CN-121994874-A - Online detection device and method for carbonization rate of carbon fiber

CN121994874ACN 121994874 ACN121994874 ACN 121994874ACN-121994874-A

Abstract

The invention relates to the technical field of carbon fiber production and manufacturing, and particularly discloses an on-line detection device and method for carbon fiber carbonization rate; the device comprises a box body, a guide wheel set, a multichannel data acquisition device and a temperature acquisition assembly, wherein the box body is connected with a carbonization furnace through a connecting flange, the guide wheel set comprises two fiber bragg grating guide wheels and two electrode guide wheels which are respectively arranged at the front side, the rear side and the bottom between the two guide wheels and used for measuring tension, temperature and electricity, the temperature acquisition assembly is arranged on a fiber path between the two electrode guide wheels and used for measuring a space temperature field, the multichannel data acquisition device is used for acquiring voltage signals, the device is used for synchronously acquiring the voltage, the space temperature field, the tension and the contact point temperature signals of fibers, accordingly, dynamic compensation is carried out on an original resistance value, and carbonization rate is inverted and output.

Inventors

DING GUOPING
GAO YIZHE
YANG MINGHUI
SONG CHUNSHENG
CHEN XI
LIU WENCHANG

Assignees

武汉理工大学

Dates

Publication Date: 20260508
Application Date: 20260407

Claims (10)

