Heating diaphragm and preparation method therefor, heating pipe and heating electric appliance

Abstract

Provided are a heating diaphragm and a preparation method therefor, a heating pipe and a heating electric appliance. The raw materials of the heating diaphragm comprise natural graphite and / or graphene, and the weight of the heating diaphragm having a length of 1 decimeter is 0.02-2 g.

Description

Heating diaphragm and preparation method thereof, heating tube and heating appliance

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the benefit of priority to Chinese patent application No. 2024101198333, filed on January 26, 2024, and incorporates the entirety of the patent application herein. Technical Field

[0003] The present disclosure relates to the field of electrical appliance technology, and more specifically, to a heating diaphragm and a preparation method thereof, a heating tube, and a heating appliance. Background Art

[0004] Traditional electric ovens primarily heat the air inside the oven cavity, thereby heating the food, and directly heat the food surface through heat radiation. Currently, the heating components used in electric ovens, microwave ovens, steam ovens, and other heating appliances on the market mainly include metal heating tubes (maximum heating temperature range between 550 and 750°C), quartz heating tubes (heating wire temperature range between 660 and 800°C), halogen heating tubes (maximum heating temperature less than 1000°C), and carbon fiber heating tubes (maximum heating temperature less than 1000°C). However, these heating tubes have disadvantages such as insufficient heating speed within the heating temperature range, insufficient temperature, and heavy weight. This increases cooking time and makes it difficult to achieve a crispy exterior and tender interior during the heating process, resulting in a poor user experience. Furthermore, current heating tubes are relatively heavy, which is not conducive to the design requirement of lightweight design.

[0005] Summary of the Invention

[0006] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one purpose of the present disclosure is to provide a heating diaphragm with a light weight, a high heating temperature or a fast heating rate.

[0007] In one aspect of the present disclosure, the present disclosure provides a heating film. According to an embodiment of the present disclosure, the raw materials of the heating film include natural graphite and / or graphene, and the weight of the heating film of 1 decimeter length is 0.02 to 2g. Thus, the heating film made of graphite material prepared by natural graphite or graphene makes the heating temperature of the heating film higher and the heating rate faster, which can help to achieve higher temperature heating and more efficient heating efficiency; moreover, the heating film of the present disclosure adopts natural graphite, and natural graphite ore has large reserves in the earth's minerals. At the same time, the carbon-based film material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously to reduce costs. In summary, the heating film of the present disclosure has the advantages of a wide source of raw materials, a simple preparation process, good product stability, and performance parameters that can be easily adjusted according to demand. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product types. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating film and reduce production efficiency. Using graphene as a raw material is not only conducive to obtaining a heating film with a higher carbon content, but also has a simple and mature processing technology and a low preparation cost. Moreover, the above-mentioned heating film disclosed in the present invention is relatively light in weight, much less than the weight of heating tubes such as metal heating tubes or quartz tubes, which contributes to the lightweight design of the heating film disclosed in the present invention and helps to obtain a lighter heating tube. If the weight of the heating film per unit length is less than 0.02g, the manufacturability of the heating film is relatively poor, which in turn affects the overall performance of the heating film. If the weight of the heating film per unit length is greater than 2g, the manufacturability of the heating film is relatively poor.

[0008] According to an embodiment of the present disclosure, the heating diaphragm has a sheet-like structure, the graphite and the graphene have a sheet-like structure, and the sheet-like extension plane of the heating diaphragm is substantially consistent with the sheet-like extension plane of the graphite and / or the graphene.

[0009] According to an embodiment of the present disclosure, the time for the heating film to reach the maximum heating temperature is 0.1s to 2s.

[0010] According to an embodiment of the present disclosure, the heat-resistant temperature of the heating film is greater than or equal to 2500°C.

[0011] According to an embodiment of the present disclosure, the maximum heating temperature of the heating film is 500°C to 1700°C.

[0012] According to an embodiment of the present disclosure, the heating film is made of graphite.

[0013] According to an embodiment of the present disclosure, the power of the heating film is 15W to 10000W.

[0014] According to an embodiment of the present disclosure, the heating film includes a plurality of heating units sequentially arranged along the length direction, and adjacent heating units are arranged at intervals and connected by connecting sections.

[0015] According to an embodiment of the present disclosure, each of the heating units is provided with a hollow hole.

