Production device and production method for sub-head spinning polyester pre-oriented yarn

Abstract

The invention belongs to the technical field of synthetic fibers, and relates to a production device and a production method of a head spinning polyester pre-oriented yarn. The production device comprises a sand cup, a first splitter plate, a second splitter plate and a spinneret plate which are sequentially arranged from top to bottom. The first splitter plate is provided with two first splitter holes which are symmetrically distributed, and the two first splitter holes are marked as a first splitter hole a'and a first splitter hole b 'respectively; two independent semi-cylindrical cavities are defined by the first splitter plate and the second splitter plate; and the second splitter plate and the spinneret plate jointly define two independent semi-cylindrical cavities. According to the production method, the production device is adopted, and the extrusion pressure of the first flow dividing hole a'and the first flow dividing hole b 'reaches 9-10 MPa in the spinning process. According to the production device, the deviation of the bus density of two bundles of filaments discharged from the same spinneret plate can be smaller than 1%. The preparation method is simple, low in cost, beneficial to improving the spinning efficiency and suitable for large-scale industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic fibers, and in particular relates to a production device and a production method for sub-spun polyester pre-oriented yarns. Background Art

[0002] The traditional production method of polyester pre-oriented yarn adopts the "one plate one cake" model, that is, one spinneret only spins one bundle of yarn. This model ensures the high quality of the yarn bundle, but has the disadvantage of low output. At the same time, when many chemical fiber production enterprises are built, the load, plate diameter and other parameters of each spinning line have been determined. If the output is to be increased, it is usually necessary to replace the entire system from the melt pipe to the winding equipment, which undoubtedly increases the high cost.

[0003] In order to increase the output, the prior art has modified the spinneret, dividing a spinneret into two for producing two bundles of yarn, thereby obtaining sub-head spun polyester pre-oriented yarn. The production process of sub-head spun polyester pre-oriented yarn includes the polyester melt passing through the sand cup of the spinning assembly, flowing out from the small hole at the bottom of the sand cup, flowing to the spinneret, and then spraying out from the spinneret hole. After the ejected yarn is divided into two bundles, it is oiled, guided and wound into a yarn cake. For example, patent application CN109825886A discloses a method for energy-saving and efficiency-enhancing winding equipment split plate transformation, which reconfigures the spinneret and replaces it with a spinneret in the form of XF*2, that is, the number of spinneret holes on the original spinneret is doubled (that is, the original XF is improved to XF*2), and these spinneret holes are spaced apart on both sides.

[0004] However, this transformation method also brings new problems. Since the flow rate of the melt in the filter sand is uneven, and as the use time of the spinning assembly increases, this unevenness will be aggravated, resulting in uneven distribution of the melt on the spinneret. Therefore, there are differences in the amount of wire output from each outlet hole, and this difference is random and irregular. This ultimately leads to a deviation in the total density of the two bundles of wire produced by the same spinneret. According to the industry standard for polyester pre-oriented yarn (FZ / T 54033-2012), the linear density deviation rate of conventional polyester pre-oriented yarn is ±2.0%, while the linear density deviation rate of sub-spun polyester pre-oriented yarn is relaxed to ±2.5%. However, with the increasing requirements of downstream weaving users for the linear density deviation rate between single yarns, the existing sub-spun polyester pre-oriented yarn can no longer meet market demand.

[0005] Therefore, it is particularly important to develop a production device and a production method for sub-spinning polyester pre-oriented yarns that can reduce the density deviation rate of two bundles of yarns produced by the same spinneret. Summary of the invention

[0006] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a production device and a production method for sub-spun polyester pre-oriented yarns.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A production device for sub-spinning polyester pre-oriented yarns, comprising a sand cup and a spinneret, wherein the spinneret holes on the spinneret are symmetrically distributed in two semicircular areas, the two semicircular areas are respectively marked as semicircular area a and semicircular area b, and further comprising a first splitter plate and a second splitter plate;

[0009] The sand cup, the first diverter plate, the second diverter plate, and the spinneret are arranged in order from top to bottom; the sand cup and the first diverter plate together form an inverted cone cavity, and the inverted cone cavity is coaxial with the sand cup; the first diverter plate and the second diverter plate together form two independent semi-cylindrical cavities, which are respectively recorded as semi-cylindrical cavity a* and semi-cylindrical cavity b*; the second diverter plate and the spinneret together form two independent semi-cylindrical cavities, which are respectively recorded as semi-cylindrical cavity a# and semi-cylindrical cavity b#;

[0010] The orthographic projections of the semi-cylindrical cavity a*, the semi-cylindrical cavity a# and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b*, the semi-cylindrical cavity b# and the semi-circular area b completely overlap;

[0011] The first diverter plate is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity, respectively denoted as the first diverter hole a' and the first diverter hole b', the first diverter hole a' connects the inverted conical cavity and the semi-cylindrical cavity a*, and the first diverter hole b' connects the inverted conical cavity and the semi-cylindrical cavity b*;

[0012] The outlet areas of the first diverter hole a' and the first diverter hole b' are the same, denoted as S1, and the sum of the outlet areas of all the spinneret holes is denoted as S2, S2×60%≤S1≤S2×90%, so that the extrusion pressure of the first diverter hole a' and the first diverter hole b' can be ensured to be greater than the extrusion pressure of the spinneret hole, and the flow rate of the melt entering the first diverter hole a' and the first diverter hole b' can be ensured to be consistent;

[0013] The second diverter plate is provided with two groups of second diverter holes which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b;

[0014] After the melt flows out of the sand cup, it enters the inverted cone cavity, and after being evenly diverted by the first diverter hole a' and the first diverter hole b', it reaches the semi-cylindrical cavity a* and the semi-cylindrical cavity b* respectively, and then passes through the second diverter hole to reach the semi-cylindrical cavity a# and the semi-cylindrical cavity b# respectively, and then is ejected from the spinneret hole. Among them, the purpose of designing the second diverter hole on the second diverter plate is to disperse and guide the melt coming out of the first diverter hole of the first diverter plate. After dispersion and guidance, the melt can evenly reach each spinneret hole of the spinneret plate, so as to avoid the consequence of uneven filament output from each spinneret hole. If there is no second diverter plate, although the total density of the two bundles of filaments coming out of the spinneret is uniform, the single filaments therein will be uneven.

[0015] As the preferred technical solution:

[0016] In the production device for sub-head spinning polyester pre-oriented yarn as described above, the sand cup is cylindrical, the first diverter plate, the second diverter plate and the spinneret are all circular plates, the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret, and the sand cup, the first diverter plate, the second diverter plate and the spinneret are coaxial.

[0017] In a production device for sub-spinning polyester pre-oriented yarn as described above, a melt distribution device is provided inside the sand cup, and the melt distribution device is used to change the flow direction of the melt entering the sand cup so that the melts in different areas are mixed with each other; the melt distribution device consists of a frustum and three blades installed on the frustum, the frustum is coaxial with the sand cup and the diameter of the large end face is smaller than the inner diameter of the sand cup, the large end face of the frustum is located below the small end face, the frustum is divided into two sections, upper and lower sections, and the three blades are all located in the upper section of the frustum.

