A composite wire structure for induction heating

Abstract

This utility model relates to the field of induction heating and discloses a composite filament structure for induction heating, comprising a core material and a covering layer tightly surrounding the core material. The covering layer includes an induction heating layer. The core material includes a temperature feedback material with a Curie temperature below 550°C. The composite filament has an axisymmetric or centrosymmetric structure. The axisymmetric or centrosymmetric structure offsets the stress caused by the difference in thermal expansion of different materials in the composite filament, ensuring that the composite filament only experiences symmetrical internal stress changes, at least within the operating temperature range, resulting in minimal overall thermal deformation. The operating temperature range extends from 50K below the Curie temperature of the temperature feedback material to the Curie temperature of the temperature feedback material. This application makes the temperature distribution of the aerosol-forming matrix more uniform. It can mutually offset certain thermal stress deformations, avoiding undesirable deformation of the composite filament.

Description

Technical Field

[0001] This utility model relates to the technical field of induction heating, and in particular to a composite wire structure for induction heating. Background Technology

[0002] In recent years, a novel aerosol generation method based on induction heating has emerged. Its basic structure and principle involve placing a solenoid outside the aerosol generator cavity and embedding a metallic magnetic inductor within the aerosol generation matrix. During operation, an alternating current excites the solenoid, generating a rapidly changing alternating magnetic field. The metallic magnetic inductor embedded in the aerosol generation matrix generates a corresponding magnetic field within this field. The magnetic domains within the metallic magnetic inductor rotate at high speed, generating corresponding eddy current losses and hysteresis losses. The heat generated by these eddy current and hysteresis losses heats the adjacent aerosol generation matrix, thereby producing aerosols.

[0003] Embedding a metallic magnetic inductor in an induction-heated aerosol generating matrix is ​​a heating method that heats the aerosol generating matrix from the inside. Heating from the center of the aerosol generating matrix does not cause oxidation or combustion, leaves no combustion residue, requires no cleaning, and avoids problems such as heater damage.

[0004] To control the temperature of the substrate, existing patents propose a bilayer induction heating sheet material comprising first and second layers made of two different materials. The first induction heating material is optimized for heating efficiency and typically has a high Curie temperature. In contrast, the second induction heating material is used as a temperature feedback element. For this purpose, the second induction heating material has a lower Curie temperature than the first induction heating material. At its Curie temperature, the permeability of the second induction heating material decreases by an order of magnitude, causing its magnetism to change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output of the induction power supply, it is possible to detect whether the second induction heating material has reached its Curie temperature, and feedback control can be used to operate it at a predefined heating temperature.

[0005] While this double-layer induction heating material offers good controllability of heating temperature, it has two significant drawbacks: 1. The limited contact area between the sheet material and the aerosol-forming matrix results in uneven temperature distribution within the aerosol-forming matrix. Specifically, the temperature of the aerosol-forming matrix near the sheet material is higher, while the temperature further away is lower. 2. Undesirable deformation can occur during or after use due to the double-layer metal structure. Utility Model Content

[0006] The purpose of this invention is to provide a composite filament structure for induction heating, aiming to solve the above-mentioned defects in the prior art.

[0007] This application provides a composite filament structure for induction heating, comprising a core material and a covering layer tightly surrounding the core material. The covering layer includes an induction heating layer. The core material includes a temperature feedback material having a Curie temperature below 550°C. The composite filament is an axisymmetric or centrosymmetric structure. The axisymmetric or centrosymmetric structure offsets the stress caused by the difference in thermal expansion of different materials in the composite filament, such that, at least within the operating temperature range, the composite filament only experiences symmetrical internal stress changes, resulting in small overall thermal deformation. The operating temperature range extends from at least 50K below the Curie temperature of the temperature feedback material to the Curie temperature of the temperature feedback material. The core material has a Curie temperature between 150°C and 550°C.