[0016] In another aspect of the present disclosure, a method for preparing the aforementioned heating film is provided. According to an embodiment of the present disclosure, the method for preparing the heating film includes: providing natural graphite and performing an intercalation treatment on the natural graphite to obtain graphite oxide; performing an expansion treatment on the graphite oxide to obtain expanded graphite; performing calendaring and cutting on the expanded graphite to obtain the heating film, or includes: mixing and dispersing the graphene and additives uniformly to obtain a dispersion; applying the dispersion to obtain a dispersion film; performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; and calendaring and cutting the carbon-based primary film to obtain the heating film. Thus, the heating diaphragm made of graphite material obtained by using natural graphite or graphene makes the heating temperature of the heating diaphragm higher and the heating rate faster, which can help achieve higher temperature heating and more efficient heating efficiency; moreover, the heating diaphragm disclosed in the present invention uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously, reducing costs. In summary, the carbon-based diaphragm material has the advantages of a wide source of raw materials, simple preparation process, good product stability, and performance parameters that can be easily adjusted according to demand. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product varieties. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; using graphene as a raw material is not only conducive to obtaining a heating diaphragm with a higher carbon content, but also has a simple and mature processing technology and low preparation cost.

[0017] According to an embodiment of the present disclosure, the method for preparing the aforementioned heating film includes: mixing and dispersing the graphene microsheets and additives evenly to obtain a dispersion; coating the dispersion to obtain a dispersion film; performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; and calendering and cutting the carbon-based primary film to obtain the heating film.

[0018] In another aspect of the present disclosure, a heat pipe is provided. According to an embodiment of the present disclosure, the heat pipe includes the aforementioned heating film. As a result, the heat pipe is lightweight, generates heat at a higher temperature, and heats up at a faster rate. Those skilled in the art will appreciate that the heat pipe possesses all the features and advantages of the aforementioned heating film, and no further elaboration is required here.

[0019] In yet another aspect of the present disclosure, a heating appliance is provided. According to an embodiment of the present disclosure, the heating appliance includes the aforementioned heating tube. As a result, the heating appliance generates heat faster and at higher temperatures. Those skilled in the art will appreciate that the heating appliance possesses all the features and advantages of the aforementioned heating film, and further details will not be given here.

[0020] According to an embodiment of the present disclosure, the heating appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric fan heater, an electric heater, a bathroom heater, an electric ceramic stove or a disinfection cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] FIG1 is a schematic diagram of heat radiation of a heating film disclosed in the present invention;

[0023] FIG2 is a schematic diagram of heat radiation of a heating pipe in the prior art;

[0024] FIG3 is a schematic structural diagram of a heating membrane in an embodiment of the present disclosure;

[0025] FIG4 is a schematic structural diagram of a heating film in other embodiments of the present disclosure;

[0026] FIG5 is a schematic structural diagram of a heating film in other embodiments of the present disclosure;

[0027] FIG6 is a schematic structural diagram of a heating film in other embodiments of the present disclosure;

[0028] FIG7 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0029] FIG8 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0030] FIG9 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0031] FIG. 10 is a temperature-resistance curve diagram of a heating film in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will understand that the following examples are only used to illustrate the present disclosure and should not be regarded as limiting the scope of the present disclosure. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be obtained commercially.

[0033] The present disclosure is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present disclosure in any way.

[0034] In one aspect of the present disclosure, the present disclosure provides a heating film. According to some embodiments of the present disclosure, the raw materials of the heating film include natural graphite and / or graphene, and the weight of the heating film of 1 decimeter length is 0.02 to 2g, such as 0.02g, 0.04g, 0.05g, 0.1g, 0.2g, 0.5g, 1g, 1.5g, 2g, etc. Thus, the heating film made of graphite material prepared by natural graphite or graphene makes the heating film have a higher heating temperature and a faster heating rate, which can help to achieve higher temperature heating and more efficient heating efficiency; moreover, the heating film of the present disclosure uses natural graphite, and natural graphite ore has large reserves in the earth's minerals. At the same time, the carbon-based film material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously to reduce costs. In summary, the heating film disclosed in the present invention has the advantages of a wide range of raw material sources, a simple preparation process, good product stability, and performance parameters that can be easily adjusted according to demand. It has great advantages in reducing product costs, enhancing product reliability, and enriching product varieties. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating film and reduce production efficiency. Using graphene as a raw material is not only conducive to obtaining a heating film with a high carbon content, but also has a simple and mature processing technology and low preparation cost. Moreover, the above-mentioned heating film disclosed in the present invention is light in weight, far less than the weight of heating tubes such as metal heating tubes or quartz tubes, which contributes to the lightweight design of the heating film disclosed in the present invention and helps to obtain a lighter heating tube. If the weight of the heating film per unit length is less than 0.02g, the manufacturability of the heating film is relatively poor, which in turn affects the overall performance of the heating film. If the weight of the heating film per unit length is greater than 2g, the manufacturability of the heating film is relatively poor. Furthermore, as the weight of the heating diaphragm per unit length increases, the heating power of the heating diaphragm gradually increases, that is, the weight of the heating diaphragm per unit length is positively correlated with the heating power of the heating diaphragm. Therefore, the required power of the heating diaphragm can be adjusted by adjusting the weight of the heating diaphragm per unit length.

