A multilayer thermal barrier shield for metal heat treatment

Abstract

The utility model discloses a multilayer heat insulation protection device for metal heat treatment, it includes inner layer protection casing, intermediate heat insulation layer group, outer layer heat dissipation casing and interlayer heat conduction adjusting structure. The inner layer casing inner surface is equipped with the corrugated concave -convex structure and the anti -radiation coating, the intermediate layer is by nanometer air gel felt layer, vacuum micropore ceramic plate layer and fills the metal honeycomb sandwich layer of phase change microcapsule, and the outer layer casing is equipped with heat conduction fin and heat dissipation fin, and the cooperation flow guide cover forms the airway, and the interlayer is equipped with heat pipe assembly and adjustable heat insulation baffle. The present application can realize multiform heat insulation and heat dissipation regulation and control.

Description

Technical Field

[0001] This utility model relates to the field of heat insulation and protection structures for metal heat treatment equipment, and in particular to a multi-layer heat insulation and protection device for metal heat treatment. Background Technology

[0002] Metal heat treatment is an important process that alters the microstructure and properties of metallic materials through heating, holding, and cooling. It has wide applications in machinery manufacturing, aerospace, and the automotive industry. During heat treatment, to prevent the high temperatures from affecting surrounding equipment and operators, thermal insulation devices are typically installed outside the heating equipment to reduce heat loss and ensure operational safety. Existing thermal insulation devices often employ a single insulating material or a simple multi-layered structure, suppressing heat through thermal conduction. However, when these devices operate under prolonged high-temperature conditions, localized increases in the outer surface temperature can still occur. The heat transfer path between material layers is relatively direct, leaving room for improvement in overall insulation performance, especially under conditions requiring frequent start-stop cycles or large temperature gradients, where the stability of thermal protection performance needs to be enhanced. Utility Model Content

[0003] The purpose of this utility model is to provide a multi-layer heat insulation and protection device for metal heat treatment, which solves the problems mentioned in the background art.

[0004] This invention is implemented as follows: a multi-layer heat insulation and protection device for metal heat treatment includes an inner protective shell, a middle heat insulation layer group, an outer heat dissipation shell, and an interlayer heat conduction adjustment structure. The inner protective shell is closely attached to the outer wall of the heating equipment and is made of a high-temperature resistant metal alloy. Its inner surface has a corrugated uneven structure, which extends spirally along the circumference. The spacing between adjacent peaks and troughs is of medium scale. The surface of the corrugated uneven structure is coated with a ceramic-based anti-radiation coating, which is formed by sintering a mixture of zirconium oxide and titanium dioxide in a specific ratio and possesses high reflectivity to infrared thermal radiation. The end edges of the inner protective shell are folded outward to form an annular connecting flange. Multiple sets of threaded holes are evenly provided on the annular connecting flange for fixed connection with an external support frame.

[0005] The intermediate heat insulation layer consists of three layers of heat insulation materials with different properties, from the inside out: a nano-aerogel felt layer, a vacuum microporous ceramic plate layer, and a metal honeycomb sandwich layer. The nano-aerogel felt layer is directly attached to the outer surface of the inner protective shell, with a medium thickness and extremely low thermal conductivity, effectively suppressing heat conduction. The vacuum microporous ceramic plate layer is disposed on the outside of the nano-aerogel felt layer, containing a large number of closed micron-sized pores. The pores are under negative pressure, further blocking the gas convection heat transfer path. The two sides of the vacuum microporous ceramic plate layer... All surfaces are coated with a metallized layer, which is an aluminum-nickel alloy sputtered layer, to enhance the heat reflectivity of the surface. The metal honeycomb sandwich layer is located on the outermost side and is composed of a tightly arranged array of hexagonal cross-section metal tubes. The axis of the metal tubes is perpendicular to the shell surface, and the tube wall thickness is uniform. The inner cavity of the metal tubes is filled with phase change microcapsule particles. The phase change temperature range of the phase change microcapsule particles is set within the common operating temperature fluctuation range of the equipment. When the external heat flow fluctuates, the microcapsules undergo a solid-liquid phase change to absorb or release latent heat, thereby smoothing the rate of temperature change.

