Method for preparing high-quality polyester industrial yarn fiber

Abstract

A method for preparing a high-quality polyester industrial yarn fiber. A melt is extruded through a spinneret plate and then is slowly cooled by means of a slow cooler. The slow cooler comprises a hollow ring (11), an electromagnetic induction coil (8), a steel outer cylinder (9), a steel inner cylinder (10), a gas heating unit (14), a gas control unit (18), and an air compression station. A net-shaped porous structure is provided on the inner side wall (19) of the hollow ring (11); and a plurality of symmetrical small holes (20) are formed in the outer side wall of the hollow ring (11). The air compression station is connected to the gas heating unit (14) and the gas control unit (18) in sequence by means of a main air pipeline. The gas control unit (18) is communicated with the plurality of symmetrical small holes by means of a plurality of branch air pipelines. The electromagnetic induction coil (8) heats the steel outer cylinder (9) and the steel inner cylinder (10).

Description

A method for preparing high-quality polyester industrial yarn fiber Technical Field

[0001] The invention belongs to the technical field of fibers and relates to a method for preparing high-quality polyester industrial yarn fibers. Background Art

[0002] Due to their specialized applications, high-strength industrial yarns or high-modulus, low-shrinkage industrial yarns require excellent mechanical properties, characterized by high orientation and crystallinity in the polymer molecular structure. During the melt spinning process, the melt is extruded from the spinneret and cooled to form nascent fibers. This cooling process is accompanied by polymer recrystallization and rearrangement of the crystal lattice, so the quality of the cooling directly impacts the quality of the industrial yarn.

[0003] The melt reaches temperatures as high as 300°C when it is extruded from the spinneret, and the linear density of industrial yarn is high. Rapid cooling can affect the molecular structure, resulting in a so-called "skin-core" structure, and in severe cases, melt fracture. To allow the spun fiber to cool slowly, a slow cooling zone is often set between the spinneret and the cooling air.

[0004] The slow cooling zone currently used in industrial yarn production is a circular cavity with open ends, which has heating and heat preservation functions. The nascent fibers pass through the cavity to slowly cool down.

[0005] As shown in FIG1 , the slow cooling zone in the prior art mainly heats the aluminum plate 3 by the electric heating wire 2, so that the entire aluminum plate 3 is heated, and then heats the air in the circular cavity by heat radiation. This leads to the following problems:

[0006] First, heat transfer is slow, efficiency is low, and heat loss is large.

[0007] Second, the industrial yarn spinneret has a large area (Φ260mm), and heat radiates from the inner wall of the annular cavity to the center. The temperature of the outer ring of the spinneret is high, and the temperature of the inner ring close to the spinneret is low. As shown in Table 1, the temperature of the inner and outer rings of the spinneret is uneven, which affects the fluidity of the melt and the uniformity of the molecular chain orientation between the single fibers. The literature (Direct Spinning FDY44D Variety Development [D]. Suzhou University, 2005.) points out that different temperatures in the slow cooling zone affect the spinneret surface temperature and the stability of the yarn operation, which can easily cause hairy and broken yarns, and the fiber dyeing will have different degrees of stripes. The CV value of the linear density of polyester industrial yarn produced in the existing technology is ≤1.50%, the CV value of the single yarn strength is ≤1.00%, and the CV value of the single yarn diameter is ≤0.80%.

[0008] Table 1 Measured temperature values ​​of the center and outer ring of the Φ260mm spinneret

[0009] Third, in the prior art, the circular cavity in the slow-cooling zone is sealed from the component housing with insulation material at its upper end. As the filaments pass through this circular cavity at high speed, they carry away some air and heat. This is then passively replenished by new external cold air. This creates unstable airflow and temperature fields within the slow-cooling zone, prone to turbulence and increasing filament unevenness. This cold air replenishment in the prior art runs counter to the direction of fiber movement, hindering fiber movement and hindering improved fiber diameter uniformity.

[0010] Patent CN2063527U discloses a nitrogen-filled slow cooler, which is constructed by winding an electric heating wire around an outer cylinder, providing a small through-hole on the inner cylinder, and introducing nitrogen between the inner and outer cylinders. The electric heating wire heats the nitrogen to keep the filament bundle warm. The device has a complex structure, a high cost for introducing nitrogen, and cannot solve the uneven cooling of the filament bundles in the inner and outer rings of the spinneret.

[0011] Patent CN111910271B discloses a spinning device and a slow cooling device thereof. An air outlet window is provided on the inner wall of the slow cooling device. Hot air passes through the air outlet window to actively keep the filament bundle warm. The hot air flows out from the air outlet window on the inner wall. As the distance increases, the heat will decay. It also cannot solve the uneven cooling of the filament bundles in the inner and outer circles of the spinneret.

[0012] Patent CN107906684B discloses a spinning method for extending the clearing cycle of special-section fiber production. Special insulation plates are added to the slow cooling zone to slow down the diffusion of heat generated by the filament bundle, thereby insulating the nascent fibers. This device is highly dependent on the insulation material. If the insulation material fails, the insulation effect will deteriorate.

[0013] With the development of high-end industrial yarn products, customers are paying more and more attention to physical properties of industrial yarn such as dyeing uniformity, color difference between batches, single yarn linear density CV value, and single fiber strength.

[0014] Therefore, it is of great significance to provide a method for preparing high-quality polyester industrial yarn fibers by improving the slow cooling device.

[0015] Summary of the Invention

[0016] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing high-quality polyester industrial yarn fibers.

[0017] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0018] A method for preparing high-quality polyester industrial yarn fibers, comprising: extruding a melt through a spinneret, followed by slow cooling in a slow cooler, cooling in a windless zone, cooling with side air, oiling, stretching, shaping, web-forming, and winding to produce high-quality polyester industrial yarn fibers;

[0019] The slow cooler includes a hollow ring, an electromagnetic induction coil, a heat insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station and a PC terminal;

[0020] The inner wall of the hollow ring is provided with a mesh-like porous structure, and the outer wall is provided with a plurality of small holes symmetrical about the center of the hollow ring;

[0021] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to multiple symmetrical small holes through multiple branch air pipelines. The gas control unit is electrically connected to the PC end. The PC end sends signals to drive the gas control unit to control the gas flow and temperature, and display them in real time.

