Induction heating assembly for a vapour generating device

Abstract

An induction heating assembly (22) for a vapour generating device (10) comprises an induction coil (32) and a heating compartment (24) arranged to receive an inductively heatable cartridge (26). A first electromagnetic shield layer (36) is arranged outside the induction coil (32) and a second electromagnetic shield layer (46) is arranged outside the first electromagnetic shield layer (36). One or both of the electrical and magnetic permeability of the first and second electromagnetic shield layers (36, 46) are different.

Description

[0001] This application is a divisional application of the invention patent application filed on December 20, 2018, with application number 201880084257.6 (international application number PCT / EP2018 / 086177) and entitled "Induction heating assembly for a steam generating device". Technical Field

[0002] This disclosure relates to an induction heating assembly for a steam generating apparatus. Embodiments of this disclosure also relate to a steam generating apparatus. Background Technology

[0003] Devices that heat rather than burn vaporizable substances to produce vapor for inhalation have become increasingly popular with consumers in recent years.

[0004] Such a device can provide heat to a substance using one of several different methods. One such method is a steam-generating device employing an induction heating system. In such a device, an induction coil (hereinafter also referred to as an inductor) is provided, and the vaporizable substance is provided with a sensor. When the user activates the device, electrical energy is supplied to the inductor, which in turn generates an alternating electromagnetic field. The sensor couples with the electromagnetic field and generates heat, which is transferred to the vaporizable substance, for example, through conduction, and steam is produced when the vaporizable substance is heated.

[0005] This approach potentially offers better control over heating and therefore steam generation. However, a drawback of using induction heating systems is the potential for leakage of the electromagnetic field generated by the induction coils, which needs to be addressed. Summary of the Invention

[0006] According to a first aspect of this disclosure, an induction heating assembly for a steam generating apparatus is provided, the induction heating assembly comprising:

[0007] Induction coil;

[0008] A heating compartment, which is configured to receive inductively heated smoke cartridges;

[0009] A first electromagnetic shielding layer is disposed outside the induction coil;

[0010] A second electromagnetic shielding layer is disposed outside the first electromagnetic shielding layer.

[0011] The conductivity and magnetic permeability of the first electromagnetic shielding layer and the second electromagnetic shielding layer are different, or both are different.

[0012] According to a second aspect of this disclosure, an induction heating assembly for a steam generating apparatus is provided, the induction heating assembly comprising:

[0013] Induction coil;

[0014] A heating compartment, which is configured to receive inductively heated smoke cartridges;

[0015] An electromagnetic shielding layer, disposed outside the induction coil, comprising a non-conductive ferromagnetic material; and

[0016] A first insulating layer, positioned between the induction coil and the electromagnetic shielding layer, comprises a material that is substantially non-conductive and has a relative permeability substantially equal to 1.

[0017] According to a third aspect of this disclosure, a steam generating apparatus is provided, comprising:

[0018] Induction heating assembly according to the first or second aspect of this disclosure;

[0019] An air inlet is arranged to supply air to the heated compartment; and

[0020] An air outlet connected to the heated compartment.

[0021] The one or more electromagnetic shielding layers provide a compact, efficient, and lightweight electromagnetic shielding structure that reduces leakage of the electromagnetic field generated by the induction coil. This, in turn, allows for a more compact induction heating assembly, and thus a more compact steam generating device.

[0022] The suppression of current flow in one or more electromagnetic shielding layers reduces heat generation (due to Joule heating) in the shielding structure and thus reduces energy loss. This provides several advantages, including: (i) electromagnetic energy is transferred more efficiently from the induction coil to the sensor associated with the inductively heated cartridge, and thus improves the heating of the vaporizable substance; (ii) a temperature reduction, which causes a decrease in the surface temperature of the vapor-generating device and mitigates potential damage to the device, for example, by preventing plastic components within the device from melting due to excessive temperature; and (iii) protection of other electrical and electronic components within the vapor-generating device.

[0023] In one embodiment, one of the electromagnetic shielding layers comprises a non-conductive ferromagnetic material, while the other electromagnetic shielding layer comprises a conductive material.