[0006] The outer heat dissipation shell is fitted over the metal honeycomb sandwich layer. Its main body is a double-layer hollow structure, including an outer metal plate and an inner supporting mesh plate, with an annular cavity between them. Multiple sets of radial heat-conducting fins are arranged in the annular cavity. The heat-conducting fins are made of copper alloy and are stamped and fixed at one end to the inner supporting mesh plate, while the other end extends to a position close to the outer metal plate but does not contact it. The outer surface of the outer metal plate is provided with an axially extending array of heat dissipation fins. The heat dissipation fins have a trapezoidal cross section, and the height gradually decreases from bottom to top to adapt to the boundary layer development law of natural convection airflow. The top of the outer heat dissipation shell is provided with a closed top cover. A small vent hole is opened in the center of the top cover. The diameter of the hole is controlled within a specific range to allow a small amount of air to slowly enter and exit to balance the internal and external air pressure, while preventing a large amount of external dust from entering.

[0007] The interlayer thermal conductivity adjustment structure is disposed between the layers of the intermediate heat insulation layer group to dynamically adjust the interlayer thermal resistance distribution. It includes multiple sets of embedded heat pipe assemblies and a heat flow path switching mechanism. The heat pipe assemblies are uniformly distributed circumferentially, with each heat pipe having a U-shaped bend. Both ends are embedded within a vacuum microporous ceramic plate layer and a metal honeycomb sandwich layer, respectively, while the middle section passes through and is tightly bonded to a nano-aerogel felt layer. After evacuation, the heat pipes are filled with a suitable amount of working fluid, which is a Freon-based cryogenic medium capable of generating heat under temperature gradient drive. Rapid lateral migration; the heat flow path switching mechanism includes multiple rotatable heat-conducting baffles, which are installed in the gap between the metal honeycomb sandwich layer and the outer heat dissipation shell. Each heat-conducting baffle is connected to the shell via a rotating shaft, one end of which extends to the outside of the outer heat dissipation shell and is connected to a manual adjustment knob. The baffle is made of highly thermally conductive graphite material and can selectively overlap the end of the metal honeycomb sandwich layer or detach from it during rotation, thereby controlling whether heat is directly conducted to the outer shell through the baffle.

[0008] Furthermore, an elastic buffer gasket is provided between the inner protective shell and the intermediate heat insulation layer. The buffer gasket is molded from high-temperature silicone rubber and is continuously arranged in the circumferential direction to absorb the stress caused by the difference in thermal expansion and prevent the heat insulation material from cracking and falling off. The cross-section of the buffer gasket is trapezoidal, with the two inclined surfaces on both sides fitting against the surface of the adjacent shell, and an annular protrusion at the bottom that is embedded in the corresponding groove on the outer surface of the inner protective shell to achieve circumferential positioning.

[0009] The bottom of the outer heat dissipation shell is provided with an annular dust collection groove with the opening facing upwards. The dust collection groove is located at the root area of ​​the heat dissipation fin array and is used to collect dust particles that settle in the air to prevent them from accumulating and affecting heat dissipation efficiency. The bottom of the dust collection groove is provided with a small drain hole that slopes downwards to the outside, making it easy to clean the accumulated dust regularly.

[0010] The outer periphery of the metal honeycomb sandwich layer is provided with an annular air guide shroud. A uniform gap is maintained between the air guide shroud and the outer heat dissipation shell to form an annular ventilation channel. The lower part of the air guide shroud is provided with an air inlet cut and the upper part is provided with an air outlet guide slope to guide the external air to flow from bottom to top across the surface of the heat dissipation fins, thereby enhancing the natural convection heat transfer effect.

[0011] This utility model provides a multi-layer heat insulation and protection device for metal heat treatment, which has the following beneficial effects: The device significantly increases the reflectivity of thermal radiation and extends the heat conduction path through the synergistic effect of the corrugated concave-convex structure on the inner protective shell and the anti-radiation coating; the middle heat insulation layer adopts a composite design of nano-aerogel, vacuum ceramic plate and metal honeycomb structure containing phase change material, which achieves comprehensive suppression of heat transfer modes of conduction, convection and radiation; the heat pipe assembly set between the layers can quickly disperse the locally accumulated heat to the circumferential area to avoid hot spot concentration; the adjustable design of the heat conduction baffle allows the direct heat conduction path to be cut off during the high load operation of the equipment, and can be opened during the cooling stage to accelerate heat dissipation; the outer heat dissipation shell combined with the air guide and stepped fins optimizes the airflow pattern and improves the passive heat dissipation capacity; the overall structure can maintain stable heat insulation performance after multiple temperature cycles, effectively reducing the maximum temperature of the outer surface and improving the safety of the working environment. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Figure 2 This is a cross-sectional view of the present invention;

[0014] Figure 3 This is a partially enlarged schematic diagram of the present invention;

[0015] Figure 4 This is a schematic diagram of the installation of the inner protective shell in this utility model.