[0018] In the production device of the polyester pre-oriented yarn spun by a sub-head spinning method, the outer diameter of the sand cup is 104-120 mm, the inner diameter is 96-112 mm, and the height is 69-70 mm; a plurality of through holes are opened at the bottom of the sand cup, all of which are distributed in concentric circles, the concentric circles are composed of 5-6 circles, the aperture of the through hole is 1.5-2 mm, and the distance between two adjacent through holes is 4-6 mm;

[0019] The diameter of the small end face of the truncated cone is 8-10mm, the diameter of the large end face is 18-20mm, the height is 30-32mm, and the distance between the truncated cone and the bottom of the sand cup is 2.5-3mm;

[0020] The blades are inclined curved flat plates, the inner curved surface of the curved flat plates fits the circumferential surface of the truncated cone, and the projections of the inner curved surfaces of the three curved flat plates on the horizontal plane enclose a complete circle; the highest point of the inner curved surface of the curved flat plate is 8-10 mm away from the upper end of the truncated cone, and the lowest point is 18-20 mm away from the lower end of the truncated cone; the arc length of the inner curved surface of the curved flat plate is 10-12 mm, and the angle between the plane of the curved flat plate and the horizontal plane is 26-28°.

[0021] In the production device of the sub-head spun polyester pre-oriented yarn as described above, filter screen 1, filter screen 2, filter screen 3, support screen 1, support screen 2 and support screen 3 are also arranged inside the sand cup, filter screen 1 and filter screen 2 are both mounted on the lower section of the truncated cone body, filter screen 1 is located above filter screen 2, and the two are arranged at a distance; when the melt passes through the metal sand, uneven pressure is likely to occur, and after adding two layers of filter screens, the pressure will be more uniform; filter screen 3, support screen 1, support screen 2, and support screen 3 are arranged in sequence from top to bottom at the bottom of the sand cup, and the purpose of placing the three support screens is to prevent the high-pressure polyester melt from squeezing and deforming the filter screen when passing through the high-mesh filter screen, thereby affecting the filtering effect.

[0022] As described above, in a production device for sub-head spinning polyester pre-oriented yarn, the vertical distance between filter screen 2 and the large end face of the truncated cone is 10 mm, the spacing between filter screen 2 and filter screen 1 is 10 mm, the apertures of filter screens 1 and 2 are both 60 mesh, the aperture of filter screen 3 is 600-800 mesh, the aperture of support screen 1 is 50 mesh, the aperture of support screen 2 is 20 mesh, and the aperture of support screen 3 is 10 mesh.

[0023] In the production device of polyester pre-oriented yarn by sub-spinning as described above, the bottom surface of the sand cup is a plane m; the upper surface of the first diverter plate is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret is a plane n;

[0024] The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a*, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b*; the semicircular groove a3 and the plane m together form a semi-cylindrical cavity a#, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#;

[0025] The upper surface of the second splitter plate is pressurized and connected to the lower surface of the first splitter plate through an aluminum pad, and the lower surface of the second splitter plate is pressurized and connected to the spinneret through an aluminum pad.

[0026] As described above, in a production device for sub-head spinning polyester pre-oriented yarn, the inverted conical cavity is in the shape of an inverted truncated cone, the diameter of the large bottom surface is 104-120mm, the height is 15-18mm, the angle between the main line and the large bottom surface is 18-20°, the upper ends of the first diversion hole a' and the first diversion hole b' are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a* and the semi-cylindrical cavity b* is 2-4mm; the total number of the second diversion holes is 120-130, and the aperture is 1.4-1.6mm, which is conducive to further evenly distributing the pressure of the polyester melt; the height of the semi-cylindrical cavity a# and the semi-cylindrical cavity b# is 1.5-3mm.

[0027] The present invention also provides a method for producing sub-head spun polyester pre-oriented yarns, which adopts a sub-head spun polyester pre-oriented yarn production device as described in any of the above items. During the spinning process, the pump output, S1, and S2 are adjusted to make the extrusion pressure of the first diversion hole a' and the first diversion hole b' reach 9-10MPa; the melt passes through the sand cup and flows into the inverted cone cavity between the sand cup and the first diversion plate, and then is extruded from the first diversion hole a' and the first diversion hole b'. During this process, the inverted cone cavity between the sand cup and the first diversion plate will be filled with the melt. Due to continuous feeding and discharging, the outlet area (S1) of the first diversion hole a' and the first diversion hole b' is small, resulting in a certain pressure of the melt in the inverted cone cavity, and this pressure is called extrusion pressure.

[0028] As the preferred technical solution:

[0029] In the production method of sub-head spinning polyester pre-oriented yarn as described above, the linear density deviation rate of two bundles of yarn coming out of the same spinneret is less than 1.0%, the linear density variation coefficient CV value of the two bundles of yarn is less than 0.6%, the yarn unevenness rate of each bundle of yarn is less than 1.4%, and the diameter deviation rate of any two monofilaments coming out of the same spinneret is less than 15%.

[0030] Beneficial effects:

[0031] (1) The preparation method of the present invention cleverly utilizes the first diverter plate to evenly divide the melt into two parts, and then introduces them into two completely independent chambers. This design significantly improves the uniformity of the flow and pressure of the two diverter holes on the first diverter plate. Then, the melt flowing out of the diverter holes of the first diverter plate is further dispersed and guided through a plurality of small holes densely distributed on the second diverter plate, ensuring that the melt can reach each spinneret hole of the spinneret plate evenly and stably. This process makes the melt pressure and the output of each spinneret hole more uniform and consistent, and finally achieves the excellent effect that the density deviation rate of the two bundles of silk produced by the same spinneret is less than 1.0%.

[0032] (2) The preparation method of the present invention does not require large-scale modification of the melt pipeline and winding equipment. It only requires the addition of a first wire dividing plate and a second wire dividing plate between the existing sand cup and the spinneret. The operation is simple and the cost is low. It is conducive to increasing the spinning output and is suitable for large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of a production device for sub-spun polyester pre-oriented yarns according to Examples 1-4 of the present invention;

[0034] Figure 2 yes Figure 1 A schematic diagram of the top view structure of the first manifold;

[0035] Figure 3 yes Figure 1 A schematic diagram of the structure of the first manifold plate viewed from above;

[0036] Figure 4 yes Figure 3 The schematic cross-sectional structure diagram of the first splitter plate along BB is shown;

[0037] Figure 5 yes Figure 1 A schematic diagram of the top view structure of the second diverter plate;

[0038] Figure 6 yes Figure 1 A schematic diagram of the structure of the second diverter plate viewed from above;

[0039] Figure 7 yes Figure 6 The schematic cross-sectional structure diagram of the second splitter plate along AA is shown;

