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EP-4064789-B1 - TEMPERATURE DETERMINATION

EP4064789B1EP 4064789 B1EP4064789 B1EP 4064789B1EP-4064789-B1

Inventors

  • ABI AOUN, WALID
  • FALLON, GARY
  • WHITE, JULIAN DARRYN
  • HORROD, Martin Daniel

Dates

Publication Date
20260506
Application Date
20180327

Claims (14)

  1. An aerosol generating device (150) comprising: an RLC resonance circuit (100) arranged to inductively heat a susceptor (116) inserted, in use, into the aerosol generating device or a susceptor integrated into the aerosol generating device; and an apparatus (114), the device being characterised in that the apparatus (114) is arranged to: measure or determine a frequency characteristic relating to a Q factor of the RLC resonance circuit (100); and determine, based on the measured or determined frequency characteristic, the temperature of the susceptor (116).
  2. The aerosol generating device (150) according to claim 1, further comprising determining a resonant frequency of the RLC resonance circuit (100) based on the frequency characteristic; and/or determining a bandwidth of the RLC resonance circuit (100) based on the frequency characteristic.
  3. The aerosol generating device (150) according to claim 1 or 2, wherein the apparatus is arranged to: determine data indicative of the temperature as a function of the frequency characteristic; and wherein the temperature is determined based on the determined data and the measured or determined frequency characteristic; and optionally: wherein the data comprises one or more parameters of a functional form describing the temperature as a function of the frequency characteristic; and/or wherein the data is a constant of proportionality between the temperature and the frequency characteristic.
  4. The aerosol generating device (150) according to claim 3, wherein the data comprises a series of data points of the temperature measured as a function of the frequency characteristic.
  5. The aerosol generating device (150) according to claim 2, wherein the apparatus (114) is arranged to: determine, based on the measured or determined frequency characteristic, a resistance of the RLC circuit (100); and wherein the determination of the temperature is based on the determined resistance of the RLC circuit (100); and optionally: wherein the apparatus (114) is arranged to: determine a temperature-resistance constant of the susceptor (116); and wherein the determination of the temperature is based on the determined resistance and the determined temperature-resistance constant.
  6. The aerosol generating device (150) according to any one of the preceding claims, wherein the apparatus (114) is arranged to: determine a reference characteristic indicative of the frequency characteristic at a reference temperature; compare the measured or determined frequency characteristic to the determined reference characteristic; and wherein the determination of the temperature is based on the comparison of the measured or determined frequency characteristic to the reference characteristic; and optionally: wherein the apparatus (114) is arranged to: measure the reference characteristic substantially on start-up of the aerosol generating device (150) and/or substantially on installation of a new and/or replacement susceptor (116) into the aerosol generating device (150) and/or substantially on installation of a new and/or replacement inductor (108) into the aerosol generating device (150).
  7. The aerosol generating device (150) according to any preceding claim, wherein the apparatus (114) is arranged to: measure an electrical property of the RLC circuit (100) as a function of a driving frequency at which the RLC circuit is driven; and wherein the measurement or determination of the frequency characteristic is based on the measured electrical property of the RLC circuit (100) as a function of a driving frequency at which the RLC circuit (100) is driven.
  8. The aerosol generating device (150) according to claim 7, wherein the electrical property is a voltage measured across an inductor (108) of the RLC circuit (100), the inductor (108) being for energy transfer to the susceptor (116).
  9. The aerosol generating device (150) according to claim 7, wherein the measurement of the electrical property is a passive measurement; optionally: wherein the electrical property is indicative of a current induced into a sense coil (120a) by an inductor (108) of the RLC circuit (100), the inductor (108) being for energy transfer to the susceptor (116); and/or wherein the electrical property is indicative of a current induced in a pick-up coil (120b) by a supply voltage element (110), the supply voltage element being for supplying voltage to a driving element (102), the driving element being for driving the RLC circuit (100).
  10. The aerosol generating device (150) according to claim 2, wherein the susceptor (116) comprises nickel; and optionally: wherein the susceptor (116) comprises a body having a nickel coating, optionally having a thickness less than substantially 5µm, or substantially in the range 2µm to 3µm and/or wherein the nickel coating is electroplated on to the body.
  11. The aerosol generating device (150) according to claim 2, wherein the susceptor (116) comprises one or more of steel, iron and cobalt, optionally wherein the susceptor (116) is a sheet of mild steel; and optionally wherein the sheet of mild steel has a thickness in the range of substantially 10 µm to substantially 50µm, or has a thickness of substantially 25µm.
  12. A method of determining a temperature of a susceptor (116) inserted, in use, into an aerosol generating device (150) or a susceptor integrated into an aerosol generating device (150), the susceptor being for inductive heating by a RLC resonance circuit (100), the method being characterised by the steps of: measuring or determining a frequency characteristic relating to a Q factor of the RLC resonance circuit (100); and determining, based on the measured or determined frequency characteristic, the temperature of the susceptor (116).
  13. The aerosol generating device (150) or method of any preceding claim, wherein the frequency characteristic comprises the Q factor of the RLC resonance circuit (100).
  14. A computer program which, when executed by a processing system, causes the processing system to perform the method of claim 12 or 13.

