A screw extruder and a spinning, drawing and winding combined machine

Abstract

This invention discloses a screw extruder and a spinning, drawing, and winding combined machine, relating to the field of spinning production technology. It solves the technical problem that screw extruders cannot be used simultaneously for the production of fine denier industrial filaments of various polyester fibers. The screw of the screw extruder includes a feeding section, a compression section, and a metering section connected in sequence. The metering section includes a first metering section, a second metering section, a third metering section, and a conical torpedo head connected in sequence. The bottom of the screw groove of the first metering section has several straight grooves, the length direction of which is the same as the axial direction of the screw. The second metering section has equidistant threads, and the periphery of the third metering section is uniformly arranged with diamond-shaped blocks to form splines. This allows for a larger screw length design for the screw extruder, enabling various polyester materials such as PET, PBT, and PTT to be heated, melted, compressed, and mixed over a longer process. This allows the same screw extruder to be used for the production of various polyester fibers, providing a foundation for producing multiple polyester fibers with a single device.

Description

Technical Field

[0001] This invention relates to the field of spinning production technology, and in particular to a screw extruder and a spinning, drawing and winding combined machine. Background Technology

[0002] Polyester fibers, including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polypropylene terephthalate (PTT), have broad prospects in the industrial sector. However, producing fine denier industrial filaments from PET, PBT, and PTT fibers involves three different production lines. The resulting large production lines, extensive floor space, and high production costs can weaken competitiveness.

[0003] The production equipment involves a screw extruder. To develop a production equipment suitable for producing fine denier industrial filaments from the three types of fibers mentioned above, the primary issue to address is the versatility of the screw extruder. Summary of the Invention

[0004] This application provides a screw extruder and a spinning, drawing and winding combined machine, which solves the technical problem in the related art that screw extruders cannot be used simultaneously for the production of industrial filaments of various polyester fibers of fine denier.

[0005] This application provides a screw extruder. The screw of the screw extruder includes a feeding section, a compression section, and a metering section connected in sequence. The metering section includes a first metering section, a second metering section, a third metering section, and a conical torpedo head connected in sequence. The first metering section is connected to the compression section. The bottom of the screw groove of the first metering section is provided with several straight grooves. The length direction of the straight grooves is the same as the axial direction of the screw. The second metering section is provided with equidistant threads. The periphery of the third metering section is uniformly arranged with diamond blocks to form splines.

[0006] Optionally, multiple straight grooves are evenly spaced at the bottom of the screw groove of the first metering section, and the groove walls at both ends of the length of the straight grooves are located on the screw ridges of the first metering section.

[0007] Optionally, the screw extruder is used for the production of industrial filaments of fine denier polyester, with the length-to-diameter ratio (L / D) of the screw controlled between 26:1 and 30:1; and the compression ratio of the screw controlled between 2.19 and 2.5.

[0008] Optionally, L = 28D, the length of the feeding section is 9D, the length of the compression section is 5D, the length of the first metering section is 3D, the length of the second metering section is 7D, the length of the third metering section is 3D, and the length of the conical torpedo head is 1D.

[0009] Optionally, the heating zone of the screw is divided into 6 zones along the axial direction. The first and second zones correspond to the feeding section, the third zone corresponds to the compression section, and the fourth, fifth, and sixth zones correspond to the metering section.

[0010] When using PET chips to spin polyester fine denier industrial filaments, the heating temperatures of zones one through six are 285℃, 292℃, 295℃, 295℃, 291℃, and 287℃, respectively.

[0011] The die head pressure of the screw extruder is 12 MPa.

[0012] Optionally, the heating zone of the screw is divided into 6 zones along the axial direction. The first and second zones correspond to the feeding section, the third zone corresponds to the compression section, and the fourth, fifth, and sixth zones correspond to the metering section.

[0013] When using PBT chips to spin polyester fine denier industrial filaments, the heating temperatures of zones one through six are 280℃, 295℃, 292℃, 290℃, 290℃, and 285℃, respectively.

[0014] The die head pressure of the screw extruder is 10 MPa.

[0015] Optionally, the heating zone of the screw is divided into 6 zones along the axial direction. The first and second zones correspond to the feeding section, the third zone corresponds to the compression section, and the fourth, fifth, and sixth zones correspond to the metering section.