[0040] Figure 8 It is a schematic structural diagram of a melt uniform distribution device according to Embodiment 5-7 of the present invention;

[0041] Fig. 9 Schematic diagram of the structure of the filter screen and the support screen of Embodiments 8-10 of the present invention;

[0042] Among them, 1 is a sand cup, 2 is a first diverter plate, 3 is a second diverter plate, 4 is a spinneret, 5 is metal sand, 6 is a truncated cone, 7 is a filter screen 1, 8 is a filter screen 2, 9 is a first diverter hole a', 10 is a first diverter hole b', 11 is a second diverter hole, 12 is a filter screen 3, 13 is a support screen 1, 14 is a support screen 2, 15 is a support screen 3, 16 is an inverted cone cavity, 17 is a semi-cylindrical cavity a*, 18 is a semi-cylindrical cavity b*, 19 is a semi-cylindrical cavity a#, 20 is a semi-cylindrical cavity b#, 21 is a first blade, and 22 is a second blade. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0044] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0045] (1) Deviation rate of linear density of two bundles of yarns and coefficient of variation of linear density of two bundles of yarns (CV): The two bundles of yarns from the same spinneret were recorded as yarn 1 and yarn 2 respectively. According to GB / T 14343-2008 “Test method for linear density of chemical fiber filaments”, the mass of 10,000 m sample was measured, and the linear density (dtex) of yarn 1 and the linear density (dtex) of yarn 2 were calculated. The deviation rate of linear density of two bundles of yarns was calculated according to the formula “deviation rate of linear density of two bundles of yarns = |linear density of yarn 1 - linear density of yarn 2| / linear density of yarn 1 × 100%”, and the coefficient of variation of linear density of two bundles of yarns (CV) was calculated according to the formula “standard deviation of linear density / average linear density”.

[0046] (2) The unevenness of the yarn strands of each bundle: According to GB / T 14346-2015 "Test method for unevenness of chemical filament yarn strands - Capacitance method", the test was carried out using USTER5 yarn strand uniformity meter. The specific process is as follows: first, the yarn strands are placed in an environment with a temperature of (20±2)°C and a relative humidity of (65±5)% for 2 h, and then the yarn strands are passed through the two electrodes of the capacitor at a uniform speed, and the mass in each equal interval is converted into an electrical signal. The percentage of the standard deviation of all test electrical signals to the average value is the unevenness of the yarn strands; the test speed is 200 m / min, and the yarn strand test time is 2.5 min.

[0047] (3) Diameter deviation rate of any two monofilaments: According to FZ / T 50002-2013 “Test method for profile of chemical fibers”, magnify the fiber cross section, measure the diameter of each monofilament, and calculate the diameter deviation rate of any two monofilaments according to the formula “diameter deviation rate of two monofilaments = |diameter of monofilament 1 - diameter of monofilament 2| / diameter of monofilament 1 × 100%”.

[0048] Example 1

[0049] like Figure 1The production device of a sub-head spinning polyester pre-oriented yarn shown in the figure is composed of a sand cup 1, a first diverter plate 2, a second diverter plate 3, a spinneret 4 and metal sand 5; the sand cup 1, the first diverter plate 2, the second diverter plate 3 and the spinneret 4 are arranged in sequence from top to bottom; the upper surface of the second diverter plate 3 is pressurized and connected to the lower surface of the first diverter plate 2 through an aluminum pad, and the lower surface of the second diverter plate 3 is pressurized and connected to the spinneret 4 through an aluminum pad;

[0050] The sand cup 1 is cylindrical, and the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are all circular plates; the sand cup 1, the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are coaxial;

[0051] The bottom surface of the sand cup 1 is a plane m; the upper surface of the first diverter plate 2 is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate 3 is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret 4 is a plane n;

[0052] The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity 16, and the inverted cone cavity 16 is coaxial with the sand cup 1; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a* 17, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b* 18; the semi-circular groove a3 and the plane m together form a semi-cylindrical cavity a# 19, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#20;

[0053] The spinneret holes on the spinneret 4 are circular and symmetrically distributed in two semicircular areas, which are respectively denoted as semicircular area a and semicircular area b; the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret 4;

[0054] The orthographic projections of the semi-cylindrical cavity a* 17, the semi-cylindrical cavity a# 19 and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b* 18, the semi-cylindrical cavity b# 20 and the semi-circular area b completely overlap;

[0055] like Figure 1-4 The first diverter plate 2 shown in the figure is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity 16, which are respectively denoted as the first diverter hole a'9 and the first diverter hole b'10. The first diverter hole a'9 connects the inverted conical cavity 16 and the semi-cylindrical cavity a*17, and the first diverter hole b'10 connects the inverted conical cavity 16 and the semi-cylindrical cavity b*18. The outlet areas of the first diverter hole a'9 and the first diverter hole b'10 are the same, denoted as S1, and the area of ​​S1 is 6.3 mm2 The sum of the outlet areas of all spinnerets is recorded as S2, and the area of ​​S2 is 10.5 mm 2 , S1 and S2 satisfy S1=S2×60%;

[0056] The outer diameter of the sand cup 1 is 104mm, the inner diameter is 96mm, and the height is 69mm; a plurality of through holes are provided at the bottom of the sand cup 1, all of which are distributed in concentric circles, the concentric circles are composed of 5 circles, the aperture of the through hole is 1.5mm, and the distance between two adjacent through holes is 4mm; the inverted conical cavity 16 is in the shape of an inverted truncated cone, the diameter of the large bottom surface is 104mm, the height is 15mm, the angle between the generatrix and the large bottom surface is 18°, the upper ends of the first diverter hole a'9 and the first diverter hole b'10 are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a*17 and the semi-cylindrical cavity b*18 is 2mm; the height of the semi-cylindrical cavity a#19 and the semi-cylindrical cavity b#20 is 1.5mm;

[0057] like Figure 5-7 The second diverter plate 3 shown is provided with two groups of second diverter holes 11 which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b; the total number of the second diverter holes 11 is 120, and the hole diameter is 1.6 mm.

