Composite wire for induction heating of aerosol-forming substrate

Abstract

The present invention relates to the field of induction heating, and discloses a composite wire for induction heating of an aerosol-forming substrate, comprising a core material and a cladding layer disposed closely around the core material, the cladding layer comprising an induction heating layer, the core material comprising a temperature feedback material having a Curie temperature of less than 550 DEG C, the composite wire is of an axial symmetry structure or a central symmetry structure. The axial symmetry structure or the central symmetry structure counteracts stress generated by thermal expansion differences of different materials in the composite wire, so that the composite wire only generates symmetrical internal stress changes at least within the working temperature range, and the overall thermal deformation is small; the operating temperature range is at least 50 K lower than the Curie temperature of the temperature feedback material and extends to the Curie temperature of the temperature feedback material. According to the invention, the temperature distribution of the aerosol-forming substrate is more uniform. Certain thermal stress deformation can be offset mutually, and unexpected deformation of the composite wire is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of induction heating, and in particular to a composite wire material for induction heating aerosol forming matrix. Background Art

[0002] In recent years, a new type of aerosol generation method of a heat-not-burn aerosol generating device based on induction heating has been developed. Its basic structure and principle are to place a solenoid outside the cavity of the aerosol generating device and embed a metal magnetic induction body in the aerosol generating matrix. When working, the alternating current excites the solenoid, generating a high-speed changing alternating magnetic field in the solenoid, and the metal magnetic induction body embedded in the aerosol generating matrix generates a corresponding magnetic field in the magnetic field. The magnetic domains in the metal magnetic induction body rotate at a high speed, generating corresponding eddy current loss and hysteresis loss. The heat energy generated by the eddy current loss and hysteresis loss is used to heat the adjacent aerosol generating matrix to generate aerosol.

[0003] Embedding a metal magnetic induction body in the induction heating aerosol generating matrix is ​​a heating method that heats the aerosol generating matrix from the inside. It heats from the center of the aerosol generating matrix without oxidative combustion, leaving no combustion residue, requiring no cleaning, and without problems such as heater damage.

[0004] In order to control the temperature of the substrate, the existing patent proposes a double-layer induction heating sheet material including a first and a second layer made of two materials respectively. The first layer of induction heating material is optimized in terms of heating efficiency and usually has a higher Curie temperature. In contrast, the second layer of induction heating material is used as a temperature feedback element. To this end, the second layer of induction heating material has a Curie temperature lower than that of the first layer of induction heating material. At its Curie temperature, the magnetic permeability of the second layer of induction heating material drops by an order of magnitude, causing its magnetism to change from ferromagnetism or ferrimagnetism to paramagnetism, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it can be detected whether the second layer of induction heating material has reached its Curie temperature, and feedback control is used to make it operate at the predefined heating temperature of the second layer of induction heating material.

[0005] Although this double-layer induction heating material provides good controllability of the heating temperature, it has two obvious disadvantages: 1. The contact area between the sheet material and the aerosol-forming substrate is limited, resulting in an uneven temperature distribution of the aerosol-forming substrate. That is, the temperature of the aerosol-forming substrate close to the sheet material is higher, while the temperature of the aerosol-forming substrate away from the sheet material is lower. 2. Undesirable deformation occurs during or after use of the material due to the double-layer metal structure. Summary of the invention

[0006] The object of the present invention is to provide a composite wire material for induction heating aerosol forming substrate, aiming to solve the above-mentioned defects in the prior art.

[0007] The present application provides a composite wire material for induction heating of an aerosol-forming substrate, comprising a core material and a cladding layer tightly arranged around the core material, the cladding layer comprising an induction heating layer, the core material comprising a temperature feedback material having a Curie temperature lower than 550°C, and the composite wire material being an axisymmetric structure or a centrosymmetric structure; the axisymmetric structure or the centrosymmetric structure offsets the stress generated by the difference in thermal expansion of different materials in the composite wire material, so that at least within the operating temperature range, the composite wire material only generates symmetrical internal stress changes and has small overall thermal deformation; the operating temperature range is at least 50K lower than the Curie temperature of the temperature feedback material and extends to the Curie temperature of the temperature feedback material.

