A carbon fiber ultra-long and wide pre-oxidation furnace

Abstract

A carbon fiber ultra-long and wide-width pre-oxidation furnace includes a furnace body with an internal cavity for multiple layers of fibers. At both the inlet and outlet ends of the furnace body are inlets and outlets for fiber hot air sealing devices. The inlets and outlets of the fiber hot air sealing devices have running channels with the same number of fiber layers. These running channels are connected to the furnace cavity. The furnace body is a wide-width furnace body, consisting of several sections from the fiber hot air sealing device inlet to the fiber hot air sealing device outlet. Flexible expansion joints connect adjacent sections to compensate for thermal expansion along the length. The furnace is equipped with several sets of cleaning devices, several sets of heating zones, and several sets of circulating fans. The ultra-long and wide-width design significantly increases the feed rate and production capacity. The design employs vertical airflow distribution and high circulating wind speed, providing uniform temperature in both the horizontal and vertical directions and high output.

Description

Technical Field

[0001] This utility model relates to the field of fiber filament production equipment, and in particular to a carbon fiber ultra-long and wide pre-oxidation furnace. Background Technology

[0002] Carbon fiber is a high-performance fiber material with a carbon content of over 90%. Carbon fiber and its composites possess a series of excellent properties, including high specific strength, high specific modulus, high temperature resistance, corrosion resistance, fatigue resistance, extrusion resistance, electrical conductivity, thermal conductivity, and a low coefficient of thermal expansion. They can function as structural load-bearing materials and functional materials, hence the rapid development of carbon fiber and its composites in recent years. The main processes for preparing carbon fiber include the production of precursor fibers, pre-oxidation, carbonization, surface treatment, and winding, each of which significantly impacts the quality of the carbon fiber. Pre-oxidation refers to the necessary pre-oxidation process before carbonization of the precursor fibers, and the pre-oxidation furnace is a key piece of equipment in this process. During the pre-oxidation process in the furnace, a series of chemical changes occur on the surface of the precursor fibers, improving their properties. Simultaneously, the temperature field and temperature gradient distribution within the furnace cavity must be uniform. Therefore, improving the uniformity of airflow and temperature within the furnace cavity is crucial for reducing carbon fiber costs and improving quality.

[0003] Existing technologies for carbon fiber pre-oxidation furnaces suffer from drawbacks such as low feed rate of precursor fibers and low production capacity. Common issues include poor heat exchange in the inner layer of the fiber, slow heat exchange rate, susceptibility to ignition due to heat accumulation in the inner layer, poor temperature uniformity in both the transverse and longitudinal directions, and long fiber residence time and distance, all contributing to low production capacity. This is the biggest drawback of existing technologies and a problem that needs to be overcome in this field. Utility Model Content

[0004] The technical problem to be solved by this utility model is to address the shortcomings of the existing technology by proposing a carbon fiber ultra-long and wide pre-oxidation furnace that can significantly increase production capacity and improve fiber quality.

[0005] The technical problem to be solved by this utility model is achieved through the following technical solution: a carbon fiber ultra-long and wide pre-oxidation furnace, characterized by:

[0006] The furnace includes a furnace body, the interior of which is a furnace cavity for the operation of multiple layers of fiber filaments. At both the inlet and outlet ends of the furnace body are inlets and outlets for fiber filament hot air sealing devices. The inlets and outlets of the fiber filament hot air sealing devices have operating channels with the same number of fiber filament layers inside, and these operating channels are connected to the front and rear of the furnace cavity.

[0007] The furnace body is a wide furnace body, consisting of several sections from the inlet of the fiber hot air sealing device to the outlet of the fiber hot air sealing device, with flexible expansion joints connecting adjacent sections.

[0008] The flexible expansion joint includes a frame with a bending structure on its circumferential cross-section. The two ends of the bending structure are connected to the furnace plates on both sides in the length direction. The change in the distance between the furnace plates on both sides in the length direction is compensated for by the elastic deformation caused by the bending structure being squeezed.

[0009] It is equipped with several sets of cleaning devices, several sets of heating zones, and several sets of circulating fan devices.

