Heating core, heating tube and household appliance

Abstract

This application discloses a heating core, a heating tube, and a household appliance. The heating core includes a graphite film, which includes a heating area. The heating area includes multiple heating units connected in series. Each heating unit includes a first part, a second part, a third part, and a fourth part connected in sequence. Adjacent heating units are connected through the first part and the fourth part. The first and third parts extend along a first direction, and the second and fourth parts extend along a second direction, which is the extension direction of the graphite film and intersects with 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, satisfying 2% ≤ d0. i / d0≤20%, where i is 1, 2, 3, 4. Through d i / d0≥2%, improve the structural strength of the heating element and ensure its drop resistance; d i / d0≤20% can avoid excessive power density in the heating zone of the graphite film due to low resistance, thus improving the service life of the heating core.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of household appliances, in particular to a heating core, a heating tube and a household appliance. BACKGROUND

[0002] Traditional electric ovens mainly heat the air in the cavity through heating elements and then heat the food, and directly heat the surface of the food through heat radiation. The heating elements in the electric ovens / microwave ovens / steam ovens and other appliances on the market mainly include metal heating tubes or quartz heating tubes. However, the existing heating tubes have low heating efficiency, cannot effectively concentrate energy, have slow temperature rise speed, lengthen cooking time, and it is difficult to achieve the well-done outside and tender inside of food during the baking process, thereby reducing the user experience. A graphite heating core appears in the related art to solve the above problems, but the existing graphite heating core still needs to be improved. SUMMARY

[0003] The present application aims to at least partially solve the technical problems in the related art. To this end, the present application provides a heating core.

[0004] To achieve the above-mentioned purpose, the present application discloses a heating core, which comprises:

[0005] The graphite film material comprises a heating area, and the heating area comprises a plurality of series-connected heating units. The heating unit comprises a first part, a second part, a third part and a fourth part connected in sequence. Two adjacent heating units are connected by the first part and the fourth part. The first part and the third part extend along a first direction, and the second part and the fourth part extend along a second direction. The second direction is the extension direction of the graphite film material and intersects the first direction.

[0006] The width of the graphite film material is d0, and the widths of the first part, the second part, the third part and the fourth part are d1, d2, d3 and d4 respectively, which satisfy 2%≤d i / d0≤20%, where i is 1, 2, 3 or 4.

[0007] In some embodiments of the present application, d0 is 5mm-20mm.

[0008] In some embodiments of the present application, d i is 0.1mm-4mm.

[0009] In some embodiments of the present application, the area of the heating unit is S, the power of the heating unit is P, and the power density is P d =P / S, which satisfies P d ≤70W / cm 2 .

[0010] In some embodiments of the present application, the first portion and the second portion are arc-shapedly connected, the second portion and the third portion are arc-shapedly connected, the third portion and the fourth portion are arc-shapedly connected, and the fourth portion and the first portion are arc-shapedly connected.

[0011] In some embodiments of the present application, the second direction is perpendicular to the first direction.

[0012] In some embodiments of the present application, the graphite film material comprises an intermediate region, and the heating region comprises two, the intermediate region is connected with the heating region and located between the two intermediate regions.

[0013] In some embodiments of the present application, the graphite film material further comprises a connecting region at both ends, the connecting region is connected with the heating region, and the connecting region is suitable for connecting with a lead wire.

[0014] The present application also discloses a heating tube, comprising the heating core.

[0015] In some embodiments of the present application, the heating tube further comprises an outer tube, the heating core is arranged in the inner part of the outer tube, and the inner part of the outer tube is filled with inert gas.

[0016] The present application also discloses a household appliance, comprising the heating tube.

[0017] In the technical scheme of the present application, d i d0≥2%, so as to reduce the manufacturing process difficulty of the heating core, improve the structural strength of the heating core, ensure the drop resistance of the heating core, and prevent the heating core from being easily broken or deformed; in addition, d i d0≤20%, so as to avoid that the total power is too large due to the small resistance, and further avoid that the power density of the heating region of the graphite film material is too large, and improve the service life of the heating core.

