A bread oven wall heat dissipation waste heat recovery device

Abstract

This invention provides a waste heat recovery device for a bread oven wall, relating to the field of waste heat recovery technology. It includes an oven body, multiple heat collection boxes disposed on the outside of the oven body, an air outlet duct at the top of the recovery air duct, and an air inlet duct at the bottom of the recovery air duct. A thermal response throttling component includes a thermally conductive heat-response element connected to a heat-collecting baffle and a rotatably connected air valve plate. The thermal response throttling component adaptively adjusts the flow cross-section of the recovery air duct according to the temperature rise and fall of the heat-collecting baffle. A differential pressure bypass component is disposed on the main manifold, which opens when the thermal response throttling component reduces the flow cross-section, causing the negative pressure inside the main manifold to exceed a set value. The thermal response throttling component directly utilizes the temperature of the heat-collecting baffle to generate mechanical displacement, achieving adaptive airflow distribution to each zone without electrical control. This prioritizes recovery in high-temperature zones and actively limits flow in low-temperature zones. The structure is simple, the timeliness mode is intuitive, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a waste heat recovery device for bread oven wall heat dissipation. Background Technology

[0002] During operation, industrial bread ovens generate heat through combustion or electric heating, which is used for baking products but also dissipates into the environment through exhaust, doors, oven body connections, and oven walls. Existing energy-saving retrofits typically prioritize the recovery of sensible heat and latent heat of water vapor in the exhaust. However, exhaust recovery systems need to handle humid gases, oily volatiles, and potentially entrained fine dust. The equipment has high requirements for corrosion resistance, cleaning, and condensate emissions. For ovens that are already in operation and whose exhaust systems cannot be modified, directly installing exhaust heat exchangers may be limited by pipeline space, resistance, and combustion conditions.

[0003] Heat dissipation from the outer wall of the furnace is another type of persistent low-grade waste heat. If a wind jacket is simply installed on the outside of the furnace wall and a fan is used to make cold air flow directly along the surface of the furnace wall at high speed, although a high instantaneous heat exchange can be obtained, forced convection will significantly increase the heat transfer coefficient on the outside of the furnace wall, which will easily lead to additional heat extraction. This will cause the heating system inside the furnace to increase supplementary heating in order to maintain the set temperature. For areas where the furnace wall temperature is already low, it may also cause local temperature drop and heat redistribution.

[0004] Meanwhile, the temperature of the outer wall of a bread oven is usually not uniform along its length and height, and it continues to change during the heating, stable baking, standby, and shutdown stages. If a fixed air volume is used in each area, the heat extraction intensity of the high-temperature zone and the low-temperature zone cannot be matched, which can easily lead to the problem of insufficient heat utilization in the high-temperature zone and excessive cooling in the low-temperature zone. If multiple temperature sensors, frequency converter valve groups, and centralized controllers are used to adjust the temperature zone by zone, it will increase the cost of modification, wiring work, and maintenance burden on the food production site.

[0005] Therefore, there is a need for a device that is simple in structure, can be installed later, can recover heat from the furnace wall in sections without directly and forcibly flushing the furnace wall, and can automatically limit the heat extraction intensity according to the furnace wall temperature. Summary of the Invention

[0006] In view of this, the present invention provides a waste heat recovery device for oven wall heat dissipation in bread ovens, in order to solve the problems of increased heat loss of oven walls due to direct forced heat extraction in existing oven wall waste heat recovery, mismatch of fixed air volume when the temperature of each zone changes, complex control system, and difficulty in adapting the post-installed structure to the thermal expansion of the oven body.