[0010] The heating temperature zone includes two high-temperature heating temperature zones located at both ends and several groups of medium-temperature heating temperature zones located in the middle of the furnace cavity.

[0011] Each heating zone is equipped with an adjustable temperature heater, and a circulating fan unit is installed corresponding to each heater.

[0012] A lower airflow distribution plate is provided at the bottom of the operating channel, and an upper airflow distribution plate is provided at the top of the operating channel. The hot air outlet of the heater is positioned directly opposite the lower airflow distribution plate to form a hot air circulation perpendicular to the fiber bundle.

[0013] The technical problem to be solved by this utility model can also be further achieved through the following technical solutions: the circulating fan speed is ≥0.5m / s, and the temperature fluctuation in the furnace cavity 6 is within ±2℃.

[0014] The technical problem to be solved by this utility model can also be further achieved through the following technical solution: the distance between two adjacent operating channels is ≤220mm.

[0015] The technical problem to be solved by this utility model can also be further achieved through the following technical solution: a fire sprinkler structure is provided, including a PLC control system, a fire sprinkler device, a temperature detection system, and a heater.

[0016] The technical problem to be solved by this utility model can also be further achieved through the following technical solution: the cleaning device includes an oxidation furnace filter, which is installed below the circulating fan and heater on the side of the furnace cavity.

[0017] Compared to existing technologies, the pre-oxidation furnace features an ultra-long and wide design, significantly increasing the feed rate and production capacity. It has an internal furnace chamber capable of supporting more than 11 layers of fibers, employing an upper and lower airflow distribution and high circulating wind speed design. This allows for rapid heat exchange between the inner and outer layers of the fiber, preventing combustion due to heat buildup in the inner layers. Furthermore, it offers advantages such as uniform temperature in both the horizontal and vertical directions and high output, thus contributing to improved fiber quality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 is Figure 1 A longitudinal sectional view;

[0020] Figure 3 Temperature distribution map;

[0021] Figure 4 This is a structural diagram of a flexible expansion joint;

[0022] Figure 5 for Figure 4 View from direction A;

[0023] Figure 6 To clean up the structure diagram online. Detailed Implementation

[0024] The following combination Figures 1 to 5 The technical solutions in the embodiments of this utility model are described clearly and completely in further detail. Clearly, this is an ultra-long and wide pre-oxidation furnace for carbon fiber, including a furnace body with an effective heating length of 17 meters, an effective heating width of 4 meters, a raw fiber feeding amount of 1400 kg, 5 sets of modular ultra-long and wide pre-oxidation furnaces, and an internal furnace cavity capable of supporting 11 layers of fiber. The described embodiments are some, but not all, embodiments of this utility model. This application discloses an ultra-long and wide pre-oxidation furnace for carbon fiber.

[0025] A carbon fiber ultra-long and wide-width pre-oxidation furnace includes a furnace body with an internal cavity for multiple layers of fibers. At both the inlet and outlet ends of the furnace body are inlets and outlets for a hot air sealing device for the fibers. The inlets and outlets of the hot air sealing device for the fibers have running channels with the same number of fiber layers inside, and these running channels are connected to the front and rear of the furnace cavity.

[0026] The furnace body is a wide furnace body, consisting of several sections from the inlet of the fiber hot air sealing device to the outlet of the fiber hot air sealing device, with flexible expansion joints connecting adjacent sections.

[0027] The flexible expansion joint includes a frame with a bending structure on its circumferential cross-section. The two ends of the bending structure are connected to the furnace plates on both sides in the length direction. The change in the distance between the furnace plates on both sides in the length direction is compensated for by the elastic deformation caused by the bending structure being squeezed.

[0028] It is equipped with several sets of cleaning devices, several sets of heating zones, and several sets of circulating fan devices.

[0029] The heating temperature zone includes two high-temperature heating temperature zones located at both ends and several groups of medium-temperature heating temperature zones located in the middle of the furnace cavity.

[0030] Each heating zone is equipped with an adjustable temperature heater, and a circulating fan unit is installed corresponding to each heater.

