A graphite heating device for a vacuum sintering furnace

Abstract

The application discloses a graphite heating device for a vacuum sintering furnace, and belongs to the technical field of vacuum sintering. The device comprises a heating assembly and an insulation assembly. The heating assembly is formed by sequentially splicing a plurality of flaky graphite heating sheets through angular edge connecting pieces into a multi-faceted annular open frame. The heating sheets and the edge connecting pieces jointly constitute an electric circuit. Two heating sheets connected by an insulation pad and insulated apart are arranged at the opening. The two heating sheets are both connected with heating electrodes. The heating sheets are provided with grid holes to enhance heat dissipation. The insulation assembly further comprises insulation pad II arranged outside the connecting pieces and an isolation column for external insulation. The modular splicing structure realizes lightweight and low thermal inertia of the heating body. The open frame can effectively release thermal stress and prevent cracking. In combination with the overall insulation design, the device has the advantages of fast heating, uniform heat field, long service life, safety and reliability.

Description

Technical Field

[0001] This invention relates to the field of heating devices, and more particularly to a graphite heating device for a vacuum sintering furnace. Background Technology

[0002] The development of rapid prototyping technology using metal powder has propelled the MIM (Metal Injection Molding) and 3D printing industries into a period of rapid growth. Rapid prototyping requires sintering of the formed samples to achieve the density of metal. As the core equipment for high-temperature material processing, the performance of the heating device in a vacuum sintering furnace directly affects the efficiency of the sintering process and the quality of the product. Graphite, due to its high-temperature stability, good thermal conductivity, and chemical corrosion resistance, has become the preferred material for heating devices in vacuum sintering furnaces. However, existing graphite heating devices still have shortcomings in terms of structural design, thermal efficiency, and service life.

[0003] Currently, most existing graphite heaters use graphite heating strips, graphite heating rods, and connecting blocks to form a circuit. This structure has many parts and is complex to install. It is easy to make mistakes during installation, causing irreparable damage. Moreover, when a component is damaged, the entire heater needs to be disassembled and replaced. This structure requires highly professional installers and is time-consuming and labor-intensive, which is not conducive to the actual production environment. In addition, this type of heater has many connection points between heating rods or heating elements, which can easily lead to loose connections and uneven heating due to localized overheating. Summary of the Invention

[0004] This invention addresses the shortcomings of existing graphite heaters, which have numerous structural components forming the circuit and are complex to install and replace, by providing a graphite heating device for a vacuum sintering furnace.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a graphite heating device for a vacuum sintering furnace, comprising a heating component and an insulating component. The heating component includes a plurality of sheet-shaped heating plates, a plurality of edge connectors, and heating electrodes. The insulating component includes an insulating pad. The plurality of heating plates are sequentially connected by the edge connectors to form a multi-faceted annular frame. Two adjacent heating plates are spaced apart to drive the plurality of heating plates to be connected in an annular open frame shape. The insulating pad is connected to the two spaced heating plates. Each of the two spaced heating plates is connected to at least one heating electrode.

[0006] By adopting the above technical solution, the traditional integral heating element is innovated into a multi-faceted annular open frame structure composed of sheet-like heating elements. This significantly reduces the overall weight of the heating element, lowers thermal inertia, and results in faster heating and cooling rates and lower energy consumption. The open frame structure provides buffer space for its own thermal expansion when heated, effectively preventing structural cracking caused by thermal stress concentration and extending its service life. The insulating pad not only provides insulation between the heating elements but also ensures the structural stability of the annular open frame.

[0007] The present invention is further configured such that the heating element has a plurality of grid holes.

[0008] By adopting the above technical solution, the design of the grid holes significantly increases the heat dissipation surface area while ensuring the structural strength of the heating element, thereby improving the thermal radiation efficiency and making the thermal field inside the furnace more uniform. At the same time, the grid holes also serve as gas channels, which facilitates the discharge of volatile substances during sintering, avoids local contamination, and further reduces the weight of the heating element.

[0009] The present invention is further configured such that: the edge connector includes a first connecting segment and a second connecting segment, the first connecting segment and the second connecting segment are arranged at an angle, the first connecting segment and the second connecting segment are respectively connected to a heating element, and the heating element and the edge connector form a circuit.

