatable by penetration with a varying magnetic field to heat the aerosol-forming substrate, a first LC circuit, the first LC circuit at least comprising a first inductor coil and a first capacitor, wherein the first LC circuit has a first resonance frequency, and a second LC circuit, the second LC circuit at least comprising a second inductor coil and a second capacitor, wherein the second LC circuit has a second resonance frequency different from the first resonance frequency of the first LC circuit; and a controller, wherein the controller is configured to drive the first LC circuit and to drive the second LC circuit, the method comprising: driving the first LC circuit with a first AC current for generating a first alternating magnetic field for heating a first portion of the susceptor arrangement; driving the second LC circuit with a
• the first AC current may be supplied to the first LC circuit during a first phase to increase the temperature of the first portion of the susceptor arrangement from an initial temperature to a first operating temperature, wherein the first AC current is supplied with a frequency corresponding to the first resonance frequency of the first LC circuit during the first phase.
• the second AC current may be supplied to the second LC circuit during the second phase to increase the temperature of the second portion of the susceptor arrangement from the third operating temperature to a fourth operating temperature, higher than the second operating temperature, wherein the second AC current is supplied with a frequency corresponding to the second resonance frequency of the second LC circuit during the second phase.
• an aerosol-generating article refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol.
• an aerosol-generating article may be an article that generates an aerosol that is directly inhalable by the user drawing or puffing on a mouthpiece at a proximal or user-end of the system.
• An aerosol-generating article may be disposable.
• An article comprising an aerosol-forming substrate comprising tobacco may be referred to herein as a tobacco stick.
• aerosol-generating device refers to a device that interacts with an aerosol-forming substrate to generate an aerosol.
• aerosol-generating system refers to the combination of an aerosol-generating device with an aerosol-generating article.
• the aerosol-generating article and the aerosol-generating device cooperate to generate a respirable aerosol.
• the term“varying current” includes any currents that vary with time to generate a varying magnetic field.
• the term“varying current” is intended to include alternating currents. Where the varying current is an alternating current, the alternating current generates an alternating magnetic field.
• the term "length" refers to the major dimension in a longitudinal direction of an aerosol-generating device or an aerosol-generating article, or a component of the aerosol generating device or the aerosol-generating article.
• width refers to the major dimension in a transverse direction of an aerosol-generating device or an aerosol-generating article, or a component of the aerosol generating device or the aerosol-generating article, at a particular location along its length.
• thickness refers to the dimension in a transverse direction perpendicular to the width.
• transverse cross-section is used to describe the cross-section of an aerosol-generating device or an aerosol-generating article, or a component of the aerosol generating device or the aerosol-generating article, in a direction perpendicular to the longitudinal direction at a particular location along its length.
• proximal refers to a user end, or mouth end of the aerosol generating device or aerosol-generating article.
• the proximal end of a component of an aerosol generating device or an aerosol-generating article is the end of the component closest to the user end, or mouth end of the aerosol-generating device or the aerosol-generating article.
• distal refers to the end opposite the proximal end.
• the first phase may have a predetermined duration.
• the second phase may have a predetermined duration.
• the duration of the first phase and the duration of the second phase may be the same.
• the duration of the second phase may be different to the duration of the first phase.
• this may enable the system to heat a first portion of aerosol-forming substrate and a second portion of aerosol-forming substrate for different times.
• the duration of the second phase may be less than the duration of the first phase.
• the duration of the second phase may be greater than the duration of the first phase.
• the duration of the first phase may be between about 50 seconds and about 200 seconds.
• the duration of the second phase is between about 50 seconds and about 200 seconds.
• the combined duration of the first phase and the second phase may be between about 100 seconds and about 400 seconds.
• the combined duration of the first phase and the second phase may be between about 150 seconds and about 300 seconds.
• the system further comprises a puff detector configured to detect when a user takes a puff on the system to receive aerosol.
• the duration of the first phase may be based on a first predetermined number of puffs detected by the puff detector.
• the first predetermined number of puffs may be between 2 and 5.
• the duration of the second phase may be based on a second predetermined number of puffs detected by the puff detector.
• the second predetermined number of puffs may be between 2 and 5.
• the combined duration of the first phase and the second phase may be based on a combined predetermined number of puffs detected by the puff detector.
• the combined predetermined number of puffs may be between 3 and 10 user puffs.
• the first phase ends after a first maximum number of puffs is detected or earlier if a first maximum duration is reached.
• the first maximum number of puffs may be between 2 and 5, and the first maximum duration is between 50 seconds and about 200 seconds.
• the wherein the second phase ends after a second maximum number of puffs is detected or earlier if a second maximum duration is reached.
• the second maximum number of puffs may be between 2 and 5, and the second maximum duration may be between 50 seconds and about 200 seconds.
• the second AC current may be controlled to increase the temperature of the second portion of the susceptor arrangement from an initial temperature in accordance with a second temperature profile.
• the second temperature profile is a predetermined desired temperature of the second portion of the susceptor arrangement over time.
• the second AC current is adjusted to adjust the temperature of the second portion of the susceptor arrangement to the temperature specified by the second temperature profile at that time.
• the first operating temperature profile is substantially constant. In some embodiments, the first operating temperature profile varies with time.
• the second operating temperature profile is substantially constant. In some embodiments, the second operating temperature profile varies with time.
• the first operating temperature profile in at least a portion of the first phase, is greater than the second operating temperature profile. In these embodiments, in at least a portion of the first phase, the first operating temperature profile is greater than the second operating temperature profile by at least about 50 degrees Celsius. The first operating temperature profile may be greater than the second operating temperature profile through the entire first phase.
• the first operating temperature profile and the second operating temperature profile are substantially the same. In some embodiments, in the second phase, the second operating temperature profile is within about 5 degrees Celsius of the first operating temperature profile.
• the second operating temperature profile in at least a portion of the second phase, is greater than the first operating temperature profile. In these embodiments, in the second phase, the second operating temperature profile may be greater than the first operating temperature profile by no more than about 50 degrees Celsius.
• the first operating temperature profile is substantially constant during at least a portion of the first phase.
• the first operating temperature profile may be constant during the first phase.
• the first operating temperature profile is substantially constant during at least a portion of the second phase.
• the first operating temperature profile may be constant during the second phase.
• the second operating temperature profile is substantially constant during at least a portion of the second phase.
• the second operating temperature profile may be constant during the second phase.
• the first operating temperature profile may be between about 180 degrees Celsius and 300 degrees Celsius during at least a portion of the first phase.
