Induction heating assembly for steam generating device

Abstract

To prevent leakage of an electromagnetic field generated by an induction coil.SOLUTION: An induction heating assembly (22) for a vapor generating device (10) includes an induction coil (32) and a heating compartment (24) arranged to receive an induction 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). The first and second electromagnetic shield layers (36, 46) differ in one or both of their electric conductivity and their magnetic permeability.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present disclosure relates to an induction heating assembly for a vapor generating device. Embodiments of the present disclosure also relate to vapor generating devices. 【Background Art】 【0002】 Devices that heat, rather than burn, an evaporable substance to produce vapor for inhalation have gained popularity among consumers in recent years. 【0003】 Such devices can use one of several different approaches to provide heat to the substance. One such approach is to provide a vapor generating device that uses an induction heating system. In such a device, the device is provided with an induction coil (hereinafter also referred to as an inductor), and the susceptor is provided with an evaporable substance. When the user activates the device, electrical energy is provided to the inductor, which in turn generates an alternating electromagnetic field. The susceptor couples with the electromagnetic field and generates heat, for example, transmitted to the evaporable substance by conduction, and when the evaporable substance is heated, vapor is generated. 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 Such an approach can offer better control of heating and thus vapor generation. However, a disadvantage of using an induction heating system is that there may be leakage of the electromagnetic field generated by the induction coil, and thus it is necessary to address this disadvantage. 【Means for Solving the Problems】 【0005】 According to a first aspect of the present disclosure, an induction heating assembly for a vapor generating device, the induction heating assembly comprising an induction coil, and a heating section arranged to receive an induction-heatable cartridge, and A first electromagnetic shielding layer is placed outside the induction coil, A second electromagnetic shielding layer is positioned outside the first electromagnetic shielding layer. Includes, An induction heating assembly is provided in which the first and second electromagnetic shielding layers differ in either their conductivity or their magnetic permeability. 【0006】 According to a second aspect of this disclosure, an induction heating assembly for a steam generating device, wherein the induction heating assembly is An induction coil and A heating compartment positioned to receive an induction heating cartridge, An electromagnetic shielding layer disposed on the outside of an induction coil, comprising an electromagnetic shielding layer containing a ferrimagnetic, non-conductive material, A first insulating layer positioned between an induction coil and an electromagnetic shielding layer, comprising a material that is substantially nonconductive and has a relative magnetic permeability substantially equal to 1. An induction heating assembly is provided, which includes the following. 【0007】 According to a third aspect of this disclosure, a steam generating device, An induction heating assembly according to the first or second aspect of this disclosure, An air inlet positioned to supply air to the heated compartment, An air outlet that is in communication with the heating section and A steam generating device including the following is provided. 【0008】 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, enables the provision of smaller induction heating assemblies and, therefore, smaller steam generating devices. 【0009】 The current flow in one or more electromagnetic shielding layers is suppressed, which reduces the generation of heat in the shielding structure (due to Joule heating) and thereby reduces energy loss. This provides several advantages, including (i) more efficient transfer of electromagnetic energy from the induction coil to the inductively heatable cartridge and associated susceptor, thus improving the heating of the evaporable material; (ii) a decrease in temperature, which leads to a decrease in the surface temperature of the vapor generating device and reduces potential damage to the device by preventing, for example, plastic components within the device from melting due to excessive heat; and (iii) protection of other electrical and electronic components within the vapor generating device. 【0010】 In one embodiment, one electromagnetic shielding layer comprises a ferrimagnetic, non-conductive material, and the other electromagnetic shielding layer comprises a conductive material. 【0011】 The first electromagnetic shielding layer may include ferrimagnetic, nonconductive materials. Suitable materials for the first electromagnetic shielding layer include, but are not limited to, ferrite, nickel-zinc ferrite, and mu-metal. The first electromagnetic shielding layer may include a laminated structure and therefore may include multiple layers. The layers may include the same material or may include multiple different materials selected, for example, to provide desired shielding properties. The first electromagnetic shielding layer may include, for example, one or more layers of ferrite and one or more layers of adhesive material. 