An internal furnace door device for a double-layer roller hearth heating furnace

Abstract

This invention relates to the field of heating furnace technology and discloses a built-in furnace door device for a double-layer roller hearth heating furnace, including an upper furnace door device, a lower furnace door device, and a control module. The upper furnace door device includes an upper furnace door body, a servo motor, a drive shaft, a chain drive mechanism, an upper guide groove, and upper rollers. In the closed state, the upper furnace door body is located inside the furnace body and seals the upper furnace opening; in the open state, it opens the upper furnace opening by lifting upwards. The lower furnace door device includes a lower furnace door body, a power drive component, a horizontal moving bracket, and a lifting frame. The lower furnace door body is mounted on the lifting frame. The control module is electrically connected to the servo motor and the power drive component, respectively, and is used to control the coordinated opening and closing of the upper and lower furnace door devices. After the furnace door of this application is closed, it can effectively seal the upper and lower furnace openings, reducing heat loss at the furnace openings, lowering the risk of sheet metal oxidation, and reducing the consumption of protective gas.

Description

Technical Field

[0001] This invention relates to the field of heating furnace technology, and more specifically, to a built-in furnace door device for a double-layer roller hearth heating furnace. Background Technology

[0002] Hot stamping technology is widely used in the manufacturing of high-strength parts. Its process typically includes sheet metal heating, heat preservation and conveying, and die stamping. The heating furnace, as a key piece of equipment in the hot stamping production line, primarily heats the sheet metal to its austenitizing temperature to meet the requirements of subsequent hot forming processes. To improve production efficiency and equipment utilization, existing hot stamping production lines are increasingly adopting a double-layer roller hearth heating furnace structure, achieving continuous heating production through upper and lower conveying channels.

[0003] Most existing heating furnaces use furnace door structures located on the outside of the furnace opening, and the furnace door body typically has a large structural thickness and requires considerable installation space. For roller hearth furnaces in the hot stamping industry, the feeding and discharging ends are usually located close to the loading and unloading platforms, and the furnace opening area needs to maintain a small gap between the furnace rollers to ensure stable conveying of the heated high-temperature sheet material and prevent sagging or even conveying blockage due to excessive span. If a traditional furnace door structure located outside the furnace opening is used, it will not only occupy limited equipment layout space, but also easily force an increase in the gap between the furnace rollers in the furnace opening area, thereby affecting the stability of sheet material conveying.

[0004] Therefore, it is necessary to design a built-in furnace door device for a double-layer roller hearth furnace to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes a built-in furnace door device for a double-layer roller hearth heating furnace, which aims to solve the problem that the existing furnace door structure occupies limited equipment layout space and easily forces the furnace roller spacing in the furnace mouth area to increase, thereby affecting the stability of material conveying.

[0006] This invention proposes a built-in furnace door device for a double-layer roller hearth heating furnace, including an upper furnace door device, a lower furnace door device, and a control module; The upper furnace door device includes an upper furnace door body, a servo motor, a drive shaft, a chain drive mechanism, an upper guide groove, and upper rollers; the servo motor drives the chain drive mechanism through the drive shaft, and the chain drive mechanism is connected to the upper furnace door body; the upper rollers are in rolling cooperation with the upper guide groove; the upper furnace door body is located inside the furnace body and closes the upper furnace opening when closed, and opens the upper furnace opening by lifting it upwards when open; The lower furnace door device includes a lower furnace door body, a power drive component, a horizontal moving support, and a lifting frame; the output end of the power drive component is connected to the horizontal moving support; the lifting frame is in transmission cooperation with the horizontal moving support, and the lower furnace door body is installed on the lifting frame; The control module is electrically connected to the servo motor and the power drive component, respectively, and is used to control the coordinated opening and closing of the upper furnace door device and the lower furnace door device.

[0007] Furthermore, the servo motor is connected to the drive shaft via a coupling, the drive shaft is equipped with a sprocket, and the chain drive mechanism includes a chain, one end of which is fixed to the sprocket and the other end is connected to the upper furnace door body.

[0008] Furthermore, the upper furnace door body is a composite structure comprising a heat-insulating material layer and a heat-resistant steel structure layer, with a fire-facing surface provided with a fire-resistant fiber module and a stainless steel cooling water jacket or heat-insulating baffle on the unfacing surface.

