Method for automatic adjustment of the cooling of a strand

Abstract

The present application belongs to the field of chemical fiber spinning, and relates to a method for automatically adjusting yarn cooling and forming, which comprises the step of stopping spinning for changing varieties. When stopping spinning for changing varieties, the following steps are further performed: calculating the theoretical oil height of the changed variety, and measuring the actual oil height; comparing the actual oil height with (theoretical oil height ± height deviation value); if the actual oil height is less than (theoretical oil height - height deviation value), the oil height is increased; if the actual oil height is greater than (theoretical oil height + height deviation value), the oil height is decreased; if (theoretical oil height - height deviation value) is less than or equal to the actual oil height and the actual oil height is less than or equal to (theoretical oil height + height deviation value), the oil height remains unchanged; the theoretical oil height = empirical constant * solidification distance; the value range of the empirical constant is 1.5-2.5. The present application can automatically adjust the oil height when the spinning variety is changed, and can ensure excellent yarn cooling and forming effect.

Description

Technical Field

[0001] This invention belongs to the field of chemical fiber spinning and relates to a method for automatic adjustment of filament cooling and forming. Background Technology

[0002] In melt spinning, after the melt is extruded from the spinneret, the melt stream is subjected to the combined effects of winding force (winding tension, gravity, air resistance, inertial force, and surface tension, etc.) and cooling air, becoming thinner, longer, and solidifying into filaments. These filaments then undergo bundling and oiling, followed by stretching and shaping processes. Currently, bundling and oiling uses oil nozzles, which are the bundling points of the filaments. Since the oil nozzles are fixed to the oiling frame, the oiling frame must be positioned below the solidification point of the filaments. The position of the oiling frame significantly affects the temperature at the top of the frame and the cooling and shaping of the filaments. Furthermore, when changing the type of filament, each type has different thicknesses, monofilament linear densities (e.g., 83 dtex / 72f, 111 dtex / 36f), and monofilament specific surface areas, resulting in different rates of heat exchange with the external environment and varying filament cooling rates. Therefore, the required position of the oiling frame and the speed of the cooling air also differ. Thus, researching how to adjust the position of the oiling frame and the speed of the cooling air is crucial for achieving good filament cooling and shaping.

[0003] Utility model patent CN222043429U discloses an automatic height-adjustable spinning oiler for high-elasticity nylon 6, comprising two fixed frames and an upper oil nozzle support, a lower oil nozzle support, and a guide hook support disposed between the two fixed frames. Each fixed frame includes a vertical frame, two slide rails, and three crossbars. The two slide rails are arranged side by side on the vertical frame and are marked with scales. The two ends of the three crossbars are respectively slidably disposed between the two slide rails via sliders. Each slider is equipped with a scale recognition sensor. A scissor lifting device is provided between each pair of adjacent crossbars. The upper oil nozzle support, lower oil nozzle support, and guide hook support are arranged sequentially from top to bottom between the two fixed frames, and their ends are respectively fixed to the crossbars. The scale recognition sensor and the scissor lifting device are both connected to a controller. The working principle of this utility model is as follows: the operator inputs the height between the upper oil nozzle bracket, the lower oil nozzle bracket, and the guide hook bracket into the controller according to the type of yarn. The height of the crossbar is identified by the scale recognition sensor, and then the data is transmitted to the controller. The controller determines the height of the crossbar based on the data and controls the extension and retraction of the cylinder. When the cylinder extends, the hinged fork arm extends, and the crossbar rises and is fixed by the fork arm. When the cylinder retracts, the crossbar descends, thereby controlling the raising and lowering of the upper oil nozzle bracket, the lower oil nozzle bracket, and the guide hook bracket, and realizing automatic adjustment of the height of the spinning oil rack.

[0004] However, when the technical solution of this utility model patent is applied to product variety changes, the height of the working oil rack for the changed product variety needs to be known in advance. Then, the known working oil rack height is manually input, and the height of the crossbar is identified by the scale recognition sensor. The oil rack height is then adjusted to the working oil rack height. If the working oil rack height for the changed product variety is unknown, it will affect the cooling and forming effect of the yarn. Moreover, it cannot identify and adjust the wind speed of the cooling air. Even if the oil rack height is adjusted to the maximum extent, it cannot compensate for the influence of the change in the cooling wind speed, which will also affect the cooling and forming effect of the yarn.

[0005] Therefore, in order to achieve excellent filament cooling and forming effects, it is necessary to study a new method for automatic adjustment of filament cooling and forming. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a method for automatic adjustment of filament cooling and forming.

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

[0008] A method for automatic adjustment of filament cooling and forming includes a step of stopping spinning to change the type (the change of type can be a change of filament thickness and / or monofilament linear density of the same type of polymer, or a change of spinning of different types of polymers, such as a change from polyester spinning to polyamide spinning) and the spinning process after the change of type.

[0009] When changing product varieties after ceasing spinning, the following steps should also be performed:

[0010] Calculate the theoretical oil rack height for the modified product and measure the actual oil rack height (both theoretical and actual oil rack heights refer to the distance from the top of the oil rack to the top plate).

[0011] Calculate the theoretical oil rack height for the modified variety and measure the actual oil rack height;

[0012] Compare the actual oil rack height with the (theoretical oil rack height ± height deviation value);

[0013] If the actual oil rack height is less than (theoretical oil rack height - height deviation), increase the oil rack height until (theoretical oil rack height - height deviation) ≤ actual oil rack height ≤ (theoretical oil rack height + height deviation).

[0014] If the actual oil rack height is greater than (theoretical oil rack height + height deviation), reduce the oil rack height until (theoretical oil rack height - height deviation) ≤ actual oil rack height ≤ (theoretical oil rack height + height deviation).

[0015] If (theoretical oil rack height - height deviation) ≤ actual oil rack height ≤ (theoretical oil rack height + height deviation), the oil rack height remains unchanged;

[0016] The formula for calculating the theoretical oil rack height is as follows:

[0017] Theoretical oil curing rack height = empirical constant × curing distance; the empirical constant ranges from 1.5 to 2.5.

[0018] Curing distance × × ×1000, the unit of curing distance is mm; curing distance refers to the distance from the curing point of the filament to the spinneret;

[0019] Wherein, d0 is the spinneret diameter in meters (m); t1 is the temperature of the melt exiting the spinneret in ℃; t2 is the glass transition temperature of the filament (usually, the filament solidifies below the glass transition temperature), in ℃; t is the temperature of the cooling air in ℃; G is the output rate of a single spinneret in kg / h; C is the specific heat capacity of the melt (a fixed value is taken when spinning with the same polymer, for example, C is a fixed value of 2.2 when spinning PET polyester), in kJ / (kg·℃); and h is the heat transfer coefficient, a fixed value of 135 kJ / (m²). 2 (·h·℃); e is the base of the natural logarithm, taken as a fixed value of 2.718; d0, t1, t2, t, and G are all obtained manually or automatically and input into the SMU setting device according to the actual equipment and process;

[0020] The spinning process after the product change is as follows:

[0021] During the spinning process, a preset temperature is set for the top of the oiling rack, and the actual temperature of the top of the oiling rack is monitored in real time. The actual temperature of the top of the oiling rack is compared with (the preset temperature of the top of the oiling rack ± the temperature deviation value). The preset temperature is 25-30℃, and the temperature deviation value is 1-2℃.

