Graphite heating pipe with reliable structure

Abstract

The utility model belongs to the technical field of heating tools, and discloses a graphite heating tube with a reliable structure, which comprises a glass tube and a graphite flake arranged in the glass tube, the glass tube comprises a bending section and a press sealing section connected to the end part of the bending section, the graphite flake is positioned in the bending section and is connected with an electric connecting rod, and the electric connecting rod is connected with the graphite flake. The electric connecting rod penetrates out of the press sealing section, and the axis a of the electric connecting rod deflects towards the bending center O of the bending section relative to the center line b of the end of the bending section. According to the graphite heating pipe provided by the utility model, the electric connecting rod can share certain stress for the graphite sheet by adjusting the position of the electric connecting rod and improving the matching property between the electric connecting rod and the bending section, so that the deformation quantity of the end part of the graphite sheet is reduced, the stress concentration of the end part of the graphite sheet is avoided, the stress of the end part of the graphite sheet is reduced, and the service life of the graphite sheet is prolonged. The fracture risk caused by cold and hot expansion after long-term use of the graphite heating pipe is avoided, and the service life of the graphite heating pipe is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of heating tools, and in particular relates to a graphite heating tube with reliable structure. Background Art

[0002] Common heating tubes in existing home appliances are generally carbon fiber heating tubes and graphite heating tubes. Among them, carbon fiber heating tubes are made by weaving carbon fibers, adding resin to the surface and firing at high temperature. They have a certain toughness, so curved and special-shaped heating tubes can be prepared. The graphite sheets in graphite heating tubes have higher purity than carbon fibers, and have technical advantages such as strong penetration, fast heating, and good baking effect, but the toughness of graphite sheets is poor.

[0003] The utility model patent with application number 202120767893.8 discloses a special-shaped graphite heating tube, a hot air system and a cooking utensil. The special-shaped graphite heating tube includes: a glass tube, a fixing part is provided at the end of the glass tube; a graphite sheet, the graphite sheet is arranged in the glass tube; a wiring terminal, the wiring terminal is arranged at the end of the graphite sheet and connected to the fixing part. The special-shaped graphite heating tube is constructed into an arc structure. The special-shaped graphite heating tube can save installation space, reduce product volume and improve heating uniformity.

[0004] However, due to the poor toughness of the graphite sheet, during the process of assembling the graphite sheet and the arc-shaped tube, the graphite sheet is easily damaged by bending, pulling, etc., making installation difficult. Moreover, since the molybdenum rod connected to the end of the graphite sheet is a rigid material, there is internal stress in the graphite sheet at the end of the glass tube, including stress caused by the curvature of the graphite sheet during installation and thermal stress caused by thermal expansion and contraction when the heating tube is powered on and off. When the curvature of the graphite sheet, the molybdenum rod and the arc-shaped tube cannot be completely matched, the contact part between the molybdenum rod and the graphite sheet, that is, the end of the graphite sheet, will easily produce large deformation and generate stress. During long-term use, the thermal expansion and contraction of the graphite sheet will cause the product to be at risk of breakage, affecting its service life. Utility Model Content

[0005] The utility model provides a graphite heating tube with reliable structure, which solves the technical problem that the graphite sheet is easily broken at the end after being installed in a curved glass tube.

[0006] The technical solution adopted by the utility model is:

[0007] The utility model provides a graphite heating tube with reliable structure, comprising a glass tube and a graphite sheet arranged in the glass tube, the glass tube comprising a bending section and a pressure-sealed section connected to the end of the bending section, the graphite sheet is located in the bending section and is connected to an electric connecting rod, the electric connecting rod passes through the pressure-sealed section, and the axis a of the electric connecting rod is deflected toward the bending center O of the bending section relative to the center line b of the end of the bending section.