【0012】 The first electromagnetic shielding layer may have a thickness of 0.1 mm to 10 mm. In some embodiments, the thickness may be 0.1 mm to 6 mm, and more preferably, 0.7 mm to 2.0 mm. 【0013】 The first electromagnetic shielding layer may provide a coverage area greater than 80% of the total surface area of ​​the first electromagnetic shielding layer. In some embodiments, the coverage area may be greater than 90%, and possibly greater than 95%. As used herein, total surface area means the surface area of ​​the layer when it is completely intact, such as without openings such as air inlets or outlets. As used herein, coverage area means the surface area excluding the area of ​​openings such as air inlets or outlets. 【0014】 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. Suitable metals include, but are not limited to, aluminum and copper. The second electromagnetic shielding layer may include a laminated structure and therefore may include multiple layers. The layers may include the same material or may include multiple different materials selected, for example, to provide desired shielding properties. 【0015】 The second electromagnetic shielding layer may have a thickness of 0.1 mm to 0.5 mm. In some embodiments, the thickness may be 0.1 mm to 0.2 mm. The second electromagnetic shielding layer may have a resistance of less than 30 mΩ. The resistance may be less than 15 mΩ or less than 10 mΩ. These resistance values ​​minimize heating and conductivity losses in the second electromagnetic shielding layer. 【0016】 The second electromagnetic shielding layer may provide a covering area greater than 30% of the total surface area of ​​the second electromagnetic shielding layer. In some embodiments, the covering area may be greater than 50%, and possibly greater than 65%. As described above, since the second electromagnetic shielding layer may include a mesh, the covering area of ​​the second electromagnetic shielding layer may be significantly smaller than the covering area of ​​the first electromagnetic shielding layer. 【0017】 The second electromagnetic shielding layer may include a substantially cylindrical shielding portion or a substantially cylindrical sleeve. The cylindrical shielding portion may include a circumferential gap. Thus, the second electromagnetic shielding layer may include a cylindrical sleeve in which the circumferential gap extends axially along the entire sleeve. The circumferential gap provides electrical interruption in the second electromagnetic shielding layer, thereby limiting the induced current at this point. 【0018】 In some embodiments, there is no conductive material between the induction coil and the first electromagnetic shielding layer. Such an arrangement helps to suppress current flow in the shielding structure. 【0019】 The induction heating assembly may include a first insulating layer. The first insulating layer may be positioned between the induction coil and the first electromagnetic shielding layer. The first insulating layer may be substantially nonconductive and may have a relative permeability 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 0.999 to 1.001. 【0020】 The first insulating layer may consist exclusively of a material that is substantially nonconductive and has a relative permeability substantially equal to 1. Alternatively, the first insulating layer may substantially consist of a material that is substantially nonconductive and has a relative permeability substantially equal to 1. The first insulating layer may include, for example, a laminated or composite structure, and thus may consist of multiple layers and / or mixtures of particles / elements. The layers or mixtures of particles / elements may consist of the same material, or of multiple different materials, e.g., one or more materials selected from the group consisting of nonconductive materials, conductive materials and ferrimagnetic materials. It is understood that such combinations of materials may be provided in proportions that ensure the first insulating layer "substantially" contains a material that is substantially nonconductive and has a relative permeability substantially equal to 1. In one embodiment, the material of the first insulating layer may include air. 【0021】 The first insulating layer may have a thickness of 0.1 mm to 10 mm. In some embodiments, the thickness may be 0.5 mm to 7 mm, and optionally 1 mm to 5 mm. Such an arrangement including the first insulating layer ensures that an optimal alternating electromagnetic field is generated by the induction coil. 【0022】 The first insulating layer may provide a coverage area greater than 90% of the total surface area of the first insulating layer. In some embodiments, the coverage area may be greater than 95%, and optionally greater than 98%. 