[0016] When using PTT chips to spin polyester fine denier industrial filaments, the heating temperatures of zones one through six are 285℃, 290℃, 296℃, 296℃, 293℃, and 288℃, respectively.

[0017] The die head pressure of the screw extruder is 11 MPa.

[0018] Optionally, the compression ratio of the screw is 2.21.

[0019] Optionally, the chip viscosity used for spinning polyester fine denier industrial filaments is controlled at 0.95-1.05.

[0020] A spinning, drawing, and winding combined machine, including the aforementioned screw extruder, is used for the production of various polyester fine denier industrial filaments.

[0021] The beneficial effects of this application are as follows: A screw extruder is provided, wherein the screw includes a feeding section, a compression section, and a metering section. The metering section is arranged sequentially along its length as a first metering section, a second metering section, a third metering section, and a conical torpedo head. The bottom of the screw groove in the first metering section has several straight grooves, the length of which is the same as the axial direction of the screw. When the melt enters the metering section from the compression section, it undergoes melting and a change of direction of motion in the first metering section. Upon entering the second metering section from the first metering section, the melt's direction of motion changes again. Upon entering the third metering section from the second metering section, the melt's direction of motion changes once more along the spline. Finally, the melt passes through the conical torpedo head... The melt is introduced into the screw extruder through a three-stage change in melt direction, ensuring thorough mixing and melting. This reduces shear heat and the straight groove design of the first metering section further reduces shear heat and shear rate, making it easier for the melt to move forward in the screw extruder. This allows for a longer screw design, enabling various polyester materials such as PET, PBT, and PTT to be heated, melted, compressed, and mixed over a longer process. This not only improves spinning quality but also allows the same screw extruder to be used for the production of various polyester fibers, providing a foundation for producing multiple polyester fibers with a single device. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0023] Figure 1 This application provides an overall structural schematic diagram of a screw extruder;

[0024] Figure 2 for Figure 1 A schematic diagram of the screw's specific structure;

[0025] Figure 3 for Figure 2 A schematic diagram of the specific structure of the middle metering section;

[0026] Figure 4 for Figure 2 The diagram shows the division of the screw heating zone;

[0027] Figure 5 for Figure 1 A magnified view of a section of the conical torpedo head.

[0028] Attached diagram labels: 1-1-Screw, 1-1-1-Feed section, 1-1-2-Compression section, 1-1-3-Metering section, 1-1-3a-First metering section, 1-1-3a-1-Straight groove, 1-1-3b-Second metering section, 1-1-3c-Third metering section, 1-1-3d-Conical torpedo head, 1-1-4a-First zone, 1-1-4b-Second zone, 1-1-4c-Third zone Zone 3, 1-1-4d-Zone 4, 1-1-4e-Zone 5, 1-1-4f-Zone 6, 1-2-Screw sleeve, 1-3-Heating coil, 1-4-Temperature measuring element, 1-5-Screw extruder drive component, 1-6-Discharge cooling component, 1-7-Hopper, 1-8-Nitrogen inlet, 1-9-Screw extruder frame, 1-10-Screw extruder insulation cover, 1-11-Pressure measuring element. Detailed Implementation

[0029] This application provides a screw extruder and a spinning, drawing, and winding combined machine, which solves the technical problem in the related art that screw extruders cannot be used simultaneously for the production of industrial filaments of various polyester fibers in fine denier.

[0030] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0031] A screw extruder, wherein the screw of the screw extruder includes a feeding section, a compression section and a metering section connected in sequence. The metering section includes a first metering section, a second metering section, a third metering section and a conical torpedo head connected in sequence. The first metering section is connected to the compression section. The bottom of the screw groove of the first metering section is provided with several straight grooves. The length direction of the straight grooves is the same as the axial direction of the screw. The second metering section is provided with equidistant threads. The periphery of the third metering section is uniformly arranged with diamond blocks to form splines.

[0032] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0033] This embodiment provides a screw extruder; please refer to [reference needed]. Figure 1 This includes a threaded sleeve 1-2, a threaded rod 1-1 passing through the threaded sleeve 1-2, and a heating coil 1-3 installed outside the threaded sleeve 1-2. Please refer to [reference needed]. Figure 2 The screw 1-1 includes a feeding section 1-1-1, a compression section 1-1-2, and a metering section 1-1-3, which are connected in sequence.