[0008] The utility model provides a graphite heating tube, wherein the graphite sheet is located in the curved section and connected to the electric connecting rod, the electric connecting rod passes through the compression seal section and is compression-sealed and fixed by a process, and the graphite sheet is encapsulated in the glass tube, and the axis a of the electric connecting rod is deflected relative to the center line b of the end of the curved section toward the bending center O of the curved section, that is, the position of the electric connecting rod is adjusted to improve the matching between the electric connecting rod and the curved section, and the electric connecting rod can share a certain amount of force for the graphite sheet, thereby reducing the deformation amount of the end of the graphite sheet, avoiding stress concentration at the end of the graphite sheet, reducing the stress at the end of the graphite sheet, avoiding the risk of fracture caused by long-term use of the graphite heating tube due to cold and hot expansion, and extending the service life of the graphite heating tube. Since the glass tube includes a curved section and a compression seal section connected to the end of the curved section, the curved section is conducive to reducing the volume, so as to save installation space, so as to be applicable to household appliances of different volumes, and has a wide range of uses. Moreover, since the curved section is provided to accommodate the graphite sheet, the heating uniformity can be improved compared with the straight heating tube, and the compression seal section and the curved section cooperate to achieve the sealing of the heating tube during the processing, and the structure is reliable.

[0009] In a preferred embodiment, the deflection angle between the axis a of the electrical connecting rod and the center line b of the end of the bending section is α, 0<α≤5°.

[0010] Since the inner diameter of the glass tube is limited, by limiting the deflection angle α to below 5°, on the one hand, it can avoid the position of the electric connecting rod being too close to the side wall of the glass tube, causing installation interference and unreliable connection problems. On the other hand, it can prevent the electric connecting rod from being directly broken during the assembly process due to excessive deflection. Therefore, satisfying 0<α≤5° can further extend the service life of the graphite heating tube and enhance the structural reliability.

[0011] In a preferred embodiment, the axis a of the electrical connecting rod is deflected toward the bending center O of the glass tube relative to the center line c of the end of the graphite sheet.

[0012] By deflecting the axis a of the electric connecting rod relative to the center line c of the end of the graphite sheet toward the bending center O of the glass tube, the electric connecting rod and the arc segment can be adaptively matched, and the bending degree of the electric connecting rod and the graphite sheet can be matched, thereby reducing the risk of breakage of the graphite sheet and the electric connecting rod and extending the service life.

[0013] In a preferred embodiment, the deflection angle between the axis a of the electrical connecting rod and the center line c of the end of the graphite sheet is β, 0<β≤5°.

[0014] Since the inner diameter of the glass tube is limited, by limiting the deflection angle β to less than 5°, on the one hand, it can prevent the position of the electric connecting rod from being too close to the side wall of the glass tube, causing installation interference and unreliable connection problems; on the other hand, it can prevent the electric connecting rod from being directly broken during the assembly process due to excessive deflection, thereby extending the service life of the graphite heating tube and enhancing the structural reliability.

[0015] In a preferred embodiment, the axis a of the electrical connecting rod is deflected inwardly relative to the center line of the compression seal section.

[0016] By deflecting the axis a of the electrical connecting rod inward relative to the center line of the compression sealing section, that is, adjusting the position between the electrical connecting rod and the compression sealing section, the electrical connecting rod can more directly share the force for the graphite sheet during and after the compression sealing process, thereby avoiding stress concentration at the end of the graphite sheet and extending the service life of the graphite heating tube.

[0017] In a preferred embodiment, the compression seal section is a straight section extending along a straight line, and the axis a of the electrical connecting rod is parallel to the center line d of the straight section.

[0018] By setting the sealing section as a straight section extending along a straight line and making the axis a of the electrical connecting rod parallel to the center line d of the straight section, the matching between the sealing section and the electrical connecting rod is further improved, the stress of the graphite sheet at the end is reduced, and the service life of the heating tube is extended.

[0019] In a preferred embodiment, the compression sealing section is an arc section formed by extending the bending section.

