A heating device

Abstract

The application relates to the field of electric heating, and discloses a heating device which comprises an outer cover, a heat-conducting inner ring assembly located in the outer cover, a heat-insulating shield assembly and a heat-driven deformation part, the shield assembly is wrapped outside the heat-conducting inner ring assembly and is spaced apart from the heat-conducting inner ring assembly to form a heat-insulating cavity, the outer cover is suitable for wrapping heat-insulating cotton, the heat-insulating cotton is in a loose state and is suitable for providing space for the expansion of the shield assembly; the heat-driven deformation part is located in the heat-insulating cavity, two ends of the heat-driven deformation part are connected with the heat-conducting inner ring assembly and the shield assembly respectively, the heat-driven deformation part is suitable for deforming to drive the shield assembly to move along the radial direction and change the thickness of the heat-insulating cavity when the temperature changes. The thickness of the heat-insulating cavity can be automatically adjusted along with the temperature, the heating efficiency is ensured, the heat-insulating effect under high temperature is improved, heat energy loss is reduced, and energy consumption is lowered.

Description

Technical Field

[0001] This invention relates to the field of electric heating technology, and more specifically, to a heating device. Background Technology

[0002] The heating coil of an injection molding machine is a heating device installed on the outside of the screw extrusion barrel. It mainly heats and melts the plastic raw material inside the barrel through infrared heating components. Most existing heating coils are fixed double-layer structures with an insulating cavity between the outer and inner layers. If the insulating cavity is large, the heating time varies, and the heating efficiency decreases. Therefore, to improve heating efficiency, the gap in the insulating cavity is made smaller. However, as the temperature rises and approaches a holding state, the insulation capacity of the small-gap insulating cavity begins to decrease, and heat is easily lost. Increasing the thickness of the insulating cavity, but keeping it below a critical value (beyond the critical value, the gas inside the cavity undergoes natural convection due to temperature difference, forming a "thermal cycle," which weakens the insulation effect), will improve the insulation effect and reduce heat loss. However, the existing insulating thickness is fixed and cannot automatically adjust the insulation performance according to actual temperature changes; that is, it is impossible to achieve the effect of stronger insulation performance at higher temperatures. Summary of the Invention

[0003] To address at least one of the aforementioned problems, the present invention provides a heating device comprising an outer casing, a heat-conducting inner ring assembly located within the outer casing, a heat-insulating shield assembly, and a heat-driven deformable component. The heat-conducting inner ring assembly is adapted to wrap around the outside of the screw extrusion barrel of an injection molding machine for heating. The shield assembly covers the outside of the heat-conducting inner ring assembly and is spaced apart from the heat-conducting inner ring assembly by a heat-insulating cavity. The shield assembly is adapted to expand or contract, and the outside of the shield assembly is wrapped with heat-insulating cotton. The outer casing is adapted to wrap the heat-insulating cotton, which is loosely arranged to provide clearance when the shield assembly expands. The heat-driven deformable component is located within the heat-insulating cavity, and its two ends are respectively connected to the heat-conducting inner ring assembly and the heat-insulating shield assembly. The heat-driven deformable component is adapted to deform when the temperature changes, thereby driving the shield assembly to move radially and changing the thickness of the heat-insulating cavity.

[0004] Optionally, the heat-conducting inner ring assembly includes an outer ring, multiple first metal parts, multiple second metal parts, and multiple quartz tubes. The multiple first metal parts and multiple second metal parts are staggered and rotatably connected. Adjacent first metal parts and multiple second metal parts can rotate relative to each other. The multiple first metal parts and multiple second metal parts are spliced ​​together to wrap around the outside of the injection molding machine screw extrusion barrel. Each first metal part and multiple second metal part is inserted with a quartz tube. An electric heating wire passes through the multiple quartz tubes in series. The multiple first metal parts and multiple second metal parts are all inserted into the outer ring.

[0005] Optionally, the heat insulation shield assembly includes multiple arc-shaped shields and multiple flexible corrugated segments. The multiple arc-shaped shields and multiple flexible corrugated segments are arranged circumferentially in an alternating pattern and are fixedly connected in sequence. The thermally driven deformation member is connected to the arc-shaped shield. When the arc-shaped shield moves under the drive of the thermally driven deformation member, the flexible corrugated segments deform.