[0022] If the actual temperature at the top of the oil rack is less than (the preset temperature at the top of the oil rack - temperature deviation), the height of the oil rack will be reduced, and the opening of the cooling air valve will be reduced. Reducing the opening of the cooling air valve will reduce the airflow speed of the cooling air until (the preset temperature at the top of the oil rack - temperature deviation) ≤ the actual temperature at the top of the oil rack ≤ (the preset temperature at the top of the oil rack + temperature deviation). The opening of the cooling air valve is set to a minimum value. When the opening of the cooling air valve reaches the minimum value, if the actual oil rack height is greater than (theoretical oil rack height + height deviation) or the actual oil rack height is less than (theoretical oil rack height - height deviation), an alarm will be triggered indicating that the cooling air supply system is abnormal, such as abnormal filter cleanliness or abnormal filter uniformity. The system will be stopped and the cooling air supply system will be checked.

[0023] If the actual temperature at the top of the oil rack is greater than (the preset temperature at the top of the oil rack + temperature deviation), the height of the oil rack will be increased, and the opening of the cooling air valve will be increased. Increasing the opening of the cooling air valve will increase the airflow speed of the cooling air until (the preset temperature at the top of the oil rack - temperature deviation) ≤ the actual temperature at the top of the oil rack ≤ (the preset temperature at the top of the oil rack + temperature deviation). The cooling air valve opening has a maximum value. When the cooling air valve opening reaches the maximum value, if the actual oil rack height is greater than (theoretical oil rack height + height deviation) or the actual oil rack height is less than (theoretical oil rack height - height deviation), an alarm will be triggered indicating that the cooling air supply system is abnormal, such as abnormal filter cleanliness or abnormal filter uniformity. The system will be stopped and the cooling air supply system will be checked.

[0024] If (preset temperature at the top of the oil rack - temperature deviation) ≤ actual temperature at the top of the oil rack ≤ (preset temperature at the top of the oil rack + temperature deviation), then the height of the oil rack and the opening of the cooling air valve remain unchanged, and normal spinning continues.

[0025] The principle of this invention is as follows: When a monofilament is first extruded from the spinneret, it is still at a high temperature. The further away from the spinneret, the lower the temperature of the monofilament. Under the action of a certain cooling air, the distance between the oil rack and the spinneret is fully utilized for cooling, which can save cooling air resources and reduce cooling costs. When using an oil nozzle to bundle and apply oil below the solidification point of the filament, since the oil nozzle is installed on the oil rack, the temperature of the top of the oil rack should be within a suitable range to ensure the cooling and forming effect of the filament, such as the CV value of the yarn unevenness meeting the requirements. This invention quantitatively calculates the theoretical oil rack height of the changed variety by pre-inputting the corresponding parameters, and automatically adjusts the oil rack height to keep the temperature of the top of the oil rack within a suitable range, thereby achieving excellent filament cooling and forming effect.

[0026] During the spinning process after the spinning process begins, the height of the oiler and the opening of the cooling air valve are automatically adjusted. This not only makes full use of the distance between the oiler and the spinneret for cooling, reducing cooling costs, but also enhances the cooling effect and improves cooling efficiency through the cooling air. Furthermore, it keeps the temperature at the top of the oiler within a suitable range to ensure the cooling and forming effect of the filament.

[0027] As a preferred technical solution:

[0028] As described above, the method for automatic adjustment of filament cooling and forming involves calculating the theoretical oil rack height of the changed product using an SMU (Setting Monitoring Unit, a monitoring and setting system commonly used in polyester and other filament production equipment), measuring the actual oil rack height using a rangefinder, and comparing the actual oil rack height with (theoretical oil rack height ± height deviation) using the SMU.

[0029] The height deviation value of the automatic adjustment method for filament cooling and forming as described above is 50-100mm.

[0030] As described above, the automatic adjustment method for filament cooling and forming involves testing the evenness CV value of the cooled filament by varying the empirical constant within the range of 1.5-2.5 and the preset temperature within the range of 25-30℃. When the evenness CV value reaches its minimum, the corresponding empirical constant value is the optimal empirical constant value, and the corresponding preset temperature is the optimal preset temperature.

[0031] As described above, in the automatic adjustment method for filament cooling and forming, the opening degree of the cooling air valve is ≤100% (0% < 100%). The cooling air valve can be fully open but not fully closed. If the air speed is still insufficient when the cooling air valve is fully open, it indicates that the filter of the air supply system is clogged and the machine needs to be stopped for repair.

[0032] As described above, the automatic adjustment method for filament cooling and forming involves setting a preset temperature for the top of the oil rack via an SMU (Steam Unit) setter. The actual temperature of the top of the oil rack is obtained via a temperature sensor. If there are multiple temperature sensors, the average of the measured temperature values ​​is taken as the actual temperature of the top of the oil rack. The temperature sensor is installed on the top of the oil rack. The comparison between the actual temperature of the top of the oil rack and (the preset temperature of the top of the oil rack ± the temperature deviation value) is completed via the SMU setter.

[0033] In the above-described method for automatic adjustment of filament cooling and forming, the increase and decrease of the opening of the cooling air valve are accomplished by an SMU setter and a second execution controller, which is connected to both the SMU setter and the cooling air valve.

[0034] As described in any of the preceding methods, the method for automatically adjusting the cooling and forming of filaments involves increasing or decreasing the height of the oil rack via an SMU setter, a first execution controller, a cylinder, an oil rack slide rod, and a sliding sleeve. The sliding sleeve is fixed to the side of the oil rack, the oil rack slide rod is vertically fixed, and the sliding sleeve is fitted onto the oil rack slide rod in a sliding manner. The working end of the piston rod of the cylinder is fixedly connected to the bottom of the oil rack. The first execution controller is connected to both the SMU setter and the cylinder. The SMU setter controls the working end of the piston rod of the cylinder and the oil rack to move upward or downward via the first execution controller, thereby decreasing or increasing the height of the oil rack, respectively.

[0035] Beneficial effects:

[0036] (1) When the spinning variety is changed, even if the working oil rack height of the changed variety is unknown, the method provided by the present invention can quantitatively calculate the theoretical oil rack height of the changed variety by inputting the corresponding parameters, and realize automatic adjustment of the oil rack height and automatic monitoring of the filament cooling operation within the set range, so as to ensure that the filament unevenness CV value after cooling and forming reaches an excellent level.

[0037] (2) During the spinning process, the method provided by the present invention monitors the cooling of the yarn, realizes automatic adjustment of the height of the oil rack and the opening of the cooling air valve, ensures excellent cooling and forming effect, and provides alarm reminders when the adjustment range is exceeded, so as to promptly check and repair. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural schematic diagram of the automatic adjustment device for filament cooling and forming in Example 1;

[0039] Figure 2 This is a schematic diagram of the automatic adjustment device for filament cooling and forming in Example 1. The green arrow represents the airflow direction of the cooling air, the blue arrow represents the direction of the filament, and the red arrow represents the airflow direction of the compressed air.