• the first operating temperature profile may be between about 160 degrees Celsius and about 260 degrees Celsius during at least a portion of the second phase.
• the second operating temperature profile may be between about 180 degrees Celsius and about 300 degrees Celsius during at least a portion of the second phase.
• the susceptor arrangement may have any suitable form.
• the susceptor arrangement may have a unitary structure.
• the susceptor arrangement may comprise a plurality of unitary structures.
• the susceptor arrangement may be elongate.
• the susceptor arrangement may have any suitable transverse cross-section.
• the susceptor arrangement may have a circular, elliptical, square, rectangular, triangular or other polygonal transverse cross-section.
• the susceptor arrangement may be configured to penetrate an aerosol-forming substrate when an aerosol-forming substrate is received by the device.
• the internal heating element is preferably configured to be insertable into an aerosol forming substrate.
• An internal heating element may be in the form of a blade.
• An internal heating element may be in the form of a pin.
• An internal heating element may be in the form of a cone.
• the aerosol-generating device comprises a device cavity for receiving an aerosol forming substrate, preferably the internal heating element extends into the device cavity.
• a susceptor arrangement may be an external heating element.
• the term“external heating element” refers to a heating element configured to heat an outer surface of an aerosol-forming substrate.
• An external heating element is preferably configured to at least partially surround an aerosol forming substrate when the aerosol-forming substrate is received by the aerosol-generating device.
• the susceptor arrangement may be configured to heat an outer surface of the aerosol-forming substrate when the aerosol-forming substrate is received in a susceptor arrangement cavity.
• the susceptor arrangement may be configured to substantially circumscribe an aerosol forming substrate when an aerosol-forming substrate is received by the device.
• the susceptor arrangement may comprise a cavity for receiving aerosol-forming substrate.
• the susceptor arrangement may comprise an outer side and an inner side, opposite the outer side.
• the inner side may at least partially define the susceptor arrangement cavity for receiving aerosol-forming substrate.
• the first portion of the susceptor arrangement may be tubular and define a portion of a susceptor arrangement cavity.
• the second portion of the susceptor arrangement may be tubular and define a portion of a susceptor arrangement cavity.
• the susceptor arrangement comprises a plurality of inner cavities for receiving aerosol-forming substrate.
• the inner cavity of the first portion of the susceptor arrangement may form a first cavity of the susceptor arrangement, and the inner cavity of the second portion of the susceptor arrangement may form a second cavity of the susceptor arrangement.
• the susceptor arrangement comprises a single inner cavity for receiving aerosol-forming substrate.
• the inner cavity of the first portion of the susceptor arrangement defines a portion of the single inner cavity of the susceptor arrangement
• the inner cavity of the second portion of the susceptor arrangement defines a second portion of the single inner cavity of the susceptor arrangement.
• the susceptor arrangement is a tubular susceptor arrangement. An inner surface of the tubular susceptor arrangement may define the susceptor arrangement cavity.
• the susceptor arrangement may at least partially circumscribe the device cavity.
• the susceptor arrangement cavity may be aligned with the device cavity.
• the susceptor arrangement comprises at least one internal heating element, and at least one external heating element.
• the susceptor arrangement comprises at least one susceptor.
• the susceptor arrangement may comprise a single susceptor.
• the susceptor arrangement may consist of a single susceptor.
• the first portion of the susceptor arrangement may comprise a first susceptor.
• the second portion of the susceptor arrangement may comprise a second susceptor.
• the term“susceptor” refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When a susceptor is located in a varying magnetic field, the susceptor is heated. Heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.
• a susceptor may comprise any suitable material.
• a susceptor may be formed from any material that can be inductively heated to a temperature sufficient to aerosolise an aerosol forming substrate. Preferred susceptors may be heated to a temperature in excess of about 250 degrees Celsius. Preferred susceptors may be formed from an electrically conductive material. As used herein,“electrically conductive” refers to materials having an electrical resistivity of less than or equal to 1 x10 4 ohm metres (Q.m), at twenty degrees Celsius. Preferred susceptors may be formed from a thermally conductive material.
• thermally conductive material is used to describe a material having a thermal conductivity of at least 10 watts per metre Kelvin (W/(m.K)) at 23 degrees Celsius and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.
• W/(m.K) watts per metre Kelvin
• MTPS modified transient plane source
• Suitable materials for a susceptor include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel containing compounds, titanium, and composites of metallic materials. Some preferred susceptors comprise a metal or carbon. Some preferred susceptors comprise a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. Some preferred susceptors consists of a ferromagnetic material. A suitable susceptor may comprise aluminium. A suitable susceptor may consist of aluminium. A susceptor may comprise at least about 5 percent, at least about 20 percent, at least about 50 percent or at least about 90 percent of ferromagnetic or paramagnetic materials.
• a susceptor of the susceptor arrangement may have any suitable form.
• a susceptor may be elongate.
• a susceptor may have any suitable transverse cross-section.
• a susceptor may have a circular, elliptical, square, rectangular, triangular or other polygonal transverse cross-section.
• the first portion of the susceptor arrangement may be a tubular susceptor.
• the second portion of the susceptor arrangement may be a tubular susceptor.
• a tubular susceptor comprises an annular body defining an inner cavity.
• the susceptor cavity may be configured to receive aerosol-forming substrate.
• the susceptor cavity may be an open cavity.
• the susceptor cavity may be open at one end.
• the susceptor cavity may be open at both ends.
• each susceptor may be substantially identical.
• the second susceptor may be substantially identical to the first susceptor.
• Each susceptor may be formed from the same material.
• Each susceptor may have substantially the same shape and dimensions. Making each susceptor substantially identical to the other susceptors may enable each susceptor to be heated to substantially the same temperature, and heated at substantially the same rate, when exposed to a given varying magnetic field.
• the second susceptor differs to the first susceptor in at least one characteristic.
• the second susceptor may be formed from a different material than the first susceptor.
• the second susceptor may have a different shape and dimensions to the first susceptor.
• the second susceptor may have a length that is longer than the length of the first susceptor. Making each susceptor different to the other susceptors may enable each susceptor to be adapted to provide optimal heat for different aerosol-forming substrates.
• the first susceptor is an elongate tubular susceptor and the second susceptor is an elongate tubular susceptor.
• the first susceptor and the second susceptor may be substantially aligned. In other words, the first susceptor and the second susceptor may be coaxially aligned.
• the susceptor arrangement may comprise any suitable number of susceptors.
• the susceptor arrangement may comprise a plurality of susceptors.
• the susceptor arrangement may comprise at least two susceptors.