[0008] Furthermore, the coating layer is a multi-layer layer, wherein one or more layers are anti-leakage layers, and the anti-leakage layers are made of metal materials or non-metal materials.

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

[0010] Furthermore, the cross-sections of the core material and the cladding layer are axially symmetrical or centrally symmetrical.

[0011] Furthermore, the cross-sections of the core material and the cladding 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, the Curie temperature of the induction heating layer is a second Curie temperature, and the second Curie temperature is higher than the first Curie temperature.

[0013] Furthermore, when the coating layer is a multilayer, each coating layer may have a Curie temperature different from each other.

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

[0015] Furthermore, the induction heating layer includes one or more of ferromagnetic metal, paramagnetic metal and ferrimagnetic material, so that heat can be generated not only by eddy current but also by hysteresis loss.

[0016] Furthermore, the core material has a Curie temperature between 150°C and 550°C.

[0017] Compared with the prior art, in the present application, the induction heating layer is optimized in terms of heating efficiency and generally has a higher Curie temperature. The core material is used as a temperature feedback layer. The material of the core material has a Curie temperature below 550 ° C. At its Curie temperature, the magnetic permeability of the core material drops to an order of magnitude, causing its magnetism to change from ferromagnetism or ferrimagnetism to paramagnetism, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it can be detected whether the core material has reached its Curie temperature, and the composite wire material is operated at the predefined heating temperature of the core material through feedback control. The composite wire material of the present application is arranged so that the induction heating layer is closely arranged around the core material, and the contact area between the induction heating layer and the aerosol forming matrix during heating is large, so that the temperature distribution of the aerosol forming matrix is ​​more uniform. At the same time, since the induction heating layer is closely arranged around the core material and the composite wire material is an axisymmetric structure or a centrosymmetric structure, during or after the use of the material, certain thermal stress deformations can be offset each other, avoiding undesirable deformation of the composite wire material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a schematic diagram of the structural decomposition of a composite wire material for induction heating aerosol forming a matrix provided by an embodiment of the present invention; Figure 2 1 is a schematic structural diagram of a composite wire material for induction heating aerosol forming a matrix provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the application of a composite wire material for induction heating aerosol forming matrix provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0024] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0025] Reference Figures 1 to 3 , a composite wire material for induction heating of an aerosol-forming substrate, comprising a core material and a coating layer tightly arranged around the core material, the coating layer comprising an induction heating layer, the core material comprising a temperature feedback material having a Curie temperature lower than 550°C, the composite wire material being an axisymmetric structure or a centrosymmetric structure; the axisymmetric structure or the centrosymmetric structure offsets the stress generated by the difference in thermal expansion of different materials in the composite wire material, so that the composite wire material only generates symmetrical internal stress changes within the working temperature range, and the overall thermal deformation is small; the working temperature range is at least 50K lower than the Curie temperature of the temperature feedback material and extends to the Curie temperature of the temperature feedback material.

[0026] According to the present invention, it can be found that at different temperatures, existing multilayer induction heating materials may cause deformation due to the inherent differences between the linear expansion coefficients of the various layer materials. For example, the treatment of existing double-layer induction heating materials can be to tightly connect the two layer materials to each other at a given temperature. After connecting the layers, the multilayer induction heating material may be subjected to a heat treatment, such as annealing. During temperature changes, such as during cooling of the multilayer induction heating material, the layers cannot deform freely due to the tight connection between the layers. Therefore, due to different linear expansion coefficients, one layer may exert internal stress on another layer, especially on adjacent layers. Deformation, especially surface bending of the multilayer induction heating material, occurs due to the uneven internal stress on the material.

[0027] In order to solve this situation, the composite induction heating wire according to the present invention has an axisymmetric or centrosymmetric structure. Due to the symmetrical structure of the composite wire, the thermal expansion difference of different materials in the composite induction heating wire is compensated, so that at least within the working temperature range, the composite induction heating wire only produces symmetrical internal stress changes and the overall thermal deformation is almost zero. The working temperature range is at least 50K lower than the Curie temperature of the temperature feedback material and extends to the Curie temperature of the temperature feedback material.