[0018] Other advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other designs according to the structures shown in the drawings without creative labor.

[0020] Figure 1 The schematic diagram of the heating tube in some embodiments of the present application;

[0021] Figure 2 A schematic diagram of a heating core in some embodiments of the present application;

[0022] Figure 3 A schematic diagram of a heating core in some embodiments of the present application.

[0023] Explanation of reference signs:

[0024] Heating core 1000, graphite film material 1100, heating area 1110, heating unit A, first part 1111, second part 1112, third part 1113, fourth part 1114, middle area 1120, connecting area 1130;

[0025] Heating tube 2000, connecting terminal 2100, lead wire 2200, outer tube 2300.

[0026] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise of the present application, all belong to the scope of protection of the present application.

[0028] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0029] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through intermediate medium, can be internal communication of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0031] The present application provides a heating core 1000, which combines Figure 1 and Figure 2 As shown in the drawings, in some embodiments of the present application, the heating core 1000 comprises a graphite film material 1100, which needs to meet the condition d i / d0≥2%, so as to reduce the manufacturing process difficulty of the heating core 1000, improve the structural strength of the heating core 1000, ensure the drop resistance of the heating core 1000, so that the heating core 1000 is not easy to break or deform; In addition, it also needs to meet d i / d0≤20%, which can avoid the total power being too large due to the small resistance, thereby avoiding the power density of the heating area 1110 of the graphite film material 1100 being too large, and improving the service life of the heating core 1000.

[0032] Specifically, the main component of the graphite film material 1100 is prepared from graphite, which constitutes a flat structure, so as to form surface heating, so it has higher heating efficiency, higher corresponding speed and faster heating speed compared with traditional heating wire, so that the energy is more concentrated, and the effect of outer crisp and inner tender of food roasting is realized.

[0033] Generally, the heating core 1000 needs to extend in a certain direction for a certain length, and since the graphite film material 1100 constitutes a surface heating, in order to form a larger heating area in a limited length, the graphite film material 1100 includes a heating area 1110, and the graphite film material 1100 mainly emits heat through the heating area 1110. The heating area 1110 includes a plurality of heating units A, and the plurality means two or more. The plurality of heating units A are connected in series, that is, the current flowing through each heating unit A is consistent. The heating unit A includes four parts, that is, a fourth part 1114, a third part 1113, a second part 1112 and a first part 1111. The third part 1113 and the first part 1111 extend in a first direction for a certain length, and the fourth part 1114 and the second part 1112 extend in a second direction for a certain length. The first direction and the second direction intersect, so that the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 are sequentially connected to form a relief structure. Since the plurality of heating units A are connected in series, the first part 1111 and the fourth part 1114 of adjacent heating units A are connected together, so that the heating area 1110 constitutes a continuous relief structure. It can be understood that the connection here means combination, for example, the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 can be integrally formed, and the plurality of heating units A also constitute an integrally formed structure.

[0034] The second direction is defined as the extension direction of the graphite film material 1100, so that at least part of the graphite film material 1100 constitutes a continuous relief structure along the extension direction of the graphite film material 1100. Since in the extension direction of the graphite film material 1100, the graphite film material 1100 has parts extending in different directions (the fourth part 1114 and the second part 1112 extend in the same direction, and the third part 1113 and the first part 1111 extend in the same direction), so that in a limited space (the extension length of the graphite film material 1100), the graphite film material 1100 can have a larger heating area without reducing the resistance.