• the susceptor arrangement may comprise three, four, five or six susceptors.
• an intermediate element may be disposed between each adjacent pair of susceptors.
• a susceptor may comprise a susceptor layer provided on a support body.
• each of the first susceptor and the second susceptor may be formed from a support body and a susceptor layer.
• Arranging a susceptor in a varying magnetic field induces eddy currents in close proximity to the susceptor surface, in an effect that is referred to as the skin effect. Accordingly, it is possible to form a susceptor from a relatively thin layer of susceptor material, while ensuring the susceptor is effectively heated in the presence of a varying magnetic field.
• Making a susceptor from a support body and a relatively thin susceptor layer may facilitate manufacture of an aerosol generating article that is simple, inexpensive and robust.
• the support body may be formed from a material that is not susceptible to inductive heating.
• this may reduce heating of surfaces of the susceptor that are not in contact with an aerosol-forming substrate, where surfaces of the support body form surfaces of the susceptor that are not in contact with an aerosol-forming substrate.
• the support body may comprise an electrically insulative material.
• electrically insulative refers to materials having an electrical resistivity of at least 1 x10 4 ohm metres (Q.m), at twenty degrees Celsius.
• the support body may comprise a thermally insulative.
• thermally insulative material' is used to describe material having a bulk thermal conductivity of less than or equal to about 40 watts per metre Kelvin (W/(m.K)) at 23 degrees Celsius and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.
• W/(m.K) watts per metre Kelvin
• Forming the support body from a thermally insulative material may provide a thermally insulative barrier between the susceptor layer and other components of an inductive heating arrangement, such as an inductor coil circumscribing the susceptor arrangement.
• an inductive heating arrangement such as an inductor coil circumscribing the susceptor arrangement.
• this may reduce heat transfer between the susceptor and other components of an inductive heating system.
• the support body may be a tubular support body and the susceptor layer may be provided on an inner surface of the tubular support body. Providing the susceptor layer on the inner surface of the support body may position the susceptor layer adjacent an aerosol-forming substrate in the cavity of the susceptor arrangement, improving heat transfer between the susceptor layer and the aerosol-forming substrate.
• the first susceptor comprises a tubular support body formed from a thermally insulative material and a susceptor layer on an inner surface of the tubular support body.
• the second susceptor comprises a tubular support body formed from a thermally insulative material and a susceptor layer on an inner surface of the tubular support body.
• the susceptor may be provided with a protective outer layer, for example a protective ceramic layer or protective glass layer.
• a protective outer layer may improve the durability of the susceptor and facilitate cleaning of the susceptor.
• the protective outer layer may substantially surround the susceptor.
• the susceptor may comprise a protective coating formed from a glass, a ceramic, or an inert metal.
• the susceptor arrangement may comprise a separation between the first portion of the susceptor arrangement and the second portion of the susceptor arrangement.
• the separation may be any suitable size to thermally insulate the first portion of the susceptor arrangement from the second portion of the susceptor arrangement.
• the susceptor arrangement may comprise an intermediate element disposed between the first portion of the susceptor arrangement and the second portion of the susceptor arrangement.
• the intermediate element may be disposed in the separation between the first portion of the susceptor arrangement and the second portion of the susceptor arrangement.
• the intermediate element may extend between the first portion of the susceptor arrangement and the second portion of the susceptor arrangement.
• the intermediate element may contact an end of the first portion of the susceptor arrangement.
• the intermediate element may contact an end of the second portion of the susceptor arrangement.
• the intermediate element may be secured to an end of the first portion of the susceptor arrangement.
• the intermediate element may be secured to an end of the second portion of the susceptor arrangement.
• the intermediate element may connect the second portion of the susceptor arrangement to the first portion of the susceptor arrangement.
• the intermediate element may provide the susceptor arrangement with structural support.
• the intermediate element may enable the susceptor arrangement to be provided as a single unitary element that may be straightforward to remove and replace from an inductive heating arrangement.
• the intermediate element may have any suitable form.
• the intermediate element may have any suitable transverse cross-section.
• the intermediate element may have a circular, elliptical, square, rectangular, triangular or other polygonal transverse cross-section.
• the intermediate element may be tubular.
• a tubular intermediate element comprises an annular body defining an inner cavity.
• the intermediate element may be configured to enable gas to permeate from an outer side of the intermediate element into the inner cavity.
• the intermediate element cavity may be configured to receive a portion of an aerosol-generating article.
• the intermediate element cavity may be an open cavity.
• the intermediate element cavity may be open at one end.
• the intermediate element cavity may be open at both ends.
• the first portion of the susceptor arrangement and the second portion of the susceptor arrangement are tubular susceptors, and the intermediate element is a tubular intermediate element.
• the tubular first susceptor, the tubular second susceptor and the tubular intermediate element may be substantially aligned.
• the tubular first susceptor, the tubular intermediate element and the tubular second susceptor may be arranged end-to-end, in the form of a tubular rod.
• the inner cavities of the tubular first susceptor, the tubular intermediate element and the tubular second susceptor may be substantially aligned.
• the inner cavities of the tubular first susceptor, the tubular intermediate element and the tubular second susceptor may define the susceptor arrangement cavity.
• the intermediate element may be formed from any suitable material.
• the intermediate element is formed from a different material to the first portion of the susceptor arrangement and the second portion of the susceptor arrangement.
• An inductor coil may have any suitable form.
• an inductor coil may be a flat inductor coil.
• a flat inductor coil may be wound in a spiral, substantially in a plane.
• the inductor coil is a tubular inductor coil, defining an inner cavity.
• a tubular inductor coil is helically wound about an axis.
• An inductor coil may be elongate.
• an inductor coil may be an elongate tubular inductor coil.
• An inductor coil may have any suitable transverse cross-section.
• an inductor coil may have a circular, elliptical, square, rectangular, triangular or other polygonal transverse cross-section.
• the temperature sensor may be any suitable type of temperature sensor.
• the temperature sensor may be a thermocouple, a negative temperature coefficient resistive temperature sensor or a positive temperature coefficient resistive temperature sensor.
• the aerosol-forming substrate may comprise plant-based material.
• the aerosol-forming substrate may comprise tobacco.
• the aerosol-forming substrate may comprise a tobacco- containing material including volatile tobacco flavour compounds which are released from the aerosol-forming substrate upon heating.
• the aerosol-forming substrate may comprise a non tobacco material.
• the aerosol-forming substrate may comprise homogenised plant-based material.
• the aerosol-forming substrate may comprise homogenised tobacco material. Homogenised tobacco material may be formed by agglomerating particulate tobacco.
