Heater cores, heater tubes, and home appliances

Abstract

This application discloses a heater core, a heater tube, and a home appliance, wherein the heater core includes a graphite film, the graphite film includes a heater region, the heater region includes a plurality of series-connected heater units, the heater units include sequentially connected first, second, third, and fourth parts, two adjacent heater units are connected via the first and fourth parts, the first and third parts extend along a first direction, the second and fourth parts extend along a second direction, the second direction is the direction of extension of the graphite film and intersects the first direction, the width of the graphite film is d0, and the widths of the first, second, third, and fourth parts are d1, d2, d3, and d4, respectively, and 2% ≤ d i / d0 ≤ 20% is satisfied, where i is 1, 2, 3, 4. i / d0≧2% improves the structural strength of the heater core and ensures the fall resistance of the heater core, d i By ensuring that / d0 ≥ 2%, excessive power density in the heater region of the graphite film due to low resistance can be avoided, thereby improving the service life of the heater core.

Description

[Technical Field]

[0001] This application claims priority to the Chinese patent application filed with the China National Intellectual Property Administration on April 26, 2023, with application number 202310470633.8, titled "Heater Cores, Heater Tubes and Home Appliances," and all contents of that application are incorporated into this application by reference.

[0002] This application relates to the technical field of home appliances, and more particularly to heater cores, heater tubes, and home appliances. [Background technology]

[0003] Conventional electric ovens heat food by heating the air inside the cavity with heating elements, and also by directly heating the surface of the food through heat radiation. The heating elements in commercially available electric ovens, microwave ovens, and steam ovens mainly use metal or quartz heating tubes. However, conventional heating tubes have low heating efficiency, failing to effectively concentrate energy, resulting in a slow temperature rise, longer cooking times, and difficulty in achieving a crispy exterior and soft interior texture during baking, thus degrading the user experience. In related technologies, graphite heating cores have been proposed to address these issues, but current graphite heating cores still have room for improvement. [Overview of the project]

[0004] This application aims to solve technical problems in related technologies to at least a certain extent. Therefore, this application submits a heater core.

[0005] To achieve the above objective, the present application discloses a heater core comprising a graphite film, the graphite film comprising a heater region, the heater region comprising a plurality of series-connected heater units, the heater units comprising sequentially connected first, second, third and fourth portions, two adjacent heater units being connected via the first and fourth portions, the first and third portions extending along a first direction, the second and fourth portions extending along a second direction, the second direction being the direction of extension of the graphite film and intersecting the first direction. The width of the graphite film is d0, and the widths of the first, second, third, and fourth parts are d1, d2, d3, and d4, respectively, and 2% ≤ d i The condition / d0 ≤ 20% is satisfied, where i is 1, 2, 3, or 4.

[0006] In some embodiments of this application, d0 is between 5 mm and 20 mm.

[0007] In some embodiments of this application, d i The size ranges from 0.1 mm to 4 mm.

[0008] In some embodiments of the present application, the area of ​​the heater unit is S, the power of the heater unit is P, and the power density is P d =P / S, and P d ≤70W / cm 2 It satisfies the condition.

[0009] In some embodiments of the present application, the first part and the second part are connected in an arc shape, the second part and the third part are connected in an arc shape, the third part and the fourth part are connected in an arc shape, and the fourth part and the first part are connected in an arc shape.

[0010] In some embodiments of the present application, the second direction is orthogonal to the first direction.

[0011] In some embodiments of the present application, the graphite film includes an intermediate region, there are two heater regions, the intermediate region is connected to the heater regions and is located between the two intermediate regions.

[0012] In some embodiments of the present application, the graphite film further includes connection regions located at both ends, the connection regions are connected to the heater regions, and the connection regions are suitable for being connected to lead wires.

[0013] The present application further discloses a heater tube, and the heater tube includes the above heater core.

[0014] In some embodiments of the present application, the heater tube further includes an outer tube, the heater core is provided inside the outer tube, and an inert gas is filled inside the outer tube.

[0015] The present application further discloses a household electrical appliance, and the household electrical appliance includes the above heater tube.

[0016] In the technical solution of the present application, d i / d0≥2% can reduce the difficulty of the manufacturing process of the heater core, improve the structural strength of the heater core, ensure the drop resistance of the heater core, so that the heater core is less likely to break or deform. Furthermore, d i / d0≤20% can avoid excessive total power due to a small resistance value, and thus avoid excessive power density in the heater region of the graphite film, and can improve the service life of the heater core.

