Dewaxing tube structure of sintering furnace

Abstract

This invention relates to the field of dewaxing tube technology for sintering furnaces, specifically a dewaxing tube structure for sintering furnaces, comprising: a lower graphite dewaxing tube, one end of which is threaded to the outer wall of a mounting flange, and the other end passing through a carbon felt insulation cylinder, with a ball-head sealing surface on its inner side for movable sealing with the lower graphite dewaxing tube; an upper graphite dewaxing tube located above the lower graphite dewaxing tube, one end of which slides through a graphite box and is fixedly installed with a first sealing ball head corresponding to the ball-head sealing surface, the first sealing ball head being inserted into the ball-head sealing surface to form a ball-head sealing pair; the two-section structure and the double ball-head sealing pair are equivalent to a universal joint, so even if the lower graphite dewaxing tube is not installed vertically due to furnace body or flange processing and welding errors, the upper graphite dewaxing tube can be automatically corrected by swinging the double ball heads, smoothly aligning with the graphite box, making installation convenient.

Description

Technical Field

[0001] This invention relates to the field of dewaxing tube technology for sintering furnaces, specifically to a dewaxing tube structure for sintering furnaces. Background Technology

[0002] A sintering furnace is a specialized piece of equipment used to sinter powder compacts to obtain the desired physical and mechanical properties and microstructures. It is widely used in industries such as powder metallurgy, cemented carbide, and magnetic materials. In the forming process, powder compacts usually contain forming agents such as paraffin wax. Before sintering, the forming agents need to be removed during the dewaxing stage. The dewaxing tube device is a key component in the inner liner of the sintering furnace that performs the function of removing wax.

[0003] In the prior art, the dewaxing tube device of the sintering furnace adopts a single graphite dewaxing tube, the lower part of which is threadedly connected and sealed to the lower extraction pipe, and the upper part is pressed and sealed to the plane of the graphite box.

[0004] However, the existing technology has the following defects: 1. Due to the processing and welding errors of the furnace body and the flange of the lower extraction pipe, the perpendicularity of the graphite dewaxing tube and the lower extraction pipe after threaded connection cannot be guaranteed, resulting in deviation in the fit between the graphite tube and the graphite box, making installation difficult; 2. When the temperature rises during the dewaxing stage (below 600℃), the graphite dewaxing tube expands due to heat, and gaps appear in the original flat and tightly sealed cover, causing paraffin vapor to leak out or back-seep in, which seriously affects the dewaxing and sintering quality of the product. 3. When disassembling the graphite box, the graphite dewaxing tube must be removed first. However, the threaded connection will be stuck together by impurities after long-term high-temperature sintering, making disassembly extremely difficult and easily breaking the threaded part of the graphite tube, increasing maintenance time. Summary of the Invention

[0005] The purpose of this invention is to provide a dewaxing tube structure for a sintering furnace, so as to solve the problems mentioned in the background art, such as inconvenient installation, easy leakage when heated, and difficult disassembly of existing dewaxing tubes.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a dewaxing tube structure for a sintering furnace, comprising: The graphite dewaxing tube has one end threaded to the outer wall of the mounting flange, and the other end passes through the carbon felt insulation cylinder. Its inner side is provided with a ball head sealing surface for movable sealing with the graphite dewaxing tube. An upper graphite dewaxing tube is located above the lower graphite dewaxing tube. One end of the upper graphite dewaxing tube slides through the graphite box and is fixedly installed with a first sealing ball head corresponding to the ball head sealing surface. The first sealing ball head is inserted into the ball head sealing surface and forms a ball head sealing pair. The first sealing ball head can slide along the length direction of the lower graphite dewaxing tube within the ball head sealing surface. A second sealing ball head is fixedly installed on the outer side of the other end of the upper graphite dewaxing tube. An adaptive pre-tightening mechanism is disposed at the upper end of the graphite box and forms a ball-head sealing pair with the second sealing ball head. The adaptive pre-tightening mechanism is used to enable the dewaxing tube on the graphite to swing around the center of the ball head and perform axial floating compensation.

[0007] Furthermore, a guide heat insulation sleeve is fixedly installed on the upper end of the graphite box. The guide heat insulation sleeve is located outside the dewaxing tube on the graphite and the adaptive pre-tightening mechanism, and is used to guide the adaptive pre-tightening mechanism and isolate the adaptive pre-tightening mechanism from direct radiative heat exchange with the high-temperature graphite tube.

