A method for producing a ptf filter fabric

Abstract

This invention discloses a method for producing PTFE filter fabric. It involves feeding PVC-U and PTFE filaments without drafting onto a ring spinning machine equipped with a yarn guiding device including a mounting frame, an arc-shaped connecting piece, and a spiral yarn guide hook. This allows for positional adjustment of the yarn guide hook and yarn tube during operation, maintaining concentricity and achieving efficient plying. High-temperature setting removes PVC-U, effectively preserving the crimp formed by the twisting of the PTFE filaments, resulting in PTFE twisted filaments with improved cohesion. By using PTFE, PPS, and aramid filaments as core yarns and the other two as outer layers, three types of PTFE composite yarns are produced. The PTFE twisted filaments are used as weft yarns, and the three types of PTFE composite yarns combined with the PTFE twisted filaments are used as warp yarns, achieving the processing of a PTFE filter fabric with both excellent strength and breathability.

Description

Technical Field

[0001] This invention relates to the field of new textile technology, and in particular to a method for producing PTFE filter fabric. Background Technology

[0002] Polytetrafluoroethylene (PTFE) filament production uses PTFE dispersion resin as raw material. This is achieved through mixing with a liquid lubricant (such as kerosene), followed by extrusion, calendering, stretching, cutting, sintering, and final cooling to form continuous filaments. In PTFE, the fluorine atoms connecting the carbon chains on both sides have larger radii than hydrogen atoms, and fluorine atoms almost completely cover the surface of the carbon chains. Combined with the helical, twisted chain structure formed by adjacent macromolecular chains, PTFE materials possess excellent high and low temperature resistance, excellent corrosion resistance, excellent weather resistance, excellent lubrication properties, and excellent electrical insulation properties. Due to its superior properties, PTFE materials are widely used in important fields such as national defense, petroleum, radio, power machinery, environmental protection, and the chemical industry.

[0003] PTFE fabrics should be free of oil and impurities, with minimal slippage between yarns. Filter materials in environmental protection equipment require both excellent high-temperature resistance and acid / alkali resistance, especially for separating and filtering dust and other substances under strong acid and alkali conditions. Ordinary filter media cannot meet the stringent environmental requirements. PTFE fibers, with their excellent high-temperature and acid / alkali resistance, are the preferred choice for filter materials. However, these fibers have low cohesion and a low coefficient of friction, which affects the weaving and mechanical properties of the fabric. Therefore, in practical applications, solutions include either directly improving the cohesion of PTFE filaments and enhancing the material's processing performance, such as by twisting the PTFE filaments; or using blending or composite methods to compensate for these shortcomings, combining PTFE with other high-performance fibers to create nonwoven or woven fabrics, achieving a balance between performance and cost. The key lies in achieving efficient twisting of PTFE filaments, effectively retaining the crimp formed by the twist, and organically combining them with other high-performance fibers. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing PTFE filter fabric. This method involves feeding vinylon filament and PTFE filament onto a ring spinning machine without drafting. The machine is equipped with a yarn guide hook device including a mounting frame, an arc-shaped connecting piece, and a spiral yarn guide hook, achieving efficient plying of the two. After high-temperature setting, the vinylon filament is removed, effectively preserving the crimp formed by the twisting of the PTFE filament ply, thus producing PTFE twisted filament. Three types of PTFE composite yarn are produced by using PTFE, PPS, and aramid filaments as core yarns and the other two as outer layers. The PTFE twisted filament is used as the weft yarn, and the three types of PTFE composite yarn are combined with the PTFE twisted filament as the warp yarn, achieving the processing of a PTFE filter fabric with both excellent strength and breathability.

[0005] This invention provides a method for producing PTFE filter fabric, comprising the following steps: Step 1: PTFE twisted filament processing Vinylon and PTFE filaments are fed together into a ring spinning machine. After feeding without drafting, they are twisted and plied to produce Vinylon / PTFE plied yarn. After high-temperature setting, the Vinylon filaments are removed, while the crimp formed by twisting and plying the PTFE filaments is effectively retained, thus producing PTFE twisted filament. The drafting and twisting system of the ring spinning machine is equipped with a yarn guiding device including a mounting frame, an arc-shaped connecting piece, and a spiral yarn guide hook. The arc-shaped connecting piece is rotatably connected to the mounting frame, and the spiral yarn guide hook is detachably connected to the arc-shaped connecting piece. This allows for position adjustment to keep the spiral yarn guide hook and the yarn tube concentric, enabling efficient plying of vinylon and PTFE filaments. Step 2: Composite Yarn Processing PTFE, PPS, and aramid filaments are spun together using a double-wrap parallel spinning mechanism to obtain PTFE, PPS, and aramid as core yarns, and the other two filaments as the first, second, and third composite yarns of the outer sheath; Step 3: Mixed Weaving Process PTFE twisted filament is used as the weft yarn, and PTFE twisted filament and first, second and third composite yarns are used as the warp yarns to make PTFE filter fabric. In the warp yarn, one PTFE twisted filament and one first, second and one third composite yarn are used as a combination. In a combination, one PTFE twisted filament is used as a warp yarn, and one first, second and one third composite yarn are used as a warp yarn. Each warp yarn is controlled to move up and down independently.

