Oxygen content circulating gas purification heat treatment furnace

Abstract

The invention relates to the technical field of heat treatment furnaces, in particular to an oxygen content circulating gas purification heat treatment furnace which comprises a purification mechanism, and the purification mechanism comprises a replacement frame, a handle, a fixing hole, a first filter screen, an activated carbon layer, a barrier net, an oxygen removal layer, a drying layer and a protruding block. After the gas enters the purification frame, the gas firstly penetrates through a first filter screen to intercept large-particle impurities in the gas, then organic matters and peculiar smell in the gas are adsorbed through an activated carbon layer, and then small particles in the gas are blocked by a blocking net before the gas enters an oxygen removal layer; and then through a multi-stage purification structure, the oxygen content in the gas is conveniently reduced, the situation that materials are oxidized in the heat treatment furnace is prevented, meanwhile, large particles and small particles are filtered in advance, loads of core consumables such as activated carbon and palladium catalysts are reduced, the replacement period is prolonged, and the maintenance frequency and the consumable consumption cost are reduced.

Description

Technical Field

[0001] This application relates to the field of heat treatment furnace technology, and in particular to a heat treatment furnace for purifying oxygen-content circulating gas. Background Technology

[0002] Heat treatment is a crucial step in metal processing. By controlling the heating, holding, and cooling processes, the mechanical properties and microstructure of materials can be improved. During heat treatment, the control of the furnace atmosphere, especially the oxygen content, is paramount, directly affecting the surface quality and performance of the material. Currently, industrially used heat treatment furnaces often employ inert gas (such as nitrogen or argon) protection or vacuum heat treatment technology to reduce material oxidation. However, these methods suffer from high costs, complex equipment, and high energy consumption. In recent years, with increasing environmental protection requirements and the need for resource conservation, gas recycling technology has gradually gained attention.

[0003] Traditional gas purification methods mostly employ inert gas protection, vacuum heat treatment, and gas recycling. Inert gas protection is costly and results in significant gas waste; vacuum heat treatment involves expensive equipment and has limited applicability; and existing filtration systems in gas recycling cannot efficiently remove oxygen, leading to persistent material oxidation problems. Furthermore, the high-temperature gas after heat treatment is often not recycled, resulting in energy waste. Therefore, an oxygen-content circulating gas purification heat treatment furnace is proposed. Summary of the Invention

[0004] The purpose of this application is to provide an oxygen-content circulating gas purification heat treatment furnace, including a main structure, and further comprising: A purification mechanism, located outside the main body; The purification mechanism includes a replacement rack, a handle, fixing holes, a first filter, an activated carbon layer, a barrier mesh, an oxygen removal layer, a drying layer, and protrusions. The replacement rack is fixedly connected to a handle, and fixing holes are provided on both sides of the replacement rack for fixing the replacement rack. The replacement rack has a first filter for pre-filtration inside, an activated carbon layer and a barrier mesh for further filtration inside, an oxygen removal layer for reducing the oxygen content in the gas inside, and a drying layer for absorbing water molecules in the gas inside. Two protrusions are fixedly connected to the side of the replacement rack away from the handle.

[0005] Preferably, the activated carbon layer is located between the first filter screen and the barrier screen, the deoxygenation layer is located on the side of the barrier screen away from the activated carbon layer, and the deoxygenation layer is located on the side of the drying layer away from the barrier screen.

[0006] Preferably, the main body includes a heat treatment furnace shell, the inner wall of the heat treatment furnace shell is provided with an exhaust hole, the interior of the heat treatment furnace shell is provided with a gas guide pipe, and the inner wall of the heat treatment furnace shell is uniformly provided with a plurality of gas outlet holes.

[0007] Preferably, all of the several air outlets are connected to the air guide pipe, the exhaust port is located above the air outlet, the exhaust port penetrates the outer shell of the heat treatment furnace, and the replacement rack is located on the side of the outer shell of the heat treatment furnace away from the opening.

[0008] Preferably, a circulation mechanism is provided on the side of the main body, and the circulation mechanism is located between the purification mechanism and the circulation mechanism. The circulation mechanism includes a fan, a cooling pipe, fins and a heating pipe.

[0009] Preferably, a heating tube is provided inside the fin, with both ends of the heating tube extending through the inner wall of the fin to the bottom of the fin, and the fin is located on the side of the cooling tube.