[0008] Furthermore, a condensation guiding structure is provided inside the graphite dewaxing tube, which is used to collect and drain the liquid wax condensed on the inner wall of the graphite dewaxing tube.

[0009] Furthermore, a through hole is provided on the side wall of the graphite box, and the diameter of the through hole is larger than the diameter of the dewaxing tube on the graphite.

[0010] Furthermore, the adaptive pre-tightening mechanism includes a floating pressure plate, which is located above the graphite dewaxing tube. A ball-and-socket sealing surface corresponding to the second sealing ball head is provided in the middle of one side of the floating pressure plate, and the ball-and-socket sealing surface rotates and fits against the outside of the second sealing ball head to form a ball-and-socket sealing pair. A through hole penetrating the floating pressure plate is provided at the bottom end of the ball-and-socket sealing surface. A limiting component is provided between the guide insulation sleeve and the floating pressure plate, the limiting component being used to prevent the floating pressure plate from excessively pressing down on the second sealing ball head.

[0011] Furthermore, an adjusting plate is elastically connected to the side of the floating pressure plate away from the second sealing ball head via a disc spring. A threaded rod is slidably inserted into the middle part of the adjusting plate. One end of the threaded rod passes through the adjusting plate and is fixed to the inner wall of the guide heat insulation sleeve through a support plate. An adjusting nut is threadedly connected to the other end of the threaded rod.

[0012] Furthermore, ceramic heat-insulating washers are fixedly sleeved at all four ends of the floating pressure plate and the adjusting plate on the side closest to each other through positioning bosses, and the disc spring is fixed between the upper and lower ceramic heat-insulating washers.

[0013] Furthermore, the floating pressure plate, positioning boss, ceramic heat insulation gasket, and adjustment plate are all provided with corresponding guide rod sliding holes on their side walls. One end of the guide rod passes through multiple sliding holes and is fixed to the upper end of the graphite box.

[0014] Furthermore, the inner wall of the guide heat insulation sleeve is provided with multiple air guide grooves in the vertical direction, and the outer wall of the floating pressure plate and the inner wall of the guide heat insulation sleeve are slidably connected.

[0015] Furthermore, the limiting component includes a limiting block, which is annular and fixed to the inner wall of the guide heat insulation sleeve. When the disc spring reaches the pre-compression amount, the distance between the upper end face of the limiting block and the edge of the lower surface of the floating pressure plate is 0.3mm–0.5mm.

[0016] Furthermore, the condensation guiding structure includes an annular liquid collecting groove formed on the inner wall of the graphite dewaxing tube, a V-shaped groove formed at the bottom of the annular liquid collecting groove, a guiding pipe fixedly and inclinedly installed on the side wall of the graphite dewaxing tube and communicating with the V-shaped groove, and a spiral guiding groove formed on the inner wall of the graphite dewaxing tube, the lower end of the spiral guiding groove communicating with the annular liquid collecting groove.

[0017] Compared with the prior art, the beneficial effects of the present invention are: The two-section structure and the double ball head sealing pair are equivalent to a universal joint. Even if the furnace body and flange processing and welding errors cause the lower graphite dewaxing tube to be installed non-vertically, the upper graphite dewaxing tube can be automatically corrected by swinging the double ball head, and smoothly aligned with the graphite box, making installation convenient. During the heating and dewaxing process, the thermal expansion and elongation of the graphite tube is automatically absorbed by the axial floating of the ball head sealing pair and the elastic compression of the disc spring assembly. The sealing surface is always in contact with the surface and there will be no gaps, which prevents the paraffin vapor from leaking out or back-seeping and ensures the quality of dewaxing and sintering. When the graphite box needs to be disassembled, simply loosen the preload nut, remove the floating pressure plate and the dewaxing tube on the graphite, without touching the threaded connection part bonded at high temperature below, thus avoiding the graphite tube thread breaking, extending the component life and shortening maintenance time. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the existing structure's cross-section; Figure 2 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the upper end structure of the graphite dewaxing tube of the present invention; Figure 4 This is a schematic cross-sectional view of the adaptive pre-tightening mechanism and the guide heat insulation sleeve of the present invention; Figure 5 For the present invention Figure 2 Enlarged view of the structure of region A in the middle; Figure 6 This is a schematic cross-sectional view of the graphite dewaxing tube of the present invention; Figure 7 This is a schematic diagram showing the connection between the adaptive pre-tightening mechanism and the guide heat insulation sleeve of the present invention; Figure 8 This is a schematic diagram of the inner end structure of the guide heat insulation sleeve of the present invention; Figure 9 This is a schematic diagram of the adaptive pre-tightening mechanism of the present invention.

