A bell type sintering furnace insulation bucket capable of improving temperature field equalization performance

Abstract

This invention relates to the field of sintering furnace insulation technology, specifically providing a bell-shaped sintering furnace insulation barrel that improves temperature field uniformity. The barrel includes a base, an inner cylinder, an insulation layer, and an outer cylinder. The inner cylinder comprises an inverted body and a bottom. An upper cover plate is provided at the upper end of the insulation layer, and a top cover plate is provided at the upper end of the outer cylinder. A compression gap exists between the upper and top cover plates. The upper cover plate includes a guide pin and a compression spring assembly. The insulation layer comprises side carbon paper and carbon felt layers wrapped around the outer wall of the cylinder body and a top carbon paper and carbon felt layer wrapped around the outer end face of the bottom of the cylinder. The top carbon paper and carbon felt layer is formed by folding upwards from the folded layers in the side carbon paper and carbon felt layers. A cylindrical thickened insulation body is laid between adjacent top carbon paper and carbon felt layers. When the insulation barrel expands due to high temperature and pressure, the compression spring assembly provides compression to ensure temperature uniformity in the furnace and improves the insulation performance of the sintering furnace insulation barrel.

Description

Technical Field

[0001] This invention relates to the field of sintering furnace insulation technology, and in particular to a bell-shaped sintering furnace insulation barrel that can improve the temperature field uniformity performance. Background Technology

[0002] A sintering furnace is a heat treatment furnace that provides a specific temperature and pressure environment for materials, increasing their sintering density and improving their mechanical properties. By heating and sintering metal, ceramic, or some refractory metal intermediate compound powders in a vacuum and protective atmosphere within the sintering furnace, dense materials with certain density and mechanical properties can be obtained. Sintering furnaces mainly include vacuum pressure sintering furnaces and electric discharge plasma sintering furnaces. Vacuum pressure sintering furnaces combine vacuum, high pressure, and high temperature sintering, and are widely used in the sintering and forming of various anti-oxidation materials in powder metallurgy and vacuum diffusion welding fields. Vacuum sintering furnaces typically have an outer shell and an inner insulation chamber.

[0003] Currently, the insulation containers for vertical sintering furnaces and hot isostatic pressing sintering furnaces are similar to those for horizontal sintering furnaces, consisting of a lower cover, a cylinder, and an upper cover. This type of insulation container is simple to manufacture and easy to install, but its insulation effect is poor, especially the uneven temperature field, with the bottom being cold and the top hot. As the temperature and pressure gradually increase, especially for furnaces with larger volumes, the uniformity of temperature inside the insulation container becomes an important indicator of the furnace's performance. If the insulation container has poor temperature uniformity, it is very easy for uneven temperature and large temperature differences between the inside and outside to occur during the production process, resulting in a decrease in product qualification rate and even damage to raw materials, causing serious economic losses to the user.

[0004] Therefore, how to design a sintering furnace insulation tank that can ensure temperature uniformity in the sintering zone and reduce the temperature difference between the bottom and top is an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a bell-shaped sintering furnace insulation barrel that can improve temperature field uniformity. This design utilizes an inverted inner cylinder, a central compression component, and an insulation layer to enhance the uniformity of temperature differences within the furnace and improve insulation performance. This avoids large internal and external temperature differences and large vertical temperature differences, thereby increasing product qualification rate and reducing raw material loss.

[0006] To achieve the above objectives, the present invention proposes the following technical solution: a bell-shaped sintering furnace insulation barrel that can improve the temperature field uniformity performance, comprising a base and an inner cylinder and an outer cylinder sequentially fitted on the upper end of the base from the inside out. The inner cylinder includes a cylinder body and a cylinder bottom, and the inner cylinder is inverted so that the cylinder bottom is located entirely at the upper end of the cylinder body. An insulation layer is laid between the inner cylinder and the outer cylinder, and an upper cover plate is provided on the upper end of the insulation layer. A top cover plate is provided on the upper end of the outer cylinder above the upper cover plate, and a compression gap is included between the upper cover plate and the top cover plate. The upper cover plate includes a side guide member and a middle compression member extending upward to the top of the top cover plate. When the insulation barrel expands and contracts due to high temperature and high pressure, the inner cylinder, the insulation layer, and the upper cover plate are guided by the guide member to move up and down inside the outer cylinder and the compression is provided by the middle compression member.