[0006] Optionally, the heat insulation shield assembly includes a grid frame, a reflective layer, a heat insulation layer, and a protective cover arranged from the inside out. The reflective layer is polished aluminum foil, the heat insulation layer is aerogel felt, the grid frame and the protective cover are both made of stainless steel, and the grid frame is welded to the protective cover.

[0007] Optionally, the aerogel felt has a thickness of 10-20 mm, the protective cover has a thickness of 1-1.5 mm, and the aerogel felt and the protective cover are fixedly connected by rivets.

[0008] Optionally, the protective cover is formed by bending a plate, and both ends of the protective cover in the plate state are fixedly provided with buckles, and the two buckles are fixedly connected by bolts.

[0009] Optionally, the thermally driven deformable component includes an active layer and a passive layer, which are manufactured by a rolling composite metallurgical process. The active layer is a nickel-chromium alloy, and the passive layer is an iron-nickel alloy. The thermally driven deformable component has a Z-shaped cross-section and includes an upper horizontal section, a middle inclined section, and a lower horizontal section. The lower horizontal section is fixedly connected to the heat-conducting inner ring assembly, and the upper horizontal section is hingedly connected to the heat insulation shield assembly.

[0010] Optionally, the thickness ratio of the active layer to the passive layer is 1:1; the active layer is adapted to be close to the side of the heat-conducting inner ring assembly, and the passive layer is disposed on the side away from the heat-conducting inner ring assembly; the coefficient of thermal expansion of the active layer is greater than the coefficient of thermal expansion of the passive layer; when heated, the elongation of the active layer is greater than the elongation of the passive layer, so that the heat-driven deformable member bends towards the passive layer and drives the middle inclined section to arch outward, thereby driving the upper horizontal section and the heat insulation shield assembly to move radially outward.

[0011] Optionally, when the temperature range of the thermally driven deformable component is 20-40°C, the intermediate inclined section remains unchanged, and the thickness of the heat insulation cavity is 2-3 mm; when the temperature rises to the temperature range of 180-220°C, the intermediate inclined section bends, driving the upper horizontal section to move radially outward by 3-4 mm, and the thickness of the heat insulation cavity increases to 5-7 mm; when the temperature decreases, the thermally driven deformable component returns to its original shape and drives the heat insulation shield assembly to reset.

[0012] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0013] 1. The thickness of the insulation cavity can be automatically adjusted with temperature. When heating begins, the insulation cavity is thin, allowing for rapid temperature rise and high heating efficiency. At high temperatures, the insulation cavity thickens under the action of the heat-driven deformation component, improving the insulation effect, reducing heat loss and energy consumption. When the temperature drops, the insulation cavity automatically recovers. The entire process requires no electrical control or manual intervention, and can adaptively adjust based solely on temperature changes.

[0014] 2. The first and second metal parts are made of metal materials with good thermal conductivity. After the electric heating component heats the first and second metal parts, they can form a heating rod. The first and second metal parts are in contact with the heated body, which reduces the conduction links and can transfer heat to the heated body in a timely manner, reduce heat loss, improve heating response speed, and reduce cost.

[0015] 3. The flexible corrugated section is more likely to deform under stress. When the arc-shaped cover moves under the drive of the thermally driven deformable parts, the flexible corrugated section adapts to make up the margin through expansion and contraction, ensuring the integrity of the heat insulation cavity. Moreover, the resistance of the flexible corrugated section to deformation is small during the movement of the arc-shaped cover, ensuring the smoothness of the whole movement.

[0016] 4. Polished aluminum foil, as a reflective layer, is low in cost and can effectively prevent heat loss. The reflective layer, together with the heat insulation layer, forms a composite heat insulation layer, which further improves the heat insulation effect, reduces heat loss, and lowers energy consumption. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the heating device in an embodiment of the present invention;

[0018] Figure 2 This is a cross-sectional view of the heating device in an embodiment of the present invention;

[0019] Figure 3 This is a structural diagram of the heat-conducting inner ring assembly in an embodiment of the present invention;

[0020] Figure 4 for Figure 3 Enlarged view of section A in the middle;

[0021] Figure 5 This is a structural diagram of the heat insulation shield assembly in an embodiment of the present invention;

[0022] Figure 6 This is a cross-sectional view of the heat-conducting inner ring assembly, the heat insulation shield assembly, and the thermally driven deformable component in an embodiment of the present invention.

[0023] Figure 7 for Figure 6 Enlarged view of section B;

[0024] Figure 8 for Figure 6 Enlarged view of section C.

