Carbon fiber pre-oxidation furnace and working method thereof

Abstract

The invention belongs to the technical field of carbon fiber production equipment, and particularly relates to a carbon fiber pre-oxidation furnace and a working method thereof.The pre-oxidation furnace comprises a furnace body, and a plurality of temperature zones are arranged in the length extension direction of the furnace body; the conveying mechanism is arranged at the bottom of the furnace body and is configured to convey the carbon fibers into all the temperature zones in the length direction of the furnace body; wherein a heat insulation device is arranged between every two adjacent temperature areas, and each temperature area is internally provided with an independent heating module and an airflow guide device. According to the carbon fiber pre-oxidation furnace and the working method thereof, the independent heating modules and the heat insulation devices between the adjacent temperature zones are arranged in the temperature zones, heat mixing of the temperature zones is prevented, and the temperature of the single zone is kept stable; and the airflow guide device is matched to ensure uniform distribution of hot air, so that local cracks or fractures of carbon fibers caused by uneven temperature are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon fiber production equipment, and particularly relates to a carbon fiber pre-oxidation furnace and its working method. Background Art

[0002] The carbon fiber pre-oxidation furnace is a key equipment in the carbon fiber production process. Its main function is to transform the linear macromolecular chains of polyacrylonitrile (PAN) raw filaments into heat-resistant ladder structures, so as to ensure that the fibers maintain a stable shape during the subsequent high-temperature carbonization process and do not melt or burn. The temperature control of the carbon fiber pre-oxidation furnace is very important. If the temperature control is uneven, it is easy to cause cracks or fractures in the carbon fiber in local areas.

[0003] Therefore, how to avoid cracks or fractures in the carbon fiber in the local area of the carbon fiber pre-oxidation furnace is a technical problem that those skilled in the art need to solve urgently.

[0004] It should be noted that the above information disclosed in this background art section is only used to understand the background art of the concept of this application. Therefore, the above description is not considered as information of the prior art. Summary of the Invention

[0005] The embodiments of the present disclosure provide at least a carbon fiber pre-oxidation furnace and its working method.

[0006] In a first aspect, the embodiments of the present disclosure provide a carbon fiber pre-oxidation furnace, including: A furnace body, along the length extension direction of the furnace body, there are several temperature zones arranged; A conveying mechanism, arranged at the bottom of the furnace body and configured to convey the carbon fiber to each temperature zone along the length direction of the furnace body; Wherein, an insulation device is arranged between adjacent temperature zones, and an independent heating module and an air flow guiding device are arranged in each temperature zone.

[0007] In an optional implementation manner, the insulation device includes: Several high-pressure nitrogen nozzles, which are installed on the side wall of the furnace body below the uniform flow orifice plate and the spraying direction is perpendicular to the side wall; An infrared pair emission sensor, which is adapted to capture the position signal of the front end of the carbon fiber and is arranged at the inlet of each temperature zone; Wherein, the high-pressure nitrogen nozzles and the infrared pair emission sensor are both electrically connected to a control module, and the control module is adapted to receive the position signal of the infrared pair emission sensor and is configured to start the high-pressure nitrogen nozzles when the carbon fiber enters a new temperature zone.

[0008] In an optional implementation manner, the air flow guiding device includes: A blower, which is arranged on the top of the furnace body; The flow equalizing orifice plate is arranged between the heating module and the fan, and baffles are arranged between the flow equalizing orifice plates of adjacent temperature zones. A plurality of guide vanes are arranged at the bottom of the furnace body.

[0009] In an optional embodiment, return air channels are arranged on both side walls of the furnace body. The inlets of the return air channels are located at the ends of the guide vanes and the number thereof corresponds to that of the guide vanes. Moreover, the outlets of the return air channels are arranged on the side walls above the furnace body and close to the air inlet of the fan.