【0023】 The induction heating assembly may further include an air passage from the air inlet to the heating section, and the air passage may form at least a part of the first insulating layer. This simplifies the structure of the induction heating assembly and enables the size of the induction heating assembly, and thus the steam generating device, to be minimized. Heat from the induction coil may also be transferred to the air flowing through the air passage, and thus improve the efficiency of the induction heating assembly, and thus the steam generating device, due to preheating of the air. 【0024】 The induction heating assembly may further include a housing, and the housing may include a second electromagnetic shielding layer. Such an arrangement in which the housing functions as the second electromagnetic shielding layer results in a reduction in the number of components, and thus improvements in the size, weight and manufacturing cost of the induction heating assembly, and thus the steam generating device. 【0025】 One or both of the first and second electromagnetic shielding layers may be arranged circumferentially around the induction coil and at both the first and second axial ends of the induction coil so as to substantially surround the induction coil. Thus, the shielding effect is maximized. 【0026】 In one embodiment, the induction heating assembly may further include a suction passage extending between the heating section and the air outlet at the first axial end of the induction heating assembly. The portion containing the intake passage extends substantially perpendicular to the axial direction between the heating section and the air outlet. 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 the electromagnetic shielding layer. 【0027】 Such arrangement of the first and / or second electromagnetic shielding layers ensures that the first and / or second electromagnetic shielding layers provide maximum coverage to the first axial end of the induction coil and that the shielding effect is maximized. 【0028】 The induction heating assembly may further include a shielding coil, which may optionally be positioned within a first or second electromagnetic shielding layer at one or both of the first and second axial ends of the induction coil. The shielding coil can act 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 steam generating device. 【0029】 The induction heating assembly may further include an outer housing layer that can surround the first and second electromagnetic shielding layers. This ensures that the outer surface of the steam generating device does not become hot and that the user can handle the device without discomfort. 【0030】 In one embodiment, the induction heating assembly may further include a second insulating layer. The second insulating layer may be substantially nonconductive and may have a relative permeability of less than 1 or 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 0.999 to 1.001. The first portion of the second insulating layer may be located between the induction coil and the evaporable material inside the induction heating cartridge during use. Such an arrangement configuration including the second insulating layer ensures that optimal coupling between the susceptor and the AC electromagnetic field is achieved. The second portion of the second insulating layer may be located outside the induction coil and may be positioned between the induction coil and the first electromagnetic shielding layer. 【0031】 The second insulating layer may consist exclusively of a material that is substantially nonconductive and has a relative permeability of less than 1 or substantially equal to 1. Alternatively, the second insulating layer may substantially consist of a material that is substantially nonconductive and has a relative permeability of less than 1 or substantially equal to 1. The second insulating layer may include, for example, a laminated or composite structure, and therefore may consist of multiple layers and / or mixtures of particles / elements themselves. The layers or mixtures of particles / elements may consist of the same material or of one or more different materials selected from the group consisting of nonconductive materials, conductive materials and ferrimagnetic materials. It is understood that such combinations of materials can be provided in proportion to ensure that the second insulating layer "substantially" consists of a material that is substantially nonconductive and has a relative permeability of less than 1 or substantially equal to 1. 【0032】 In one embodiment, the second insulating layer may include a plastic material. The plastic material may include polyether-ether-ketone (PEEK) or any other material having extremely high thermal resistivity (insulator) and low thermal mass. It is understood that after a period of non-use of the steam generating device, the components of the device, and therefore the induction heating assembly, will cool to ambient temperature. During the initial startup of the steam generating device when heated steam comes into contact with the second insulating layer, condensation may form on the second insulating layer due to contact between the relatively hot steam and the cooler second insulating layer, and the condensation will remain until the temperature of the second insulating layer rises. The use of a material having extremely high thermal resistivity and low thermal mass minimizes condensation, ensuring that the second insulating layer warms up as quickly as possible following the initial startup of the device when heated steam comes into contact with the second insulating layer. 