A vacuum autoclave and method with built-in conductive connection

Abstract

This invention discloses an integral vacuum hot press furnace and its operating method, belonging to the field of vacuum hot pressing equipment. The hot press furnace includes an integrally formed closed furnace frame, with independently openable and closable front and rear door assemblies respectively located at its front and rear ends. The conductive heating system includes multiple independently controlled conductive heating circuits, wherein the circuit ends located on the inner wall of the door are connected to contact electrodes, and the circuit ends located on the inner wall of the furnace are designated as inner door electrodes. A detachable conductive connection structure is installed on the furnace wall, electrically connecting the contact electrodes to the inner door electrodes when the door is closed, forming a complete heating circuit. This invention eliminates the need for multiple electrode holes in the furnace wall or door, significantly improving the reliability of the vacuum seal.

Description

Technical Field

[0001] This invention relates to the field of vacuum hot press furnace technology, and more specifically to a vacuum hot press furnace and method with built-in conductive connection. Background Technology

[0002] A vacuum autoclave is a special thermal processing equipment used to heat and pressurize workpieces in a vacuum environment to achieve solid-state diffusion bonding or hot-pressing sintering. It is widely used in aerospace, electronic packaging, powder metallurgy, and other fields. Such equipment typically includes a furnace body, a vacuum system, a pressurization system, and a heating system. To achieve the high-temperature (typically above 1000℃) operating environment inside the furnace, the heating system often employs resistance heating, with strip or rod-shaped heating elements arranged on the inner side of the furnace wall and inside the pressure head. The furnace body is usually designed as a frame structure with only a front door. To ensure the airtightness of the vacuum chamber, electrode introduction devices for introducing large currents are required on the furnace wall and door.

[0003] In existing vacuum autoclaves, the heating system typically uses electrodes that penetrate the furnace wall or door to supply power from an external source to the internal heating elements. Specifically, multiple electrode holes are made in the furnace wall or door, and metal electrode rods are fixed by flanges and insulation components. One end of the electrode rod is connected to the heating element inside the furnace, and the other end is connected to an external cable.

[0004] This structure presents the following technical problems: First, the presence of electrode holes increases the risk of leakage in the vacuum seal, especially under long-term high-temperature cycling, where aging of the insulation and deformation of the seals can easily lead to a decrease in vacuum and affect welding quality. Second, the electrode holes on the door require flexible cables to accommodate the opening and closing of the door, resulting in complex and messy wiring around the door, and frequent movement can easily cause cable wear or poor connection. Third, to meet the requirement of uniform heating of large workpieces, multiple independent heating circuits are often required to be arranged along the height of the furnace body, and each circuit requires a corresponding electrode, further increasing the number of openings in the furnace wall and the difficulty of sealing.

[0005] Therefore, how to simplify the electrode introduction structure of the vacuum hot press furnace, improve the reliability of vacuum sealing, and ensure the electrical connection stability of the door heating element are technical problems that urgently need to be solved in this field. Summary of the Invention

[0006] To address the problems in the prior art, the present invention provides a vacuum hot press furnace and method with built-in conductive connection. By forming a built-in clamping electrical connection between the touch electrode set on the door assembly, the door inner electrode set on the furnace wall, and the movable pull rod when the door is closed, multiple electrode holes are eliminated from the furnace wall or door, significantly improving the reliability of vacuum sealing.

[0007] The technical solution adopted by this invention to solve its technical problem is a vacuum hot press furnace with built-in conductive connection, including a furnace frame for creating a vacuum environment, an upper pressure head assembly and a lower pressure head assembly disposed in the vacuum hot press chamber, and a conductive heating system and a cooling system integrated within the frame. The furnace frame is a rectangular closed structure with open front and rear ends, and is equipped with a front door assembly and a rear door assembly that can be opened and closed independently. The conductive heating system includes at least three independently controllable conductive heating circuits, two of which are respectively located in the upper pressure head assembly and the lower pressure head assembly, and the remaining circuits are located inside the furnace frame and the front door assembly and the rear door assembly. The conductive heating circuits located on the inner walls of the front and rear door assemblies are connected to touch electrodes at their ends; the conductive heating circuits located on the inner walls of the furnace frame are configured as inner door electrodes. The hot press furnace also includes a conductive connection structure electrically connected to the electrode inside the door. The conductive connection structure is installed on the furnace wall of the furnace body frame and is used to electrically connect the touch electrode to the corresponding electrode inside the door when the front door assembly and / or the rear door assembly are in the closed state, so as to form a complete conductive heating circuit.

[0008] Furthermore, the conductive connection structure includes an inlet electrode, an outlet electrode, and an intermediate electrode disposed on the left and right furnace walls; the inlet electrode is used to connect the power supply to the furnace; the outlet electrode is used to lead the furnace circuit to the outside; and the intermediate electrode is used to realize the series transition of the furnace circuit without connecting it to the outside of the furnace.

