A return air chamber and pre-oxidation furnace for filter replacement

Abstract

This invention specifically relates to a return air chamber and a pre-oxidation furnace for filter replacement. The return air chamber includes: an unwinding mechanism (10), an unwinding sealing shell (20), a winding mechanism (30), a winding sealing shell (40), and a return air chamber body (60). The winding mechanism (30) is housed in the winding sealing shell (40), and the unwinding mechanism (10) is housed in the unwinding sealing shell (20). Meanwhile, the winding sealing shell (40) and the unwinding sealing shell (20) are respectively disposed on both sides of the return air chamber body (60). When the winding mechanism winds up the return air filter (50) that needs to be replaced, the unwinding mechanism (10) unwinds the temporarily stored return air filter (50) under the drive of the winding mechanism (30), thereby realizing the replacement of the return air filter (50) in the return air chamber body (60). By improving and designing the return air chamber structure, the replacement efficiency of the return air filter can be increased, while ensuring that the stability of the circulating airflow field and the uniformity of temperature are not disrupted during the winding and unwinding process of the return air filter.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber production, and more specifically to a return air chamber and a pre-oxidation furnace for filter replacement. Background Technology

[0002] Carbon fiber is a fibrous carbon material containing over 90% carbon. It is produced by carbonizing various organic fibers under an inert gas atmosphere at high temperatures. With the increasing maturity of carbon fiber manufacturing technology, the current manufacturing process mostly involves two steps: first, manufacturing the precursor fiber; and second, pre-oxidizing and carbonizing the precursor fiber. The purpose of the pre-oxidation treatment is to transform the linear molecular chains of the precursor fiber into a heat-resistant trapezoidal structure, ensuring it does not melt or burn during high-temperature carbonization and maintains its fibrous state.

[0003] Meanwhile, the pre-oxidation treatment of carbon fibers typically employs a pre-oxidation furnace. In the current carbon fiber manufacturing field, pre-oxidation furnaces are mostly classified into cross-flow, horizontal-flow, and co-flow types. The horizontal-flow carbon fiber pre-oxidation furnace is equipped with a fiber bundle channel, with an inlet air chamber and a return air chamber at each end. The internal flow field, after being heated, enters the fiber bundle channel through the inlet air chamber, then reaches the return air chamber. The return air chamber circulates under the negative pressure created by a circulating fan, and after being heated, flows back to the inlet air chamber, thus forming a flow field circulation. However, carbon fibers are prone to producing fuzz during the pre-oxidation process, which can affect subsequent pre-oxidation during circulation. Therefore, a return air filter is installed at the return air chamber to collect the fuzz from the pre-oxidation process, preventing it from affecting the pre-oxidation treatment of the carbon fibers.

[0004] To ensure uniform temperature and stable flow velocity in the carbon fiber pre-oxidation process, the return air chamber and fiber bundle channel of the pre-oxidation furnace are located in the same enclosed space. However, the existing return air filter in the return air chamber uses a pull-out structure for replacement. Therefore, during furnace operation, if the return air filter fails to collect the fiber bundles, it must be replaced without shutting down the furnace. Because the return air filter is pulled out of the return air chamber, external cold air is easily drawn into the pre-oxidation furnace due to the pressure difference, causing turbulence in the fiber bundle channel and thus reducing the quality of the carbon fiber pre-oxidation process. It should be noted that shutting down to replace the return air filter will affect the timeliness of the carbon fiber pre-oxidation process, leading to a decrease in carbon fiber production capacity.

[0005] In addition, due to the high temperature inside the pre-oxidation furnace, the pull-out type of return air filter replacement structure is affected by the high temperature, which can easily cause thermal deformation of the pull-out track, leading to jamming during the return air filter replacement process and delaying the production schedule. Summary of the Invention

[0006] According to the existing technology, the pre-oxidation furnace adopts a pull-out type structure for replacing the return air filter, which easily affects the quality of carbon fiber and is prone to thermal deformation and jamming. The present invention provides a return air chamber and a pre-oxidation furnace for replacing the return air filter.