[0022] Specifically, the air delivered from the air compression station enters the gas heating unit through the main air duct for heating, and the heated hot air enters the gas control unit through the main air duct. The gas control unit includes temperature control and flow control. The temperature control is used to control the temperature of the hot air, and the PC sends a signal to adjust the heating unit to ensure that the air temperature reaches the set process temperature. The flow control is used to control the amount of hot air entering the hollow ring, and the PC realizes the opening adjustment of the control valve. After passing through the gas control unit, the hot air is connected to the hollow ring through (the number is greater than or equal to 2) branch air ducts. There are multiple small holes (the same number as the branch air ducts out of the gas control unit) symmetrically distributed on the circumferential surface of the outer ring of the hollow ring, and the branch air ducts are connected to the small holes by threads or tight hoops;

[0023] The top of the steel outer cylinder is connected to the spinneret through a hollow ring;

[0024] A high-temperature resistant heat-insulating block is provided at the top of the steel inner cylinder; the steel inner cylinder is fixedly connected to the center of the spinneret through the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret;

[0025] The hollow ring is the same height as the high-temperature resistant insulation block, the steel outer cylinder is the same height as the steel inner cylinder, and the cross-sectional area between the inner and outer walls of the steel outer cylinder and the inner and outer walls of the steel inner cylinder are the same (i.e., the area of ​​the ring formed between the outer diameter and inner diameter of the steel outer cylinder and the steel inner cylinder is the same);

[0026] The electromagnetic induction coil is sheathed on the outer surface of the steel outer cylinder through a heat insulation layer. The external power supply is electrically connected to the electromagnetic induction coil through an electronic oscillator, and the PC end is electrically connected to the electronic oscillator through a controller.

[0027] An external power supply applies an oscillating current to the induction coil through an electronic oscillator, causing the electrons in the steel outer and inner cylinders to oscillate at high frequencies under the action of the electromagnetic field, generating heat. The electronic oscillator is connected to a controller, which controls the on and off of the current to cause the electronic oscillator to generate a high-frequency current in the electromagnetic induction coil. The current in the electromagnetic induction coil is controlled through the PC, thereby controlling the temperature of the steel outer and inner cylinders.

[0028] Specifically, according to the electromagnetic principle, when an alternating current passes through a coil, an alternating magnetic field is generated around the coil. Assuming the magnetic flux is Φ, the number of coil turns is N, and the induced electromotive force is e, the calculation formula for the induced electromotive force is:

[0029] The magnetic flux Φ changes sinusoidally, Φ m is the maximum value of magnetic flux, thus: Φ=Φ m sin(ωt) (2);

[0030] From (1) and (2), and ω=2πf, we can get

[0031] Then the effective value E of the induced electromotive force is:

[0032] The effective value of the induced current generated by the induced electromotive force in the steel cylinder is I. According to Joule's law, the heat Q generated by electromagnetic induction is: Q = I 2 Rt (5);

[0033] The magnitude of the induced current is determined by the induced electromotive force and the impedance generated in the heated material. According to Ohm's law, the induced current I can be obtained as:

[0034] Where Φ=BS, B is the magnetic induction intensity, S is the area, P is the resistivity, and L is the length of the resistor, from which we can get:

[0035] From formula (7), we can see that the heat Q generated by electromagnetic induction is related to the external power frequency f, the number of turns N of the coil, the magnetic induction intensity B, the cross-sectional area S of the steel cylinder, the resistivity P of the steel cylinder, the length L of the steel cylinder, and the time t. For the same magnetic induction coil, f, N, and B are the same, and the resistivity P of steel cylinders made of the same material is the same. Therefore, the heat generated by electromagnetic induction in the outer steel cylinder and the inner steel cylinder is mainly related to the cross-sectional area S and length L of the steel cylinder through which the magnetic flux lines pass in the electromagnetic induction magnetic field.

[0036] According to the calculation formula of heat Q and temperature T: Q=cmΔT (8);

[0037] Where c is the specific heat of the steel cylinder, and m is the mass of the steel cylinder. The relationship between heat and temperature can be obtained. In order to make the temperature generated by the outer steel cylinder and the inner steel cylinder the same, it is only necessary that the cross-sectional area and height of the outer steel cylinder and the inner steel cylinder are the same.

[0038] From the above derivation, we can know that the temperature of the steel outer cylinder and the steel inner cylinder is related to the frequency f of the oscillating current. The controller controls the on and off of the current to make the electronic oscillator generate a high-frequency changing current in the electromagnetic induction coil. This process can be achieved through the PC end to control the current frequency in the electromagnetic induction coil and realize the temperature control of the steel outer cylinder and the steel inner cylinder.

[0039] The spinneret holes on the spinneret are located between the steel outer cylinder and the steel inner cylinder.

[0040] As the preferred technical solution:

[0041] As described above, the outer diameter of the hollow ring is 280-290 mm, and the inner diameter is 245-260 mm; the outer diameter of the steel outer cylinder is 250-265 mm, and the inner diameter is 245-260 mm. The outer diameter of the hollow ring is 25-30 mm larger than the outer diameter of the steel outer cylinder, mainly considering that the steel outer cylinder is covered with a 12.5-15 mm thick insulation layer; the outer diameter of the steel inner cylinder is 80-122 mm, and the inner diameter is 62-110 mm; the height of the electromagnetic induction coil is 280-320 mm, the height of the steel outer cylinder is 280-320 mm, the height of the steel inner cylinder is 280-320 mm, and the height of the hollow ring is 10-15 mm.

[0042] As described above, in the method for preparing high-quality polyester industrial yarn fibers, the slow cooler also includes an insulating shell, which is wrapped around the outer surface of the hollow ring and the steel outer cylinder; the electromagnetic induction coil is located between the steel outer cylinder and the insulating shell, and the insulating shell can reduce heat loss.