[0020] By arranging the compression sealing section as an arc section extended from the bending section, the forming process of the glass tube can be simplified, the cost can be reduced, and the application is wide.

[0021] In a preferred embodiment, a press-sealed molybdenum sheet is provided in the press-sealed section, and the electrical connecting rod includes a first rod body connected between the end of the graphite sheet and the press-sealed molybdenum sheet, the first rod body includes a second connecting section press-sealed in the press-sealed section and a first connecting section connected between the second connecting section and the end of the graphite sheet, and the length L1 of the first connecting section and the length L2 of the second connecting section satisfy: L1 / L2≤2.

[0022] By setting the length L1 of the first connecting section and the length L2 of the second connecting section to L1 / L2≤2, that is, the portion of the electrical connecting rod that is not sealed to the sealing section can occupy more than 2 / 3 of the entire first rod body, so as to better improve the curvature matching between the electrical connecting rod and the glass tube, reduce the stress at the end of the graphite sheet, and extend the service life.

[0023] In a preferred embodiment, a press-sealed molybdenum sheet is provided in the press-sealed section, and the electrical connecting rod comprises a first rod body connected between the end of the graphite sheet and the press-sealed molybdenum sheet, and the length of the first rod body is L0, 15mm≤L0≤25mm.

[0024] By setting the length of the first rod body to 15mm-25mm, the problem of inconvenience in installation and operation when the length is less than 15mm and difficulty in operation is avoided, and the problem of poor matching between the electrical connecting rod and the glass tube when the length is too small, and the waste of materials caused by excessive length is avoided. Therefore, satisfying 15mm≤L0≤25mm can save materials, simplify installation operations, and improve the matching between the electrical connecting rod and the glass tube.

[0025] In a preferred embodiment, the graphite sheet includes a wide sub-portion and a narrow sub-portion, the wide sub-portion and the narrow sub-portion are alternately connected along the length direction of the graphite sheet, the width of the wide sub-portion is W, the narrow sub-portion includes a first sub-portion and a second sub-portion, the first sub-portion is closer to the end of the graphite sheet than the second sub-portion, the widths of the first sub-portion and the second sub-portion are W1 and W2 respectively, satisfying: 0.7W>W1>W2>0.1W.

[0026] By setting the graphite sheet to include a wide sub-section and a narrow sub-section, the wide sub-section and the narrow sub-section are alternately connected along the length direction of the graphite sheet. For the narrow sub-section, the wider the width, the stronger the rigidity, and the narrower the width, the stronger the flexibility. Therefore, the widths of the first section and the second section are W1 and W2 respectively, and flexibility changes are achieved, so that the graphite sheet can have a certain flexibility for easy bending, and at the same time have good structural strength. The first section is closer to the end of the graphite sheet than the second section, and W1>W2. Therefore, a uniform transition from the end of the graphite sheet to the center is achieved to reduce the stress at the end of the graphite sheet and avoid fracture. 0.7W>W1>W2>0.1W is satisfied, which can avoid the narrow sub-section being too large and not conducive to excessive flexibility to the center. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of the structure of the graphite heating tube in Example 1;

[0029] Figure 2 for Figure 1 The partial enlarged view of the middle A portion shows the deflection direction and deflection angle of the electrical connecting rod;

[0030] Figure 3 for Figure 1The partial enlarged view of the middle A part shows the specific structure of the electric connecting rod;

[0031] Figure 4 This is a schematic diagram of the structure of the graphite sheet in Example 1;

[0032] Figure 5 A schematic diagram of a molding process in an embodiment of Example 1;

[0033] Figure 6 A schematic diagram of a molding process in another embodiment of Example 1;

[0034] Figure 7 This is a schematic diagram of the partial structure of the graphite heating tube in Example 2;

[0035] Explanation of the reference numerals: 10, glass tube; 11, bending section; 12, pressure-sealed section; 20, graphite sheet; 21, wide subsection; 22, narrow subsection; 221, first subsection; 222, second subsection; 30, electrical connecting rod; 31, first rod body; 311, first connecting section; 312, second connecting section; 32, second rod body; 40, pressure-sealed molybdenum sheet; 50, high-pressure gas nozzle; 60, musket; 70, fire baffle. DETAILED DESCRIPTION

[0036] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in the form of examples in conjunction with the accompanying drawings.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below. It should be noted that the embodiments of the present invention and the features in each embodiment may be combined with each other without conflict.

