Dual-power heating system for graphitization of carbon fiber

Abstract

A dual-power heating system for graphitization of a carbon fiber, comprising: a conveying wheel (1), two electrode apparatuses (2), a power supply unit (4), and an auxiliary heating device (5). The two electrode apparatuses (2) are respectively a first electrode apparatus (201) and a second electrode apparatus (202), the first electrode apparatus (201) and the second electrode apparatus (202) are sequentially arranged in a conveying direction of the carbon fiber (9) and in contact with the carbon fiber (9), and the first electrode apparatus (201) and the second electrode apparatus (202) are spaced apart to form a heating region (3) between the first electrode apparatus (201) and the second electrode apparatus (202); the positive and negative ends of the power supply unit (4) are electrically connected to the first electrode apparatus (201) and the second electrode apparatus (202) respectively and can apply a current to the carbon fiber (9) by means of the first electrode apparatus (201) and the second electrode apparatus (202); the auxiliary heating device (5) is arranged in the heating region (3) and can heat the carbon fiber (9) in a non-contact mode. Two heating modes are used to heat the carbon fiber (9), to jointly implement an ultra-high temperature environment for graphitization of the carbon fiber (9) with a low energy consumption, so that the service life of a heating device is greatly prolonged and the "skin core" problem of a graphitized carbon fiber is alleviated.

Description

Carbon fiber graphitization dual power heating system Technical Field

[0001] The present application belongs to the field of high-grade carbon fiber production technology in the fields of national defense science and technology, aerospace, industry and civil affairs, and in particular relates to a carbon fiber graphitization dual-power heating system. Background Art

[0002] Graphite fiber is a core scientific material involved in important fields such as national defense, aviation, and aerospace. Carbon fiber graphitization involves heat-treating ordinary carbon fibers at temperatures of approximately 2000-3000 degrees Celsius. Currently, my country lacks mature, high-quality graphite fiber production technology, particularly ultra-high-temperature heating for carbon fiber graphitization, a core technology. This technology has long been subject to international restrictions, including import restrictions on graphite fiber products. Because advanced foreign technologies have not been published in the literature and there are no publicly available patents, we are unable to grasp the specific solutions for the most advanced international carbon fiber graphitization technology. However, driven by national defense needs, we have achieved a significant breakthrough after years of arduous technical research.

[0003] In the field of experimental production and scientific research, the ultra-high temperature production environment for carbon fiber graphitization is mainly achieved through graphite furnace, radio frequency coupled heating, microwave heating, plasma heating, laser heating, etc.

[0004] Among them, graphite furnace heating technology belongs to passive heating of carbon fiber. The temperature of the furnace chamber is used to bake the carbon fiber to obtain a high temperature. This requires that the temperature of the furnace chamber of the graphite furnace be higher than that of the carbon fiber. Although graphite is a high-temperature resistant material, graphite sublimates very obviously at such temperatures, so the life of the graphite furnace is very short, only a few dozen hours, and it is difficult to reach a higher temperature. Carbon fiber made of graphite is almost thermally insulated at high temperatures. The baking heating method of the graphite furnace will result in a low temperature in the inner layer of the fiber, poor graphitization effect, and a prominent "skin-core" phenomenon. At this stage, my country's graphite furnace heating technology has major problems with the mass production, quality stability, and production cost of carbon fiber.

[0005] The current RF coupling heating technology mainly uses two coaxial couplers to load high-power electromagnetic oscillations onto carbon fibers, causing them to generate axial oscillating currents, thereby achieving contactless heating of the carbon fibers. This heating method has relatively low energy consumption, a long lifespan for the heating equipment, and very short heating and cooling times. One characteristic of RF heating technology is that due to the skin effect of the mobile charges of the oscillating current, the heat generation location of the carbon fibers is mainly distributed on the surface of the fiber bundles, and RF coupling heating requires fiber bundle twisting operations. RF heating also has a relatively obvious "skin-core" phenomenon. The existing RF heating technology is relatively difficult to design, install, debug, and operate. There is a problem of strong electromagnetic wave radiation during equipment operation. It is necessary to redesign the RF heating technology solution, striving to make the RF heating solution simple in structure, easy to install and debug, reliable in operation, and avoid strong electromagnetic radiation.

[0006] None of the above existing heating technologies in my country can provide an ideal ultra-high temperature production environment for graphitization, which has resulted in high-quality graphite fiber, as an advanced material in the fields of national defense, aerospace, etc., being subject to clear international restrictions.