[0043] As described above, a method for preparing high-quality polyester industrial yarn fibers comprises a hollow ring mesh porous structure consisting of 6 to 8 rows of circular holes, with adjacent rows of circular holes arranged in a staggered manner; the aperture of the circular holes in the mesh porous structure is 1 to 2 mm, the horizontal spacing between the centers of two adjacent rows of circular holes is 1.5 to 2 mm, and the vertical spacing between the centers of two adjacent circular holes in each row of circular holes is 4 to 6 mm.

[0044] As described above, in a method for preparing high-quality polyester industrial yarn fibers, the longitudinal section of the hollow ring along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 40° to 60°. The purpose is to make the angle between the hot air outlet direction and the yarn bundle 40° to 60°, so that the hot air can stretch the yarn bundle.

[0045] In the method for preparing high-quality polyester industrial yarn fibers as described above, a filter is provided at the entrance of the small hole to filter the gas entering the hollow ring, thereby preventing the gas from polluting the air in the slow cooling zone and affecting the cooling effect of the nascent fiber.

[0046] A method for preparing high-quality polyester industrial yarn fiber as described in any of the above items, wherein the melt is a polyester melt, and the intrinsic viscosity of the polyester melt is 1.10-1.15 dL / g; the spinneret diameter is 240-260 mm, the spinneret holes are arranged in 6-8 concentric circles, the diameter of the circle containing the center of the innermost circle of spinneret holes is 130-135 mm, and the spinneret hole diameter is 0.5-0.8 mm.

[0047] The process parameters of the method for preparing high-quality polyester industrial yarn fiber are as follows: the temperature of the gas controlled by the gas control unit is 280-310°C, the flow rate is 1.0-4.0 g / s; the temperature of the steel outer cylinder is 280-310°C, and the temperature of the steel inner cylinder is 280-310°C; the cooling air speed is 0.5-0.6 m / min, the cooling air temperature is 20-30°C, the stretch ratio is 5-6, and the network pressure is 0.30-0.40 MPa;

[0048] The amount of hot air entering the annular cavity can be adjusted by the gas control unit, and the amount of hot air taken away cannot be directly measured. Under the same process conditions, the amount of hot air flow entering is adjusted by the gas control unit, and then the filament bundle under this condition is selected to obtain the fiber morphology through scanning electron microscopy testing, and then the fiber diameter is measured by Image software, the fiber diameter distribution is calculated, and the optimal amount of hot air flow entering is selected. The specific calculation method is: under a certain amount of hot air flow entering, the diameters of multiple (50 to 100) monofilaments under this condition are measured, and the diameter distribution can be obtained. The air flow rate under the condition with the largest proportion in the diameter range of 1.0 to 1.2 mm can be selected. The present invention selects a flow rate of 1.0 to 4.0 g / s, which is obtained based on such multiple tests.

[0049] The high-quality polyester industrial yarn fiber is prepared according to the above method. The high-quality polyester industrial yarn fiber is evenly dyed with a dyeing grade of 4.0 to 4.5. The dyeing uniformity is tested with reference to GB T 6508-2015 polyester filament dyeing uniformity test method. The linear density is 3350 to 3450 dtex, the linear density CV value is ≤1.20%, the single yarn strength is ≥0.7N, the single yarn strength CV value is ≤0.80%, the single yarn diameter is 1.0 to 1.2 mm, and the single yarn diameter CV value is ≤0.50%.

[0050] In the above-mentioned method for preparing high-quality polyester industrial yarn fibers, the high-temperature resistant insulation block is made of a heat-resistant silicone resin, with reference to the heat-resistant silicone resin in patent CN105273197A.

[0051] The principles of the present invention are as follows:

[0052] The basic principle of electromagnetic induction heating is to place the conductor to be heated in a closed loop of a coil. Simultaneously, an alternating current is passed through the coil, generating an alternating magnetic field with the same frequency as the current. According to the principle of electromagnetic induction, the electrons within the conductor in the magnetic field oscillate at a high frequency under the influence of the alternating field, causing the conductor to generate a large amount of heat.

[0053] The slow cooling device of the present invention houses a steel outer and inner cylinder within a closed coil. Electromagnetic induction heats the two steel conductors, raising their temperature to a set temperature. This insulates the spun fibers and allows them to cool slowly. Heat generated by the outer cylinder radiates toward the core through its inner wall, while heat generated by the inner cylinder radiates outward through its outer wall. This allows the filaments extruded from the inner and outer spinnerets to cool synchronously, avoiding the uneven cooling, orientation, and stress between individual filaments caused by temperature differences between the inner and outer spinnerets, as in the prior art.

[0054] In the prior art, the slow cooling device and the components are sealed with insulation material, thus forming a "∩"-shaped structure. At this time, the hot air in the cavity is carried away by the filaments running downward at high speed, and the surrounding cold air will passively come in to replenish it. On the one hand, turbulence will be generated in the cavity, affecting the uniformity of the raw fiber strands. On the other hand, the passive replenishment of the cold air causes the heat in the cavity to exchange heat with cold, resulting in an unstable temperature field change in the cavity, which affects the cooling uniformity between the filaments. The present invention adds a hollow ring to replace the insulation material. The gas is heated to the process temperature by a gas heating unit and transported into the hollow ring through an air duct. The inner wall of the hollow ring is a uniform porous mesh structure. The hot air is actively replenished into the annular cavity between the steel outer cylinder and the steel inner cylinder through the hollow ring. The filaments carry away a certain amount of hot air, and the annular cavity will be replenished with hot air. The amount of hot air replenished is greater than the amount of hot air taken away, avoiding the replenishment of external cold air, forming a stable airflow field and temperature field in the annular cavity, reducing the uneven strands and uneven cooling of the filaments caused by unstable shaking of the filaments.