[0007] The technical solution proposed in this invention is as follows: a waste heat recovery device for a bread oven wall, specifically including an oven body, multiple heat collection boxes disposed on the outside of the oven body, a main pipe connecting the air outlet slots of each heat collection box, a heat extraction unit and an exhaust fan unit connected to the air outlet end of the main pipe; a heat collection baffle is fixedly disposed inside the heat collection box, and a buffer heat collection cavity is formed between the heat collection baffle and the side wall of the oven body, and a recovery air duct is formed between the heat collection baffle and the sealing plate of the heat collection box; the buffer heat collection cavity maintains a non-forced flow state when the exhaust fan unit is working; the side of the heat collection baffle facing the oven body is a radiant heat absorption surface, and its On the other side, several heat dissipation fins are extended and inserted into the recovery air duct; the air outlet slot is located at the top of the recovery air duct, and the bottom of the recovery air duct is located at the air inlet slot. A thermal response throttling component is installed on the air inlet slot. The thermal response throttling component includes a thermally conductive thermally connected thermal response element and a rotatably connected air valve plate. The thermal response throttling component is used to adaptively increase or decrease the flow cross-section of the recovery air duct according to the temperature rise and fall of the thermally connected thermal isolation plate; a differential pressure bypass component is installed on the manifold. The differential pressure bypass component opens when the thermal response throttling component reduces the flow cross-section, causing the negative pressure inside the manifold to exceed a set value.

[0008] Furthermore, the radiative heat-absorbing surface is a temperature-resistant radiation-absorbing layer, and the hemispherical emissivity of the temperature-resistant radiation-absorbing layer is greater than or equal to 0.75.

[0009] Furthermore, several heat dissipation fins are arranged around the outer periphery of the heat dissipation fins and extend in a direction perpendicular to the airflow of the recovery air duct.

[0010] Furthermore, the thermal response element is one of a bimetallic strip, a bimetallic coil spring, or a wax-type thermal expansion actuator. One end of the thermal response element is fixed, and the other end is movable. The movable end of the thermal response element is fixedly connected to the valve plate shaft of the air valve plate. The thermal response component enables the damper plate to maintain a minimum opening of 5% to 20% of the maximum flow cross-section at low temperatures, and gradually increases the opening after the heat collector baffle reaches the preset opening temperature.

[0011] Furthermore, the preset opening temperature is 45-65℃, and the temperature of the heat collection baffle corresponding to the maximum opening of the air valve plate is 65-90℃.

[0012] Furthermore, the main manifold includes multiple air collection pipes and multiple horizontal air guide pipes and L-shaped air guide pipes. The air collection pipes are fixedly connected to the air outlet slots, the horizontal air guide pipes are fixedly connected between every two adjacent air collection pipes, and the L-shaped air guide pipes are fixedly connected to the top of the corresponding horizontal air guide pipes.

[0013] Furthermore, the differential pressure bypass assembly includes an air supply cylinder, a baffle plate rotatably disposed at the opening end of the air supply cylinder, and an elastic element or counterweight that applies a closing torque to the baffle plate. The air supply cylinder is fixedly connected to the L-shaped air guide pipe. The differential pressure bypass assembly starts to open when the negative pressure of the manifold relative to the environment reaches 80~250Pa. The elastic element is one of the following: torsion spring, coil spring, or tension spring.

[0014] Furthermore, the air intake slot is equipped with a removable filter screen, and the filter screen and the air valve plate are arranged on the upper and lower sides of the air intake slot respectively.

[0015] Furthermore, the exhaust unit is a temperature-resistant centrifugal fan, the heat extraction unit includes a heat extraction box and a heat exchanger that runs through the inside of the heat extraction box, the air outlet of the L-shaped air guide pipe is connected to the heat extraction box, and the exhaust unit is fixed to the top of the heat extraction box. The heat exchanger is a finned tube air-water heat exchanger.

[0016] The present invention has the following beneficial effects: 1. The buffer heat collection chamber can separate the furnace side wall from the airflow in the forced recovery airflow recovery duct, so that the forced recovery airflow will not directly sweep across the surface of the furnace side wall. The recovered heat is indirectly transferred to the heat collection baffle through the furnace wall. This can avoid the high-intensity heat extraction method of directly scouring the furnace side wall with cold air, and help reduce the disturbance to the original thermal balance of the oven.

[0017] Second, the thermal response throttling component directly utilizes the temperature of the heat collector baffle to generate mechanical displacement, realizing adaptive air volume distribution in each zone without electrical control. This allows for priority recovery in high-temperature zones and active flow restriction in low-temperature zones. The structure is simple, the time-efficiency mode is intuitive, and the cost is low. It does not require manual adjustment of the heat load in real time as needed.

