Device for synchronously measuring pre-oxidation temperature and tension of polyacrylonitrile-based large-tow carbon fiber precursor
By designing a device including a sample making mold and a tension measuring device, the problem of temperature and tension monitoring of large tow fibers during pre-oxidation is solved, accurate measurement is achieved, and production safety and product quality are improved.
Patent Information
- Application Number
- CN202510168064.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-17
- Publication Date
- 2025-07-08
AI Technical Summary
The prior art is difficult to conduct real-time and accurate temperature and tension monitoring of large tow polyacrylonitrile-based fibers during pre-oxidation, resulting in limitations in production control and product quality stability.
A device including sample making mold and tension measuring device is designed, and the temperature and tension are measured by thermocouples. It uses 304 stainless steel material, which is simple in structure and can work stably in a high temperature environment to meet the measurement needs of different specifications of tows.
Accurate measurement of the internal temperature and tension of large tow fibers is achieved, production guidance is provided, and production safety and product quality stability are improved.
Smart Images
Figure CN120274901A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of pre-oxidation of polyacrylonitrile-based large-tow carbon fiber precursor fibers, and in particular to a device for synchronously measuring pre-oxidation temperature and tension of polyacrylonitrile-based large-tow precursor fibers. Background Art
[0002] In the carbon fiber production process, the pre-oxidation treatment of polyacrylonitrile (PAN)-based fibers is a crucial step, which directly affects the final performance and quality of the carbon fiber. Polyacrylonitrile fibers are converted into high-strength, high-modulus carbon fibers through pre-oxidation, carbonization, graphitization and other processes. Temperature control during the pre-oxidation process is particularly important. In this process, polyacrylonitrile fibers are heated in air at 200 to 300°C to stabilize the fiber structure through chemical reactions to ensure that it no longer melts or burns. However, the pre-oxidation process is accompanied by a large amount of heat release, especially for large-tow polyacrylonitrile fibers. Because of their large fiber bundles and poor heat dissipation, heat accumulation is more serious, which can easily lead to local overheating and increase the risk of production accidents.
[0003] At present, although some equipment can be used to measure the temperature of a single fiber, there are still certain difficulties in real-time and accurate monitoring of the internal temperature of large tow fibers. Traditional temperature measurement methods mostly rely on external temperature detection and cannot effectively reflect the changes in the internal temperature of the fiber bundle, which has certain limitations in controlling and optimizing the pre-oxidation process and ensuring the stability of fiber quality. Therefore, it is particularly urgent to develop a device that can synchronously measure the temperature and tension of large tow polyacrylonitrile-based fibers during the pre-oxidation process. This device can not only realize the precise monitoring of the internal temperature of large tows, but also measure the tension changes in real time, providing an important basis for further optimizing the production process, improving production safety and the quality of the final product. Summary of the invention
[0004] The present application provides a device for synchronously measuring the pre-oxidation temperature and tension of polyacrylonitrile-based large-tow carbon fiber precursor, so as to test the internal temperature and process tension of large-tow fibers. By measuring tows of different specifications, guidance can be provided for actual production.
[0005] This application provides a device for synchronously measuring the pre-oxidation temperature and tension of polyacrylonitrile-based large tow carbon fiber precursor filaments, including: a sample preparation mold (1), a tension measuring device (2); the sample preparation mold is composed of pin 1 (3), pin 2 (4), a lower frame (5), and an upper frame (6); the tension measuring device is composed of a dynamometer module (7), a dynamometer module fixing module (8), a connecting piece (9), a mold fixing block (10), and a hook extension rod (11). In the working state, the filament bundle (12) is wound around the sample preparation mold (1), a thermocouple (13) is buried inside, the sample preparation mold (1) is installed on the tension measuring device (2), and then it is sent into the pre-oxidation oven for real-time measurement of temperature and tension.
[0006] Preferably, the materials of all components of the device are 304 stainless steel. In the working state, the device has a high heating rate and will not overly interfere with the temperature stability in the furnace; when the ambient temperature is 200 - 300 °C and the filament bundle (12) reacts to produce a large shrinkage, the device will not deform, ensuring the credibility of the tension measurement data.
[0007] Preferably, the sample preparation mold (1) of the device fixes the lower frame (5) and the upper frame (6) into a whole through pin 1 (3) and pin 2 (4), without the need for screw fastening.
[0008] Preferably, the length and width of the sample preparation mold (1) of the device are 50 mm * 173 mm. In the working state, it can meet the test requirements of a filament bundle with a maximum width expansion of 40 mm.
[0009] Preferably, for the tension measuring device (2) of the device, the relative positions of the dynamometer module fixing module (8) and the connecting piece (9), and the relative positions of the connecting piece (9) and the mold fixing block (10) can be adjusted. In the working state, the relative position of the dynamometer and the measuring filament bundle can be flexibly adjusted according to the experimental variables.
[0010] Preferably, for the tension measuring device (2) of the device, the length of the hook extension rod (11) can be adjusted. In the working state, it can meet the tension measurement requirements for the situation after the relative position between the dynamometer and the measuring filament bundle changes.
[0011] Preferably, for the tension measuring device (2) of the device, the relative positions of the dynamometer module (7) and the dynamometer module fixing module (8) can be adjusted and fastened with a wing nut. In the working state, a pre-tension can be applied to the filament bundle before the device is sent into the pre-oxidation oven.
[0012] Preferably, for the tension measuring device (2) of the device, there is a circular partition on the mold fixing block (10). In the working state, this partition is located between the pre-oxidation oven and the dynamometer, which can block most of the pre-oxidation high-temperature air flow. At the same time, there are holes on the partition to maintain smooth internal and external air circulation.
