Induction heating assembly for a vapour generating device

Abstract

An induction heating assembly for a vapour generating device includes an induction coil, radially inward of which a heating compartment is defined for receiving, in use, a body including a vaporisable substance and an induction heatable susceptor; and a temperature sensor located against a side of the heating compartment on the central longitudinal axis of the induction coil at an end of the heating compartment, wherein the induction coil is arranged to heat, in use, the susceptor, and the temperature sensor is arrange to monitor, in use, a temperature related to heat generated from the susceptor. There is also provided an induction heatable cartridge for use with the induction heating assembly. The cartridge includes a solid vaporisable substance; and an induction heatable susceptor held by the vaporisable substance, the susceptor being planar and having an outwardly facing edge and an inwardly facing edge.

Claims

1. An induction heating assembly for a vapour generating device, the heating assembly comprising: an induction coil, radially inward of which a heating compartment is defined for receiving, in use, a body comprising a vaporisable substance and an induction heatable susceptor; and a temperature sensor located against a side of the heating compartment on a central longitudinal axis of the induction coil at an end of the heating compartment, wherein the induction coil is arranged to heat, in use, the susceptor, and the temperature sensor is arrange to monitor, in use, a temperature related to heat generated from the susceptor.

2. The heating assembly according to claim 1, wherein the induction coil has a cylindrical shape.

3. The heating assembly according to claim 1, where the temperature sensor is positioned between an axial centre of the induction coil and an axial end of the induction coil.

4. The heating assembly according to claim 3, wherein the temperature sensor is sized and positioned in use so as not to extend closer to the axial centre of the induction coil than a point midway between the axial centre of the induction coil and the axial end of the induction coil proximate to the temperature sensor.

5. An induction heatable cartridge for use with an induction heating assembly, the cartridge comprising: a solid vaporisable substance; and an induction heatable susceptor held by the vaporisable substance, the susceptor being planar and having an outwardly facing edge and an inwardly facing edge, wherein a total length of the inwardly facing edge of the susceptor in a central region of the cartridge with a first area is greater than a total length of the outwardly facing edge of the susceptor in any of a plurality of outer regions of the cartridge, each of the plurality of outer regions having the same shape and orientation as the central region and with an area equal to the first area, wherein the plurality of outer regions extend radially beyond an outer perimeter of the cartridge.

6. The cartridge according to claim 5, wherein the susceptor has an aperture in the central region.

7. The cartridge according to claim 6, wherein the central region has a total length of a combined edge greater than a total length of a combined edge in any of the plurality of outer regions, each combined edge comprising inwardly facing edge portions and outwardly facing edge portions.

8. The cartridge according to claim 5, wherein the susceptor comprises a plurality of plates arranged in substantially parallel planes.

9. The cartridge according to claim 8, wherein each plate takes the form of a part of a disc or a ring, each plate being located with a radial separation between the plate and a mid-point of the central region.

10. An induction heatable cartridge for use with an induction heating assembly, the cartridge comprising: a solid vaporisable substance; and an induction heatable susceptor held by the vaporisable substance, the susceptor comprising one or more susceptor plates being ring shaped so as to provide respective apertures, at least one of which radially surrounds a temperature monitoring region and is located axially between a centre of the cartridge and the temperature monitoring region, whereby a temperature sensor projects into the temperature monitoring region without passing substantially through the aperture of any of the one or more susceptor plates when the cartridge is fitted into a heating compartment of an induction heating assembly, and wherein the cartridge further comprises a deformable portion adjacent the temperature monitoring region for permitting the temperature sensor to project into the temperature monitoring region when fitted into a heating compartment of an induction heating assembly.

11. The cartridge according to claim 5, wherein the vaporisable substance includes tobacco, humectant, glycerine and/or propylene glycol.

12. A vapour generating device comprising: an induction heating assembly comprising: an induction coil, radially inward of which a heating compartment is defined for receiving, in use, a body comprising a vaporisable substance and an induction heatable susceptor; and a temperature sensor located against a side of the heating compartment on a central longitudinal axis of the induction coil at an end of the heating compartment, wherein the induction coil is arranged to heat, in use, the susceptor, and the temperature sensor is arrange to monitor, in use, a temperature related to heat generated from the susceptor; the induction heatable cartridge according to claim 5 located within the heating compartment of the induction heating assembly; an air inlet arranged to provide air to the heating compartment; and an air outlet in communication with the heating compartment.

13. The vapour generating device according to claim 12, wherein the susceptor has an aperture in the central region of the cartridge, the susceptor being orientated and the aperture being sized and located such that the temperature sensor is located within the aperture.

14. The vapour generating device according to claim 12, wherein an outer portion of the susceptor of the cartridge is closer to the induction coil of the induction heating assembly than the temperature sensor of the induction heating assembly is to the induction coil.

