Carbonaceous heating tube and cooking equipment

Abstract

The utility model discloses a carbonaceous heating tube and cooking equipment, and the carbonaceous 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 carbonaceous 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 utility model, 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 element cannot be twisted by external force, the heating element can smoothly penetrate into the pipe body, the yield is improved, the production efficiency is greatly improved, and the cost is saved.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application "Graphite heating tube and cooking equipment" with application number: 202323537885.2 and application date of December 22, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The utility model relates to the technical field of cooking devices, in particular to a carbon heating tube and cooking equipment. Background Art

[0004] In the related art, graphite heating tubes are made by vacuum-sealing graphite sheets into quartz tubes. However, the graphite sheets are relatively thin, and are prone to distortion and cracking when inserted into the curved quartz tube, resulting in a high defect rate. Utility Model Content

[0005] The present invention aims to solve at least one of the technical problems in the prior art. To this end, the present invention proposes a carbon heating tube to improve the yield rate.

[0006] According to an embodiment of the present invention, the carbon heating tube includes: a hollow tube body, the tube body having at least one bending portion, the bending portion being formed in an arc shape, and a reference line being defined passing through the center of the bending portion and being arranged perpendicular to the radius direction of the bending portion; a heating element, the heating element being formed as a sheet-like carbon material piece, the heating element being passed through the tube body, and having a neutral plane located in the center in the thickness direction of the heating element, the neutral plane extending along the length direction of the tube body, and at least the portion of the neutral plane facing the bending portion being arranged parallel to the reference line.

[0007] According to the carbon heating tube of the embodiment of the present invention, by setting at least the portion of the neutral surface opposite to the bent portion parallel to the reference line, the heating element will not be distorted by external forces, allowing the heating element to smoothly penetrate into the tube body, thereby improving the yield rate, greatly improving production efficiency, and saving costs.

[0008] In some embodiments, the curvature radius of the central axis of the bending portion is R1, the curvature radius of a portion of the neutral plane directly opposite to the bending portion is R2, and 0.95≤(R2 / R1)≤1.05.

[0009] In some embodiments, the heating element includes a plurality of heating units sequentially arranged along the length direction, each of the heating units is formed as a curved section with an opening facing the first direction, and adjacent heating units are connected by a connecting piece.

[0010] In some embodiments, the connecting piece is connected to the end of the curved section.

[0011] In some embodiments, each of the heating units includes two parallel heating side walls, the spacing between the two heating side walls is a first spacing, the gap between adjacent heating units is a second spacing, and the first spacing and the second spacing are the same.

[0012] In some embodiments, the first spacing is 0.5 mm, and the thickness of the heating element is in the range of [0.1 mm, 0.3 mm].

[0013] In some embodiments, the thickness of the heating element is 0.2 mm.

[0014] In some embodiments, the tube body is a circular tube.

[0015] In some embodiments, the carbonaceous material piece includes an artificial graphite piece, a natural graphite piece, and a graphene material piece.

[0016] In some embodiments, both ends of the heating element in the longitudinal direction are connected to connecting terminals, each of the connecting terminals is press-sealed and fixed to the tube body, and a portion of the connecting terminal extends out of the tube body.

[0017] In some embodiments, the connecting terminal includes a main body and a packaging portion, the main body is connected to the heating element, the packaging portion is connected to the main body and is sealed and fixed to the tube body, and the main body and the packaging portion have an angle.

[0018] In some embodiments, the main body portion and the packaging portion are vertically arranged.

[0019] The cooking device according to the embodiment of the present invention includes the above-mentioned carbon heating tube.

[0020] According to the cooking device of the embodiment of the present invention, at least the portion of the neutral surface opposite to the bending portion is arranged parallel to the reference line, so that the heating element will not be distorted by external force, and the heating element can smoothly penetrate into the tube body, thereby improving the yield rate, greatly improving production efficiency, and saving costs.

[0021] In some embodiments, the cooking device includes: a box body, a pull-out opening is provided on the front side of the box body; a pull-out piece for holding food, the pull-out piece can be pulled out relative to the box body through the pull-out opening; and a carbon heating tube, the carbon heating tube is provided in the box body to heat the inside of the box body.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of a carbon heating tube in the first embodiment of the present invention, wherein the carbon heating tube is in a state ready for compression sealing;

[0025] Figure 2 This is a schematic diagram of the tube body after compression sealing in the first embodiment of the present invention, wherein the tube body is partially cut away;

[0026] Figure 3 Schematic diagram of the curvature of the central axis of each part of the tube body in the embodiment of the present utility model;

[0027] Figure 4 This is a schematic structural diagram of a heating element in an embodiment of the present utility model;

