A twisted net and its mesh-gradient weaving method

Abstract

This invention discloses a twisted net and its step-by-step weaving method, belonging to the field of rope and net manufacturing technology for aquaculture. It includes a net sheet woven from twisted bundles of ultra-high molecular weight polyethylene (UHMWPE) film-split fibers. The net sheet is formed by cross-twisting warp and weft film-split fiber bundles to form knots, with meshes formed between adjacent knots. The net sheet is characterized by being divided into at least two weaving sections with different mesh sizes along the warp and / or weft directions, with a transition weaving section between adjacent sections. Within the transition weaving section, the mesh size increases or decreases sequentially along the warp or weft direction according to a preset step-by-step variation, forming a stepped mesh distribution. Through the linkage design of the tension adjustment mechanism and the mesh size control mechanism, stepless continuous adjustment of the mesh size from large to small is achieved, overcoming the defect of traditional technologies where the mesh size can only change discretely, and significantly expanding the applicability of the net sheet product.

Description

Technical Field

[0001] This invention relates to the field of rope and net manufacturing technology for aquaculture, and more specifically, to a twisted net and a method for weaving the net mesh at progressively smaller sizes. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber has broad application prospects in aquaculture, marine engineering, and safety protection due to its excellent abrasion resistance, aging resistance, high strength, and low elongation. Currently, UHMWPE materials based on the membrane splitting method are gradually being used in the manufacture of products such as ropes and non-woven fabrics.

[0003] Patent CN107012582A discloses a processing method for high-strength polyethylene twisted netting, including primary benzene vapor setting, cooling, and secondary hot steam setting. Compared to existing technologies, this invention has the following advantages: By adding composite additives to the high-strength polyethylene monofilament raw material, the tensile mechanical properties are improved while slightly increasing the thread density. Simultaneously, the primary stretching and initial benzene vapor setting of the woven netting modify the netting, making its spatial structure more complex and its molecular structure more compact, thus increasing its strength. The combination of secondary stretching and hot steam setting reduces the shrinkage rate of the netting, ensuring the quality of the fishing net. Compared to netting of the same specifications, the breaking strength is increased by approximately 3.5%, making it more widely applicable.

[0004] Although the device has many beneficial effects, in the field of mesh manufacturing, traditional polyethylene mesh is mostly made by monofilament weaving or twisting. In the traditional mesh manufacturing process, the adjustment of mesh size usually requires changing the loom specifications, changing the shuttle configuration, or adjusting the process parameters. The adjustment process is cumbersome and time-consuming, and the mesh size changes discretely, making it impossible to achieve a continuous and smooth size transition. Summary of the Invention (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a twisted net and a method for weaving the net at progressively smaller mesh sizes, thus solving the aforementioned problems. (II) Technical Solution

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: a twisted mesh and its mesh-gradual weaving method, comprising a mesh sheet woven from ultra-high molecular weight polyethylene film-split fiber bundles, wherein the mesh sheet is formed by cross-twisting of warp and weft film-split fiber bundles to form knots, and meshes are formed between adjacent knots; characterized in that the mesh sheet is divided into at least two weaving sections with different mesh sizes along the warp and / or weft directions, and a transition weaving section is provided between adjacent weaving sections; within the transition weaving section, the mesh size increases sequentially along the warp or weft direction according to a preset step-by-step variation amount. The mesh size is increased or decreased to form a stepped mesh distribution; the gradual change in mesh size is achieved by adjusting the tension, warp speed, or cross angle of the warp and weft membrane fiber bundles in stages during the weaving process; the transition weaving section includes at least two step-by-step sections, with the mesh size remaining consistent within each step, and the difference in mesh size between adjacent steps being 1mm to 20mm; the length of the transition weaving section is 3 to 20 times the maximum mesh size within that transition weaving section; the weaving section and the transition weaving section extend continuously on the mesh, and the mesh can be used directly without cutting.