[0006] In the production method of the PTFE filter fabric described above, preferably, in the composite yarn processing, PTFE filament is selected as the core yarn, and PPS and aramid filaments are respectively the outer layers to obtain a first composite yarn in which PPS and aramid filaments are simultaneously wrapped around PTFE filament from both sides; PPS filament is selected as the core yarn, and PTFE and aramid filaments are respectively the outer layers to obtain a second composite yarn in which PTFE and aramid filaments are simultaneously wrapped around PPS filament from both sides; and aramid filament is selected as the core yarn, and PTFE and PPS filaments are respectively the outer layers to obtain a third composite yarn in which PTFE and PPS filaments are simultaneously wrapped around aramid filament from both sides.

[0007] In the production method of the PTFE filter fabric described above, preferably, the drafting system includes a rear drafting roller pair, a middle drafting roller pair, and a front drafting roller pair. Each of the rear, middle, and front drafting roller pairs includes a lower drafting roller and an upper drafting roller. The lower drafting roller of the front drafting roller pair is connected to a drafting motor, and the transmission connection between the lower drafting rollers of the rear and middle drafting roller pairs and the lower drafting rollers of the front drafting roller pair is disconnected.

[0008] In the production method of PTFE filter fabric described above, preferably, the twisting system includes a spindle, which is connected to a spindle disc on a main shaft via a spindle belt. The main shaft is connected to a main motor. A yarn tube is nested on the spindle, and a ring plate is provided on the yarn tube. The ring plate passes through the yarn tube through a ring insertion hole, and a ring is fixedly provided in the ring insertion hole. A wire loop straddles the ring's track.

[0009] In the production method of PTFE filter fabric as described above, preferably, the mounting frame is set at the front of the spinning machine table, and the mounting frame includes a left fixed connecting piece and a right fixed connecting piece with the same structure. The left and right fixed connecting pieces are rectangular. The left fixed connecting piece is vertically oriented and its rear side is fixedly connected to the front side of the platform. The right fixed connecting piece is vertically oriented and its rear side is fixedly connected to the front side of the platform. The left and right fixed connecting pieces are arranged in a symmetrical structure and maintain a certain distance between them. The line connecting the center of the area between the left and right fixed connecting pieces and the center of the spindle is vertical. A left support piece is provided on the upper side of the right side of the left fixed connecting piece. The left support piece is a rectangular piece and is set horizontally. The left side of the left support piece is fixedly connected to the upper side of the right side of the left fixed connecting piece, and the front side of the left support piece is aligned with the front side of the left fixed connecting piece. A right support piece is provided on the upper side of the left side of the right fixed connecting piece. The right support piece is a rectangular piece and is set in a horizontal direction. The right side of the right support piece is fixedly connected to the upper side of the left side of the right fixed connecting piece, and the front side of the right support piece is aligned with the front side of the right fixed connecting piece. A certain distance is maintained between the right side of the left support piece and the left side of the right support piece, and a rotating connecting pin is provided on the platform above the area between the left and right fixed connecting pieces.

[0010] In the above-described method for producing PTFE filter fabric, preferably, the cross-section of the rotating connecting pin is arc-shaped, the rotating connecting pin is arranged along the length direction of the workbench, both ends of the rotating connecting pin are open, and the rotating connecting pin is fixedly connected to the workbench. A rotating connecting rod is provided inside the rotating connecting pin. The rotating connecting rod is a solid cylindrical structure. The rotating connecting rod is sleeved inside the rotating connecting pin, so that the rotating connecting rod can rotate freely after being sleeved, and both ends of the rotating connecting rod extend out of the rotating connecting pin.

[0011] In the production method of the PTFE filter fabric described above, preferably, an arc-shaped connecting piece is connected to the rotating connecting pin, the arc-shaped connecting piece including a connecting piece body, and the connecting piece body including a connecting piece and an arc-shaped piece.

[0012] In the production method of PTFE filter fabric described above, preferably, the connecting piece is an isosceles trapezoidal piece, and an mounting pin is provided on the long lower base edge of the connecting piece. The mounting pin includes a left mounting pin and a right mounting pin with identical structures. The left and right mounting pins include mounting pin pieces and mounting pin bodies; The mounting pin is a rectangular piece. The mounting pin of the left mounting pin is fixedly connected to the left point of the long bottom edge of the connecting piece, and the mounting pin of the right mounting pin is fixedly connected to the right point of the long bottom edge of the connecting piece. The mounting pin is a hollow cylinder with open ends. The mounting pin is set horizontally and its length direction is consistent with the length direction of the bottom of the mounting pin piece. The side of the mounting pin is fixedly connected to the bottom of the mounting pin piece. The mounting pin of the left mounting pin is sleeved on the left end of the extended rotating connecting pin of the rotating connecting rod and the two are fixedly connected. The mounting pin of the right mounting pin is sleeved on the right end of the extended rotating connecting pin of the rotating connecting rod and the two are fixedly connected, thus realizing the connection between the arc-shaped connecting piece and the mounting connecting frame. An arc-shaped piece is provided on the short upper bottom edge of the connecting piece. The arc-shaped piece is a semi-circular piece, and the diameter of the arc-shaped piece is the same as the length of the short upper bottom edge of the connecting piece. The diameter side of the arc-shaped piece is fixedly connected to the short upper bottom edge of the connecting piece to form a complete connecting piece body.