1. The carbon fiber carbonization rate online detection device is characterized by comprising a box body (1), a guide wheel group (2), a multichannel data acquisition device (3) and a temperature acquisition assembly (4), wherein, One end of the box body (1) is provided with a connecting flange for connecting an external carbonization furnace; The guide wheel set (2) comprises a fiber grating guide wheel assembly (21) and an electrode guide wheel assembly (22) and is used for guiding and measuring running carbon fiber wires; The fiber bragg grating guide wheel assembly (21) comprises two fiber bragg grating guide wheel assemblies which are arranged on the front side and the rear side of the box body (1) along the running direction of the carbon fiber and are used for measuring the real-time tension of the carbon fiber; The electrode guide wheel assemblies (22) comprise two electrode guide wheel assemblies, are arranged between the fiber grating guide wheel assemblies (21) and are positioned at the bottoms of the two fiber grating guide wheel assemblies (21), and the two electrode guide wheel assemblies (22) are electrically connected with an external current source and are used for applying constant measurement current to carbon fiber wires; the multi-channel data acquisition device (3) is arranged outside the box body (1), and the detection end of the multi-channel data acquisition device (3) extends into the box body (1) and is electrically connected with the two electrode guide wheel assemblies (22) for applying current to the carbon fiber wires and leading out voltage measurement signals; The temperature acquisition assembly (4) is arranged on the carbon fiber wire path between the two electrode guide wheel assemblies (22) and is used for measuring the space temperature field of the carbon fiber wires.
2. The on-line detection device for carbon fiber carbonization rate according to claim 1, wherein the fiber grating guide wheel assembly (21) comprises a fixed mandrel (211), a rotary sleeve (212), a temperature compensation grating (213) and a force sensitive grating (214), wherein, Two ends of the fixed mandrel (211) are fixedly arranged on the inner wall of the box body (1); The rotary sleeve (212) is rotationally connected to the fixed mandrel (211) through symmetrically arranged bearings and is used for contacting and guiding the carbon fiber wires; The temperature compensation grating (213) is fixedly arranged on the fixed mandrel (211) and is in signal connection with an external demodulator for providing a temperature reference signal; the force-sensitive grating (214) is fixedly arranged on the fixed mandrel (211) and is positioned between the two bearings, and the force-sensitive grating (214) is in signal connection with an external demodulator and is used for sensing the axial strain of the fixed mandrel (211) caused by tension.
3. The on-line carbon fiber carbonization rate detection device according to claim 1, wherein the electrode guide wheel assembly (22) comprises an insulating guide wheel shaft (221) and a conductive wheel body (222), wherein, The insulating guide wheel shaft (221) is fixedly connected with the conductive wheel body (222) to form an integral electrode guide wheel; The conductive wheel body (222) is rotationally connected to the box body (1) through an insulating guide wheel shaft (221) and is used for contacting and guiding carbon fiber wires, and the outer surface of the conductive wheel body (222) is coated with a conductive coating; the conductive wheel body (222) is electrically connected with an external current source and is used for applying constant measurement current to the carbon fiber filaments; The detection end of the multichannel data acquisition device (3) is electrically connected with the conductive wheel body (222) and is used for measuring voltage signals between the two electrode guide wheel assemblies (22).
4. An on-line carbon fiber carbonization rate detection device according to claim 3, wherein the temperature acquisition assembly (4) comprises a mounting frame (41) and a temperature acquisition device (42), wherein, The mounting frame (41) is fixed in the box body (1) and spans between the conductive wheel bodies (222) of the two electrode guide wheel assemblies (22); The temperature collectors (42) comprise a plurality of temperature collectors which are fixed on the mounting frame (41) and are distributed at intervals along the running direction of the carbon fiber, and the temperature collectors (42) are in contact with or are arranged adjacent to the surface of the carbon fiber and are used for synchronously measuring the temperature of different positions of the carbon fiber between the two electrode guide wheel assemblies (22).
5. The carbon fiber carbonization online detection device according to claim 1, further comprising a drying oven (5); The drying box (5) is arranged at one end of the box body (1) connected with the external carbonization furnace, and a drying agent is filled in the drying box (5) and used for drying the entering carbon fiber filaments.
6. The on-line carbon fiber carbonization rate detection device according to claim 5, further comprising a constant temperature blow box (6); The air outlet of the constant temperature air blowing box (6) is communicated with the box body (1) and is used for injecting nitrogen into the box body (1) so as to blow off impurities attached to the surface of the carbon fiber filaments and construct a positive pressure environment, and the top of the box body (1) is provided with an exhaust outlet.
7. An on-line detection method for carbon fiber carbonization rate, characterized in that the on-line detection is performed by the on-line detection device for carbon fiber carbonization rate according to any one of claims 1 to 6, the detection method comprising: S1, a box body is connected with an outlet of an external high-temperature carbonization furnace in a sealing way through a connecting flange, so that carbon fiber wires produced by the high-temperature carbonization furnace are led into the box body through the connecting flange and sequentially wound on the upper side of a first fiber grating guide wheel assembly, the lower side of a first electrode guide wheel assembly, the lower side of a second electrode guide wheel assembly and the upper side of the second fiber grating guide wheel assembly to be led out; S2, carbon fiber wires firstly enter a drying box, the surface moisture of the carbon fiber wires is removed by using a drying agent in the drying box, then constant-temperature nitrogen is continuously introduced into the box through a constant-temperature air blowing box so as to blow off impurities attached to the surfaces of the carbon fiber wires, inhibit pyrolysis side reactions, and form a stable constant-temperature positive-pressure environment in the box, and the constant-temperature positive-pressure environment is used for discharging reaction waste gas and redundant gas through a waste gas outlet on the box; s3, applying microampere-level or milliamp-level constant current to the conductive wheel bodies of the two electrode guide wheel assemblies through an external current source to enable the current to flow through carbon fiber wires at the interval between the microampere-level or milliamp-level constant current and simultaneously synchronously collecting voltage signals between the two electrode guide wheel assemblies through a multichannel data collector; S4, connecting a temperature compensation grating and a force-sensitive grating in the fiber bragg grating guide wheel assembly with an external demodulator, collecting a temperature reference signal, a force-temperature composite strain signal and a temperature composite strain signal, and then obtaining real-time tension of the carbon fiber through decoupling calculation; S5, calculating an original resistance value based on the acquired voltage signal, and dynamically compensating the original resistance value by utilizing the real-time tension of the carbon fiber wire obtained by decoupling of an external demodulator and a space field temperature signal on a carbon fiber wire path between two electrode guide wheel assemblies to obtain a compensated resistance value; and S6, converting the obtained compensated resistance value based on the known relation between the resistivity and the carbonization rate of the carbon fiber, and obtaining a carbonization rate value.
8. The method for on-line detection of carbon fiber carbonization rate according to claim 7, wherein the method comprises the steps of connecting a temperature compensation grating and a force-sensitive grating in the fiber grating guide wheel assembly with an external demodulator, collecting a temperature reference signal, a force and temperature composite strain signal, and obtaining real-time tension of carbon fiber through decoupling calculation, and comprises the following steps: Synchronously demodulating the central wavelength drift amount of the temperature compensation grating and the sensitivity grating through an external demodulator; according to the central wavelength drift amount of the temperature compensation grating, a first temperature value of a contact point of the fiber grating guide wheel assembly and the carbon fiber wire is calculated, and a temperature influence component of the first temperature value on the central wavelength drift amount of the force-sensitive grating is calculated; Subtracting the temperature influence component from the central wavelength drift amount of the force-sensitive grating to obtain the strain wavelength drift amount only caused by the tension of the carbon fiber; And calculating the real-time tension of the carbon fiber according to the strain wavelength drift amount.
9. The method of claim 7, wherein the step of synchronously collecting the temperature signal of the spatial field on the carbon fiber wire path between the two electrode guide wheel assemblies by a plurality of temperature collectors in the temperature collection assembly comprises the steps of: And synchronously measuring the temperature of at least three different position points in the section between the two electrode guide wheel assemblies along the running direction of the carbon fiber wires on the section between the two electrode guide wheel assemblies so as to acquire a space field temperature signal of the section carbon fiber wires between the two electrode guide wheel assemblies.
10. The method for on-line detection of carbon fiber carbonization rate according to claim 7, wherein dynamically compensating the original resistance value to obtain a compensated resistance value comprises: and respectively determining a piezoresistive effect compensation coefficient and a temperature effect compensation coefficient according to the real-time tension and a space field temperature signal of the section carbon fiber yarn between the two electrode guide wheel assemblies, and correcting the original resistance value in real time based on the piezoresistive effect compensation coefficient and the temperature effect compensation coefficient to obtain a compensated resistance value.