[0007] Preferably, the weaving section includes a first weaving section, a second weaving section, and a third weaving section arranged sequentially along the warp direction. The mesh size of the first weaving section is larger than that of the second weaving section, and the mesh size of the second weaving section is larger than that of the third weaving section. A transition weaving section is provided between adjacent weaving sections. The number of step-by-step steps in the transition weaving section is 2 to 10, and the weaving length of each step is equal or unequal. The mesh size is measured in half-mesh units, with the mesh size of the first weaving section being 80mm to 200mm, the mesh size of the second weaving section being 40mm to 80mm, and the mesh size of the third weaving section being 5mm to 40mm. The step-by-step steps in the transition weaving section are arranged in descending or ascending order of mesh size.

[0008] Preferably, the twisted net further includes a mesh size detection unit and a feedback control unit. The detection unit is located at the netting outlet of the twisted netting equipment and is used to monitor the mesh size of the current weaving section or transition weaving section in real time. The feedback control unit is signal-connected to the detection unit and adjusts the tension adjustment mechanism or warp feeding mechanism according to the deviation between the detection result and the preset step-by-step weaving program, so that the mesh size is stabilized at the target value of the corresponding step. The detection unit is a visual inspection device or a laser rangefinder with a detection accuracy of ±0.1mm. The feedback control unit also records the actual mesh size of each step and issues an alarm or performs automatic compensation when the deviation exceeds ±0.5mm.

[0009] Preferably, the ultra-high molecular weight polyethylene membrane fiber has a viscosity-average molecular weight of 1 million to 6 million, a thickness of 20 μm to 100 μm, and a slit width of 6 mm to 18 mm; the mesh shape is one or more of rhombus, square, and rectangular; the mesh size, in half-mesh units, is 5 mm to 200 mm; the linear density of the warp membrane fiber bundle and the weft membrane fiber bundle is the same or different, with a linear density range of 500 tex to 5000 tex; the surface of the membrane fiber bundle has microfibrillated filaments, with a filament length not exceeding 2 mm.

[0010] Preferably, the mesh knot is provided with an anti-slip edge sealing structure, which includes a mechanical locking unit, an anti-detachment connecting line, and a hot-pressed edge sealing layer. The mechanical locking unit is formed by splitting the warp and weft membrane fiber bundles into 2 to 6 sub-fiber bundles at their intersections. The sub-fiber bundles interweave and are then twisted together twice to form an irreversible mechanical interlock. The anti-detachment connecting line extends along the mesh arrangement direction, passes through adjacent mesh knots in sequence, and is wrapped and fixed with the fiber bundles at the mesh knots. Its linear density is less than that of the main fiber bundle. The hot-pressed edge sealing layer is formed by melting and re-curing the surface layer of ultra-high molecular weight polyethylene fiber at the mesh knots and the root of the mesh feet on both sides of the mesh knots. It covers the outside of the mechanical locking unit and welds and fixes the anti-detachment connecting line.

[0011] Preferably, the perimeter of the mesh sheet is provided with an edge sealing strip, which is formed by hot-pressing and melting the ends of the warp and weft fiber bundles at the edge of the mesh sheet and then integrating them with the hot-pressed sealing layer at the edge knot; the edge sealing strip is arranged continuously or intermittently along the edge of the mesh sheet, and reinforcing sealing points are provided at intervals on the edge sealing strip, and the anti-detachment connecting line at the reinforcing sealing point is folded back and wrapped and fixed with the edge knot; the width of the edge sealing strip is 5mm to 15mm, and the thickness is 0.1mm to 0.5mm; the mesh size of the area where the edge sealing strip is located is less than or equal to the mesh size of the adjacent weaving section.

[0012] A method for weaving twisted net mesh at progressively smaller mesh sizes includes the following steps: S1. Prepare ultra-high molecular weight polyethylene film-splitting fiber bundles, wherein the film-splitting fiber bundles are cut from ultra-high molecular weight polyethylene films with a viscosity-average molecular weight of 1 million to 6 million by a film-splitting device, with a thickness of 20 μm to 100 μm and a width of 6 mm to 18 mm. S2. The membrane split fiber bundles are fed into a CNC twisting and weaving equipment as warp and weft fibers to cross-twist and weave, forming a mesh with the initial mesh size; S3. During the weaving process, the mesh is divided into at least two weaving sections and one transition weaving section along the warp and weft directions according to the preset step-by-step weaving procedure. S4. Maintain constant tension, warp feed speed, and cross angle within each weaving section to form the mesh size corresponding to that section; S5. Within the transition weaving section, the tension, warp feed speed, or cross angle are changed in stages to gradually increase or decrease the mesh size, while maintaining a preset weaving length or weaving time between each level to form a stepped mesh. S6. After completing the weaving, roll it up or cut it.