[0007] Preferably, the inner cylinder and the outer cylinder are connected to the inner circumferential surface and the outer circumferential surface of the base, respectively; there is a ventilation gap between the insulation layer and the base, and high-pressure air holes are evenly distributed along the circumferential direction on the inner cylinder wall at the ventilation gap.

[0008] Preferably, the top cover plate has a compression through hole in the middle and a guide through hole located outside the compression through hole; the middle compression member includes a plurality of compression spring assemblies connected to the upper end of the top cover plate and extending upward from the compression through hole to the top of the top cover plate; the side guide member includes a guide pin connected to the upper end of the top cover plate and extending upward from the guide through hole to the top of the top cover plate, the guide pin being slidably connected to the top cover plate.

[0009] Preferably, the outer end face of the top cover plate is provided with multiple fastening strips that are pressed against the outer circumference of the insulation layer; the height of the fastening strips is lower than the height of the insulation layer and extends downward from the top cover plate to near the lower end face of the insulation layer.

[0010] Preferably, the top cover plate is provided with a side through hole located between the guide through hole and the outer end face of the top cover plate, and the side through hole is staggered from the guide through hole; a thermocouple is provided between the insulation layer and the outer cylinder, the upper end of the thermocouple passes through the side through hole and is connected to the upper end of the top cover plate, and the lower end of the thermocouple extends from the base.

[0011] Preferably, the top cover plate is provided with a bumper plate extending to the outside of the top cover plate along the circumferential direction; the guide through hole and the compression through hole are further provided with a mounting lug on the top cover plate; the mounting lug, thermocouple, guide pin and bumper plate are staggered.

[0012] Preferably, the insulation layer is a multi-layer carbon paper and carbon felt layer structure wrapped layer by layer on the outer wall of the inner cylinder. After each layer of carbon paper and carbon felt is wrapped, the carbon paper and carbon felt layer is tightly wrapped before wrapping the next layer of carbon paper and carbon felt layer. The thickness of each layer of carbon paper and carbon felt layer is the same or different and is set according to the internal and external temperature difference requirements. The interface positions of each layer of carbon paper and carbon felt layer are staggered.

[0013] Preferably, the insulation layer includes a side carbon paper and carbon felt layer wrapped around the outer wall of the cylinder and a top carbon paper and carbon felt layer wrapped around the outer end face of the bottom of the cylinder. The overall thickness of the top carbon paper and carbon felt layer is greater than the overall thickness of the side carbon paper and carbon felt layer, and part of the top carbon paper and carbon felt layer is formed by folding the side carbon paper and carbon felt layer upwards.

[0014] Preferably, during the laying of each layer of side carbon paper and carbon felt, a folded layer extending to the top of the cylinder is reserved. The folded layer is cut into a fan-shaped structure that matches the local shape of the cylinder bottom and folded over to the middle of the cylinder bottom. When each layer of side carbon paper and carbon felt is laid, multiple folded layers cover the top surface of the cylinder bottom.

[0015] Preferably, after each layer of side carbon paper and carbon felt and each layer of top carbon paper and carbon felt are laid, a cylindrical thickened insulation layer matching the overall shape of the cylinder bottom is laid on the upper surface of the top carbon paper and carbon felt layer of the current layer; then the next layer of top carbon paper and carbon felt and side carbon paper and carbon felt are laid; after all the top carbon paper and carbon felt layers and side carbon paper and carbon felt layers are laid, a top cover plate is installed on the upper surface of the top carbon paper and carbon felt layer.

[0016] The beneficial effects of this invention are:

[0017] 1. In this design, a compression spring assembly is installed on the upper cover plate. The compression spring assembly itself has a downward pre-compression force, which can provide flexible pressure to the insulation barrel to ensure that the insulation barrel will not move when high-pressure gas is introduced. At the same time, since the spring can be further compressed, as high-pressure gas is continuously introduced into the furnace and the temperature and pressure inside the furnace gradually rise, the insulation barrel will stretch when it expands thermally and apply upward compression force to the compression spring assembly, increasing the amount of spring compression without damaging the insulation barrel. The compression spring assembly can further increase the compression force on the insulation barrel through the two opposing forces of downward pre-compression force and upward compression force, thereby ensuring that the sintering furnace insulation barrel always remains in a stable position and will not move, ensuring a uniform temperature inside the furnace.