[0007] First aspect

[0008] The present invention provides a return air cavity for replacing return air filters, the return air cavity comprising: an unwinding mechanism, an unwinding sealing shell, a winding mechanism, a winding sealing shell, and a return air cavity body;

[0009] The winding mechanism is housed in the winding sealing shell, and the unwinding mechanism is housed in the unwinding sealing shell; meanwhile, the winding sealing shell and the unwinding sealing shell are respectively disposed on both sides of the return air cavity;

[0010] When the winding structure winds up the return air filter that needs to be replaced, the unwinding mechanism, driven by the winding mechanism, unwinds the temporarily stored return air filter to be replaced, thereby realizing the replacement of the return air filter in the return air cavity.

[0011] Specifically, one aspect of this invention is the use of a winding method to replace the return air filter. The return air chamber provided by this invention includes an unwinding mechanism and a winding mechanism. The unwinding mechanism temporarily stores clean return air filters to be replaced, while the winding mechanism winds up expired return air filters. The cooperation between the winding and unwinding mechanisms enables quick replacement of the return air filter. Another aspect of this invention is that the winding and unwinding mechanisms are respectively housed within a winding sealing shell and an unwinding sealing shell, thereby isolating the interaction of internal and external air during the winding of the return air filter and preventing changes in the uniformity of the circulating air temperature and the flow field. In fact, it's understandable that switching from a pull-out return air filter replacement method to a roll-up return air filter replacement method has a significant drawback. During normal equipment operation, the pull-out return air filter replacement method places the pull-out box directly inside the return air cavity, essentially making it a sealed unit with the return air cavity, thus not affecting the uniformity and stability of the circulating air temperature. However, its drawback is that it easily introduces cold air during replacement without shutting down the machine, causing turbulence in the circulating air flow field. On the other hand, if the roll-up return air filter replacement method provided by this invention is adopted, since the roll-up and roll-down mechanisms are located outside the return air cavity, there is a risk of cold air intrusion. Therefore, the winding sealing shell and the unwinding sealing shell are used to ensure the sealing of the winding mechanism and the unwinding mechanism respectively, and to isolate them from contact with the outside cold air. This prevents cold air from entering the return air cavity during the winding and unwinding process, causing turbulence in the flow field and changes in temperature uniformity. That is, the solution provided in this embodiment is to improve the replacement of the return air filter by providing a sealed winding and unwinding mechanism. Under the premise of ensuring the stability of the flow field and temperature uniformity in the return air cavity, the return air filter can be replaced conveniently, thereby ensuring the quality and efficiency of carbon fiber in the pre-oxidation process.

[0012] It is understandable that this invention opts for external winding and unwinding mechanisms without increasing the complexity of the mechanical structure. This is because the winding mechanism can only store a limited number of clean return air filters, which need to be replaced when used up, while the unwinding mechanism collects expired return air filters with lint, requiring the avoidance of contamination of the return air cavity. However, based on this concept, with the support of electrically controllable mechanisms and autonomous return air filter replacement technology, it is also possible to choose to internalize the winding and unwinding mechanisms (requiring a balance between cost and mechanical complexity).

[0013] In yet another possible embodiment of the first aspect, a guide groove is provided inside the return air cavity;

[0014] The unwinding mechanism includes an unwinding shaft and a first filter screen guide rod; the winding mechanism includes a winding shaft and a second filter screen guide rod.

[0015] When the return air filter is wound up and replaced, the return air filter is wound into the take-up shaft in sequence via the unwinding shaft, the first filter guide rod, the guide groove, and the second filter guide rod; wherein, the first filter guide rod, the guide groove, and the second filter guide rod keep the return air filter flush in the return air cavity.

[0016] Specifically, the design of replacing the return air filter using a roll-up / unroll method presents several challenges. Besides the risk of cold air entering, the filter's rolling freedom can lead to vibration issues. Existing pull-out return air filter replacement methods allow the pull-out plate to fix the filter's freedom of movement. However, the roll-up / unroll method used in this invention, lacking a fixed support, causes vibration and bending during airflow, potentially disrupting the airflow. Therefore, this embodiment utilizes the guiding and restricting functions of the first filter guide rod, guide groove, and second filter guide rod to prevent significant vibration during roll-up, thus avoiding airflow disruption. The guide groove serves as the guide track and restricts the radial freedom of the return air filter. Furthermore, to prevent heat-induced jamming, the guide groove has a pre-set radial allowance. The first and second filter guide rods provide support and orientation along the guide groove. In fact, if the take-up and unwind shafts directly guide the return air filter, it may cause the return air filter to shrink and loosen, which is not conducive to the filtration of the filament bundle and the stability of the circulating airflow field.