[0019] In the picture: 10. Furnace body; 11. Mounting flange; 12. Lower extraction pipe; 13. Carbon felt insulation cylinder; 14. Graphite box; 20. Lower graphite dewaxing tube; 201. Ball head sealing surface; 21. Upper graphite dewaxing tube; 211. First sealing ball head; 212. Second sealing ball head; 22. Limiting block; 30. Guide heat insulation sleeve; 301. Air guide groove; 40. Floating pressure plate; 41. Ball socket sealing surface; 411. Air hole; 42. Positioning boss; 43. Ceramic heat insulation washer; 44. Guide rod; 45. Disc spring; 46. Adjusting plate; 47. Support plate; 48. Threaded rod; 49. Adjusting nut; 50. Annular liquid collection tank; 51. V-shaped groove; 52. Guide pipe; 53. Spiral guide groove. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clear and complete, the embodiments of this invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of this invention, and are merely illustrative of the embodiments of this invention. They are not intended to limit the embodiments of this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Please see Figures 2 to 9 The present invention provides the following technical solution: a dewaxing tube structure for a sintering furnace, comprising: a graphite lower dewaxing tube 20, a lower extraction tube 12 provided on one side of the graphite lower dewaxing tube 20, the lower extraction tube 12 being fixed to the outer wall of the furnace body 10 via a mounting flange 11, one end of the graphite lower dewaxing tube 20 being threadedly connected to the outer wall of the mounting flange 11 and communicating with the lower extraction tube 12, the other end of the graphite lower dewaxing tube 20 passing through a carbon felt insulation cylinder 13, a ball-head sealing surface 201 for movable sealing with the graphite lower dewaxing tube 20 being provided on the inner side of the other end of the graphite lower dewaxing tube 20 near the port, and an upper graphite dewaxing tube 21 located above the graphite lower dewaxing tube 20. A through hole is provided on the side wall of the graphite box 14, and the diameter of the through hole is larger than the diameter of the graphite upper dewaxing tube 21. One end of the graphite upper dewaxing tube 21 slides through the graphite box 14 and is fixedly installed with a first sealing ball head 211 corresponding to the ball head sealing surface 201. The first sealing ball head 211 is inserted into the ball head sealing surface 201 and forms a ball head sealing pair. The first sealing ball head 211 can slide along the length direction of the graphite lower dewaxing tube 20 and swing within a small range within the ball head sealing surface 201. A second sealing ball head 212 is fixedly installed on the outer side of the other end of the graphite upper dewaxing tube 21. The second sealing ball head 212 is located above the graphite box 14.

[0022] An adaptive pre-tightening mechanism is set at the upper end of the graphite box 14 and forms a ball head sealing pair between the second sealing ball head 212. The adaptive pre-tightening mechanism enables the graphite dewaxing tube 21 to swing around the center of the ball head and perform axial floating compensation. The adaptive pre-tightening mechanism provides a constant axial elastic force to the graphite tube and absorbs the thermal elongation of the graphite tube.

[0023] Specifically, by connecting one end of the lower graphite dewaxing tube 20 to the mounting flange 11 via a threaded seal, one end of the upper graphite dewaxing tube 21 is passed through the through hole on the graphite box 14, and the first sealing ball head 211 is inserted into the ball head sealing surface 201 to form a ball head sealing pair. Then, the adaptive pre-tightening mechanism is installed at the upper end of the graphite box 14, and forms a ball head sealing pair with the second sealing ball head 212 at the upper end of the upper graphite dewaxing tube 21. The adaptive pre-tightening mechanism provides a constant axial elastic force to the graphite tube, absorbs the thermal elongation of the graphite tube, and the upper graphite dewaxing tube 21 can swing around the center of the ball head, making installation more convenient.