[0025] Explanation of reference numerals in the attached drawings: 1. Outer cover; 11. Insulation cotton; 2. Thermally conductive inner ring assembly; 21. Outer ring; 22. First metal part; 23. Second metal part; 24. Connecting protrusion; 25. Connecting groove; 3. Thermal insulation shield assembly; 31. Protective cover; 32. Arc-shaped cover; 33. Flexible corrugated section; 4. Thermally driven deformable part; 5. Thermal insulation cavity. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figure 1-8 This application will be described in further detail.

[0027] This invention provides a heating device, referring to... Figure 1 and Figure 2The heating device includes an outer cover 1, a heat-conducting inner ring assembly 2 located inside the outer cover 1, a heat-insulating protective cover assembly 3, and a heat-driven deformable component 4. The heat-conducting inner ring assembly 2 is adapted to wrap around the outside of the injection molding machine screw extrusion barrel for heating. The protective cover assembly covers the outside of the heat-conducting inner ring assembly 2 and is spaced apart from the heat-conducting inner ring assembly 2 by a heat-insulating cavity 5. The protective cover assembly is adapted to expand or contract. The protective cover assembly is wrapped with heat-insulating cotton 11, and the outer cover 1 is adapted to wrap the heat-insulating cotton 11. The heat-insulating cotton 11 is in a loose state to provide room for the protective cover assembly to expand. The heat-driven deformable component 4 is located inside the heat-insulating cavity 5. Both ends of the heat-driven deformable component 4 are connected to the heat-conducting inner ring assembly 2 and the heat-insulating shield assembly 3, respectively. The heat-driven deformable component 4 is adapted to deform when the temperature changes, so as to drive the shield assembly to move radially, change the thickness of the heat-insulating cavity 5, improve the heat insulation effect, reduce heat loss and reduce energy consumption. After the temperature drops, the heat-insulating cavity 5 will automatically recover. The whole process does not require electrical control or manual intervention, and can be adaptively adjusted by relying solely on temperature changes.

[0028] Since the screw extrusion barrel of the injection molding machine is circular, the assembled shape of the outer cover 1, the heat-conducting inner ring assembly 2, and the heat insulation shield assembly 3 is also circular.

[0029] Reference Figure 3 The heat-conducting inner ring assembly 2 includes an outer ring 21, multiple first metal parts 22, multiple second metal parts 23, and multiple quartz tubes. The multiple first metal parts 22 and multiple second metal parts 23 are staggered and rotatably connected; the assembled multiple first metal parts 22 and multiple second metal parts 23 are suitable for wrapping the outside of the injection molding machine screw extrusion barrel. Each first metal part 22 and multiple second metal parts 23 contains a quartz tube, and multiple quartz tubes have heating wires connected in series inside, reducing the number of connection points for the heating wires and lowering energy loss. The inner walls of the multiple quartz tubes are in contact with the heating wires. The heating wires are connected to a power source to convert electrical energy into heat energy, thereby heating the quartz tubes. The quartz tubes themselves have high thermal conductivity, enabling rapid and uniform heat transfer; they also effectively isolate current, avoiding the risk of leakage; and the quartz tubes can withstand temperatures above 1000 degrees Celsius. Multiple first metal parts 22 and multiple second metal parts 23 are inserted into the outer ring 21. The outer ring 21 wraps around the multiple first metal parts 22 and multiple second metal parts 23 to form a whole, preventing them from becoming scattered.

[0030] Reference Figure 3 and Figure 4The first metal part 22 has integrally formed connecting protrusions 24 on its opposite outer walls, and the second metal part 23 has integrally formed connecting grooves 25 on its opposite outer walls. The connecting protrusions 24 are adapted to slide and insert into the connecting grooves 25, and the connecting protrusions 24 and the connecting grooves 25 are adapted to rotate, so that adjacent first metal parts 22 and second metal parts 23 can rotate relative to each other to fit a circular, elliptical, or polygonal heated body. The outer ring 21 is formed by bending a rectangular stainless steel plate, with one end of the bent rectangular stainless steel plate overlapping the other end, and then multiple spot welds are made at intervals to fix it into a circular outer ring 21. Through spot welding technology, on the one hand, the outer ring 21 is ensured to maintain a stable annular state; on the other hand, compared with a whole weld, spot welding only requires prying open the weld points, which improves the convenience of disassembly and maintenance. The heat insulation cavity 5 is located between the outer ring 21 and the heat insulation shield assembly 3.