[0055] The radial longitudinal section of the hollow ring is two identical inverted right-angled trapezoids, with the angle between the long base and the hypotenuse of the inverted right-angled trapezoid being 40° to 60°. This makes the angle between the hot air outlet direction and the filament bundle 40° to 60°, and the hot air flow direction forms a certain angle with the fiber running direction, avoiding the hot air from acting vertically on the filaments and reducing the obstruction of the hot air to the fiber movement. At the same time, the downward flow of the hot air can also play a role in micro-stretching the filament bundle, thereby facilitating the improvement of the uniformity of the fiber strands. However, the solution designed in patent CN111910271B gradually increases the amount of gas supplied into the hollow chamber along the direction of the primary fiber passing through, that is, the hot air flow rate is small near the spinneret and large away from the spinneret. When the filament bundle is running downward, the high flow air flow below the slow cooling zone will hinder the movement of the filaments, so this patent does not play a micro-stretching role. Beneficial effects:

[0056] (1) The present invention provides a method for preparing high-quality polyester industrial yarn fibers, which uses a double-layer metal sleeve and heats it by electromagnetic induction for use in a slow cooling device, so that the slow cooling device can simultaneously insulate the yarn bundle extruded from the spinneret from the outside to the inside and from the inside to the outside, that is, the inner and outer ring yarn bundles of the spinneret can be synchronously insulated and cooled, thereby solving the problem of uneven cooling caused by the large area of ​​the industrial yarn spinneret and the long distance between the inner and outer ring yarn bundles, thereby improving the uniformity of orientation and stress between the single yarns of the high-quality polyester industrial yarn fibers, and being beneficial to improving the strength and dyeing uniformity of the high-quality polyester industrial yarn fibers;

[0057] (2) The electromagnetic heating of the present invention adopts non-contact heating, which has the characteristics of fast heating and can quickly heat up, thus avoiding the occurrence of abnormalities in the bottom yarn of the yarn cake. During the spinning and cleaning process, the temperature of the spinneret surface will drop due to operations such as closing the metering pump, spraying silicone oil, and scraping the plate. The traditional electric heating method takes a certain amount of time to reach the set temperature, which will cause abnormalities in the bottom yarn of the yarn cake and affect the quality of the yarn.

[0058] (3) The present invention adopts hollow rings, gas heating units, gas control units and air compression stations to actively replenish hot air. The flow direction of the hot air is at a certain angle to the fiber running direction, so that a stable airflow field and temperature field are formed between the double-layer metal sleeves, which reduces the obstruction of the airflow to the filament bundle in the existing technology and is conducive to improving the uniformity of the fiber strands. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG1 is a schematic diagram of a slow cooling device in the prior art;

[0060] FIG2 is a schematic diagram of a slow cooling device according to the present invention;

[0061] FIG3 is a bottom view of the slow cooling device of the present invention;

[0062] FIG4 is a bottom view schematic diagram of the hollow ring of the present invention;

[0063] FIG5 is a longitudinal sectional view of the hollow ring of the present invention along the radial direction;

[0064] FIG6 is a schematic diagram of an inverted right-angled trapezoid;

[0065] FIG7 is a bottom view of the steel outer cylinder and the steel inner cylinder of the present invention;

[0066] Among them: 1-spinning assembly, 2-electric heating wire, 3-aluminum plate, 4-filament bundle, 8-electromagnetic induction coil, 9-steel outer cylinder, 10-steel inner cylinder, 11-hollow ring, 12-thermal insulation shell, 13-thermal insulation layer, 14-gas heating unit, 15-electronic oscillator, 16-controller, 17-PC terminal, 18-gas control unit, 19-inner wall of hollow ring, 20-small hole. DETAILED DESCRIPTION

[0067] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, 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 equally within the scope limited by the appended claims of the application.

[0068] The test methods / standards involved in the examples are as follows:

[0069] Dyeing uniformity: Tested in accordance with GB T 6508-2015 Test method for dyeing uniformity of polyester filament;

[0070] Linear density: Tested in accordance with GB T 14343-2008 Test method for linear density of chemical fiber filaments and GB T 16604-2017 Test method for polyester industrial filaments;

[0071] Linear density CV value: Tested in accordance with GB T 14343-2008 Test method for linear density of chemical fiber filaments;

[0072] Monofilament strength: Tested in accordance with GB T 14337-2008 Test method for tensile properties of chemical staple fibers;

[0073] Single yarn strength CV value: Tested in accordance with GB T 14337-2008 Test method for tensile properties of chemical staple fibers.

[0074] Example 1

[0075] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0076] As shown in Figures 1 to 3, a polyester melt with an intrinsic viscosity of 1.10 dL / g is extruded through a spinneret with a diameter of 240 mm in a spinning assembly 1 and then subjected to slow cooling in a slow cooler, cooling in a windless zone, and side-blown cooling. The resulting filament bundle 4 is then subjected to oiling, stretching, shaping, networking, and winding to produce high-quality polyester industrial yarn fibers.

[0077] The slow cooler includes a hollow ring 11, an electromagnetic induction coil 8, a heat insulation layer 13, a steel outer cylinder 9, a steel inner cylinder 10, an external power supply, an electronic oscillator 15, a controller 16, a gas heating unit 14, a gas control unit 18, an air compression station, a PC terminal 17 and a heat insulation shell 12;

[0078] As shown in Figures 4 to 7, the outer diameter of the hollow ring 11 is 280 mm, the inner diameter is 245 mm, and the height is 10 mm; the longitudinal section of the hollow ring 11 along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 40°; a mesh porous structure is provided on the inner side wall of the hollow ring 11, and the mesh porous structure consists of 6 rows of circular holes, and any two adjacent rows of circular holes are staggered; the aperture of the circular holes in the mesh porous structure is 1 mm, and the spacing between the horizontal lines where the centers of the two adjacent rows of circular holes are located is 1.5 mm. In each row of circular holes, the spacing between the vertical lines where the centers of the two adjacent circular holes are located is 4 mm; the outer side wall of the hollow ring 11 is provided with two symmetrical small holes 20, and a filter screen is provided at the entrance of the small hole 20;

[0079] The outer diameter of the steel outer cylinder 9 is 250 mm, the inner diameter is 245 mm, and the height of the steel outer cylinder 9 is 280 mm. The top of the steel outer cylinder 9 is connected to the spinneret through a hollow ring 11.

