Induction heating assembly for a vapour generating device

Abstract

An induction heating assembly for a vapour generating device includes an outer body; an induction coil arranged inward of the outer body; a heating compartment defined inward of the induction coil and arranged to receive, in use, a body comprising a vaporisable substance and an induction heatable susceptor; wherein the separation between the outer body and the induction coil defines an air vent arranged to allow air flow around the induction coil and to the heating compartment.

Claims

1. An induction heating assembly for a vapour generating device, the heating assembly comprising: an outer body; an induction coil arranged inward of the outer body; a heating compartment defined inward of the induction coil and arranged to receive, in use, a body comprising a vaporisable substance and an induction heatable susceptor; wherein a separation between the outer body and the induction coil defines an air vent arranged to allow air flow around the induction coil and to the heating compartment, and wherein the induction coil is arranged within a wall housing the heating compartment, the wall separating the induction coil from the heating compartment.

2. The induction heating assembly according to claim 1, wherein the air vent is shaped to direct air flow around the induction coil before directing air flow to the heating compartment.

3. The induction heating assembly according to claim 1, further comprising one or more separators arranged between the outer body and induction coil to divide the air vent into two or more layers.

4. The induction heating assembly according to claim 3, wherein the two or more layers of the air vent are arranged to provide an air flow path passing through a plurality of the two or more air vent layers passing from one air vent layer to another air vent layer.

5. The induction heating assembly according to claim 3, wherein the two or more layers of the air vent are arranged to provide an air flow path that passes through at least two of the two or more air vent layers by splitting between each respective air vent layer.

6. The induction heating assembly according to claim 1, further comprising ribs supporting the outer body and the induction coil in mechanical connection, and dividing the air vent into segments.

7. The induction heating assembly according to claim 1, further comprising structures in the air vent arranged to define one or more air flow paths.

8. The induction heating assembly according to claim 7, wherein the one or more air flow paths are arranged to be one or more of: a spiral around the induction coil; a zig-zag in a longitudinal direction of the induction coil; and a zig-zag in a transverse direction of the induction coil.

9. The induction heating assembly according to claim 7, wherein the one or more air flow paths cover more than 50% of an outer surface of the induction coil.

10. The induction heating assembly according to claim 3, further comprising an electromagnetic shield, the shield being arranged: between the induction coil and the air vent; between concentric layers of the two or more air vent layers; substantially surrounding a circumference of the air vent; or being part of a wall of the air vent.

11. The according to claim 1, further comprising an induction heatable susceptor having a tubular shape forming at least part of the air vent.

12. A vapour generating system comprising: the induction heating assembly according to claim 1; a body comprising a vaporisable substance and an induction heatable susceptor; wherein the body is, in use, arranged within the heating compartment of the assembly.

13. The vapour generating system according to claim 12, wherein the vaporisable substance and the induction heatable susceptor are contained by an air permeable layer or an air permeable membrane.

14. The vapour generating system according to claim 12, wherein the vaporisable substance is a solid or semi-solid tobacco substance.

15. The vapour generating system according to claim 12, wherein the susceptor is held within and surrounded by the vaporisable substance such that the vaporisable substance forms, in use, a heat absorbing layer between the susceptor and an outer surface of the assembly.

16. The induction heating assembly according to claim 3, further comprising ribs supporting the outer body, the induction coil, and the one or more separators in mechanical connection, and dividing the air vent into segments.

17. A vapor generating system comprising: an induction heating assembly for a vapor generating device including: an outer body; an induction coil arranged inward of the outer body; a heating compartment defined inward of the induction coil; wherein a separation between the outer body and the induction coil defines an air vent arranged to allow air flow around the induction coil and to the heating compartment; and a body comprising a vaporisable substance and an induction heatable susceptor; wherein the body is, in use, positioned within the heating compartment of the assembly; and wherein the vaporisable substance and the induction heatable susceptor are contained by an air permeable layer or an air permeable membrane.

Description

BRIEF DESCRIPTION OF FIGURES

(1) An example of an induction heating assembly is 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 an example vapour generating device;

(4) FIG. 3 shows a cross-section of the vapour generating device shown in FIG. 2 along plane A-A in FIG. 2;

(5) FIG. 4 shows a cross-section of an alternative example vapour generating device along the same plane as shown in FIG. 3;

(6) FIG. 5 shows a cross-section of a further example vapour generating device along the same plane as shown in FIG. 3;

(7) FIG. 6 shows a cross-section of another example vapour generating device along the same plane as shown in FIG. 3;

(8) FIG. 7 shows a partial schematic view of an example corresponding to the example of FIG. 6;

(9) FIG. 8 shows a partial schematic view of an alternative example corresponding to the example of FIG. 6;

(10) FIG. 9 shows a schematic of a portion of an example vapour generating device with an example air flow path; and

(11) FIG. 10 shows a schematic of a portion of an example vapour generating device with an alternative example air flow path.

DETAILED DESCRIPTION

(12) We now describe an example of a vapour generating device, including a description of an example induction heating assembly and an example induction heatable cartridge. An example method of monitoring temperature in a vapour generating device is also described.