[0024] The first electromagnetic shielding layer may comprise a non-conductive ferromagnetic material. Examples of suitable materials for the first electromagnetic shielding layer include, but are not limited to, ferrite, nickel-zinc ferrite, and high-permeability alloys. The first electromagnetic shielding layer may comprise a laminated structure and therefore may comprise multiple layers. These layers may comprise the same material or may comprise a variety of different materials, for example, selected to provide the desired shielding properties. The first electromagnetic shielding layer may, for example, comprise one or more layers of ferrite and one or more layers of adhesive material.

[0025] The thickness of the first electromagnetic shielding layer can be between 0.1 mm and 10 mm. In some embodiments, the thickness can be between 0.1 mm and 6 mm, and more preferably, the thickness can be between 0.7 mm and 2.0 mm.

[0026] The first electromagnetic shielding layer can provide a coverage area greater than 80% of the complete surface area of ​​the first electromagnetic shielding layer. In some embodiments, the coverage area can be greater than 90%, possibly greater than 95%. As used herein, complete surface area means the surface area of ​​the layer when it is intact, for example, without any openings such as air inlets or outlets within the layer. As used herein, coverage area means the surface area excluding the area of ​​any openings such as air inlets or outlets within the layer.

[0027] The second electromagnetic shielding layer may include a conductive material. The second electromagnetic shielding layer may include a mesh. The second electromagnetic shielding layer may include a metal. Examples of suitable metals include, but are not limited to, aluminum and copper. The second electromagnetic shielding layer may include a laminated structure and therefore may comprise multiple layers. These layers may include the same material or may include a variety of different materials, for example, selected to provide the desired shielding properties.

[0028] The thickness of the second electromagnetic shielding layer can be between 0.1 mm and 0.5 mm. In some embodiments, the thickness can be between 0.1 mm and 0.2 mm. The resistance of the second electromagnetic shielding layer can be less than 30 mΩ. The resistance can be less than 15 mΩ and less than 10 mΩ. These resistance values ​​minimize heat and conduction losses in the second electromagnetic shielding layer.

[0029] The second electromagnetic shielding layer can provide a coverage area greater than 30% of the complete surface area of ​​the second electromagnetic shielding layer. In some embodiments, the coverage area can be greater than 50%, possibly greater than 65%. The coverage area of ​​the second electromagnetic shielding layer can be significantly smaller than the coverage area of ​​the first electromagnetic shielding layer because, as described above, the second electromagnetic shielding layer may include a mesh.

[0030] The second electromagnetic shielding layer may include a substantially cylindrical shielding portion and may include a substantially cylindrical sleeve. The cylindrical shielding portion may include a circumferential gap. Therefore, the second electromagnetic shielding layer may include a cylindrical sleeve, wherein the circumferential gap extends along the entire sleeve in the axial direction. The circumferential gap provides an electrical interruption in the second electromagnetic shielding layer, thereby limiting the occurrence of induced current at that point.

[0031] In some embodiments, there is no conductive material between the induction coil and the first electromagnetic shielding layer. This arrangement helps to suppress current in the shielding structure.

[0032] The induction heating assembly may include a first insulating layer. This first insulating layer may be positioned between the induction coil and a first electromagnetic shielding layer. The first insulating layer may be substantially non-conductive, and its relative permeability may be substantially equal to 1. A relative permeability substantially equal to 1 means that the relative permeability may be in the range of 0.99 to 1.01, preferably in the range of 0.999 to 1.001.

[0033] The first insulating layer may comprise only a material that is substantially non-conductive and has a relative permeability substantially equal to 1. Alternatively, the first insulating layer may comprise a material that is substantially non-conductive and has a relative permeability substantially equal to 1. The first insulating layer may, for example, comprise a laminated structure or a composite structure, and may itself comprise a mixture of multiple layers and / or particles / elements. These layers or mixtures of particles / elements may comprise the same material or may comprise a variety of different materials, for example, one or more materials selected from the group consisting of non-conductive materials, conductive materials, and ferromagnetic materials. It should be understood that such material combinations will be provided in proportion to ensure that the first insulating layer "substantially" comprises a material that is substantially non-conductive and has a relative permeability substantially equal to 1. In one embodiment, the material of the first insulating layer may comprise air.

[0034] The thickness of the first insulating layer can be between 0.1 mm and 10 mm. In some embodiments, the thickness can be between 0.5 mm and 7 mm, and possibly between 1 mm and 5 mm. This arrangement including the first insulating layer ensures that the induction coil generates an optimal alternating electromagnetic field.