[0013] In the production method of the PTFE filter fabric described above, preferably, a lower baffle is provided on the lower side of the connecting piece body, the lower baffle is provided along the outer side of the lower side of the connecting piece body, and the upper side of the lower baffle is fixedly connected to the outer side of the lower side of the connecting piece body. A fixing pin device is provided on the lower side of the connecting piece body; The fixed connecting pin device includes 3-6 rows of fixed connecting pins arranged symmetrically. Each row of fixed connecting pins includes 3-6 fixed connecting pins. The fixed connecting pins are arranged vertically along the length of the connecting plate body. The fixed connecting pins are hollow cylindrical structures with open ends. The height of the fixed connecting pins is less than the height of the lower baffle. The upper circular surface of the fixed connecting pin is fixedly connected to the lower side of the connecting plate body. The fixed connecting pin has a fixed internal spiral pattern, and there is an insertion hole on the lower baffle directly in front of the middle position of two adjacent rows of fixed connecting pins. The number of insertion holes is between 2 and 5.

[0014] In the production method of PTFE filter fabric described above, preferably, a spiral yarn guide hook is provided on the arc-shaped connecting piece, and the spiral yarn guide hook includes a yarn guide rod; The yarn guide rod is a solid iron cylindrical structure with an embedded arc device at one end. The material and cross-section of the embedded arc device are the same as those of the yarn guide rod. The embedded arc device includes a left row of embedded arcs and a right row of embedded arcs. The left row of embedded arcs and the right row of embedded arcs are arranged in parallel and symmetrical arrangement. The left row of embedded arcs and the right row of embedded arcs include two arc-shaped embedded arcs. The notch of the embedded arc of the left row of embedded arcs is located on the right side and is fixedly connected to the left side of the yarn guide rod. The notch of the embedded arc of the right row of embedded arcs is located on the left side and is fixedly connected to the right side of the yarn guide rod. The spacing between the two embedded arcs in each row is different from the spacing between two adjacent fixed connecting pins in each row; A yarn guide hook is provided at the other end of the yarn guide rod. The yarn guide hook has a spiral structure. One end of the yarn guide hook is fixedly connected to the yarn guide rod. An operating rod is provided at the other end of the yarn guide hook. The operating rod has a solid iron cylindrical structure. One end of the operating rod is fixedly connected to the yarn guide hook at a certain angle. Compared with existing technologies, this invention employs vinylon filament and PTFE filament, which are fed into a ring spinning machine without drafting. The ring spinning machine is equipped with a yarn guiding device including a mounting frame, an arc-shaped connecting piece, and a spiral yarn guide hook. The arc-shaped connecting piece is rotatably connected to the mounting frame, and the spiral yarn guide hook is detachably connected to the arc-shaped connecting piece. This allows for positional adjustment of the yarn guide hook and yarn tube during use, maintaining concentricity and achieving efficient plying. Furthermore, the spiral structure design of the yarn guide hook ensures proper yarn shaping during use. It is easy to insert, which facilitates actual operation; then, through high-temperature setting, the vinylon filament is removed, and the crimp formed by the twisting of PTFE filaments is effectively preserved, resulting in PTFE twisted filaments with improved cohesion; by using PTFE, PPS and aramid filaments as core yarns and the other two as outer layers, three kinds of PTFE composite yarns are produced; PTFE twisted filaments are used as weft yarns, and the three kinds of PTFE composite yarns are combined with PTFE twisted filaments as warp yarns, realizing the processing of PTFE filter fabrics with both excellent strength and breathability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the yarn guiding device provided in an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached drawings: 1-Spinning machine platform, 2-Left fixed connecting piece, 3-Right fixed connecting piece, 4-Left support piece, 5-Right support piece, 6-Rotating connecting pin, 7-Rotating connecting rod, 8-Left mounting pin, 9-Right mounting pin, 10-Mounting pin piece, 11-Mounting pin body, 12-Connecting piece, 13-Arc-shaped piece, 14-Lower stop piece, 15-Fixed connecting pin, 16-Embedding opening, 17-Yarn guide rod, 18-Left row embedding arc, 19-Right row embedding arc, 20-Embedding arc, 21-Yarn guide hook, 22-Operating rod. Detailed Implementation

[0017] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] This invention provides a method for producing PTFE filter fabric, comprising the following steps: Step 1: PTFE twisted filament processing Vinylon filament and PTFE filament are fed together into a ring spinning machine without drafting and then twisted to produce a vinylon / PTFE twisted yarn. The vinylon / PTFE twisted yarn is then subjected to a high-temperature setting treatment to remove the vinylon filament while effectively retaining the crimp formed by the twisting of the PTFE filament in the vinylon / PTFE twisted yarn, thus producing a PTFE twisted filament.