[0007] Summary of the Invention

[0008] In response to at least one shortcoming in the related art, the present application provides a dual-power heating system for carbon fiber graphitization, which uses two heating methods to heat the carbon fiber, thereby providing a good high-temperature environment for the carbon fiber.

[0009] The present application provides a carbon fiber graphitization dual-power heating system, comprising:

[0010] Two or more conveying wheels, which are arranged along the production direction of the carbon fibers to position and convey the carbon fibers;

[0011] two electrode devices, namely a first electrode device and a second electrode device, the first electrode device and the second electrode device being sequentially arranged in a conveying direction of the carbon fibers and in contact with the carbon fibers, the first electrode device and the second electrode device being spaced apart to form a heating zone between the first electrode device and the second electrode device;

[0012] a power supply unit, whose positive and negative ends are electrically connected to the first electrode device and the second electrode device respectively and can apply current to the carbon fiber via the first electrode device and the second electrode device;

[0013] An auxiliary heating device is provided in the heating zone and can heat the carbon fibers in a contactless manner.

[0014] In some embodiments of the present application, the auxiliary heating device is a graphite furnace, a radio frequency coupling device, a microwave heating cavity, a plasma heating cavity or a laser tunnel.

[0015] In some embodiments of the present application, the auxiliary heating device is a radio frequency coupling device, and the radio frequency coupling device includes:

[0016] a radio frequency generator for providing electromagnetic oscillations;

[0017] A coaxially arranged shell and core wire, the core wire is located inside the shell and is hollow in the axial direction, the shell and the core wire are connected to the radio frequency generator to generate electromagnetic oscillations on the shell and the core wire, the shell and the core wire are arranged in the heating zone and the carbon fiber passes through the inside of the core wire, the carbon fiber segment located inside the core wire serves as a conductor wire and together with the shell and the core wire constitutes a coaxial coupler, the electromagnetic oscillation induces an anti-phase oscillating current on the carbon fiber segment located inside the core wire to heat the carbon fiber segment.

[0018] In some embodiments of the present application, the wavelength of the electromagnetic oscillation standing wave in the electromagnetic oscillation is λ, the axial length of the coaxial coupler is set to λ / 2, and the coaxial coupler is located between two adjacent current standing wave nodes of the electromagnetic oscillation standing wave.

[0019] In some embodiments of the present application, each of the electrode devices comprises:

[0020] a false twisting machine, wherein the axis thereof is coaxial with the carbon fibers, the false twisting machine being configured to allow the carbon fibers to pass along the axis and to rotate relative to the axis to twist the carbon fibers;

[0021] A conductive component connects the power supply unit and the false twisting machine and can conduct current from the power supply unit to the false twisting machine.

[0022] In some embodiments of the present application, the false twisting machine comprises:

[0023] A frame having a chamber therein, the frame including an input port and an output port sequentially arranged at both ends of the frame along the conveying direction of the carbon fiber, the carbon fiber entering the chamber through the input port and being output from the chamber through the output port;

[0024] a plurality of rotating wheels disposed in the chamber and connected to the frame, the plurality of rotating wheels being respectively disposed on both sides of the axis, two rotating wheels located at both ends of the plurality of rotating wheels being tangent to the axis, the carbon fibers being sequentially wound around the plurality of rotating wheels and being capable of driving the plurality of rotating wheels to rotate, the plurality of rotating wheels being conductive;

[0025] A driving member can drive the frame to rotate around the axis to drive the multiple wheels to revolve around the axis.

[0026] In some embodiments of the present application, the false twisting machine in the first electrode device and the false twisting machine in the second electrode device have the same rotation direction and the same rotation speed.

[0027] In some embodiments of the present application, the conductive component includes:

[0028] a first conductive element electrically connecting the power supply unit and the rack;

[0029] A second conductive element is provided on the rotating shaft of the rotating wheel, and the second conductive element electrically connects the frame and the rotating wheel.

[0030] In some embodiments of the present application, the first electrode device and the second electrode device are symmetrically placed relative to a perpendicular line of the carbon fiber, and the power supply unit, the first electrode device, the carbon fiber, and the second electrode device form a current loop.