[0035] The first insulating layer can provide a coverage area greater than 90% of the complete surface area of ​​the first insulating layer. In some embodiments, the coverage area can be greater than 95%, possibly greater than 98%.

[0036] The induction heating assembly may further include an air passage from an air inlet to a heating chamber, and this air passage may form at least a portion of the first insulating layer. This simplifies the construction of the induction heating assembly and minimizes its size, and thus the size of the steam generating device. Heat from the induction coil can also be transferred to the air flowing through the air passage, thereby improving the efficiency of the induction heating assembly and thus the efficiency of the steam generating device due to preheating of the air.

[0037] The induction heating assembly may further include a housing, and the housing may include a second electromagnetic shielding layer. This arrangement of using the housing as the second electromagnetic shielding layer reduces the number of components and thus improves the size, weight, and manufacturing cost of the induction heating assembly, and consequently improves the size, weight, and manufacturing cost of the steam generating device.

[0038] One or both of the first electromagnetic shielding layer and the second electromagnetic shielding layer can be arranged circumferentially around the induction coil at the first and second axial ends of the induction coil, so as to substantially surround the induction coil. This maximizes the shielding effect.

[0039] In one embodiment, the induction heating component may further include:

[0040] A suction passage extends at the first axial end of the induction heating assembly, between the heating chamber and the air outlet; wherein...

[0041] A portion of the intake passage extends between the heated compartment and the air outlet in a direction substantially perpendicular to the axial direction; and

[0042] One or both of the first and second electromagnetic shielding layers extend adjacent to the portion of the intake passage, such that the first axial end of the induction coil is substantially covered by these electromagnetic shielding layers.

[0043] This arrangement of the first electromagnetic shielding layer and / or the second electromagnetic shielding layer ensures maximum coverage of the first axial end of the induction coil through the first electromagnetic shielding layer and / or the second electromagnetic shielding layer, and ensures that the shielding effect is maximized.

[0044] The induction heating assembly may further include a shielded coil, which may be positioned at one or both of a first axial end and a second axial end of the induction coil, possibly located within a first electromagnetic shielding layer or a second electromagnetic shielding layer. The shielded coil can operate as a low-pass filter, thereby reducing the number of components and thus resulting in improvements in the size, weight, and manufacturing cost of the induction heating assembly, and consequently, the size, weight, and manufacturing cost of the steam generating device.

[0045] The induction heating assembly may further include an outer housing layer that surrounds a first electromagnetic shielding layer and a second electromagnetic shielding layer. This ensures that the outer surface of the steam generating device does not heat up and that the user can operate the device without any discomfort.

[0046] In one embodiment, the induction heating assembly may further include a second insulating layer. The second insulating layer may be substantially non-conductive and its relative permeability may be less than or substantially equal to 1. A relative permeability substantially equal to 1 means that the relative permeability can be in the range of 0.99 to 1.01, preferably in the range of 0.999 to 1.001. A first portion of the second insulating layer is located between the induction coil and the vaporizable material inside the inductively heated cartridge during use. This arrangement including the second insulating layer ensures optimal coupling between the sensor and the alternating electromagnetic field. A second portion of the second insulating layer may be disposed outside the induction coil and may be positioned between the induction coil and the first electromagnetic shielding layer.

[0047] The second insulating layer may comprise only a material that is substantially non-conductive and has a relative permeability less than or substantially equal to 1. Alternatively, the second insulating layer may comprise a material that is substantially non-conductive and has a relative permeability less than or substantially equal to 1. The second insulating layer may, for example, comprise a laminated structure or a composite structure, and may itself comprise a mixture of multiple layers and / or particles / elements. These layers or mixtures of particles / elements may comprise the same material or may comprise a variety of different materials, for example, one or more materials selected from the group consisting of non-conductive materials, conductive materials, and ferromagnetic materials. It should be understood that such material combinations will be provided in proportion to ensure that the second insulating layer "substantially" comprises a material that is substantially non-conductive and has a relative permeability less than or substantially equal to 1.