[0010] Preferably, the fan is located inside the exhaust port, one end of the cooling pipe is fixedly connected to the side of the heat treatment furnace shell away from the opening, the interior of the cooling pipe is connected to the exhaust port, one end of the heating pipe is fixedly connected to the side of the heat treatment furnace shell away from the opening, and the interior of the heating pipe is connected to the interior of the gas guide pipe.

[0011] Preferably, the circulation mechanism has a fixing mechanism inside, the fixing mechanism includes a purification frame, the purification frame has two cavities inside, a handle is slidably connected inside the cavity, an elastic element is provided inside the cavity, a locking block is fixedly connected to one end of the handle, two grooves are provided on the side of the purification frame, an expansion airbag is provided inside the groove, a supporting airbag is provided on the inner wall of the purification frame, a slider is slidably connected inside the purification frame, and a ventilation groove is provided inside the purification frame.

[0012] Preferably, the ends of the two handles away from the locking block extend through the inner walls of the two cavities to both sides of the purification rack. The locking block is located inside the purification rack. The handles are elastically connected to the inner walls of the cavities through elastic elements. The interior of the supporting airbag is connected to the interior of the two expanding airbags through a ventilation groove. The side of the supporting airbag away from the ventilation groove is fixedly connected to the side of the slider near the ventilation groove. The side of the locking block away from the slider is provided with an inclined surface.

[0013] Preferably, the two sides of the purification rack are fixedly connected to the ends of the cooling pipe and heating pipe away from the outer shell of the heat treatment furnace, respectively. The interior of the purification rack is connected to the interior of the cooling pipe and heating pipe. The size of the protrusion is adapted to the size of the groove. The replacement rack is slidably connected to the inner wall of the outer shell of the heat treatment furnace. The first filter screen is located inside the purification rack on the side near the cooling pipe.

[0014] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention facilitates the purification of gases in a heat treatment furnace by combining a first filter and a deoxygenation layer. After entering the purification rack, the gas first passes through the first filter, which intercepts large particulate impurities. Then, it passes through an activated carbon layer to adsorb organic matter and odors. Before entering the deoxygenation layer, small particles are blocked by a barrier mesh. When the gas enters the deoxygenation layer, the palladium catalyst or chemical absorbent deoxygenates the gas. Finally, the gas passes through a drying layer to absorb moisture. This multi-stage purification structure facilitates the reduction of oxygen content in the gas, preventing the materials from being oxidized in the heat treatment furnace. At the same time, the pre-filtration of large and small particles reduces the load on core consumables such as activated carbon and palladium catalyst, extends the replacement cycle, and reduces maintenance frequency and consumable costs. 2. This invention facilitates gas circulation by combining cooling pipes and heating pipes. When the fan is activated, gas from the heat treatment furnace shell enters the cooling pipes through the exhaust vents and then flows into the purification rack. During this process, the heat of the gas is absorbed by the fins on the side of the cooling pipes. After purification by the purification mechanism, the gas is discharged into the heating pipes and reheated along the pipes into the fins. It then enters the gas guide pipes and re-enters the heat treatment furnace shell through several exhaust vents. As the gas flows through the cooling pipes, the fins absorb heat and dissipate it to the outside, lowering the gas temperature and preventing high-temperature damage to subsequent purification components. The purified gas then enters the fins through the heating pipes, utilizing the heat stored in the cooling stage for reheating. The heat recovery rate is ≥70%, reducing heating energy consumption. Simultaneously, the gas is recycled through the exhaust vents, cooling, purification, heating, and return process, reducing the emission of protective gases such as nitrogen and argon, lowering rare gas consumption costs, and avoiding heat waste caused by open emissions. 3. This invention, through the combination of a locking block and an inflatable airbag, facilitates the assembly and disassembly of the purification structure. The first filter, activated carbon layer, barrier mesh, deoxygenation layer, and drying layer are sequentially installed inside the replacement rack. Then, the protrusion on the replacement rack is aligned with the groove on the purification rack, and the replacement rack is moved closer to the interior of the purification rack. This causes the side of the replacement rack to press against the inclined surface of the locking block, moving it out of the purification rack and pressing against the elastic element. When the protrusion engages with the groove, the locking block aligns with the fixing hole. At this point, the locking block will engage with the fixing hole under the action of the handle's elasticity. Additional tools are required to install and remove the replacement rack, greatly improving maintenance efficiency. It also facilitates the replacement and cleaning of its internal purification structure. During this process, the first filter, activated carbon layer, barrier mesh, deoxygenation layer, and drying layer inside the replacement rack will squeeze the slider, causing the slider to move towards the support airbag inside the purification rack and compress the support airbag. This allows the gas inside the support airbag to enter the expansion airbag through the ventilation groove, causing the expansion airbag to expand and fill the gap between the groove and the protrusion, improving the sealing of the device and eliminating the risk of gas leakage caused by tiny gaps.