[0024] like Figure 2 - Figure 5 As shown, in some embodiments, the adaptive pre-tightening mechanism includes a floating pressure plate 40, which is made of isostatic graphite or silicon carbide. The floating pressure plate 40 is located above the dewaxing tube 21 on the graphite. A ball-and-socket sealing surface 41 corresponding to the second sealing ball head 212 is provided at the middle of one side of the floating pressure plate 40. The ball-and-socket sealing surface 41 rotates and fits against the outside of the second sealing ball head 212 to form a ball-and-socket sealing pair. A vent 411 penetrating the floating pressure plate 40 is provided at the bottom end of the ball-and-socket sealing surface 41. The second sealing ball head 212 can rotate within the ball-and-socket sealing surface 41 and communicate with the vent 411.

[0025] A limiting component is provided between the guide insulation sleeve 30 and the floating pressure plate 40. The limiting component is used to prevent the floating pressure plate 40 from excessively pressing down on the second sealing ball head 212. The side of the floating pressure plate 40 away from the second sealing ball head 212 is elastically connected to the adjusting plate 46 via a disc spring 45. The four ends of the floating pressure plate 40 and the adjusting plate 46 that are close to each other are all fixedly fitted with ceramic heat insulation washers 43 via positioning bosses 42. The disc spring 45 is fixed between the upper and lower ceramic heat insulation washers 43. The ceramic heat insulation washers 43 physically isolate the disc spring 45 from the floating pressure plate 40 (up to 400℃), maintaining the working temperature of the disc spring 45 ≤300℃. The adjusting plate 46 can move towards one side of the floating pressure plate 40 by squeezing the disc spring 45. The disc spring 45 transmits the thrust applied by the adjusting plate 46 to the floating pressure plate 40. The floating pressure plate 40 is tightly attached to the outer end of the second sealing ball head 212 through the ball-and-socket sealing surface 41, providing a downward pressure to the ball-and-socket sealing surface 41 that is always attached to the outer end of the second sealing ball head 212, ensuring the sealing effect between the ball-and-socket sealing surface 41 and the second sealing ball head 212. At the same time, after the graphite tube expands due to heat, it will push the floating pressure plate 40 to move upward by squeezing the disc spring 45, providing a constant axial elastic force to the graphite tube and absorbing the thermal elongation of the graphite tube.

[0026] The disc spring 45 is made of Inconel 718 or GH4169 high-temperature alloy disc spring, which still maintains ≥85% of its elastic modulus at 600℃. The ceramic heat insulation washer 43 is a silicon nitride (Si3N4) ceramic washer (3mm thick). The ceramic washer has concentric ring grooves on both sides, which form a labyrinthine heat insulation barrier with the contact surface of the disc spring 45, reducing the temperature transmitted to the adjusting nut 49 by more than 150℃.

[0027] A threaded rod 48 is slidably inserted into the middle part of the adjusting plate 46. One end of the threaded rod 48 passes through the adjusting plate 46 and is fixed to the inner wall of the guide heat insulation sleeve 30 through the support plate 47. The other end of the threaded rod 48 is threadedly connected to an adjusting nut 49. The pre-compression of the disc spring 45 is set to 75% of the working stroke (the working stroke of the disc spring 45 is 1.5mm ± 0.1mm, ensuring that when the graphite tube has the maximum thermal expansion (about 1.2mm / 600℃), the remaining elastic force is still higher than the minimum specific pressure required for sealing (≥0.5MPa).

[0028] The floating pressure plate 40, the positioning boss 42, the ceramic heat insulation washer 43, and the side wall of the adjusting plate 46 are all provided with corresponding guide rod 44 sliding holes. A heat-insulating silicon nitride ceramic sleeve is fixedly sleeved in the sliding hole on the adjusting plate 46. One end of the guide rod 44 passes through multiple sliding holes and is fixed to the upper end of the graphite box 14.

[0029] Specifically, during installation, tightening the adjusting nut 49 compresses the disc spring 45 to the preset position, the floating pressure plate 40 presses against the second sealing ball head 212, and the limiting block 22 does not touch the lower surface of the floating pressure plate 40. The initial sealing pressure meets the standard, and there is no risk of overload on the graphite tube. During heating and dewaxing (0→600℃), the graphite tube elongates axially, pushing the floating pressure plate 40 upward. The disc spring 45 is further compressed, and the ceramic heat insulation gasket 43 blocks the upward flow of heat. The sealing pressure remains basically constant, and there is no leakage. During constant temperature sintering, the thermal expansion is stable, the disc spring 45 remains compressed, and the limiting block 22 approaches but does not touch the lower surface of the floating pressure plate 40, ensuring long-term reliable sealing. During cooling, the graphite tube contracts, the disc spring 45 rebounds and releases stored energy, and the floating pressure plate 40 moves downward, always maintaining a close fit without gaps throughout the process.