Description

Online detection device and method for carbonization rate of carbon fiber Technical Field The invention relates to the technical field of carbon fiber production and manufacturing, in particular to an on-line detection device and method for carbon fiber carbonization rate. Background The carbon fiber is used as a high-performance material composed of carbon elements, and has become an indispensable key base material in the industrial field by virtue of the characteristics of high strength, high modulus, low density and excellent corrosion resistance and high temperature resistance, and the production process of the carbon fiber is complex, wherein the carbonization process is a core link for converting a precursor into the carbon fiber with high carbon content and ideal microcrystalline structure, and the key indexes such as mechanical property, conductive property and the like of a final product are directly determined. In the prior art, the voltammetry based on ohm's law is a core means which is widely researched and adopted, the method can directly calculate the resistance value of the carbon fiber by applying current to two ends of the carbon fiber and measuring the generated voltage drop, and then the resistivity is obtained by combining the geometric dimension of the fiber, and because the implementation principle is direct, the construction of a measuring system is relatively simple and the quick continuous measurement is easy to realize, the voltammetry-based resistance measurement is regarded as one of the most promising technical paths for realizing the online and real-time detection of the carbonization rate of the carbon fiber, and related research and industrial attempts are all conducted around the method. However, when the technology is applied to a continuous and dynamic industrial production line, fundamental challenges exist, when the carbon fiber moves at a high speed on the production line, resistance measurement values of the carbon fiber are comprehensively interfered by inherent environmental temperature fluctuation of the production line, self heating of measurement current and mechanical tension change of the fiber, and the interference factors are mixed with resistance change of the carbon fiber caused by change of carbonization degree, so that the existing online measurement device is difficult to accurately distinguish and strip interference signals, accurate carbonization rate data cannot be output in real time, and stable and reliable measurement results of the carbonization rate of the carbon fiber detected by the voltammetry method are difficult to obtain in an actual production environment. Disclosure of Invention Aiming at the technical problems in the prior art, the invention provides a device and a method for online detection of carbon fiber carbonization rate, which aim to solve the problem that in the prior art, accurate carbonization rate data cannot be output in real time due to the fact that the online measurement technology based on a voltammetry cannot effectively distinguish and strip the composite interference such as temperature fluctuation, current thermal effect and mechanical tension change on a production line. The technical scheme of the invention is as follows: An on-line detection device for carbon fiber carbonization rate comprises a box body, a guide wheel group, a multi-channel data acquisition device and a temperature acquisition assembly, wherein, One end of the box body is provided with a connecting flange for connecting an external carbonization furnace; the guide wheel set comprises a fiber grating guide wheel assembly and an electrode guide wheel assembly and is used for guiding and measuring running carbon fiber wires; the fiber bragg grating guide wheel assembly comprises two fiber bragg grating guide wheel assemblies which are arranged on the front side and the rear side of the box body along the running direction of the carbon fiber and are used for measuring the real-time tension of the carbon fiber; The electrode guide wheel assemblies comprise two electrode guide wheel assemblies, are arranged between the fiber bragg grating guide wheel assemblies and are positioned at the bottoms of the two fiber bragg grating guide wheel assemblies, and the two electrode guide wheel assemblies are electrically connected with an external current source and are used for applying constant measurement current to carbon fiber filaments; The multi-channel data acquisition device is arranged outside the box body, and the detection end of the multi-channel data acquisition device extends into the box body and is electrically connected with the two electrode guide wheel assemblies, and is used for applying current to the carbon fiber wires and leading out voltage measurement signals; the temperature acquisition assembly is arranged on a carbon fiber wire path between the two electrode guide wheel assemblies and is used for measuring a space temperature field of t