A heat shield assembly and a vacuum furnace
Patent Information
- Application Number
- CN202522099722.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-28
- Publication Date
- 2026-09-08
- Estimated Expiration
- 2035-09-28
AI Technical Summary
现有技术中的隔热屏组件采用单一的碳毡或石墨毡构成，在碳材料加工(如石墨化)过程中，暴露于富含稠环芳烃、沥青质等高粘性焦油蒸汽的环境，这些蒸汽会渗透、浸润、吸附在毡体的高比表面积纤维和孔隙中，从而造成以下问题：1.孔隙堵塞与硬化：焦油冷凝后堵塞毡体的大量微孔和间隙，显著降低材料孔隙率，破坏其原本优异的绝热性能(气体对流传热虽在真空下弱化，但固相传热路径因焦油“粘接”纤维而显著增强)，2.纤维粘接与脆化：焦油作为粘性介质，将原本松散、可滑移的纤维粘接固化，导致毡体硬化、脆化，失去压缩回弹性，这不仅使保温性能急剧下降(导热系数上升)，更易在热应力下开裂、剥落，大幅缩短寿命，增加能耗和停机维护频率
[0015] The first ceramic fiber layer of this application, serving as the first line of defense closest to the furnace shell, provides excellent structural rigidity, compressive strength, and resistance to airflow erosion. The alumina matrix of the first ceramic fiber layer is inert to tar, effectively blocking and dispersing most of the initial tar vapor flow, preventing its direct and substantial backflow into the inner soft felt layer (i.e., the first and second combined layers). The second ceramic fiber layer further enhances the insulation effect. The first and second combined layers of this application constitute the soft felt layer, which is the core layer of the heat insulation panel assembly. Compared to a single-layer thick felt, the first and second combined layers employ a layered design, which absorbs and buffers tar while maintaining the structural elasticity of the soft felt layer. Furthermore, the second combined layer... The composite layer uses alternating layers of graphite felt and graphite paper. The graphite paper layer has a much higher density and lower porosity than the carbon felt and graphite felt layers, forming a nearly continuous and smooth barrier film between the layers. It can effectively block the permeation channels of tar vapor in the thickness direction, preventing tar from penetrating into the interior of the soft felt layer or diffusing between different felt layers. High-purity graphite has intrinsic chemical inertness and certain oleophobic properties to most organic components (such as tar), making it difficult for tar to wet, adsorb, or react with it, thus minimizing wetting and adhesion. The graphite paper layer also has good in-plane thermal conductivity, which helps to balance the temperature distribution between layers, reduce local hot spots, improve the overall thermal field uniformity, and indirectly improve the insulation efficiency and service life.
Smart Images
Figure CN224726582U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vacuum furnaces, and more particularly to a heat insulation screen assembly and a vacuum furnace. Background Technology
[0002] Heat shield assemblies are commonly used in vacuum furnaces for thermal insulation. Existing heat shield assemblies are made of a single carbon felt or graphite felt. During carbon material processing (such as graphitization), they are exposed to an environment rich in highly viscous tar vapors such as polycyclic aromatic hydrocarbons and asphaltenes. These vapors penetrate, wet, and adsorb into the high specific surface area fibers and pores of the felt, causing the following problems: 1. Pore blockage and hardening: After condensation, the tar blocks a large number of micropores and gaps in the felt, significantly reducing the material's porosity and destroying its original excellent thermal insulation performance (although gas convection heat transfer is weakened under vacuum, the solid-phase heat transfer path is significantly enhanced due to the tar "bonding" the fibers). 2. Fiber bonding and embrittlement: As a viscous medium, the tar bonds and solidifies the originally loose and slippery fibers, causing the felt to harden and become embrittled, losing its compressive resilience. This not only drastically reduces the thermal insulation performance (increases the thermal conductivity), but also makes it more prone to cracking and peeling under thermal stress, significantly shortening its lifespan and increasing energy consumption and downtime maintenance frequency. Utility Model Content
[0003] This application provides a heat insulation screen assembly and a vacuum furnace, which can avoid pore blockage and hardening, and improve heat preservation efficiency and service life.
[0004] In a first aspect, this application provides a heat insulation screen assembly, including a first ceramic fiber layer, a second ceramic fiber layer, a first composite layer and a second composite layer arranged sequentially; the first composite layer includes multiple carbon felt layers arranged sequentially; the second composite layer includes multiple graphite felt layers arranged at intervals and a graphite paper layer disposed between two adjacent graphite felt layers.