[0019] Ring spinning machines include a drafting system and a twisting system.

[0020] The drafting system includes a rear drafting roller pair, a middle drafting roller pair, and a front drafting roller pair. Each of the rear, middle, and front drafting roller pairs includes a lower drafting roller and an upper drafting roller. The lower drafting roller of the front drafting roller pair is connected to the drafting motor. The transmission connection between the lower drafting rollers of the rear and middle drafting roller pairs and the lower drafting roller of the front drafting roller pair is disconnected.

[0021] The twisting system includes a spindle, which is connected to a spindle disc on a main shaft via a spindle belt. The main shaft is connected to a main motor. A yarn tube is nested on the spindle, and a ring plate is set on the yarn tube. The ring plate passes through the yarn tube through a ring insertion hole. A ring is fixedly set in the ring insertion hole, and a wire loop straddles the ring's track.

[0022] A yarn guiding device is installed between the drafting system and the twisting system, as shown in the reference. Figure 1 As shown, the yarn guiding device includes a mounting frame, an arc-shaped connecting piece, and a spiral yarn guiding hook.

[0023] The mounting bracket is located at the front of the spinning machine platform 1. The mounting bracket includes a left fixed connecting piece 2 and a right fixed connecting piece 3 with the same structure.

[0024] The left fixed connecting piece 2 and the right fixed connecting piece 3 are rectangular pieces. The left fixed connecting piece 2 is set vertically and its rear side is fixedly connected to the front side of the platform. The right fixed connecting piece 3 is set vertically and its rear side is fixedly connected to the front side of the platform. The left fixed connecting piece 2 and the right fixed connecting piece 3 are arranged in a symmetrical structure and maintain a certain distance between them. The line connecting the center of the area between the left fixed connecting piece 2 and the right fixed connecting piece 3 and the center of the spindle is vertical.

[0025] A left support piece 4 is provided on the upper side of the right side of the left fixed connecting piece 2. The left support piece 4 is a rectangular piece and is arranged horizontally. The left side of the left support piece 4 is fixedly connected to the upper side of the right side of the left fixed connecting piece 2. The front side of the left support piece 4 is aligned with the front side of the left fixed connecting piece 2.

[0026] A right support piece 5 is provided on the upper side of the left side of the right fixed connecting piece 3. The right support piece 5 is a rectangular piece and is arranged horizontally. The right side of the right support piece 5 is fixedly connected to the upper side of the left side of the right fixed connecting piece 3. The front side of the right support piece 5 is aligned with the front side of the right fixed connecting piece 3.

[0027] A certain distance is maintained between the right side of the left support piece 4 and the left side of the right support piece 5. A rotating connecting pin 6 is provided on the platform above the area between the left fixed connecting piece 2 and the right fixed connecting piece 3.

[0028] The rotary connecting pin 6 has an arc-shaped cross-section. The rotary connecting pin 6 is set along the length of the platform. Both ends of the rotary connecting pin 6 are open, and the rotary connecting pin 6 is fixedly connected to the platform.

[0029] A rotating connecting rod 7 is provided inside the rotating connecting pin 6. The rotating connecting rod 7 is a solid cylindrical structure. The rotating connecting rod 7 is sleeved inside the rotating connecting pin 6, so that the rotating connecting rod 7 can rotate freely after being sleeved, and both ends of the rotating connecting rod 7 extend out of the rotating connecting pin 6.

[0030] An arc-shaped connecting piece is connected to the rotary connecting pin 6. The arc-shaped connecting piece includes a connecting piece body, which includes a connecting piece 12 and an arc-shaped piece 13.

[0031] The connecting piece 12 is an isosceles trapezoidal piece, and a mounting pin is provided on the long lower base of the connecting piece 12. The mounting pin includes a left mounting pin 8 and a right mounting pin 9 with identical structures.

[0032] The left mounting pin 8 and the right mounting pin 9 include mounting pin piece 10 and mounting pin body 11.

[0033] Mounting pin 10 is a rectangular piece. Mounting pin 10 of left mounting pin 8 is fixedly connected to the left side of the long bottom edge of connecting piece 12, and mounting pin 10 of right mounting pin 9 is fixedly connected to the right side of the long bottom edge of connecting piece 12.

[0034] The mounting pin 11 is a hollow cylinder with open ends. The mounting pin 11 is set horizontally and its length direction is consistent with the length direction of the lower bottom of the mounting pin piece 10. The side of the mounting pin 11 is fixedly connected to the lower bottom of the mounting pin piece 10. The mounting pin 11 of the left mounting pin 8 is sleeved on the left end of the extended rotating connecting pin 6 of the rotating connecting rod 7 and the two are fixedly connected. The mounting pin 11 of the right mounting pin 9 is sleeved on the right end of the extended rotating connecting pin 6 of the rotating connecting rod 7 and the two are fixedly connected, realizing the connection between the arc-shaped connecting piece and the mounting connecting frame.