[0010] In an optional embodiment, the heating module includes: A heating plate which is arranged directly above the conveying mechanism and in which heating wires are arranged. The heating wires are evenly distributed in the heating plate; A switching tube and a temperature sensor. The switching tube is arranged in the power supply circuit of the heating wires, and both the switching tube and the temperature sensor are electrically connected to a control module.

[0011] In an optional embodiment, the temperature sensor is adapted to detect the temperature of the carbon fiber surface. The control module is adapted to receive the temperature data of the temperature sensor and is configured to generate a PWM signal for temperature regulation and input it to the control end of the switching tube to control the temperature of the heating wires.

[0012] In an optional embodiment, the conveying mechanism includes: A main roller connected to a servo motor; At least one secondary roller arranged parallel to the main roller along the length direction of the furnace body to form a carbon fiber conveying path.

[0013] In an optional embodiment, the conveying mechanism includes: A main roller connected to a servo motor; At least one secondary roller distributed in a staggered layout on the upper and lower sides of the main roller along the length direction of the furnace body to form a carbon fiber conveying path.

[0014] In an optional embodiment, the distance between adjacent secondary rollers is 150 - 300 mm.

[0015] In a second aspect, the embodiments of the present disclosure further provide a working method of a carbon fiber pre-oxidation furnace, including: Step S1, starting the independent heating modules of each temperature zone to heat the carbon fiber and setting the temperature difference between adjacent temperature zones to be 50 - 150 °C according to a preset gradient; Step S2, activating the servo motor of the conveying mechanism to drive the main roller to traction the carbon fiber through each temperature zone in turn at a constant linear speed, and controlling the residence time of a single stroke to be 20 - 40 minutes; Step S3: Start the top fans of each temperature zone, allowing the hot air to flow vertically downward through the flow equalizing orifice plate to the surface of the carbon fiber. The bottom guide vanes direct the air flow to the inlet of the return air channel, forming a closed-loop circulation from the furnace top to the side wall and then back to the fan. Step S4: Real-time monitor the surface temperature of the carbon fiber through the temperature sensor. When the deviation between the detected temperature and the target temperature exceeds ±5°C, the control module dynamically adjusts the PWM duty cycle and the power of the heating wire to maintain the surface temperature of the carbon fiber within the set range in each temperature zone. Step S5: When the front end of the carbon fiber enters a new temperature zone (110), the control module activates the heat insulation device (300).

[0016] The beneficial effects of the present invention are as follows. The carbon fiber pre-oxidation furnace and its working method set several temperature zones in the oxidation furnace body. The conveying mechanism sequentially conveys the carbon fiber into the corresponding temperature zones. Independent heating modules are set in each temperature zone, and heat insulation devices are provided between adjacent temperature zones to prevent heat transfer between different temperature zones and maintain the temperature stability in a single temperature zone. Air flow guiding devices are also set in each temperature zone to ensure uniform distribution of hot air in the temperature zone. Through the coordinated action of the independent heating modules, air flow guiding devices and heat insulation devices in each temperature zone, it is avoided that the uneven temperature distribution in each temperature zone of the carbon fiber pre-oxidation furnace causes cracks or fractures in the carbon fiber in local areas.

[0017] Other features and advantages of the present invention will be described in the following description of the specification, and in part, will be obvious from the description of the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0018] To make the above objectives, features, and advantages of the present invention more obvious and understandable, specific preferred embodiments are hereby given, and in conjunction with the accompanying drawings, the detailed description is as follows. Description of the Drawings

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 A three-dimensional view of a carbon fiber pre-oxidation furnace provided by an embodiment of the present disclosure; Figure 2 A three-dimensional view of the conveying mechanism of a carbon fiber pre-oxidation furnace provided by Embodiment 1 of the present disclosure; Figure 3Stereogram of Embodiment 2 of a carbon fiber pre-oxidation furnace conveying mechanism provided by an embodiment of the present disclosure; Figure 4 Principle block diagram of a control module of a carbon fiber pre-oxidation furnace provided by an embodiment of the present disclosure.