[0035] According to the heat calculation formula Q=m*Cp*ΔT, in which Q-heat; m-mass; Cp-specific heat; ΔT-temperature rise. According to this formula, under the same heat, the smaller the mass*specific heat, the greater the temperature rise. Since the heating film of the present invention is light in mass and its specific heat capacity is not large, the product of its mass and specific heat is small. Therefore, under the same heat conditions, the temperature rise rate of the carbon-based film is faster and the heating temperature is higher. In a specific embodiment of the present invention, the specific heat capacity of the carbon-based heating film is 0.71kJ / (kg*K) and the mass is 0.216g. The specific heat capacity of the metal heating wire of the heating tube such as the metal tube or quartz tube is 0.49kJ / (kg*K) and the mass is 5g. It can be seen that compared with the metal heating wire, the temperature rise rate of the carbon-based film of the present invention is faster and the heating temperature can also reach a higher level.

[0036] Furthermore, according to the radiation heat transfer formula: Q=ε*σ*A*(T1 4 -T2 4 ), where Q is the heat quantity; ε is the emissivity; σ is the Boltzmann constant; and T is the surface temperature. This shows that radiative heat transfer is proportional to the fourth power difference between the two surface temperatures. Since the carbon-based diaphragm surface temperature is higher, the radiative heat transfer Q is higher, which in turn makes the carbon-based diaphragm heating tube heat faster than metal tubes and quartz tubes.

[0037] In some embodiments of the present disclosure, the raw graphene material may be graphene nanoplatelets, which are ultrathin graphene layered stacks with more than 10 carbon layers and a thickness in the range of 5-100 nanometers. Graphene nanoplatelets have excellent thermal conductivity and tensile strength, thereby helping to improve the heating temperature and mechanical strength of the prepared heating film.

[0038] According to some embodiments of the present disclosure, the heating film has a sheet-like structure, and the raw material graphite and / or graphene used to prepare the heating film has a sheet-like structure, and the sheet-like extension plane of the heating film is substantially consistent with the sheet-like extension plane of natural graphite and / or graphene. Therefore, as shown in Figure 1, when the sheet-like heating film generates heat, the heat is mainly radiated in the vertical direction of the heating surface (i.e., the plane of the film), with strong directivity and more concentrated radiated heat, which can better improve the heating efficiency and reduce heat loss. In the current prior art, referring to Figure 2, the heat radiation of the heating tube core 1 (such as a metal heating tube core or a quartz tube core) is evenly emitted in all directions, and the heat cannot be concentrated. This usually causes heat waste and reduces heating efficiency. Therefore, by comparison, it can be seen that the heat radiation direction of the heating film of the present disclosure is more concentrated, which can better direct the heating of the object to be heated and improve heating efficiency. It should be noted that the above-mentioned "substantially consistent" means that the sheet-like extension plane of the heating film is roughly consistent with the sheet-like extension plane of natural graphite and / or graphene, and does not require that the two are completely consistent or completely parallel.

[0039] According to some embodiments of the present disclosure, as described above, the heating film prepared from the raw material natural graphite or graphene is made of graphite, which enables the heating film of the present disclosure to have a higher heating temperature and a faster heating rate. The prepared graphite still has a flaky structure, and the plane extension direction of the flaky structure is substantially consistent with the plane extension direction of the raw material natural graphite or graphene. Therefore, it can be said that the flaky extension plane of the heating film is substantially consistent with the flaky extension plane of the graphite material it is made of.

[0040] According to some embodiments of the present disclosure, the time for the heating film to reach the maximum heating temperature is 0.1s to 2s, such as 0.1s, 0.2s, 0.4s, 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s, 2.0s, etc. It can be seen that the heating film of the present disclosure has a fast heating speed and can reach the maximum heating temperature in a shorter time, thereby greatly improving the heating efficiency of the heating film.

[0041] According to some embodiments of the present disclosure, the heat-resistant temperature of the heating film is greater than or equal to 2500°C, such as 2500°C, 2550°C, 2600°C, 2650°C, 2700°C, 2750°C, 2800°C, 2850°C, 2900°C, 2950°C, 3000°C, etc. It can be seen that the heat-resistant temperature of the heating film of the present disclosure is relatively high, and thus it can reach a relatively high heating temperature without causing any qualitative changes.