[0009] Furthermore, the lead-out electrode and the intermediate electrode each include: A cylinder fixed to the outside of the furnace wall; A pull rod that is connected to and driven by the piston rod of the cylinder to reciprocate; An internal flange fixed to the inside of the furnace wall; An external flange fixed to the outside of the furnace wall; the tie rod movably passes through the furnace wall, the internal flange, and the external flange; A locking nut is provided at one end of the pull rod located inside the furnace; the inner electrode of the door is sleeved on the pull rod and is axially limited between the inner flange of the furnace and the locking nut, and the inner electrode of the door has a joint for engaging with a contact electrode on the door assembly; The lead-out electrode has a terminal block at one end outside the furnace, which is used to connect to an external power supply cable.

[0010] Furthermore, the touch electrode includes a connecting portion and a forked engagement portion at its end. The forked engagement portion includes two parallel and spaced-apart branch arms, with a U-shaped groove formed between the two branch arms and engaging with the pull rod.

[0011] Furthermore, the lead-in electrode and / or lead-out electrode are provided with axial circulating cooling water channels.

[0012] Furthermore, temperature sensors are provided on the inlet electrode, outlet electrode, and intermediate electrode, and the temperature sensors are electrically connected to the control system. The control system has a preset safe temperature threshold and is configured to automatically cut off the power supply of the corresponding conductive heating circuit, maintain the operation of the cooling system, and issue an alarm signal when the temperature detected by any temperature sensor exceeds the safe temperature threshold.

[0013] Furthermore, the front door assembly is configured to move sequentially in two directions: first, it moves laterally, the direction of which is parallel to the cylinder or the cylinder extension direction, so that the forked joint of the touch electrode reaches a predetermined engagement position in space that is radially aligned with the corresponding pull rod; then, it moves longitudinally, driving the forked joint of the touch electrode toward the furnace, so that the U-shaped groove of the forked joint smoothly engages with the corresponding pull rod, completing the insertion and engagement of the touch electrode and the corresponding pull rod, so that the touch electrode and the conductive connection structure are connected.

[0014] And / or, the rear door assembly has the same structure as the front door assembly, or the rear door assembly is configured to have longitudinal movement capability, such that when closed, the touch electrode is inserted into the corresponding conductive connection structure.

[0015] Furthermore, the cooling system is respectively arranged in the front door assembly, the rear door assembly, the furnace frame, and the upper and lower pressure head assemblies.

[0016] Furthermore, the furnace wall of the furnace body frame is integrated with the supporting bed frame as one unit.

[0017] The present invention also discloses a working method based on the aforementioned vacuum hot press furnace, comprising the following steps: S1: Place the workpiece to be processed on the lower pressure head assembly; S2: Drive the rear door assembly to move longitudinally to close, so that the contact electrode on its inner wall is connected to the corresponding conductive connection structure; S3: Drive the front door assembly to move laterally first, aligning the touch electrodes on its inner wall with the corresponding conductive connection structure axially; then move longitudinally, so that the touch electrodes and the conductive connection structure are connected. S4: After the limit switch on the front door assembly detects that the door is closed, the drive cylinder moves the pull rod out of the furnace, pressing the contact electrode and the inner electrode of the door together to establish a stable current path. The current flow path is as follows: the current is introduced from an inlet electrode, flows sequentially through the strip heating assembly on the inner side of one furnace wall, the strip heating assembly on the inner side of the front door assembly or the rear door assembly, the strip heating assembly on the inner side of the other furnace wall, and the strip heating assembly on the inner side of another door assembly, and finally exits from the outlet electrode on the same side as the inlet electrode, forming a series heating circuit. S5: Start the vacuum pump unit to evacuate the vacuum thermocompression chamber; S6: Depending on the height of the workpiece, selectively activate one or more sets of conductive heating circuits to heat the furnace. S7: Drive the upper pressure head assembly to apply pressure to the workpiece while maintaining a high temperature environment for diffusion welding or hot pressing sintering. S8: After welding is completed, stop heating, start the cooling system to cool down, and break the vacuum after the temperature drops. S9: Drive the front door assembly to first exit longitudinally and de-energize, then move it laterally; drive the rear door assembly to open longitudinally directly; remove the processed workpiece.

[0018] Compared with the prior art, the present invention has the following beneficial effects: First, by designing the connection structure of the conductive heating circuit as a detachable contact electrode that connects with the electrode inside the door, the electrode through-hole required on the traditional furnace door is completely eliminated, thus eliminating the risk of vacuum leakage at the source and significantly improving the sealing reliability of the furnace body under high temperature and high vacuum conditions.

[0019] Secondly, the conductive connection structure uses a cylinder to drive the pull rod to move axially, so that a controllable clamping force is formed between the electrode inside the door and the contact electrode. The contact resistance is small and stable, and local overheating can be effectively suppressed even under high current conditions. Combined with the axial cooling water channel inside the pull rod, the heat dissipation efficiency and service life of the electrode connection components are further improved.

[0020] Furthermore, the front door assembly adopts a two-step movement method of horizontal alignment and vertical insertion, which not only ensures the precise alignment of the contact electrode and the pull rod, but also achieves smooth and shock-free electrical contact. The rear door assembly adopts a direct vertical insertion and drives the vacuum pump unit to move as a whole, which not only simplifies the operation process, but also optimizes the overall layout of the equipment and saves installation space.

