A method and apparatus for preparing irregularly shaped polyester fibers

Abstract

This invention belongs to the field of polyester fiber preparation technology, and relates to a method and apparatus for preparing profiled polyester fibers. The apparatus includes a spinning metering device, which comprises a melt delivery pump, a metering pump, a pump plate, and a pump plate heater and a melt cooler located between the pump plate and the metering pump. The pump plate heater has bolt through holes, a slurry outlet, and a slurry inlet corresponding to the pump plate. Its resistance wires are uniformly arranged around the slurry outlet. A temperature control system is used to link with the metering pump motor to achieve precise temperature control of the pump plate heater during pump operation. The melt cooler includes a cooling pipe fitted onto the melt pipe, a compressed air storage tank, and an electromagnetic control valve YV. The cooling pipe and the melt pipe form a jacket, and one end of the jacket is connected to the compressed air storage tank. The preparation method includes spinning metering, cooling, and hot stretching processes. This invention solves the problems of limited melt temperature adjustment range and insufficient heating uniformity in existing methods, and is suitable for the production of profiled polyester fibers.

Description

Technical Field

[0001] This invention belongs to the field of polyester fiber preparation technology, and relates to a method and apparatus for preparing irregularly shaped polyester fibers. Background Technology

[0002] In existing polyester fiber preparation technology, melt temperature control mainly relies on the spinning box heated by the biphenyl furnace. One biphenyl furnace needs to heat 18-24 spinning boxes at the same time. This "one-to-many" centralized heating mode means that the temperature parameters output by the biphenyl furnace need to take into account the average demand of all boxes, making it impossible to adjust the melt temperature of a single spinning position within a large range according to its own process requirements.

[0003] Furthermore, existing technologies mostly heat and maintain the melt at the spinneret, such as the electrically heated bottom heater disclosed in patent CN116555925B and the air-blowing bottom heater disclosed in patent CN117926431B, both of which belong to the end-extrusion heating method. This type of heating method has significant drawbacks: on the one hand, the heating position is close to the bottom of the spinneret, making it susceptible to interference from cooling air, resulting in deviations in the temperature control of the profiled filaments; on the other hand, in the radiant heating mode, the heat source gradually decreases from the outer ring to the inner ring, making it difficult to ensure the uniformity of the melt temperature, which in turn leads to problems such as tip injection, filament drift, tip breakage, and low dyeing yield in the subsequent spinning process. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and to provide a method and apparatus for preparing irregularly shaped polyester fibers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A device for preparing profiled polyester fibers includes a spinning metering device, which includes a melt transfer pump, a metering pump, and a pump plate located below the metering pump. The pump plate is provided with bolt holes, a slurry outlet hole, and a slurry inlet hole. The spinning metering device also includes a pump plate heater and a melt cooler.

[0007] A pump plate heater is installed between the pump plate and the metering pump. The pump plate heater maintains and heats the metered melt, eliminating the drawback of existing spinning boxes that cannot precisely adjust the melt temperature at a single spinning position. It compensates for the heat loss from the spinneret, ensuring smooth melt extrusion, preventing fiber breakage during production, and reducing fiber breakage rate and elongation CV value. The pump plate heater is equipped with bolt through holes, slurry outlet holes, slurry inlet holes, and resistance wires. The number of bolt through holes is the same as the number of bolt holes, and they are all connected. The number of slurry outlet holes is the same as the number of slurry outlet holes, and they are all connected. The number of slurry inlet holes is the same as the number of slurry inlet holes, and they are all connected. The resistance wires are arranged around the slurry outlet holes, and the shortest distance to each slurry outlet hole is the same, ensuring that… Heat is evenly and efficiently transferred to each slurry outlet, improving the temperature uniformity after melt distribution. The resistance wire is composed of heating resistors R1, R2, and R3 connected in parallel. Parts of the melt pipe and each slurry outlet branch pipe are located inside the spinning box and cannot be directly removed. If the resistance wire is directly added to the pump plate, an electric heating module needs to be added inside the spinning box, which poses significant safety hazards (such as the risk of heat superposition with the biphenyl vapor heating system inside the spinning box). At the same time, if the electric heating module fails, the biphenyl inside the spinning box needs to be discharged, the pump plate needs to be cut and removed, and then re-welded and replaced, which is complicated and costly. This invention avoids this problem by setting an independent and detachable pump plate heater between the pump plate and the metering pump.

[0008] The melt cooler includes a cooling pipe, a compressed air storage tank, and an electromagnetic control valve YV. The melt delivery pump delivers melt from bottom to top to the slurry inlet through the melt pipe. The melt then enters the metering pump through the slurry inlet, then the slurry outlet, then the slurry outlet, and then sequentially passes through the slurry outlet branch pipe and the connector fixed in the spinning box to enter the spinning assembly in the spinning box. Finally, it is extruded from the spinneret holes of the spinneret. The number of spinning assemblies, connectors, and slurry outlet branch pipes is the same as the number of slurry outlet holes and they correspond one-to-one. The cooling pipe is sleeved on the melt pipe, and the two form a jacket. The end of the jacket near the pump plate is connected to the compressed air storage tank. The electromagnetic control valve YV is installed at the outlet of the compressed air storage tank.

[0009] The metering pump's motor M, solenoid control valve YV, heating resistors R1, R2, and R3 are connected to electronic components and wires, so that when the metering pump's motor M is running, the solenoid control valve YV is closed, and the temperature of heating resistors R1, R2, and R3 reaches 317-322℃; when the metering pump's motor M stops running, the solenoid control valve YV is opened, and the temperature of heating resistors R1, R2, and R3 reaches 272-277℃.

[0010] When the metering pump motor M is running, the temperature of the pump plate heater is controlled at 317-322℃, which is 30-40℃ higher than the spinning box temperature. This is because the inner surface of the spinneret orifice of the profiled filament is large, and the polyester (PET) melt requires a higher temperature to maintain good fluidity. In addition, the profiled filament has a large specific surface area and cools down quickly. After being extruded from the spinneret, heat is dissipated quickly. Therefore, it is necessary to maintain a uniform and stable temperature on the spinneret surface and a relatively high temperature. When the metering pump motor M stops running, the temperature of the pump plate heater is controlled at 272-277℃, which is 5-10℃ lower than the spinning box temperature. This is because the glass transition temperature of polyester melt is about 260℃. This temperature range can maintain good fluidity of the melt and avoid the melt from staying in the pipeline for too long, which would cause degradation due to heat accumulation.

[0011] As a preferred technical solution:

[0012] The apparatus for preparing irregularly shaped polyester fibers as described above includes electronic components such as switch 1QF, temperature controller TC, fuse 1FU, fuse 2FU, temperature sensing resistor Rt, normally closed contact KA1, normally open contact KA2, solid-state relay SSR, fuse 6FU, fuse 7FU, fuse 8FU, frequency converter VVVF, switch 2QF, fuse 3FU, fuse 4FU, fuse 5FU, relay KA, and rotary switch SB.