[0080] The heat-insulating shell 12 is wrapped around the outer surface of the hollow ring 11 and the steel outer cylinder 9;

[0081] The outer diameter of the steel inner cylinder 10 is 80 mm, the inner diameter is 62.65 mm, and the height of the steel inner cylinder 10 and the outer cylinder 9 are the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder 10 and is the same height as the hollow ring 11. The steel inner cylinder 10 is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0082] The spinneret holes are located between the outer steel cylinder 9 and the inner steel cylinder 10. The spinnerets are arranged in 6 concentric circles. The distance between the centers of two adjacent circles of spinnerets is 5 mm. The diameter of the circle containing the center of the innermost circle of spinnerets is 130 mm. The diameter of all spinnerets is 0.5 mm.

[0083] An electromagnetic induction coil 8 with a height of 280 mm is enclosed on the outer surface of a steel outer cylinder 9 via a heat-insulating layer 13. The electromagnetic induction coil 8 is located between the steel outer cylinder 9 and the heat-insulating outer shell 12. An external power supply is electrically connected to the electromagnetic induction coil 8 via an electronic oscillator 15, and a PC is electrically connected to the electronic oscillator 15 via a controller 16.

[0084] The air compression station is connected to the gas heating unit 14 and the gas control unit 18 in sequence through the main air pipeline. The gas control unit 18 is connected to two symmetrical small holes through two branch air pipelines. The gas control unit 18 is electrically connected to the PC terminal 17. The PC terminal 17 sends signals to drive the gas control unit 18 to control the gas flow and temperature and display them in real time.

[0085] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit 18 is 280°C and the flow rate is 1g / s; the temperature of the steel outer cylinder 9 is 280°C, and the temperature of the steel inner cylinder 10 is 280°C; the cooling air speed is 0.5m / min, the cooling air temperature is 20°C, the stretch ratio is 5, and the network pressure is 0.3MPa;

[0086] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4, a linear density of 3350 dtex, a linear density CV value of 1.1%, a single yarn strength of 0.7 N, a single yarn strength CV value of 0.8%, a single yarn diameter of 1 mm, and a single yarn diameter CV value of 0.5%.

[0087] Example 2

[0088] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0089] The polyester melt with an intrinsic viscosity of 1.11 dL / g is extruded through a spinneret with a diameter of 240 mm and then subjected to slow cooling in a slow cooler, cooling in a windless zone, side-blown cooling, oiling, stretching, shaping, web-forming, and winding to produce high-quality polyester industrial yarn.

[0090] The slow cooler includes a hollow ring, an electromagnetic induction coil, a thermal insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station, a PC terminal and a thermal insulation shell;

[0091] The outer diameter of the hollow ring is 284mm, the inner diameter is 248mm, and the height is 11mm. The longitudinal section of the hollow ring along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 45°. The inner wall of the hollow ring is provided with a mesh porous structure, which consists of 7 rows of circular holes, and any two adjacent rows of circular holes are staggered. The aperture of the circular holes in the mesh porous structure is 1.2mm, and the spacing between the horizontal lines of the centers of two adjacent rows of circular holes is 1.6mm. In each row of circular holes, the spacing between the vertical lines of the centers of two adjacent circular holes is 4.4mm. The outer wall of the hollow ring is provided with 4 symmetrical small holes, and a filter screen is provided at the entrance of the small holes.

[0092] The outer diameter of the steel outer cylinder is 254 mm, the inner diameter is 248 mm, and the height of the steel outer cylinder is 285 mm. The top of the steel outer cylinder is connected to the spinneret through a hollow ring.

[0093] The heat-insulating shell is wrapped around the outer surface of the hollow ring and the steel outer cylinder;

[0094] The outer diameter of the steel inner cylinder is 86 mm, the inner diameter is 66.21 mm, and the height of the steel inner cylinder and the outer cylinder is the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder at the same height as the hollow ring. The steel inner cylinder is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0095] The spinneret holes are located between the outer and inner steel cylinders. The spinnerets are arranged in six concentric circles, with the centers of the spinnerets in two adjacent circles spaced 5 mm apart. The diameter of the circle containing the centers of the innermost spinneret holes is 130 mm, and the diameter of all spinneret holes is 0.6 mm.

[0096] An electromagnetic induction coil with a height of 290 mm is wrapped around the outer surface of the steel outer cylinder through a heat-insulating layer. The electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell. An external power supply is electrically connected to the electromagnetic induction coil through an electronic oscillator, and a PC is electrically connected to the electronic oscillator through a controller.

[0097] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to four symmetrical small holes through four branch air pipelines. The gas control unit is electrically connected to the PC end, and the PC end sends signals to drive the gas control unit to control the gas flow and temperature and display them in real time.

[0098] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit is 285°C and the flow rate is 1.5g / s; the temperature of the steel outer cylinder is 285°C, and the temperature of the steel inner cylinder is 285°C; the cooling air speed is 0.52m / min, the cooling air temperature is 22°C, the stretch ratio is 5.2, and the network pressure is 0.32MPa;

[0099] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4, a linear density of 3380 dtex, a linear density CV value of 1%, a single yarn strength of 0.72 N, a single yarn strength CV value of 0.76%, a single yarn diameter of 1.05 mm, and a single yarn diameter CV value of 0.45%.

[0100] Example 3

[0101] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0102] The polyester melt with an intrinsic viscosity of 1.12 dL / g is extruded through a spinneret with a diameter of 240 mm and then subjected to slow cooling in a slow cooler, cooling in a windless zone, side-blown cooling, oiling, stretching, shaping, web-forming, and winding to produce high-quality polyester industrial yarn.

[0103] The slow cooler includes a hollow ring, an electromagnetic induction coil, a thermal insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station, a PC terminal and a thermal insulation shell;

[0104] The outer diameter of the hollow ring is 284mm, the inner diameter is 250mm, and the height is 12mm. The longitudinal section of the hollow ring along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 50°. The inner wall of the hollow ring is provided with a mesh porous structure, which consists of 8 rows of circular holes, and any two adjacent rows of circular holes are staggered. The aperture of the circular holes in the mesh porous structure is 1.4mm, and the spacing between the horizontal lines of the centers of two adjacent rows of circular holes is 1.7mm. In each row of circular holes, the spacing between the vertical lines of the centers of two adjacent circular holes is 4.8mm. The outer wall of the hollow ring is provided with four symmetrical small holes, and a filter screen is provided at the entrance of the small holes.

