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EP-3066942-B2 - HEATED AEROSOL-GENERATING DEVICE AND METHOD FOR GENERATING AEROSOL WITH CONSISTENT PROPERTIES

EP3066942B2EP 3066942 B2EP3066942 B2EP 3066942B2EP-3066942-B2

Inventors

  • KUCZAJ, Arkadiusz

Dates

Publication Date
20260513
Application Date
20131217

Claims (19)

  1. A method of controlling aerosol production in an aerosol-generating device, the device comprising: a heater comprising at least one heating element (14) configured to heat a solid aerosol-forming substrate (12); and a power source (16) for providing power to the heating element, comprising the steps of: controlling the power provided to the heating element to heat the solid aerosol-forming substrate such that in a first phase, power is provided to the at least one heating element such that the temperature of the heating element increases from an initial temperature to a first temperature, in a second phase power is provided such that the temperature of the heating element decreases to a second temperature lower than the first temperature and in a third phase power is provided such that the temperature of the heating element increases to a third temperature greater than the second temperature, wherein power is continually supplied during the first, second and third phase, wherein aerosol is generated continuously during the first, second and third phases, wherein: the first phase, second phase and third phase each have a predetermined duration, or the first phase is ended when the heating element reaches the first temperature.
  2. A method of controlling aerosol production according to claim 1, wherein the step of controlling the power provided to the heating element (14) is performed so as to maintain the temperature of the heating element within a desired temperature range in the second phase and in the third phase.
  3. A method of controlling aerosol production according to claim 1, wherein the desired temperature range has a lower bound of between 240 and 340 degrees centigrade and an upper bound of between 340 and 400 degrees centigrade.
  4. A method of controlling aerosol production according to any preceding claim, wherein the first temperature is between 340 and 400 degrees centigrade.
  5. A method according to any preceding claim, wherein the duration of the second phase is determined based on a total amount of power provided to heating element (14) during the second phase.
  6. A method according to any preceding claim, further comprising detecting user puffs on the aerosol-generating device and wherein the first, second or third phase is ended following detection of a predetermined number of user puffs.
  7. A method according to any preceding claim further comprising the step of identifying a characteristic of the aerosol-forming substrate and wherein the step of controlling the power is adjusted dependent on the identified characteristic.
  8. A method according to any preceding claim, wherein the substrate is heated to generate aerosol over a sustained period of more than five seconds.
  9. A method according to any preceding claim, wherein the aerosol-forming substrate is contained in a smoking article that is partially contained within the aerosol-generating device.
  10. A method according to any preceding claim, wherein the step of controlling power is performed to continuously increase the temperature of the heating element during the third phase.
  11. An electrically operated aerosol-generating device, the device comprising: at least one heating element (14) configured to heat a solid aerosol-forming substrate (12) to generate an aerosol; a power supply (16) for supplying power to the heating element; and electric circuitry (18) for controlling supply of power from the power supply to the at least one heating element, wherein the electric circuitry is arranged to: control the power provided to the heating element such that in a first phase, the temperature of the heating element increases from an initial temperature to a first temperature, in a second phase the temperature of the heating element decreases to a second temperature lower than the first temperature and in a third phase the temperature of the heating element increases to a third temperature greater than the second temperature, wherein power is supplied to the heating element during the first, second and third phase, and wherein the electric circuitry is arranged to control the power provided to the heating element such that aerosol is generated continuously during the first, second and third phases, wherein power is continually supplied during the first, second and third phase, wherein: the first phase, second phase and third phase each have a fixed duration, or the first phase is ended when the heating element reaches the first temperature.
  12. An electrically operated aerosol-generating device according to claim 11, further comprising means for detecting user puffs on the aerosol-generating device, wherein the electric circuitry (18) is configured such that at least one of the first, second or third phase is ended following detection of a predetermined number of user puffs.
  13. An electrically operated aerosol-generating device according to claim 11 or 12, further comprising a means for identifying a characteristic of an aerosol-forming substrate in the device and wherein the control circuitry (18) includes a memory holding a look-up table of power control instructions and corresponding aerosol-forming substrate characteristics.
  14. An electrically operated aerosol-generating device according to any one of claims 11 to 13, wherein the heating element is positioned within a cavity (22) in the device, and wherein the cavity is configured to receive an aerosol-forming substrate (12) such that in use the heating element (14) is within the aerosol-forming substrate.
  15. An electrically operated aerosol-generating device according to any one of claims 11 to 14, wherein the electric circuitry is arranged to control the power provided to the heating element such that the substrate is heated to generate aerosol over a sustained period of more than five seconds.
  16. An electrically operated aerosol-generating device according to any one of claims 11 to 15, wherein the aerosol-forming substrate is contained in a smoking article that is partially contained within the aerosol-generating device.
  17. An electrically operated aerosol-generating device according to any one of claims 11 to 16, wherein the electric circuitry is arranged to control the power provided to the heating element such that the temperature of the heating element continuously increases during the third phase.
  18. A computer program which, when run on programmable electric circuitry for an electrically operated aerosol-generating device, causes the programmable electric circuitry to perform the method of claim 1.
  19. A computer readable storage medium having stored thereon a computer program according to claim 18.