[0013] The conductors include phase conductor L1, phase conductor L2, phase conductor L3, and neutral conductor N;

[0014] The connection methods of the metering pump motor M, solenoid control valve YV, heating resistor R1, heating resistor R2, heating resistor R3, and electronic components and wires are as follows:

[0015] L1, L2, L3 are connected to 1QF;

[0016] The two-phase power supply terminals of TC are connected to L3 via 1FU; the common terminal I of TC is connected to N via 2FU; the temperature detection terminal and common terminal II of TC are connected to the two ends of Rt respectively; the DI1 terminal, KA1 terminal and COM terminal of TC are connected to form the first channel CH1 of TC, and the temperature control range of the first channel CH1 is 272-277℃; the DI2 terminal, KA2 terminal and COM terminal of TC are connected to form the second channel CH2 of TC, and the temperature control range of the second channel CH2 is 312-317℃.

[0017] The V+ terminal of the TC is connected to the V+ terminal of the SSR, and the V- terminal of the TC is connected to the V- terminal of the SSR.

[0018] The three-phase power input terminal I of the SSR is connected to L1 via 6FU; the three-phase power input terminal II of the SSR is connected to L2 via 7FU; the three-phase power input terminal III of the SSR is connected to L3 via 8FU; the three-phase power output terminals I, II, and III of the SSR are connected to N via R1, R2, and R3 respectively.

[0019] The R terminal of the VVVF is connected to L3 via 2QF and 3FU in sequence; the S terminal of the VVVF is connected to L2 via 2QF and 4FU in sequence; the T terminal of the VVVF is connected to L1 via 2QF and 5FU in sequence; the MC terminal of the VVVF is connected to L3; the MA terminal of the VVVF is connected to N via KA; the S1 and SC terminals of the VVVF are connected to both ends of SB respectively; the U, V, and W terminals of the VVVF are connected to the three three-phase input terminals of M (as the power supply terminals for the motor) respectively; and the two ends of YV are connected to N and L3 respectively.

[0020] The apparatus for preparing profiled polyester fibers as described above further includes a hot stretching device, which consists of a counter-blowing rectifier heating cylinder and a stretching roller. Along the direction of fiber bundle running, the stretching roller is located in front of the counter-blowing rectifier heating cylinder.

[0021] The counter-blown rectifier heating cylinder includes an outer cylinder, an inner cylinder, a C-shaped groove, a spherical pressure stabilizing chamber, and a compressed air pipe;

[0022] Both the outer cylinder and the inner cylinder are closed cylinders at both ends. The inner cylinder is located inside the outer cylinder and the two are coaxial. The bottom of the inner cylinder is in contact with the bottom of the outer cylinder. The height of the inner cylinder is less than the height of the outer cylinder. The outer diameter of the inner cylinder is less than the inner diameter of the outer cylinder. The inner cylinder has uniformly distributed flow-rectifying holes on its wall. The top of the outer cylinder has a hot air inlet.

[0023] Both the C-shaped groove and the spherical pressure stabilizing chamber are located inside the inner cylinder; the C-shaped groove is arranged vertically, with its opening facing away from the spherical pressure stabilizing chamber and a compressed air outlet at the bottom of the groove, which is connected to the spherical pressure stabilizing chamber; one end of the compressed air pipe is connected to the spherical pressure stabilizing chamber, and the other end passes through the inner cylinder and the outer cylinder in sequence;

[0024] The top of the outer cylinder is provided with an upper filament inlet, and the top of the inner cylinder is provided with a lower filament inlet. A vertically arranged guide tube is provided between the top of the outer cylinder and the top of the inner cylinder. The upper filament inlet, the lower filament inlet, the guide tube, and the C-shaped groove correspond one-to-one. The two ends of the guide tube are connected to their corresponding upper filament inlets and lower filament inlets, respectively. The upper filament inlet, the lower filament inlet, and the guide tube are all located directly above the groove space of their corresponding C-shaped groove.

[0025] Existing technologies typically employ a hot roller heating method (using three heating rollers and one stretching roller for hot stretching, as described in patent CN114355851B) during the hot stretching process. The filaments are in direct contact with the hot rollers, making it difficult to achieve flexible and precise heating control for filaments of different specifications and properties, thus failing to meet diverse production needs. To address this issue, this invention improves the hot stretching device by having the filaments first pass through a counter-blowing rectifier heating cylinder before being stretched using a single stretching roller. Compared to the hot roller heating method, this significantly reduces the contact between the filaments and the rollers. The counter-blowing rectifier heating cylinder of the hot stretching device features a coaxial design of the outer and inner cylinders. Uniform hot air convection is achieved through evenly distributed C-shaped grooves and a spherical pressure stabilizing chamber. Combined with the corresponding arrangement of the guide tube and the filament inlet, this ensures uniform heating and stretching of the filament bundle, further improving the stability of fiber breaking elongation and full roll rate.

[0026] The apparatus for preparing shaped polyester fibers as described above has an inner cylinder with a height of 160-180 mm, an outer cylinder with a height 19-21 mm greater than the inner cylinder, an outer diameter of 220-230 mm, an inner diameter of 23-27 mm greater than the inner cylinder, and a wall thickness of 3-5 mm.

[0027] In the aforementioned apparatus for preparing irregularly shaped polyester fibers, the hot air inlet is coaxial with the outer cylinder.

[0028] The apparatus for preparing profiled polyester fibers as described above further includes a hot air pipe in the blown rectifier heating cylinder, which is located outside the outer cylinder and connected to the hot air inlet.

[0029] In the aforementioned apparatus for preparing irregularly shaped polyester fibers, the vertical central axis of the spherical pressure stabilizing chamber coincides with the central axis of the inner cylinder.

[0030] The apparatus for preparing shaped polyester fibers as described above has 20-24 C-shaped grooves, all of which are evenly distributed around the vertical central axis of the spherical pressure stabilizing chamber.

[0031] In the apparatus for preparing profiled polyester fibers as described above, each C-shaped groove has 8-10 compressed air outlets, arranged vertically with spacing between them. The distance between two adjacent compressed air outlets is 10-12% of the length of the C-shaped groove. The length of the C-shaped groove is 12-15% of the height of the inner cylinder. The cross-section of the C-shaped groove is an arc with a central angle greater than or equal to 250° and less than or equal to 270°. The distance between the C-shaped groove and the top of the inner cylinder is 38-40% of the height of the inner cylinder. The distance between the C-shaped groove and the wall of the inner cylinder is 15-18% of the inner diameter of the inner cylinder.

[0032] In the aforementioned apparatus for preparing profiled polyester fibers, the central axis of the compressed air tube coincides with the vertical central axis of the spherical pressure stabilizing chamber, and the compressed air tube passes through the hot air inlet with a gap between them.