[0035] As mentioned above, along the extending direction of the graphite film material 1100, the heat generating area 1110 can form a continuous undulating structure. If the size of the heat generating area 1110 is not properly designed, it is easy to cause the heat generating area 1110 of the graphite film material 1100 to break during the drop test of the heat generating core 1000, affecting the use of the heat generating core 1000. For example, the heat generating core 1000 is assembled with other components to form a heat generating tube 2000 (to be described below), and the heat generating tube 2000 is tested by being horizontally dropped from a height of 25 cm onto a rubber plate with a thickness of 10 mm. During the drop test, the vibration is transmitted to the heat generating core 1000. Since the heat generating core 1000 extends a certain length along the second direction, the heat generating core 1000 will swing along the second direction. Since the fourth portion 1114 and the second portion 1112 extend along the second direction, stress will mainly concentrate on the fourth portion 1114 and the second portion 1112, especially at the intersection of the fourth portion 1114 and the third portion 1113, the intersection of the fourth portion 1114 and the first portion 1111, the intersection of the second portion 1112 and the first portion 1111, the intersection of the second portion 1112 and the third portion 1113, which is easy to cause breakage. Therefore, in the present embodiment, in order to enhance the anti-vibration ability of the heat generating core 1000 and reduce the risk of breakage of the heat generating core 1000, the width of the fourth portion 1114 is designed to be at least 2% of the width of the graphite film material 1100. For example, the width of the graphite film material 1100 is defined as d0, and the width of the fourth portion 1114 is d4 i (i = 4), satisfying d4 / d0≥2%, correspondingly, the width of the third portion 1113 is d3 i (i = 3), satisfying d3 / d0≥2%, the width of the second portion 1112 is d2 i (i = 2), satisfying d2 / d0≥2%, the width of the first portion 1111 is d1 i (i = 1), satisfying d1 / d0≥2%, all the four portions need to satisfy d i The above setting can enhance the anti-vibration ability of the heat generating core 1000, so that the heat generating core 1000 has sufficient strength to avoid breakage of the heat generating area 1110 due to stress concentration. Moreover, the width of the fourth portion 1114 is designed to be at least 2% of the width of the graphite film material 1100, which can prevent the width of the fourth portion 1114, the third portion 1113, the second portion 1112 and the first portion 1111 from being too small and reducing the manufacturing difficulty. i

[0036] It can be understood that the so-called width is relative to the length, and the above Figure 2 ​As shown, the width is less than the length, d4, d3, d2 and d1 are the widths of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 respectively, the width direction of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 is substantially perpendicular to the flow direction of the current, L4, L3, L2 and L1 are the lengths of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 respectively, the length direction of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 is substantially the same as the flow direction of the current, and d0 is the width of the graphite film material 1100, the width direction of the graphite film material 1100 is the first direction.

[0037] In addition, d i is required to be designed to be not greater than 20% of the width of the graphite film material 1100, that is, the width of the fourth part 1114 is d i (i=4), and d4 / d0≤20% is satisfied, correspondingly, the width of the third part 1113 is d i (i=3), and d3 / d0≤20% is satisfied, the width of the second part 1112 is d i (i=2), and d2 / d0≤20% is satisfied, and the width of the first part 1111 is d i (i=1), and d1 / d0≤20% is satisfied, so as to avoid excessive current flow area and reduce resistance, thereby avoiding excessive total power of the heating core 1000 and affecting the service life of the graphite film material 1100. As can be seen from the above, by optimizing the width and length of the four parts (the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111) of the heating unit A, the heating efficiency and structural strength of the heating core 1000 are considered.

[0038] As can be seen from the above, in the technical scheme of the present application, d i / d0≥2%, so as to reduce the manufacturing process difficulty of the heating core 1000, improve the structural strength of the heating core 1000, ensure the drop resistance of the heating core 1000, so that the heating core 1000 is not easy to break or deform; in addition, d i / d0≤20%, which can avoid excessive total power caused by small resistance, and further avoid excessive power density of the heating area 1110 of the graphite film material 1100, thereby improving the service life of the heating core 1000.