[0031] In some embodiments of the present application, the conveying wheel includes an input wheel and an output wheel, and the input wheel and the output wheel can rotate on their own, and the rotation in the direction with the carbon fiber as the axis of rotation is restricted, and the carbon fiber passes through the input wheel, the first electrode device, the auxiliary heating device, the second electrode device and the output wheel in sequence; the rotating wheel, the input wheel and the output wheel all have a twist-resistant effect on the carbon fiber wound thereon, and the carbon fiber is forward twisted between the input wheel and the first electrode device, the twist number is kept unchanged between the first electrode device and the second electrode device, and is reverse twisted between the second electrode device and the output wheel, and the reverse twist number is equal to the forward twist number. The carbon fiber is untwisted to an untwisted state and output by the output wheel.

[0032] Compared with the prior art, the advantages and positive effects of this application are:

[0033] (1) The dual-power heating system for graphitizing carbon fibers provided in at least one embodiment of the present application adopts two heating methods to heat the carbon fibers at the same time. The advantages of the two heating methods complement each other and together achieve an ultra-high temperature environment for graphitizing carbon fibers with lower energy consumption. The temperature inside and on the surface of the carbon fiber bundles is balanced, thereby improving the "skin-core" problem of the graphitized carbon fibers.

[0034] (2) The carbon fiber graphitization dual-power heating system provided in at least one embodiment of the present application adopts two heating methods to heat the carbon fiber at the same time. Compared with the existing single heating method, it reduces the requirements for heating equipment and technical conditions, greatly reduces the extreme working conditions of the heating equipment, avoids the consumption of a large amount of heating consumables, and thus greatly extends the life of the heating equipment to several years.

[0035] (3) The dual-power heating system for carbon fiber graphitization provided in at least one embodiment of the present application is based on electric heating, provides part of the energy in the form of current contact, and is combined with a contactless heating method for auxiliary heating. Only a small amount of energy is needed to further increase the temperature of the carbon fiber to the high temperature environment required for graphitization, thereby achieving a significant saving of electricity and carbon emissions to about 10% of the original.

[0036] (4) The carbon fiber graphitization dual-power heating system provided in at least one embodiment of the present application is based on electric heating and adopts a new radio frequency coupling heating method to better achieve high efficiency and energy saving, does not emit electromagnetic waves to the outside, avoids electromagnetic pollution, and is simple and easy to use.

[0037] (5) The carbon fiber graphitization dual-power heating system provided in at least one embodiment of the present application is based on electric heating and adopts a contactless heating method to accurately adjust the temperature of the carbon fiber filaments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] FIG1 is a schematic structural diagram of an embodiment of a dual-power heating system for carbon fiber graphitization provided by the present application;

[0040] FIG2 is a schematic structural diagram of another embodiment of the dual-power heating system for carbon fiber graphitization provided by the present application;

[0041] FIG3 is a schematic structural diagram of a coaxial coupler according to an embodiment of the present application;

[0042] FIG4 is a schematic structural diagram of an electrode device in an embodiment of the present application.

[0043] In the picture:

[0044] 1. Conveying wheel; 11. Input wheel; 12. Output wheel; 2. Electrode device; 201. First electrode device; 202. Second electrode device; 21. False twisting machine; 211. Frame; 2110. Chamber; 2111. Input port; 2112, output port; 212, rotor; 213, driving member; 22, conductive component; 221, first conductive element; 222, second conductive element; 3, heating zone; 4, power supply unit; 5, auxiliary heating device; 6, graphite furnace; 7, radio frequency coupling device; 71, radio frequency generator; 72, matching device; 73, coaxial coupler; 7301, housing; 7302, core wire; 7303, carbon fiber segment; 731, first end of coaxial coupler; 732, second end of coaxial coupler; 74, transmission line; 741, first transmission line; 742, second transmission line; 743, third transmission line; 744, fourth transmission line; 75, voltage standing wave; 76, current standing wave; 761, current standing wave node; 81, first wire motion controller; 82, second wire motion controller; 9, carbon fiber; 40, unwinding machine; 50, wire collecting machine. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0046] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0047] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0048] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0049] As used herein, the terms "connect," "connected," and similar terms are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. A person skilled in the art will understand the specific meanings of the above terms in this application. As used herein, "plurality" refers to two or more.

[0050] In response to the problem in the existing technology that an ideal high-temperature production environment cannot be provided during the carbon fiber graphitization process, this application proposes a dual-power heating solution, which is based on the electric heating method and uses another heating method for auxiliary heating. The two heating methods cooperate with each other to achieve an ideal high-temperature production environment.

[0051] As shown in FIG1 and FIG2 , the dual-power heating system for carbon fiber graphitization proposed in the embodiment of the present application includes a conveying wheel 1 , an electric heating system, and an auxiliary heating device 5 .