[0040] Figure 3 This is a partial structural schematic diagram of the automatic adjustment device for filament cooling and forming in Example 1. The red arrows represent the airflow direction of compressed air.

[0041] In the diagram, 1-right side plate, 2-filter screen, 3-top plate, 4-left side plate, 5-oil rack slide bar, 6-pressure stabilizing chamber, 7-air valve, 8-oil rack, 9-oil nozzle, 10-SMU setting device, 11-rangefinder, 12-temperature display screen, 13-deviation display screen, 14-temperature sensor, 15-sliding sleeve, 16-cylinder, 17-first actuator controller, 18-second actuator controller, 19-alarm, 20-filament, 21-spinning assembly, 22-guide hook, 23-fixing rod, 24-oil nozzle slide bar, 25-guide hook slide bar, 26-base plate. Detailed Implementation

[0042] 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.

[0043] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0044] (1) Evenness CV value: Tested according to GB / T 14346-2015 "Test method for evenness of chemical fiber filaments - capacitance method".

[0045] (2) Average difference coefficient U value of yarn unevenness: The test was conducted in accordance with GB / T 14346-2015 "Test method for yarn unevenness of chemical fiber filaments - capacitance method".

[0046] (3) Half-inhibition value: Tested according to GB / T 14346-2015 "Test method for unevenness of chemical fiber filament yarn - capacitance method".

[0047] (4) Dyeing uniformity: Tested according to GB / T6508-2015 "Test method for dyeing uniformity of polyester filament".

[0048] Example 1

[0049] An automatic adjustment device for filament cooling and forming, such as Figure 1 , Figure 2 and Figure 3 As shown, it consists of a side-blowing air box, filter screen 2, oil rack slide bar 5, pressure stabilizing chamber 6, air valve 7, oil rack 8, oil nozzle 9, SMU setting device 10, rangefinder 11, temperature display screen 12, deviation display screen 13, temperature sensor 14, sliding sleeve 15, cylinder 16, first actuator controller 17, second actuator controller 18, alarm 19, guide wire hook 22, fixing rod 23, oil nozzle slide bar 24, and guide wire hook slide bar 25;

[0050] The side-blowing air box is a cuboid structure formed by connecting the right side plate 1, the top plate 3, the left side plate 4 and the bottom plate 26 in sequence. The pressure stabilizing chamber 6 is fixed to the rear side of the side-blowing air box. The filter screen 2 is fixed between the pressure stabilizing chamber 6 and the side-blowing air box. The filter screen 2 is a honeycomb rectifier plate. The interior of the pressure stabilizing chamber 6 is connected to the interior of the side-blowing air box through the filter screen 2. The air valve 7 is set at the bottom of the pressure stabilizing chamber 6. The air valve 7 controls the air volume of cooling air entering the pressure stabilizing chamber 6.

[0051] The oil rack 8 is a cuboid structure composed of a right wall panel, a top wall panel, a left wall panel, and a rear wall panel connected in sequence. The interior of the oil rack 8 is a cavity. The oil nozzle slide rod 24 and the guide hook slide rod 25 are both horizontally positioned within the cavity of the oil rack 8, parallel to the left-right direction. The oil nozzle slide rod 24 is located above the guide hook slide rod 25, and the two are spaced apart. The left ends of both the oil nozzle slide rod 24 and the guide hook slide rod 25 are fixedly connected to the left wall panel of the oil rack 8, and the right ends of both are fixedly connected to the right wall panel of the oil rack 8. The fixing rod 23 is vertically positioned and is connected to the oil nozzle slide rod... 24 and guide hook slide 25 are fixedly connected. Oil nozzle 9 is fixed on oil nozzle slide 24, and guide hook 22 is fixed on guide hook slide 25. Oil nozzle 9 is located above guide hook 22. The function of fixing rod 23 is to prevent deformation and vibration of oil nozzle slide 24 and guide hook slide 25, and to avoid changes in the positional relationship between oil nozzle 9 and guide hook 22. The number of fixing rods 23 is determined according to the actual fixing effect. The number of oil nozzles 9 and guide hooks 22 is determined according to the number of filaments in the spinning position. The top wall plate of oil rack 8 is provided with a first strip hole, which is located directly above oil nozzle 9.

[0052] The oil rack 8 is horizontally positioned inside the side-blowing box; the sliding sleeve 15 consists of a left sliding sleeve and a right sliding sleeve, with the left sliding sleeve fixed to the front end of the left wall plate of the oil rack 8 and the right sliding sleeve fixed to the front end of the right wall plate of the oil rack 8, thus achieving a fixed connection between the sliding sleeve 15 and the oil rack 8; the oil rack slide rod 5 consists of a left oil rack slide rod and a right oil rack slide rod, which are vertically fixed to the left and right sides inside the side-blowing box, respectively. The left sliding sleeve is fitted onto the left oil rack slide rod and slidably connected to it, while the right sliding sleeve is fitted onto the left oil rack slide rod. The piston rod of cylinder 16 is vertically arranged on and slidably connected to the right oil rack slide rod, with the working end of the piston rod located at the top of the piston rod and fixedly connected to the bottom of the rear wall plate of oil rack 8; temperature sensor 14 is installed on the top of oil rack 8 to measure the actual temperature of the top of oil rack 8; a second strip hole is provided on the top plate 3 of the side blowing box, which is located directly above the first strip hole, and the wire passes through the second strip hole and the first strip hole in sequence to enter the oil nozzle 9;

[0053] The rangefinder 11, temperature display screen 12, deviation display screen 13, and alarm 19 are all fixed on the left side of the oil rack 8. The rangefinder 11 measures the actual height of the oil rack, the temperature display screen 12 displays the actual temperature at the top of the oil rack, and the deviation display screen 13 displays both the height deviation value and the temperature deviation value. When the measured actual temperature at the top of the oil rack exceeds (the preset temperature at the top of the oil rack ± the temperature deviation value) or when the measured actual height of the oil rack exceeds (the theoretical height of the oil rack ± the height deviation value), the deviation display screen 13 changes from green to red, and the alarm 19 sounds an alarm.

[0054] The rangefinder 11, temperature display screen 12, deviation display screen 13, temperature sensor 14, and alarm 19 are all connected to the SMU setting device 10; the preset temperature at the top of the oil rack is set through the SMU setting device 10, and the theoretical height of the oil rack is set through the SMU setting device 10.

[0055] The first execution controller 17 is connected to the SMU setter 10 and the cylinder 16. The SMU setter 10 controls the compressed air to enter and exit the cylinder 16 and the working end of the piston rod of the cylinder 16 to rise and fall through the first execution controller 17, thereby driving the oil rack 8 to move up or down through the sliding sleeve 15 and the oil rack slide rod 5, respectively reducing or increasing the actual oil rack height.

[0056] The second execution controller 18 is connected to both the SMU setter 10 and the air valve 7. The SMU setter 10 controls the opening of the air valve 7 to increase or decrease through the second execution controller 18. The cooling air enters the pressure stabilizing chamber 6 through the air valve 7, is filtered by the filter screen 2, and is then evenly delivered to the yarn to cool it.