[0034] In the screw extruder of this embodiment, please refer to Figure 2Along the axial direction of screw 1-1, metering section 1-1-3 is divided into four parts: first metering section 1-1-3a, second metering section 1-1-3b, third metering section 1-1-3c, and conical torpedo head 1-1-3d. These four parts are connected sequentially. The end of first metering section 1-1-3a furthest from second metering section 1-1-3b is connected to the end of compression section 1-1-2 furthest from feed section 1-1-1. Furthermore, please refer to... Figure 3 The bottom of the screw groove of the first metering section 1-1-3a is provided with several straight grooves 1-1-3a-1. The length direction of the straight grooves 1-1-3a-1 is the same as the axial direction of the screw 1-1. The second metering section 1-1-3b is provided with equidistant threads. The periphery of the third metering section 1-1-3c is evenly arranged with rhomboid blocks to form a spline.

[0035] Specifically, the screw 1-1 of the screw extruder has a uniquely determined length-to-diameter ratio and compression ratio. To achieve the melting of different polyester chips into a melt using the same extruder, the inventors have adopted the method of increasing the length of the screw 1-1 on the current equipment specifications, which is reflected in increasing the length-to-diameter ratio of the original screw.

[0036] To increase the length of the original screw, the inventors decided to lengthen the metering section 1-1-3. Furthermore, based on the existing equipment specifications, the increased length of metering section 1-1-3 increases the positive flow rate of the melt and reduces the shearing effect of the polyester melt. However, the lengthening of metering section 1-1-3 leads to a certain reduction in the overall heating efficiency of the screw extruder, and also reduces the viscosity drop of the polyester in the region from the head to the tail of the screw, while correspondingly reducing the reverse flow rate of the melt.

[0037] The above-described solution in this embodiment will be described in detail, such as... Figure 3As shown, the first metering section 1-1-3a includes a screw ridge, and a screw groove is formed between the screw ridges. The first metering section 1-1-3a has several straight grooves 1-1-3a-1 at the bottom of the screw groove. The straight grooves 1-1-3a-1 have a length direction, which is the same as the axial direction of the screw 1-1. When the compression section 1-1-2 feeds material to the first metering section 1-1-3a, the melt enters the screw groove of the first metering section 1-1-3a and moves along the screw groove. When the melt passes through the straight groove 1-1-3a-1 area, the melt is affected by the straight groove 1-1-3a-1 and will have a tumbling motion area near the straight groove 1-1-3a-1, and will tumble. The rotation direction of this tumbling is similar to the length direction of the straight groove 1-1-3a-1. When the tumbling motion occurs near the straight groove 1-1-3a-1, the melt is also affected by the screw edge. Under the combined action of the straight groove 1-1-3a-1 and the screw edge, the melt will produce a three-dimensional tumbling, thus playing a role in diverting and mixing.

[0038] On the other hand, the first metering section 1-1-3a with straight grooves 1-1-3a-1 also reduces the shear rate of the melt, making the melt less prone to decomposition; compared with the circular cross-section of a conventional screw, the first metering section 1-1-3a with straight grooves 1-1-3a-1 has a larger contact area with the melt, which improves the melt extrusion effect. Under the same screw speed, the screw 1-1 of this embodiment has a higher conveying capacity than a conventional screw.

[0039] Furthermore, the first metering section 1-1-3a forms a concave-convex structure by setting straight grooves 1-1-3a-1, which increases the contact area between the melt and the screw 1-1. This increases the friction between the melt and the screw 1-1, increases the screw 1-1's ability to transport the melt, and makes the melt move more easily between the screw 1-1 and the sleeve 1-2. This is equivalent to increasing the melt's moving speed, which can reduce the energy loss of the melt in the first metering section 1-1-3a. The result is a reduction in the melt's shear heat.

[0040] In summary, the first metering section 1-1-3a, by setting a straight groove 1-1-3a-1, exerts a smaller shear force on the melt and creates a greater mixing effect, which makes the melt temperature more uniform and the melt after passing through the compression section 1-1-2 has higher uniformity, ultimately improving the spinning quality, including increasing the fiber bundle strength, reducing the breakage rate, and increasing the full roll rate.