[0052] At least two conveying wheels 1 are arranged along the production direction of the carbon fibers 9 to position and convey the carbon fibers 9 .

[0053] The energized heating system includes two electrode devices 2 and a power supply unit 4. The two electrode devices 2 are respectively a first electrode device 201 and a second electrode device 202. The first electrode device 201 and the second electrode device 202 are sequentially arranged in the conveying direction of the carbon fibers 9 and in contact with the carbon fibers 9. The first electrode device 201 and the second electrode device 202 are spaced apart to form a heating zone 3 between them. The positive and negative terminals of the power supply unit 4 are electrically connected to the first electrode device 201 and the second electrode device 202, respectively, and can apply current to the carbon fibers 9 through the first electrode device 201 and the second electrode device 202.

[0054] Electric heating is a contact heating method. The power supply unit 4 provides electrical energy and forms an electric circuit between the first electrode device 201, the carbon fiber 9, and the second electrode device 202. The mobile charge is evenly distributed on the cross section of the carbon fiber 9, providing heat energy for the entire cross section. Since graphite is a poor conductor of heat at high temperatures, it is easy to ensure the stability of the internal temperature of the carbon fiber 9, avoid the "skin-core" phenomenon, and improve the graphitization effect. Compared with the graphite furnace or radio frequency heating methods in the prior art, the temperature control method of electric heating is simple and convenient. The power supply unit 4 can specifically use an adjustable DC power supply. By adjusting the voltage of the power supply, the temperature of the carbon fiber 9 can be quickly, reliably and accurately controlled.

[0055] The first electrode device 201 and the second electrode device 202 are spaced a certain distance apart. The auxiliary heating device 5 is disposed in the heating zone 3 between the first electrode device 201 and the second electrode device 202 and can heat the carbon fibers 9 in a contactless manner.

[0056] The carbon fiber graphitization dual-power heating system provided in the above embodiment of the present application is based on electric heating, and another heating method is selected to assist in heating the carbon fiber 9. The electric heating provides a portion of energy in the form of current contact, so that the electric zone between the first electrode device 201 and the second electrode device 202 first reaches a basic temperature of about 2000°C. Since the temperature of the carbon fiber 9 has not yet reached an ultra-high temperature at this time, the requirements for the electrodes are relatively low and it is technically easy to implement. On the basis of electric heating, a non-contact heating device is set in the heating zone 3 between the first electrode device 201 and the second electrode device 202, and the carbon fiber 9 is auxiliary heated in a non-contact manner. Only a small amount of energy is needed to further increase the temperature of the carbon fiber to the high temperature environment required for graphitization on the basis of electric heating, thereby reducing the requirements for the heating equipment. The carbon fiber graphitization dual-power heating system of the embodiment of the present application has redesigned the heating system to meet the basic conditions of the two energy transmissions, while avoiding the contradiction and interference between the two heating methods, reducing the requirements for the equipment and technology of the two heating methods, integrating the advantages of the two heating methods, complementing each other, and achieving a more ideal high temperature environment.

[0057] In some embodiments, as shown in FIG1 , the auxiliary heating device 5 can be a graphite furnace 6. Within the heating zone 3, the carbon fibers 9 are further heated in the furnace cavity of the graphite furnace 6 while being electrically heated. The temperature of the carbon fibers 9 in the graphite furnace 6 can be higher than the temperature of the furnace cavity itself. Therefore, the auxiliary heating reduces the requirement for the temperature of the furnace cavity of the graphite furnace 6, significantly extending the life of the graphite furnace 6 and significantly reducing energy consumption.

[0058] In other embodiments, the auxiliary heating device 5 can be a radio frequency coupling device 7 (as shown in Figure 2), a microwave heating cavity, a plasma heating cavity or a laser tunnel. In a dual-power heating system that combines electric heating with contactless heating such as radio frequency and microwave, since the conditions and efficiency of electric current in transmitting electric energy are far better than those of radio frequency and microwave, radio frequency and microwave heating only need to solve the energy required for the carbon fiber 9 to reach ultra-high temperature from the base temperature, and the burden of heating equipment such as radio frequency and microwave will be greatly reduced. The working states of the two heating methods can avoid ultra-high temperature conditions. The combination of the two heating methods can achieve complementary advantages, and the high-temperature environment generated tends to be stable. The temperature inside and on the surface of the carbon fiber 9 is balanced, avoiding the "skin-core" phenomenon.