[0008] Furthermore, the covering layer is multi-layered, one or more of which are leak-proof layers, and the leak-proof layers are made of thermally conductive non-metallic materials.

[0009] Furthermore, the induction heating layer is used to induction heat the aerosol forming matrix, and the Curie temperature of the core material's temperature feedback material corresponds to the predefined heating temperature of the composite filament.

[0010] Furthermore, the cross-sections of the core material and the cladding layer have an axisymmetric or centrosymmetric shape.

[0011] Furthermore, the cross-sections of the core material and the covering layer are rectangular or concentric circles.

[0012] Furthermore, the induction heating layer also has a Curie temperature, the Curie temperature of the core material is a first Curie temperature, and the Curie temperature of the induction heating layer is a second Curie temperature, which is higher than the first Curie temperature.

[0013] Furthermore, when the coating layer is multi-layered, each coating layer may have a different Curie temperature than the others.

[0014] Furthermore, the induction heating layer is mainly used to heat the aerosol forming matrix, and the induction heating layer has a Curie temperature of over 600°C.

[0015] Furthermore, the induction heating layer comprises one or more of ferromagnetic metals, paramagnetic metals, and ferrimagnetic materials, so that heat can be generated not only through eddy currents but also through hysteresis losses.

[0016] Compared to existing technologies, this application optimizes the heating efficiency of the induction heating layer, typically achieving a higher Curie temperature. The core material serves as a temperature feedback layer. The core material has a Curie temperature below 550°C. At its Curie temperature, the permeability of the core material decreases by an order of magnitude, causing its magnetism to change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it is possible to detect whether the core material has reached its Curie temperature. Feedback control ensures the composite filament operates at a predefined heating temperature for the core material. Because the composite filament in this application is configured such that the induction heating layer tightly surrounds the core material, the contact area between the induction heating layer and the aerosol-forming matrix is ​​large during heating, resulting in a more uniform temperature distribution within the aerosol-forming matrix. Furthermore, since the induction heating layer tightly surrounds the core material and the composite filament has an axisymmetric or centrosymmetric structure, it can mutually offset certain thermal stress deformations during or after material use, preventing undesirable deformation of the composite filament. Attached Figure Description

[0017] Figure 1 This is an exploded view of a composite filament structure for induction heating provided in an embodiment of this utility model;

[0018] Figure 2 This is a schematic diagram of a composite wire structure for induction heating provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram illustrating the application of a composite wire structure for induction heating provided in an embodiment of this utility model. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0025] The implementation of this utility model will be described in detail below with reference to specific embodiments.

[0026] Reference Figure 1-3 A composite filament structure for induction heating includes a core material and a covering layer tightly surrounding the core material. The covering layer includes an induction heating layer. The core material includes a temperature feedback material having a Curie temperature below 550°C. The composite filament is an axisymmetric or centrosymmetric structure. The axisymmetric or centrosymmetric structure offsets the stress caused by the difference in thermal expansion of different materials in the composite filament, so that the composite filament only produces symmetrical internal stress changes, with small overall thermal deformation, at least within the operating temperature range. The operating temperature range extends from at least 50K below the Curie temperature of the temperature feedback material to the Curie temperature of the temperature feedback material. The core material has a Curie temperature between 150°C and 550°C.

[0027] According to this invention, we can see that existing multilayer induction heating materials may deform at different temperatures due to the inherent differences in the coefficients of linear expansion between the various layer materials. For example, the processing of existing double-layer induction heating materials may involve tightly bonding the two layers together at a given temperature. After bonding the layers, the multilayer induction heating material may undergo heat treatment, such as annealing. During temperature changes, such as during the cooling of the multilayer induction heating material, the layers cannot deform freely due to the tight bond between them. Therefore, due to the different coefficients of linear expansion, one layer may exert internal stress on another layer, especially on adjacent layers. This uneven internal stress causes deformation, particularly surface bending of the multilayer induction heating material.