[0035] An arc-shaped piece 13 is provided on the short upper bottom edge of the connecting piece 12. The arc-shaped piece 13 is a semi-circular piece. The diameter of the arc-shaped piece 13 is the same as the length of the short upper bottom edge of the connecting piece 12. The diameter side of the arc-shaped piece 13 is fixedly connected to the short upper bottom edge of the connecting piece 12 to form a complete connecting piece body.

[0036] A lower baffle 14 is provided on the lower side of the connecting piece body. The lower baffle 14 is provided along the outer side of the lower side of the connecting piece body, and the upper side of the lower baffle 14 is fixedly connected to the outer side of the lower side of the connecting piece body. A fixing pin 15 device is provided on the lower side of the connecting piece body.

[0037] The fixed connecting pin 15 device includes 3-6 rows of fixed connecting pins 15 arranged symmetrically. Each row of fixed connecting pins 15 includes 3-6 fixed connecting pins 15. The fixed connecting pins 15 are arranged vertically along the length of the connecting piece body. The fixed connecting pins 15 are hollow cylindrical structures with open ends. The height of the fixed connecting pins 15 is less than the height of the lower baffle 14. The upper circular surface of the fixed connecting pins 15 is fixedly connected to the lower side surface of the connecting piece body.

[0038] A fixed inner spiral pattern is provided inside the fixed connecting pin 15, and an insertion port 16 is opened on the lower baffle 14 directly in front of the middle position of two adjacent rows of fixed connecting pins 15. The number of insertion ports 16 is between 2 and 5.

[0039] A spiral yarn guide hook is provided on the arc-shaped connecting piece, and the spiral yarn guide hook includes a yarn guide rod 17.

[0040] The yarn guide rod 17 is a solid iron cylindrical structure, and an embedded arc 20 device is provided on one end of the yarn guide rod 17.

[0041] The material and cross-section of the embedded arc 20 device are the same as those of the yarn guide rod 17. The embedded arc 20 device includes a left row of embedded arcs 18 and a right row of embedded arcs 19. The left row of embedded arcs 18 and the right row of embedded arcs 19 are arranged in a parallel and symmetrical manner. The left row of embedded arcs 18 and the right row of embedded arcs 19 include two arc-shaped embedded arcs 20. The notch of the embedded arc 20 of the left row of embedded arcs 18 is located on the right side and is fixedly connected to the left side of the yarn guide rod 17. The notch of the embedded arc 20 of the right row of embedded arcs 19 is located on the left side and is fixedly connected to the right side of the yarn guide rod 17.

[0042] The spacing between the two embedded arcs 20 in each row is different from the spacing between two adjacent fixed connecting pins 15 in each row.

[0043] A yarn guide hook 21 is provided at the other end of the yarn guide rod 17. The yarn guide hook 21 has a spiral structure. One end of the yarn guide hook 21 is fixedly connected to the yarn guide rod 17 to achieve a fixed connection between the yarn guide hook 21 and the yarn guide rod 17. An operating rod 22 is provided at the other end of the yarn guide hook 21. The operating rod 22 has a solid iron cylindrical structure. One end of the operating rod 22 is fixedly connected to the yarn guide hook 21 at a certain angle.

[0044] When using it, first install the yarn guide device concentrically.

[0045] First, connect the arc-shaped connecting piece to the spiral yarn guide hook.

[0046] During connection, based on the left and right positions of the yarn tube, select and fix the embedding arcs 20 of the left row embedding arc 18 and the right row embedding arc 19 to the corresponding positions of the two adjacent rows of fixing connecting pins 15 on the connecting piece body; then, based on the front and rear positions of the yarn tube, select and fix the embedding arcs 20 of the left row embedding arc 18 and the right row embedding arc 19 to the corresponding positions of the fixing connecting pins 15 in the selected two rows of fixing connecting pins 15 on the connecting piece body.

[0047] During fixing, the embedding arcs 20 of the left row embedding arc 18 and the right row embedding arc 19 are respectively fitted onto the corresponding fixed connecting pins 15 of the fixing connecting pin 15 device of the connecting piece body. At this time, the inserted fixed connection is aligned with the embedding arc 20. Then, the corresponding screws are screwed into the fixing connecting pins 15. During the screwing process, the outer spiral thread of the screw is screwed into the inner spiral thread of the fixing connecting pin 15, so that the screw head and the embedding arc 20 are pressed into contact with a certain pressure, thereby realizing the fixed installation of the spiral yarn guide hook on the connecting piece body. After fixing, the yarn guide rod 17 of the spiral yarn guide hook is embedded in the embedding port 16, so that the yarn guide hook 21 of the spiral yarn guide hook extends out of the arc-shaped connecting piece.