[0021] In the figure: 100, furnace body; 110, temperature zone; 200, conveying mechanism; 210, main roller; 220, driven roller; 300, heat insulation device; 310, high-pressure nitrogen nozzle; 400, heating module; 410, heating plate; 500, air flow guiding device; 510, fan; 520, flow equalizing orifice plate; 521, baffle; 530, guide vane; 600, return air duct; 610, inlet; 620, outlet. Specific embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0023] In this document, when it is mentioned that a first component is located on a second component, this may mean that the first component can be directly formed on the second component, or a third component can be inserted between the first component and the second component. In addition, in the drawings, for the effective description of the technical content, the thickness of the components can be exaggerated or reduced.

[0024] In this document, when an element or layer is referred to as "being located on", "joined to", "connected to", "attached to", or "coupled to" another element or layer, it can be directly located on, joined, connected, attached, or coupled to the other element or layer, or there may be intermediate elements or layers. In contrast, when an element is referred to as "directly on another element or layer", "directly joined to", "directly connected to", "directly attached to", or "directly coupled to" another element or layer, there may be no intermediate elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (for example, "between" vs. "directly between", "adjacent" vs. "directly adjacent", etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] In this document, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0026] The terms used herein are only for describing specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an", and "the" may also be intended to include the plural forms, unless clearly indicated otherwise in the context. The terms "comprising", "including", and "having" are inclusive, and thus specify the presence of the specified features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an order of execution. Additional or alternative steps may be employed.

[0027] As used herein, phrases such as "in one embodiment", "according to one embodiment", "in some embodiments", etc. generally refer to the fact that the specific feature, structure, or characteristic after the phrase may be included in at least one embodiment of the present disclosure. Thus, a specific feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example", "exemplary", etc. are used "as an example, instance, or illustration. Any embodiment, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other embodiments, aspects, or designs. Instead, the use of the terms "example", "exemplary", etc. is intended to present concepts in a specific manner.

[0028] It has been found through research that the disadvantages of the prior art are as follows: The carbon fiber pre-oxidation furnace oxidizes carbon fibers through multiple temperature zones. In the traditional carbon fiber pre-oxidation furnace, the temperature control of each temperature zone is prone to unevenness, resulting in cracks or fractures in the carbon fibers in local areas.

[0029] Based on the above research, the embodiments of the present disclosure provide a carbon fiber pre-oxidation furnace and its working method. Through the synergistic action of the independent heating modules, air flow guiding devices, and heat insulation devices in each temperature zone, it is avoided that the uneven temperature distribution in each temperature zone of the carbon fiber pre-oxidation furnace causes cracks or fractures in the carbon fibers in local areas.

[0030] Regarding the defects existing in the above solutions, they are all the results obtained by the inventors through practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed in this disclosure by the present disclosure for the above problems should all be the contributions made by the inventors during the process of this disclosure.

[0031] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0032] The following will describe in detail some embodiments of the present invention with reference to the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0033] See Figure 1 , an embodiment of the present disclosure provides a carbon fiber pre-oxidation furnace, including: a furnace body 100, along the length extension direction of the furnace body 100, a plurality of temperature zones 110 are provided, and adjacent temperature zones 110 are physically isolated through a heat insulation device 300 to prevent temperature crossover between adjacent temperature zones 110.

[0034] Furthermore, a conveying mechanism 200 is provided at the bottom of the furnace body 100, which is configured to convey carbon fiber along the length direction of the furnace body 100 into each temperature zone 110 for heating.

[0035] Continue to see Figure 1 , in each temperature zone 110, an independent heating module 400 and an air flow guiding device 500 are provided. The independent heating module 400 enables each temperature zone 110 to form a gradient temperature rise to meet the temperature requirements of different reaction stages during the carbon fiber pre-oxidation process; the air flow guiding device 500 eliminates the heating blind spots in the temperature zone 110 through uniform air supply. The combination of the two ensures that the temperature distribution inside each temperature zone 110 is uniform and the gradient temperature rise curve is stable.