[0028] Figure 5 for Figure 4 A partial enlarged view of point I in the middle;

[0029] Figure 6 Schematic diagram of the sweep path formed after the heating element is positioned in the tube body in the embodiment of the present invention;

[0030] Figure 7 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the utility model Figure 1 ;

[0031] Figure 8 for Figure 7 A partial enlarged view of position II in the middle;

[0032] Figure 9 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the utility model Figure 1 ;

[0033] Figure 10 for Figure 9 A partial enlarged view of point III in the middle;

[0034] Figure 11 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the utility model Figure 1 ;

[0035] Figure 12 for Figure 11 A partial enlarged view of position IV in the middle;

[0036] Figure 13 This is an exploded view of a carbon heating tube in an embodiment of the present utility model;

[0037] Figure 14This is a schematic diagram of a carbon heating tube in a second embodiment of the present invention, wherein the carbon heating tube is in a state ready for compression sealing;

[0038] Figure 15 This is a schematic diagram of the carbon heating tube after compression sealing in the second embodiment of the present invention, wherein the tube body is partially cut away;

[0039] Figure 16 Schematic diagram of the angle θ in the embodiment of the present utility model;

[0040] Figure 17 This is a schematic diagram of the cooperation between the heating element and the straight tube in the embodiment of the present utility model;

[0041] Figure 18 for Figure 17 A partial enlarged view of the middle V;

[0042] Figure 19 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the utility model Figure 2 ;

[0043] Figure 20 Schematic diagram of the cooperation between the heating element and the annular tube in the embodiment of the utility model Figure 3 ;

[0044] Figure 21 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the utility model Figure 2 ;

[0045] Figure 22 Schematic diagram of the cooperation between the heating element and the U-shaped tube in the embodiment of the utility model Figure 3 ;

[0046] Figure 23 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the utility model Figure 2 ;

[0047] Figure 24 Schematic diagram of the cooperation between the heating element and the S-shaped tube in the embodiment of the utility model Figure 3 .

[0048] Reference numerals:

[0049] 100. Carbon heating tube;

[0050] 10. Tube body; 11. Bending portion;

[0051] 20. Heating element; 22. Heating unit; 221. Heating side wall; 23. Connecting terminal; 231. Main body; 232. Packaging part;

[0052] F1, neutral plane; F2, pressing block; L1, first distance; L2, second distance. DETAILED DESCRIPTION

[0053] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0054] The carbon heating tube 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0055] like Figure 1 As shown, according to an embodiment of the present invention, a carbon heating tube 100 includes a tube body 10 and a heating element 20 .

[0056] The tube body 10 is hollow and has at least one bending portion 11 . The bending portion 11 is formed in an arc shape. A reference line is defined passing through the center of the bending portion 11 and is perpendicular to the radius of the bending portion 11 .

[0057] The reference line is a virtual line. This application defines the reference line as a virtual line that passes through the center of the bending portion 11 and is perpendicular to the radius direction of the bending portion 11 of the tube body 10 .

[0058] Specifically, the tube body 10 has at least one bending portion 11, and the bending portion 11 is formed in an arc shape. For example, the overall appearance of the tube body 10 is U-shaped, and the middle part of the U-shaped tube is the arc-shaped bending portion 11; or, the overall appearance of the tube body 10 is S-shaped, and multiple parts of the S-shaped tube are arc-shaped; or, the overall appearance of the tube body 10 is ring-shaped, and each part of the ring-shaped tube is arc-shaped.

[0059] The heating element 20 is formed as a sheet of carbonaceous material. The heating element 20 is inserted into the tube body 10. In the thickness direction of the heating element 20, the heating element 20 has a neutral plane F1 located in the center. The neutral plane F1 extends along the length direction of the tube body 10. At least the part of the neutral plane F1 that is opposite to the bending portion 11 is arranged parallel to the reference line.

[0060] The carbonaceous material itself has excellent heat conduction and heat dissipation capabilities. The carbon heating tube 100 of the present application utilizes the capabilities of the carbonaceous material, so that the carbon heating tube 100 has the advantages of fast heating speed and strong radiation.

[0061] Specifically, the carbon heating tube 100 can be a graphite heating tube. Carbon materials include artificial graphite, natural graphite, and graphene materials, which increase heating speed and radiation. Alternatively, the carbon heating tube 100 can be a carbon fiber heating tube. The carbon material is carbon fiber filaments, which have excellent electrical conductivity and high temperature resistance.

[0062] The neutral plane F1 is a virtual plane. This application defines the neutral plane F1 as a virtual plane located at the center of the heating element 20 in the thickness direction and extending along the length direction of the tube body 10 .