[0010] By adopting the above technical solution, the angled edge connectors not only realize the mechanical connection and positioning between adjacent heating elements, forming a stable polyhedral frame, but more importantly, they themselves act as a conductive path, connecting each independent heating element in series into a complete electrical circuit, ensuring that the current can flow smoothly through the entire heating body and achieve uniform heating.

[0011] The present invention is further configured such that: the insulating component further includes an insulating pad two, the heating element is connected to the inner side of the angle formed between the connecting segment one and the connecting segment two, and the insulating pad two is connected to the outer side of the angle formed between the connecting segment one and the connecting segment two.

[0012] By adopting the above technical solution, the insulating pad two is placed at the outer corner of the edge connector, forming an inner and outer clamping force with the inner heating element. This design greatly enhances the structural strength and stability of the connection node, effectively preventing the heating element from loosening or shifting under long-term high-temperature conditions. At the same time, it further strengthens the insulation protection of this critical part, eliminating electric field concentration or creepage phenomena that may occur due to sharp edges, and improving the safety and reliability of the equipment.

[0013] The present invention is further configured such that: a positioning step for limiting and abutting the heating element is provided on the inner side of the included angle formed by the first connecting segment and the second connecting segment.

[0014] By adopting the above technical solution, the positioning steps provide a precise positioning reference for the installation of heating elements, making the assembly process simpler and faster, and ensuring that the relative positions of all heating elements in the frame are consistent, thereby ensuring that the final heating field has good symmetry and uniformity.

[0015] The present invention is further configured such that: at least two insulating pads are provided inside the opening of the multi-faceted annular frame, and an insulating pad is provided at each end of the opening of the multi-faceted annular frame.

[0016] By adopting the above technical solution, insulating pads are set at key stress points at both ends of the opening, which can evenly disperse the deformation stress caused by thermal expansion at the opening, avoid stress concentration on a single pad, greatly enhance the structural rigidity and long-term stability of the opening frame, and prevent the frame from deforming or being damaged due to repeated thermal cycles.

[0017] The present invention is further configured such that: the heating element and the edge connector are connected by fasteners, and the heating element, edge connector, heating electrode and fastener are all made of graphite material.

[0018] By adopting the above technical solution, all key components are made of high-purity graphite, ensuring that the entire heating device has excellent high-temperature resistance, thermal stability, and corrosion resistance. More importantly, the same material means that each component has a consistent coefficient of thermal expansion, allowing them to expand and contract synchronously at high temperatures. This fundamentally avoids internal stress caused by thermal mismatch and prevents loose connections or component breakage.

[0019] The present invention is further configured such that: the edge connector is elongated, and the insulating component further includes a plurality of insulating isolation pillars, which are connected to the outer surface of the connecting section one and the connecting section two forming an angle and / or the end face of the edge connector.

[0020] By adopting the above technical solution, the insulating isolation column establishes a safe insulating isolation zone between the heating element and the external support structure of the furnace body, effectively preventing the risk of current leakage to the furnace body through the frame. This not only improves electrical safety but also avoids ineffective heat conduction to the external structure, thereby improving thermal efficiency.

[0021] The present invention is further configured such that: the insulating pad one and / or the insulating pad two and / or the insulating isolation column of the insulating component are made of insulating material.

[0022] By adopting the above technical solution, all insulating components are made of high-temperature resistant insulating materials, such as graphite felt, hard felt or special ceramics, which ensures that the heating element and the furnace body, as well as the various live parts of the heating element, always maintain a reliable insulation state in the entire high-temperature working environment, thus ensuring the absolute safety of the equipment in long-term operation.

[0023] The present invention is further configured such that the heating electrode and the heating element are detachably connected.

[0024] This invention, employing the above technical solutions, achieves significant technical advantages: By designing the heating element as a multi-faceted annular open frame assembled from sheet-like graphite heating plates via edge connectors, and combining it with multi-layered insulation components, it comprehensively achieves a balance of lightweight, high efficiency, long lifespan, and high safety. This structure not only provides rapid heating, uniform thermal field, and significant energy savings, but also effectively releases thermal stress through its unique opening and flexible connection design, avoiding the cracking problem common in traditional graphite heating elements. The choice of all-graphite material ensures excellent thermal matching and high-temperature resistance, while the systematic insulation design constructs a comprehensive safety barrier. This invention is particularly suitable for experimental or small-scale industrial vacuum graphite sintering furnaces with extremely high requirements for temperature uniformity, temperature control accuracy, and equipment reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the graphite heating device in a vacuum sintering furnace. Figure 2 This is a schematic diagram of the heating element.