[0059] The dual-power heating system for carbon fiber graphitization of this application also provides an embodiment in which the auxiliary heating device 5 is a radio frequency coupling device 7. The structural schematic diagram of the heating system in this embodiment is shown in Figure 2. This embodiment also proposes an inductive radio frequency coupling heating scheme without electromagnetic wave emission, allowing both to simultaneously heat the carbon fibers 9 and avoid mutual interference. The following, in conjunction with Figure 2, describes in detail the dual-power heating system that integrates both electrical heating and radio frequency coupling heating.

[0060] In some embodiments, the RF coupling device 7 includes an RF generator 71 and a coaxial coupler 73. The RF generator 71 is used to provide electromagnetic oscillations, specifically, to provide electromagnetic oscillations with adjustable power. As shown in FIG3 , the coaxial coupler 73 includes a coaxially arranged shell 7301 and a core wire 7302. The core wire 7302 is located within the shell 7301 and is hollow in the axial direction. The shell 7301 and the core wire 7302 are connected to the RF generator 71 to generate electromagnetic oscillations on the shell 7301 and the core wire 7302. The shell 7301 and the core wire 7302 are located within the heating zone 3, and the carbon fiber 9 passes through the interior of the core wire 7302. The carbon fiber segment 7303 located within the core wire 7302 serves as a conductor wire and together with the shell 7301 and the core wire 7302 constitute the coaxial coupler 73. The electromagnetic oscillation induces an anti-phase oscillating current on the carbon fiber segment 7303 located within the core wire 7302 to heat the carbon fiber segment 7303.

[0061] In some embodiments, the wavelength of the electromagnetic oscillation standing wave in the electromagnetic oscillation is λ, the axial length of the coaxial coupler 73 is set to λ / 2, and the coaxial coupler 73 is located between two adjacent current standing wave nodes 761 of the electromagnetic oscillation standing wave. In this embodiment, only the carbon fiber segment 7303 located within the core wire 7302 is heated by the oscillating current, and the carbon fibers 9 located outside the length of the coaxial coupler 73 are not heated.

[0062] In some embodiments, the RF coupling device 7 further includes a matcher 72 , which is connected to the RF generator 71 . The matcher 72 can ensure that the RF generator 71 can effectively transmit energy to the load to provide maximum power transmission and minimum reflection loss.

[0063] In some embodiments, the RF coupling device 7 further includes a transmission line 74 connecting the RF generator 71 and the coaxial coupler 73 and / or connecting the matcher 72 and the coaxial coupler 73. The transmission line 74 can transmit electromagnetic oscillation signals. For example, the transmission line 74 can be a coaxial feeder. It is understood that the housing 7301 and the core wire 7302 in the coaxial coupler 73 are connected to the matcher 72 and the RF generator 72, respectively, via the transmission line 74.

[0064] In some embodiments, the two ends of the coaxial coupler 73 along the axial direction are respectively a first end 731 and a second end 732; one end of the transmission line 74 is connected to the matcher 72, and the other end is divided into two paths and respectively connected to the first end 731 and the second end 732 of the coaxial coupler 73, and the electromagnetic oscillation is divided into two paths of electromagnetic oscillation with the same frequency and phase via the transmission line 74 and then transmitted to the first end 731 and the second end 732 of the coaxial coupler 73 respectively; wherein, part of the transmission line 74 forms a loop with the coaxial coupler 73 and forms an electromagnetic oscillation standing wave on the loop, and the wavelength of the electromagnetic oscillation standing wave is λ, and the electromagnetic oscillation standing wave includes a voltage standing wave 75 and a current standing wave 76, and the axial length of the coaxial coupler 73 is set to λ / 2 and the coaxial coupler is located between two adjacent current standing wave nodes 761 of the electromagnetic oscillation standing wave, and the current standing wave 76 will induce an anti-phase standing wave current on the carbon fiber 9, so that the carbon fiber 9 will be heated by the current.

[0065] In the dual-power heating system of the above embodiment, the auxiliary heating device 5 uses a radio frequency coupling device 7 to assist in the power-on heating method to further heat the carbon fibers. The radio frequency coupling device 7 utilizes two electromagnetic oscillations of the same frequency, in phase, and propagating in opposite directions. The axial length of the coaxial coupler 73 is set to half a wavelength, generating stable voltage standing waves 75 and current standing waves 76 in the coaxial coupler 73. Based on the high-frequency oscillating current and voltage generated by the coaxial coupler 73, an induced current is generated on the carbon fibers located inside the coaxial coupler 73, thereby heating the carbon fibers 9 located between the first end 731 and the second end 732 of the coaxial coupler 73. The carbon fibers 9 located outside the length of the coaxial coupler 73 are not heated because the two electromagnetic oscillations of the same frequency, in opposite phase, and in the same propagation direction cancel each other out.

