Graphite heating tube and cooking equipment

Abstract

The invention discloses a graphite heating tube and cooking equipment, and the graphite heating tube comprises a hollow tube body, the tube body is provided with at least one bending part, the bending part is in a circular arc shape, and a reference line is defined to pass through the circle center of the bending part and is perpendicular to the radius direction of the bending part; the heating piece is formed into a sheet-shaped graphene material piece, the heating piece is arranged in the pipe body in a penetrating mode, in the thickness direction of the heating piece, the heating piece is provided with a neutral face located in the center, the neutral face extends in the length direction of the pipe body, and at least the part, right opposite to the bent part, of the neutral face is parallel to the reference line. According to the invention, the part, which is at least opposite to the bending part, of the neutral surface is parallel to the reference line, so that the heating piece cannot be twisted by external force, the heating piece can smoothly penetrate into the pipe body, the yield is improved, the production efficiency is greatly improved, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of cooking devices, and in particular to a graphite heating tube and a cooking device. Background Art

[0002] In the related art, a graphite heating tube is formed by vacuum encapsulating a graphite sheet into a quartz tube. However, the graphite sheet is relatively thin, and problems such as distortion and cracks are likely to occur during the process of inserting the graphite sheet into the bent quartz tube, resulting in a high defect rate. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a graphite heating tube, which improves the yield rate.

[0004] The graphite heating tube according to an embodiment of the present invention includes: a hollow tube body, the tube body having at least one bent portion, the bent portion being formed into an arc shape, a reference line being defined as passing through the center of the bent portion and being perpendicular to the radius direction of the bent portion; a heating element, the heating element being formed into a sheet-shaped graphene material piece, the heating element being inserted through the tube body, in the thickness direction of the heating element, the heating element having a neutral plane at the center, the neutral plane extending along the length direction of the tube body, and at least a part of the neutral plane facing the bent portion being parallel to the reference line.

[0005] According to the graphite heating tube of the embodiment of the present invention, by setting at least a part of the neutral plane facing the bent portion to be parallel to the reference line, the heating element is not distorted by external forces, so that the heating element can be smoothly inserted into the tube body, improving the yield rate, greatly improving the production efficiency, and saving costs.

[0006] In some embodiments, the radius of curvature of the central axis of the bent portion is R1, and the radius of curvature of the part of the neutral plane facing the bent portion is R2, where 0.95 ≤ (R2 / R1) ≤ 1.05.

[0007] In some embodiments, the heating element includes a plurality of heating units arranged in sequence along the length direction, each heating unit being formed into a bent section with an opening facing a first direction, and adjacent heating units being connected by a connecting piece.

[0008] In some embodiments, the connecting piece is connected to the end of the bent section.

[0009] In some embodiments, each heating unit includes two parallel heating side walls, the distance between the two heating side walls being a first distance, and the gap between adjacent heating units being a second distance, the first distance and the second distance being the same.

[0010] In some embodiments, the first spacing is 0.5 mm, and the thickness of the heating element ranges from 0.1 mm to 0.3 mm.

[0011] In some embodiments, the thickness of the heating element is 0.2 mm.

[0012] In some embodiments, the tube body is a circular tube.

[0013] In some embodiments, both ends of the heating element in the length direction are connected with connection terminals. Each connection terminal is press-sealed and fixed with the tube body, and a part of the connection terminal extends out of the tube body.

[0014] In some embodiments, the connection terminal includes a main body portion and a packaging portion. The main body portion is connected with the heating element. The packaging portion is connected with the main body portion and is press-sealed and fixed with the tube body. The main body portion and the packaging portion have an included angle.

[0015] In some embodiments, the main body portion and the packaging portion are perpendicularly arranged.

[0016] The cooking device according to an embodiment of the present invention includes the above-mentioned graphite heating tube.

[0017] The cooking device according to an embodiment of the present invention is provided such that at least a part of the neutral plane facing the bending portion is parallel to the reference line, so that the heating element will not be distorted by external forces, enabling the heating element to smoothly penetrate into the tube body, improving the yield rate, greatly improving the production efficiency, and saving costs.

[0018] In some embodiments, the cooking device includes: a box body, with a draw-out opening provided on the front side of the box body; a draw-out member for holding food, the draw-out member being drawable relative to the box body through the draw-out opening; and a graphite heating tube, the graphite heating tube being provided in the box body to heat the interior of the box body.