[0036] Continue to see Figure 1 , in some embodiments, the air flow guiding device 500 includes: a fan 510, which is provided at the top of the furnace body 100; a flow equalizing orifice plate 520 is provided between the fan 510 and the heating module 400. The hot air in each temperature zone 110 is blown by the fan 510 towards the flow equalizing orifice plate 520, as Figure 1 shown by the F1 arrow in, the hot air is converted into laminar flow through the flow equalizing orifice plate 520 and evenly distributed on the surface of the carbon fiber to ensure uniform heating of the carbon fiber. Preferably, a baffle 521 is provided between the flow equalizing orifice plates 520 of adjacent temperature zones 110 to prevent the hot air of adjacent temperature zones 110 from crossing each other, thereby ensuring uniform distribution of the hot air.

[0037] See Figure 2, in some embodiments, a plurality of flow guiding vanes 530 are provided at the bottom of the furnace body 100, and the ends of the flow guiding vanes 530 are connected to the inlet 610 of the return air passage 600. As shown by the F2 arrow in Figure 1 , the hot air blown down by the blower 510 is guided by the flow guiding vanes 530 into the return air passage 600 and rises to be blown out from the outlet 620 of the return air passage 600. The outlet 620 of the return air passage 600 is provided on the side wall above the furnace body 100 and close to the air inlet of the blower 510 to promote waste gas recirculation, reduce the demand for fresh air, and thus save heating energy.

[0038] Continue to refer to Figure 1 , in some embodiments, the heat insulation device 300 includes: a plurality of high-pressure nitrogen nozzles 310, which are installed on the side wall of the furnace body 100 below the flow equalizing orifice plate 520 and the spraying direction is perpendicular to the side wall. The perpendicular spraying direction is orthogonal to the laminar flow direction of the flow equalizing orifice plate 520 to avoid the turbulent disturbance caused by the superposition of airflows and maintain the wind speed stability in the furnace body 100.

[0039] Refer to Figure 4 , in some embodiments, an infrared pair emission sensor is further provided at the inlet of each temperature zone 110, which is suitable for capturing the position signal of the front end of the carbon fiber; and, both the high-pressure nitrogen nozzle 310 and the infrared pair emission sensor are electrically connected to the control module. The control module is suitable for receiving the position signal of the infrared pair emission sensor and is configured to start the high-pressure nitrogen nozzle 310 when the carbon fiber enters the new temperature zone 110. Through the above settings, when the carbon fiber enters the new temperature zone 110, starting the nitrogen nozzle in time can prevent the heat of the previous temperature zone 110 from affecting the new temperature zone 110, which is beneficial to maintaining the temperature gradient between adjacent temperature zones 110. At the same time, spraying on demand instead of continuously can save nitrogen and reduce costs.

[0040] Refer to Figure 2 , in some embodiments, the heating module 400 includes: a heating plate 410, which is arranged directly above the conveying mechanism 200 and an electric heating wire is arranged in the heating plate 410. A power supply interface is preset at one end of the heating plate 410, and both ends of the electric heating wire are connected to the two power supply interfaces; and, the electric heating wires are evenly distributed in the heating plate 410 to form a uniform heat radiation field and eliminate the uneven heating caused by the coiling of traditional resistance wires.

[0041] Refer to Figure 4 , a switching tube is arranged in the power supply circuit of the electric heating wire. Both the switching tube and the temperature sensor are electrically connected to a control module. The temperature sensor is suitable for detecting the temperature of the carbon fiber surface. The control module is suitable for receiving the temperature data of the temperature sensor and is configured to generate a PWM signal for temperature regulation and input it to the control end of the switching tube to control the temperature of the electric heating wire. By adjusting the PWM signal through the switching tube, it can quickly respond to the temperature change of the carbon fiber surface and reduce its temperature fluctuation.