[0013] Preferably, within the transition weaving section, the change in mesh size at each level is achieved through the following method: first, the tension of the weft fiber bundle is reduced or increased to the target value, while simultaneously adjusting the warp fiber bundle feed speed to change the crossing angle between the warp and weft fiber bundles; after the mesh size detection unit confirms that the current mesh size has reached the target value for that level, the parameters for that level remain unchanged, and weaving continues until the preset weaving length for that level is reached; then, the next level of adjustment is entered until the transition weaving section ends; the transition time for each level of adjustment does not exceed 5 seconds, and the stable weaving length for each level is 10mm to 500mm; the tension adjustment uses a tension roller or magnetic powder brake, and the warp feed speed adjustment uses a servo motor drive.

[0014] Preferably, the progressive weaving program includes at least three mesh size levels, with a mesh size difference of 1mm to 20mm between adjacent levels; the tension adjustment is stepless continuous adjustment, with a tension variation range of 0.5N to 50N; the twisting weaving equipment is a CNC twisting weaving machine, and the progressive weaving program is integrated with the CNC system, automatically switching parameters at each level through a preset program; the preset program also includes instructions for performing anti-slip knot sealing treatment on the knots in the weaving section and transition weaving section; the CNC system is also connected to a touch screen or host computer for inputting progressive weaving parameters and monitoring the weaving status.

[0015] Preferably, in the weaving section and transition weaving section, the knots are further treated with anti-slip edge sealing: at each knot, the warp and weft fiber bundles are split into 2 to 6 sub-fiber bundles, interlaced and twisted twice to form a mechanical lock; anti-detachment connecting lines are set along the mesh arrangement direction and pass through each knot; then, a hot-pressing treatment of 120°C to 160°C and 0.5MPa to 5.0MPa is applied to the knots and the root of the mesh feet on both sides of the knots for 1 to 10 seconds to form a hot-pressed edge sealing layer; after cooling and curing, the knots are rolled up; the hot-pressing treatment uses an edge sealing mold, which has a groove adapted to the shape of the knot and mesh foot clearance grooves located on both sides of the groove; during cooling and curing, a tension of 0.1MPa to 1.0MPa is applied to the mesh. (III) Beneficial Effects

[0016] Compared with the prior art, the present invention provides a twisted net and a method for weaving the net at different mesh levels, which has the following beneficial effects: 1. This twisted net and its mesh-by-mesh weaving method, through the linkage design of tension adjustment mechanism and mesh size control mechanism, realizes stepless continuous adjustment of mesh size from large to small, overcomes the defect of traditional technology where mesh size can only be changed discretely, and significantly expands the application range of net products.

[0017] 2. This twisted net and its mesh-by-mesh weaving method allow for mesh adjustment without stopping the machine to replace parts or reset the equipment. Adjustments can be completed online during production, significantly improving production efficiency and equipment utilization. Through closed-loop control consisting of a detection unit and a feedback control unit, the mesh size adjustment accuracy can reach ±0.5mm, and the mesh uniformity and consistency after adjustment are good, effectively ensuring the stability of product quality.

[0018] 3. This twisted net and its mesh-by-mesh weaving method use film-split fibers to replace traditional ultra-high molecular weight polyethylene monofilaments, which significantly reduces material costs; at the same time, the stepless mesh adjustment function allows the same equipment to produce products of various specifications, significantly improving the return on investment of the equipment.

[0019] 4. This twisted net and its mesh-by-mesh weaving method, the ultra-high molecular weight polyethylene film-split fiber twisted net has excellent properties such as high strength, high wear resistance, and aging resistance, and can fully meet the application needs of high-performance and cost-effective netting in deep-sea aquaculture, marine engineering and other fields. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a process flow diagram of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-2 The present invention provides a technical solution: Example 1

[0023] This embodiment provides a twisted net with three weaving sections and two transition weaving sections along the warp direction, and describes its step-by-step weaving process.