[0048] In one embodiment, the second insulating layer may comprise a plastic material. The plastic material may comprise polyetheretherketone (PEEK) or any other material with very high thermal resistivity (insulator) and low thermal mass. It should be understood that after the steam generating device has been deactivated for a period of time, the components of the device, and consequently the components of the induction heating assembly, will cool down until they reach ambient temperature. When the steam generating device is initially activated upon contact with heated steam in the second insulating layer, condensation may form on the second insulating layer due to the contact between the relatively hot steam and the relatively cool second insulating layer, and this condensation will persist until the temperature of the second insulating layer increases. The use of a material with very high thermal resistivity and low thermal mass minimizes condensation because this material ensures that the second insulating layer heats up as quickly as possible after the device is initially activated upon contact with heated steam.

[0049] The induction heating component can be arranged to operate by a fluctuating electromagnetic field during use, the fluctuating electromagnetic field having a magnetic flux density between approximately 20 mT and approximately 2.0 T at the point of maximum concentration.

[0050] The induction heating assembly may include a power supply and circuitry configured to operate at high frequencies. The power supply and circuitry may be configured to operate at frequencies between approximately 80 kHz and 500 kHz, possibly between approximately 150 kHz and 250 kHz, and possibly around 200 kHz. Depending on the type of inductive heating sensor used, the power supply and circuitry may be configured to operate at even higher frequencies, such as those in the MHz range.

[0051] Although induction coils can be made of any suitable material, they typically include Litz wire or Litz cable.

[0052] Although induction heating components can take any shape and form, they can be arranged essentially in the form of induction coils to reduce the use of excess material. The shape of the induction coil can be essentially helical.

[0053] The circular cross-section of the spiral induction coil facilitates the insertion of the induction-heating cartridge into the induction heating assembly and ensures uniform heating of the cartridge. The resulting induction heating assembly is also comfortable for the user to hold.

[0054] The inductively heated cartridge may include one or more inductively heated sensors. The sensor, or each sensor, may be one or more of aluminum, iron, nickel, stainless steel, and their alloys (e.g., nickel-chromium or nickel-copper alloys). By applying an electromagnetic field in its vicinity, the sensor, or each sensor, may generate heat due to eddy currents and hysteresis losses, thereby causing a conversion of electromagnetic energy into thermal energy.

[0055] Induction-heated cartridges may include vapor-generating material within a permeable shell. The permeable shell may include an electrically insulating and non-magnetic permeable material. This material may have high permeability to allow airflow through a material with high-temperature resistance. Examples of suitable permeable materials include cellulose fibers, paper, cotton, and silk. The permeable material can also be used as a filter. Alternatively, induction-heated cartridges may include vapor-generating material encased in paper. Alternatively, induction-heated cartridges may include vapor-generating material fixed within a material that is impermeable but includes suitable perforations or openings to allow airflow. Alternatively, induction-heated cartridges may consist of the vapor-generating material itself. Induction-heated cartridges may be substantially rod-shaped.

[0056] The vapor-generating substance can be any type of solid or semi-solid material. Exemplary types of vapor-generating solids include powders, microparticles, pellets, fragments, threads, granules, gels, strips, loose leaves, shredded fillers, porous materials, foam materials, or sheets. The substance may include plant-derived materials, and in particular, it may include tobacco.

[0057] The vapor-generating material may include an aerosol forming agent. Examples of aerosol forming agents include polyols and mixtures thereof, such as glycerol or propylene glycol. Typically, the vapor-generating material may include an aerosol forming agent content of between about 5% and about 50% (based on dry weight). In some embodiments, the vapor-generating material may include an aerosol forming agent content of about 15% (based on dry weight).

[0058] Furthermore, the vapor-generating substance can be the aerosol forming agent itself. In this case, the vapor-generating substance can be a liquid. Moreover, in this case, the induction-heated cartridge can include a liquid-holding material (e.g., fiber bundles, porous materials such as ceramics, etc.), which holds the liquid vaporized and allows vapor to form and be released / emitted from the liquid-holding material, for example, toward an air outlet for the user to inhale.

[0059] When heated, the vapor-producing substances can release volatile compounds. These volatile compounds can include nicotine or flavor compounds such as tobacco flavorings.

[0060] Because the induction coil generates an electromagnetic field when it operates to heat the sensor, any component including the inductively heated sensor will be heated when placed near the induction coil during operation, and this does not limit the shape and form of the body received by the heating compartment. In some embodiments, the inductively heated cartridge may be cylindrical in shape, and therefore the heating compartment is arranged to receive a substantially cylindrical vaporizable article.