[0063] In the related art, graphite heating tubes are made by vacuum-sealing graphite sheets into quartz tubes. However, the graphite sheets are relatively thin, and are prone to distortion and cracking when inserted into the curved quartz tube, resulting in a high defect rate.

[0064] The present application sets at least the portion of the neutral plane F1 that is opposite to the bending portion 11 to be parallel to the reference line, so that the heating element 20 will not be distorted by external forces, and the heating element 20 can smoothly penetrate into the tube body 10, thereby improving the yield rate, greatly improving production efficiency, and saving costs.

[0065] According to the carbon heating tube 100 of the embodiment of the present invention, at least the portion of the neutral plane F1 that is opposite to the bent portion 11 is arranged parallel to the reference line, so that the heating element 20 will not be distorted by external forces, allowing the heating element 20 to smoothly penetrate into the tube body 10, thereby improving the yield rate, greatly improving production efficiency, and saving costs.

[0066] In some embodiments, the radius of curvature of the central axis of the bend 11 is R1, the radius of curvature of the portion of the neutral plane F1 directly opposite the bend 11 is R2, and 0.95≤(R2 / R1)≤1.05. Based on years of experience and extensive data analysis, the inventors have determined that setting 0.95≤(R2 / R1)≤1.05 further allows the heater 20 to smoothly penetrate the hollow tube 10 without stretching, twisting, or bending, thereby improving product yield.

[0067] Specifically, R1 is the curvature radius of the central axis of the bending portion 11. It should be noted that the central axis of the bending portion 11 is different from the bending portion 11. The bending portion 11 is formed in an arc shape. The bending portion 11 is a component with a certain volume. The part of the bending portion 11 close to the center of the circle and the part away from the center of the circle have different curvature radii. Here, the central axis is a virtual line, and the curvature radius of the central axis is different from the curvature radius of other parts on the bending portion 11.

[0068] Among them, the curvature radius of the part of the neutral plane F1 set opposite to the bending part 11 in this application has a certain correlation with the curvature radius of the central axis of the bending part 11, that is, the part of the neutral plane F1 located in the bending part 11 has a certain correlation with the central axis of the bending part 11, 0.95≤(R2 / R1)≤1.05, so that the heating element 20 is close to the central axis of the bending part 11 in the bending part 11, so that the heating element 20 will not be excessively bent, thereby reducing the probability of the heating element 20 being stretched, twisted and bent.

[0069] For example, R2 / R1 is 1, that is, the central axis of the bending 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, thereby reducing the probability of the heating element 20 being stretched, twisted, bent, and the like; or, R2 / R1 is 0.95; or, R2 / R1 is 0.97; or, R2 / R1 is 1.02; or, R2 / R1 is 1.05.

[0070] Specifically, in related art, when packaging carbon heating tubes, a graphite sheet with connecting terminals at both ends is first inserted into a quartz tube. The ends of the quartz tube are heated and melted, then pressed into blocks. After cooling, the graphite sheet and the quartz tube are compressed and sealed together. The graphite sheet is sheet-shaped and occupies a flat surface. When inserted into the quartz tube, it can be positioned in any position relative to the swept neutral plane of the quartz tube. Because the graphite sheet is extremely thin, the positioning state formed by the graphite sheet when inserted into the quartz tube, and the resulting packaging process parameters, directly determine the qualified rate of carbon heating tube manufacturing.

[0071] The curved quartz tube is the outer protective cover of the carbon heating tube and is also designed into different shapes according to the spatial position of the product. The curved shapes include round, U-shaped and S-shaped. Figure 2 、 Figure 3 As shown, the sweep center line of the quartz tube is positioned in the XOY plane coordinate system to form a functional relationship of the sweep center line y1 = f(x). The calculation formula of the curvature radius is as follows:

[0072]

[0073] Where y· is d(y) / d(x), y·· is d 2 (y) / d(x 2 ), the function relationship of the swept center line of the quartz tube is substituted into the curvature radius calculation formula to obtain the curvature radius ρa of the swept center line of the quartz tube. The curved quartz tube is generally composed of several arc segments. It is assumed that the curvature radius of each segment is ρa1, ρa2 and ρa3, etc. Specifically, the curvature radius formula is common knowledge and will not be repeated here.

[0074] The graphite sheet is introduced into the quartz tube for pressure sealing and melting, and the positioning state of the graphite sheet after it penetrates the quartz tube. Figure 4 、 Figure 5 and Figure 6As shown, the graphite sheet's swept centerline after positioning is also located in the XOY plane coordinate system, forming the functional relationship y2 = f(x) for the graphite sheet's swept centerline. Substituting this functional relationship into the curvature radius calculation formula yields the curvature radius ρb of the graphite sheet's swept centerline, and the curvature radii ρb1, ρb2, and ρb3 of the graphite sheet's swept path after positioning in the curved quartz tube. Therefore, the curvature radius ratio λ = ρb / ρa for each segment of the graphite sheet and quartz tube is calculated. The curvature radius ratio λ is R2 / R1.