[0066] The purpose of the transmission line is to transmit electromagnetic oscillations to the coaxial coupler 73. Various transmission schemes are available. For example, in the embodiment shown in FIG2 , the transmission line 74 specifically includes a first transmission line 741, a second transmission line 742, a third transmission line 743, and a fourth transmission line 744. One end of the first transmission line 741 is connected to the matcher 72. The other end of the first transmission line 741 is split into two paths and connected to the second transmission line 742 and the third transmission line 743, respectively. The second transmission line 742 is connected to the first end 731 of the coaxial coupler 73, and the third transmission line 743 is connected to the second end 732 of the coaxial coupler 73 via the fourth transmission line 744. As shown in FIG2 , the second transmission line 742, the third transmission line 743, the fourth transmission line 744, and the coaxial coupler 73 form a ring-shaped loop. It is understood that the loop can also have other shapes. The axial length of the coaxial coupler 73 is λ / 2, and the coaxial coupler is located between two adjacent current standing wave nodes 761 of the electromagnetic oscillation standing wave.

[0067] In some embodiments, as shown in Figure 4 , each electrode assembly 2 includes a false twister 21 and a conductive assembly 22. The axis of the false twister 21 is coaxial with the carbon fibers 9. The false twister 21 is configured to allow the carbon fibers 9 to pass along the axis and rotate relative to the axis to twist the carbon fibers 9. The conductive assembly 22 connects the power supply unit 4 and the false twister 21 and conducts current from the power supply unit 4 to the false twister 21. The false twister 21 applies a predetermined twist to the carbon fibers 9 and heats them within the heating zone 3. Heating the carbon fibers 9 while still twisted ensures a uniform flow of current across the fiber bundle, preventing sparks between the carbon fibers 9 during heating, which could affect product quality and improve the processing quality of the carbon fibers 9. The false twister 21 and the conductive assembly 22 together form the electrode assembly 2, conducting current from the power supply unit 4 to the carbon fibers 9, forming a current loop. It is understood that when the false twister 21 is rotating at zero speed, the carbon fibers 9 can be heated without twist. Whether to use twisted or untwisted heating can be determined based on actual production needs.

[0068] In some embodiments, the false twisting machine 21 includes a frame 211 , a plurality of rotating wheels 212 disposed in the frame 211 , and a driving member 213 . The interior of the frame 211 has a chamber 2110, and the frame 211 includes an input port 2111 and an output port 2112 arranged at both ends of the frame 211 in sequence along the conveying direction of the carbon fiber 9. The carbon fiber 9 enters the chamber 2110 through the input port 2111 and is output to the outside of the chamber 2110 through the output port 2112; multiple runners 212 are arranged in the chamber 2110 and connected to the frame 211, and the multiple runners 212 are respectively arranged on both sides of the axis. The two runners at both ends of the multiple runners 212 are tangent to the axis. The carbon fiber 9 passes around the multiple runners 212 in sequence and can drive the multiple runners 212 to rotate. The multiple runners 212 are conductive and can conduct current to the carbon fiber 9; the driving member 213 can drive the frame 211 to rotate around the axis to drive the multiple runners 212 to revolve around the axis, and the carbon fiber 9 is twisted by the revolution of the runners 212.

[0069] In the embodiment shown in Figure 4, four rotating wheels 212 are provided within the frame 211. The carbon fibers 9 enter the frame 211 along the axis through the input port 2111, sequentially wind around the four rotating wheels 212, and exit the false twisting machine 21 along the axis through the output port 2112. It is understood that the number of rotating wheels 212 is not limited to four, and may also be other numbers, such as three or five, depending on actual needs.

[0070] In some embodiments, the conductive assembly 22 includes a first conductive element 221 and a second conductive element. The first conductive element 221 is electrically connected to the power supply unit 4 and the frame 211. The second conductive element 222 is disposed on the rotating shaft of the rotating wheel 212 and electrically connected to the frame 211 and the rotating wheel 212. The first conductive element 221 and the second conductive element 222 conduct current from the power supply unit 4 to the rotating wheel 212 and then to the carbon fibers 9, thereby electrically heating the carbon fibers 9.