[0061] The ability of the heating compartment to receive the essentially cylindrical induction-heated tobacco cartridges to be heated is advantageous because vaporizable substances, especially tobacco products, are typically packaged and sold in cylindrical form. Attached Figure Description

[0062] Figure 1 This is a schematic illustration of a steam generating apparatus, which includes an induction heating component according to a first embodiment of the present disclosure;

[0063] Figures 2 to 4 It is a graphical illustration of the shielding effect obtained by using electromagnetic shielding layers according to various aspects of the present disclosure and the change in magnetic field strength obtained by using insulating layers according to various aspects of the present disclosure;

[0064] Figure 5 This is a schematic illustration of a portion of an induction heating assembly according to a second embodiment of the present disclosure; and

[0065] Figure 6 This is a schematic illustration of a portion of an induction heating assembly according to a third embodiment of the present disclosure. Detailed Implementation

[0066] Embodiments of this disclosure will now be described by way of example only and with reference to the accompanying drawings.

[0067] First refer to Figure 1 The diagram illustrates a steam generating device 10 according to an example of this disclosure. The steam generating device 10 includes a housing 12. When the device 10 is used to generate steam for inhalation, a mouthpiece 18 can be mounted on the device 10 at an air outlet 19. The mouthpiece 18 has the capability to allow a user to easily inhale the steam generated by the device 10. The device 10 includes a power supply and control circuitry system, designated by reference numeral 20, which can be configured to operate at high frequencies. The power supply typically includes, for example, one or more batteries capable of sensing recharging. The device 10 also includes an air inlet 21.

[0068] The vapor generating device 10 includes an induction heating assembly 22 for heating the vapor-generating (i.e., vaporizable) substance. The induction heating assembly 22 includes a generally cylindrical heating chamber 24 arranged to receive a correspondingly cylindrical inductively heated cartridge 26, which includes a vaporizable substance 28 and one or more inductively heated sensors 30. The inductively heated cartridge 26 typically includes an outer layer or membrane to contain the vaporizable substance 28, wherein the outer layer or membrane is permeable. For example, the inductively heated cartridge 26 may be a disposable cartridge 26 containing tobacco and at least one inductively heated sensor 30.

[0069] The induction heating assembly 22 includes a helical induction coil 32 extending around a cylindrical heating chamber 24 and energized by a power supply and control circuitry system 20. Those skilled in the art will understand that when the induction coil 32 is energized, an alternating and time-varying electromagnetic field is generated. This alternating and time-varying electromagnetic field couples with one or more inductive heating sensors 30 and generates eddy currents and / or hysteresis losses in the sensors 30, thereby causing them to heat up. The heat is then transferred from the one or more inductive heating sensors 30 to the vaporizable material 28, for example, through conduction, radiation, and convection.

[0070] Multiple inductively heated sensors 30 can be in direct or indirect contact with the vaporizable substance 28, such that when the induction coil 32 of the induction heating assembly 22 inductively heats the sensors 30, heat is transferred from the sensors 30 to the vaporizable substance 28 to heat it and generate vapor. Air from the surrounding environment is added through the air inlet 21, promoting the vaporization of the vaporizable substance 28. The vapor generated by heating the vaporizable substance 28 then exits the heating chamber 24 through the air outlet 19 and can be inhaled, for example, by a user of the device 10 through the mouthpiece 18. The negative pressure created by the user drawing air from the air outlet 19 side of the device 10 using the mouthpiece 18 helps the airflow through the heating chamber 24, i.e., from the air inlet 21, along the suction passage 34 of the induction heating assembly 22, through the heating chamber 24, and out of the air outlet 19.

[0071] The induction heating assembly 22 includes a first electromagnetic shielding layer 36 disposed outside the induction coil 32, and is typically formed of a non-conductive ferromagnetic material such as ferrite, nickel-zinc ferrite, or a high-permeability alloy. Figure 1 In the illustrated embodiment, the first electromagnetic shielding layer 36 includes a substantially cylindrical (e.g., substantially cylindrical sleeve-shaped) shielding portion 38 radially positioned outside the helical induction coil 32 to extend circumferentially around the induction coil 32. The thickness of the substantially cylindrical shielding portion 38 (in the radial direction) is typically between approximately 1.7 mm and 2 mm. The first electromagnetic shielding layer 36 also includes a first annular shielding portion 40 disposed at a first axial end portion 14 of the induction heating assembly 22, the first annular shielding portion having a thickness of approximately 5 mm (in the axial direction). The first electromagnetic shielding layer 36 also includes a second annular shielding portion 42 disposed at a second axial end portion 16 of the induction heating assembly 22. It should be noted that the second annular shielding portion 42 includes a first shielding material 42a and a second shielding material 42b, with an optional shielding coil 44 positioned between the first and second shielding materials. In an alternative embodiment, the second annular shielding portion 42 may include a single layer of shielding material, with or without the shielding coil 44.