15. The vapour generating device according to claim 12, wherein the temperature sensor of the induction heating assembly is positioned between an axial centre of the induction coil of the induction heating assembly and an axial end of the induction coil, a part of the induction heatable cartridge being located in use at the axial centre of the induction coil.

16. The heating assembly according to claim 3, wherein the axial end of the induction coil is a closest axial end to the side of the heating compartment against which the temperature sensor is located.

17. The cartridge according to claim 10, wherein the one or more susceptor plates includes a plurality of plates arranged in substantially parallel planes.

18. The cartridge according to claim 10, wherein the vaporisable substance includes tobacco, humectant, glycerine and/or propylene glycol.

19. A vapour generating device comprising: an induction heating assembly comprising: an induction coil, radially inward of which a heating compartment is defined for receiving, in use, a body comprising a vaporisable substance and an induction heatable susceptor; and a temperature sensor located against a side of the heating compartment on a central longitudinal axis of the induction coil at an end of the heating compartment, wherein the induction coil is arranged to heat, in use, the susceptor, and the temperature sensor is arrange to monitor, in use, a temperature related to heat generated from the susceptor; the induction heatable cartridge according to claim 10 located within the heating compartment of the induction heating assembly; an air inlet arranged to provide air to the heating compartment; and an air outlet in communication with the heating compartment.

Description

BRIEF DESCRIPTION OF FIGURES

(1) An example of an induction heating assembly and an example of an induction heatable cartridge are described in detail below, with reference to the accompanying figures, in which:

(2) FIG. 1 shows a schematic view of an example vapour generating device;

(3) FIG. 2 shows an exploded view of the vapour generating device according to the example shown in FIG. 1;

(4) FIG. 3 shows a schematic view of an example induction coil and temperature sensor;

(5) FIG. 4 shows a schematic view of an example induction heatable cartridge, induction coil and temperature sensor;

(6) FIGS. 5A and 5B show cross-sectional plan views of example induction heatable cartridges;

(7) FIGS. 6A, 6B and 6C show a schematic view of example susceptor plates;

(8) FIG. 7 shows an example arrangement of example susceptor plates; and

(9) FIG. 8 shows a further example arrangement of example susceptor plates.

DETAILED DESCRIPTION

(10) We now describe an example of a vapour generating device, including a description of an example induction heating assembly, example induction heatable cartridges and example susceptors.

(11) Referring now to FIG. 1 and FIG. 2, an example vapour generating device is generally illustrated at 1 in an assembled configuration in FIG. 1 and an unassembled configuration in FIG. 2.

(12) The example vapour generating device 1 is a hand held device (by which we intend to mean a device that a user is able to hold and support un-aided in a single hand), which has an induction heating assembly 10, an induction heatable cartridge 20 and a mouthpiece 30. Vapour is released by the cartridge when it is heated. Accordingly, vapour is generated by using the induction heating assembly to heat the induction heatable cartridge. The vapour is then able to be inhaled by a user at the mouthpiece.

(13) In this example, a user inhales the vapour by drawing air into the device 1 from the surrounding environment, through or around the induction heatable cartridge 20 and out of the mouthpiece 30 when the cartridge is heated. This is achieved by the cartridge being located in a heating compartment 12 defined by a portion of the induction heating assembly 10, and the compartment being in gaseous connection with an air inlet 14 formed in the assembly and an air outlet 32 in the mouthpiece when the device is assembled. This allows air to be drawn through the device by application of negative pressure, which is usually created by a user drawing air from the air outlet.

(14) The cartridge 20 is a body which includes a vaporisable substance 22 and an induction heatable susceptor 24. In this example the vaporisable substance includes one or more of tobacco, humectant, glycerine and propylene glycol. The vaporisable substance is also solid (note that liquid components such as propylene glycol and glycerine may be absorbed by an absorbent solid material such as tobacco). The susceptor includes a plurality of plates that are electrically conducting. In this example, the cartridge also has a layer or membrane 26 to contain the vaporisable substance and susceptor, with the layer or membrane being air permeable. In other examples, the membrane is not present.

(15) As noted above, the induction heating assembly 10 is used to heat the cartridge 20. The assembly includes an induction heating device, in the form of an induction coil 16 and a power source 18. The power source and the induction coil are electrically connected such that electrical power may be selectively transmitted between the two components.

(16) In this example, the induction coil 16 is substantially cylindrical such that the form of the induction heating assembly 10 is also substantially cylindrical. The heating compartment 12 is defined radially inward of the induction coil with a base at an axial end of the induction coil and side walls around a radially inner side of the induction coil. The heating compartment is open at an opposing axial end of the induction coil to the base. When the vapour generating device 1 is assembled, the opening is covered by the mouthpiece 30 with an opening to the air outlet 32 being located at the opening of the heating compartment. In the example shown in the figures, the air inlet 14 has an opening into the heating compartment at the base of the heating compartment.