[0071] The first conductive element 221 can be a main energized slip ring, and the second conductive element 222 can be a branch energized slip ring. The main energized slip ring is connected to the power supply unit 4 via a wire and is installed on the frame 211. It can transmit the current of the power supply unit 4 to the frame 211. The number of branch energized slip rings is the same as the number of the runners 212. Each runner 212 has a branch energized slip ring installed on its shaft. The branch energized slip ring is connected to the frame 211 and can transmit the current on the frame 211 to the runner 212. The runner 212 is conductive and thus transmits the current to the carbon fiber 9 in contact with it. The specific structure and working principle of the energized slip ring can be found in the prior art and will not be elaborated in this application.

[0072] The structures of the first electrode device 201 and the second electrode device 202 are the same as those of the electrode device 2 described above, and the first electrode device 201 and the second electrode device 202 are placed symmetrically relative to the vertical line of the carbon fiber 9. The power supply unit 4, the first electrode device 201, the carbon fiber 9 and the second electrode device 202 form a current loop.

[0073] In some embodiments, the false twister 21 in the first electrode device 201 and the false twister 21 in the second electrode device 202 have the same rotation direction and the same speed. Since the two false twisters 21 have the same speed, there is no relative movement between the two. Therefore, the carbon fiber 9 located before the first electrode device 201 in the conveying direction of the carbon fiber is twisted by the false twister 21 in the rotating first electrode device 201, and then the carbon fiber 9 is conveyed between the first electrode device 201 and the second electrode device 202 and maintains a stable twist, and will no longer be twisted or untwisted, thereby improving the quality of processing in the heating zone 3.

[0074] In some embodiments, the conveying wheel 1 includes an input wheel 11 and an output wheel 12. The input wheel 11 and the output wheel 12 can rotate on their own and are restricted from rotating in the direction of the carbon fiber 9 as the rotation axis. After being released by the pay-off machine 40, the carbon fiber 9 passes through the input wheel 11, the first electrode device 201, the auxiliary heating device 5, the second electrode device, and the output wheel 12 in sequence, and is then collected by the take-up machine 50. The input wheel 11, the first electrode device 201, the auxiliary heating device 5, the second electrode device, and the output wheel 12 are arranged in a straight line in sequence, so that the carbon fiber 9 is conveyed and processed as a whole along the straight line.

[0075] The input wheel 11, the rotating wheel 212 and the output wheel 12 all have a twist-resisting effect on the carbon fiber 9. Specifically, the carbon fiber 9 is smoothly twisted as the rotating wheel 212 revolves.

[0076] Specifically, since the radial movement of the two ends of the carbon fiber 9 in the longitudinal direction is fixed by the input wheel 11 and the output wheel 12, the carbon fiber 9 is forward twisted between the input wheel 11 and the first electrode device 201. Since the rotation speeds of the two false twisters 21 in the first electrode device 201 and the second electrode device 202 are the same, the twist number of the carbon fiber 9 between the first electrode device 201 and the second electrode device 202 remains unchanged, and it is reversely twisted between the second electrode device 202 and the output wheel 12, and the reverse twist number is equal to the twist number of the previous forward twisting. The carbon fiber 9 is untwisted to an untwisted state and output by the output wheel 12, realizing untwisted input, twisted processing and untwisted output of the carbon fiber 9, thereby improving the quality of the processed carbon fiber 9.

[0077] In some embodiments, the carbon fiber graphitization dual-power heating system also includes a first wire motion control machine 81 and a second wire motion control machine 82, the input wheel 11 is set on the first wire motion control machine 81, and the output wheel 12 is set on the second wire motion control machine 82. The first wire motion control machine 81 and the second wire motion control machine 82 can control the movement of the carbon fiber 9. The specific structure can refer to the existing technology and will not be repeated in this application.

[0078] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0079] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the same. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present application. They should all be included in the scope of the technical solutions for which protection is requested in the present application.

Claims

1. A carbon fiber graphitization dual-power heating system, characterized in that: include: Two or more conveying wheels, which are arranged along the production direction of the carbon fiber to position and convey the carbon fiber; Two electrode devices, namely a first electrode device and a second electrode device, the first electrode device and the second electrode device are sequentially arranged in the conveying direction of the carbon fiber and in contact with the carbon fiber, and the first electrode device and the second electrode device are spaced apart to form a heating zone between the first electrode device and the second electrode device; a power supply unit, whose positive and negative ends are electrically connected to the first electrode device and the second electrode device respectively and can apply current to the carbon fiber via the first electrode device and the second electrode device; The auxiliary heating device is arranged in the heating zone and can heat the carbon fiber in a non-contact manner.