[0005] Preferably, the first ceramic fiber layer is configured as an aluminum ceramic fiber board; the thickness of the first ceramic fiber layer is 20 mm to 50 mm.
[0006] Preferably, the second ceramic fiber layer is configured as a zirconium ceramic fiber board; the thickness of the second ceramic fiber layer is 10 mm to 30 mm.
[0007] Preferably, the first composite layer comprises five to ten carbon felt layers.
[0008] Preferably, the thickness of the carbon felt layer is 8 mm to 15 mm.
[0009] Preferably, the second composite layer comprises three to six graphite felt layers, with at least one graphite paper layer disposed between two adjacent graphite felt layers.
[0010] Secondly, this application provides a vacuum furnace, including a furnace shell, a furnace door, and a heat shield assembly; the furnace shell is provided with an opening, and the furnace door is provided at the opening of the furnace shell for sealing the furnace shell; heat shield assemblies are provided on the inner side of both the furnace shell and the inner side of the furnace door.
[0011] Preferably, it also includes a locking bolt assembly that passes sequentially through the first ceramic fiber layer, the second ceramic fiber layer, the first composite layer, and the second composite layer. The locking bolt assembly also passes through the furnace shell or furnace door to lock the heat insulation screen assembly to the inside of the furnace shell or furnace door.
[0012] Preferably, a steel structure frame is provided on the outer side of the furnace shell; the steel structure frame includes a wire mesh and a steel skeleton, with the wire mesh attached to the outer periphery of the furnace shell and the steel skeleton attached to one side of the wire mesh.
[0013] Preferably, the cross-sectional shape of the furnace shell is configured as a polygon.
[0014] The heat insulation shield assembly and vacuum furnace of this application have at least the following beneficial effects:
[0015] The first ceramic fiber layer of this application, serving as the first line of defense closest to the furnace shell, provides excellent structural rigidity, compressive strength, and resistance to airflow erosion. The alumina matrix of the first ceramic fiber layer is inert to tar, effectively blocking and dispersing most of the initial tar vapor flow, preventing its direct and substantial backflow into the inner soft felt layer (i.e., the first and second combined layers). The second ceramic fiber layer further enhances the insulation effect. The first and second combined layers of this application constitute the soft felt layer, which is the core layer of the heat insulation panel assembly. Compared to a single-layer thick felt, the first and second combined layers employ a layered design, which absorbs and buffers tar while maintaining the structural elasticity of the soft felt layer. Furthermore, the second combined layer... The composite layer uses alternating layers of graphite felt and graphite paper. The graphite paper layer has a much higher density and lower porosity than the carbon felt and graphite felt layers, forming a nearly continuous and smooth barrier film between the layers. It can effectively block the permeation channels of tar vapor in the thickness direction, preventing tar from penetrating into the interior of the soft felt layer or diffusing between different felt layers. High-purity graphite has intrinsic chemical inertness and certain oleophobic properties to most organic components (such as tar), making it difficult for tar to wet, adsorb, or react with it, thus minimizing wetting and adhesion. The graphite paper layer also has good in-plane thermal conductivity, which helps to balance the temperature distribution between layers, reduce local hot spots, improve the overall thermal field uniformity, and indirectly improve the insulation efficiency and service life. Attached Figure Description
[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0017] Figure 1 This is a cross-sectional view of the heat insulation shield assembly of this application;
[0018] Figure 2 This is an isometric drawing of the vacuum furnace of this application;
[0019] Figure 3 It is an isometric view of the furnace shell and heat shield assembly;
[0020] Figure 4 yes Figure 3 The front view;
[0021] Figure 5 yes Figure 3 AA view in the middle;
[0022] Figure 6 yes Figure 5 Enlarged view of point A in the middle;
[0023] The annotations in the attached figures are explained as follows:
[0024] 100. Heat insulation shield assembly;
[0025] 101. First ceramic fiber layer;
[0026] 102. Second ceramic fiber layer;
[0027] 103. First composite layer; 1031. Carbon felt layer;
[0028] 104. Second composite layer; 1041. Graphite felt layer; 1042. Graphite paper layer;
[0029] 200. Vacuum furnace;
[0030] 201. Furnace shell;
[0031] 202. Furnace door;
[0032] 203. Locking bolt assembly;
[0033] 204. Wire mesh;
[0034] 205. Steel frame. Detailed Implementation
[0035] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.