[0015] Attached image caption Figure 1 This is a schematic diagram of the internal structure of the applicant's organization; Figure 2 These are schematic diagrams of the overall structure of Embodiment 1 and Embodiment 2 of this application; Figure 3 This is a schematic cross-sectional view of the circulation mechanism of this application; Figure 4 This is a cross-sectional structural diagram of the fixing mechanism of this application; Figure 5 This is a cross-sectional structural diagram of the purification mechanism in this application; Figure 6 This application Figure 5 Enlarged structural diagram at point A in the middle; Figure 7 This is a schematic diagram showing the structural relationship and fit between the fins and the heating tube in this application; Explanation of reference numerals in the attached drawings: 1. Purification mechanism; 101. Replacement rack; 102. Handle; 103. Fixing hole; 104. First filter screen; 105. Activated carbon layer; 106. Barrier mesh; 107. Deoxygenation layer; 108. Drying layer; 109. Protrusion; 2. Main body mechanism; 201. Heat treatment furnace shell; 202. Exhaust port; 203. Air guide pipe; 204. Air outlet; 3. Circulation mechanism; 301. Fan; 302. Cooling pipe; 303. Fin; 304. Heating pipe; 4. Fixing mechanism; 401. Purification rack; 402. Cavity; 403. Handle; 404. Elastic element; 405. Locking block; 406. Groove; 407. Support airbag; 408. Slider; 409. Ventilation groove; 410. Inflatable airbag. Detailed Implementation

[0016] The following is in conjunction with the appendix Figure 1 To be continued Figure 7 This application will be described in further detail below.

[0017] Example 1: An oxygen-content circulating gas purification heat treatment furnace, referring to... Figures 1 to 7 Including main body 2, it also includes: Purification mechanism 1 is located outside the main body 2; The purification mechanism 1 includes a replacement frame 101, a handle 102, a fixing hole 103, a first filter screen 104, an activated carbon layer 105, a barrier screen 106, an oxygen removal layer 107, a drying layer 108, and protrusions 109. The handle 102 is fixedly connected to the replacement frame 101. Fixing holes 103 are provided on both sides of the replacement frame 101 for fixing the replacement frame 101. The first filter screen 104 for pre-filtration is provided inside the replacement frame 101. The activated carbon layer 105 and the barrier screen 106 for further filtration are provided inside the replacement frame 101. The oxygen removal layer 107 for reducing the oxygen content in the gas is provided inside the replacement frame 101. The drying layer 108 for absorbing water molecules in the gas is provided inside the replacement frame 101. Two protrusions 109 are fixedly connected to the side of the replacement frame 101 away from the handle 102.

[0018] The activated carbon layer 105 is located between the first filter screen 104 and the barrier screen 106. The deoxygenation layer 107 is located on the side of the barrier screen 106 away from the activated carbon layer 105. The deoxygenation layer 107 is located on the side of the drying layer 108 away from the barrier screen 106.

[0019] The main body 2 includes a heat treatment furnace shell 201. The inner wall of the heat treatment furnace shell 201 is provided with an exhaust hole 202. The interior of the heat treatment furnace shell 201 is provided with a gas guide pipe 203. The inner wall of the heat treatment furnace shell 201 is evenly provided with a plurality of air outlet holes 204. The plurality of air outlet holes 204 are all connected to the gas guide pipe 203. The exhaust hole 202 is located above the air outlet hole 204 and penetrates the heat treatment furnace shell 201. The replacement rack 101 is located on the side of the heat treatment furnace shell 201 away from the opening.

[0020] A circulation mechanism 3 is provided on the side of the main body 2. The circulation mechanism 3 is located between the purification mechanism 1 and the circulation mechanism 3. The circulation mechanism 3 includes a fan 301, a cooling pipe 302, a fin 303 and a heating pipe 304. The heating pipe 304 is provided inside the fin 303. Both ends of the heating pipe 304 extend through the inner wall of the fin 303 to the bottom of the fin 303. The fin 303 is located on the side of the cooling pipe 302.