[0021] In addition, the conductive heating system contains multiple independently controlled circuits, which can select to activate all or part of the heating circuits according to the height of the workpiece, achieving precise temperature control and energy saving. The shaped cooling water channel inside the door body focuses on strengthening the cooling of the sealing ring area, effectively preventing the seals from aging and deforming due to long-term high-temperature radiation. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a perspective view of the vacuum hot press furnace of the present invention; Figure 2 This is a perspective view of the furnace frame of the present invention; Figure 3 This is a front view of the furnace frame of the present invention; Figure 4 This is a left view of the furnace frame of the present invention; Figure 5 This is a rear view of the front door assembly of the present invention; Figure 6 This is a partial schematic diagram of the front door assembly of the present invention; Figure 7 This is a schematic diagram showing the interaction between the touch electrode and the door electrode of the present invention; Figure 8 This is a perspective view of the backdoor component of the present invention; Figure 9 This is a perspective view of the contact electrode of the present invention; Figure 10 This is a perspective view of the lead-out electrodes of the present invention; Figure 11 This is a perspective view of the intermediate electrode of the present invention.

[0024] In the diagram: 1. Furnace frame; 1-1. Upper furnace wall; 1-2. Lower furnace wall; 1-3. Left furnace wall; 1-4. Right furnace wall; 2. Upper pressure head assembly; 3. Lower pressure head assembly; 4. Front door assembly; 5. Rear door assembly; 6. Support frame; 7. Maintenance platform; 8. First strip heating assembly; 9. Second strip heating assembly; 10. Third strip heating assembly; 11. Fourth strip heating assembly; 12. Contact electrode; 12-1. Connecting part; 12-2. Joint part; 13. Inner electrode; 14. Lead-out electrode; 14-1. First inner flange; 14-2. First outer flange; 14-3. First cylinder; 14-4. First positioning post; 14-5. 14-6 First tie rod; 14-7 First locking nut; 14-8 Connecting block; 14-9 Connecting hole; 14-10 Water inlet; 14-11 Water outlet; 14-11 First bellows; 15 Intermediate electrode; 15-1 Second furnace inner flange; 15-2 Second furnace outer flange; 15-3 Second cylinder; 15-4 Second positioning post; 15-5 Second tie rod; 15-6 Second locking nut; 15-7 Third furnace outer flange; 16 Inlet electrode; 17 Vacuum pump assembly; 18 Support frame; 19 First circulating cooling water channel; 20 Second circulating cooling water channel; 21 Copper pipe; 22 Sealing ring; 23 Temperature sensor. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments. Example

[0026] Please see Figures 1-11 This invention provides a vacuum hot press furnace with built-in conductive connection, including a furnace frame 1 for creating a vacuum environment, an upper pressure head assembly 2 disposed within the vacuum hot press chamber, a lower pressure head assembly 3 located below it, and a conductive heating system and a cooling system integrated within the frame. The workpiece to be processed can be placed between the upper pressure head assembly 2 and the lower pressure head assembly 3 to complete diffusion welding or hot pressing sintering processes under vacuum and high temperature conditions. It should be noted that the schematic diagram of the workpiece to be processed is omitted in the accompanying drawings.

[0027] The furnace frame 1 comprises four rectangular enclosed load-bearing shells: an upper furnace wall 1-1, a lower furnace wall 1-2, a left furnace wall 1-3, and a right furnace wall 1-4. The front and rear ends of the frame are open, forming a vacuum hot-pressing chamber inside. Correspondingly, the furnace is equipped with independently openable and closable movable door assemblies, namely a front door assembly 4 and a rear door assembly 5, at the front and rear of the frame, respectively, to achieve sealing and opening of the vacuum hot-pressing chamber, allowing operators to observe the workpiece alignment from both sides.

[0028] Preferably, the vacuum hot press furnace is provided with a support frame 6 around its perimeter, and a maintenance platform 7 is provided on the top of the support frame 6. The top of the maintenance platform 7 is provided with a hoisting hole for overall hoisting and maintenance. Example

[0029] This embodiment describes a conductive heating system for a vacuum hot press furnace with built-in conductive connection, based on Embodiment 1: The conductive heating system is used to provide a heat source to the vacuum hot pressing chamber, and it includes at least three independently controllable conductive heating circuits. Two of these circuits are respectively located in the upper pressure head assembly 2 and the lower pressure head assembly 3 to dynamically heat their respective pressure heads, while the remaining circuits are arranged inside the furnace frame 1 and the front and rear door assemblies.

[0030] In a preferred embodiment, the structure of any group of conductive heating circuits in the remaining circuits includes a strip heating component made of a high melting point conductive metal material, preferably a molybdenum strip, which is arranged in a serpentine pattern within the vacuum hot pressing chamber. Specifically, it includes a first strip heating component 8 disposed on the inner wall of the front door component 4, a second strip heating component 9 disposed on the inner wall of the rear door component 5, a third strip heating component 10 disposed on the inner side of the left furnace wall 1-3 of the furnace frame 1, and a fourth strip heating component 11 disposed on the inner side of the right furnace wall 1-4 of the furnace frame.