[0018] Third, the differential pressure bypass component and the thermal response throttling component are used together to bypass and make up air when the forced recovery airflow inside the return main pipe and the recovery air duct decreases. This can maintain the stability of the induced draft unit and avoid forcibly increasing the suction intensity of each branch of the return main pipe in order to maintain the total air volume. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0020] In the attached diagram: Figure 1 This is a schematic diagram of the invention from one side view. Figure 2 This is a schematic diagram showing another side view of the entire invention; Figure 3 The diagram shows the connection path between the heat collection box and the heat extraction box in this invention; Figure 4 A schematic diagram of the internal structure of the heat collection box in this invention is shown in half section. Figure 5 A schematic diagram of the internal structure of the heat collection box in this invention is shown; Figure 6 A front view of the heat collection box in the cut-out state of the present invention is shown; Figure 7 A bottom-view schematic diagram of the heat collection box in this invention is shown; Figure 8 A schematic diagram of the structure of the air valve plate in this invention is shown; Figure 9 A diagram showing the assembly relationship between the bimetallic coil spring and the circular mounting cover in this invention is provided. Figure 10 A bottom-view schematic diagram of the air valve plate in this invention is shown; Figure 11 A schematic diagram of the bimetallic coil spring in this invention is shown; Figure 12 A schematic diagram showing the installation position of the heat exchanger in this invention is shown; Figure 13 A schematic diagram of the air supply cylinder in this invention is shown; Figure 14 A schematic diagram of the partial cross-section of the internal structure of the air supply cylinder in this invention is shown.

[0021] List of reference numerals in the attached diagram: 1. Furnace body; 2. Heat collection box; 201. Sealing plate; 202. Air collection pipe; 203. Horizontal air guide pipe; 204. Air valve plate; 2041. Valve plate pivot; 205. Heat collection partition plate; 2051. Heat dissipation fins; 206. Drawer sleeve; 207. Air outlet slot; 208. Air inlet slot; 209. Circular mounting cover; 2091. Rectangular air inlet; 3. L-shaped air guide tube; 301. Air supply cylinder; 3011. Limiting frame; 302. Baffle plate; 4. Heat extraction box; 5. Exhaust fan unit; 6. Heat exchanger; 7. Buffer heat collection chamber; 8. Recovery air duct; 9. Filter screen; 901. Positioning bolts; 10. Bimetallic coil spring; 1001. Hook and fastener; 11. Torsion spring. Detailed Implementation

[0022] A waste heat recovery device for bread oven walls includes the following embodiments: Example 1: Modular furnace wall waste heat recovery device (please refer to...) Figures 1 to 14 : This embodiment includes a furnace body 1 and a heat collection box 2. Two rows of heat collection boxes 2 are symmetrically fixed to the outer sides of the furnace body 1. A sealing plate 201 is fixed to the opening on the side of the heat collection box 2 away from the furnace body 1. A heat collection baffle 205 is fixed inside the heat collection box 2. A buffer heat collection cavity 7 is formed between the heat collection baffle 205 and the side wall of the furnace body 1. A recovery air duct 8 is formed between the heat collection baffle 205 and the sealing plate 201. An air outlet slot 207 and an air inlet slot 208 are respectively opened at the top and bottom of the recovery air duct 8. The buffer heat collection cavity 7 and the recovery air duct 8 are separated by the heat collection baffle 205. The forced recovery airflow generated by the induced draft unit 5 only moves in the recovery air duct 8. The direction of movement of the forced recovery airflow in the recovery air duct 8 is from bottom to top. The heat collection baffle 205 faces the furnace body 1. A heat-resistant radiation absorption layer is provided on one side of the sidewall of the furnace body 1. The heat-resistant radiation absorption layer is made of heat-resistant black inorganic coating or a dark surface formed by oxidation treatment and is sprayed on one side of the heat collection baffle 205. Preferably, the emissivity of the heat-resistant radiation absorption layer is not less than 0.75. The high emissivity of the heat-resistant radiation absorption layer can improve the absorption of radiant heat from the furnace body 1 by the heat collection baffle 205. The periphery of the buffer heat collection cavity 7 is restricted by heat-resistant sealing strips or folded edge windproof structures to limit air exchange, but airtightness is not required. The thickness of the buffer heat collection cavity 7 is 12~35mm, preferably 20mm. The heat collection baffle 205 is a metal plate with a thickness of 0.6~2.0mm, preferably 1.0mm. The thickness of the recovery air duct 8 is 20~30mm, preferably 25mm.