[0028] To address this issue, the composite induction heating wire according to this invention has an axisymmetric or centrosymmetric structure. Due to the symmetrical structure of the composite wire, the differences in thermal expansion between the different materials within the composite induction heating wire are compensated, ensuring that, at least within the operating temperature range, the composite induction heating wire only experiences symmetrical internal stress changes while the overall thermal deformation is almost zero. The operating temperature range extends from at least 50K below the Curie temperature of the temperature feedback material to the Curie temperature of the temperature feedback material.

[0029] In this application, the induction heating layer is optimized for heating efficiency and typically has a high Curie temperature. The core material is used as a temperature feedback layer. The core material has a Curie temperature below 550°C. At its Curie temperature, the permeability of the core material drops by an order of magnitude, causing its magnetism to change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it is possible to detect whether the core material has reached its Curie temperature, and feedback control allows the composite filament to operate at a predefined heating temperature for the core material. Because the composite filament in this application is configured such that the induction heating layer tightly surrounds the core material, the contact area between the induction heating layer and the aerosol-forming matrix is ​​large during heating, resulting in a more uniform temperature distribution in the aerosol-forming matrix. Simultaneously, because the induction heating layer tightly surrounds the core material and the composite filament has an axisymmetric or centrosymmetric structure, it can mutually offset certain thermal stress deformations during or after material use, preventing undesirable deformation of the composite filament.

[0030] Because the core material has a Curie temperature between 150°C and 550°C. Curie temperature and temperature feedback are the main properties of the core material, but its electrical conductivity can also help with heating.

[0031] As used herein, the term 'tightly wrapped' refers to a mechanical connection, or more specifically a metallurgical bond, between two layers within a multilayer assembly, enabling reliable stress transfer between the core and cladding layers, and among multiple cladding layers, particularly in directions parallel to the axis. The connection can be two-dimensional or three-dimensional; specifically, two tightly wrapped layers may be in direct contact with each other. Alternatively, the connection can be indirect, via other media. Specifically, the two layers may be indirectly connected via at least one intermediate layer.

[0032] Preferably, the core material comprises a ferromagnetic metal, such as nickel (Ni) and its alloys. Depending on the properties of the alloying elements, the Curie temperature of nickel alloys is in the range of about 260°C to 450°C. This range of Curie temperatures is ideal because it is approximately the same temperature at which heating should be performed to generate aerosols from the aerosol-forming matrix, but still low enough to avoid localized overheating or combustion of the aerosol-forming matrix.

[0033] In practical applications, composite filaments can exhibit different application forms depending on the properties of the aerosol-forming matrix. Specifically, when the aerosol-forming matrix is ​​a sheet-like material, the composite filaments can be evenly distributed throughout the entire aerosol-forming matrix in bundles. Alternatively, the composite filaments can be woven into mesh or columnar mesh and placed in the aerosol-forming matrix. They can also be woven into a mesh and wound together with the aerosol-forming matrix, evenly distributed within it. When the aerosol-forming matrix is ​​granular or a viscous paste, the composite filaments can be cut into short fibers and evenly dispersed within the aerosol-forming matrix.

[0034] Preferably, in practical applications, the composite filament can be used in combination with other filaments, including but not limited to metal filaments, non-metal filaments, and composite filaments.

[0035] In one embodiment, the covering layer is multi-layered, with one or more layers serving as leak-proof layers made of a thermally conductive non-metallic material. Since the core material may be made of nickel (Ni) or its alloys, nickel (Ni) and its alloys release nickel during heating, which can pollute the environment and is detrimental to environmental protection. The leak-proof layer helps to prevent the release of nickel. Furthermore, the way the covering layer surrounds and encloses the core material in this application further enhances the effectiveness of preventing nickel leakage and is more environmentally friendly.

[0036] Furthermore, the induction heating layer is used to induction heat the aerosol forming matrix, and the Curie temperature of the core material's temperature feedback material corresponds to the predefined heating temperature of the composite filament.