[0031] To achieve a built-in conductive connection without exposed electrode holes, the ends of the first strip heating assembly 8 and the second strip heating assembly 9 are respectively connected to touch electrodes 12 made of conductive material; the beginning and end ends of the third strip heating assembly 10 and the fourth strip heating assembly 11 are set as door-in-door electrodes 13. The touch electrodes 12 and the door-in-door electrodes 13 are electrically connected in a separable manner when the door is closed through a conductive connection structure, thereby completely eliminating the traditional structure of reserved electrode holes on the outside of the furnace door and ensuring the vacuum environment inside the furnace from the source.

[0032] Specifically, the touch electrode 12 includes a connecting part 12-1 and a fork-shaped engagement part 12-2 at its end. The connecting part 12-1 is fixed to the door assembly, and the fork-shaped engagement part 12-2 includes two parallel and spaced-apart branch arms, with a U-shaped groove formed between the two branch arms for engaging the conductive connection structure.

[0033] The conductive connection structure includes an inlet electrode 16, an outlet electrode 14, and an intermediate electrode 15 disposed on the left and right furnace walls; the inlet electrode 16 is used to connect the power supply to the furnace; the outlet electrode 14 is used to lead the furnace circuit to the outside; the intermediate electrode 15 is used to realize the series transition of the furnace circuit without connecting it to the outside of the furnace.

[0034] The lead-out electrode 14 and the intermediate electrode 15 each include: a cylinder fixed to the outside of the furnace wall, a pull rod connected to and driven by the piston rod of the cylinder to reciprocate, an inner flange fixed to the inside of the furnace wall, and an outer flange fixed to the outside of the furnace wall; the pull rod movably passes through the furnace wall, the inner flange, and the outer flange; it also includes a locking nut located at one end of the pull rod inside the furnace; the inner electrode is sleeved on the pull rod and axially limited between the inner flange and the locking nut, and the inner electrode has a joint for engaging with a contact electrode on the door assembly; wherein, the pull rod of the lead-out electrode has a terminal block at one end outside the furnace, and the terminal block is used to connect to an external power supply cable.

[0035] Specifically, the introduced electrode 16 is a high-current water-cooled vacuum electrode in the prior art. It is installed on the furnace wall through a fixed base. It mainly introduces the external power supply into the corresponding position of the strip heating component in the furnace through its conductive rod. The conductive rod is equipped with a circulating cooling water channel. Its specific structure is common knowledge and will not be described in detail here.

[0036] The lead-out electrode 14 includes a first inner furnace flange 14-1 located inside the furnace wall, a first outer furnace flange 14-2 located outside the furnace wall, and a first cylinder 14-3 providing driving force. The cylinder seat of the first cylinder 14-3 is fixed to the outer side of the furnace wall by multiple first positioning pins 14-4. The end of its piston rod is connected to a first pull rod 14-5 made of conductive metal. The first pull rod 14-5 passes through the furnace wall and its two ends pass through the inner furnace flange 14-1 and the first outer furnace flange 14-2, respectively. The end of the first pull rod 14-5 located inside the vacuum chamber is provided with external threads and screwed with a first locking nut 14-6. The end located on the atmospheric side, i.e., outside the furnace, is fitted with a metal connecting block 14-7. The connecting block 14-7 has a connecting hole 14-8 to connect the conductive heating circuit inside the furnace to the external power supply cable. Preferably, the first tie rod 14-5 and / or connecting block 14-7 are made of copper, and the first furnace outer flange 14-2 and the first furnace outer flange 14-2 are made of stainless steel.

[0037] Preferably, an internal furnace insulating gasket is sandwiched between the first internal furnace flange 14-1 and the inner side of the furnace wall, and the cross-sectional area of ​​the insulating gasket is larger than the flange surface area of ​​the internal furnace flange 14-1 to increase the creepage distance and achieve reliable insulation isolation. An external furnace insulating gasket is provided between the inner wall of the first external furnace flange 14-2 and the outer wall of the first tie rod 14-5. In order to achieve dynamic vacuum sealing at the penetration point of the first tie rod 14-5, a first bellows 14-11 is sleeved on the outside of the rod body of the first tie rod 14-5 located outside the furnace. One end of the first bellows is sealed and welded to the first external furnace flange 14-2, and the other end is welded to the connecting block 14-7 sleeved on the first tie rod 14-5. The cross-sectional area of ​​the connecting block 14-7 is larger than the cross-sectional area of ​​the first tie rod 14-5, so that the first bellows can expand and contract synchronously with the radial reciprocating movement of the first tie rod 14-5, thereby maintaining a complete vacuum sealing barrier while realizing motion transmission.