[0021] The blower 301 is located inside the exhaust port 202. One end of the cooling pipe 302 is fixedly connected to the side of the heat treatment furnace shell 201 away from the opening. The interior of the cooling pipe 302 is connected to the exhaust port 202. One end of the heating pipe 304 is fixedly connected to the side of the heat treatment furnace shell 201 away from the opening. The interior of the heating pipe 304 is connected to the interior of the air guide pipe 203.

[0022] The implementation principle of this application embodiment is as follows: by setting up a first filter screen 104 and a deoxygenation layer 107, etc., the gas in the heat treatment furnace is purified. After the gas enters the purification rack 401, it first passes through the first filter screen 104, which intercepts large particulate impurities in the gas. Then, it passes through the activated carbon layer 105 to adsorb organic matter and odors in the gas. Before entering the deoxygenation layer 107, the small particles are blocked by the barrier screen 106. When the gas enters the deoxygenation layer 107, the palladium catalyst or chemical absorbent in it will deoxygenate the gas. Finally, the moisture in the gas is absorbed by the drying layer 108. The multi-stage purification structure facilitates the reduction of oxygen content in the gas, preventing the material from being oxidized in the heat treatment furnace. At the same time, the pre-filtration of large and small particles reduces the load on core consumables such as activated carbon and palladium catalyst, extends the replacement cycle, and reduces the maintenance frequency and consumable consumption costs. By configuring cooling pipes 302 and heating pipes 304, gas circulation is facilitated. When the fan 301 is activated, gas inside the heat treatment furnace shell 201 enters the cooling pipes 302 through the exhaust port 202, and then flows along the cooling pipes 302 into the purification rack 401. During this process, the heat of the gas is absorbed by the fins 303 on the side of the cooling pipes 302. After purification by the purification mechanism 1, the gas is discharged into the heating pipes 304, and then flows along the pipes of the heating pipes 304 into the fins 303 for reheating. Afterward, it enters the gas guide pipe 203 and exits from several outlets... The gas re-enters the interior of the heat treatment furnace shell 201 through the vent 204. When the gas flows through the cooling pipe 302, the fins 303 absorb heat and dissipate it to the outside, reducing the gas temperature and preventing high temperature damage to subsequent purification components. The purified gas enters the fins 303 through the heating pipe 304 and is reheated using the heat stored in the cooling stage. The heat recovery rate is ≥70%, reducing heating energy consumption. At the same time, the gas is recycled through the exhaust vent, cooling, purification, heating and return process, reducing the emission of protective gases such as nitrogen and argon, reducing the cost of rare gas consumption, and avoiding heat waste caused by open exhaust.

[0023] Example 2: An oxygen-content circulating gas purification heat treatment furnace, referring to... Figures 3 to 6The circulation mechanism 3 has a fixing mechanism 4 inside, which includes a purification rack 401. The purification rack 401 has two cavities 402 inside, and a handle 403 is slidably connected inside the cavity 402. An elastic element 404 is installed inside the cavity 402. A locking block 405 is fixedly connected to one end of the handle 403. The side of the purification rack 401 has two grooves 406. An expansion airbag 410 is installed inside the groove 406. A support airbag 407 is installed on the inner wall of the purification rack 401. A slider 408 is slidably connected inside the purification rack 401. A ventilation groove 409 is opened inside the purification rack 401.

[0024] The ends of the two handles 403 away from the locking block 405 extend through the inner walls of the two cavities 402 to both sides of the purification rack 401. The locking block 405 is located inside the purification rack 401. The handles 403 are elastically connected to the inner walls of the cavities 402 through the elastic element 404. The interior of the support airbag 407 is connected to the interior of the two expansion airbags 410 through the ventilation groove 409. The side of the support airbag 407 away from the ventilation groove 409 is fixedly connected to the side of the slider 408 near the ventilation groove 409. The side of the locking block 405 away from the slider 408 is provided with a slope.

[0025] The two sides of the purification rack 401 are fixedly connected to the ends of the cooling pipe 302 and the heating pipe 304 away from the heat treatment furnace shell 201, respectively. The interior of the purification rack 401 is connected to the interior of the cooling pipe 302 and the heating pipe 304. The size of the protrusion 109 is adapted to the size of the groove 406. The replacement rack 101 is slidably connected to the inner wall of the heat treatment furnace shell 201. The first filter screen 104 is located inside the purification rack 401 on the side close to the cooling pipe 302.