[0057] like Figure 2 As shown, the cooling air enters the side blowing box after passing through the air valve 7, the pressure stabilizing chamber 6 and the filter screen 2. The filament 20 coming out of the spinning assembly 21 moves downward. After being cooled, the filament 20 passes through the oil nozzle 9 and the guide hook 22 from top to bottom, and then enters the winding process.

[0058] Example 2

[0059] A method for automatic adjustment of filament cooling and forming, using an automatic adjustment device for filament cooling and forming provided in Example 1, comprises the following steps:

[0060] (1) Set parameters;

[0061] Before the product change, the specifications of the yarn were 83dtex / 72f, the actual oil rack height was 800mm, and the cooling air velocity was 0.26m / s;

[0062] After the product change, a melt spinning process was adopted to produce round bright FDY polyester filaments with specifications of 83 dtex / 36f (fineness 83 dtex, spinneret orifice number 36). In the spinning process, the spinneret orifice diameter d0 was 0.00022 m, the melt exit temperature t1 was 290℃, the filament was cooled using a side-blown air box with a cooling air temperature t of 22℃, the glass transition temperature t2 was 69℃, the winding speed was 5000 m / min, the single spinneret output G was 0.069167 kg / h, the melt specific heat capacity C was 2.2 kJ / (kg·℃), and the heat transfer coefficient h was 135 kJ / (m³). 2 (·h·℃), e is 2.718;

[0063] The empirical constant is 2, the height deviation is 100mm, the preset temperature of the top of the oil rack is 29℃, and the temperature deviation is 2℃.

[0064] (2) When spinning is stopped due to variety change, the theoretical oil rack height is automatically calculated and the oil rack height is automatically adjusted;

[0065] When spinning is suspended due to product change, after inputting the above process parameters into the SMU setter, calculate the theoretical oil rack height according to the following formula:

[0066] Theoretical oil rack height = empirical constant × curing distance;

[0067] Curing distance × × ×1000, the curing distance is in mm;

[0068] The theoretical oil rack height = 2 × × × ×1000=1072mm;

[0069] The automatic adjustment process for the oil pan height is as follows: The SMU setting unit compares the actual oil pan height measured by the rangefinder with (1072mm±100mm); if the actual oil pan height < (1072mm-100mm), the oil pan height is increased until (1072mm-100mm) ≤ actual oil pan height ≤ (1072mm+100mm); if the actual oil pan height > (1072mm+100mm), the oil pan height is decreased until (1072mm-100mm) ≤ actual oil pan height ≤ (1072mm+100mm); if (1072mm-100mm) ≤ actual oil pan height ≤ (1072mm+100mm), the oil pan height remains unchanged.

[0070] Increasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to descend, causing the sliding sleeve to move downward along the oil rack slide rod. Decreasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to rise, causing the sliding sleeve to move upward along the oil rack slide rod.

[0071] When the actual oil rack height is less than (1072mm-100mm) or greater than (1072mm+100mm), the deviation display screen shows red and the alarm sounds. When (1072mm-100mm) ≤ actual oil rack height ≤ (1072mm+100mm), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0072] (3) During the spinning process after the spinning begins, the height of the oil rack and the opening of the cooling air valve are automatically adjusted. The specific process is as follows:

[0073] The SMU setter compares the actual temperature at the top of the oil rack measured by the temperature sensor with the value of (29℃±2℃);

[0074] If the actual temperature at the top of the oil rack is less than (29℃-2℃), reduce the height of the oil rack and simultaneously reduce the opening of the cooling air valve until (29℃-2℃) ≤ the actual temperature at the top of the oil rack ≤ (29℃+2℃). The opening of the cooling air valve is set to a minimum value (0%). When the opening of the cooling air valve reaches the minimum value, if the actual oil rack height is greater than (1072mm+100mm) or the actual oil rack height is less than (1072mm-100mm), stop the machine and check the cooling air supply system.

[0075] If the actual temperature at the top of the oil rack is greater than (29℃ + 2℃), increase the height of the oil rack and simultaneously increase the opening of the cooling air valve until (29℃ - 2℃) ≤ the actual temperature at the top of the oil rack ≤ (29℃ + 2℃). The opening of the cooling air valve is set to a maximum value (100%). When the opening of the cooling air valve reaches the maximum value, if the actual oil rack height is greater than (1072mm + 100mm) or the actual oil rack height is less than (1072mm - 100mm), stop the machine and check the cooling air supply system.

[0076] If (29℃-2℃)≤actual temperature at the top of the oil rack≤(29℃+2℃), then the height of the oil rack and the opening of the cooling air valve remain unchanged, and normal spinning continues.

[0077] Increasing the opening of the cooling air valve is achieved by increasing the opening of the air valve through the second actuator controller, and decreasing the opening of the cooling air valve is achieved by decreasing the opening of the air valve through the second actuator controller.

[0078] When the actual temperature at the top of the oil rack is less than (29℃-2℃) or greater than (29℃+2℃), the deviation display screen turns red and the alarm sounds. When (29℃-2℃) ≤ the actual temperature at the top of the oil rack ≤ (29℃+2℃), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0079] In this embodiment, during the spinning process, the actual height of the oil rack measured by the rangefinder is 972mm. The actual temperature of the top of the oil rack is monitored in real time by the temperature sensor and displayed on the temperature display screen. The SMU setting device compares the actual temperature of the top of the oil rack with (the preset temperature of the top of the oil rack ± the temperature deviation value). The measured actual temperature of the top of the oil rack is 31.5℃, which exceeds the set range by 29±2℃. The deviation display screen turns red, the alarm sounds, and the data is fed back to the SMU setting device. The SMU setting device automatically identifies that the cooling air speed is too low and the oil rack height is too low. At this time, the first execution controller lowers the working end of the piston rod, causing the oil rack to move downward along the oil rack slide rod. At the same time, it controls the second execution controller to increase the opening of the air valve. When the measured actual temperature of the top of the oil rack is less than 31℃, the actual height of the oil rack measured by the rangefinder is 1000mm. Both the actual oil rack height and the actual temperature of the top of the oil rack are within the set range. The color of the deviation display screen returns to the original normal color, the alarm is cleared, and the automatic adjustment of the spinning cooling system is completed.

[0080] The yarn obtained in Example 2 had an unevenness CV value of 0.91%, an average unevenness coefficient U value of 0.72%, and a half-inhibition value of 0.57% (the test conditions for the unevenness CV value, average unevenness coefficient U value, and half-inhibition value were: test speed 400 m / min, test time 1 min, measuring groove width 0.36 mm, twister: S-twist, twisting speed 22000 r / min, nominal count 83 dtex / 36f. The nominal count is the product specification. The same test conditions are used for the same product specification. Since the fineness of different product specifications varies greatly, different twisting speeds are required, which complies with the provisions of GB / T 14346-2015). The dyeing uniformity was grade 4.5.

[0081] Comparative Example 1

[0082] A method for automatically adjusting the cooling and forming of filaments, which differs from Embodiment 2 only in that the oil frame adopts the automatically adjustable height spinning oil frame provided by the utility model with patent announcement number CN222043429U (spinning parameters remain unchanged).

