Inductive heating device for heating an aerosol-forming substrate comprising a susceptor

Abstract

An inductive heating device for heating an aerosol-forming substrate including a susceptor includes a device housing having a cavity with an internal surface shaped to accommodate at least a portion of the aerosol-forming substrate, a coil arranged to surround at least a portion of the cavity, an electrical power source, and power supply electronics connected to the electrical power source and to the coil, for supplying an alternating current to the coil. The coil is a single coil having a plurality of connection taps arranged at different locations along the coil length to divide the single coil into a plurality of individual coil segments. The power supply electronics individually supply the alternating current to each individual coil segment.

Claims

1. An inductive heating device for heating an aerosol-forming article comprising a susceptor, the inductive heating device comprising: a device housing comprising a cavity having an internal surface shaped to accommodate at least a portion of the aerosol-forming article; a coil arranged to surround at least a portion of the cavity; an electrical power source; and power supply electronics connected to the electrical power source and to the coil to supply an alternating current to the coil to generate in the portion of the cavity surrounded by the coil an alternating magnetic field suitable to heat the susceptor, wherein the coil is a single coil having a coil length and a plurality of different individual coil segments which are sequentially arranged along the cavity, each of the individual coil segments having two connection taps which are arranged at different locations along the coil length, thereby dividing the single coil into the plurality of different individual coil segments, the connection taps being connected to the power supply electronics, and wherein the power supply electronics are configured to individually supply the alternating current to each individual coil segment of the plurality of different individual coil segments, to generate the alternating magnetic field in the portion of the cavity surrounded by the respective individual coil segment supplied with the alternating current.

2. The inductive heating device of claim 1, wherein the power supply electronics are configured to sequentially supply the alternating current to the individual coil segments in a same sequence the individual coil segments are arranged along the cavity.

3. The inductive heating device of claim 2, wherein the power supply electronics are configured to supply the alternating current to a preceding individual coil segment of the sequence and to thereafter supply the alternating current to a subsequent individual coil segment of the sequence, and wherein the power electronics are further configured to start supplying the alternating current to the subsequent individual coil segment of the sequence while continuing to supply the alternating current to the preceding individual coil segment of the sequence, so that there is an overlapping time interval during which the alternating current is supplied to both the preceding individual coil segment and the subsequent individual coil segment of the sequence.

4. The inductive heating device of claim 1, wherein the plurality of coil segments includes three of the individual coil segments.

5. The inductive heating device of claim 1, wherein all of the connection taps are arranged at different locations along the coil length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous aspects of the invention will become apparent from the following description of embodiments with the aid of the drawings in which:

(2) FIG. 1 shows a first embodiment of an inductive heating device and aerosol delivery system according to the invention without mouthpiece;

(3) FIG. 2 shows a second embodiment of an inductive heating device and system according to the invention with mouthpiece;

(4) FIG. 3 shows a schematic representation of the cavity and the single coil comprising the individual coil segments and an aerosol-forming article comprising susceptor particles, and

(5) FIG. 4 shows a schematic representation of the cavity and the single coil comprising the individual coil segments and an aerosol-forming article comprising susceptor strips.

DETAILED DESCRIPTION

(6) FIG. 1 shows a first embodiment of an inductive heating device 1 according to the invention with an aerosol-forming article 2 arranged in a cavity 11 of the device housing 10 of inductive heating device 1, the inductive heating device 1 and the aerosol-forming article 2 together forming an aerosol delivery system according to the invention. As shown in FIG. 1, the aerosol-forming article 2 may comprise a solid tobacco-laden substrate 20 and a filter portion 21, however, this is by way of example only rather than being mandatory. As can be seen further in FIG. 1, the solid tobacco-laden substrate 20 comprises susceptor particles 22 which are distributed in the tobacco-laden substrate 20 but are depicted in FIG. 1 in the lower half of tobacco-laden substrate 20 only. As mentioned already, the aerosol-forming article 2 may have the shape of a rod, with the internal surface 110 of the cavity 11 being sized and shaped to accommodate the rod of tobacco-laden substrate 20.