[0024] (1) Preparation of membrane-splitted fibers: Ultra-high molecular weight polyethylene film with a viscosity-average molecular weight of 3 million was selected and cut into membrane-splitted fiber bundles with a thickness of 50 μm and a width of 12 mm using a membrane splitting device. The blade spacing was set to 12 mm during cutting, and the traction speed was controlled at 8 m / min, so that a small number of microfibrillated filaments were generated at the edge of the fiber bundle. The filament length was about 0.5 mm to 1.5 mm, which is beneficial to the cohesion during subsequent twisting. The linear density of the obtained fiber bundle was about 2200 tex.

[0025] (2) Equipment Preparation: A CNC twisted web weaving machine is used. This machine is equipped with warp and weft tension adjustment mechanisms. The tension adjustment uses a magnetic powder brake, the warp feed speed is driven by a servo motor, and the crossover angle is adjusted by the yarn guide arm. The CNC system has a built-in step-by-step weaving program and is connected to a mesh size detection unit. The detection unit is a vision inspection device installed at the web exit, with a detection accuracy of ±0.1mm. The operator inputs the parameters of each weaving section and transition weaving section through the touch screen.

[0026] (3) Step-by-step weaving: The membrane-split fiber bundles are fed into the weaving machine as warp and weft fibers respectively. The weaving is done sequentially along the warp direction: First weaving section: Half mesh size is set to 100mm, weaving length is 5m. In this section, the tension adjustment mechanism applies a weft tension of 8N, the warp feed speed is constant, the cross angle is maintained at 90°, and the mesh shape is diamond-shaped. The detection unit monitors in real time, and the feedback control unit stabilizes the mesh size at 100mm ± 0.3mm.

[0027] The first transition weaving section: The mesh size gradually decreases from 100mm to 50mm, with five progressively smaller steps. The mesh size difference between each step is 10mm, resulting in 90mm, 80mm, 70mm, 60mm, and 50mm respectively. The stable weaving length for each step is 300mm. The total length of the transition section is approximately 1.8m, which is 18 times the maximum mesh size of 100mm within this section. During weaving, as the machine enters each step, the tension adjustment mechanism gradually increases the weft tension from 8N ​​to 12N, while the warp feed speed is reduced by 5% by the servo motor, and the cross angle is gradually adjusted from 90° to 78°. The transition time for each adjustment is approximately 3 seconds. After the detection unit confirms that the current mesh size has reached the target value for that step, the parameters remain unchanged, and weaving continues until the preset length before moving to the next step. The mesh size decreases in a stepped manner throughout the entire transition section without any machine stops.

[0028] Second weaving section: Half mesh size set at 50mm, weaving length 5m. Tension stabilized at 12N, cross angle 78°, and detection unit confirmed mesh size stabilized at 50mm±0.3mm.

[0029] The second transition weaving section: The mesh size gradually decreases from 50mm to 20mm, with three progressively smaller steps, each with a difference of 10mm, 10mm, and 10mm (40mm, 30mm, 20mm). Each step has a stable weaving length of 200mm. The total length of the transition section is approximately 0.8m. The tension gradually increases from 12N to 18N, the warp feed speed is then reduced by 8%, and the crossover angle is adjusted from 78° to 65°. Each transition takes approximately 2.5 seconds.

[0030] Third weaving section: Half mesh size is set at 20mm, weaving length is 5m. Tension is stabilized at 18N, cross angle is 65°, and mesh size is stabilized at 20mm±0.3mm.

[0031] (4) Anti-slip edge sealing treatment: During the weaving process, anti-slip edge sealing is performed simultaneously on each knot. Specifically, at each knot, the warp and weft fiber bundles are separated into 3 sub-fiber bundles using a splitting needle. First, the warp sub-fiber bundles and weft sub-fiber bundles are interlaced, then reversed and twisted a second time in the opposite direction to the initial twist. The twist of the second twist is 110 twists per meter, which is about 35% higher than the twist of the initial knot. Then, an anti-slip connecting line is set along the radial direction of the mesh, with a linear density of 1000 tex, which is about 45% of the linear density of the main fiber bundle. It passes through each knot and wraps around the fiber bundle at the knot twice. After that, the knot and the area about 2 mm at the root of the knot on both sides are hot-pressed using an edge sealing mold. The heating temperature is 140℃, the pressure is 2.0 MPa, and the time is 5 seconds. After hot pressing, the mesh is allowed to cool naturally to room temperature. During cooling, a tension of 0.3 MPa is applied to the mesh. The hot-pressed edge sealing layer is approximately 0.15mm thick and covers the outside of the mechanical locking unit, while the anti-detachment connecting wire is welded and fixed.