[0030] like Figure 3 and Figure 4 As shown, in some embodiments, a guide heat insulation sleeve 30 is fixedly installed on the upper end of the graphite box 14. The guide heat insulation sleeve 30 is made of carbon-carbon composite material (C / C) or high-purity alumina ceramic. The guide heat insulation sleeve 30 is located outside the graphite dewaxing tube 21 and the adaptive pre-tightening mechanism. The guide heat insulation sleeve 30 is a thin-walled cylindrical shape, with its lower end fixed to the upper end of the graphite box 14 and its upper end extending to the middle of the disc spring 45. The inner wall is provided with longitudinal air guide grooves 301 (2mm wide × 1mm deep, 4 grooves evenly distributed) to balance the air pressure inside and outside the sleeve and avoid gas leakage during vacuum / atmosphere switching. The plug effect hinders floating. The guide heat insulation sleeve 30 is used to guide the adaptive pre-tightening mechanism and isolate the adaptive pre-tightening mechanism from the direct radiative heat exchange between the adaptive pre-tightening mechanism and the high-temperature graphite tube. The outer wall of the floating pressure plate 40 and the inner wall of the guide heat insulation sleeve 30 are slidably connected. More specifically, the guide heat insulation sleeve 30 provides radial guidance for the floating pressure plate 40 to prevent the floating pressure plate 40 from deflecting under the action of pre-tightening force, ensuring that the ball socket sealing surface 41 and the second sealing ball head 212 are always concentrically fitted. The guide heat insulation sleeve 30 also isolates the disc spring 45 from the direct radiative heat exchange between the high-temperature graphite tube and the disc spring 45.

[0031] like Figure 3 and Figure 4 As shown, in some embodiments, the limiting component includes a limiting block 22, which is in the shape of a hollow frustum and is fixed on the inner wall of the guide heat insulation sleeve 30. When the disc spring 45 is pressed down to the pre-compression amount, the floating pressure plate 40 reaches the maximum preset stroke. At this time, the distance between the upper end face of the limiting block 22 and the lower surface edge of the floating pressure plate 40 is 0.3mm–0.5mm, which limits the radial swing amplitude of the second sealing ball head 212 to within ±3°.

[0032] More specifically, graphite is a typical brittle material with high compressive strength but extremely poor bending and impact resistance. If the tightening torque of the adjusting nut 49 is too high during on-site assembly, or if the disc spring 45 is incorrectly selected, resulting in excessive preload, the enormous axial pressure will directly act on the ball head seal pair, easily causing the graphite ball head to crush, break, or undergo plastic deformation of the sealing surface, leading to irreversible seal failure. When the disc spring 45 is compressed to the pre-compression amount, a safety gap of 0.3mm–0.5mm is reserved between the upper end face of the limit block 22 and the lower edge of the floating pressure plate 40 at the preset maximum stroke. When the preload increases abnormally and the floating pressure plate 40 is excessively compressed beyond the preset maximum stroke, the lower edge of the floating pressure plate 40 will contact the upper end face of the limit block 22 first, forming a rigid mechanical stop. At this time, the excessive load is borne by the limit block 22, thereby protecting the fragile ball head seal pair from damage.

