Two-way stretching device for PTFE (Polytetrafluoroethylene) filter membrane

Abstract

The utility model provides a two-way stretching device of a PTFE filter membrane, which comprises a workbench, the top of the workbench is fixedly connected with four moving frames, the top of each moving frame is provided with a moving groove, the inner wall of each moving groove is rotatably connected with a threaded rod, and the outer wall of each threaded rod is in threaded connection with a moving block. According to the utility model, the structures such as the moving frame, the variable-pitch frame, the driving assembly and the variable-pitch assembly are matched for use, so that synchronous stretching in four directions can be carried out through the electric clamping jaw, the uniform stress of the filter membrane in the stretching process can be ensured, and the stress concentration phenomenon possibly caused by traditional one-way or two-way stretching is avoided; according to the film stretching device, the risk that a film hole structure is not uniform or broken can be reduced, it is ensured that the film has better physical performance after being stretched, meanwhile, the stretching distance of the clamping jaws can be adjusted according to requirements through the equidistant and variable-pitch design of the variable-pitch assembly, balanced stress in the stretching process is ensured, and all areas of the film are stretched consistently.

Description

Technical Field

[0001] This utility model relates to the field of PTFE filter membrane technology, and in particular to a biaxial stretching device for PTFE filter membrane. Background Technology

[0002] Polytetrafluoroethylene (PTFE) is a high-performance material with excellent chemical stability, high temperature resistance, corrosion resistance, low coefficient of friction, and good electrical insulation. Due to these superior properties, PTFE membranes are widely used in filtration, diaphragm applications, electrical insulation, and gas separation, exhibiting unparalleled advantages, especially in applications requiring high temperature and highly corrosive environments. Biaxial stretching (BOP) technology was first applied to polyester films (such as BOPET membranes). Due to its excellent tensile properties and improved membrane characteristics, it has gradually been applied to other polymer materials, including PTFE. Biaxial stretching of PTFE membranes significantly increases the membrane's porosity, strength, and ductility, thereby improving its filtration efficiency and service life. However, due to the unique molecular structure of PTFE, the material has poor flexibility and loses its original structural stability at high temperatures. Therefore, the biaxial stretching process for PTFE membranes is more complex than that for other materials. During the stretching process, parameters such as heating temperature, stretching ratio, and stretching speed must be strictly controlled; otherwise, membrane rupture or uneven stretching can easily occur.

[0003] For example, Chinese utility model patent application number 202122241496.X discloses a biaxial stretching device for a PTFE filter membrane, which includes an operating table, a membrane body installed at the top of the operating table, a film winding component installed at the end of the membrane body, a transverse stretching mechanism installed at the bottom of the operating table, and a longitudinal stretching mechanism installed on the side of the operating table. The transverse stretching mechanism includes a first motor, with a transverse rotating shaft coaxially connected to its side. Several connecting shafts are connected to the side of the transverse rotating shaft, and transverse sleeve shafts are sleeved on the connecting shafts. The longitudinal stretching mechanism includes a second motor, with a longitudinal rotating shaft connected to its side. This utility model, through the configured transverse and longitudinal stretching mechanisms, allows the first motor to drive the transverse rotating shaft to rotate, simultaneously pushing and stretching the membrane body laterally while the transverse sleeve shafts rotate. The longitudinal stretching mechanism stretches the membrane body longitudinally, improving its stretching efficiency while ensuring its surface flatness.