[0017] Other advantages of the present application are partially shown in the following description, partially become apparent from the following description, or are understood by implementing the present application.

[0018] To more clearly explain the technical solutions in the embodiments of this application or the prior art, the drawings necessary for the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application, and those skilled in the art can obtain other designs based on the structures shown in these drawings without creative efforts.

Brief Description of Drawings

[0019] [Figure 1] It is a schematic diagram of a heater tube in some embodiments of the present disclosure. [Figure 2] It is a schematic diagram of a heater core in some embodiments of the present disclosure. [Figure 3] It is a schematic diagram of a heater core in some embodiments of the present disclosure.

Modes for Carrying Out the Invention

[0020] Description of Reference Signs Heater core 1000, graphite film 1100, heater region 1110, heater unit A, first part 1111, second part 1112, third part 1113, fourth part 1114, intermediate region 1120, connection region 1130, heater tube 2000, connection terminal 2100, lead wire 2200, outer tube 2300.

[0021] The realization of the object, functional features and advantages of this application will be further described while referring to the embodiments and the drawings.

[0022] Hereinafter, referring to the drawings in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative efforts are included in the protection scope of this application.

[0023] Furthermore, all direction indicators in the embodiments of this application (e.g., up, down, left, right, front, back, etc.) are solely for the purpose of describing the relative positional relationships and operating conditions between each component in a specific orientation (as shown in the drawings), and if that specific orientation is changed, the direction indicators will also be changed accordingly.

[0024] In this application, unless otherwise explicitly provided or limited, terms such as “connection” and “fixed” shall be interpreted broadly. For example, unless otherwise explicitly provided, “fixed” may be a fixed connection, a detachable connection, a single unit, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or an internal communication or interaction between two elements. A person skilled in the art will understand the specific meaning of these terms in this application depending on the specific circumstances.

[0025] Furthermore, in this application, expressions such as "first," "second," etc., are used merely for explanatory purposes and should not be understood as indicating or suggesting their relative importance or implying the number of technical features being referred to. For this reason, features designated as "first" or "second" may be explicitly or implicitly included in at least one of those features. While the technical solutions between each embodiment can be combined, this is contingent on them being feasible for a person skilled in the art. If a combination of technical solutions results in a contradiction or is impossible to implement, such a combination of technical solutions shall be deemed nonexistent and shall not be included in the scope of protection claimed by this application.

[0026] This application provides a heater core 1000, with reference to Figures 1 and 2, and in some embodiments of this application, the heater core 1000 includes a graphite film 1100, the graphite film 1100 is d iIt is necessary to satisfy the condition of / d0≥2%. This can reduce the difficulty of the manufacturing process of the heater core 1000, improve the structural strength of the heater core 1000, and ensure the drop resistance of the heater core 1000, making the heater core 1000 less likely to break or deform. Furthermore, d i It is also necessary to further satisfy / d0≤20%, avoid excessive total power due to a small resistance value, and thus avoid excessive power density in the heater region 1110 of the graphite film 1100, which can improve the service life of the heater core 1000.

[0027] Specifically, the main component of the graphite film 1100 is made of graphite and forms a flat structure, thereby forming a planar heater. Therefore, it can have higher heating efficiency, higher response speed, and faster temperature rise speed compared with conventional heater wires. This makes it possible to concentrate energy more, achieving a crispy exterior and tender interior texture when cooking food.

[0028] Generally, the heater core 1000 needs to extend along a certain direction for a certain length, while the graphite film 1100 constitutes a planar heater. Therefore, in order to form a larger heater area within a limited length, the graphite film 1100 includes a heater region 1110, and the graphite film 1100 mainly radiates heat through the heater region 1110. The heater region 1110 includes multiple heater units A, where multiple means two or more, and the multiple heater units A are connected in series, meaning the current flowing through each heater unit A is the same. The heater unit A has four The heater region 1110 includes four parts, which are the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111. Here, the third part 1113 and the first part 1111 extend along the first direction for a fixed length, and the fourth part 1114 and the second part 1112 extend along the second direction for a fixed length. The first and second directions intersect, so the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111 are sequentially connected to form a corrugated structure. Since multiple heater units A are connected in series, the first part 1111 and the fourth part 1114 of adjacent heater units A are connected. As a result, the heater region 1110 forms a continuous corrugated structure. Note that this connection means that the parts are joined together to form a single unit. For example, the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111 may be integrally molded, and multiple heater units A also constitute an integrally molded structure.