[0026] The implementation principle of this application embodiment is as follows: By setting up a structure such as a locking block 405 and an expansion airbag 410, the installation and removal of the purification structure is facilitated. The first filter screen 104, activated carbon layer 105, barrier screen 106, deoxygenation layer 107, and drying layer 108 are sequentially installed inside the replacement frame 101. Then, the protrusion 109 on the replacement frame 101 is aligned with the groove 406 on the purification frame 401, and the replacement frame 101 is moved closer to the interior of the purification frame 401. The side of the replacement frame 101 presses against the inclined surface of the locking block 405, causing it to move out of the interior of the purification frame 401 and press against the elastic member 404. When the protrusion 109 engages with the groove 406, the locking block 405 is aligned with the fixing hole 103. At this time, the locking block 405 will be elastically engaged by the handle 403. Under the action of the fixing hole 103, the replacement rack 101 can be installed and removed without additional tools, which greatly improves maintenance efficiency and facilitates the replacement and cleaning of its internal purification structure. During this process, the first filter 104, activated carbon layer 105, barrier mesh 106, deoxygenation layer 107 and drying layer 108 inside the replacement rack 101 will squeeze the slider 408, causing the slider 408 to move towards the support airbag 407 inside the purification rack 401 and compress the support airbag 407. This allows the gas in the support airbag 407 to enter the expansion airbag 410 through the ventilation groove 409, causing the expansion airbag 410 to expand and fill the gap between the groove 406 and the protrusion 109, improving the sealing of the device and eliminating the risk of gas leakage caused by small gaps.

[0027] The working principle and usage process of this invention are as follows: First, the first filter 104, activated carbon layer 105, barrier mesh 106, deoxygenation layer 107, and drying layer 108 are sequentially installed inside the replacement frame 101. Then, the protrusion 109 on the replacement frame 101 is aligned with the groove 406 on the purification frame 401, and the replacement frame 101 is moved closer to the interior of the purification frame 401. This causes the side of the replacement frame 101 to press against the inclined surface of the locking block 405, causing it to move out of the interior of the purification frame 401 and press against the elastic member 404. When the protrusion 109 engages with the groove 406, the locking block 405 engages with the fixing hole 10. 3. Alignment: At this time, the locking block 405 will engage with the fixing hole 103 under the action of the handle 403's elasticity. During this process, the first filter 104, activated carbon layer 105, barrier mesh 106, deoxygenation layer 107, and drying layer 108 inside the replacement rack 101 will squeeze the slider 408, causing the slider 408 to move towards the support airbag 407 inside the purification rack 401, compressing the support airbag 407. This allows the gas inside the support airbag 407 to enter the expansion airbag 410 through the ventilation groove 409, causing the expansion airbag 410 to expand and fill the gap between the groove 406 and the protrusion 109. Then, when the device is working, the heat treatment furnace is started, and the temperature and atmosphere parameters are set. Simultaneously, the fan 301 is started, causing the gas inside the furnace shell 201 to enter the cooling pipe 302 through the exhaust port 202, and then flow along the cooling pipe 302 into the purification rack 401. During this process, the heat of the gas is absorbed by the fins 303 on the side of the cooling pipe 302. After entering the purification rack 401, the gas first passes through the first filter 104, which intercepts large particulate impurities in the gas. Subsequently, it passes through the activated carbon layer 105, which adsorbs organic matter and other pollutants in the gas. Odors are eliminated, and before entering the deoxygenation layer 107, the tiny particles are blocked by the barrier net 106. When the gas enters the deoxygenation layer 107, the palladium catalyst or chemical absorbent in it will remove oxygen. Finally, after the moisture in the gas is absorbed by the drying layer 108, it is discharged into the heating tube 304 and enters the fin 303 along the pipe of the heating tube 304 to be reheated. Finally, after entering the gas guide pipe 203, it will re-enter the interior of the heat treatment furnace shell 201 through several gas outlets 204, realizing gas circulation and purification.

[0028] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. An oxygen-content circulating gas purification heat treatment furnace, comprising a main body (2), characterized in that: Also includes: Purification mechanism (1), which is located outside the main body mechanism (2); The purification mechanism (1) includes a replacement rack (101), a handle (102), a fixing hole (103), a first filter screen (104), an activated carbon layer (105), a barrier screen (106), an oxygen removal layer (107), a drying layer (108), and a protrusion (109). The handle (102) is fixedly connected to the replacement rack (101). Fixing holes (103) for fixing the replacement rack (101) are provided on both sides of the replacement rack (101). The replacement rack (101) is provided with a first filter screen (104) for pre-filtration, an activated carbon layer (105) and a barrier screen (106) for further filtration, an oxygen removal layer (107) for reducing the oxygen content in the gas, a drying layer (108) for absorbing water molecules in the gas, and two protrusions (109) are fixedly connected to the side of the replacement rack (101) away from the handle (102).