2. The carbon fiber graphitization dual-power heating system according to claim 1 is characterized in that: The auxiliary heating device is a graphite furnace, a radio frequency coupling device, a microwave heating cavity, a plasma heating cavity or a laser tunnel.

3. The carbon fiber graphitization dual-power heating system according to claim 2, characterized in that: The auxiliary heating device is a radio frequency coupling device, and the radio frequency coupling device includes: A radio frequency generator for providing electromagnetic oscillations; A coaxially arranged shell and core wire, wherein the core wire is located in the shell and is hollow inside along the axial direction, the shell and the core wire are connected to the radio frequency generator to generate electromagnetic oscillations on the shell and the core wire, the shell and the core wire are arranged in the heating zone and the carbon fiber passes through the inside of the core wire, the carbon fiber segment located inside the core wire serves as a conductor wire and together with the shell and the core wire constitutes a coaxial coupler, the electromagnetic oscillation induces an anti-phase oscillating current on the carbon fiber segment located inside the core wire to heat the carbon fiber segment.

4. The carbon fiber graphitization dual-power heating system according to claim 3 is characterized in that: The wavelength of the electromagnetic oscillation standing wave in the electromagnetic oscillation is λ, the axial length of the coaxial coupler is set to λ / 2 and the coaxial coupler is located between two adjacent current standing wave nodes of the electromagnetic oscillation standing wave.

5. The carbon fiber graphitization dual-power heating system according to claim 1, characterized in that: Each of the electrode devices comprises: A false twisting machine, whose axis is coaxial with the carbon fiber, and the false twisting machine is configured to allow the carbon fiber to pass along the axis and to rotate relative to the axis to twist the carbon fiber; A conductive component connects the power supply unit and the false twisting machine and can conduct current from the power supply unit to the false twisting machine.

6. The carbon fiber graphitization dual-power heating system according to claim 5, characterized in that: The false twisting machine comprises: A frame having a chamber therein, the frame comprising an input port and an output port sequentially arranged at two ends of the frame along a conveying direction of the carbon fiber, the carbon fiber enters the chamber through the input port and is output to the outside of the chamber through the output port; A plurality of rotating wheels are arranged in the chamber and connected to the frame, the plurality of rotating wheels are respectively arranged on both sides of the axis, two rotating wheels located at both ends of the plurality of rotating wheels are tangent to the axis, the carbon fiber passes through the plurality of rotating wheels in sequence and can drive the plurality of rotating wheels to rotate, and the plurality of rotating wheels are conductive; A driving member can drive the frame to rotate around the axis to drive the multiple rotating wheels to revolve around the axis.

7. The carbon fiber graphitization dual-power heating system according to claim 6, characterized in that: The false twisting machine in the first electrode device and the false twisting machine in the second electrode device rotate in the same direction and at the same speed.

8. The carbon fiber graphitization dual-power heating system according to claim 6, characterized in that: The conductive component comprises: A first conductive element electrically connecting the power supply unit and the rack; The second conductive element is arranged on the rotating shaft of the rotating wheel, and the second conductive element electrically connects the frame and the rotating wheel.

9. The carbon fiber graphitization dual-power heating system according to claim 8, characterized in that: The first electrode device and the second electrode device are symmetrically placed relative to a vertical line of the carbon fiber, and the power supply unit, the first electrode device, the carbon fiber and the second electrode device form a current loop.

10. The carbon fiber graphitization dual-power heating system according to claim 9, characterized in that: The conveying wheel includes an input wheel and an output wheel, the input wheel and the output wheel can rotate, and the rotation in the direction of the carbon fiber as the rotation axis is restricted, the carbon fiber passes through the input wheel, the first electrode device, the auxiliary heating device, the second electrode device and the output wheel in sequence; the rotating wheel, the input wheel and the output wheel all have a twist-resistant effect on the carbon fiber wound thereon, the carbon fiber is forward twisted between the input wheel and the first electrode device, the twist number is kept unchanged between the first electrode device and the second electrode device, and the carbon fiber is reversely twisted between the second electrode device and the output wheel, and the reverse twist number is equal to the forward twist number, and the carbon fiber is untwisted to a twist-free state and output by the output wheel.

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