Carbon fiber low-temperature carbonization furnace

Abstract

A carbon fiber low-temperature carbonization furnace comprises a furnace body and a sealing chamber. A gas distribution pipe set is arranged in the sealing chamber and comprises two gas distribution pipes distributed on the upper side and the lower side of the tow channel, each gas distribution pipe comprises a gas guide pipe allowing shielding gas to pass through and a gas guide shell arranged on the outer side of the gas guide pipe, and each gas guide shell is formed by an arc-shaped plate and two plane plates to be in a U shape; a gas guide groove is formed in the opening side of the gas guide shell and faces the tow channel, the gas guide shell capable of homogenizing airflow beams is arranged on the outer side of the gas guide pipe, airflow of multiple beams of shielding gas uniformly forms an airflow curtain in the width direction of the fiber beams, a uniform sealing barrier is achieved, and therefore the shielding effect is improved. According to the carbonization furnace, external oxygen can be prevented from entering the carbonization furnace cavity, an oxygen-free environment in the carbonization furnace cavity is ensured, and the phenomenon that shielding gas is densely distributed at the outlets of the holes and the areas among the holes are relatively thin can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon fiber carbonization, and specifically refers to a carbon fiber low-temperature carbonization furnace. Background Art

[0002] Low-temperature carbonization of carbon fiber refers to heat treatment of carbon fiber at a certain temperature so that it is gradually converted into carbide under oxygen-free conditions. During the low-temperature carbonization of carbon fiber, the ladder structure of the pre-oxidized fiber (PAN precursor that has been pre-oxidized) undergoes pyrolysis to cause the non-carbon atoms to escape and undergo a condensation reaction to generate a chaotic layer graphite structure or a graphite structure, and finally generates an inorganic carbon fiber with a carbon content of more than 92%. Since it is crucial that the carbonization process of carbon fiber is not oxidized, the oxygen in the air will cause the carbon fiber to be oxidized during the carbonization process, thereby affecting its quality and performance. Therefore, the inlet and outlet of the carbonization furnace will be equipped with a labyrinth sealing device, which can prevent air from entering the furnace and ensure an oxygen-free environment.

[0003] The sealing device transports the protective gas through a pipeline, guides the protective gas to the channel through which the carbon fiber passes, and blocks the air that enters with the carbon fiber to the outside to prevent the air from entering the furnace. At present, the protective gas is generally transported by a plate or tube with holes to guide the gas vertically from the upper and lower sides of the carbon fiber to the channel. Due to the gaps between the air guide holes, the distribution of the protective gas supply is uneven, so there will be a problem of uneven distribution of the protective gas in the sealed room, which will affect the protective effect of the protective gas on the carbon fiber filaments. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention creatively adopts a carbon fiber low-temperature carbonization furnace to at least partially solve the problems raised in the above background technology.

[0005] The technical solution adopted is as follows: The present invention proposes a carbon fiber low-temperature carbonization furnace, comprising: A furnace body, wherein two groups of heaters are arranged in the furnace body, and the two groups of heaters are respectively distributed on the upper and lower sides of the carbonization furnace chamber; A sealed chamber is arranged at the entrance and exit of the carbonization furnace chamber, and a fiber bundle passage is provided in the sealed chamber for the fiber bundle to pass through; A traction roller group is arranged at the front and rear sides of the sealing chamber and is used for traction and conveying the fiber bundle; an exhaust fan, disposed at the top of the furnace body and configured to extract gas from the top of the carbonization furnace chamber; an air supply fan, disposed at the bottom of the furnace body and configured to provide protective gas from the bottom of the carbonization furnace chamber; Among them, an air distribution pipe group is provided inside the sealed chamber, and the air distribution pipe group includes two groups of air distribution pipes distributed on the upper and lower sides of the wire bundle channel, and the air distribution pipe includes an air guide pipe for protective gas to pass through and an air guide shell arranged on the outside of the air guide pipe, and the air guide shell is constructed into a "U" shape by an arc plate and two flat plates, and an air guide groove is provided on the open side of the air guide shell, and the air guide groove faces the wire bundle channel, the air guide pipe and the arc plate are distributed in concentric circles, and an air guide hole is provided on the air guide pipe, and the air guide hole faces the arc plate, so that the protective gas in the air guide pipe is discharged from the air guide hole, and then returned through the guide of the air guide shell and introduced into the wire bundle channel from the air guide groove.