[0019] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0021] Figure 1 is a schematic diagram of the graphite heating tube in the first embodiment of the present invention, wherein the graphite heating tube is in a state of being ready for press-sealing;

[0022] Figure 2 is a schematic diagram of the shape of the tube body after press-sealing in the first embodiment of the present invention, wherein the tube body is partially cut open;

[0023] Figure 3 Schematic diagram of the curvature of the central axis of each part of the tube body in the embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the structure of the heating element in the embodiment of the present invention;

[0025] Figure 5 is Figure 4 Local enlarged view at I in

[0026] Figure 6 Schematic diagram of the sweeping path formed after the heating element is positioned in the tube body in the embodiment of the present invention;

[0027] Figure 7 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the present invention Figure 1 ;

[0028] Figure 8 is Figure 7 Local enlarged view at II in

[0029] Figure 9 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the present invention Figure 1 ;

[0030] Figure 10 is Figure 9 Local enlarged view at III in

[0031] Figure 11 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the present invention Figure 1 ;

[0032] Figure 12 is Figure 11 Local enlarged view at IV in

[0033] Figure 13 Explosion diagram of the graphite heating tube in the embodiment of the present invention;

[0034] Figure 14 Schematic diagram of the graphite heating tube in the second embodiment of the present invention, wherein the graphite heating tube is in a state of being ready for pressure sealing;

[0035] Figure 15 Schematic diagram of the shape of the graphite heating tube after pressure sealing in the second embodiment of the present invention, wherein a part of the tube body is sectioned;

[0036] Figure 16 Schematic diagram of the included angle θ in the embodiment of the present invention;

[0037] Figure 17 Schematic diagram of the cooperation between the heating element and the straight tube in the embodiment of the present invention;

[0038] Figure 18 For Figure 17 Partial enlarged view at V in

[0039] Figure 19 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the present invention Figure 2 ;

[0040] Figure 20 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the present invention Figure 3 ;

[0041] Figure 21 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the present invention Figure 2 ;

[0042] Figure 22 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the present invention Figure 3 ;

[0043] Figure 23 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the present invention Figure 2 ;

[0044] Figure 24 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the present invention Figure 3 。

[0045] Reference numerals:

[0046] 100, graphite heating tube;

[0047] 10, tube body; 11, bending part;

[0048] 20, heating element; 22, heating unit; 221, heating side wall; 23, connection terminal; 231, main body part; 232, encapsulation part;

[0049] F1, neutral plane; F2, pressing block; L1, first distance; L2, second distance. Detailed implementation manners

[0050] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0051] The graphite heating tube 100 of the embodiment of the present invention will be described below with reference to the drawings.

[0052] As Figure 1 shown, the graphite heating tube 100 according to the embodiment of the present invention includes: a tube body 10 and a heating element 20.

[0053] The tube body 10 is hollow, and the tube body 10 has at least one bent portion 11. The bent portion 11 is formed in an arc shape. A reference line is defined to pass through the center of the bent portion 11 and is perpendicular to the radial direction of the bent portion 11 of the tube body 10.

[0054] Among them, the reference line is a virtual line. In this application, the reference line is defined as a virtual line that passes through the center of the bent portion 11 and is perpendicular to the radial direction of the bent portion 11 of the tube body 10.

[0055] Specifically, the tube body 10 has at least one bent portion 11, and the bent portion 11 is formed in an arc shape. For example, the overall appearance shape of the tube body 10 is U-shaped, and the middle part of the U-shaped tube is an arc-shaped bent portion 11; or, the overall appearance shape of the tube body 10 is S-shaped, and multiple parts of the S-shaped tube are all arc-shaped; or, the overall appearance shape of the tube body 10 is ring-shaped, and all parts of the ring-shaped tube are arc-shaped.

[0056] The heating element 20 is formed as a sheet-shaped graphene material element. The heating element 20 is threaded through the tube body 10. In the thickness direction of the heating element 20, the heating element 20 has a neutral plane F1 located at the center. The neutral plane F1 extends along the length direction of the tube body 10, and at least the part of the neutral plane F1 facing the bent portion 11 is arranged parallel to the reference line.

[0057] Among them, the graphene material element itself has excellent heat conduction and heat dissipation capabilities. The graphite heating tube 100 of this application utilizes the capabilities of the graphene material element, so that the graphite heating tube 100 has the advantages of fast heating speed and strong radiation.

[0058] Among them, the neutral plane F1 is a virtual plane. In this application, the neutral plane F1 is defined as a virtual plane located at the center of the thickness direction of the heating element 20 and extending along the length direction of the tube body 10.

[0059] In the related art, the graphite heating tube is to vacuum-seal the graphite sheet into the quartz tube. However, the graphite sheet is relatively thin, and problems such as distortion and cracks are likely to occur during the process of threading the graphite sheet into the bent quartz tube, resulting in a high defect rate.

[0060] In this application, by setting at least the part of the neutral plane F1 facing the bent portion 11 to be parallel to the reference line, the heating element 20 will not be distorted by external forces, so that the heating element 20 can smoothly penetrate into the tube body 10, improving the yield rate, greatly improving the production efficiency, and saving costs.