[0033] The present invention also provides a method for preparing profiled polyester fibers, using an apparatus for preparing profiled polyester fibers as described in any of the preceding claims.

[0034] As a preferred technical solution:

[0035] The preparation method of the above-mentioned profiled polyester fiber has the following process flow: metering by spinning metering device → component distribution extrusion (spinneret holes are distributed in concentric circles) → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching → second comb guide → main networker → winding and forming.

[0036] The spinning process parameters include: spinning temperature 294-296℃, cooling air pressure 18-21Pa, oil rack height 600-750mm, and oil content 1.03-1.25%;

[0037] The winding process parameters include: hot stretching speed 3680-4350m / min, hot stretching temperature 110-120℃, winding speed 3600-4200m / min, pre-network pressure 0.07-0.09bar, and main network pressure 0.35-0.45bar.

[0038] The specifications of profiled polyester fibers are 75-83 dtex / 144-196 f, and the cross-sectional shape of the monofilament is cross-shaped, H-shaped, or king-shaped; the breaking elongation of profiled polyester fibers is 19.2-30.5%, the breaking elongation unevenness (CV) value is 3.8-6.2%, and the full roll rate is a key indicator for measuring the efficiency of full roll yarn production in chemical fiber production. Full roll rate = ×100%, where the total weight of the silk cake off the machine = the total weight of the fully rolled silk cake + the total weight of the broken silk cake) 96.6-99.1%.

[0039] Beneficial effects:

[0040] (1) By setting a pump plate heater between the pump plate and the metering pump, the present invention can heat and keep the melt of a single spinning position separately, compensate for the heat loss of the spinneret, make the melt temperature control range more flexible, and solve the limitations of centralized heating of biphenyl furnace.

[0041] (2) In this invention, the heating position of the pump plate heater is far away from the cooling wind interference area to avoid temperature control deviation of the irregular filaments. The resistance wire is evenly arranged around the slurry outlet hole to ensure uniform heat transfer, thereby reducing the injection head and breakage phenomenon, reducing the fiber elongation CV value, and increasing the post-spinning dyeing M rate.

[0042] (3) In this invention, the pump plate heater adopts an independent and detachable design and is installed between the pump plate and the metering pump. There is no need to add an electric heating module in the spinning box, which avoids the risk of heat superposition with the biphenyl vapor heating system. When the heater fails, it can be directly disassembled and replaced without discharging biphenyl or cutting the pump plate, which greatly reduces the complexity and cost of maintenance.

[0043] (4) In this invention, the melt cooler forms a jacket structure with the melt pipe through the cooling pipe, and together with the compressed air storage tank and the electromagnetic control valve, the cooling function is turned on when the metering pump stops, and the heater temperature is controlled at 272-277℃, which not only ensures the fluidity of the melt, but also avoids degradation caused by high temperature.

[0044] (5) The hot stretching device adopts a coaxial design of outer cylinder and inner cylinder. The hot air is uniformly convected through the evenly distributed C-shaped groove and spherical pressure stabilizing chamber. Combined with the corresponding arrangement of the guide tube and the fiber bundle inlet, the fiber bundle is uniformly heated and stretched, which improves the stability of fiber breaking elongation and full roll rate. Attached Figure Description

[0045] Figure 1 (a) is a schematic diagram of the pump plate structure, and (b) is a schematic diagram of the pump plate heater structure.

[0046] Figure 2 A schematic diagram showing the positional relationship between the pump plate, pump plate heater, and metering pump;

[0047] Figure 3 A schematic diagram showing the connection relationship between the cooling pipes and the melt pipes;

[0048] Figure 4 This is a schematic diagram showing the connection between the metering pump motor M, solenoid control valve YV, heating resistor R1, heating resistor R2, heating resistor R3, and electronic components and wires.

[0049] Figures 5-7 This is a schematic diagram of the counter-blown rectifier heating cylinder. Figure 5 This is a top view. Figure 6 This is a side view. Figure 7 This is an exploded view;

[0050] Among them, 6.1-C-shaped groove, 6.2-compressed air pipe, 6.3-hot air pipe, 6.5-spherical pressure stabilizing chamber, 6.6-outer cylinder, 6.7-inner cylinder, 6.8-guide wire tube, 9-pump plate, 9.1-slurry outlet, 9.2-slurry inlet, 9.3-bolt hole, 10-pump plate heater, 10.1-slurry outlet, 10.2-slurry inlet, 10.3-bolt through hole, 10.4-resistance wire, 11-metering pump, 12-cooling pipe, 13-melt pipe. Detailed Implementation

[0051] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0052] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0053] Elongation at break and CV value of elongation at break: tested using a Swiss Uster-Ⅳ tensile strength tester according to GB / T14344-2022.

[0054] An apparatus for preparing profiled polyester fibers includes a spinning metering device and a hot stretching device;

[0055] like Figure 1 and Figure 2 As shown, the spinning metering device includes a melt transfer pump, a metering pump 11, a pump plate heater 10, a melt cooler, and a pump plate 9 located below the metering pump 11.

[0056] like Figure 1 As shown in (a), the pump plate 9 is provided with bolt holes 9.3, slurry outlet holes 9.1 and slurry inlet holes 9.2;

[0057] like Figure 2 As shown, the pump plate heater 10 is installed between the pump plate 9 and the metering pump 11; Figure 1 As shown in (b), the pump plate heater 10 is provided with bolt through holes 10.3, slurry outlet holes 10.1, slurry inlet holes 10.2 and resistance wires 10.4. The number of bolt through holes 10.3 is the same as that of bolt holes 9.3 and they are connected one-to-one. The number of slurry outlet holes 10.1 is the same as that of slurry outlet holes 9.1 and they are connected one-to-one. The number of slurry inlet holes 10.2 is the same as that of slurry inlet holes 9.2 and they are connected one-to-one. The resistance wires 10.4 are arranged around the slurry outlet holes 10.1 and the shortest distance to each slurry outlet hole 10.1 is the same. The resistance wires 10.4 are formed by heating resistors R1, R2 and R3 connected in parallel.

[0058] like Figure 3 As shown, the melt cooler includes a cooling pipe 12, a compressed air storage tank, and an electromagnetic control valve YV. The melt delivery pump delivers melt from bottom to top to the inlet hole 9.2 through the melt pipe 13. The cooling pipe 12 is fitted onto the melt pipe 13, and the two form a jacket. The end of the jacket near the pump plate 9 is connected to the compressed air storage tank. The electromagnetic control valve YV is installed at the outlet of the compressed air storage tank.