[0083] The final yarn had an unevenness CV value of 1.53%, an average unevenness coefficient U value of 1.21%, and a half-inhibition value of 0.86% (the test conditions for unevenness CV, average unevenness coefficient U, and half-inhibition value were: test speed of 400 m / min, test time of 1 min, measurement groove width of 0.36 mm, twister: S twist, twisting speed of 22000 r / min, nominal count of 83 dtex / 36f), and a dyeing uniformity of 4.0 grade.

[0084] Compared to Example 2, the yarn unevenness coefficient (CV) of the yarn obtained in Comparative Example 1 increased by 68.1%, the average unevenness difference coefficient (U) increased by 68.1%, and the half-suppression value increased by 50.9%. This is because the yarn specifications before the variety change were 83 dtex / 72f, the actual spinneret height was 800 mm, the cooling air velocity was 0.26 m / s, the actual spinneret height was small, the spinneret was close to the spinneret, the cooling air velocity was low, and the dpf (denier per 100 mm) was small. The abbreviation for filament (referring to the fineness of a single fiber in yarn) indicates that after the yarn variety was changed to 83dtex / 36f, the dpf (dextral density) increased significantly, and the required cooling air velocity also increased significantly. Comparative Example 1 uses the automatic height adjustment spinning oil rack provided by the utility model with patent announcement number CN222043429U. The actual height of the oil rack was adjusted from 800mm to 1072mm, and the cooling air velocity remained at 0.26m / s. At this time, the actual temperature at the top of the oil rack was 33℃, which exceeded the set range by 29±2℃. The actual temperature at the top of the oil rack was too high, and the cooling air velocity was too low to meet the cooling requirements of the yarn. When the cooling air velocity is too low, on the one hand, the interference of outdoor airflow on the yarn increases, and on the other hand, the solidification speed of the yarn slows down, which increases the factors of yarn drifting and vibration, thereby affecting the yarn evenness. After forming, the linear density in the length direction is uneven, and the final measured yarn unevenness rate is too high, and the dyeing is slightly uneven.

[0085] Comparative Example 2

[0086] A method for automatic adjustment of filament cooling and forming is different from Example 2 only in that the empirical constant is 1.

[0087] The final yarn had a yarn unevenness CV value of 2.05%, an average yarn unevenness coefficient U value of 1.63%, and a half-inhibition value of 1.05% (the test conditions for yarn unevenness CV, average yarn unevenness coefficient U, and half-inhibition value were: test speed of 400 m / min, test time of 1 min, measurement groove width of 0.36 mm, twister: S twist, twisting speed of 22000 r / min, nominal count of 83 dtex / 36f), and dyeing uniformity of grade 3.0.

[0088] Compared to Example 2, the yarn unevenness coefficient (CV) of the yarn obtained in Comparative Example 2 increased by 125.3%, the average unevenness difference coefficient (U) increased by 126.4%, and the half-suppression value increased by 84.2%. This is because the yarn specification before the variety change was 83 dtex / 72f, the actual spinneret height was 800 mm, and the cooling air velocity was 0.26 m / s. The actual spinneret height was small, the spinneret was close to the spinneret, the cooling air velocity was low, and the dpf was small. After the variety was changed to 83 dtex / 36f, the dpf increased significantly, and the requirement for cooling air velocity also increased significantly. The empirical constant for Comparative Example 2 was 1, and the calculated theoretical spinneret height was 536 mm. The set range for the spinneret height was 436-636 mm, which was smaller than the actual spinneret height of 800 mm before the variety change. When the actual spinneret height was adjusted to the range of 436-636 mm, the actual temperature at the top of the spinneret was >40°C. If the temperature exceeds the set range of 29±2℃, the opening of the cooling air valve needs to be continuously increased until it reaches the maximum value of 100%. At this point, the air velocity of the cooling air is 0.9m / s, and the filament is in a state of rapid cooling, resulting in inconsistent internal and external structures and forming a skin-core structure. When the air velocity of the cooling air is too high, the turbulence factor increases, and any turbulence in the airflow will inevitably cause the filament to vibrate or drift. When the vibration amplitude reaches a certain value, it will be transmitted to the solidification zone, causing severe unevenness in the linear density of the filament along its length. The measured unevenness rate is significantly higher, and the dyeing shows severe streaks and uneven dyeing, making it a defective product. This indicates that when the empirical constant is 1, if the empirical constant is too small, it will lead to an increase in the unevenness rate, which has an adverse effect on product quality.

[0089] Example 3

[0090] A method for automatic adjustment of filament cooling and forming, using an automatic adjustment device for filament cooling and forming provided in Example 1, comprises the following steps:

[0091] (1) Set parameters;

[0092] Before the product change, the specifications of the yarn were 83dtex / 36f, the actual oil rack height was 1050mm, and the cooling air velocity was 0.4m / s.

[0093] After the product change, a melt spinning process was adopted to produce round bright FDY polyester filaments with specifications of 111 dtex / 36f (fineness 111 dtex, spinneret orifice number 36). In the spinning process, the spinneret orifice diameter d0 was 0.00022 m, the melt exit temperature t1 was 290℃, the filament was cooled using a side-blown air box with a cooling air temperature t of 22℃ and a cooling air velocity of 0.45 m / s, the glass transition temperature t2 was 69℃, the winding speed was 5000 m / min, the single spinneret output G was 0.0925 kg / h, the melt specific heat capacity C was 2.2 kJ / (kg·℃), and the heat transfer coefficient h was 135 kJ / (m³). 2 (·h·℃), e is 2.718;

[0094] The empirical constant is 1.5, the height deviation is 100mm, the preset temperature of the top of the oil rack is 30℃, and the temperature deviation is 2℃.

[0095] (2) When changing the shutdown time, automatically calculate the theoretical oil rack height and automatically adjust the oil rack height;

[0096] When changing the shutdown procedure, after entering the above process parameters into the SMU setter, calculate the theoretical oil rack height according to the following formula:

[0097] Theoretical oil rack height = empirical constant × curing distance;

[0098] Curing distance × × ×1000, the curing distance is in mm;

[0099] Therefore, the theoretical oil rack height = 1.5 × × × ×1000=1075mm;

[0100] The automatic adjustment process for the oil pan height is as follows: The SMU setting unit compares the actual oil pan height measured by the rangefinder with (1075mm ± 100mm); if the actual oil pan height < (1075mm - 100mm), the oil pan height is increased until (1075mm - 100mm) ≤ actual oil pan height ≤ (1075mm + 100mm); if the actual oil pan height > (1075mm + 100mm), the oil pan height is decreased until (1075mm - 100mm) ≤ actual oil pan height ≤ (1075mm + 100mm); if (1075mm - 100mm) ≤ actual oil pan height ≤ (1075mm + 100mm), the oil pan height remains unchanged.

[0101] Increasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to descend, causing the sliding sleeve to move downward along the oil rack slide rod. Decreasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to rise, causing the sliding sleeve to move upward along the oil rack slide rod.