[0061] For the graphite heating tube 100 according to the embodiment of the present invention, by setting at least the part of the neutral plane F1 facing the bent portion 11 to be parallel to the reference line, the heating element 20 will not be distorted by external forces, so that the heating element 20 can smoothly penetrate into the tube body 10, improving the yield rate, greatly improving the production efficiency, and saving costs.

[0062] In some embodiments, the radius of curvature of the central axis of the bent portion 11 is R1, and the radius of curvature of the portion of the neutral plane F1 opposite to the bent portion 11 is R2, where 0.95 ≤ (R2 / R1) ≤ 1.05. Through years of experience summary by the inventor and induction of a large amount of data, by setting 0.95 ≤ (R2 / R1) ≤ 1.05, the heating element 20 can be further smoothly inserted into the hollow tube body 10, so that the inserted heating element 20 will not be stretched, twisted, bent, etc., improving the yield rate.

[0063] Specifically, R1 is the radius of curvature of the central axis of the bent portion 11. It should be noted that the central axis of the bent portion 11 is different from the bent portion 11. The bent portion 11 is formed into an arc shape. The bent portion 11 is a component with a certain volume. The part of the bent portion 11 close to the center of the circle and the part far from the center of the circle have different radii of curvature. Here, the central axis is a virtual line, and the radius of curvature of the central axis is different from the radii of curvature of other parts on the bent portion 11.

[0064] Among them, in this application, the radius of curvature of the portion of the neutral plane F1 opposite to the bent portion 11 is related to the radius of curvature of the central axis of the bent portion 11, that is, the portion of the neutral plane F1 located within the bent portion 11 is related to the central axis of the bent portion 11, and 0.95 ≤ (R2 / R1) ≤ 1.05, so that the heating element 20 is close to the central axis of the bent portion 11 within the bent portion 11, thereby preventing the heating element 20 from being overly bent, and thus reducing the probability of phenomena such as stretching, twisting, and bending of the heating element 20.

[0065] For example, when R2 / R1 is 1, that is, the central axis of the bent portion 11 is located within the neutral plane F1 of the heating element 20, and the heating element 20 maintains a certain distance from the inner wall of the tube body 10, reducing the probability of phenomena such as stretching, twisting, and bending of the heating element 20; or, when R2 / R1 is 0.95; or, when R2 / R1 is 0.97; or, when R2 / R1 is 1.02; or, when R2 / R1 is 1.05.

[0066] Specifically, in the related art, when encapsulating a graphite heating tube, first, a graphite sheet with connection terminals at both ends is inserted into a quartz tube. The two ends of the quartz tube are heated and melted, pressed by a pressing block, and after cooling, the graphite sheet and the quartz tube are press-sealed into one body. The graphite sheet is sheet-shaped, and the space it occupies is a plane. When inserted into the quartz tube, it can have an arbitrary positional relationship with the swept neutral plane of the quartz tube. Because the graphite sheet is extremely thin, the positioning state formed when the graphite sheet is inserted into the quartz tube and the formed encapsulation process parameters directly determine the qualification rate of manufacturing the graphite heating tube.

[0067] The curved quartz tube, as the outer protective sleeve of the graphite heating tube, is also designed into different shapes according to the spatial position of the product. The curves include circular, U-shaped, S-shaped, etc. As Figure 2 , Figure 3 shown, position the sweep center line of the quartz tube in the XOY plane coordinate system to form the functional relationship y1 = f(x) of the sweep center line. The calculation formula for the radius of curvature is as follows:

[0068]

[0069] where y· is d(y) / d(x), and y·· is d 2 (y) / d(x 2 ). Substitute the functional relationship of the sweep center line of the quartz tube into the radius of curvature calculation formula to obtain the radius of curvature ρa of the sweep center line of the quartz tube. The curved quartz tube is generally formed by connecting several arcs. Assume that the radii of curvature of each section are ρa1, ρa2, ρa3, etc. Specifically, the radius of curvature formula is common knowledge and will not be elaborated here.

[0070] Before introducing the graphite sheet into the quartz tube for press sealing and melting, the positioning state of the graphite sheet after passing through the quartz tube. As Figure 4 , Figure 5 and Figure 6 shown, also position the sweep center line of the graphite sheet after positioning in the XOY plane coordinate system to form the functional relationship y2 = f(x) of the sweep center line of the graphite sheet. Substitute the functional relationship of the sweep center line of the graphite sheet into the radius of curvature calculation formula to obtain the radius of curvature ρb of the sweep center line of the graphite sheet. The radii of curvature ρb1, ρb2, ρb3, etc. of the sweep path of the graphite sheet after positioning in the curved quartz tube. Therefore, calculate the ratio λ = ρb / ρa of the radii of curvature of the graphite sheet and the quartz tube under each section. The ratio of the radii of curvature λ is R2 / R1.

