AEROSOL-FORMING ARTICLE COMPRISING MAGNETIC PARTICLES

Abstract

An aerosol-forming article for use in an electrically heated aerosol-generating device is provided, the aerosol-forming article including a mouthpiece, an aerosol-forming substrate, and a plurality of magnetic particles including a magnetic material having a Curie temperature of between 60 degrees Celsius and 200 degrees Celsius. An electrically heated aerosol-generating device for receiving the aerosol-forming article is also provided, the device including a heater element configured to heat the aerosol-forming article, an inductor, and a controller configured to measure an inductance of the inductor and to control a supply of electrical current to the heater element in response to the measured inductance.

Claims

1.-13. (canceled)

14. An aerosol-forming article for an electrically heated aerosol-generating device, the aerosol-forming article comprising: a mouthpiece; an aerosol-forming substrate; and a plurality of magnetic particles comprising a magnetic material having a Curie temperature of between about 60 degrees Celsius and about 200 degrees Celsius.

15. The aerosol-forming article according to claim 14, wherein the plurality of magnetic particles are disposed within the aerosol-forming substrate.

16. The aerosol-forming article according to claim 14, wherein the plurality of magnetic particles are present in an amount of between about 1 percent by weight and about 30 percent by weight of the aerosol-forming substrate.

17. The aerosol-forming article according to claim 14, wherein an average diameter of the magnetic particles is between about 25 micrometers and about 75 micrometers.

18. An electrically heated aerosol-generating device configured to receive an aerosol-forming article, the device comprising: a heater element configured to heat the aerosol-forming article; an inductor; and a controller configured to repeatedly measure an inductance of the inductor and a temperature of the heater element, the controller being further configured to vary a supply of electrical current to the heater element in response to the measured inductance to provide a predetermined heating profile.

19. The electrically heated aerosol-generating device according to claim 18, wherein both the heater element and the inductor are formed by a conductive coil.

20. The electrically heated aerosol-generating device according to claim 19, wherein the controller is further configured to: pulse the supply of electrical current through the conductive coil to heat the aerosol-forming article, and measure an inductance of the conductive coil between current pulses.

21. An electrically heated aerosol-generating system, comprising an electrically heated aerosol-generating device in combination with an aerosol-forming article, the electrically heated aerosol-generating device comprising: a heater element configured to heat the aerosol-forming article, an inductor, and a controller configured to repeatedly measure an inductance of the inductor and a temperature of the heater element, the controller being further configured to vary a supply of electrical current to the heater element in response to the measured inductance to provide a predetermined heating profile; the aerosol-forming article comprising: a mouthpiece, an aerosol-forming substrate, and a plurality of magnetic particles comprising a magnetic material having a Curie temperature of between about 60 degrees Celsius and about 200 degrees Celsius.

22. A method of operating an electrically heated aerosol-generating system comprising an aerosol-forming article comprising a plurality of magnetic particles, a heater element configured to heat the aerosol-forming article, an inductor, and a controller configured to measure an inductance of the inductor and to control a supply of electrical current to the heater element, the method comprising: measuring the inductance of the inductor; comparing the measured inductance with one or more predetermined values of inductance; controlling the supply of electrical current to the heater element based on the comparison of the measured inductance with the one or more predetermined values of inductance, by activating the supply of current to the heater element to heat the aerosol-forming article to a temperature above a Curie temperature of the plurality of magnetic particles; repeatedly measuring the inductance of the inductor and the temperature of the heater element during the heating of the aerosol-forming article; determining when a decrease in the measured inductance occurs during the heating of the aerosol-forming article, the decrease in the inductance being indicative of the plurality of magnetic particles being heated to the Curie temperature; and varying the electrical current supplied to the heater element to provide a predetermined heating profile, wherein the predetermined heating profile is selected based on at least one of a time at which the decrease in measured inductance occurs and a heater element temperature at which the decrease in measured inductance occurs.

23. The method according to claim 22, wherein the controlling the supply of electrical current to the heater element further comprises supplying no current to the heater element if the measured inductance does not match any of the one or more predetermined values of inductance, and wherein each of the one or more predetermined values of inductance corresponds to a type of aerosol-forming article.

24. The method according to claim 22, wherein the one or more predetermined values of inductance comprises a plurality of predetermined values of inductance, wherein the controlling the supply of electrical current to the heater element further comprises varying the electrical current supplied to the heater element to provide a predetermined heating profile, and wherein the predetermined heating profile is selected based on which of the plurality of predetermined values of inductance matches the measured inductance.

25. The method according to claim 22, wherein the electrically heated aerosol-generating system further comprises a conductive coil that forms both the heater element and the inductor, wherein the activating the supply of electrical current to the heater element to heat the aerosol-forming substrate further comprises pulsing the supply of electrical current through the conductive coil, and wherein the repeatedly measuring the inductance of the inductor further comprises measuring the inductance of the conductive coil between current pulses.

Description

[0045] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0046] FIG. 1 shows an aerosol-forming article in accordance with the present invention; and

[0047] FIG. 2 shows the aerosol-forming article of FIG. 1 inserted into an electrically heated aerosol-generating device in accordance with the present invention.

[0048] FIG. 1 shows an aerosol-forming article 10 comprising an aerosol-forming substrate 12, a hollow acetate tube 14, a polymeric filter 16, a mouthpiece 18 and an outer wrapper 20. The aerosol-forming substrate 12 comprises a plurality of ferromagnetic particles 22 distributed within a plug of tobacco 24. The mouthpiece 18 comprises a plug of cellulose acetate fibres.

[0049] FIG. 2 shows the aerosol-forming article 10 inserted into an electrically heated aerosol-generating device 30. The device 30 includes a heater element 32 comprising a base portion 34 and a heater blade 36 that penetrates the aerosol-forming substrate 12. The heater blade 36 includes a conductive coil 38 configured to receive a supply of electrical current from a battery 40 provided within the device 30. A controller 42 controls the operation of the device 30, including the supply of electrical current from the battery 40 to the conductive coil 38 of the heater blade 36.

[0050] During use, the controller 42 determines that the aerosol-forming article 10 is suitable for use with the device 30 by detecting the change in inductance of the conductive coil 38 as a result of the ferromagnetic particles 22 in the aerosol-forming substrate 12 being positioned proximate the conductive coil 38.

[0051] After determining that the aerosol-forming article 10 can be used with the device 30, the controller 42 begins pulsing the current from the battery 40 through the conductive coil 38 to heat the aerosol-forming substrate 12. Between current pulses, the controller 42 continues to monitor the inductance of the conductive coil 38 to determine the point at which a significant change in inductance occurs. The change in inductance indicates that the ferromagnetic particles 22 have been heated to their Curie temperature. The controller determines the temperature by measuring the resistivity of the conductive coil 38 at the moment when the change in inductance occurs. Based on the Curie temperature, the controller 42 determines the type of aerosol-forming article 10 and selects the appropriate heating profile.