[0018] 2. The insulation layer of the sintering furnace insulation barrel in this invention includes a side carbon paper and carbon felt layer wrapped around the outer wall of the barrel body and a top carbon paper and carbon felt layer wrapped around the outer end face of the bottom of the barrel. The top carbon paper and carbon felt layer is formed by folding the folded layer in the side carbon paper and carbon felt layer upward. The folded layer is formed by reserving an extended section upward during the laying process of the side carbon paper and carbon felt layer, so that the top carbon paper and carbon felt layer and the side carbon paper and carbon felt layer are connected as an integral structure, which can ensure the insulation performance of the connection between the barrel body and the bottom of the inverted inner barrel and the overall insulation performance. At the same time, when the high-pressure gas flows continuously from bottom to top, the heat at the top is lost faster. A cylindrical thickened insulation body matching the overall shape of the bottom of the barrel is laid between the adjacent top carbon paper and carbon felt layers. The overall thickness of the top carbon paper and carbon felt layer is greater than the overall thickness of the side carbon paper and carbon felt layer, which can avoid the loss of heat at the top, reduce the temperature difference between the top and bottom of the furnace, improve the temperature uniformity in the furnace, and improve the insulation performance of the sintering furnace insulation barrel. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the sintering furnace insulation barrel provided in an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 Top view.

[0021] Figure 3 yes Figure 2 A cross-sectional view along the AA direction.

[0022] Figure 4 yes Figure 1 Front view (outer cylinder not shown).

[0023] Figure 5 A schematic diagram of the overall structure of the insulation layer provided in this embodiment of the invention.

[0024] Figure 6 This is a schematic diagram of the side carbon paper and carbon felt layer laying structure provided in an embodiment of the present invention.

[0025] Reference numerals: 1. Base; 2. Inner cylinder; 3. Outer cylinder; 4. Cylinder body; 5. Cylinder bottom; 6. Insulation layer; 7. Top cover plate; 8. Compression gap; 9. Ventilation gap; 10. High-pressure vent; 11. Graphite retaining ring; 12. Compression through hole; 13. Guide through hole; 14. Guide pin; 15. Fastening strip; 16. Side through hole; 17. Thermocouple; 18. Anti-collision plate; 19. Mounting lug; 20. Pressure plate; 21. Spring seat; 22. Compression spring; 23. Spring guide sleeve 24, middle compression spring assembly 25, side compression spring assembly 26, fixing part 27, protective part 28, anti-collision straight surface 29, avoidance inclined surface 30, support ear 31, lifting ear 32, weight reduction through hole 33, mounting platform 34, lower through hole 35, straight surface connection part 36, arc-shaped clamping part 37, side carbon paper and carbon felt layer 38, folded layer 39, top carbon paper and carbon felt layer 40, thickened insulation body 41. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1-6 The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof.

[0027] A bell-shaped sintering furnace insulation barrel that can improve temperature field uniformity, such as Figure 1 and 3 As shown, the device includes a base 1, an inner cylinder 2, an insulation layer 6, and an outer cylinder 3. The inner cylinder 2 and the outer cylinder 3 are sequentially fitted onto the upper end of the base 1 from the inside to the outside. The insulation layer 6 is laid between the inner cylinder 2 and the outer cylinder 3. The inner cylinder 2 includes a cylinder body 4 and a cylinder bottom 5. The inner cylinder 2 has an inverted bell-shaped structure, so that the cylinder bottom 5 is located on the upper end of the cylinder body 4. The upper end of the insulation layer 6 is provided with an upper cover plate 7, and the upper end of the outer cylinder 3 is provided with a top cover plate 8. The top cover plate 8 is located above the upper cover plate 7. There is a compression gap 9 between the upper cover plate 7 and the top cover plate 8, which provides expansion and contraction space for the vertical movement of the inner cylinder 2.