[0038] In addition, in the description of the present invention, it should be understood that the terms "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating orientations or positional relationships, are 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 cannot be understood as a limitation on the present invention.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present utility model, unless otherwise clearly specified and limited, the first feature "above" or "below" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0041] like Figure 1-6 As shown, the utility model provides a graphite heating tube with reliable structure in implementation example 1, including a glass tube 10 and a graphite sheet 20 arranged in the glass tube 10, the glass tube 10 includes a bending section 11 and a pressure-sealed section 12 connected to the end of the bending section 11, the graphite sheet 20 is located in the bending section 11 and is connected to an electrical connecting rod 30, the electrical connecting rod 30 passes through the pressure-sealed section 12, and the axis a of the electrical connecting rod 30 is deflected toward the bending center O of the bending section 11 relative to the center line b of the end of the bending section 11, that is, Figure 2 The hollow arrows shown deflect in the direction indicated.

[0042] Optionally, the electrical connecting rod 30 is a molybdenum rod.

[0043] More preferably, the deflection angle between the axis a of the electrical connection rod 30 and the center line b of the end of the curved section 11 is α, 0<α≤5°. Specifically, α can be selected as 1°, 2°, 3°, 4°, 5°.

[0044] The graphite heating tube provided in this embodiment and the conventional graphite heating tube were subjected to a 1.3 times voltage accelerated life test, and the test results are as follows: In Example 1, no abnormal fracture was found in the graphite heating tube during the 1.3 times voltage accelerated life test for 400 hours; the conventional graphite heating tube was found to be fractured around 30 hours after the 1.3 times voltage accelerated life test. According to the standard GBT 7287-2008, the nominal working life is 5000 hours after the 1.3 times voltage accelerated life test for 60 hours.

[0045] Therefore, in the graphite heating tube provided in this embodiment, the graphite sheet 20 is located in the bending section 11 and is connected to the electric connecting rod 30. The electric connecting rod 30 passes through the compression sealing section 12 and is compression-sealed and fixed by a process. At the same time, the graphite sheet 20 is encapsulated in the glass tube 10, and the axis a of the electric connecting rod 30 is deflected toward the bending center O of the bending section 11 relative to the center line b of the end of the bending section 11, that is, the position of the electric connecting rod 30 is adjusted to improve the matching between the electric connecting rod 30 and the bending section 11. The electric connecting rod 30 can share a certain amount of force for the graphite sheet 20, thereby reducing the deformation amount at the end of the graphite sheet 20, avoiding stress concentration at the end of the graphite sheet 20, reducing the stress at the end of the graphite sheet 20, avoiding the risk of fracture caused by hot and cold expansion of the graphite heating tube during long-term use, and extending the service life of the graphite heating tube. Since the glass tube 10 includes a curved section 11 and a compression-sealed section 12 connected to the end of the curved section 11, the curved section 11 is conducive to reducing the volume to save its installation space so that it is suitable for household appliances of different volumes. For example, the graphite heating tube provided in this embodiment can be optionally used in household appliances such as air fryers and water kettles, and has a wide range of uses. Moreover, since the curved section 11 is provided to accommodate the graphite sheet 20, the heating uniformity can be improved compared with a straight heating tube. The compression-sealed section 12 and the curved section 11 cooperate to achieve the sealing of the heating tube during the processing, and the structure is reliable.