[0059] like Figure 4As shown, the electronic components include switch 1QF, temperature controller TC, fuse 1FU, fuse 2FU, temperature sensing resistor Rt, normally closed contact KA1, normally open contact KA2, solid-state relay SSR, fuse 6FU, fuse 7FU, fuse 8FU, frequency converter VVVF, switch 2QF, fuse 3FU, fuse 4FU, fuse 5FU, relay KA, and rotary switch SB; the wires include phase wire L1, phase wire L2, phase wire L3, and neutral wire N;

[0060] The motor M, solenoid control valve YV, heating resistors R1, R2, and R3 of metering pump 11 are connected to electronic components and wires. The connection method is as follows: L1, L2, and L3 are connected to 1QF; the two-phase power supply terminals of TC are connected to L3 through 1FU; the common terminal I of TC is connected to N through 2FU; the temperature detection terminal and common terminal II of TC are connected to both ends of Rt respectively; the DI1 terminal, KA1 terminal, and COM terminal of TC are connected to form the first channel CH1 of TC, and the temperature control range of the first channel CH1 is 272-277℃; the DI2 terminal, KA2 terminal, and COM terminal of TC are connected to form the second channel CH2 of TC, and the temperature control range of the second channel CH2 is 312-317℃; the V+ terminal of TC is connected to the V+ terminal of SSR, and the V- terminal of TC is connected to the V- terminal of SSR; the three-phase power supply of SSR... Terminal I is connected to L1 via 6FU; the three-phase power input terminal II of the SSR is connected to L2 via 7FU; the three-phase power input terminal III of the SSR is connected to L3 via 8FU; the three-phase power output terminals I, II, and III of the SSR are connected to N via R1, R2, and R3 respectively; the R terminal of the VVVF is connected to L3 via 2QF and 3FU; the S terminal of the VVVF is connected to L2 via 2QF and 4FU; the T terminal of the VVVF is connected to L1 via 2QF and 5FU; the MC terminal of the VVVF is connected to L3; the MA terminal of the VVVF is connected to N via KA; the S1 and SC terminals of the VVVF are connected to both ends of SB respectively; the U, V, and W terminals of the VVVF are connected to the three three-phase input terminals of M respectively; the two ends of YV are connected to N and L3 respectively.

[0061] The hot stretching device consists of a counter-blowing rectifier heating cylinder and a stretching roller;

[0062] like Figures 5-7 As shown, the counter-blowing rectifier heating cylinder includes an outer cylinder 6.6, an inner cylinder 6.7, a C-shaped groove 6.1, a spherical pressure stabilizing chamber 6.5, a compressed air pipe 6.2, and a hot air pipe 6.3;

[0063] Both the outer cylinder 6.6 and the inner cylinder 6.7 are closed cylinders at both ends. The inner cylinder 6.7 is located inside the outer cylinder 6.6 and the two are coaxial. The bottom of the inner cylinder 6.7 is in contact with the bottom of the outer cylinder 6.6. The height of the inner cylinder 6.7 is less than the height of the outer cylinder 6.6. The outer diameter of the inner cylinder 6.7 is less than the inner diameter of the outer cylinder 6.6. The inner cylinder 6.7 has uniformly distributed flow-rectifying holes on its wall. The top of the outer cylinder 6.6 has a hot air inlet, which is coaxial with the outer cylinder 6.6.

[0064] Both the C-shaped grooves 6.1 and the spherical pressure regulating chambers 6.5 are located inside the inner cylinder 6.7, with the vertical central axis of the spherical pressure regulating chamber 6.5 coinciding with the central axis of the inner cylinder 6.7. There are 20-24 C-shaped grooves 6.1, each with a superior arc cross-section. All C-shaped grooves 6.1 are evenly distributed around the vertical central axis of the spherical pressure regulating chamber 6.5. The C-shaped grooves 6.1 are vertically arranged, with their openings facing away from the spherical pressure regulating chamber 6.5 and their bottoms... It is equipped with a compressed air outlet, which is connected to the spherical pressure stabilizing chamber 6.5. The compressed air outlets on each C-shaped groove 6.1 are arranged at vertical intervals. One end of the compressed air pipe 6.2 is connected to the spherical pressure stabilizing chamber 6.5, and the other end passes through the inner cylinder 6.7 and the outer cylinder 6.6 in sequence. The central axis of the compressed air pipe 6.2 coincides with the vertical central axis of the spherical pressure stabilizing chamber 6.5. The compressed air pipe 6.2 passes through the hot air inlet and leaves a gap between it and the hot air inlet.

[0065] The top of the outer cylinder 6.6 is provided with an upper filament inlet, and the top of the inner cylinder 6.7 is provided with a lower filament inlet. A vertically arranged guide tube 6.8 is provided between the top of the outer cylinder 6.6 and the top of the inner cylinder 6.7. The upper filament inlet, the lower filament inlet, the guide tube 6.8, and the C-shaped groove 6.1 correspond one-to-one. The two ends of the guide tube 6.8 are connected to their corresponding upper filament inlets and lower filament inlets, respectively. The upper filament inlet, the lower filament inlet, and the guide tube 6.8 are all located directly above the groove space of their corresponding C-shaped groove 6.1.

[0066] The hot air duct 6.3 is located outside the outer cylinder 6.6 and is connected to the hot air inlet;

[0067] Along the direction of the filament bundle, the stretching roller is located in front of the counter-blowing rectifier heating cylinder.

[0068] The working process of the spinning metering device is as follows: First, close 1QF and 2QF to put VVVF in standby mode;

[0069] Subsequently, the melt is transported from bottom to top by the melt delivery pump through the melt pipeline to the slurry inlet, and then enters the metering pump through the slurry inlet. After the metering pump accurately measures the melt, it is transported through the slurry outlet to the slurry outlet for subsequent spinning component distribution and extrusion.

[0070] When in spinning mode, SB is turned on, VVVF controls the short circuit between terminals S1 and SC, M starts, and simultaneously VVVF's MA and MC terminals close, KA coil is energized and attracted, KA1 is opened, KA2 is closed, DI2 is connected to TC's COM terminal, TC's second channel CH2 is activated, and Rt monitors the pump plate heater temperature in real time: if the temperature is below 317℃, TC's V+ and V- terminals output DC12V voltage, causing SSR to work and triggering R1, R2, and R3 to be energized and heated; if the temperature is above 322℃, V+ and V- terminals stop outputting DC12V voltage, SSR stops working, R1, R2, and R3 are de-energized and stop heating, YV is turned off, and the compressed air circuit of the melt cooler does not work, keeping the pump plate heater temperature at 317-322℃ (30-40℃ higher than the chamber temperature) to meet the requirements of high-profile yarns;

[0071] When in non-spinning state, VVVF receives a stop signal, M stops operating, MA and MC terminals disconnect, KA coil is de-energized, KA2 returns to its normally open state, cutting off CH2 channel, KA1 resets and closes, DI1 connects to COM terminal, TC's first channel CH1 is activated, and Rt monitors the pump plate heater temperature again: when the temperature is below 272℃, TC activates SSR through the output voltage of V+ and V- terminals, energizing R1, R2, and R3 for heating; when the temperature is above 277℃, SSR stops working, R1, R2, and R3 are de-energized and cooled, and YV opens, the compressed air in the compressed air storage tank cools the retained melt through the jacket formed by the cooling pipe and the melt pipe, keeping the pump plate heater temperature at 272-277℃ (5-10℃ lower than the box temperature) to prevent melt degradation.