[0042] Continue to refer to Figure 2 In some embodiments, the conveying mechanism 200 includes: a main roller 210 driven by a servo motor; a plurality of secondary rollers 220 arranged in parallel at the bottom of the furnace body 100, forming a wavy conveying path for carbon fiber with the main roller 210, so that the carbon fiber presents a "snake-shaped" movement during conveying, effectively increasing its heating area.

[0043] Refer to Figure 3 In some embodiments, the conveying mechanism 200 includes: a main roller 210 driven by a servo motor; a plurality of secondary rollers 220 distributed on the upper and lower sides of the main roller 210 in a staggered layout along the length direction of the furnace body 100, forming a horizontal conveying path for carbon fiber, and realizing the sequential conveying of carbon fiber into the corresponding temperature zones 110 for heating.

[0044] Refer to Figure 2 and Figure 3 In some embodiments, the distance between adjacent secondary rollers 220 in the conveying mechanism 200 is 150 - 300 mm, preferably 150 mm, 300 mm or 200 mm. If the distance is too small, the bending radius of the carbon fiber is too small, increasing stress and prone to wire breakage; if the distance is too large, it will affect the stability of the fiber and the heating uniformity.

[0045] As a specific implementation manner, the temperature sensor can adopt a K-type thermocouple (OMEGA KMQXL-062G-12) embedded below the conveying path to detect the surface temperature of the carbon fiber in real time, the infrared opposed sensor adopts Omron (E3Z-D61), and the control module adopts Siemens S7-1200.

[0046] The temperature adjustment method and the method of controlling the heat insulation device through the control module involved in this embodiment both belong to the prior art, and this embodiment does not make a substantial improvement to the above methods.

[0047] In some embodiments, a working method of a carbon fiber pre-oxidation furnace is further provided, including: Step S1, start the independent heating modules of each temperature zone to heat the carbon fiber and set the temperature difference between adjacent temperature zones to 50 - 150 °C according to a preset gradient; Step S2, activate the servo motor of the conveying mechanism to drive the main roller, and traction the carbon fiber through each temperature zone at a constant linear speed, and the residence time for a single stroke is controlled within 20 - 40 minutes; Step S3, start the fans at the top of each temperature zone, so that the hot air flows vertically downward through the flow equalizing orifice plate to the surface of the carbon fiber, and the bottom guide vanes direct the air flow to the inlet of the return air channel, forming a closed-loop cycle from the furnace top to the side wall and then back to the fan; Step S4: The surface temperature of the carbon fiber is monitored in real time by a temperature sensor. When the deviation between the detected temperature and the target temperature exceeds ±5°C, the control module dynamically adjusts the PWM duty cycle to adjust the power of the heating wire, so that the surface temperature of the carbon fiber in each temperature zone is maintained within the set range. Step S5: When the front end of the carbon fiber enters a new temperature zone, the control module activates the heat insulation device.

[0048] As Example 1, at least one embodiment also discloses a working method of a carbon fiber pre-oxidation furnace, and the specific steps are as follows: Step S1: Start the heating module 400, and set the temperature gradient of six temperature zones as 200°C → 250°C → 300°C → 350°C → 400°C → 450°C, with an adjacent temperature difference of 50°C. Step S2: The servo motor drives the main roller 210 at a linear speed of 1.2 m / min, and the one-way residence time of the carbon fiber is 30 minutes. Step S3: Start the blower 510. The hot air forms a laminar flow through the flow equalizing orifice plate 520 and blows vertically onto the surface of the carbon fiber. The bottom deflector 530 divides the air flow into six paths and introduces it into the return air channel 600 to form a cycle. Step S4: The temperature sensor monitors in real time. When the detected temperature deviates from the set value by ±5°C, the control module adjusts the PWM duty cycle, and the power response time < 3 seconds. Step S5: When the carbon fiber enters a new temperature zone, the infrared sensor triggers the injection of high-pressure nitrogen for 30 seconds.