[0006] Furthermore, along the axial direction of the air guide tube, a plurality of air guide holes are equidistantly provided, and one or two air guide holes are provided at the same circumferential position of the air guide tube; when the number of the air guide holes is one, the air guide hole points to the center position of the arc plate; when the number of the air guide holes is two, the two air guide holes point symmetrically to the inner side of the arc plate, and the angle between the two air guide holes is ninety degrees.

[0007] Furthermore, a first air guide fin, a second air guide fin and a third air guide fin are sequentially provided on the inner wall of the air guide shell in the direction from the air guide pipe to the air guide groove, and the first air guide fins are set in multiple groups corresponding to the number and position of the air guide holes, and each group of the first air guide fins is set in multiple groups radially distributed with the air guide hole as the center, and the second air guide fins are arranged in multiple groups equidistantly along the axial direction of the air guide pipe, and one ends of the multiple first air guide fins in the same group intersect at the projection point of the air guide hole on the air guide shell, and the other ends are respectively connected to the second air guide fins at corresponding positions.

[0008] Furthermore, a height of the first air guide fin is less than or equal to a distance between the air guide pipe and the air guide shell.

[0009] Furthermore, more than two third air guide fins are provided on the inner side of the air guide shell corresponding to the second air guide fin and the air guide groove, with the direction from the second air guide fin to the air guide groove being the first direction, and the plurality of third air guide fins are staggeredly distributed on the inner walls of the two flat plates in the first direction, and the third air guide fin has an arc-shaped surface on the side facing the air guide pipe.

[0010] Furthermore, the curvature of the arc-shaped surface increases gradually along the first direction, and the height of the third air guide fin is set to half of the interval between the planar plates.

[0011] Furthermore, an air guide plate is provided on the air guide shell at a position corresponding to the air guide groove, one end of the air guide plate is fixedly connected to the air guide shell, and the other end extends into the fiber bundle channel, the air guide plate is constructed as an arc strip, and the air guide plate guides the airflow in the air guide shell to the direction of the fiber bundle input; A plurality of air distribution pipes are provided in the sealed chamber along the conveying direction of the fiber bundle, and at least one of the air guide shells is provided with the air guide plate. Along the conveying direction of the fiber bundle, the spacing between the plurality of air guide plates and the fiber bundle gradually decreases, and the angle parallel to the fiber bundle is set to 0°. The air flow guide angle of the air guide plate to the air guide groove is in the range of 0°-±45°.

[0012] Furthermore, the sealed chamber is provided with an air supply pipe and an air exhaust pipe, the air supply pipe is connected to the output end of the air supply fan, the air exhaust pipe is connected to the input end of the exhaust fan, the air distribution pipe includes one or more blowing pipe groups and one or more suction pipe groups, the blowing pipe group is connected to the air supply pipe, and the suction pipe group is connected to the air exhaust pipe.

[0013] Furthermore, an exhaust duct is provided on the upper side of the furnace body corresponding to the carbonization furnace chamber, and the exhaust duct is connected to the input end of the exhaust fan. An air supply duct is provided on the lower side of the furnace body corresponding to the carbonization furnace chamber, and the air supply duct is connected to the output end of the air supply fan. A plurality of exhaust pipes are provided on the exhaust duct, and a plurality of supply pipes are provided on the air supply duct, and the exhaust pipes and the air supply pipes are symmetrically distributed up and down.

[0014] Furthermore, the exhaust duct and the air supply duct both include air distribution ducts.