[0017] In another possible embodiment of the first aspect, the take-up shaft and the second filter guide rod are provided with a drive chain, the first filter guide rod and the second filter guide rod are provided with a first driven chain, and the first filter guide rod and the unwind shaft are provided with a second driven chain.

[0018] Specifically, since the return air filter passes through five traveling parts—the winding shaft, the second filter guide rod, the guide groove, the first filter guide rod, and the unwinding shaft—it may undergo thermal deformation due to the heat brought by the circulating air, causing the return air filter to jam during the winding and replacement process. Therefore, this embodiment uses a transmission chain, a first driven chain, and a second driven chain to link the above mechanisms, thereby eliminating the impact of jamming factors and maintaining the smoothness of the return air filter during the winding and replacement process.

[0019] In another possible embodiment of the first aspect, the first driven chain is concealed below the guide groove and spaced apart from the guide groove.

[0020] Specifically, since the unwinding shaft and the first filter guide rod are housed in the unwinding sealing shell, and the winding shaft and the second filter guide rod are housed in the winding sealing shell, the transmission chain and the second driven chain do not need to be protected. However, since the first transmission chain spans the entire return air cavity, in order to avoid affecting the filtration effect of the return air filter and the complexity of the mechanism, it is often used as a concealed mechanism, hidden below the guide groove.

[0021] In yet another possible embodiment of the first aspect, the winding mechanism further includes a pressure plate, a first connecting rod, a second connecting rod, and a rotating shaft;

[0022] One end of the pressure plate is connected to the second filter screen guide rod, and the other end is connected to the first connecting rod;

[0023] The second connecting rod is fixedly connected to the door switch of the winding sealing shell;

[0024] The rotating shaft is connected to the free ends of the first connecting rod and the second connecting rod respectively, so as to realize the transmission between the two;

[0025] When the door switch is opened, the second filter guide rod is disengaged from the working state under the transmission action of the first connecting rod, the rotating shaft and the second connecting rod.

[0026] When the door switch is closed, the second filter guide rod is driven into working state by the transmission action of the first connecting rod, the rotating shaft and the second connecting rod.

[0027] Specifically, supported by the first and second filter guide rods, the return air filter is in a tensioned state within the structure. Therefore, in this embodiment, the door switch of the retractable sealing shell is linked to the second filter guide rod. When the door switch is open, the filter is relaxed under the action of the second filter guide rod, facilitating the replacement of the return air filter; when the door switch is closed, the filter is pressed down under the action of the second filter guide rod, ensuring that the return air filter remains in a tensioned state within the return air chamber.

[0028] In another possible embodiment of the first aspect, multiple sets of filter fixing rods are symmetrically arranged on both sides of the guide groove in the return air cavity.

[0029] Specifically, due to the excessive length and width of the return air filter within the return air cavity, multiple sets of filter fixing rods are used to radially fix the return air filter within the guide groove, thus preventing the vibration of the return air filter from affecting the circulating airflow field.

[0030] In another possible embodiment of the first aspect, the unwinding shaft is secured by a detachable pin disposed outside the unwinding sealing housing.

[0031] Specifically, the detachable pin is used for removing the unwinding spool.

[0032] In another possible embodiment, the take-up shaft is secured by a detachable handle disposed outside the take-up sealing housing, which also provides a manual rotation function.

[0033] In another possible embodiment of the first aspect, a diversion channel is provided between the winding sealing shell and the return air cavity, the diversion channel being located before the circulating air passes through the return air filter.

[0034] Before the circulating air blows towards the return air filter, it enters the winding sealing shell through the diversion channel.

[0035] Specifically, although the winding seal effectively separates the air inside and outside the return air chamber, the recirculated air can enter through the return air filter at the outlet of the winding seal, causing convection at this inlet and outlet. Therefore, a diversion channel is used to achieve a small circulation of the recirculated air within the winding seal, preventing the airflow directions between the return air chamber and the winding seal from clashing and causing turbulence in the recirculated air. Furthermore, the diversion channel also ensures temperature uniformity between the winding seal and the return air chamber, thus preventing the exchange of hot and cold air during unwinding from affecting the uniformity of the flow field temperature.