[0102] When the actual oil rack height is less than (1075mm-100mm) or greater than (1075mm+100mm), the deviation display screen turns red and the alarm sounds. When (1075mm-100mm) ≤ actual oil rack height ≤ (1075mm+100mm), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0103] (3) During the spinning process after the spinning begins, the height of the oil rack and the opening of the cooling air valve are automatically adjusted. The specific process is as follows:

[0104] The SMU setter compares the actual temperature at the top of the oil rack measured by the temperature sensor with the value of (30℃±2℃);

[0105] If the actual temperature at the top of the oil rack is less than (30℃-2℃), reduce the height of the oil rack and simultaneously reduce the opening of the cooling air valve until (30℃-2℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃+2℃). The opening of the cooling air valve is set to a minimum value (0%). When the opening of the cooling air valve reaches the minimum value, if the actual oil rack height is greater than (1075mm+100mm) or the actual oil rack height is less than (1075mm-100mm), stop the machine and check the cooling air supply system.

[0106] If the actual temperature at the top of the oil rack is greater than (30℃ + 2℃), increase the height of the oil rack and simultaneously increase the opening of the cooling air valve until (30℃ - 2℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃ + 2℃). The opening of the cooling air valve is set to a maximum value (100%). When the opening of the cooling air valve reaches the maximum value, if the actual oil rack height is greater than (1075mm + 100mm) or the actual oil rack height is less than (1075mm - 100mm), stop the machine and check the cooling air supply system.

[0107] If (30℃-2℃)≤actual temperature at the top of the oil rack≤(30℃+2℃), then the height of the oil rack and the opening of the cooling air valve remain unchanged, and normal spinning continues.

[0108] Increasing the opening of the cooling air valve is achieved by increasing the opening of the air valve through the second actuator controller, and decreasing the opening of the cooling air valve is achieved by decreasing the opening of the air valve through the second actuator controller.

[0109] When the actual temperature at the top of the oil rack is less than (30℃-2℃) or greater than (30℃+2℃), the deviation display screen turns red and the alarm sounds. When (30℃-2℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃+2℃), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0110] In this embodiment, during the spinning process, the actual height of the oil rack measured by the rangefinder is 1120mm, which is within the range of 975-1175mm. At this time, the temperature sensor monitors the actual temperature of the top of the oil rack in real time and displays it on the temperature display screen. The SMU setting device compares the actual temperature of the top of the oil rack with (the preset temperature of the top of the oil rack ± the temperature deviation value). The measured actual temperature of the top of the oil rack is 33℃, which exceeds the set range by 30±2℃. The deviation display screen shows red, the alarm sounds, and the data is fed back to the SMU setting device. The SMU setting device automatically recognizes that the actual temperature of the top of the oil rack exceeds the set range and judges that the cooling air speed is too low and the actual oil rack height is too low. At this time, the first execution controller lowers the working end of the piston rod of the cylinder to make the oil rack move down along the oil rack slide rod. At the same time, the second execution controller increases the opening of the cooling air valve and increases the cooling air speed.

[0111] When the actual height of the oil rack measured by the rangefinder was greater than 1175mm, the temperature display showed a real-time actual temperature of 32.6℃ at the top of the oil rack, which was still outside the set range of 30±2℃. At this time, the deviation display showed red, and the alarm continued to indicate an abnormality. Upon inspection after shutdown, it was found that the filter in the pressure stabilizing chamber was clogged. As the opening of the air valve increased, the air speed did not change, and the actual temperature at the top of the oil rack did not change. After replacing the filter, the temperature display showed a real-time actual temperature of 27℃ at the top of the oil rack, which was outside the set range of 30±2℃. At this time, the first actuator controller raised the working end of the piston rod of the cylinder, causing the oil rack to move upward along the oil rack slide rod. At the same time, the second actuator controller reduced the opening of the cooling air valve, reducing the air speed. Finally, the rangefinder measured the actual height of the oil rack to be 1100mm, and the temperature sensor monitored and the temperature display showed a real-time actual temperature of 28.9℃ at the top of the oil rack. The color of the deviation display returned to normal, and the alarm was cleared.

[0112] The yarn obtained in Example 3 had a yarn unevenness CV value of 0.92%, an average yarn unevenness coefficient U value of 0.72%, and a half-inhibition value of 0.47% (the test conditions for yarn unevenness CV value, average yarn unevenness coefficient U value, and half-inhibition value were: test speed of 400 m / min, test time of 1 min, measurement groove width of 0.36 mm, twister: S twist, twisting speed of 21000 r / min, nominal count of 111 dtex / 36f), and a dyeing uniformity of 4.5 grade.

[0113] Comparative Example 3

[0114] A method for automatic adjustment of filament cooling and forming is different from Example 3 only in that the empirical constant is 1.

[0115] The final yarn had an unevenness CV value of 2.16%, an average unevenness coefficient U value of 1.73%, and a half-inhibition value of 1.1% (the test conditions for unevenness CV, average unevenness coefficient U, and half-inhibition value were: test speed of 400 m / min, test time of 1 min, measurement groove width of 0.36 mm, twister: S twist, twisting speed of 21000 r / min, nominal count of 111 dtex / 36f), and a dyeing uniformity of 3.0 grade.

[0116] Compared to Example 3, the yarn unevenness coefficient (CV) of the yarn obtained in Comparative Example 3 increased by 134.8%, the average difference coefficient of unevenness (U) increased by 140.3%, and the half-suppression value increased by 134.0%. This is because when the yarn specification is changed from 83 dtex / 36f to 111 dtex / 36f, the dpf increases, and the airflow requirement for cooling air also increases significantly. The empirical constant for Comparative Example 3 is 1, and the calculated theoretical oil rack height is 717 mm. The set range for the oil rack height is 617-817 mm. This set range is less than the actual oil rack height of 1050 mm before the yarn change. When the actual oil rack height is adjusted to the range of 617-817 mm, the actual temperature at the top of the oil rack is >35°C, which exceeds the set range by 30±2°C, requiring sustained cooling. Continue to increase the opening of the cooling air valve to make the cooling air speed reach 0.8 m / s. At this time, the cooling air speed is too high, and the turbulence factor increases. Any turbulence in the air flow will cause the filament to vibrate or drift. When the vibration amplitude reaches a certain value, it will be transmitted to the solidification zone, causing the linear density of the filament to be severely uneven in the length direction. The measured unevenness rate is seriously high, and the dyeing is severely striped and uneven, which is a defective product. This shows that when the empirical constant is 1, the empirical constant is too small, which will lead to an increase in the unevenness rate and have an adverse effect on the product quality.

[0117] Example 4

[0118] A method for automatic adjustment of filament cooling and forming, using an automatic adjustment device for filament cooling and forming provided in Example 1, comprises the following steps:

[0119] (1) Set parameters;

[0120] Before the product change, the specifications of the yarn were 83dtex / 36f, the actual oil rack height was 1050mm, and the cooling air velocity was 0.4m / s.