[0033] like Figure 3 and Figure 6As shown, in some embodiments, a condensation guiding structure is provided inside the graphite dewaxing tube 21. This condensation guiding structure is used to collect and drain the liquid wax condensed on the inner wall of the graphite dewaxing tube 21. The condensation guiding structure includes an annular collection trough 50 formed on the inner wall of the graphite dewaxing tube 21. A V-shaped groove 51 is formed at the bottom of the annular collection trough 50. The cross-section of the annular collection trough 50 and the V-shaped groove 51 is V-shaped, with a width of 4mm–6mm and a depth of 3mm–4mm. This serves as the terminal collection pool of the spiral guiding groove 53, temporarily... The system stores and collects liquid paraffin; the V-shaped bottom allows the liquid to naturally concentrate at the center line of the tank bottom, providing a stable liquid seal for the drainage micro-holes. A guide pipe 52, connected to the V-shaped groove 51, is fixedly and obliquely installed on the side wall of the graphite dewaxing tube 21. A collection box is installed at the lower end of the graphite box 14, and the oblique lower end of the guide pipe 52 is inserted into the collection box to collect the drained liquid wax. A spiral guide groove 53 is formed on the inner wall of the graphite dewaxing tube 21, and the lower end of the spiral guide groove 53 is connected to the annular liquid collection tank 50. The spiral guide groove 53 provides... Rectangular or trapezoidal cross-section, 3mm–4mm wide, 1.5mm–2mm deep, pitch: 40mm–60mm (corresponding to a helix angle of 3°–5°), ensuring that the condensate flows stably downward under the influence of gravity, rather than being re-entrained by the rising airflow. Rotation direction: consistent with the rotation direction of the main exhaust airflow inside the furnace (if it is a straight exhaust, then a right-handed rotation is used). Utilizing the tangential velocity of the airflow to assist the liquid film movement, it captures the condensate droplets that were originally randomly attached to the inner wall and guides them into the tank, forming a continuous liquid film; the spiral path extends the droplet... Residence time promotes the aggregation of small droplets into large droplets, reducing the risk of being entrained by airflow. More specifically, during the dewaxing process, when paraffin vapor rises inside the pipe, it is easy to condense and accumulate carbon at the lower temperature of the pipe opening or sealing gap. Long-term operation can block the channel or jam the ball head, resulting in "cannot be disassembled" or "poor sealing". By processing an annular liquid collection groove 50 on the inner side of the graphite dewaxing tube 21 and opening a spiral guide groove 53 leading to the main exhaust channel, the condensed droplets are discharged by gravity and airflow shear force, avoiding their accumulation on the sealing surface.

[0034] During installation, the lower graphite dewaxing tube 20 and the mounting flange 11 are first connected by threaded sealing. Due to machining and welding errors of the mounting flange 11, the lower graphite dewaxing tube 20 may have a verticality deviation of 2° to 4°. Then, the first sealing ball head 211 of the upper graphite dewaxing tube 21 is seated into the ball head sealing surface 201. With the help of the universal swing characteristics of the double ball head sealing pair, the upper graphite dewaxing tube 21 automatically corrects the tilt deviation, and the upper end is smoothly aligned with the through hole of the graphite box 14. Then, the floating pressure plate 40 is placed, the second sealing ball head 212 is seated into the ball socket sealing surface 41, the disc spring 45 and the adjusting plate 46 are installed, and the adjusting nut 49 is tightened to complete the installation. No repeated adjustments are required.

[0035] During the dewaxing process, the furnace temperature is raised to below 600℃. Paraffin vapor is discharged into the lower extraction pipe 12 through the upper graphite dewaxing pipe 21 and the lower graphite dewaxing pipe 20. During the heating process, the graphite pipes are heated and elongated. The upper graphite dewaxing pipe 21 floats upward along the ball head sealing pair. The disc spring 45 is compressed and absorbs the displacement. The two ball sealing pairs are always tightly fitted, and there is no leakage throughout the process.

[0036] When the graphite box 14 needs to be cleaned or disassembled, simply loosen the adjusting nut 49, remove the floating pressure plate 40 and the graphite dewaxing tube 21, and the graphite box 14 can be removed separately. There is no need to touch the threaded part that is bonded to the lower part of the extraction pipe 12, thus avoiding the graphite tube from breaking and greatly improving maintenance efficiency.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

Claims

1. A dewaxing tube structure for a sintering furnace, characterized in that, include: The graphite dewaxing tube (20) has one end threaded to the outer wall of the mounting flange (11) and the other end passes through the carbon felt insulation cylinder (13). A ball head sealing surface (201) is provided on its inner side for movable sealing with the graphite dewaxing tube (20). The upper graphite dewaxing tube (21) is located above the lower graphite dewaxing tube (20). One end of the upper graphite dewaxing tube (21) slides through the graphite box (14) and is fixedly installed with a first sealing ball head (211) corresponding to the ball head sealing surface (201). The first sealing ball head (211) is inserted into the ball head sealing surface (201) and forms a ball head sealing pair. The first sealing ball head (211) can slide along the length direction of the lower graphite dewaxing tube (20) within the ball head sealing surface (201). A second sealing ball head (212) is fixedly installed on the outer side of the other end of the upper graphite dewaxing tube (21). An adaptive pre-tightening mechanism is provided at the upper end of the graphite box (14) and forms a ball head sealing pair with the second sealing ball head (212). The adaptive pre-tightening mechanism is used to enable the graphite dewaxing tube (21) to swing around the center of the ball head and perform axial floating compensation.