[0016] Explanation of reference numerals in the attached figures:

[0017] 1. Inner protective shell; 2. Corrugated uneven structure; 3. Anti-radiation coating; 4. Annular connecting flange; 5. Threaded hole; 6. Intermediate heat insulation layer assembly; 7. Nano-aerogel felt layer; 8. Vacuum microporous ceramic plate layer; 9. Metallized coating; 10. Metal honeycomb sandwich layer; 11. Phase change microcapsule particles; 12. Outer heat dissipation shell; 13. Outer metal plate; 14. Inner support mesh plate; 15. Annular cavity; 16. 17. Heat dissipation fins; 18. Top cover; 19. Vent hole; 20. Elastic buffer gasket; 21. Air guide shroud; 22. Air inlet cut; 23. Air outlet guide slope; 24. Annular ventilation duct; 25. Heat pipe assembly; 26. Working fluid; 27. Heat conduction baffle; 28. Shaft; 29. ​​Manual adjustment knob; 30. Dust collection tank; 31. Drain hole; 32. Connecting flange groove; 33. Positioning protrusion. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figures 1 to 4 This utility model provides a multi-layer heat insulation protection device for metal heat treatment. This device is suitable for working environments with continuous high heat flux radiation and periodic temperature changes, such as high-temperature industrial furnaces, heating furnace chambers, or induction heating equipment. Through a multi-level composite structure design, the device achieves three-dimensional blocking and dynamic adjustment of the heat transfer path, improving the stability and adaptability of the overall heat protection performance.

[0020] like Figure 1 As shown, this utility model includes an inner protective shell 1, a middle heat insulation layer group 6, an outer heat dissipation shell 12, and an interlayer heat conduction adjustment structure. Each part is sequentially fitted and fixed from the inside out, forming a complete cylindrical or polygonal closed structure. The entire structure extends axially and surrounds the outer wall of the protected equipment. The inner protective shell 1 is an integral high-temperature resistant alloy component, made of nickel-based high-temperature alloy GH3030 through a spin forming process, possessing good high-temperature strength and oxidation resistance. The inner surface of the inner protective shell 1 is provided with a corrugated uneven structure 2, which is distributed in a continuous spiral pattern with a pitch of 35 mm and a height difference of 8 mm between the crests and troughs, forming a sawtooth undulating profile between adjacent crests and troughs. The surface of the corrugated uneven structure 2 is covered with an anti-radiation coating 3, which is applied by plasma spraying and has a thickness of 0.15 mm. It is formed by sintering a mixture of zirconium oxide and titanium dioxide at a mass ratio of 7:3 at high temperature and has a reflectivity of more than 92% for mid-infrared radiation with a wavelength range of 2 to 5 micrometers.

[0021] The inner protective shell 1 has annular connecting flanges 4 at both ends. These flanges are formed by folding outwards at a 90-degree angle from the shell end, with a fold width of 25 mm. Twelve sets of threaded holes 5 are evenly distributed on each flange, with a center-to-center spacing of 60 mm, circumferentially distributed at equal angles. These holes are used to fix the entire heat insulation device to the external support frame with high-strength stainless steel bolts. The outer surface of the inner protective shell 1 has an annular groove located near the center, with a depth of 3 mm, for embedding an elastic buffer gasket 20. The elastic buffer gasket 20 is molded from modified silicone rubber material, maintaining good resilience at 250 degrees Celsius. Its cross-section is trapezoidal, with both beveled sides fitting against the inner protective shell 1 and the nano-aerogel felt layer 7. A positioning protrusion 33 is located at the center of the bottom, embedding into the connecting flange groove 32 on the outer surface of the inner protective shell 1 to achieve circumferential positioning and prevent the buffer gasket from twisting or shifting during assembly.