[0071] This application proposes that R2 / R1 is in the range of 0.95 to 1.05, and to ensure that the bending direction of the heating element 20 is consistent with the bending direction of the tube body 10, thereby forming the best process parameters for the positioning position relationship between the heating element 20 and the tube body 10. Under the best parameters, the heating element 20 can smoothly penetrate into various curved tube bodies, especially annular tubes, U-shaped tubes, S-shaped tubes, etc.

[0072] Specifically, positioning the annular tube according to the best position relationship process parameters proposed in this application can smoothly obtain as Figure 7 , Figure 8The annular tube shown. After the heating element 20 is packaged into the tube body 10, the partial enlarged view of the heating element 20 shows that the offset angle between the heating element 20 and the sweeping plane is less than 5°, which makes it difficult for the heating element 20 to contact the inner wall of the tube body 10. At the same time, the teeth of the heating element 20 are evenly distributed, and it is not easy to stretch, twist and bend. After the melt pressing is cooled, cracks are rarely found in the heating element 20.

[0073] Specifically, the U-shaped tube is positioned according to the optimal position relationship process parameters proposed in this application to obtain the following Figure 9 , Figure 10 The U-shaped tube shown in the figure has uniform tooth distribution of the heating element 20, and the offset angle of the heating element 20 is less than 5°. After forming, the heating element 20 is rarely found to have defects such as cracks, excessive stretching, twisting and bending.

[0074] Specifically, the S-shaped tube is positioned according to the process parameters of this application to obtain the following Figure 11 , Figure 12 It can also be seen that the teeth of the heating element 20 are evenly distributed, there is no local large stretching, twisting and bending, and no cracked graphite sheet is seen after molding.

[0075] By setting the heating element 20 to be positioned at various curved tube body positions according to the present application, optimal positioning process parameters are formed. The heating element 20 can be easily inserted into the tube body 10, and it is rare to find a heating element 20 with damage such as stretching, twisting and bending, thereby ensuring the integrity and reliability of the packaged heating element 20. Through the process of the present application, the qualified rate of the packaging manufacturing of the heating element 20 is increased by more than 23%, which greatly improves the production efficiency of the graphite heating tube 100, provides the best process guarantee for the mass production and high qualified rate of the graphite heating tube 100, and saves considerable manufacturing costs.

[0076] like Figure 4 , Figure 5 As shown, in some embodiments, the heating element 20 includes a plurality of heating units 22 arranged in sequence along the length direction, each heating unit 22 is formed as a curved section with an opening facing the first direction, and adjacent heating units 22 are connected by connecting sheets. Through heating by a plurality of heating units 22 arranged in sequence along the length direction, the heating element 20 fully dissipates heat, thereby improving the heating efficiency of the graphite heating tube 100. The first direction is a direction set artificially, and the first direction may be a specific upward direction, a downward direction, a left direction, or a right direction.

[0077] Specifically, the heating unit 22 is formed as a bent section with an opening facing the first direction. The heating element 20 includes a plurality of heating units 22, and the heating units 22 are connected by connecting pieces. That is, the structure of the heating element 20 is: a cycle structure of heating unit 22 + connecting piece + heating unit 22. Of course, it can also be a cycle structure of connecting piece + heating unit 22 + connecting piece.

[0078] In some embodiments, the connecting piece is connected to the middle of the bent section. That is to say, part of the bent section is suspended, which improves the heat generation efficiency.

[0079] In other embodiments, the connecting piece is connected to the end of the bent section. By setting the connecting piece to be connected to the end of the bent section, the probability that the heating element 20 contacts the inner wall of the tube body 10 is reduced.

[0080] Such as Figure 4 、 Figure 5 As shown, in some embodiments, each heating unit 22 includes two parallel heating sidewalls 221. The distance between the two heating sidewalls 221 is the first distance L1, and the gap between adjacent heating units 22 is the second distance L2. The first distance L1 and the second distance L2 are the same. By setting the first distance L1 between the two heating sidewalls 221 to be equal to the second distance L2 between adjacent heating units 22, the heating element 20 heats evenly, the heat around the heating element 20 is the same, and the heating uniformity is improved.

[0081] Among them, each heating unit 22 includes two parallel heating sidewalls 221. Heat is generated by such planes of the two heating sidewalls 221, and the heated plane receives more energy, which improves the heating speed.

[0082] Specifically, the two heating sidewalls 221 are spaced apart by the first distance L1, and the two heating sidewalls 221 heat the surrounding air. The adjacent two heating units 22 are spaced apart by the second distance L2, and the influence ranges of the heating sidewalls 221 of the adjacent two heating units 22 are the same, so that the heating element 20 heats evenly.

[0083] In some embodiments, the first distance L1 is 0.5 mm, and the thickness of the heating element 20 ranges from [0.1 mm, 0.3 mm]. By setting the thickness range of the heating element 20 with the first distance L1 of 0.5 mm to be from 0.1 mm to 0.3 mm, the heating element 20 meets the requirements of both strength and the yield rate of the manufacturing process.