[0036] In another possible embodiment of the first aspect, a confluence channel is provided between the unwinding sealing shell and the return air cavity, the confluence channel being located after the circulating air passes through the return air filter.

[0037] When the circulating air enters the unwinding sealing shell through the opening for the movement of the return air filter, it will then enter the return air cavity through the confluence channel.

[0038] Specifically, the function of the confluence channel in the unwinding sealing shell is similar to that of the diversion channel in the winding sealing shell, and will not be elaborated further here. In fact, the winding and unwinding sealing shells are positioned relative to the return air filter to ensure the smoothness of the winding process and avoid the problem of the return air filter getting stuck due to winding on the same side.

[0039] In a second aspect, the present invention provides a pre-oxidation furnace, including any of the possible return air chambers described in the first aspect above.

[0040] Specifically, the return air cavity provided by this invention is mainly used to improve the replacement method of the return air filter of the pre-oxidation furnace, and its main application is the pre-oxidation furnace for producing carbon fiber.

[0041] In summary, this invention provides a return air chamber and pre-oxidation furnace for replacing return air filters. Due to the adoption of a retractable return air filter replacement method and the balancing and sealing design of the circulating air, it has at least the following advantages: 1. It improves the replacement efficiency of the return air filter, thereby increasing the production capacity of carbon fiber pre-oxidation treatment; 2. The sealed structure improves the defects of the existing pull-out return air filter replacement method, which is prone to flow field turbulence and temperature uniformity changes, thus improving the quality of pre-oxidation treatment. Attached Figure Description

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0043] Figure 1 A schematic diagram of a return air chamber for filter replacement provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the unwinding mechanism provided in this embodiment of the invention;

[0045] Figure 3 A schematic diagram of the winding mechanism provided in this embodiment of the invention;

[0046] Figure 4 A schematic diagram of the opening and closing structure of the winding mechanism provided in this embodiment of the invention;

[0047] 10. Unwinding mechanism; 20. Unwinding sealing shell; 30. Rewinding mechanism; 40. Rewinding sealing shell; 50. Return air filter; 60. Return air cavity; 70. Fiber bundle channel; 11. Unwinding shaft; 12. First filter guide rod; 21. Unwinding orientation opening; 31. Rewinding shaft; 32. Second filter guide rod; 33. Rotary handle; 34. Pressure plate; 35. First connecting rod; 36. Rotary shaft; 37. Second connecting rod; 38. Door switch; 41. Rewinding orientation opening; 61. Guide groove; 62. Filter fixing rod. Detailed Implementation

[0048] The following is in conjunction with the appendix Figures 1 to 4 The present invention will be described in detail below.

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] Please see Figure 1 As shown, Figure 1 This invention provides a schematic diagram of a return air chamber for filter replacement.

[0051] Specifically, the return air cavity provided in this embodiment includes an unwinding mechanism 10, an unwinding sealing shell 20, a winding mechanism 30, a winding sealing shell 40, and a return air cavity body 60. The unwinding mechanism 10 is housed inside the unwinding sealing shell 20, and the winding mechanism 30 is housed inside the winding sealing shell 40. The unwinding sealing shell 20 and the winding sealing shell 40 are respectively disposed on both sides of the return air cavity body 60. The unwinding opening of the return air filter 50 of the unwinding sealing shell 20 and the winding opening of the return air filter 50 of the winding sealing shell 40 face inward to achieve the connection of the three components.

[0052] The winding mechanism 30 is used to temporarily store clean return air filters 50, while the unwinding mechanism 10 is used to temporarily store returned air filters 50 that have failed to filter properly. Return air filters 50 in operation are placed inside the return air cavity 60. However, when the carbon fiber pre-oxidation treatment detection mechanism detects an increase in fuzz or a decline in the quality of the carbon fiber pre-oxidation treatment, it will issue a warning that the return air filters 50 need to be replaced. At this time, the winding mechanism 30 winds up the return air filters 50, and the unwinding mechanism 10 simultaneously unwinds them under the drive of the winding mechanism 30, thus completing the replacement of the return air filters 50 inside the return air cavity 60 and improving the filter replacement efficiency. Simultaneously, since the unwinding sealing shell 20 and the winding sealing shell 40 are enclosed by insulation panels, the unwinding sealing shell 20, the return air cavity 60, and the winding sealing shell 40 form a single insulated unit, preventing heat exchange with the outside cold air. This ensures that the flow field of the circulating air is not disrupted during the replacement of the return air filters 50, guaranteeing a stable flow field and uniform temperature in the circulating air.