[0042] According to some embodiments of the present disclosure, the maximum heating temperature of the heating film is 500°C to 1700°C. For example, the maximum heating temperature of the heating film can be 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C, etc. It can be seen that the heating film of the present disclosure has a relatively high maximum heating temperature, even up to 1700°C, thereby meeting more application heating requirements of the heating film and obtaining heating films of various powers, such as ultra-low power heating films or ultra-high power heating films.

[0043] According to some embodiments of the present disclosure, the thickness of the heating film is 0.04mm to 2mm, for example, the thickness of the heating film is 0.04mm, 0.06mm, 0.08mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, etc. The heating film of the above thickness can meet the requirements of different power sizes of the heating film; moreover, the carbon-based heating film of the present disclosure has high manufacturability, that is, high production yield and long service life; in addition, the thick base of the heating film is thin, which facilitates the design of the heating film to meet the requirements of lightness.

[0044] According to some embodiments of the present disclosure, the density of the heating film is 0.6 g / cm 3 ~1.8g / cm 3 For example, the density of the heating film is 0.6g / cm 3 , 0.8g / cm 3 , 1.0g / cm 3 , 1.2g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.8g / cm 3 The heating film of the above density can meet the requirements of different power sizes for the heating film; moreover, the carbon-based heating film disclosed in the present invention has high manufacturability, that is, high production yield and long service life; and the combination of the above density and the above thickness can flexibly adjust the power of the heating film to meet various power requirements.

[0045] According to some embodiments of the present disclosure, the power of the heating diaphragm is 15W to 10000W, such as 15W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 4500W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc. Therefore, the heating diaphragm of the present disclosure can effectively realize a heating diaphragm with different powers over a large span, that is, it can realize an ultra-low power heating diaphragm, and it can also realize an ultra-high power heating diaphragm, meeting the power usage requirements of the heating diaphragm under various application conditions.

[0046] According to some embodiments of the present disclosure, the carbon content of the heating film is greater than or equal to 99%. Therefore, the carbon content of the heating film is higher, that is, the purity is higher, which is conducive to obtaining a heating film with better performance.

[0047] According to some embodiments of the present disclosure, the thermal diffusion coefficient of the heating film is 50m 2 / s~450m 2 / s, for example, 50m 2 / s、80m 2 / s、100m 2 / s、130m 2 / s、150m 2 / s、280m 2 / s、300m 2 / s、320m 2 / s、350m 2 / s、370m 2 / s、400m 2 / s, etc. The above thermal diffusion coefficient can make the heat emitted by the heating diaphragm less transferred out of the heating cavity in the form of heat conduction, so that more heat is concentrated on the heating diaphragm, and the heating diaphragm has a higher temperature. According to Boltzmann's law, the greater the temperature difference, the greater the radiation energy, and more heat is transferred to the heating cavity in the form of radiation, so that the heat generated by the heating diaphragm is mainly concentrated on the object to be heated. In this way, a better heating rate can be guaranteed without transferring heat too quickly, resulting in a large heat loss, thereby improving the heating efficiency. Moreover, the above thermal diffusion coefficient also helps to extend the service life of the heating diaphragm. The thermal diffusion coefficient is less than 50m 2 / s, the heat transferred by the heating diaphragm in the form of heat conduction is too little, making the temperature of the heating diaphragm too high and the service life cannot meet the requirements; the thermal diffusion coefficient is greater than 450m 2 / s, the heat conducted out is more, the radiation energy is less, the heating efficiency of the heating film is low, and the higher the thermal diffusion coefficient, the higher the density of the heating film required to be made. The thermal diffusion coefficient is greater than 450m 2 / s corresponds to a higher density, making it more difficult to manufacture. At the same time, the carbon-based heating film disclosed herein has readily available raw materials at a low cost, and does not require high-temperature graphitization, making the process simpler and safer. Furthermore, the aforementioned thermal diffusivity helps extend the life of the heating film and improve its manufacturability.