[0105] The outer diameter of the steel outer cylinder is 258 mm, the inner diameter is 250 mm, and the height of the steel outer cylinder is 290 mm; the top of the steel outer cylinder is connected to the spinneret through a hollow ring;

[0106] The heat-insulating shell is wrapped around the outer surface of the hollow ring and the steel outer cylinder;

[0107] The outer diameter of the steel inner cylinder is 103 mm, the inner diameter is 80.90 mm, and the height of the steel inner cylinder and the outer cylinder is the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder at the same height as the hollow ring. The steel inner cylinder is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0108] The spinneret holes are located between the outer and inner steel cylinders. The spinnerets are arranged in six concentric circles, with the centers of the spinnerets in two adjacent circles spaced 5 mm apart. The diameter of the circle containing the centers of the innermost spinnerets is 130 mm, and the diameter of all spinnerets is 0.65 mm.

[0109] An electromagnetic induction coil with a height of 300 mm is wrapped around the outer surface of the steel outer cylinder through a heat-insulating layer. The electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell. An external power supply is electrically connected to the electromagnetic induction coil through an electronic oscillator, and a PC is electrically connected to the electronic oscillator through a controller.

[0110] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to four symmetrical small holes through four branch air pipelines. The gas control unit is electrically connected to the PC end, and the PC end sends signals to drive the gas control unit to control the gas flow and temperature and display them in real time.

[0111] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit is 290°C and the flow rate is 2g / s; the temperature of the steel outer cylinder is 290°C, and the temperature of the steel inner cylinder is 290°C; the cooling air speed is 0.54m / min, the cooling air temperature is 24°C, the stretch ratio is 5.4, and the network pressure is 0.34MPa;

[0112] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4.5, a linear density of 3400 dtex, a linear density CV value of 0.9%, a single yarn strength of 0.75N, a single yarn strength CV value of 0.7%, a single yarn diameter of 1.1mm, and a single yarn diameter CV value of 0.38%.

[0113] Example 4

[0114] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0115] The polyester melt with an intrinsic viscosity of 1.13 dL / g is extruded through a spinneret with a diameter of 260 mm and then subjected to slow cooling in a slow cooler, cooling in a windless zone, side-blown cooling, oiling, stretching, shaping, web-forming, and winding to produce high-quality polyester industrial yarn.

[0116] The slow cooler includes a hollow ring, an electromagnetic induction coil, a thermal insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station, a PC terminal and a thermal insulation shell;

[0117] The outer diameter of the hollow ring is 286mm, the inner diameter is 255mm, and the height is 13mm. The longitudinal section of the hollow ring along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 55°. The inner wall of the hollow ring is provided with a mesh porous structure, which consists of 8 rows of circular holes, and any two adjacent rows of circular holes are staggered. The aperture of the circular holes in the mesh porous structure is 1.6mm, and the spacing between the horizontal lines of the centers of two adjacent rows of circular holes is 1.8mm. In each row of circular holes, the spacing between the vertical lines of the centers of two adjacent circular holes is 5.2mm. The outer wall of the hollow ring is provided with 8 symmetrical small holes, and a filter is provided at the entrance of the small holes.

[0118] The outer diameter of the steel outer cylinder is 260 mm, the inner diameter is 255 mm, and the height of the steel outer cylinder is 300 mm; the top of the steel outer cylinder is connected to the spinneret through a hollow ring;

[0119] The heat-insulating shell is wrapped around the outer surface of the hollow ring and the steel outer cylinder;

[0120] The outer diameter of the steel inner cylinder is 103.32 mm, the inner diameter is 90 mm, and the height of the steel inner cylinder and the outer cylinder is the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder at the same height as the hollow ring. The steel inner cylinder is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0121] The spinneret holes are located between the outer and inner steel cylinders. The spinnerets are arranged in eight concentric circles, with the centers of two adjacent circles of spinnerets spaced 5 mm apart. The diameter of the circle containing the center of the innermost circle of spinnerets is 135 mm, and the diameter of all spinnerets is 0.7 mm.

[0122] An electromagnetic induction coil with a height of 310 mm is wrapped around the outer surface of the steel outer cylinder through a heat-insulating layer. The electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell. An external power supply is electrically connected to the electromagnetic induction coil via an electronic oscillator, and a PC is electrically connected to the electronic oscillator via a controller.

[0123] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to eight symmetrical small holes through eight branch air pipelines. The gas control unit is electrically connected to the PC end, and the PC end sends signals to drive the gas control unit to control the gas flow and temperature, and display them in real time.

[0124] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit is 295°C and the flow rate is 2.5g / s; the temperature of the steel outer cylinder is 295°C, and the temperature of the steel inner cylinder is 295°C; the cooling air speed is 0.56m / min, the cooling air temperature is 26°C, the stretch ratio is 5.6, and the network pressure is 0.36MPa;

[0125] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4.5, a linear density of 3410 dtex, a linear density CV value of 1.1%, a single yarn strength of 0.76 N, a single yarn strength CV value of 0.63%, a single yarn diameter of 1.12 mm, and a single yarn diameter CV value of 0.42%.

[0126] Example 5

[0127] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0128] The polyester melt with an intrinsic viscosity of 1.14 dL / g is extruded through a spinneret with a diameter of 260 mm and then subjected to slow cooling in a slow cooler, cooling in a windless zone, side-blown cooling, oiling, stretching, shaping, web-forming, and winding to produce high-quality polyester industrial yarn.