[0084] The inventors of the present application have discovered through a large number of experimental explorations that graphene materials are brittle materials. Generally, the elastic modulus of the graphite sheets of graphene materials is very small. Thus, during the installation process, when being pulled or subjected to the thermal shock load of an instantaneous 1000-degree high temperature during power-on heating after installation, it is very easy for the graphite sheets to break, resulting in the failure of the heating tube. According to the calculation formula of the elastic modulus of elastic materials, the strength of the material itself can be improved by increasing the material thickness. However, there are manufacturing process problems when increasing the material thickness. The related process of manufacturing graphite sheet materials is to press the graphene material of porous medium material into a sheet material through a physical pressing method, and then use a die cutter to cut into the shape as shown in Figure 5 shown. In this process, when the thickness of the graphite sheet increases to a certain extent, the shear stress of the cut surface will correspondingly decrease during the die cutting process. Therefore, it is very easy for the graphite materials to adhere to each other during the cutting process, resulting in burrs on the finished product after cutting, leading to the production of defective products. In terms of this problem, the thickness of the graphene material has always been a contradictory point.

[0085] In terms of the manufacturing process, to quickly cut the graphite sheet and reduce burrs, the overall shear stress range should be greater than 4 MPa. To ensure no damage during actual working conditions, the tensile strength of the graphite sheet should be greater than 3.5 MPa. Through a large number of simulation and experimental studies, the inventors of the present application have found that under the cutting pattern with a 0.5 mm spacing, when the thickness is in the range of [0.1 mm, 0.3 mm], the requirements of both strength and manufacturing process can be satisfied simultaneously.

[0086] Specifically as follows: The thickness of the graphite sheet with a 0.5 mm spacing cutting pattern is 0.1 mm, the tensile strength is 3.5 MPa, and the shear stress is 15 MPa; the thickness of the graphite sheet with a 0.5 mm spacing cutting pattern is 0.2 mm, the tensile strength is 7.3 MPa, and the shear stress is 9.8 MPa; the thickness of the graphite sheet with a 0.5 mm spacing cutting pattern is 0.3 mm, the tensile strength is 10.7 MPa, and the shear stress is 4.3 MPa.

[0087] For example, the thickness of the heating element 20 is 0.1 mm; or, the thickness of the heating element 20 is 0.15 mm; or, the thickness of the heating element 20 is 0.2 mm; or, the thickness of the heating element 20 is 0.25 mm; or, the thickness of the heating element 20 is 0.3 mm.

[0088] Specifically, the thickness of the heating element 20 is 0.2 mm. By setting the thickness to 0.2 mm, a margin of nearly 1 time is reserved for both the shear stress and the tensile strength at this thickness, thus improving the overall reliability.

[0089] In some embodiments, the tube body 10 is a circular tube. By setting the tube body 10 as a circular tube, it is convenient to encapsulate the heating element 20 into the tube body 10, reducing the probability of damage during the press-sealing process and further improving the yield rate.

[0090] Specifically, the cross-section of the circular tube is circular. When the heating element 20 penetrates into the circular tube, the distances between the heating element 20 and each part of the inner wall of the circular tube are similar, so it is easier to control the heating element 20.

[0091] In other embodiments, the tube body 10 is a rhombic tube. Specifically, the cross-section of the rhombic tube is rhombic.

[0092] Such as Figure 4 、 Figure 13 As shown, in some embodiments, both ends of the heating element 20 in the length direction are connected with connection terminals 23. Each connection terminal 23 is press-sealed and fixed with the tube body 10, and a part of the connection terminal 23 extends out of the tube body 10. By setting the connection terminal 23 to be press-sealed and fixed with the tube body 10, the heating element 20 is stably fixed in the tube body 10.

[0093] Specifically, the press-sealing process is as follows: First, gently insert the heating element into the tube body to ensure appropriate extension amounts at both ends of the connection terminal. Then, by methods such as flame heating, heat the two ends of the tube body to the molten state, and then quickly close the pressing blocks on both sides of the tube body to squeeze the molten tube body. When the tube body cools down, the connection terminal and the tube body are press-sealed together, finally forming a vacuum closed space, and completing the process of encapsulating the heating element into the tube body.

[0094] In some embodiments, the connection terminal 23 includes a main body part 231 and a packaging part 232. The main body part 231 is connected to the heating element 20, the packaging part 232 is connected to the main body part 231 and is press-sealed and fixed with the tube body 10, and the main body part 231 and the packaging part 232 have an included angle. By setting an included angle between the main body part 231 and the packaging part 232, the probability of problems such as air leakage of the graphite heating tube 100 and cracks occurring on the heating element 20 and the connection terminal 23 during the process of press-sealing the connection terminal 23 with the tube body 10 is reduced.