[0048] According to some embodiments of the present disclosure, the heating film prepared by natural graphite and / or graphene microsheets also has the characteristic of self-limiting temperature. Referring to Figure 10, the heating film has a critical temperature. When the temperature of the heating film is less than the critical temperature, the resistance of the heating film decreases as the temperature increases; when the temperature of the heating film is greater than the critical temperature, the resistance of the heating film increases as the temperature increases. It can be seen that the heating film of the present disclosure has the characteristic of self-limiting temperature. Specifically: in the initial stage of heating (that is, when the temperature of the heating film is less than the critical temperature), the resistance of the heating film decreases as the temperature increases, and the current increases, so that the power of the heating film increases with the temperature increase, so in this stage, the heating film can heat up rapidly; when the heating temperature of the heating film reaches the critical temperature, the resistance of the heating film increases as the temperature increases, and the current decreases, so that the power of the heating film decreases as the temperature increases, so in this stage, the heating rate of the heating film begins to slow down, and slowly gradually reaches the maximum heating temperature of the heating film. The self-limiting temperature characteristic of the heating film can, on the one hand, accelerate the heating rate of the heating film in the temperature zone below the critical temperature, allowing the heating film to reach the target temperature as quickly as possible. On the other hand, when the temperature is above the critical temperature, it can reduce the problem of melting caused by the continuous increase in the heating temperature, for example, it can improve the reliability and stability of the heating film. It should be noted that Figure 10 is only a temperature-resistance curve diagram of the heating film in one embodiment, but the trend of this curve represents the temperature-resistance curve schematic diagram of the heating film disclosed in the present invention.

[0049] Furthermore, when the temperature of the heating diaphragm is lower than the critical temperature, the heating diaphragm has a first heating rate, and when the temperature of the heating diaphragm is higher than the critical temperature, the heating diaphragm has a second heating rate, wherein the first heating rate is higher than the second heating rate. Thus, the heating diaphragm of the present disclosure has a first heating rate that is faster, which can accelerate the heating speed of the heating diaphragm, allowing it to reach the critical temperature in a shorter period of time, and then continue to heat up at a relatively smaller second heating rate, thereby avoiding the problem of melting caused by the continuous increase in heating temperature, such as improving the reliability and stability of the heating diaphragm.

[0050] According to some embodiments of the present disclosure, the critical temperature value of the heating diaphragm is 50°C-500°C. For example, the critical temperature of the heating diaphragm can be 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 230°C, 250°C, 280°C, 300°C, 330°C, 350°C, 370°C, 400°C, 420°C, 450°C, 480°C, 500°C, etc. It can be seen that the heating diaphragm of the present disclosure can adjust the specific critical temperature value of the heating diaphragm within a wider range. If the heating temperature of the heating diaphragm is higher, a higher critical temperature value can be selected. If the heating temperature of the heating diaphragm is lower, a lower critical temperature value can be selected. In this way, the faster heating speed of the heating diaphragm and the problem of preventing melting can be better guaranteed at the same time.

[0051] In the embodiments of the present disclosure, the specific cutting shape of the heating film can be diversified. Those skilled in the art can flexibly design the cutting shape of the heating film according to the actual requirements of the resistance, power, etc. of the heating film. The following introduces some cutting shapes of the heating film based on some specific embodiments of the present disclosure:

[0052] In some embodiments of the present disclosure, referring to FIG3 , the heating film includes a plurality of heating units 01 arranged sequentially along the length direction, with adjacent heating units 01 spaced apart and connected by connecting sections 02 . Thus, the heating film of the present disclosure can be cut into a variety of different cut-out structures to meet different usage requirements. Specifically, in some embodiments of the present disclosure, referring to FIG3 , the outer peripheral wall of the heating unit is formed into an oblong or polygonal shape.

[0053] In some embodiments of the present disclosure, referring to (b), (c), and (i) in FIG3 , each heating unit 01 is provided with a hollow hole 03. Thus, the provision of the hollow hole can accelerate the heat dissipation rate of the heating membrane and accelerate the heating rate of the object to be heated.

[0054] In some embodiments of the present disclosure, referring to FIG4 , the heating diaphragm includes a first heating segment S1 and a second heating segment S2 adjacent to each other in the length direction, the first heating segment S1 includes a plurality of connected heating units 01, the second heating segment S2 includes a plurality of adjacent heating units 01, the size of the heating unit 01 corresponding to the first heating segment S1 is smaller than the size of the heating unit 01 corresponding to the second heating segment S2, such as in FIG4 (a), the length of the heating unit 01 corresponding to the first heating segment S1 is the same as the length of the heating unit 01 corresponding to the second heating segment S2, but the widths d1 and d2 of the two are different, such as in FIG4 (b) and (c), the width of the heating unit 01 corresponding to the first heating segment S1 is the same as the width of the heating unit 01 corresponding to the second heating segment S2, but the lengths d1 and d2 of the two are different. This can achieve diversification of the heating diaphragm structure.

[0055] In some embodiments of the present disclosure, referring to FIG5 , the first heating segment S1 and the second heating segment S2 are staggered in the width direction of the heating diaphragm, thereby achieving a diversified structure of the heating diaphragm.