[0015] The beneficial effects achieved by the present invention using the above structure are as follows: By arranging an air guide shell on the outside of the air guide tube that can homogenize the air flow beam, the air flows of multiple shielding gases evenly form an air flow curtain in the width direction of the fiber bundle, thereby achieving a uniform sealing barrier, thereby preventing external oxygen from entering the carbonization furnace chamber, ensuring an oxygen-free environment in the carbonization furnace chamber, and preventing the shielding gas from being densely distributed at the outlet of the hole and relatively thin in the area between the holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the three-dimensional structure of a carbon fiber low-temperature carbonization furnace proposed in an embodiment of the present invention; Figure 2 A schematic diagram of the internal structure of a carbon fiber low-temperature carbonization furnace proposed in an embodiment of the present invention; Figure 3 An enlarged schematic diagram of the internal structure of a sealed chamber is provided for an embodiment of the present invention; Figure 4A partial enlarged structural schematic diagram of a gas distribution pipe according to an embodiment of the present invention; Figure 5 for Figure 4 A schematic cross-sectional structure diagram of ; Figure 6 This is a schematic diagram of the side structure of the air guide casing.

[0017] Among them, 10, furnace body; 100, carbonization furnace chamber; 11, bracket; 12, heater; 20, sealing chamber; 201, fiber bundle channel; 21, air supply pipe; 22, exhaust pipe; 30, exhaust fan; 31, exhaust pipeline; 311, exhaust pipe; 32, exhaust main pipe; 40, air supply fan; 41, air supply pipeline; 411, air supply pipe; 50, traction roller group; 60, air distribution pipe; 600, air guide groove; 601, air blowing pipe group; 602, air suction pipe group; 61, air guide pipe; 610, air guide hole; 611, air blowing pipe; 612, air suction pipe; 62, air guide shell; 621, first air guide fin; 622, second air guide fin; 623, third air guide fin; 63, air guide plate.

[0018] The accompanying drawings are used to provide further understanding of the embodiments and constitute a part of the specification. They are used for explanation together with the embodiments and do not constitute a limitation of the embodiments. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection.

[0020] In the description of the embodiments, it should be understood that terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the embodiments.

[0021] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, a carbon fiber low-temperature carbonization furnace is provided, which aims to improve the uniformity of the sealed internal protective gas to enhance the protective effect of the protective gas on the carbon fiber. The carbonization furnace mainly includes a furnace body 10, a sealed chamber 20, a traction roller group 50, an exhaust fan 30 and an air supply fan 40.

[0022] Among them, a bracket 11 is fixedly arranged at the bottom of the furnace body 10 for supporting the entire furnace body 10. Two groups of heaters 12 are arranged in the furnace body 10, and the two groups of heaters 12 are respectively distributed on the upper and lower sides of the carbonization furnace chamber 100. In some embodiments, the furnace temperature of the low-temperature carbonization furnace is generally designed to be 300°C-800°C, and a temperature gradient is formed from low to high, so that the pyrolysis process is gradual, controllable, adjustable, and smooth. Therefore, the heater 12 is generally divided into 5-6 temperature zones to ensure the uniformity and stability of the carbonization process.

[0023] During the low-temperature carbonization process, the pre-oxidized yarn (PAN raw yarn that has been pre-oxidized) will undergo pyrolysis and polycondensation reactions, producing a large amount of by-product waste gas and tar. These waste gases need to be discharged out of the furnace instantly, otherwise they will contaminate the fibers and affect the quality of the carbon fiber.

[0024] Therefore, in order to timely discharge the waste gas and other impurities generated by the pyrolysis of the pre-oxidized wire, the exhaust fan 30 is arranged at the top of the furnace body 10, and can draw gas from the top of the carbonization furnace chamber 100, and the air supply fan 40 is arranged at the bottom of the furnace body 10, and can provide protective gas from the bottom of the carbonization furnace chamber 100.

[0025] Furthermore, Figure 2 As shown, an exhaust duct 31 is provided on the upper side of the furnace body 10 corresponding to the carbonization furnace chamber 100, and the exhaust duct 31 is connected to the input end of the exhaust fan 30. An air supply duct 41 is provided on the lower side of the furnace body 10 corresponding to the carbonization furnace chamber 100, and the air supply duct 41 is connected to the output end of the air supply fan 40. A plurality of exhaust ducts 311 are provided on the exhaust duct 31, and a plurality of air supply ducts 411 are provided on the air supply duct 41. The exhaust ducts 311 and the air supply ducts 411 are symmetrically distributed up and down.