2. The dewaxing tube structure of the sintering furnace according to claim 1, characterized in that: A guide heat insulation sleeve (30) is fixedly installed on the upper end of the graphite box (14). The guide heat insulation sleeve (30) is located outside the graphite dewaxing tube (21) and the adaptive pre-tightening mechanism. It is used to guide the adaptive pre-tightening mechanism and isolate the adaptive pre-tightening mechanism from the direct radiative heat exchange between the adaptive pre-tightening mechanism and the high-temperature graphite tube.

3. The dewaxing tube structure of the sintering furnace according to claim 1, characterized in that: The graphite dewaxing tube (21) is provided with a condensation guiding structure, which is used to collect and drain the liquid wax condensed on the inner wall of the graphite dewaxing tube (21).

4. The dewaxing tube structure of the sintering furnace according to claim 1, characterized in that: The graphite box (14) has a through hole on its side wall, and the diameter of the through hole is larger than the diameter of the graphite dewaxing tube (21).

5. The dewaxing tube structure of the sintering furnace according to claim 2, characterized in that: The adaptive pre-tightening mechanism includes a floating pressure plate (40), which is located above the graphite dewaxing tube (21). A ball-and-socket sealing surface (41) corresponding to the second sealing ball head (212) is provided at the middle of one side of the floating pressure plate (40). The ball-and-socket sealing surface (41) rotates and fits against the outside of the second sealing ball head (212) to form a ball-and-socket sealing pair. A vent (411) penetrating the floating pressure plate (40) is provided at the bottom end of the ball-and-socket sealing surface (41). A limiting component is provided between the guide insulation sleeve (30) and the floating pressure plate (40), the limiting component being used to prevent the floating pressure plate (40) from excessively pressing down on the second sealing ball head (212).

6. The dewaxing tube structure of the sintering furnace according to claim 5, characterized in that: The floating pressure plate (40) is elastically connected to an adjusting plate (46) on the side away from the second sealing ball head (212) via a disc spring (45). A threaded rod (48) is slidably inserted into the middle part of the adjusting plate (46). One end of the threaded rod (48) passes through the adjusting plate (46) and is fixed to the inner wall of the guide heat insulation sleeve (30) via a support plate (47). The other end of the threaded rod (48) is threadedly connected to an adjusting nut (49).

7. The dewaxing tube structure of the sintering furnace according to claim 6, characterized in that: The floating pressure plate (40) and the adjusting plate (46) are respectively connected to ceramic heat insulation washers (43) by positioning bosses (42) at their four ends. The disc spring (45) is fixed between the upper and lower ceramic heat insulation washers (43).

8. The dewaxing tube structure for a sintering furnace according to claim 7, characterized in that: The floating pressure plate (40), positioning boss (42), ceramic heat insulation gasket (43) and adjusting plate (46) are all provided with corresponding guide rod (44) sliding holes on their side walls. One end of the guide rod (44) passes through multiple sliding holes and is fixed to the upper end of the graphite box (14).

9. The dewaxing tube structure of the sintering furnace according to claim 2, characterized in that: The inner wall of the guide heat insulation sleeve (30) is provided with multiple air guide grooves (301) in the vertical direction, and the outer wall of the floating pressure plate (40) and the inner wall of the guide heat insulation sleeve (30) are slidably connected.

10. The dewaxing tube structure of the sintering furnace according to claim 6, characterized in that: The limiting component includes a limiting block (22), which is annular and fixed on the inner wall of the guide heat insulation sleeve (30). When the disc spring (45) reaches the pre-compression amount, the distance between the upper end face of the limiting block (22) and the lower surface edge of the floating pressure plate (40) is 0.3mm–0.5mm.

11. The dewaxing tube structure of the sintering furnace according to claim 3, characterized in that: The condensation guiding structure includes an annular liquid collection groove (50) formed on the inner wall of the graphite dewaxing tube (21), a V-shaped groove (51) formed at the bottom of the annular liquid collection groove (50), a guide pipe (52) connected to the V-shaped groove (51) fixedly and obliquely installed on the side wall of the graphite dewaxing tube (21), and a spiral guide groove (53) formed on the inner wall of the graphite dewaxing tube (21), the lower end of the spiral guide groove (53) being connected to the annular liquid collection groove (50).

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