[0049] After testing, the wire breakage rate of the carbon fiber produced by the pre-oxidation furnace in Example 1 is 0.35%.

[0050] Comparative Example 1, the difference from Example 1 is that the air flow guiding device and the heat insulation device are not used, and the specific steps are as follows: Step S1: Start the heating module 400, and set the temperature gradient of six temperature zones as 200°C → 250°C → 300°C → 350°C → 400°C → 450°C, with an adjacent temperature difference of 50°C. Step S2: The servo motor drives the main roller 210 at a linear speed of 1.2 m / min, and the one-way residence time of the carbon fiber is 30 minutes. Step S3: The temperature sensor monitors in real time. When the detected temperature deviates from the set value by ±5°C, the control module adjusts the PWM duty cycle, and the power response time < 3 seconds.

[0051] After testing, the wire breakage rate of the carbon fiber produced by the pre-oxidation furnace in Comparative Example 1 is 1.2%.

[0052] The experimental results of Example 1 and Comparative Example 1 show that the wire breakage rate of the carbon fiber produced by this pre-oxidation furnace is reduced from 1.2% of the traditional equipment to 0.35%, which verifies the superiority of the temperature control system of this carbon fiber pre-oxidation furnace.

[0053] In summary, in this carbon fiber pre-oxidation furnace and its working method, several temperature zones 110 are set in the oxidation furnace body 100. The conveying mechanism 200 conveys the carbon fiber to the corresponding temperature zones 110 in sequence. An independent heating module 400 is set in each temperature zone 110, and a heat insulation device 300 is set between adjacent temperature zones 110 to prevent heat transfer between different temperature zones 110 and keep the temperature stable in a single temperature zone 110. An air flow guiding device 500 is also set in each temperature zone 110 to ensure uniform distribution of hot air in the temperature zone 110. Through the coordinated action of the independent heating module 400, the air flow guiding device 500 and the heat insulation device 300 in each temperature zone 110, it is avoided that the uneven temperature distribution in each temperature zone 110 of the carbon fiber pre-oxidation furnace causes cracks or fractures in the carbon fiber in local areas.

[0054] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0055] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, terms such as "first", "second" and other numerical terms used herein do not imply an order or sequence unless clearly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer or section discussed above can be referred to as the second element, component, region, layer or section.

[0056] Spatial relative terms, such as "inner", "outer", "below", "beneath", "under", "above", "upper", etc., may be used herein to facilitate the description of the relationship of one element or feature to another element or feature as illustrated in the figures. Except for the orientation depicted in the figures, spatial relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as "below" or "beneath" other elements or features will be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein are to be interpreted accordingly.

[0057] In the above discussion, unless otherwise specified, when used to describe a numerical value, the terms "about", "approximately", "substantially", etc. mean a variation of + / − 10% of that value.

[0058] Inspired by the above-described ideal embodiments of the present invention, through the above description, relevant staff can make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A carbon fiber preoxidation furnace, characterized in that: include: A furnace body (100), with a plurality of temperature zones (110) arranged along a length extension direction of the furnace body (100); A conveying mechanism (200) is disposed at the bottom of the furnace body (100) and is configured to convey the carbon fibers to each temperature zone (110) along the length direction of the furnace body (100); A heat insulation device (300) is provided between adjacent temperature zones (110), and an independent heating module (400) and an airflow guide device (500) are provided in each temperature zone (110); The heat insulation device (300), the independent heating module (400) and the airflow guide device (500) are integrated into a control system to dynamically control the temperature field.