[0129] The slow cooler includes a hollow ring, an electromagnetic induction coil, a thermal insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station, a PC terminal and a thermal insulation shell;

[0130] The outer diameter of the hollow ring is 290mm, the inner diameter is 258mm, and the height is 14mm. The longitudinal section of the hollow ring along the radial direction is two identical inverted right-angled trapezoids, and the angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 58°. The inner wall of the hollow ring is provided with a mesh porous structure, which consists of 8 rows of circular holes, and any two adjacent rows of circular holes are staggered. The aperture of the circular holes in the mesh porous structure is 1.8mm, and the spacing between the horizontal lines of the centers of two adjacent rows of circular holes is 1.9mm. In each row of circular holes, the spacing between the vertical lines of the centers of two adjacent circular holes is 5.6mm. The outer wall of the hollow ring is provided with 8 symmetrical small holes, and a filter is provided at the entrance of the small holes.

[0131] The outer diameter of the steel outer cylinder is 263 mm, the inner diameter is 258 mm, and the height of the steel outer cylinder is 310 mm. The top of the steel outer cylinder is connected to the spinneret through a hollow ring.

[0132] The heat-insulating shell is wrapped around the outer surface of the hollow ring and the steel outer cylinder;

[0133] The outer diameter of the steel inner cylinder is 112.27 mm, the inner diameter is 100 mm, and the height of the steel inner cylinder and the outer cylinder are the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder and is the same height as the hollow ring. The steel inner cylinder is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0134] The spinneret holes are located between the outer and inner steel cylinders. The spinnerets are arranged in eight concentric circles, with the centers of two adjacent circles of spinnerets spaced 5 mm apart. The diameter of the circle containing the center of the innermost circle of spinnerets is 135 mm, and the diameter of all spinnerets is 0.75 mm.

[0135] An electromagnetic induction coil with a height of 315 mm is wrapped around the outer surface of the steel outer cylinder through a heat-insulating layer. The electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell. An external power supply is electrically connected to the electromagnetic induction coil via an electronic oscillator, and a PC is electrically connected to the electronic oscillator via a controller.

[0136] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to eight symmetrical small holes through eight branch air pipelines. The gas control unit is electrically connected to the PC end, and the PC end sends signals to drive the gas control unit to control the gas flow and temperature, and display them in real time.

[0137] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit is 300°C and the flow rate is 3g / s; the temperature of the steel outer cylinder is 300°C, and the temperature of the steel inner cylinder is 300°C; the cooling air speed is 0.58m / min, the cooling air temperature is 28°C, the stretch ratio is 5.8, and the network pressure is 0.38MPa;

[0138] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4, a linear density of 3430 dtex, a linear density CV value of 1.2%, a single yarn strength of 0.78 N, a single yarn strength CV value of 0.65%, a single yarn diameter of 1.15 mm, and a single yarn diameter CV value of 0.35%.

[0139] Example 6

[0140] A method for preparing high-quality polyester industrial yarn fiber, the specific process is as follows:

[0141] The polyester melt with an intrinsic viscosity of 1.15 dL / g is extruded through a 260mm diameter spinneret in the spinning assembly and then subjected to slow cooling in a slow cooler, a windless zone, and side-blown cooling. The resulting filaments are then oiled, stretched, shaped, webbed, and wound to produce high-quality polyester industrial yarn.

[0142] The slow cooler includes a hollow ring, an electromagnetic induction coil, a thermal insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, an air compression station, a PC terminal and a thermal insulation shell;

[0143] The hollow ring has an outer diameter of 290mm, an inner diameter of 260mm, and a height of 15mm. The radial longitudinal section of the hollow ring is two identical inverted right-angled trapezoids, with the angle between the long base and the hypotenuse of the inverted right-angled trapezoid being 60°. The inner wall of the hollow ring is provided with a mesh-like porous structure, which consists of 8 rows of circular holes, with any two adjacent rows of circular holes staggered. The aperture of the circular holes in the mesh-like porous structure is 2mm, the horizontal line spacing between the centers of two adjacent rows of circular holes is 2mm, and the vertical line spacing between the centers of two adjacent circular holes in each row is 6mm. The outer wall of the hollow ring is provided with 8 symmetrical small holes, and a filter screen is provided at the entrance of the small holes.

[0144] The outer diameter of the steel outer cylinder is 265 mm, the inner diameter is 260 mm, and the height of the steel outer cylinder is 320 mm. The top of the steel outer cylinder is connected to the spinneret through a hollow ring.

[0145] The heat-insulating shell is wrapped around the outer surface of the hollow ring and the steel outer cylinder;

[0146] The outer diameter of the steel inner cylinder is 121.35 mm, the inner diameter is 110 mm, and the height of the steel inner cylinder and the outer cylinder is the same. A high-temperature resistant heat-insulating block made of heat-resistant silicone resin is provided at the top of the steel inner cylinder at the same height as the hollow ring. The steel inner cylinder is fixedly connected to the center of the spinneret via the high-temperature resistant heat-insulating block, and the high-temperature resistant heat-insulating block is threadedly connected to the spinneret.

[0147] The spinneret holes are located between the outer and inner steel cylinders. The spinnerets are arranged in eight concentric circles, with the centers of two adjacent circles of spinnerets spaced 5 mm apart. The diameter of the circle containing the centers of the innermost circle of spinnerets is 135 mm, and the diameter of all spinnerets is 0.8 mm.

[0148] An electromagnetic induction coil with a height of 320 mm is wrapped around the outer surface of the steel outer cylinder through a heat-insulating layer. The electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell. An external power supply is electrically connected to the electromagnetic induction coil through an electronic oscillator, and a PC is electrically connected to the electronic oscillator through a controller.

[0149] The air compression station is connected to the gas heating unit and gas control unit in sequence through the main air pipeline. The gas control unit is connected to eight symmetrical small holes through eight branch air pipelines. The gas control unit is electrically connected to the PC end, and the PC end sends signals to drive the gas control unit to control the gas flow and temperature, and display them in real time.