[0028] like Figure 1-3As shown, the upper cover plate 7 includes a side guide extending upward to the top cover plate 8 and a central compression member. The top cover plate 8 has a compression through hole 13 in the center and a guide through hole 14 located outside the compression through hole 13. The central compression member includes a plurality of compression spring assemblies connected to the upper end of the upper cover plate 7 and extending upward from the compression through hole 13 to the top cover plate 8. The side guide includes a guide pin 15 connected to the upper end of the upper cover plate 7 and extending upward from the guide through hole 14 to the top cover plate 8. The guide pin 15 is slidably connected to the top cover plate 8. When the insulation barrel expands and contracts due to high temperature and high pressure, the inner cylinder 2, insulation layer 6, and upper cover plate 7 move up and down in the outer cylinder 3 guided by guide pin 15, and the compression is provided by the middle compression component; the compression spring assembly has a downward pre-compression force. When the insulation barrel is in a high temperature and high pressure state, the inner cylinder 2, insulation layer 6, and upper cover plate 7 move upward in the outer cylinder 3 and apply an upward compression force to the compression spring assembly. The downward pre-compression force and the upward compression force of the compression spring assembly keep the sintering furnace insulation barrel stable in a high temperature and high pressure state.

[0029] like Figure 1-3 As shown, the compression spring assembly includes a spring seat 22 fixedly connected to the middle of the upper cover plate 7 and a compression spring 23 disposed on the spring seat 22. The upper end of the spring seat 22 includes a spring guide sleeve 24 sleeved inside the compression spring 23. The compression spring assembly includes a central compression spring assembly 25 located at the center of the upper cover plate 7 and multiple sets of side compression spring assemblies 26 evenly distributed circumferentially around the central compression spring assembly 25. In this embodiment, a total of six side compression spring assemblies 26 are evenly distributed circumferentially around the central compression spring assembly 25. The downward pre-compression force of the compression spring assembly is provided by the compression plate at the upper end of the spring guide sleeve 24 (the compression plate is not shown in the figure). The inner diameter of the compression through hole 13 is 0.3-0.6 times the inner diameter of the top cover plate 8. At the same time, the compression area and compression force of the compression spring assembly on the inner cylinder can be increased by one central compression spring assembly 25 and six side compression spring assemblies 26, further preventing the insulation bucket from moving during use.

[0030] like Figure 1-3 As shown, the top cover plate 8 is provided with a side through hole 17 located between the guide through hole 14 and the outer end face of the top cover plate 8, and the side through hole 17 is staggered from the guide through hole 14; a thermocouple 18 is provided between the insulation layer 6 and the outer cylinder 3, and the upper end of the thermocouple 18 passes through the side through hole 17 and is connected to the upper end of the top cover plate 8 through a pressure plate 21; the pressure plate 21 includes a side straight connecting part 36 connected to the top cover plate 8 and a central arc-shaped clamping part 37 that is pressed against the thermocouple 18, and the arc of the arc-shaped clamping part 37 is matched with the outer diameter of the thermocouple 18 to press the thermocouple 18 and prevent the thermocouple 18 from moving randomly during use; as Figure 4 As shown, a lower through hole 35 is provided on the outside of the graphite retaining ring 12 on the base 1, and the lower end of the thermocouple 18 passes through the lower through hole 35 and extends downward from the base 1.

[0031] like Figure 1 , 2 As shown, the top cover plate 8 is provided with a plurality of anti-collision plates 19 extending outward from the outer side of the top cover plate 8 along the circumferential direction. In this embodiment, a total of six evenly distributed anti-collision plates 19 are included. The anti-collision plates 19 are made of copper. Each anti-collision plate 19 includes a fixing part 27 connected to the top cover plate 8 and a protective part 28 extending 1-4mm outward from the outer side of the top cover plate 8. The fixing part 27 is connected to the top cover plate 8 by bolts, and the protective part 28 preferably extends 2mm outward from the outer side of the top cover plate 8. The protective part 28 includes an anti-collision straight surface 29 disposed away from the outer end face of the top cover plate 8 and a surface connected to the anti-collision straight surface. The avoidance inclined surface 30 between the surface 29 and the fixing part 27 is inclined from the end of the anti-collision straight surface 29 toward the side away from the anti-collision straight surface 29. Since the sintering furnace insulation barrel is prone to collision with the inner wall of the furnace shell when it is loaded and unloaded, there is a risk of damage to the furnace shell. By reducing the contact area between the anti-collision plate 19 and the inner wall of the furnace shell, the avoidance inclined surface 30 can ensure that the sintering furnace insulation barrel contacts the inner wall of the furnace shell through the anti-collision straight surface 29 of the copper structure and avoid scratching and wear on the furnace shell, thereby improving the service life of the furnace shell.