[0075] The present application proposes that R2 / R1 is within the range of 0.95 to 1.05, and that the bending direction of the heating element 20 is consistent with the bending direction of the tube body 10, thereby forming the optimal process parameters for the positioning relationship between the heating element 20 and the tube body 10. Under the optimal parameters, the heating element 20 can smoothly penetrate into various curved tubes, especially annular tubes, U-shaped tubes and S-shaped tubes.

[0076] Specifically, the positioning of the annular tube can be carried out according to the optimal position relationship process parameters proposed in this application, and the following can be obtained smoothly: Figure 7 、 Figure 8 The annular tube shown. A partial enlarged view of the heater 20 after encapsulation into the tube body 10 shows that the offset angle between the heater 20 and the sweep plane is less than 5°, making it less likely for the heater 20 to come into contact with the inner wall of the tube body 10. Furthermore, the teeth of the heater 20 are evenly distributed, making it less susceptible to stretching, twisting, and bending. After cooling from the melt press, cracks in the heater 20 are rarely observed.

[0077] 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 on the heating element 20, and the offset angle of the heating element 20 is less than 5°. After forming, the heating element 20 rarely has defects such as cracks, excessive stretching, twisting and bending.

[0078] 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, without any local large stretching, twisting or bending, and no cracked graphite sheet is seen after forming.

[0079] By positioning the heating element 20 to various curved tube body positions according to the present application, optimal positioning process parameters are formed. This allows the heating element 20 to easily penetrate the tube body 10, and rarely finds heating elements 20 damaged by stretching, twisting, bending, etc., thus 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 has been increased by more than 23%, which has greatly improved the production efficiency of the carbon heating tube 100, provided the best process guarantee for the mass production and high qualified rate of the carbon heating tube 100, and saved considerable manufacturing costs.

[0080] like Figure 4 、 Figure 5 As shown, in some embodiments, the heating element 20 includes multiple heating units 22 arranged sequentially along the length. Each heating unit 22 is formed as a curved segment with an opening facing a first direction. Adjacent heating units 22 are connected by connecting pieces. Heating through multiple heating units 22 arranged sequentially along the length allows the heating element 20 to effectively dissipate heat, thereby improving the heating efficiency of the carbon heating tube 100. The first direction is a manually set direction and can be specifically upward, downward, leftward, or rightward.

[0081] Specifically, the heating unit 22 is formed as a curved section with an opening toward the first direction. The heating element 20 includes a plurality of heating units 22, and the heating units 22 are connected by connecting plates, that is, the structure of the heating element 20 is: a circulation structure of heating unit 22 + connecting plate + heating unit 22. Of course, it can also be a circulation structure of connecting plate + heating unit 22 + connecting plate.

[0082] In some embodiments, the connecting piece is connected to the middle portion of the curved section, that is, the curved section is partially suspended, thereby improving the heating efficiency.

[0083] In other embodiments, the connecting piece is connected to the end of the curved section. By providing the connecting piece to be connected to the end of the curved section, the probability of the heating element 20 contacting the inner wall of the tube body 10 is reduced.

[0084] like Figure 4 、 Figure 5 As shown, in some embodiments, each heating unit 22 includes two parallel heating side walls 221. The spacing between the two heating side walls 221 is a first spacing L1, and the spacing between adjacent heating units 22 is a second spacing L2. The first spacing L1 and the second spacing L2 are equal. By setting the first spacing L1 between the two heating side walls 221 to be equal to the second spacing L2 between adjacent heating units 22, the heating element 20 is heated uniformly, and the heat around the heating element 20 is uniform, thereby improving heating uniformity.

[0085] Each heating unit 22 includes two parallel heating side walls 221 . Heat is generated by the two heating side walls 221 , and the heated surface receives more energy, thereby increasing the heating speed.

[0086] Specifically, the two heating side walls 221 are spaced apart by a first distance L1, and the two heating side walls 221 heat the surrounding air. The two adjacent heating units 22 are spaced apart by a second distance L2, and the heating side walls 221 of the two adjacent heating units 22 have the same influence range, so that the heating element 20 is heated evenly.

[0087] In some embodiments, the first spacing L1 is 0.5 mm, and the thickness of the heating element 20 ranges from 0.1 mm to 0.3 mm. By setting the thickness of the heating element 20 with a first spacing L1 of 0.5 mm to a range of 0.1 mm to 0.3 mm, the heating element 20 meets both strength and manufacturing process yield requirements.

