Filtration system for dry polyacrylonitrile-based stock solution

Abstract

This utility model discloses a filtration system for dry-process polyacrylonitrile-based raw materials, belonging to the field of spinning technology. The technical solution is as follows: The filtration system for dry-process polyacrylonitrile-based raw materials includes a main feed pipeline and a controller; the main feed pipeline is connected to a filter 1 via a branch pipeline 1, which is equipped with a gear metering pump 1; the outlet of the gear metering pump 1 is connected to the filter 1, and the gear metering pump 1 is electrically connected to the controller; the outlet of the filter 1 is connected to a filter 2 via a branch pipeline 2, which is equipped with a pressure sensor 1 and a gear metering pump 2; the outlet of the gear metering pump 2 is connected to the filter 2, and both the pressure sensor 1 and the gear metering pump 2 are electrically connected to the controller; the outlet of the filter 2 is connected to a filter 3 via a branch pipeline 3, which is equipped with a pressure sensor 2 and a gear metering pump 3. This utility model reduces filter pressure differential, minimizes gel penetration, and improves filtration accuracy through multi-stage filtration.

Description

Technical Field

[0001] This utility model belongs to the field of spinning technology, specifically relating to a filtration system for dry polyacrylonitrile-based raw materials. Background Technology

[0002] Carbon fiber, due to its high strength, high modulus, high temperature resistance, and lightweight properties, is widely used in aerospace, new energy vehicles, wind turbine blades, and sporting goods. As the core raw material for carbon fiber production, the purity and uniformity of the polyacrylonitrile (PAN)-based dosing directly determine the final carbon fiber performance. However, PAN-based dosing often contains unreacted monomers, catalyst residues, gel particles, and mechanical impurities during production. These defects can lead to problems such as fiber breakage and fuzzing during subsequent spinning, severely affecting the mechanical properties and surface quality of the carbon fiber. Therefore, controlling the purity of the dosing is crucial. Traditional filtration systems often employ single-stage filtration structures, resulting in low filtration efficiency and insufficient precision. They rely heavily on a single pump to control flow, making it difficult to precisely adjust the pressure at each stage. Pressure fluctuations during dosing treatment can easily cause filter element clogging, leading to inconsistent purity. Furthermore, frequent filter element replacement results in high maintenance costs and long downtime. In addition, filter element structures are often designed for single use, preventing reuse and increasing production costs. Therefore, a highly efficient, controllable, and easy-to-maintain multi-stage filtration system is urgently needed to improve dosing quality and production efficiency. Utility Model Content

[0003] This invention provides a filtration system for dry polyacrylonitrile-based stock solution, which reduces filter pressure difference, minimizes gel penetration, and improves filtration accuracy through multi-stage filtration.

[0004] The technical solution of this utility model is as follows:

[0005] A filtration system for dry-process polyacrylonitrile-based raw materials includes a main feed line and a controller. The main feed line connects to a filter (Filter 1) via a branch line, which is equipped with a gear metering pump (GMP). The outlet of GMP is connected to Filter 1 and is electrically connected to the controller. The outlet of Filter 1 connects to Filter 2 via a branch line, which is equipped with a pressure sensor (Pressure Sensor 1) and GMP. The outlet of GMP is connected to Filter 2, and both the pressure sensor and GMP are electrically connected to the controller. The outlet of Filter 2 connects to Filter 3 via a branch line, which is equipped with a pressure sensor (Pressure Sensor 2) and GMP. The outlet of GMP is connected to Filter 3, and both the pressure sensor and GMP are electrically connected to the controller. The outlet of Filter 3 connects to a branch line, which is equipped with a pressure sensor (Pressure Sensor 3) and GMP. Both the pressure sensor and GMP are electrically connected to the controller. The outlet of GMP is connected to a spinning line.