[0031] A lower airflow distribution plate is provided at the bottom of the operating channel, and an upper airflow distribution plate is provided at the top of the operating channel. The hot air outlet of the heater is positioned directly opposite the lower airflow distribution plate to form a hot air circulation perpendicular to the fiber bundle.

[0032] The circulating fan speed is ≥0.5m / s, and the temperature fluctuation inside furnace cavity 6 is within ±2℃.

[0033] The distance between two adjacent running channels is ≤220mm.

[0034] It is equipped with a fire sprinkler system, including a PLC control system, fire sprinkler devices, a temperature detection system, and a heater.

[0035] The cleaning device includes an oxidation furnace filter, which is located below the circulating fan and heater on the side of the furnace chamber.

[0036] like Figure 1 , 2 The diagram shows the overall structure of a carbon fiber ultra-long and wide pre-oxidation furnace. In the diagram: 1 furnace body, 2 fiber filament hot air sealing device inlet, 3 fiber filament hot air sealing device outlet, 4 air inlet, 5 waste outlet, 6 furnace cavity, 7 airflow upper distribution, 8 airflow upper distribution plate.

[0037] The furnace includes a furnace body 1, which has an internal furnace cavity 6 for running 11 or more layers of fiber filaments. When the fiber filaments run in the furnace cavity 6, the furnace body 1 has a fiber filament hot air sealing device inlet 2 and a fiber filament hot air sealing device outlet 3 at both ends. The fiber filament hot air sealing device inlet 2 and fiber filament hot air sealing device outlet 3 have running channels with the same number of fiber filament layers inside. The running channels are connected to the furnace cavity 6 front and back, and the distance between two adjacent running channels is ≤220mm. The furnace cavity 6 is equipped with 5 sets of cleaning devices, 5 sets of heating temperature zones, and 5 sets of circulating fan devices. The circulating fan speed is ≥0.5m / s, which can keep the temperature fluctuation in the furnace cavity 6 within ±2℃. The circulating fan blows the circulating air heated by the heater from the bottom of the furnace cavity upward into the furnace cavity 6 through the upward airflow distribution, and then the furnace cavity 6 draws in the heater and circulating fan through the downward airflow distribution, repeating the cycle to achieve a circulating air path. The fiber filaments of this invention travel in a left-to-right direction, and the circulating hot air is blown in a direction perpendicular to the fiber filaments and densely arranged. Therefore, the temperature of each point on the fiber filaments that receives air is the same, and the hot air in the vertical direction can penetrate the fiber filaments. Thus, this invention has the advantages of rapid heat exchange between the inner and outer layers of the fiber filaments, no combustion due to heat accumulation in the inner layer, uniform temperature in both the horizontal and vertical directions, flexible fiber filament spacing, low residence time, low residence distance, and high output.

[0038] like Figure 3 As shown, there are: 9 heater chambers, 10 heaters (800KW), and 11 heaters (500KW).

[0039] The heaters for the different temperature zones have different structures and powers. The two ends use 800KW heaters and the middle uses 500KW heaters. This combination of strengths and weaknesses ensures uniformity of hot air temperature and airflow in each zone and reduces the difficulty of commissioning.

[0040] like Figure 4 , 5 The diagram shows a flexible expansion joint structure for a carbon fiber ultra-long and wide pre-oxidation furnace, comprising: a frame; a bending structure 13 on the circumferential cross-section of the frame, the bending structure being composed of continuous rectangular grooves, and connecting edges 12 at both ends of the bending structure being connected to furnace plates on both sides along the length direction; wherein, when the distance between the furnace plates on both sides along the length direction changes, the bending structure is compressed and undergoes elastic deformation, compensating for thermal expansion in the length direction. Alternatively, the furnace plates at both ends along the length direction of the pre-oxidation furnace can be fixed ends, the middle section can be an expansion section, and the flexible structure can be set between the fixed ends and the expansion section, with insulation material filling the space between the frame and the outer wall. This design can maintain good sealing of the furnace body, reduce heat loss, and improve the thermal efficiency of the pre-oxidation furnace.