[0088] After a lot of experimental research, the inventor of the present application found that: carbonaceous materials are brittle materials. Usually, the elastic modulus of graphite sheets of carbonaceous materials is very small. Therefore, when they are pulled during the installation process or subjected to a thermal shock load of 1000 degrees when powered on and heated after installation, it is easy to cause the graphite sheets to break, resulting in 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 thickness of the material. However, increasing the thickness of the material also has the problem of manufacturing process. The related process for manufacturing graphite sheets is to press the carbonaceous material of porous medium material into sheet material by physical pressing, and then use a knife die to shear it. Figure 5 As shown in the shape, in this process, when the thickness of the graphite sheet increases to a certain extent, the shear stress of the cut surface will decrease accordingly during the shearing process of the die. Therefore, it is easy for the graphite materials to stick together during the cutting process, resulting in burrs on the finished product after cutting, resulting in the production of defective products. In this regard, the thickness of the carbon material has always been a contradiction.

[0089] In terms of manufacturing process, in order to quickly cut the graphite sheet and reduce burrs, the overall shear stress range should be greater than 4MPa. In order to ensure that it is not damaged during actual working conditions, the tensile strength of the graphite sheet should be greater than 3.5MPa. After a lot of simulation and experimental research, the inventor of the present application found that when the cutting spacing is 0.5mm, when the thickness is in the range of [0.1mm, 0.3mm], the strength and manufacturing process requirements can be met at the same time.

[0090] Specifically: the thickness of the 0.5mm spacing cut graphite sheet is 0.1mm, the tensile strength is 3.5MPa, and the shear stress is 15MPa; the thickness of the 0.5mm spacing cut graphite sheet is 0.2mm, the tensile strength is 7.3MPa, and the shear stress is 9.8MPa; the thickness of the 0.5mm spacing cut graphite sheet is 0.3mm, the tensile strength is 10.7MPa, and the shear stress is 4.3MPa.

[0091] 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.

[0092] 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 times is retained for both shear stress and tensile strength at this thickness, thereby improving the overall reliability.

[0093] In some embodiments, the tube body 10 is a circular tube. By configuring the tube body 10 as a circular tube, it is convenient to package 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.

[0094] Specifically, the cross section of the circular tube is circular. When the heating element 20 penetrates the circular tube, the distances between the heating element 20 and various parts of the inner wall of the circular tube are similar, so that the heating element 20 is easier to control.

[0095] In other embodiments, the tube body 10 is a prismatic tube. Specifically, the cross section of the prismatic tube is a prismatic tube.

[0096] In some embodiments, the carbonaceous material includes artificial graphite, natural graphite, and graphene. For example, the carbonaceous material may be artificial graphite, which is characterized by high purity and excellent electrical and thermal conductivity. Alternatively, the carbonaceous material may be natural graphite, which is characterized by good lubricity and wear resistance. Alternatively, the carbonaceous material may be graphene, which is characterized by high electrical and thermal conductivity, as well as high tensile strength and elastic modulus.

[0097] like Figure 4 、 Figure 13 As shown, in some embodiments, connecting terminals 23 are connected to both ends of the length direction of the heating element 20. Each connecting terminal 23 is press-sealed and fixed to the tube body 10, and a portion of the connecting terminal 23 extends out of the tube body 10. By providing the connecting terminals 23 to be press-sealed and fixed to the tube body 10, the heating element 20 is stabilized in the tube body 10.

[0098] Specifically, the compression sealing process is as follows: First, the heater is gently inserted into the tube, ensuring the appropriate amount of extension of the connecting terminals. Then, through methods such as flame heating, the ends of the tube are heated to a molten state. The compression blocks on both sides of the tube are then automatically and rapidly closed, squeezing the molten tube. Once the tube cools, the connecting terminals and the tube are compressed and sealed together, ultimately creating a vacuum seal, completing the process of encapsulating the heater into the tube.

[0099] In some embodiments, the connecting terminal 23 includes a main body 231 and a packaging portion 232. The main body 231 is connected to the heating element 20, and the packaging portion 232 is connected to the main body 231 and is press-sealed and fixed to the tube body 10. The main body 231 and the packaging portion 232 form an angle. By setting the angle between the main body 231 and the packaging portion 232, the probability of problems such as air leakage from the carbon heating tube 100 and cracks in the heating element 20 and the connecting terminal 23 during the press-sealing and fixing of the connecting terminal 23 to the tube body 10 is reduced.