[0072] The induction heating assembly 22 includes a second electromagnetic shielding layer 46 disposed outside the first electromagnetic shielding layer 36. The second electromagnetic shielding layer 46 typically comprises a conductive material (e.g., a metal such as aluminum or copper) and may be in the form of a mesh. Figure 1In the illustrated embodiment, the second electromagnetic shielding layer 46 includes a substantially cylindrical shielding portion 48 (e.g., in the form of a substantially cylindrical sleeve with an axially extending circumferential gap (not shown)) and an annular shielding portion 50 disposed at a first axial end 14 of the induction heating assembly 22. The substantially cylindrical shielding portion 48 and the annular shielding portion 50 may be integrally formed as a single component. In some embodiments, the thickness of the second electromagnetic shielding layer 46 is approximately 0.15 mm. The resistance value of the second electromagnetic shielding layer 46 is selected to minimize heat and conduction losses in the second electromagnetic shielding layer 46, and its value may be, for example, less than 30 mΩ.

[0073] The induction heating assembly 22 includes an outer shell layer 13 that surrounds a first electromagnetic shielding layer 36 and a second electromagnetic shielding layer 46 and forms the outermost layer of the housing 12. In an alternative embodiment (not shown), the outer shell layer 13 may be omitted, such that the second electromagnetic shielding layer 46 forms the outermost layer of the housing 12.

[0074] The induction heating assembly 22 includes a first insulating layer 52 positioned between the induction coil 32 and the first electromagnetic shielding layer 36. The first insulating layer 52 is substantially non-conductive and has a relative permeability substantially equal to 1, and in the illustrated embodiment, the first insulating layer 52 comprises air.

[0075] Providing a first insulating layer 52 between the induction coil 32 and the first electromagnetic shielding layer 36 advantageously ensures the generation of an optimal electromagnetic field for coupling with the plurality of sensors 30 of the inductively heated cartridge 26, and this in Figures 2 to 4 This is illustrated in the diagram. For example, Figure 2 The diagram illustrates the electromagnetic field generated by the spiral induction coil 32 in the absence of the aforementioned electromagnetic shielding layers 36 and 46. On the other hand, Figure 3 The diagram illustrates the electromagnetic field generated by the spiral induction coil 32 when the aforementioned first electromagnetic shielding layer 36, particularly the substantially cylindrical shielding portion 38, is positioned very close to or in contact with the induction coil 32 (in other words, when the aforementioned first insulating layer 52 is not provided). Figure 3 It can be readily seen that while the first electromagnetic shielding layer 36 reduces the intensity of the electromagnetic field in its radially outward region and thus reduces electromagnetic field leakage, it also reduces the intensity of the electromagnetic field in the radially inward region of the induction coil 32 where the inductively heated cartridge 26 is located during use. This is undesirable because it adversely affects the coupling of the electromagnetic field with the (multiple) sensors 30 of the inductively heated cartridge 26 and reduces heating efficiency. (See final reference...) Figure 4It will be apparent that when the first insulating layer 52 according to various aspects of this disclosure is positioned between the induction coil 32 and the first electromagnetic shielding layer 36, the first electromagnetic shielding layer 36 (especially the substantially cylindrical shielding portion 38) is in contact with... Figure 3 The method shown reduces the intensity of the electromagnetic field in the radially outward region of the first electromagnetic shielding layer 36, thereby reducing electromagnetic field leakage. However, compared with... Figure 3 In contrast, the intensity of the electromagnetic field in the radially inward region of the induction coil 32 (where the inductively heated cartridge 26 is positioned during use) is not reduced, thereby ensuring optimal coupling between the electromagnetic field and the (multiple) sensors 30 of the inductively heated cartridge 26 and maximizing heating efficiency.