[0072] When the subsequently formed filament bundle passes through the thermal stretching device, it enters from the upper filament bundle inlet at the top of the outer cylinder, passes through the corresponding guide tube, and exits from the lower filament bundle inlet at the top of the inner cylinder, entering the area above the corresponding C-shaped groove. At this time, hot air enters the device through the hot air pipe and hot air inlet in sequence; part of the hot air enters the space between the inner and outer cylinders, and the other part of the hot air heats the compressed air entering the spherical pressure stabilizing chamber from the compressed air pipe; the heated compressed air is blown out from the compressed air outlet at the bottom of the C-shaped groove, and the blown compressed air disperses the filament bundle, creating gaps between the filaments; while the hot air entering the space between the inner and outer cylinders enters the inner cylinder through the evenly distributed rectification holes on the inner cylinder wall. This hot air can enter the gaps between the filaments, and together with the hot compressed air blown out from the compressed air outlet, it achieves uniform heating of the filament bundle.

[0073] Example 1

[0074] A method for preparing profiled polyester fibers, using the apparatus for preparing profiled polyester fibers as described above, includes the following specific steps:

[0075] (1) Preparation of polyester melt;

[0076] The process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity is 0.64 dL / g);

[0077] The relevant process parameters are as follows: slurry level 70%, PTA mass in slurry accounts for 70% of the total mass of PTA and EG; first esterification temperature 263℃, first esterification pressure 55kPa, second esterification temperature 265℃, second esterification pressure 15kPa, prepolymerization upper chamber temperature 273℃, prepolymerization upper chamber pressure 12kPa, prepolymerization lower chamber temperature 275℃, prepolymerization lower chamber pressure 1kPa, final polymerization inlet temperature 278℃, final polymerization outlet temperature 281℃, final polymerization vacuum degree 140Pa;

[0078] (2) Preparation of irregularly shaped polyester fibers;

[0079] The process involves: metering by the spinning metering device of the shaped polyester fiber preparation device → component distribution and extrusion (spinnerets are distributed in concentric circles) → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching (by the hot stretching device of the shaped polyester fiber preparation device) → second comb guide → main networker → winding and forming.

[0080] The spinning process parameters are as follows: spinning temperature 296℃, no-wind zone height 20mm, cooling air temperature 21℃, cooling air humidity 86%, cooling air pressure 18Pa, oil rack height 750mm, and oil content 1.25%.

[0081] Dimensional parameters of the apparatus for preparing profiled polyester fibers: the height of the inner cylinder is 160 mm, the height of the outer cylinder is 19 mm greater than the height of the inner cylinder, the outer diameter of the inner cylinder is 220 mm, the inner diameter of the outer cylinder is 27 mm greater than the outer diameter of the inner cylinder, the wall thickness of the inner cylinder is 3 mm, the number of C-grooves is 20, the length of the C-grooves is 12% of the height of the inner cylinder, the number of compressed air outlets on each C-groove is 8, the distance between two adjacent compressed air outlets on each C-groove is 12% of the length of the C-groove, the central angle of the dominant arc cross-section of the C-groove is 250°, the distance between the C-groove and the top of the inner cylinder is 38% of the height of the inner cylinder, and the distance between the C-groove and the cylinder wall of the inner cylinder is 18% of the inner diameter of the inner cylinder.

[0082] The winding process parameters are: hot stretching speed 3680 m / min, hot stretching temperature 110℃, winding speed 3600 m / min, pre-network pressure 0.07 bar, and main network pressure 0.35 bar.

[0083] The final shaped polyester fiber has a specification of 75 dtex / 196f and an H-shaped monofilament cross-section. The shaped polyester fiber has a breaking elongation of 22.1%, a breaking elongation unevenness CV value of 4.7%, and a roll rate of 98.6%.

[0084] Example 2

[0085] A method for preparing profiled polyester fibers, using the apparatus for preparing profiled polyester fibers as described above, includes the following specific steps:

[0086] (1) Preparation of polyester melt;

[0087] The process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity is 0.65 dL / g);

[0088] The relevant process parameters are as follows: slurry level 70%, PTA mass in slurry accounts for 70% of the total mass of PTA and EG; first esterification temperature 262℃, first esterification pressure 60kPa, second esterification temperature 263℃, second esterification pressure 17kPa, prepolymerization upper chamber temperature 272.5℃, prepolymerization upper chamber pressure 11kPa, prepolymerization lower chamber temperature 274℃, prepolymerization lower chamber pressure 1.2kPa, final polymerization inlet temperature 277℃, final polymerization outlet temperature 280℃, final polymerization vacuum degree 148Pa;

[0089] (2) Preparation of irregularly shaped polyester fibers;

[0090] The process involves: metering by the spinning metering device of the shaped polyester fiber preparation device → component distribution and extrusion (spinnerets are distributed in concentric circles) → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching (by the hot stretching device of the shaped polyester fiber preparation device) → second comb guide → main networker → winding and forming.

[0091] The spinning process parameters are as follows: spinning temperature 295℃, no-wind zone height 25mm, cooling air temperature 20℃, cooling air humidity 83%, cooling air pressure 19Pa, oil rack height 700mm, and oil content 1.2%.

[0092] Dimensional parameters of the apparatus for preparing profiled polyester fibers: the height of the inner cylinder is 170 mm, the height of the outer cylinder is 20 mm greater than the height of the inner cylinder, the outer diameter of the inner cylinder is 225 mm, the inner diameter of the outer cylinder is 26 mm greater than the outer diameter of the inner cylinder, the wall thickness of the inner cylinder is 4 mm, the number of C-grooves is 20, the length of the C-grooves is 13% of the height of the inner cylinder, the number of compressed air outlets on each C-groove is 9, the distance between two adjacent compressed air outlets on each C-groove is 11.5% of the length of the C-groove, the central angle of the dominant arc cross-section of the C-groove is 260°, the distance between the C-groove and the top of the inner cylinder is 39% of the height of the inner cylinder, and the distance between the C-groove and the cylinder wall of the inner cylinder is 17% of the inner diameter of the inner cylinder.

[0093] The winding process parameters are: hot stretching speed 4000m / min, hot stretching temperature 112℃, winding speed 3700m / min, pre-network pressure 0.08bar, and main network pressure 0.39bar.

[0094] The final shaped polyester fiber has a specification of 83dtex / 144f and a cross-shaped monofilament cross section. The shaped polyester fiber has a breaking elongation of 30.5%, a breaking elongation unevenness CV value of 3.8%, and a roll rate of 99.1%.