• the aerosol-forming substrate comprises a gathered crimped sheet of homogenised tobacco material.
• the term 'crimped sheet' denotes a sheet having a plurality of substantially parallel ridges or corrugations.
• the aerosol-generating segment comprises a plurality of aerosol-forming substrates
• the aerosol-forming substrates may be arranged end-to-end along an axis of the aerosol-generating segment.
• the aerosol-generating segment may comprise a separation between adjacent aerosol-forming substrates.
• the aerosol-generating article may have a total length between about 30 millimetres and about 100 millimetres. In some embodiments, the aerosol generating article has a total length of about 45 millimetres.
• the aerosol-generating article may have an outer diameter between about 5 millimetres and about 12 millimetres. In some embodiments, the aerosol-generating article may have an outer diameter of about 7.2 millimetres.
• the aerosol-generating segment preferably has an outer diameter that is about equal to the outer diameter of the aerosol-generating article.
• the outer diameter of the aerosol-generating segment may be between about 5 millimetres and about 12 millimetres. In one embodiment, the aerosol-generating segment may have an outer diameter of about 7.2 millimetres.
• the first portion of the susceptor arrangement may be arranged to heat a first portion of the aerosol-forming substrate.
• the first portion of the susceptor arrangement may be arranged to substantially circumscribe a first portion of the aerosol-forming substrate.
• the second portion of the susceptor arrangement may be arranged to heat a second portion of the aerosol-forming substrate.
• the second portion of the susceptor arrangement may be arranged to substantially circumscribe a second portion of the aerosol-forming substrate.
• the aerosol-generating article may comprise an outer wrapper.
• the outer wrapper may be formed from paper.
• the outer wrapper may be gas permeable at the aerosol-generating segment.
• the outer wrapper may comprise perforations or other air inlets at the interface between adjacent aerosol-forming substrates.
• the outer wrapper may comprise perforations or other air inlets at the separation. This may enable an aerosol-forming substrate to be directly provided with air that has not been drawn through another aerosol-forming substrate. This may increase the amount of air received by each aerosol-forming substrate. This may improve the characteristics of the aerosol generated from the aerosol-forming substrate.
• Figure 1 shows a schematic illustration of a susceptor arrangement according to an embodiment of this disclosure arranged between a pair of inductor coils
• Figure 2 shows a schematic illustration of a susceptor arrangement according to an embodiment of this disclosure arranged between a pair of inductor coils
• Figure 4 shows a perspective view of the susceptor arrangement of Figure 3;
• Figure 10 shows a graph of temperature over time for the susceptor arrangement of Figure 8.
• Figure 1 1 shows an illustrative circuit of an inductive heating arrangement
• Figure 12 shows an illustrative circuit for controlling the inductive heating arrangement
• Figure 13 shows an illustration of pulse width modulated signals for driving the inductive heating arrangement.
• FIG. 1 shows a schematic illustration of a susceptor arrangement 10 according to an embodiment of this disclosure.
• the susceptor arrangement 10 is an elongate, tubular element, having a circular transverse cross-section.
• the susceptor arrangement 10 comprises a first susceptor 12, a second susceptor 14, and a separation 15 between the first susceptor 12 and the second susceptor 14.
• the first susceptor 12 and the second susceptor 14 are each elongate, tubular elements having a circular transverse cross-section.
• the first susceptor 12 and the second susceptor 14 are coaxially aligned, end-to-end, along a longitudinal axis A-A.
• the susceptor arrangement 10 comprises a cylindrical cavity 20, open at both ends, defined by an inner surfaces of the first susceptor 12 and the second susceptor 14.
• the cavity 20 is configured to receive a portion of a cylindrical aerosol-generating article (not shown), comprising an aerosol-forming substrate, such that an outer surface of the aerosol-generating article may be heated by the first susceptor and the second susceptor, thereby heating the aerosol-forming substrate.
• the cavity 20 comprises three portions, a first portion 22 at a first end, defined by an inner surface of the tubular first susceptor 12, a second portion 24 at a second end, opposite the first end, defined by an inner surface of the tubular second susceptor 14, and an intermediate portion 26, bounded by the separation 15 between the first susceptor 12 and the second susceptor 14.
• the first susceptor 12 is arranged to heat a first portion of an aerosol-generating article received in the first portion 22 of the cavity
• the second susceptor 14 is arranged to heat a second portion of an aerosol-generating article received in the second portion 24 of the cavity 20.
• the separation 15 between the first susceptor 12 and the second susceptor 14 provides a space between the first susceptor 12 and the second susceptor 14 that is not heated by induction when exposed to a varying magnetic field generated by either the first inductor coil 32 or the second inductor coil 34. Furthermore, the separation 15 thermally insulates the second susceptor 14 from the first susceptor 12, such that there is a reduced rate of heat transfer between the first susceptor 12 and the second susceptor 14, compared to a susceptor arrangement in which the first susceptor and the second susceptor are arranged adjacent each other, in direct thermal contact.
• providing the separation 15 between the first susceptor 12 and the second susceptor 14 enables selective heating of the first portion 22 of the cavity 20 by the first susceptor 12 with minimal heating of the second portion 24 of the cavity 20, and enables selective heating of the second portion 24 of the cavity 20 by the second susceptor 14 with minimal heating of the first portion 22 of the cavity 20.
• indirectly securing the first susceptor 12 to the second susceptor 14 enables the susceptor arrangement to form a unitary structure.
• the intermediate element 16 thermally insulates the second susceptor 14 from the first susceptor 12, such that there is a reduced rate of heat transfer between the first susceptor 12 and the second susceptor 14, compared to a susceptor arrangement in which the first susceptor and the second susceptor are arranged adjacent each other, in direct thermal contact.
• the intermediate element 16 may also further reduce the rate of heat transfer between the first susceptor 12 and the second susceptor 14 compared to the separation 15 of the susceptor arrangement 10 of Figure 1.
• FIGS. 3 and 4 show schematic illustrations of the susceptor arrangement 120.
• the susceptor arrangement 120 comprises: a first susceptor 122, a second susceptor 124, a third susceptor 126, a first intermediate element 128 and a second intermediate element 130.
• the first intermediate element 128 is disposed between the first susceptor 122 and the second susceptor 124.
• the second intermediate element 130 is disposed between the second susceptor 124 and the third susceptor 126.
• each of the first susceptor 122, the second susceptor 124 and the third susceptor 126 are identical.
• Each susceptor 122, 124, 126 is an elongate tubular susceptor, defining an inner cavity.