[0009] Furthermore, the lower furnace door device also includes a lower guide wheel; the horizontal moving bracket is provided with a guide rail with a lifting ramp, the bottom of the lifting frame is provided with a lower wheel groove, the lower guide wheel is provided in the lower wheel groove, and the lower guide wheel rolls in cooperation with the lifting ramp of the guide rail.

[0010] Furthermore, the lower furnace door body is constructed or assembled using high-strength heavy refractory bricks.

[0011] Furthermore, the lower furnace door device also includes a bottom support and lower rollers; the horizontal moving support is slidably mounted on the bottom support via the lower rollers; the bottom support is connected to the ground via a screw column structure.

[0012] Furthermore, the power drive component is mounted on the base bracket; the power drive component is a cylinder or a servo electric actuator.

[0013] Furthermore, when controlling the furnace door to open, the control module controls the power drive to lower the lower furnace door body to the bottom limit position; after the descent is completed, the thickness parameter of the conveyed material is obtained, the target opening height is determined based on the thickness parameter, and the control module controls the servo motor to raise the upper furnace door body to the target opening height.

[0014] Furthermore, after the material conveying is completed, the control module controls the servo motor to lower the upper furnace door body to the closed position; after the upper furnace door body is closed, the control module controls the power drive component to raise the lower furnace door body to the closed position.

[0015] Furthermore, when the control module detects the presence of material at the furnace opening during the shutdown process, it triggers an interlock mechanism, interrupts the shutdown command, and controls the upper furnace door and the lower furnace door to open in reverse.

[0016] Compared with existing technologies, the advantages of this invention are as follows: both the upper and lower furnace door devices are located inside the furnace body. When closed, the furnace door body is hidden inside the furnace body, without occupying space outside the furnace body, avoiding interference with the feeding platform, discharging platform, and other auxiliary mechanisms. This makes it suitable for space-constrained conditions such as double-layer roller hearth furnaces. After the furnace doors are closed, they effectively seal the upper and lower furnace openings, reducing heat loss at the furnace openings and decreasing the probability of outside air entering the furnace. This helps maintain the purity of the protective atmosphere inside the furnace, reduces fluctuations in oxygen content, thereby reducing the risk of sheet metal oxidation and minimizing protective gas consumption. By setting the furnace door structure as an upper and lower furnace door device, with the upper furnace door opening by lifting upwards and the lower furnace door opening by sliding downwards, it can match the arrangement of the upper and lower furnace openings of a double-layer roller hearth furnace, solving the problem that traditional external furnace doors cannot meet the requirements of multi-layer roller hearth furnaces. The upper furnace door device achieves lifting and lowering via a servo motor-driven chain transmission mechanism. Combined with the upper guide groove and upper rollers, this ensures smooth operation and accurate positioning of the furnace door. The lower furnace door device uses a power drive component to link the horizontal moving support and lifting frame, achieving smooth lifting and lowering of the furnace door. The control module coordinates the control of the upper and lower furnace doors, making the opening and closing process more reliable. By shortening the furnace opening time, reducing the furnace opening area, and improving the stability of the thermal field and atmosphere inside the furnace, a more stable heating environment can be provided for hot stamping, improving the heating quality of the sheet metal and the consistency of subsequent forming. Attached Figure Description

[0017] 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 invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the built-in furnace door device of the double-layer roller hearth heating furnace provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the upper furnace door device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the furnace door device provided in an embodiment of the present invention.

[0018] The components include: 1. Upper furnace door device; 11. Upper furnace door body; 12. Servo motor; 13. Drive shaft; 14. Chain drive mechanism; 15. Upper guide groove; 16. Upper roller; 17. Coupling; 18. Sprocket; 2. Lower furnace door device; 21. Lower furnace door body; 22. Power drive component; 23. Horizontal moving support; 24. Lifting frame; 25. Lower wheel groove; 26. Lower guide wheel; 27. Bottom support; 28. Lower roller; 29. ​​Screw column structure; 3. Control module; 4. Double-layer roller hearth heating furnace. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] In some embodiments of this application, see Figure 1-3 As shown, a built-in furnace door device for a double-layer roller hearth heating furnace is proposed. The double-layer roller hearth heating furnace 4 is equipped with a built-in furnace door device, including an upper furnace door device 1, a lower furnace door device 2, and a control module 3. The upper furnace door device 1 and the lower furnace door device 2 are respectively located at the upper furnace opening and the lower furnace opening of the double-layer roller hearth heating furnace 4, and are both arranged inside the furnace body to realize the opening and closing control of the furnace opening.