[0076] For reference here Figure 1 It should be noted that the induction heating assembly 22 includes an annular air passage 54 extending from the air inlet 21 to the heating chamber 24. The air passage 54 is radially positioned outside the induction coil 32, between the induction coil 32 and the first electromagnetic shielding layer 36, and the first insulating layer 52 is at least partially formed by the air passage 54.

[0077] The induction heating assembly 22 further includes a second insulating layer 58. Figure 1 The lieutenant general observed that the first portion 58a of the second insulating layer 58 was arranged inside the induction coil 32, such that this first portion was between the induction coil 32 and the vaporizable material 28 inside the inductively heated cartridge 26. Figure 1 As will also be seen, a second portion 58b of the second insulating layer 58 is disposed outside the induction coil 32 and positioned between the induction coil 32 and the first electromagnetic shielding layer 36. In the illustrated embodiment, the second portion 58b includes a cylindrical sleeve 56 radially positioned outside the annular air passage 54 and adjacent to the first electromagnetic shielding layer 36. The second insulating layer 58 is substantially non-conductive and has a relative permeability less than or substantially equal to 1, and typically comprises a plastic material such as PEEK. Figure 1 It should be understood that the first portion 58a of the second insulating layer 58 defines the internal volume of the heating chamber 24 that receives the inductively heated smoke cartridge 26 during use.

[0078] Now for reference Figure 5 This shows a portion of a second embodiment of the induction heating assembly 60 for the steam generating device 10. Figure 5 The induction heating component 60 shown is... Figure 1 The induction heating assembly 22 shown is similar, and the same reference numerals are used to identify corresponding parts. It should be noted that... Figure 5The basically cylindrical shielding portions 38 and 48 of the first electromagnetic shielding layer 36 and the second electromagnetic shielding layer 46 are omitted.

[0079] The induction heating assembly 60 includes a suction passage 62 extending from the heating chamber 24 to the air outlet 19 at a first axial end 14 of the induction heating assembly 60. The suction passage 62 includes a first axial portion 64 and a second axial portion 66 extending between the heating chamber 24 and the air outlet 19 in a direction substantially parallel to the axial direction. The suction passage 62 also includes a transverse portion 68 extending between the heating chamber 24 and the air outlet 19 in a direction substantially perpendicular to the axial direction. A plurality of electromagnetic shielding assemblies, each including a first electromagnetic shielding layer 36 and a second electromagnetic shielding layer 46, are positioned adjacent to the transverse portion of the suction passage 62 on opposite sides of the transverse portion 68. With this arrangement, the electromagnetic shielding assemblies at least partially overlap each other, such that the first axial end of the induction coil 32 is substantially shielded by the electromagnetic shielding layers 36, 46.

[0080] Now for reference Figure 6 This shows a portion of a third embodiment of the induction heating assembly 70 for the steam generating device 10. Figure 6 The induction heating component 70 shown is... Figure 5 The induction heating assembly 60 shown is similar, and the same reference numerals are used to identify the corresponding parts.

[0081] The induction heating assembly 70 includes a suction passage 72 extending from the heating chamber 24 to the air outlet 19 at a first axial end 14 of the induction heating assembly 70. The suction passage 72 includes a first axial portion 74, a second axial portion 76, a third axial portion 78, and a fourth axial portion 80, which extend between the heating chamber 24 and the air outlet 19 in a direction substantially parallel to the axial direction. The suction passage 72 also includes a first transverse portion 82, a second transverse portion 84, and a third transverse portion 86, which extend between the heating chamber 24 and the air outlet 19 in a direction substantially perpendicular to the axial direction. A plurality of electromagnetic shielding assemblies, each including a first electromagnetic shielding layer 36 and a second electromagnetic shielding layer 46, are again positioned adjacent to the transverse portions 82, 84, and 86 of the suction passage 72 on opposite sides of the transverse portion 84. With this arrangement, it should again be understood that the electromagnetic shielding assemblies at least partially overlap each other, such that the first axial end of the induction coil 32 is substantially shielded by the electromagnetic shielding layers 36 and 46.

[0082] While exemplary embodiments have been described in the foregoing paragraphs, it should be understood that various modifications may be made to these embodiments without departing from the scope of the appended claims. Therefore, the breadth and scope of the claims should not be limited to the exemplary embodiments described above.

[0083] Unless the context clearly requires otherwise, throughout the specification and claims, the words “comprising,” “including,” etc., should be interpreted in a meaning that includes rather than excludes or exhausts; that is, in the meaning of “including but not limited to.”