[0032] The guide through hole 14 and the compression through hole 13 also include a mounting lug 20 provided on the top cover plate 8. The mounting lug 20, thermocouple 18, guide pin 15 and anti-collision plate 19 are staggered to avoid interference. Figure 2 As shown, the mounting lug 20 includes a support lug 31 fixed to the top cover plate 8 and a lifting lug 32 fixed to the upper end of the support lug 31. The lifting lug 32 includes a weight-reducing through hole 33. By installing the mounting lug 20, the sintering furnace insulation barrel can be easily lifted, while the weight of the mounting lug 20 can be reduced, saving materials. In this embodiment, there are a total of three mounting lugs 20 set at different angles, so that the sintering furnace insulation barrel can be accurately positioned when lifted into the furnace shell by a special lifting tool, avoiding incorrect placement.

[0033] like Figure 3 and Figure 4 As shown, the inner cylinder 2 and the outer cylinder 3 are respectively connected to the inner and outer circumferential surfaces of the base 1. Specifically, the lower end of the inner cylinder 2 is connected to the inner circumferential surface of the base by bolts. The lower part of the outer circumferential surface of the base 1 protrudes outward to form a mounting platform 34. The lower part of the outer cylinder 3 is welded to the mounting platform 34. The inner cylinder 2 is made of graphite or CFC, and the outer cylinder 3 is made of high-temperature resistant stainless steel. There is a ventilation gap 10 between the insulation layer 6 and the base 1. Multiple high-pressure air holes 11 are evenly distributed along the circumference on the cylinder wall of the inner cylinder 2 at the ventilation gap 10. The high-pressure gas 11 enters the insulation barrel through the multiple high-pressure air holes 11 at the ventilation gap 10. A graphite retaining ring 12 is provided on the upper surface of the base 1 below the high-pressure air holes 11 on the outer side of the inner cylinder 2.

[0034] The insulation layer 6 is a multi-layer carbon paper and carbon felt structure wrapped layer by layer on the outer wall of the inner cylinder 2. After each layer of carbon paper and carbon felt is wrapped, the carbon paper and carbon felt layer is tightly wrapped with fine carbon rope or carbon wire before wrapping the next layer of carbon paper and carbon felt. The thickness of each layer of carbon paper and carbon felt may be the same or different and is set according to the internal and external temperature difference requirements. The interface positions of each layer of carbon paper and carbon felt are staggered. The insulation layer 6 includes a side carbon paper and carbon felt layer 38 wrapped on the outer wall of the cylinder body 4 and a top carbon paper and carbon felt layer 40 wrapped on the outer end face of the cylinder bottom 5. Since the inner cylinder 2 is an inverted structure, the outer end face of the cylinder bottom 5 is the bottom end face of the cylinder bottom 5 facing the upper cover plate 7.

[0035] like Figure 5 , 6 As shown, a portion of the top carbon paper and carbon felt layer 40 is formed by folding the side carbon paper and carbon felt layer 38 upwards, and another portion of the top carbon paper and carbon felt layer 40 is formed by a cylindrical thickened insulation body 41 that matches the overall shape of the bottom of the cylinder 5 and is laid between adjacent top carbon paper and carbon felt layers 40. Therefore, the overall thickness of the top carbon paper and carbon felt layer 40 is greater than the overall thickness of the side carbon paper and carbon felt layer 38, which can prevent the heat in the upper part of the furnace from dissipating too quickly and reduce the temperature difference in the furnace.