[0038] The output end of the inner door electrode 13 can be in the form of a plug-in connection adapted to the fork-shaped joint 12-2 of the touch electrode 12, or it can be fitted onto the first pull rod 14-5 after opening a through hole; the inner door electrode 13 is limited between the first furnace flange 14-1 and the first locking nut 14-6; when the door assembly is closed, the U-shaped groove of the touch electrode 12 is inserted into the first pull rod 14-5 and clamped between the end face of the inner door electrode 13 and the end face of the first locking nut 14-6.

[0039] Since the first pull rod 14-5 generates a lot of heat during the conduction process, it is preferable to open a cooling circulating water channel along the axial direction inside the first pull rod 14-5. The inlet 14-9 and outlet 14-10 of the water channel are both located outside the furnace and are respectively connected to external cooling water pipes to achieve forced cooling of the first pull rod 14-5.

[0040] Based on the above structural description, the conductive process of the lead-out electrode 14 is as follows: The front door assembly 4 and / or the rear door assembly 5 are equipped with limit switches. When a signal that the door is closed in place is detected, the control system sends a command to the first cylinder 14-3, and the first pull rod 14-5 is pulled back towards the outside of the furnace. Then, through the clamping force between the first locking nut 14-6 and the first furnace inner flange 14-1, the inner electrode 13 and the contact electrode 12 are tightly attached to each other, and a stable current conduction path is established.

[0041] Preferably, the intermediate electrode 15 includes a second inner furnace flange 15-1 located inside the furnace wall, a second outer furnace flange 15-2 located outside the furnace wall, and a second cylinder 15-3 providing driving force. The cylinder seat of the second cylinder 15-3 is fixed to the outer side of the furnace wall by a plurality of second positioning pins 15-4, and its piston rod end is connected to a second pull rod 15-5. The other end of the second pull rod 15-5 passes through the second inner furnace flange 15-1, the furnace wall, and the second outer furnace flange 15-2, respectively. The end of the second pull rod 15-5 located inside the vacuum chamber is provided with external threads and screwed with a second locking nut 15-6, while the end located on the atmospheric side, i.e., outside the furnace, is fitted with a third outer furnace flange 15-7. Preferably, the second pull rod 15-5, the second outer furnace flange 15-2, and / or the third outer furnace flange 15-7 are made of stainless steel.

[0042] Preferably, an internal furnace insulating gasket is also sandwiched between the second furnace inner flange 15-1 and the corresponding inner side of the furnace wall, and the cross-sectional area of ​​the insulating gasket is larger than the flange surface area of ​​the second furnace inner flange 15-1. To achieve dynamic vacuum sealing at the penetration point of the second tie rod 15-5, a second bellows is fitted around the outside of the tie rod 15-5 located outside the furnace. One end of the second bellows is sealed and welded to the second furnace outer flange 15-2, and the other end is welded to the radial end face of the third furnace outer flange 15-7. The output end of the corresponding door inner electrode 13 is located above the second tie rod 15-5 and is confined between the second furnace inner flange 15-1 and the second locking nut 15-6. When the front door assembly 4 and / or the rear door assembly 5 are closed, the U-shaped groove of the corresponding contact electrode 12 engages with the second tie rod 15-5 and is clamped between the end face of the door inner electrode 13 and the second locking nut 15-6.

[0043] The conduction process of intermediate electrode 15 and lead-out electrode 14 is the same, and will not be described again here.

[0044] Thus, the current flow path can be described as follows: The current is introduced from the introducing electrode 16, and sequentially flows through the strip heating components on the inner side of one furnace wall, the strip heating components on the inner side of the front door component 4 or the rear door component 5, the strip heating components on the inner side of the other furnace wall, and the strip heating components on the inner side of another door body component, and finally is led out from the leading-out electrode 14 on the same side as the introducing electrode 16, forming a series heating circuit. By stretching the pull rod of the conductive connection structure, the touch electrode 12 and the inner electrode 13 in the door can be connected, making the conduction path short and direct, and there is no need to open any electrode through holes on the door body, ensuring the sealed environment inside the furnace and reducing the complicated use of external cables.

[0045] Preferably, the front door component 4 is configured to be able to act sequentially in two directions to achieve engagement with the conductive connection structure. First, the front door component 4 moves horizontally, and the horizontal movement direction is parallel to the stretching direction of the first cylinder 14-3 or the second cylinder 15-3, so that the fork-shaped engaging portion 12-2 of the touch electrode 12 installed on the inner wall of the front door body reaches a predetermined engaging position where it is radially aligned with the corresponding first pull rod 14-5 or second pull rod 15-5 in terms of spatial position. Subsequently, the front door component 4 moves longitudinally, driving the fork-shaped engaging portion 12-2 of the touch electrode 12 to move towards the furnace interior direction, so that the U-shaped groove of the fork-shaped engaging portion 12-2 is smoothly clamped into the corresponding first pull rod 14-5 or second pull rod 15-5, completing the plugging fit between the touch electrode 12 and the corresponding pull rod.