[0053] In yet another possible embodiment, the return air chamber provided in this embodiment is applied to a multi-layer pre-oxidation furnace. See Figure 1 As shown, the return air chamber 60 is arranged in multiple layers with gaps between the upper and lower layers. A fiber bundle channel 70 is provided within the gaps between the upper and lower layers, so that the circulating air, after being filtered by the return air filter 50 after passing through the return air chamber 60, recirculates into the fiber bundle channel 70. This multi-layered pre-oxidation furnace design improves the efficiency of carbon fiber pre-oxidation treatment.

[0054] It is worth noting that the structural design of the return air cavity provided by the present invention is very suitable for this multi-layer pre-oxidation furnace, and can be directly arranged in groups on both sides of the return air cavity body 60.

[0055] In another possible embodiment, a guide groove 61 is provided opposite to the position where the return air filter 50 is located in the single-layer return air cavity 60. The guide groove 61 restricts the axial and radial degrees of freedom of the return air filter 50. In fact, the guide groove 61 will be used in conjunction with the first filter guide rod 12 and the second filter guide rod 32, see Figure 2 and Figure 3 As shown. The unwinding mechanism 10 includes an unwinding shaft 11 and a first filter guide rod 12. Clean return air filter 50 is temporarily stored on the unwinding shaft 11 by winding. The winding mechanism 30 includes a winding shaft 31 and a second filter guide rod 32. The wound-up filter is temporarily stored on the winding shaft 31. When the return air filter 50 needs to be replaced due to filtration failure, the winding shaft 31 rotates to drive the winding of the return air filter 50. The first filter guide rod 12, the second filter guide rod 32, and the guide groove 61 provide support, guidance, and directional restriction for the return air filter 50, ensuring that the return air filter 50 does not curl or vibrate significantly during the winding and replacement process, thus ensuring the stability of the circulating air flow field and the uniformity of temperature. It is important to understand that if the return air filter 50 vibrates and bends within the return air cavity 60 during replacement, it will affect the collection of the filaments. Furthermore, the flow of the circulating air will cause the return air filter 50 to vibrate back and forth within the return air cavity 60, resulting in turbulence in the airflow field and disruption of temperature uniformity. In addition, the first filter guide rod 12 and the second filter guide rod 32 also serve to tighten the return air filter 50.

[0056] In another possible embodiment, the take-up shaft 31 and the second filter guide rod 32 are provided with a drive chain, the first filter guide rod 12 and the second filter guide rod 32 are provided with a first driven chain, and the first filter guide rod 12 and the unwind shaft 11 are provided with a second driven chain.

[0057] Specifically, since the return air filter 50 travels through five parts—the winding shaft 31, the second filter guide rod 32, the guide groove 61, the first filter guide rod 12, and the unwinding shaft 11—it may undergo thermal deformation due to the heat brought by the circulating air, causing the return air filter 50 to jam during the winding and replacement process. Therefore, this embodiment uses a transmission chain, a first driven chain, and a second driven chain to link the above mechanisms, thereby eliminating the impact of jamming factors and maintaining the smoothness of the return air filter 50 during the winding and replacement process.

[0058] In reality, the return air filter 50's degrees of freedom are restricted by the first filter guide rod 12, the second filter guide rod 32, and the guide groove 61. Although the guide groove 61 has a pre-set radial width for the sliding of the return air filter 50, due to the high temperature inside the return air cavity, the return air filter 50 may experience thermal deformation, and coupled with the supporting effect of the first filter guide rod 12 and the second filter guide rod 32, jamming may occur. Therefore, this embodiment achieves linkage between the winding shaft 31, the first filter guide rod 12, the second filter guide rod 32, and the unwinding shaft 11 through the action of the transmission chain, the first driven chain, and the second driven chain, thereby ensuring the smoothness of the return air filter 50 during the winding process and improving the reliability of the mechanical structure.

[0059] In another possible embodiment, the first driven chain is concealed below the guide groove 61 and spaced apart from the guide groove 61.