[0031] Reference Figure 5 and Figure 6 The heat insulation shield assembly 3 includes a grid frame, a reflective layer, a heat insulation layer, and a protective cover 31 arranged from the inside out. Both the grid frame and the protective cover 31 are made of stainless steel and are welded together. The grid frame is 0.3mm thick, and a space is formed between the grid frame and the protective cover 31 for the installation of the reflective layer and the heat insulation layer, thus ensuring that the reflective layer and the heat insulation layer can expand or contract together with the protective cover 31. The reflective layer is made of polished aluminum foil, which is low in cost and effectively prevents heat loss. The heat insulation layer is made of aerogel felt with a thickness of 10-20mm, and the protective cover 31 has a thickness of 1-1.5mm. The aerogel felt and the protective cover 31 are fixedly connected by rivets. In this embodiment, the protective cover 31 is preferably 1mm thick; the aerogel felt has a thickness of 10mm, a thermal conductivity of 0.021W / (m·K), and a density of 210kg / m³. Additionally, the reflective layer can also be bonded to the inside of the heat insulation layer with a high-temperature resistant adhesive.

[0032] Both the grid frame and the protective cover 31 are formed by bending a single rectangular plate. The protective cover 31 has latches welded to both ends in its plate state. The two latches are fixed together by bolts, allowing for easy disassembly of the heat insulation cover assembly 3 by simply loosening the bolts securing the latches. During installation, the bolts are tightened for fixation, ensuring ease of assembly and disassembly.

[0033] Reference Figures 5 to 7The protective cover 31 comprises multiple arc-shaped covers 32 and multiple flexible corrugated sections 33. The arc-shaped covers 32 and flexible corrugated sections 33 are arranged alternately and fixedly connected sequentially, i.e., one arc-shaped cover 32, one flexible corrugated section 33, another arc-shaped cover 32, and another flexible corrugated section 33 are arranged in this manner. The arc-shaped covers 32 are made of stainless steel, and the flexible corrugated sections 33 are made of polyimide, thus giving the flexible corrugated sections 33 flexible deformation capabilities and allowing them to remain relatively stable at 300℃ for extended periods, without breaking after 200,000 bends. The flexible corrugated sections 33 conform to the outer wall of the arc-shaped ends of the arc-shaped covers 32 and are fixed together at intervals by multiple rivets and washers. A polytetrafluoroethylene (PTFE) sealing gasket is sandwiched between the flexible corrugated sections 33 and the arc-shaped covers 32 to prevent heat loss, and the PTFE sealing gasket can be used continuously in an environment with a temperature of 260℃. The maximum temperature of the heating device is 220℃. One end of the thermally driven deformable component 4 is connected to the arc-shaped cover 32. When the arc-shaped cover 32 moves under the drive of the thermally driven deformable component 4, it causes the flexible corrugated section 33 to deform. The flexible corrugated section 33 adapts to make up the margin by stretching and contracting, ensuring the integrity of the heat insulation cavity 5. Moreover, the resistance of the flexible corrugated section 33 in deformation is small during the movement of the arc-shaped cover 32, ensuring the smoothness of the whole action.

[0034] It is worth noting that both ends of the outer ring 21 are bent outward with outer heat insulation baffles; both ends of the reflective layer, heat insulation layer and protective cover 31 are bent inward with inner heat insulation baffles. The inner heat insulation baffles are located inside the outer heat insulation baffles and fit tightly against each other, thus making the heat insulation cavity 5 a relatively sealed space. In addition, during the expansion or contraction of the heat insulation cover assembly 3, gaps are less likely to appear at the axial end under the action of the inner heat insulation baffles and the outer heat insulation baffles, so that heat can be dissipated quickly.

[0035] Reference Figure 6 and Figure 8 The thermally driven deformable component 4 comprises an active layer and a passive layer, which are manufactured using a combined rolling metallurgical process. The active layer is a nickel-chromium alloy, and the passive layer is an iron-nickel alloy. The coefficient of thermal expansion of the nickel-chromium alloy is (18±1)×10⁻⁶. -6 / ℃; the coefficient of thermal expansion of the iron-nickel alloy is (1.2±0.2)×10 -6 / ℃. The cross-section of the heat-driven deformable component 4 is Z-shaped, and it includes an upper horizontal section, a middle inclined section, and a lower horizontal section. The lower horizontal section is fixedly connected to the outer ring 21 by rivets, and the upper horizontal section is hingedly connected to the heat insulation cover assembly 3. Each arc-shaped cover 32 is provided with multiple heat-driven deformable components 4 at intervals along its circumference. The heat-driven deformable component 4 is elongated, and its length direction is consistent with the axial direction of the arc-shaped cover 32, thus providing sufficient power to drive the arc-shaped cover 32 to move. Each arc-shaped cover 32 has hinged lugs welded and fixed at both ends along its axial direction, with the same number of hinged lugs corresponding to the heat-driven deformable components 4. The length ends of each heat-driven deformable component 4 are welded and fixed with hinged shafts, which are rotatably inserted into the corresponding hinged lugs to achieve hinged connection.