[0026] The parts referred to by the numbers in the above attached figures are as follows: 1. Heating element; 11. Grille hole; 2. Edge connector; 21. Connecting section one; 22. Connecting section two; 23. Positioning step; 3. Heating electrode; 4. Fastener; 5. Insulating pad one; 51. Limiting step; 6. Insulating pad two; 7. Insulating isolation column. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0028] Example 1: A graphite heating device for a vacuum sintering furnace, see [link / reference]. Figure 1 It includes heating components and insulation components.

[0029] See Figure 1 The heating assembly includes several sheet-shaped heating elements 1, several edge connectors 2 for connecting the heating elements 1, and heating electrodes 3 for the circuit loop. The heating elements 1 have a sheet-like structure, which is square in this embodiment, but is not limited to square and can also be other polygons. Figure 2The heating element 1 is formed by hollowing out several equally sized rectangular grid holes 11 in the middle of a whole graphite plate. The edges of the grid holes 11 of the heating element 1 are chamfered, which can reduce local hot spots and avoid the weak points of fatigue fracture due to stress concentration. It helps to improve the temperature uniformity of the heated part and maintain the stability of the structure. It can also facilitate gas flow and increase the thermal convection efficiency.

[0030] See Figure 1 The edge connector 2 is integrally formed from a long strip of graphite block with an L-shaped cross-section. The edge connector 2 includes a first connecting section 21 and a second connecting section 22. The first connecting section 21 and the second connecting section 22 are set at an angle to form an L-shape. The first connecting section 21 and the second connecting section 22 are respectively connected to the heating element 1, and the edge connector 2 is connected to the heating element 1 by fasteners 4.

[0031] Several heating elements 1 are sequentially connected by edge connectors 2 to form a multi-faceted annular frame. In this embodiment, a four-faced annular frame is formed, but it is not limited to four faces; it can also be a multi-faceted annular frame with three or more faces. This embodiment uses a four-faced annular frame, so there are four edge connectors 2 in total. The first connecting segment 21 and the second connecting segment 22 are set at 90 degrees to each other. The included angle between them can be adjusted according to the number of faces of the annular frame. For example, when it is a six-faced annular frame, the first connecting segment 21 and the second connecting segment 22 are set at 120 degrees to each other. One face of the multi-faceted annular frame is composed of two heating elements 1 spaced apart. The two heating elements 1 are the shorter sides and their width is shorter. The two adjacent heating elements 1 are spaced apart, which drives the multifaceted annular frame to be an open frame shape. There are two heating electrodes 3. Each of the two spaced heating elements 1 is fixedly connected to a heating electrode 3 by a graphite fastener 4. The heating electrode 3 is detachably connected to the heating element 1 by the fastener 4. Since the multifaceted annular frame is open, and the heating elements 1, edge connectors 2, heating electrodes 3 and fasteners 4 are all made of graphite, the two heating electrodes 3 are respectively connected to the positive and negative terminals of the power supply, thereby driving several heating elements 1 and several edge connectors 2 to form a conductive circuit.

[0032] The insulation assembly includes an insulating pad 5, an insulating pad 6, and an insulating isolation column 7. The insulating pad 5 abuts against the two short-side heating elements 1 that are spaced apart. The insulating pad 5 has symmetrically arranged limiting steps 51 on both sides. The limiting steps 51 are used to restrict and isolate the two heating elements 1 that are spaced apart, thereby preventing direct contact and short circuit. There are at least two insulating pads 5. In this embodiment, there are two insulating pads 5, but it is not limited to two or more. Insulating pads 5 are provided at both ends of the opening of the multi-faceted annular frame. If the opening of the multi-faceted annular frame is too long, an insulating pad 5 can also be provided in the middle of the opening to increase the stability of the overall structure.