2. The oxygen content circulating gas purification heat treatment furnace according to claim 1, characterized in that, The activated carbon layer (105) is located between the first filter screen (104) and the barrier screen (106), the deoxygenation layer (107) is located on the side of the barrier screen (106) away from the activated carbon layer (105), and the deoxygenation layer (107) is located on the side of the drying layer (108) away from the barrier screen (106).

3. The oxygen content circulating gas purification heat treatment furnace according to claim 1, characterized in that, The main body (2) includes a heat treatment furnace shell (201), an exhaust hole (202) is provided on the inner wall of the heat treatment furnace shell (201), a gas guide pipe (203) is provided inside the heat treatment furnace shell (201), and a plurality of gas outlet holes (204) are uniformly provided on the inner wall of the heat treatment furnace shell (201).

4. The oxygen content circulating gas purification heat treatment furnace according to claim 3, characterized in that, Several of the air outlets (204) are connected to the air guide pipe (203), the exhaust port (202) is located above the air outlet (204), the exhaust port (202) penetrates the heat treatment furnace shell (201), and the replacement rack (101) is located on the side of the heat treatment furnace shell (201) away from the opening.

5. The oxygen content circulating gas purification heat treatment furnace according to claim 3, characterized in that, The main body (2) is provided with a circulation mechanism (3) on its side. The circulation mechanism (3) is located between the purification mechanism (1) and the circulation mechanism (3). The circulation mechanism (3) includes a fan (301), a cooling pipe (302), fins (303) and a heating pipe (304).

6. The oxygen content circulating gas purification heat treatment furnace according to claim 5, characterized in that, A heating tube (304) is provided inside the fin (303). Both ends of the heating tube (304) extend through the inner wall of the fin (303) to the bottom of the fin (303). The fin (303) is located on the side of the cooling tube (302).

7. The oxygen content circulating gas purification heat treatment furnace according to claim 5, characterized in that, The fan (301) is located inside the exhaust port (202). One end of the cooling pipe (302) is fixedly connected to the side of the heat treatment furnace shell (201) away from the opening. The interior of the cooling pipe (302) is connected to the exhaust port (202). One end of the heating pipe (304) is fixedly connected to the side of the heat treatment furnace shell (201) away from the opening. The interior of the heating pipe (304) is connected to the interior of the air guide pipe (203).

8. The oxygen content circulating gas purification heat treatment furnace according to claim 5, characterized in that, The circulation mechanism (3) is provided with a fixing mechanism (4) inside. The fixing mechanism (4) includes a purification rack (401). The purification rack (401) has two cavities (402) inside. A handle (403) is slidably connected inside the cavity (402). An elastic element (404) is provided inside the cavity (402). A locking block (405) is fixedly connected to one end of the handle (403). Two grooves (406) are provided on the side of the purification rack (401). An expansion airbag (410) is provided inside the groove (406). A supporting airbag (407) is provided on the inner wall of the purification rack (401). A slider (408) is slidably connected inside the purification rack (401). A ventilation groove (409) is provided inside the purification rack (401).

9. The oxygen content circulating gas purification heat treatment furnace according to claim 8, characterized in that, The two handles (403) extend through the inner walls of the two cavities (402) to both sides of the purification rack (401) at the ends away from the locking block (405). The locking block (405) is located inside the purification rack (401). The handles (403) are elastically connected to the inner wall of the cavity (402) through the elastic element (404). The interior of the support airbag (407) is connected to the interior of the two expansion airbags (410) through the ventilation groove (409). The side of the support airbag (407) away from the ventilation groove (409) is fixedly connected to the side of the slider (408) near the ventilation groove (409). The side of the locking block (405) away from the slider (408) is provided with an inclined surface.

10. The oxygen content circulating gas purification heat treatment furnace according to claim 8, characterized in that, The two sides of the purification rack (401) are fixedly connected to the ends of the cooling pipe (302) and heating pipe (304) away from the heat treatment furnace shell (201), respectively. The interior of the purification rack (401) is connected to the interior of the cooling pipe (302) and heating pipe (304). The size of the protrusion (109) is adapted to the size of the groove (406). The replacement rack (101) is slidably connected to the inner wall of the heat treatment furnace shell (201). The first filter screen (104) is located inside the purification rack (401) on the side close to the cooling pipe (302).

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