Description

Technical Field The present invention relates to apparatus and methods for determining a temperature of a susceptor of an aerosol generating device, more particularly of a susceptor for inductive heating by a RLC resonance circuit. Background Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these articles by creating products that release compounds without combusting. Examples of such products are so-called "heat not burn" products or tobacco heating devices or products, which release compounds by heating, but not burning, material. The material may be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine. EP 2967156 A1 discloses an aerosol-delivery system comprising an inductive heating device. Summary According to a first aspect of the present invention, there is provided an aerosol generating device as defined by claim 1. The frequency characteristic may be a resonant frequency of the RLC resonance circuit. The frequency characteristic may be indicative of a bandwidth of the peak of the frequency response of the RLC circuit. The apparatus may be arranged to: determine data indicative of the temperature as a function of the frequency characteristic; wherein the temperature is determined based on the determined data and the determined frequency characteristic. The data may comprise one or more parameters of a functional form describing the temperature as a function of the frequency characteristic. The data may be a constant of proportionality between the temperature and the frequency characteristic. The data may comprise a series of data points of the temperature measured as a function of the frequency characteristic. The apparatus may be arranged to: determine, based on the determined frequency characteristic, a resistance of the RLC circuit; wherein the determination of the temperature is based on the determined resistance of the RLC circuit. The apparatus may be arranged to: determine a temperature-resistance constant of the susceptor; wherein the determination of the temperature is based on the determined resistance and the determined temperature-resistance constant. The apparatus may be arranged to: determine a reference characteristic indicative of the frequency characteristic at a reference temperature; compare the determined frequency characteristic to the determined reference characteristic; wherein the determination of the temperature is based on the comparison of the determined frequency characteristic to the reference characteristic. The apparatus may be arranged to: measure the reference characteristic substantially on start-up of the aerosol generating device and/or substantially on installation of a new and/or replacement susceptor into the aerosol generating device and/or substantially on installation of a new and/or replacement inductor into the aerosol generating device. The apparatus may be arranged to: measure an electrical property of the RLC circuit as a function of a driving frequency at which the RLC circuit is driven; wherein the determination of the frequency characteristic is based on the measured electrical property of the RLC circuit as a function of a driving frequency at which the RLC circuit is driven. The electrical property may be a voltage measured across an inductor of the RLC circuit, the inductor being for energy transfer to the susceptor. The measurement of the electrical property may be a passive measurement. The electrical property may be indicative of a current induced into a sense coil by an inductor of the RLC circuit, the inductor being for energy transfer to the susceptor. The electrical property may be indicative of a current induced in a pick-up coil by a supply voltage element, the supply voltage element being for supplying voltage to a driving element, the driving element being for driving the RLC circuit. The susceptor may comprise nickel. The susceptor may comprise a body having a nickel coating. The nickel coating may have a thickness less than substantially 5µm, or substantially in the range 2µm to 3µm. The nickel coating may be electroplated on to the body. The susceptor may comprise one or more of steel, iron and cobalt. The susceptor may be a sheet of mild steel. The sheet of mild steel may have a thickness in the range of substantially 10µm to substantially 50µm, or may have a thickness of substantially 25µm. According to a second aspect of the present invention, there is provided a method of determining a temperature of a susceptor of an aerosol generating device as defined by claim 12. According to a third aspect of the present invention, there is provided a computer program which, when executed by a processing system, causes the processing system to perform the method according to the second aspect. Further features and advantages of the invention will become apparent from the following description of pr