[0046] Since the inner diameter of the glass tube 10 is limited, by limiting the deflection angle α to below 5°, on the one hand, it can prevent the position of the electrical connecting rod 30 from being too close to the side wall of the glass tube 10, causing installation interference and unreliable connection problems. On the other hand, it can prevent the electrical connecting rod 30 from being excessively deflected and directly broken during the assembly process. Therefore, satisfying 0<α≤5° can further extend the service life of the graphite heating tube and enhance the structural reliability.

[0047] In a preferred embodiment, the axis a of the electrical connecting rod 30 is deflected toward the bending center O of the glass tube 10 relative to the center line c of the end of the graphite sheet 20. More preferably, the deflection angle between the axis a of the electrical connecting rod 30 and the center line c of the end of the graphite sheet 20 is β, 0<β≤5°. β can be selected from 1°, 2°, 3°, 4°, 5°.

[0048] Specifically, Figure 2As shown, in a preferred embodiment, the center line c of the end of the graphite sheet 20 coincides with the center line b of the end of the curved section 11, so β=α. Of course, it can be understood that in other embodiments, the graphite sheet 20 may have a certain deflection during the installation process, so the center line c of the end of the graphite sheet 20 may not coincide with the center line b of the end of the curved section 11.

[0049] By deflecting the axis a of the electric connecting rod 30 relative to the center line c of the end of the graphite sheet 20 toward the bending center O of the glass tube 10, the electric connecting rod 30 can be adaptively matched with the arc segment while also matching the bending degree of the graphite sheet 20, thereby reducing the risk of fracture of the graphite sheet 20 and the electric connecting rod 30 and extending the service life. Similarly, since the inner diameter of the glass tube 10 is limited, by limiting the deflection angle β to less than 5°, on the one hand, the position of the electric connecting rod 30 is prevented from being too close to the side wall of the glass tube 10, causing installation interference and unreliable connection problems, and on the other hand, it can prevent the electric connecting rod 30 from being directly broken during the assembly process due to excessive deflection, thereby extending the service life of the graphite heating tube and having strong structural reliability.

[0050] In a preferred embodiment, referring to Figure 2 , the axis a of the electrical connecting rod is deflected inwardly relative to the center line e of the pressure sealing section.

[0051] By deflecting the axis a of the electrical connecting rod inward relative to the center line of the compression sealing section, that is, adjusting the position between the electrical connecting rod and the compression sealing section, the electrical connecting rod can more directly share the force for the graphite sheet during and after the compression sealing process, thereby avoiding stress concentration at the end of the graphite sheet and extending the service life of the graphite heating tube.

[0052] The utility model does not limit the specific form of the compression seal section, for example:

[0053] Implementation example 1, such as Figure 1-6 As shown, the compression seal section 12 is an arc section formed by extending the curved section 11. By setting the compression seal section 12 as an arc section formed by extending the curved section 11, the forming process of the glass tube 10 can be simplified, the cost can be reduced, and the application is wide.

[0054] Implementation Example 2, such as Figure 7 As shown, the compression seal section 12 is a straight section extending along a straight line; more preferably, the axis a of the electrical connection rod 30 is parallel to the center line d of the straight section.

[0055] By setting the compression seal section 12 as a straight section extending along a straight line, the matching between the compression seal section 12 and the electrical connecting rod 30 can be improved, the stress of the graphite sheet 20 at the end can be reduced, and the service life of the heating tube can be extended. The axis a of the electrical connecting rod 30 is parallel to the center line d of the straight section to further improve the matching between the compression seal section 12 and the electrical connecting rod 30, reduce the stress of the graphite sheet 20 at the end, and extend the service life of the heating tube.