[0036] The thickness ratio of the active layer to the passive layer is 1:1; the active layer is positioned closer to the heat-conducting inner ring assembly 2, while the passive layer is positioned further away from the heat-conducting inner ring assembly 2. Since the coefficient of thermal expansion of the active layer is greater than that of the passive layer, when heated, the active layer elongates more than the passive layer, causing the heat-driven deformable member 4 to bend towards the passive layer and drive the middle inclined section to arch outwards, thus moving the upper horizontal section and the heat insulation shield assembly 3 radially outwards, thereby increasing the size of the heat insulation cavity 5.

[0037] The outer cover 1 is an open annular shape, with locking buckles welded to both sides of the outer wall at the opening. These two buckles are connected by bolts to ensure the outer cover 1 tightly encloses the internal components. The insulation cotton 11 is loosely arranged between the outer cover 1 and the heat insulation shield assembly 3. Both ends of the outer cover 1 have inwardly bent retaining rings, which prevent axial movement of the insulation cotton, heat insulation shield assembly 3, and heat-conducting inner ring assembly 2. Furthermore, insulation cotton is also filled between the retaining rings and the outer insulation retaining ring, providing insulation protection at the ends as well.

[0038] The implementation principle of the heating device in this embodiment is as follows: at a room temperature of 20-40℃, the middle inclined section of the heat-driven deformable member 4 remains unchanged, forming an angle of 45 degrees with the horizontal plane. The thickness of the heat-insulating cavity 5 is 2-3mm, and in this embodiment, the thickness of the heat-insulating cavity 5 is preferably 2.5mm. After the conductive inner ring assembly is energized, heat is conducted to the cylinder through the conductive inner ring assembly, and part of the heat is transferred to the arc-shaped cover 32 through the heat-insulating cavity 5.

[0039] When the temperature of the conductive inner ring assembly rises to 180℃, the thermally driven deformable component 4 is heated. Because the elongation of the active layer (inner side, high expansion) is greater than that of the passive layer (outer side, low expansion), the thermally driven deformable component 4 bends towards the passive layer (i.e., outwards). The middle inclined section changes from a sloping line to an outward-arching arc, with the chord length shortening by 4-6 mm. Since the initial inclination of the middle inclined section is 45 degrees, the displacement due to the shortened chord length is decomposed into a radial outward component and a vertical upward component, while the lower horizontal section remains fixed. Geometric calculations show that the upper horizontal section pushes the arc-shaped cover 32 outwards by 3-4 mm through the hinge point. The thickness of the heat-insulating cavity 5 increases to 5-7 mm, significantly increasing the thermal resistance of the air layer, causing the external temperature of the arc-shaped cover 32 to decrease. When the temperature rises to the maximum of 220℃, the thermally driven deformable component 4 remains in its directional change state.

[0040] When the temperature of the conductive inner ring component drops below 120°C, the thermally driven deformable part 4 cools and shrinks, the middle inclined section returns to its inclined straight shape, which in turn drives the arc-shaped cover 32 to reset, the thickness of the heat insulation cavity 5 returns to 2.5mm, and the device returns to the heat preservation mode.

[0041] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this disclosure, unless otherwise explicitly specified and limited, "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] The above embodiments are merely illustrative of several implementation methods of this disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this disclosure, and these modifications and improvements all fall within the protection scope of this disclosure.