[0004] While the above-mentioned method can stretch the filter membrane, the device divides the stretching into two stages: first horizontal stretching and then vertical stretching. Each stage requires independent adjustment and operation, which leads to a decrease in overall production efficiency. This is because stretching in each direction needs to be carried out independently and cannot be done simultaneously, thus prolonging the entire stretching process. At the same time, the two ends of the membrane may deform to different degrees due to the first horizontal stretching followed by the vertical stretching, which may cause uneven stretching of the membrane surface. Furthermore, the filter membrane needs to be heated and softened during the stretching process. If the temperature is insufficient, it may lead to uneven stretching or membrane breakage, while excessive temperature may cause material decomposition. Therefore, a bidirectional stretching device for PTFE filter membranes is proposed to solve the above problems. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defects of the existing technology. This utility model proposes a biaxial stretching device for PTFE filter membrane.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A workbench is included, with four movable frames fixedly connected to the top of the workbench. Each of the four movable frames has a movable groove on its top. A threaded rod is rotatably connected to the inner wall of the movable groove, and a movable block is threadedly connected to the outer wall of the threaded rod. A drive assembly capable of simultaneously driving the four movable blocks to move synchronously is provided on the workbench. A pitch-changing frame is fixedly connected to the inner top surface of each movable block. Two guide rods are fixedly connected to the inner wall of the pitch-changing frame. Several pitch-changing blocks are slidably connected to the outer walls of the two guide rods. An electric gripper is fixedly connected to one side of each pitch-changing block. A drive box is fixedly connected to one side of the pitch-changing frame. A pitch-changing assembly capable of driving several pitch-changing blocks to change pitch at equal intervals is provided on one side of the drive box. A support frame is fixedly connected to the top of the workbench. Two limiting rods slide through the top of the support frame, and a temperature component is provided at the bottom ends of the two limiting rods.

[0007] By setting up a drive component, servo motor one can drive the active bevel gear to drive four driven bevel gears, ensuring that the four sets of threaded rods rotate synchronously, so that the moving block moves at a constant speed along the moving groove, realizing four-way equal force stretching and eliminating the anisotropy of traditional bidirectional stretching. By setting up a pitch variable component, servo motor two can drive the pitch variable rod through a worm gear, using the differentiated trajectory of the pitch variable groove to control the pitch variable block to move at equal distances, dynamically adjusting the gripper spacing to adapt to different stretching ratio requirements. By setting up a temperature component, the height of the heating plate can be adjusted through the drive plate, quickly responding to temperature changes and avoiding the problems of local overheating or uneven cooling caused by traditional fixed heating. It can also automatically adjust to adapt to the needs of different types and thicknesses of filter membranes.

[0008] As a further description of the above technical solution:

[0009] The drive assembly includes a servo motor fixedly installed at the bottom of the workbench. The output end of the servo motor rotates through to the outside of the workbench and is fixedly connected to a rotating shaft. An active bevel gear is fixedly connected to the outer wall of the rotating shaft, and a protective frame is rotatably connected to the top of the rotating shaft.

[0010] The bottom of the protective frame is fixedly connected to the top of the working strip.

[0011] As a further description of the above technical solution:

[0012] The outer wall of the driving bevel gear is meshed with four driven bevel gears, and each of the four driven bevel gears has a driven shaft fixedly connected inside.

[0013] One end of the driven shaft rotates through the interior of the movable frame and is fixedly connected to the threaded rod.

[0014] As a further description of the above technical solution:

[0015] The pitch control assembly includes a second servo motor fixedly mounted on one side of the drive housing. The output end of the second servo motor rotates through the interior of the drive housing and is fixedly connected to a worm gear.

[0016] One end of the worm gear is rotatably connected to the inner wall of the drive box.

[0017] As a further description of the above technical solution:

[0018] The outer wall of the worm gear is meshed with a worm wheel, and the inside of the worm wheel is fixedly connected to a connecting shaft. One end of the connecting shaft rotatably passes through the inside of the pitch frame and is fixedly connected to a pitch rod.

[0019] The other end of the connecting shaft is rotatably connected to the inner wall of the drive box, and one end of the pitch rod is rotatably connected to the inner wall of the pitch frame.

[0020] As a further description of the above technical solution:

[0021] The outer wall of the pitch rod is provided with several pitch grooves, and a limiting post is slidably connected inside the pitch groove.

[0022] The bottom end of the limiting column is fixedly connected to the pitch block.