[0006] Preferably, filters one, two, and three each include a filter housing, with a jacket provided outside the filter housing. The jacket has a jacket medium inlet and a jacket medium outlet. A removable cover is provided on the top of the filter housing, with a pressure relief valve and a discharge port on the top of the cover. The pressure relief valve is electrically connected to the controller. A feed inlet is provided at the bottom of the filter housing. A central tube is provided in the middle of the filter housing, passing through the cover and connecting to the discharge port. The central tube has multiple guide holes. Multiple filter discs are installed in series at equal intervals along the axial direction with the central tube as the axis. The top and bottom filter discs are fixedly connected to the central tube to ensure that the entire filter disc assembly works stably and reliably within the filter, achieving a high-efficiency filtration function. The filter discs include an upper cover and a lower cover. A support frame is provided between the upper and lower covers. Filter layer one is located on the upper part of the support frame, and filter layer two is located on the lower part. Grooves are formed on the lower surface of the upper cover and the upper surface of the lower cover, respectively. These grooves provide space for the support frame, filter layer one, and filter layer two. The support frame, filter layer one, and filter layer two are placed between the upper and lower covers and secured with screws. The support frame has a circular disc structure with a mounting hole in its center that matches the outer diameter of the central tube. It is tightly fitted onto the central tube through this mounting hole, connecting the filter disc to the central tube. The support frame is made of a high-strength, corrosion-resistant metal material, such as stainless steel, possessing good mechanical strength to support the entire filter disc structure and prevent deformation due to material pressure during filtration. Filter layer one and filter layer two each include a guide plate and filter discs from top to bottom. The guide plate has several guide spirals forming a guide slope.

[0007] Preferably, the filter housing and cover are connected by a flange.

[0008] Preferably, the guide plate has a guide slope angle of 30°-45°, and the filter is a metal fiber felt.

[0009] Preferably, it also includes a sealing gasket disposed between two adjacent filter discs; the sealing gasket is made of a material with good elasticity and corrosion resistance, such as rubber or silicone. When multiple filter discs are stacked and installed on the central tube, the sealing gasket undergoes elastic deformation under the compression of adjacent filter discs, thereby forming a good sealing effect, preventing material leakage between filter discs, and ensuring that material can only be filtered through the filter layer.

[0010] Preferably, the edges of both filter layer one and filter layer two are fixed to the support frame by bolts. The bolts fix the edges of the filter layers and, together with the sealing gaskets, prevent leakage and enhance the structural strength, thus meeting the long-term operation requirements of high-viscosity fluids.

[0011] Compared with the prior art, this utility model has the following advantages:

[0012] 1. This utility model features multi-stage filtration, which gradually improves filtration accuracy and removes impurities and gels from the dry PAN stock solution in multiple stages, thereby improving filtration accuracy. At the same time, the pressure requirements of the filter are reduced, and the manufacturing cost is lowered.

[0013] 2. The filter disc adopts a double-layer metal fiber felt and a flow-guiding inclined surface design (tilt angle 30°-45°) to increase the filtration area, guide the fluid to diffuse outward, reduce pressure difference, and improve filtration accuracy and efficiency.

[0014] 3. The jacket structure allows for the introduction of a constant-temperature medium to maintain the stability of the original liquid viscosity and prevent temperature fluctuations from affecting the filtration effect.

[0015] 4. The removable cover and flange connection design simplifies the filter replacement process; the pressure relief valve is linked with the controller to automatically handle abnormal high pressure and reduce downtime. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the filtration system structure of the dry-process polyacrylonitrile-based raw liquid of this utility model.

[0017] Figure 2 This is a structural schematic diagram of filter one, filter two and filter three of this utility model.

[0018] Figure 3 This is a schematic diagram of the structure of the filter disc of this utility model.

[0019] Figure 4 This is a schematic diagram of the structure of the guide plate of this utility model.

[0020] In the diagram: 1. Main feed line for raw liquid; 2. Branch line 1 for raw liquid; 3. Filter 1; 4. Gear metering pump 1; 5. Branch line 2 for raw liquid; 6. Filter 2; 7. Pressure sensor 1; 8. Gear metering pump 2; 9. Branch line 3 for raw liquid; 10. Filter 3; 11. Pressure sensor 2; 12. Gear metering pump 3; 13. Branch line 4 for raw liquid; 14. Pressure sensor 3; 15. Gear metering pump 4; 16. Spinning line; 17. Filter housing; 18. Jacket; 19. Jacket medium inlet; 20. Jacket medium outlet; 21. Cover plate; 22. Pressure relief valve; 23. Discharge port; 24. Inlet; 25. Central tube; 26. Guide hole; 27. Filter disc; 28. Upper cover; 29. ​​Lower cover; 30. Support frame; 31. Filter layer 1; 32. Filter layer 2; 33. Guide plate; 34. Guide spiral. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model.

[0022] Example 1

[0023] like Figures 1-4 As shown, this embodiment provides a filtration system for dry polyacrylonitrile-based raw material, including a main feed pipeline 1 and a controller;

[0024] The main feed line 1 of the raw liquid is connected to the filter 3 through the raw liquid branch line 2. The raw liquid branch line 2 is equipped with a gear metering pump 4. The outlet of the gear metering pump 4 is connected to the filter 3. The gear metering pump 4 is electrically connected to the controller.