[0021] The upper furnace door device 1 includes an upper furnace door body 11, a servo motor 12, a drive shaft 13, a chain drive mechanism 14, an upper guide groove 15, and an upper roller 16; the servo motor 12 drives the chain drive mechanism 14 through the drive shaft 13, and the chain drive mechanism 14 is connected to the upper furnace door body 11; the upper roller 16 is in rolling engagement with the upper guide groove 15; the upper furnace door body 11 is located inside the furnace body and closes the upper furnace opening when closed, and opens the upper furnace opening by lifting it upwards when open; The lower furnace door device 2 includes a lower furnace door body 21, a power drive component 22, a horizontal moving support 23, and a lifting frame 24; the output end of the power drive component 22 is connected to the horizontal moving support 23; the lifting frame 24 is in transmission cooperation with the horizontal moving support 23, and the lower furnace door body 21 is installed on the lifting frame 24; The control module 3 is electrically connected to the servo motor 12 and the power drive component 22 respectively, and is used to control the coordinated opening and closing of the upper furnace door device 1 and the lower furnace door device 2.

[0022] In this embodiment, the upper furnace door device 1 is located at the corresponding position of the upper furnace opening of the double-layer roller hearth heating furnace 4 and is integrally arranged inside the furnace body to realize the opening and closing control of the upper furnace opening. The upper furnace door device 1 includes an upper furnace door body 11, a servo motor 12, a drive shaft 13, a chain drive mechanism 14, an upper guide groove 15, and an upper roller 16.

[0023] The servo motor 12 is installed as a power source in a fixed position on the furnace body structure or frame, and its output end is connected to the drive shaft 13 through a coupling 17 to achieve stable power transmission. The drive shaft 13 is arranged horizontally or vertically along the furnace body, and a sprocket 18 is fixedly installed at one end or in the middle of it to cooperate with the chain drive mechanism 14 to form a transmission relationship.

[0024] The chain drive mechanism 14 includes a chain structure, with the chain wound around the sprocket 18 to form a closed loop or traction transmission path. One end of the chain is fixedly connected to the sprocket 18 and generates cyclic motion as the sprocket 18 rotates, while the other end is connected to the upper furnace door body 11.

[0025] When the servo motor 12 starts, its output torque is transmitted to the drive shaft 13 via the coupling 17. The drive shaft 13 drives the sprocket 18 to rotate synchronously, thereby causing the chain to shift and exert an upward or downward traction force on the upper furnace door body 11, thus realizing the lifting and lowering movement of the upper furnace door body 11. During this process, when the upper furnace door body 11 moves vertically, the upper rollers 16 on both sides of it always maintain rolling contact with the upper guide grooves 15 located inside the walls on both sides of the furnace body. The upper guide grooves 15 form a trajectory constraint on the upper rollers 16, ensuring that the upper furnace door body 11 moves only along a preset vertical path, avoiding lateral deviation, tilting, or jamming, thereby ensuring the stability and sealing accuracy of the furnace door opening and closing process.

[0026] The upper furnace door body 11 is a composite structure, including an insulation material layer and a heat-resistant steel structure layer. The insulation material layer is used to reduce the conduction of high temperature inside the furnace to the outside and improve the heat insulation performance; the heat-resistant steel structure layer is used to provide overall mechanical strength, so that the upper furnace door body 11 can maintain structural stability under high temperature environment and frequent opening and closing conditions.

[0027] In a further embodiment, a refractory fiber module is provided on the fire-facing surface of the upper furnace door body 11. This refractory fiber module is used to directly withstand the high-temperature radiant heat inside the furnace, improve the thermal shock resistance, and further enhance the heat insulation effect.

[0028] A stainless steel cooling water jacket or heat insulation baffle structure is installed on the back-fired side of the upper furnace door body 11. The cooling water jacket is used to remove some heat through circulating cooling medium to reduce the temperature of the back-fired side; the heat insulation baffle is used to further block the heat conduction path, thereby protecting the external structure of the furnace body and the drive components.