[0060] Specifically, since the unwinding shaft 11 and the first filter guide rod 12 are housed in the unwinding sealing shell 20, and the winding shaft 31 and the second filter guide rod 32 are housed in the winding sealing shell 40, the transmission chain and the second driven chain do not need to be protected. However, since the first transmission chain spans the entire return air cavity 60, in order to avoid affecting the filtration effect of the return air filter 50 and the complexity of the mechanism, it is usually a concealed mechanism hidden below the guide groove 61.

[0061] In fact, the first driven chain spans the entire return air cavity 60, and adopts a concealed design without affecting the filtration integrity of the return air filter 50 and the contact area of ​​the circulating air.

[0062] In another possible embodiment, the first driven chain is replaced with a circulating ball bearing. Although the first driven chain can achieve transmission between the first filter guide rod 12 and the second filter guide rod 32, it will compress the volume of the fiber bundle channel 70. Therefore, in this embodiment, the space occupied by the transmission of the first filter guide rod 12 and the second filter guide rod 32 by the ball bearing makes the overall structure design of the return air cavity more reasonable.

[0063] In another possible embodiment, multiple sets of filter fixing rods 62 are symmetrically arranged on both sides of the guide groove 61 of the return air cavity 60, see Figure 1 As shown.

[0064] Specifically, in this embodiment, considering the radial width reserved in the guide groove 61, when the overall return air filter 50 is too long in the return air cavity 60, it is inevitable that it will become loose and vibrate back and forth. The filter fixing rod 62 is used to maintain the straightness of the return air filter 50 in the return air cavity 60, so as to avoid large vibrations affecting the stability of the circulating airflow field and the temperature uniformity.

[0065] Please see Figure 2 As shown, Figure 2 A schematic diagram of the unwinding mechanism 10 provided in this embodiment of the invention.

[0066] Specifically, the unwinding sealing shell 20 is composed of a square-sealed insulation board, with its unwinding opening 21 facing the return air cavity 60. For clarity, the insulation board at the unwinding sealing shell 20 has been removed. In reality, the unwinding sealing shell 20 only has an opening at the passage of the return air filter 50 for unwinding the return air filter 50.

[0067] In yet another possible embodiment, a diversion channel is provided between the winding sealing shell 40 and the return air cavity 60, the diversion channel being located before the circulating air passes through the return air filter 50.

[0068] Before the circulating air blows toward the return air filter 50, it enters the winding sealing shell 40 through the diversion channel.

[0069] Specifically, although the winding sealing shell 40 separates the air inside and outside the return air cavity 60, the recirculated air can enter through the return air filter 50 at the outlet of the winding sealing shell 40, causing convection at this inlet and outlet. Therefore, a small circulation of the recirculated air within the winding sealing shell 40 is achieved through a diversion channel, preventing the airflow direction between the return air cavity and the winding sealing shell 40 from conflicting and causing turbulence in the recirculated air. In addition, the diversion channel also ensures temperature uniformity between the winding sealing shell 40 and the return air cavity 60, thus avoiding the exchange of hot and cold air during unwinding from affecting the uniformity of the flow field temperature.

[0070] In practice, the return air filter 50 is wound up through an opening in the winding sealing shell 40 and the return air cavity 60. Because of this opening, circulating air enters and exits along it, causing convection and heat exchange, which may affect the stability of the airflow field and the temperature uniformity of the circulating air. Therefore, a flow-diverting channel is provided on the opposite side of the winding-up opening 41 of the winding sealing shell 40 and the second filter guide rod 32, allowing circulating air to enter the winding sealing shell 40. This ensures the temperature consistency between the winding sealing shell 40 and the return air cavity 60, thus avoiding temperature changes during air exchange. Furthermore, the flow-diverting channel forms a loop with the opening in the winding sealing shell 40 for winding up the return air filter 50, ensuring the stability of the airflow field in the return air cavity 60 during airflow exchange with the winding sealing shell 40.

[0071] Furthermore, the flow rate of the diversion channel is consistent with the flow rate of the opening at the winding sealing shell 40 used for winding the return air filter 50, in order to ensure the flow balance of the air circulation of the winding sealing shell.

[0072] Furthermore, a winding filter screen is also provided inside the winding sealing shell 40 to separate the wound return air filter screen from the diversion channel and the opening for winding the return air filter screen 50, so as to prevent the lint collected by the wound filter screen from being pulled out when the winding sealing shell is circulating air, thus causing pollution to the return air cavity.