【0033】 The induction heating assembly may be configured to operate in a fluctuating electromagnetic field having a magnetic flux density of approximately 20 mT to approximately 2.0 T at its maximum concentration during use. 【0034】 The induction heating assembly may include a power supply and electrical circuitry that can be configured to operate at high frequencies. The power supply and electrical circuitry may be configured to operate at frequencies of approximately 80 kHz to 500 kHz, optionally approximately 150 kHz to 250 kHz, and optionally approximately 200 kHz. Depending on the type of induction-heatable susceptor used, the power supply and electrical circuitry may be configured to operate at even higher frequencies, for example, in the MHz range. 【0035】 The induction coil may include any suitable material, but typically it may include Litz wire or Litz cable. 【0036】 The induction heating assembly can take on any shape and form, but it may be arranged to take on a substantially induction coil shape in order to reduce excessive material use. The induction coil may also be substantially helical in shape. 【0037】 The circular cross-section of the helical induction coil facilitates the insertion of the induction-heatable cartridge into the induction heating assembly and ensures uniform heating of the induction-heatable cartridge. The resulting shape of the induction heating assembly is also comfortable for the user to hold. 【0038】 An induction-heatable cartridge may include one or more induction-heatable susceptors. Such or each susceptor may include, but are not limited to, one or more of aluminum, iron, nickel, stainless steel and their alloys, such as nickel-chromium or nickel-copper. When an electromagnetic field is applied nearby, such or each susceptor may generate heat due to eddy currents and magnetic hysteresis losses, thereby converting energy from the electromagnetic field into heat. 【0039】 An induction-heatable cartridge may contain a vapor-generating material inside a breathable shell. The breathable shell may contain an electrically insulating and non-magnetic breathable material. The material may have high breathability to allow air to flow through the material while withstanding high temperatures. Examples of suitable breathable materials include cellulose fibers, paper, cotton, and silk. The breathable material may also function as a filter. Alternatively, an induction-heatable cartridge may contain a vapor-generating material wrapped in paper. Alternatively, an induction-heatable cartridge may contain a vapor-generating material held inside a material that is not breathable but contains suitable holes or openings to allow air to flow. Alternatively, an induction-heatable cartridge may consist of the vapor-generating material itself. An induction-heatable cartridge may be formed in substantially the shape of a stick. 【0040】 The vapor-generating substance may be any type of solid or semi-solid material. Exemplary types of vapor-generating solids include powders, granules, pellets, pieces, strands, particles, gels, strips, loose leaves, shredded fillers, porous materials, foamed materials, or sheets. The substance may also include plant-derived materials, and in particular, the substance may include tobacco. 【0041】 The vapor-generating substance may contain an aerosol-forming agent. Examples of aerosol-forming agents include polyhydric alcohols and mixtures thereof, such as glycerin or propylene glycol. Typically, the vapor-generating substance may contain approximately 5% to approximately 50% aerosol-forming agent on a dry weight basis. In some embodiments, the vapor-generating substance may contain approximately 15% aerosol-forming agent on a dry weight basis. 【0042】 Furthermore, the vapor-generating substance may be the aerosol-forming agent itself. In this case, the vapor-generating substance may be a liquid. Also in this case, the induction-heatable cartridge may include a liquid-holding substance (e.g., a bundle of fibers, a porous material, e.g., ceramic) that holds the liquid in order to evaporate and allows vapor to be formed and released / radiated from the liquid-holding substance toward an air outlet, for example, for inhalation by the user. 【0043】 When heated, the vapor-generating substance may release volatile compounds. These volatile compounds may include nicotine or flavoring compounds, such as tobacco flavorings. 【0044】 Since the induction coil generates an electromagnetic field when operating to heat the susceptor, any component including the inductively heatable susceptor will be heated if placed in close proximity to the operating induction coil, and therefore the shape and form of the inductively heatable cartridge to be received in the heating compartment are not limited. In some embodiments, the inductively heatable cartridge may be cylindrical in shape, and therefore the heating compartment is arranged to receive a substantially cylindrical evaporable article. 