[0046] Preferably, the rear door component 5 has the same structure as the front door component, or the rear door component 5 is configured to only have the longitudinal movement function. When the rear door component 5 is closed longitudinally, the touch electrode 12 installed on the inner wall of the rear door body directly moves longitudinally with the door body and is plugged into the corresponding conductive connection structure on the furnace wall side at one time to achieve electrical connection. Preferably, the vacuum pump group 17 supporting the furnace is integrally installed on the supporting frame 18 behind the rear door component 5 and moves back and forth with the rear door component 5, solving the problem of cramped space caused by installing the pump group on the side in the traditional vacuum hot pressing furnace.

[0047] The step-by-step movement structure of the above front door component 4 combines the large-stroke horizontal translation of the large-mass door body with the short-range longitudinal forward feeding of electrode plugging. During the horizontal movement stage, the fork-shaped engaging portion 12-2 can be accurately aligned with the first pull rod 14-5 or the second pull rod 15-5, and during the subsequent longitudinal plugging stage, a smooth and impact-free bite is achieved between the U-shaped groove and the corresponding pull rod, effectively protecting the electrode engaging surface and ensuring the reliable establishment of a large-current path. Preferably, the front door component 4 is driven by a dual pneumatic motor configuration, and only 1 air path and 2 solenoid valves are required for control.

[0048] When the upper pressure head assembly 2 and the lower pressure head assembly 3 apply pressure to the workpiece and perform high-temperature diffusion welding, the conductive heating circuit provides continuous and uniform heat to the vacuum hot pressing chamber. During the conductive process, the contact electrode 12, the inner electrode 13, and the conductive connection structure generate temperatures above 1000°C in the furnace due to the large current they carry. The heat is conducted through the joint surfaces to the first and second furnace flanges 14-1 and 15-1 and the furnace wall, and then quickly carried away by the circulating cooling water channels in the furnace wall interlayer. The greater the pulling force provided by the cylinder, the tighter the fit between the joint surfaces, the smaller the joint resistance, and the higher the heat dissipation efficiency, thereby effectively suppressing the overheating deformation of the electrode connection parts.

[0049] Preferably, the inner side of the furnace wall is equipped with two sets of independently controlled and parallel conductive heating circuits, corresponding to the upper and lower heating zones respectively. The appropriate number of circuits can be flexibly activated according to the height of the workpiece being processed. When the workpiece is tall, all conductive heating circuits are activated to ensure uniform temperature in the chamber; when the workpiece is a thin plate, only the conductive heating circuit corresponding to the workpiece area is activated, thereby achieving energy saving and precise temperature control.

[0050] The conductive heating circuits of the upper and lower pressure head assemblies are independent. The upper pressure head assembly 2 also includes two copper pipes 21 disposed within its top frame. The copper pipe 21 connected to the power supply cable is electrically connected to the input end of the first molybdenum strip assembly inside the upper pressure head via a conductor. The output end of the conductive heating element disposed within the upper pressure head is then connected to the other copper pipe 21 connected to the output cable via a conductor, thus forming a complete discharge heating circuit. The lower pressure head assembly 3 also has a conductive heating element disposed inside its lower pressure head, with its input and output ends electrically connected to the input and output cables respectively via conductors.

[0051] Preferably, the conductive heating element is an S-shaped molybdenum strip assembly, and its arrangement in the upper and lower pressure heads is existing technology, which will not be described in detail here.

[0052] Preferably, temperature sensors are provided on the tie rods and / or furnace flanges of all electrodes in this application. To prevent localized overheating or even burnout caused by poor conductive contact, oxidation of the mating surface, insufficient tie rod clamping force, or abnormal cooling system, this application adds a temperature monitoring and protection mechanism to all electrode assemblies involved in the conductive connection structure, including lead-out electrodes, intermediate electrodes, and lead-in electrodes.

[0053] Specifically, one or more contact temperature sensors 23 are installed at the end of the pull rod of each electrode group located outside the furnace, and / or on the surface or inside of the furnace flange, and are electrically connected to the main control system of the equipment. The temperature sensors 23 are used to collect real-time temperature changes of the pull rod and the furnace flange during the conductive and cooling processes. Since the pull rod and the furnace flange directly or indirectly form conductive paths with the contact electrodes inside the furnace and the electrodes inside the door, their temperature can effectively reflect the contact state and heating status of the conductive connection structure. A preset safe temperature threshold is established in the control system. When the temperature detected by any temperature sensor exceeds the corresponding threshold, the control system determines that the electrode contact is overheated or the conductive circuit is abnormal, and immediately cuts off the power supply to the corresponding conductive heating circuit. The vacuum system and cooling system continue to operate to prevent further deterioration due to local heat accumulation. An alarm message is displayed on the human-machine interface clearly indicating the location of the abnormal electrode and the current temperature value, and the restart of the heating circuit is prohibited until the fault is cleared, the temperature returns to a safe range, and the operator manually resets it.