[0032] (5) Winding and Testing: Winding is performed after weaving is completed. Testing showed that the twisted net produced in this embodiment exhibited a 55% increase in breaking strength at the mesh connection points in the first weaving section compared to traditional twisted nets of the same specifications, and a 50% increase in the third weaving section. The mesh size showed a clear step-like change within the transition sections, with natural transitions between adjacent steps, and the net was free of holes or loosening. In a simulated water flow impact test, after 200 hours of continuous impact, the mesh size change rate was less than 2%. Example 2

[0033] The difference between this embodiment and Embodiment 1 lies in the fiber raw material, mesh size range, number of transition steps, and hot-pressing edge sealing parameters.

[0034] (1) Preparation of membrane split fibers: Select ultra-high molecular weight polyethylene film with a viscosity-average molecular weight of 5 million, cut it into membrane split fiber bundles with a thickness of 30 μm and a width of 8 mm, with a linear density of about 1500 tex.

[0035] (2) Gradual weaving: Two weaving sections and one transition weaving section are set along the warp direction. The first weaving section has a half mesh size of 150mm and a weaving length of 4m; the transition weaving section gradually decreases from 150mm to 30mm, with 6 steps, the differences being 20mm, 20mm, 20mm, 20mm, 20mm, 20mm, 20mm, i.e., 130mm, 110mm, 90mm, 70mm, 50mm, 30mm. The stable weaving length of each step is 250mm, and the total length of the transition section is about 1.5m. The second weaving section has a half mesh size of 30mm and a weaving length of 4m. The mesh shape is square. During weaving, the tension is gradually increased from 6N to 20N, the warp feed speed is gradually decreased, and the cross angle is adjusted from 90° to 60°. The detection unit is a laser rangefinder with a detection accuracy of ±0.1mm. The feedback control unit automatically compensates for the tension when the deviation exceeds ±0.5mm. The transition time for each step does not exceed 4 seconds.

[0036] (3) Anti-slip edge sealing treatment: The sub-fiber bundle at the knot is split into 4 strands, and the secondary twist is 150 twists per meter, which is 50% higher than the initial knot twist. The anti-slip connecting line is set along both the warp and weft directions, with a linear density of 600 tex, which is about 40% of the linear density of the main fiber bundle. The warp and weft anti-slip connecting lines are crossed and wound at the knot to form an anti-slip network. Hot pressing edge sealing is performed using an edge sealing mold with a groove depth of 0.4 mm and a clearance groove width of 4 mm. The heating temperature is 150℃, the pressure is 3.0 MPa, and the time is 4 seconds. Cooling is performed by air cooling for 10 seconds followed by water cooling to room temperature, with a tension of 0.5 MPa applied during cooling.

[0037] (4) Testing: The breaking strength of the mesh connection point is about 60% higher than that of traditional twisted mesh. By manually cutting three adjacent meshes, the anti-detachment connection line effectively prevents the spread of delamination, and the damage range is controlled within four meshes. Within the transition section of mesh size, the size deviation of each step does not exceed ±0.4mm. Example 3

[0038] This embodiment focuses on explaining the control logic and specific operation of the CNC system during the step-by-step weaving process.

[0039] The same membrane-split fiber bundles and CNC twisting web weaving machine as in Example 1 were used. A step-by-step weaving program was entered on the touchscreen, and the program included the following parameter table: Weaving section 1: half mesh 100mm, length 5m, weft tension 8N, warp feed speed 100%, cross angle 90°.

[0040] Transition Section 1: Step 1 half-mesh 90mm, length 300mm, tension 9N, warp feed speed 98%, cross angle 87°; Step 2 half-mesh 80mm, length 300mm, tension 10N, warp feed speed 96%, cross angle 84°; Step 3 half-mesh 70mm, length 300mm, tension 11N, warp feed speed 94%, cross angle 81°; Step 4 half-mesh 60mm, length 300mm, tension 12N, warp feed speed 92%, cross angle 78°; Step 5 half-mesh 50mm, length 300mm, tension 13N, warp feed speed 90%, cross angle 75°.