[0029] In the closed state, the upper furnace door body 11 is located inside the furnace body and seals the upper furnace opening, creating a relatively enclosed high-temperature working environment in the upper space of the furnace body, thereby reducing heat leakage and the entry of outside air. In the open state, the servo motor 12 drives the chain transmission mechanism 14 to move, causing the upper furnace door body 11 to rise upward along the trajectory defined by the upper guide groove 15, thereby gradually opening the upper furnace opening to meet the needs of material loading / unloading or process material changeover. Because the upper furnace door body 11 adopts a built-in structure, its movement is completed inside the furnace body during opening and closing, without occupying external space of the furnace body, thus avoiding interference with the feeding platform or discharging platform.

[0030] In this embodiment, the lower furnace door device 2 is located at the corresponding position of the lower furnace opening of the double-layer roller hearth heating furnace 4 and is integrally arranged inside the furnace body to realize the opening and closing control of the lower furnace opening. The lower furnace door device 2 includes a lower furnace door body 21, a power drive component 22, a horizontal moving support 23, and a lifting frame 24.

[0031] The power drive component 22 serves as the power source, with its output end connected to the horizontal moving bracket 23, driving the horizontal moving bracket 23 to reciprocate in the horizontal direction. The power drive component 22 can be selected from cylinders or servo electric actuators depending on the actual working conditions to provide stable linear driving force.

[0032] A linkage structure is provided between the horizontal moving support 23 and the lifting frame 24, enabling the horizontal moving support 23 to drive the lifting frame 24 to produce vertical lifting motion during horizontal movement, thereby realizing the opening and closing action of the lower furnace door body 21. The lower furnace door body 21 is installed on the lifting frame 24 and moves synchronously with the lifting frame 24, used to close or open the lower furnace opening.

[0033] In one embodiment, the lower furnace door device 2 further includes a lower guide wheel 26. A guide rail with a lifting ramp is provided on the horizontal moving support 23. This guide rail can be an inclined guide surface or a ramp guide structure, used to achieve changes in the direction of movement. A lower wheel groove 25 is provided at the bottom of the lifting frame 24, and the lower guide wheel 26 is installed in the lower wheel groove 25, with the lower guide wheel 26 rolling in cooperation with the lifting ramp of the guide rail.

[0034] When the power drive component 22 pushes the horizontal moving bracket 23 to move horizontally, the lower guide wheel 26 rolls along the inclined surface of the guide rail. Due to the change in the height of the inclined surface, the lifting frame 24 generates a vertical lifting displacement while moving horizontally, thus realizing the conversion from horizontal to vertical movement. With this structure, the lifting action of the furnace door can be realized in a limited space, and it has the advantages of compact structure, clear transmission path and high reliability.

[0035] The lower furnace door body 21 is constructed or assembled from high-strength heavy refractory bricks. This structure exhibits excellent heat resistance and deformation resistance under high-temperature environments, enabling it to withstand long-term high-temperature radiation and thermal shock within the furnace, while ensuring the airtightness of the furnace door when closed and reducing heat loss from the furnace opening. Due to its masonry or assembly structure, the lower furnace door body 21 also possesses a degree of maintainability and modular replacement capability, facilitating future maintenance or partial replacement.

[0036] In another embodiment, the lower furnace door device 2 also includes a bottom support 27 and a lower roller 28 structure.

[0037] The horizontal moving support 23 is slidably mounted on the base support 27 via the lower roller 28, enabling the horizontal moving support 23 to achieve stable linear movement on the base support 27, reducing motion friction resistance, and improving operational stability. The base support 27 is connected to the ground via a screw column structure 29, which is used to adjust and position the installation height of the base support 27, allowing the lower furnace door device 2 to adapt to different installation conditions and furnace height differences.

[0038] The power drive component 22 is mounted on the base bracket 27, integrating the drive source with the overall support structure to improve structural compactness and stability. In a preferred embodiment, the power drive component 22 is a cylinder or a servo electric actuator, wherein: when a cylinder is used, rapid opening and closing actions are achieved through pneumatic control; when a servo electric actuator is used, higher precision position control and operational stability are achieved through electronic control.

[0039] During operation, when the lower furnace opening needs to be opened, the power drive unit 22 first drives the horizontal moving support 23 to move horizontally. During this movement, the lower guide wheel 26 rolls along the inclined surface of the guide rail, causing the lifting frame 24 to gradually descend, thereby lowering the lower furnace door body 21 to the open position, forming the lower furnace opening channel. When the furnace opening needs to be closed, the power drive unit 22 drives the horizontal moving support 23 to move in the opposite direction, and the lower guide wheel 26 moves in the opposite direction along the inclined surface, causing the lifting frame 24 to gradually rise, thereby driving the lower furnace door body 21 back to the closed position, thus closing the lower furnace opening.