[0054] Furthermore, the temperature sensor signal can be linked with the cooling system. When an abnormal increase in the temperature of the tie rod is detected, the flow rate of the corresponding cooling water circuit can be automatically increased or the backup cooling circuit can be triggered. This solution significantly improves the reliability of the vacuum autoclave without compromising the vacuum seal or adding complexity to the internal structure. Example

[0055] This embodiment provides a method for operating a vacuum autoclave with built-in conductive connections, the steps of which are as follows: S1. Place the workpiece to be processed on the lower pressure head assembly 3, and adjust the upper pressure head assembly 2 to a suitable position; S2. Drive the rear door assembly 5 to move longitudinally to close, so that the contact electrode 12 on the inner wall of the rear door can be directly inserted into the corresponding furnace wall side conductive connection structure to complete the electrical connection. S3. First drive the front door assembly 4 to move laterally into place, then drive the front door assembly 4 to move longitudinally, so that the U-shaped groove of the fork-shaped joint 12-2 smoothly engages the first pull rod 14-5 and the second pull rod 15-5, and complete the insertion. S4. After the limit switch on the front door assembly 4 detects that the door is closed, it sends a signal to the first and second cylinders 14-3 and 15-3, and causes the corresponding pull rod to move out of the furnace. The door inner electrode 13 and the contact electrode 12 are tightly attached by their respective locking nuts to establish a stable current path. S5. Start the vacuum pump group 17 that moves together with the rear door assembly 5 to evacuate the vacuum thermocompression chamber to the required process value; S6. Select to activate one or more groups of parallel conductive heating circuits according to the height of the workpiece; the current is introduced through the introducing electrode 16 and flows through the strip heating components on the inner side of the furnace wall and the inner side of the door body in sequence to form a series heating circuit; at the same time, independently activate the conductive heating circuits inside the upper and lower platen assemblies 2 and 3 to heat the graphite platens. S7. The upper platen assembly 2 moves downward to apply a set pressure to the workpiece, and at the same time, the conductive heating system maintains a high-temperature environment in the chamber for diffusion welding or hot press sintering. S8. After welding is completed, stop heating, and water is passed through the circulating cooling water channels in the furnace wall and the internal circulating cooling water channels of the tie rods to force cooling. After the temperature drops to a safe range, break the vacuum environment in the furnace. S9. The front door assembly 4 first longitudinally withdraws to disconnect the electrodes and then horizontally moves away; the rear door assembly 5 directly opens longitudinally; finally, take out the processed workpiece. Embodiment

[0056] This embodiment introduces the cooling system of the vacuum hot press furnace on the basis of Embodiment 1: The cooling system is respectively arranged on the front door assembly 4, the rear door assembly 5, the furnace body frame 1 and the upper and lower platen assemblies. Specifically, the cooling systems of the front door assembly 4 and the rear door assembly 5 include a first circulating cooling water channel 19 provided on the outer side of the door body of the front door assembly 4 and / or the rear door assembly 5. It is integrally distributed in an S shape or a square shape, and preferably a square shape. Its surrounding positions are opposite to the rectangular sealing rings 22 on the inner side of the front door assembly 4 and / or the rear door assembly 5. On the basis of ensuring that the cooling path is comprehensively covered, it can effectively cool the sealing ring 来 自 爱 开 淘 网 22 and prevent it from deforming due to long-term high temperature.

[0057] The left and right furnace walls are empty inside and are provided with second circulating water channels 20 respectively distributed in an S shape or a square shape. Preferably, the second circulating cooling water channel 20 adopts a square structure with diagonal inlet and outlet for better cooling effect.

[0058] Third circulating cooling water channels are respectively arranged inside the graphite platens of the upper and lower platen assemblies. The third circulating cooling water channels are respectively connected to the inlet and outlet water pipes outside the furnace from the corresponding interfaces.

[0059] Preferably, according to the description of Embodiment 2, water inlet pipes and outlet pipes can be respectively arranged in the two copper pipes 21 of the upper platen assembly 2 and are connected to the third circulating cooling water channel arranged inside the upper platen; according to the area of the upper platen and the cooling requirements of the whole process, multiple groups of circulating cooling water channels can be introduced by adding pipelines at the top of the upper platen assembly 2. Embodiment

[0060] The traditional furnace wall and the bed body frame for support are independent of each other and have gaps. This integrated frame integrates the functions of the bearing bed body and the vacuum furnace shells of the left and right furnace walls and has the ability to withstand large-tonnage pressures.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vacuum autoclave with built-in conductive connection, comprising a furnace frame for creating a vacuum environment, an upper pressure head assembly and a lower pressure head assembly disposed within the vacuum autoclaving chamber, and a conductive heating system and a cooling system integrated within the frame, characterized in that: The furnace frame is a rectangular closed structure with open front and rear ends, and is equipped with a front door assembly and a rear door assembly that can be opened and closed independently. The conductive heating system includes at least three independently controllable conductive heating circuits, two of which are respectively located in the upper pressure head assembly and the lower pressure head assembly, and the remaining circuits are located inside the furnace frame and the front door assembly and the rear door assembly. The conductive heating circuits located on the inner walls of the front and rear door assemblies are connected to touch electrodes at their ends; the conductive heating circuits located on the inner walls of the furnace frame are configured as inner door electrodes. The hot press furnace also includes a conductive connection structure electrically connected to the electrode inside the door. The conductive connection structure is installed on the furnace wall of the furnace body frame and is used to electrically connect the touch electrode to the corresponding electrode inside the door when the front door assembly and / or the rear door assembly are in the closed state, so as to form a complete conductive heating circuit.