[0023] Unlike structures that directly draw cold air at high speed against the furnace wall, this device has a forced recovery airflow recovery duct 8 on the back of the heat collection baffle 205. Even if the induced draft changes, the side wall of the furnace body 1 is still mainly facing the buffer heat collection cavity 7. Therefore, the change in the forced convection heat transfer coefficient will not directly affect the surface of the side wall of the furnace body 1.

[0024] Several heat dissipation ribs 2051 are evenly distributed on the side of the heat collection baffle 205 facing the sealing plate 201. The heat dissipation ribs 2051 extend into the recovery air duct 8 and are perpendicular to the airflow direction inside the recovery air duct 8. Several heat dissipation fins are arranged on the outer periphery of the heat dissipation ribs 2051 to help the heat collection baffle 205 dissipate heat fully and quickly into the recovery air duct 8. The height of the heat dissipation ribs 2051 is 5~18mm and the adjacent spacing is 15~40mm.

[0025] The heat emitted from the side wall of the furnace body 1 is first transferred to the heat collection baffle 205 through radiation and weak natural convection in the buffer heat collection cavity 7, and then dissipated into the recovery air duct 8 through several heat dissipation fins 2051, and carried away by the forced recovery airflow inside the recovery air duct 8.

[0026] A drawer sleeve 206 is welded to the lower side of the air intake slot 208. The drawer sleeve 206 has an open end and a closed end. A rectangular air inlet 2091 is opened through the bottom wall of the drawer sleeve 206. A filter screen 9 is slidably inserted inside the drawer sleeve 206. The filter screen 9 covers the lower side of the air intake slot 208. A positioning bolt 901 is threaded through one end of the filter screen 9. The positioning bolt 901 is inserted into the bottom wall of the heat collection box 2 to fix the filter screen 9. The diameter of the filter screen hole 9 is 0.5~1.5mm, which is used to intercept larger flour lumps and debris.

[0027] Multiple air valve plates 204 are rotatably mounted on the upper side of the air intake slot 208. A valve plate shaft 2041 is fixedly connected to the constrained end of each air valve plate 204. Both ends of the valve plate shaft 2041 are respectively rotatably engaged with the bottom sides of the heat collection baffle 205 and the sealing plate 201. Multiple circular mounting covers 209 are fixedly arranged on the side of the heat collection baffle 205 facing the sealing plate 201. A bimetallic coil spring 10 is embedded within each circular mounting cover 209. A hook-and-fixed component 1001 is integrally formed at the fixed end of the bimetallic coil spring 10. 01 penetrates the peripheral wall of the circular mounting cover 209 and is fixed to the peripheral wall. The movable end of the bimetallic coil spring 10 is fixedly connected to the valve plate rotating shaft 2041. One end of the valve plate rotating shaft 2041 facing the heat collection baffle 205 is engaged with the side wall at the center of the circular mounting cover 209. The side of the bimetallic coil spring 10 away from the air valve plate 204 is in close contact with the heat collection baffle 205 for heat conduction. The bimetallic coil spring 10 is composed of a metal active layer with a large coefficient of thermal expansion and a metal passive layer with a small coefficient of thermal expansion, which are firmly rolled together. The active layer wants to extend more, while the passive layer extends less, and they are mutually constrained, forcing the whole to bend towards the side with less expansion. By making the active and passive layers into bimetallic coil springs 10, the two layers will control the tightening or loosening of the bimetallic coil springs 10 through the thermal expansion or contraction effect generated by their different sensitivities to temperature. This, in turn, controls the up-and-down swinging movement of the damper plate 204 according to the temperature rise and fall, so as to adaptively adjust the opening of its body and the flow cross-section of the recovery air duct 8. This allows the heat load of the device to automatically adjust with the rise and fall of the heat dissipation level of the furnace body 1. By increasing or decreasing the volume, the hotter oven wall sections on the same oven can automatically receive a larger volume of recovered air, while the colder sections can automatically limit the flow, eliminating the need to configure temperature sensors and electric regulating valves for each module. When the heat collector baffle 205 is at a low temperature, it transfers less heat to the bimetallic coil spring 10, and the bimetallic coil spring 10 does not undergo thermal expansion and remains in its initial state, keeping the air valve plate 204 at a minimum opening of 10%. When the temperature of the heat collector baffle 205 rises to about 55°C, the air valve plate 204 begins to open significantly, reaching its maximum opening at 75°C.