[0022] The intermediate heat insulation layer 6 is closely attached to the outside of the elastic buffer gasket 20 and is composed of three layers of heat insulation materials with different functions. From the inside to the outside, they are a nano-aerogel felt layer 7, a vacuum microporous ceramic plate layer 8, and a metal honeycomb sandwich layer 10. The nano-aerogel felt layer 7 is 20 mm thick, with silica nanofibers as the skeleton, an internal porosity greater than 95%, an average pore size of less than 50 nanometers, and a thermal conductivity of less than 0.018 W / m Kelvin at room temperature. The nano-aerogel felt layer 7 is a flexible roll material, which is cut on-site and wrapped around the outer perimeter of the elastic buffer gasket 20, and then bound and fixed with high-temperature resistant metal wire to ensure full contact with the outer surface of the inner protective shell 1.

[0023] The vacuum microporous ceramic plate layer 8 is disposed on the outside of the nano-aerogel felt layer 7, with a thickness of 15 mm. It is made of alumina-based ceramic material through high-temperature foaming and vacuum treatment, and contains a large number of closed micron-sized pores with pore sizes concentrated between 1 and 10 micrometers. The entire plate is under negative pressure, with residual gas pressure below 1 kPa, effectively suppressing heat transfer through collisions between gas molecules. Both main surfaces of the vacuum microporous ceramic plate layer 8 are provided with a metallized coating layer 9. The metallized coating layer 9 is deposited using a magnetron sputtering process to form an aluminum-nickel alloy thin film with a thickness of 2 micrometers and a surface emissivity of less than 0.15, which can reflect most of the heat radiation from the inside back.

[0024] The outermost metal honeycomb sandwich layer 10 is 30 mm thick and consists of multiple tightly arranged hexagonal stainless steel tubes, each with a side length of 6 mm and a wall thickness of 0.3 mm. The axial direction is perpendicular to the shell surface. The metal tubes are filled with phase change microcapsule particles 11, with a particle size of 100 to 200 micrometers. The core material is a paraffin-based organic compound, and the phase change temperature range is set between 180 and 220 degrees Celsius, with a latent heat of phase change of 180 kJ / kg. When external heat flow fluctuations cause a local temperature rise into the phase change range, the microcapsule particles absorb heat and undergo a solid-liquid transition; when the temperature drops, they release heat and re-solidify, thereby slowing down the rate of temperature change and maintaining system thermal equilibrium.

[0025] like Figure 2 As shown, the interlayer thermal conductivity adjustment structure is disposed between the layers of the intermediate heat insulation layer group 6 to regulate the heat distribution in different areas. The structure includes multiple sets of heat pipe assemblies 25 and thermally conductive baffles 27. Each set of heat pipe assemblies 25 is evenly arranged circumferentially, with a total of eight sets, and the included angle between adjacent sets is 45 degrees. The heat pipe assembly 25 has a U-shaped bending structure with a total length of 400 mm. Both ends are inserted into the pre-reserved mounting holes inside the vacuum microporous ceramic plate layer 8 and the metal honeycomb sandwich layer 10, respectively, with an insertion depth of 25 mm. The straight section in the middle passes through the nano-aerogel felt layer 7 and is tightly attached to it. The tube body of the heat pipe assembly 25 is made of copper alloy with an inner diameter of 6 mm and an outer diameter of 8 mm. After cleaning and drying, the inside is evacuated to the level of 10⁻³ Pa and then filled with working fluid 26, which is R134a refrigerant, with a charging amount of 15 grams per heat pipe. Driven by the temperature difference, the working fluid 26 absorbs heat and vaporizes in the evaporation section, the vapor flows to the condensation section and releases heat to liquefy, and the liquid flows back through the capillary wick, completing the rapid lateral heat transfer.