[0023] As a further description of the above technical solution:

[0024] The temperature assembly includes a heating plate that is fixedly installed at the bottom of two guide rods. Several heating wires are fixedly installed inside the heating plate. A lifting screw is rotatably connected to the top of the heating plate. A drive disk is fixedly connected to the top of the lifting screw. The outer wall of the lifting screw is threadedly connected to the support frame.

[0025] By adjusting the distance between the heating wire and the filter membrane, staff can adjust the heating temperature in real time to ensure the accuracy of the heating process.

[0026] As a further description of the above technical solution:

[0027] A controller is fixedly installed on the top of the workbench.

[0028] The outer wall of the movable block slides along the movable groove. By setting a controller, the device can be easily controlled by the staff, thus making it easy to use.

[0029] 1. Compared with the prior art, the beneficial effects of this utility model include: by using the combined structure of the moving frame, the variable-pitch frame, the drive assembly, and the variable-pitch assembly, the membrane can be stretched synchronously in four directions by the electric gripper. This ensures that the filter membrane is subjected to uniform force during the stretching process, avoiding stress concentration that may be caused by traditional unidirectional or bidirectional stretching. It can reduce the risk of uneven membrane pore structure or breakage, and ensure that the membrane material has better physical properties after stretching. At the same time, through the equidistant variable-pitch design of the variable-pitch assembly, the stretching distance of the gripper can be adjusted according to the needs, ensuring balanced force during the stretching process, making the stretching of each area of ​​the membrane material consistent, further optimizing the physical properties of the membrane material. Moreover, compared with the traditional bidirectional stretching method, this design can complete the membrane stretching process in one go, reducing production steps and improving work efficiency.

[0030] 2. Compared with the prior art, the beneficial effects of this utility model include: by using the support frame, limiting rod, temperature component and controller in combination, the distance between the heating wire and the filter membrane can be precisely controlled, thereby effectively adjusting the heating temperature. By ensuring uniform heating of the membrane material, the tensile and extensibility of the membrane are improved, providing good physical conditions for subsequent stretching, reducing the risk of cracks or defects during stretching, and allowing operators to adjust the heating temperature in real time, providing more adaptability for stretching different types of membrane materials and ensuring that the membrane material reaches the optimal stretching state. Attached Figure Description

[0031] The disclosure of this utility model is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0032] Figure 1 The schematic diagram shows a three-dimensional view of the overall structure of a biaxial stretching device for a PTFE filter membrane according to one embodiment of the present invention.

[0033] Figure 2The schematic diagram shows another perspective view of the overall structure of a biaxial stretching device for a PTFE filter membrane according to one embodiment of the present invention.

[0034] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0035] Figure 4 The schematic diagram shows a three-dimensional view of the drive assembly structure of a biaxial stretching device for a PTFE filter membrane according to one embodiment of the present invention.

[0036] Figure 5 The diagram schematically shows a three-dimensional view of an equidistant component structure of a biaxial stretching device for a PTFE filter membrane according to one embodiment of the present invention.

[0037] The diagram labels are as follows: 1. Worktable; 2. Moving frame; 3. Moving groove; 4. Threaded rod; 5. Moving block; 6. Pitch-changing frame; 7. Guide rod; 8. Pitch-changing block; 9. Electric gripper; 10. Drive box; 11. Support frame; 12. Limiting rod; 13. Servo motor one; 14. Rotating shaft; 15. Driving bevel gear; 16. Protective frame; 17. Driven bevel gear; 18. Driven shaft; 19. Servo motor two; 20. Worm gear; 21. Worm wheel; 22. Connecting shaft; 23. Pitch-changing rod; 24. Pitch-changing groove; 25. Limiting column; 26. Heating plate; 27. Heating wire; 28. Lifting screw; 29. ​​Drive disc; 30. Controller. Detailed Implementation

[0038] It is readily understood that, based on the technical solution of this utility model, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this utility model. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative descriptions of the technical solution of this utility model and should not be considered as the entirety of this utility model or as limitations or restrictions on the technical solution of this utility model.