Claims

1. An induction heating assembly (22) for a steam generating device (10), the induction heating assembly (22) comprising: Induction coil (32); A heating compartment (24) is arranged to receive an inductively heated smoke cartridge (26); A first electromagnetic shielding layer (36) is arranged outside the induction coil (32); A second electromagnetic shielding layer (46) is disposed outside the first electromagnetic shielding layer (36); and A first insulating layer (52) is located between the induction coil (32) and the first electromagnetic shielding layer (36); The first electromagnetic shielding layer (36) and the second electromagnetic shielding layer (46) have different electrical conductivity and magnetic permeability, or both. The first electromagnetic shielding layer (36) comprises a non-conductive ferromagnetic material; and The second electromagnetic shielding layer (46) comprises a conductive material.

2. The induction heating assembly (22) according to claim 1, wherein, The first electromagnetic shielding layer (36) includes multiple layers, which include one or more layers of ferrite and one or more layers of adhesive material.

3. The induction heating assembly (22) according to claim 1, wherein, The thickness of the first electromagnetic shielding layer (36) is 0.1mm-10mm.

4. The induction heating assembly (22) according to claim 1, wherein, The thickness of the first electromagnetic shielding layer (36) is 0.1mm-6mm.

5. The induction heating assembly (22) according to claim 1, wherein, The thickness of the first electromagnetic shielding layer (36) is 0.1mm-0.7mm.

6. The induction heating assembly (22) according to claim 1, wherein, The thickness of the first electromagnetic shielding layer (36) is 0.7mm-2.0mm.

7. The induction heating assembly (22) according to claim 1, wherein, The thickness of the first electromagnetic shielding layer (36) is 0.1mm-2.0mm.

8. The induction heating assembly (22) according to claim 1, wherein, The thickness of the second electromagnetic shielding layer (46) is 0.1mm-0.5mm.

9. The induction heating assembly (22) according to claim 1, wherein, The resistance of the second electromagnetic shielding layer (46) is less than 30mΩ.

10. The induction heating assembly (22) according to claim 1, wherein, The second electromagnetic shielding layer (46) includes a shielding portion that is substantially cylindrical.

11. The induction heating assembly (22) according to claim 10, wherein, The second electromagnetic shielding layer (46) includes a sleeve that is substantially cylindrical.

12. The induction heating assembly (22) according to any one of claims 1-11, wherein, There is no conductive material between the induction coil (32) and the first electromagnetic shielding layer (36).

13. The induction heating assembly (22) according to claim 9, wherein, The first insulating layer (52) is non-conductive and has a relative permeability of 1.

14. The induction heating assembly (22) according to claim 13, wherein, The first insulating layer (52) includes air.

15. The induction heating assembly (22) according to any one of claims 1-11, further comprising a housing (12), wherein, The housing (12) includes the second electromagnetic shielding layer (46).

16. The induction heating assembly (22) according to claim 15, further comprising a housing (12), wherein, The second electromagnetic shielding layer comprises one or more of aluminum and copper.

17. The induction heating assembly (22) according to any one of claims 1-11, further comprising an outer shell layer (13) surrounding the first electromagnetic shielding layer (36) and the second electromagnetic shielding layer (46).

18. The induction heating assembly (22) according to any one of claims 1-11, further comprising: A second insulating layer (58), wherein a portion (58a) of the second insulating layer (58) is located between the induction coil (32) and the vaporizable material inside the inductively heated smoke cartridge (26) during use.

19. The induction heating assembly (22) according to claim 18, wherein, The second insulating layer (58) is non-conductive and its relative permeability is less than or equal to 1.

20. The induction heating assembly (22) according to claim 19, wherein, The second insulating layer (58) comprises a plastic material.

21. The induction heating assembly (22) according to any one of claims 1-11, further comprising: power supply; as well as Circuit; The power supply and circuitry are configured to operate at frequencies ranging from 80 kHz to 500 kHz.

22. The induction heating assembly (22) according to claim 21, in, The power supply and circuitry are configured to operate at frequencies ranging from 80 kHz to 250 kHz.

23. A steam generating apparatus (10), comprising: The induction heating assembly (22) according to any of the preceding claims; An air inlet (21) is arranged to supply air to the heated compartment (24); as well as An air outlet (19) connected to the heating compartment (24).

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