[0039] In some embodiments of the present application, the width d0 of the graphite film material 1100 is designed to be in the range of 5mm to 20mm, which can be 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 20mm, so that the graphite film material 1100 has a suitable width, which will not affect the strength due to too large width, and will not be difficult to process the plurality of heating units A due to too small width. It can be understood that the heating core 1000 needs to be installed into the outer tube 2300 to form the heating tube 2000, and the width d0 of the graphite film material 1100 is designed to be in a reasonable range to avoid the radial size of the outer tube 2300 being too large to occupy the space of the corresponding equipment.

[0040] In some embodiments of the present application, d i is designed to be in the range of 0.1mm to 4mm, which can be 0.1mm, 0.3mm, 0.6mm, 1.9mm, 2.4mm, 2.8mm, 3.2mm, 3.5mm, 3.8mm, 4mm. By designing d i to be in a reasonable range, the heating unit A can be easily processed, and at the same time, the area of the current flow cross section of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 is not too large to reduce the resistance, thereby avoiding the total power of the heating core 1000 being too high to affect the service life, and even affecting the service life of the outer tube 2300.

[0041] In some embodiments of the present application, as shown in Figure 2 , the area of the heating unit A is S, for example, the area S of the heating unit A can be calculated by calculating the area of the fourth part 1114, the third part 1113, the second part 1112 and the first part 1111 respectively, S=d1*L1+d2*L2+d3*L3+d4*L4, the power of the heating unit A is P, the power density of the heating unit A is P d , P d =P / S, and P d satisfies ≤70W / cm 2 . Through a large number of experiments of the inventor, it is found that under the rated voltage, for example, 110V or 220V, the power density is not higher than 70W / cm 2 , which can balance the baking effect of the food and ensure the service life of the heating core 1000, and avoid the rapid wear of the heating core 1000 to damage. It can be understood that the power density P d can be calculated by the total power P 总 of the heating core 1000, for example, the heating unit A has n, then P 总 =nP.

[0042] In combination with Figure 3As shown, in some embodiments of the present application, in order to further improve the anti-vibration capability of the graphite film material 1100, the intersection of the fourth portion 1114 and the third portion 1113 forms an arc-shaped transition, the intersection of the third portion 1113 and the second portion 1112 forms an arc-shaped transition, the intersection of the second portion 1112 and the first portion 1111 forms an arc-shaped transition, and the intersection of the fourth portion 1114 and the first portion 1111 of the adjacent two heating units A also forms an arc-shaped transition, so as to reduce stress concentration,

[0043] As mentioned above, since the heating core 1000 extends along the second direction for a certain length, the heating core 1000 will swing along the second direction, resulting in stress mainly concentrated in the fourth portion 1114 and the second portion 1112, especially concentrated in the intersection of the fourth portion 1114 and the third portion 1113, the intersection of the fourth portion 1114 and the first portion 1111, the intersection of the second portion 1112 and the first portion 1111, and the intersection of the second portion 1112 and the third portion 1113. By designing the intersection of the portions (the fourth portion 1114, the third portion 1113, the second portion 1112, and the first portion 1111) of the heating unit A to be arc-shaped transition, the stress is dispersed, the intersection is prevented from breaking, the anti-vibration capability is improved, and the service life is further improved.

[0044] In combination with Figure 2 As shown, in some embodiments of the present application, the first direction and the second direction are perpendicular, that is, the fourth portion 1114 and the second portion 1112 extend substantially along the extension direction of the graphite film material 1100, and the third portion 1113 and the first portion 1111 extend substantially perpendicular to the second direction, so as to facilitate the structural processing of the fourth portion 1114, the third portion 1113, the second portion 1112, and the first portion 1111 in the heating unit A, the overall structure is more stable, and the space can be maximized.