[0033] Heating element 1 is connected to the inner side of the angle formed by connecting section 1 21 and connecting section 2 22 by fastener 4. Several insulating pads 2 6 are provided and are fixedly connected to the outer side of the angle formed by connecting section 1 21 and connecting section 2 22 by snap-fit ​​or fastener 4. Several insulating pads 2 6 are provided, mainly to drive the entire graphite heating device to be detached from the vacuum sintering furnace frame. Insulating pad 1 5 and insulating pad 2 6 ensure that the current can be conducted according to the predetermined route to ensure the normal operation of the heater, to ensure heating uniformity, and to avoid the risk of short circuit and creepage.

[0034] The inner side of the angle formed by connecting section 1 21 and connecting section 2 22 is provided with a positioning step 23 for limiting and abutting the heating element 1. The positioning step 23 can position the heating element 1, which facilitates the initial installation and subsequent replacement.

[0035] Several insulating isolation posts 7 are provided. The edge connector 2 is long and narrow. Several insulating isolation posts 7 are connected to the outer side of the angle formed between the first connecting section 21 and the second connecting section 22 and / or the end face of the edge connector 2. The insulating isolation post 7 is cylindrical and has a thread at one end. The edge connector 2 has several threaded holes. The insulating isolation post 7 is threadedly connected to the edge connector 2. The insulating pad 1 and / or insulating pad 2 and / or insulating isolation posts of the insulating component are made of insulating material. In this embodiment, they are all made of 99% alumina ceramic, but it is not limited to 99% alumina ceramic. Other insulating materials can also be used.

Claims

1. A graphite heating device for a vacuum sintering furnace, comprising a heating assembly and an insulation assembly, characterized in that, The heating assembly includes several sheet-shaped heating plates (1), several edge connectors (2), and heating electrodes (3). The insulation assembly includes an insulating pad (5). Several heating plates (1) are connected sequentially through edge connectors (2) to form a multi-faceted annular frame. Two adjacent heating plates (1) are spaced apart to drive several heating plates (1) to be connected in an annular open frame shape. The insulating pad (5) is connected to the two spaced heating plates (1). Each of the two spaced heating plates (1) is connected to at least one heating electrode (3).

2. The graphite heating device for a vacuum sintering furnace according to claim 1, characterized in that, The heating element (1) has several grid holes (11).

3. A graphite heating device for a vacuum sintering furnace according to claim 1, characterized in that, The edge connector (2) includes a first connecting segment (21) and a second connecting segment (22). The first connecting segment (21) and the second connecting segment (22) are set at an angle. The first connecting segment (21) and the second connecting segment (22) are respectively connected to a heating element (1). The heating element (1) and the edge connector (2) form a circuit.

4. A graphite heating device for a vacuum sintering furnace according to claim 3, characterized in that, The insulating assembly also includes an insulating pad two (6), the heating element (1) is connected to the inside of the angle formed by connecting segment one (21) and connecting segment two (22), and the insulating pad two (6) is connected to the outside of the angle formed by connecting segment one (21) and connecting segment two (22).

5. A graphite heating device for a vacuum sintering furnace according to claim 3, characterized in that, The inner side of the angle formed by the first connecting segment (21) and the second connecting segment (22) is provided with a positioning step (23) for limiting and abutting the heating element (1).

6. A graphite heating device for a vacuum sintering furnace according to claim 1, characterized in that, At least two insulating pads (5) are provided inside the opening of the multi-faceted annular frame, and an insulating pad (5) is provided at both ends of the opening of the multi-faceted annular frame.

7. A graphite heating device for a vacuum sintering furnace according to claim 1, characterized in that, The heating element (1) and the edge connector (2) are connected by fasteners (4). The heating element (1), edge connector (2), heating electrode (3) and fasteners (4) are all made of graphite.

8. A graphite heating device for a vacuum sintering furnace according to claim 4, characterized in that, The edge connector (2) is elongated, and the insulating assembly also includes a plurality of insulating isolation columns (7), which are connected to the outer side of the connecting section one (21) and the connecting section two (22) forming an angle and / or the end face of the edge connector (2).

9. A graphite heating device for a vacuum sintering furnace according to claim 8, characterized in that, The insulating pad one (5) and / or insulating pad two (6) and / or insulating isolation column (7) of the insulating component are made of insulating material.

10. A graphite heating device for a vacuum sintering furnace according to claim 1, characterized in that, The heating electrode (3) is detachably connected to the heating element (1).

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