[0028] In the present application, the induction heating layer is optimized in terms of heating efficiency and generally has a higher Curie temperature. The core material is used as a temperature feedback layer. The material of the core material has a Curie temperature below 550 ° C. At its Curie temperature, the magnetic permeability of the core material drops to an order of magnitude, causing its magnetism to change from ferromagnetism or ferrimagnetism to paramagnetism, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it can be detected whether the core material has reached its Curie temperature, and the composite wire material is operated at the predefined heating temperature of the core material through feedback control. The composite wire material of the present application is arranged so that the induction heating layer is closely arranged around the core material, and the contact area between the induction heating layer and the aerosol forming matrix during heating is large, so that the temperature distribution of the aerosol forming matrix is ​​more uniform. At the same time, since the induction heating layer is closely arranged around the core material and the composite wire material is an axisymmetric structure or a centrosymmetric structure, during or after the use of the material, certain thermal stress deformations can be offset each other, avoiding undesirable deformation of the composite wire material.

[0029] As used herein, the term 'closely surrounding' refers to a mechanical connection or further metallurgical connection between two layers in a multilayer assembly, so that stress can be reliably transferred between the core material and the cladding layer and between multiple cladding layers, especially in a direction parallel to the axis. The connection can be a two-dimensional or three-dimensional connection. Specifically, the two layers that are closely connected to each other can be in direct contact with each other. Or the connection can be an indirect connection through other media. Specifically, the two layers can be indirectly connected through at least one intermediate layer.

[0030] Preferably, the core material comprises a ferromagnetic metal, such as nickel (Ni) and its alloys. Depending on the nature of the alloying elements, the Curie temperature of nickel alloys is in the range of about 260° C. to 450° C. respectively. Curie temperatures in this range are ideal because they are approximately the same as the temperature to which the aerosol-forming substrate should be heated in order to generate an aerosol, but are still low enough to avoid local overheating or burning of the aerosol-forming substrate.

[0031] In specific applications, the composite wire material can present different application forms according to the properties of different aerosol-forming substrates. Specifically, when the aerosol-forming substrate is a sheet material, the composite wire material can be evenly distributed in the entire aerosol-forming substrate in a bundle. Or the composite wire material can be woven into a mesh belt or a columnar mesh and placed in the aerosol-forming substrate. It can also be woven into a mesh and wound together with the aerosol-forming substrate and evenly distributed in the aerosol-forming substrate. When the aerosol-forming substrate is granular or viscous paste, the composite wire material can be cut into short fibers and evenly dispersed in the aerosol-forming substrate.

[0032] Preferably, in actual application of the above application form, the composite wire material can be mixed with other wire materials for use, and the other wire materials include but are not limited to metal wires, non-metal wires and composite material wires.

[0033] In one embodiment, the coating layer is multi-layered, one or more of which is a leakage-proof layer, and the leakage-proof layer is made of a metal material or a non-metallic material. Since the core material may be made of nickel (Ni) and its alloys, nickel (Ni) and its alloys will release nickel during the heating process, which will pollute the environment and is not conducive to environmental protection. The provision of the leakage-proof layer is conducive to preventing the release of nickel. At the same time, due to the setting method of the coating layer of the present application surrounding and wrapping the core material, the effect of preventing nickel leakage is better and more environmentally friendly.

[0034] Furthermore, the induction heating layer is used for induction heating of the aerosol-forming matrix, and the Curie temperature of the temperature feedback material of the core material corresponds to the predefined heating temperature of the composite filament.

[0035] Preferably, the cross-sections of the core material and the cladding layer are axially symmetrical or centrally symmetrical.

[0036] Further preferably, the cross-sections of the core material and the cladding layer are rectangular or concentric circles.