[0058] A method for producing sub-spinning polyester pre-oriented yarns, using the above-mentioned sub-spinning polyester pre-oriented yarn production device, adjusting the pumping rate to 106g / min during the spinning process, so that the extrusion pressure of the first diverter hole a'9 and the first diverter hole b'10 reaches 10MPa. The linear density deviation rate of two bundles of yarns from the same spinneret is 0.7%, the linear density variation coefficient CV value of the two bundles of yarns is 0.29%, the maximum unevenness rate of each bundle of yarns is 1.33%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 13.5%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0059] Example 2

[0060] like Figure 1 The production device of a sub-head spinning polyester pre-oriented yarn shown in the figure is composed of a sand cup 1, a first diverter plate 2, a second diverter plate 3, a spinneret 4 and metal sand 5; the sand cup 1, the first diverter plate 2, the second diverter plate 3 and the spinneret 4 are arranged in sequence from top to bottom; the upper surface of the second diverter plate 3 is pressurized and connected to the lower surface of the first diverter plate 2 through an aluminum pad, and the lower surface of the second diverter plate 3 is pressurized and connected to the spinneret 4 through an aluminum pad;

[0061] The sand cup 1 is cylindrical, and the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are all circular plates; the sand cup 1, the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are coaxial;

[0062] The bottom surface of the sand cup 1 is a plane m; the upper surface of the first diverter plate 2 is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate 3 is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret 4 is a plane n;

[0063] The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity 16, and the inverted cone cavity 16 is coaxial with the sand cup 1; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a* 17, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b* 18; the semi-circular groove a3 and the plane m together form a semi-cylindrical cavity a# 19, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#20;

[0064] The spinneret holes on the spinneret 4 are circular and symmetrically distributed in two semicircular areas, which are respectively denoted as semicircular area a and semicircular area b; the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret 4;

[0065] The orthographic projections of the semi-cylindrical cavity a* 17, the semi-cylindrical cavity a# 19 and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b* 18, the semi-cylindrical cavity b# 20 and the semi-circular area b completely overlap;

[0066] like Figure 1-4 The first diverter plate 2 shown in the figure is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity 16, which are respectively denoted as the first diverter hole a'9 and the first diverter hole b'10. The first diverter hole a'9 connects the inverted conical cavity 16 and the semi-cylindrical cavity a*17, and the first diverter hole b'10 connects the inverted conical cavity 16 and the semi-cylindrical cavity b*18. The outlet areas of the first diverter hole a'9 and the first diverter hole b'10 are the same, denoted as S1, and the area of ​​S1 is 6.16 mm 2 The sum of the outlet areas of all spinnerets is recorded as S2, and the area of ​​S2 is 8.8mm 2 , S1 and S2 satisfy S1=S2×70%;

[0067] The outer diameter of the sand cup 1 is 105mm, the inner diameter is 97mm, and the height is 69.5mm; a plurality of through holes are provided at the bottom of the sand cup 1, all of which are distributed in concentric circles, the concentric circles are composed of 6 circles, the aperture of the through hole is 1.8mm, and the distance between two adjacent through holes is 5mm; the inverted conical cavity 16 is in the shape of an inverted truncated cone, the diameter of the large bottom surface is 105mm, the height is 15.5mm, the angle between the generatrix and the large bottom surface is 19°, and the upper ends of the first diverter hole a'9 and the first diverter hole b'10 are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a*17 and the semi-cylindrical cavity b*18 is 2.5mm; the height of the semi-cylindrical cavity a#19 and the semi-cylindrical cavity b#20 is 2mm;

[0068] like Figure 5-7 The second diverter plate 3 shown is provided with two groups of second diverter holes 11 which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b; the total number of the second diverter holes 11 is 123, and the hole diameter is 1.55 mm.

[0069] A method for producing sub-spinning polyester pre-oriented yarns, using the above-mentioned sub-spinning polyester pre-oriented yarn production device, adjusting the pumping rate to 98g / min during the spinning process, so that the extrusion pressure of the first diverter hole a'9 and the first diverter hole b'10 reaches 9.8MPa. The linear density deviation rate of two bundles of yarns from the same spinneret is 0.8%, the linear density variation coefficient CV value of the two bundles of yarns is 0.43%, the maximum unevenness rate of each bundle of yarns is 1.22%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 13.4%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0070] Example 3

[0071] like Figure 1 The production device of a sub-head spinning polyester pre-oriented yarn shown in the figure is composed of a sand cup 1, a first diverter plate 2, a second diverter plate 3, a spinneret 4 and metal sand 5; the sand cup 1, the first diverter plate 2, the second diverter plate 3 and the spinneret 4 are arranged in sequence from top to bottom; the upper surface of the second diverter plate 3 is pressurized and connected to the lower surface of the first diverter plate 2 through an aluminum pad, and the lower surface of the second diverter plate 3 is pressurized and connected to the spinneret 4 through an aluminum pad;

[0072] The sand cup 1 is cylindrical, and the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are all circular plates; the sand cup 1, the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are coaxial;

[0073] The bottom surface of the sand cup 1 is a plane m; the upper surface of the first diverter plate 2 is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate 3 is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret 4 is a plane n;

[0074] The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity 16, and the inverted cone cavity 16 is coaxial with the sand cup 1; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a* 17, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b* 18; the semi-circular groove a3 and the plane m together form a semi-cylindrical cavity a# 19, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#20;

[0075] The spinneret holes on the spinneret 4 are circular and symmetrically distributed in two semicircular areas, which are respectively denoted as semicircular area a and semicircular area b; the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret 4;

[0076] The orthographic projections of the semi-cylindrical cavity a* 17, the semi-cylindrical cavity a# 19 and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b* 18, the semi-cylindrical cavity b# 20 and the semi-circular area b completely overlap;

[0077] like Figure 1-4 The first diverter plate 2 shown in the figure is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity 16, which are respectively denoted as the first diverter hole a'9 and the first diverter hole b'10. The first diverter hole a'9 connects the inverted conical cavity 16 and the semi-cylindrical cavity a*17, and the first diverter hole b'10 connects the inverted conical cavity 16 and the semi-cylindrical cavity b*18. The outlet areas of the first diverter hole a'9 and the first diverter hole b'10 are the same, denoted as S1, and the area of ​​S1 is 5.52 mm 2 The sum of the outlet areas of all spinnerets is recorded as S2, and the area of ​​S2 is 6.9 mm 2 , S1 and S2 satisfy S1=S2×80%;

[0078] The outer diameter of the sand cup 1 is 120 mm, the inner diameter is 112 mm, and the height is 70 mm; a plurality of through holes are provided at the bottom of the sand cup 1, all of which are distributed in concentric circles, the concentric circles are composed of 5 circles, the aperture of the through hole is 2 mm, and the distance between two adjacent through holes is 6 mm; the inverted conical cavity 16 is in the shape of an inverted truncated cone, the diameter of the large bottom surface is 120 mm, the height is 18 mm, the angle between the generatrix and the large bottom surface is 20°, the upper ends of the first diverter hole a'9 and the first diverter hole b'10 are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a*17 and the semi-cylindrical cavity b*18 is 3 mm; the height of the semi-cylindrical cavity a#19 and the semi-cylindrical cavity b#20 is 2.5 mm;

[0079] like Figure 5-7 The second diverter plate 3 shown is provided with two groups of second diverter holes 11 which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b; the total number of the second diverter holes 11 is 125, and the hole diameter is 1.5 mm.