[0026] Among them, the input end of the air supply fan 40 is connected to the protective gas source, and the protective gas can be nitrogen, argon or other inert gases, which is transported to the air supply pipe 411 arranged below the fiber bundle path through the air supply pipe 41, and discharged upward through the air supply pipe 411, so that the waste gas impurities generated by the pyrolysis of the fiber filaments are blown upward. At the same time, the input end of the exhaust fan 30 is connected to the exhaust pipe 311 distributed above the fiber bundle path through the exhaust pipe 31, and the exhaust pipe 311 is correspondingly arranged above the air supply pipe 411, so as to cooperate in sucking and discharging the waste gas impurities generated by the pyrolysis of the fiber filaments. The output end of the exhaust fan 30 is transported to the exhaust gas emission system through the exhaust main pipe 32 for harmless treatment.

[0027] Furthermore, in order to prevent air from entering the carbonization furnace chamber 100 and ensure an oxygen-free environment in the carbonization furnace chamber 100, a sealed chamber 20 is arranged at the entrance and exit of the carbonization furnace chamber 100, and a fiber bundle channel 201 for the fiber bundle to pass through is provided in the sealed chamber 20, and a traction roller group 50 is arranged on the front and rear sides of the sealed chamber 20 and is used to traction and transport the fiber bundle.

[0028] like Figure 2 , Figure 3 and Figure 4 As shown, an air distribution pipe group is provided inside the sealing chamber 20 , and the air distribution pipe group includes two groups of air distribution pipes 60 distributed on the upper and lower sides of the tow channel 201 .

[0029] Furthermore, the air distribution pipe 60 includes an air guide pipe 61 for the protective gas to pass through and an air guide shell 62 arranged outside the air guide pipe 61. The air guide shell 62 is constructed into a "U" shape by an arc plate and two flat plates, and the opening side of the air guide shell 62 has an air guide groove 600, and the air guide groove 600 faces the filament channel 201.

[0030] Furthermore, the air guide tube 61 and the arc plate are arranged in concentric circles, and an air guide hole 610 is provided on the air guide tube 61, and the air guide hole 610 faces the arc plate, so that the protective gas in the air guide tube 61 is discharged from the air guide hole 610, and then returned by the air guide shell 62 and introduced into the wire bundle channel 201 from the air guide groove 600. In this way, after the protective gas flows out from the multiple air guide holes 610 distributed at intervals on the air guide tube 61, it will contact and diffuse with the air guide shell 62 in advance, and after being guided and diffused by the air guide shell 62, it will flow in the direction of the air guide groove 600 and be discharged from the linear air guide groove 600, so that the protective gas originally unevenly distributed in the layout direction of the air guide tube 61 can be more even.

[0031] At present, when the protective gas is transported to the fiber bundle channel 201 by means of a single perforated plate or tube, the protective gas is densely distributed at the outlet of the holes, while it is relatively thin in the area between the holes, causing the airflow to be uneven. In the present embodiment, an air guide shell 62 capable of homogenizing the airflow beam is arranged on the outer side of the air guide tube 61, so that the airflow of multiple beams of protective gas forms an airflow curtain uniformly in the width direction of the fiber bundle, thereby achieving a uniform sealing barrier, which can prevent external oxygen from entering the carbonization furnace chamber 100 and ensure an oxygen-free environment in the carbonization furnace chamber 100.

[0032] In some embodiments, in order to adjust the ability of the air guide tube 61 to export the amount of shielding gas per unit time, a plurality of air guide holes 610 are equidistantly provided along the axial direction of the air guide tube 61, and one or two air guide holes 610 are provided at the same circumferential position of the air guide tube 61. When the number of the air guide holes 610 is one, the air guide hole 610 points to the center position of the arc plate. When the number of the air guide holes 610 is two, the two air guide holes 610 point symmetrically to the inner side of the arc plate, and the angle between the two air guide holes 610 is ninety degrees. In this way, after the shielding gas flows out from the air guide holes 610, it can flow evenly along the inner wall of the air guide shell 62 toward the air guide groove 600, thereby promoting the uniform distribution of the air flow beam in the length direction of the air guide tube 61.