[0041] After passing through the first metering section 1-1-3a, the melt enters the second metering section 1-1-3b region. The second metering section 1-1-3b is relatively long and is arranged with equidistant threads. After passing through the second metering section 1-1-3b, the melt enters the third metering section 1-1-3c region. The third metering section 1-1-3c is equipped with splines. One possible implementation of the splines is as follows: Figure 3 As shown, numerous rhomboid blocks are evenly arranged around the perimeter. The melt, after being broken up by splines, enters the conical torpedo head 1-1-3d. The function of the conical torpedo head 1-1-3d is to form a shape similar to the surrounding area. Figure 5 The channel shown has a gradually decreasing cross-sectional area, which allows the melt to flow smoothly into the melt delivery pipe connected to the screw extruder outlet after passing through the conical torpedo head 1-1-3d. The conical torpedo head 1-1-3d also acts as a guide for the melt.

[0042] From an overall perspective, the four metering sections 1-1-3 described above are designed so that when the melt enters the metering section 1-1-3 from the compression section 1-1-2, the melt mixes and changes its direction of movement in the first metering section 1-1-3a, improving the mixing effect and making the melt more molten. When the melt enters the second metering section 1-1-3b from the first metering section 1-1-3a, the direction of melt movement changes again, improving the mixing effect and achieving a fully melted effect, while reducing shear heat due to the change in flow direction. When the melt enters the third metering section 1-1-3c from the second metering section 1-1-3b, the spline of the melt movement changes again, improving the mixing effect and achieving a fully melted effect, while reducing shear heat due to the change in flow direction. Finally, the melt is smoothly introduced into the melt conveying pipeline through the conical torpedo head 1-1-3d.

[0043] By changing the direction of melt movement three times as described above, the melt is fully mixed, resulting in more complete melting and further reduction of shear heat. Combined with the straight groove 1-1-3a-1 design of the first metering section 1-1-3a, shear heat and shear speed are also reduced, making it easier for the melt to move forward in the screw extruder. This allows for a longer screw design for the screw 1-1 of the screw extruder, enabling various polyester materials such as PET, PBT, and PTT to be heated, melted, compressed, and mixed over a longer process. This not only improves spinning quality but also allows the same screw extruder to be used for the production of various polyester fibers, providing a foundation for producing multiple polyester fibers with a single device.

[0044] In a preferred implementation scheme, such as Figure 3 As shown, a large number of straight grooves 1-1-3a-1 are provided at the bottom of the screw groove in the first metering section 1-1-3a, and these straight grooves 1-1-3a-1 are arranged at even intervals on the bottom of the groove. The length of the straight grooves 1-1-3a-1 is further limited, with both ends of their length extending to the screw ridge of the first metering section 1-1-3a. That is, the groove walls at both ends of the length of the straight grooves 1-1-3a-1 are located on the screw ridge of the first metering section 1-1-3a, so as to maximize the effect of the straight grooves 1-1-3a-1.

[0045] The length-to-diameter ratio of the screw in a typical polyester extrusion press is 25:1. Optionally, the screw extrusion press of this embodiment is used for the production of polyester fine denier industrial filaments, and the length-to-diameter ratio L / D of the screw 1-1 is controlled between 26:1 and 30:1, so as to relatively increase the length of the screw 1-1 and achieve the purpose of using the same screw extrusion press for the production of various polyester yarns.

[0046] With the increase in length-to-diameter ratio, the metering section 1-1-3 of screw 1-1 is correspondingly lengthened, reducing backflow and leakage, thus increasing the extrusion volume. Simultaneously, the increased residence time of the polyester material within the screw channel of screw 1-1 enhances its plasticizing capacity, allowing for an appropriate increase in the screw speed of screw 1-1, thereby improving the production capacity of the screw extruder. Furthermore, the uniform melting of the polyester material results in good plasticizing quality, reducing the root causes of fluctuations.