[0029] The second direction is defined as the extension direction of the graphite film 1100, and therefore, along the extension direction of the graphite film 1100, at least a portion of the graphite film 1100 forms a continuous corrugated structure. In the extension direction of the graphite film 1100, there are portions of the graphite film 1100 that extend in different directions (the fourth portion 1114 and the second portion 1112 extend in the same direction, and the third portion 1113 and the first portion 1111 extend in the same direction). This allows the graphite film 1100 to secure a large heater area within a limited space (extension length of the graphite film 1100) while avoiding a decrease in resistance.

[0030] As mentioned above, along the extension direction of the graphite film 1100, the heater region 1110 can form a continuous corrugated structure. If the dimensional design of the heater region 1110 is unreasonable, the heater region 1110 of the graphite film 1100 will be prone to rupture during the drop test of the heater core 1000, affecting the use of the heater core 1000. For example, the heater core 1000 is assembled with other parts to form a heater tube 2000 (details will be described later), and the test is performed by horizontally dropping the heater tube 2000 from a height of 25 cm onto a 10 mm thick rubber plate. During a drop test, vibrations are transmitted to the heater core 1000, and the heater core 1000 extends along the second direction for a certain length. As a result, the heater core 1000 oscillates along the second direction, and the fourth part 1114 and the second part 1112 extend along the second direction. Consequently, stress is concentrated mainly in the fourth part 1114 and the second part 1112, particularly at the intersections of the fourth part 1114 and the third part 1113, the fourth part 1114 and the first part 1111, the second part 1112 and the first part 1111, and the second part 1112 and the third part 1113, making them prone to fracture. Therefore, in this embodiment, in order to improve the vibration resistance of the heater core 1000 and reduce the risk of breakage of the heater core 1000, the width of the fourth portion 1114 is designed to be at least 2% of the width of the graphite film 1100, for example, if the width of the graphite film 1100 is d0 and the width of the fourth portion 1114 is d iWe define (i=4), satisfying d4 / d0≧2%, and correspondingly, the width of the third part 1113 is d i Let (i=3), satisfy d3 / d0≧2%, and the width of the second part 1112 be d i Let (i=2), satisfy d2 / d0≧2%, and the width of the first part 1111 is d i Let (i=1), satisfy d1 / d0≧2%, and all four parts are d i The setting / d0≧2% must be satisfied, and by setting it in this way, the vibration resistance of the heater core 1000 is increased, the heater core 1000 has sufficient strength, and fracture of the heater region 1110 due to stress concentration can be avoided. Also, d i By designing the width of the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111 to be at least 2% of the width of the graphite film 1100, the widths of the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111 are not too small, which reduces the difficulty of manufacturing.

[0031] Note that the so-called width is relative to the length, as shown in Figure 2. The width is shorter than the length, d4, d3, d2, and d1 are the widths of the fourth section 1114, the third section 1113, the second section 1112, and the first section 1111, respectively. The width direction of the fourth section 1114, the third section 1113, the second section 1112, and the first section 1111 is approximately perpendicular to the direction of current flow. L4, L3, L2, and L1 are the lengths of the fourth section 1114, the third section 1113, the second section 1112, and the first section 1111, respectively. The length direction of the fourth section 1114, the third section 1113, the second section 1112, and the first section 1111 is approximately the same direction as the direction of current flow. d0 is the width of the graphite film 1100, and the width direction of the graphite film 1100 is the first direction.

[0032] Furthermore, d i The width of the fourth part 1114 must be designed so as not to exceed 20% of the width of the graphite film 1100, that is, the width of the fourth part 1114 must be d i Let (i=4), satisfying d4 / d0≦20%, and correspondingly, the width of the third part 1113 is d i Let (i=3), satisfy d3 / d0≦20%, and the width of the second part 1112 is di Let (i=2), satisfy d2 / d0≦20%, and the width of the first part 1111 is d i By setting (i=1) and satisfying d1 / d0≦20%, we avoid a decrease in resistance due to an excessively large area through which current flows. This prevents the total power of the heater core 1000 from being too high, which would affect the lifespan of the graphite film 1100. As can be understood from the above, by optimizing the width and length of the four parts of the heater unit A (fourth part 1114, third part 1113, second part 1112, and first part 1111), both the heating efficiency and structural strength of the heater core 1000 are achieved.