[0040] In this embodiment, the control module 3 is electrically connected to the servo motor 12 and the power drive component 22, respectively, to realize the coordinated opening and closing control between the upper furnace door device 1 and the lower furnace door device 2. The control module 3 can be an industrial controller, a PLC control unit, or an embedded control system, and it has a pre-set furnace door opening and closing control program to receive sensor signals, perform logical judgments, and output control commands.

[0041] During the furnace door opening process, control module 3 executes the coordinated control process according to a preset sequence. First, control module 3 sends an opening command to the power drive component 22, driving the power drive component 22 to move, causing the horizontal moving bracket 23 to move the lower furnace door body 21 downwards until it reaches the bottom limit position. During this process, control module 3 can detect the position status of the lower furnace door body 21 through limit switches, position sensors, or current feedback. When it is detected that the lower furnace door body 21 has completed its descent and is in the limit opening position, control module 3 determines that the lower furnace opening is fully open.

[0042] Subsequently, control module 3 acquires the thickness parameters of the conveyed material. The thickness parameters can be obtained from upstream detection equipment, such as sheet metal thickness sensors, vision recognition systems, or production process databases. After obtaining the thickness parameters, control module 3 determines the target opening height according to a preset algorithm. Specifically, while ensuring a safe clearance for material passage, the opening height of the upper furnace door body 11 is limited to the minimum safe opening height that matches the material thickness, in order to reduce the exposed area of ​​the furnace opening.

[0043] Subsequently, the control module 3 outputs a control signal to the servo motor 12, causing the servo motor 12 to drive the drive shaft 13 and the chain transmission mechanism 14 to move, thereby lifting the upper furnace door body 11 upward to the target opening height position and completing the opening of the upper furnace opening.

[0044] After material conveying is completed, control module 3 enters the closing control process. First, control module 3 controls servo motor 12 to move the upper furnace door body 11 downwards along the upper guide groove 15, gradually returning to the closed position and completely closing the upper furnace opening. During the descent of the upper furnace door body 11, the upper roller 16 rolls within the upper guide groove 15 to ensure stability and positioning accuracy during the descent. When control module 3 detects that the upper furnace door body 11 has reached the closed position (e.g., confirmed by limit switch or encoder feedback), control module 3 sends a control command to power drive component 22 to raise and reset the lower furnace door body 21. Power drive component 22 drives horizontal moving bracket 23 to move, causing lifting frame 24 to gradually raise the lower furnace door body 21 to the closed position, thus completing the closure of the lower furnace opening. This sequential control method avoids mechanical interference caused by simultaneous movement of the upper and lower furnace doors, improving operational safety and reliability.

[0045] During the shutdown process, control module 3 is equipped with an interlock protection mechanism. When control module 3 detects material in the furnace opening area, it indicates that the material has not completely passed through or there is a risk of jamming. At this time, control module 3 immediately triggers the interlock logic. After the interlock logic is executed, control module 3 interrupts the current shutdown command and prohibits the continued execution of the furnace door closing action. At the same time, to prevent material from being clamped or equipment damage, control module 3 controls the upper furnace door body 11 and the lower furnace door body 21 to perform reverse opening actions, so that the furnace opening returns to a safe passage state to ensure the safety of material conveying.

[0046] Through the above control methods, this embodiment forms a phased opening and closing strategy for coordinated control of the upper and lower furnace doors. Its core is: the lower furnace door moves first, followed by the upper furnace door (opening phase); the upper furnace door moves first, followed by the lower furnace door (closing phase); the upper and lower furnace doors are interlocked to avoid synchronous conflicts; the opening of the upper furnace door is adaptively adjusted based on the material thickness; and closed-loop control is achieved through state feedback to improve positioning accuracy.