(17) A temperature sensor 11 is located at the base of the heating compartment 12. Accordingly, the temperature sensor is located within the heating compartment at the same axial end of the induction coil 16 as the base of the heating compartment. This means that when a cartridge 20 is located in the heating compartment and when the vapour generating device 1 is assembled (in other words when the vapour generating device is in use or ready for use) the cartridge is deformed around temperature sensor. This is because, in this example, the temperature sensor does not pierce the membrane 26 of the cartridge due to its size and shape.

(18) The temperature sensor 11 is also located on the central longitudinal axis 34 of the induction coil 16. As shown in FIG. 3, the induction coil has axial ends 36, 38. These are the extreme ends of the coil. The induction coil also has an axial centre 40. This is located half way between the axial ends of the induction coil. The central longitudinal axis intersects planes across each of the axial ends and axial centre of the induction coil. In FIG. 3 the temperature sensor is shown located only between one axial end and the axial centre. This is permissible in some examples. FIG. 3 also shows example EM field lines 42 of the EM field producible by the induction coil. These are generally oval in shape having their widest point at about the axial centre of the coil. Due to the position of the temperature sensor relative to the EM field, this allows any interaction with the EM field to be weaker the further from the axial centre the temperature sensor is located.

(19) FIG. 4 shows an enlarged view of how the induction coil 16, cartridge 20 and temperature sensor 11 are arranged relative to each other when the device is assembled. FIG. 4 also shows example EM field lines 44 of the EM field producible by the induction coil. In this example, there are three susceptor plates with each located in a parallel plane, with each plane being perpendicular to the central longitudinal axis of the induction coil. The susceptor plates are located in the middle of the cartridge, and therefore their mid-points are aligned along the central longitudinal axis of the induction coil. The susceptor plates themselves are orientated so they are perpendicular to the central longitudinal axis of the induction coil.

(20) The susceptor plates 24 are wider than the temperature sensor 11. This means that portions of each susceptor plates are closer to the induction coil 16 than the temperature sensor. This causes the susceptor plates to interact more with the EM field when it is generated than the temperature sensor interacts with the EM field.

(21) Returning to FIGS. 1 and 2, the temperature sensor 11 is electrically connected to a controller 13 located within the induction heating assembly 10. The controller is also electrically connected to the induction coil 16 and the power source 18, and is adapted in use to control operation of the induction coil and the temperature sensor by determining when each is to be supplied with power from the power source.

(22) As mentioned above, in order for vapour to be produced, the cartridge 20 is heated. This is achieved by an electrical current being supplied by the power source 18 to the induction coil 16. The current flows through the induction coil causing a controlled EM field to be generated in a region near the coil. The EM field generated provides a source for an external susceptor (in this case the susceptor plates of the cartridge) to absorb the EM energy and convert it to heat, thereby achieving induction heating.

(23) In more detail, by power being provided to the induction coil 16 a current is caused to pass through the induction coil, causing an EM field to be generated. The current supplied to the induction coil is an alternating (AC) current. This causes heat to be generated within the cartridge because, when the cartridge is located in the heating compartment 12, it is intended that the susceptor plates are arranged (substantially) parallel to the radius of the induction coil 16 as is shown in the figures, or at least have a length component parallel to the radius of the induction coil. Accordingly, when the AC current is supplied to the induction coil while the cartridge is located in the heating compartment, the positioning of the susceptor plates causes eddy currents to be induced in each plate due to coupling of the EM field generated by the induction coil to each susceptor plate. This causes heat to be generated in each plate by induction.

(24) The plates of the cartridge 20 are in thermal communication with the vaporisable substance 22, in this example by direct or indirect contact between each susceptor plate and the vaporisable substance. This means that when the susceptor 24 is inductively heated by the induction coil 16 of the induction heating assembly 10, heat is transferred from the susceptor 24 to the vaporisable substance 22, to heat the vaporisable substance 22 and produce a vapour.

(25) When the temperature sensor 11 is in use, it monitors the temperature by measuring temperature at its surface. Each temperature measurement is sent to the controller 13 in the form of an electrical signal.

(26) The cartridge 20 has a number of possible configurations. Some example configurations are shown in the remaining figures. Referring now to FIGS. 5A and 5B, these show two example cartridges.

(27) FIG. 5A shows a cartridge 20 that has a circular cross-section perpendicular to its length. The cartridge has vaporisable material 22 that surrounds a circular susceptor plate 24. FIG. 5A shows one circular susceptor plate of the cartridge. The mid-point of the susceptor plate is aligned with the mid-point of the cartridge. The susceptor plate has a circular aperture 46 at its centre. This means that as well as having an outwardly facing edge 48 around the circumference (i.e. outer perimeter) of the susceptor plate, the susceptor plate also has an inwardly facing edge 50 around the perimeter of the aperture.