[0013] Preferably, in the working state, both ends of the lower frame (5) and the upper frame (6) clamp the tow with iron sheets and are fastened with screws, which can prevent the slippage caused by the shrinkage of the tow reaction.
[0014] Preferably, in the working state, after the pin 1 (3) and the pin 2 (4) of the sample preparation mold (1) of the device are removed, the tow obtains a degree of freedom in the axial direction, and accurate and reliable tension data can be obtained.
[0015] Compared with the prior art, the present application has the following advantages:
[0016] The present application provides a device for synchronously measuring the pre-oxidation temperature and tension of polyacrylonitrile-based large tow carbon fiber precursor, including: a sample preparation mold (1), a tension measuring device (2); the sample preparation mold is composed of a pin 1 (3), a pin 2 (4), a lower frame (5), and an upper frame (6); the tension measuring device is composed of a dynamometer module (7), a dynamometer module fixing block (8), a connecting piece (9), a mold fixing block (10), and a hook extension rod (11).
[0017] By using the above device, accurate temperature and tension measurements can be carried out on large tow fibers of different specifications, providing guiding data for production. The device has a simple structure, is easy to operate, has a length adjustment function, and can meet the application of more scenarios. Brief Description of the Drawings
[0018] Figure 1 is a schematic diagram of a device for synchronously measuring the pre-oxidation temperature and tension of polyacrylonitrile-based large tow carbon fiber precursor provided by the present application.
[0019] Figure 2 is a detailed schematic diagram of the sample preparation device.
[0020] Figure 3 is a detailed schematic diagram of the tension measuring device.
[0021] Figure 4 is a detailed schematic diagram of the device in the working state.
[0022] Figure 5 is the result temperature curve of Example 1.
[0023] Figure 6 is the result tension curve of Example 2. Detailed Description of the Embodiments
[0024] In order to make the structural principle and technical advantages of the present invention easier to understand, the following is further described in combination with specific examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0025] Example 1 (Installing pins to measure only the internal temperature of tows with different widths)
[0026] Wind the tow around the sample preparation mold (1), bury a thermocouple at the center inside the tow, install the sample preparation mold (1) on the tension measuring device (2), without removing pin 1 (3) and pin 2 (4), limit the degree of freedom of the fiber bundle to 0, and observe the readings of the thermocouple non-paper recorder.
[0027] The internal temperature conditions of the 48K tow at 10 mm, 20 mm, and 30 mm were experimentally tested, and the temperature change curves are shown in the attached drawings. It can be seen that as the width decreases, the internal temperature of the tow increases. When the width decreases from 20 mm to 10 mm, the tow temperature rises rapidly, indicating the instability of the reaction. The above results have clear regularity and can provide guidance for production.
[0028] Example 2 (Removing pins to measure only the process tension change of the tow)
[0029] Wind the tow around the sample preparation mold (1) to make a 48K large tow fiber, limit the width of the tow to 10 mm, install the sample preparation mold (1) on the tension measuring device (2), without removing pin 1 (3) and pin 2 (4), and give the fiber bundle a degree of freedom in the axial direction. Connect the dynamometer to the computer and observe the process tension change data.
[0030] The process tension change of the tow in four continuous temperature zones was experimentally tested, and the tension change curves are shown in the attached drawings. It can be seen from the figure the different tension change laws of the tow in the four temperature zones. For example, in the first temperature zone (OF1), the tow experienced a tension peak due to disorientation, and then the tension decreased due to the enhanced molecular chain mobility; in the subsequent temperature zones (OF2, OF3, OF4), as the reaction degree increased, the tow tension continuously increased with the progress of the reaction, and a rapid increase in tension during the cooling process was observed. The obtained data have strong regularity and good guiding significance.
Claims
1. An apparatus for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor, characterized in that, Including: Sample preparation mold (1), tension measurement device (2); The sample preparation mold consists of pin 1 (3), pin 2 (4), lower frame (5), and upper frame (6); the tension measurement device consists of a dynamometer module (7), a dynamometer module fixing module (8), a connecting piece (9), a mold fixing block (10), and a hook extension rod (11).
2. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, wherein, The materials of all components of the said device are 304 stainless steel.
3. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, characterized in that, The sample preparation mold (1) fixes the lower frame (5) and the upper frame (6) into a whole through pin 1 (3) and pin 2 (4), without screw fastening.
4. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, characterized in that, The tension measurement device (2) can adjust the relative positions of the dynamometer module fixing module (8) and the connecting piece (9), as well as the relative positions of the connecting piece (9) and the mold fixing block (10). Under working conditions, the relative position between the dynamometer and the measured wire bundle can be flexibly adjusted according to experimental variables.
5. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, characterized in that, The tension measurement device (2) can adjust the length of the hook extension rod (11). Under working conditions, it can meet the tension measurement requirements for the situation after the relative position between the dynamometer and the measured wire bundle changes.
6. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, wherein, In the tension measurement device (2), the relative position between the dynamometer module (7) and the dynamometer module fixing module (8) can be adjusted and fastened by a wing nut. Under working conditions, a pre-tension can be applied to the wire bundle before the device is sent into the pre-oxidation oven.
7. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, characterized in that, Under working conditions, both ends of the lower frame (5) and the upper frame (6) clamp the wire bundle with iron sheets and fasten them with screws to prevent slippage caused by the shrinkage of the wire bundle during the reaction.
8. The device for synchronously measuring the pre-oxidation temperature and tension of a polyacrylonitrile-based large tow carbon fiber precursor according to claim 1, wherein, Under working conditions, after removing pin 1 (3) and pin 2 (4) of the sample preparation mold (1) of the said device, the wire bundle obtains a degree of freedom in the axial direction, so as to obtain accurate and reliable tension data.