[0100] In the related art, when encapsulating a graphite sheet into a quartz tube, the sheet is inserted into the tube relatively randomly. As the tube cools and solidifies, the graphite sheet is subjected to stress, which may cause the sheet to deform and twist, or it may be squeezed against the inner wall of the tube. Various situations may cause cracks in the graphite sheet, resulting in a low pass rate. The present application provides an angle between the main body 231 and the packaging portion 232. This angle is pre-set between the main body 231 and the packaging portion 232 to improve deformation of the heating element 20 during the cooling and solidification of the tube body 10, reduce the probability of cracks, and improve the packaging manufacturing pass rate.

[0101] In some embodiments, the angle θ between the main body 231 and the packaging portion 232 is 180°. Figure 13 、 Figure 16 As shown, the angle θ is 180°; during parallel packaging, the graphite sheet is parallel to the sealing plane, and the graphite sheet will not be stretched or twisted when inserted; and during melt sealing, the terminals at both ends are not likely to form an uneven molding state with the sealing plane, reducing the generation of cracks in the terminals and air leakage in the sealing tube head.

[0102] In some embodiments, the main body 231 and the packaging portion 232 are arranged perpendicularly. By arranging the main body 231 and the packaging portion 232 perpendicularly, the heating element 20 can be easily inserted into the tube body 10, and it is not easy to be stretched, twisted, or bent to damage the sheet-shaped heating element 20, thereby ensuring the integrity of the packaged heating element 20. At the same time, during the melt-sealing process, the connecting terminal 23 and the tube head of the tube body 10 can be kept parallel, greatly reducing cracks in the connecting terminal 23 and air leakage in the tube head.

[0103] For example, the tube body 10 is a straight tube, and the state of the heating element 20 of the straight tube is as follows: Figure 17 、 Figure 18 As shown, the angle θ is 90°. Before gently inserting the graphite sheet, bend the terminals 90°. This ensures that the neutral plane of the inserted graphite sheet is perpendicular to the neutral plane of the quartz tube head to be formed, and the terminals and the tube head pressure surface are parallel. This vertical packaging of the straight tube is less likely to cause cracks in the terminals and leaks in the tube head, and also prevents stretching and distortion of the graphite sheet.

[0104] Alternatively, the tube body 10 is any one of an annular tube, a U-shaped tube and an S-shaped tube, and the angle θ is 90°, so that the neutral plane F1 and the neutral plane of the tube head of the tube body 10 are perpendicular. Figure 19 、 Figure 20 As shown, when the heating element 20 is inserted into the annular tube, the vertical state with an angle θ of 90° allows the heating element 20 to be easily inserted along the neutral plane of the annular tube, and the heating element 20 is not easily stretched or twisted; when the connecting terminal 23 is melt-sealed, it can also be kept parallel to the tube head of the tube body 10, reducing the cracks in the connecting terminal 23 and the leakage of the sealed tube head. Figure 21 、 Figure 22 As shown, similar to the annular tube, it can also ensure that the heating element 20 can easily pass through the semicircle, ensuring the manufacturing qualification rate during insertion and packaging. Figure 23 、 Figure 24 As shown, similar to the annular tube and the U-shaped tube, the heating element 20 is not easily stretched or twisted when passing through the upper bend 11 of the tube body 10, and at the same time, the tube head rarely leaks or cracks when the connecting terminal 23 is melted and sealed.

[0105] Specifically, the probabilities of various problems occurring in the circular tube of C-1 before process improvement were as follows: graphite flake film breakage 1.13%, graphite flake strain 3.62%, graphite flake sprain 2.83%, graphite flake crease 5.51%, molybdenum flake cracking 6.82%, molybdenum flake wrinkling 6.78%, pressure-sealed bubbles 7.58%, pressure-sealed air leakage 5.31%, and a total of 39.58%; after process improvement, the probabilities of various problems occurring in the circular tube of C-1 were as follows: graphite flake film breakage 0.54%, graphite flake strain 1.45%, graphite flake sprain 2.13%, graphite flake crease 2.55%, molybdenum flake cracking 1.97%, molybdenum flake wrinkling 2.96%, pressure-sealed bubbles 2.65%, pressure-sealed air leakage 1.62%, and a total of 15.87%. The qualified rate before and after improvement was improved by 23.7%.

[0106] Specifically, the probabilities of various problems occurring in the circular tube of C-2 before process improvement were as follows: graphite flake film breakage 1.15%, graphite sheet strain 3.11%, graphite sheet sprain 2.65%, graphite sheet crease 5.16%, molybdenum sheet cracking 6.95%, molybdenum sheet wrinkling 6.12%, pressure-sealed bubbles 7.74%, pressure-sealed air leakage 5.46%, and a total of 38.34%; after process improvement, the probabilities of various problems occurring in the circular tube of C-2 were as follows: graphite flake film breakage 0.52%, graphite sheet strain 1.41%, graphite sheet sprain 2.15%, graphite sheet crease 2.52%, molybdenum sheet cracking 1.82%, molybdenum sheet wrinkling 2.84%, pressure-sealed bubbles 2.53%, pressure-sealed air leakage 1.56%, and a total of 15.35%. The qualified rate was improved by 23.0% before and after improvement.