[0047] The inventors further limited the compression ratio of screw 1-1, controlling it between 2.19 and 2.5. This ensures the removal of gas from the material, which is beneficial for uniformity. On the other hand, it can improve the blockage problem that may be caused by solid materials, improve the defect of pressure fluctuation, and have a sufficient screw diameter in the feeding section area to ensure the screw strength in the feeding section area.

[0048] In a preferred embodiment, L = 28D, the length of the feeding section 1-1-1 is 9D, the length of the compression section 1-1-2 is 5D, the length of the first metering section 1-1-3a is 3D, the length of the second metering section 1-1-3b is 7D, the length of the third metering section 1-1-3c is 3D, and the length of the conical torpedo head 1-1-3d is 1D.

[0049] Using the same length-to-diameter ratio and compression ratio, screw 1-1 employs different die head pressures and temperature settings for different polyester chips, such as PET, PBT, and PTT, to ensure that the different polyester chips melt uniformly and prepare the melt for the next stage.

[0050] The heating zone of screw 1-1 is divided into 6 zones along the axial direction, namely zone 1-1-4a, zone 1-1-4b, zone 1-1-4c, zone 1-1-4d, zone 1-1-4e, and zone 1-1-4f, as follows: Figure 4 As shown, the first zone 1-1-4a and the second zone 1-1-4b together correspond to the feeding section 1-1-1, the third zone 1-1-4c corresponds to the compression section 1-1-2, and the fourth zone 1-1-4d, the fifth zone 1-1-4e, and the sixth zone 1-1-4f together correspond to the metering section 1-1-3. Furthermore, the lengths of the first zone 1-1-4a and the second zone 1-1-4b are equal, and the lengths of the fourth zone 1-1-4d, the fifth zone 1-1-4e, and the sixth zone 1-1-4f are equal.

[0051] When using PET chips to spin polyester fine denier industrial filaments: the chip viscosity is 0.95-1.05, preferably 0.98; the screw 1-1 compression ratio is 2.19-2.5, preferably 2.21; the screw 1-1 length-to-diameter ratio is 26:1-30:1, preferably 28:1; the set temperature for zone 1-1-4a is 285℃, the set temperature for zone 1-1-4b is 292℃, the set temperature for zone 1-1-4c is 295℃, the set temperature for zone 1-1-4d is 295℃, the set temperature for zone 1-1-4e is 291℃, and the set temperature for zone 1-1-4f is 287℃; the die pressure of the screw extruder is 12MPa.

[0052] When using PBT chips to spin polyester fine denier industrial filaments, the chip viscosity is 0.95-1.05, preferably 0.95; the screw compression ratio is 2.19-2.5, preferably 2.21; the screw length-to-diameter ratio is 25:1-30:1, preferably 28:1; the set temperature for zone 1-1-4a is 280℃, for zone 2-1-4b it is 295℃, for zone 3-1-4c it is 292℃, for zone 4-1-4d it is 290℃, for zone 5-1-4e it is 290℃, and for zone 6-1-4f it is 285℃; the die pressure of the screw extruder is 10MPa.

[0053] When using PTT chips to spin polyester fine denier industrial filaments, the chip viscosity is 0.95-1.05, preferably 1.0; the screw 1-1 compression ratio is 2.19-2.5, preferably 2.21; the screw 1-1 length-to-diameter ratio is 25:1-30:1, preferably 28:1; the set temperature for zone 1-1-4a is 285℃, for zone 2-1-4b it is 290℃, for zone 3-1-4c it is 296℃, for zone 4-1-4d it is 296℃, for zone 5-1-4e it is 293℃, and for zone 6-1-4f it is 288℃; the die pressure of the screw extruder is 11MPa.

[0054] Please refer to Figure 1 The screw extruder also includes: a screw extruder insulation cover 1-10 covering the heating coil 1-3, a screw extruder frame 1-9 serving as the mounting base, a screw extruder drive unit 1-5 for driving, a hopper 1-7 serving as the feed inlet, a temperature measuring element 1-4 for temperature measurement, and a pressure measuring element 1-11 for pressure measurement.

[0055] The screw extruder also includes the following: the screw extruder frame 1-9 is fixedly connected to the screw extruder insulation cover 1-10; the screw extruder drive unit 1-5 is drivenly connected to the screw 1-1; the screw extruder drive unit 1-5 is connected to the screw extruder frame 1-9; the temperature measuring element 1-4 is connected to the screw sleeve 1-2; the hopper 1-7 is connected to the screw sleeve 1-2 through the material cooling unit 1-6; and the hopper 1-7 is also provided with a nitrogen inlet 1-8.