[0095] Example 3

[0096] A method for preparing profiled polyester fibers, using the apparatus for preparing profiled polyester fibers as described above, includes the following specific steps:

[0097] (1) Preparation of polyester melt;

[0098] The process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity is 0.66 dL / g);

[0099] The relevant process parameters are as follows: slurry level 70%, PTA mass in slurry accounts for 70% of the total mass of PTA and EG; first esterification temperature 261℃, first esterification pressure 62kPa, second esterification temperature 262.5℃, second esterification pressure 18kPa, prepolymerization upper chamber temperature 272℃, prepolymerization upper chamber pressure 10kPa, prepolymerization lower chamber temperature 274℃, prepolymerization lower chamber pressure 1.35kPa, final polymerization inlet temperature 276.5℃, final polymerization outlet temperature 279℃, final polymerization vacuum degree 150Pa;

[0100] (2) Preparation of irregularly shaped polyester fibers;

[0101] The process involves: metering by the spinning metering device of the shaped polyester fiber preparation device → component distribution and extrusion (spinnerets are distributed in concentric circles) → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching (by the hot stretching device of the shaped polyester fiber preparation device) → second comb guide → main networker → winding and forming.

[0102] The spinning process parameters are as follows: spinning temperature 295℃, no-wind zone height 30mm, cooling air temperature 19℃, cooling air humidity 81%, cooling air pressure 20Pa, oil rack height 650mm, and oil content 1.1%.

[0103] The dimensional parameters of the apparatus for preparing profiled polyester fibers are as follows: the height of the inner cylinder is 175 mm, the height of the outer cylinder is 20.5 mm greater than that of the inner cylinder, the outer diameter of the inner cylinder is 225 mm, the inner diameter of the outer cylinder is 25 mm greater than that of the inner cylinder, the wall thickness of the inner cylinder is 4 mm, the number of C-grooves is 24, the length of the C-grooves is 14% of the height of the inner cylinder, the number of compressed air outlets on each C-groove is 9, the distance between two adjacent compressed air outlets on each C-groove is 11% of the length of the C-groove, the central angle of the dominant arc cross-section of the C-groove is 265°, the distance between the C-groove and the top of the inner cylinder is 39.5% of the height of the inner cylinder, and the distance between the C-groove and the cylinder wall of the inner cylinder is 16% of the inner diameter of the inner cylinder.

[0104] The winding process parameters are: hot stretching speed 4200 m / min, hot stretching temperature 115℃, winding speed 4000 m / min, pre-network pressure 0.085 bar, and main network pressure 0.41 bar.

[0105] The final shaped polyester fiber has a specification of 75dtex / 196f and a cross-sectional shape of king-shaped monofilament. The shaped polyester fiber has a breaking elongation of 28.3%, a breaking elongation unevenness CV value of 4.1%, and a roll rate of 98.8%.

[0106] Example 4

[0107] A method for preparing profiled polyester fibers, using the apparatus for preparing profiled polyester fibers as described above, includes the following specific steps:

[0108] (1) Preparation of polyester melt;

[0109] The process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity is 0.67 dL / g);

[0110] The relevant process parameters are as follows: slurry level 70%, PTA mass in slurry accounts for 70% of the total mass of PTA and EG; first esterification temperature 258℃, first esterification pressure 65kPa, second esterification temperature 260℃, second esterification pressure 20kPa, prepolymerization upper chamber temperature 271℃, prepolymerization upper chamber pressure 9.5kPa, prepolymerization lower chamber temperature 273℃, prepolymerization lower chamber pressure 1.5kPa, final polymerization inlet temperature 275℃, final polymerization outlet temperature 278℃, final polymerization vacuum degree 155Pa;

[0111] (2) Preparation of irregularly shaped polyester fibers;

[0112] The process involves: metering by the spinning metering device of the shaped polyester fiber preparation device → component distribution and extrusion (spinnerets are distributed in concentric circles) → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching (by the hot stretching device of the shaped polyester fiber preparation device) → second comb guide → main networker → winding and forming.

[0113] The spinning process parameters are as follows: spinning temperature 294℃, windless zone height 40mm, cooling air temperature 18℃, cooling air humidity 80%, cooling air pressure 21Pa, oil rack height 600mm, and oil content 1.03%.

[0114] Dimensional parameters of the apparatus for preparing profiled polyester fibers: the height of the inner cylinder is 180 mm, the height of the outer cylinder is 21 mm greater than the height of the inner cylinder, the outer diameter of the inner cylinder is 230 mm, the inner diameter of the outer cylinder is 23 mm greater than the outer diameter of the inner cylinder, the wall thickness of the inner cylinder is 5 mm, the number of C-grooves is 24, the length of the C-grooves is 15% of the height of the inner cylinder, the number of compressed air outlets on each C-groove is 10, the distance between two adjacent compressed air outlets on each C-groove is 10% of the length of the C-groove, the central angle of the dominant arc cross-section of the C-groove is 270°, the distance between the C-groove and the top of the inner cylinder is 40% of the height of the inner cylinder, and the distance between the C-groove and the cylinder wall of the inner cylinder is 15% of the inner diameter of the inner cylinder.

[0115] The winding process parameters are: hot stretching speed 4350 m / min, hot stretching temperature 120℃, winding speed 4200 m / min, pre-network pressure 0.09 bar, and main network pressure 0.45 bar.

[0116] The final shaped polyester fiber has a specification of 83dtex / 196f and a single filament cross-sectional shape of H-shape. The shaped polyester fiber has a breaking elongation of 25.2%, a breaking elongation unevenness CV value of 4.4%, and a roll rate of 98.7%.

[0117] Example 5

[0118] A method for preparing shaped polyester fibers differs from Example 1 only in that the central angle of the superior arc cross-section of the C-shaped groove is 240°.

[0119] The final shaped polyester fiber had a breaking elongation of 19.5%, a breaking elongation unevenness CV value of 5.9%, and a roll rate of 97.2%.

[0120] Compared to Example 1, the elongation at break and full roll rate of the profiled polyester fiber obtained in Example 5 were reduced, while the CV value of elongation at break unevenness was increased. This is because the central angle of the C-groove cross-section in Example 5 was smaller, resulting in a faster heating rate. The outer monofilament of the porous profiled yarn was heated quickly, and the radial diffusion of hot air was easily obstructed. Some of the hot air moved downward with the airflow generated by the high-speed movement of the yarn, superimposing with the hot air blown horizontally towards the yarn from the lower section, continuing to heat the yarn. This resulted in the yarn being heated more, with a large temperature difference between the inner and outer monofilaments. During stretching, the outer layer tension was low and the inner layer tension was high, making the yarn brittle. Consequently, problems such as low elongation at break, high CV value of elongation at break unevenness, and low full roll rate occurred.