[0037] Further, the induction heating layer also has a Curie temperature, the Curie temperature of the core material is a first Curie temperature, the Curie temperature of the induction heating layer is a second Curie temperature, and the second Curie temperature is higher than the first Curie temperature. The Curie temperature of the induction heating layer is different from, and in particular, higher than, the Curie temperature of the core material. When the core material heating temperature is higher than the Curie temperature of the core material, the ferrimagnetic or ferromagnetic material of the core material will lose its ferrimagnetism or ferromagnetism respectively and become paramagnetic.

[0038] Furthermore, when the coating layer is multi-layer, each coating layer may have a Curie temperature different from each other. The composite wire can provide multiple functionalities, such as induction heating and control of heating temperature. Specifically, these functionalities can provide at least two preset working temperatures due to the presence of at least two different Curie temperatures.

[0039] Further, the induction heating layer is mainly used to heat the aerosol-forming substrate, and the induction heating layer has a Curie temperature of more than 600° C. The induction heating layer is enhanced in terms of eddy current and / or hysteresis loss and thus optimized in terms of heating efficiency.

[0040] Further, the induction heating layer includes one or more of ferromagnetic metal, paramagnetic metal and ferrimagnetic material, so that heat can be generated not only by eddy current but also by hysteresis loss. In this case, heat can be generated not only by eddy current but also by hysteresis loss. Preferably, the induction heating layer includes iron (Fe) or an iron alloy, such as steel or an iron-nickel alloy. Specifically, the induction heating layer may include stainless steel, such as ferritic stainless steel or martensitic stainless steel. In particular, the induction heating layer includes 400 series stainless steel, such as 410 stainless steel, or 420 stainless steel, or 430 stainless steel or similar stainless steel.

[0041] Further, the core material has a Curie temperature between 150° C. and 550° C. The Curie temperature and the temperature feedback function are the main properties of the core material, but its electrical conductivity can also contribute to heating.

[0042] Figure 1 and Figure 2 The schematic diagram is an exemplary embodiment of the composite induction heating wire according to the present invention. Figure 3Explaining in more detail, the composite filament is embedded in the aerosol generating article, in direct contact with the aerosol-forming substrate to be heated. The article itself is suitable for being placed in an aerosol generating device, which includes an induction source for generating an alternating magnetic field, especially a high-frequency magnetic field. The alternating magnetic field generates eddy currents and / or hysteresis losses in the composite induction heating material, thereby heating the composite induction heating filament. The position of the composite induction heating filament in the aerosol generating article and the position of the aerosol generating article in the aerosol generating device are such that the composite induction heating filament is accurately positioned within the alternating magnetic field generated by the induction source.

[0043] according to Figure 1 and Figure 2 The composite induction heating wire of the illustrated embodiment is a wire having a core material and a coating layer. The composite induction heating wire includes a coating layer as a heating source, which is enhanced in terms of eddy current and / or hysteresis loss and is therefore optimized in terms of heating efficiency. In the current embodiment, the substrate includes a ferromagnetic stainless steel with a Curie temperature exceeding 600°C. To control the heating temperature, the composite wire includes a core material, which is arranged inside the coating layer and is closely connected to the intermediate or functional layer of the coating layer. In the current embodiment, the core material is a nickel alloy with a Curie temperature in the range of about 260°C to 450°C. This Curie temperature is advantageous in terms of temperature control and controlled heating of the aerosol-forming substrate. During heating, the coating layer reaches the Curie temperature of the nickel alloy, and the magnetic properties of the core material change from ferromagnetism to paramagnetism, accompanied by a sudden change in its resistance. Therefore, by monitoring the corresponding change in the current output by the induction power supply, it can be detected whether the coating layer induction heating material has reached its Curie temperature, and it is operated at the predefined heating temperature of the core material through feedback control.

[0044] about Figure 1 and Figure 2 In the embodiment shown, the composite induction heating wire is composed of 1J50 core material 1 and 430 cladding layer 2, with a wire length L of 11 mm and a composite structure of 20 um cladding layer A and 10 um core material B. The wire is drawn from 430 seamless tubes wrapped with 1J50 rods, with an outer diameter of 60 um.