[0033] As can be understood from the above, in the technical solution of the present application, d i The fact that / d0≧2% reduces the difficulty of the manufacturing process of the heater core 1000, improves the structural strength of the heater core 1000, and ensures the drop resistance of the heater core 1000, making the heater core 1000 less likely to break or deform, and furthermore, d i By having / d0 ≤ 20%, excessive total power due to low resistance is avoided, and consequently, excessive power density in the heater region 1110 of the graphite film 1100 is avoided, thereby improving the service life of the heater core 1000.

[0034] In some embodiments of the present invention, the width d0 of the graphite film 1100 is designed to be in the range of 5 mm to 20 mm, and may be 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm, or 20 mm. This ensures that the graphite film 1100 has an appropriate width, without being too wide which would affect its strength, nor too narrow which would make it difficult to process the aforementioned multiple heater units A. The heater core 1000 needs to be attached to the outer tube 2300 to form the heater tube 2000, and by designing the width d0 of the graphite film 1100 to be in a reasonable range, it is possible to avoid the radial dimension of the outer tube 2300 being too large which would occupy space in the corresponding equipment.

[0035] In some embodiments of this application, d i The possible range is designed to be 0.1mm to 4mm, and may be 0.1mm, 0.3mm, 0.6mm, 1.9mm, 2.4mm, 2.8mm, 3.2mm, 3.5mm, 3.8mm, or 4mm. i By designing it within a reasonable range, the manufacturing of the heater unit A becomes easier, and the large area of ​​the current flow cross-sections of the fourth part 1114, third part 1113, second part 1112, and first part 1111 prevents the resistance from decreasing, thereby preventing the total power of the heater core 1000 from being too high, which would affect its lifespan and consequently the lifespan of the outer tube 2300.

[0036] In some embodiments of the present application, referring to Figure 2, the area of ​​heater unit A is S, for example, the area S of heater unit A can be obtained by calculating the areas of the fourth part 1114, the third part 1113, the second part 1112, and the first part 1111, respectively, where S = d1*L1 + d2*L2 + d3*L3 + d4*L4, the power of heater unit A is P, and the power density of heater unit A is P d And P d =P / S and P d The power density P satisfies ≤70W / cm2, and through numerous tests by the inventors, it was confirmed that when the power density does not exceed 70W / cm2 at the rated voltage, for example at 110V or 220V, both the cooking effect of the food and the lifespan of the heater core 1000 can be ensured, thus avoiding excessive wear and damage to the heater core 1000. d The total power P of the heater core 1000 総 It can be calculated from, for example, if there are n heater units A, P 総 =nP.

[0037] Referring to Figure 3, in some embodiments of the present invention, in order to further enhance the vibration resistance of the graphite film 1100, the intersection of the fourth portion 1114 and the third portion 1113 is configured to be connected in an arc shape, the intersection of the third portion 1113 and the second portion 1112 is configured to be connected in an arc shape, the intersection of the second portion 1112 and the first portion 1111 is configured to be connected in an arc shape, and the intersection of the fourth portion 1114 and the first portion 1111 of two adjacent heater units A is also configured to be connected in an arc shape. This makes it possible to alleviate stress concentration.

[0038] As described above, since the heater core 1000 extends along the second direction for a constant length, the heater core 1000 oscillates along the second direction, and stress concentrates mainly in the fourth part 1114 and the second part 1112, and especially at the intersections of the fourth part 1114 and the third part 1113, the fourth part 1114 and the first part 1111, the second part 1112 and the first part 1111, and the second part 1112 and the third part 1113. By designing the heater unit A to connect at the intersections of each part (fourth part 1114, third part 1113, second part 1112 and first part 1111) in an arc shape, stress is distributed, fracture at the intersections is avoided, vibration resistance is increased, and the service life is further extended.