[0056] In some embodiments of the present disclosure, referring to (d), (e), (f), (h), (i), and (j) in FIG3 , the heating diaphragm includes a plurality of notches spaced apart along its length. This allows for a variety of heating diaphragm structures. Furthermore, in some embodiments of the present disclosure, referring to (i) in FIG3 , each notch is defined by separating a portion of the heating diaphragm from the rest and then bending it.

[0057] In some embodiments, as shown in FIG6 , the same heating film may include a plurality of different cut types, or include the same cut type with uneven density distribution.

[0058] In another aspect of the present disclosure, a method for preparing the aforementioned heating film is provided. According to an embodiment of the present disclosure, the method for preparing the heating film can be prepared by using natural graphite and graphene respectively, and the specific preparation steps are as follows:

[0059] In some embodiments, a method for preparing a heating film using natural graphite includes:

[0060] S100: providing natural graphite and subjecting it to intercalation treatment to obtain graphite oxide (expandable graphite).

[0061] In the present disclosure, natural graphite is used, which does not need to be prepared through other processes, and can further reduce the process flow of preparing the heating diaphragm and reduce costs. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; moreover, the use of natural flake graphite, the graphite single-layer structure is a layered structure, which can make the graphite in the prepared heating diaphragm also have a layered structure, thereby improving the centralized heating effect of the heating diaphragm. In addition, natural flake graphite has large reserves in the earth's minerals. At the same time, the carbon-based heating diaphragm material does not require high-temperature graphitization during the preparation process, and can be produced continuously, which can further improve production efficiency and reduce production costs; the lack of high-temperature graphitization also improves production safety.

[0062] In addition, natural flake graphite has large reserves in the earth's mineral resources. At the same time, the heating membrane material disclosed in the present invention does not require high-temperature graphitization during the preparation process and can be produced continuously, which can further improve production efficiency and reduce production costs; the absence of high-temperature graphitization also improves production safety.

[0063] In some embodiments, the specific method of intercalation treatment can be to intercalate natural flake graphite with oxides such as concentrated sulfuric acid and / or hydrogen peroxide to obtain expandable graphite.

[0064] S200: performing expansion treatment on graphite oxide to obtain expanded graphite.

[0065] In some embodiments, upon entering the expansion furnace, expandable graphite experiences a transient high temperature, rapidly expanding to form graphite worms, also known as expanded graphite. This expansion process can achieve expansion multiples of 30 to 400 times. The expansion process occurs at a temperature of 850-1200°C and for a time of 0.7 to 1.3 seconds.

[0066] S300: Rolling, first heat treatment, and cutting the expanded graphite to obtain a heating film. The heating films obtained after cutting can be seen in Figures 3 to 6. The specific cutting characteristics are consistent with the requirements described above and will not be described in detail here.

[0067] There are no special requirements for the specific method of the first heat treatment, and those skilled in the art can adopt the specific heat treatment method for deoxidizing graphite oxide to obtain graphite in the prior art.

[0068] In this way, by rolling the expanded graphite, the thickness, density, thermal diffusion coefficient and other parameter characteristics of the heating film can be controlled. The thickness, density and thermal diffusion coefficient of the heating film are as described above and will not be described in detail here.

[0069] In some embodiments, the critical temperature of the heating film prepared by using natural graphite is 50-200° C. Therefore, a heating film with a lower critical temperature can be prepared by the above method.

[0070] According to the embodiments of the present disclosure, the heating diaphragm made of graphite material obtained by using natural graphite as mentioned above makes the heating temperature of the heating diaphragm higher and the heating rate faster, which can help to achieve higher temperature heating and more efficient heating efficiency; moreover, the heating diaphragm disclosed in the present disclosure uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously to reduce costs. In general, the carbon-based diaphragm material has the advantages of a wide source of raw materials, a simple preparation process, good product stability, and performance parameters that can be easily adjusted according to demand. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product types. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency.

[0071] In some embodiments, a method for preparing a heating film using graphene includes:

[0072] S400: The graphene and the additive are mixed and dispersed uniformly to obtain a dispersion.

[0073] In some embodiments, the graphene used is a graphene microplatelet, the plane size of the graphene microplatelet is 1-100 μm, and the specific surface area is 30-800 m 2 / g, the graphene microsheets required above are easy to disperse evenly.

[0074] In some embodiments, the additive includes at least one of carboxymethyl cellulose, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, and water-based polyurethane. The addition of the above additives can effectively increase the film-forming property of the graphene microsheets.

[0075] Furthermore, based on the total mass of the dispersion, the mass fraction of the additive is less than or equal to 5%, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. The amount of the additive is low and will not affect the good performance of the prepared heating film.

[0076] S500: The dispersion liquid is applied to obtain a dispersion liquid film.