[0073] In another possible embodiment, a confluence channel is provided between the unwinding sealing shell 20 and the return air cavity 60. The confluence channel is located after the circulating air passes through the return air filter 50. When the circulating air enters the unwinding sealing shell 20 through the opening of the unwinding sealing shell 20 for the movement of the return air filter 50, it will then pass through the confluence channel into the return air cavity 60.

[0074] Specifically, the function of the merging channel in the unwinding sealing shell 20 is similar to that of the diverting channel in the winding sealing shell 40, and will not be elaborated here.

[0075] Furthermore, the flow rate of the merging channel is consistent with the flow rate of the opening of the unwinding sealing shell 20 for unwinding the return air filter, in order to ensure the flow balance of the air circulation of the unwinding sealing shell.

[0076] Furthermore, an unwinding filter screen is also provided inside the unwinding sealing shell 20 to separate the unwinding return air filter screen from the confluence channel and the opening for unwinding the return air filter screen 50, so as to prevent the lint in the return air cavity from entering the unwinding return air filter screen 50 when the unwinding sealing shell is circulating air, thus preventing contamination of the clean return air filter screen 50.

[0077] It is worth noting that the winding sealing shell 40 and the unwinding sealing shell 20 are positioned relative to the return air filter 50 to ensure smooth winding and prevent the return air filter 50 from jamming due to winding on the same side. The configuration of the merging and branching channels depends primarily on the positions of the winding sealing shell 40 and the unwinding sealing shell 20 relative to the return air filter 50. See [link / reference] Figure 1 As shown, the unwinding sealing shell 20 is located downstream of the circulating air, and therefore has a confluence channel. This allows the circulating air in the return air chamber 60 to enter the unwinding sealing shell 20 through the opening at the first filter guide rod 12, and then circulate back into the return air chamber 60 through the confluence channel. The winding sealing shell 40 is located upstream of the circulating air, and therefore has a diversion channel. This allows the circulating air in the return air chamber 60 to enter the winding sealing shell 40 through the diversion channel, and then circulate back into the return air chamber 60 through the opening of the return air filter 50 at the second filter guide rod 32.

[0078] In another possible embodiment, the unwinding sealing housing 20 includes a sealing door opened on either side of the return air chamber 60, and a removable latch. When the filter needs to be replaced, the unwinding shaft 11 is removed from the sealing door via the removable latch, thereby rewinding the return air filter 50.

[0079] Please see Figure 3 As shown, Figure 3 A schematic diagram of the winding mechanism 30 provided in this embodiment of the invention.

[0080] Specifically, the winding mechanism 30 has a similar structure to the unwinding mechanism 10, including a winding sealing shell 40, whose winding orientation opening 41 faces the return air cavity 60.

[0081] In another possible embodiment, the take-up shaft 31 is secured by a detachable handle 33 disposed outside the take-up sealing housing 40, and the handle 33 also provides a manual rotation function. The handle 33 is detachable, facilitating the removal of the take-up shaft 31 from the door switch 38.

[0082] In another possible embodiment, the winding mechanism 30 further includes a pressure plate 34, a first connecting rod 35, a second connecting rod 37, and a rotating shaft 36. When the door switch 38 is opened, the second filter screen guide rod 32 is disengaged from the working state under the transmission action of the first connecting rod 35, the rotating shaft 36, and the second connecting rod 37. When the door switch 38 is closed, the second filter screen guide rod 32 is engaged in the working state under the transmission action of the first connecting rod 35, the rotating shaft 36, and the second connecting rod 37.

[0083] Specifically, supported by the first filter guide rod 12 and the second filter guide rod 32, the return air filter 50 is in a tensioned state within the structure. Therefore, in this embodiment, the door switch 38 of the winding sealing shell 40 is linked to the second filter guide rod 32. When the door switch 38 is opened, it is relaxed under the action of the second filter guide rod 32, thus facilitating the replacement of the return air filter 50; when the door switch 38 is closed, it is pressed tight under the action of the second filter guide rod 32, thereby ensuring that the return air filter 50 is in a tensioned state within the return air cavity. Figure 4 In the open / closed state, Figure 3 It is in a taut state.