[0045] Figure 3An exemplary embodiment of a composite induction heating material according to the present invention is schematically shown. The heating-not-burning moxibustion product includes three elements arranged in series: an aerosol generating matrix, an aerosol cooling element, and an aerosol gathering element. The aerosol generating matrix and the aerosol cooling element are roughly cylindrical, each having substantially the same diameter. The aerosol gathering element is an umbrella element. The three elements are arranged in sequence. The composite induction heating wire is located in the aerosol generating matrix, distributed in a bundle and in close contact with the aerosol generating matrix. The length of the composite induction heating wire is approximately the same as that of the aerosol generating matrix, and the axis of the composite induction heating wire is almost parallel to the axis of the aerosol generating matrix. The aerosol generating matrix includes an aggregated flocculent material of a homogenized moxa material surrounded by a packaging material.

[0046] Figure 3 The heat-not-burn moxibustion product shown is designed to be combined with an induction heating device. The induction heating device may include an induction source having an induction coil or an inductor for generating an alternating, especially high-frequency electromagnetic field. After the heat-not-burn moxibustion product is coupled to the induction heating device, the composite induction heating wire of the heat-not-burn moxibustion product is positioned in the electromagnetic field. The aerosol generated by heating flows into the aerosol gathering element after being cooled by the aerosol cooling element, thereby acting on human skin.

[0047] The specific applications of composite induction heating wires include but are not limited to heat-not-burn aromatherapy, heat-not-burn electric mosquito coils and other heat-not-burn products.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A composite wire material for forming a matrix for induction heating aerosol, characterized in that: The invention comprises a core material and a cladding layer arranged closely around the core material, wherein the cladding layer comprises an induction heating layer, the core material comprises a temperature feedback material having a Curie temperature lower than 550°C, and the composite wire material is an axisymmetric structure or a centrosymmetric structure; the axisymmetric structure or the centrosymmetric structure offsets the stress generated by the difference in thermal expansion of different materials in the composite wire material, so that the composite wire material only generates symmetrical internal stress changes within the working temperature range, and the overall thermal deformation is small; the working temperature range is at least 50K lower than the Curie temperature of the temperature feedback material and extends to the Curie temperature of the temperature feedback material.

2. A composite wire material for induction heating aerosol forming matrix according to claim 1, characterized in that: The coating layer is a multi-layer layer, one or more of which are anti-leakage layers, and the anti-leakage layers are made of metal materials or non-metal materials.

3. A composite wire material for induction heating aerosol forming matrix according to claim 1, characterized in that: The induction heating layer is used for induction heating of the aerosol-forming substrate, and the Curie temperature of the temperature feedback material of the core material corresponds to a predefined heating temperature of the composite filament.

4. A composite wire material for induction heating aerosol forming substrate according to claim 1, characterized in that: The cross-sections of the core material and the cladding layer are axially symmetrical or centrally symmetrical.

5. A composite wire material for induction heating aerosol forming substrate according to claim 4, characterized in that: The cross sections of the core material and the cladding layer are rectangular or concentric circles.

6. A composite wire material for induction heating aerosol forming substrate according to claim 1, characterized in that: The induction heating layer also has a Curie temperature. The Curie temperature of the core material is a first Curie temperature. The Curie temperature of the induction heating layer is a second Curie temperature. The second Curie temperature is higher than the first Curie temperature.

7. A composite wire material for induction heating aerosol forming substrate according to claim 2, characterized in that: When the coating layer is a multi-layer structure, each coating layer may have a Curie temperature different from that of the other.

8. A composite wire material for induction heating aerosol forming substrate according to claim 1, characterized in that: The induction heating layer includes one or more of ferromagnetic metal, paramagnetic metal and ferrimagnetic material.

9. A composite wire material for induction heating aerosol forming substrate according to claim 1, characterized in that: The core material has a Curie temperature between 150°C and 550°C.

10. The composite wire material for induction heating aerosol forming substrate according to claim 1, characterized in that: The induction heating layer is mainly used to heat the aerosol-forming substrate, and the induction heating layer has a Curie temperature exceeding 600°C.

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