(7) A single helically wound inductor coil L is also shown in FIG. 1 which is arranged to surround cavity 10 to be capable of inducing an alternating magnetic field within cavity 10. Inductor coil L comprises a plurality of individual coil segments, with three such individual coil segments L1, L2 and L3 being shown. Each individual coil segment comprises two connection taps, for example coil segment L1 comprises two connection taps L11 and L12, coil segment L2 comprises two connection taps L21 and L22, and coil segment L3 comprises two connection taps L31 and L32. These connection taps L11, L21, L31, L12, L22, L32 are arranged at different locations along the length l of coil L, this being indicated in FIG. 1 only schematically, as the connection taps are of course arranged in the device housing 10, as are the connections between the power supply electronics and the connection taps (as is discussed in more detail below).

(8) Inductive heating device 1 further comprises an electrical power source 12, which may be a DC power source such as a battery (e.g. a rechargeable battery). A docking port 13 comprising a pin 130 for recharging the battery is also indicated in FIG. 1 by way of example.

(9) Inductive heating device 1 further comprises a power supply electronics 14 connected to the electrical power source 12 (rechargeable battery) on one hand and to coil L on the other hand. Power supply electronics 14 is capable of supplying an alternating current to the connection taps of the individual coil segments L1, L2 and L3. This is schematically indicated by the dashed connection lines and switches S11, S21, S31, S12, S22, S32 which are illustrated in FIG. 1 for better understanding only. In practice, the electrical connections are arranged within device housing 10, and since the power supply electronics 14 may typically comprise a microcontroller unit (not shown in detail), the supply of alternating voltage/current to the respective signal outlets of the microcontroller unit can be “switched” within the microcontroller unit and directly supplied to the respective signal outlets of the microcontroller unit which can be directly connected to the respective connection taps L11, L12, L13, L12, L22, L32 of the individual coil segments.

(10) FIG. 2 shows a further embodiment of the inductive heating device 3 according to the invention. However, FIG. 2 only very schematically shows this further embodiment of the inductive heating device according to the invention, as many components that have been described in connection with the embodiment of FIG. 1 can be present in the embodiment of FIG. 2 as well, so that they need not be described in detail again. An essential difference of the embodiment of the inductive heating device 3 of FIG. 2 vis-a-vis the embodiment of the inductive heating device 1 of FIG. 1 is that the embodiment of FIG. 2 comprises a mouthpiece 35 whereas the embodiment of FIG. 1 does not comprise such mouthpiece. Accordingly, inductive heating device 3 comprises a device housing 30 comprising a cavity 31 in which a rod of solid tobacco-laden substrate 40 (here: without filter) of an aerosol-forming article 4 is arranged. The solid tobacco-laden substrate 40 again comprises susceptor particles 42 distributed within the solid tobacco-laden substrate 40, these susceptor particles 42 again being illustrated only in the lower half of the tobacco-laden substrate 42. Coil L is again arranged to surround cavity 31, with the individual coil segments again being indicated by reference signs L1, L2, L3. Again, the internal surface 310 of cavity 31 is sized and shaped to accommodate the rod of tobacco-laden substrate 40 of the aerosol-forming article 4.

(11) FIG. 3 shows in more detail cavity 11 of the embodiment of the inductive heating device 1 shown in FIG. 1, with only the rod of solid tobacco-laden substrate 20 being shown and arranged in cavity 11 of device housing 10, and with coil L surrounding the tobacco-laden substrate 20 containing the susceptor particles 22. Similarly, the following description of FIG. 3 and FIG. 4 also holds for cavity 31 of the embodiment of the inductive heating device 3 shown in FIG. 2. The three coil segments L1, L2, L3 are indicated through the respective groups of arrows representing the individual coil segments L1, L2, L3.

(12) FIG. 4 also shows in more detail cavity 11, with coil L being arranged to surround cavity 11 in which tobacco laden substrate 20 is arranged. However, different from the embodiment shown in FIG. 3, tobacco-laden substrate 20 comprises susceptor strips 23 which are arranged equidistantly spaced along the length of the rod of tobacco-laden substrate 20. The susceptor strips 23 extend in a direction generally transverse to, in the embodiment shown perpendicular to, the length of the rod of tobacco-laden substrate 20.