[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used merely 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. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.
[0037] like Figure 1 As shown, this embodiment discloses a heat insulation screen assembly and a vacuum furnace. The heat insulation screen assembly 100 can be used for high-temperature (>2000°C) processing of carbon materials with high weight loss (approximately >5%). The heat insulation screen assembly 100 of this embodiment will be introduced first.
[0038] like Figure 1 As shown, the heat insulation shield assembly 100 includes a first ceramic fiber layer 101, a second ceramic fiber layer 102, a first composite layer 103, and a second composite layer 104 arranged sequentially from the outside to the inside. The second composite layer 104 is located on the side closest to the heat source. The inside-outside direction (i.e., the thickness direction) in this embodiment is shown in [reference needed]. Figure 1 As shown by arrow P.
[0039] like Figure 1 As shown, the first ceramic fiber layer 101 is configured as a high-alumina ceramic fiber board, which is manufactured using alumina as the matrix. In this embodiment, the thickness of the high-alumina ceramic fiber board is 20-50 mm, where mm represents millimeters. In this embodiment, the thickness of the high-alumina ceramic fiber board is preferably 30 to 40 mm. It should be noted that the first ceramic fiber layer 101 can also be configured as an existing ceramic fiber board.
[0040] like Figure 1As shown, the first ceramic fiber layer 101 in this embodiment can effectively block and disperse most of the initial tar vapor flow, and prevent tar from directly and massively flowing back and impacting the inner soft felt layer after the furnace shell 201 temperature rises. The specific principle is as follows: when organic components diffuse from the inside of the heat insulation panel assembly 100 outwards, the graphite paper layer 1042 acts as a barrier, blocking the tar at the innermost surface layer of the heat insulation panel assembly 100. During carbon material processing, large-molecule volatile organic components often escape at lower temperatures (200-500°C), and the graphite paper layer 1042 cannot completely intercept these volatile organic components. Some organic components will escape from the heat insulation panel assembly 100, contact the relatively low-temperature furnace shell 201, and condense. Then, as the processing temperature increases... As the temperature rises, the temperature of the furnace shell 201 also rises. The volatile components that have condensed will re-evaporate and penetrate inward from the furnace shell 201. Therefore, the outermost layer uses a more corrosion-resistant ceramic material. Ceramic is more resistant to tar corrosion. Since its main components are metal oxides such as Al2O3, SiO2, and ZrO2, these materials are inorganic non-metals with extremely high chemical inertness. They do not have chemical affinity with organic tar components, have low surface energy, and exhibit "oil repellency". Tar molecules have difficulty reacting chemically with its surface or undergoing strong physical adsorption, just like water droplets on a lotus leaf, which are not easy to wet and spread. On the other hand, carbon and the tar produced by high-temperature decomposition (mainly composed of various hydrocarbons and free carbon) are chemically homologous and have excellent affinity and wettability.
[0041] like Figure 1 As shown, the second ceramic fiber layer 102 is configured as a high-zirconium ceramic fiber board. In this embodiment, the thickness of the high-zirconium ceramic fiber board is 10-30 mm, and preferably 20 to 25 mm. The second ceramic fiber layer 102 in this embodiment has a dense inorganic oxide fiber structure, with ZrO2 as its main component, exhibiting extremely low organic matter wettability and adsorption. Because the high-zirconium ceramic fiber board has higher temperature resistance, it is designed to be located in a more inner layer, which improves the service life of the inner soft felt layer.
[0042] like Figure 1 As shown, both the first combined layer 103 and the second combined layer 104 in this embodiment adopt a multi-layer structure to form the core layer of the heat insulation screen assembly 100.
[0043] like Figure 1 As shown, the first composite layer 103 includes five to ten carbon felt layers 1031, which are sequentially bonded together in the heat source transfer direction (i.e., the thickness direction). The thickness of a single carbon felt layer 1031 is 8-15 mm, and in this embodiment, the thickness of a single carbon felt layer 1031 is preferably 10 to 12 mm.
[0044] like Figure 1As shown, the second composite layer 104 includes a plurality of graphite felt layers 1041 and a plurality of graphite paper layers 1042. The graphite felt layers 1041 are arranged sequentially at intervals in the heat source transfer direction. At least one graphite paper layer 1042 is arranged between two adjacent graphite felt layers 1041. In this embodiment, it is preferable that a graphite paper layer 1042 is bonded between two adjacent graphite felt layers 1041.