[0107] Specifically, the probabilities of various problems occurring in the U-shaped tube of U-1 before process improvement were as follows: graphite flake film breakage 1.12%, graphite flake strain 3.82%, graphite flake sprain 2.74%, graphite flake crease 5.37%, molybdenum flake cracking 6.72%, molybdenum flake wrinkling 6.25%, pressure-sealed bubbles 7.32%, pressure-sealed air leakage 4.9%, and a total of 38.24%; after process improvement, the probabilities of various problems occurring in the U-shaped tube of U-1 were as follows: graphite flake film breakage 0.52%, graphite flake strain 1.43%, graphite flake sprain 2.16%, graphite flake crease 2.47%, molybdenum flake cracking 1.94%, molybdenum flake wrinkling 2.94%, pressure-sealed bubbles 2.42%, pressure-sealed air leakage 1.51%, and a total of 15.39%. The qualified rate was improved by 22.9% before and after improvement.

[0108] Specifically, the probabilities of various problems occurring in the S-shaped tube of S-1 before process improvement were as follows: graphite flake film breakage 1.10%, graphite flake strain 3.78%, graphite flake sprain 2.81%, graphite flake crease 5.11%, molybdenum flake cracking 6.42%, molybdenum flake wrinkling 6.85%, pressure-sealed bubbles 7.12%, pressure-sealed air leakage 4.77%, and a total of 37.96%; after process improvement, the probabilities were as follows: graphite flake film breakage 0.51%, graphite flake strain 1.46%, graphite flake sprain 2.18%, graphite flake crease 2.49%, molybdenum flake cracking 1.81%, molybdenum flake wrinkling 2.87%, pressure-sealed bubbles 2.42%, pressure-sealed air leakage 1.55%, and a total of 15.29%. The qualified rate before and after improvement was improved by 22.7%.

[0109] Specifically, the probabilities of various problems occurring in the S-shaped tube of S-1 before process improvement were as follows: graphite flake film breakage 1.11%, graphite flake strain 3.73%, graphite flake sprain 2.92%, graphite flake crease 5.05%, molybdenum flake cracking 6.38%, molybdenum flake wrinkling 6.81%, pressure-sealed bubbles 7.04%, pressure-sealed air leakage 4.63%, and a total of 37.67%; after process improvement, the probabilities of various problems occurring in the S-shaped tube of S-1 were as follows: graphite flake film breakage 0.58%, graphite flake strain 1.41%, graphite flake sprain 2.20%, graphite flake crease 2.41%, molybdenum flake cracking 1.86%, molybdenum flake wrinkling 2.81%, pressure-sealed bubbles 2.34%, pressure-sealed air leakage 1.48%, and a total of 15.09%. The qualified rate before and after improvement was improved by 22.6%.

[0110] In summary, the defective proportion of carbon heating tubes has dropped significantly, and the overall qualified rate has increased by about 23%.

[0111] The following combination Figures 1 to 24 , describing a specific embodiment of the carbon heating tube 100 of the present invention.

[0112] A carbon heating tube 100 includes a tube body 10 and a heating element 20 .

[0113] 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. The bending portion 11 is formed in an arc shape. The defined reference line passes through the center of the bending portion 11 and is perpendicular to the radius direction of the bending portion 11.

[0114] The heating element 20 is a sheet of carbonaceous material, inserted into the tube body 10. It comprises a plurality of heating units 22 arranged sequentially along the length. Each heating unit 22 is formed as a curved segment with its opening facing in the first direction. Adjacent heating units 22 are connected by a connecting piece, which is connected to the end of the curved segment. Each heating unit 22 comprises two parallel heating side walls 221. The spacing between the two heating side walls 221 is a first spacing L1, and the gap between adjacent heating units 22 is a second spacing L2. The first spacing L1 and the second spacing L2 are equal. The first spacing L1 is 0.5 mm, and the thickness of the heating element 20 is 0.2 mm.

[0115] Connecting terminals 23 are connected to both ends of the heating element 20 in the longitudinal direction. Each connecting terminal 23 is press-sealed and fixed to the tube body 10, and a portion of the connecting terminal 23 extends out of the tube body 10. The connecting terminal 23 includes a main body 231 and a packaging portion 232. The main body 231 is connected to the heating element 20, and the packaging portion 232 is connected to the main body 231 and press-sealed and fixed to the tube body 10. The main body 231 and the packaging portion 232 are arranged vertically.