[0048] During spinning, an external force is applied to the operating lever 22, causing the arc-shaped connecting piece to rotate and fall under its own weight. After falling, the arc-shaped connecting piece is supported by the left support piece 4 and the right support piece 5 of the connecting frame, so that the arc-shaped connecting piece remains horizontal with the spinning machine table 1.

[0049] Vinylon filament and PTFE filament are fed into the front nip formed by the pressing of the lower drafting roller and the upper drafting roller of the front drafting roller pair at a certain distance. After being driven by the synchronously rotating lower drafting roller and upper drafting roller, they are continuously output. The output Vinylon filament and PTFE filament are directly plied together by the twisting effect generated by the twisting system to produce Vinylon / PTFE plied yarn. One end of the Vinylon / PTFE plied yarn remaining on the yarn bobbin is pulled out by hand. The pulled-out Vinylon / PTFE plied yarn passes through the guide hook 21 of the steel wire traveler and the spiral guide hook, and is then pressed at the front nip of the drafting system of the spinning machine to realize the production joint, thereby realizing the continuous production of Vinylon / PTFE plied yarn.

[0050] The main shaft drives the spindle to rotate via a belt, which in turn drives the yarn tube to rotate synchronously. The rotation of the yarn tube then drives the vibratory / PTFE ply yarn wound on it to rotate, which in turn drives the steel traveler passing through it to rotate along its track. Due to the weight of the steel traveler itself and the friction between it and the track, the rotation speed of the steel traveler is less than that of the yarn tube. The speed difference between the two causes the vibratory / PTFE ply yarn to be continuously wound on the yarn tube. The rotation of the steel traveler then causes the vibratory / PTFE ply yarn to rotate axially, which in turn adds twist to the vibratory / PTFE ply yarn. The added twist is transmitted upward along the length of the vibratory / PTFE ply yarn. When it is transmitted to the yarn guide device, the twist transmission is hindered by the support of the yarn guide hook 21 on the vibratory / PTFE ply yarn. At this time, because the yarn guide hook 21 and the yarn tube are kept in a concentric position, the uniformity and stability of plying are greatly improved, thus improving the plying efficiency.

[0051] When the yarn breaks or spinning stops, an external force is applied to the operating lever 22, causing the arc-shaped connecting piece to rotate and rise under the action of the external force. After it has fully risen, the arc-shaped connecting piece remains vertical to the spinning machine platform 1, so that the arc-shaped connecting piece rests against the spinning machine platform 1. When splicing the yarn, an external force is applied to the operating lever 22, causing the arc-shaped connecting piece to rotate and fall under its own weight, thereby completing the splicing of the yarn.

[0052] Step 2: Composite Yarn Processing PTFE composite yarn is obtained by spinning PTFE, PPS, and aramid filaments together using a double-wrap parallel spinning machine. During processing, PTFE filament is used as the core yarn, and PPS and aramid filaments are used as outer layers to produce a first composite yarn in which PPS and aramid filaments are simultaneously wrapped around PTFE filaments from both sides. PPS filament is used as the core yarn, and PTFE and aramid filaments are used as outer layers to produce a second composite yarn in which PTFE and aramid filaments are simultaneously wrapped around PPS filaments from both sides. A third composite yarn is obtained in which aramid filament is used as the core yarn, and PTFE and PPS filaments are used as outer layers to produce a third composite yarn in which PTFE and PPS filaments are simultaneously wrapped around aramid filaments from both sides.

[0053] Step 3: Mixed Weaving Process PTFE twisted filament is used as the weft yarn, and PTFE twisted filament, first composite yarn, second composite yarn, and third composite yarn are used as the warp yarn for mixed weaving. In the warp yarn, one PTFE twisted filament, one first composite yarn, one second composite yarn, and one third composite yarn are used as a combination. In a combination, one PTFE twisted filament is used as a warp yarn, and one first composite yarn, one second composite yarn, and one third composite yarn are used together as a warp yarn, and each warp yarn is controlled independently for up and down movement.

[0054] Using 55.6 tex PTFE twisted filament as weft yarn, and 60 tex first composite yarn, second composite yarn, and third composite yarn, along with 55.6 tex PTFE twisted filament as warp yarn, a filter fabric with a warp density of 140 ends / 10 cm, a weft density of 85 ends / 10 cm, and a plain weave is produced. Among the first, second, and third composite yarns, 250 dtex aramid filament bundles, 150 dtex PPS filament bundles, and 200 dtex PTFE filament bundles are selected for the corresponding composite yarn processing, including the following steps: Warping: A KY601 slitting warping machine is used, with the process configuration principle being "medium-low speed, uniform tension, damage prevention, and uniform winding"; the process parameters are set as follows: displacement 0.99 mm, number of slits 7, 455 strands per slit, slit width 34.9 cm, warping speed 185 m / min, rewinding speed 81 m / min, and rewinding tension 0.41 MPa; Threading the reed: Use the straight threading method, one thread per reed, reed size 135 teeth / 10 cm; ensure that the surface of the relevant parts woven on the machine is smooth and free of burrs.