[0045] In combination with Figure 2 As shown, in some embodiments of the present application, the heating area 1110 includes two, and the two heating areas 1110 are defined as a first heating area 1110 and a second heating area 1110, Figure 2The left heat area 1110 is a first heat area 1110, the right heat area 1110 is a second heat area 1110, the graphite film material 1100 further comprises an intermediate area 1120, the intermediate area 1120 is arranged between the first heat area 1110 and the second heat area 1110, and the intermediate area 1120 is connected with the first heat area 1110 and the second heat area 1110, the intermediate area 1120 realizes electrical connection with the first heat area 1110 and the second heat area 1110, plays a role in transmitting current, and the arrangement of the intermediate area 1120 separates the first heat area 1110 and the second heat area 1110, avoiding excessive concentration of heat. Since the inner cavity temperature near the middle of the heating core 1000 is high when the heating core 1000 radiates heat, the first heat area 1110 and the second heat area 1110 are separated by the design of the intermediate area 1120, so that the heat radiated by the heating core 1000 is more uniform. In addition, by arranging the intermediate area 1120, the length of the intermediate area 1120 can be adjusted according to different scenes, so that the length of the first heat area 1110 and the second heat area 1110 adapts to changes, thereby realizing dynamic allocation of power changes.

[0046] In combination Figure 2 As shown in the drawings, in some embodiments of the present application, the graphite film material 1100 further comprises a connecting area 1130, the connecting area 1130 is located at the end of the graphite film material 1100, and the arrangement of the connecting area 1130 realizes electrical connection with the heating core 1000 and external components, for example, the arrangement of the connecting area 1130 provides a support point for the fixed lead 2200, the lead 2200 can be fixed on the connecting area 1130, and the other end of the lead 2200 can be connected with another component (for example, a connecting terminal 2100), and the connecting area 1130 located at one end of the graphite film material 1100 is defined as a first connecting area 1130, and the connecting area 1130 located at the other end of the graphite film material 1100 is defined as a second connecting area 1130. Figure 2 As shown in the drawings, the left connecting area 1130 is a first connecting area 1130, and the right connecting area 1130 is a second connecting area 1130, the first connecting area 1130 is adjacent to the first heat area 1110, and the second connecting area 1130 is adjacent to the second heat area 1110, and the arrangement of the connecting area 1130 facilitates the realization of power supply of the heating core 1000.

[0047] In some embodiments, the graphite film material 1100 mainly radiates heat through the heat area 1110, and the heat area 1110 comprises a plurality of heating units A, and the total resistance of the heat area 1110 can be calculated by adding the resistances of the heating units A.

[0048] The resistance of the fourth part 1114 is R4, and R4 satisfies R4 = pL4 / (s d4);

[0049] The resistance of the third part 1113 is R3, and R3 satisfies R3 = pL3 / (s d3);

[0050] The resistance of the second part 1112 is R2, and R2 satisfies R2 = pL2 / (s d2);

[0051] The resistance of the first part 1111 is R1, and R1 satisfies R1 = pL1 / (s d1);

[0052] The resistance R of the heating unit A is R = R4 + R3 + R2 + R1, and the total resistance R of the graphite film material 1100 is R = nR. 总 = nR.

[0053] Wherein, p is the resistivity, s is the thickness of the graphite film material 1100. It can be understood that in the present application, the number n of the heating unit A is not limited, and those skilled in the art can design the number n according to the actual demand to meet the heating demand.

[0054] For example, the length of the graphite film material 1100 is 240mm; the width (d0) is 8mm; the thickness (s) is 0.2mm; the resistivity (p) is 0.00029Ω·cm; d1, d2, d3, d4 is 1.6mm; L1, L3 is 6.8mm respectively; L2, L4 is 3.8mm respectively; H1, H2 is 16.5mm, H1 and H2 are the length of the first connecting area 1130 and the second connecting area 1130 respectively. The designed resistance value is 9Ω, the resistance value of the heating unit A can be divided into R1, R2, R3, R4, and R1 and R3 are calculated to be 0.061625, R2 and R4 are calculated to be 0.034438, the resistance R of the heating unit A is 0.192125, and the number n of the heating unit A is designed to be 47. The total resistance R 总 is 9.029875.