[0121] Example 6

[0122] The only difference between this method for preparing irregularly shaped polyester fibers and Example 4 is that the central angle of the superior arc cross-section of the C-shaped groove is 280°.

[0123] The final shaped polyester fiber had a breaking elongation of 21.8%, a breaking elongation unevenness CV value of 6.2%, and a roll rate of 96.6%.

[0124] Compared with Example 4, the full roll rate of the shaped polyester fiber obtained in Example 6 was reduced, while the elongation at break and the CV value of elongation at break were increased. This is because the central angle of the C-groove cross section in Example 6 is larger, and the specific surface area of ​​the highly shaped filament is large, resulting in good heating and cooling efficiency. When the filament is running at high speed, the heating air cannot be effectively concentrated in the heating cylinder, resulting in insufficient heating of the inner filament. Consequently, the plastic deformation of the filament during stretching is significantly increased, manifested as an increase in elongation at break. Furthermore, the breakage of the inner monofilament causes the full roll rate to decrease. The excessively high elongation at break leads to aggravated tension fluctuations during stretching, resulting in a larger CV value of elongation at break.

[0125] Example 7

[0126] A method for preparing shaped polyester fibers differs from Example 1 only in that the hot stretching uses 3 heating rollers and 1 stretching roller.

[0127] The final shaped polyester fiber had a breaking elongation of 19.2%, a breaking elongation unevenness CV value of 5.8%, and a roll rate of 97.9%.

[0128] Compared with Example 1, the elongation at break and full roll rate of the shaped polyester fiber obtained in Example 7 were reduced, while the CV value of elongation at break unevenness was increased. This is because when using three heating rollers and one stretching roller for hot stretching, the filaments need to frequently contact the three heating rollers. On the one hand, friction causes the spinning tension to increase and fluctuate more, affecting the stretching uniformity. On the other hand, it is difficult to accurately control the heating temperature of different filaments, resulting in local overheating or underheating of the filaments. Uneven heating causes inconsistent plastic deformation, which is manifested as a decrease in elongation at break and an increase in the CV value of elongation at break unevenness. At the same time, the filaments are prone to breakage during stretching due to uneven strength, which in turn leads to a decrease in full roll rate.

[0129] Comparative Example 1

[0130] A method for preparing profiled polyester fibers differs from Example 1 only in that the spinning metering device does not include a pump plate heater and a melt cooler.

[0131] The final shaped polyester fiber had a breaking elongation of 15.3%, a breaking elongation unevenness CV value of 8.2%, and a roll rate of 93.3%.

[0132] Compared with Example 1, the elongation at break and full roll rate of the shaped polyester fiber prepared in Comparative Example 1 were significantly reduced, while the CV value of elongation at break unevenness was significantly increased. This is because the spinning metering device used in Comparative Example 1 lacked a pump plate heater and melt cooler, making it impossible to accurately control the melt temperature at a single spinning position. On the one hand, the melt temperature is easily affected by the temperature fluctuation of the spinning box, resulting in the inability to compensate for the temperature drop of the spinneret, which leads to poor melt fluidity. After the filament is extruded, internal stress is generated due to uneven temperature, resulting in inconsistent plastic deformation during stretching, which manifests as a decrease in elongation at break and an increase in the CV value of elongation at break unevenness. On the other hand, the shaped filament has a large specific surface area and a fast cooling rate. Without the heat preservation of the pump plate heater, the heat loss after the filament is extruded is significant, which easily leads to head injection, filament drift and breakage, resulting in a decrease in full roll rate.

Claims

1. An apparatus for preparing profiled polyester fibers, comprising a spinning metering device, the spinning metering device comprising a melt transfer pump, a metering pump (11), and a pump plate (9) located below the metering pump (11), the pump plate (9) being provided with a slurry outlet (9.1) and a slurry inlet (9.2), characterized in that, The spinning metering device also includes a pump plate heater (10) and a melt cooler; The pump plate heater (10) is installed between the pump plate (9) and the metering pump (11). The pump plate heater (10) is provided with a slurry outlet (10.1), a slurry inlet (10.2) and a resistance wire (10.4). The number of slurry outlets (10.1) and slurry outlets (9.1) are the same and they are connected in a one-to-one correspondence. The number of slurry inlets (10.2) and slurry inlets (9.2) are the same and they are connected in a one-to-one correspondence. The resistance wire (10.4) is arranged around the slurry outlet (10.1) and the shortest distance to each slurry outlet (10.1) is the same. The resistance wire (10.4) is composed of heating resistors R1, R2 and R3 connected in parallel. The melt cooler includes a cooling pipe (12), a compressed air storage tank, and an electromagnetic control valve YV. The melt delivery pump delivers melt from bottom to top to the slurry inlet (9.2) through the melt pipe (13). The cooling pipe (12) is fitted onto the melt pipe (13), and the two form a jacket. The end of the jacket near the pump plate (9) is connected to the compressed air storage tank. The electromagnetic control valve YV is installed at the outlet of the compressed air storage tank. The motor M, electromagnetic control valve YV, heating resistor R1, heating resistor R2, and heating resistor R3 of the metering pump (11) are connected to electronic components and wires, so that when the motor M of the metering pump (11) is running, the electromagnetic control valve YV is closed, and the temperature of heating resistor R1, heating resistor R2, and heating resistor R3 reaches 317-322℃; when the motor M of the metering pump (11) stops running, the electromagnetic control valve YV is opened, and the temperature of heating resistor R1, heating resistor R2, and heating resistor R3 reaches 272-277℃. The apparatus for preparing profiled polyester fibers also includes a hot stretching device, which consists of a counter-blowing rectifier heating cylinder and a stretching roller. Along the direction of fiber bundle running, the stretching roller is located in front of the counter-blowing rectifier heating cylinder. The counter-blown rectifier heating cylinder includes an outer cylinder (6.6), an inner cylinder (6.7), a C-shaped groove (6.1), a spherical pressure stabilizing chamber (6.5), and a compressed air pipe (6.2). Both the outer cylinder (6.6) and the inner cylinder (6.7) are closed cylinders at both ends. The inner cylinder (6.7) is located inside the outer cylinder (6.6) and the two are coaxial. The bottom of the inner cylinder (6.7) fits into the bottom of the outer cylinder (6.6). The height of the inner cylinder (6.7) is less than the height of the outer cylinder (6.6). The outer diameter of the inner cylinder (6.7) is less than the inner diameter of the outer cylinder (6.6). The inner cylinder (6.7) has uniformly distributed flow-rectifying holes on its wall. The top of the outer cylinder (6.6) has a hot air inlet. Both the C-shaped groove (6.1) and the spherical pressure stabilizing chamber (6.5) are located inside the inner cylinder (6.7); the C-shaped groove (6.1) is arranged vertically, with its opening facing away from the spherical pressure stabilizing chamber (6.5) and a compressed air outlet at the bottom of the groove, which is connected to the spherical pressure stabilizing chamber (6.5); one end of the compressed air pipe (6.2) is connected to the spherical pressure stabilizing chamber (6.5), and the other end passes through the inner cylinder (6.7) and the outer cylinder (6.6) in sequence; The top of the outer cylinder (6.6) is provided with an upper filament inlet, and the top of the inner cylinder (6.7) is provided with a lower filament inlet. A vertically arranged guide tube (6.8) is provided between the top of the outer cylinder (6.6) and the top of the inner cylinder (6.7). The upper filament inlet, the lower filament inlet, the guide tube (6.8), and the C-shaped groove (6.1) correspond one-to-one. The two ends of the guide tube (6.8) are connected to their corresponding upper filament inlets and lower filament inlets, respectively. The upper filament inlet, the lower filament inlet, and the guide tube (6.8) are all located directly above the groove space of their corresponding C-shaped groove (6.1).