2. The pre-oxidation furnace according to claim 1, characterized in that: The heat insulation device (300) comprises: A plurality of high-pressure nitrogen nozzles (310) are installed on the side wall of the furnace body (100) below the flow balancing orifice plate (520) and the spraying direction is perpendicular to the side wall; An infrared counter-radiation sensor, which is suitable for capturing the position signal of the front end of the carbon fiber and is arranged at the entrance of each temperature zone (110); The high-pressure nitrogen nozzle (310) and the infrared radiation sensor are both electrically connected to a control module, and the control module is suitable for receiving a position signal of the infrared radiation sensor and is configured to start the high-pressure nitrogen nozzle (310) when the carbon fiber enters the new temperature zone (110).

3. The pre-oxidation furnace according to claim 1, characterized in that: The airflow guiding device (500) comprises: A fan (510) is arranged on the top of the furnace body (100); A flow balancing orifice plate (520) is arranged between the heating module (400) and the fan (510), and a baffle plate (521) is arranged between the flow balancing orifice plates (520) of adjacent temperature zones (110); A plurality of guide plates (530) are arranged at the bottom of the furnace body (100).

4. The pre-oxidation furnace according to claim 3, characterized in that: Both side walls of the furnace body (100) are provided with return air channels (600); the inlets (610) of the return air channels (600) are located at the ends of the guide vanes (530) and the number of the return air channels corresponds to the number of the guide vanes (530); and the outlets (620) of the return air channels (600) are provided on the side walls above the furnace body (100) and close to the air inlet of the fan (510).

5. The pre-oxidation furnace according to claim 4, characterized in that: The heating module (400) comprises: A heating plate (410) is arranged directly above the conveying mechanism (200) and electric heating wires are arranged inside the heating plate (410), and the electric heating wires are evenly distributed inside the heating plate (410); The switch tube and the temperature sensor are arranged in the heating wire power supply circuit and are both electrically connected to a control module.

6. The pre-oxidation furnace according to claim 5, characterized in that: The temperature sensor is suitable for detecting the temperature of the carbon fiber surface, and the control module is suitable for receiving temperature data from the temperature sensor and is configured to generate a PWM signal for temperature regulation and input it to the control end of the switch tube to control the temperature of the heating wire.

7. The pre-oxidation furnace according to claim 1, characterized in that: The conveying mechanism (200) comprises: A main roller (210) connected to a servo motor; At least one slave roller (220) is arranged in parallel with the main roller (210) along the length direction of the furnace body to form a carbon fiber conveying path.

8. The pre-oxidation furnace according to claim 1, characterized in that: The conveying mechanism (200) comprises: A main roller (210) connected to a servo motor; At least one slave roller (220) is distributed on the upper and lower sides of the main roller (210) in a staggered layout along the length direction of the furnace body, forming a carbon fiber conveying path.

9. The pre-oxidation furnace according to claims 7-8, characterized in that: The spacing between adjacent secondary rollers (220) is 150-300 mm.

10. A working method of a carbon fiber preoxidation furnace, characterized in that: include: Step S1, starting the independent heating module (400) of each temperature zone (110) to heat the carbon fiber and setting the temperature difference between adjacent temperature zones (110) to 50-150° C. according to a preset gradient; Step S2, activating the servo motor of the conveying mechanism (200) to drive the main roller (210), pulling the carbon fiber through each temperature zone (110) in sequence at a constant linear speed, and controlling the residence time of a single stroke to be 20-40 minutes; Step S3, starting the top fan (510) of each temperature zone (110) to allow the hot air to pass through the flow balancing plate (520) and blow vertically downward to the surface of the carbon fiber, and the bottom guide plate (530) guides the air flow to the inlet (610) of the return air channel (600), forming a closed loop circulation from the furnace top to the side wall and then back to the fan (510); Step S4, monitoring the carbon fiber surface temperature in real time through a temperature sensor, when the detected temperature deviates from the target temperature by more than ±5°C, the control module dynamically adjusts the PWM duty cycle and adjusts the heating wire power so that the surface temperature of the carbon fiber in each temperature zone (110) is maintained within a set range; Step S5: when the front end of the carbon fiber enters the new temperature zone (110), the control module starts the heat insulation device (300).

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