[0056] In a preferred embodiment, Figure 3 As shown, a press-sealed molybdenum sheet 40 is provided in the press-sealed section 12, and the electrical connecting rod 30 includes a first rod body 31 connected between the end of the graphite sheet 20 and the press-sealed molybdenum sheet 40 and a second rod body 32 connected to the press-sealed molybdenum sheet 40 and extending out of the press-sealed section. The first rod body 31 includes a second connecting section 312 press-sealed in the press-sealed section 12 and a first connecting section 311 connected between the second connecting section 312 and the end of the graphite sheet 20. The length L1 of the first connecting section 311 and the length L2 of the second connecting section 312 satisfy: L1 / L2≤2.

[0057] By setting the length L1 of the first connecting section 311 and the length L2 of the second connecting section 312 to L1 / L2≤2, that is, the portion of the electrical connecting rod 30 that is not sealed to the sealing section 12 can occupy more than 2 / 3 of the entire first rod body 31, so as to better improve the curvature matching between the electrical connecting rod 30 and the glass tube 10, reduce the stress at the end of the graphite sheet 20, and extend the service life.

[0058] In a preferred embodiment, Figure 3 As shown, a press-sealed molybdenum sheet 40 is provided in the press-sealed section 12, and the electrical connecting rod 30 includes a first rod body 31 connected between the end of the graphite sheet 20 and the press-sealed molybdenum sheet 40, and the length of the first rod body 31 is L0, 15mm≤L0≤25mm.

[0059] By setting the length of the first rod body 31 to 15 mm-25 mm, the problem of inconvenience in installation and operation when the length is less than 15 mm, the problem of poor matching between the electrical connecting rod 30 and the glass tube 10 when the length is too small, and the waste of materials caused by excessive length are avoided. Therefore, satisfying 15 mm ≤ L0 ≤ 25 mm can save materials, simplify the installation operation, and improve the matching between the electrical connecting rod 30 and the glass tube 10.

[0060] The utility model does not limit the specific structure of the graphite sheet. For example, in Example 1, Figure 4As shown, the graphite sheet 20 includes a wide sub-portion 21 and a narrow sub-portion 22, and the wide sub-portion 21 and the narrow sub-portion 22 are alternately connected along the length direction of the graphite sheet 20. The width of the wide sub-portion 21 is W, and the narrow sub-portion 22 includes a first sub-portion 221 and a second sub-portion 222. The first sub-portion 221 is closer to the end of the graphite sheet 20 than the second sub-portion 222. The widths of the first sub-portion 221 and the second sub-portion 222 are W1 and W2, respectively, satisfying: 0.7W>W1>W2>0.1W.

[0061] By setting the graphite sheet 20 to include a wide sub-portion 21 and a narrow sub-portion 22, the wide sub-portion 21 and the narrow sub-portion 22 are alternately connected along the length direction of the graphite sheet 20. For the narrow sub-portion 22, the wider the width, the stronger the rigidity, and the narrower the width, the stronger the flexibility. Therefore, the widths of the first section 221 and the second section 222 are W1 and W2, respectively, to achieve flexibility change. The first section 221 is closer to the end of the graphite sheet 20 than the second section 222, and W1>W2. Therefore, a uniform transition from the end of the graphite sheet 20 to the center is achieved to reduce the stress at the end of the graphite sheet 20 and avoid fracture. 0.7W>W1>W2>0.1W is satisfied, which can avoid the narrow sub-portion 22 being too large and not conducive to excessive flexibility to the center.

[0062] It should also be noted that, generally, the bent glass tube end is softened by a torch, and then the mold is pressed together to achieve sealing, forming a press-sealed section. The temperature of the high-temperature flame is nearly 2000°C to achieve the softening and molding of the quartz glass. In addition, the effect of high-pressure gas leads to a large heat-affected zone, and the graphite sheet at the end is easily damaged by heat, changing the resistor structure, and then abnormal heating during operation affects the service life.