[0116] The heating element 20 has a central neutral plane F1 along its thickness. The neutral plane F1 extends along the length of the tube 10, and at least the portion of the neutral plane F1 directly opposite the bend 11 is parallel to the reference line. The central axis of the bend 11 has a radius of curvature R1, and the portion of the neutral plane F1 directly opposite the bend 11 has a radius of curvature R2, where R2 / R1 equals 1.

[0117] The cooking device according to the embodiment of the present invention includes the carbon heating tube 100 described above.

[0118] According to the cooking device of the embodiment of the present invention, at least the portion of the neutral plane F1 that is opposite to the bending portion 11 is arranged parallel to the reference line, so that the heating element 20 will not be distorted by external forces, and the heating element 20 can smoothly penetrate into the tube body 10, thereby improving the yield rate, greatly improving production efficiency, and saving costs.

[0119] In some embodiments, the cooking device includes: a box, a drawer, and a carbon heating tube 100 .

[0120] A drawer opening is provided on the front side of the box.

[0121] The drawer is used for holding food, and the drawer can be drawn relative to the box body through the drawer opening.

[0122] The carbon heating tube 100 is disposed in the box to heat the interior of the box.

[0123] Among them, the pull-out piece is used to hold food. Compared with the solution in the related art that the food carrying space is fixed in the cooking appliance, this application makes it convenient to place and take out food.

[0124] For example, the cooking device is an oven; or, the cooking device is an air fryer; or, the cooking device is a microwave oven.

[0125] Other structures and operations of the carbon heating tube 100 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0126] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0127] In addition, features defined as "first" or "second" may explicitly or implicitly include one or more such features, and are used to distinguish and describe features, without any distinction in order or importance.

[0128] In the description of the present invention, unless otherwise specified, “a plurality of” means two or more.

[0129] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0130] Throughout this specification, references to terms such as "embodiment" and "example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0131] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A carbon heating tube, characterized in that: include: A hollow tube having at least one bend, wherein the bend is formed in an arc shape, and a reference line is defined passing through the center of the bend and perpendicular to the radius of the bend; A heating element, wherein the heating element is formed as a sheet of carbonaceous material, and the heating element is inserted into the tube body. In the thickness direction of the heating element, the heating element has a neutral plane located in the center, and the neutral plane extends along the length direction of the tube body. At least the part of the neutral plane that is opposite to the bending portion is arranged parallel to the reference line.

2. The carbon heating tube according to claim 1, characterized in that: The curvature radius of the central axis of the bending portion is R1, the curvature radius of the portion of the neutral plane directly opposite to the bending portion is R2, and 0.95≤(R2 / R1)≤1.

05.

3. The carbon heating tube according to claim 1, characterized in that: The heating element includes a plurality of heating units sequentially arranged along the length direction, each of the heating units is formed as a curved section with an opening facing the first direction, and adjacent heating units are connected via a connecting piece.

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

5. The carbon heating tube according to claim 3, characterized in that: Each of the heating units includes two parallel heating side walls, the distance between the two heating side walls is a first distance, the gap between adjacent heating units is a second distance, and the first distance is the same as the second distance.

6. The carbon heating tube according to claim 5, characterized in that: The first spacing is 0.5 mm, and the thickness of the heating element ranges from [0.1 mm to 0.3 mm].

7. The carbon heating tube according to claim 6, characterized in that: The thickness of the heating element is 0.2 mm.

8. The carbon heating tube according to claim 1, characterized in that: The tube body is a circular tube.

9. The carbon heating tube according to any one of claims 1 to 8, characterized in that: The carbonaceous material pieces include artificial graphite pieces, natural graphite pieces and graphene material pieces.

10. The carbon heating tube according to any one of claims 1 to 8, characterized in that: Both ends of the heating element in the length direction are connected with connecting terminals. Each of the connecting terminals is sealed and fixed to the tube body, and a part of the connecting terminal extends out of the tube body.

11. The carbon heating tube according to claim 10, characterized in that: The connecting terminal includes a main body and a packaging part. The main body is connected to the heating element. The packaging part is connected to the main body and is press-sealed and fixed to the tube body. The main body and the packaging part form an angle.

12. The carbon heating tube according to claim 11, characterized in that: The main body portion and the packaging portion are vertically arranged.

13. A cooking device, characterized in that: The carbon heating tube comprises the carbon heating tube according to any one of claims 1 to 12.

14. The cooking device according to claim 13, wherein The cooking device comprises: A box body, wherein a drawer opening is provided on the front side of the box body; a drawer for holding food, the drawer being drawable relative to the box body through the drawer opening; A carbon heating tube is provided in the box to heat the interior of the box.

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