2. The vacuum hot press furnace with built-in conductive connection according to claim 1, characterized in that: The conductive connection structure includes an inlet electrode, an outlet electrode, and an intermediate electrode disposed on the left and right furnace walls; the inlet electrode is used to connect the power supply to the furnace; the outlet electrode is used to lead the furnace circuit to the outside; and the intermediate electrode is used to realize the series transition of the furnace circuit without connecting it to the outside of the furnace.

3. The vacuum hot press furnace with built-in conductive connection according to claim 2, characterized in that, The lead-out electrode and the intermediate electrode each include: A cylinder fixed to the outside of the furnace wall; A pull rod that is connected to and driven by the piston rod of the cylinder to reciprocate; An internal flange fixed to the inside of the furnace wall; An external flange fixed to the outside of the furnace wall; the tie rod movably passes through the furnace wall, the internal flange, and the external flange; A locking nut is provided at one end of the pull rod located inside the furnace; the inner electrode of the door is sleeved on the pull rod and is axially limited between the inner flange of the furnace and the locking nut, and the inner electrode of the door has a joint for engaging with a contact electrode on the door assembly; The lead-out electrode has a terminal block at one end outside the furnace, which is used to connect to an external power supply cable.

4. The vacuum hot press furnace with built-in conductive connection according to claim 3, characterized in that: The touch electrode includes a connecting part and a forked joint at its end. The forked joint includes two parallel and spaced-apart branch arms, with a U-shaped groove formed between the two branch arms and a pull rod inserted into it.

5. The vacuum hot press furnace with built-in conductive connection according to claim 2, characterized in that: The lead-in electrode and / or lead-out electrode are provided with an axial circulating cooling water channel.

6. The vacuum hot press furnace with built-in conductive connection according to claim 2, characterized in that: Temperature sensors are provided on the inlet electrode, outlet electrode, and intermediate electrode. The temperature sensors are electrically connected to the control system. The control system has a preset safe temperature threshold and is configured to automatically cut off the power supply of the corresponding conductive heating circuit, keep the cooling system running, and issue an alarm signal when the temperature detected by any temperature sensor exceeds the safe temperature threshold.

7. The vacuum hot press furnace with built-in conductive connection according to claim 3, characterized in that: The front door assembly is configured to move sequentially in two directions: first, it moves laterally, parallel to the cylinder or cylinder extension direction, so that the forked joint of the touch electrode reaches a predetermined engagement position radially aligned with the corresponding pull rod in space; then, it moves longitudinally, driving the forked joint of the touch electrode toward the furnace, so that the U-shaped groove of the forked joint smoothly engages with the corresponding pull rod, completing the insertion and engagement of the touch electrode and the corresponding pull rod, so that the touch electrode and the conductive connection structure are connected. And / or, the rear door assembly has the same structure as the front door assembly, or the rear door assembly is configured to have longitudinal movement capability, such that when closed, the touch electrode is inserted into the corresponding conductive connection structure.

8. The vacuum hot press furnace with built-in conductive connection according to claim 1, characterized in that: The cooling systems are respectively arranged in the front door assembly, the rear door assembly, the furnace frame, and the upper and lower pressure head assemblies.

9. The vacuum hot press furnace with built-in conductive connection according to claim 1, characterized in that: The furnace wall and the supporting bed frame of the furnace body frame are integrated into one piece.

10. A method for operating a vacuum hot press furnace based on any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Place the workpiece to be processed on the lower pressure head assembly; S2: Drive the rear door assembly to move longitudinally to close, so that the contact electrode on its inner wall is connected to the corresponding conductive connection structure; S3: Drive the front door assembly to move laterally first, aligning the touch electrodes on its inner wall with the corresponding conductive connection structure axially; then move longitudinally, so that the touch electrodes and the conductive connection structure are connected. S4: After the limit switch on the front door assembly detects that the door is closed, the drive cylinder moves the pull rod out of the furnace, pressing the contact electrode and the inner electrode of the door together to establish a stable current path. The current flow path is as follows: the current is introduced from an inlet electrode, flows sequentially through the strip heating assembly on the inner side of one furnace wall, the strip heating assembly on the inner side of the front door assembly or the rear door assembly, the strip heating assembly on the inner side of the other furnace wall, and the strip heating assembly on the inner side of another door assembly, and finally exits from the outlet electrode on the same side as the inlet electrode, forming a series heating circuit. S5: Start the vacuum pump unit to evacuate the vacuum thermocompression chamber; S6: Depending on the height of the workpiece, selectively activate one or more sets of conductive heating circuits to heat the furnace. S7: Drive the upper pressure head assembly to apply pressure to the workpiece while maintaining a high temperature environment for diffusion welding or hot pressing sintering. S8: After welding is completed, stop heating, start the cooling system to cool down, and break the vacuum after the temperature drops. S9: Drive the front door assembly to first exit longitudinally and de-energize, then move it laterally; drive the rear door assembly to open longitudinally directly; remove the processed workpiece.

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