[0055] The second aspect of the present application also discloses a heating pipe 2000, which comprises the heating core 1000 of the above-mentioned embodiment. It can be understood that the heating core 1000 of the heating pipe 2000 of the present embodiment adopts the technical solutions of the above-mentioned embodiments, and therefore at least has the beneficial effects brought by the technical solutions of the above-mentioned embodiments, including but not limited to reducing the manufacturing process difficulty of the heating core 1000, improving the structural strength of the heating core 1000, ensuring the drop resistance of the heating core 1000, making the heating core 1000 not easy to break or deform, and also avoiding that the total power is too large due to the small resistance, thereby avoiding that the power density of the heating area 1110 of the graphite film material 1100 is too large, and improving the service life of the heating core 1000.

[0056] Specifically, the heating tube 2000 comprises the above-mentioned heating core 1000, an outer tube 2300, a lead wire 2200 and a connecting terminal 2100, wherein the outer tube 2300 can be a glass tube, the heating core 1000 is arranged in the inner part of the outer tube 2300, the two ends of the graphite film material 1100 of the heating core 1000 are connected with the lead wire 2200 respectively, the two ends of the outer tube 2300 are provided with the connecting terminal 2100 respectively, the lead wire 2200 is connected with the connecting terminal 2100, and the connecting terminal 2100 is suitable for being connected with other power supply components. Optionally, the inner part of the outer tube 2300 is filled with inert gas, which can be helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) or the like. Since the graphite film material 1100 is in a high-temperature heating state when the heating core 1000 is powered on, the graphite film material 1100 can be protected by the inert gas, thereby prolonging the service life of the graphite film material 1100.

[0057] The third aspect of the present application also discloses a household appliance comprising the above-mentioned heating tube 2000, which can be an electric oven / microwave oven / steam oven or other equipment that needs to be heated. It can be understood that the heating tube 2000 of the household appliance of the present embodiment adopts the above-mentioned heating tube 2000, and thus at least has the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0058] The above-mentioned is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields based on the content of the present application and the drawings, or the like, which is within the concept of the present application, is included in the patent protection scope of the present application.

Claims

1. A heating element, characterized in that, include: A graphite film material includes a heating area, the heating area including multiple heating units connected in series, the heating unit including a first part, a second part, a third part and a fourth part connected in sequence, two adjacent heating units being connected through the first part and the fourth part, the first part and the third part extending along a first direction, the second part and the fourth part extending along a second direction, the second direction being the extension direction of the graphite film material and intersecting with the first direction; The width of the graphite film is d0, and the widths of the first part, the second part, the third part and the fourth part are d1, d2, d3 and d4 respectively, satisfying 2%≤di / d0<20%, ​​where i is 1, 2, 3 and 4; The area of ​​the heating element is S, the power of the heating element is P, and the power density is Pd = P / S, satisfying Pd ≤ 70 W / cm². 2 .

2. The heating element as described in claim 1, characterized in that, d0 is 5mm~20mm.

3. The heating element as described in claim 1, characterized in that, di ranges from 0.1mm to 4mm.

4. The heating element as described in any one of claims 1 to 3, characterized in that, The first part and the second part have an arc transition, the second part and the third part have an arc transition, the third part and the fourth part have an arc transition, and the fourth part and the first part have an arc transition.

5. The heating element as described in claim 1, characterized in that, The second direction is perpendicular to the first direction.

6. The heating element as described in claim 1, characterized in that, The graphite film includes an intermediate region, and the heating region includes two regions. The intermediate region is connected to the heating region and is located between the two intermediate regions.

7. The heating element as described in claim 1 or 6, characterized in that, The graphite film also includes connection areas at both ends, which are connected to the heating area and are adapted to be connected to leads.

8. A heating element, characterized in that, Includes the heating element as described in any one of claims 1 to 7.

9. The heating element as described in claim 8, characterized in that, The heating element also includes an outer tube, and the heating core is disposed inside the outer tube, the interior of which is filled with an inert gas.

10. A household appliance, characterized in that, Includes the heating element as described in claim 8 or 9.

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