[0080] A method for producing sub-spinning polyester pre-oriented yarns, using the above-mentioned sub-spinning polyester pre-oriented yarn production device, adjusting the pumping rate to 90g / min during the spinning process, so that the extrusion pressure of the first diverter hole a'9 and the first diverter hole b'10 reaches 9.5MPa. The linear density deviation rate of two bundles of yarns from the same spinneret is 0.8%, the linear density variation coefficient CV value of the two bundles of yarns is 0.41%, the maximum unevenness rate of each bundle of yarns is 1.36%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 14.7%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0081] Example 4

[0082] like Figure 1 The production device of a sub-head spinning polyester pre-oriented yarn shown in the figure is composed of a sand cup 1, a first diverter plate 2, a second diverter plate 3, a spinneret 4 and metal sand 5; the sand cup 1, the first diverter plate 2, the second diverter plate 3 and the spinneret 4 are arranged in sequence from top to bottom; the upper surface of the second diverter plate 3 is pressurized and connected to the lower surface of the first diverter plate 2 through an aluminum pad, and the lower surface of the second diverter plate 3 is pressurized and connected to the spinneret 4 through an aluminum pad;

[0083] The sand cup 1 is cylindrical, and the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are all circular plates; the sand cup 1, the first splitter plate 2, the second splitter plate 3, and the spinneret plate 4 are coaxial;

[0084] The bottom surface of the sand cup 1 is a plane m; the upper surface of the first diverter plate 2 is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate 3 is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret 4 is a plane n;

[0085] The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity 16, and the inverted cone cavity 16 is coaxial with the sand cup 1; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a* 17, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b* 18; the semi-circular groove a3 and the plane m together form a semi-cylindrical cavity a# 19, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#20;

[0086] The spinneret holes on the spinneret 4 are circular and symmetrically distributed in two semicircular areas, which are respectively denoted as semicircular area a and semicircular area b; the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret 4;

[0087] The orthographic projections of the semi-cylindrical cavity a* 17, the semi-cylindrical cavity a# 19 and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b* 18, the semi-cylindrical cavity b# 20 and the semi-circular area b completely overlap;

[0088] like Figure 1-4 The first diverter plate 2 shown in the figure is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity 16, which are respectively denoted as the first diverter hole a'9 and the first diverter hole b'10. The first diverter hole a'9 connects the inverted conical cavity 16 and the semi-cylindrical cavity a*17, and the first diverter hole b'10 connects the inverted conical cavity 16 and the semi-cylindrical cavity b*18. The outlet areas of the first diverter hole a'9 and the first diverter hole b'10 are the same, denoted as S1, and the area of ​​S1 is 4.68 mm 2 The sum of the outlet areas of all spinnerets is recorded as S2, and the area of ​​S2 is 5.2 mm 2 , S1 and S2 satisfy S1=S2×90%;

[0089] The outer diameter of the sand cup 1 is 120 mm, the inner diameter is 112 mm, and the height is 70 mm; a plurality of through holes are provided at the bottom of the sand cup 1, all of which are distributed in concentric circles, the concentric circles are composed of 5 circles, the aperture of the through hole is 2 mm, and the distance between two adjacent through holes is 6 mm; the inverted conical cavity 16 is in the shape of an inverted truncated cone, the diameter of the large bottom surface is 120 mm, the height is 18 mm, the angle between the generatrix and the large bottom surface is 20°, the upper ends of the first diverter hole a'9 and the first diverter hole b'10 are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a*17 and the semi-cylindrical cavity b*18 is 4 mm; the height of the semi-cylindrical cavity a#19 and the semi-cylindrical cavity b#20 is 3 mm;

[0090] like Figure 5-7 The second diverter plate 3 shown is provided with two groups of second diverter holes 11 which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b; the total number of the second diverter holes 11 is 130, and the hole diameter is 1.4 mm.

[0091] A method for producing sub-spinning polyester pre-oriented yarns, using the above-mentioned sub-spinning polyester pre-oriented yarn production device, the pumping amount during the spinning process is 82g / min, so that the extrusion pressure of the first diverter hole a'9 and the first diverter hole b'10 reaches 9.0MPa. The linear density deviation rate of two bundles of yarns from the same spinneret is 0.9%, the linear density variation coefficient CV value of the two bundles of yarns is 0.55%, the maximum unevenness rate of each bundle of yarns is 1.29%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 14.1%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0092] Comparative Example 1

[0093] A production device for sub-spinning polyester pre-oriented yarn, which is basically the same as Example 1, except that: the S1 value is 6.3 mm 2 , S2 value is 15.75mm 2 , S1=S2×40%.

[0094] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the production device in Comparative Example 1 is used for spinning.

[0095] Since the ratio of S1 to S2 is too small, it is easy to cause excessive pressure on the components, resulting in 18 slurry leakage quality problems in 36 spinning positions within 24 hours.

[0096] Comparative Example 2

[0097] A production device for sub-spinning polyester pre-oriented yarn, which is basically the same as Example 1, except that: the S1 value is 6.3 mm 2 , S2 value is 12.6mm 2, S1=S2×50%.

[0098] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the production device of Comparative Example 2 is used for spinning.

[0099] Since the ratio of S1 to S2 is too small, it is easy to cause excessive pressure on the components, resulting in 15 leakage quality problems in 36 positions within 24 hours.

[0100] Comparative Example 3

[0101] A production device for sub-spinning polyester pre-oriented yarn, which is basically the same as Example 1, except that: the S1 value is 6.3 mm 2 , S2 value is 6.63mm 2 , S1=S2×95%.

[0102] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the production device of Comparative Example 3 is used for spinning.

[0103] The linear density deviation rate of two bundles of yarn coming out of the same spinneret is 1.1%, the linear density variation coefficient CV value of the two bundles of yarn is 0.81%, the maximum unevenness rate of each bundle of yarn is 1.57%, and the maximum diameter deviation rate of any two single yarns coming out of the same spinneret is 20.6%.

[0104] Comparative Example 4

[0105] A production device for sub-spinning polyester pre-oriented yarn, which is basically the same as Example 1, except that: the S1 value is 6.3 mm 2 , S2 is 6.3mm 2 , S1=S2×100%.

[0106] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the production device of Comparative Example 4 is used for spinning.

[0107] The linear density deviation rate of two bundles of yarn coming out of the same spinneret is 1.8%, the linear density variation coefficient CV value of the two bundles of yarn is 1.27%, the maximum unevenness rate of each bundle of yarn is 1.79%, and the maximum diameter deviation rate of any two single yarns coming out of the same spinneret is 30.1%.

[0108] Compared with Example 1, the linear density deviation rate of the two bundles of yarn coming out of the same spinneret in Comparative Examples 3 and 4, the linear density variation coefficient CV value of the two bundles of yarn, the yarn unevenness CV value of each bundle of yarn, and the diameter deviation rate of any two single yarns are significantly increased. This is because S1 and S2 are of the same size, and the first diversion hole a' and the first diversion hole b' fail to play a diversion role, which leads to an increase in deviation.