【0045】 Since evaporable substances and tobacco products are often packaged and sold in cylindrical form, the ability of the heating compartment to receive substantially cylindrical induction-heatable cartridges to be heated is advantageous. [Brief explanation of the drawing] 【0046】 [Figure 1] This is a schematic diagram of a steam generation device including an induction heating assembly according to a first embodiment of the present disclosure. [Figure 2] This diagram shows the shielding effect obtained by using the electromagnetic shielding layer according to the embodiments of this disclosure and the variation in magnetic field strength obtained by using the insulating layer according to the embodiments of this disclosure. [Figure 3] This diagram shows the shielding effect obtained by using the electromagnetic shielding layer according to the embodiments of this disclosure and the variation in magnetic field strength obtained by using the insulating layer according to the embodiments of this disclosure. [Figure 4] This diagram shows the shielding effect obtained by using the electromagnetic shielding layer according to the embodiments of this disclosure and the variation in magnetic field strength obtained by using the insulating layer according to the embodiments of this disclosure. [Figure 5] This is a schematic diagram of a part of an induction heating assembly according to a second embodiment of the present disclosure. [Figure 6]This is a schematic diagram of a part of an induction heating assembly according to a third embodiment of the present disclosure. [Modes for carrying out the invention] 【0047】 Embodiments of the present disclosure are described herein by reference only as examples and with reference to the accompanying drawings. 【0048】 Referring first to Figure 1, a vapor generating device 10 according to an example of the present disclosure is schematically shown. The vapor generating device 10 includes a housing 12. When the device 10 is used to generate vapor to be inhaled, a mouthpiece 18 may be installed in the device 10 at an air outlet 19. The mouthpiece 18 provides the ability for the user to easily inhale the vapor generated by the device 10. The device 10 includes a power supply and control electrical circuit indicated by reference numeral 20, which may be configured to operate at a high frequency. The power supply typically includes one or more batteries, which may be inductively rechargeable, for example. The device 10 also includes an air inlet 21. 【0049】 The vapor generating device 10 includes an induction heating assembly 22 for heating a vapor-generating (i.e., evaporable) substance. The induction heating assembly 22 includes a substantially cylindrical heating compartment 24, which is arranged to receive a corresponding substantially cylindrical induction-heatable cartridge 26 containing an evaporable substance 28 and one or more induction-heatable susceptors 30. The induction-heatable cartridge 26 typically includes an outer layer or membrane to contain the evaporable substance 28, and the outer layer or membrane is permeable. For example, the induction-heatable cartridge 26 may be a disposable cartridge 26 containing a cigarette and at least one induction-heatable susceptor 30. 【0050】 The induction heating assembly 22 includes a helical induction coil 32 that extends around a cylindrical heating section 24 and can be excited by a power supply and control electrical circuit 20. As will be understood by those skilled in the art, when the induction coil 32 is excited, an alternating and time-varying electromagnetic field is created. This is coupled to one or more inductively heated susceptors 30 and generates eddy currents and / or hysteresis losses in the one or more inductively heated susceptors 30, thereby heating them. The heat is then transferred from one or more inductively heated susceptors 30 to an evaporable substance 28, for example, by conduction, radiation, and convection. 【0051】 The induction-heatable susceptor 30 may come into direct or indirect contact with the evaporable substance 28 so that heat is transferred from the susceptor 30 to the evaporable substance 28 when the susceptor 30 is induction-heated by the induction coil 32 of the induction heating assembly 22, in order to heat the evaporable substance 28 and generate vapor. The evaporation of the evaporable substance 28 is facilitated by the addition of air from the ambient environment through the air inlet 21. The vapor generated by the heating of the evaporable substance 28 then exits the heating compartment 24 through the air outlet 19 and can be inhaled by a user of the device 10, for example, through the mouthpiece 18. The airflow through the heating compartment 24, i.e., the airflow from the air inlet 21, through the heating compartment 24, along the intake passage 34 of the induction heating assembly 22, and exiting the air outlet 19, may be facilitated by negative pressure created by a user inhaling air using the mouthpiece 18 from the air outlet 19 side of the device 10. 