[0047] In summary, both the upper and lower furnace door devices are located inside the furnace body. When closed, the furnace door itself is hidden within the furnace body, not occupying external space and avoiding interference with the feeding platform, discharging platform, and other auxiliary mechanisms. This design is suitable for space-constrained conditions such as double-layer roller hearth furnaces. After closing, the furnace doors effectively seal the upper and lower furnace openings, reducing heat loss at the openings and decreasing the probability of outside air entering the furnace. This helps maintain the purity of the protective atmosphere inside the furnace, reduces fluctuations in oxygen content, and thus lowers the risk of sheet metal oxidation and reduces protective gas consumption. By configuring the furnace door structure as an upper and lower furnace door device, with the upper door opening by lifting upwards and the lower door opening by sliding downwards, it matches the upper and lower furnace opening arrangement of the double-layer roller hearth furnace, solving the problem that traditional external furnace doors cannot meet the requirements of multi-layer roller hearth furnaces. The upper furnace door device achieves lifting and lowering via a servo motor-driven chain transmission mechanism. Combined with the upper guide groove and upper rollers, this ensures smooth operation and accurate positioning of the furnace door. The lower furnace door device uses a power drive component to link the horizontal moving support and lifting frame, achieving smooth lifting and lowering of the furnace door. The control module coordinates the control of the upper and lower furnace doors, making the opening and closing process more reliable. By shortening the furnace opening time, reducing the furnace opening area, and improving the stability of the thermal field and atmosphere inside the furnace, a more stable heating environment can be provided for hot stamping, improving the heating quality of the sheet metal and the consistency of subsequent forming.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A built-in furnace door device for a double-layer roller hearth heating furnace, characterized in that, Includes upper furnace door assembly, lower furnace door assembly, and control module; The upper furnace door device includes an upper furnace door body, a servo motor, a drive shaft, a chain drive mechanism, an upper guide groove, and upper rollers; the servo motor drives the chain drive mechanism through the drive shaft, and the chain drive mechanism is connected to the upper furnace door body; the upper rollers are in rolling cooperation with the upper guide groove; the upper furnace door body is located inside the furnace body and closes the upper furnace opening when closed, and opens the upper furnace opening by lifting it upwards when open; The lower furnace door device includes a lower furnace door body, a power drive component, a horizontal moving support, and a lifting frame; the output end of the power drive component is connected to the horizontal moving support; the lifting frame is in transmission cooperation with the horizontal moving support, and the lower furnace door body is installed on the lifting frame; The control module is electrically connected to the servo motor and the power drive component, respectively, and is used to control the coordinated opening and closing of the upper furnace door device and the lower furnace door device.

2. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, The servo motor is connected to the drive shaft via a coupling. The drive shaft is equipped with a sprocket. The chain drive mechanism includes a chain, one end of which is fixed to the sprocket, and the other end is connected to the upper furnace door body.

3. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, The upper furnace door body is a composite structure comprising a heat-insulating material layer and a heat-resistant steel structure layer. Its fire-facing side is provided with a fire-resistant fiber module, and its unfire-facing side is provided with a stainless steel cooling water jacket or heat-insulating baffle.

4. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, The lower furnace door device also includes a lower guide wheel; the horizontal moving bracket is provided with a guide rail with a lifting ramp, the bottom of the lifting frame is provided with a lower wheel groove, the lower guide wheel is provided in the lower wheel groove, and the lower guide wheel rolls in cooperation with the lifting ramp of the guide rail.

5. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, The lower furnace door body is constructed or assembled from high-strength heavy refractory bricks.

6. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, The lower furnace door device also includes a bottom support and lower rollers; the horizontally movable support is slidably mounted on the bottom support via the lower rollers; the bottom support is connected to the ground via a screw rod column structure.

7. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 6, characterized in that, The power drive component is mounted on the base bracket; the power drive component is a cylinder or a servo electric push rod.

8. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 1, characterized in that, When the furnace door is opened, the control module controls the power drive to lower the lower furnace door body to the bottom limit position; after the descent is completed, the thickness parameter of the conveyed material is obtained, the target opening height is determined based on the thickness parameter, and the control module controls the servo motor to raise the upper furnace door body to the target opening height.

9. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 8, characterized in that, After the material conveying is completed, the control module controls the servo motor to lower the upper furnace door body to the closed position; after the upper furnace door body is closed, the control module controls the power drive unit to raise the lower furnace door body to the closed position.

10. The built-in furnace door device of the double-layer roller hearth heating furnace according to claim 9, characterized in that, When the control module detects the presence of material at the furnace opening during the shutdown process, it triggers an interlock mechanism, interrupts the shutdown command, and controls the upper furnace door and lower furnace door to open in reverse.

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