[0028] A gas collecting pipe 202 is welded to the top of the air outlet slot 207, and a horizontal gas guide pipe 203 is welded between every two gas collecting pipes 202. A heat exchange box 4 is fixedly installed above the furnace body 1. Two L-shaped gas guide pipes 3 are symmetrically fixed to both sides of the heat exchange box 4. The end of the L-shaped gas guide pipe 3 away from the heat exchange box 4 is fixedly connected to the corresponding horizontal gas guide pipe 203. A gas supply cylinder 301 is welded to the vertical part of the L-shaped gas guide pipe 3. A limit frame 301 is integrally formed at the open end of the gas supply cylinder 301. A baffle plate 302 is rotatably installed in the opening of the gas supply cylinder 301. The two ends of the rotating shaft of the baffle plate 302 are rotatably engaged with the top end of the side wall of the gas supply cylinder 301. A torsion spring 11 is fitted on one end of the rotating shaft of the baffle plate 302 that protrudes from the gas supply cylinder 301. One end of the torsion spring 11 is fixedly connected to the side wall of the gas supply cylinder 301, and the other end is fixedly connected to the side wall of the gas supply cylinder 301. The end is fixedly connected to the rotating shaft of the baffle plate 302 to provide the baffle plate 302 with a torsional closing torque. The baffle plate 302 abuts against the limiting frame 3011 to close the opening of the air supply cylinder 301. The air collection pipe 202, the horizontal air guide pipe 203 and the L-shaped air guide pipe 3 are connected together to form the manifold. When the opening of the damper plate 204 decreases, the flow section of the recovery air duct 8 decreases, and the inside of the manifold is in a negative pressure state relative to the outside. When the negative pressure of the manifold relative to the environment reaches about 140Pa, the baffle plate 302 begins to swing upward and open under the push of the external pressure to supply external air into the manifold to balance the pressure difference between the inside and outside of the manifold. After the baffle plate 302 opens to supply air, the negative pressure inside the manifold decreases, and the bypass valve plate 23 rotates and closes under the automatic rebound action of the torsion spring 11.

[0029] The heat exchanger 6 is installed inside the heat exchange box 4. The heat exchanger 6 is a finned tube air-water heat exchanger, which is used to preheat the cleaning water or other non-drinking process water with the recovered hot air. It can also send the recovered hot air to the combustion air preheating section through an independent air duct. In addition, if it is used for preheating the make-up air in the fermentation chamber or workshop, it is preferred to use a partition air-to-air heat exchanger for secondary heat exchange to avoid the air near the outer surface of the oven from directly entering the space with high cleanliness requirements.

[0030] A draft unit 5 is fixedly installed at the top of the heat collection box 4. The draft unit 5 can be a high-temperature resistant centrifugal fan with a total designed air volume of 350-700 m³ / h and a static pressure of 150-350 Pa. The high-temperature resistant centrifugal fan can be fixed at a fixed speed or low gear through one-time debugging, so there is no need to configure an independent fan for each module. Under the suction of the draft unit 5, the heat collected in the heat collection box 2 is introduced into the heat collection box 4 by the forced recovery airflow in the recovery air duct 8 and the manifold for heat exchange in the heat exchanger 6. The draft unit 5 can keep the recovery air duct 8 and the manifold as a whole under a slight negative pressure to ensure that even if there is a small leak at the joint of the heat collection box 2, the main infiltration is ambient air, reducing the escape of hot air from the production area.