(13) 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.

(14) 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.

(15) In this example, a user inhales the vapour by drawing air into the device 1, 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.

(16) 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 susceptor is 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.

(17) 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.

(18) 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.

(19) As mentioned above, in order for vapour to be produced, the cartridge 20 is heated. This is achieved by an alternating electrical current changed from a direct electrical current 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.

(20) 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. As mentioned above, 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.

(21) 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.

(22) The induction coil 16 is embedded in a wall 28. This restricts contact between the induction coil and the environment around the induction coil. In use, heat passes from the heating compartment 12 into the wall in which the induction coil is embedded, which also provides the side walls to the heating compartment. The induction coil also generates small quantities of heat due to the resistance of the coil.

(23) In order to make use of this heat and to transfer heat away from the induction coil to cool the induction coil, the air inlet 14, which, as mentioned above, is connected to the base of the heating compartment, passes from an opening at one end of the induction coil adjacent where the mouthpiece 30 and the induction heating assembly 10 meet, past the wall within which the induction coil is embedded to the opposing end of the induction coil, across this end to the opening in the base of the heating compartment. When a user draws air through the air outlet 32 in the mouthpiece, air is pulled through the air inlet (as indicated by arrow 48 in FIG. 1) into the heating compartment, through the cartridge (should one be present) and through the air outlet (as indicted by arrow 50 in FIG. 1).

(24) When the air in the air inlet 14 is cooler than the wall 28 in which the induction coil 16 is embedded, heat is transferred from the wall (and therefore from the induction coil) to the air. This warms the air and cools the wall and induction coil. The air that passes through the cartridge is therefore warmer than the air outside of the vapour generating device 1.

(25) In the example shown in FIGS. 1 and 2, the air inlet 14 is enclosed by an outer wall 34. The outer wall provides a barrier between the air inlet and the exterior of the vapour generating device 1. Should the outer wall be warmer than the air in the air inlet, heat is also transferred from the outer wall to the air in the air inlet.

(26) As mentioned above, the air passes into the heating compartment 12 from the air inlet 14 as indicated by arrow 48. The cartridge 20 is a close fit with the heating compartment. As such, the air must pass through the cartridge when passing through the heating compartment containing a cartridge. Air flow around the cartridge is therefore restricted and there is no intentional air flow path around the cartridge between the cartridge and the wall 28 within which the induction coil 16 is embedded. Since the air passing into the heating compartment has been warmed before it enters the heating compartment and cartridge, it limits the amount of heat lost from the cartridge to the air, which keeps the cartridge warmer.

(27) In FIG. 2 there is an EM shield 36 that is embedded in the wall 28 within which the induction coil 16 is embedded. The EM shield is located on the radially outer side of the induction coil. When the vapour generating device 1 is in use, the EM shield will become warm due to the heat produced by the induction coil and in the heating compartment 12, and may become warm due to the currents produced in the shield due to the shielding process.

(28) A cross-section along plane A-A of FIG. 2 is shown in FIG. 3. This shows a circular body, showing that the vapour generating device is generally cylindrical. The heating compartment 12 is in the centre enclosed by a wall 28 within which the induction coil 16 is embedded along with the EM shield 36. As in FIG. 2, it can be seen that the EM shield is located around the induction coil on the radially outer side of the coil.

(29) The air vent 14 is located around the wall 28 within which the induction coil 16 and EM shield 36 are embedded. The air vent is divided into arcs 38, each of which provide an air flow path. The air vent is divided by ribs 40. The ribs are connected between the wall within which the induction coil and EM shield are embedded and the outer wall 34 that surrounds the air vent on its radially outer side.

(30) FIG. 4 shows the same cross-section as shown in FIG. 3 for an alternative example vapour generating device. The device is accordingly still circular with the heating compartment 12 located at its centre. The heating compartment is again enclosed by a wall 28 within which an induction coil 16 and an EM shield 36 are embedded in the same configuration as the vapour generating device shown in FIGS. 2 and 3. Instead of arcs forming air flow paths for the air vent, in this example, the air vent 14 is provided by a plurality of circular bores 39, as in FIG. 4, distributed evenly in a circle on the radially outer side of the EM shield. Each of the bores provides an air flow path and is separated from the adjacent bores by ribs 40 that connect the wall within which the coil and EM shield are embedded to the outer wall 34, which forms the outer wall of the vapour generating device.

(31) The same cross-section of a further alternative example vapour generating device is shown in FIG. 5. The device is again circular with a heating compartment 12 located at is centre. A wall 28 surrounds the heating compartment. The induction coil 16 is embedded within this wall. However, instead of an EM shield also being embedded in this wall as in the example shown in FIG. 3, the EM shield 36 is embedded in the outer wall 34. The outer wall is separated from the wall within which the coil is embedded by the air vent 14. As with the example shown in FIG. 3, the air vent is divided into arcs 38, which are separated by ribs 40. In this configuration the arcs 38 may be provided by a metal tube. In this case the metal tube is able to work as susceptor and provide pre-heating of the air entering the heating compartment 12. The metal tube may also work as an EM shield.