[0121] After the product change, a melt spinning process was adopted to produce round bright FDY polyester filaments with specifications of 83 dtex / 72f (fineness 83 dtex, spinneret orifice number 72). In the spinning process, the spinneret orifice diameter d0 was 0.00016 m, the melt exit temperature t1 was 290℃, the filament was cooled using a side-blown air box with a cooling air temperature t of 22℃ and a cooling air velocity of 0.26 m / s, the glass transition temperature t2 of the filament was 69℃, the winding speed was 5000 m / min, the single spinneret output G was 0.0346 kg / h, the melt specific heat capacity C was 2.2 kJ / (kg·℃), and the heat transfer coefficient h was 135 kJ / (m³). 2 (·h·℃), e is 2.718;

[0122] The empirical constant is 2.5, the height deviation is 50mm, the preset temperature of the top of the oil rack is 30℃, and the temperature deviation is 1℃.

[0123] (2) When changing the shutdown time, automatically calculate the theoretical oil rack height and automatically adjust the oil rack height;

[0124] When product changes and spinning is suspended, after inputting the above process parameters into the SMU setter, calculate the theoretical oil rack height according to the following formula:

[0125] Theoretical oil rack height = empirical constant × curing distance;

[0126] Curing distance × × ×1000, the curing distance is in mm;

[0127] Therefore, the theoretical oil rack height = 2.5 × × × ×1000=921mm;

[0128] The automatic adjustment process for the oil pan height is as follows: The SMU setting unit compares the actual oil pan height measured by the rangefinder with (921mm±50mm); if the actual oil pan height < (921mm-50mm), the oil pan height is increased until (921mm-50mm) ≤ actual oil pan height ≤ (921mm+50mm); if the actual oil pan height > (921mm+50mm), the oil pan height is decreased until (921mm-50mm) ≤ actual oil pan height ≤ (921mm+50mm); if (921mm-50mm) ≤ actual oil pan height ≤ (921mm+50mm), the oil pan height remains unchanged.

[0129] Increasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to descend, causing the sliding sleeve to move downward along the oil rack slide rod. Decreasing the height of the oil rack is achieved by the first actuator controlling the working end of the piston rod of the cylinder to rise, causing the sliding sleeve to move upward along the oil rack slide rod.

[0130] When the actual oil rack height is less than (921mm-50mm) or greater than (921mm+50mm), the deviation display screen turns red and the alarm sounds. When (921mm-50mm) ≤ actual oil rack height ≤ (921mm+50mm), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0131] (3) During the spinning process after the spinning begins, the height of the oil rack and the opening of the air valve are automatically adjusted. The specific process is as follows:

[0132] The SMU setter compares the actual temperature at the top of the oil rack measured by the temperature sensor with the value of (30℃±2℃);

[0133] If the actual temperature at the top of the oil rack is less than (30℃-1℃), reduce the height of the oil rack and simultaneously reduce the opening of the cooling air valve until (30℃-1℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃+1℃). The opening of the cooling air valve is set to a minimum value (0%). When the opening of the cooling air valve reaches the minimum value, if the actual oil rack height is greater than (921mm+50mm) or the actual oil rack height is less than (921mm-50mm), stop the machine and check the cooling air supply system.

[0134] If the actual temperature at the top of the oil rack is greater than (30℃ + 1℃), increase the height of the oil rack and simultaneously increase the opening of the cooling air valve until (30℃ - 1℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃ + 1℃). The opening of the cooling air valve is set to a maximum value (100%). When the opening of the cooling air valve reaches the maximum value, if the actual oil rack height is greater than (921mm + 50mm) or the actual oil rack height is less than (921mm - 50mm), stop the machine and check the cooling air supply system.

[0135] If (30℃-1℃)≤actual temperature at the top of the oil rack≤(30℃+1℃), then the height of the oil rack and the opening of the cooling air valve remain unchanged, and normal spinning continues.

[0136] Increasing the opening of the cooling air valve is achieved by increasing the opening of the air valve through the second actuator controller, and decreasing the opening of the cooling air valve is achieved by decreasing the opening of the air valve through the second actuator controller.

[0137] When the actual temperature at the top of the oil rack is less than (30℃-1℃) or greater than (30℃+1℃), the deviation display screen turns red and the alarm sounds. When (30℃-1℃) ≤ the actual temperature at the top of the oil rack ≤ (30℃+1℃), the color of the deviation display screen returns to its original normal color and the alarm is deactivated.

[0138] In this embodiment, during the spinning process, the actual height of the oil rack measured by the rangefinder is 950mm, falling within the range of 871-971mm. At this point, the temperature sensor monitors the actual temperature of the top of the oil rack in real time and displays it on the temperature display screen. The SMU setting device compares the actual temperature of the top of the oil rack with (the preset temperature of the top of the oil rack ± temperature deviation). The measured actual temperature of the top of the oil rack is 28.5℃, exceeding the set range by 30±1℃. The deviation display screen turns red, the alarm sounds, and the data is fed back to the SMU setting device, which automatically identifies the actual temperature of the top of the oil rack. If the temperature exceeds the set range, it is determined that the cooling air speed and the actual oil rack height are too high. At this time, the first actuator controller raises the working end of the piston rod of the control cylinder, causing the oil rack to move upward along the oil rack slide rod. At the same time, the second actuator controller reduces the opening of the cooling air valve and reduces the air speed. When the actual temperature of the top of the oil rack reaches 29-31℃, the actual oil rack height measured by the distance measuring instrument is 920mm. At this time, both the actual oil rack height and the actual temperature of the top of the oil rack are within the set range. The deviation display screen returns to normal color, the alarm is cleared, and the automatic adjustment of the spinning cooling system is completed.

[0139] The yarn obtained in Example 4 had a yarn unevenness CV value of 1.01%, an average yarn unevenness coefficient U value of 0.81%, and a half-inhibition value of 0.69% (the test conditions for yarn unevenness CV value, average yarn unevenness coefficient U value, and half-inhibition value were: test speed of 400m / min, test time of 1min, measurement groove width of 0.36mm, twister: S twist, twisting speed of 22000r / min, nominal count of 83dtex / 72f), and a dyeing uniformity of 4.5 grade.

[0140] Comparative Example 4

[0141] A method for automatic adjustment of filament cooling and forming is different from Example 4 only in that the empirical constant is 3.

[0142] The final yarn had an unevenness CV value of 1.69%, an average unevenness coefficient U value of 1.33%, and a half-inhibition value of 0.93% (the test conditions for unevenness CV, average unevenness coefficient U, and half-inhibition value were: test speed of 400 m / min, test time of 1 min, measurement groove width of 0.36 mm, twister: S twist, twisting speed of 22000 r / min, nominal count of 83 dtex / 72 f), and a dyeing uniformity of 3.0 grade.