[0036] The folded layer 39 is formed by an extended section reserved upwards during the laying process of the side carbon paper and carbon felt layer 38. The folded layer 39 is a fan-shaped structure that matches the local shape of the bottom of the cylinder 5, such as... Figure 5 As shown, during the laying of each side carbon paper and carbon felt layer 38, a folded layer 39 extending above the bottom of the cylinder 5 is reserved. That is, the part of the top carbon paper and carbon felt layer 40 formed by the folded layer 39 is an integral structure connected to the side carbon paper and carbon felt layer 38, which can further ensure the heat preservation effect. The folded layer 39 is a fan-shaped structure that matches the local shape of the bottom of the cylinder 5. That is, the folded layer 39 is cut into a fan-shaped structure that matches the local shape of the bottom of the cylinder 5. The bottom of the cylinder 5 is circular as a whole, while the extended section reserved in the side carbon paper and carbon felt layer 38 is usually not connected to the bottom of the cylinder 5. The overall shape is a circle. Therefore, the extended section reserved in the side carbon paper and carbon felt layer 38 is first cut into a fan-shaped structure that matches the local shape of the bottom of the cylinder 5. Then, the folded layer 39 is folded towards the middle of the bottom of the cylinder 5. During the laying of each side carbon paper and carbon felt layer 38, the folded layer 39 is folded towards the middle multiple times. When each side carbon paper and carbon felt layer 38 is laid, the multiple folded layers 39 reserved during the laying of each side carbon paper and carbon felt layer 38 will cover the upper surface of the bottom of the cylinder 5 and form a top carbon paper and carbon felt layer 40.

[0037] like Figure 6As shown, after each layer of side carbon paper and carbon felt 38 and each layer of top carbon paper and carbon felt 40 are laid, a cylindrical thickened insulation layer 41 matching the overall shape of the bottom of the cylinder 5 is laid on the upper surface of the top carbon paper and carbon felt layer 40 of the current layer; then the next layer of top carbon paper and carbon felt layer 40 and side carbon paper and carbon felt layer 38 are laid; after all the top carbon paper and carbon felt layers 40 and side carbon paper and carbon felt layers 38 are laid, a top cover plate 7 is installed on the upper surface of the top carbon paper and carbon felt layer 40.

[0038] Multiple fastening strips 16 are provided on the outer end face of the top cover plate 7, which are pressed against the outer circumference of the side carbon paper and carbon felt layer 38 in the insulation layer 6. The fastening strips 16 are made of high-temperature resistant stainless steel. The lower end face of the side carbon paper and carbon felt layer 38 is as follows: Figure 4 As shown at point N, the lower end face of the fastening strip 16 is as follows Figure 4 As shown at point M, the height of the fastening strip 16 is lower than the height of the side carbon paper and carbon felt layer 38, and the fastening strip 16 extends downward from the upper cover plate 7 to near the lower end face of the side carbon paper and carbon felt layer 38, which can tighten the insulation layer 6 to improve the insulation effect without affecting the filling of high-pressure gas.