[0039] According to one embodiment of the present invention, in conjunction with Figure 1-5As shown. A biaxial stretching device for a PTFE filter membrane includes a worktable 1. Four movable frames 2 are fixedly connected to the top of the worktable 1. Each of the four movable frames 2 has a movable groove 3 on its top. A threaded rod 4 is rotatably connected to the inner wall of the movable groove 3. A movable block 5 is threadedly connected to the outer wall of the threaded rod 4. A drive assembly capable of simultaneously driving the four movable blocks 5 to move synchronously is provided on the worktable 1. A pitch-changing frame 6 is fixedly connected to the inner top surface of the movable block 5. Two guide rods 7 are fixedly connected to the inner wall of the pitch-changing frame 6. Several pitch-changing blocks 8 are slidably connected to the outer walls of the two guide rods 7. An electric gripper 9 is fixedly connected to one side of each pitch-changing block 8. A drive box 10 is fixedly connected to one side of the variable pitch frame 6. A variable pitch assembly capable of driving several variable pitch blocks 8 to change pitch at equal intervals is set on one side of the drive box 10. A support frame 11 is fixedly connected to the top of the worktable 1. Two limiting rods 12 slide through the top of the support frame 11. A temperature component is set at the bottom of the two limiting rods 12. By setting the drive assembly, the servo motor 13 can drive the active bevel gear 15 to drive four driven bevel gears 17, ensuring that the four sets of threaded rods 4 rotate synchronously, so that the moving block 5 moves at a constant speed along the moving groove 3, realizing four-way equal force tension, eliminating the anisotropy of traditional bidirectional tension, and by setting the variable pitch assembly... The system utilizes a servo motor 219 to drive a variable-pitch rod 23 via a worm gear 21 and a worm 20. The variable-pitch block 8 is moved at equal intervals using the differentiated trajectory of the variable-pitch groove 24, dynamically adjusting the gripper spacing to adapt to different stretching ratios. A temperature component allows for adjustment of the heating plate 26 height via a drive disc 29, quickly responding to temperature changes and avoiding localized overheating or uneven cooling problems caused by traditional fixed heating. It also automatically adjusts to meet the needs of different types and thicknesses of filter membranes. Through the coordinated use of the moving frame 2, variable-pitch frame 6, drive component, and variable-pitch component, the electric gripper 9 can move the variable-pitch rod 23. Simultaneous stretching in four directions ensures uniform stress on the filter membrane during stretching, avoiding stress concentration that may occur with traditional unidirectional or bidirectional stretching. This reduces the risk of uneven membrane pore structure or breakage, ensuring better physical properties of the membrane material after stretching. Furthermore, the equidistant variable-pitch design of the variable-pitch assembly allows adjustment of the gripper's stretching distance as needed, ensuring balanced stress during stretching and consistent stretching across all areas of the membrane material. This further optimizes the membrane's physical properties. Compared to traditional bidirectional stretching methods, this design completes the membrane stretching process in one step, reducing production steps and improving work efficiency.

[0040] The drive assembly includes a servo motor 13 fixedly mounted on the bottom of the worktable 1. The output end of the servo motor 13 rotatably extends to the outside of the worktable 1 and is fixedly connected to a rotating shaft 14. A drive bevel gear 15 is fixedly connected to the outer wall of the rotating shaft 14. A protective frame 16 is rotatably connected to the top of the rotating shaft 14. The bottom of the protective frame 16 is fixedly connected to the top of the work bar. Four driven bevel gears 17 are meshed with the outer wall of the drive bevel gear 15. A driven shaft 18 is fixedly connected inside each of the four driven bevel gears 17. One end of the driven shaft 18 rotatably extends into the interior of the moving frame 2 and is fixedly connected to the threaded rod 4.