【0052】 The induction heating assembly 22 includes a first electromagnetic shielding layer 36, which is positioned outside the induction coil 32 and is typically made of a ferrimagnetic, non-conductive material, such as ferrite, nickel-zinc ferrite, or mu-metal. In the embodiment shown in Figure 1, the first electromagnetic shielding layer 36 includes a substantially cylindrical shielding portion 38, for example, in the form of a substantially cylindrical sleeve, positioned radially outward of the helical induction coil 32 so as to extend circumferentially around the induction coil 32. The substantially cylindrical shielding portion 38 typically has a layer thickness (in the radial direction) of approximately 1.7 mm to 2 mm. The first electromagnetic shielding layer 36 also includes a first annular shielding portion 40 provided at the first axial end 14 of the induction heating assembly 22, having a layer thickness (in the axial direction) of approximately 5 mm. The first electromagnetic shielding layer 36 also includes a second annular shielding portion 42 provided at the second axial end 16 of the induction heating assembly 22. It should be noted that the second annular shield portion 42 comprises first and second layers 42a, 42b of the shielding material, between which an optional shielding coil 44 is positioned. In an alternative embodiment, the second annular shield portion 42 may comprise a single layer of the shielding material, either with or without the shielding coil 44. 【0053】 The induction heating assembly 22 includes a second electromagnetic shielding layer 46 positioned outside the first electromagnetic shielding layer 36. The second electromagnetic shielding layer 46 typically includes a conductive material, such as a metal like aluminum or copper, and may be in the form of a mesh. In the embodiment shown in Figure 1, the second electromagnetic shielding layer 46 includes a substantially cylindrical shielding portion 48 in the form of a substantially cylindrical sleeve with, for example, axially extending circumferential gaps (not shown), and an annular shielding portion 50 provided at the first axial end 14 of the induction heating assembly 22. The substantially cylindrical shielding portion 48 and the annular shielding portion 50 may be formed integrally as a single component. In some embodiments, the second electromagnetic shielding layer 46 has a layer thickness of approximately 0.15 mm. The resistance value of the second electromagnetic shielding layer 46 is selected to minimize heating and conductivity losses in the second electromagnetic shielding layer 46 and may have a value of, for example, less than 30 mΩ. 【0054】 The induction heating assembly 22 includes an outer housing layer 13 which surrounds the first and second electromagnetic shielding layers 36 and 46 and constitutes the outermost layer of the housing 12. In an alternative embodiment (not shown), the outer housing layer 13 may be omitted so that the second electromagnetic shielding layer 46 constitutes the outermost layer of the housing 12. 【0055】 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 nonconductive and has a relative permeability substantially equal to 1, and in the illustrated embodiment, the first insulating layer 52 contains air. 【0056】 Providing a first insulating layer 52 between the induction coil 32 and the first electromagnetic shielding layer 36 is advantageous in ensuring that an optimal electromagnetic field is generated for coupling with the susceptor 30 of the induction-heatable cartridge 26, which is schematically shown in Figures 2-4. For example, Figure 2 schematically shows the electromagnetic field generated by the helical induction coil 32 in the absence of the electromagnetic shielding layers 36, 46 described above. On the other hand, Figure 3 schematically shows the electromagnetic field generated by the helical induction coil 32 when the first electromagnetic shielding layer 36, in particular the substantially cylindrical shield portion 38, is positioned very close to the induction coil 32 or in contact with the induction coil 32, in other words, when the first insulating layer 52 is not provided. The first electromagnetic shielding layer 36 reduces the intensity of the electromagnetic field in the radially outer region of the first electromagnetic shielding layer 36, thereby reducing electromagnetic field leakage. However, as can be easily seen in Figure 3, this also reduces the intensity of the electromagnetic field in the radially inner region of the induction coil 32, to which the induction-heatable cartridge 26 is positioned when in use. This is undesirable because it adversely affects the electromagnetic field coupling between the induction-heatable cartridge 26 and the susceptor 30 and reduces heating efficiency. Finally, referring to Figure 4, it becomes clear that when the first insulating layer 52 according to an embodiment of the present disclosure is positioned between the induction coil 32 and the first electromagnetic shielding layer 36, the first electromagnetic shielding layer 36, particularly the substantially cylindrical shielding portion 38, reduces the intensity of the electromagnetic field in the radially outer region of the first electromagnetic shielding layer 36, thereby reducing electromagnetic field leakage in a manner similar to that shown in Figure 3. However, in contrast to Figure 3, the intensity of the electromagnetic field in the radially inward region of the induction coil 32 where the induction-heatable cartridge 26 is positioned during use does not decrease, thereby ensuring optimal coupling of the electromagnetic field between the induction-heatable cartridge 26 and the susceptor 30 and maximizing heating efficiency. 