[0037] Preferably, the cross-sections of the core material and the cladding layer have an axisymmetric or centrosymmetric shape.

[0038] More preferably, the cross-sections of the core material and the covering layer are rectangular or concentric circles.

[0039] Furthermore, the induction heating layer also has a Curie temperature. The Curie temperature of the core material is a first Curie temperature, and the Curie temperature of the induction heating layer is a second Curie temperature, which is higher than the first Curie temperature. The Curie temperature of the induction heating layer is different from, and especially higher than, the Curie temperature of the core material. When the heating temperature of the core material is higher than its Curie temperature, the ferrimagnetic or ferromagnetic material of the core material will lose its ferrimagnetism or ferromagnetism and become paramagnetic, respectively.

[0040] Furthermore, when the coating layer is multi-layered, each coating layer can also have a different Curie temperature than the others. The composite filament can provide a variety of functionalities, such as induction heating and controlled heating temperature. Specifically, these functionalities can provide at least two preset operating temperatures due to the presence of at least two different Curie temperatures.

[0041] Furthermore, the induction heating layer is primarily used for heating the aerosol forming matrix, and the induction heating layer has a Curie temperature exceeding 600°C. The induction heating layer is enhanced in terms of eddy current and / or hysteresis losses, and therefore optimized in terms of heating efficiency.

[0042] Furthermore, the induction heating layer comprises one or more of ferromagnetic metals, paramagnetic metals, and ferrimagnetic materials, thus generating heat not only through eddy currents but also through hysteresis losses. In this case, heat can be generated not only through eddy currents but also through hysteresis losses. Preferably, the induction heating layer comprises iron (Fe) or an iron alloy, such as steel or an iron-nickel alloy. Specifically, the induction heating layer may comprise stainless steel, such as ferritic stainless steel or martensitic stainless steel. In particular, the induction heating layer comprises 400 series stainless steel, such as 410 stainless steel, or 420 stainless steel, or 430 stainless steel, or similar stainless steel.

[0043] Figure 1 and Figure 2 The schematic diagram illustrates an exemplary embodiment of the composite induction heating wire according to this utility model. The following will discuss... Figure 3 To explain in more detail, the composite filament is embedded in the aerosol-generating article, in direct contact with the aerosol-forming matrix to be heated. The article itself is suitable for placement within an aerosol-generating device, which includes an induction source for generating an alternating magnetic field, particularly a high-frequency magnetic field. The alternating magnetic field generates eddy currents and / or hysteresis losses within the composite induction heating material, thereby heating the composite induction heating filament. The position of the composite induction heating filament within the aerosol-generating article and the position of the aerosol-generating article within the aerosol-generating device ensures that the composite induction heating filament is precisely positioned within the alternating magnetic field generated by the induction source.

[0044] according to Figure 1 and Figure 2 The composite induction heating wire of the illustrated embodiment is a wire having a core and a cladding layer. The composite induction heating wire includes a cladding layer that serves as a heat source, and this cladding layer is enhanced in terms of eddy current and / or hysteresis losses, thus optimizing heating efficiency. In the current embodiment, the substrate comprises ferromagnetic stainless steel with a Curie temperature exceeding 600°C. To control the heating temperature, the composite wire includes a core material disposed within the cladding layer and tightly connected to the middle or functional layer of the cladding layer. In the current embodiment, the core material is a nickel alloy with a Curie temperature ranging from approximately 260°C to 450°C. This Curie temperature is advantageous for temperature control and controlled heating of the aerosol-forming matrix. During heating, as the cladding layer reaches the Curie temperature of the nickel alloy, the magnetic properties of the core material change from ferromagnetic to paramagnetic, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it is possible to detect whether the induction heating material of the cladding layer has reached its Curie temperature, and feedback control can be used to operate it at a predefined heating temperature of the core material.