[0063] Therefore, the forming process of the graphite heating tube in the utility model can be optionally as follows: Figure 5 As shown, local cooling is formed by adding high-pressure air in the pressure sealing section. The high-pressure air is preferably inert gas such as nitrogen and argon to avoid oxidation of parts under high temperature conditions. The air pressure is 0.3-0.6MPa. The distance S between the high-pressure air nozzle 50 and the lance 60 satisfies 18mm<S<30mm to reduce the heat affected zone. The heat affected zone is as shown in FIG. Figure 5 By setting 18mm<S<30mm, it is possible to avoid the situation where the heat affected zone is not changed significantly due to a too large distance, and the pressure sealing effect is affected or even the flame is blown out due to a too small distance.

[0064] like Figure 6 As shown, the forming process of the graphite heating tube in the utility model can optionally be to use a fire baffle 70 to avoid thermal damage to the graphite sheet in the heat-affected zone during the sealing process. The distance between the fire baffle 70 and the blast gun 60 is S2, 18mm<S2<30mm, to ensure that the resistance structure of the graphite sheet does not change, heat is evenly generated during the working process, and the service life is extended.

[0065] The parts not described in the present invention can be realized by adopting or drawing on the existing technology.

[0066] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0067] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A graphite heating tube with reliable structure, comprising a glass tube and a graphite sheet arranged in the glass tube, characterized in that: The glass tube includes a bending section and a compression-sealing section connected to the end of the bending section. The graphite sheet is located in the bending section and is connected to an electrical connecting rod. The electrical connecting rod passes through the compression-sealing section, and the axis a of the electrical connecting rod is deflected toward the bending center O of the bending section relative to the center line b of the end of the bending section.

2. A graphite heating tube with a reliable structure according to claim 1, characterized in that: The deflection angle between the axis a of the electrical connecting rod and the center line b of the end of the bending section is α, 0<α≤5°.

3. A graphite heating tube with reliable structure according to claim 1, characterized in that: The axis a of the electrical connecting rod is deflected toward the bending center O of the glass tube relative to the center line c of the end of the graphite sheet.

4. A graphite heating tube with reliable structure according to claim 3, characterized in that: The deflection angle between the axis a of the electrical connecting rod and the center line c of the end of the graphite sheet is β, 0<β≤5°.

5. A graphite heating tube with reliable structure according to claim 1, characterized in that: The axis a of the electrical connecting rod is deflected inwardly relative to the center line of the compression seal section.

6. A graphite heating tube with reliable structure according to claim 1, characterized in that: The compression seal section is a straight section extending along a straight line, and the axis a of the electrical connecting rod is parallel to the center line d of the straight section.

7. A graphite heating tube with a reliable structure according to claim 1, characterized in that: The compression sealing section is an arc section formed by extending the bending section.

8. A graphite heating tube with a reliable structure according to claim 1, characterized in that: A press-sealed molybdenum sheet is provided in the press-sealed section, and the electrical connecting rod includes a first rod body connected between the end of the graphite sheet and the press-sealed molybdenum sheet, the first rod body includes a second connecting section press-sealed in the press-sealed section and a first connecting section connected between the second connecting section and the end of the graphite sheet, and the length L1 of the first connecting section and the length L2 of the second connecting section satisfy: L1 / L2≤2.

9. A graphite heating tube with a reliable structure according to claim 1, characterized in that: A press-sealed molybdenum sheet is provided in the press-sealed section, and the electrical connecting rod comprises a first rod body connected between the end of the graphite sheet and the press-sealed molybdenum sheet, and the length of the first rod body is L0, 15mm≤L0≤25mm.

10. A graphite heating tube with reliable structure according to claim 1, characterized in that: The graphite sheet includes a wide sub-portion and a narrow sub-portion, wherein the wide sub-portion and the narrow sub-portion are alternately connected along the length direction of the graphite sheet, the width of the wide sub-portion is W, and the narrow sub-portion includes a first sub-portion and a second sub-portion, wherein the first sub-portion is closer to the end of the graphite sheet than the second sub-portion, and the widths of the first sub-portion and the second sub-portion are W1 and W2 respectively, satisfying: 0.7W>W1>W2>0.1W.

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