[0041] Weaving section 2: half mesh 50mm, length 5m, weft tension 13N, warp feed speed 90%, cross angle 75°.

[0042] During the weaving process, the vision detection unit captures an image of the mesh every 0.5 seconds, calculates the current mesh size through image processing, and transmits the data to the feedback control unit. The feedback control unit compares the measured value with the program setting value. If the deviation is within ±0.3mm, no action is taken; if the deviation exceeds ±0.3mm but is less than ±0.5mm, the tension adjustment mechanism is finely adjusted by 2% of the set tension; if the deviation exceeds ±0.5mm, an alarm is issued and weaving is paused, awaiting operator confirmation. In actual operation, the mesh size at each step remains stable within the target value of ±0.3mm, the total length of the transition section is 1.8m, the weaving time is approximately 45 seconds, and no machine stoppage is required throughout the entire process. Example 4

[0043] This embodiment illustrates the setting of edge sealing strips and reinforcing edge sealing points.

[0044] Based on Example 1, when the mesh is woven to the edge, approximately 20mm of the warp and weft fiber bundle ends at the edge knots are left uncut. During hot-press sealing, these end fiber bundles are folded back along the edge of the mesh and placed into the sealing mold together with the hot-press sealing layer at the edge knots. The sealing mold has a widened groove at the edge, with a groove width of 8mm. The heating temperature is 140℃, the pressure is 2.5MPa, and the time is 6 seconds. After the surface layer of the end fiber bundles melts, it fuses with the hot-press sealing layer of the edge knots. After cooling, a continuous edge sealing strip is formed, approximately 8mm wide and 0.3mm thick. A reinforcing sealing point is set every 5 knots on the edge sealing strip. At the reinforcing sealing point, the anti-detachment connecting line is folded back, wrapped around the edge knot three times, and then pressed into the hot-press sealing layer. Tests show that the breaking strength of the edge knots is about 35% higher than that of the mesh without edge sealing strips, the mesh edges do not detach, and the overall dimensional stability is good. Example 5

[0045] This embodiment provides a rectangular mesh twisted wire, and uses a large molecular weight range and a wide range of process parameters.

[0046] (1) Preparation of membrane split fibers: Select ultra-high molecular weight polyethylene film with a viscosity-average molecular weight of 4 million, cut it into membrane split fiber bundles with a thickness of 80 μm and a width of 16 mm, with a linear density of about 3500 tex.

[0047] (2) Gradual weaving: Three weaving sections and two transition sections are set along the warp direction. The first weaving section has a half mesh size of 200mm×120mm (rectangular) and a length of 3m; the transition section 1 gradually decreases from 200mm×120mm to 100mm×60mm, with 4 steps, each step having a size difference of 25mm×15mm, and a stable weaving length of 200mm; the second weaving section has a half mesh size of 100mm×60mm and a length of 3m; the transition section 2 gradually decreases from 100mm×60mm to 40mm×25mm, with 3 steps, each step having a size difference of 20mm×12mm, and a stable weaving length of 150mm; the third weaving section has a half mesh size of 40mm×25mm and a length of 3m. The tension is gradually increased from 5N to 25N, the warp feed speed is gradually decreased, and the cross angle is adjusted from 90° to 60°. The detection unit is a laser rangefinder, and the feedback control unit automatically compensates.

[0048] (3) Anti-slip edge sealing treatment: The fiber bundle at the knot is split into two strands, and the secondary twist is 100 twists per meter, which is about 42% higher than the initial knot twist. Anti-slip connecting lines are set along both the warp and weft directions, with a linear density of 800 tex, which is about 23% of the linear density of the main fiber bundle. The hot-pressing edge sealing temperature is 130℃, the pressure is 1.5MPa, and the time is 8 seconds. Natural cooling is used, and a tension of 0.4MPa is applied during cooling. The thickness of the hot-pressing edge sealing layer is about 0.25mm.