[0055] Weaving: Follow the process principle of "low speed, low tension, and late shedding"; machine speed is 345 r / min, long back beam is used, back beam height is 19cm, warp stop height is 5.5cm, heddle leveling time is 300°, and heddle frame height is (138±2)mm during heddle leveling; static electricity generated by friction between warp and weft yarns is reduced by installing static elimination devices and humidifiers on the loom.

[0056] The fabric properties were tested, and the results are as follows:

[0057] The above description, based on the embodiments shown in the figures, details the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A method for producing a PTFE filter fabric, characterized in that, Includes the following steps: Step 1: PTFE twisted filament processing Vinylon and PTFE filaments are fed together into a ring spinning machine. After feeding without drafting, they are twisted and plied to produce Vinylon / PTFE plied yarn. After high-temperature setting, the Vinylon filaments are removed, while the crimp formed by twisting and plying the PTFE filaments is effectively retained, thus producing PTFE twisted filament. The drafting and twisting system of the ring spinning machine is equipped with a yarn guiding device including a mounting frame, an arc-shaped connecting piece, and a spiral yarn guide hook. The arc-shaped connecting piece is rotatably connected to the mounting frame, and the spiral yarn guide hook is detachably connected to the arc-shaped connecting piece. This allows for position adjustment to keep the spiral yarn guide hook and the yarn tube concentric, enabling efficient plying of vinylon and PTFE filaments. Step 2: Composite Yarn Processing PTFE, PPS, and aramid filaments are spun together using a double-wrap parallel spinning mechanism to obtain PTFE, PPS, and aramid as core yarns, and the other two filaments as the first, second, and third composite yarns of the outer sheath; Step 3: Mixed Weaving Process PTFE twisted filament is used as the weft yarn, and PTFE twisted filament and first, second and third composite yarns are used as the warp yarns to make PTFE filter fabric. In the warp yarn, one PTFE twisted filament and one first, second and one third composite yarn are used as a combination. In a combination, one PTFE twisted filament is used as a warp yarn, and one first, second and one third composite yarn are used as a warp yarn. Each warp yarn is controlled to move up and down independently.

2. The method for producing a PTFE filter fabric according to claim 1, characterized in that, In the processing of composite yarns, PTFE filament is selected as the core yarn, and PPS and aramid filaments are used as the outer layers to produce a first composite yarn in which PPS and aramid filaments are simultaneously wrapped around PTFE filament from both sides. PPS filament is selected as the core yarn, and PTFE and aramid filaments are used as the outer layers to produce a second composite yarn in which PTFE and aramid filaments are simultaneously wrapped around PPS filament from both sides. A third composite yarn in which PTFE and PPS filaments are simultaneously wrapped around aramid filament from both sides is produced by using aramid filament as the core yarn and PTFE and PPS filaments as the outer layers.

3. The method for producing a PTFE filter fabric according to claim 1, characterized in that, The drafting system includes a rear drafting roller pair, a middle drafting roller pair, and a front drafting roller pair. Each of the rear, middle, and front drafting roller pairs includes a lower drafting roller and an upper drafting roller. The lower drafting roller of the front drafting roller pair is connected to the drafting motor. The transmission connection between the lower drafting rollers of the rear and middle drafting roller pairs and the lower drafting roller of the front drafting roller pair is disconnected.

4. The method for producing a PTFE filter fabric according to claim 1, characterized in that, The twisting system includes a spindle, which is connected to a spindle disc on a main shaft via a spindle belt. The main shaft is connected to a main motor. A yarn tube is nested on the spindle, and a ring plate is set on the yarn tube. The ring plate passes through the yarn tube through a ring insertion hole. A ring is fixedly set in the ring insertion hole, and a wire loop straddles the ring's track.

5. The method for producing a PTFE filter fabric according to claim 1, characterized in that, The mounting bracket is located at the front of the spinning machine platform. The mounting bracket includes a left fixed connecting piece and a right fixed connecting piece with the same structure. The left and right fixed connecting pieces are rectangular. The left fixed connecting piece is vertically oriented and its rear side is fixedly connected to the front side of the platform. The right fixed connecting piece is vertically oriented and its rear side is fixedly connected to the front side of the platform. The left and right fixed connecting pieces are arranged in a symmetrical structure and maintain a certain distance between them. The line connecting the center of the area between the left and right fixed connecting pieces and the center of the spindle is vertical. A left support piece is provided on the upper side of the right side of the left fixed connecting piece. The left support piece is a rectangular piece and is set horizontally. The left side of the left support piece is fixedly connected to the upper side of the right side of the left fixed connecting piece, and the front side of the left support piece is aligned with the front side of the left fixed connecting piece. A right support piece is provided on the upper side of the left side of the right fixed connecting piece. The right support piece is a rectangular piece and is set in a horizontal direction. The right side of the right support piece is fixedly connected to the upper side of the left side of the right fixed connecting piece, and the front side of the right support piece is aligned with the front side of the right fixed connecting piece. A certain distance is maintained between the right side of the left support piece and the left side of the right support piece, and a rotating connecting pin is provided on the platform above the area between the left and right fixed connecting pieces.