[0109] Comparing comparative examples 1-4 with embodiments 1-4, it can be seen that a ratio of S1 to S2 that is too large or too small is disadvantageous. When the ratio is too small, 36 spinning positions will experience multiple slurry leakage problems within 24 hours. When the ratio is too large, the linear density deviation rate of the two bundles of yarn increases, the linear density variation coefficient CV value of the two bundles of yarn increases, the unevenness of each bundle of yarn increases, and the diameter deviation rate of any two monofilaments from the same spinneret increases.

[0110] Example 5

[0111] A production device for sub-spinning polyester pre-oriented yarn, which is different from Example 1 in that: Figure 8 As shown, the sand cup 1 is further provided with a melt uniform distribution device, which is used to change the flow direction of the melt entering the sand cup 1 so that the melts in different areas are mixed with each other. The melt uniform distribution device is composed of a truncated cone body 6 and three blades installed on the truncated cone body 6. The three blades are a first blade 21, a second blade 22 and a third blade (the third blade is Figure 8 Not shown), the truncated cone body 6 is coaxial with the sand cup 1 and the diameter of the large end face is smaller than the inner diameter of the sand cup. The large end face of the truncated cone body 6 is located below the small end face. The truncated cone body 6 is divided into two sections, upper and lower. The three blades are all located in the upper section of the truncated cone body 6;

[0112] The small end face diameter of the truncated cone body 6 is 8 mm, the large end face diameter is 18 mm, the height is 30 mm, and the distance between the truncated cone body 6 and the bottom of the sand cup 1 is 2.5 mm;

[0113] The blades are inclined curved flat plates, the inner curved surface of the curved flat plates fits the circumferential surface of the truncated cone body 6, and the projections of the inner curved surfaces of the three curved flat plates on the horizontal plane enclose a complete circle; the highest point of the inner curved surface of the curved flat plate is 8 mm from the upper end of the truncated cone body 6, and the lowest point is 18 mm from the lower end of the truncated cone body 6; the arc length of the inner curved surface of the curved flat plate is 10 mm, and the angle between the plane of the curved flat plate and the horizontal plane is 26°.

[0114] A method for producing sub-spinning polyester pre-oriented yarn is basically the same as that of Example 1, except that the spinning is performed using the production device of Example 5. The linear density deviation rate of two yarn bundles from the same spinneret is 0.6%, the linear density variation coefficient CV value of the two yarn bundles is 0.21%, the maximum unevenness rate of each yarn bundle is 1.28%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 13.9%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0115] Example 6

[0116] A production device for sub-spinning polyester pre-oriented yarn, which is different from Example 1 in that: Figure 8As shown, the sand cup 1 is further provided with a melt uniform distribution device, which is used to change the flow direction of the melt entering the sand cup 1 so that the melts in different areas are mixed with each other. The melt uniform distribution device is composed of a truncated cone body 6 and three blades installed on the truncated cone body 6. The three blades are a first blade 21, a second blade 22 and a third blade (the third blade is Figure 8 Not shown), the truncated cone body 6 is coaxial with the sand cup 1 and the diameter of the large end face is smaller than the inner diameter of the sand cup. The large end face of the truncated cone body 6 is located below the small end face. The truncated cone body 6 is divided into two sections, upper and lower. The three blades are all located in the upper section of the truncated cone body 6;

[0117] The small end face diameter of the truncated cone body 6 is 9 mm, the large end face diameter is 19 mm, the height is 31 mm, and the distance between the truncated cone body 6 and the bottom of the sand cup 1 is 3 mm;

[0118] The blades are inclined curved flat plates, the inner curved surface of the curved flat plates fits the circumferential surface of the truncated cone body 6, and the projections of the inner curved surfaces of the three curved flat plates on the horizontal plane enclose a complete circle; the highest point of the inner curved surface of the curved flat plate is 10 mm away from the upper end of the truncated cone body 6, and the lowest point is 20 mm away from the lower end of the truncated cone body 6; the arc length of the inner curved surface of the curved flat plate is 11 mm, and the angle between the plane of the curved flat plate and the horizontal plane is 27°.

[0119] A method for producing sub-spinning polyester pre-oriented yarn is basically the same as that of Example 1, except that the spinning is performed using the production device of Example 6. The linear density deviation rate of two yarn bundles from the same spinneret is 0.6%, the linear density variation coefficient CV value of the two yarn bundles is 0.24%, the maximum unevenness rate of each yarn bundle is 1.17%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 12.5%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0120] Example 7

[0121] A production device for sub-spinning polyester pre-oriented yarn, which is different from Example 1 in that: Figure 8 As shown, the sand cup 1 is further provided with a melt uniform distribution device, which is used to change the flow direction of the melt entering the sand cup 1 so that the melts in different areas are mixed with each other. The melt uniform distribution device is composed of a truncated cone body 6 and three blades installed on the truncated cone body 6. The three blades are a first blade 21, a second blade 22 and a third blade (the third blade is Figure 8 Not shown), the truncated cone body 6 is coaxial with the sand cup 1 and the diameter of the large end face is smaller than the inner diameter of the sand cup. The large end face of the truncated cone body 6 is located below the small end face. The truncated cone body 6 is divided into two sections, upper and lower. The three blades are all located in the upper section of the truncated cone body 6;

[0122] The small end face diameter of the truncated cone body 6 is 10 mm, the large end face diameter is 20 mm, the height is 32 mm, and the distance between the truncated cone body 6 and the bottom of the sand cup 1 is 2.8 mm;

[0123] The blades are inclined curved flat plates, the inner curved surface of the curved flat plates fits the circumferential surface of the truncated cone body 6, and the projections of the inner curved surfaces of the three curved flat plates on the horizontal plane enclose a complete circle; the highest point of the inner curved surface of the curved flat plate is 9 mm from the upper end of the truncated cone body 6, and the lowest point is 19 mm from the lower end of the truncated cone body 6; the arc length of the inner curved surface of the curved flat plate is 12 mm, and the angle between the plane of the curved flat plate and the horizontal plane is 28°.

[0124] A method for producing sub-spinning polyester pre-oriented yarn is basically the same as that of Example 1, except that the spinning is performed using the production device of Example 7. The linear density deviation rate of two yarn bundles from the same spinneret is 0.6%, the linear density variation coefficient CV value of the two yarn bundles is 0.26%, the maximum unevenness rate of each yarn bundle is 1.27%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 12.7%, and there is no slurry leakage problem in 36 spinning positions for 24 hours.

[0125] In Examples 5-7, the linear density deviation rate of two bundles of yarn from the same spinneret is 0.6%, the linear density variation coefficient CV value of the two bundles of yarn is 0.21-0.26%, the maximum unevenness rate of each bundle of yarn is 1.17-1.28%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 12.5-13.9%, and there is no leakage problem in 36 spinning positions for 24 hours.

[0126] The unevenness of the strands of each filament coming out of the same spinneret in Examples 5-7 and Example 1 is less than 1.4%, and the diameter deviation rate of any two single filaments coming out of the same spinneret is less than 15%; however, the linear density deviation rate of the two filaments coming out of the same spinneret in Examples 5-7 is smaller, and the linear density variation coefficient CV value of the two filaments is also smaller, indicating that the provision of a melt distribution device inside the sand cup is beneficial to reducing the linear density deviation rate of the two filaments coming out of the same spinneret and the linear density variation coefficient CV value of the two filaments.