【0057】 Referring again to Figure 1, note that the induction heating assembly 22 includes an annular air passage 54 extending from the air inlet 21 to the heating section 24. The air passage 54 is located radially outward of 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. 【0058】 The induction heating assembly 22 further includes a second insulating layer 58. As can be seen in Figure 1, a first portion 58a of the second insulating layer 58 is positioned inside the induction coil 32, between the induction coil 32 and the evaporable material 28 inside the induction-heatable cartridge 26. A second portion 58b of the second insulating layer 58 is positioned outside the induction coil 32 and between the induction coil 32 and the first electromagnetic shielding layer 36, as can also be seen in Figure 1. In the illustrated embodiment, the second portion 58b includes a cylindrical sleeve 56 positioned adjacent to the first electromagnetic shielding layer 36 and radially outward from the annular air passage 54. The second insulating layer 58 is substantially nonconductive and has a relative magnetic permeability of less than 1 or substantially equal to 1, and typically includes a plastic material such as PEEK. As readily apparent from Figure 1, the first portion 58a of the second insulating layer 58 defines the internal volume of the heating compartment 24 into which the induction-heatable cartridge 26 is received during use. 【0059】 Referring now to Figure 5, a portion of a second embodiment of the induction heating assembly 60 for the steam generating device 10 is shown. The induction heating assembly 60 shown in Figure 5 is similar to the induction heating assembly 22 shown in Figure 1, and the corresponding components are identified using the same reference numerals. It should be noted that the substantially cylindrical shielding portions 38, 48 of the first and second electromagnetic shielding layers 36, 46 are omitted from Figure 5. 【0060】 The induction heating assembly 60 includes an intake passage 62 extending from the heating section 24 to the air outlet 19 at the first axial end 14 of the induction heating assembly 60. The intake passage 62 includes first and second axial portions 64, 66 extending substantially parallel to the axial direction between the heating section 24 and the air outlet 19. The intake passage 62 also includes a transverse portion 68 extending substantially perpendicular to the axial direction between the heating section 24 and the air outlet 19. Multiple electromagnetic shielding assemblies, each including first and second electromagnetic shielding layers 36, 46, are positioned to extend adjacently on both sides of the transverse portion 68 of the intake passage 62. In this arrangement, the electromagnetic shielding assemblies overlap at least partially with each other so that the first axial end of the induction coil 32 is substantially shielded by the electromagnetic shielding layers 36, 46. 【0061】 Referring now to Figure 6, a portion of a third embodiment of the induction heating assembly 70 for the steam generating device 10 is shown. The induction heating assembly 70 shown in Figure 6 is similar to the induction heating assembly 60 shown in Figure 5, and the corresponding components are identified using the same reference numerals. 【0062】 The induction heating assembly 70 includes an intake passage 72 extending from the heating section 24 to the air outlet 19 at the first axial end 14 of the induction heating assembly 70. The intake passage 72 includes first, second, third, and fourth axial portions 74, 76, 78, and 80 that extend substantially parallel to the axial direction between the heating section 24 and the air outlet 19. The intake passage 72 also includes first, second, and third transverse portions 82, 84, and 86 that extend substantially perpendicular to the axial direction between the heating section 24 and the air outlet 19. Multiple electromagnetic shielding assemblies, each including first and second electromagnetic shielding layers 36, and 46, are positioned, in this case as well, to extend adjacent to the transverse portions 82, 84, and 86 of the intake passage 72 on both sides of the transverse portion 84. In this arrangement, it is found that the electromagnetic shielding assemblies overlap at least partially with each other, in this case as well, so that the first axial end of the induction coil 32 is substantially shielded by the electromagnetic shielding layers 36, and 46. 【0063】 While exemplary embodiments have been described in the preceding paragraphs, it should be understood that these embodiments can be modified in various ways without departing from the scope of the attached claims. Therefore, the breadth and scope of the claims should not be limited to the exemplary embodiments described above. 【0064】 Unless the context clearly indicates otherwise, throughout the description and claims, terms such as “comprise” and “comprising” shall be interpreted in an inclusive sense, as opposed to an exclusive or exhaustive sense, that is, “includes but does not limit.”