[0033] like Figure 5 and Figure 6 As shown, further, the inner wall of the air guide shell 62 is provided with a first air guide fin 621, a second air guide fin 622 and a third air guide fin 623 in sequence from the air guide tube 61 to the air guide groove 600, and the first air guide fins 621 are set to multiple groups corresponding to the number and position of the air guide holes 610, and each group of first air guide fins 621 is set to multiple groups in a radially distributed manner with the air guide hole 610 as the center, and multiple second air guide fins 622 are equidistantly arranged along the axial direction of the air guide tube 61, and one ends of the multiple first air guide fins 621 in the same group intersect at the projection point of the air guide hole 610 on the air guide shell 62, and the other ends are respectively connected to the second air guide fins 622 at corresponding positions.

[0034] In some embodiments, the first air guide fin 621 includes multiple fin structures distributed in a "M" shape (more than 8, the greater the number, the better the airflow homogenization effect of the first air guide fin 621). When the airflow derived from the air guide hole 610 hits the intersection of the multiple first air guide fins 621, it will disperse to the surroundings along the guide direction of the multiple first air guide fins 621, and under the guidance of the first air guide fins 621, gradually diffuse to between the multiple second air guide fins 622. Since the second air guide fins 622 are evenly arranged along the length direction in the air guide shell 62, the airflow derived from the air guide hole 610 is evenly diffused to the channel of the air guide shell 62.

[0035] In this way, by providing an air guide shell 62 with air guide fins on the outside of the air guide tube 61, the air flow beams discharged from multiple points on the air guide tube 61 can be evenly diffused along the length direction to the entire channel of the air guide shell 62, so that multiple groups of air flow beams form an air flow curtain evenly distributed in the length direction, avoiding the occurrence of local unevenness. The air flow curtain has better sealing performance and can isolate the air flowing with the fiber bundle, preventing oxygen in the air from entering the carbonization furnace chamber 100, thereby ensuring that the pre-oxidized fiber bundle is carbonized in an oxygen-free environment.

[0036] Furthermore, the height of the first air guide fin 621 is less than or equal to the distance between the air guide pipe 61 and the air guide shell 62, and when the height of the first air guide fin 621 is equal to the distance between the air guide pipe 61 and the air guide shell 62, the air guide pipe 61 and the air guide shell 62 are fixedly connected through the first air guide fin 621. The first air guide fin 621 not only plays an air guiding role, but also strengthens the structure between the air guide pipe 61 and the air guide shell 62 to avoid deformation caused by high-temperature gas passing through the air guide pipe 61 and the air guide shell 62. Correspondingly, both ends of the second air guide fin 622 are also connected to the two side walls of the air guide shell 62 to strengthen the structure of the air guide shell 62.

[0037] The air flow beam flowing out of the air guide duct 61 is evenly distributed in the length direction of the air guide duct 61 after being guided by the first air guide fin 621 and the second air guide fin 622. In order to make the air flow flow stably in the width direction of the air guide groove 600 and improve the sealing performance of the air flow curtain, more than two third air guide fins 623 are provided on the inner side of the air guide shell 62 corresponding to the second air guide fin 622 and the air guide groove 600.

[0038] Furthermore, taking the direction from the second air guide fins 622 to the air guide groove 600 as the first direction, a plurality of third air guide fins 623 are staggeredly distributed on the inner walls of the two plane plates in the first direction, and the third air guide fins 623 have an arc surface facing the side of the air guide pipe 61 .

[0039] Among them, the curvature of the arc-shaped surface gradually increases along the first direction, and the height of the third air guide fin 623 is set to half of the spacing between the flat plates. In this way, when the airflow flows toward the air guide groove 600 in the air guide shell 62, it will be guided by multiple third air guide fins 623 in succession, and the airflow that is disturbed in the thickness direction of the air guide shell 62 will be guided to form a stable airflow curtain. After multiple reversing guides, the airflow discharged from the air guide groove 600 presents a uniform and stable airflow curtain shape, so that the airflow curtain has better sealing properties.

[0040] Since the protective gas perpendicular to the fiber bundle will flow to both sides after contacting the fiber bundle, the flow direction is uncertain. Therefore, it may affect the formation of the airflow curtain and further affect the sealing effect of the airflow curtain. In order to avoid the airflow curtain having an absolute sealing effect in the fiber bundle channel 201 to isolate external oxygen from entering the carbonization furnace chamber 100.