[0026] The heat-conducting baffles 27 are disposed in the annular gap between the metal honeycomb sandwich layer 10 and the outer heat dissipation shell 12, with a total of six baffles equidistantly distributed along the circumference. Each heat-conducting baffle 27 is a fan-shaped thin plate with an arc length corresponding to a central angle of 50 degrees, a radial width of 40 mm, and a thickness of 2 mm. It is made of high thermal conductivity artificial graphite material with a thermal conductivity of not less than 400 watts per meter Kelvin. The heat-conducting baffles 27 are connected to the outer heat dissipation shell 12 via a rotating shaft 28. The rotating shaft 28 penetrates the side wall of the outer heat dissipation shell 12, with one end extending into the interior and welded to the heat-conducting baffle 27, and the other end extending out of the shell and connected to a manual adjustment knob 29. The manual adjustment knob 29 is a circular knob with a graduated pointer, with a rotation angle range of 0 to 90 degrees, corresponding to switching the heat-conducting baffle 27 between a "suspended" position parallel to the shell axis and a "conductive" position tilted and overlapping the end face of the metal honeycomb sandwich layer 10. When the heat-conducting baffle 27 is in the overlapping state, it forms a low thermal resistance path, which promotes the transfer of heat to the outer shell; when it is in the suspended state, it cuts off the direct heat conduction channel, forcing more heat to be released slowly through air gap radiation and natural convection.

[0027] like Figure 3 As shown, the outer heat dissipation shell 12 is fitted outside the metal honeycomb sandwich layer 10, and is made of stainless steel plate by stamping and welding, forming a double-layer hollow structure. The outer heat dissipation shell 12 includes an outer metal plate 13 and an inner support mesh plate 14, which are spaced 20 mm apart to form an annular cavity 15. The inner support mesh plate 14 is a perforated steel plate with an opening ratio of 40% and a hole diameter of 6 mm, used to reduce weight while ensuring structural rigidity. Multiple sets of heat-conducting fins 16 are arranged in the annular cavity 15. The heat-conducting fins 16 are made of copper alloy stamped into rectangular thin sheets, 80 mm long, 15 mm wide, and 1 mm thick, with a total of twenty-four fins evenly distributed circumferentially. One end of each heat-conducting fin 16 is spot-welded to the inner support mesh plate 14, and the other end extends freely to a distance of 5 mm from the inner surface of the outer metal plate 13 without contacting it to avoid forming a short-circuit thermal bridge.

[0028] The outer surface of the outer metal plate 13 is provided with an array of heat dissipation fins 17. The heat dissipation fins 17 extend axially, totaling thirty-six fins, and are evenly distributed circumferentially. Each heat dissipation fin 17 has a trapezoidal cross-section, with a base length of 25 mm, a top length of 10 mm, and a height that gradually decreases from 40 mm to 25 mm from bottom to top, conforming to the natural convection boundary layer thickening law, which is beneficial to improving heat exchange efficiency. The top of the outer heat dissipation shell 12 is equipped with a top cover 18, which is a flat-topped circular cover plate with a small vent hole 19 in the center. The vent hole has a diameter of 3 mm, allowing a small amount of air to enter and exit the annular cavity 15 due to thermal expansion and contraction, balancing the internal and external air pressure difference, while preventing a large amount of external dust from entering.

[0029] The bottom of the outer heat dissipation shell 12 is provided with an annular dust collection groove 30. The annular dust collection groove 30 has an upward opening and is located below the root of the heat dissipation fins 17. It is 30 mm wide and 15 mm deep and is used to capture dust particles that settle in the air. The bottom of the annular dust collection groove 30 has four small drainage holes 31, which are evenly distributed around the circumference. The holes have a diameter of 5 mm and are inclined downward to extend outside the shell, which facilitates regular flushing and cleaning of accumulated dust to prevent blockage and affect the heat dissipation effect.

[0030] The outer periphery of the metal honeycomb sandwich layer 10 is provided with a flow guide shroud 21. The flow guide shroud 21 is a thin-walled cylindrical structure, maintaining a uniform gap of 10 mm with the outer heat dissipation shell 12 to form an annular ventilation channel 24. The lower part of the flow guide shroud 21 has eight air inlet slits 22, evenly distributed circumferentially. Each air inlet slit 22 is 50 mm high and 30 mm wide, guiding external cold air into the annular ventilation channel 24 from the bottom. The upper part of the flow guide shroud 21 has an air outlet guide slope 23 with an inclination angle of 45 degrees, allowing the rising airflow to smoothly turn and exit, reducing flow resistance, enhancing the chimney effect, and improving natural convection heat transfer capacity.