[0095] In the related art, during the process of encapsulating a graphite sheet into a quartz tube, the graphite sheet is relatively randomly inserted into the quartz tube. When the quartz tube cools and solidifies, the graphite sheet is stressed, and the graphite sheet may be deformed and distorted. The graphite sheet may be squeezed against the inner wall of the quartz tube. These various situations cause cracks in the graphite sheet, resulting in a low qualification rate. In this application, by setting an included angle between the main body part 231 and the packaging part 232 in advance, the deformation of the heating element 20 during the cooling and solidification process of the tube body 10 is improved, the probability of crack generation is reduced, and the qualification rate of encapsulation manufacturing is increased.

[0096] In some embodiments, the included angle θ between the main body portion 231 and the encapsulation portion 232 is 180°. Specifically, the tube body 10 is a straight tube, and the state of the straight tube is as Figure 13 , Figure 16 shown, the included angle θ is 180°; when encapsulating in parallel, the parallel relationship between the graphite sheet and the pressing and sealing plane, and when penetrating, the graphite sheet will not be stretched and distorted; and when melt-pressing and sealing, the terminals at both ends are not likely to form an uneven forming state with the pressing and sealing plane, reducing the generation of cracks in the terminals and air leakage at the pressed and sealed tube head.

[0097] In some embodiments, the main body portion 231 and the encapsulation portion 232 are vertically arranged. By arranging the main body portion 231 and the encapsulation portion 232 vertically, the heating element 20 can be easily penetrated into the tube body 10, and it is not easy to cause damage such as stretching, twisting, and bending to the sheet-shaped heating element 20, ensuring the integrity of the encapsulated heating element 20; at the same time, when melt-pressing and sealing, the parallel state between the connection terminal 23 and the tube head of the tube body 10 can be maintained, greatly reducing the cracks in the connection terminal 23 and air leakage at the tube head.

[0098] For example, the tube body 10 is a straight tube, and the state of the heating element 20 of the straight tube is as Figure 17 , Figure 18 shown, the included angle θ is 90°. Before gently penetrating the graphite sheet, the terminals at both ends are twisted by 90°, so that the neutral plane of the penetrated graphite sheet is perpendicular to the pressing and sealing neutral plane of the quartz tube head to be formed, and at the same time the terminals and the tube head pressing surface are parallel. The vertical encapsulation of the straight tube is not likely to cause cracks in the terminals and air leakage at the tube head, and at the same time, the graphite sheet will not be stretched and distorted.

[0099] Alternatively, the tube body 10 is any one of a ring-shaped tube, a U-shaped tube, and an S-shaped tube, and the included angle θ is 90°, so that the neutral plane F1 and the pressing and sealing neutral plane of the tube head of the tube body 10 are in a vertical state. The pressing and sealing encapsulation of the ring-shaped tube is as Figure 19 , Figure 20 shown. When the heating element 20 penetrates into the ring-shaped tube, in this vertical state, the included angle θ is 90°, so that the heating element 20 can easily penetrate along the neutral plane of the ring-shaped tube, and the heating element 20 is not easy to be stretched and distorted; when the connection terminal 23 is melt-pressed and sealed, it can also better maintain parallelism with the pressing and sealing of the tube head of the tube body 10, reducing the generation of cracks in the connection terminal 23 and air leakage at the pressed and sealed tube head. The pressing and sealing encapsulation of the U-shaped tube is as Figure 21 , Figure 22 shown, and similar to the ring-shaped tube, it can also ensure that the heating element 20 easily passes through the semi-circle, ensuring the manufacturing qualification rate during penetration and encapsulation. The pressing and sealing encapsulation of the S-shaped tube is as Figure 23 , Figure 24 shown, and also similar to the ring-shaped tube and the U-shaped tube. When the heating element 20 passes through the bent portion 11 on the tube body 10, it is not easy to be stretched and distorted, and at the same time, the connection terminal 23 is rarely air-leaked and cracked during melt-pressing and sealing.

[0100] Specifically, the probability of various problems occurring in the circular tube of C-1 before process improvement is as follows: graphite film breakage 1.13%, graphite sheet scratch 3.62%, graphite sheet twist 2.83%, graphite sheet crease 5.51%, molybdenum sheet crack 6.82%, molybdenum sheet wrinkle 6.78%, sealing bubble 7.58%, sealing air leakage 5.31%, total 39.58%; after process improvement, it is as follows: graphite film breakage 0.54%, graphite sheet scratch 1.45%, graphite sheet twist 2.13%, graphite sheet crease 2.55%, molybdenum sheet crack 1.97%, molybdenum sheet wrinkle 2.96%, sealing bubble 2.65%, sealing air leakage 1.62%, total 15.87%, and the qualified rate improvement before and after improvement is 23.7%.