[0041] A fire sprinkler structure diagram for an ultra-long and wide carbon fiber pre-oxidation furnace includes a PLC control system, a fire sprinkler device, a temperature detection system, and a heating component. The PLC control system 1 monitors signals from the temperature detection system in real time to determine the fire risk factor K within the furnace. When this risk factor reaches a predetermined threshold, the PLC control system 1 controls the fire sprinkler device 2 to spray, simultaneously cutting off the power supply to the heater 4 and activating the electrically controlled fire sprinkler valves to perform the fire sprinkler action.

[0042] like Figure 6 The diagram shows an online cleaning structure for an ultra-long and wide carbon fiber pre-oxidation furnace. The furnace filter is located on the side of the furnace cavity, below the circulating fan and heater. Its function is to filter out impurities brought in by the circulating air, preventing them from participating in the circulation and affecting the carbon fiber pre-oxidation process, thus ensuring the pre-oxidation quality of the carbon filaments. Cleaning the filter requires opening the sealing cover 20, removing the sealing plug 19, and then taking out the filter screen 18 for cleaning. After cleaning, the filter screen must be put back. The entire process is time-saving and labor-saving, with short opening times and small gaps, minimizing the impact on the furnace temperature and making it easier to ensure the quality of the carbon filaments.

[0043] In summary, the embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although other parts of this utility model may be described and modified in detail with reference to the foregoing embodiments, or some technical features may be replaced with equivalent ones, those skilled in the art should understand that all equivalent structural changes made by those skilled in the art using the specification and claims of this utility model should be included within the protection scope of this utility model.

Claims

1. A carbon fiber ultra-long and wide-width pre-oxidation furnace, characterized in that: The furnace includes a furnace body, the interior of which is a furnace cavity for the operation of multiple layers of fiber filaments. At both the inlet and outlet ends of the furnace body are inlets and outlets for fiber filament hot air sealing devices. The inlets and outlets of the fiber filament hot air sealing devices have operating channels with the same number of fiber filament layers inside, and these operating channels are connected to the front and rear of the furnace cavity. The furnace body is a wide furnace body, consisting of several sections from the inlet of the fiber hot air sealing device to the outlet of the fiber hot air sealing device, with flexible expansion joints connecting adjacent sections. The flexible expansion joint includes a frame with a bending structure on its circumferential cross-section. The two ends of the bending structure are connected to the furnace plates on both sides in the length direction. The change in the distance between the furnace plates on both sides in the length direction is compensated for by the elastic deformation caused by the bending structure being squeezed. It is equipped with several sets of cleaning devices, several sets of heating zones, and several sets of circulating fan devices. The heating temperature zone includes two high-temperature heating temperature zones located at both ends and several groups of medium-temperature heating temperature zones located in the middle of the furnace cavity. Each heating zone is equipped with an adjustable temperature heater, and a circulating fan unit is installed corresponding to each heater. A lower airflow distribution plate is provided at the bottom of the operating channel, and an upper airflow distribution plate is provided at the top of the operating channel. The hot air outlet of the heater is positioned directly opposite the lower airflow distribution plate to form a hot air circulation perpendicular to the fiber bundle.

2. The carbon fiber ultra-long and wide-width pre-oxidation furnace according to claim 1, characterized in that: The circulating fan speed is ≥0.5m / s, and the temperature fluctuation inside the furnace cavity is within ±2℃.

3. The carbon fiber ultra-long and wide-width pre-oxidation furnace according to claim 1, characterized in that: The cleaning device includes an oxidation furnace filter, which is located below the circulating fan and heater on the side of the furnace chamber.

4. The carbon fiber ultra-long and wide-width pre-oxidation furnace according to claim 1, characterized in that: The distance between two adjacent running channels is ≤220mm.

5. The carbon fiber ultra-long and wide-width pre-oxidation furnace according to claim 1, characterized in that: It is equipped with a fire sprinkler system, including a PLC control system, fire sprinkler devices, a temperature detection system, and a heater.

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