[0031] In the actual installation process, the inner protective shell 1 is first fitted onto the outer wall of the heating equipment and connected and fixed to the support frame using the threaded holes 5 on the annular connecting flange 4. Then, the elastic buffer gasket 20, the nano-aerogel felt layer 7, and the vacuum microporous ceramic plate layer 8 are wrapped in sequence, and the metal honeycomb sandwich layer 10 is assembled into place. The heat pipe assembly 25 is pre-inserted into the corresponding layer, ensuring that the embedding depth at both ends is consistent. The outer heat dissipation shell 12 is hoisted and fitted as a whole, and after adjusting its position, the rotating shaft 28 is welded and fixed. The heat-conducting baffle 27 and the manual adjustment knob 29 are installed. Finally, the air guide shroud 21 is installed, and all components are checked to ensure they are securely assembled without any looseness or interference.

[0032] During operation, the heat generated by the heating equipment first acts on the inner protective shell 1. The corrugated uneven structure 2 extends the heat conduction path, and the anti-radiation coating 3 reflects most of the infrared radiation back to the equipment surface. Residual heat is transferred to the nano-aerogel felt layer 7 through the elastic buffer gasket 20. Due to its extremely low thermal conductivity, it significantly slows down the heat diffusion to the outside. When it further penetrates to the vacuum microporous ceramic plate layer 8, the negative pressure microporous structure blocks the gas convection heat transfer, and the metallized coating 9 reflects some of the heat radiation again. When it reaches the metal honeycomb sandwich layer 10, the phase change microcapsule particles 11 undergo repeated phase changes within the temperature fluctuation range, absorbing or releasing latent heat, thus playing a thermal buffering role. The locally accumulated heat is quickly dispersed laterally to the circumferential low-temperature area through the heat pipe assembly 25, avoiding the formation of hot spots. The outer heat dissipation shell 12 distributes the small amount of heat evenly through the heat-conducting fins 16, and achieves passive heat dissipation through the stepped heat dissipation fins 17 and the air convection in the annular ventilation channel 24. Operators can manually adjust the knob 29 to control the opening and closing of the heat-conducting baffle 27 according to the equipment's operating load. The baffle is closed under high load to reduce heat leakage, and opened during cooling to accelerate heat dissipation. Regular cleaning of the annular dust collection trough 30 maintains stable long-term heat dissipation performance.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multi-layer heat insulation and protection device for metal heat treatment, characterized in that, It includes an inner protective shell (1), a middle heat insulation layer group (6), an outer heat dissipation shell (12), and an interlayer thermal conductivity adjustment structure, wherein: The inner protective shell (1) is set close to the outer wall of the heating equipment and is made of high temperature resistant metal alloy. Its inner surface is provided with a corrugated concave-convex structure (2). The corrugated concave-convex structure (2) is spirally distributed along the circumference. The distance between adjacent peaks and valleys is 35 mm. The surface of the corrugated concave-convex structure (2) is provided with an anti-radiation coating (3). The anti-radiation coating (3) is formed by sintering a mixture of zirconium oxide and titanium dioxide in a mass ratio of 7:

3. The end of the inner protective shell (1) is provided with an annular connecting flange (4). Multiple sets of threaded holes (5) are evenly opened on the annular connecting flange (4). The intermediate heat insulation layer group (6) is composed of three layers of heat insulation materials stacked together, from the inside to the outside: nano aerogel felt layer (7), vacuum microporous ceramic plate layer (8), and metal honeycomb sandwich layer (10); the nano aerogel felt layer (7) is attached to the outer surface of the inner protective shell (1) and has a thickness of 20 mm; the vacuum microporous ceramic plate layer (8) is located outside the nano aerogel felt layer (7), and contains closed micron-sized pores inside and is under negative pressure. It has metallized coating (9) on both sides, and the metallized coating (9) is an aluminum-nickel alloy sputtering layer; the metal honeycomb sandwich layer (10) is located on the outermost side and is composed of a hexagonal cross-section metal tube array. The metal tube axis is perpendicular to the shell surface and the tube wall thickness is 0.3 mm. Its inner cavity is filled with phase change microcapsule particles (11), and the phase change temperature range of the phase change microcapsule particles (11) is 180 to 220 degrees Celsius; The outer heat dissipation shell (12) is fitted outside the metal honeycomb sandwich layer (10). The main body is a double-layer hollow structure, including an outer metal plate (13) and an inner support mesh plate (14), forming an annular cavity (15) between them. The annular cavity (15) is provided with heat-conducting fins (16). One end of the heat-conducting fins (16) is welded and fixed to the inner support mesh plate (14), and the other end extends to a position close to the outer metal plate (13) but does not contact it. The outer surface of the outer metal plate (13) is provided with axially extending heat dissipation fins (17). The heat dissipation fins (17) have a trapezoidal cross section, and the height gradually decreases from 40 mm to 25 mm from bottom to top. The top of the outer heat dissipation shell (12) is provided with a top cover (18). The top cover (18) has a small ventilation hole (19) with a diameter of 3 mm in the center. The interlayer thermal conductivity adjustment structure includes a heat pipe assembly (25) and a thermally conductive baffle (27). The heat pipe assembly (25) is evenly distributed circumferentially and has a U-shaped bending structure. Its two ends are respectively embedded in the vacuum microporous ceramic plate layer (8) and the metal honeycomb sandwich layer (10), and its middle part passes through the nano aerogel felt layer (7) and is attached to it. The heat pipe assembly (25) is evacuated and then filled with a working medium (26), which is R134a. The thermally conductive baffle (27) is installed in the gap between the metal honeycomb sandwich layer (10) and the outer heat dissipation shell (12) through a rotating shaft (28). One end of the rotating shaft (28) is connected to a manual adjustment knob (29). The thermally conductive baffle (27) is made of high thermal conductivity graphite material and can be rotated to selectively overlap or detach from the end of the metal honeycomb sandwich layer (10).

2. The multi-layer heat insulation and protection device for metal heat treatment according to claim 1, characterized in that: An elastic buffer gasket (20) is provided between the inner protective shell (1) and the intermediate heat insulation layer group (6). The elastic buffer gasket (20) is molded from high temperature silicone rubber and is continuously arranged in the circumferential direction. Its cross-section is trapezoidal and a positioning protrusion (33) is provided at the bottom. The positioning protrusion (33) is embedded in the connecting flange groove (32) on the outer surface of the inner protective shell (1).

3. The multi-layer heat insulation and protection device for metal heat treatment according to claim 1, characterized in that: The bottom of the outer heat dissipation shell (12) is provided with an annular dust collection groove (30). The annular dust collection groove (30) has an upward opening and is located in the root area of ​​the heat dissipation fins (17). A small drain hole (31) is provided at the bottom of the groove, and the drain hole (31) is inclined downward to the outside.

4. The multi-layer heat insulation and protection device for metal heat treatment according to claim 1, characterized in that: The outer periphery of the metal honeycomb sandwich layer (10) is provided with a flow guide shroud (21), and a uniform gap is maintained between the flow guide shroud (21) and the outer heat dissipation shell (12) to form an annular ventilation channel (24); the lower part of the flow guide shroud (21) is provided with an air inlet cutout (22), and the upper part is provided with an air outlet guide slope (23).

5. The multi-layer heat insulation protection device for metal heat treatment according to claim 1, characterized in that: The height difference between the crests and troughs of the corrugated structure (2) is 8 mm, the pitch is 35 mm, and the thickness of the anti-radiation coating (3) is 0.15 mm.

6. The multi-layer heat insulation protection device for metal heat treatment according to claim 1, characterized in that: The vacuum microporous ceramic plate layer (8) is 15 mm thick, with internal pore size of 1 to 10 micrometers and residual gas pressure of less than 1 kPa. The metallized coating layer (9) is 2 micrometers thick.

7. The multi-layer heat insulation protection device for metal heat treatment according to claim 1, characterized in that: The heat-conducting fins (16) are made of copper alloy by stamping, and a total of twenty-four fins are provided, which are evenly distributed along the circumference. Each fin is 80 mm long, 15 mm wide, and 1 mm thick.

8. The multi-layer heat insulation and protection device for metal heat treatment according to claim 1, characterized in that: The heat pipe assembly (25) is provided in eight groups, distributed at equal angles along the circumference, with an angle of 45 degrees between adjacent groups. Each heat pipe has an outer diameter of 8 mm, an inner diameter of 6 mm, and is filled with 15 grams of working fluid (26).

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