[0101] Specifically, the probability of various problems occurring in the circular tube of C-2 before process improvement is as follows: graphite film breakage 1.15%, graphite sheet scratch 3.11%, graphite sheet twist 2.65%, graphite sheet crease 5.16%, molybdenum sheet crack 6.95%, molybdenum sheet wrinkle 6.12%, sealing bubble 7.74%, sealing air leakage 5.46%, total 38.34%; after process improvement, it is as follows: graphite film breakage 0.52%, graphite sheet scratch 1.41%, graphite sheet twist 2.15%, graphite sheet crease 2.52%, molybdenum sheet crack 1.82%, molybdenum sheet wrinkle 2.84%, sealing bubble 2.53%, sealing air leakage 1.56%, total 15.35%, and the qualified rate improvement before and after improvement is 23.0%.

[0102] Specifically, the probability of various problems occurring in the U-shaped tube of U-1 before process improvement is as follows: graphite film breakage 1.12%, graphite sheet scratch 3.82%, graphite sheet twist 2.74%, graphite sheet crease 5.37%, molybdenum sheet crack 6.72%, molybdenum sheet wrinkle 6.25%, sealing bubble 7.32%, sealing air leakage 4.9%, total 38.24%; after process improvement, it is as follows: graphite film breakage 0.52%, graphite sheet scratch 1.43%, graphite sheet twist 2.16%, graphite sheet crease 2.47%, molybdenum sheet crack 1.94%, molybdenum sheet wrinkle 2.94%, sealing bubble 2.42%, sealing air leakage 1.51%, total 15.39%, and the qualified rate improvement before and after improvement is 22.9%.

[0103] Specifically, the probability of various problems occurring in the S-shaped tube of S-1 before process improvement is as follows: graphite sheet broken film 1.10%, graphite sheet scratched 3.78%, graphite sheet sprained 2.81%, graphite sheet creased 5.11%, molybdenum sheet cracked 6.42%, molybdenum sheet wrinkled 6.85%, press seal bubble 7.12%, press seal air leakage 4.77%, total 37.96%; after process improvement, it is as follows: graphite sheet broken film 0.51%, graphite sheet scratched 1.46%, graphite sheet sprained 2.18%, graphite sheet creased 2.49%, molybdenum sheet cracked 1.81%, molybdenum sheet wrinkled 2.87%, press seal bubble 2.42%, press seal air leakage 1.55%, total 15.29%, and the qualified rate improvement rate before and after improvement is 22.7%.

[0104] Specifically, the probability of various problems occurring in the S-shaped tube of S-1 before process improvement is as follows: graphite sheet broken film 1.11%, graphite sheet scratched 3.73%, graphite sheet sprained 2.92%, graphite sheet creased 5.05%, molybdenum sheet cracked 6.38%, molybdenum sheet wrinkled 6.81%, press seal bubble 7.04%, press seal air leakage 4.63%, total 37.67%; after process improvement, it is as follows: graphite sheet broken film 0.58%, graphite sheet scratched 1.41%, graphite sheet sprained 2.20%, graphite sheet creased 2.41%, molybdenum sheet cracked 1.86%, molybdenum sheet wrinkled 2.81%, press seal bubble 2.34%, press seal air leakage 1.48%, total 15.09%, and the qualified rate improvement rate before and after improvement is 22.6%.

[0105] In summary, the proportion of defective graphite heating tubes has decreased significantly, and the overall qualified rate has increased by about 23%.

[0106] Next, in combination with Figures 1 to 24 , a specific embodiment of the graphite heating tube 100 of the present invention will be described.

[0107] A graphite heating tube 100 includes: a tube body 10 and a heating element 20.

[0108] The tube body 10 is a hollow quartz tube. The shape of the tube body 10 is a U-shaped tube. The tube body 10 is a circular tube with a circular cross-section. The tube body 10 has a bending portion 11, and the bending portion 11 is formed into an arc shape. A reference line is defined to pass through the center of the bending portion 11 and is perpendicular to the radius direction of the bending portion 11.

[0109] The heating element 20 is a sheet-shaped graphene material element. The heating element 20 is disposed through the tube body 10. The heating element 20 includes a plurality of heating units 22 arranged sequentially along the length direction. Each heating unit 22 is formed as a bent section with an opening facing the first direction. Adjacent heating units 22 are connected by connecting pieces, and the connecting pieces are connected to the ends of the bent sections. Each heating unit 22 includes two parallel heating side walls 221. The distance between the two heating side walls 221 is a first distance L1, and the gap between adjacent heating units 22 is a second distance L2. The first distance L1 and the second distance L2 are the same. The first distance L1 is 0.5 mm, and the thickness of the heating element 20 is 0.2 mm.