[0049] (4) Testing: The breaking strength at the mesh connection point is about 50% higher than that of traditional twisted mesh. The mesh size remains stable after long-term use and no obvious deformation occurs. In the step transition section, the long and short side dimensions of the rectangular mesh change according to the preset steps, with a deviation of no more than ±0.5mm.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A twisted net, comprising a net sheet woven from twisted bundles of ultra-high molecular weight polyethylene film-split fibers, wherein the net sheet is formed by cross-twisting of warp and weft film-split fiber bundles to form knots, and meshes are formed between adjacent knots; characterized in that, The mesh is divided into at least two weaving sections with different mesh sizes along the warp and weft directions, and a transition weaving section is provided between adjacent weaving sections. Within the transition weaving section, the mesh size increases or decreases sequentially along the warp or weft direction according to a preset step-by-step change, forming a stepped mesh distribution. The step-by-step change in mesh size is achieved by adjusting the tension, warp feed speed, or cross angle of the warp and / or weft membrane fiber bundles in stages during the weaving process. The transition weaving section includes at least two step-by-step steps, and the mesh size remains consistent within each step-by-step step, with a mesh size difference of 1mm to 20mm between adjacent step-by-step steps. The length of the transition weaving section is 3 to 20 times the maximum mesh size within the transition weaving section. The weaving sections and transition weaving sections extend continuously on the mesh, and the mesh can be used directly without cutting.

2. The twisted wire mesh according to claim 1, characterized in that, The weaving section includes a first weaving section, a second weaving section, and a third weaving section arranged sequentially along the warp direction. The mesh size of the first weaving section is larger than that of the second weaving section, and the mesh size of the second weaving section is larger than that of the third weaving section. A transition weaving section is provided between adjacent weaving sections. The number of steps in the transition weaving section is 2 to 10, and the weaving length of each step is equal or unequal. The mesh size is measured in half-mesh units. The mesh size of the first weaving section is 80mm to 200mm, the mesh size of the second weaving section is 40mm to 80mm, and the mesh size of the third weaving section is 5mm to 40mm. The steps in the transition weaving section are arranged in descending or ascending order of mesh size.

3. The twisted wire mesh according to claim 1, characterized in that, The twisted net also includes a mesh size detection unit and a feedback control unit. The detection unit is located at the netting outlet of the twisted netting equipment and is used to monitor the mesh size of the current weaving section or transition weaving section in real time. The feedback control unit is signal-connected to the detection unit and adjusts the tension adjustment mechanism or warp feeding mechanism according to the deviation between the detection result and the preset step-by-step weaving program, so that the mesh size is stabilized at the target value of the corresponding step. The detection unit is a visual inspection device or a laser rangefinder with a detection accuracy of ±0.1mm. The feedback control unit also records the actual mesh size of each step and issues an alarm or performs automatic compensation when the deviation exceeds ±0.5mm.

4. The twisted net according to claim 1, characterized in that, The ultra-high molecular weight polyethylene membrane fiber has a viscosity-average molecular weight of 1 million to 6 million, a thickness of 20 μm to 100 μm, and a slit width of 6 mm to 18 mm; the mesh shape is one or more of rhombus, square, and rectangular; the mesh size, measured in half-mesh units, is 5 mm to 200 mm; the linear density of the warp membrane fiber bundle and the weft membrane fiber bundle is the same or different, with a linear density range of 500 tex to 5000 tex; the surface of the membrane fiber bundle has microfibrillated filaments, with a filament length not exceeding 2 mm.

5. The twisted wire mesh according to claim 1, characterized in that, The mesh knots are provided with an anti-slip edge sealing structure, which includes a mechanical locking unit, an anti-detachment connecting line, and a hot-pressed edge sealing layer. The mechanical locking unit is formed by splitting the warp and weft membrane fiber bundles into 2 to 6 sub-fiber bundles at their intersections. The sub-fiber bundles interweave and are then twisted together twice to form an irreversible mechanical interlock. The anti-detachment connecting line extends along the mesh arrangement direction, passes through adjacent mesh knots in sequence, and is wrapped and fixed with the fiber bundles at the mesh knots. Its linear density is less than that of the main fiber bundle. The hot-pressed edge sealing layer is formed by melting and re-solidifying the surface layer of ultra-high molecular weight polyethylene fiber at the mesh knots and the root of the mesh feet on both sides of the mesh knots. It covers the outside of the mechanical locking unit and welds and fixes the anti-detachment connecting line.