[0025] The outlet of filter 13 is connected to filter 26 via raw liquid branch 25. The raw liquid branch 25 is equipped with pressure sensor 17 and gear metering pump 28. The outlet of gear metering pump 28 is connected to filter 26. Both pressure sensor 17 and gear metering pump 28 are electrically connected to the controller.

[0026] The outlet of filter 26 is connected to filter 310 via raw liquid branch 39. The raw liquid branch 39 is equipped with pressure sensor 211 and gear metering pump 312. The outlet of gear metering pump 312 is connected to filter 310. Pressure sensor 211 and gear metering pump 312 are both electrically connected to the controller.

[0027] The outlet of filter 310 is connected to raw liquid branch 413, which is equipped with pressure sensor 314 and gear metering pump 415. Both pressure sensor 314 and gear metering pump 415 are electrically connected to the controller. The outlet of gear metering pump 415 is connected to spinning pipeline 16.

[0028] Filter 1 (3), Filter 2 (6), and Filter 3 (10) all include a filter housing 17. A jacket 18 is provided outside the filter housing 17, with a jacket medium inlet 19 and a jacket medium outlet 20. A detachable cover plate 21 is provided on the top of the filter housing 17, and the filter housing 17 and the cover plate 21 are connected by a flange. A pressure relief valve 22 and a discharge port 23 are provided on the top of the cover plate 21. The pressure relief valve 22 is electrically connected to a controller. A feed inlet 24 is provided at the bottom of the filter housing 17. A central tube 25 is provided in the middle of the filter housing 17, passing through the cover plate 21 and connecting to the discharge port 23. The central tube 25 has multiple guide holes 26. Multiple layers of filter discs 27 are installed in series at equal intervals along the axial direction with the central tube 25 as the axis. The topmost and bottommost filter discs 27 are fixedly connected to the central tube 25, ensuring that the entire filter disc 27 assembly works stably and reliably within the filter, achieving a highly efficient filtration function.

[0029] The filter disc 27 includes an upper cover 28 and a lower cover 29. A support frame 30 is provided between the upper cover 28 and the lower cover 29. The support frame 30 has a circular disc structure and a mounting hole in its center that matches the outer diameter of the central tube 25. The filter disc 27 is tightly fitted onto the central tube 25 through the mounting hole, thereby connecting the filter disc 27 to the central tube 25. A first filter layer 31 is provided on the upper part of the support frame 30, and a second filter layer 32 is provided on the lower part of the support frame 30. Grooves are provided on the lower surface of the upper cover 28 and the upper surface of the lower cover 29, respectively. The grooves provide space for the support frame 30, the first filter layer 31, and the second filter layer 32. The support frame 30, the first filter layer 31, and the second filter layer 32 are placed between the upper cover 28 and the lower cover 29 and fixed with screws.

[0030] Both filter layer 31 and filter layer 32 include a guide plate 33 and filter discs from top to bottom. The guide plate 33 is provided with several guide spirals 34, which form a guide slope. The guide slope of the guide plate 33 has an inclination angle of 30°. It also includes a sealing gasket disposed between two adjacent filter discs 27. The sealing gasket is made of rubber material. The edges of filter layer 31 and filter layer 32 are fixed to the support frame 30 by bolts. The bolts fix the edges of the filter layers, and together with the sealing gaskets, prevent leakage and enhance structural strength, adapting to the long-term operation requirements of high-viscosity fluids.

[0031] Work process:

[0032] The raw liquid, with a pressure of 1.9 MPa, enters the raw liquid branch 2 through the main raw liquid feed line 1, and then enters the filter 3 through the gear metering pump 4. The controller dynamically adjusts the pump speed according to the pressure sensor data to ensure that the pressure is stable at 1.9 MPa. The raw liquid enters from the bottom feed port 24, is dispersed into the multi-layer filter discs 27 through the guide holes 26, and the guide slope makes the fluid diffuse evenly. It flows through the flow channels set on the outer edge of the filter discs 27 to the central pipe 25. The metal fiber felt intercepts impurities step by step, and after filtration, it enters the raw liquid branch 5.

[0033] Gear metering pump 28 and pressure sensor 17 work together to control the flow and pressure of raw liquid branch 25. The raw liquid enters filter 26 for further filtration; similarly, it enters filter 30 via raw liquid branch 39 for final fine filtration. Jacket 18 maintains a constant temperature through media circulation to prevent changes in the viscosity of the raw liquid. After filtration, it is delivered to spinning pipeline 16 via raw liquid branch 43.