[0127] Example 8

[0128] A production device for sub-spinning polyester pre-oriented yarn, which differs from Example 5 in that: Fig. 9As shown, the inside of the sand cup 1 is also provided with a filter screen 1 7, a filter screen 2 8, a filter screen 3 12, a support screen 1 13, a support screen 2 14 and a support screen 3 15; the filter screen 1 7 and the filter screen 2 8 are both mounted on the lower section of the truncated cone body 6, the filter screen 1 7 is located above the filter screen 2 8, and the two are arranged at a distance; the filter screen 3 12, the support screen 1 13, the support screen 2 14, and the support screen 3 15 are arranged in sequence from top to bottom at the bottom of the sand cup 1; the vertical distance between the filter screen 2 8 and the large end surface of the truncated cone body 6 is 10 mm, the spacing between the filter screen 2 8 and the filter screen 1 7 is 10 mm, the apertures of the filter screen 1 7 and the filter screen 2 8 are both 60 meshes, the aperture of the filter screen 3 12 is 800 meshes, the aperture of the support screen 1 13 is 50 meshes, the aperture of the support screen 2 14 is 20 meshes, and the aperture of the support screen 3 15 is 10 meshes.

[0129] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the production device of Example 8 is used for spinning.

[0130] The linear density deviation rate of two bundles of yarn coming out of the same spinneret is 0.4%, the linear density variation coefficient CV value of the two bundles of yarn is 0.24%, the maximum unevenness rate of each bundle of yarn is CV value 1.14%, the maximum diameter deviation rate of any two single yarns coming out of the same spinneret is 12.6%, and there is no leakage problem in 36 spinning positions for 24 hours.

[0131] Example 9

[0132] A production device for sub-spinning polyester pre-oriented yarn, which differs from Example 5 in that: Fig. 9 As shown, the inside of the sand cup 1 is also provided with a filter screen 1 7, a filter screen 2 8, a filter screen 3 12, a support screen 1 13, a support screen 2 14 and a support screen 3 15; the filter screen 1 7 and the filter screen 2 8 are both mounted on the lower section of the truncated cone body 6, the filter screen 1 7 is located above the filter screen 2 8, and the two are arranged at a distance; the filter screen 3 12, the support screen 1 13, the support screen 2 14, and the support screen 3 15 are arranged in sequence from top to bottom at the bottom of the sand cup 1; the vertical distance between the filter screen 2 8 and the large end surface of the truncated cone body 6 is 10 mm, the spacing between the filter screen 2 8 and the filter screen 1 7 is 10 mm, the apertures of the filter screen 1 7 and the filter screen 2 8 are both 60 meshes, the aperture of the filter screen 3 12 is 700 meshes, the aperture of the support screen 1 13 is 50 meshes, the aperture of the support screen 2 14 is 20 meshes, and the aperture of the support screen 3 15 is 10 meshes.

[0133] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that in Example 1, except that the spinning is performed using the production device of Example 9.

[0134] The linear density deviation rate of two bundles of yarn coming out of the same spinneret is 0.5%, the linear density variation coefficient CV value of the two bundles of yarn is 0.19%, the maximum unevenness rate of each bundle of yarn is 1.23%, the maximum diameter deviation rate of any two single yarns coming out of the same spinneret is 11.8%, and there is no leakage problem in 36 spinning positions for 24 hours.

[0135] Example 10

[0136] A production device for sub-spinning polyester pre-oriented yarn, which differs from Example 5 in that: Fig. 9 As shown, the inside of the sand cup 1 is also provided with a filter screen 1 7, a filter screen 2 8, a filter screen 3 12, a support screen 1 13, a support screen 2 14 and a support screen 3 15; the filter screen 1 7 and the filter screen 2 8 are both mounted on the lower section of the truncated cone body 6, the filter screen 1 7 is located above the filter screen 2 8, and the two are arranged at a distance; the filter screen 3 12, the support screen 1 13, the support screen 2 14, and the support screen 3 15 are arranged in sequence from top to bottom at the bottom of the sand cup 1; the vertical distance between the filter screen 2 8 and the large end surface of the truncated cone body 6 is 10 mm, the spacing between the filter screen 2 8 and the filter screen 1 7 is 10 mm, the apertures of the filter screen 1 7 and the filter screen 2 8 are both 60 meshes, the aperture of the filter screen 3 12 is 600 meshes, the aperture of the support screen 1 13 is 50 meshes, the aperture of the support screen 2 14 is 20 meshes, and the aperture of the support screen 3 15 is 10 meshes.

[0137] A method for producing sub-spun polyester pre-oriented yarn is basically the same as that of Example 1, with the only difference being that the production device of Example 10 is used for spinning.

[0138] The linear density deviation rate of two bundles of yarn coming out of the same spinneret is 0.5%, the linear density variation coefficient CV value of the two bundles of yarn is 0.26%, the maximum unevenness rate of each bundle of yarn is 1.07%, the maximum diameter deviation rate of any two single yarns coming out of the same spinneret is 12.5%, and there is no leakage problem in 36 spinning positions for 24 hours.

[0139] In Examples 8-10, the linear density deviation rate of two bundles of yarn from the same spinneret is 0.4-0.5%, the linear density variation coefficient CV value of the two bundles of yarn is 0.19-0.26%, the maximum unevenness rate of each bundle of yarn is 1.07-1.23%, the maximum diameter deviation rate of any two monofilaments from the same spinneret is 11.8-12.6%, and there is no leakage problem in 36 spinning positions for 24 hours.

[0140] Comparing Examples 8-10 with Example 5, the unevenness of each bundle of yarn in Examples 8-10 and Example 5 is less than 1.4%, the diameter deviation rate of any two single yarns from the same spinneret is less than 15%, and the coefficient of variation CV value of the linear density of the two bundles of yarn is less than 0.6%; however, the linear density deviation rate of the two bundles of yarn from the same spinneret of Examples 8-10 is smaller, indicating that the three specific filter screens and three specific support screens inside the sand cup can further reduce the linear density deviation rate of the two bundles of yarn.