6. A method for producing a PTFE filter fabric according to claim 5, characterized in that, The rotating connecting pin has an arc-shaped cross-section and is set along the length of the platform. Both ends of the rotating connecting pin are open, and the rotating connecting pin is fixedly connected to the platform. A rotating connecting rod is provided inside the rotating connecting pin. The rotating connecting rod is a solid cylindrical structure. The rotating connecting rod is sleeved inside the rotating connecting pin, so that the rotating connecting rod can rotate freely after being sleeved, and both ends of the rotating connecting rod extend out of the rotating connecting pin.

7. A method for producing a PTFE filter fabric according to claim 6, characterized in that, An arc-shaped connecting piece is connected to the rotary connecting pin. The arc-shaped connecting piece includes a connecting piece body, and the connecting piece body includes a connecting piece and an arc-shaped piece.

8. The method for producing a PTFE filter fabric according to claim 7, characterized in that, The connecting piece is an isosceles trapezoidal piece, and a mounting pin is provided on the long lower base of the connecting piece. The mounting pin includes a left mounting pin and a right mounting pin with exactly the same structure. The left and right mounting pins include mounting pin pieces and mounting pin bodies; The mounting pin is a rectangular piece. The mounting pin of the left mounting pin is fixedly connected to the left point of the long bottom edge of the connecting piece, and the mounting pin of the right mounting pin is fixedly connected to the right point of the long bottom edge of the connecting piece. The mounting pin is a hollow cylinder with open ends. The mounting pin is set horizontally and its length direction is consistent with the length direction of the bottom of the mounting pin piece. The side of the mounting pin is fixedly connected to the bottom of the mounting pin piece. The mounting pin of the left mounting pin is sleeved on the left end of the extended rotating connecting pin of the rotating connecting rod and the two are fixedly connected. The mounting pin of the right mounting pin is sleeved on the right end of the extended rotating connecting pin of the rotating connecting rod and the two are fixedly connected, thus realizing the connection between the arc-shaped connecting piece and the mounting connecting frame. An arc-shaped piece is provided on the short upper bottom edge of the connecting piece. The arc-shaped piece is a semi-circular piece, and the diameter of the arc-shaped piece is the same as the length of the short upper bottom edge of the connecting piece. The diameter side of the arc-shaped piece is fixedly connected to the short upper bottom edge of the connecting piece to form a complete connecting piece body.

9. A method for producing a PTFE filter fabric according to claim 8, characterized in that, A lower baffle is provided on the lower side of the connecting piece body. The lower baffle is provided along the outer side of the lower side of the connecting piece body, and the upper side of the lower baffle is fixedly connected to the outer side of the lower side of the connecting piece body. A fixing pin device is provided on the lower side of the connecting piece body; The fixed connecting pin device includes 3-6 rows of fixed connecting pins arranged symmetrically. Each row of fixed connecting pins includes 3-6 fixed connecting pins. The fixed connecting pins are arranged vertically along the length of the connecting plate body. The fixed connecting pins are hollow cylindrical structures with open ends. The height of the fixed connecting pins is less than the height of the lower baffle. The upper circular surface of the fixed connecting pin is fixedly connected to the lower side of the connecting plate body. The fixed connecting pin has a fixed internal spiral pattern, and there is an insertion hole on the lower baffle directly in front of the middle position of two adjacent rows of fixed connecting pins. The number of insertion holes is between 2 and 5.

10. A method for producing a PTFE filter fabric according to claim 7, characterized in that, A spiral yarn guide hook is provided on the arc-shaped connecting piece, and the spiral yarn guide hook includes a yarn guide rod; The yarn guide rod is a solid iron cylindrical structure with an embedded arc device at one end. The material and cross-section of the embedded arc device are the same as those of the yarn guide rod. The embedded arc device includes a left row of embedded arcs and a right row of embedded arcs. The left row of embedded arcs and the right row of embedded arcs are arranged in parallel and symmetrical arrangement. The left row of embedded arcs and the right row of embedded arcs include two arc-shaped embedded arcs. The notch of the embedded arc of the left row of embedded arcs is located on the right side and is fixedly connected to the left side of the yarn guide rod. The notch of the embedded arc of the right row of embedded arcs is located on the left side and is fixedly connected to the right side of the yarn guide rod. The spacing between the two embedded arcs in each row is different from the spacing between two adjacent fixed connecting pins in each row; A yarn guide hook is provided at the other end of the yarn guide rod. The yarn guide hook has a spiral structure. One end of the yarn guide hook is fixedly connected to the yarn guide rod. An operating rod is provided at the other end of the yarn guide hook. The operating rod has a solid iron cylindrical structure. One end of the operating rod is fixedly connected to the yarn guide hook at a certain angle.

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