[0034] If a pressure sensor detects overpressure, the controller triggers the corresponding pressure relief valve 22 to release pressure or adjust the pump speed, while simultaneously prompting for maintenance. After a period of operation, the screws around the filter disc 27 are removed, and the filter disc 27 is disassembled. After cleaning the upper cover 28, lower cover 29, and support frame 30, the guide plate 33 and filter disc are cleaned by acid washing, ultrasonic cleaning, etc. Then, the cleaned upper guide plate 33, filter disc, and support frame 30 are placed between the upper cover 28 and lower cover 29 according to their relative positions and fixed with the screws around the perimeter. Finally, the filter disc 27 is placed into the filter for further filtration of the spinning solution.

Claims

1. A filtration system for dry-process polyacrylonitrile-based stock solution, characterized in that, Includes the main feed line (1) for the raw liquid and a controller; The main feed line (1) of the raw liquid is connected to the filter (3) through the raw liquid branch (2). The raw liquid branch (2) is equipped with a gear metering pump (4). The outlet of the gear metering pump (4) is connected to the filter (3). The gear metering pump (4) is electrically connected to the controller. The outlet of filter one (3) is connected to filter two (6) through raw liquid branch two (5). The raw liquid branch two (5) is equipped with pressure sensor one (7) and gear metering pump two (8). The outlet of gear metering pump two (8) is connected to filter two (6). Pressure sensor one (7) and gear metering pump two (8) are both electrically connected to the controller. The outlet of filter 2 (6) is connected to filter 3 (10) through raw liquid branch 3 (9). The raw liquid branch 3 (9) is equipped with pressure sensor 2 (11) and gear metering pump 3 (12). The outlet of gear metering pump 3 (12) is connected to filter 3 (10). Pressure sensor 2 (11) and gear metering pump 3 (12) are both electrically connected to the controller. The outlet of filter three (10) is connected to raw liquid branch four (13), and raw liquid branch four (13) is equipped with pressure sensor three (14) and gear metering pump four (15); pressure sensor three (14) and gear metering pump four (15) are both electrically connected to the controller; the outlet of gear metering pump four (15) is connected to the spinning pipeline (16).

2. The filtration system for dry-process polyacrylonitrile-based precursor solution according to claim 1, wherein The filter one (3), filter two (6) and filter three (10) all include a filter housing (17), a jacket (18) is provided outside the filter housing (17), the jacket (18) is provided with a jacket medium inlet (19) and a jacket medium outlet (20), a detachable cover plate (21) is provided on the top of the filter housing (17), a pressure relief valve (22) and a discharge port (23) are provided on the top of the cover plate (21), the pressure relief valve (22) and the controller are electrically connected; a feed inlet (24) is provided at the bottom of the filter housing (17); a central tube (25) is provided in the middle of the filter housing (17), the central tube (25) passes through the cover plate (21) and is connected to the discharge port (23), the central tube (25) is provided with multiple guide holes (26), and multiple layers of filter discs (27) are installed in series at equal intervals along the axial direction with the central tube (25) as the axis; The filter disc (27) includes an upper cover (28) and a lower cover (29). A support frame (30) is provided between the upper cover (28) and the lower cover (29). A filter layer (31) is provided on the upper part of the support frame (30), and a filter layer (32) is provided on the lower part of the support frame (30). Grooves are provided on the lower surface of the upper cover (28) and the upper surface of the lower cover (29). The grooves are used to provide space for the support frame (30), the filter layer (31) and the filter layer (32). The support frame (30), the filter layer (31) and the filter layer (32) are placed between the upper cover (28) and the lower cover (29) and fixed with screws. The support frame (30) has a circular disc structure, and its center is provided with an installation hole that matches the outer diameter of the central tube (25). It is tightly fitted onto the central tube (25) through the installation hole to realize the connection between the filter disc (27) and the central tube (25). Both filter layer one (31) and filter layer two (32) include a guide plate (33) and a filter sheet from top to bottom. The guide plate (33) is provided with several guide spirals (34), and the guide spirals (34) form a guide slope.

3. The filtration system for dry-process polyacrylonitrile-based precursor solution according to claim 2, wherein The filter housing (17) and cover plate (21) are connected by a flange.

4. The filtration system for dry-process polyacrylonitrile-based precursor solution according to claim 2, wherein The guide plate (33) has a guide slope angle of 30°-45°, and the filter is a metal fiber felt.

5. The filtration system for dry-process polyacrylonitrile-based precursor solution according to claim 2, wherein It also includes a sealing gasket disposed between two adjacent filter discs (27).

6. The filtration system for dry-process polyacrylonitrile-based precursor solution according to claim 2, wherein The edges of both filter layer one (31) and filter layer two (32) are fixed to the support frame (30) by bolts.

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