[0084] In another possible implementation, the present invention provides a pre-oxidation furnace comprising any of the possible return air chambers described in the first aspect above.

[0085] Specifically, the return air cavity provided by this invention is mainly used to improve the replacement method of the return air filter 50 of the pre-oxidation furnace, and its main application is the pre-oxidation furnace for producing carbon fiber.

[0086] In fact, the present invention can also be used in the modification project of the return air cavity of the pre-oxidation furnace. By modifying the return air cavity structure of the pre-oxidation furnace according to the present invention, the replacement efficiency of the return air filter 50 can be improved, and the flow field stability and uniformity of the pre-oxidation furnace can be guaranteed.

[0087] The present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the invention and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A return air chamber for filter replacement, characterized in that, For use in a pre-oxidation furnace, the return air chamber includes: an unwinding mechanism (10), an unwinding sealing shell (20), a winding mechanism (30), a winding sealing shell (40), and a return air chamber body (60). The winding mechanism (30) is housed in the winding sealing shell (40), and the unwinding mechanism (10) is housed in the unwinding sealing shell (20); meanwhile, the winding sealing shell (40) and the unwinding sealing shell (20) are respectively disposed on both sides of the return air cavity (60); When the winding mechanism winds up the return air filter (50) that needs to be replaced, the unwinding mechanism (10) unwinds the temporarily stored return air filter (50) under the drive of the winding mechanism (30), thereby realizing the replacement of the return air filter (50) in the return air cavity (60). The return air cavity (60) is provided with a guide groove (61); The unwinding mechanism (10) includes an unwinding shaft (11) and a first filter guide rod (12); the winding mechanism (30) includes a winding shaft (31) and a second filter guide rod (32). When the return air filter (50) is wound up and replaced, the return air filter (50) is wound into the take-up shaft (31) in sequence via the unwinding shaft (11), the first filter guide rod (12), the guide groove (61), and the second filter guide rod (32); wherein the first filter guide rod (12), the guide groove (61), and the second filter guide rod (32) keep the return air filter (50) flush within the return air cavity (60); The winding mechanism (30) also includes a pressure plate (34), a first connecting rod (35), a second connecting rod (37), and a rotating shaft (36). One end of the pressure plate (34) is connected to the second filter screen guide rod (32), and the other end is connected to the first connecting rod (35); The second connecting rod (37) is fixedly connected to the door switch (38) of the winding sealing shell (40); The rotating shaft (36) is connected to the free ends of the first connecting rod (35) and the second connecting rod (37) respectively, so as to realize the transmission between the two; When the door switch (38) is opened, the second filter screen guide rod (32) is driven to disengage from the working state under the transmission action of the first connecting rod (35), the rotating shaft (36) and the second connecting rod (37); When the door switch (38) is closed, the second filter guide rod (32) is driven into working state by the transmission action of the first connecting rod (35), the rotating shaft (36) and the second connecting rod (37); A diversion channel is provided between the winding sealing shell (40) and the return air cavity (60), and the diversion channel is provided before the circulating air passes through the return air filter (50); Before the circulating air blows toward the return air filter (50), it enters the winding sealing shell (40) through the diversion channel. A confluence channel is provided between the unwinding sealing shell (20) and the return air cavity (60), and the confluence channel is located after the circulating air passes through the return air filter (50); When the circulating air enters the unwinding sealing shell (20) through the opening for the movement of the return air filter (50), it will then enter the return air cavity (60) through the confluence channel.

2. The return air chamber for filter replacement as described in claim 1, characterized in that, The take-up shaft (31) and the second filter guide rod (32) are provided with a transmission chain, the first filter guide rod (12) and the second filter guide rod (32) are provided with a first driven chain, and the first filter guide rod (12) and the unwind shaft (11) are provided with a second driven chain.

3. The return air chamber for filter replacement as described in claim 2, characterized in that, The first driven chain is hidden below the guide groove (61) and separated from the guide groove (61).

4. The return air chamber for filter replacement as described in claim 1, characterized in that, Multiple sets of filter fixing rods (62) are symmetrically arranged on both sides of the guide groove (61) inside the return air cavity (60).

5. The return air chamber for filter replacement as described in claim 1, characterized in that, The unwinding shaft (11) is fixed by a detachable pin located outside the unwinding sealing shell (20).

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