(32) FIG. 6 shows a cross-section of another alternative example vapour generating device along the same plane as FIGS. 3 to 5. In this example the device has the same structure as the example of FIG. 5, but instead of being the outer wall, the wall within which the EM shield is embedded is an intermediate wall 42. Radially outward from this intermediate wall there is an outer wall 34. There is an air vent 14 between the outer wall and the intermediate wall as well as there being an air vent between the intermediate wall and a wall 28 within which the induction coil 16 is embedded and which surrounds a heating compartment 12. Each air vent is divided into arcs 38 by ribs 40 extending between the respective walls for the respective air vent. Each arc again provides an air flow path.

(33) In the example shown in FIG. 6, the air vent 14 can have one of multiple arrangements. Two such arrangements are shown in FIGS. 7 and 8.

(34) FIG. 7 shows an arrangement of an example vapour generating device with a cross-section similar to that shown in FIG. 6. In the arrangement shown in FIG. 7, the vapour generating device has an outer wall 34 that provides the external wall of the device. Radially inward of the outer wall, there is an intermediate wall 42 which has a radial separation from the outer wall and a radial separation from a wall 28 within which an induction coil 16 is embedded. The wall within which the induction coil is embedded is located radially inward of the intermediate wall, and which provides the side walls of a heating compartment 12 defined radially inward of this wall.

(35) There is an air vent 14 that passes from an exterior of the device to the heating compartment. There is a single airflow path running through the air vent, which is indicated at 48 in FIG. 7. The path enters the vapour generating device through the outer wall 34 at a location in line with an axial end of the heating compartment 12. The path then passed between the outer wall and the intermediate wall 42 to a location in line with an opposing axial end of the heating compartment. At this location there is a passage between the gap provided by the radial separation between the outer and intermediate walls and the gap provided by the radial separation between the intermediate wall and the wall 28 within which the induction coil 16 is embedded. The airflow path passes through this passage and returns between the intermediate wall and the wall within which the induction coil is embedded to a location again in line with the initial axial end of the heating compartment, but at a lesser radial separation from the heating compartment than when the path enters the vapour generating device. The path then follows a further passage into the heating compartment at that axial end of the heating compartment.

(36) FIG. 8 shows an alternative arrangement to that shown in FIG. 7 of an example vapour generating device with a cross-section similar to that shown in FIG. 6. As with the arrangement shown in FIG. 7, in the arrangement shown in FIG. 8, the vapour generating device has an outer wall 34 that provides the external wall of the device. Radially inward of the outer wall, there is an intermediate wall 42 which has a radial separation from the outer wall and a radial separation from a wall 28 within which an induction coil 16 is embedded. The wall within which the induction coil is embedded is located radially inward of the intermediate wall, and which provides the side walls of a heating compartment 12 defined radially inward of this wall.

(37) As with FIG. 7, in FIG. 8, there is an air vent 14 that passes from an exterior of the device to the heating compartment. However, instead of the single airflow path 48 of FIG. 7, the arrangement shown in FIG. 8 has an airflow path, indicated at 50 in FIG. 8, which has a common beginning and common end, but has two generally parallel sections between the beginning and end. The path enters the vapour generating device through the outer wall 34 at a location in line with an axial end of the heating compartment 12. The path then spits. One section of the path passes between the outer wall and the intermediate wall 42 in the gap provided by the radial separation of these walls. The other section of the path passes through a passage to the gap provided by the radial separation between the intermediate wall and the wall 28 within which the induction coil 16 is embedded. This section of the path then passes through this gap. The two sections re-join at a location in line with an opposing end of the heating compartment 12. This is achieved by the section of the path passing between the outer wall and the intermediate wall and then passing through a passage in the intermediate wall at to join the section passing between the intermediate wall and the wall within which the induction coil is embedded to the location equivalent to the opposing axial end of the heating compartment. The path then continues along a common end section into the heating compartment at that axial end of the heating compartment.

(38) As with the example shown in FIG. 6, the arrangements shown in FIGS. 7 and 8 have ribs (not shown in FIGS. 7 and 8) that connect and support the various walls forming arc sections in the air vent 14.

(39) FIGS. 9 and 10 each show example air flow paths able to be used in a vapour generation device. Each of these figures shows a cylinder representing the wall 28 within which the induction coil is embedded.

(40) FIG. 9 shows an air flow path 44, which is provided by the air vent (not shown in FIGS. 9 and 10). The air flow path passes around the wall 28 in a zig-zag pattern. By this we intend to mean that the path has parallel sections that are aligned with the longitudinal axis of the cylindrical wall and are joined to adjacent sections by curved sections of air flow path at the ends of the parallel sections. In this configuration one or more air flow paths are arranged around the whole wall.

(41) FIG. 10 shows an air flow path 46. This air flow path is again provided by the air vent (not shown). The air flow path passes around the wall 28 in a spiral passing from one axial end of the wall to the opposing axial end of the wall.