[0077] In some embodiments, there are no special requirements for the specific coating method. Those skilled in the art can flexibly select an appropriate coating method according to actual needs, such as spin coating, spray coating, etc.

[0078] S600: performing a second heat treatment on the dispersion film to obtain a carbon-based primary film.

[0079] In this step, the graphene is deoxidized through a second heat treatment to produce a graphite material. The heat treatment can be performed under vacuum or an inert atmosphere at a temperature of 1500-3000°C. This method can produce graphite with a high carbon content, for example, a carbon content exceeding 99%.

[0080] S700: The carbon-based primary film is rolled and cut to obtain a heating film. The heating film of different cuts obtained after cutting can be referred to Figures 3 to 6. The specific cutting characteristics are consistent with the requirements described above and will not be described in detail here.

[0081] In some embodiments, the critical temperature of the heating film prepared from the graphene microsheet is 150-500° C. Therefore, a heating film with a higher critical temperature can be prepared by the above method.

[0082] According to the embodiments of the present disclosure, the use of graphene as a raw material not only facilitates the production of a heating film with a high carbon content, but also allows for a simple and mature processing technique and low production costs. Furthermore, the graphene microsheets used have excellent thermal conductivity and tensile strength, thereby helping to improve the heating temperature and mechanical strength of the prepared heating film.

[0083] In another aspect of the present disclosure, a heat pipe is provided. According to an embodiment of the present disclosure, the heat pipe includes the aforementioned heating film. As a result, the heat pipe is lightweight, generates heat at a higher temperature, and heats up at a faster rate. Those skilled in the art will appreciate that the heat pipe possesses all the features and advantages of the aforementioned heating film, and no further details will be given here.

[0084] In some embodiments, referring to Figure 7 (the S area in the figure refers to a partial cross-sectional view of the sleeve), Figure 8 and Figure 9, the heating tube also includes a sleeve 10, and the heating membrane 20 is placed in the sleeve 10. Terminals 21 are provided at both ends of the heating membrane 20, wherein the sleeve can be a quartz glass tube or the like.

[0085] In another aspect of the present disclosure, a heating appliance is provided. According to an embodiment of the present disclosure, the heating appliance includes the aforementioned heating tube. As a result, the heating appliance generates heat faster and at higher temperatures. Those skilled in the art will appreciate that the heating appliance possesses all the features and advantages of the aforementioned heating film, and further details will not be given here.

[0086] According to an embodiment of the present disclosure, the heating appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric fan heater, an electric heater, a bathroom heater, an electric ceramic stove or a disinfection cabinet.

[0087] Those skilled in the art will understand that, in addition to the above-mentioned heating tubes, the heating appliance also includes the necessary structures or components of the heating appliance. Taking the electric oven as an example, in addition to the above-mentioned heating tubes, it also includes the necessary structures or components such as the shell, heating space, base, and plug.

[0088] Example

[0089] Example 1

[0090] The heating film is made of natural flake graphite. The structural diagram of the heating film can be referred to (a) in Figure 3. The thickness of the heating film is 0.04mm, the length is 3dm, the width is 8mm, and the density is 1g / cm 3 .

[0091] Example 2

[0092] The difference from Example 1 is that the thickness of the heating film is 0.1 mm.

[0093] Example 3

[0094] The difference from Example 1 is that the thickness of the heating film is 0.5 mm.

[0095] Example 4

[0096] The difference from Example 1 is that the thickness of the heating film is 1 mm.

[0097] Example 5

[0098] The difference from Example 1 is that the thickness of the heating film is 1.5 mm.

[0099] Example 6

[0100] The difference from Example 1 is that the thickness of the heating film is 2 mm.

[0101] Example 7

[0102] The difference from Example 1 is that the length of the heating film is 2 dm.

[0103] Example 8

[0104] The difference from Example 1 is that the length of the heating film is 6 dm.

[0105] Comparative Example 1

[0106] The difference from Example 1 is that the thickness of the heating film is 0.03 mm.

[0107] Comparative Example 2

[0108] The difference from Example 1 is that the thickness of the heating film is 2.2 mm.

[0109] Comparative Example 3

[0110] It uses a metal heating core with a length of 3dm.

[0111] Comparative Example 4

[0112] It uses a quartz tube core with a length of 3dm.

[0113] Example 9

[0114] The heating film is made of graphene microsheets. The structural diagram of the heating film can be seen in Figure 3 (a). The thickness of the heating film is 0.04mm, the length is 3dm, the width is 8mm, and the density is 1g / cm 3 .

[0115] Example 10

[0116] The difference from Example 9 is that the thickness of the heating film is 0.1 mm.