[0143] Compared to Example 4, the yarn unevenness coefficient (CV) of the yarn obtained in Comparative Example 4 increased by 67.3%, the average difference coefficient of unevenness (U) increased by 64.2%, and the half-suppression value increased by 34.8%. This is because the yarn specifications before the variety change were 83 dtex / 36f, the actual spinneret height was 1050 mm, the cooling air velocity was 0.4 m / s, the actual spinneret height was relatively large, the spinneret was far from the spinneret, the cooling air velocity was moderate, and the dpf was relatively large. After changing to 83 dtex / 72f, the dpf decreased significantly, and the requirement for cooling air velocity also decreased significantly. The empirical constant of Comparative Example 4 was 3, and the calculated theoretical spinneret height was 1106 mm. The set range of the spinneret height was 1056-1156 mm, which was larger than the actual spinneret height of 1050 mm before the change. The actual spinneret height was adjusted to 1056-1156 mm. Within the range of mm, the actual temperature at the top of the oil rack is <27℃, exceeding the set range by 30±1℃. It is necessary to continuously reduce the opening of the cooling air valve until the cooling air velocity is 0.1m / s. When the cooling air velocity is too low, on the one hand, the interference of outdoor airflow on the filament increases, and on the other hand, the solidification speed of the filament slows down, increasing the factors of filament drift and vibration, thus affecting the uniformity of the filament. After forming, the linear density in the length direction is uneven, the measured unevenness rate is too large, and the dyeing is also uneven, which is a defective product. This shows that when the empirical constant is 3, the empirical constant is too large, which will lead to an increase in the unevenness rate and have an adverse effect on product quality.

Claims

1. A method for automatically adjusting the cooling and forming of a yarn, comprising the steps of stopping spinning for a change in variety and a spinning process after the change in variety, characterized in that, when stopping spinning for a change in variety, the following steps are further performed: calculating the theoretical oil height of the changed variety and measuring the actual oil height; comparing the actual oil height with the theoretical oil height ± height deviation value; if the actual oil height < the theoretical oil height - height deviation value, increasing the oil height until the theoretical oil height - height deviation value ≤ the actual oil height ≤ the theoretical oil height + height deviation value; if the actual oil height > the theoretical oil height + height deviation value, decreasing the oil height until the theoretical oil height - height deviation value ≤ the actual oil height ≤ the theoretical oil height + height deviation value; if the theoretical oil height - height deviation value ≤ the actual oil height ≤ the theoretical oil height + height deviation value, the oil height remains unchanged; the formula for calculating the theoretical oil height is as follows: theoretical oil height = empirical constant × solidification distance; the value range of the empirical constant is 1.5-2.5; the spinning process after the change in variety is as follows: Curing distance X X X 1000, unit of curing distance is mm; wherein d0 is the diameter of the spinneret hole, in m; t1 is the temperature of the melt exiting the spinneret hole, in °C; t2 is the glass transition temperature of the filaments, in °C; t is the temperature of the cooling air, in °C; G is the throughput of the individual spinneret hole, in kg / h; C is the specific heat capacity of the melt, in kJ / (kg °C); h is the heat transfer coefficient, taken as a fixed value of 135 kJ / (m 2 ·h·°C); e is the base of the natural logarithm, taken as a fixed value of 2.718; and ln is the natural logarithm. In one embodiment, the process is carried out at a temperature of the melt exiting the spinneret hole of from 250 to 300 °C, preferably from 260 to 290 °C, more preferably from 265 to 285 °C, and most preferably from 270 to 280 °C. in the spinning process, a preset temperature is set for the top of the oil column, the actual temperature of the top of the oil column is monitored in real time, and the actual temperature of the top of the oil column is compared with the preset temperature of the top of the oil column ± temperature deviation value; the preset temperature is 25-30℃, and the temperature deviation value is 1-2℃; if the actual temperature of the top of the oil column < the preset temperature of the top of the oil column - temperature deviation value, the oil height is decreased, and the air valve opening of the cooling air is also decreased until the preset temperature of the top of the oil column - temperature deviation value ≤ the actual temperature of the top of the oil column ≤ the preset temperature of the top of the oil column + temperature deviation value, and the air valve opening of the cooling air is set to have a minimum value; when the air valve opening of the cooling air reaches the minimum value, if the actual oil height > the theoretical oil height + height deviation value or the actual oil height < the theoretical oil height - height deviation value, the system is stopped for inspection of the cooling air supply system; if the actual temperature of the top of the oil column > the preset temperature of the top of the oil column + temperature deviation value, the oil height is increased, and the air valve opening of the cooling air is also increased until the preset temperature of the top of the oil column - temperature deviation value ≤ the actual temperature of the top of the oil column ≤ the preset temperature of the top of the oil column + temperature deviation value, and the air valve opening of the cooling air is set to have a maximum value; when the air valve opening of the cooling air reaches the maximum value, if the actual oil height > the theoretical oil height + height deviation value or the actual oil height < the theoretical oil height - height deviation value, the system is stopped for inspection of the cooling air supply system; if the preset temperature of the top of the oil column - temperature deviation value ≤ the actual temperature of the top of the oil column ≤ the preset temperature of the top of the oil column + temperature deviation value, the oil height and the air valve opening of the cooling air remain unchanged, and the spinning continues normally. The calculation of the theoretical oil height of the changed variety is completed by an SMU setter, the measurement of the actual oil height is completed by a range finder, and the comparison of the actual oil height with the theoretical oil height ± height deviation value is completed by the SMU setter.

2. A method of automatic regulation of the cooling of a strand as claimed in claim 1, characterized in that, The height deviation value is 50-100mm.

3. A method of automatic regulation of the cooling of a strand as claimed in claim 1, characterized in that, ​ 4. A method of automatic regulation of the cooling and shaping of a strand as claimed in claim 1, characterized in that, With the experience constant in the range of 1.5-2.5 and the preset temperature in the range of 25-30℃, the CV value of the evenness of the cooled yarn is tested, when the CV value of the evenness reaches the minimum, the corresponding experience constant value is the best experience constant value, and the corresponding preset temperature is the best preset temperature.

5. A method of automatic regulation of the cooling and shaping of a strand as claimed in claim 1, characterized in that, 0% < the opening of the cooling air valve ≤ 100%.

6. A method of automatic regulation of the cooling and shaping of a strand as claimed in claim 1, characterized in that, The preset temperature of the temperature of the top of the oil rack is completed by the SMU setter, and the actual temperature of the top of the oil rack is monitored in real time by the temperature sensor, which is installed on the top of the oil rack. The SMU setter is used to compare the actual temperature of the top of the oil rack with the preset temperature of the top of the oil rack ± temperature deviation value.

7. A method of automatic regulation of the cooling and shaping of a strand as claimed in claim 1, characterized in that, The increase and decrease of the opening of the cooling air valve is completed by the SMU setter and the second execution controller, which is connected with the SMU setter and the cooling air valve.

8. A method of automatic regulation of cooling of a strand as claimed in any one of claims 1-7, characterized in that, The increase and decrease of the height of the oil rack is completed by the SMU setter, the first execution controller, the cylinder, the oil rack slide rod and the slide sleeve. The slide sleeve is fixed on the side of the oil rack, the oil rack slide rod is vertically fixed, the slide sleeve is sleeved on the oil rack slide rod in the up-down sliding mode, the working end of the piston rod of the cylinder is fixedly connected with the bottom of the oil rack, the first execution controller is connected with the SMU setter and the cylinder, and the SMU setter controls the working end of the piston rod of the cylinder and the oil rack to move upward or downward through the first execution controller, so as to respectively complete the decrease or increase of the height of the oil rack.

Images