[0045] like Figure 1 As shown, in this embodiment, the second composite layer 104 preferably includes three to six graphite felt layers 1041, for example, four or five graphite felt layers 1041.
[0046] In this embodiment, both the first composite layer 103 and the second composite layer 104 adopt a layered design. Compared with a single-layer thick felt, the layered design has the following key advantages:
[0047] Tar absorption and buffering: The interlayer interface provides additional porosity and allowance space, allowing a small amount of tar vapor that flows back through the ceramic fiber layer (i.e., the first ceramic fiber layer 101 and the second ceramic fiber layer 102) barrier to condense, disperse and temporarily contain in this area, avoiding the formation of a continuous, dense tar-impregnated layer inside a single material.
[0048] Maintaining structural elasticity: Even if the layered structure is slightly wetted locally, it can still maintain a certain degree of compressive resilience and interlayer slippage, preventing overall hardening and embrittlement. The graphite felt layer 1041 is located in a higher temperature region, and its higher degree of graphitization provides better high-temperature stability and relatively lower tar affinity.
[0049] The interlayer of graphite paper layer 1042: Graphite paper layer 1042 has a density and low porosity that are much higher than carbon felt or graphite felt, and can form a nearly continuous and smooth barrier film between layers. It can effectively block the longitudinal permeation channels of tar vapor between soft felt layers and prevent tar from penetrating into the interior of the soft felt layer or spreading between different felt layers.
[0050] Furthermore, high-purity graphite possesses intrinsic chemical inertness and a certain degree of oleophobicity to most organic components (such as tar), making it difficult for tar to wet, adsorb, or react with, thus minimizing wetting and adhesion. The 1042 graphite paper layer exhibits excellent in-plane thermal conductivity, which helps to balance the interlayer temperature distribution, reduce local hot spots, improve overall thermal field uniformity, and indirectly enhance insulation efficiency and service life.
[0051] like Figure 2As shown, this embodiment also discloses a vacuum furnace. The vacuum furnace 200 includes a furnace body and a heat insulation panel assembly 100. The heat insulation panel assembly 100 is disposed on the inner side of the furnace body and plays a role in heat insulation and heat preservation. In this embodiment, the furnace body includes a furnace shell 201 and a furnace door 202. The inner side of the furnace shell 201 and the furnace door 202 (i.e. the side closer to the heat source) is covered with the heat insulation panel assembly 100.
[0052] like Figure 3 and Figure 4 As shown, the furnace shell 201 has a hexagonal cross-sectional shape. The furnace shell 201 is shaped like a hexahedron, octahedron, or decahedron, with one end along its length being an open end for easy installation of the furnace door 202 and for material loading / unloading. The remaining surfaces are closed. The interior of the furnace shell 201 contains square spaces to facilitate material loading. In this embodiment, the furnace shell 201 has a polygonal cross-section to maximize the square space inside. These square spaces facilitate the layout of the heating elements (such as graphite heating elements) and the loading of materials.
[0053] like Figure 2 and Figure 3 As shown, the furnace door 202 is located at the open end of the furnace shell 201 and is used to close the furnace shell 201, thereby forming a sealed heating space inside the furnace shell 201.
[0054] like Figure 2 As shown, a steel frame structure is provided on the outer side of the furnace shell 201. The steel frame structure includes a wire mesh 204 and a steel skeleton 205, both made of stainless steel. The wire mesh 204 is fitted to the outer periphery of the furnace shell 201, and the steel skeleton 205 is fitted to one side of the wire mesh 204. The steel frame structure provides stable support and can accommodate the thermal expansion and contraction of the vacuum furnace 200. Notably, the outer side of the furnace door 202 does not have a wire mesh 204; the steel skeleton 205 is directly fitted to the outer side of the furnace door 202. The omission of the wire mesh 204 at the furnace door 202 is to facilitate the opening and closing of the furnace door 202.
[0055] like Figure 5 As shown, in this preferred embodiment, the heat insulation panel assembly 100 inside the furnace shell 201 protrudes outward from the opening of the furnace shell 201 along the length direction of the furnace shell 201 by a predetermined length H, specifically protruding to one side of the steel structure frame, so as to facilitate its fit with the heat insulation panel assembly 100 on the inner side of the furnace door 202. In this embodiment, the heat insulation panel assembly 100 inside the furnace shell 201 protrudes slightly 10-20mm towards the furnace door 202, so as to maximize the heat insulation effect of the heat insulation panel assembly 100.