Claims

[Claim 1] A steam generating device, wherein the steam generating device is A heating compartment positioned to receive an induction heating cartridge, An induction coil extending around the heating section, A first electromagnetic shielding layer is arranged on the outside of the induction coil, A first insulating layer positioned between the induction coil and the first electromagnetic shield layer, A second electromagnetic shielding layer is disposed on the outside of the first electromagnetic shielding layer, A second insulating layer that is nonconductive and has a relative magnetic permeability of less than 1 or substantially equal to 1, wherein the second insulating layer is made of a different material from the first insulating layer. Includes, The first and second electromagnetic shielding layers differ in their conductivity and / or their magnetic permeability. A portion of the second insulating layer is located between the induction coil and the evaporable substance inside the induction-heatable cartridge during use. A steam generating device in which the second electromagnetic shielding layer includes a substantially cylindrical shielding portion. [Claim 2] The vapor generating device according to claim 1, wherein one of the first and second electromagnetic shielding layers comprises a ferrimagnetic, non-conductive material, and the other of the first and second electromagnetic shielding layers comprises a conductive material. [Claim 3] The vapor generating device according to claim 1, wherein the first electromagnetic shielding layer comprises a ferrimagnetic, non-conductive material, and the second electromagnetic shielding layer comprises a conductive material. [Claim 4] The steam generating device according to claim 1, wherein the first electromagnetic shielding layer comprises a plurality of layers. [Claim 5] The vapor generating device according to claim 4, wherein the plurality of layers include one or more layers of ferrite and one or more layers of adhesive material. [Claim 6] The steam generating device according to claim 1, wherein the first electromagnetic shielding layer has a thickness of 0.1 mm to 10 mm. [Claim 7] The steam generating device according to claim 1, wherein the first electromagnetic shielding layer has a thickness of 0.1 mm to 0.7 mm. [Claim 8] The steam generating device according to claim 1, wherein the second electromagnetic shielding layer has a thickness of 0.1 mm to 0.5 mm. [Claim 9] The steam generating device according to claim 1, wherein the second electromagnetic shielding layer has a resistance value of less than 30 mΩ. [Claim 10] The steam generating device according to claim 1, wherein the second electromagnetic shielding layer includes a substantially cylindrical sleeve. [Claim 11] The steam generating device according to claim 1, wherein there is no conductive material between the induction coil and the first electromagnetic shielding layer. [Claim 12] The steam generating device according to claim 1, wherein the second electromagnetic shielding layer is the outermost layer of the steam generating device. [Claim 13] The steam generating device according to claim 1, further comprising an outer housing layer surrounding the first and second electromagnetic shielding layers. [Claim 14] The steam generating device according to claim 1, wherein the second insulating layer includes a plastic material. [Claim 15] The steam generating device according to claim 1, further comprising a power supply and an electrical circuit, wherein the power supply and the electrical circuit are configured to operate in a range of MHz units. [Claim 16] A system, wherein the system A steam generating device according to claim 1, A disposable cartridge containing an evaporable substance and one or more susceptors. Includes, A system in which, when in use, the disposable cartridge is removably received in the heating section of the steam generating device. [Claim 17] The system according to claim 16, wherein the disposable cartridge is in the shape of a stick.