[0041] like Figure 3 and Figure 4 As shown, an air guide plate 63 is provided on the air guide shell 62 corresponding to the air guide groove 600, one end of the air guide plate 63 is fixedly connected to the air guide shell 62, and the other end extends into the fiber bundle channel 201, and the air guide plate 63 is constructed as an arc-shaped strip, and the air guide plate 63 guides the air flow in the air guide shell 62 in the direction of the fiber bundle input, forming an air flow curtain parallel to the fiber bundle, and the horizontal air flow curtain is used to blow in the direction of the fiber bundle entry, so that the air following the fiber bundle flow can be blown out, thereby achieving a sealing effect to prevent oxygen from entering.

[0042] In some embodiments, a plurality of air distribution pipes 60 are provided in the sealed chamber 20 along the conveying direction of the fiber bundle, and at least one air guide shell 62 is provided with an air guide plate 63, that is, the air distribution pipe 60 with the air guide plate 63 can guide the air flow curtain in a direction parallel to the fiber bundle, while the air flow curtain blown out by the remaining air distribution pipes 60 without the air guide plate 63 is perpendicular to the direction of the fiber bundle.

[0043] Generally, an air guide plate 63 is provided on the air distribution pipe 60 located at the inlet side of the sealed chamber 20, so that the air distribution pipe 60 at the inlet side blows out a parallel air flow curtain in the direction of the fiber bundle entering, and the air flow curtain is used to prevent air from entering. The air distribution pipe 60 at the rear side forms multiple air flow curtains perpendicular to the fiber bundle, thereby achieving a further isolation effect.

[0044] In some embodiments, along the conveying direction of the fiber bundle, the distance between the multiple air guide plates 63 and the fiber bundle gradually decreases, that is, the thickness of the air flow curtain formed at the outlet of the air distribution pipe 60 equipped with the air guide plates 63 gradually increases, while the thickness of the air flow curtain on the front side is relatively small, but the air flow speed is relatively large, which can reversely impact the air entering following the fiber bundle. As the fiber bundle enters, the thickness of the air flow curtain formed by the protective gas on the rear side gradually increases, and the sealing effect on the air is better, and the air entry channel is gradually blocked, and finally a better sealing effect is achieved.

[0045] Furthermore, with the angle parallel to the fiber bundle being set to 0°, the air flow guide angle range of the air guide plate 63 to the air guide groove 600 is 0°-±45°, wherein the air flow guide angle of the air guide plate 63 gradually increases, and the air flow curtain guided near the inlet side is parallel to the fiber bundle. As the fiber bundle flows, the air flow curtain guided by the rear air guide plate 63 gradually tilts and finally presents an angle of forty-five degrees, thereby increasing the range of the air blocking by the air curtain and achieving a stronger sealing effect.

[0046] like Figure 1 and Figure 3 As shown, an air supply pipe 21 and an air exhaust pipe 22 are provided on the sealed chamber 20. The air supply pipe 21 is connected to the output end of the air supply fan 40, and the air exhaust pipe 22 is connected to the input end of the exhaust fan 30. The air distribution pipe 60 includes one or more blowing pipe groups 601 and one or more suction pipe groups 602. The blowing pipe group 601 is connected to the air supply pipe 21, and the suction pipe group 602 is connected to the exhaust pipe 22.