6. The twisted wire mesh according to claim 1, characterized in that, The mesh is provided with an edge sealing strip around its perimeter. The edge sealing strip is formed by hot-pressing and melting the ends of the warp and weft fiber bundles at the edge of the mesh and then bonding them together with the hot-pressed sealing layer at the edge knot. The edge sealing strip is arranged continuously or intermittently along the edge of the mesh, and reinforced sealing points are provided at intervals on the edge sealing strip. The anti-detachment connecting line at the reinforced sealing point is folded back and wrapped and fixed with the edge knot. The width of the edge sealing strip is 5mm to 15mm and the thickness is 0.1mm to 0.5mm. The mesh size of the area where the edge sealing strip is located is less than or equal to the mesh size of the adjacent weaving section.

7. The method for progressively weaving the mesh of the twisted net according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Prepare ultra-high molecular weight polyethylene film-splitting fiber bundles, wherein the film-splitting fiber bundles are cut from ultra-high molecular weight polyethylene films with a viscosity-average molecular weight of 1 million to 6 million by a film-splitting device, with a thickness of 20 μm to 100 μm and a width of 6 mm to 18 mm. S2. The membrane split fiber bundles are fed into a CNC twisting and weaving equipment as warp and weft fibers to cross-twist and weave, forming a mesh with the initial mesh size; S3. During the weaving process, the mesh is divided into at least two weaving sections and one transition weaving section along the warp and weft directions according to the preset step-by-step weaving procedure. S4. Maintain constant tension, warp feed speed, and cross angle within each weaving section to form the mesh size corresponding to that section; S5. Within the transition weaving section, the tension, warp feed speed, or cross angle are changed in stages to gradually increase or decrease the mesh size, while maintaining a preset weaving length or weaving time between each level to form a stepped mesh. S6. After completing the weaving, roll it up or cut it.

8. The method for progressively weaving twisted mesh according to claim 7, characterized in that, Within the transition weaving section, the change in mesh size at each level is achieved by first reducing or increasing the tension of the weft fiber bundle to the target value, while simultaneously adjusting the warp feed speed of the warp fiber bundle to change the crossing angle between the warp and weft fiber bundles. Once the mesh size detection unit confirms that the current mesh size has reached the target value for that level, the parameters for that level remain unchanged, and weaving continues until the preset weaving length for that level is reached; then, the next level of adjustment is entered until the transition weaving section ends; the transition time for each level of adjustment does not exceed 5 seconds, and the stable weaving length for each level is 10mm to 500mm; the tension adjustment is achieved using a tension roller or magnetic powder brake, and the warp feed speed adjustment is achieved using a servo motor drive.

9. The method for progressively weaving twisted mesh according to claim 7, characterized in that, The progressive weaving program includes at least three mesh size levels, with a mesh size difference of 1mm to 20mm between adjacent levels; the tension adjustment is stepless continuous adjustment, with a tension variation range of 0.5N to 50N; the twisting weaving equipment is a CNC twisting weaving machine, and the progressive weaving program is integrated with the CNC system, automatically switching parameters at each level through a preset program; the preset program also includes instructions for anti-slip knot sealing treatment of the knots in the weaving section and transition weaving section; the CNC system is also connected to a touch screen or host computer for inputting progressive weaving parameters and monitoring the weaving status.

10. The method for progressively weaving twisted mesh according to claim 7, characterized in that, Within the weaving section and transition weaving section, the knots are further treated with anti-slip edge sealing: at each knot, the warp and weft fiber bundles are split into 2 to 6 sub-fiber bundles, interlaced and then twisted twice to form a mechanical lock; anti-detachment connecting lines are set along the mesh arrangement direction and pass through each knot; then, a hot-pressing treatment of 120°C to 160°C and 0.5MPa to 5.0MPa is applied to the knots and the root of the mesh feet on both sides of the knots for 1 to 10 seconds to form a hot-pressed edge sealing layer; after cooling and curing, the knots are rolled up; the hot-pressing treatment uses an edge sealing mold, which has a groove adapted to the shape of the knot and mesh foot clearance grooves located on both sides of the groove; during cooling and curing, a tension of 0.1MPa to 1.0MPa is applied to the mesh.

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