Description

The present invention relates to an aerosol-generating device and method for generating an aerosol by heating an aerosol-forming substrate. In particular, the invention relates to a device and method for generating an aerosol from an aerosol-forming substrate with consistent and desirable properties over a period of continuous or repeated heating of the aerosol-forming substrate. Aerosol-generating devices that operate by heating an aerosol forming substrate are known in the art and include, for example, heated smoking devices. US-A-2009/0133691 describes a heated smoking device in which a substrate is heated to generate an aerosol during phases of heating. It is desirable for aerosol-generating devices to be able to produce aerosol which is consistent over time. This is particularly the case when the aerosol is for human consumption, as in a heated smoking device. In devices in which an exhaustible substrate is heated continuously or repeatedly over time this can be difficult, as the properties of the aerosol forming substrate can change significantly with continuous or repeated heating, both in relation to the amount and distribution of aerosol-forming constituents remaining in the substrate and in relation to substrate temperature. In particular, a user of a continuous or repeated heating device can experience a fading of flavour, taste, and feel of the aerosol as the substrate is depleted of the aerosol former that coveys nicotine and, in certain cases, flavouring. Thus, a consistent aerosol delivery is provided over time such that the first delivered aerosol is substantially comparable to a final delivered aerosol during operation. It is an object of the present disclosure to provide an aerosol-generating device and system that provides an aerosol that is more consistent in its properties over a period of continuous or repeated heating of an aerosol-forming substrate. The invention is defined in the appended independent claims. Advantageous features are set out in the dependent claims. As used herein, an 'aerosol-generating device' relates to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, for example part of a smoking article. An aerosol-generating device may be a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhalable into a user's lungs thorough the user's mouth. An aerosol-generating device may be a holder. As used herein, the term 'aerosol-forming substrate' relates to a substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article. As used herein, the terms 'aerosol-generating article' and 'smoking article' refer to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, an aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user's lungs through the user's mouth. An aerosol-generating article may be disposable. The term 'smoking article' is generally used hereafter. A smoking article may be, or may comprise, a tobacco stick. Existing aerosol-generating devices that generate aerosol by heating a substrate repeatedly or continuously are typically controlled to achieve a single constant temperature over time. However, with heating, the aerosol-forming substrate becomes depleted, i.e. the amount of key aerosol constituents in the substrate is reduced, which means reduced aerosol generation for a given temperature. Furthermore, as the temperature in the aerosol-forming substrate reaches a steady state, aerosol delivery is reduced because thermodiffusion effects are reduced. As a result, delivery of aerosol, measured in terms of key aerosol constituents, such as nicotine in the case of heated smoking devices, is reduced over time. Increasing the temperature of the heating element during a final phase of the heating process reduces or prevents the reduction in aerosol delivery over time. In this context, continuous or repeated heating means that the substrate or a portion of the substrate is heated to generate aerosol over a sustained period, typically more than 5 seconds and may extend to more than 30 seconds. In the context of a heated smoking device, or other device on which a user puffs to withdraw aerosol from the device, this means heating the substrate over a period containing a plurality of user puffs, so that aerosol is continuously generated, independent of whether a user is puffing on the device or not. It is in this context that depletion of the substrate becomes a significant issue. This is in contrast to flash heating, in which a separate substrate or por