[0031] Example 2: Thermal balance design example: To illustrate the feasibility of this device, a set of engineering design calculation examples are provided. These examples are thermal estimates and do not represent completed field test data. The heat collection module consists of a heat collection box 2, a heat collection baffle 205, a buffer heat collection cavity 7, and a recovery air duct 8. Assuming the total effective heat collection area of ​​the heat collection module is 12m², the average temperature of the outer surface of the furnace wall during stable baking is approximately 105℃, the ambient temperature is approximately 25℃, the average temperature of the heat collection baffle 205 is approximately 65℃, the thickness of the buffer heat collection cavity 7 is 20mm, the combined effective radiation coefficient between the furnace wall and the heat collection baffle 205 is approximately 0.75, and the natural convection heat transfer coefficient of the buffer cavity is approximately 3W / (m²·K). Then, the radiative heat transfer is approximately 3.8kW, the natural convection heat transfer is approximately 1.4kW, and the total heat transferred to the heat collection baffle 205 is approximately 5.2kW.

[0032] When the induced draft is estimated at approximately 500 m³ / h, the average density of the recovered air is 1.15 kg / m³, and the specific heat capacity at constant pressure is estimated at 1.0 kJ / (kg·K), the air mass flow rate is approximately 0.16 kg / s. If the temperature rise of the hot air before the heat utilization end is approximately 30 K, then the heat carried by the air is approximately 4.8 kW, which is on the same order of magnitude as the heat that can be provided by the heat collector side. This indicates that matching this size and air volume is feasible in engineering. In actual design, the number of modules and the total air volume should be adjusted according to the specific furnace wall temperature, the area that can be arranged, and the requirements of the heat utilization end.

[0033] Working principle: In the initial stage of heating of furnace body 1, the temperature of heat collection baffle 205 is low, and each air valve plate 204 keeps a small opening. The main air volume of the induced draft unit 5 is supplemented by the differential pressure bypass component. At this time, only a small amount of air flows through each heat collection module, and the heat dissipation of furnace body 1 will not be forcibly increased in the low temperature stage. As the temperature of furnace body 1 rises, the heat is transferred to heat collection baffle 205 through buffer heat collection cavity 7. The bimetallic coil spring 10 gradually drives the air valve plate 204 to increase the opening, and the forced recovery airflow of the heat collection module corresponding to the side wall of furnace body 1 increases accordingly.

[0034] During the stable baking stage, the temperature difference between different sidewall zones of the furnace body 1 will be directly reflected in the opening difference of each air valve plate 204. The higher temperature zone undertakes a larger amount of waste heat recovery. If the production cycle is reduced or a certain furnace zone is cooled down, the corresponding air valve plate 204 will automatically shrink. When multiple branches of the manifold simultaneously shrink the forced recovery flow, the differential pressure bypass component will open to maintain the working point of the manifold and the induced draft unit 5. After the furnace is shut down, the induced draft unit 5 can be closed, and the heat collection module will return to the outer cover structure with a buffer air layer, i.e., the buffer heat collection cavity 7, and will not require continuous active cooling.

[0035] This invention is not limited to the specific dimensions and materials described above. The buffer heat collection chamber 7 and the recovery air duct 8 can be formed by an integrally bent heat collection baffle 205 or by a detachable plate. The thermal response component can be a bimetallic element or other thermally actuated element that does not require power and can generate mechanical displacement with temperature. The differential pressure bypass component can be a spring valve plate, a counterweight flap, or a diaphragm valve structure. As long as the synergistic relationship between non-forced buffer heat collection on the furnace wall side, heat transfer through the baffle, forced recovery on the back of the baffle, zoned thermal response flow restriction, and differential pressure bypass of the main pipe is maintained, all are equivalent implementations of the technical concept of this invention.

[0036] This invention can be manufactured and installed using conventional metal plate processing, mechanical connection, fans and partition heat exchange equipment. It is suitable for energy-saving retrofitting of existing industrial bread ovens and has clear industrial application conditions and repeatability.