2. The apparatus for preparing profiled polyester fibers according to claim 1, characterized in that, The electronic components include switch 1QF, temperature controller TC, fuse 1FU, fuse 2FU, temperature sensing resistor Rt, normally closed contact KA1, normally open contact KA2, solid-state relay SSR, fuse 6FU, fuse 7FU, fuse 8FU, frequency converter VVVF, switch 2QF, fuse 3FU, fuse 4FU, fuse 5FU, relay KA, and rotary switch SB; The conductors include phase conductor L1, phase conductor L2, phase conductor L3, and neutral conductor N; The connection methods of the motor M, electromagnetic control valve YV, heating resistor R1, heating resistor R2, heating resistor R3 of the metering pump (11) with electronic components and wires are as follows: L1, L2, L3 are connected to 1QF; The two-phase power supply terminals of TC are connected to L3 via 1FU; the common terminal I of TC is connected to N via 2FU; the temperature detection terminal and common terminal II of TC are connected to the two ends of Rt respectively; the DI1 terminal, KA1 terminal and COM terminal of TC are connected to form the first channel CH1 of TC, and the temperature control range of the first channel CH1 is 272-277℃; the DI2 terminal, KA2 terminal and COM terminal of TC are connected to form the second channel CH2 of TC, and the temperature control range of the second channel CH2 is 312-317℃. The V+ terminal of the TC is connected to the V+ terminal of the SSR, and the V- terminal of the TC is connected to the V- terminal of the SSR. The three-phase power input terminal I of the SSR is connected to L1 via 6FU; the three-phase power input terminal II of the SSR is connected to L2 via 7FU; the three-phase power input terminal III of the SSR is connected to L3 via 8FU; the three-phase power output terminals I, II, and III of the SSR are connected to N via R1, R2, and R3 respectively. The R terminal of the VVVF is connected to L3 via 2QF and 3FU in sequence; the S terminal of the VVVF is connected to L2 via 2QF and 4FU in sequence; the T terminal of the VVVF is connected to L1 via 2QF and 5FU in sequence; the MC terminal of the VVVF is connected to L3; the MA terminal of the VVVF is connected to N via KA; the S1 and SC terminals of the VVVF are connected to both ends of SB respectively; the U, V, and W terminals of the VVVF are connected to the three three-phase input terminals of M respectively; and the two ends of YV are connected to N and L3 respectively.

3. The apparatus for preparing profiled polyester fibers according to claim 1, characterized in that, The height of the inner cylinder (6.7) is 160-180mm, the height of the outer cylinder (6.6) is 19-21mm greater than the height of the inner cylinder (6.7), the outer diameter of the inner cylinder (6.7) is 220-230mm, the inner diameter of the outer cylinder (6.6) is 23-27mm greater than the outer diameter of the inner cylinder (6.7), and the wall thickness of the inner cylinder (6.7) is 3-5mm.

4. The apparatus for preparing profiled polyester fibers according to claim 1, characterized in that, The hot air inlet is coaxial with the outer cylinder (6.6).

5. The apparatus for preparing profiled polyester fibers according to claim 4, characterized in that, The counter-blown rectifier heating cylinder also includes a hot air pipe (6.3), which is located outside the outer cylinder (6.6) and connected to the hot air inlet.

6. The apparatus for preparing profiled polyester fibers according to claim 1, characterized in that, The vertical central axis of the spherical pressure stabilizing chamber (6.5) coincides with the central axis of the inner cylinder (6.7).

7. The apparatus for preparing profiled polyester fibers according to claim 6, characterized in that, The number of C-shaped grooves (6.1) is 20-24, and all C-shaped grooves (6.1) are evenly distributed around the vertical central axis of the spherical stabilizing chamber (6.5).

8. The apparatus for preparing profiled polyester fibers according to claim 7, characterized in that, Each C-shaped groove (6.1) has 8-10 compressed air outlets, arranged vertically with spacing between them. The spacing between two adjacent compressed air outlets is 10-12% of the length of the C-shaped groove (6.1). The length of the C-shaped groove (6.1) is 12-15% of the height of the inner cylinder (6.7). The cross-section of the C-shaped groove (6.1) is an arc with a central angle greater than or equal to 250° and less than or equal to 270°. The distance between the top of the C-shaped groove (6.1) and the inner cylinder (6.7) is 38-40% of the height of the inner cylinder (6.7). The distance between the C-shaped groove (6.1) and the cylinder wall of the inner cylinder (6.7) is 15-18% of the inner diameter of the inner cylinder (6.7).

9. The apparatus for preparing profiled polyester fibers according to claim 6, characterized in that, The central axis of the compressed air tube (6.2) coincides with the vertical central axis of the spherical pressure stabilizing chamber (6.5), and the compressed air tube (6.2) passes through the hot air inlet with a gap between it and the hot air inlet.

10. A method for preparing profiled polyester fibers, characterized in that, The apparatus for preparing profiled polyester fibers as described in any one of claims 1 to 9 is used.

11. The method for preparing profiled polyester fiber according to claim 10, characterized in that, The process flow is as follows: spinning metering device metering → component distribution extrusion → cooling → oiling → guide hook → diamond guide → pre-network → first comb guide → hot stretching → second comb guide → main networker → winding and forming. The spinning process parameters include: spinning temperature 294-296℃, cooling air pressure 18-21Pa, oil rack height 600-750mm, and oil content 1.03-1.25%; The winding process parameters include: hot stretching speed 3680-4350m / min, hot stretching temperature 110-120℃, winding speed 3600-4200m / min, pre-network pressure 0.07-0.09bar, and main network pressure 0.35-0.45bar. The specifications of the profiled polyester fiber are 75-83dtex / 144-196f, and the cross-sectional shape of the monofilament is cross-shaped, H-shaped or king-shaped; the breaking elongation of the profiled polyester fiber is 19.2-30.5%, the breaking elongation unevenness CV value is 3.8-6.2%, and the full roll rate is 96.6-99.1%.

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