[0047] Furthermore, the air guide pipe 61 includes an air blowing pipe 611 and an air suction pipe 612, wherein the air blowing pipe 611 is connected to the air supply pipe 21, and the air suction pipe 612 is connected to the air extraction pipe 22. The air blowing pipe group 601 provided with the air blowing pipe 611 can introduce the protective gas into the fiber bundle channel 201, and the air suction pipe group 602 provided with the air suction pipe 612 can inhale the gas from the fiber bundle channel 201. For example, the air blowing pipe group 601, the air suction pipe group 602 and the three air blowing pipe groups 601 on the rear side are sequentially arranged along the conveying direction of the fiber bundle. The first air blowing pipe group 601 introduces the protective gas in a direction perpendicular to the fiber bundle. The protective air is blown toward the fiber bundle to block the air from entering, and the suction pipe group 602 at the rear side inhales air from the direction in which the fiber bundle enters, and draws the protective air and the mixed air into the suction pipe group 602 to prevent the air from continuing to flow to the rear side with the fiber bundle. The two blowing pipe groups 601 at the rear side are directed toward the direction in which the fiber bundle enters, and are respectively directed at parallel angles and obliquely at 45° to form two isolation air curtains. The last blowing pipe group 601 blows vertically toward the fiber bundle, and has a relatively small outlet, which can form a stronger protective air curtain. The combination of multiple groups of airflow curtains can make the airflow curtain have better sealing properties.

[0048] like Figure 2 As shown, the exhaust duct 311 and the air supply duct 411 both include an air distribution duct 60. When the exhaust duct 311 and the air supply duct 411 both adopt the air distribution duct 60, multiple protective gas flow curtains flowing from bottom to top can also be formed in the carbonization furnace chamber 100. Compared with the supply / exhaust method with a perforated plate or tube, the air flow curtain formed by the air distribution duct 60 is more evenly distributed in the width direction of the entire fiber bundle, and the air flow speed is stable, which can timely bring out the waste gas and impurities generated by the pyrolysis of the pre-oxidized yarn, and avoid the impurities falling back onto the pre-oxidized yarn in the case of uneven airflow.

[0049] It is understandable that the exhaust pipe 311 and the air supply pipe 411 are not uniform in the entire conveying direction of the fiber bundle. In areas where the degree of pyrolysis of the pre-oxidized yarn is higher, the exhaust pipe 311 and the air supply pipe 411 are arranged more densely to accommodate more pyrolysis products and to discharge the pyrolysis products in a timely manner.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0051] The above description of the implementation mode is not restrictive, and the drawings show only one of the implementation modes, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the scope of protection.

Claims

1. A carbon fiber low temperature carbonization furnace, characterized in that: include: A furnace body (10), wherein two groups of heaters (12) are arranged in the furnace body (10), and the two groups of heaters (12) are respectively distributed on the upper and lower sides of the carbonization furnace chamber (100); A sealed chamber (20) is arranged at the entrance and exit of the carbonization furnace chamber (100), and a fiber bundle passage (201) for the fiber bundle to pass through is provided in the sealed chamber (20); an exhaust fan (30), arranged at the top of the furnace body (10), and configured to extract gas from the top of the carbonization furnace chamber (100); an air supply fan (40), arranged at the bottom of the furnace body (10), and configured to provide protective gas from the bottom of the carbonization furnace chamber (100); An air distribution pipe group is provided inside the sealed chamber (20), and the air distribution pipe group includes two groups of air distribution pipes (60) distributed on the upper and lower sides of the fiber bundle channel (201). The air distribution pipe (60) includes an air guide pipe (61) and an air guide shell (62). The opening side of the air guide shell (62) has an air guide groove (600) facing the fiber bundle channel (201). The air guide pipe (61) is provided with an air guide hole (610). After the protective gas in the air guide pipe (61) is discharged from the air guide hole (610), it passes through the guide of the air guide shell (62) and then returns to the fiber bundle channel (201) from the air guide groove (600).

2. The carbon fiber low temperature carbonization furnace according to claim 1, characterized in that: The invention also comprises a traction roller group (50), which is arranged at the front and rear sides of the sealing chamber (20) and is used for traction and transportation of the fiber bundle. The air guide shell (62) is constructed into a "U" shape by a curved plate and two flat plates. The air guide tube (61) and the curved plate are distributed in concentric circles. The air guide hole (610) faces the curved plate. Along the axial direction of the air guide tube (61), a plurality of air guide holes (610) are arranged at equal distances. One or two air guide holes (610) are arranged at the same circumferential position of the air guide tube (61). When the number of the air guide holes (610) is one, the air guide hole (610) points to the center position of the curved plate. When the number of the air guide holes (610) is two, the two air guide holes (610) symmetrically point to the inner side of the curved plate. The angle between the two air guide holes (610) is ninety degrees.