[0045] about Figure 1 and Figure 2 In the embodiment shown, the composite induction heating wire consists of a 1J50 core material 1 and a 430 cladding layer 2. The wire length L is 11 mm, and the cladding layer A is 20 μm while the core material B is 10 μm. The wire is drawn from a 430 seamless tube covering a 1J50 bar stock, and has an outer diameter of 60 μm.

[0046] Figure 3 An exemplary embodiment of the composite induction heating material according to the present invention is schematically shown. The heated non-combustible moxibustion product includes three elements arranged in series: an aerosol generating matrix, an aerosol cooling element, and an aerosol aggregating element. The aerosol generating matrix and the aerosol cooling element are generally cylindrical and each has substantially the same diameter. The aerosol aggregating element is an umbrella-shaped element. The three elements are arranged sequentially. The composite induction heating filament is located within the aerosol generating matrix, distributed in a bundle and in close contact with the aerosol generating matrix. The composite induction heating filament has a length substantially the same as that of the aerosol generating matrix, and the axis of the composite induction heating filament is almost parallel to the axis of the aerosol generating matrix. The aerosol generating matrix comprises an aggregated flocculent material of homogenized moxa wool surrounded by packaging material.

[0047] Figure 3The illustrated heat-not-burning moxibustion product is designed to be combined with an induction heating device. The induction heating device may include an induction source having an induction coil or inductor for generating an alternating, particularly high-frequency, electromagnetic field. After the heat-not-burning moxibustion product is combined with the induction heating device, the composite induction heating wire of the heat-not-burning moxibustion product is positioned within the electromagnetic field. The aerosol generated by heating flows into an aerosol collecting element after being cooled by an aerosol cooling element, thereby acting on the human skin.

[0048] The specific applications of composite induction heating wire include, but are not limited to, heat-not-burning products such as aromatherapy diffusers and electric mosquito coils.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite wire structure for induction heating, characterized by, The composite material comprises a core material and a covering layer tightly surrounding the core material. The covering layer includes an induction heating layer. The core material includes a temperature feedback material having a Curie temperature below 550 °C. The composite filament has an axisymmetric or centrosymmetric structure. The axisymmetric or centrosymmetric structure offsets the stress caused by the difference in thermal expansion of different materials in the composite filament, so that the composite filament only produces symmetrical internal stress changes, with small overall thermal deformation, at least within the operating temperature range. The operating temperature range extends from at least 50 K below the Curie temperature of the temperature feedback material to the Curie temperature of the temperature feedback material. The core material has a Curie temperature between 150 °C and 550 °C.

2. A composite wire structure for induction heating according to claim 1, characterized in that, The covering layer is multi-layered, one or more of which are leak-proof layers, and the leak-proof layers are made of thermally conductive metal materials or thermally conductive non-metal materials.

3. A composite wire structure for induction heating according to claim 1, wherein The induction heating layer is used to induction heat the aerosol to form a matrix, and the Curie temperature of the core material corresponds to the predefined heating temperature of the composite filament.

4. An induction heating composite wire structure according to claim 1, wherein The cross-sections of the core material and the cladding layer are axially symmetric or centrally symmetric.

5. An induction heating composite wire structure according to claim 4, wherein The cross-sections of the core material and the cladding layer are rectangular or concentric circles.

6. An induction heating composite wire structure according to claim 1, wherein The induction heating layer also has a Curie temperature. The Curie temperature of the core material is a first Curie temperature, and the Curie temperature of the induction heating layer is a second Curie temperature, which is higher than the first Curie temperature.

7. An induction heatable composite wire structure according to claim 2, characterized in that When the coating layer is multi-layered, each coating layer may also have a Curie temperature different from the others.

8. An induction heating composite wire structure according to claim 1, wherein The induction heating layer is mainly used to heat the aerosol forming matrix, and the induction heating layer has a Curie temperature of over 600°C.

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