Claims

1. A waste heat recovery device for oven wall heat dissipation of bread oven, comprising oven body (1), multiple heat collection boxes (2) disposed on the outside of oven body (1), a main pipe connecting the air outlet slots (207) of each heat collection box (2), a heat collection unit and an exhaust unit (5) connected to the air outlet end of the main pipe. Its features are, The heat collection box (2) is fixedly equipped with a heat collection baffle (205). A buffer heat collection cavity (7) is formed between the heat collection baffle (205) and the side wall of the furnace body (1). A recovery air duct (8) is formed between the heat collection baffle (205) and the sealing plate (201) of the heat collection box (2). The buffer heat collection cavity (7) maintains a non-forced flow state when the induced draft unit (5) is working. The side of the heat collection baffle (205) facing the furnace body (1) is a radiant heat absorption surface, and the other side is provided with several heat dissipation ribs (2051) that extend and are inserted into the recovery air duct (8). The air outlet slot (207) is provided with An air inlet groove (208) is provided at the top of the recovery air duct (8) and at the bottom of the recovery air duct (8). A thermal response throttling component is provided on the air inlet groove (208). The thermal response throttling component includes a thermal response element that is thermally connected to the heat collection baffle (205) and a wind valve plate (204) that is rotatably connected to the thermal response element. The thermal response throttling component is used to adaptively increase or decrease the flow cross section of the recovery air duct (8) according to the temperature rise and fall of the heat collection baffle (205). A differential pressure bypass component is provided on the manifold. The differential pressure bypass component opens when the thermal response throttling component reduces the flow cross section and causes the negative pressure inside the manifold to exceed a set value.

2. The waste heat recovery device for bread oven wall heat dissipation according to claim 1, characterized in that, The radiative heat-absorbing surface is a temperature-resistant radiation-absorbing layer, and the hemispherical emissivity of the temperature-resistant radiation-absorbing layer is greater than or equal to 0.

75.

3. The waste heat recovery device for bread oven wall heat dissipation according to claim 1, characterized in that, The heat dissipation fins (2051) are arranged with several heat dissipation fins on their outer periphery and extend in a direction perpendicular to the airflow of the recovery air duct (8).

4. The waste heat recovery device for bread oven wall heat dissipation according to claim 1, characterized in that, The thermal response component is one of a bimetallic strip, a bimetallic coil spring (10), or a wax-type thermal expansion actuator. One end of the thermal response component is fixed and the other end is movable. The movable end of the thermal response component is fixedly connected to the valve plate shaft (2041) of the air valve plate (204). The thermal response component enables the damper plate (204) to maintain a minimum opening of 5% to 20% of the maximum flow cross-section at low temperatures, and gradually increases the opening after the temperature of the heat collector baffle (205) reaches the preset opening temperature.

5. A waste heat recovery device for bread oven walls according to claim 4, characterized in that, The preset opening temperature is 45-65℃, and the temperature of the heat collection baffle (205) when the air valve plate (204) reaches its maximum opening is 65-90℃.

6. The waste heat recovery device for bread oven wall heat dissipation according to claim 1, characterized in that, The main duct includes multiple air collecting pipes (202) and multiple horizontal air guiding pipes (203) and L-shaped air guiding pipes (3). The air collecting pipes (202) are fixedly connected to the air outlet slots (207). The horizontal air guiding pipes (203) are fixedly connected between every two adjacent air collecting pipes (202). The L-shaped air guiding pipes (3) are fixedly connected to the top of the corresponding horizontal air guiding pipes (203).

7. A waste heat recovery device for bread oven walls according to claim 6, characterized in that, The differential pressure bypass assembly includes an air supply cylinder (301), a baffle plate (302) rotatably disposed at the opening end of the air supply cylinder (301), and an elastic element or counterweight that applies a closing torque to the baffle plate (302). The air supply cylinder (301) is fixedly connected to the L-shaped air guide pipe (3). The differential pressure bypass assembly starts to open when the negative pressure of the manifold relative to the environment reaches 80~250Pa. The elastic element is one of torsion spring (11), coil spring, or tension spring.

8. The waste heat recovery device for bread oven wall heat dissipation according to claim 1, characterized in that, The air inlet slot (208) is provided with a removable filter screen (9), and the filter screen (9) and the air valve plate (204) are arranged on the upper and lower sides of the air inlet slot (208).

9. A waste heat recovery device for bread oven walls according to claim 1, characterized in that, The exhaust unit (5) is a temperature-resistant centrifugal fan. The heat extraction unit includes a heat extraction box (4) and a heat exchanger (6) that runs through the inside of the heat extraction box (4). The air outlet of the L-shaped air guide pipe (3) is connected to the heat extraction box (4). The exhaust unit (5) is fixed to the top of the heat extraction box (4). The heat exchanger (6) is a finned tube air-water heat exchanger.

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