• the elongate tubular susceptor arrangement 120 comprises an inner cavity 140.
• the susceptor arrangement cavity 140 is defined by the inner cavities of the susceptors 122, 124, 126 and the inner cavities of the intermediate elements 128, 130.
• the susceptor arrangement cavity 140 is configured to receive an aerosol-generating segment of the aerosol-generating article 200, as described in more detail below.
• the intermediate elements 128, 130 are formed from an electrically insulative and thermally insulative material. As such, the susceptors 122, 124, 126 are substantially electrically and thermally insulated from each other. The material of the intermediate elements 128, 130 is also substantially impermeable to gas. In this embodiment, the tubular susceptor arrangement 120 is substantially impermeable to gas from an outer surface to an inner surface defining the susceptor arrangement cavity 140.
• FIGS 5, 6 and 7 show schematic cross-sections of the aerosol-generating device 100 and the aerosol-generating article 200.
• the aerosol-generating device 100 comprises a substantially cylindrical device housing 102, with a shape and size similar to a conventional cigar.
• the device housing 102 defines a device cavity 104 at a proximal end.
• the device cavity 104 is substantially cylindrical, open at a proximal end, and substantially closed at a distal end, opposite the proximal end.
• the device cavity 104 is configured to receive the aerosol-generating segment 210 of the aerosol-generating article 200. Accordingly, the length and diameter of the device cavity 104 are substantially similar to the length and diameter of the aerosol-generating segment 210 of the aerosol-generating article 200.
• the aerosol-generating device 100 further comprises a power supply 106, in the form of a rechargeable nickel-cadmium battery, a controller 108 in the form of a printed circuit board including a microprocessor, an electrical connector 109, and the inductive heating arrangement 110.
• the power supply 106, controller 108 and inductive heating arrangement 110 are all housed within the device housing 102.
• the inductive heating arrangement 1 10 of the aerosol-generating device 100 is arranged at the proximal end of the device 100, and is generally disposed around the device cavity 104.
• the electrical connector 109 is arranged at a distal end of the device housing 109, opposite the device cavity 104.
• the inductive heating arrangement 110 comprises three inductive heating units, including a first inductive heating unit 112, a second inductive heating unit 1 14 and a third inductive heating unit 116.
• the first inductive heating unit 1 12, second inductive heating unit 1 14 and third inductive heating unit 1 16 are substantially identical.
• the second inductive heating unit 114 comprises a cylindrical, tubular second inductor coil 160, a cylindrical, tubular second flux concentrator 162 disposed about the second inductor coil 160 and a cylindrical, tubular second inductor unit housing 164 disposed about the second flux concentrator 162.
• the third inductive heating unit 116 comprises a cylindrical, tubular third inductor coil 170, a cylindrical, tubular third flux concentrator 172 disposed about the third inductor coil 170 and a cylindrical, tubular third inductor unit housing 174 disposed about the third flux concentrator 172.
• each inductive heating unit 112, 1 14, 1 16 forms a substantially tubular unit with a circular transverse cross-section.
• the flux concentrator extends over the proximal and distal ends of the inductor coil, such that the inductor coil is arranged within an annular cavity of the flux concentrator.
• each inductive heating unit housing extends over the proximal and distal ends of the flux concentrator, such that the flux concentrator and inductor coil are arranged within an annular cavity of the inductive heating unit housing.
• This arrangement enables the flux concentrator to concentrate the magnetic field generated by the inductor coil in the inner cavity of the inductor coil.
• This arrangement also enables the inductor unit housing to retain the flux concentrator and inductor coil within the inductor unit housing.
• the inductive heating arrangement 110 further comprises the susceptor arrangement 120.
• the susceptor arrangement 120 is disposed about the inner surface of the device cavity 104.
• the device housing 102 defines an inner surface of the device cavity 104.
• the inner surface of the device cavity is defined by the inner surface of the susceptor arrangement 120.
• the inductive heating units 112, 114, 1 16 are disposed about the susceptor arrangement 120, such that the susceptor arrangement 120 and the inductive heating units 1 12, 114, 1 16 are concentrically arranged about the device cavity 104.
• the first inductive heating unit 1 12 is disposed about the first susceptor 122, at a distal end of the device cavity 104.
• the second inductive heating unit 1 14 is disposed about the second susceptor 124, at a central portion of the device cavity 104.
• the third inductive heating unit 116 is disposed about the third susceptor 126, at a proximal end of the device cavity 104. It is envisaged that in some embodiments the flux concentrators may also extend into the intermediate elements of the susceptor arrangement, in order to further distort the magnetic fields generated by the inductor coils towards the susceptors.
• the first inductor coil 150 is connected to the controller 108 and the power supply 106, and the controller 108 is configured to supply a varying electric current, preferably an AC current, to the first inductor coil 150.
• a varying electric current preferably an AC current
• the first inductor coil 150 generates a varying magnetic field, which heats the first susceptor 122 by induction.
• the second inductor coil 160 is connected to the controller 108 and the power supply 106, and the controller 108 is configured to supply a varying electric current, preferably an AC current, to the second inductor coil 160.
• a varying electric current preferably an AC current
• the second inductor coil 160 When a varying electric current, preferably an AC current, is supplied to the second inductor coil 160, the second inductor coil 160 generates a varying magnetic field, which heats the second susceptor 124 by induction.
• the first inductor coil 170 is connected to the controller 108 and the power supply 106, and the controller 108 is configured to supply a varying electric current, preferably an AC current, to the third inductor coil 170.
• a varying electric current preferably an AC current
• the third inductor coil 170 When a varying electric current, preferably an AC current, is supplied to the third inductor coil 170, the third inductor coil 170 generates a varying magnetic field, which heats
• the device housing 102 also defines an air inlet 180 in close proximity to the distal end of the device cavity 106.
• the air inlet 180 is configured to enable ambient air to be drawn into the device housing 102.
• An airflow pathway 181 is defined through the device, between the air inlet 180 and an air outlet in the distal end of the device cavity 104, to enable air to be drawn from the air inlet 180 into the device cavity 104.
• the aerosol-generating article 200 is generally in the form of a cylindrical rod, having a diameter similar to the inner diameter of the device cavity 104.
• the aerosol-generating article 200 comprises a cylindrical cellulose acetate filter plug 204 and a cylindrical aerosol-generating segment 210 wrapped together by an outer wrapper 220 of cigarette paper.
• the filter plug 204 is arranged at a proximal end of the aerosol-generating article 200, and forms the mouthpiece of the aerosol-generating system on which a user draws to receive aerosol generated by the system.