[0039] Referring to Figure 2, in some embodiments of the present application, the first direction is perpendicular to the second direction, that is, the fourth portion 1114 and the second portion 1112 extend substantially along the extending direction of the graphite film 1100, while the third portion 1113 and the first portion 1111 extend substantially perpendicular to the second direction. This facilitates the structural fabrication of the fourth portion 1114, the third portion 1113, the second portion 1112, and the first portion 1111 in the heater unit A, resulting in a more stable overall structure and maximum utilization of space.

[0040] Referring to Figure 2, in some embodiments of the present application, there are two heater regions 1110, which are defined as the first heater region 1110 and the second heater region 1110, with the heater region 1110 located on the left in Figure 2 being the first heater region 1110 and the heater region 1110 located on the right being the second heater region 1110. The graphite film 1100 further includes an intermediate region 1120, which is provided between the first heater region 1110 and the second heater region 1110, and is connected to both the first and second heater regions 1110. The intermediate region 1120 provides an electrical connection between the first and second heater regions 1110 and plays a role in current transmission. By providing the intermediate region 1120, the first and second heater regions 1110 are isolated, thus avoiding excessive heat concentration. When the heater core 1000 radiates heat into the cavity, the temperature of the inner cavity near the center of the heater core 1000 is high. Therefore, by designing an intermediate region 1120 to isolate the first heater region 1110 and the second heater region 1110, the heat radiated from the heater core 1000 is made more uniform. Furthermore, by providing the intermediate region 1120, the length of the intermediate region 1120 can be adjusted according to different scenarios, and the lengths of the first heater region 1110 and the second heater region 1110 can be adaptively changed to achieve dynamic distribution in response to power changes.

[0041] Referring to Figure 2, in some embodiments of the present application, the graphite film 1100 further includes a connection region 1130, the connection region 1130 located at the end of the graphite film 1100, the installation of the connection region 1130 enables an electrical connection between the heater core 1000 and an external component, for example, the installation of the connection region 1130 provides a support point for a fixed lead wire 2200, the lead wire 2200 is fixed to the connection region 1130, and the other end of the lead wire 2200 can be connected to another component (e.g., a connection terminal 2100), and the graphite film The area located at one end of the film 1100 is defined as the first connection area 1130, and the area located at the other end of the graphite film 1100 is defined as the second connection area 1130. Referring to Figure 2, the connection area 1130 located on the left is the first connection area 1130, and the connection area 1130 located on the right is the second connection area 1130. The first connection area 1130 is adjacent to the first heater area 1110, and the second connection area 1130 is adjacent to the second heater area 1110. By installing the connection areas 1130, power can be easily supplied to the heater core 1000.

[0042] In some embodiments, the graphite film 1100 radiates heat mainly through a heater region 1110, the heater region 1110 includes multiple heater units A, and the total resistance of the heater region 1110 can be calculated by summing the resistances of each heater unit A. Specifically, Let the resistance of the fourth section 1114 be R4, and R4 satisfies R4 = ρL4 / (σd4). Let the resistance of the third part 1113 be R3, and R3 satisfies R3 = ρL3 / (σd3). Let the resistance of the second part 1112 be R2, and R2 satisfies R2 = ρL2 / (σd2). Let R1 be the resistor of the first part 1111, and R1 satisfies R1 = ρL1 / (σd1). The resistance of heater unit A is R = R4 + R3 + R2 + R1, and the total resistance of graphite film 1100 is R 総 =nR.

[0043] Here, ρ is the resistivity and σ is the thickness of the graphite film 1100. In this application, the number n of heater units A is not limited, and those skilled in the art may design the number of n according to the practical needs to satisfy the heat generation requirements.

[0044] For example, the graphite film 1100 has a length of 240 nm, a width (d0) of 8 mm, a thickness (σ) of 0.2 mm, a resistivity (ρ) of 0.00029 Ω·cm, d1, d2, d3, and d4 are 1.6 mm, L1 and L3 are 6.8 mm each, L2 and L4 are 3.8 mm each, H1 and H2 are 16.5 mm, and H1 and H2 are the lengths of the first and second connection regions 1130, respectively. Designing the resistance value to be 9 Ω, the resistance value of heater unit A can be divided into R1, R2, R3, and R4. By calculation, R1 and R3 are 0.061625, and R2 and R4 are 0.034438, so the resistance R of heater unit A is 0.192125. Designing the number n of heater units A to be 47, the total resistance R 総 This becomes 9.029875.