[0117] Example 11

[0118] The difference from Example 9 is that the thickness of the heating film is 0.5 mm.

[0119] Example 12

[0120] The difference from Example 9 is that the thickness of the heating film is 1 mm.

[0121] Example 13

[0122] The difference from Example 9 is that the thickness of the heating film is 1.5 mm.

[0123] Example 14

[0124] The difference from Example 9 is that the thickness of the heating film is 2 mm.

[0125] Comparative Example 5

[0126] The difference from Example 9 is that the thickness of the heating film is 0.03 mm.

[0127] Comparative Example 6

[0128] The difference from Example 9 is that the thickness of the heating film is 2.2 mm.

[0129] The mass, maximum heating temperature, heating response time and power of the heating diaphragms in the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 2, as well as the mass, maximum heating temperature, heating response time and power of the heating tube cores in the above-mentioned Comparative Examples 3 and 4 were tested. The mass, maximum heating temperature, heating response time and power of the heating diaphragms in the above-mentioned Examples 9 to 14 and Comparative Examples 5 to 6 were tested. The test results are shown in Table 1.

[0130] The thickness of the heating diaphragm in Comparative Example 1 and Comparative Example 5 is too small, resulting in uneven overall thickness, insufficient manufacturability, and inability to conduct experimental tests; the thickness of the heating diaphragm in Comparative Example 2 and Comparative Example 6 is too large, resulting in easy breakage, insufficient manufacturability, and the production qualification rate does not meet the manufacturing requirements.

[0131] Table 1

[0132] The above data shows that the response time of the heating film is related to the length of the heating film. The longer the heating film is, the longer its heating response time is. Furthermore, as the weight of the heating film per unit length increases, the heating power of the heating film gradually increases. Compared with Comparative Examples 3 and 4, it can be seen that the heating film of the present disclosure has an extremely short heating response time, is light in weight, can achieve rapid heating, and has a high heating temperature, and has a lightweight design of the heating tube.

[0133] Example 15

[0134] The heating tubes in Example 4, as well as the halogen tube, quartz tube, and metal tube were respectively used in the same oven. The power of all the heating tubes was tested to be 600W. The time required for each heating tube to reach 200°C at the center of the oven was tested. The test results can be seen in Table 2.

[0135] Table 2

[0136] It can be seen from the above embodiments and comparative examples that the heating film of the present disclosure has a lighter weight, a higher heating temperature, and a faster heating rate and temperature rising rate.

[0137] 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 the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0138] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 disclosure. 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 different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0139] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A heating film, wherein, The raw materials of the heating film include natural graphite and / or graphene, and the weight of the heating film with a length of 1 decimeter is 0.02 - 2 g.

2. The heating film according to claim 1, wherein, The heating film has a sheet structure, the graphite and the graphene have sheet structures, and the sheet extension plane of the heating film is basically the same as the sheet extension plane of the graphite and / or the graphene.

3. The heating film according to claim 1 or 2, wherein The time for the heating film to reach the maximum heating temperature is 0.1 s - 2 s.

4. The heating film according to any one of claims 1 to 3, wherein, The heat-resistant temperature of the heating film is greater than or equal to 2500 °C.

5. The heating diaphragm according to any one of claims 1 to 4, wherein, The maximum heating temperature of the heating film is 500 °C - 1700 °C.

6. The heating film according to any one of claims 1 to 5, wherein The material of the heating film is graphite.

7. The heating film according to any one of claims 1 to 6, wherein, The power of the heating film is 15 W - 10000 W.

8. The heating film according to any one of claims 1 to 7, wherein, The heating film includes a plurality of heating units arranged in sequence along the length direction, and adjacent heating units are spaced apart and connected by a connecting section.

9. The heating film according to claim 8, wherein, Each heating unit is provided with a hollow hole.

10. A method for preparing the heating diaphragm according to any one of claims 1 to 9, wherein, Comprising: Providing the natural graphite and subjecting it to intercalation treatment to obtain expandable graphite; Performing an expansion treatment on the expandable graphite to obtain expanded graphite; Performing calendering, first heat treatment, and cutting on the expanded graphite to obtain the heating film, Or, comprising: Mixing and uniformly dispersing the graphene and an additive to obtain a dispersion; Coating the dispersion to obtain a dispersion film; Performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; Performing calendering and cutting on the carbon-based primary film to obtain the heating film.

11. A heating tube, wherein, Comprising the heating film according to any one of claims 1 - 9.

12. A heating appliance, wherein, Comprising the heating tube according to claim 11.

13. The heating appliance according to claim 12, wherein, The heating appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric heater, an electric radiator, a bathroom heater, an electric ceramic stove, or a disinfection cabinet.

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