• the aerosol-generating segment 210 is arranged at a distal end of the aerosol-generating article 200, and has a length substantially equal to the length of the device cavity 104.
• the aerosol-generating segment 210 comprises a plurality of aerosol-forming substrates, including: a first aerosol-forming substrate 212 at a distal end of the aerosol-generating article 200, a second aerosol-forming substrate 214 adjacent the first aerosol-forming substrate 212, and a third aerosol-forming substrate 216 at a proximal end of the aerosol-generating segment 210, adjacent the second aerosol-forming substrate 216. It will be appreciated that in some embodiments two or more of the aerosol-forming substrates may be formed from the same materials.
• each of the aerosol-forming substrates 212, 214, 216 is different.
• the first aerosol-forming substrate 212 comprises a gathered and crimped sheet of homogenised tobacco material, without additional flavourings.
• the second aerosol-forming substrate 214 comprises a gathered and crimped sheet of homogenised tobacco material including a flavouring in the form of menthol.
• the third aerosol-forming substrate comprises a flavouring in the form of menthol, and does not comprise tobacco material or any other source of nicotine.
• Each of the aerosol forming substrates 212, 214, 216 also comprises further components, such as one or more aerosol formers and water, such that heating the aerosol-forming substrate generates an aerosol with desirable organoleptic properties.
• the proximal end of the first aerosol-forming substrate 212 is exposed, as it is not covered by the outer wrapper 220. In this embodiment, air is able to be drawn into the aerosol-generating segment 210 via the proximal end of the first aerosol-forming substrate 212, at the proximal end of the article 200.
• first aerosol-forming substrate 212, the second aerosol-forming substrate 214 and the third aerosol-forming substrate 216 are arranged end-to-end.
• a separation may be provided between the first aerosol forming substrate and the second aerosol-forming substrate, and a separation may be provided between the second aerosol-forming substrate and the third aerosol-forming substrate.
• the length of the first aerosol-forming substrate 212 is such that the first aerosol-forming substrate 212 extends from the distal end of the device cavity 104, through the first region 134 of the first susceptor 122, and to the first intermediate member 128.
• the length of the second aerosol-forming substrate 214 is such that the second aerosol-forming substrate 214 extends from the first intermediate member 128, through the second region 136 of the second susceptor 124, and to the second intermediate member 130.
• the length of the third aerosol-forming substrate 216 is such that the third aerosol-forming substrate 216 extends from the second intermediate member 130 to the proximal end of the device cavity 104.
• a user may draw on the proximal end of the aerosol-generating article 200 to inhale aerosol generated by the aerosol-generating system.
• a user draws on the proximal end of the aerosol generating article 200, air is drawn into the device housing 102 at the air inlet 180, and is drawn along the airflow pathway 181 , into the device cavity 104.
• the air is drawn into the aerosol generating article 200 at the proximal end of the first aerosol-forming substrate 212 through the outlet in the distal end of the device cavity 104.
• This sequence results in heating of the first aerosol forming substrate 212 on a first puff, heating of the second aerosol-forming substrate 214 on a second puff, and heating of the third aerosol-forming substrate 216 on a third puff. Since the aerosol forming substrates 212, 214, 216 of the article 100 are all different, this sequence results in a different experience for a user on each puff on the aerosol-generating system. It will be appreciated that the controller 108 may be configured to supply power to the inductor coils in a different sequence, or simultaneously, depending on the desired delivery of aerosol to the user. In some embodiments, the aerosol-generating device may be controllable by the user to change the sequence.
• FIG 8 shows a schematic illustration of a susceptor arrangement 310 according to an embodiment of this disclosure.
• the susceptor arrangement 310 is an elongate, tubular element, having a circular transverse cross-section.
• the susceptor arrangement 310 comprises a single elongate susceptor, having a first portion 312 and a second portion 314.
• the first portion 312 and the second portion 314 are each elongate, tubular elements having a circular transverse cross- section.
• the first portion 312 and the second portion 314 are coaxially aligned, end-to-end, along a longitudinal axis A-A.
• the cavity 320 comprises two portions, a first portion 322 at a first end, defined by an inner surface of the first portion 312 of the susceptor arrangement 310, and a second portion 324 at a second end, opposite the first end, defined by an inner surface of the second portion 314 of the susceptor arrangement 310.
• the first portion 312 of the susceptor arrangement 310 is arranged to heat a first portion of an aerosol-generating article received in the first portion 322 of the cavity 320
• the second portion 314 of the susceptor arrangement 310 is arranged to heat a second portion of an aerosol-generating article received in the second portion 324 of the cavity 320.
• Such a varying magnetic field generated by the first inductor coil 332 induces eddy currents in the first portion 312 of the susceptor arrangement 310, causing the first portion 312 of the susceptor arrangement 310 to be heated.
• a second inductor coil 334 is disposed around the second portion 314 of the susceptor arrangement 310, and extends substantially the length of the second portion 314 of the susceptor arrangement 310. As such, the second portion 314 of the susceptor arrangement 310 is circumscribed by the second inductor coil 334 of the susceptor arrangement 310 substantially along its length.
• the first portion 312 of the susceptor arrangement 310 and the second portion 314 of the susceptor arrangement 310 may be heated simultaneously by simultaneously supplying a varying electric current, preferably an AC current, to the first inductor coil 332 and the second inductor coil 334.
• the first portion 312 of the susceptor arrangement 310 and the second portion 314 of the susceptor arrangement 310 may be heated independently or alternately by supplying a varying electric current, preferably an AC current, to the first inductor coil 332 without supplying a current to the second inductor coil 334, and by subsequently supplying a varying electric current, preferably an AC current, to the second inductor coil 334 without supplying a current to the first inductor coil 332.
• a varying electric current preferably an AC current
• Temperature sensors in the form of thermocouples, are also provided on outer surfaces of the susceptor arrangement 310.
• a first thermocouple 342 is provided on an outer surface of the first portion 312 of the susceptor arrangement 310 to sense the temperature of the first portion 312 of the susceptor arrangement 310.
• a second thermocouple 344 is provided on an outer surface of the second portion 314 of the susceptor arrangement 310 to sense the temperature of the second portion 314 of the susceptor arrangement 310.
• FIG 9 shows a cross-sectional view of an aerosol-generating system 600 according to another embodiment of the present disclosure.
• the aerosol-generating system 600 comprises an aerosol-generating device 602 comprising the susceptor arrangement 310, the first inductor coil 332 and the second inductor coil 334 of Figure 8.
• the aerosol-generating device 602 is similar to the aerosol-generating device 100 of Figure 5 and like reference numerals are used to designate like parts.