Claims

1. A heating device, characterized in that: The device includes an outer cover (1), a heat-conducting inner ring assembly (2) located inside the outer cover (1), a heat-insulating shield assembly (3), and a heat-driven deformable component (4). The heat-conducting inner ring assembly (2) is adapted to wrap around the outside of the injection molding machine screw extrusion barrel for heating. The shield assembly covers the outside of the heat-conducting inner ring assembly (2) and is spaced apart from the heat-conducting inner ring assembly (2) by a heat-insulating cavity (5). The shield assembly is adapted to expand or contract. The shield assembly is wrapped with heat-insulating cotton (11). The outer cover (1) The heat-insulating cotton (11) is loosely wrapped to allow room for the expansion of the protective cover assembly. The heat-driven deformable part (4) is located inside the heat-insulating cavity (5). The two ends of the heat-driven deformable part (4) are connected to the heat-conducting inner ring assembly (2) and the heat-insulating protective cover assembly (3) respectively. The heat-driven deformable part (4) is adapted to deform when the temperature changes to drive the protective cover assembly to move radially and change the thickness of the heat-insulating cavity (5).

2. The heating device according to claim 1, characterized in that: The heat-conducting inner ring assembly (2) includes an outer ring (21), multiple first metal parts (22), multiple second metal parts (23), and multiple quartz tubes. The multiple first metal parts (22) and multiple second metal parts (23) are arranged in an alternating manner and rotatably connected. Adjacent first metal parts (22) and second metal parts (23) can rotate relative to each other. After being spliced ​​together, the multiple first metal parts (22) and multiple second metal parts (23) are suitable for wrapping the outside of the injection molding machine screw extrusion barrel. Each first metal part (22) and each second metal part (23) is inserted with a quartz tube. Electric heating wires are connected in series through the multiple quartz tubes. The multiple first metal parts (22) and the multiple second metal parts (23) are all inserted into the outer ring (21).

3. The heating device according to claim 1, characterized in that: The heat insulation shield assembly (3) includes multiple arc-shaped shields (32) and multiple flexible corrugated sections (33). The multiple arc-shaped shields (32) and multiple flexible corrugated sections (33) are arranged circumferentially and fixedly connected in sequence. The thermally driven deformation member (4) is connected to the arc-shaped shields (32). When the arc-shaped shields (32) move under the drive of the thermally driven deformation member (4), the flexible corrugated sections (33) deform.

4. The heating device according to claim 1, characterized in that: The heat insulation shield assembly (3) includes a grid frame, a reflective layer, a heat insulation layer and a protective cover (31) arranged from the inside out. The reflective layer is a polished aluminum foil, the heat insulation layer is an aerogel felt, the grid frame and the protective cover (31) are both made of stainless steel, and the grid frame is welded to the protective cover (31).

5. The heating device according to claim 4, characterized in that: The aerogel felt has a thickness of 10-20 mm, the protective cover (31) has a thickness of 1-1.5 mm, and the aerogel felt and the protective cover (31) are fixedly connected by rivets.

6. The heating device according to claim 4, characterized in that: The protective cover (31) is formed by bending a plate. Both ends of the protective cover (31) in the plate state are fixed with buckles, and the two buckles are fixedly connected by bolts.

7. The heating device according to any one of claims 1-6, characterized in that: The thermally driven deformable part (4) includes an active layer and a passive layer. The active layer and the passive layer are made by a rolling composite metallurgical process. The active layer is a nickel-chromium alloy and the passive layer is an iron-nickel alloy. The cross-section of the thermally driven deformable part (4) is Z-shaped. The thermally driven deformable part (4) includes an upper horizontal section, a middle inclined section and a lower horizontal section. The lower horizontal section is fixedly connected to the heat-conducting inner ring assembly (2), and the upper horizontal section is hinged to the heat insulation shield assembly (3).

8. The heating device according to claim 7, characterized in that: The thickness ratio of the active layer to the passive layer is 1:1; the active layer is adapted to be close to the side of the heat-conducting inner ring assembly (2), and the passive layer is located away from the side of the heat-conducting inner ring assembly (2). The thermal expansion coefficient of the active layer is greater than that of the passive layer. When heated, the elongation of the active layer is greater than that of the passive layer, so that the heat-driven deformable member (4) bends toward the passive layer and drives the middle inclined section to arch outward, thereby driving the upper horizontal section and the heat insulation shield assembly (3) to move radially outward.

9. The heating device according to claim 7, characterized in that: When the thermally driven deformable part (4) is in the temperature range of 20-40℃, the middle inclined section remains unchanged, and the thickness of the heat insulation cavity (5) is 2-3mm; when the temperature rises to the temperature range of 180-220℃, the middle inclined section bends, causing the upper horizontal section to move radially outward by 3-4mm, and the thickness of the heat insulation cavity (5) increases to 5-7mm; when the temperature drops, the thermally driven deformable part (4) returns to its original state and drives the heat insulation shield assembly (3) to reset.

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