[0039] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0040] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A bell-shaped heat-insulating barrel for a sintering furnace that can improve temperature field uniformity, characterized in that, The device includes a base (1) and an inner cylinder (2) and an outer cylinder (3) that are sequentially fitted on the upper end of the base (1) from the inside to the outside. The inner cylinder (2) includes a cylinder body (4) and a cylinder bottom (5), and the inner cylinder (2) is inverted so that the cylinder bottom (5) is located on the upper end of the cylinder body (4). An insulation layer (6) is laid between the inner cylinder (2) and the outer cylinder (3). An upper cover plate (7) is provided on the upper end of the insulation layer (6). A top cover plate (8) is provided on the upper end of the outer cylinder (3) above the upper cover plate (7). A compression gap (9) is included between the upper cover plate (7) and the top cover plate (8). The upper cover plate (7) includes a side guide and a middle compression member that extend upward to the top cover plate (8). When the insulation barrel expands and contracts due to high temperature and high pressure, the inner cylinder (2), the insulation layer (6) and the upper cover plate (7) are guided by the guide to move up and down in the outer cylinder (3) and the compression is provided by the middle compression member. The inner cylinder (2) and the outer cylinder (3) are respectively connected to the inner circumferential surface and the outer circumferential surface of the base (1); the heat insulation layer (6) and the base (1) include a ventilation gap (10), and the inner cylinder (2) has high-pressure air holes (11) evenly distributed along the circumferential direction at the ventilation gap (10). The top cover plate (8) has a compression through hole (13) in the middle and a guide through hole (14) located outside the compression through hole (13); the middle compression member includes a plurality of compression spring assemblies connected to the upper end of the top cover plate (7) and extending upward from the compression through hole (13) to the top of the top cover plate (8); the side guide member includes a guide pin (15) connected to the upper end of the top cover plate (7) and extending upward from the guide through hole (14) to the top of the top cover plate (8), and the guide pin (15) is slidably connected to the top cover plate (8); The insulation layer (6) is a multi-layer carbon paper and carbon felt layer structure wrapped layer by layer on the outer wall of the inner cylinder (2). After each layer of carbon paper and carbon felt is wrapped, the carbon paper and carbon felt layer is tightly wrapped before wrapping the next layer of carbon paper and carbon felt layer. The thickness of each layer of carbon paper and carbon felt layer is the same or different and is set according to the internal and external temperature difference requirements. The interface positions of each layer of carbon paper and carbon felt layer are staggered. The insulation layer (6) includes a side carbon paper and carbon felt layer (38) wrapped around the outer wall of the cylinder body (4) and a top carbon paper and carbon felt layer (40) wrapped around the outer end face of the bottom of the cylinder (5). The overall thickness of the top carbon paper and carbon felt layer (40) is greater than the overall thickness of the side carbon paper and carbon felt layer (38). The top carbon paper and carbon felt layer (40) is formed by folding the side carbon paper and carbon felt layer (38) upwards. During the laying of each side carbon paper and carbon felt layer (38), a folded layer (39) extending to the top of the bottom of the cylinder (5) is reserved. The folded layer (39) is cut into a fan-shaped structure that matches the local shape of the bottom of the cylinder (5) and the folded layer (39) is folded onto the upper surface of the bottom of the cylinder (5) to the middle of the bottom of the cylinder (5). When each side carbon paper and carbon felt layer (38) is laid, multiple folded layers (39) cover the upper surface of the bottom of the cylinder (5). After each layer of side carbon paper and carbon felt (38) and each layer of top carbon paper and carbon felt (40) are laid, a cylindrical thickened insulation layer (6) matching the overall shape of the bottom of the cylinder (5) is laid on the upper surface of the top carbon paper and carbon felt layer (40) of the current layer; then the next layer of top carbon paper and carbon felt layer (40) and side carbon paper and carbon felt layer (38) are laid; after all the top carbon paper and carbon felt layers (40) and side carbon paper and carbon felt layers (38) are laid, a top cover plate (7) is set on the upper surface of the top carbon paper and carbon felt layer (40).

2. The bell-shaped sintering furnace insulation barrel with improved temperature field uniformity performance according to claim 1, characterized in that, The outer end face of the upper cover plate (7) is provided with a plurality of fastening strips (16) that are pressed against the outer periphery of the insulation layer (6); the height of the fastening strips (16) is lower than the height of the insulation layer (6) and extends downward from the upper cover plate (7) to the lower end face of the insulation layer (6).

3. The bell-shaped sintering furnace insulation barrel with improved temperature field uniformity performance according to claim 2, characterized in that, The top cover plate (8) is provided with a side through hole (17) located between the guide through hole (14) and the outer end face of the top cover plate (8). The side through hole (17) and the guide through hole (14) are staggered. A thermocouple (18) is provided between the insulation layer (6) and the outer cylinder (3). The upper end of the thermocouple (18) passes through the side through hole (17) and is connected to the upper end of the top cover plate (8). The lower end of the thermocouple (18) extends from the base (1).

4. The bell-shaped sintering furnace insulation barrel with improved temperature field uniformity performance according to claim 3, characterized in that, The top cover plate (8) is provided with a circumferential anti-collision plate (19) extending to the outside of the top cover plate (8); between the guide through hole (14) and the compression through hole (13), there is also a mounting lug (20) provided on the top cover plate (8); the mounting lug (20), thermocouple (18), guide pin (15) and anti-collision plate (19) are staggered.

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