• the aerosol-generating system 600 also comprises an aerosol-generating article 700.
• the aerosol-generating article 700 comprises an aerosol-forming substrate 702 in the form of a cylindrical rod and comprising tobacco strands made from homogenised tobacco and an aerosol former.
• the cylindrical rod of aerosol-forming substrate 702 has a length substantially equal to the length of the device cavity 104.
• the aerosol-generating article 700 also comprises a tubular cooling segment 704, a filter segment 706, and a mouth end segment 708.
• the aerosol-forming substrate 702, the tubular cooling segment 704, the filter segment 706 and the mouth end segment 708 are held together by an outer wrapper 710.
• the aerosol-forming substrate 702 is between 34 millimetres and 50 millimetres in length, more preferably, the aerosol-forming substrate 702 is between 38 millimetres and 46 millimetres in length, more preferably still, the aerosol-forming substrate 702 is 42 millimetres in length.
• the total length of the article 700 is between 71 millimetres and 95 millimetres, more preferably, the total length of the article 700 is between 79 millimetres and 87 millimetres, more preferably still, the total length of the article 700 is 83 millimetres.
• the cooling segment 704 is an annular tube and defines an air gap within the cooling segment 704.
• the air gap provides a chamber for heated volatilised components generated from the aerosol-forming substrate 702 to flow.
• the cooling segment 704 is hollow to provide a chamber for aerosol accumulation yet rigid enough to withstand axial compressive forces and bending moments that might arise during manufacture and whilst the article 700 is in use during insertion into the aerosol-generating device 602.
• the thickness of the wall of the cooling segment 704 is approximately 0.29 millimetres.
• the length of the cooling segment 704 is at least 15 millimetres. In one example, the length of the cooling segment 704 is between 20 millimetres and 30 millimetres, more particularly 23 millimetres to 27 millimetres, more particularly 25 millimetres to 27 millimetres and more particularly 25 millimetres.
• the cooling segment 704 is made of paper.
• the cooling segment 704 is manufactured from a spirally wound paper tube which provides a hollow internal chamber yet maintains mechanical rigidity. Spirally wound paper tubes are able to meet the tight dimensional accuracy requirements of high-speed manufacturing processes with respect to tube length, outer diameter, roundness and straightness.
• the cooling segment 704 is a recess created from stiff plug wrap or tipping paper. The stiff plug wrap or tipping paper is manufactured to have a rigidity that is sufficient to withstand the axial compressive forces and bending moments that might arise during manufacture and whilst the article 700 is in use during insertion into the aerosol-generating device 602.
• the filter segment 706 may be formed of any filter material sufficient to remove one or more volatilised compounds from heated volatilised components from the aerosol-forming substrate 702.
• the filter segment 706 is made of a mono-acetate material, such as cellulose acetate.
• the filter segment 706 provides cooling and irritation-reduction from the heated volatilised components without depleting the quantity of the heated volatilised components to an unsatisfactory level for a user.
• the density of the cellulose acetate tow material of the filter segment 706 controls the pressure drop across the filter segment 706, which in turn controls the draw resistance of the article 700. Therefore the selection of the material of the filter segment 706 is important in controlling the resistance to draw of the article 700. In addition, the filter segment performs a filtration function in the article 700.
• the presence of the filter segment 706 provides an insulating effect by providing further cooling to the heated volatilised components that exit the cooling segment 704. This further cooling effect reduces the contact temperature of the user's lips on the surface of the filter segment 706.
• One or more flavours may be added to the filter segment 706 in the form of either direct injection of flavoured liquids into the filter segment 706 or by embedding or arranging one or more flavoured breakable capsules or other flavour carriers within the cellulose acetate tow of the filter segment 706.
• the filter segment 706 is between 6 millimetres to 10 millimetres in length, more preferably 8 millimetres.
• the mouth end segment 708 is an annular tube and defines an air gap within the mouth end segment 708.
• the air gap provides a chamber for heated volatilised components that flow from the filter segment 706.
• the mouth end segment 708 is hollow to provide a chamber for aerosol accumulation yet rigid enough to withstand axial compressive forces and bending moments that might arise during manufacture and whilst the article is in use during insertion into the aerosol-generating device 602.
• the thickness of the wall of the mouth end segment 708 is approximately 0.29 millimetres.
• the length of the mouth end segment 708 is between 6 millimetres to 10 millimetres and more preferably 8 millimetres.
• the mouth end segment 708 may be manufactured from a spirally wound paper tube which provides a hollow internal chamber yet maintains critical mechanical rigidity. Spirally wound paper tubes are able to meet the tight dimensional accuracy requirements of high-speed manufacturing processes with respect to tube length, outer diameter, roundness and straightness.
• the mouth end segment 708 provides the function of preventing any liquid condensate that accumulates at the exit of the filter segment 706 from coming into direct contact with a user.
• the mouth end segment 708 and the cooling segment 704 may be formed of a single tube and the filter segment 706 is located within that tube separating the mouth end segment 708 and the cooling segment 704.
• Ventilation holes 707 are located in the cooling segment 704 to aid with the cooling of the article 700.
• the ventilation holes 707 comprise one or more rows of holes, and preferably, each row of holes is arranged circumferentially around the article 700 in a cross- section that is substantially perpendicular to a longitudinal axis of the article 700.
• each row of ventilation holes 707 may have between 12 to 36 ventilation holes 707.
• the ventilation holes 707 may, for example, be between 100 to 500 micrometres in diameter.
• an axial separation between rows of ventilation holes 707 is between 0.25 millimetres and 0.75 millimetres, more preferably, an axial separation between rows of ventilation holes 707 is 0.5 millimetres.
• the rows of ventilation holes 707 are located at least 11 millimetres from the proximal end of the article 700, more preferably the ventilation holes 707 are located between 17 millimetres and 20 millimetres from the proximal end of the article 700.
• the location of the ventilation holes 707 is positioned such that user does not block the ventilation holes 707 when the article 700 is in use.
• providing the rows of ventilation holes 707 between 17 millimetres and 20 millimetres from the proximal end of the article 700 enables the ventilation holes 707 to be located outside of the aerosol-generating device 602 when the article 700 is fully inserted in the aerosol-generating device 602.
• By locating the ventilation holes 707 outside of the device 602 non-heated air is able to enter the article 700 through the ventilation holes 707 from outside the device 602 to aid with the cooling of the article 700.