[0045] A second aspect of the present application further discloses a heater tube 2000, which includes the heater core 1000 of the above embodiment, wherein the heater core 1000 of the heater tube 2000 of this embodiment employs the technical solution of the above embodiment, and therefore has at least the beneficial effects of the technical solution of the above embodiment, including, but not limited to, the effect of reducing the difficulty of the manufacturing process of the heater core 1000, improving the structural strength of the heater core 1000, ensuring the drop resistance of the heater core 1000 so that the heater core 1000 is less likely to break or deform, and further, avoiding excessive total power due to low resistance, and consequently avoiding excessive power density in the heater region 1110 of the graphite film 1100, thereby improving the service life of the heater core 1000.

[0046] Specifically, the heater tube 2000 includes the heater core 1000, outer tube 2300, lead wires 2200, and connection terminals 2100, where the outer tube 2300 may be a glass tube, the heater core 1000 is drilled inside the outer tube 2300, both ends of the graphite film 1100 of the heater core 1000 are connected to the lead wires 2200, and connection terminals 2100 are provided at both ends of the outer tube 2300, the lead wires 2200 are connected to the connection terminals 2100, and the connection terminals 2100 are suitable for connection to other power supply components. Selectively, the inside of the outer tube 2300 is filled with an inert gas, which may be helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), etc. When the heater core 1000 is energized, the graphite film 1100 is in a high-temperature, heat-generating state. By filling it with an inert gas, protection for the graphite film 1100 can be achieved, and the service life of the graphite film 1100 can be extended.

[0047] A third aspect of the present application further discloses a home appliance, which includes the heater tube 2000 of the above embodiment, and the home appliance may be an appliance that needs to be heated, such as an electric oven, microwave oven, or steam oven. The heater tube 2000 of the home appliance in this embodiment employs the heater tube 2000 of the above embodiment and therefore has at least the beneficial effects brought about by the technical solution of the above embodiment, and a redundant explanation is omitted here.

[0048] The above description is merely a preferred embodiment of the present application and does not limit the scope of the claims of the present application. Equivalent structural transformations based on the concept of the present application and utilizing the contents of the specification and drawings of the present application, or their direct or indirect application to other related technical fields, are all within the scope of the patent protection of the present application.

Claims

1. Including graphite film, The graphite film includes a heater region, the heater region includes a plurality of series-connected heater units, the heater units include sequentially connected first, second, third and fourth parts, two adjacent heater units are connected via the first and fourth parts, the first and third parts extend along a first direction, the second and fourth parts extend along a second direction, the second direction is the direction in which the graphite film extends and intersects the first direction. The width of the graphite film is d ０ The widths of the first, second, third, and fourth parts are each d １ d ２ d ３ and d ４ Therefore, 2% ≤ d ｉ / d ０ A heater core that satisfies ≤20%, where i is 1, 2, 3, or 4.

2. d ０ The heater core according to claim 1, wherein the diameter is 5 mm to 20 mm.

3. d ｉ The heater core according to claim 1, wherein d is 0.1 mm to 4 mm.

4. The area of ​​the heater unit is S, the power of the heater unit is P, and the power density is P ｄ = P / S, and P ｄ ≤70 W / cm ２ A heater core according to claim 1, satisfying the requirements.

5. The heater core according to any one of claims 1 to 4, wherein the first part and the second part are connected in an arc shape, the second part and the third part are connected in an arc shape, the third part and the fourth part are connected in an arc shape, and the fourth part and the first part are connected in an arc shape.

6. The heater core according to claim 1, wherein the second direction is orthogonal to the first direction.

7. The heater core according to claim 1, wherein the graphite film includes an intermediate region, and there are two heater regions, the intermediate region being connected to the heater region and located between the two intermediate regions.

8. The heater core according to claim 1 or 7, wherein the graphite film further includes connection regions located at both ends, the connection regions being connected to the heater region, and the connection regions being suitable for connection to lead wires.

9. A heater tube comprising a heater core according to any one of claims 1 to 8.

10. The heater tube according to claim 9, wherein the heater tube further includes an outer tube, the heater core is provided inside the outer tube, and the inside of the outer tube is filled with an inert gas.

11. A home appliance comprising a heater tube as described in claim 9 or 10.

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