[0056] like Figure 5 and Figure 6As shown, in this preferred embodiment, the vacuum furnace 200 further includes a plurality of locking bolt assemblies 203, which are used to lock the heat insulation panel assembly 100 to the furnace shell 201 and to the furnace door 202. Specifically:
[0057] like Figure 5 As shown, the locking bolt assembly 203 passes through the furnace shell 201, the first ceramic fiber layer 101, the second ceramic fiber layer 102, the first composite layer 103, and the second composite layer 104 sequentially from the outside to the inside, and tightens the first ceramic fiber layer 101, the second ceramic fiber layer 102, the first composite layer 103, and the second composite layer 104 on the inner side of the furnace shell 201. In this embodiment, preferably, the heat insulation screen assembly 100 is fixed to the inner side of the furnace shell 201 by multiple locking bolt assemblies 203.
[0058] The locking bolt assembly 203 passes sequentially from the outside to the inside through the furnace door 202, the first ceramic fiber layer 101, the second ceramic fiber layer 102, the first combined layer 103, and the second combined layer 104, and tightens the first ceramic fiber layer 101, the second ceramic fiber layer 102, the first combined layer 103, and the second combined layer 104 to the inside of the furnace door 202. Preferably, in this embodiment, the heat insulation screen assembly 100 is fixed to the inside of the furnace door 202 by multiple locking bolt assemblies 203.
[0059] like Figure 5 As shown, in this embodiment, the locking bolt assembly 203 includes screws, nuts and washers. It is preferred to use existing graphite bolt assemblies. The specific number and arrangement are adjusted according to the structure and size of the heat insulation screen assembly 100.
[0060] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.
Claims
1. A heat insulation screen assembly, characterized in that, It includes a first ceramic fiber layer (101), a second ceramic fiber layer (102), a first composite layer (103), and a second composite layer (104) arranged sequentially; The first composite layer (103) includes multiple layers of carbon felt (1031) arranged sequentially; The second composite layer (104) includes multiple layers of graphite felt (1041) arranged at intervals in sequence and a graphite paper layer (1042) disposed between two adjacent graphite felt layers (1041).
2. The heat insulation screen assembly according to claim 1, characterized in that, The first ceramic fiber layer (101) is configured as an aluminum ceramic fiber board; the thickness of the first ceramic fiber layer (101) is 20 mm to 50 mm.
3. The heat insulation screen assembly according to claim 1, characterized in that, The second ceramic fiber layer (102) is configured as a zirconium ceramic fiber plate; the thickness of the second ceramic fiber layer (102) is 10 mm to 30 mm.
4. The heat insulation screen assembly according to any one of claims 1 to 3, characterized in that, The first composite layer (103) comprises five to ten carbon felt layers (1031).
5. The heat insulation screen assembly according to claim 4, characterized in that, The thickness of the carbon felt layer (1031) is 8 mm to 15 mm.
6. The heat insulation screen assembly according to claim 4, characterized in that, The second composite layer (104) includes three to six graphite felt layers (1041), with at least one graphite paper layer (1042) disposed between two adjacent graphite felt layers (1041).
7. A vacuum furnace, characterized in that, It includes a furnace shell (201), a furnace door (202), and a heat insulation shield assembly (100) as described in any one of claims 1 to 6; the furnace shell (201) is provided with an opening, and the furnace door (202) is provided at the opening of the furnace shell (201) for closing the furnace shell (201); the heat insulation shield assembly (100) is provided on the inner side of the furnace shell (201) and the inner side of the furnace door (202).
8. The vacuum furnace according to claim 7, characterized in that, It also includes a locking bolt assembly (203), which passes through the first ceramic fiber layer (101), the second ceramic fiber layer (102), the first composite layer (103), and the second composite layer (104) in sequence. The locking bolt assembly (203) also passes through the furnace shell (201) or the furnace door (202) to lock the heat insulation screen assembly (100) to the inside of the furnace shell (201) or the furnace door (202).
9. The vacuum furnace according to claim 7, characterized in that, A steel frame is provided on the outside of the furnace shell (201); the steel frame includes a wire mesh (204) and a steel skeleton (205), the wire mesh (204) is attached to the outer periphery of the furnace shell (201); the steel skeleton (205) is attached to one side of the wire mesh (204).
10. The vacuum furnace according to claim 7, characterized in that, The cross-sectional shape of the furnace shell (201) is configured as a polygon.