3. The carbon fiber low temperature carbonization furnace according to claim 1, characterized in that: A first air guiding fin (621), a second air guiding fin (622) and a third air guiding fin (623) are sequentially arranged on the inner side wall of the air guiding shell (62) in a direction from the air guiding tube (61) to the air guiding groove (600); the first air guiding fins (621) are arranged in a plurality of groups corresponding to the number and position of the air guiding holes (610); each group of the first air guiding fins (621) is arranged in a plurality of radially distributed groups with the air guiding hole (610) as the center; a plurality of the second air guiding fins (622) are arranged in a plurality of equal distances along the axial direction of the air guiding tube (61); one ends of the plurality of the first air guiding fins (621) in the same group intersect at a projection point of the air guiding hole (610) on the air guiding shell (62); and the other ends are respectively connected to the second air guiding fins (622) at corresponding positions.

4. The carbon fiber low temperature carbonization furnace according to claim 3, characterized in that: The height of the first air guide fin (621) is less than or equal to the distance between the air guide pipe (61) and the air guide shell (62).

5. The carbon fiber low temperature carbonization furnace according to claim 3, characterized in that: More than two third air guide fins (623) are provided on the inner side of the air guide shell (62) corresponding to between the second air guide fin (622) and the air guide groove (600), with the direction from the second air guide fin (622) to the air guide groove (600) being a first direction, and a plurality of the third air guide fins (623) being staggeredly distributed on the inner walls of the two flat plates in the first direction, and the third air guide fins (623) having an arc-shaped surface on a side facing the air guide pipe (61).

6. The carbon fiber low temperature carbonization furnace according to claim 5, characterized in that: The curvature of the arc-shaped surface increases gradually along the first direction, and the height of the third air guide fins (623) is set to half the spacing between the plane plates.

7. The carbon fiber low temperature carbonization furnace according to claim 5, characterized in that: An air guide plate (63) is provided on the air guide shell (62) at a position corresponding to the air guide groove (600), one end of the air guide plate (63) is fixedly connected to the air guide shell (62), and the other end extends into the fiber bundle channel (201), the air guide plate (63) is constructed as an arc-shaped strip, and the air guide plate (63) guides the air flow in the air guide shell (62) towards the direction of the fiber bundle input; A plurality of air distribution pipes (60) are provided in the sealed chamber (20) along the conveying direction of the fiber bundle, and at least one of the air guide shells (62) is provided with the air guide plate (63). Along the conveying direction of the fiber bundle, the spacing between the plurality of air guide plates (63) and the fiber bundle gradually decreases, and the angle parallel to the fiber bundle is set to 0°. The air flow guide angle of the air guide plate (63) directed to the air guide groove (600) is in the range of 0°-±45°.

8. The carbon fiber low temperature carbonization furnace according to claim 7, characterized in that: The sealed chamber (20) is provided with an air supply pipe (21) and an air exhaust pipe (22); the air supply pipe (21) is in communication with the output end of the air supply fan (40); the air exhaust pipe (22) is in communication with the input end of the air exhaust fan (30); the air distribution pipe (60) comprises one or more blowing pipe groups (601) and one or more suction pipe groups (602); the blowing pipe group (601) is in communication with the air supply pipe (21); and the suction pipe group (602) is in communication with the air exhaust pipe (22).

9. The carbon fiber low temperature carbonization furnace according to claim 5, characterized in that: An exhaust duct (31) is provided on the upper side of the furnace body (10) corresponding to the carbonization furnace chamber (100), and the exhaust duct (31) is connected to the input end of the exhaust fan (30). An air supply duct (41) is provided on the lower side of the furnace body (10) corresponding to the carbonization furnace chamber (100), and the air supply duct (41) is connected to the output end of the air supply fan (40). The exhaust duct (31) is provided with a plurality of exhaust ducts (311), and the air supply duct (41) is provided with a plurality of supply ducts (411), and the exhaust ducts (311) and the supply ducts (411) are symmetrically distributed up and down.

10. The carbon fiber low temperature carbonization furnace according to claim 9, characterized in that: The air exhaust pipe (311) and the air supply pipe (411) both include an air distribution pipe (60).

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