• Figure 10 shows a graph of temperature 404 as a function of time 402 during one heating cycle for the first portion 312 of the susceptor arrangement 310, using readings from the first thermocouple 342, and the second portion of the susceptor arrangement 310, using readings from the second thermocouple 344.
• the temperature of the first portion 312 of the susceptor arrangement 310, from the first thermocouple 342 is shown by the solid line 406.
• the temperature of the second portion 314 of the susceptor arrangement 310, from the second thermocouple 344 is shown by the dashed line 408.
• the first portion 312 of the susceptor arrangement 310 when heating is started, the first portion 312 of the susceptor arrangement 310 is heated quickly during a first phase 410, and reaches an operating temperature after a first period 414 of about 60 seconds.
• the second portion 314 of the susceptor arrangement 310 is heated during the first phase 410, but at a much slower rate than the first portion 312.
• the temperature of the first portion 312 of the susceptor arrangement 310 is greater than the temperature of the second portion 314 of the susceptor arrangement 310 throughout the first phase 410.
• the second portion 314 of the susceptor arrangement 310 does not reach an operating temperature during the first phase 410.
• the operating temperature refers to the desired temperature at which the most desirable aerosol is released from the aerosol forming substrate.
• the first phase 410 ends, and a second phase 412 begins.
• the first portion 312 of the susceptor arrangement 312 is heated to a lower temperature, but still within about 50 degrees Celsius of the operating temperature.
• the second portion 314 of the susceptor arrangement 310 is heated quickly to the operating temperature, and reaches the operating temperature after a third period 418, of about 210 seconds from the start of heating.
• Figure 10 shows a desirable temperature profile for an aerosol-generating system, wherein the first portion 312 of the susceptor arrangement 310 is arranged to heat a proximal portion of an aerosol-forming substrate, and the second portion 314 of the susceptor arrangement 310 is arranged to heat a distal portion of an aerosol-forming substrate.
• the proximal portion of the aerosol-forming substrate is closer to a mouthpiece end of an aerosol generating article comprising the aerosol-forming substrate.
• Heating a proximal portion of an aerosol-forming substrate before heating a distal portion of the substrate facilitates optimum delivery of the generated aerosol to a user.
• this is because the hot aerosol from the heated proximal portion of the aerosol-forming substrate does not interact with the non-heated distal portion of the aerosol-forming substrate during the first phase, and as such, the hot aerosol from the proximal portion does not release volatile compounds from the distal portion.
• Such a temperature profile can be achieved by driving varying currents, preferably AC currents, in the first inductor coil 312 and the second inductor coil 314 in a variety of ways.
• a first varying current preferably an AC current
• a second varying current preferably an AC current
• the duty cycle of the second varying current being less than the duty cycle of the first varying current, such that the current driven in the first inductor coil 312 is greater than the current driven in the second inductor coil 314 during the first phase.
• an inductive heating arrangement 501 is depicted.
• the inductive heating arrangement 501 comprises a first LC circuit 510.
• the first LC circuit 510 comprises a first inductor coil 512 and a first capacitor 514.
• the first inductor coil 512 has a first inductance.
• the first capacitor 514 has a first capacitance.
• the resonance frequency of the first LC circuit 510 is determined by the first inductance and the first capacitance.
• Figure 1 1 further shows a first transistor 516, such as a FET, connected to the first LC circuit 510. Furthermore, terminals 518 of a DC power supply are depicted in figure 11. The terminals 518 of the DC power supply are connected with the power supply, preferably a battery, of the device.
• the first LC circuit 510 is configured to inductively heat a first portion of a susceptor arrangement. The first portion of the susceptor arrangement may be arranged adjacent to the first inductor coil so that the first inductor coil may heat the first portion of the susceptor element by one or both of eddy currents and hysteresis.
• the inductive heating arrangement 501 of figure 11 also comprises a second LC circuit 520 comprising a second inductor coil 522 a second capacitor 524.
• a second transistor 526 is associated with the second LC circuit 520.
• the first transistor 516 is configured for controlling operation of the first LC circuit 510.
• the second transistor 526 is configured for controlling operation of the second LC circuit 520.
• the components of the second LC circuit 520 may be similar to the components of the first LC circuit 510.
• the second inductor coil 522 may have a second inductance
• the second capacitor 524 may have a second capacitance
• the second transistor 526 may be an FET.
• the two LC circuits 510, 520 may be connected to the DC power supply in parallel.
• Figure 12 shows a controller 527 in addition to a power stage 528.
• the power stage 528 may comprise the first LC circuit 510 and the first transistor 516 as depicted in figure 11.
• the power stage 528 may alternatively all of the components depicted in figure 11.
• the controller 527 depicted in figure 12 may comprise an oscillator 530.
• the oscillator 530 may be connected to one or both of the first transistor 516 and the second transistor 526.
• a DC power supply 532 is also shown in figure 12.
• the DC power supply 532 may be utilized for powering the elements shown in figure 11. Additionally, the DC power supply 532 may be utilized to power the controller 527, preferably the oscillator 530.
• the controller 527 may further comprise a pulse width modulation module 534.
• the pulse width modulation module 534 may be configured to modulate the signal used for driving the LC circuits 510, 520.
• the controller 527 may be configured to drive the LC circuits 510, 520. In other words, the controller 527 may be configured to supply an electric signal to the LC circuits 510, 520.
• the pulse width modulation module 534 is optional.
• the controller 527 may be configured to drive the first LC circuit 510 with an AC current of a first frequency.
• the first frequency may correspond to the resonance frequency of the first LC circuit 510.
• the controller 527 may be configured to drive a second LC circuit 520 with an AC current of a second frequency.
• the second frequency may correspond to the resonance frequency of the second LC circuit 520.
• the resonance frequency of the first LC circuit 510 is different from the resonance frequency of the second LC circuit 520.
• the controller 527 may be configured to supply an AC current to the first LC circuit 510 with a frequency corresponding to the resonance frequency of the first LC circuit 510.
• An AC current with the same frequency may be supplied to the second LC circuit 520. Due to the resonance frequency of the second LC circuit 520 being different from the resonance frequency of the first LC circuit 510, the second LC circuit 520 may only heat the second portion of the susceptor arrangement to a lower temperature than the first LC circuit 510 heating first portion of the susceptor arrangement.
• the controller 527 may be configured to supply an AC current with a frequency corresponding to the resonance frequency of the second LC circuit 520, while this AC current will lead to a lower heating of the first portion of the susceptor arrangement by the first LC circuit 510.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
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• Power Engineering (AREA)
• Resistance Heating (AREA)
• General Induction Heating (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Constitution Of High-Frequency Heating (AREA)

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