(13) Operation of the inductive heating device and aerosol delivery system according to the invention is described in the following.

(14) As has been mentioned further above, the various segments L1, L2, L3 of coil L are individually supplied with an alternating current. For the sake of simplicity, let us assume that the individual coil segments L1, L2, L3 are supplied by first supplying coil segment L1, thereafter supplying coil segment L2, and then supplying coil segment L3 with the alternating current. For that purpose, a direct current (DC) drawn from battery 12 is converted into an alternating current (AC) by power supply electronics 14 which may contain a DC/AC inverter for that purpose. The alternating current is then sequentially supplied to the individual coil segments L1 (first), L2 (second), L3 (third). However, any other sequence of supplying the alternating current to the coil segments L1, L2, L3 is considered to be within the scope of the invention as well. Also, as already mentioned further above, the time intervals during which the individual coil segments L1, L2 as well as L2, L3 are supplied with alternating current may overlap, so that for a certain overlapping time interval both coil segments L1 and L2 may be simultaneously supplied with alternating current before supply of alternating current to coil segment L1 is discontinued (and alternating current is supplied to coil segment L2 only). Similarly, for a certain overlapping time interval both coil segments L2 and L3 are supplied with alternating current before the supply of alternating current to coil segment L2 is discontinued (and alternating current is supplied to coil segment L3 only).

(15) By way of example only, in case the entire consuming run has a duration of six minutes, the first individual coil segment L1 of coil L may be supplied with the alternating current for two minutes. After these first two minutes the second individual coil segment L2 of coil L may be supplied with the alternating current for another two minutes (i.e. for the third and fourth minute counted from the start of the consuming run), and thereafter the third individual coil segment L3 is supplied with the alternating current for yet another two minutes (i.e. for the fifth and sixth minute counted from the start of the consuming run). The overlapping time interval (during which two adjacently arranged individual coil segments are both supplied with the alternating current) may have a duration of thirty seconds.

(16) FIG. 1 shows a state in which the alternating current is supplied to coil segment L2 only. As switches S11 and S21 are both closed, the respective connection taps L11, L12 and L21 have the same voltage potential. Consequently, no alternating current flows through coil segment L1. Similarly, switches S22 and S32 are in the closed state, so that the respective connection taps L32, L31 and L22 have the same voltage potential. Consequently, no alternating current flows through coil segment L3, either. The alternating current flows through connection tap L21, through coil segment L2 and through connection tap L22.

(17) As a consequence, an alternating magnetic field is generated by coil segment L2 only, thus heating up portion 201 (see FIG. 3) of the rod of solid tobacco-laden substrate 20 by generating heat in the susceptor particles 22 through hysteresis losses only, or through a combination of hysteresis losses and eddy current losses, depending on the type of material the susceptor particles 22 are made of Through this heating up, an aerosol is generated releasing the flavor which can be inhaled by the consumer through drawing at the filter 21 (or at the mouthpiece 35, respectively).

(18) It is clear, that for heating up portion 200 (see FIG. 3) of the rod of solid tobacco-laden substrate 20 switch S11 is closed while S21 and S31 are both open, and all three switches S12, S22 and S32 are closed, so that the alternating current only flows through coil segment L1 while no current flows through coil segments L2 and L3. Similarly, for heating up portion 202 (see FIG. 3) of the rod of tobacco-laden substrate 20, switches S11, S21 and S31 and S32 are closed while switches S12 and S22 are open, so that the alternating current only flows through coil segment L3 while no current flows through coil segments L1 and L2.

(19) Similar considerations hold for the embodiment of the rod of tobacco-laden substrate 20 comprising the susceptor strips 23 (FIG. 4), and for the embodiment of the inductive heating device shown in FIG. 2 in which the aerosol-forming article 4 comprising the rod of tobacco-laden substrate 40 is arranged within the cavity 31. (embodiment with mouthpiece).

(20) Various embodiments of the inductive heating device, the aerosol-delivery system and the method of operating have been described above with the aid of the embodiments shown in the drawings. However, these embodiments have been described by way of example only, and various changes and modifications are possible without departing from the general teaching underlying the invention. Therefore, the invention is not limited to the embodiments described, but rather the scope of protection is defined by the appended claims.