(28) A grid 52 is shown in FIG. 5A (and in FIG. 5B). The grid consists of nine equally sized squares arranged in a three by three array. The array is sized so that the outer sides of the array form tangents to the outside edge of the cartridge 20 shown in FIG. 5A. The sides of the square in the middle of the array (i.e. in the middle square in the middle row and middle column) also form tangents to the perimeter of the aperture 46 in the susceptor plate 24. This central region therefore includes the inwardly facing edge 50 of the susceptor plate. The length of inwardly facing edge in this region is greater than the length of outwardly facing edge in any of the outer regions provided by the other eight squares of the array. This means that when the susceptor plate is coupled to an EM field, most heat will be generated in the central region.

(29) FIG. 5B shows a similar cartridge 20 to the cartridge shown in FIG. 5A. The only difference is that the cartridge has a pentagonal cross-section instead of a circular cross-section. In this example, the grid 52 is still the same size and shape as the grid shown in FIG. 5A. As such, the sides of the grid form tangents to a circle (not shown) joining the vertices of the pentagon.

(30) FIGS. 6A, 6B and 6C show an example configuration of the susceptor plates 24. As mentioned above, the susceptor plates are arranged in three planes. FIGS. 6A, 6B and 6C each show one of these planes. Each susceptor plate has two portions 24A, 24B. The portions are identically shaped segments of a circle. The portions are separated, and the gap between the portions is in the region in which the rest of the circle of which the portions are segments would be located if present. The portions each have an outwardly facing edge, which is the curved edge that provides an arc from a circumference of a circle. Each portion also has an inwardly facing edge. The inwardly facing edges are straight and make up the remainder of the perimeter of each portion.

(31) FIGS. 6A to 6C show the same grid as FIGS. 5A and 5B. On this grid, the inwardly facing edges of the portions 24A, 24B of the susceptor plate 24 are separated by the width of one square. In FIG. 6A, this means that the inwardly facing edges of the portions are located on opposing sides of the middle column of the three by three array. Accordingly, the middle square of the array has the greatest length of inwardly facing edge in it, and that length is greater than the length of outwardly facing edge in any directly comparable outer region.

(32) FIGS. 6B and 6C show identical susceptor plates 24 to the susceptor plate shown in FIG. 6A. The only difference is that the plate has been rotated about the mid-point of the respective susceptor plate relative to the orientation of the susceptor plate shown in FIG. 6A. The susceptor plate shown in FIG. 6B has been rotated about 45 degrees (°) clockwise, and the susceptor plate shown in FIG. 6C has been rotated about 135° clockwise from the orientation of the susceptor plate shown in FIG. 6A. The grid is not rotated, but the middle square retains a greater length of inwardly facing edge than any other square and also a greater length of inwardly facing edge than the total length of outwardly facing edge contained in any square.

(33) As set out above FIGS. 6A to 6C show susceptor plates 24 that are located in parallel planes spread along the central longitudinal axis of the induction coil 11 when the cartridge is assembled. FIG. 7 shows the susceptor plates in the configuration shown in FIGS. 6A to 6C separated as in FIGS. 6A to 6C and a plan view of those susceptor plates positioned as they are in a cartridge when they are ready to use. When assembled, the susceptor plates of this arrangement encircle the temperature sensor 11 when the cartridge is located in the heating compartment. Accordingly, an aperture is provided through the susceptor plates maintaining a lateral separation between the susceptor plates and the temperature sensor while providing a susceptor around a full circle over different levels.

(34) A further configuration that achieves this is shown in FIG. 8. FIG. 8 shows four portions 24A, 24B, 24C, 24D of a susceptor 24. As with the portions of susceptor plate shown in FIGS. 6A to 6C and FIG. 7, each portion shown in FIG. 8 is shaped as a segment of a circle of similar shape, size and proportions as the susceptor plate portions described above. The portions of the susceptor shown in FIG. 8 are again spread over three parallel planes when located in a cartridge. The top and bottom planes have a single portion in them, and the middle plane has two portions. The susceptor portions in the plane with two portions therein are arranged and orientated in the same way as the susceptor portions of FIG. 6A. The susceptor portions in other two planes are arranged relative to each other in the same arrangement as the portions in a single plane. These portions are rotated through 90° about the mid-point of the susceptor plates as described above. When assembled, this provides a square aperture in the centre of the susceptor and a complete circle around the outside of the susceptor when viewed from above or below. The temperature sensor 11 is again located (radially) in the aperture.