Claims

1. A production device for polyester pre-oriented yarn by sub-spinning, comprising a sand cup and a spinneret, wherein the spinneret holes on the spinneret are symmetrically distributed in two semicircular areas, the two semicircular areas are respectively marked as semicircular area a and semicircular area b, characterized in that: Also included is a first manifold and a second manifold; The sand cup, the first diverter plate, the second diverter plate, and the spinneret are arranged in order from top to bottom; the sand cup and the first diverter plate together form an inverted cone cavity, and the inverted cone cavity is coaxial with the sand cup; the first diverter plate and the second diverter plate together form two independent semi-cylindrical cavities, which are respectively recorded as semi-cylindrical cavity a* and semi-cylindrical cavity b*; the second diverter plate and the spinneret together form two independent semi-cylindrical cavities, which are respectively recorded as semi-cylindrical cavity a# and semi-cylindrical cavity b#; The orthographic projections of the semi-cylindrical cavity a*, the semi-cylindrical cavity a# and the semi-circular area a completely overlap; the orthographic projections of the semi-cylindrical cavity b*, the semi-cylindrical cavity b# and the semi-circular area b completely overlap; The first diverter plate is provided with two first diverter holes symmetrically distributed on both sides of the central axis of the inverted conical cavity, respectively denoted as the first diverter hole a' and the first diverter hole b', the first diverter hole a' connects the inverted conical cavity and the semi-cylindrical cavity a*, and the first diverter hole b' connects the inverted conical cavity and the semi-cylindrical cavity b*; The outlet areas of the first split hole a' and the first split hole b' are the same, denoted as S1, and the sum of the outlet areas of all spinnerets is denoted as S2, S2×60%≤S1≤S2×90%; The second flow dividing plate is provided with two groups of second flow dividing holes which are symmetrically distributed and respectively located above the semicircular area a and the semicircular area b.

2. The production device of sub-spinning polyester pre-oriented yarn according to claim 1, characterized in that: The sand cup is cylindrical, the first diverter plate, the second diverter plate and the spinneret plate are all circular plates, the symmetry axes of the semicircular area a and the semicircular area b intersect with the central axis of the spinneret plate, and the sand cup, the first diverter plate, the second diverter plate and the spinneret plate are coaxial.

3. The production device of sub-spinning polyester pre-oriented yarn according to claim 2, characterized in that: A melt distribution device is provided inside the sand cup, which is used to change the flow direction of the melt entering the sand cup so that the melts in different areas are mixed with each other; the melt distribution device consists of a frustum and three blades installed on the frustum. The frustum is coaxial with the sand cup and the diameter of the large end face is smaller than the inner diameter of the sand cup. The large end face of the frustum is located below the small end face. The frustum is divided into two sections, upper and lower sections, and the three blades are all located in the upper section of the frustum.

4. The production device of sub-spinning polyester pre-oriented yarn according to claim 3, characterized in that: The outer diameter of the sand cup is 104-120mm, the inner diameter is 96-112mm, and the height is 69-70mm. There are multiple through holes at the bottom of the sand cup, all of which are distributed in concentric circles, each of which is composed of 5-6 circles. The diameter of the through hole is 1.5-2mm, and the distance between two adjacent through holes is 4-6mm. The diameter of the small end face of the truncated cone is 8-10mm, the diameter of the large end face is 18-20mm, the height is 30-32mm, and the distance between the truncated cone and the bottom of the sand cup is 2.5-3mm; The blades are inclined curved flat plates, the inner curved surface of the curved flat plates fits the circumferential surface of the truncated cone, and the projections of the inner curved surfaces of the three curved flat plates on the horizontal plane enclose a complete circle; the highest point of the inner curved surface of the curved flat plate is 8-10 mm away from the upper end of the truncated cone, and the lowest point is 18-20 mm away from the lower end of the truncated cone; the arc length of the inner curved surface of the curved flat plate is 10-12 mm, and the angle between the plane of the curved flat plate and the horizontal plane is 26-28°.

5. The production device of sub-spinning polyester pre-oriented yarn according to claim 3, characterized in that: The sand cup is also provided with filter 1, filter 2, filter 3, support net 1, support net 2 and support net 3. Filter 1 and filter 2 are both mounted on the lower section of the truncated cone body, filter 1 is located above filter 2, and the two are arranged at a distance; filter 3, support net 1, support net 2 and support net 3 are arranged in sequence from top to bottom at the bottom of the sand cup.

6. The production device of sub-spun polyester pre-oriented yarn according to claim 5, characterized in that: The vertical distance between filter screen 2 and the large end surface of the truncated cone is 10 mm, the spacing between filter screen 2 and filter screen 1 is 10 mm, the apertures of filter screens 1 and 2 are both 60 mesh, the aperture of filter screen 3 is 600-800 mesh, the aperture of support screen 1 is 50 mesh, the aperture of support screen 2 is 20 mesh, and the aperture of support screen 3 is 10 mesh.

7. The production device of sub-spun polyester pre-oriented yarn according to claim 2, characterized in that: The bottom surface of the sand cup is a plane m; the upper surface of the first diverter plate is provided with an inverted conical groove, and the lower surface is provided with a semicircular groove a1 and a semicircular groove b1; the upper surface of the second diverter plate is provided with a semicircular groove a2 and a semicircular groove b2, and the lower surface is provided with a semicircular groove a3 and a semicircular groove b3; the upper surface of the spinneret is a plane n; The plane m and the inner surface of the inverted cone groove together form an inverted cone cavity; the inner surface of the semicircular groove a1 and the inner surface of the semicircular groove a2 together form a semi-cylindrical cavity a*, and the inner surface of the semicircular groove b1 and the inner surface of the semicircular groove b2 together form a semi-cylindrical cavity b*; the semicircular groove a3 and the plane m together form a semi-cylindrical cavity a#, and the semi-circular groove b3 and the plane m together form a semi-cylindrical cavity b#; The upper surface of the second splitter plate is pressurized and connected to the lower surface of the first splitter plate through an aluminum pad, and the lower surface of the second splitter plate is pressurized and connected to the spinneret through an aluminum pad.

8. The production device of sub-spinning polyester pre-oriented yarn according to claim 1, characterized in that: The inverted conical cavity is in the shape of an inverted truncated cone, with a large bottom surface having a diameter of 104-120 mm and a height of 15-18 mm. The angle between the busbar and the large bottom surface is 18-20°. The upper ends of the first diversion hole a' and the first diversion hole b' are both located on the small end of the inverted truncated cone; the height of the semi-cylindrical cavity a* and the semi-cylindrical cavity b* is 2-4 mm; the total number of the second diversion holes is 120-130, and the aperture is 1.4-1.6 mm; the height of the semi-cylindrical cavity a# and the semi-cylindrical cavity b# is 1.5-3 mm.

9. A method for producing sub-spun polyester pre-oriented yarn, characterized in that: The production device for sub-spinning polyester pre-oriented yarn as claimed in any one of claims 1 to 8 is used, and during the spinning process, the pumping volume, S1, and S2 are adjusted so that the extrusion pressure of the first diversion hole a' and the first diversion hole b' reaches 9-10 MPa.

10. The method for producing sub-spun polyester pre-oriented yarn according to claim 9, characterized in that: The linear density deviation rate of two bundles of yarn coming out of the same spinneret is less than 1.0%, the linear density variation coefficient CV value of the two bundles of yarn is less than 0.6%, the unevenness rate of each bundle of yarn is less than 1.4%, and the diameter deviation rate of any two single yarns coming out of the same spinneret is less than 15%.

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