[0150] Process parameters for preparing high-quality polyester industrial yarn fibers: The gas temperature controlled by the gas control unit is 310°C and the flow rate is 4g / s; the temperature of the steel outer cylinder is 310°C, and the temperature of the steel inner cylinder is 310°C; the cooling air speed is 0.6m / min, the cooling air temperature is 30°C, the stretch ratio is 6, and the network pressure is 0.4MPa;

[0151] The high-quality polyester industrial yarn fiber produced has a dyeing evenness grade of 4.5, a linear density of 3450 dtex, a linear density CV value of 1.2%, a single yarn strength of 0.8N, a single yarn strength CV value of 0.78%, a single yarn diameter of 1.2mm, and a single yarn diameter CV value of 0.46%.

[0152] It should be noted that, due to the influence of factors such as processing accuracy in the actual processing process, the outer diameter and inner diameter of the steel outer cylinder and the outer diameter and inner diameter of the steel inner cylinder in the above embodiment of the present invention do not retain significant figures after the decimal point for integers, and retain two significant figures after the decimal point for non-integers based on rounding.

Claims

1. A method for preparing high-quality polyester industrial yarn fibers, wherein the melt is extruded through a spinneret and then subjected to slow cooling in a slow cooling device, cooling in a windless zone, cooling with side blowing, oiling, stretching, shaping, networking, and winding to form high-quality polyester industrial yarn fibers, characterized in that: The slow cooler includes a hollow ring, an electromagnetic induction coil, a heat insulation layer, a steel outer cylinder, a steel inner cylinder, an external power supply, an electronic oscillator, a controller, a gas heating unit, a gas control unit, a compression station and a PC terminal; The inner wall of the hollow ring is provided with a mesh porous structure, and the outer wall is provided with a plurality of symmetrical small holes; The air compression station is connected to the gas heating unit and the gas control unit in sequence through the main air pipeline. The gas control unit is connected to multiple symmetrical small holes through multiple branch air pipelines. The gas control unit is electrically connected to the PC end. The top end of the steel outer cylinder is connected to the spinneret through a hollow ring; A high temperature resistant heat insulating block is provided at the top of the steel inner cylinder; the steel inner cylinder is fixedly connected to the center of the spinneret through the high temperature resistant heat insulating block; The hollow ring is at the same height as the high temperature resistant insulation block, the steel outer cylinder is at the same height as the steel inner cylinder, and the cross-sectional area of ​​the area between the inner and outer walls of the steel outer cylinder and the area between the inner and outer walls of the steel inner cylinder are the same; The electromagnetic induction coil is sheathed on the outer surface of the steel outer cylinder through a heat insulation layer, the external power supply is electrically connected to the electromagnetic induction coil through an electronic oscillator, and the PC end is electrically connected to the electronic oscillator through a controller; The spinneret holes on the spinneret plate are located between the steel outer cylinder and the steel inner cylinder; The temperature of the gas controlled by the gas control unit is 280-310°C, and the flow rate is 1.0-4.0g / s; the temperature of the steel outer cylinder is 280-310°C, and the temperature of the steel inner cylinder is 280-310°C.

2. The method for preparing high-quality polyester industrial silk fiber according to claim 1, characterized in that: The outer diameter of the hollow ring is 280-290mm, and the inner diameter is 245-260mm; the outer diameter of the steel outer cylinder is 250-265mm, and the inner diameter is 245-260mm; the outer diameter of the steel inner cylinder is 80-122mm, and the inner diameter is 62-110mm; the height of the electromagnetic induction coil is 280-320mm, the height of the steel outer cylinder is 280-320mm, the height of the steel inner cylinder is 280-320mm, and the height of the hollow ring is 10-15mm.

3. The method for preparing high-quality polyester industrial silk fiber according to claim 1, characterized in that: The slow cooler also includes a heat-insulating shell, which wraps the outer surface of the hollow ring and the steel outer cylinder; the electromagnetic induction coil is located between the steel outer cylinder and the heat-insulating shell.

4. The method for preparing high-quality polyester industrial silk fiber according to claim 1, characterized in that: The mesh porous structure of the hollow circular ring is composed of 6 to 8 rows of circular holes, and the adjacent rows of circular holes are staggered; the aperture of the circular holes in the mesh porous structure is 1 to 2 mm, the spacing between the horizontal lines where the centers of the two adjacent rows of circular holes are located is 1.5 to 2 mm, and in each row of circular holes, the spacing between the vertical lines where the centers of the two adjacent circular holes are located is 4 to 6 mm.

5. The method for preparing high-quality polyester industrial silk fiber according to claim 1, characterized in that: The longitudinal section of the hollow circular ring along the radial direction is two identical inverted right-angled trapezoids, and the included angle between the long base and the hypotenuse of the inverted right-angled trapezoid is 40° to 60°.

6. The method for preparing high-quality polyester industrial silk fiber according to claim 1, characterized in that: A filter screen is arranged at the entrance of the small hole.

7. The method for preparing high-quality polyester industrial yarn according to any one of claims 1 to 6, characterized in that: The melt is a polyester melt, and the characteristic viscosity of the polyester melt is 1.10-1.15 dL / g; the diameter of the spinneret is 240-260 mm, the spinneret holes are arranged in 6-8 concentric circles, the diameter of the circle where the center of the innermost spinneret hole is located is 130-135 mm, and the spinneret hole diameter is 0.5-0.8 mm.

8. The method for preparing high-quality polyester industrial silk fiber according to claim 7, characterized in that: The process parameters are: cooling wind speed is 0.5-0.6 m / min, cooling wind temperature is 20-30°C, stretching ratio is 5-6, and network pressure is 0.30-0.40 MPa.

9. The method for preparing high-quality polyester industrial silk fiber according to claim 8, characterized in that: High-quality polyester industrial yarn fibers are evenly dyed, with a dyeing grade of 4.0 to 4.5, a linear density of 3350 to 3450 dtex, a linear density CV value ≤1.20%, a single yarn strength ≥0.7N, a single yarn strength CV value ≤0.80%, a single yarn diameter of 1.0 to 1.2mm, and a single yarn diameter CV value ≤0.50%.

10. According to the method for preparing high-quality polyester industrial silk fibers as claimed in claim 1, the high temperature resistant heat insulating block is made of a heat resistant silicone resin.

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