[0110] Connection terminals 23 are connected to both ends of the heating element 20 in the length direction. Each connection terminal 23 is press-sealed and fixed to the tube body 10, and a part of the connection terminal 23 extends out of the tube body 10. The connection terminal 23 includes a main body portion 231 and a packaging portion 232. The main body portion 231 is connected to the heating element 20, the packaging portion 232 is connected to the main body portion 231 and is press-sealed and fixed to the tube body 10, and the main body portion 231 and the packaging portion 232 are perpendicularly arranged.

[0111] Wherein, in the thickness direction of the heating element 20, the heating element 20 has a neutral plane F1 at the center. The neutral plane F1 extends along the length direction of the tube body 10, and at least the part of the neutral plane F1 facing the bending portion 11 is parallel to the reference line. The radius of curvature of the central axis of the bending portion 11 is R1, and the radius of curvature of the part of the neutral plane F1 facing the bending portion 11 is R2. R2 / R1 is 1.

[0112] The cooking device according to an embodiment of the present invention includes the above-mentioned graphite heating tube 100.

[0113] The cooking device according to an embodiment of the present invention sets at least the part of the neutral plane F1 facing the bending portion 11 to be parallel to the reference line, so that the heating element 20 will not be distorted by external forces, enabling the heating element 20 to smoothly penetrate into the tube body 10, improving the yield rate, greatly improving the production efficiency, and saving costs.

[0114] In some embodiments, the cooking device includes: a box body, a drawer member, and the graphite heating tube 100.

[0115] A drawer opening is provided on the front side of the box body.

[0116] The drawer member is used for holding food, and the drawer member is slidable relative to the box body through the drawer opening.

[0117] The graphite heating tube 100 is disposed in the box body to heat the interior of the box body.

[0118] Among them, the drawer is used to hold food. Compared with the solution in the related art where the food carrying space is fixed inside the cooking appliance, it is convenient to place and take out food in this application.

[0119] For example, the cooking device is an oven; or, the cooking device is an air fryer; or, the cooking device is a microwave oven.

[0120] Other components and operations of the graphite heating tube 100 according to the embodiments of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0121] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0122] In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features, which are used to distinguish and describe features, without order or importance.

[0123] In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0124] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0125] In the description of this specification, the description referring to terms such as "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0126] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A graphite heating tube, characterized in that, Comprising: A hollow tube body, the tube body having at least one bent portion, the bent portion being formed in an arc shape, a reference line being defined as passing through the center of the bent portion and being perpendicular to the radial direction of the bent portion; A heating element, the heating element being formed as a sheet-like graphene material element, the heating element being disposed through the tube body, in the thickness direction of the heating element, the heating element having a neutral plane at the center, the neutral plane extending along the length direction of the tube body, at least a part of the neutral plane facing the bent portion being arranged parallel to the reference line.

2. The graphite heating tube according to claim 1, characterized in that, The radius of curvature of the central axis of the bent portion is R1, and the radius of curvature of the part of the neutral plane facing the bent portion is R2, 0.95 ≦ (R2 / R1) ≦ 1.

05.

3. The graphite heating tube according to claim 1, wherein The heating element includes a plurality of heating units arranged in sequence along the length direction, each heating unit being formed as a bent section with an opening facing a first direction, and adjacent heating units being connected by connecting pieces.

4. The graphite heating tube according to claim 3, characterized in that, The connecting piece is connected to the end of the bent section.

5. The graphite heating tube according to claim 3, characterized in that, Each heating unit includes two parallel heating side walls, the distance between the two heating side walls being a first distance, and the gap between adjacent heating units being a second distance, the first distance and the second distance being the same.

6. The graphite heating tube according to claim 5, wherein The first distance is 0.5 mm, and the thickness of the heating element ranges from [0.1 mm, 0.3 mm].

7. The graphite heating tube according to claim 6, wherein The thickness of the heating element is 0.2 mm.

8. The graphite heating tube according to claim 1, wherein, The tube body is a circular tube.

9. The graphite heating tube according to any one of claims 1-8, characterized in that, Both ends of the heating element in the length direction are connected with connection terminals, each connection terminal being press-sealed and fixed to the tube body and a part of the connection terminal protruding from the tube body.

10. The graphite heating tube according to claim 9, characterized in that, The connection terminal includes a main body portion and a packaging portion, the main body portion being connected to the heating element, the packaging portion being connected to the main body portion and press-sealed and fixed to the tube body, and the main body portion and the packaging portion having an included angle.

11. The graphite heating tube according to claim 10, characterized in that, The main body portion and the packaging portion are perpendicularly arranged.

12. A cooking device, characterized in that, Including the graphite heating tube according to any one of claims 1 to 11.

13. The cooking device according to claim 12, characterized in that, The cooking device includes: A box body, a draw opening being provided on the front side of the box body; A draw member for holding food, the draw member being drawable relative to the box body through the draw opening; A graphite heating tube, the graphite heating tube being disposed in the box body to heat the interior of the box body.

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