[0041] The pitch-changing assembly includes a second servo motor 19 fixedly installed on one side of the drive housing 10. The output end of the second servo motor 19 rotatably penetrates into the interior of the drive housing 10 and is fixedly connected to a worm gear 20. One end of the worm gear 20 is rotatably connected to the inner wall of the drive housing 10. A worm wheel 21 is meshed with the outer wall of the worm gear 20. A connecting shaft 22 is fixedly connected inside the worm wheel 21. One end of the connecting shaft 22 rotatably penetrates into the interior of the pitch-changing frame 6 and is fixedly connected to a pitch-changing rod 23. The other end of the connecting shaft 22 is rotatably connected to the inner wall of the drive housing 10. One end of the pitch-changing rod 23 is rotatably connected to the inner wall of the pitch-changing frame 6. Several pitch-changing grooves 24 are opened on the outer wall of the pitch-changing rod 23. A limiting post 25 is slidably connected inside the pitch-changing groove 24. The bottom end of the limiting post 25 is fixedly connected to the pitch-changing block 8.

[0042] The temperature assembly includes a heating plate 26 fixedly mounted at the bottom of two guide rods 7. Several heating wires 27 are fixedly installed inside the heating plate 26. A lifting screw 28 is rotatably connected to the top of the heating plate 26. A drive disk 29 is fixedly connected to the top of the lifting screw 28. The outer wall of the lifting screw 28 is threadedly connected to the support frame 11. By adjusting the distance between the heating wires 27 and the filter membrane, the operator can adjust the heating temperature in real time to ensure the accuracy of the heating process. A controller 30 is fixedly installed on the top of the workbench 1. The outer wall of the moving block 5 slides along the moving groove 3. By setting the controller 30, the operator can easily control the device, thus facilitating its use.

[0043] The working principle of this embodiment is as follows: First, the controller 30 is electrically connected to the electric gripper 9, servo motor 13, and servo motor 29 to the heating wire 27 for easier control of the device. Then, the filter membrane to be stretched can be placed in the middle of the device. The electric gripper 9 is then activated to clamp the edges of the filter membrane to prevent it from easily falling off during the subsequent stretching process. The heating wire 27 can then be controlled to generate heat. The bottom of the heating plate has a heating groove, which allows the heat generated by the heating wire 27 to heat and bake the filter membrane more quickly, ensuring heating efficiency. When the heating temperature is high or low, the operator can rotate the drive plate 29. The rotation of the drive plate 29 drives the lifting screw 28 to rotate, thereby causing the heating plate 26 to rise and fall along the guide rod 7, which in turn causes the heating wire 27 to rise or fall. The temperature can be adjusted by adjusting the distance between the heating wire 27 and the filter membrane, allowing the operator to automatically adjust the appropriate heating temperature. At the same time, the heated membrane has better tensile and extensibility, can be stretched evenly, reduces local stress concentration, and avoids cracks or defects in the membrane during the stretching process.

[0044] Once heated, servo motor 13 and servo motor 19 can be simultaneously started via controller 30. The output of servo motor 13 rotates, causing the rotating shaft 14 to rotate, which in turn rotates the driving bevel gear 15, thereby driving the four driven bevel gears 17 to rotate. Simultaneously, the driven shaft 18 rotates, causing the four threaded rods 4 to rotate as well. This allows the moving block 5 to move along the opening moving groove 3, thereby causing the electric grippers 9 on the variable pitch frame 6 to stretch the filter membrane in four directions. At the same time, the start of servo motor 19 also drives the worm gear 20 to rotate, and the rotation of the worm gear 20 synchronously drives the meshing worm... The rotation of wheel 21 synchronously drives the connecting shaft 22 to rotate, causing the pitch rod 23 to rotate synchronously as well. This causes the limiting post 25 on the pitch block 8 to move along the pitch groove 24. Because the pitch grooves 24 are different, the pitch block 8 moves at equal intervals. Thus, during the synchronous stretching process, the pitch assembly allows the grippers to stretch synchronously, forming a multi-directional balanced force. Compared with traditional unidirectional or bidirectional stretching, it can more effectively avoid the risk of uneven membrane pore structure or breakage caused by local stress concentration. At the same time, it can complete the membrane stretching in one go. Compared with traditional bidirectional stretching, it can complete the stretching process faster, which helps to improve production efficiency.