[0056] Pressure measuring element 1-11 is used to measure the melt pressure at the outlet of the screw extruder. The measured melt pressure is used to regulate the screw 1-1. Specifically, this relates to the control principle of the screw extruder. The melt pressure is converted into a pressure signal by pressure measuring element 1-11. The pressure signal is sent to the transmitter and converted into a standard electrical signal. The regulating instrument that obtains this electrical signal outputs a regulating signal. The regulating signal is output as a speed signal via the frequency converter. This speed signal regulates the screw extruder drive component 1-5 to achieve the purpose of controlling the melt pressure. This cycle forms a closed-loop control system.

[0057] This embodiment also provides a spinning, drawing, and winding combined machine, including the aforementioned screw extruder, for the production of various polyester fine denier industrial filaments. Ultimately, it can simplify several existing production lines, reduce the equipment required by manufacturers, and reduce the area occupied in the factory, thereby reducing the cost of filament production and increasing the competitiveness of enterprises.

[0058] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0059] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A screw extruder, characterized in that, The screw of the screw extruder includes a feeding section, a compression section, and a metering section connected in sequence. The metering section includes a first metering section, a second metering section, a third metering section, and a conical torpedo head connected in sequence. The first metering section is connected to the compression section. The first metering section includes screw ridges, and screw grooves are formed between the screw ridges. Several straight grooves are opened at the bottom of the screw grooves of the first metering section. The length direction of the straight grooves is the same as the axial direction of the screw. The groove walls at both ends of the length of the straight grooves are located on the screw ridges of the first metering section. The second metering section is arranged with equidistant threads. The periphery of the third metering section is evenly arranged with diamond blocks to form splines. The screw extruder also includes a screw extruder drive unit and a pressure measuring element. The screw extruder drive unit is connected to the screw, and the pressure measuring element is used to measure the melt pressure at the outlet of the screw extruder. The melt pressure is used to regulate the screw extruder drive unit. The screw extruder is used for the production of polyester fine denier industrial filaments. The length-to-diameter ratio (L / D) of the screw is controlled between 26:1 and 30:1, and the compression ratio of the screw is controlled between 2.19 and 2.

5. The heating zone of the screw is divided into 6 zones along the axial direction. The first and second zones correspond to the feeding section, the third zone corresponds to the compression section, and the fourth, fifth, and sixth zones correspond to the metering section. When PET chips are used to spin polyester fine denier industrial filaments, the heating temperatures of the first zone to the sixth zone are 285°C, 292°C, 295°C, 295°C, 291°C and 287°C respectively, and the die pressure of the screw extruder is 12MPa. When using PBT chips to spin polyester fine denier industrial filaments, the heating temperatures of the first zone to the sixth zone are 280℃, 295℃, 292℃, 290℃, 290℃ and 285℃ respectively, and the die head pressure of the screw extruder is 10MPa. When using PTT chips to spin polyester fine denier industrial filaments, the heating temperatures of the first zone to the sixth zone are 285℃, 290℃, 296℃, 296℃, 293℃ and 288℃ respectively, and the die head pressure of the screw extruder is 11MPa.

2. The screw extruder as described in claim 1, characterized in that, The bottom of the screw groove in the first metering section is arranged with multiple straight grooves at even intervals.

3. The screw extruder as described in claim 1, characterized in that, L=28D, the length of the feeding section is 9D, the length of the compression section is 5D, the length of the first metering section is 3D, the length of the second metering section is 7D, the length of the third metering section is 3D, and the length of the conical torpedo head is 1D.

4. The screw extruder as described in any one of claims 1-3, characterized in that, The compression ratio of the screw is 2.

21.

5. The screw extruder as described in any one of claims 1, characterized in that, The viscosity of chips used for spinning polyester fine denier industrial filaments is controlled between 0.95 and 1.

05.

6. A spinning, drawing, and winding combined machine, characterized in that, The screw extruder as described in any one of claims 1-5 is used for the production of various polyester fine denier industrial filaments.

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