[0045] The technical scope of this utility model is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this utility model, and all such modifications and variations should fall within the protection scope of this utility model.

Claims

1. A biaxial stretching device for a PTFE filter membrane, comprising a worktable (1), characterized in that; Four movable frames (2) are fixedly connected to the top of the workbench (1). Each of the four movable frames (2) has a movable slot (3) on its top. A threaded rod (4) is rotatably connected to the inner wall of the movable slot (3). A movable block (5) is threadedly connected to the outer wall of the threaded rod (4). A drive assembly capable of simultaneously driving the four movable blocks (5) to move synchronously is provided on the workbench (1). A variable pitch frame (6) is fixedly connected to the inner top surface of each movable block (5). Two guide rods (7) are fixedly connected to the inner wall of the variable pitch frame (6). The outer wall of the rod (7) is slidably connected to several pitch blocks (8). An electric gripper (9) is fixedly connected to one side of the pitch block (8). A drive box (10) is fixedly connected to one side of the pitch frame (6). A pitch component capable of driving several pitch blocks (8) to change pitch at equal intervals is provided on one side of the drive box (10). A support frame (11) is fixedly connected to the top of the workbench (1). Two limiting rods (12) slide through the top of the support frame (11). A temperature component is provided at the bottom of the two limiting rods (12).

2. The biaxial stretching device for a PTFE filter membrane according to claim 1, characterized in that, The drive assembly includes a servo motor (13) fixedly installed at the bottom of the workbench (1). The output end of the servo motor (13) rotates through to the outside of the workbench (1) and is fixedly connected to a rotating shaft (14). An active bevel gear (15) is fixedly connected to the outer wall of the rotating shaft (14). A protective frame (16) is rotatably connected to the top of the rotating shaft (14).

3. The biaxial stretching device for a PTFE filter membrane according to claim 2, characterized in that, The outer wall of the driving bevel gear (15) is meshed with four driven bevel gears (17), and each of the four driven bevel gears (17) is fixedly connected to a driven shaft (18).

4. The biaxial stretching device for a PTFE filter membrane according to claim 1, characterized in that, The pitch-changing assembly includes a second servo motor (19) fixedly installed on one side of the drive housing (10). The output end of the second servo motor (19) rotates through the interior of the drive housing (10) and is fixedly connected to a worm gear (20).

5. The biaxial stretching device for a PTFE filter membrane according to claim 4, characterized in that, The outer wall of the worm (20) is meshed with a worm wheel (21), and a connecting shaft (22) is fixedly connected inside the worm wheel (21). One end of the connecting shaft (22) rotates through the interior of the pitch frame (6) and is fixedly connected to a pitch rod (23).

6. The biaxial stretching device for a PTFE filter membrane according to claim 5, characterized in that, The outer wall of the variable pitch rod (23) is provided with a plurality of variable pitch grooves (24), and a limiting post (25) is slidably connected inside the variable pitch groove (24).

7. The biaxial stretching device for a PTFE filter membrane according to claim 1, characterized in that, The temperature assembly includes a heating plate (26) that is fixedly installed at the bottom of two guide rods (7). Several heating wires (27) are fixedly installed inside the heating plate (26). A lifting screw (28) is rotatably connected to the top of the heating plate (26). A drive disk (29) is fixedly connected to the top of the lifting screw (28). The outer wall of the lifting screw (28) is threadedly connected to the support frame (11).

8. The biaxial stretching device for a PTFE filter membrane according to claim 1, characterized in that, A controller (30) is fixedly installed on the top of the workbench (1).

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